bluuebunny/crossref_metadata_2025 huggingface dataset:
Finite element modelling versus classic beam theory: comparing methods for stress estimation in a morphologically diverse sample of vertebrate long bones
Authors: Brassey Charlotte A. , Margetts Lee , Kitchener Andrew C. , Withers Philip J. , Manning Phillip L. , Sellers William I.
Published: November 2012

Classic beam theory is frequently used in biomechanics to model the stress behaviour of vertebrate long bones, particularly when creating intraspecific scaling models. Although methodologically straightforward, classic beam theory requires complex irregular bones to be approximated as slender beams, and the errors associated with simplifying complex organic structures to such an extent are unknown. Alternative approaches, such as finite element analysis (FEA), while much more time-consuming to perform, require no such assumptions. This study compares the results obtained using classic beam theory with those from FEA to quantify the beam theory errors and to provide recommendations about when a full FEA is essential for reasonable biomechanical predictions. High-resolution computed tomographic scans of eight vertebrate long bones were used to calculate diaphyseal stress owing to various loading regimes. Under compression, FEA values of minimum principal stress (σmin) were on average 142 per cent (±28% s.e.) larger than those predicted by beam theory, with deviation between the two models correlated to shaft curvature (two-tailedp= 0.03,r2= 0.56). Under bending, FEA values of maximum principal stress (σmax) and beam theory values differed on average by 12 per cent (±4% s.e.), with deviation between the models significantly correlated to cross-sectional asymmetry at midshaft (two-tailedp= 0.02,r2= 0.62). In torsion, assuming maximum stress values occurred at the location of minimum cortical thickness brought beam theory and FEA values closest in line, and in this case FEA values ofτtorsionwere on average 14 per cent (±5% s.e.) higher than beam theory. Therefore, FEA is the preferred modelling solution when estimates of absolute diaphyseal stress are required, although values calculated by beam theory for bending may be acceptable in some situations.
Electrical innovations, authority and consulting expertise in late Victorian Britain
Authors: Arapostathis Stathis
Published: November 2012

In this article I examine the practices of electrical engineering experts, with special reference to their role in the implementation of innovations in late Victorian electrical networks. I focus on the consulting work of two leading figures in the scientific and engineering world of the period, Alexander Kennedy and William Preece. Both were Fellows of the Royal Society and both developed large-scale consulting activities in the emerging electrical industry of light and power. At the core of the study I place the issues of trust and authority, and the bearing of these on the engineering expertise of consultants in late Victorian Britain. I argue that the ascription of expertise to these engineers and the trust placed in their advice were products of power relations on the local scale. The study seeks to unravel both the technical and the social reasons for authoritative patterns of consulting expertise.
The effect of sexual harassment on lethal mutation rate in femaleDrosophila melanogaster
Authors: Maklakov Alexei A. , Immler Simone , Løvlie Hanne , Flis Ilona , Friberg Urban
Published: November 2012

The rate by which new mutations are introduced into a population may have far-reaching implications for processes at the population level. Theory assumes that all individuals within a population have the same mutation rate, but this assumption may not be true. Compared with individuals in high condition, those in poor condition may have fewer resources available to invest in DNA repair, resulting in elevated mutation rates. Alternatively, environmentally induced stress can result in increased investment in DNA repair at the expense of reproduction. Here, we directly test whether sexual harassment by males, known to reduce female condition, affects female capacity to alleviate DNA damage inDrosophila melanogasterfruitflies. Female gametes can repair double-strand DNA breaks in sperm, which allows manipulating mutation rate independently from female condition. We show that male harassment strongly not only reduces female fecundity, but also reduces the yield of dominant lethal mutations, supporting the hypothesis that stressed organisms invest relatively more in repair mechanisms. We discuss our results in the light of previous research and suggest that social effects such as density and courtship can play an important and underappreciated role in mediating condition-dependent mutation rate.
Aphids evolved novel secreted proteins for symbiosis with bacterial endosymbiont
Authors: Shigenobu Shuji , Stern David L.
Published: November 2012

Aphids evolved novel cells, called bacteriocytes, that differentiate specifically to harbour the obligatory mutualistic endosymbiotic bacteria
Buchnera aphidicola
. The genome of the host aphid
Acyrthosiphon pisum
contains many orphan genes that display no similarity with genes found in other sequenced organisms, prompting us to hypothesize that some of these orphan genes are related to lineage-specific traits, such as symbiosis. We conducted deep sequencing of bacteriocytes mRNA followed by whole mount
in situ
hybridizations of over-represented transcripts encoding aphid-specific orphan proteins. We identified a novel class of genes that encode small proteins with signal peptides, which are often cysteine-rich, that are over-represented in bacteriocytes. These genes are first expressed at a developmental time point coincident with the incorporation of symbionts strictly in the cells that contribute to the bacteriocyte and this bacteriocyte-specific expression is maintained throughout the aphid's life. The expression pattern suggests that recently evolved secretion proteins act within bacteriocytes, perhaps to mediate the symbiosis with beneficial bacterial partners, which is reminiscent of the evolution of novel cysteine-rich secreted proteins of leguminous plants that regulate nitrogen-fixing endosymbionts.
Source population characteristics affect heterosis following genetic rescue of fragmented plant populations
Authors: Pickup M. , Field D. L. , Rowell D. M. , Young A. G.
Published: November 2012

