Time Use

The development of imitation during the second year of life plays an important role in domains of socio-cognitive development such as language and social learning. Deficits in imitation ability in persons with autism spectrum disorder (ASD) have also been repeatedly documented from toddlerhood into adulthood, raising the possibility that early disruptions in imitation contribute to the onset of ASD and the deficits in language and social interaction that define the disorder. This study prospectively examined the development of imitation between 12 and 24 months of age in 154 infants at familial risk for ASD and 78 typically developing infants who were all later assessed at 36 months for ASD or other developmental delays. The study established a developmental measure of imitation ability, and examined group differences over time, using an analytic Rasch measurement model. Results revealed a unidimensional latent construct of imitation and verified a reliable sequence of imitation skills that was invariant over time for all outcome groups. Results also showed that all groups displayed similar significant linear increases in imitation ability between 12 and 24 months and that these increases were related to individual growth in both expressive language and ratings of social engagement, but not fine motor development. The group of children who developed ASD by age 3 years exhibited delayed imitation development compared to the low-risk typical outcome group across all time-points, but were indistinguishable from other high-risk infants who showed other cognitive delays not related to ASD.

This paper provides a review of the tectonic evolution of central-southern Africa from Mesoproterozoic to earliest Palaeozoic times, using available geological information and a robust U-Pb zircon database. During the late Mesoproterozoic, the southern margin of the Congo-Tanzania-Bangweulu Craton was characterized by suprasubduction-zone magmatism and the accretion of arc and microcontinental fragments. Magmatism within the adjacent Irumide Belt formed by recycling of older continental crust. Ophiolite blocks, possibly part of an olistostromal mélange, are present in a Neoproterozoic sequence overlying the Irumide Belt, and the occurrence of high-pressure/low-temperature subduction-zone metamorphism and protracted Neoproterozoic suprasubduction-zone magmatism demonstrates that there was an ocean to the south (present-day coordinates) of the Congo-Tanzania-Bangweulu Craton until the amalgamation of Gondwana at 550-520 Ma, indicating that the Congo-Tanzania-Bangweulu Craton was not part of Rodinia. On the basis of their different ages and styles of magmatism, the Mesoproterozoic Kibaran Belt, Choma-Kalomo Block and Irumide Belt are not components of the same orogen, therefore precluding a sub-Saharanwide, linked 'Kibaran' (sensu lato) orogenic event. Evidence is presented to illustrate that the Congo-Tanzania-Bangweulu and Kalahari Cratons developed independently until their final collision during the Pan-African Orogeny along the Damara-Lufilian-Zambezi Orogen at c. 550-520 Ma.

In this paper a new pedestrian mobility model for outdoor scenarios is presented. It captures realistic features like moving-in-groups, conscious traveling and smart traveling. The routing algorithm proposed within the model works under a step by step approach, leading users to their destination while, at the same time, using more attractable streets from a pedestrian point of view. The model concept is perfectly generic and applicable to any pedestrian outdoor scenario, provided that the street database and pedestrian traffic information is available. The mobility model was validated using Lisbon's downtown as a case study. The output shows a high correlation between simulated and real data, thus validating the approach.

Microprocessor power has become a first-order constraint at run-time. Designers must employ aggressive power-management techniques at run-time to keep a processor's ballooning power requirements under control. Effective power management benefits from knowledge of run-time microprocessor power consumption in both the core and individual microarchitectural structures, such as caches, queues, and execution units. Increasingly feasible perstructure power-control techniques, such as fine-grain clock gating, power gating, and dynamic voltage/frequency scaling (DVFS), become more effective from run-time estimates of per-structure power. However, run-time computation of per-structure power estimates based on utilization requires daunting numbers of input statistics, which makes per-structure monitoring of run-time power a challenging problem.

The liberalization of electricity markets has forced energy producing companies and traders to calculate costs closer to the profit frontier. Thus, an efficient risk management and risk controlling are needed to ensure the financial survival even during bad times. Using the RAROC methodology we provide a new framework to quantify risks related to wholesale electricity contracts, also called full load contracts. We do not only consider risk of market price fluctuations but also correlation effects between the spot market price and the load curve of a customer. We further conduct an empirical study on whole sale contracts for industry customers and public utility companies of a German energy provider. Our findings support the adequateness of the approach and point out the importance of considering also price-volume correlation effects for electricity whole sale contracts.

