Structural and photonic properties of opal-GaN nanocomposites

Electron microscopic methods have been applied to demonstrate that gallium nitride synthesized in opal voids has perfect crystal structure. Studies of optical reflection spectra revealed that the obtained opal-〈gallium nitride〉 nanocomposites retain the photonic-crystal properties of the ordered host matrix at any (0–100%) degree of opal void filling with gallium nitride.     

The utility of Stroop task switching as a marker for early-stage Alzheimer's disease.

[Correction Notice: An erratum for this article was reported in Vol 25(4) of Psychology and Aging (see record 2010-22172-001). Author Janet M. Duchek’s name was misspelled as Janet M. Ducheck. The online version has been corrected.] Past studies have suggested attentional control tasks such as the Stroop task and the task-switching paradigm may be sensitive for the early detection of dementia of the Alzheimer's type (DAT). The authors of the current study combined these tasks to create a Stroop switching task. Performance was compared across young adults, older adults, and individuals diagnosed with very mild dementia. Results indicated that this task strongly discriminated individuals with healthy aging from those with early-stage DAT. In a logistic regression analysis, incongruent error rates from the Stroop switching task discriminated healthy aging from DAT better than any of the other 18 cognitive tasks given in a psychometric battery. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Correction to Hutchison, Balota, and Duchek (2010).

Reports an error in "The utility of Stroop task switching as a marker for early-stage Alzheimer's disease" by Keith A. Hutchison, David A. Balota and Janet M. Ducheck (Psychology and Aging, 2010[Sep], Vol 25[3], 545-559). Author Janet M. Duchek’s name was misspelled as Janet M. Ducheck. The online version has been corrected. (The following abstract of the original article appeared in record 2010-18944-003.) Past studies have suggested attentional control tasks such as the Stroop task and the task-switching paradigm may be sensitive for the early detection of dementia of the Alzheimer's type (DAT). The authors of the current study combined these tasks to create a Stroop switching task. Performance was compared across young adults, older adults, and individuals diagnosed with very mild dementia. Results indicated that this task strongly discriminated individuals with healthy aging from those with early-stage DAT. In a logistic regression analysis, incongruent error rates from the Stroop switching task discriminated healthy aging from DAT better than any of the other 18 cognitive tasks given in a psychometric battery. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Use of sexed semen and its effect on conception rate, calf sex, dystocia, and stillbirth of Holsteins in the United States

Use of sexed semen for artificial insemination of US Holstein heifers (1.3 million breedings) and cows (10.8 million breedings) in Dairy Herd Improvement herds was characterized by breeding year, parity, service number, region, herd size, and herd milk yield. Sexed semen was used for 1.4, 9.5, and 17.8% of all reported breedings for 2006, 2007, and 2008, respectively, for heifers, and for 0.1, 0.2, and 0.4%, respectively, for cows. For 2008 sexed semen breedings, 80.5 and 68.6% of use was for first services of heifers and cows, respectively. For cows, 63.1% of 2008 sexed semen use was for first parity. Mean sexed semen use within herd was the greatest for heifers in the Southwest (36.2%) and for cows in the Mideast (1.3%). Mean sexed semen use increased for heifers but changed little for cows as either herd size or herd mean milk yield increased. Availability of sexed semen was examined for Holstein bulls in active AI service; of 700 bulls born after 1993, 37% had sexed semen marketed by mid August 2009. Active AI bulls with marketed sexed semen were superior to average active AI bulls for evaluations of yield traits, productive life, somatic cell score, daughter pregnancy rate, service-sire calving ease, service-sire stillbirth, final score, sire conception rate, and lifetime net merit. The effect of sexed semen use on conception rate, calf sex, dystocia, and stillbirth also was examined for heifers and cows. Mean conception rate for heifers was 56% for conventional and 39% for sexed semen; corresponding conception rates for cows were 30 and 25%. For single births from sexed semen breedings, around 90% were female. Dystocia and stillbirth were more frequent for heifers (6.0 and 10.4%, respectively, for conventional semen; 4.3 and 11.3%, respectively, for sexed semen) than for cows (2.5 and 3.6%, respectively, for conventional semen; 0.9 and 2.7%, respectively, for sexed semen). Difficult births declined by 28% for heifers and 64% for cows with sexed semen use. Stillbirths were more prevalent for twin births except for sexed semen heifer breedings. Stillbirths of single male calves of heifers were more frequent for breedings with sexed semen (15.6%) than conventional semen (10.8%); a comparable difference was not observed for cows, for which stillbirth frequency of single male calves even decreased (2.6 vs. 3.6%). Overall stillbirth frequency was reduced by sexed semen use for cows but not for heifers.     

