bluuebunny/crossref_metadata_2025 huggingface dataset:
Perinatal overnutrition and the programming of food preferences: pathways and mechanisms
Authors: Ong Z. Y. , Gugusheff J. R. , Muhlhausler B. S.
Published: May 2012

One of the major contributing factors to the continuous rise in obesity rates is the increase in caloric intake, which is driven to a large extent by the ease of access and availability of palatable high-fat, high-sugar ‘junk foods’. It is also clear that some individuals are more likely to overindulge in these foods than others; however, the factors that determine an individual's susceptibility towards the overconsumption of palatable foods are not well understood. There is growing evidence that an increased preference for these foods may have its origins early in life. Recent work from our group and others has reported thatin uteroand early life exposure to these palatable foods in rodents increased the offspring's preference towards foods high in fat and sugar. One of the potential mechanisms underlying the programming of food preferences is the altered development of the mesolimbic reward system, a system that plays an important role in driving palatable food intake in adults. The aim of this review is to explore the current knowledge of the programming of food preferences, a relatively new and emerging area in the DOHAD field, with a particular focus on maternal overnutrition, the development of the mesolimbic reward system and the biological mechanisms which may account for the early origins of an increased preference for palatable foods.
Pore fluid pressure diffusion in defluidizing granular columns
Authors: Montserrat S. , Tamburrino A. , Roche O. , Niño Y.
Published: May 2012

Pore fluid pressure variations play an important role in the motion of natural granular flows like debris and pyroclastic flows. Pore pressure in a defluidizing air‐particle bed was investigated by means of experiments and numerical modeling. Experiments consisted of recording the defluidization process, measured as the decay of the basal pore fluid pressure in initially aerated granular mixtures. Mixtures were aerated to different degrees of fluidization by introducing a vertical air flux at the base of a granular column. The degree of fluidization was characterized by the parameter βo (pore fluid pressure/lithostatic pressure). Bed expansion occurred for βo > 0.8–0.9, with maximum expansions near 8% at βo ∼1. Pore pressure diffusion in our mixtures was modeled by a simple diffusion equation, taking into account a variable diffusion coefficient. When mixtures were expanded (βo > 0.8–0.9), continuous consolidation introduced nonlinearities in the diffusion coefficients, which retarded the decay of pore pressure. In contrast, for non‐expanded mixtures, the diffusion coefficient remained constant (linear diffusion). Our results highlight that mixture compressibility can effectively reduce the pressure diffusion coefficient in initially expanded granular mixtures, thus increasing the duration of pressure diffusion. In our experiments, as well as for most self‐consolidating natural granular mixtures, changes in permeability due to mixture consolidation appear to be negligible for the defluidizing process, as they are counteracted by changes in porosity and because the fluid behaves as incompressible, even when the fluid is air.
Spectacular lightning revealed in 2009 Mount Redoubt eruption
Authors: Behnke Sonja A. , Thomas Ronald J. , Krehbiel Paul R. , McNutt Stephen R.
Published: May 2012

The explosive eruption of Alaska's Mount Redoubt volcano in March and April 2009 provided a superb opportunity for studying volcanic lightning. The energetic explosions produced powerful volcanic lightning storms, the largest of which rivaled the intensity of the massive supercell thunderstorms that frequent the midwestern Great Plains. Although lightning often has been observed in the plumes of explosive volcanic eruptions, only a handful of detailed studies have delved into the origins of volcanic lightning. Active volcanoes tend to be situated in remote locations, where they are difficult to observe, and often have sudden, unpredicted eruptions. Even when the eruptions are observed close at hand, the volcanic clouds are intensely opaque, obscuring most of the lightning from view.
Evidence for P′P′ asymmetrical scattering at near podal distances
Authors: Wu Wenbo , Ni Sidao , Zeng Xiangfang
Published: May 2012

We report strong short period (0.5–1.2 Hz) precursors to P′P′df at podal to short distances (0–50°) with advance time around 60s. From FK analysis, we find that the precursors at epicentral distance of ∼35° arrive along back‐azimuth about +/−120° off the great circle paths (asymmetrical path) with slowness between 2–4 sec/deg, arguing against propagation path in the inner core. Polarization analysis also supports wave propagation in the outer core. Timing and shape of the precursors' waveform envelopes are well matched with synthetic envelopes taking into account the scattering from the rough free surface and volumetric heterogeneities inside the Earth along asymmetrical propagation path. Therefore the precursors are very probably generated with asymmetrical scattering mechanism. This interpretation does not require extra discontinuities or a layer of strong small scale heterogeneities in the upper mantle, which are inferred from P′P′ precursors when only symmetrical scattering is assumed.
Boundary‐layer turbulence characteristics during aeolian saltation
Authors: Li Bailiang , McKenna Neuman Cheryl
Published: May 2012

