449 research outputs found
Bio-logging science: sensing beyond the boundaries
Bio-logging has emerged as a tool in animal biology much as genomics has emerged as a tool in the study of cellular and organ function. Bio-logging is certain to increase in its importance and to influence the way we study events and processes that are beyond the usual boundaries of perception and that are remote from the observer. It is providing insights into the behaviour and function of organisms in environments that are hostile to the observer and in natural situations. In terms of the way that data are collected it has much in common with remote sensing and Earth observation. This includes post hoc analysis and interpretation of extensive data sets involving a low diversity of measured variables. Owing to the sparseness of data sets, practitioners need to develop better methods of applying the data to models of the organisms being studied. Although increasing technological sophistication is leading to collection of a greater diversity of variables, this also brings complications of interpreting multi-dimension data sets. Although it appears that technology currently constrains the type of biological questions that can be addressed, there is a danger that technological advancement could result in a loss of focus on hypothesis testing. There is evidence that the discipline of bio-logging is developing a substructure within which specialist teams of modellers, theoretical and field biologists, and engineers collaborate to address complex biological questions
An inside view on pesticide policy
European governments are poised to ban neonicotinoid pesticides. Insights from six years as a senior government advisor have led me to conclude that agricultural reform is urgently needed, beyond cycles of pesticide licensing and withdrawal.PostprintPeer reviewe
Composition dependence of electronic structure and optical properties of Hf1-xSixOy gate dielectrics
Copyright © 2008 American Institute of Physics. This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditionsComposition-dependent electronic structure and optical properties of Hf1−xSixOy 0.1 x 0.6 gate
dielectrics on Si at 450 °C grown by UV-photo-induced chemical vapor deposition UV-CVD have
been investigated via x-ray photoemission spectroscopy and spectroscopy ellipsometry SE . By
means of the chemical shifts in the Hf 4f, Si 2p, and O 1s spectra, the Hf–O–Si bondings in the
as-deposited films have been confirmed. Analyses of composition-dependent band alignment of
Hf1−xSixOy / Si gate stacks have shown that the valence band VB offset Ev demonstrates little
change; however, the values of conduction band offset Ec increase with the increase in the silicon
atomic composition, resulting from the increase in the separation between oxygen 2p orbital VB
state and antibonding d states intermixed of Hf and Si. Analysis by SE, based on the Tauc–Lorentz
model, has indicated that decreases in the optical dielectric constant and increase in band gap have
been observed as a function of silicon contents. Changes in the complex dielectric functions and
band gap Eg related to the silicon concentration in the films are discussed systematically. From the
band offset and band gap viewpoint, these results suggest that Hf1−xSixOy films provide sufficient
tunneling barriers for electrons and holes, making them promising candidates as alternative gate
dielectrics.National Natural Science Foundation of China and Royal Society U.K
Entanglement quantification from incomplete measurements: Applications using photon-number-resolving weak homodyne detectors
The certificate of success for a number of important quantum information
processing protocols, such as entanglement distillation, is based on the
difference in the entanglement content of the quantum states before and after
the protocol. In such cases, effective bounds need to be placed on the
entanglement of non-local states consistent with statistics obtained from local
measurements. In this work, we study numerically the ability of a novel type of
homodyne detector which combines phase sensitivity and photon-number resolution
to set accurate bounds on the entanglement content of two-mode quadrature
squeezed states without the need for full state tomography. We show that it is
possible to set tight lower bounds on the entanglement of a family of two-mode
degaussified states using only a few measurements. This presents a significant
improvement over the resource requirements for the experimental demonstration
of continuous-variable entanglement distillation, which traditionally relies on
full quantum state tomography.Comment: 18 pages, 6 figure
An International Quiet Ocean Experiment
