Time-Efficient Read/Write Register in Crash-prone Asynchronous Message-Passing Systems

The atomic register is certainly the most basic object of computing science. Its implementation on top of an n-process asynchronous message-passing system has received a lot of attention. It has been shown that t \textless{} n/2 (where t is the maximal number of processes that may crash) is a necessary and sufficient requirement to build an atomic register on top of a crash-prone asynchronous message-passing system. Considering such a context, this paper visits the notion of a fast implementation of an atomic register, and presents a new time-efficient asynchronous algorithm. Its time-efficiency is measured according to two different underlying synchrony assumptions. Whatever this assumption, a write operation always costs a round-trip delay, while a read operation costs always a round-trip delay in favorable circumstances (intuitively, when it is not concurrent with a write). When designing this algorithm, the design spirit was to be as close as possible to the one of the famous ABD algorithm (proposed by Attiya, Bar-Noy, and Dolev)

Rotation and Spin in Physics

We delineate the role of rotation and spin in physics, discussing in order Newtonian classical physics, special relativity, quantum mechanics, quantum electrodynamics and general relativity. In the latter case, we discuss the generalization of the Kepler formula to post-Newtonian order $(c^{-2}$) including spin effects and two-body effects. Experiments which verify the theoretical results for general relativistic spin-orbit effects are discussed as well as efforts being made to verify the spin-spin effects

Risk perceptions starting to shift? U.S. citizens are forming opinions about nanotechnology

This article presents early results from an opinion formation study based on a 76-member panel of U.S. citizens, with comparison data from a group of 177 nanotechnology experts. While initially similar to the expert group in terms of their perceptions of the risks, benefits, and need for regulation characterizing several forms of nanotechnology, the first follow-up survey indicates that the panel is beginning to diverge from the experts, particularly with respect to perceptions of the levels of various “societal” risks that nanotechnology might present. The data suggest that responding to public concerns may involve more than attention to physical risks in areas such as health and environment; concerns about other forms of risk actually appear more salient

Construct validation of a non-exercise measure of cardiorespiratory fitness in older adults

<p>Abstract</p> <p>Background</p> <p>Cardiorespiratory fitness (CRF) is associated with a decreased risk of all-cause mortality but is rarely assessed in medical settings due to burdens of time, cost, risk, and resources. The purpose of this study was to test the construct validity of a regression equation developed by Jurca and colleagues (2005) to estimate CRF without exercise testing in community dwelling older adults.</p> <p>Methods</p> <p>Participants (n = 172) aged 60 to 80 years with no contraindications to submaximal or maximal exercise testing completed a maximal graded exercise test (GXT) and the submaximal Rockport 1-mile walk test on separate occasions. Data included in the regression equation (age, sex, body mass index, resting heart rate, and physical activity) were obtained via measurement or self-report. Participants also reported presence of cardiovascular conditions.</p> <p>Results</p> <p>The multiple R for the regression equation was .72, <it>p < .001 </it>and CRF estimated from this equation was significantly correlated with the MET value from the GXT (<it>r </it>= 0.66) and with CRF estimated from submaximal field testing (<it>r </it>= 0.67). All three CRF indices were significantly and inversely associated with reporting more cardiovascular conditions.</p> <p>Conclusions</p> <p>This research provides preliminary evidence that a non-exercise estimate of CRF is at least as valid as field test estimates of CRF and represents a low-risk, low-cost, and expedient method for estimating fitness in older adults.</p

Secrecy capacity of a class of orthogonal relay eavesdropper channels

The secrecy capacity of relay channels with orthogonal components is studied in the presence of an additional passive eavesdropper node. The relay and destination receive signals from the source on two orthogonal channels such that the destination also receives transmissions from the relay on its channel. The eavesdropper can overhear either one or both of the orthogonal channels. Inner and outer bounds on the secrecy capacity are developed for both the discrete memoryless and the Gaussian channel models. For the discrete memoryless case, the secrecy capacity is shown to be achieved by a partial decode-and-forward (PDF) scheme when the eavesdropper can overhear only one of the two orthogonal channels. Two new outer bounds are presented for the Gaussian model using recent capacity results for a Gaussian multi-antenna point-to-point channel with a multi-antenna eavesdropper. The outer bounds are shown to be tight for two sub-classes of channels. The first sub-class is one in which the source and relay are clustered and the and the eavesdropper receives signals only on the channel from the source and the relay to the destination, for which the PDF strategy is optimal. The second is a sub-class in which the source does not transmit to the relay, for which a noise-forwarding strategy is optimal.Comment: Submitted to Eurasip Journal on Wireless Communications and Networking special issue on Wireless physical layer security, Dec. 2008, Revised Jun. 200

Vitamin D during pregnancy: why observational studies suggest deficiency and interventional studies show no improvement in clinical outcomes? A narrative review

International audienc

Building Babies - Chapter 16

In contrast to birds, male mammals rarely help to raise the offspring. Of all mammals, only among rodents, carnivores, and primates, males are sometimes intensively engaged in providing infant care (Kleiman and Malcolm 1981). Male caretaking of infants has long been recognized in nonhuman primates (Itani 1959). Given that infant care behavior can have a positive effect on the infant’s development, growth, well-being, or survival, why are male mammals not more frequently involved in “building babies”? We begin the chapter defining a few relevant terms and introducing the theory and hypotheses that have historically addressed the evolution of paternal care. We then review empirical findings on male care among primate taxa, before focusing, in the final section, on our own work on paternal care in South American owl monkeys (Aotus spp.). We conclude the chapter with some suggestions for future studies.Deutsche Forschungsgemeinschaft (HU 1746/2-1) Wenner-Gren Foundation, the L.S.B. Leakey Foundation, the National Geographic Society, the National Science Foundation (BCS-0621020), the University of Pennsylvania Research Foundation, the Zoological Society of San Dieg

Review of the algal biology program within the National Alliance for Advanced Biofuels and Bioproducts

In 2010, when the National Alliance for Advanced Biofuels and Bioproducts (NAABB) consortium began, little was known about the molecular basis of algal biomass or oil production. Very few algal genome sequences were available and efforts to identify the best-producing wild species through bioprospecting approaches had largely stalled after the U.S. Department of Energy's Aquatic Species Program. This lack of knowledge included how reduced carbon was partitioned into storage products like triglycerides or starch and the role played by metabolite remodeling in the accumulation of energy-dense storage products. Furthermore, genetic transformation and metabolic engineering approaches to improve algal biomass and oil yields were in their infancy. Genome sequencing and transcriptional profiling were becoming less expensive, however; and the tools to annotate gene expression profiles under various growth and engineered conditions were just starting to be developed for algae. It was in this context that an integrated algal biology program was introduced in the NAABB to address the greatest constraints limiting algal biomass yield. This review describes the NAABB algal biology program, including hypotheses, research objectives, and strategies to move algal biology research into the twenty-first century and to realize the greatest potential of algae biomass systems to produce biofuels