Understanding the relative importance of heterosis and outbreeding depression over multiple generations is a key question in evolutionary biology and is essential for identifying appropriate genetic sources for population and ecosystem restoration. Here we use 2455 experimental crosses between 12 population pairs of the rare perennial plant
Rutidosis leptorrhynchoides
(Asteraceae) to investigate the multi-generational (F
1
, F
2
, F
3
) fitness outcomes of inter-population hybridization. We detected no evidence of outbreeding depression, with inter-population hybrids and backcrosses showing either similar fitness or significant heterosis for fitness components across the three generations. Variation in heterosis among population pairs was best explained by characteristics of the foreign source or home population, and was greatest when the source population was large, with high genetic diversity and low inbreeding, and the home population was small and inbred. Our results indicate that the primary consideration for maximizing progeny fitness following population augmentation or restoration is the use of seed from large, genetically diverse populations.
Ecological traits affect the response of tropical forest bird species to land-use intensity
Authors: Newbold Tim , Scharlemann Jörn P. W. , Butchart Stuart H. M. , Şekercioğlu Çağan H. , Alkemade Rob , Booth Hollie , Purves Drew W.
Published: November 2012

Land-use change is one of the main drivers of current and likely future biodiversity loss. Therefore, understanding how species are affected by it is crucial to guide conservation decisions. Species respond differently to land-use change, possibly related to their traits. Using pan-tropical data on bird occurrence and abundance across a human land-use intensity gradient, we tested the effects of seven traits on observed responses. A likelihood-based approach allowed us to quantify uncertainty in modelled responses, essential for applying the model to project future change. Compared with undisturbed habitats, the average probability of occurrence of bird species was 7.8 per cent and 31.4 per cent lower, and abundance declined by 3.7 per cent and 19.2 per cent in habitats with low and high human land-use intensity, respectively. Five of the seven traits tested affected the observed responses significantly: long-lived, large, non-migratory, primarily frugivorous or insectivorous forest specialists were both less likely to occur and less abundant in more intensively used habitats than short-lived, small, migratory, non-frugivorous/insectivorous habitat generalists. The finding that species responses to land use depend on their traits is important for understanding ecosystem functioning, because species' traits determine their contribution to ecosystem processes. Furthermore, the loss of species with particular traits might have implications for the delivery of ecosystem services.
Ecological selection as the cause and sexual differentiation as the consequence of species divergence?
Authors: Oneal Elen , Knowles L. Lacey
Published: November 2012

Key conceptual issues about speciation go unanswered without consideration of non-mutually exclusive factors. With tests based on speciation theory, we exploit the island distribution and habitat differences exhibited by the Caribbean cricketAmphiacusta sanctaecrucis, and with an analysis of divergent ecological selection, sexually selected differentiation and geographical isolation, address how these different factors interact. After testing for divergent selection by comparing neutral genetic and morphological divergence in one ecological (mandible shape) and one sexual (male genitalia shape) trait, we examine whether ecological or sexual selection is the primary mechanism driving population divergence. We find that all three factors—isolation, ecological and sexual selection—contribute to divergence, and that their interaction determines the stage of completeness achieved during the speciation process, as measured by patterns of genetic differentiation. Moreover, despite the striking diversity in genitalic shapes across the genusAmphiacusta, which suggests that sexual selection drives speciation, the significant differences in genitalia shape between forest habitats revealed here implies that ecological divergence may be the primary axis of divergence. Our work highlights critical unstudied aspects in speciation—differentiating the cause from the consequence of divergence—and suggests avenues for further disentangling the roles of natural and sexual selection in driving divergence inAmphiacusta.
Linking brains and brawn: exercise and the evolution of human neurobiology
Authors: Raichlen David A. , Polk John D.
Published: November 2012

The hunting and gathering lifestyle adopted by human ancestors around 2 Ma required a large increase in aerobic activity. High levels of physical activity altered the shape of the human body, enabling access to new food resources (e.g. animal protein) in a changing environment. Recent experimental work provides strong evidence that both acute bouts of exercise and long-term exercise training increase the size of brain components and improve cognitive performance in humans and other taxa. However, to date, researchers have not explored the possibility that the increases in aerobic capacity and physical activity that occurred during human evolution directly influenced the human brain. Here, we hypothesize that proximate mechanisms linking physical activity and neurobiology in living species may help to explain changes in brain size and cognitive function during human evolution. We review evidence that selection acting on endurance increased baseline neurotrophin and growth factor signalling (compounds responsible for both brain growth and for metabolic regulation during exercise) in some mammals, which in turn led to increased overall brain growth and development. This hypothesis suggests that a significant portion of human neurobiology evolved due to selection acting on features unrelated to cognitive performance.
Rain reverses diel activity rhythms in an estuarine teleost
Authors: Payne Nicholas L. , van der Meulen Dylan E. , Gannon Ruan , Semmens Jayson M. , Suthers Iain M. , Gray Charles A. , Taylor Matthew D.
Published: November 2012

