bluuebunny/crossref_metadata_2025 huggingface dataset:
High school science teachers' views of standards and accountability
Authors: Donnelly Lisa A. , Sadler Troy D.
Published: April 2009

Previous literature has documented how teachers perceive both advantages and disadvantages associated with standards‐based reform. These teacher perceptions may be connected to classroom practices in terms of the extent to which standards are utilized by individual teachers. The purpose of this study was to identify how secondary science teachers characterize state science standards, modify their curricula on the basis of standards, and view the impacts of standards on students and teachers in their schools. Twenty‐two science teachers from five purposefully selected school districts were interviewed using a protocol targeting attitudes toward standards and accountability, ways teachers use standards to develop and modify curricula, impacts of standards on students and teachers, and utilization of standards‐based resources and professional development. An inductive approach was used to analyze data and produced both common views of science standards held by many teachers and profiles that characterize subgroups of teachers. Participants described both positive and negative aspects of standards‐based accountability, and roughly half of the teachers described modifying their curricula according to standards. Teachers were categorized into six different profiles: negative perspectives, game of testing, already doing it, part of the cycle, reality of teaching, and useful tools. Suggestions for different approaches to professional development are elaborated for teachers of these various profiles. © 2009 Wiley Periodicals, Inc. Sci Ed 93:1050–1075, 2009
Has the US Cancer Centre model been ‘successful’? Lessons for the European cancer community
Authors: Sullivan Richard
Published: April 2009

The US model of Cancer Centres created by the National Cancer Act in 1971 has been one of the most tried and tested models of organised disease‐specific scientific endeavors in the world. With many countries, particularly those in Europe now looking to develop the research arms of their National Cancer Control Programmes through the development of similar Cancer Centres the time is correct to consider the success and limitations of the US effort to date. Here we described the salient features of both US Cancer Centres and Networks, including their funding and evaluation with socio‐political analysis on the learning points for Europe. In particular we highlight issues around sustainable funding, training and network development. New data highlighting deficiencies in the US model around prevention, health promotion, health inequalities in cancer outcomes, and clinical research provide key learning points and opportunities for the European model developed.
Breast-feeding and adherence to infant feeding guidelines do not influence bone mass at age 4 years
Authors: Harvey Nicholas C. , Robinson Sian M. , Crozier Sarah R. , Marriott Lynne D. , Gale Catharine R. , Cole Zoe A. , Inskip Hazel M. , Godfrey Keith M. , Cooper Cyrus ,   the Southampton Women's Survey Study Group
Published: April 2009

The impact of variations in current infant feeding practice on bone mineral accrual is not known. We examined the associations between duration of breast-feeding and compliance with infant dietary guidelines and later bone size and density at age 4 years. At total of 599 (318 boys) mother–child pairs were recruited from the Southampton Women's Survey. Duration of breast-feeding was recorded and infant diet was assessed at 6 and 12 months using FFQ. At 6 and 12 months the most important dietary pattern, defined by principal component analysis, was characterised by high consumption of vegetables, fruits and home-prepared foods. As this was consistent with infant feeding recommendations, it was denoted the ‘infant guidelines’ pattern. At age 4 years, children underwent assessment of whole-body bone size and density using a Hologic Discovery dual-energy X-ray absorptiometry instrument. Correlation methods were used to explore the relationships between infant dietary variables and bone mineral. There was no association between duration of breast-feeding in the first year of life and 4-year bone size or density. ‘Infant guidelines’ pattern scores at 6 and 12 months were also unrelated to bone mass at age 4 years. We observed wide variations in current infant feeding practice, but these variations were not associated with differences in childhood bone mass at age 4 years.
Guiding-center recursive Vlasov and Lie-transform methods in plasma physics
Authors: BRIZARD A. J. , MISHCHENKO A.
Published: April 2009

The gyrocenter phase-space transformation used to describe nonlinear gyrokinetic theory is rediscovered by a recursive solution of the Hamiltonian dynamics associated with the perturbed guiding-center Vlasov operator. The present work clarifies the relation between the derivation of the gyrocenter phase-space coordinates by the guiding-center recursive Vlasov method and the method of Lie-transform phase-space transformations.
Fecundity and brood loss in four species of fiddler crabs, genusUca(Brachyura: Ocypodidae), in the mangroves of Inhaca Island, Mozambique
Authors: Torres Paulo , Penha-Lopes Gil , Narciso Luís , Macia Adriano , Paula José
Published: April 2009