We study on-line learning in the linear regression framework. Most of the performance bounds for on-line algorithms in this framework assume a constant learning rate. To achieve these bounds the learning rate must be optimized based on a posteriori information. This information depends on the whole sequence of examples and thus it is not available to any strictly on-line algorithm. We introduce new techniques for adaptively tuning the learning rate as the data sequence is progressively revealed. Our techniques allow us to prove essentially the same bounds as if we knew the optimal learning rate in advance. Moreover, such techniques apply to a wide class of on-line algorithms, including p-norm algorithms for generalized linear regression and Weighted Majority for linear regression with absolute loss. Our adaptive tunings are radically different from previous techniques, such as the so-called doubling trick. Whereas the doubling trick restarts the on-line algorithm several times using a constant learning rate for each run, our methods save information by changing the value of the learning rate very smoothly. In fact, for Weighted Majority over a finite set of experts our analysis provides a better leading constant than the doubling trick. © 2002 Elsevier Science (USA) In each trial t the algorithm receives a vector x t =(x t, 1 , ..., x t, n ) ¥ [ − 1, +1] n and is asked to predict the value of an unknown label y t ¥ [ − 1, +1] associated with x t . The algorithm keeps a weight vector w t =(w t, 1 , ..., w t, n ) representing its current hypothesis. The vector w t is an n-dimensional probability vector. The algorithm's prediction at time t is the linear combination ŷ t =w t · x t ¥ [ − 1, +1]. After receiving the correct label y t , the algorithm incurs a loss l t = 1 2 |y t − ŷ t | ¥ [0, 1]. Finally, the algorithm updates the weights according to the rule w t+1, i =w t, i exp{ − g 1 2 |y t − x t, i |}/W t+1 , ADAPTIVE ON-LINE ALGORITHMS

The bacteriochlorophyll (Bchl) c content and organization was determined for Chlorobium (Cb.) tepidum chlorosomes, the light-harvesting complexes from green photosynthetic bacteria, using fluorescence correlation spectroscopy and atomic force microscopy. Single-chlorosome fluorescence data was analyzed in terms of the correlation of the fluorescence intensity with time. Using this technique, known as fluorescence correlation spectroscopy, chlorosomes were shown to have a hydrodynamic radius (Rh) of 25 6 3.2 nm. This technique was also used to determine the concentration of chlorosomes in a sample, and pigment extraction and quantitation was used to determine the molar concentration of Bchl c present. From these data, a number of ;215,000 6 80,000 Bchl c per chlorosome was determined. Homogeneity of the sample was further characterized by dynamic light scattering, giving a single population of particles with a hydrodynamic radius of 26.8 6 3.7 nm in the sample. Tapping-mode atomic force microscopy (TMAFM) was used to determine the x,y,z dimensions of chlorosomes present in the sample. The results of the TMAFM studies indicated that the average chlorosome dimensions for Cb. tepidum was 174 6 8.3 3 91.4 6 7.7 3 10.9 6 2.71 nm and an overall average volume 90,800 nm 3 for the chlorosomes was determined. The data collected from these experiments as well as a model for Bchl c aggregate dimensions was used to determine possible arrangements of Bchl c oligomers in the chlorosomes. The results obtained in this study have significant implications on chlorosome structure and architecture, and will allow a more thorough investigation of the energetics of photosynthetic light harvesting in green bacteria.

The aim of this paper is to investigate the computer usage among secondary school students in one of a secondary school in Malaysia according on hours spent using computers without activities connecting to internet and hours spent doing internet activities. Questionnaires were given to the students, and seventy secondary school students had participated. This study involves some normal activities such as to find out (i) the value and percentage of students who had computers and internet connections at homes, (ii) the venues of the students spent time using computers without activities connecting to internet, (iii) the venues of the students spent time doing internet activities. In addition, (iv) hours spent using computers without activities connecting to internet, and (v) hours spent doing internet activities are also studied. Besides that the gender analyses based on some basic activities that can be done with computer were also analyzed. This study utilized Descriptive Statistics and Independent t-Test for the analysis methods. As for the result although more than half of the students had computers in their homes, however only half from this figure had accessed to the Internet. Many of the students also liked to use the computer whether it was connected or not connected to the internet by going to the cyber café. In addition, the hours spent on using computer weekly by male and female students were also revealed, that in many basic activities, male students were more likely to spend their valuable hours significantly sitting in front of computers doing things compared to the female students.

