Weighted Averaging

Interpretation of petrophysical log is one of the most useful and important
tools in petroleum geology. Well logs help determine the physical characteristics
of a reservoir, such as lithology, porosity, permeability, producer regions
and their depth and thickness, and also differentiating between oil and gas
and water in a reservoir and defining hydrocarbon reserve. A continual record
of the physical characteristics of rocks in various depths is called well logs.
Petrophysical logs usually include gamma ray, spontaneous potential, resistance,
density, neutron, nuclear magnetic resonance, and sonic. The purpose
of this study is to determine those characteristics of the reservoir that cannot
be specified directly through present measuring well logs, using an intelligent
problem-solving system of neuro-fuzzy. In this study, porosity and
permeability are determined as two of the most important reservoir characteristics
having much influence on reservoir understanding, reservoir
reserve, and capability of reservoir production. The system of determining
reservoir characteristics (neuro-fuzzy) was tested on collected well log data
from oil and gas fields in the south of Iran. The most important result
obtained in this study is that if all data influencing one of the reservoir
characteristics are presented to the neuro-fuzzy system, then this system
will be an excellent model with low error for determining all of the complex
characteristics of the reservoir. These produced intelligent systems predict
porosity and permeability completely on training and testing data and the
correlation coefficient is near 1 and normalized mean square error is near to
zero. Engineers and researchers can predict the reservoir characteristics with
very good precision by these intelligent systems. The results of this study
prove that a neuro-fuzzy intelligent system is a very powerful tool for
determining permeability and porosity at the wells of a naturally fractured
gas condensate reservoir. It is the first time to predict porosity and permeability
from well logs using adaptive neuro-fuzzy inference system in a
naturally fractured gas-condensate reservoir in Khuff Formation (Kangan
and Upper Dalan Formation), which is a heterogeneous formation with a
wide range of permeability and porosity in the Middle East; this method
predicts permeability and porosity precisely in this heterogeneous formation.
The other novelty of this study is the choice of appropriate input parameters
to determine porosity and permeability precisely. Because of the heterogeneous
condition of naturally fractured gas-condensate reservoirs in Khuff
Formation, the appropriate input parameters cause the system to train
optimally and thus increase the system ability to estimate the output in
various conditions precisely.

Estimation of average treatment effects under unconfoundedness or exogenous treatment assignment is often hampered by lack of overlap in the covariate distributions. This lack of overlap can lead to imprecise estimates and can make commonly used estimators sensitive to the choice of specification. In such cases researchers have often used informal methods for trimming the sample. In this paper we develop a systematic approach to addressing such lack of overlap. We characterize optimal subsamples for which the average treatment effect can be estimated most precisely, as well as optimally weighted average treatment effects. Under some conditions the optimal selection rules depend solely on the propensity score. For a wide range of distributions a good approximation to the optimal rule is provided by the simple selection rule to drop all units with estimated propensity scores outside the range [0.1,0.9].

In this article, we propose a novel beta binomial OWA operator (BBN-OWAO) based on the beta binomial distribution. The proposed biparametric operator can generate an unlimited number of weight vectors, irrespective of the total number of arguments to be aggregated, for a given level of optimism/pessimism (orness/andness). Our main objective is to develop a generalized family of constant-orness OWAO that encompasses nearly all constant-orness members. It generalizes well-known Broda-Kendall, Hurwicz, Binomial, Stancu, InHyp OWAOs, and many more. The BBN-OWAO allows decision makers to customize its parameters in accordance with their preferences. As a result, the BBN-OWAO enables decision makers to model a wide range of situations with greater flexibility. This study explores some additional interesting properties of the proposed operator, highlighting its capability to produce two consecutive identical weights. We also compute and demonstrate that the maximum entropy (Shannon) of the BBN-OWAO aligns very closely with the existing analytical results. Finally, we provide an example illustrating its practical application, demonstrated through a case study on player selection for a cricket team.

A natural, altered zircon crystal from an alkaline pegmatite from the Zomba-Malosa Complex of the Chilwa Alkaline Province in Malawi has been studied by a wide range of analytical techniques to understand the alteration process. The investigated zircon shows two texturally and chemically different domains. Whereas the central parts of the grain (zircon I) appear homogeneous in backscattered electron images and are characterised by high concentrations of trace elements, particularly Th, U, and Y, the outer regions (zircon II) contain significantly less trace elements, numerous pores, and inclusions of thorite, ytttrialite, and fergusonite. Zircon II contains very low or undetectable concentrations of non-formula elements such as Ca, Al, and Fe, which are commonly observed in high concentrations in altered radiation-damaged zircon. U-Pb dating of both zircon domains by LA-ICPMS and SHRIMP yielded statistically indistinguishable U-Pb weighted average ages of 119.3 ± 2.1 (2r) and 118 ± 1.2 (2r) Ma, respectively, demonstrating that the zircon had not accumulated a significant amount of self-irradiation damage at the time of the alteration event. Electron microprobe dating of thorite inclusions in zircon II yielded a Th-U-total Pb model age of 122 ± 5 (2r) Ma, supporting the age relationship between both zircon domains. The hydrothermal solution responsible for the alteration of the investigated zircon was alkaline and rich in CO 3 2-, as suggested by the occurrence of REE carbonates and CO 2 -bearing fluid inclusions. The alteration of the crystalline, trace element-rich zircon is explained by an interface-coupled dissolution-reprecipitation mechanism. During such a process, the congruent dissolution of the trace element-rich parent zircon I was spatially and temporally coupled to the precipitation of the trace element-poor zircon II at an inward moving dissolution-precipitation front. The driving force for such a process was merely the difference between the solubility of the trace element-rich and -poor zircon in the hydrothermal solution. The replacement process and the occurrence of mineral inclusions and porosity in the product zircon II is explained by the thermodynamics of solid solution-aqueous solution systems.