A great deal of effort has been expended in measuring turbulence phenomena in clean air flows. However, no previous measurements have been successfully made of the vertical distributions of turbulence intensity and Reynolds stress in a fully adjusted boundary‐layer flow saturated with saltating particles. The present wind tunnel study addresses this knowledge gap using a custom designed laser‐Doppler anemometer (LDA). The amount of turbulence is found to increase with the introduction of saltating particles to the airflow. Over the lowest 15% of boundary layer, vertical profiles of the streamwise wind speed provide friction velocities that lie well within the narrow range of those derived from direct measurement of the Reynolds stress. Relative to clean air, aeolian saltation is demonstrated to increase the magnitude but not the frequency of burst‐sweep events that primarily contribute to the total fluid stress. Within several millimeters above the bed surface, all vertical profiles of wind speed converge upon a focal point, as the local fluid stress declines toward the mobile bed.
Using models and satellite observations to evaluate the strength of snow albedo feedback
Authors: Fletcher Christopher G. , Zhao Hongxu , Kushner Paul J. , Fernandes Richard
Published: May 2012

Snow albedo feedback (SAF) is important for global climate change, with strong regional impacts over northern continental areas. SAF calculated from the seasonal cycle is a good predictor of SAF in climate change among a suite of coupled climate models. A previous linear decomposition of the simulated total SAF (NET) found 80% was related to the albedo contrast of snow covered and snow‐free land (SNC), and 20% was related to the temperature dependence of snow albedo (TEM). By contrast, recent work using snow cover and surface albedo derived from APP‐x satellite observations found that TEM and SNC contributed almost equally to NET. In the present study, revised estimates of TEM and SNC for northern land areas are calculated for the period 1982–99 using a simplified and reproducible method for comparing SAF in models and observations. The observed NET is −1.11% K−1, of which 69% comes from SNC and 31% from TEM; the approximate additivity of SNC and TEM indicates that these two terms fully explain the total SAF. Regionally, the SNC term dominates equatorward of 65°N, while TEM dominates over the Arctic. The mean of 17 CMIP3 climate models shows NET is 7% larger than observed, caused primarily by a bias in TEM equatorward of 65°N. A newer model (NCAR CCSM4) with improved land surface and snow schemes reproduces observed values of NET and SNC closely. However, TEM in all models examined is 50–100% weaker than observed over the Arctic. There is a strong correlation between SAF in the seasonal cycle and SAF in climate change for all components, but the correlation is weakest for TEM. The TEM term also exhibits a much larger spread in the seasonal cycle than in climate change, which partially explains a discrepancy between previous published studies examining TEM.
On spectroscopic models of the O2A‐band and their impact upon atmospheric retrievals
Authors: Long David A. , Hodges Joseph T.
Published: May 2012

Highly accurate spectroscopic models for O2 A‐band [b1Σg+ ← X3Σg−(0,0)] absorption are required in numerous satellite‐ and ground‐based remote sensing measurements of atmospheric greenhouse gases. In this study, we quantify the sensitivity of the calculatedA‐band transmission spectrum to the choice of line profile and model‐input line parameter data. The models considered include the Voigt and Galatry profiles for the individualA‐band transitions as well as line mixing and collision‐induced absorption. In order of increasing relative importance, we show that measurement uncertainty is influenced by: available line parameter data, Dicke narrowing, line mixing, and collision‐induced absorption effects.
Replication‐mediated disassociation of replication protein A—XPA complex upon DNA damage: implications for RPA handing off
Authors: Jiang Gaofeng , Zou Yue , Wu Xiaoming
Published: May 2012

RPA (replication protein A), the eukaryotic ssDNA (single‐stranded DNA)‐binding protein, participates in most cellular processes in response to genotoxic insults, such as NER (nucleotide excision repair), DNA, DSB (double‐strand break) repair and activation of cell cycle checkpoint signalling. RPA interacts with XPA (xeroderma pigmentosum A) and functions in early stage of NER. We have shown that in cells the RPA—XPA complex disassociated upon exposure of cells to high dose of UV irradiation. The dissociation required replication stress and was partially attributed to tRPA hyperphosphorylation. Treatment of cells with CPT (camptothecin) and HU (hydroxyurea), which cause DSB DNA damage and replication fork collapse respectively and also leads to the disruption of RPA—XPA complex. Purified RPA and XPA were unable to form complex in vitro in the presence of ssDNA. We propose that the competition‐based RPA switch among different DNA metabolic pathways regulates the dissociation of RPA with XPA in cells after DNA damage. The biological significances of RPA—XPA complex disruption in relation with checkpoint activation, DSB repair and RPA hyperphosphorylation are discussed.
Contribution of murine bone marrow mesenchymal stem cells to pancreas regeneration after partial pancreatectomy in mice
Authors: Han Fei , Wang Chun‐You , Yang Li , Zhan Su‐Dong , Zhang Meng , Tian Kui
Published: May 2012