In this study, four species of fiddler crabs (Uca) at Inhaca Island, Mozambique, were studied: their fecundity determined and egg loss between the first and last embryonic development stage evaluated. Ovigerous female crabs were collected throughout February to March (wet season) of 2006, during day-time at low tide, in Ponta Rasa (U. annulipesandU. inversa) and Saco (U. chlorophthalmusandU. vocans) mangroves. Average brood size increased significantly with female and species size, ranging from 932 (CW = 8.51 mm) inU. annulipes, to 18,057 (CW = 23.5 mm) inU. vocans. The number of embryos decreased significantly over the incubation period for each species. Brood loss from embryonic stage I to stage IV forU. annulipes, U. inversa, U. chlorophthalmusandU. vocanswas 12.3%, 14%, 43.2% and 23.6%, respectively (P < 0.05). Positive allometry was recorded for all species in the early development stage, however, due to the higher relative brood loss in larger females (U. vocans), when comparing the number of embryos in late developmental stage, a negative allometry was possible to observe. The average volume of embryos at the same stage differed among species although significant differences were found between embryonic stages for all species. Embryo volume increased 96.1%, 93.3%, 92.9% and 96.3% in, respectively,U. annulipes, U. inversa, U. chlorophthalmusandU. vocans(P < 0.05). Differences in brood loss were attributed to habitat substrate and structure, stress factors and behavioural aspects.
Could Time be Change?
Authors: Corish Denis
Published: April 2009

Sydney Shoemaker argues that time without change is possible, but begs the question by assuming an, in effect, Newtonian absolute time, that ‘flows equably’ in a region in which there is no change and in one in which there is. An equally possible, relativist, assumption, consistent, it seems, with relativity theory, is that where nothing changes there is no time flow, though there may be elsewhere, where there is change. Such an assumption would require some revision of uncritical common thought about time. Aristotle argues that there is no time without change but that time is not change. His arguments for the latter can be faulted both internally and again in terms of the same relativist assumption. From thePhysicswe can derive, though Aristotle himself did not, an argument that time is to change as geometrical space is to body: the thing itself in abstraction.
Revisiting the Role of Labor
Authors: Nijhuis Dennie Oude
Published: April 2009

The purpose of this article is to emphasize the importance of the organizational blueprint of labor unions for welfare state outcomes. As a result of the tendency of scholars to view labor as a homogenous and disadvantaged class, the existing literature has paid little attention to this. Many scholars have simply taken labor union support for welfare state development for granted and consequently have focused only on labor union strength. This article argues, rather, that labor union support for welfare state development cannot be taken for granted. It shows that labor unions support or oppose welfare state development depending on their organizational blueprint. This new approach highlights the importance of the labor union movement's organizational structure, as opposed to its organizational strength, for welfare state outcomes. The article also explores how the organizational structure of the labor union movement shapes the stance of employer interest groups toward welfare state development. The empirical findings are based on a comparison of British and Dutch postwar old-age pension development
The Balance of Power in the Balance
Authors: Nexon Daniel H.
Published: April 2009

This article reviews four recent books on balancing and the balance of power. Both in isolation and when taken together, they provide strong analytical and empirical warrants against the proposition that balance of power equilibria represent the “normal condition” or “natural tendency” of international relations. They also reflect the growing dissensus among realists concerning how to conceptualize and operationalize the key concept of “balancing.”

The author argues that their analysis implies a tripartite distinction between balance of power theory, theories of power balances, and theories of balancing. Recognizing this distinction undermines many objections to expanding the concept of balancing to include “nontraditional” variants, but it also helps elucidate why we should eschew describing nontraditional balancing through the language of hard and soft balancing.

Even a more expansive conception of balancing, however, fails to insulate balance of power theory against mounting disconfirming evidence. While one might be able to salvage a “weak” variant of balance of power theory, realists are probably better off adopting a more nuanced and comprehensive approach to power-political competition. The entire field would benefit from treating “balancing” and the “balance of power” as objects of inquiry in their own right, rather than as the province of realist theory.
Seeing Double
Authors: Hafner-Burton Emilie M. , Ron James
Published: April 2009

Over the past two decades, human rights language has spread like wildfire across international policy arenas. The activists who sparked this fire are engaged in two different campaigns. The first is comparatively modest, involving the persuasion of tens of thousands of global elites such as journalists, UN officials, donors, and national political leaders. The second is broader and more complex: to have a real impact on the behavior of tens of millions of state agents worldwide. While most international relations scholars agree that the first campaign has made real gains, opinions are split on the success—past, present, and future—of the second. In part, these divisions fall along methodological lines. With some exceptions, qualitative scholars working in the empirical international relations tradition express more optimism than their quantitative counterparts, whose contributions to the subfield are relatively new. This article reviews several new books on human rights and shows how their insights engage with these ongoing methodological debates. The authors argue that both qualitative and quantitative approaches offer important strengths and that neither has a monopoly on truth. Still, the human rights discourse may be thriving, at least in part, for reasons unrelated to impact. The authors conclude with suggestions for a more systematic and multimethod research, along with a plea for scholarly attention to the potential downsides of international human rights promotion.
Ice Tank Experiments Highlight Changes in Sea Ice Types
Authors: Wilkinson Jeremy P. , DeCarolis Giacomo , Ehlert Iris , Notz Dirk , Evers Karl‐Ulrich , Jochmann Peter , Gerland Sebastian , Nicolaus Marcel , Hughes Nick , Kern Stefan , de la Rosa Sara , Smedsrud Lars , Sakai Shigeki , Shen Hayley , Wadhams Peter
Published: April 2009