Activity rhythms are ubiquitous in nature, and generally synchronized with the day–night cycle. Several taxa have been shown to switch between nocturnal and diurnal activity in response to environmental variability, and these relatively uncommon switches provide a basis for greater understanding of the mechanisms and adaptive significance of circadian (approx. 24 h) rhythms. Plasticity of activity rhythms has been identified in association with a variety of factors, from changes in predation pressure to an altered nutritional or social status. Here, we report a switch in activity rhythm that is associated with rainfall. Outside periods of rain, the estuarine-associated teleost
Acanthopagrus australis
was most active and in shallower depths during the day, but this activity and depth pattern was reversed in the days following rain, with diurnality restored as estuarine conductivity and turbidity levels returned to pre-rain levels. Although representing the first example of a rain-induced reversal of activity rhythm in an aquatic animal of which we are aware, our results are consistent with established models on the trade-offs between predation risk and foraging efficiency.
Local and electronic structure around Ga in CdTe: evidence of DX- and A-centers
Authors: Koteski Vasil , Belošević-Čavor Jelena , Fochuk Petro , Mahnke Heinz-Eberhard
Published: November 2012

The lattice relaxation around Ga in CdTe is investigated by means of extended X-ray absorption spectroscopy (EXAFS) and density functional theory (DFT) calculations using the linear augmented plane waves plus local orbitals (LAPW+lo) method. In addition to the substitutional position, the calculations are performed for DX- and A-centers of Ga in CdTe. The results of the calculations are in good agreement with the experimental data, as obtained from EXAFS and X-ray absorption near-edge structure (XANES). They allow the experimental identification of several defect structures in CdTe. In particular, direct experimental evidence for the existence of DX-centers in CdTe is provided, and for the first time the local bond lengths of this defect are measured directly.
Thermal Conductivity Test of YBCO Coated Conductor Tape Stacks Interleaved With Insulated Stainless Steel Tapes
Authors: Bai Hongyu , Markiewicz W , Lu Jun , Weijers Hubertus
Published: November 2012

A 32 Tesla, all-superconducting user magnet, which consists of two high temperature superconductor YBCO inner coils producing a field of 17 T in an low temperature superconductor Nb3Sn and NbTi outer magnet producing a background field of 15 T, is being developed at the National High Magnetic Field Laboratory. The YBCO inner coils are pancake-wound with YBCO coated conductor tapes with an interleaved insulation of sol-gel coated stainless steel tapes. The coils are to be cooled directly in liquid helium bath. Heat losses in the windings, such as ac losses during ramping and heat loss in the internal joints, are supposed to be transferred to the coil external surfaces through heat conduction. Thus, thermal conductivity of the coil structure is critical for the internal cooling of the coil and also quench propagation if any. Thermal conductivity measurements were carried out in the radial direction on stacks of alternating YBCO tapes and stainless steel tapes. This paper presents the test results that showed a very low thermal conductivity in the radial direction. For comparison purposes, calculated thermal conductivities in the axial and azimuthal direction are also presented.
Tour Planning for Mobile Data-Gathering Mechanisms in Wireless Sensor Networks
Authors: Ma Ming , Yang Yuanyuan , Zhao Miao
Published: November 2012

In this paper, we propose a new data-gathering mechanism for large-scale wireless sensor networks by introducing mobility into the network. A mobile data collector, for convenience called an M-collector in this paper, could be a mobile robot or a vehicle equipped with a powerful transceiver and battery, working like a mobile base station and gathering data while moving through the field. An M-collector starts the data-gathering tour periodically from the static data sink, polls each sensor while traversing its transmission range, then directly collects data from the sensor in single-hop communications, and finally transports the data to the static sink. Since data packets are directly gathered without relays and collisions, the lifetime of sensors is expected to be prolonged. In this paper, we mainly focus on the problem of minimizing the length of each data-gathering tour and refer to this as the single-hop data-gathering problem (SHDGP). We first formalize the SHDGP into a mixed-integer program and then present a heuristic tour-planning algorithm for the case where a single M-collector is employed. For the applications with strict distance/time constraints, we consider utilizing multiple M-collectors and propose a data-gathering algorithm where multiple M-collectors traverse through several shorter subtours concurrently to satisfy the distance/time constraints. Our single-hop mobile data-gathering scheme can improve the scalability and balance the energy consumption among sensors. It can be used in both connected and disconnected networks. Simulation results demonstrate that the proposed data-gathering algorithm can greatly shorten the moving distance of the collectors compared with the covering line approximation algorithm and is close to the optimal algorithm for small networks. In addition, the proposed data-gathering scheme can significantly prolong the network lifetime compared with a network with static data sink or a network in which the mobile collector c- n only move along straight lines.
Quantifying individual variation in behaviour: mixed‐effect modelling approaches
Authors: Dingemanse Niels J. , Dochtermann Ned A.
Published: November 2012

Growing interest in proximate and ultimate causes and consequences of between‐ and within‐individual variation in labile components of the phenotype – such as behaviour or physiology – characterizes current research in evolutionary ecology.

The study of individual variation requires tools for quantification and decomposition of phenotypic variation into between‐ and within‐individual components. This is essential as variance components differ in their ecological and evolutionary implications.

We provide an overview of how mixed‐effect models can be used to partition variation in, and correlations among, phenotypic attributes into between‐ and within‐individual variance components.

Optimal sampling schemes to accurately estimate (with sufficient power) a wide range of repeatabilities and key (co)variance components, such as between‐ and within‐individual correlations, are detailed.