The implantation of BMSCs (bone marrow mesenchymal stem cells) has emerged as a potential method of treating tissue damage, but the in vivo differentiation of BMSCs in an injured pancreas and its therapeutic effects have not been determined. Our aim has been to investigate the potential of BMSCs to contribute to the parenchyma and mesenchymal components of the pancreas during rapid regeneration, with preliminary exploration of the molecular mechanisms of this process. GFP+ (green fluorescent protein+) BMSCs were intravenously infused into the tail veins of mice that had received a 65–70% partial pancreatectomy, while mice that had only received a partial pancreatectomy and mice that had only been injected with BMSCs served as controls. Four weeks later, the injected GFP+ BMSCs were diffusely engrafted in the pancreatic parenchyma and mesenchyma of the recipient mice with pancreatic injuries and had differentiated into pancreatic ductal epithelial cells (accounting for 1.7±0.3%), vascular endothelial cells (3.2±0.6%) and PSCs (pancreatic stellate cells) (5.2±1.6%), but no β or neural cells. Significantly, more engrafted and differentiated GFP+ BMSCs were observed in the regenerating pancreas than in the normal pancreas. For the mice that received a partial pancreatectomy, the pancreatic weight/body weight of the mice with BMSC treatment was greater than mice without BMSC treatment (P<0.05). In addition, real‐time RT—PCR (reverse transcription—PCR) showed that the expression levels of miR‐9 (microRNA 9) and miR‐204 in the engrafted BMSCs (5.2‐ and 2.6‐fold, P<0.05, respectively) were increased compared with wild‐type BMSCs. We also observed a significant reduction in the expression of miR‐375 (0.71‐fold, P<0.05) in engrafted GFP+ BMSCs compared with wild‐type BMSCs. BMSCs can therefore be a potential cell bank for treating pancreatic injuries by contributing to a variety of cell types. This process might be related to the expression of miR‐9, miR‐204 and miR‐375.
On Lagrangian single-particle statistics
Authors: Falkovich Gregory , Xu Haitao , Pumir Alain , Bodenschatz Eberhard , Biferale Luca , Boffetta Guido , Lanotte Alessandra S. , Toschi Federico ,   (International Collaboration for Turbulence Research)
Published: May 2012

In turbulence, ideas of energy cascade and energy flux, substantiated by the exact Kolmogorov relation, lead to the determination of scaling laws for the velocity spatial correlation function. Here we ask whether similar ideas can be applied to temporal correlations. We critically review the relevant theoretical and experimental results concerning the velocity statistics of a single fluid particle in the inertial range of statistically homogeneous, stationary and isotropic turbulence. We stress that the widely used relations for the second structure function, D2(t) ≡ ⟨[v(t) − v(0)]2⟩∝εt, relies on dimensional arguments only: no relation of D2(t) to the energy cascade is known, neither in two- nor in three-dimensional turbulence. State of the art experimental and numerical results demonstrate that at high Reynolds numbers, the derivative \documentclass[12pt]{minimal}\begin{document}$\frac{d D_2(t)}{dt}$\end{document}dD2(t)dt has a finite non-zero slope starting from t ≈ 2τη. The analysis of the acceleration spectrum ΦA(ω) indicates a possible small correction with respect to the dimensional expectation ΦA(ω) ∼ ω0 but present data are unable to discriminate between anomalous scaling and finite Reynolds effects in the second order moment of velocity Lagrangian statistics.
Optical and acoustic phonon modes in strained InGaAs/GaAs rolled up tubes
Authors: Angelova T. , Shtinkov N. , Ivanov Ts. , Donchev V. , Cantarero A. , Deneke Ch. , Schmidt O. G. , Cros A.
Published: May 2012

Rolled-up semiconductor tubes of various diameters made of alternating In0.215Ga0.785As/GaAs layers have been investigated by means of Raman scattering. The optical and acoustic phonon modes of individual tubes have been studied and compared with the characteristics of the surrounding material. After tube formation, the frequency of the phonon modes shifts with respect to the as-grown material and disorder activated modes are observed. The frequency shifts are related to the residual strain in the tubes through the deformation potential approximation. Good agreement with atomistic valence force field simulations and x-ray micro-diffraction measurements is found. By comparison with x-ray data, a Raman strain constant K = 0.65 is proposed for In0.215Ga0.785As. In the low frequency range, acoustic mode doublets are observed on the tubes that are absent in the surrounding material. They show clear evidence of the formation of periodic superlattices after the rolling-up process, and give insight into the quality of their interfaces.
Thermal conductivity of Ce1−xLaxCu4Al Kondo alloys
Authors: Falkowski M. , Kowalczyk A.
Published: May 2012

Experimental results of thermal conductivity (κ) for Ce1−xLaxCu4Al alloy series are reported. The hexagonal CeCu5-type structure was confirmed by the powder X-ray diffraction technique. The measured thermal conductivity increases with increasing temperature. The reduced Lorentz number L/L0 of Ce1−xLaxCu4Al increases with cooling and reaches a maximum value at low temperatures. The magnetic contribution to the thermal resistivity Wmag was separated, and it was shown that the product WmagT has a logT-behavior, suggesting of Kondo effect. The log T-behavior for the WmagT is quite similar to that observed as for magnetic resistivity ρmag.
About excitation of surface plasma waves by elliptical relativistic electron beam in a magnetized dusty plasma column with elliptical cross section
Authors: Abdoli-Arani A. , Jazi B.
Published: May 2012