With the current and likely continuing reduction of summer sea ice extent in the Arctic Ocean, the predominant mechanism of sea ice formation in the Arctic is likely to change in the future. Although substantial new ice formation occurred under preexisting ice in the past, the fraction of sea ice formation in open water likely will increase significantly. In open water, sea ice formation starts with the development of small ice crystals, called frazil ice, which are suspended in the water column [World Meteorological Organization, 1985]. Under quiescent conditions, these crystals accumulate at the surface to form an unbroken ice sheet known in its early stage as nilas. Under turbulent conditions, caused by wind and waves, frazil ice continues to grow and forms into a thick, soupy mixture called grease ice. Eventually the frazil ice will coalesce into small, rounded pieces known as pancake ice, which finally consolidate into an ice sheet with the return of calm conditions. This frazil/pancake/ice sheet cycle is currently frequently observed in the Antarctic [Lange et al., 1989]. The cycle normally occurs in regions that have a significant stretch of open water, because this allows for the formation of larger waves and hence increased turbulence. Given the increase of such open water in the Arctic Ocean caused by retreating summer sea ice, the frazil/pancake/ice sheet cycle may also become the dominant ice formation process during freezeup in the Arctic.
Ambitious U.S. Federal Budget Proposal Strong on Science, Short on Details
Authors: Showstack Randy
Published: April 2009

The proposed $3.6 trillion U.S. federal budget for fiscal year (FY) 2010, which the Obama administration released on 26 February, includes significant funding for federal science agencies. The budget also emphasizes the development of a comprehensive energy and climate change plan—including a cap and trade program to reduce greenhouse gas emissions—“ to transform our energy supply and slow global warming,” according to the budget document released by the White House Office of Management and Budget (OMB).

However, the 134‐page budget document— which also emphasizes a theme of rebuilding environmental and resource agencies—is thin on specifics. Programmatic budget details will be released in April, according to an OMB senior official.
Scientific integrity memorandum
Authors: Showstack Randy
Published: April 2009

U.S. President Barack Obama signed a presidential memorandum on 9 March to help restore scientific integrity in government decision making. The memorandum directs the White House Office of Science and Technology Policy to develop a strategy within 120 days that ensures that “the selection of scientists and technology professionals for science and technology positions in the executive branch is based on those individuals' scientific and technological knowledge, credentials, and experience; agencies make available to the public the scientific or technological findings or conclusions considered or relied upon in policy decisions; agencies use scientific and technological information that has been subject to well‐established scientific processes such as peer review; and agencies have appropriate rules and procedures to ensure the integrity of the scientific process within the agency, including whistleblower protection.”
Interactions among the environment, society, and the economy
Authors: Showstack Randy
Published: April 2009

The U.S. National Science Foundation's Directorate for Social, Behavioral, and Economic Sciences (SBE) and the Directorate for Geosciences (GEO) have issued a “dear colleague” letter to the scientific community indicating that the directorates “will consider proposals that describe new research efforts relating to the integrated study of environment, society, and economics.”
Mineral and Rock Physics Focus Group Selects Kantor for 2008 Graduate Research Award
Authors: McCammon Catherine
Published: April 2009

The Mineral and Rock Physics focus group has selected Innokenty Kantor as the recipient of the 2008 Graduate Research Award. Kantor pursued his Ph.D. in high‐pressure mineral physics at the Bayerisches Geoinstitut, University of Bayreuth, Germany, under the supervision of Leonid Dubrovinsky and Catherine McCammon, and he successfully defended his thesis, entitled “High‐pressure and high‐temperature structural and electronic properties of (Mg, Fe)O and FeO,” in July 2007. Kantor came to Germany with a strong theoretical background after gaining a master's diploma with honors at Moscow State University, Russia.
Four- and three-phonon scattering in isotropic superfluid helium
Authors: Adamenko I. N. , Kitsenko Yu. A. , Nemchenko K. E. , Wyatt A. F. G.
Published: April 2009

We analyze the important role of four-phonon processes (4pp) in isotropic phonon systems of superfluid helium. The matrix elements and the rate of four-phonon processes are calculated. Special consideration is given to the 4pp in the momentum range where three-phonon processes are allowed. In this momentum range, we show that the 4pp scattering rate, at small angles, is equal to the scattering rate due to three-phonon processes. Then we show that the coefficient of first viscosity of superfluid helium is caused by two processes: the first is due to the transverse relaxation caused by many three-phonon processes, and the second is due to four-phonon processes. The relaxation time that governs the viscosity is obtained from the sum of the rates due to these two processes. The temperature dependence of the attenuation coefficient of a pulse of high-energy phonons in He II, due to scattering with thermal phonons, is also calculated. The theoretical results are compared with experimental data and found to be in good agreement.
Formation of clusters and the percolation threshold in a two-phase system with a random distribution of ZnSe quantum points
Authors: Bondar’ N. V.
Published: April 2009