Mixed‐effect models enable the usage of unambiguous terminology for patterns of biological variation that currently lack a formal statistical definition (e.g. ‘animal personality’ or ‘behavioural syndromes’), and facilitate cross‐fertilisation between disciplines such as behavioural ecology, ecological physiology and quantitative genetics.
Vegetation dynamics drive segregation by body size in Galapagos tortoises migrating across altitudinal gradients
Authors: Blake Stephen , Yackulic Charles B. , Cabrera Fredy , Tapia Washington , Gibbs James P. , Kümmeth Franz , Wikelski Martin
Published: November 2012

Seasonal migration has evolved in many taxa as a response to predictable spatial and temporal variation in the environment. Individual traits, physiology and social state interact with environmental factors to increase the complexity of migratory systems. Despite a huge body of research, the ultimate causes of migration remain unclear.

A relatively simple, tractable system – giant tortoises on Santa Cruz Island, Galapagos, was studied to elucidate the roles of environmental variation and individual traits in a partial migratory system. Specifically, we asked: (i) do Galapagos tortoises undergo long‐distance seasonal migrations? (ii) is tortoise migration ultimately driven by gradients in forage quality or temperature; and (iii) how do sex and body size influence migration patterns?

We recorded the daily locations of 17 GPS‐tagged tortoises and walked a monthly survey along the altitudinal gradient to characterize the movements and distribution of tortoises of different sizes and sexes. Monthly temperature and rainfall data were obtained from weather stations deployed at various altitudes, and the Normalized Difference Vegetation Index was used as a proxy for forage quality.

Analyses using net displacement or daily movement characteristics did not agree on assigning individuals as either migratory or non‐migratory; however, both methods suggested that some individuals were migratory. Adult tortoises of both sexes move up and down an altitudinal gradient in response to changes in vegetation dynamics, not temperature. The largest tagged individuals all moved, whereas only some mid‐sized individuals moved, and the smallest individuals never left lowland areas. The timing of movements varied with body size: large individuals moved upward (as lowland forage quality declined) earlier in the year than did mid‐sized individuals, while the timing of downward movements was unrelated to body size and occurred as lowland vegetation productivity peaked.

Giant tortoises are unlikely candidates for forage‐driven migration as they are well buffered against environmental fluctuations by large body size and a slow metabolism. Notably the largest, and presumably most dominant, individuals were most likely to migrate. This characteristic and the lack of sex‐based differences in movement behaviour distinguish Galapagos tortoise movement from previously described partial migratory systems.
Probucol prevents blood–brain barrier dysfunction in wild‐type mice induced by saturated fat or cholesterol feeding
Authors: Takechi Ryusuke , Galloway Susan , Pallebage‐Gamarallage Menuka M , Lam Virginie , Dhaliwal Satvinder S , Mamo John C
Published: November 2012

Dysfunction of the blood–brain barrier (BBB) is an early pathological feature of vascular dementia and Alzheimer's disease (AD) and is triggered by inflammatory stimuli. Probucol is a lipid‐lowering agent with potent anti‐oxidant properties once commonly used for the treatment of cardiovascular disease. Probucol therapy was found to stabilize cognitive symptoms in elderly AD patients, whereas in amyloid transgenic mice probucol was shown to attenuate amyloidosis. However, the mechanisms underlying the effects of probucol have note been determined.

In the present study we investigated whether probucol can prevent BBB disturbances induced by chronic ingestion of proinflammatory diets enriched with either 20% (w/w) saturated fats (SFA) or 1% (w/w) cholesterol. Mice were fed the diets for 12 weeks before they were killed and BBB integrity was measured.

Mice maintained on either the SFA‐ or cholesterol‐supplemented diets were found to have a 30‐ and sevenfold greater likelihood of BBB dysfunction, respectively, as determined by the parenchymal extravasation of plasma‐derived immunoglobulins and endogenous lipoprotein enrichment with β‐amyloid. In contrast, mice fed the SFA‐ or cholesterol‐enriched diets that also contained 1% (w/w) probucol showed no evidence of BBB disturbance. The parenchymal expression of glial fibrillary acidic protein, a marker of cerebrovascular inflammation, was significantly greater in mice fed the SFA‐enriched diet. Plasma lipid, β‐amyloid and apolipoprotein B levels were not increased by feeding of the SFA‐ or cholesterol‐enriched diets. However, mice fed the SFA‐ or cholesterol‐enriched diets did exhibit increased plasma non‐esterified fatty acid levels that were not reduced by probucol.

The data suggest that probucol prevents disturbances of BBB induced by chronic ingestion of diets enriched in SFA or cholesterol by suppressing inflammatory pathways rather than by modulating plasma lipid homeostasis.
Reward for Bdellovibrio bacteriovorus for preying on a polyhydroxyalkanoate producer
Authors: Martínez Virginia , Jurkevitch Edouard , García José Luis , Prieto María Auxiliadora
Published: November 2012