A natural, altered zircon crystal from an alkaline pegmatite from the Zomba-Malosa Complex of the Chilwa Alkaline Province in Malawi has been studied by a wide range of analytical techniques to understand the alteration process. The investigated zircon shows two texturally and chemically different domains. Whereas the central parts of the grain (zircon I) appear homogeneous in backscattered electron images and are characterised by high concentrations of trace elements, particularly Th, U, and Y, the outer regions (zircon II) contain significantly less trace elements, numerous pores, and inclusions of thorite, ytttrialite, and fergusonite. Zircon II contains very low or undetectable concentrations of non-formula elements such as Ca, Al, and Fe, which are commonly observed in high concentrations in altered radiation-damaged zircon. U-Pb dating of both zircon domains by LA-ICPMS and SHRIMP yielded statistically indistinguishable U-Pb weighted average ages of 119.3 ± 2.1 (2r) and 118 ± 1.2 (2r) Ma, respectively, demonstrating that the zircon had not accumulated a significant amount of self-irradiation damage at the time of the alteration event. Electron microprobe dating of thorite inclusions in zircon II yielded a Th-U-total Pb model age of 122 ± 5 (2r) Ma, supporting the age relationship between both zircon domains. The hydrothermal solution responsible for the alteration of the investigated zircon was alkaline and rich in CO 3 2-, as suggested by the occurrence of REE carbonates and CO 2 -bearing fluid inclusions. The alteration of the crystalline, trace element-rich zircon is explained by an interface-coupled dissolution-reprecipitation mechanism. During such a process, the congruent dissolution of the trace element-rich parent zircon I was spatially and temporally coupled to the precipitation of the trace element-poor zircon II at an inward moving dissolution-precipitation front. The driving force for such a process was merely the difference between the solubility of the trace element-rich and -poor zircon in the hydrothermal solution. The replacement process and the occurrence of mineral inclusions and porosity in the product zircon II is explained by the thermodynamics of solid solution-aqueous solution systems.

The capsular components of the human pathogen Cryptococcus neoformans are transported to the extracellular space and then used for capsule enlargement by distal growth. It is not clear, however, how the glucuronoxylomannan (GXM) fibers are incorporated into the capsule. In the present study, we show that concentration of C. neoformans culture supernatants by ultrafiltration results in the formation of highly viscous films containing pure polysaccharide, providing a novel, nondenaturing, and extremely rapid method to isolate extracellular GXM. The weight-averaged molecular mass of GXM in the film, determined using multiangle laser light scattering, was ninefold smaller than that of GXM purified from culture supernatants by differential precipitation with cetyl trimethyl ammonium bromide (CTAB). Polysaccharides obtained either by ultrafiltration or by CTAB-mediated precipitation showed different reactivities with GXM-specific monoclonal antibodies. Viscosity analysis associated with i...

Carrageenan was isolated under different extraction conditions from Kappaphycus alvarezii collected in North Sulawesi, Indonesia. Its gel properties include very strong elasticity even at low concentrations. Molecular weight and rheological properties were obtained by gel permeation chromatography and dynamic viscoelasticity measurements in order to clarify the average molecular weight at various extraction temperatures (50, 70, 90°C) and times (1, 3, 5 h), as well as gel formation ability. The results showed that both the weight-average and the number-average molecular weight decreased with increasing extraction temperature. However, the gelation rate of the carrageenan was found to be constant at around 40°C, whereas the storage modulus, G′, and loss modulus, G″, of the gels differed from each other. Gel properties . Loss modulus . Number average molecular weight . Storage modulus . Weight average molecular weight Abbreviations M w weight average molecular weight M n number average molecular weight Symbols G′ storage modulus G″ loss modulus

Intercept-based methods of generating a point estimate of a calibrated radiocarbon date are very popular, but exhibit undesirable behaviour. They are highly sensitive to the mean of the radiocarbon date and to adjustments of the calibration curve. Other methods give more stable results. The weighted average of the probability distribution function is recommended as the best central-point estimate, but more consideration should be given to using the full probability distribution rather than a point estimate in developing age-depth models.

This paper first describes the atmospheric correction algorithm for OCTS visible band data used at NASDA/EOC. Sharing a basic structure with Gordon and Wang's SeaWiFS algorithm, it uses 10 candidate aerosol models including the "Asian dust model" introduced in consideration of the unique feature of aerosols over the east Asian waters. Based on the observations at 670 and 865 nm bands, the algorithm selects a pair of aerosol models that account best for the observed spectral reflectances, and synthesizes the aerosol reflectance used for the atmospheric correction. Two different schemes for determining the value of the parameter for the aerosol model selection are presented and their anticipated estimation error is analyzed in terms of retrieved water reflectance at 443 nm. The results of our numerical simulation show that the standard deviation of the estimation error of the "weighted average" scheme is mostly within the permissible level of ±0.002, reducing the error by 18% on average compared to the "simple average" scheme. The paper further discusses the expected error under the old CZCS-type atmospheric correction, which assumes constant aerosol optical properties throughout the given image. Although our algorithm has a better performance than the CZCS algorithm, further analysis shows that the error induced by the assumption taken in the algorithm that the water-leaving radiance at 670 nm band is negligibly small may be large in high pigment concentration waters, indicating the necessity for future improvements.