A characteristic feature due to the formation of a percolation phase transition of carriers has been observed in a two-phase system consisting of borosilicate glass with ZnSe quantum dots. For near-threshold quantum-dot concentrations, changes due to microscopic fluctuations of the quantum-dot density have been observed in the intensities of radiation emission bands. This phenomenon is reminiscent of critical opalescence, where similar fluctuations of the density of a pure substance arise near a phase transition. It is proposed that the dielectric mismatch between the matrix and ZnSe plays a large role in the carrier (exciton) delocalization, resulting in the appearance of a “dielectric trap” on the interface and the formation there of surface states of excitons. The spatial overlapping of states which occurs at the critical concentration of quantum dots results in carrier tunneling and the appearance of a percolation transition in such a system.
Beta-induced Alfvén-acoustic eigenmodes in National Spherical Torus Experiment and DIII-D driven by beam ions
Authors: Gorelenkov N. N. , Van Zeeland M. A. , Berk H. L. , Crocker N. A. , Darrow D. , Fredrickson E. , Fu G.-Y. , Heidbrink W. W. , Menard J. , Nazikian R.
Published: April 2009

Kinetic theory and experimental observations of a special class of energetic particle driven instabilities called here beta-induced Alfvén-acoustic eigenmodes (BAAEs) are reported confirming, previous results [N. N. Gorelenkov et al., Plasma Phys. Controlled Fusion 49, B371 (2007)]. The kinetic theory is based on the ballooning dispersion relation where the drift frequency effects are retained. BAAE gaps are recovered in kinetic theory. It is shown that the observed certain low-frequency instabilities on DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] and National Spherical Torus Experiment [M. Ono, S. M. Kaye, Y.-K. M. Peng et al., Nucl. Fusion 40, 557 (2000)] are consistent with their identification as BAAEs. BAAEs deteriorate the fast ion confinement in DIII-D and can have a similar effect in next-step fusion plasmas, especially if excited together with multiple global toroidicity-induced shear Alfvén eigenmode instabilities. BAAEs can also be used to diagnose safety factor profiles, a technique known as magnetohydrodynamic spectroscopy.
Observation of free exciton photoluminescence emission from single wurtzite GaAs nanowires
Authors: Hoang Thang B. , Moses A. F. , Zhou H. L. , Dheeraj D. L. , Fimland B. O. , Weman H.
Published: April 2009

Microphotoluminescence measurements are used to investigate the optical properties of single wurtzite GaAs nanowires grown by molecular beam epitaxy. The wurtzite GaAs nanowires exhibit a photoluminescence emission peak at 1.544 eV, 29 meV higher than the zinc blende GaAs free exciton energy. Temperature dependent photoluminescence measurements (4.4–70 K) show indications of defect and impurity related emissions at lower energies (1.53–1.54 eV) and the presence of nonradiative defects. High resolution transmission electron microscopy images show a low density of short zinc blende segments sandwiched in between a dominating wurtzite structure and weak photoluminescence emission related to such zinc blende segments is also observed.
Self-excited nonlinear plasma series resonance oscillations in geometrically symmetric capacitively coupled radio frequency discharges
Authors: Donkó Z. , Schulze J. , Czarnetzki U. , Luggenhölscher D.
Published: April 2009

At low pressures, nonlinear self-excited plasma series resonance (PSR) oscillations are known to drastically enhance electron heating in geometrically asymmetric capacitively coupled radio frequency discharges by nonlinear electron resonance heating (NERH). Here we demonstrate via particle-in-cell simulations that high-frequency PSR oscillations can also be excited in geometrically symmetric discharges if the driving voltage waveform makes the discharge electrically asymmetric. This can be achieved by a dual-frequency (f+2f) excitation, when PSR oscillations and NERH are turned on and off depending on the electrical discharge asymmetry, controlled by the phase difference of the driving frequencies.
Calibration of Photometry from the Gemini Multi-Object Spectrograph on Gemini North
Authors: Jørgensen Inger
Published: April 2009

All available observations of photometric standard stars obtained with the Gemini Multi-Object Spectrograph at Gemini North in the period from August 2001 to December 2003 have been used to establish the calibrations for photometry obtained with the instrument. The calibrations presented in this paper are based on significantly more photometric standard star observations than usually used by the individual users. Nightly photometric zero points as well as color terms are determined. The color terms are expected to be valid for all observations taken prior to UT 2004 November 21 at which time the Gemini North primary mirror was coated with silver instead of aluminium. While the nightly zero points are accurate to 0.02 mag or better (random errors), the accuracy of the calibrations is limited by systematic errors from so-called ‘sky concentration’, an effect seen in all focal reducer instruments. We conclude that an accuracy of 0.035 to 0.05 mag can be achieved by using calibrations derived in this paper. The color terms are strongest for very red objects, e.g. for objects with (r′ – z′) = 3.0 the resulting z′ magnitudes will be ≈0.35 mag too bright if the color term is ignored. The calibrations are of importance to the large Gemini user community with data obtained prior to UT 2004 November 21, as well as future users of achive data from this period in time.
Transcriptional regulation differs in affected facioscapulohumeral muscular dystrophy patients compared to asymptomatic related carriers
Authors: Arashiro Patricia , Eisenberg Iris , Kho Alvin T. , Cerqueira Antonia M. P. , Canovas Marta , Silva Helga C. A. , Pavanello Rita C. M. , Verjovski-Almeida Sergio , Kunkel Louis M. , Zatz Mayana
Published: April 2009