Bdellovibrio bacteriovorus HD100 is an obligate predator that invades and grows within the periplasm of Gram‐negative bacteria, including mcl‐polyhydroxyalkanoate (PHA) producers such as Pseudomonas putida. We investigated the impact of prey PHA content on the predator fitness and the potential advantages for preying on a PHA producer. Using a new procedure to control P. putida KT2442 cell size we demonstrated that the number of Bdellovibrio progeny depends on the prey biomass and not on the viable prey cell number or PHA content. The presence of mcl‐PHA hydrolysed products in the culture supernatant after predation on P. putida KT42Z, a PHA producing strain lacking PhaZ depolymerase, confirmed the ability of Bdellovibrio to degrade the prey's PHA. Predator motility was higher when growing on PHA accumulating prey. External addition of PHA polymer (latex suspension) to Bdellovibrio preying on the PHA minus mutant P. putida KT42C1 restored predator movement, suggesting that PHA is a key prey component to sustain predator swimming speed. High velocities observed in Bdellovibrio preying on the PHA producing strain were correlated to high intracellular ATP levels of the predator. These effects brought Bdellovibrio fitness benefits as predation on PHA producers was more efficient than predation on non‐producing bacteria.
Vfm a new quorum sensing system controls the virulence of Dickeya dadantii
Authors: Nasser William , Dorel Corinne , Wawrzyniak Julien , Van Gijsegem Frédérique , Groleau Marie‐Christine , Déziel Eric , Reverchon Sylvie
Published: November 2012

Dickeya dadantii is a plant pathogen that secretes cell wall‐degrading enzymes (CWDE) that are responsible for soft‐rot symptoms. Virulence genes are expressed in a concerted manner and culminate when bacterial multiplication slows. We identify a 25 kb vfm cluster required for D. dadantii CWDE production and pathogenesis. The vfm cluster encodes proteins displaying similarities both with enzymes involved in amino acid activation and with enzymes involved in fatty acid biosynthesis. These similarities suggest that the vfm genes direct the production of a metabolite. Cell‐free supernatant from the D. dadantii wild‐type strain restores CWDE production in vfm mutants. Collectively, our results indicate that vfm genes direct the synthesis of an extracellular signal and constitute a new quorum sensing system. Perception of the signal is achieved by the two‐component system VfmH–VfmI, which activates the expression of the vfmE gene encoding an AraC regulator. VfmE then activates both the transcription of the CWDE genes and the expression of the vfm operons. The vfm gene cluster does not seem to be widespread among bacterial species but is conserved in other Dickeya species and could have been laterally transferred to Rahnella. This work highlights that entirely new families of bacterial languages remain to be discovered.
Endoscopic papillary large‐balloon dilation following limited sphincterotomy for the removal of refractory bile duct stones: Experience of 169 cases in a single Chinese center
Authors: Yang Xiao Ming , Hu Bing , Pan Ya Min , Gao Dao Jian , Wang Tian Tian , Wu Jun , Ye Xin
Published: November 2012

Objective

To evaluate the efficacy and safety of endoscopic papillary large‐balloon dilation (EPLBD) combined with limited endoscopic sphincterotomy (EST) for the removal of large biliary duct stones (≥10 mm).

Methods

Data of patients who underwent an attempted removal of large bile duct stones by limited EST followed by EPLBD (≥12 mm in diameter) from April 2006 to October 2011 in our center were reviewed. Clinical characteristics, endoscopic methods and outcomes of the patients were collected and analyzed.

Results

A total of 169 patients with a mean age of 69.3 years (range 19–97 years) underwent 171 procedures. Median stone size and balloon diameter was 15 mm and 13 mm, respectively. Complete stone removal in a single session was achieved in 163 procedures (95.3%) with mechanical lithotripsy (ML) used in 66 (38.6%). Patients with a larger stone size required more frequent use of ML with a comparable success rate (P < 0.01). There were no significant differences between patients with and without periampullary diverticula in stone clearance (97.3% vs 93.8%), ML requirement (36.5% vs 40.2%) and complications (2.7% vs 6.2%) (all P > 0.05). Seven patients had eight procedure‐related complications including moderate or mild bleeding (n = 4), minor perforation (n = 1), mild pancreatitis (n = 2) and cholangitis (n = 1).

Conclusion

EPLBD following limited EST is an effective and safe approach for the removal of large biliary duct stones, especially for those refractory cases.
Improving rigour and efficiency of use‐availability habitat selection analyses with systematic estimation of availability
Authors: Benson John F.
Published: November 2012

Animal habitat selection analyses often rely on comparisons of habitat use and availability to infer selection. Random locations are commonly used to assess availability despite inefficiency and potential uncertainty associated with random sampling. Herein, I propose a systematic approach to estimate habitat availability to reduce sampling error and computing time associated with GIS‐based estimation of habitat availability using random locations.

I used Euclidean distance analysis (EDA) as a model technique to demonstrate the sensitivity of use‐availability analyses to insufficient random sampling and to evaluate the proposed systematic approach. I re‐analysed data from a previous study of habitat selection of Florida panthers (Puma concolor coryi) and compared results of analyses in which distance‐based habitat availability (i.e. expected distance) was estimated with a range in sample sizes of random locations, and also systematically.

My results demonstrate that expected distances and statistical results of EDA based on random sampling can be unreliable with low and arbitrary numbers of random points, vary if increasing numbers of points are used, and approach results obtained systematically at greater numbers of points (i.e. with sufficient sampling).