Using seven waves of data, collected twice a year from the 8th through the 11th grades in a low-resource community in Cape Town, South Africa, we aimed to describe the developmental trends in three specific leisure experiences (leisure boredom, new leisure interests, and healthy leisure) and substance use (cigarettes, alcohol, and marijuana) behaviors and to investigate the ways in which changes in leisure experiences predict changes in substance use behaviors over time. Results indicated that adolescents’ substance use increased significantly across adolescence, but that leisure experiences remained fairly stable over time. We also found that adolescent leisure experiences predicted baseline substance use and that changes in leisure experiences predicted changes in substance use behaviors over time, with leisure boredom emerging as the most consistent and strongest predictor of alcohol, cigarette, and marijuana use. Implications for interventions that target time use and leisure ex...

The present work deals with the synthesis of NiO/SiO 2 nanocomposites fabricated by embedding nickel oxide particles, obtained from hexahydrated nickel nitrate (Ni(NO 3 ) 2 ·6H 2 O), in a silica matrix, through sol-gel method based on hydrolysis and condensation of tetraethyl orthosilicate (TEOS) alkoxide. Due to the various factors, e.g. pH, EtOH/TEOS/H 2 O ratio, Si/Ni ratio, etc., influencing the gelation time of the solutions, Taguchi robust design method of system optimization was used to determine the percent of contribution (% ) of each factor. It was found that the pH of the solutions had the most influence on the gelation time (68.76%) and the Si/Ni atomic ratio stood in second place (12.95%). It was illustrated that the molar ratio of EtOH/TEOS had the least influence on the gelation time.

This study examines the effects of cationic and anionic surfactants on the performance of surfactant-enhanced ultrafiltration process. In particular, the separated removal of lead and arsenic from wastewater is investigated by using dodecylbenzenesulfonic acid (DSA) as anionic surfactant and dodecylamine as cationic surfactant. The ultrafiltration process is performed by means of a monotubular ceramic membrane of nominal pore size 20 nm (molecular weight cut-off: 210 kDa). Pb and As ions are removed from the water flow one at a time using both DSA and dodecylamine. Metals and surfactants are added in a biologically treated wastewater from a municipal wastewater treatment plant and then ultrafiltered. Concentrations of lead and arsenic introduced in the water vary from 4.4 to 7.6 mg/l, while DSA and dodecylamine concentrations are equal to 10 !5 M and 10 !6 M, respectively, both of them below their critical micelle concentration. The results show a quantitative removal of lead ions >99% in the Pb/DSA and Pb/dodecylamine systems, while it was observed a decrease of arsenate ions in both of systems of about 19%. The almost complete retention of lead cannot be due only to surfactants, but also to its bioabsorption by the abundant organic matter present in solution, while AsO 4 ions, being very toxic, are not adsorbed by microorganisms, therefore the removal is very low. The rejection of other main constituents found in wastewaters is already presented.

the authors examined 4 categories: emotional awareness-insight, relationship-climate, other-versus self-focus, and problem identification-change. The sample consisted of 64 10-year-old boys and girls, in all-female or mixed-gender groups (n ϭ 10). Results indicated that group relationship-climate was the therapeutic factor most frequently mentioned by the children and that problem identification-change was least appreciated. One difference was found between boys and girls, and one between all-female and mixed-gender groups. The discussion focuses on the importance and meaning of relationship-climate for children in group therapy.