The surface plasma waves in a magnetized dusty plasma elliptical cylinder driven by elliptic relativistic electron beam propagating inside the elliptical cylinder are studied. The dispersion relation of surface plasma waves has been retrieved from the derived dispersion relation by considering that the beam is absent and there is no dust in the plasma cylinder. Mathematically, it is shown that the beam can interact with the surface plasma waves via Cerenkov interaction and fast cyclotron interaction. The growth rate and phase velocity in every cases are obtained. Finally, the numerical results and graphs are presented.
Effect of nonthermal electrons on oblique electrostatic excitations in a magnetized electron-positron-ion plasma
Authors: Alinejad H.
Published: May 2012

The linear and nonlinear propagation of ion-acoustic waves are investigated in a magnetized electron-positron-ion (e-p-i) plasma with nonthermal electrons. In the linear regime, the propagation of two possible modes and their evolution are studied via a dispersion relation. In the cases of parallel and perpendicular propagation, it is shown that these two possible modes are always stable. Then, the Korteweg-de Vries equation describing the dynamics of ion-acoustic solitary waves is derived from a weakly nonlinear analysis. The influence on the solitary wave characteristics of relevant physical parameters such as nonthermal electrons, magnetic field, obliqueness, positron concentration, and temperature ratio is examined. It is observed that the increasing nonthermal electrons parameter makes the solitary structures much taller and narrower. Also, it is revealed that the magnetic field strength makes the solitary waves more spiky. The present investigation contributes to the physics of the nonlinear electrostatic ion-acoustic waves in space and laboratory e-p-i plasmas in which wave damping produces an electron tail.
Geometric-shape-dependent structural transition behavior in (110) SrRuO3 epitaxial thin films
Authors: Kan Daisuke , Shimakawa Yuichi
Published: May 2012

We performed structural investigations of epitaxially grown SrRuO3 films with geometric shapes of one-dimensional stripes and a two-dimensional layer, focusing on how the geometric shapes affect the structural transition behavior from the high-temperature pseudo-cubic phase to the low-temperature orthorhombic one. From the temperature dependence of the out-of-plane lattice parameter of the films, we found that the structural transition in the stripe-shape film occurs in a narrower temperature range as compared to that in the layer-shape film. Detailed reciprocal space mappings reveal that in the stripe-shape film, crystallographic twins are formed in the orthorhombic phase due to the strain relaxation along the [1-10]ortho_SRO direction and as a consequence the transition occurs in the narrower temperature range. In contrast, the layer-shape film is fully strained and maintains a single crystallographic domain across the transition. The results indicate that the strain effect on the structural transition behavior is strongly dependent on the geometric shapes of the films.
Development of a simultaneous Hugoniot and temperature measurement for preheated-metal shock experiments: Melting temperatures of Ta at pressures of 100 GPa
Authors: Li Jun , Zhou Xianming , Li Jiabo , Wu Qiang , Cai Lingcang , Dai Chengda
Published: May 2012

Equations of state of metals are important issues in earth science and planetary science. A major limitation of them is the lack of experimental data for determining pressure-volume and temperature of shocked metal simultaneously. By measuring them in a single experiment, a major source of systematic error is eliminated in determining from which shock pressure release pressure originates. Hence, a non-contact fast optical method was developed and demonstrated to simultaneously measure a Hugoniot pressure-volume (PH-VH) point and interfacial temperature TR on the release of Hugoniot pressure (PR) for preheated metals up to 1000 K. Experimental details in our investigation are (i) a Ni–Cr resistance coil field placed around the metal specimen to generate a controllable and stable heating source, (ii) a fiber-optic probe with an optical lens coupling system and optical pyrometer with ns time resolution to carry out non-contact fast optical measurements for determining PH-VH and TR. The shock response of preheated tantalum (Ta) at 773 K was investigated in our work. Measured data for shock velocity versus particle velocity at an initial state of room temperature was in agreement with previous shock compression results, while the measured shock data between 248 and 307 GPa initially heated to 773 K were below the Hugoniot evaluation from its off-Hugoniot states. Obtained interfacial temperatures on release of Hugoniot pressures (100–170 GPa) were in agreement with shock-melting points at initial ambient condition and ab initio calculations of melting curve. It indicates a good consistency for shock melting data of Ta at different initial temperatures. Our combined diagnostics for Hugoniot and temperature provides an important approach for studying EOS and the temperature effect of shocked metals. In particular, our measured melting temperatures of Ta address the current controversy about the difference by more than a factor of 2 between the melting temperatures measured under shock and those measured in a laser-heated diamond anvil cell at ∼100 GPa.
Terahertz current oscillations in a gated two-dimensional electron gas with antenna integrated at the channel ends
Authors: Di Gaspare Alessandra , Casini Roberto , Foglietti Vittorio , Giliberti Valeria , Giovine Ennio , Ortolani Michele
Published: May 2012

We studied terahertz current oscillations induced by a frequency-tunable radiation source in a AlGaAs/InGaAs/AlGaAs heterostructure field effect transistor channel. A planar antenna was integrated on-chip, and a substrate lens was used for broadband coupling of free-space radiation at 0.18–0.72 THz to the channel ends. Through spectral analysis of the detection signal, we identified two different mixing mechanisms: one related to channel current oscillations and the other to modulation of the gate-to-channel potential. Depending on gate bias and radiation frequency, the two mechanisms either compete or cooperate, leading to responsivity up to 300 V/W and noise equivalent power of 1 nW/Hz0.5
On the characteristic length scales associated with plastic deformation in metallic glasses
Authors: Murali P. , Zhang Y. W. , Gao H. J.
Published: May 2012