A total of 59 rainwater samples were collected during the winter and monsoon at Dayalbagh, Agra. This site is relatively free from the influence of anthropogenic emissions and the volume-weighted average concentrations (VWA) of formate in the winter and monsoon were 22.5 -f 6, 16.1 f 3 while acetate VWAs were 17.1 -f 5 and 13.8 f 3 pmol l-l, respectively. Although the VWAs varied between seasons, it was not statistically different. Total deposition (in mmoi m-') varied between season (winter formate, 1.4; acetate, 1.1; monsoon formate, 7.4; acetate, 6.4). A difference in VWA values may have occurred as a result of the dilution factor; the total rain depth from collected samples in the monsoon was 46 cm while that in winter was 6.3 cm. Sources at this site may be anthropogenic and natural; scavenging from the vapour phase, washout of soil particles and emissions from vegetative sources are probably important sources for formate and acetate.

I thank Bill Dupor, Joao Gomes, and Skander van den Heuvel for helpful discussion, Martin Gervais and Carlos Garriga for helpful correspondence, the Penn Macro Lunch Group, seminars at Carnegie-Mellon University, the University of Rochester, and the University of Washington, and two referees and the editor for helpful comments. The views expressed herein are those of the authors and not necessarily those of the National Bureau of Economic Research.

The objective of this study was to characterize the small ruminant value chain in the Northern Jordan, map out its stakeholders and their roles, and identify the challenges facing it in order to improve its production efficiency and ensure its sustainability. Data were obtained from a sampling survey of 134 small ruminant holders located in the Northern region of Jordan. The survey focused on the main aspects of small ruminant production as input supplies, husbandry practices, processing, marketing, and consumption. Also, individual semi-structured interviews of 20 animal health care suppliers, 25 dairy processors, 25 butchers, and 20 traders, were used to undertake small ruminant value chain analysis. The results showed that the small ruminant value chain in the study area involved multiple actors with diverse roles represented by input suppliers, producers, traders, processors, and consumers. Present findings indicated that the value chain associated with small ruminants is primarily limited by the spatial constraints posed by the expansion of urban areas into rangeland regions, government policies concerning the management of forested areas, as well as the cultivation and afforestation of privately owned land. Additionally, the high production costs coupled with low milk prices and competition of imported meats, and production management also contributed to the constraints in the value chain. Based on these findings, it can be concluded that the small ruminant value chain is poorly organized and lack strong interconnections among its stakeholders. Therefore, there is a clear necessity to establish effective linkages between all stakeholders involved in the small ruminant value chain within the study area. Furthermore, addressing the weaknesses and threats identified within this sector is first step in order to enhance the production and marketing of small ruminants.

This paper shows that the distribution of observed consumption is not a good proxy for the distribution of heterogeneous consumers when the current tariff is an increasing block tariff. We use a two step method to recover the "true" distribution of consumers. First, we estimate the demand function induced by the current tariff. Second, using the demand system, we specify the distribution of consumers as a function of observed consumption to recover the true distribution. Finally, we design a new two-part tariff which allows us to evaluate the equity of the existence of an increasing block tariff.

Brazil has experienced,crucial changes,in its in‡ation process since the adoption,of in‡ation targeting,in mid,1999. This article addresses,changes,in the analytical framework,employed to track the in‡ation dynamics, speci…cally the relevance of an explicit target for in‡ation. A New-Keynesian,Phillips curve (NKPC) is derived,incorporating,indexation,not only to past in‡ation but also to in‡ation targets, generalizing the Gali and Gertler (1999) hybrid curve. In our modeling, …rms that do not optimally set their prices in a given period adjust them,only by indexing,their previous,prices to a weighted,average,of the in‡ation target and lagged in‡ation. In such a framework, the impact of in‡ation targets on agents’ decisions regarding,the supply,side can be analytically,measured,by the parameter,associated,to the in‡ation target. It is shown,that in‡ation target a¤ects the welfare-based,monetary,policy objective function by penalizing deviations,of actual in‡ation from target instead ...

We analyzed the dynamics of freshwater marsh vegetation of Taylor Slough in eastern Everglades National Park for the 1979 to 2003 period, focusing on cover of individual plant species and on cover and composition of marsh communities in areas potentially influenced by a canal pump station (''S332'') and its successor station (''S332D''). Vegetation change analysis incorporated the hydrologic record at these sites for three intervals: pre-S332 (1961-1980), S332 (1980-1999), post-S332 (1999-2002). During S332 and post-S332 intervals, water level in Taylor Slough was affected by operations of S332 and S332D. To relate vegetation change to plot-level hydrological conditions in Taylor Slough, we developed a weighted averaging regression and calibration model (WA) using data from the marl prairies of Everglades National Park and Big Cypress National Preserve. We examined vegetation pattern along five transects. Transects 1-3 were established in 1979 south of the water delivery structures, and were influenced by their operations. Transects 4 and 5 were established in 1997, the latter west of these structures and possibly under their influence. Transect 4 was established in the northern drainage basin of Taylor Slough, beyond the likely zones of influence of S332 and S332D. The composition of all three southern transects changed similarly after 1979. Where muhly grass (Muhlenbergia capillaris var. filipes) was once dominant, sawgrass (Cladium jamaicense), replaced it, while where sawgrass initially predominated, hydric species such as spikerush (Eleocharis cellulosa Torr.) overtook it. Most of the changes in species dominance in Transects 1-3 occurred after 1992, were mostly in place by 1995-1996, and continued through 1999, indicating how rapidly vegetation in seasonal Everglades marshes can respond to hydrological modifications. During the post-S332 period, these long-term trends began reversing. In the two northern transects, total cover and dominance of both muhly grass and sawgrass increased from 1997 to 2003. Thus, during the 1990's, vegetation composition south of S332 became more like that of long hydroperiod marshes, but afterward it partially returned to its 1979 condition, i.e., a community characteristic of less prolonged flooding. In contrast, the vegetation change along the two northern transects since 1997 showed little relationship to hydrologic status.