Author Posting. © Oceanography Society, 2011. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 24, no. 2 (2011): 174–181, doi:10.5670/oceanog.2011.37.The effect of noise on marine life is one of the big unknowns of current marine science. Considerable evidence exists that the human contribution to ocean noise has increased during the past few decades: human noise has become the dominant component of marine noise in some regions, and noise is directly correlated with the increasing industrialization of the ocean. Sound is an important factor in the lives of many marine organisms, and theory and increasing observations suggest that human noise could be approaching levels at which negative effects on marine life may be occurring. Certain species already show symptoms of the effects of sound. Although some of these effects are acute and rare, chronic sublethal effects may be more prevalent, but are difficult to measure. We need to identify the thresholds of such effects for different species and be in a position to predict how increasing anthropogenic sound will add to the effects. To achieve such predictive capabilities, the Scientific Committee on Oceanic Research (SCOR) and the Partnership for Observation of the Global Oceans (POGO) are developing an International Quiet Ocean Experiment (IQOE), with the objective of coordinating the international research community to both quantify the ocean soundscape and examine the functional relationship between sound and the viability of key marine organisms. SCOR and POGO will convene an open science meeting to gather community input on the important research, observations, and modeling activities that should be included in IQOE
Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. II: The Second Year (2009-2010)
As an extension of the project in Kato et al. (2009, arXiv:0905.1757), we
collected times of superhump maxima for 61 SU UMa-type dwarf novae mainly
observed during the 2009-2010 season. The newly obtained data confirmed the
basic findings reported in Kato et al. (2009): the presence of stages A-C, as
well as the predominance of positive period derivatives during stage B in
systems with superhump periods shorter than 0.07 d. There was a systematic
difference in period derivatives for systems with superhump periods longer than
0.075 d between this study and Kato et al. (2009). We suggest that this
difference is possibly caused by the relative lack of frequently outbursting SU
UMa-type dwarf novae in this period regime in the present study. We recorded a
strong beat phenomenon during the 2009 superoutburst of IY UMa. The close
correlation between the beat period and superhump period suggests that the
changing angular velocity of the apsidal motion of the elliptical disk is
responsible for the variation of superhump periods. We also described three new
WZ Sge-type objects with established early superhumps and one with likely early
superhumps. We also suggest that two systems, VX For and EL UMa, are WZ
Sge-type dwarf novae with multiple rebrightenings. The O-C variation in OT
J213806.6+261957 suggests that the frequent absence of rebrightenings in very
short-Porb objects can be a result of sustained superoutburst plateau at the
epoch when usual SU UMa-type dwarf novae return to quiescence preceding a
rebrightening. We also present a formulation for a variety of Bayesian
extension to traditional period analyses.Comment: 63 pages, 77 figures, 1 appendix, Accepted for publication in PASJ,
data correctio
The association of mammographic density with ductal carcinoma in situ of the breast: the Multiethnic Cohort
INTRODUCTION: It is well established that women with high mammographic density are at greater risk for breast cancer than are women with low breast density. However, little research has been done on mammographic density and ductal carcinoma in situ (DCIS) of the breast, which is thought to be a precursor lesion to some invasive breast cancers. METHOD: We conducted a nested case-control study within the Multiethnic Cohort, and compared the mammographic densities of 482 patients with invasive breast cancer and 119 with breast DCIS cases versus those of 667 cancer-free control subjects. A reader blinded to disease status performed computer-assisted density assessment. For women with more than one mammogram, mean density values were computed. Polytomous logistic regression models were used to compute adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for two measurements of mammographic density: percentage density and dense area. RESULTS: Mammographic density was associated with invasive breast cancer and breast DCIS. For the highest category of percentage breast density (≥50%) as compared with the lowest (<10%), the OR was 3.58 (95% CI 2.26–5.66) for invasive breast cancer and 2.86 (1.38–5.94) for breast DCIS. Similarly, for the highest category of dense area (≥45 cm(2)) as compared with the lowest (<15 cm(2)), the OR was 2.92 (95% CI 2.01–4.25) for invasive breast cancer and 2.59 (1.39–4.82) for breast DCIS. Trend tests were significant for invasive breast cancer (P for trend < 0.0001) and breast DCIS (P for trend < 0.001) for both percentage density and dense area. CONCLUSION: The similar strength of association for mammographic density with breast DCIS and invasive breast cancer supports the hypothesis that both diseases may have a common etiology
Evaluating the effectiveness of a large multi-use MPA in protecting Key Biodiversity Areas for marine predators
Marine protected areas can serve to regulate harvesting and conserve biodiversity. Within large multi‐use MPAs, it is often unclear to what degree critical sites of biodiversity are afforded protection against commercial activities. Addressing this issue is a prerequisite if we are to appropriately assess sites against conservation targets. We evaluated whether the management regime of a large MPA conserved sites (Key Biodiversity Areas, KBAs) supporting the global persistence of top marine predators
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