Facioscapulohumeral muscular dystrophy (FSHD) is a progressive muscle disorder that has been associated with a contraction of 3.3-kb repeats on chromosome 4q35. FSHD is characterized by a wide clinical inter- and intrafamilial variability, ranging from wheelchair-bound patients to asymptomatic carriers. Our study is unique in comparing the gene expression profiles from related affected, asymptomatic carrier, and control individuals. Our results suggest that the expression of genes on chromosome 4q is altered in affected and asymptomatic individuals. Remarkably, the changes seen in asymptomatic samples are largely in products of genes encoding several chemokines, whereas the changes seen in affected samples are largely in genes governing the synthesis of GPI-linked proteins and histone acetylation. Besides this, the affected patient and related asymptomatic carrier share the 4qA161 haplotype. Thus, these polymorphisms by themselves do not explain the pathogenicity of the contracted allele. Interestingly, our results also suggest that the miRNAs might mediate the regulatory network in FSHD. Together, our results support the previous evidence that FSHD may be caused by transcriptional dysregulation of multiple genes,
in cis
and
in trans
, and suggest some factors potentially important for FSHD pathogenesis. The study of the gene expression profiles from asymptomatic carriers and related affected patients is a unique approach to try to enhance our understanding of the missing link between the contraction in D4Z4 repeats and muscle disease, while minimizing the effects of differences resulting from genetic background.
Reliabilities of identifying positive selection by the branch-site and the site-prediction methods
Authors: Nozawa Masafumi , Suzuki Yoshiyuki , Nei Masatoshi
Published: April 2009

Natural selection operating in protein-coding genes is often studied by examining the ratio (ω) of the rates of nonsynonymous to synonymous nucleotide substitution. The branch-site method (BSM) based on a likelihood ratio test is one of such tests to detect positive selection for a predetermined branch of a phylogenetic tree. However, because the number of nucleotide substitutions involved is often very small, we conducted a computer simulation to examine the reliability of BSM in comparison with the small-sample method (SSM) based on Fisher's exact test. The results indicate that BSM often generates false positives compared with SSM when the number of nucleotide substitutions is ≈80 or smaller. Because the ω value is also used for predicting positively selected sites, we examined the reliabilities of the site-prediction methods, using nucleotide sequence data for the dim-light and color vision genes in vertebrates. The results showed that the site-prediction methods have a low probability of identifying functional changes of amino acids experimentally determined and often falsely identify other sites where amino acid substitutions are unlikely to be important. This low rate of predictability occurs because most of the current statistical methods are designed to identify codon sites with high ω values, which may not have anything to do with functional changes. The codon sites showing functional changes generally do not show a high ω value. To understand adaptive evolution, some form of experimental confirmation is necessary.
A homolog of human ski-interacting protein in rice positively regulates cell viability and stress tolerance
Authors: Hou Xin , Xie Kabin , Yao Jialing , Qi Zhuyun , Xiong Lizhong
Published: April 2009

Abiotic stresses are major limiting factors for growth, development, and productivity of crop plants. Here, we report on OsSKIPa, a rice homolog of human Ski-interacting protein (SKIP) that can complement the lethal defect of the knockout mutant of SKIP homolog in yeast and positively modulate cell viability and stress tolerance of rice. Suppression of
OsSKIPa
in rice resulted in growth arrest and reduced cell viability. The expression
OsSKIPa
is induced by various abiotic stresses and phytohormone treatments. Transgenic rice overexpressing
OsSKIPa
exhibited significantly improved growth performance in the medium containing stress agents (abscisic acid, salt, or mannitol) and drought resistance at both the seedling and reproductive stages. The
OsSKIPa
-overexpressing rice showed significantly increased reactive oxygen species-scavenging ability and transcript levels of many stress-related genes, including
SNAC1
and rice homologs of
CBF2
,
PP2C
, and
RD22
, under drought stress conditions. More than 30 OsSKIPa-interacting proteins were identified, but most of these proteins have no matches with the reported SKIP-interacting proteins in animals and yeast. Together, these data suggest that OsSKIPa has evolved a specific function in positive modulation of stress resistance through transcriptional regulation of diverse stress-related genes in rice.
A statistical-spectral method for echo classification
Authors: Demer David A. , Cutter George R. , Renfree Josiah S. , Butler John L.
Published: April 2009