The use of global synthetic data for pre-launch tuning of the VIIRS cloud mask algorithm

A methodology is presented to perform pre-launch tuning of thresholds used in the Visible Infrared Imager/Radiometer Suite (VIIRS) cloud mask (VCM) algorithm. The approach relies upon several data sources, including global synthetic data (GSD), Moderate Resolution Imaging Spectroradiometer (MODIS) and VIIRS relative spectral responses (RSRs) and MODIS top-of-atmosphere (TOA) radiance, reflectance and brightness temperature data. The GSD are used first to derive cloud cover distributions, that is, 0%, 50% and 100%, at VIIRS moderate resolution (800 m) for each VCM cloud detection test, based on inputs to the radiative transfer models. These cloud distributions are then used to update the values of the low, mid and high cloud-free confidence thresholds in the VCM algorithm. The approach is demonstrated by using MODIS RSRs with the GSD to set these thresholds and then analysing granules of MODIS data with the updated VCM. Performance is quantified through comparisons with manually generated cloud masks created from the MODIS imagery. The performance of the tuned VCM with MODIS data improved substantially for all major background conditions. The probability of correct typing (PCT) improved nearly 4% over the ocean to 97.5% and nearly 20% over snow-covered surfaces to 95.1%. The PCT values over land improved from 87.1% to 93.4% and over desert from 87.2% to 93.9%. The process was then repeated using VIIRS RSRs and the updated thresholds were forwarded to the National Polar-Orbiting Operational Satellite System (NPOESS) Preparatory Project (NPP) ground segment for incorporation into the operational system. It is concluded that GSD are invaluable for the pre-launch tuning of the VCM algorithm, which is now expected to exceed system requirements soon after the launch of the NPP satellite.     

Automated cloud detection and classification of data collected by the Visible Infrared Imager Radiometer Suite (VIIRS)

The Visible Infrared Imager Radiometer Suite (VIIRS) is a high‐resolution Earth imager of the United States National Polar‐orbiting Operational Environmental Satellite System (NPOESS). VIIRS has its heritage in three sensors currently collecting imagery of the Earth—the Advanced Very High Resolution Radiometer, the Moderate Resolution Imaging Spectroradiometer, and the Operational Linescan Sensor. The first launch of the VIIRS sensor is on NASA's NPOESS Preparatory Project (NPP). Data collected by VIIRS will provide products to a variety of users, supporting applications from real‐time to long‐term climate change timescales. VIIRS has been uniquely designed to satisfy this full range of requirements. Cloud masks derived from the automated analyses of VIIRS data are critical data products for the NPOESS program. In this paper, the VIIRS cloud mask (VCM) performance requirements are highlighted, along with the algorithm developed to satisfy these requirements. The expected performance of the VCM algorithm is established using global synthetic cloud simulations and manual cloud analyses of VIIRS proxy imagery. These results show the VCM analyses will satisfy the performance expectations of products created from it, including land and ocean surface products, cloud microphysical products, and automated cloud forecast products. Finally, minor deficiencies that remain in the VCM algorithm logic are identified along with a mitigation plan to resolve each prior to NPP launch or shortly thereafter.     

Filters: QoS support mechanisms for multipeer communications

The nature of distributed multimedia applications is such that they require multipeer communication support mechanisms. The multimedia traffic needs to be delivered to end-systems, networks, and end-users in a form that they can handle while satisfying the constraints imposed by the multimedia application. Quality-of-service (QoS) mechanisms that can ensure full quality media playout at high-performance workstations, while at the same time providing appropriately filtered lower quality media for playout at other end-systems, are required. Existing multicast support mechanisms are deficient for this purpose, in a heterogeneous environment, because they work on a common denominator premise where the quality delivered depends on the least capable link or node involved in the multicast session. This paper begins by discussing video compression; it proposes and analyzes the use of filtering mechanisms as means of supporting disparate receiver capabilities and QoS requirements. The paper describes the implementation of a number of filtering mechanisms and highlights the communications architecture within which these mechanisms are built. This architecture constitutes a specific network topology and a new protocol family developed within a UNIX-like operating system