Jerusalem artichoke (Helianthus tuberosus L.) has long been cultivated as a vegetable and as a source of fructans (inulin) for pharmaceutical applications in diabetes and obesity prevention. However, transcriptomic and genomic data for Jerusalem artichoke remain scarce. In this study, Illumina RNA sequencing (RNA-Seq) was performed on samples from Jerusalem artichoke leaves, roots, stems and two different tuber tissues (early and late tuber development). Data were used for de novo assembly and characterization of the transcriptome. In total 206,215,632 paired-end reads were generated. These were assembled into 66,322 loci with 272,548 transcripts. Loci were annotated by querying against the NCBI non-redundant, Phytozome and UniProt databases, and 40,215 loci were homologous to existing database sequences. Gene Ontology terms were assigned to 19,848 loci, 15,434 loci were matched to 25 Clusters of Eukaryotic Orthologous Groups classifications, and 11,844 loci were classified into 142 Kyoto Encyclopedia of Genes and Genomes pathways. The assembled loci also contained 10,778 potential simple sequence repeats. The newly assembled transcriptome was used to identify loci with tissue-specific differential expression patterns. In total, 670 loci exhibited tissue-specific expression, and a subset of these were confirmed using RT-PCR and qRT-PCR. Gene expression related to inulin biosynthesis in tuber tissue was also investigated. Exsiting genetic and genomic data for H. tuberosus are scarce. The sequence resources developed in this study will enable the analysis of thousands of transcripts and will thus accelerate marker-assisted breeding studies and studies of inulin biosynthesis in Jerusalem artichoke.

Recently, Chen et al. proposed a method for compressing color-quantized images that is based on a binary tree representation of colors and on context-based arithmetic coding with variable size templates. In this paper, we address the problem of context adaptation and we propose a model that provides improvements in the lossless compression capabilities of Chen's method.

Capacity choice or expansion, whether organic or via mergers and acquisitions, creates firms of widely varying scales. The ex-post profitability of such a transformed firm relative to its original size will typically be evaluated on ratio (rate) measures like earnings per share or profits to asset ratio, as such are the only meaningful ways to compare profitability of firms of substantially different sizes. It thus seems desirable that ex-ante capacity selection decisions will also be guided by a ratio objective. We explore capacity choice decisions under demand uncertainty through the ratio measures: (1) Expected ''newsvendor'' (i.e., single period) costs per unit capacity. ( ) Expected (newsvendor) profit per unit of capacity. (3) Expected profit per costs of acquiring capacity. (4) A weighted average of a ratio and non-ratio objectives. We allow the capacity-acquisition costs and capacity's production capability to be general non-linear functions. Cost and profit objectives cease to be equivalent when ratio objectives are involved. We show that cost ratio optimizers will select a larger capacity than absolute cost optimizers, while profit ratio optimizers will select smaller capacities than absolute counterpart. We provide examples which show that the difference in optimal capacities, and the associated difference in objective value can be substantial. We also perform comparative statics analyses of the effect of change in item's shortage cost and of stochastic shifts in demand.

Two short sediment cores from the Archipelago Sea in the northern Baltic Sea were examined for their siliceous microfossils in order to study recent eutrophication in the area. The diatom record was divided into diatom assemblage zones. Locally weighted weighted averaging regression and calibration was applied for the quantitative reconstruction of past TN concentrations. The cores were dated using radiometric ( 210 Pb, 226 Ra and 137 Cs) methods. The diatom assemblages in the topmost zones in both cores indicate eutrophication during the last decade. TN reconstructions partially fail to trace the actual measured TN concentrations. Especially from the late 1980s to the mid 1990s, the dominating diatom species are more influenced by other factors, such as the length of the ice season, than by nutrient concentrations. It seems that in the Archipelago Sea, diatom assemblages are principally governed by climatic fluctuations with a moderate influence of eutrophication in recent years. The peak in sedimentation in the early 1990s coincides with the short ice seasons indicating that sedimentation may increase with decreasing ice-cover extent due to warming climate.

ABSTRACTThe accuracy of using near‐infrared spectroscopy (NIRS) for predicting 186 grain, milling, flour, dough, and breadmaking quality parameters of 100 hard red winter (HRW) and 98 hard red spring (HRS) wheat and flour samples was evaluated. NIRS shows the potential for predicting protein content, moisture content, and flour color b* values with accuracies suitable for process control (R2 > 0.97). Many other parameters were predicted with accuracies suitable for rough screening including test weight, average single kernel diameter and moisture content, SDS sedimentation volume, color a* values, total gluten content, mixograph, farinograph, and alveograph parameters, loaf volume, specific loaf volume, baking water absorption and mix time, gliadin and glutenin content, flour particle size, and the percentage of dark hard and vitreous kernels. Similar results were seen when analyzing data from either HRW or HRS wheat, and when predicting quality using spectra from either grain or...

We investigated the potential for using diatoms to monitor and assess nutrient enrichment in coastal plain streams using weighted-averaging inference models and diatom trophic indices. Samples were collected from low-gradient, clay-to sand-bottom streams in New Jersey (NJ), USA, using artificial substrates (diatometers). Multivariate analysis showed that conductivity was overall the most important explanatory variable. Total phosphorus (TP) explained a significant proportion of the variation in diatom species composition. There was statistical justification for development of inference models for TP but not for total nitrogen (TN). We developed and tested models for inferring TP using weighted-averaging (WA) and weighted-averaging partial least squares (WA-PLS) regression and calibration techniques. We also created a diatom TP index by rescaling the inferred TP values. WA-PLS provided the best model (n = 38), which showed moderate predictive ability (r boot 2 = 0.43; RMSEP boot = 0.30 log 10 lg l -1 TP); it performed best at lower TP concentrations and tended to underestimate values above 100 lg l -1 . The TP index performed well; it assigned the majority of the index scores to the correct nutrient category. TP models and indices developed for the Coastal Plain had lower predictive ability than those developed for northern NJ and streams in other comparable geographic regions of the US. This lower performance can be attributed primarily to a data gap in the TP gradient in the calibration dataset (lack of sites with TP concentrations between 240 and 560 lg l -1 ), and a smaller number of samples. We conclude that diatom-based TP inference models and artificial substrate sampling are useful for assessing and monitoring nutrient enrichment in coastal plain streams. Given the worldwide distribution of streams similar to those in this study, these tools should be widely applicable.