Demer, D. A., Cutter, G. R., Renfree, J. S., and Butler, J. L. 2009. A statistical-spectral method for echo classification. – ICES Journal of Marine Science, 66: 1081–1090. The frequency dependence of sound-scatter intensity is commonly exploited to classify fish, zooplankton, and the seabed observed in acoustic surveys. Although less utilized, techniques based on the statistics of echo amplitudes can also be used to extract information. For example, single-frequency echo statistics have been used to determine whether backscatter originates from single or multiple fish or from rough or smooth seabeds, and to estimate scatterer sizes and densities. The efficacies of the amplitude-based techniques are challenged, however, by the usual requirement to group echo measurements to facilitate meaningful comparisons with model predictions. Groupings of data over space, time, or both, can combine scatter from multiple taxa or species, confounding the comparisons. These methods are improved with a hybrid, statistical-spectral method for target identification (SSID), which incorporates information contained in both the signal amplitudes and phases. The SSID uses multifrequency echo statistics from individual time-space intensities (pixels) to identify general scattering types, before applying model-based identification schemes for target identifications. The effectiveness of the SSID is demonstrated for fine-scale separation of scatter from demersal fish and the seabed and estimating seabed depth, within-beam slope, hardness and roughness, and the height of the dynamic acoustic dead zone.
Effects of floral thermogenesis on pollen function in Asian skunk cabbage
Symplocarpus renifolius
Authors: Seymour Roger S. , Ito Yuka , Onda Yoshihiko , Ito Kikukatsu
Published: April 2009

The effects of temperature on pollen germination and pollen tube growth rate were measured
in vitro
in thermogenic skunk cabbage,
Symplocarpus renifolius
Schott ex Tzvelev, and related to floral temperatures in the field. This species has physiologically thermoregulatory spadices that maintain temperatures near 23°C, even in sub-freezing air. Tests at 8, 13, 18, 23, 28 and 33°C showed sharp optima at 23°C for both variables, and practically no development at 8°C. Thermogenesis is therefore a requirement for fertilization in early spring. The narrow temperature tolerance is probably related to a long period of evolution in flowers that thermoregulate within a narrow range.
Humans at tropical latitudes produce more females
Authors: Navara Kristen J.
Published: April 2009

Skews in the human sex ratio at birth have captivated scientists for over a century. The accepted average human natal sex ratio is slightly male biased, at 106 males per 100 females or 51.5 per cent males. Studies conducted on a localized scale show that sex ratios deviate from this average in response to a staggering number of social, economical and physiological variables. However, these patterns often prove inconsistent when expanded to other human populations, perhaps because the nature of the influences themselves exhibit substantial cultural variation. Here, data collected from 202 countries over a decade show that latitude is a primary factor influencing the ratio of males and females produced at birth; countries at tropical latitudes produced significantly fewer boys (51.1% males) annually than those at temperate and subarctic latitudes (51.3%). This pattern remained strong despite enormous continental variation in lifestyle and socio-economic status, suggesting that latitudinal variables may act as overarching cues on which sex ratio variation in humans is based.
Swimming patterns and dynamics of simulated
Escherichia coli
bacteria
Authors: Zonia Laura , Bray Dennis
Published: April 2009

A spatially and temporally realistic simulation of
Escherichia coli
chemotaxis was used to investigate the swimming patterns of wild-type and mutant bacteria within a rectangular arena in response to chemoattractant gradients. Swimming dynamics were analysed during long time series with phase-space trajectories, power spectra and estimations of fractal dimensions (FDs). Cell movement displayed complex trajectories in the phase space owing to interaction of multiple attractors that captured runs and tumbles. Deletion of enzymes responsible for adaptation (CheR and CheB) restricted the pattern of bacterial swimming in the absence of a gradient. In the presence of a gradient, there was a strong increase in trajectories arising from runs and attenuation of those arising from tumbles. Similar dynamics were observed for mutants lacking CheY, which are unable to tumble. The deletion of CheR, CheB and CheY also caused significant shifts in chemotaxis spectral frequencies. Rescaled range analysis and estimation of FD suggest that wild-type bacteria display characteristics of fractional Brownian motion with positive correlation between past and future events. These results reveal an underlying order in bacterial swimming dynamics, which enables a chemotactic search strategy conforming to a fractal walk.
Optimal control of epidemics in metapopulations
Authors: Rowthorn Robert E. , Laxminarayan Ramanan , Gilligan Christopher A.
Published: April 2009