Atomistic simulations revealed that the spatial correlations of plastic displacements in three metallic glasses, FeP, MgAl, and CuZr, follow an exponential law with a characteristic length scale ℓc that governs Poisson’s ratio ν, shear band thickness tSB, and fracture mode in these materials. Among the three glasses, FeP exhibits smallest ℓc, thinnest tSB, lowest ν, and brittle fracture; CuZr exhibits largest ℓc, thickest tSB, highest ν, and ductile fracture, while properties of MgAl lie in between those of FeP and CuZr. These findings corroborate well with existing experimental observations and suggest ℓc as a fundamental measure of the shear transformation zone size in metallic glasses.
Controlling flux flow dissipation by changing flux pinning in superconducting films
Authors: Grimaldi G. , Leo A. , Nigro A. , Silhanek A. V. , Verellen N. , Moshchalkov V. V. , Milošević M. V. , Casaburi A. , Cristiano R. , Pace S.
Published: May 2012

We study the flux flow state in superconducting materials characterized by rather strong intrinsic pinning, such as Nb, NbN, and nanostructured Al thin films, in which we drag the superconducting dissipative state into the normal state by current biasing. We modify the vortex pinning strength either by ion irradiation, by tuning the measuring temperature or by including artificial pinning centers. We measure critical flux flow voltages for all materials and the same effect is observed: switching to low flux flow dissipations at low fields for an intermediate pinning regime. This mechanism offers a way to additionally promote the stability of the superconducting state.
Opto-acoustic technique to evaluate adhesion strength of thin-film systems
Authors: Yoshida S. , Adhikari S. , Gomi K. , Shrestha R. , Huggett D. , Miyasaka C. , Park I.
Published: May 2012

An opto-acoustic technique is proposed to evaluate the adhesion strength of thin film systems at the film-substrate interface. The thin-film system to be examined is configured as an end-mirror of a Michelson interferometer, and driven from the rear with an acoustic transducer at audible frequencies. The amplitude of the resultant oscillation of the film is quantified as the variation in the contrast of the interferometric fringe pattern observed with a digital camera at 30 frames/s. As a proof of concept, experiment has been conducted with the use of a pair of strongly and weakly adhered Au-coated Si-wafer specimens. The technique successfully differentiates the adhesion strength of the specimens.
Children with autism encounter an unfamiliar pet
Authors: Grandgeorge Marine , Deleau Michel , Lemonnier Eric , Tordjman Sylvie , Hausberger Martine
Published: May 2012

Autistic disorders are characterized by deficits in social interactions and communication, strong aversion or non-response to social stimuli. However, these children are often reported to develop strong bonds with companion animals. We hypothesized that children with autism (CAD) would present different behavioural profiles when encountering an unfamiliar animal in a Strange Animal Situation close-to-life test. Twenty seven CAD were compared to 59 children with typical development (CTD). Our results. revealed similarities in the behaviour of both groups of children as well as patterns specific to the CAD (e.g. attracted by humans). Different profiles emerged depending on everyday living conditions. This study constitutes, to our knowledge, the first clear description of how children with autism react when encountering an unfamiliar animal and one of the first direct comparisons between CAD and CTD using a naturalistic but standardized setting. Keywords: autism; animal; profile; interaction; ethology
Ecological correlates of song complexity in white-rumped munias
Authors: Kagawa Hiroko , Yamada Hiroko , Lin Ruey-shing , Mizuta Taku , Hasegawa Toshikazu , Okanoya Kazuo
Published: May 2012

Male white-rumped munias sing syntactically simpler songs than their domestic counterparts, Bengalese finches. The differences in song structure may reflect differences in natural selection pressures between wild and domestic environments. Deacon (2010) proposed song simplicity of the wild strain could be subject to natural selection. We hypothesized the selection pressure may be species identification. Thus, we compared song variations in relation to ecological factors and dispersal history of white-rumped munias to understand song evolutionary processes. We found geographic variations of song syntactical complexity. The difference of song syntactical complexity did not corresponded to genetic distance, but did to that of the proportion of mixed flocks with sympatric related species. Birds that inhabited the areas with more mixed flocks sang simpler songs. The song complexity might be constrained to intensify distinct conspecific signals from related species. Our field work provided empirical evidence supporting a proposal made by Deacon (2010). Keywords: birdsong; evolution; masking hypothesis; Bengalese finches; song geographic variation; genetic variation
The Carneades model of argument invention
Authors: Walton Douglas N. , Gordon Thomas F.
Published: May 2012

Argument invention is a method that can be used to help an arguer find arguments that could be used to prove a claim he needs to defend. The aim of this paper is to show how argumentation systems recently developed in artificial intelligence can be applied to the task of argument invention. One such system called Carneades is featured. Carneades can be used to analyze arguments, evaluate arguments, to make an argument diagram, and to construct arguments from a database. Using some simple examples, the paper explains how Carneades works as a system of argument invention.
Participation configuration in a Nigerian university campus
Authors: Odebunmi Akin
Published: May 2012