Fifty-two accessions of Canarium involving seven species, C. ovatum, C. album, C. megalanthum, C. harveyi, C. indicum, C. mehenbethene, and C. odontophyllum were studied for isozyme polymorphisms. Starch gel electrophoresis with a histidine-citrate buffer system (pH 6.5) was employed to assay six enzymes: LAP, MDH, GPI, PGM, TPI and UGPP. Species were polymorphic for most of the six enzyme systems assayed and the level of phenotypic polymorphism for different species and enzymes assayed ranged from 0 to 0.88, with an overall average of 0.28. The weighted average of polymorphisms across different enzyme systems for different species ranged from 0.16 for C. indicum to 0.47 for C. ovatum, with an overall average of 0.26. On average, LAP was the most polymorphic enzyme (0.43) followed by GPI (0.38), MDH (0.27), UGPP (0.26), PGM (0.18), and TPI (0.13). The complexity of isozyme phenotypes indicates that interspecific hybridization and polyploidy might have played a major role in the evolution of Canarium species. Geographic speciation in Canarium was not apparent from the phenetic analysis of the isozyme data. 0 Elsevier Science B.V.

If one firm buys inputs from a competitor, the input price may be used to internalize the competition between the firms. Thus, positive pricing pressure may arise if one firm starts to buy inputs from a competitor. Conversely, pricing pressure may be significantly reduced if two firms with vertical restraints merge, as pre-merger competition already was internalised through the input price. We present a method for adjusting the formula of Hausman et al. (2011), in order to predict correct pricing pressures not only for horizontal mergers, but also for other structural market changes. Short phrases: Merger analysis, Upward Pricing Pressure, Vertical restrictions JEL Classification: L44, L42

The glass transition during bulk polymerization was studied in free-radical crosslinking copolymerization (FCC) of ethyl methacrylate (EMA), using both the steady-state fluorescence (SSF) and the fast transient fluorescence (FTRF) techniques. Pyrene (Py) was used as a fluorescence probe. Changes in the viscosity of the pregel solutions due to gel formation dramatically enhance the fluorescent yield of Py molecules. The reaction time at which the Py intensity and lifetime exhibit a sudden increase corresponds to the reaction time at which the rate of polymerization becomes maximum resulting from the gel effect. This effect is used to study the gelation of EMA, as a function of time, at various crosslinker concentrations and different temperatures. The results were interpreted in the view of percolation theory. The gel fraction, and weight average degree of polymerization, exponents ¼ 0.37 AE 0.01, ¼ 1.71 AE 0.04 and ¼ 0.36 AE 0.002, ¼ 1.687 AE 0.01 are found in agreement with percolation results for SSF and FTRF measurements, respectively.

A mosaic of four UIT far-UV (FUV) (λ ef f = 1620 Å) images, with derived stellar and HII region photometry, is presented for most of the Bar of the SMC. The UV morphology of the SMC's Bar shows that recent star formation there has left striking features including: a) four concentrations of UV-bright stars spread from northeast to southwest at nearly equal (∼30 arcmin=0.5 kpc) spacings; b) one of the concentrations, near DEM 55, comprises a well-defined 8-arcmin diameter ring surrounded by a larger Hα ring, suggestive of sequential star formation. FUV PSF photometry is obtained for 11,306 stars in the FUV images, resulting in magnitudes m(162). We present a FUV luminosity function for the SMC bar, complete to m(162)∼14.5. Detected objects are well correlated with other SMC Population I material; of 711 Hα emission-line stars and small nebulae within the UIT fields of view, 520 are identified with FUV sources. The FUV photometry is compared with available ground-based catalogs of supergiants, yielding 191 detections of 195 supergiants with spectral type earlier than F0 in the UIT fields. The (m(162)-V) color for supergiants is a sensitive measure of spectral type. The bluest observed colors for each type agree well with colors computed from unreddened Galactic spectral atlas stars

This paper uses data from the Philippines to examine the impact of trade on workers. The empirical analysis is based on two exercises. The first uses industry-level panel data from the Philippines' manufacturing sector to examine how trade has affected total employment and average wages in 28 manufacturing industries. A key result which emerges is that greater openness -whether measured in terms of increasing trade shares or reduction in average tariff rates -has had a weak impact on total employment and average real wages. Our second exercise, which uses labor force survey data and explicitly recognizes the significant degree of heterogeneity in worker characteristics, examines the effects of trade on wage inequality between educated and relatively uneducated workers. While an increase in the supply of education is found to be an important factor in exerting downward pressure on wage inequalities in the Philippines, our results also indicate that the expansion of trade has led to an increase in the relative demand for unskilled workers as standard trade models would predict. * We are extremely grateful to the International Center for the Study of East Asian Development (Kitakyushu, Japan) for their generous support of this project. We would like to thank Andy Mason and Emily Cabegin for providing us with the Philippines Labor Force Surveys. Thanks are also due to Emily Cabegin for her valuable help in explaining to us the structure of the Labor Force Survey data set. Finally, we thank Marcelo Olarreaga and Alessandro Nicita of the World Bank for making available their trade and production database for the Philippines and to Andriy Mykytiv for research assistance in analyzing that database.