Today web servers are ubiquitous having become critical infrastructures of many organizations. However, they are still one of the most vulnerable parts of organizations infrastructure. Exploits are many times used by worms to fast propagate across the full Internet being web servers one of their main targets. New exploit techniques have arouse in the last few years that have rendered useless traditional IDS techniques based on signature identification. Exploits use polymorphism (code encryption) and metamorphism (code obfuscation) to evade detection from signature-based IDSs. In this paper, we address precisely the topic of how to protect web servers against zero-day (new), polymorphic, and metamorphic malware embedded in data streams (requests) that target web servers. We rely on a novel technique to detect harmful binary code injection (i.e., exploits) in HTTP requests that is more efficient than current techniques based on binary code emulation or instrumentation of virtual engines. The detection of exploits is done through sandbox processes. The technique is complemented by another set of techniques such as caching, and pooling, to reduce its cost to neglectable levels. Our technique has little assumptions regarding the exploit unlike previous approaches that assume the existence of sled or getPC code, loops, read of the payload, writes to different addresses, etc. The evaluation shows that caching is highly effective and that the average latency introduced by our system is neglectable.

A new and direct procedure for the selective formation of para-iodotoluene from toluene is demonstrated for the first time using iodine monochloride (ICl) as the iodinating agent and zeolite H-beta as the catalyst. Zeolite H-beta and H.K-L are found to be more para-selective compared to other zeolite catalysts and the conventional catalysts, H2SO4 and SiO2. In the presence of a solvent (nitrobenzene) the conversion of ICl increases and the formation of side products (chlorotoluenes) decreases. The probable mechanism for the formation of iodotoluenes and some amount of chlorotoluenes involves the electrophilic attack of toluene by I+ and Cl+, respectively.

L'objectiu de la tesi doctoral es estudiar la importancia del temps com a factor de benestar quotidia en el context de la societat contemporania. Mes concretament, es proposa analitzar la creixent vinculacio del temps amb el benestar a partir de les relacions socials que s'estableixen entorn del treball. Quina es l'aportacio dels diferents temps de treball al benestar o que es percep socialment com a benestar son dos dels interrogants de partida. La perspectiva teorica proposada per abordar aquest objecte d'estudi pivota sobre tres eixos. En primer lloc, es proposa un canvi d'enfocament en la concepcio del benestar: un canvi que suposa el pas del benestar material al benestar quotidia, el pas d'una aproximacio macro a una aproximacio micro vers aquest concepte. Aquest canvi es caracteritza per l'ampliacio de la perspectiva economica i productivista que sovint s'utilitza per definir i mesurar el benestar. En aquest sentit, la tesi defensa l'us d&#3...

This paper presents a novel algorithm for computing graph edit distance (GED) in image categorization. This algorithm is purely structural, i.e., it needs only connectivity structure of the graph and does not draw on node or edge attributes. There are two major contributions: (1) Introducing edge direction histogram (EDH) to characterize shape features of images. It is shown that GED can be employed as distance of EDHs. This algorithm is completely independent on cost function which is difficult to be defined exactly.

The project itself, as well as key findings of Serbia Population Daily Time Use survey shall be presented in the following text. The author led the project in December, 2008, which was conducted by TNS Medium Gallup and Faculty for Culture and Media, Belgrade. This self-completion diary based survey comprised the sample of 1600 respondents, representing population of Serbia aged 12 and over. An average Serbian citizen spends 32% of his/her daily time sleeping, the survey reveals, 30% performing his/her everyday activities and duties (at work, housework, studying, personal care and meal), 19% is allocated to the media, 9% to leisure time (no media included), and 11% for other activities that cannot be grouped under any other previously mentioned category. Television takes 55% of the total amount of time devoted to the media, radio 24%, internet 11% and the press 9%. The major part of leisure time is allocated to visits by friends and vice versa (39%), 30% is time spent in pubs and clubs and 10% reading books. In addition to this, an average citizen spends 267.8 minutes per day communicating with other persons, directly, face to face or via any other means of modern technology. Direct active communication is 34.5% of the total communication, direct passive 43.7%, indirect active 9.6% and indirect passive 12.2%. This person feels particularly good and happy 178.4 minutes per day, and 44.3 minutes rather bad and unhappy. They fell good mainly thanks to their descendants (children and grandchildren) and female population, and bad due to job related roles and non-family relations.