Studies on participation and spatial orientations of college students have examined aspects of university life, as projected through language, from a reportorial or narrative perspective, but hardly any one of these studies has been devoted exclusively to how students’ participation structure, together with the activities participants orient to at the participation space, evokes shared socio-academic backgrounds and cultural constraints, a major way to gain access into the students’ cognitive and pragmatic tendencies. This research, thus, addresses itself to Nigerian college students’ participation configuration, their participant roles, and the illocutionary goals of their encounters within the Goffmanian participation framework and discourse pragmatic parameters. For data, 100 interactions amongst students of the Faculty of Arts, University of Ibadan, Nigeria, were taped and scrutinised for participation forms and spatial descriptions. Two types of participation structure are manifest in the interactions, namely, unmarked and marked participations. The unmarked participation structure is the regular frame in which Goffman’s ratification and non-ratification framework is strictly observed. The marked participation configuration, an unexpected interactional frame which bifurcates into accommodated and non-accommodated structures, takes interruptions by unaccredited participants as appropriate or inappropriate. The paper contends that participation configuration and contextual elements prescribe participant roles together with the pragmatic functions assigned to language and actions in the interactions. Thus, the illocutionary goals of participants, rooted in socio-academic matters and enabled by participation structures, spatial orientations and body language manipulations are contextually negotiated.
Long‐Term Dynamics of Native and Nonnative Fishes in the San Juan River, New Mexico and Utah, under a Partially Managed Flow Regime
Authors: Gido Keith B. , Propst David L.
Published: May 2012

Nonnative fishes and flow alteration are primary threats to native fish persistence in lotic systems. We used several flow regime attributes and fish sampling data obtained from the San Juan River, New Mexico and Utah, during 1993–2010 to evaluate the potential use of flow manipulations to increase recruitment of native fishes that must cope with nonnative species. During this period, discharge in the river was partially manipulated by reservoir releases that augmented naturally high spring flows in this snowmelt‐driven system. An information theoretic approach was used to rank candidate models that predicted species densities based upon selected combinations of flow attributes and abundances of nonnative species. Autumn density of age‐0 fishes in secondary channels was the main response variable. The main predictor variables included flow attributes associated with interannual variation in daily discharge and water temperature; densities of nonnative competitors; and catch rates of a numerically dominant nonnative predator (the channel catfish Ictalurus punctatus). Top‐ranked models for native species included positive associations with small‐bodied nonnative fishes and negative associations with the abundance of channel catfish adults. Densities of native speckled dace Rhinichthys osculus and flannelmouth suckers Catostomus latipinnis increased with mean spring discharge, but the density of native bluehead suckers C. discobolus did not. With the exception of juvenile channel catfish, the top candidate models predicting densities of nonnative fishes all included the duration of low summer flows. These results confirmed findings from a previous study that demonstrated different responses of native and nonnative fishes to seasonal flows; the present study also revealed that densities of all fishes were generally lower in years with greater abundance of adult channel catfish. Regression analysis indicated that seasonal flow manipulations and suppression of nonnative predator populations could be effective management tools to restore and maintain the native fish community.
STATISTICAL DISCRIMINATION AND EMPLOYERS' RECRUITMENT
Authors: Bonoli Giuliano , Hinrichs Karl
Published: May 2012

This paper deals with the recruitment strategies of employers in the low-skilled segment of the labour market. We focus on low-skilled workers because they are overrepresented among jobless people and constitute the bulk of the clientele included in various activation and labour market programmes. A better understanding of the constraints and opportunities of interventions in this labour market segment may help improve their quality and effectiveness. On the basis of qualitative interviews with 41 employers in six European countries, we find that the traditional signals known to be used as statistical discrimination devices (old age, immigrant status and unemployment) play a somewhat reduced role, since these profiles are overrepresented among applicants for low skill positions. However, we find that other signals, mostly considered to be indicators of motivation, have a bigger impact in the selection process. These tend to concern the channel through which the contact with a prospective candidate is made. Unsolicited applications and recommendations from already employed workers emit a positive signal, whereas the fact of being referred by the public employment office is associated with the likelihood of lower motivation.
Economic Competitiveness of Bio-fuel Production from Underutilized Ethanol Feedstock in Sri Lanka
Authors: Illukpitiya Prabodh , Gopalakrishnan Chennat , Ratnayake R.M.M.B.
Published: May 2012

Sri Lanka's agricultural sector has an abundant supply of natural resources that can be further developed and utilized to produce bio-fuels. Transformation of the nation's significant renewable biomass resources into cost-competitive, high-performance bio-fuels could reduce the country's dependence on imported fossil fuels and enhance energy security. However, there is limited understanding of the potential of bio-fuel resources, their utilization, and economic potential. This study evaluates the economic competitiveness of producing ethanol from sugar, starch and cellulosic feedstock. The net economic returns model was used to select economically feasible feedstock for bio-fuel production. For each feedstock, net present value, feedstock cost per British thermal unit (Btu) and per gallon of ethanol, and break-even price of feedstock and ethanol were calculated. Cellulosic feedstock showed the lowest feedstock cost per gallon of ethanol. Sugarcane, cassava, corn, and cellulosic feedstock appeared to be the leading bio-fuel crops among the investigated crops. For cellulosic feedstock, however, the process of converting the feedstock into ethanol is still in the demonstration phase; hence, results should be interpreted with caution.
Water Transfer Laws and Policies: Tough Questions and Institutional Reform for the Western United States
Authors: Pease Michael
Published: May 2012