How should species cover be weighted when calculating average indicator values of vegetation relevés? Location: The Netherlands. Method: Various weighting methods were statistically investigated with 188 relevés from The Netherlands for which accurate groundwater levels were available. For each method the correlation between average Ellenberg indicator value for moisture and mean spring groundwater level was calculated. A permutation test on correlation coefficients revealed whether differences between methods were significant or not. Results: Optimization of a general weighting function did not produce a significantly higher correlation than disregarding cover and calculating the average as the arithmetical mean of indicator values. Giving a higher weight to species at both ends of the indicator scale and using indifferent species as indicators of mediocre conditions did improve the correlation significantly. Weighting species proportionate to their cover yielded a significantly lower correlation than the correlation obtained with the method that disregards cover. A significantly lower correlation was also established when taking into account the fact that cover is related to the growth strategy of species.

We improve estimates of stellar mass and mass-weighted average age of Type Ia supernova (SN Ia) host galaxies by combining UV and near-IR photometry with optical photometry in our analysis. Using 206 SNe Ia drawn from the full three-year SDSS-II Supernova Survey (median redshift of z ≈ 0.2) and multi-wavelength host-galaxy photometry from SDSS, GALEX, and UKIDSS, we present evidence of a correlation (1.9σ confidence level) between the residuals of SNe Ia about the best-fit Hubble relation and the mass-weighted average age of their host galaxies. The trend is such that older galaxies host SNe Ia that are brighter than average after standard light-curve corrections are made. We also confirm, at the 3.0σ level, the trend seen by previous studies that more massive galaxies often host brighter SNe Ia after light-curve correction.

Parameter estimation under model uncertainty is a difficult and fundamental issue in econometrics. This paper compares the performance of various model averaging techniques. In particular, it contrasts Bayesian model averaging (BMA)-currently one of the standard methods used in growth empirics-with a new method called weighted-average least squares (WALS). The new method has two major advantages over BMA: its computational burden is trivial and it is based on a transparent definition of prior ignorance. The theory is applied to and sheds new light on growth empirics where a high degree of model uncertainty is typically present.

Parameter estimation under model uncertainty is a difficult and fundamental issue in econometrics. This paper compares the performance of various model averaging techniques. In particular, it contrasts Bayesian model averaging (BMA)-currently one of the standard methods used in growth empirics-with a new method called weighted-average least squares (WALS). The new method has two major advantages over BMA: its computational burden is trivial and it is based on a transparent definition of prior ignorance. The theory is applied to and sheds new light on growth empirics where a high degree of model uncertainty is typically present.

(24Jan09) an explosive cyclogenesis placed at the Gulf of Vizcaya, reached its maximum intensity with observed surface pressures below 970 hPa on its center. During its path through the south of France there were strong westerly and northwesterly winds over Iberian Peninsula (above 150 km/h). These extreme winds leaved 8 casualties in Catalunya, the northeast region of Spain. The aim of this work is validating the skill of the Spanish Meteorological Agency (AEMET) Short Range Ensemble Prediction System (SREPS) in forecasting this event. Two probabilistic forecasts of wind are compared, a noncalibrated (or raw) and a calibrated one using the Bayesian Model Averaging (BMA). AEMET runs a daily experimental SREPS twice a day (00:00 and 12:00 UTC). This system consists on 25 members that are constructed by integrating five different Limited Area Models (LAMs) at 0.25 degrees of horizontal resolution. Each model uses five different initial and boundary conditions from five Global Models (GMs). Thus it is obtained a probabilistic forecast that takes into account initial, contour and model uncertainties. BMA is a statistical tool for combining predictive Probability Distribution Functions (PDFs) from different sources. BMA predictive PDF is a weighted average of PDFs centered on the individual bias-corrected forecasts. Each weight is a measure of the corresponding forecast skill. Here BMA is applied to calibrate probabilistic forecasts of wind speed. In this work two time forecast ranges (H+60 and H+36) of 10-m wind speed over Catalonia are verified subjectively at 12:00 UTC of 24Jan09 valid time. We focus on the location

(24Jan09) an explosive cyclogenesis placed at the Gulf of Vizcaya, reached its maximum intensity with observed surface pressures below 970 hPa on its center. During its path through the south of France there were strong westerly and northwesterly winds over Iberian Peninsula (above 150 km/h). These extreme winds leaved 8 casualties in Catalunya, the northeast region of Spain. The aim of this work is validating the skill of the Spanish Meteorological Agency (AEMET) Short Range Ensemble Prediction System (SREPS) in forecasting this event. Two probabilistic forecasts of wind are compared, a noncalibrated (or raw) and a calibrated one using the Bayesian Model Averaging (BMA). AEMET runs a daily experimental SREPS twice a day (00:00 and 12:00 UTC). This system consists on 25 members that are constructed by integrating five different Limited Area Models (LAMs) at 0.25 degrees of horizontal resolution. Each model uses five different initial and boundary conditions from five Global Models (GMs). Thus it is obtained a probabilistic forecast that takes into account initial, contour and model uncertainties. BMA is a statistical tool for combining predictive Probability Distribution Functions (PDFs) from different sources. BMA predictive PDF is a weighted average of PDFs centered on the individual bias-corrected forecasts. Each weight is a measure of the corresponding forecast skill. Here BMA is applied to calibrate probabilistic forecasts of wind speed. In this work two time forecast ranges (H+60 and H+36) of 10-m wind speed over Catalonia are verified subjectively at 12:00 UTC of 24Jan09 valid time. We focus on the location