The systematic approach efficiently measures habitat availability by making calculations from all possible locations, at a specified resolution, across the scale of interest. Thus, it eliminates uncertainty due to sampling error and is considerably faster. The systematic approach improves rigour and efficiency of animal habitat selection analyses that rely on comparisons of habitat use and availability and ensures repeatability of results for practical and theoretical applications.
Intensive buffering can keep pH above 7.2 for over 4 h during apnea: an experimental porcine study
Authors: HÖSTMAN S. , ENGSTRÖM J. , HEDENSTIERNA G. , LARSSON A.
Published: November 2012

Background

Ventilation with low tidal volumes reduces mortality in acute respiratory distress syndrome. A further reduction of tidal volumes might be beneficial, and it is known that apneic oxygenation (no tidal volumes) with arteriovenous CO2 removal can keep acid‐base balance and oxygenation normal for at least 7 h in an acute lung injury model. We hypothesized that adequate buffering might be another approach and tested whether tris‐hydroxymethyl aminomethane (THAM) alone could keep pH at a physiological level during apneic oxygenation for 4 h.

Methods

Six pigs were anesthetized, muscle relaxed, and normoventilated. The lungs were recruited, and apneic oxygenation as well as administration of THAM, 20 mmol/kg/h, was initiated. The experiment ended after 270 min, except one that was studied for 6 h.

Results

Two animals died before the end of the experiment. Arterial pH and arterial carbon dioxide tension (PaCO2) changed from 7.5 (7.5, 7.5) to 7.3 (7.2, 7.3) kPa, P < 0.001 at 270 min, and from 4.5 (4.3, 4.7) to 25 (22, 28) kPa, P < 0.001, respectively. Base excess increased from 5 (3, 6) to 54 (51, 57) mM, P < 0.001. Cardiac output and arterial pressure were well maintained. The pig, which was studied for 6 h, had pH 7.27 and PaCO2 27 kPa at that time.

Conclusion

With intensive buffering using THAM, pH can be kept in a physiologically acceptable range for 4 h during apnea.
Vital dysfunctions after intensive care discharge: prevalence and impact on patient outcome
Authors: TIRKKONEN J. , OLKKOLA K. T. , HUHTALA H. , TENHUNEN J. , HOPPU S.
Published: November 2012

Background

Patients discharged from the intensive care unit (ICU) are at increased risk for serious adverse events (SAEs). Recording vital functions and comprehending the consequences of altered vitals on general wards may be suboptimal. This potentially endangers recovery after successful intensive care. We aimed to determine the prevalence of vital dysfunctions after ICU discharge and their effect on patient outcome.

Methods

A prospective observational study. Adult patients discharged from a tertiary referral hospital ICU to general wards without treatment limitations were visited 24 h afterwards; their vitals were measured and reported to ward staff. Attending ward nurse responsible for patient was interviewed.

Results

The cohort consisted of 184 patients who had survived the first 24 h on the ward without complications (age: 57 ± 16 years; male: 68%). The prevalence of objectively measured vital dysfunctions was 15%, and the attending nurse had been unusually concerned about the patient in 19% of cases. Of the 184 patients, 9.8% subsequently suffered an SAE. In a multivariate logistic regression model, only vital dysfunctions (odds ratio 3.79; 95% confidence interval 1.18–12.2) and nurse concern (3.63; 1.17–11.3) were independently associated with an increased incidence of SAE. Medical emergency team (MET) assistance was never considered necessary by ward staff. Sensitivity of observed altered vitals on SAEs was 50% and specificity 89%. Sensitivity of nurse concern was 26%, specificity 84%.

Conclusions

Simple vital function measurement and attending ward nurse's subjective assessment facilitate early detection of post‐ICU patients at risk. The threshold in seeking assistance through MET remains high.
PaO2 oscillations caused by cyclic alveolar recruitment can be monitored in pig buccal mucosa microcirculation
Authors: KLEIN K. U. , HARTMANN E. K. , BOEHME S. , SZCZYRBA M. , HEYLEN L. , LIU T. , DAVID M. , WERNER C. , MARKSTALLER K. , ENGELHARD K.
Published: November 2012

Background

Cyclic alveolar recruitment and derecruitment play a role in the pathomechanism of acute lung injury and may lead to arterial partial pressure of oxygen (PaO2) oscillations within the respiratory cycle. It remains unknown, however, if these PaO2 oscillations are transmitted to the microcirculation. The present study investigates if PaO2 oscillations can be detected in the pig buccal mucosa microcirculation.

Methods

Respiratory failure was induced by surfactant depletion in seven pigs. PaO2 oscillations caused by cyclic recruitment and derecruitment were measured in the thoracic aorta by fast fluorescence quenching of oxygen technology. Haemoglobin oxygen saturation, haemoglobin amount and blood flow in the buccal mucosa microcirculation were determined by combined fast white light spectrometry and laser Doppler flowmetry additionally to systolic arterial pressure. Measurements were performed during baseline conditions and during cyclic recruitment and derecruitment.

Results

Measurements remained stable during baseline. Respiratory‐dependent oscillations occurred in the systemic circulation [PaO2 oscillations 92 (69–172) mmHg; systolic arterial pressure oscillations 33 (13–35) %] and were related to the respiratory rate (5.0 ± 0.2/min) as confirmed by Fourier analysis. Synchronised oscillations were detected to the pig buccal mucosa microcirculation [haemoglobin oxygen saturation oscillations 3.4 (2.7–4.9) %; haemoglobin amount oscillations 8.5 (2.3–13.3) %; blood flow oscillations 66 (18–87) %]. The delay between PaO2‐\ and microcirculatory oxygen oscillations was 7.2 ± 2.8 s.

