Recently, scalable video codecs based upon motion compensated temporal filtering (MCTF) have rece... more Recently, scalable video codecs based upon motion compensated temporal filtering (MCTF) have received a lot of attention. These video coding schemes perform on par with H.264, the current state-of-the-art video coding standard, while providing quality, resolution and frame-rate scalability. In this paper we aim to evaluate the rate-distortion performance of MCTF-based codecs when applied to volumetric data sets. In our experiments the lossy coding efficiency of an MCTF-based codec is compared to that of the 3D QT-L codec, which represents the state-of-the-art in volumetric coding. The results show that the MCTF-based coder does not provide better PSNR performance than the 3D QT-L codec. However, if the rate spent to code the motion vector information is not taken into account, the performance of the MCTF-based codec at low rates is on par or better than the performance of the 3D QT-L. This leads us to conclude that possible distortion improvements obtained by using MCTF instead of a regular wavelet-transform in the temporal direction do not outweigh the extra rate needed to encode the motion vector information.
Background-A rapidly growing number of long-QT syndrome (LQTS) patients are being treated with an... more Background-A rapidly growing number of long-QT syndrome (LQTS) patients are being treated with an implantable cardioverter-defibrillator (ICD). ICDs may pose problems, especially in the young. We sought to determine the characteristics of the LQTS patients receiving an ICD, the indications, and the aftermath. Methods and Results-The study population included 233 patients. Beginning in 2002, data were collected prospectively.
The QT interval (QT) is heritable and its prolongation is a risk factor for ventricular tachyarrh... more The QT interval (QT) is heritable and its prolongation is a risk factor for ventricular tachyarrhythmias and sudden death. Most genetic studies of QT have examined European ancestral populations; however, the increased genetic diversity in African Americans provides opportunities to narrow association signals and identify population-specific variants. We therefore evaluated 6,670 SNPs spanning eleven previously identified QT loci in 8,644 African American participants from two Population Architecture using Genomics and Epidemiology (PAGE) studies: the Atherosclerosis Risk in Communities study and Women's Health Initiative Clinical Trial. Of the fifteen known independent QT variants at the eleven previously identified loci, six were significantly associated with QT in African American populations (P#1.20610 24 ): ATP1B1, PLN1, KCNQ1, NDRG4, and two NOS1AP independent signals. We also identified three population-specific signals significantly associated with QT in African Americans (P#1.37610 25 ): one at NOS1AP and two at ATP1B1. Linkage disequilibrium (LD) patterns in African Americans assisted in narrowing the region likely to contain the functional variants for several loci. For example, African American LD patterns showed that 0 SNPs were in LD with NOS1AP signal rs12143842, compared with European LD patterns that indicated 87 SNPs, which spanned 114.2 Kb, were in LD with rs12143842. Finally, bioinformaticbased characterization of the nine African American signals pointed to functional candidates located exclusively within non-coding regions, including predicted binding sites for transcription factors such as TBX5, which has been implicated in cardiac structure and conductance. In this detailed evaluation of QT loci, we identified several African Americans SNPs that better define the association with QT and successfully narrowed intervals surrounding established loci. These results demonstrate that the same loci influence variation in QT across multiple populations, that novel signals exist in African Americans, and that the SNPs identified as strong candidates for functional evaluation implicate gene regulatory dysfunction in QT prolongation.
Recently, scalable video codecs based upon motion compensated temporal filtering (MCTF) have rece... more Recently, scalable video codecs based upon motion compensated temporal filtering (MCTF) have received a lot of attention. These video coding schemes perform on par with H.264, the current state-of-the-art video coding standard, while providing quality, resolution and frame-rate scalability. In this paper we aim to evaluate the rate-distortion performance of MCTF-based codecs when applied to volumetric data sets. In our experiments the lossy coding efficiency of an MCTF-based codec is compared to that of the 3D QT-L codec, which represents the state-of-the-art in volumetric coding. The results show that the MCTF-based coder does not provide better PSNR performance than the 3D QT-L codec. However, if the rate spent to code the motion vector information is not taken into account, the performance of the MCTF-based codec at low rates is on par or better than the performance of the 3D QT-L. This leads us to conclude that possible distortion improvements obtained by using MCTF instead of a regular wavelet-transform in the temporal direction do not outweigh the extra rate needed to encode the motion vector information.
Background-A rapidly growing number of long-QT syndrome (LQTS) patients are being treated with an... more Background-A rapidly growing number of long-QT syndrome (LQTS) patients are being treated with an implantable cardioverter-defibrillator (ICD). ICDs may pose problems, especially in the young. We sought to determine the characteristics of the LQTS patients receiving an ICD, the indications, and the aftermath. Methods and Results-The study population included 233 patients. Beginning in 2002, data were collected prospectively.
The QT interval (QT) is heritable and its prolongation is a risk factor for ventricular tachyarrh... more The QT interval (QT) is heritable and its prolongation is a risk factor for ventricular tachyarrhythmias and sudden death. Most genetic studies of QT have examined European ancestral populations; however, the increased genetic diversity in African Americans provides opportunities to narrow association signals and identify population-specific variants. We therefore evaluated 6,670 SNPs spanning eleven previously identified QT loci in 8,644 African American participants from two Population Architecture using Genomics and Epidemiology (PAGE) studies: the Atherosclerosis Risk in Communities study and Women's Health Initiative Clinical Trial. Of the fifteen known independent QT variants at the eleven previously identified loci, six were significantly associated with QT in African American populations (P#1.20610 24 ): ATP1B1, PLN1, KCNQ1, NDRG4, and two NOS1AP independent signals. We also identified three population-specific signals significantly associated with QT in African Americans (P#1.37610 25 ): one at NOS1AP and two at ATP1B1. Linkage disequilibrium (LD) patterns in African Americans assisted in narrowing the region likely to contain the functional variants for several loci. For example, African American LD patterns showed that 0 SNPs were in LD with NOS1AP signal rs12143842, compared with European LD patterns that indicated 87 SNPs, which spanned 114.2 Kb, were in LD with rs12143842. Finally, bioinformaticbased characterization of the nine African American signals pointed to functional candidates located exclusively within non-coding regions, including predicted binding sites for transcription factors such as TBX5, which has been implicated in cardiac structure and conductance. In this detailed evaluation of QT loci, we identified several African Americans SNPs that better define the association with QT and successfully narrowed intervals surrounding established loci. These results demonstrate that the same loci influence variation in QT across multiple populations, that novel signals exist in African Americans, and that the SNPs identified as strong candidates for functional evaluation implicate gene regulatory dysfunction in QT prolongation.
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