Biofilm modeling is often considered as a complex mathematical subject. This paper evaluates simple equations to describe the basic processes in a biofilm system with the main aim to show several interesting applications. To avoid mathematical complexity the simulations are carried out in a simple spreadsheet. Frequently, only the solution for zeroorder reaction kinetics of the reaction-diffusion equation is used (better known as half-order kinetics). A weighted average of the analytical solutions for zero-and first-order reactions is proposed as basic and useful model to describe steady-state (in biofilm composition) biofilm reactors. This approach is compared with several modeling approaches, such as the simple solution for zero-order reaction and more complex ones (i) direct numerical solution for the diffusion equations, (ii) 1-D AQUASIM and (iii) 2-D modeling. The systems evaluated are single and multiple species biofilms. It is shown that for describing conversions in biofilm reactors, the zero-order solution is generally sufficient; however, for design purposes large deviations of the correct solution can occur. Additionally, the role of diffusion in flocculated and granular sludge systems is discussed. The relation between the measured (apparent) substrate affinity constant and diffusion processes is outlined.

Coal blends combustion is widely practised in blast furnace ironmaking and in coal-fired power stations. It is desirable to be able to characterize the burning performance of coal blends prior to full scale trials. A three-dimensional numerical model is developed to simulate the flow and combustion of a binary coal blend, and validated using measurements from a pilot-scale combustion test rig for three cases. Rather than treating the blend as a single coal with weighted-average properties of its components, in this model, the two component coals in the blend, with individual properties, are tracked separately and undergo individual chemical reactions using individual kinetics. As a result, this model is capable of providing individual information of component coals. In addition, this model includes coaxial lance and three gas streams. Flow pattern features are simulated and combustion behaviours in the combustor are predicted in terms of burnout, particle temperature and volatile content.

We have explained in detail why the canonical partition function of interacting self-avoiding walk (ISAW) is exactly equivalent to the configurational average of the weights associated with growth walks, such as the interacting growth walk (IGW), if the average is taken over the entire genealogical tree of the walk. In this context, we have shown that it is not always possible to factor the density of states out of the canonical partition function if the local growth rule is temperature dependent. We have presented Monte Carlo results for IGWs on a diamond lattice in order to demonstrate that the actual set of IGW configurations available for study is temperature dependent even though the weighted averages lead to the expected thermodynamic behavior of ISAW.

Abstract: Interacting Growth Walks is a recently proposed stochastic model for studying the coil-globule transition of linear polymers. We propose a flat energy histogram version for Interacting Growth Walk. We demonstrate the algorithm on two dimensional square and triangular lattices by calculating the density of energy states of Interacting Self Avoiding Walks.

Truck freight terminals are predominantly located near highways and industrial facilities. This proximity to pollution sources, coupled with meteorological conditions and wind patterns, may affect occupational exposures to particles at these work locations. In order to understand this process, data from an environmental sampling study of particles at US trucking terminals, along with weather and geographic maps, were analyzed to determine the extent to which the transportation of particles from local pollutant sources elevated observed occupational exposures at these locations. To help identify potential upwind sources, wind direction weighted averages and speed measurements were used to construct wind roses, which were superimposed on overhead photos of the terminal and examined for upwind source activity. Statistical tests were performed on these "source" and "non-source" directions to determine whether there were significant differences in observed particle levels between the two groups. Our results provide evidence that nearby upwind pollution sources significantly elevated background concentrations at only a few of the locations sampled, while the majority provided little to no evidence of a significant upwind source effect.

We have obtained a second epoch observation of the Cassiopeia A supernova remnant (SNR) with the Chandra X-ray Observatory to measure detailed X-ray proper motions for the first time. Both epoch observations are 50 ks exposures of the ACIS-S3 chip and they are separated by 2 years. Measurements of the thin Xray continuum dominated filaments located around the edge of the remnant (that are identified with the forward shock) show expansion rates from 0.02% yr −1 to 0.33% yr −1. Many of these filaments are therefore significantly decelerated. Their median value of 0.21% yr −1 is equal to the median expansion of the bright ring (0.21% yr −1) as measured with Einstein and ROSAT. This presents a conundrum if the motion of the bright ring is indicative of the reverse shock speed. We have also re-evaluated the motion of the radio bright ring with emphasis on angle-averaged emissivity profiles. Our new measurement of the expansion of the angle-averaged radio bright ring is 0.07 ± 0.03% yr −1 , somewhat slower than the previous radio measurements of 0.11% yr −1 which were sensitive to the motions of small-scale features. We propose that the expansion of the small-scale bright ring features in the optical, X-ray, and radio do not represent the expansion of the reverse shock, but rather represent a brightness-weighted average of ejecta passing through and being decelerated by the reverse shock. The motion of the reverse shock, itself, is then represented by the motion of the angle-averaged emissivity profile of the radio bright ring.

In vivo random mutagenesis of the polyhydroxyalkanoate (PHA) synthase gene from Aeromonas punctata was performed employing the mutator strain Escherichia coli XL1-Red. About 200,000 mutants were screened on Nile red-containing medium and five mutants with enhanced fluorescence were selected. Four of these mutants exhibited enhanced in vivo and in vitro PHA synthase activity. Mutant M1, which carried the single mutation F518I, showed a five-fold increase in specific PHA synthase activity, whereas the corresponding mediated PHA accumulation increased by 20%, as compared with the wild-type PHA synthase. Mutant M2, which carried the single mutation V214G, showed a twofold increase in specific PHA synthase activity and PHA accumulation only increased by 7%. Overall, the in vitro activities of the overproducing mutants ranged from 1.1to 5-fold more than the wild-type activity, whereas the amounts of accumulated PHA ranged over 107-126% of that of the wild type. Moreover, all mutants mediated synthesis of PHAs with an increased weight average molar mass, but the molar fractions of 3-hydroxybutyrate and 3-hydroxyhexanoate remained almost constant. In vivo random mutagenesis proved to be a versatile tool to isolate mutants exerting improved properties with respect to PHA biosynthesis.