This paper develops, tests, and discusses a metric for livelihood assessment that integrates cash flow and time use households. It expresses how much time the household adults have left after satisfying the household's basic needs (e.g., for food, sleep, care, consumables, and leisure). This "freely disposable time" (FDT) may be put to any use available and allowed in the local context, such as above-basic leisure, work to acquire above-basic consumer goods, or investments in the future such as education or soil conservation. Thus, FDT represents people's freedoms and a key condition for any out-of-poverty strategy. The FDT methodology is illustrated with a number of characteristic livelihood strategies and tested on peri-urban farming livelihoods in India and some typical Dutch households. The FDT outcomes, methodology, strengths, and limitations are compared with those of an allied, "Discretionary Time" indicator, paired time/money indicators and purely monetary (e.g., income or expenditure) indicators of poverty and welfare.

Burn-in and stress testing are becoming increasingly important, a sine qua non in the electronics industry as customers become increasingly sensitive to failures occurring in the useful life of a product or system. Burn-in subjects the product to expected field extremes by exposing the product to accelerated temperature and voltages stress to screen infant mortalities (latent failures). In the past, burn in duration studies use constant failure rate statistics to model the classical bathtub curve describing early-life failure behavior of the product throughout its operating lifetime. Thus, FIT (Failure in Time) rate calculations were greatly inflated by including failures occurring long after the time of interest. This manifests in a requirement for a very low failure rate after the conservative burn-in stresses causes the need to sample larger number of units in order to differentiate between the passing and failing criteria. Furthermore, it makes the Burn-In study more complicated and reduces the chance of success.

It is commonly believed that as people age and leave the labor force, they disengage from productive activity and become dependent. While consistent with the conventional economic view of what constitutes productive activity, this belief is inconsistent with a more contemporary view that unpaid work (domestic, volunteer, and caring work) is equally economically valuable (i.e., productive). We investigate differences in how people allocate time among productive and other activities pre-and post-retirement. Results indicate that people remain engaged in productive activities even as they move out of the labor force, substituting unpaid for paid work. Only respondents who have exceeded their normal life expectancy greatly reduce their productive activity. Evidence suggests a need to revisit assumptions underlying policy debate on population aging. Keywords Aging AE Productive activity AE Retirement AE Time use Economic policy is influenced by policy makers' perception of the productivity of the nation. Social and health policy is, in turn, shaped by perceptions both of the performance of the national economy (the ''size of the economic pie'' (Hicks, 2002, p. 24)) and of the productivity of individuals in society. Definitions of productivity can have a profound effect on how big a slice of the economic pie one is served. Productive activity typically is defined in the economics discipline as that which ''add[s] to the stock and flow of valued goods and services'' traded in the marketplace (Herzog, Kahn, Morgan, Jackson, & Antonucci, 1989, p. S129). Under this definition, labor market participation is a key marker of an individual's productivity. This perspective is D. Dosman (&) AE J. Fast AE S. A

Slaap. Hoewel slapen en sluimeren belangrijk aspecten waren van het dagdagelijkse leven in vroegmodern Europa, weten we er omzeggens niets over. Diverse cruciale vragen (zie hieronder) blijven daarbij onbeantwoord. Roger Ekirch is zowat de enige onderzoeker die over het onderwerp letterlijk artikelen en boeken vol heeft geschreven, hoewel het thema nu ook zijdelings tussen andere onderwerpen opduikt. Door enkele van Ekirch’s uitgangspunten nog eens kritisch onder de loep te nemen – pre-industriële mensen sliepen langer, maar minder continu, tot de opkomst van artificieel licht onze slaapcultuur voorgoed veranderde – willen we het debat weer aanwakkeren. Door in te zoomen op een lokaal bronnentype (namelijk juridische verslagen) kunnen we meteen ook de publieke belangstelling voor die lokale archieven weer een duwtje in de rug geven. Het zijn immers onvermoede schatkamers om het dagelijks leven in het verleden te reconstrueren.