Conclusion

The present study suggests that PaO2 oscillations caused by cyclic recruitment and derecruitment were transmitted to the buccal mucosa microcirculation. This non‐invasive approach of measuring oxygen waves as a surrogate parameter of cyclic recruitment and derecruitment could be used to monitor PaO2 oscillations at the bedside.
Phasic transition from goal‐directed to habitual control over drug‐seeking produced by conflicting reinforcer expectancy
Authors: Hogarth Lee , Field Matt , Rose Abigail K.
Published: November 2012

The transition from goal‐directed to habitual control over drug‐seeking has been experimentally demonstrated in animals, but there have been no comparable reports in humans. Following a recent animal design, the current study employed an outcome‐devaluation procedure to test whether goal‐directed control over tobacco seeking would be abolished by alcohol expectancy. Eighty smokers first learned that two responses earned tobacco or chocolate points, respectively, before tobacco was devalued by health warnings and smoking satiety. Participants were then presented with either a glass of beer/wine or water with instructions that this item could be consumed after the task (alternative reward). Then choice between the tobacco and chocolate response was measured in extinction to assess goal‐directed control of tobacco seeking, in a nominal Pavlovian to instrumental transfer (PIT) test to assess stimulus control of tobacco seeking, and in a reacquisition test to assess the impact of direct feedback from the outcomes. The results showed that alcohol expectancy selectively abolished goal‐directed control of tobacco seeking but not stimulus control or the impact of feedback from outcomes. These data suggest that ‘endogenous’ retrieval of low drug value governing goal‐directed regulation of drug seeking is disrupted by conflicting appraisal of an alternative reinforcer, promoting habitual control, which may play a role in relapse.
Association between single nucleotide polymorphism of PD‐L1 gene and non‐small cell lung cancer susceptibility in a Chinese population
Authors: Chen Yan‐bin , Mu Chuan‐yong , Chen Cheng , Huang Jian‐An
Published: November 2012

Aim

To evaluate the correlation between a polymorphism of PD‐L1 gene and the susceptibility of non‐small cell lung cancer (NSCLC) in a Chinese population.

Methods

A total of 293 Chinese patients with NSCLC and 293 age and sex matched controls of the same ethnic origin were enrolled in this study. A/C polymorphism at position 8923 in intron 4 of PD‐L1 gene was typed using the polymerase chain reaction‐restriction fragment length polymorphism method (PCR‐RFLP). The interactions between A/C genotype, allele frequency and NSCLC susceptibility were analyzed.

Results

The A/C genotype frequencies were significantly different between NSCLC patients and controls. The AC and CC frequencies were higher in NSCLC patients than in controls (16.4 vs 8.9%, 1.0 vs 0.3%, respectively). The C‐allele frequency was higher in NSCLC patients than in controls (9.2 vs 4.8%). Significant differences in the A and C allele frequencies were noted between the two groups (χ2 = 8.864, P = 0.003). More risk of NSCLC was found in individuals carrying the C allele than in those carrying the A allele (OR = 2.203; 95% CI 1.262–3.242). In both light smokers (≤20 pack‐years) and heavy smokers (>20 pack‐years), individuals carrying the C‐allele had more risk of NSCLC than those carrying the A‐allele (light smokers OR = 1.847, 95% CI 1.001–3.409; heavy smokers OR = 3.252, 95% CI 1.196–8.845, respectively).

Conclusion

An A/C polymorphism at position 8923 in the PD‐L1 gene is associated with NSCLC susceptibility. The PD‐L1 polymorphism plays a role in NSCLC, especially in patients with the C‐allele.
Differential relations between fronto‐limbic metabolism and executive function in patients with remitted bipolar I and bipolar II disorder
Authors: Li Cheng‐Ta , Hsieh Jen‐Chuen , Wang Shyh‐Jen , Yang Bang‐Hung , Bai Ya‐Mei , Lin Wei‐Chen , Lan Chen‐Chia , Su Tung‐Ping
Published: November 2012

Li C‐T, Hsieh J‐C, Wang S‐J, Yang B‐H, Bai Y‐M, Lin W‐C, Lan C‐C, Su T‐P. Differential relations between fronto‐limbic metabolism and executive function in patients with remitted bipolar I and bipolar II disorder.  Bipolar Disord 2012: 14: 831–842. © 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

Objectives: The aim of this study was to investigate the relationship between resting brain glucose metabolism and cognitive profiles in patients with remitted bipolar I disorder (BD‐I) and bipolar II disorder (BD‐II). We hypothesized that BD‐I patients (compared to BD‐II patients) would perform worse on tests of cognitive function because of abnormal metabolism in the prefrontal cortex and other mood‐related brain areas.

Methods:  Thirty‐four patients with remitted bipolar disorder (BD) (BD‐I = 17, BD‐II = 17) under treatment and 17 well‐matched healthy controls received both fluorodeoxyglucose (18F‐FDG) positron emission tomography (PET) and neuropsychological tests of attention, memory, and executive function.