Imprecise or vague importance as well as satisfaction levels of criteria may characterize the evaluation of alternative network security systems and may be treated by the fuzzy set theory. As fuzzy numbers are adopted, the fuzzy weighted averages (FWAs) may become a suitable computation for the fuzzy criteria ratings and fuzzy weightmgs. In this paper, we propose to use the FWA approach that operates on the fuzzy numbers and obtains the fuzzy weighted averages during the evaluations of network security systems. The algorithm constructs a benchmark adjustment solution approach for FWA. A case study of the evaluation of network security systems is provided and demonstrates the usefulness of this study.

Site managers need to be kept abreast of the challenges of ever-changing construction technology, knowledge ideology, management techniques, dynamic nature of construction site works and this requires training and retraining. The aim of this paper is to examine and evaluate the specific training needs of construction site managers handling selected construction projects in Lagos State of Nigeria. A structured questionnaire survey was used to collect information on construction site managers in Lagos State. The data were analysed using descriptive statistics, mean score, weighted average, and t-test distribution. The result of the study revealed that there is common agreement that training of site managers should address human and industrial relations, building production and project management, then communication skills and computing. The paper concludes with recommendation to establish training institutes to take up the managerial training addressing the skill shortages of site managers to enhance efficiency in the construction industry. Field visit with site managers on weekend basis should be considered as the most effective method of training.

Pressure drop is one of the most important characteristics of a fibrous media. While numerous analytical, numerical, and experimental published works are available for predicting the permeability of media made up of fibers with a unimodal fiber diameter distribution (referred to as unimodal media here), there are almost no easy-to-use expressions available for media with a bimodal fiber diameter distribution (referred to as bimodal media). In the present work, the permeability of bimodal media is calculated by solving the Stokes flow governing equations in a series of 3-D virtual geometries that mimic the microstructure of fibrous materials. These simulations are designed to establish a unimodal equivalent diameter for the bimodal media thereby taking advantage of the existing expressions of unimodal materials for permeability prediction. We evaluated eight different methods of defining an equivalent diameter for bimodal media and concluded that the area-weighted average diameter of Brown and Thorpe [2001. Glass-fiber filters with bimodal fiber size distributions. Powder Technology 118, 3-9], volume-weighted resistivity model of Clague and Phillips [1997. A numerical calculation of the hydraulic permeability of three dimensional disordered fibrous media. Physics of Fluids 9 (6), 1562-1572], and the cube root relation of the current paper offer the best predictions for the entire range of mass (number) fractions, 0 n c 1, with fiber diameter ratios, 1 R cf 5, and solidities, 5 15.

In this note, an easy-to-use two-dimensional model is developed to predict the instantaneous pressure drop and collection efficiency of circular pleated filters as a function of time in both the surface and depth filtration regimes. Our model uses average velocity profiles that represent the flow field inside a circular pleated filter to circumvent the need for conducting CPU-intensive CFD calculations to predict the service life of a circular filter. This is accomplished by considering a reasonable dust-cake profile inside the pleat channels as a function of the flow and particles properties, and allowing the cake to grow as the filter continues to collect particles over time. Despite the approximate nature of its predictions, the speed at which a large parameter study can be completed makes the present model very valuable for design and development of circular pleated filters. Using this model for instance, it can be shown quantitatively that circular filters with high inlet-to-outlet diameter ratios outperform their flat counterparts.

Pressure drop is one of the most important characteristics of a fibrous media. While numerous analytical, numerical, and experimental published works are available for predicting the permeability of media made up of fibers with a unimodal fiber diameter distribution (referred to as unimodal media here), there are almost no easy-to-use expressions available for media with a bimodal fiber diameter distribution (referred to as bimodal media). In the present work, the permeability of bimodal media is calculated by solving the Stokes flow governing equations in a series of 3-D virtual geometries that mimic the microstructure of fibrous materials. These simulations are designed to establish a unimodal equivalent diameter for the bimodal media thereby taking advantage of the existing expressions of unimodal materials for permeability prediction. We evaluated eight different methods of defining an equivalent diameter for bimodal media and concluded that the area-weighted average diameter of Brown and Thorpe [2001. Glass-fiber filters with bimodal fiber size distributions. Powder Technology 118, 3-9], volume-weighted resistivity model of Clague and Phillips [1997. A numerical calculation of the hydraulic permeability of three dimensional disordered fibrous media. Physics of Fluids 9 (6), 1562-1572], and the cube root relation of the current paper offer the best predictions for the entire range of mass (number) fractions, 0 n c 1, with fiber diameter ratios, 1 R cf 5, and solidities, 5 15.

In this paper, the optimization of multi-pass milling has been investigated in terms of two objectives: machining time and production cost. An advanced search algorithm-parallel genetic simulated annealing (PGSA)was used to obtain the optimal cutting parameters. In the implementation of PGSA, the fitness assignment is based on the concept of a non-dominated sorting genetic algorithm (NSGA). An application example is given using PGSA, which has been used to find the optimal solutions under four different axial depths of cut on a 37 SUN workstation network simultaneously. In a single run, PGSA can find a Pareto-optimal front which is composed of many Pareto-optimal solutions. A weighted average strategy is then used to find the optimal cutting parameters along the Pareto-optimal front. Finally, based on the concept of dynamic programming, the optimal cutting strategy has been obtained.