Background: Some small controlled studies have found that dawn simulation is effective in treating seasonal affective disorder (SAD). With a larger sample size and a longer duration of treatment, we compared dawn simulation with bright light therapy and a placebo condition in patients with SAD. Method: Medication-free patients with SAD were randomly assigned to one of three conditions: bright light therapy (10,000 lux for 30 min, from 6:00 AM to 6:30 AM), dawn simulation (1.5 hour dawn signal from 4:30 AM to 6:00 AM peaking at 250 lux), and a placebo condition, a dim red light (1.5 hour dawn signal from 4:30 AM to 6:00 AM peaking at 0.5 lux.) Over the subsequent 6 weeks, the subjects were blindly rated by a psychiatrist using the Structured Interview Guide for the Hamilton Depression Rating-Seasonal Affective Disorder Version (SIGH-SAD). We modeled the profiles of the remissions (SIGH-SAD Յ 8) and response (Ն50% decrease in SIGH-SAD) to treatment over time using Cox proportional hazards models. Results: The sample consisted of 95 subjects who were randomized to the three conditions: bright light (n ϭ 33), dawn simulation (n ϭ 31) and placebo (n ϭ 31). Dawn simulation was associated with greater remission (p Ͻ .05) and response (p Ͻ .001) rates compared to the placebo. Bright light did not differ significantly from the placebo. Dawn simulation was associated with greater remission (p Ͻ .01) and response (p Ͻ .001) rates compared to the bright light therapy. The mean daily hours of sunshine during the week before each visit were associated with a significant increase in likelihood of both remission (p Ͻ .001) and response (p Ͻ .001). Conclusions: Dawn simulation was associated with greater remission and response rates compared to the placebo and compared to bright light therapy. The hours of sunshine during the week before each assessment were associated with a positive clinical response. Biol Psychi-atry 2001;50:205-216

We consider the problem of simultaneous bitrate allocation for multiple video streams. Current methods for multiplexing video streams often rely on identifying the relative complexity of the video streams to improve the combined overall quality. In such methods, not all the videos benefit from the multiplexing process. Typically, the quality of high motion videos is improved at the expense of a reduction in the quality of low motion videos. In our approach, we use a competitive equilibrium allocation of bitrate to simultaneously improve the quality of all the video streams by finding trades between videos across time. A central controller collects rate-distortion information from each video user and makes a joint bitrate allocation decision. Each user encodes and transmits his video at the allocated bitrate through a shared channel. The proposed method uses information about not only the differing complexity of the video streams at every moment but also the differing complexity of each stream over time. Using the competitive equilibrium bitrate allocation approach for multiple video streams, simulation results show that all the video streams perform better or at least as well as with individual encoding. The results of this research will be useful both for ad hoc networks that employ a cluster head model and for cellular architectures.

This study examines the effects of cationic and anionic surfactants on the performance of surfactant-enhanced ultrafiltration process. In particular, the separated removal of lead and arsenic from wastewater is investigated by using dodecylbenzenesulfonic acid (DSA) as anionic surfactant and dodecylamine as cationic surfactant. The ultrafiltration process is performed by means of a monotubular ceramic membrane of nominal pore size 20 nm (molecular weight cut-off: 210 kDa). Pb and As ions are removed from the water flow one at a time using both DSA and dodecylamine. Metals and surfactants are added in a biologically treated wastewater from a municipal wastewater treatment plant and then ultrafiltered. Concentrations of lead and arsenic introduced in the water vary from 4.4 to 7.6 mg/l, while DSA and dodecylamine concentrations are equal to 10 !5 M and 10 !6 M, respectively, both of them below their critical micelle concentration. The results show a quantitative removal of lead ions >99% in the Pb/DSA and Pb/dodecylamine systems, while it was observed a decrease of arsenate ions in both of systems of about 19%. The almost complete retention of lead cannot be due only to surfactants, but also to its bioabsorption by the abundant organic matter present in solution, while AsO 4 ions, being very toxic, are not adsorbed by microorganisms, therefore the removal is very low. The rejection of other main constituents found in wastewaters is already presented.

Real-time systems are often designed using a set of periodic tasks. Task periods are usually set by the system requirements, but deadlines and computation times can be modified in order to improve system performance. Sensitivity analysis in real-time systems has focused on changes in task computation times, using fixed priority analysis. Only a few studies deal with the modification of deadlines in dynamic-priority scheduling. The aim of this work is to provide a sensitivity analysis for task deadlines in the context of dynamic-priority, pre-emptive, uniprocessor scheduling. In this paper, we present a deadline minimisation method that computes the shortest deadline of a periodic task. As undertaken in other studies concerning computation times, we also define and calculate the critical scaling factor for task deadlines. Our proposal is evaluated and compared with other works. The deadline minimisation proposed strongly reduces jitter and response time of control tasks, which can lead to a significant improvement of the system performance.