Bulk water transfers are complicated by unclear transfer evaluation criteria which intensify the tensions associated with water reallocation. This paper evaluates a series of policy questions associated with water transfer laws and policies. The goal is to outline the tradeoffs between different levels of governmental oversight, with the goal of making the process more consistent and transparent. This paper is focused on the western United States in areas governed by the doctrine of prior appropriations, but the questions apply to semi-arid watersheds across the globe.
Species Specific Recreational Demand: The Case of Trout Fishing in Alberta
Authors: Strong Aaron
Published: May 2012

Many native trout reintroduction programmes and non-native trout suppression programmes are being sold to the public on the fact that through these programmes anglers can catch more and bigger fish. Most studies of recreational demand lump all species within a category of fish into a single species such as lumping rainbow, brook and bull trout into trout. This study disaggregates the effects of individual species on recreational demand. Our goal is to understand the role of species specific characteristics on recreational demand that may or may not be observable. We find that the interaction between angler characteristics and species plays a major role in how anglers choose locations.
Genome‐wide association study of insect bite hypersensitivity in Dutch Shetland pony mares
Authors: Schurink A. , Ducro B. J. , Bastiaansen J. W. M. , Frankena K. , van Arendonk J. A. M.
Published: May 2012

Insect bite hypersensitivity (IBH) is the most common allergic disease present in horses worldwide. It has been shown that IBH is under genetic control, but the knowledge of associated genes is limited. We conducted a genome‐wide association study to identify and quantify genomic regions contributing to IBH in the Dutch Shetland pony population. A total of 97 cases and 91 controls were selected and matched on withers height, coat colour and pedigree to minimise the population stratification. A blood sample was collected from participating Shetland pony mares, their IBH phenotype was scored and the owner filled in a questionnaire. A total of 40 021 single‐nucleotide polymorphisms (SNPs) were fitted in a univariable logistic model fitting an additive effect. Analysis revealed no effects of population stratification. Significant associations with IBH were detected for 24 SNPs on 12 chromosomes [−log10(P‐value) > 2.5]. Odds ratios of allele substitution effects of the unfavourable allele were between 1.94 and 5.95. The most significant SNP was found on chromosome 27, with an odds ratio of 2.31 and with an allele frequency of the unfavourable allele of 0.72 in cases and 0.53 in controls. Genome‐wide association studies on additional horse populations are desired to validate the identified associations, to identify the genes involved in IBH and to develop genomic tools to decrease IBH prevalence.
Is honesty the best policy? Testing signal reliability in fiddler crabs when receiver‐dependent costs are high
Authors: Bywater Candice L. , Wilson Robbie S.
Published: May 2012

1.Contests between conspecific males are an important method of establishing mating rights or territories, yet the potential costs of injuries are high. To reduce potential risks, males can use signals to convey information about their underlying strength to competitors, and although individuals could signal deceptively to gain an advantage, most signals seem to be reliable.

2.Theory suggests that signal reliability is maintained because individuals that signal unreliably may be punished (i.e. receiver‐imposed costs). Manipulative studies support this idea, showing that low‐quality individuals that are given high‐quality signals bear substantial costs.

3.Here, we explore the importance of receiver‐imposed costs in natural, un‐manipulated populations. Specifically, we show how the likelihood of being exposed (i.e. potential receiver density) and the potential severity of punishment (i.e. average receiver size) affect the predominance of unreliable signalling among populations.

4.Male fiddler crabs, Uca vomeris, use their enlarged claws as signals and weapons in combat, and the relationship between claw size (signal) and strength (quality) determines whether or not a male is a reliable signaller. We predicted that the prevalence of unreliable signalling among individual males would increase in populations where the receiver‐imposed costs of deception were low. That is, males should produce unreliable (large but weak) claws.

5.We show that individual crabs produce more reliable signals of strength in populations with a high biomass, where there are both higher densities and larger average body sizes of potential receivers. Our study provides evidence that receiver‐imposed costs can maintain signal reliability in natural un‐manipulated populations and supports contemporary models of aggressive signalling.
Oestrogen‐deficiency inducing haematopoiesis dysfunction via reduction in haematopoietic stem cells and haematopoietic growth factors in rats
Authors: Qiu Xi , Yuan Xiang‐Gui , Jin Xiao‐li , He Xin , Zhu Lei , Zhao Xiao‐Ying
Published: May 2012