Results:  Clinical features in patients with BD‐I and BD‐II were comparable. Executive function, as indicated by performance on the Wisconsin Card Sorting Test, was significantly worse (i.e., higher percentage of errors, lower percentage of conceptual level responses, and fewer categories completed) in BD‐I patients than in BD‐II patients and healthy subjects. No difference in attention and memory tests was found among these three groups. Brain PET analysis showed that BD‐I patients (compared to BD‐II patients) had significantly lower glucose uptake in the bilateral anterior cingulum, insula, striatum, and part of the prefrontal cortex, and higher glucose uptake in the left parahippocampus. Further analyses revealed significant correlations between poor executive function and abnormal glucose uptake in other brain areas in BD‐I patients.

Conclusions:  There are neurobiological differences between subtypes of BD. BD‐I is associated with more impaired fronto‐limbic circuitry, which might account for reduced executive function in BD‐I patients during remission.
Glycogen synthase kinase‐3 levels and phosphorylation undergo large fluctuations in mouse brain during development
Authors: Beurel Eléonore , Mines Marjelo A , Song Ling , Jope Richard S
Published: November 2012

Beurel E, Mines MA, Song L, Jope RS. Glycogen synthase kinase‐3 levels and phosphorylation undergo large fluctuations in mouse brain during development.  Bipolar Disord 2012: 14: 822–830. © 2012 John Wiley & Sons A/S.Published by Blackwell Publishing Ltd.

Objectives:  Dysregulated glycogen synthase kinase‐3 (GSK3) may contribute to the pathophysiology of mood disorders and other diseases, and appears to be a target of certain therapeutic drugs. The growing recognition of heightened vulnerability during development to many psychiatric diseases, including mood disorders, led us to test if there are developmental changes in mouse brain GSK3 and its regulation by phosphorylation and by therapeutic drugs.

Methods:  GSK3 levels and phosphorylation were measured at seven ages of development in the mouse cerebral cortex and hippocampus.

Results:  Two periods of rapid transitions in GSK3 levels were identified: a large rise between postnatal days 1 and 2 and three weeks of age, where GSK3 levels were as much as fourfold higher than adult mouse brain levels, and a rapid decline between 2–4 and eight weeks of age, when adult levels were reached. Inhibitory serine‐phosphorylation of GSK3, particularly GSK3β, was extremely high in the one‐day postnatal mouse brain, and rapidly declined thereafter. These developmental changes in GSK3 were equivalent in the male and female cerebral cortex, and differed from other signaling kinases, including Akt, extracellular‐regulated kinases 1/2, c‐Jun N‐terminal kinase, and p38 levels and phosphorylation. In contrast to the adult mouse brain, where administration of lithium or fluoxetine rapidly and robustly increased serine‐phosphorylation of GSK3, in young mice these responses were blunted or absent.

Conclusions:  High brain levels of GSK3 and large fluctuations in its levels and phosphorylation in the juvenile and adolescent mouse brain raise the possibility that they may contribute to destabilized mood regulation induced by environmental and genetic factors.
ADHD comorbidity can matter when assessing cortical thickness abnormalities in patients with bipolar disorder
Authors: Hegarty Catherine E , Foland‐Ross Lara C , Narr Katherine L , Sugar Catherine A , McGough James J , Thompson Paul M , Altshuler Lori L
Published: November 2012

Hegarty CE, Foland‐Ross LC, Narr KL, Sugar CA, McGough JJ, Thompson PM, Altshuler LL. ADHD comorbidity can matter when assessing cortical thickness abnormalities in patients with bipolar disorder.  Bipolar Disord 2012: 14: 843–855. © 2012 John Wiley & Sons A/S.Published by Blackwell Publishing Ltd.

Objectives: Attention‐deficit hyperactivity disorder (ADHD) is prevalent in patients with bipolar disorder (BP), but very few studies consider this when interpreting magnetic resonance imaging findings. No studies, to our knowledge, have screened for or controlled for the presence of ADHD when examining cortical thickness in patients with BP. We used a 2 × 2 design to evaluate the joint effects of BP and ADHD on cortical thickness and uncover the importance of ADHD comorbidity in BP subjects.

Methods: The study included 85 subjects: 31 healthy controls, 17 BP‐only, 19 ADHD‐only, and 18 BP/ADHD. All patients with BP were subtype I, euthymic, and not taking lithium. Groups did not differ significantly in age or gender distribution. We used cortical thickness measuring tools combined with cortical pattern matching methods to align sulcal/gyral anatomy across participants. Significance maps were used to check for both main effects of BP and ADHD and their interaction. Post‐hoc comparisons assessed how the effects of BP on cortical thickness varied as a function of the presence or absence of ADHD.

Results: Interactions of BP and ADHD diagnoses were found in the left subgenual cingulate and right orbitofrontal cortex, demonstrating that the effect of BP on cortical thickness depends on ADHD status.

Conclusions: Some brain abnormalities attributed to BP may result from the presence of ADHD. Diagnostic interactions were found in regions previously implicated in the pathophysiology of BP, making it vital to control for an ADHD comorbid diagnosis when attempting to isolate neural or genetic abnormalities specific to BP.
The ethics of talent management
Authors: Swailes Stephen
Published: November 2012

Organisational approaches to talent management are often concerned with the ways that a small proportion of relatively high‐performing employees are identified and managed in relation to the majority. Despite a growing literature on talent management, no papers have provided any guidance on how to evaluate it from an ethical standpoint. After considering what is meant by talent, this paper considers the ethical issues that arise from the operation of talent management programmes. These considerations are then used to create a framework that has the potential to influence the practical design of talent programmes and which may focus further debate into the ethics of talent management.