In this paper, we present a new strongly polynomial time algorithm for the minimum cost flow problem, based on a refinement of the Edmonds-Karp scaling technique. Our algorithm solves the uncapacitated minimum cost flow problem as a sequence of O(n log n) shortest path problems on networks with n nodes and m arcs and runs in O(n log n (m + n log n)) time. Using a standard transformation, thjis approach yields an O(m log n (m + n log n)) algorithm for the capacitated minimum cost flow problem. This algorithm improves the best previous strongly polynomial time algorithm, due to Z. Galil and E. Tardos, by a factor of n 2 /m. Our algorithm for the capacitated minimum cost flow problem is even more efficient if the number of arcs with finite upper bounds, say n', is much less than m. In this case, the running time of the algorithm is O((m' + n)log n(m + n log n)).

This study assessed the sensitivity of the amphipod Chaetocorophium ef. lucasi, an inhabitant of New Zealand estuarine muddy sediments, and of the bivalve Macomona liliana, commonly found in New Zealand sandflats, to sediment particle-size distribution, total organic carbon, total organic nitrogen and water content. Growth and survival were evaluated after different test exposure times using laboratory-prepared natural sediment mixtures of sand and mud. The results suggest that amphipod survival was affected by the type of sand more than by the concentration of sand in the sediment samples. In samples with high survival rates, amphipod growth was impaired in sediments with higher sand proportions after a 10-day exposure, but after longer periods (28 or 30 days) there were no significant differences among treatments which had <76% sand. Bivalve survival and growth were not significantly affected by different natural sediment characteristics. Test duration for chronic toxicity tests with the bivalve M.////aria and the amphipod C. cf. lucasi should be at least 28 days for the detection of significant growth relative to the initial size.

The musical group the Beatles had a profound impact on Western culture during their time together between 1960 and 1970. The three songwriters, John Lennon, Paul McCartney, and George Harrison, together and separately evolved in their lyrical styles over time. Using a new generation of computer text analyses, the Beatles' lyrics were analyzed to address how the group changed as a unit over time, how the various members changed in their writing styles, and the overlap in lyrical styles from one composer to the next. Overall, the Beatles' lyrics became darker, more psychologically distant, and less immediate over time. Paul McCartney's lyrical style proved to be more variable and broad ranging than either Lennon or Harrison. Using latent semantic analyses, Harrison's lyrics were more influenced by Lennon than by McCartney. Finally, the lyrics jointly written by Lennon and McCartney were mathematically more similar to Lennon's linguistic styles than McCartney's.

In this article I bring artistic production into the learning sciences conversation by using the production of representations as a bridging concept between art making and the new literacies. Through case studies with 4 youth media arts organizations across the United States I ask how organizations structure the process of producing autobiographical digital art through a focus on representational tasks and how learning can be traced by examining youth artists' representations over time. Using a distributed cognition framework I analyze data on the process of making digital art in terms of the macro and micro tasks performed in order to identify occasions for external representation construction and use across organizations. I then examine how individual youth engage in these macro and micro tasks by producing representations that demonstrate their understanding. These analyses show that youth media arts organization production processes engage young artists in a representational trajectory that begins with developing a story about the self, moves toward a focus on how the tools of the medium afford representation of that story, and culminates in digital representations that reflect an understanding of the relationship between story and tools.

Laird No. 1 lentils micronized (high-intensity infrared heat) to give internal temperatures of 138 and 170 °C were compared to unprocessed lentils stored at room temperature. Micronized lentils, which had been tempered to 33% moisture for 16 h, required less force to compress after cooking and contained increased levels of gelatinized starch and pectic substances but decreased levels of soluble protein, phytic acid, and neutral detergent fiber compared to the unprocessed lentils. Cell walls in the micronized lentil were less susceptible to fracture, and the microstructure was more open. Properties of the micronized lentils were better when the internal temperature reached 138 °C. When micronized to an internal temperature of 170 °C, cooked lentils were harder, possibly due to greater moisture losses and a change in the neutral detergent fiber. Micronization resulted in a slight darkening of the lentils, and this was accentuated at 170 °C.