Little is known about how best to deploy scarce resources for disease control when epidemics occur in different but interconnected regions. We use a combination of optimal control methods and epidemiological theory for metapopulations to address this problem. We consider what strategy should be used if the objective is to minimize the discounted number of infected individuals during the course of an epidemic. We show, for a system with two interconnected regions and an epidemic in which infected individuals recover and can be reinfected, that equalizing infection in the two regions is the worst possible strategy in minimizing the total level of infection. Treatment should instead be preferentially directed at the region with the lower level of infection, treating the other subpopulation only when there is resource left over. The same strategy holds with preferential treatments of regions with lower levels of infection when quarantine is introduced.
On optimal decision-making in brains and social insect colonies
Authors: Marshall James A. R. , Bogacz Rafal , Dornhaus Anna , Planqué Robert , Kovacs Tim , Franks Nigel R.
Published: April 2009

The problem of how to compromise between speed and accuracy in decision-making faces organisms at many levels of biological complexity. Striking parallels are evident between decision-making in primate brains and collective decision-making in social insect colonies: in both systems, separate populations accumulate evidence for alternative choices; when one population reaches a threshold, a decision is made for the corresponding alternative, and this threshold may be varied to compromise between the speed and the accuracy of decision-making. In primate decision-making, simple models of these processes have been shown, under certain parametrizations, to implement the statistically optimal procedure that minimizes decision time for any given error rate. In this paper, we adapt these same analysis techniques and apply them to new models of collective decision-making in social insect colonies. We show that social insect colonies may also be able to achieve statistically optimal collective decision-making in a very similar way to primate brains, via direct competition between evidence-accumulating populations. This optimality result makes testable predictions for how collective decision-making in social insects should be organized. Our approach also represents the first attempt to identify a common theoretical framework for the study of decision-making in diverse biological systems.
Correction for Bakhtar
et al.
, Instability in two-phase flows of steam
Authors: Bakhtar F. , Otto S. R. , Zamri M. Y. , Sarkies M.
Published: April 2009

Correction for ‘Instability in two-phase flows of steam’ by F. Bakhtar, S. R. Otto, M. Y. Zamri and M. Sarkies (Proc. R. Soc. A
464
, 537–553.
(doi:
10.1098/rspa.2007.0087
)).

The following equation contains typographical errors that has no consequence for any other equation or result in the above paper.
Stress and translocation: alterations in the stress physiology of translocated birds
Authors: Dickens Molly J. , Delehanty David J. , Romero L. Michael
Published: April 2009

Translocation and reintroduction have become major conservation actions in attempts to create self-sustaining wild populations of threatened species. However, avian translocations have a high failure rate and causes for failure are poorly understood. While ‘stress’ is often cited as an important factor in translocation failure, empirical evidence of physiological stress is lacking. Here we show that experimental translocation leads to changes in the physiological stress response in chukar partridge,
Alectoris chukar
. We found that capture alone significantly decreased the acute glucocorticoid (corticosterone, CORT) response, but adding exposure to captivity and transport further altered the stress response axis (the hypothalamic–pituitary–adrenal axis) as evident from a decreased sensitivity of the negative feedback system. Animals that were exposed to the entire translocation procedure, in addition to the reduced acute stress response and disrupted negative feedback, had significantly lower baseline CORT concentrations and significantly reduced body weight. These data indicate that translocation alters stress physiology and that chronic stress is potentially a major factor in translocation failure. Under current practices, the restoration of threatened species through translocation may unwittingly depend on the success of chronically stressed individuals. This conclusion emphasizes the need for understanding and alleviating translocation-induced chronic stress in order to use most effectively this important conservation tool.
Testosterone-mediated trade-offs in the old age: a new approach to the immunocompetence handicap and carotenoid-based sexual signalling
Authors: Alonso-Alvarez C. , Pérez-Rodríguez Lorenzo , Garcia Jesus T. , Viñuela Javier
Published: April 2009

The immunocompetence handicap hypothesis proposes that testosterone mediates a trade-off between sexual signalling and immunocompetence in males. Such a trade-off could favour the reliability of sexual signals on the basis that testosterone required for signal expression also promotes immunosuppression. However, the immunosuppressive activity of testosterone has not been convincingly demonstrated. We propose that the optimal solution to the testosterone-mediated trade-off should change with age, explaining ambiguous results in the past. Testosterone and ageing would promote two simultaneous immunosuppressive challenges unaffordable for low-quality males. Oxidative stress, as intimately related to ageing and immunosenescence, could contribute to enhance signal reliability. In this context, traits coloured by carotenoids (yellow–red traits) could play a crucial role due to the immunostimulatory and antioxidant properties of these pigments. Here, old and middle-aged male red-legged partridges were treated with testosterone or manipulated as controls. In the presence of high-testosterone levels, middle-aged males increased both circulating carotenoid levels and colour expression, whereas their cell-mediated immunity was not significantly altered. However, in old males, neither circulating carotenoids nor sexual signalling increased when treated with testosterone, but immunosuppression was detected. The link between testosterone and carotenoids could favour the reliability of sexual signals throughout the life.
An experimental test of the independent action hypothesis in virus–insect pathosystems
Authors: Zwart Mark P. , Hemerik Lia , Cory Jenny S. , de Visser J. Arjan G.M. , Bianchi Felix J.J.A. , Van Oers Monique M. , Vlak Just M. , Hoekstra Rolf F. , Van der Werf Wopke
Published: April 2009