Haematopoiesis is a self‐renewing and multi‐directional differentiation process of haematopoietic stem cells (HSCs), which is modulated very precisely by the haematopoietic microenvironment in bone marrow. Our previous study has demonstrated that oestrogen‐deficiency leads to haematopoiesis dysfunction which manifests as a decrease in haematopoietic tissues and an increase in adipose tissues in bone marrow. However, the mechanism involved in the oestrogen‐deficiency effects on haematopoiesis dysfunction is not completely understood. In this study, we established an oestrogen‐deficiency rat model by ovariectomy (OVX group). Haematopoiesis was evaluated at the 12th, 16th, 20th, 24th and 28th weeks after operation in the OVX group and its control (Sham group) by pathological examination; the number and function of HSCs were evaluated by flow cytometry analysis and colony‐forming assay respectively. Haematopoietic growth factors levels including granulocyte/macrophage‐colony‐stimulating factor (GM‐CSF), stem cell factor (SCF) and interleukin‐3 (IL‐3) were examined by ELISA kits at different time points. We found that in the OVX group, haematopoiesis dysfunction in bone marrow was observed (P < 0.05) from the 12th week when compared with the Sham group, and extramedullary haematopoiesis began to appear in the liver and spleen from the 16th week. The number of HSCs and colony‐forming units‐granulocyte/macrophage (CFUs‐GM) in bone marrow was reduced significantly (P < 0.05) from the 20th and 16th week respectively. Furthermore, GM‐CSF, SCF and IL‐3 in the OVX group decreased significantly (P < 0.05) since the 12th, 16th and 24th week respectively. Taken together, these results suggested that oestrogen is required for normal haematopoiesis. Oestrogen‐deficiency inducing haematopoiesis dysfunction may be via reduction in HSCs and haematopoietic growth factors at a late stage.
Effects of long‐term experimental diabetes on adrenal gland growth and phosphoribosyl pyrophosphate formation in growth hormone‐deficient dwarf rats
Authors: Kunjara Sirilaksana , Greenbaum A. Leslie , McLean Patricia , Grønbaek Henning , Flyvbjerg Allan
Published: May 2012

The availability of growth hormone (GH)‐deficient dwarf rats with otherwise normal pituitary function provides a powerful tool to examine the relative role of hyperglycaemia and the reordering of hormonal factors in the hypertrophy‐hyperfunction of the adrenal gland that is seen in experimental diabetes. Here, we examine the effects of long‐term (6 months) experimental diabetes on the growth of the adrenal glands; their content of phosphoribosyl pyrophosphate (PRPP); and the activity of the PRPP synthetase, G6P dehydrogenase and 6PG dehydrogenase enzymes in GH‐deficient dwarf rats compared to heterozygous controls. These parameters were selected in view of the known role of PRPP in both de novo and salvage pathways of purine and pyrimidine synthesis and in the formation of NAD, and in view of the role of the oxidative enzymes of the pentose phosphate pathway in both R5P formation and the generation of the NADPH that is required in reductive synthetic reactions. This study shows that GH deficiency prevents the increase in adrenal gland weight, PRPP synthetase, PRPP content and G6P dehydrogenase and 6PG dehydrogenase. This contrasts sharply with the heterozygous group that showed the expected increase in these parameters. The blood glucose levels of the groups of long‐term diabetic rats, both GH‐deficient and heterozygous, remained at an elevated level throughout the experiment. These results are fully in accord with earlier evidence from studies with somatostatin analogues which showed that the GH‐insulin‐like growth factor I (IGF‐I)‐axis plays a key role in the adrenal diabetic hypertrophy‐hyperfunction syndrome.
Next‐of‐kin’s conceptions of medical technology in palliative homecare
Authors: Munck Berit , Sandgren Anna , Fridlund Bengt , Mårtensson Jan
Published: May 2012

Aims and objectives.  Describe next‐of‐kin’s conceptions of medical technology in palliative homecare.

Background.  Next‐of‐kin to palliative patients are in an exposed position with increasing responsibility. The more involved they are in the care, the greater caregiver burden they describe. Medical technology has become increasingly common in palliative homecare, and previous research suggests that the devices transform the homes to a hospital ward, thus shifting responsibility from the personnel to the next‐of‐kin.

Design.  An explorative descriptive design with a phenomenographic approach was chosen to describe qualitatively different conceptions of the phenomenon medical technology.

Method.  Interviews with 15 next‐of‐kin to patients in palliative homecare were analysed in a seven‐step process where 10 conceptions emerged in five description categories.

Results.  Medical technology in palliative homecare required next‐of‐kin’s responsibility in monitoring or providing practical help. It also implied uncertainty among the next‐of‐kin because of worries about its safety or because of an improper handling. The technology trespassed on daily life because it restricted and affected the private sphere. Medical technology enabled comfort as it implied security and was a prerequisite for the patient to be cared for at home. It also required an adjustment to comprehend and manage the medical technology.

Conclusions.  Medical technology resulted in an increased caregiver burden and uncertainty among the next‐of‐kin. Although it meant restrictions and affected their social life, they had great confidence in its possibilities.

Relevance to clinical practice.  It is important to limit the amount of personnel and materials in the home to avoid trespassing on the family’s daily life. Medical personnel also have to be sensitive to what next‐of‐kin have the strength to do and not use them as informal caregivers.