Studies suggest that children's housework contributions are minimal. However, much of this research focuses on young or early adolescent children and utilizes data regarding adult tasks, while ignoring chores children more often perform. We address these gaps by analyzing longitudinal time-use data collected from teens on the types of household chores that children are most likely to perform. Specifically, we examine gender inequity in teens' contributions to household labor and how it changes over high school. Additionally, we explore how teens' household contributions vary based on family structure characteristics such as maternal employment and parental marital status, and as a function of teens' involvement in such nonfamily contexts as school and paid work. We find that girls devote more time to household tasks than boys with this gender gap increasing across high school. Teens' efforts are greater in larger families, especially for girls, and those headed by single or remarried parents. Lastly, high school males spend more time on extra-curricular and leisure activities than girls who work longer hours in both unpaid and paid labor. Thus, we conclude that the leisure gap and the "second shift" documented between wives and husbands , may originate in the family of orientation.

Water table across much of the western Victoria, Australia have been declining for at least the last 10-15 years, and this is attributed to the consistently low rainfall for these years, but over the same period of time there has been substantial change in land use, with grazing land replaced by cropping and tree plantations appearing in some areas. Hence,

This article highlights a time-geographic approach to understanding the temporal patterns of people's occupations and their relationship to health and illness. It outlines the use of diaries to gather data and proposes that this method makes it possible to study the everyday life context of individuals, capturing i) Activity contexts (everyday context and project context) ii) Geographic context iii) Social context and iv) Experiential context. The method has been used to gather information about activity patterns in everyday life, and further developed to identify health risks in a population and as a foundation for intervention in rehabilitation. Examples described are application of the method to promote change processes in a workplace and in a rehabilitation setting.

Specification tests using stochastic bottleneck models of airport congestion investigate whether dominant airlines internalize or ignore self-imposed delays at twenty-seven major US airports. Data on flight times determine the airport's landing and takeoff delays for every minute of operation during peak travel days. Dynamic congestion functions based on stochastic-queuing theory separately identify delays that aircraft experience directly, impose internally on their airline's other aircraft, or impose externally on other airlines. Specification tests largely reject internalization and fail to reject non-internalization by dominant airlines. Optimal pricing should value all time using non-dominant aircraft time values and treat all delays as external.

The reactions of Cl atoms with a series of unsaturated aldehydes have been investigated for the first time using a relative method. In order to obtain additional information for a qualitative structure versus reactivity discussion, we have also determined the rate coefficients for the reactions of atomic chlorine with their respective saturated aldehydes. These relative measurements were performed at room temperature and atmospheric pressure of air and N 2 , by using ethane, propene and 1-butene as reference compounds. The weighted average relative rate constants obtained, k Cl ±2σ (in units of cm 3 molecule −1 s −1 ) were: trans-2-pentenal (1.31±0.19)×10 −10 ; trans-2-hexenal (1.92±0.22)×10 −10 ; trans-2-heptenal (2.40±0.29)×10 −10 ; n-pentanal (2.56±0.27)×10 −10 ; n-hexanal (2.88±0.37)×10 −10 ; n-heptanal (3.00±0.34)×10 −10 .

This article introduces an effective job analysis method for examining how people spend their working time, that is, the tasks they perform, the time each accounts for, and how they perceive these. Based on the principles of work sampling, it addresses several disadvantages of existing techniques. Self-report data are collected using mini portable computers (personal digital assistants; PDAs), the efficiency of which enables a more comprehensive approach to be adopted. A key feature of the method is the use of multilevel categories to examine work tasks from multiple perspectives, simultaneously, in a detailed manner. The article describes the development of the method, illustrates its procedures and analyses using sample research data, and evaluates its use as an organizational research tool. Furthermore, it provides detailed and accessible descriptions of the numerous methodological and technical procedures common to all work sampling approaches, and discusses the various associated issues.