The ‘independent action hypothesis’ (IAH) states that each pathogen individual has a non-zero probability of causing host death and that pathogen individuals act independently. IAH has not been rigorously tested. In this paper, we (i) develop a probabilistic framework for testing IAH and (ii) demonstrate that, in two out of the six virus–insect pathosystems tested, IAH is supported by the data. We first show that IAH inextricably links host survivorship to the number of infecting pathogen individuals, and develop a model to predict the frequency of single- and dual-genotype infections when a host is challenged with a mixture of two genotypes. Model predictions were tested using genetically marked, near-identical baculovirus genotypes, and insect larvae from three host species differing in susceptibility. Observations in early-instar larvae of two susceptible host species support IAH, but observations in late-instar larvae of susceptible host species and larvae of a less susceptible host species were not in agreement with IAH. Hence the model is experimentally supported only in pathosystems in which the host is highly susceptible. We provide, to our knowledge, the first qualitative experimental evidence that, in such pathosystems, the action of a single virion is sufficient to cause disease.
Emperor penguin mates: keeping together in the crowd
Authors: Ancel André , Beaulieu Michaël , Le Maho Yvon , Gilbert Caroline
Published: April 2009

As emperor penguins have no breeding territories, a key issue for both members of a pair is not to be separated until the egg is laid and transferred to the male. Both birds remain silent after mating and thereby reduce the risk of having the pair bond broken by unpaired birds. However, silence prevents finding each other if the pair is separated. Huddles—the key to saving energy in the cold and the long breeding fast—continuously form and break up, but not all birds are involved simultaneously. We studied the behaviour of four pairs before laying. Temperature and light intensity measurements allowed us to precisely detect the occurrence of huddling episodes and to determine the surrounding temperature. The four pairs huddled simultaneously for only 6 per cent of the time when weather conditions were harshest. Despite this asynchrony, the huddling behaviour and the resulting benefits were similar between pairs. By contrast, the huddling behaviour of mates was synchronized for 84 per cent of events. By coordinating their huddling behaviour during courtship despite the apparent confusion within a huddle and its ever-changing structure, both individuals save energy while securing their partnership.
Development of a questionnaire to measure patient‐reported postoperative recovery: content validity and intra‐patient reliability
Authors: Allvin Renée , Ehnfors Margareta , Rawal Narinder , Svensson Elisabeth , Idvall Ewa
Published: April 2009

Aims and objectives In this study we describe the development of a short, easy‐to‐use questionnaire to measure postoperative recovery and evaluate its content validity and intra‐patient reliability. The questionnaire is designed to evaluate the progress of postoperative recovery and the long‐term follow‐up of possible effects of interventions during recovery.

Methods The study involved four steps. (1) A conceptualization and item definitions were based on a theoretical framework and a description of patients’ postoperative recovery from the perspective of patients, registered nurses and surgeons; (2) Content validity of items was tested through expert judgements; (3) A test run of the questionnaire was performed to confirm its feasibility and workload requirement; and (4) The stability of the questionnaire was evaluated through intra‐patient reliability assessment.

Results As a result of the operationalization process of the concept postoperative recovery, five dimensions (physical symptoms, physical functions, psychological, social, activity) and 19 items were identified. Each item was formulated as a statement in the questionnaire. Content validity was judged to be high. After the pre‐test of the questionnaire a revision with refinements in the layout was made. The vast majority of items showed a high level of intra‐patient reliability.

Conclusion Based on a theoretical framework and empirical data, we developed a short and easy‐to‐use tentative questionnaire to measure patient‐reported postoperative recovery. Initial support for content validity was established. The vast majority of items showed a high level of test–retest reliability.
Hygroreception in olfactometer studies
Authors: MARTÍNEZ ANDRÉS S. , HARDIE JIM
Published: April 2009

Abstract In olfactometric studies, a technique used to measure insect behavioural bias towards airborne chemicals, many of the factors that could affect the bioassay outcome other than the volatiles themselves are carefully controlled (e.g. lighting conditions, temperature, spatial position, physiological state of the insects, time of day when the bioassay is performed) but one factor, namely humidity, is overlooked frequently when studying responses to plant volatiles. Many insect species respond positively and negatively to changes in humidity and, during bioassays, differences arising from odour choices with different water vapour release rates might have confounding effects versus the original intent of the behavioural study. The present study aims to assess the effect of different substrates on the water vapour content of air in an olfactometer‐like set‐up. The results show that airflow humidity is affected by the odour source used in the olfactometer air flow. In addition, the response of the aphid parasitoid Aphidius colemani Viereck (Hymenoptera: Aphidiidae) is studied towards different humidities and plant material in an olfactometer. The present study suggests that humidity needs to be controlled in olfactometric studies.