bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiscale Bayesian neural networks for soil water content estimation
Authors: Jana Raghavendra B. , Mohanty Binayak P. , Springer Everett P.
Published: August 2008

Artificial neural networks (ANN) have been used for some time now to estimate soil hydraulic parameters from other available or more easily measurable soil properties. However, most such uses of ANNs as pedotransfer functions (PTFs) have been at matching spatial scales (1:1) of inputs and outputs. This approach assumes that the outputs are only required at the same scale as the input data. Unfortunately, this is rarely true. Different hydrologic, hydroclimatic, and contaminant transport models require soil hydraulic parameter data at different spatial scales, depending upon their grid sizes. While conventional (deterministic) ANNs have been traditionally used in these studies, the use of Bayesian training of ANNs is a more recent development. In this paper, we develop a Bayesian framework to derive soil water retention function including its uncertainty at the point or local scale using PTFs trained with coarser‐scale Soil Survey Geographic (SSURGO)‐based soil data. The approach includes an ANN trained with Bayesian techniques as a PTF tool with training and validation data collected across spatial extents (scales) in two different regions in the United States. The two study areas include the Las Cruces Trench site in the Rio Grande basin of New Mexico, and the Southern Great Plains 1997 (SGP97) hydrology experimental region in Oklahoma. Each region‐specific Bayesian ANN is trained using soil texture and bulk density data from the SSURGO database (scale 1:24,000), and predictions of the soil water contents at different pressure heads with point scale data (1:1) inputs are made. The resulting outputs are corrected for bias using both linear and nonlinear correction techniques. The results show good agreement between the soil water content values measured at the point scale and those predicted by the Bayesian ANN‐based PTFs for both the study sites. Overall, Bayesian ANNs coupled with nonlinear bias correction are found to be very suitable tools for deriving soil hydraulic parameters at the local/fine scale from soil physical properties at coarser‐scale and across different spatial extents. This approach could potentially be used for soil hydraulic properties estimation and downscaling.
Effect of Endurance Exercise on Hepatic Lipid Content, Enzymes, and Adiposity in Men and Women
Authors: Devries Michaela C. , Samjoo Imtiaz A. , Hamadeh Mazen J. , Tarnopolsky Mark A.
Published: August 2008

Obesity and physical inactivity are independent risk factors for the development of nonalcoholic fatty liver disease (NAFLD). We determined the effect of endurance exercise training on hepatic lipid content and hepatic enzyme concentration in men and women. Waist circumference (WC), percent body fat (BF), computed tomography (CT) scans for liver attenuation (inverse relationship with hepatic lipid), bilirubin, alanine aminotransferase (ALT), and γ‐glutamyltransferase (GGT) plasma concentrations were measured before and after 12 weeks of endurance training in 41 lean and obese men and women. Exercise training did not change liver attenuation, body weight, percent BF, bilirubin, or ALT concentration, but did lower WC (P< 0.0001), and decreased GGT in men only (P= 0.01). Obese subjects had a lower liver attenuation than lean subjects (P= 0.04). Obese women had lower ALT than obese men (P= 0.03). GGT was lower in women before and after training. WC was positively correlated with GGT (r= 0.32,P= 0.003) and ALT (r = 0.320,P= 0.004) and negatively correlated with liver attenuation (r= −0.340,P= 0.03). Percent BF was negatively correlated with bilirubin (r= −0.374,P= 0.005). Liver attenuation was negatively correlated with ALT (r= −0.405,P= 0.003). Short‐term endurance training without weight loss does not alter hepatic lipid content. There was a strong relationship between GGT/ALT and body composition (percent BF) as well as between ALT and hepatic lipid content.
Overexpression of CART in the PVN Increases Food Intake and Weight Gain in Rats
Authors: Smith Kirsty L. , Gardiner James V. , Ward Helen L. , Kong Wing M. , Murphy Kevin G. , Martin Niamh M. , Ghatei Mohammad A. , Bloom Stephen R.
Published: August 2008

Objective: Cocaine‐ and amphetamine‐regulated transcript (CART) codes for a hypothalamic neuropeptide, CART (55–102), which inhibits food intake. Intracerebroventricular injection of CART (55–102) reduces appetite, but also results in motor abnormalities. More recently, studies have demonstrated that administration of CART directly into the paraventricular nucleus (PVN) increases food intake. To investigate the role of CART in the regulation of energy balance in the PVN, we used recombinant adeno‐associated virus (rAAV) to overexpress CART in the PVN.

Methods and Procedures: Male Wistar rats were injected with either rAAV‐encoding CART (rAAV‐CART) or rAAV‐encoding enhanced green fluorescent protein (rAAV‐EGFP) as a control. Food intake and body weight were measured regularly. Animals were fed on normal‐chow diet for the first 93 days of the study. After this point, they were fed on high‐fat diet. Animals were killed 138 days postinjection and blood and tissues were collected for analysis.

Results: Overexpression of CART in the PVN resulted in increased cumulative food intake and body weight gain compared with rAAV‐EGFP controls when fed normal chow. These changes became significant at day 65 and 79, respectively and were accentuated on a high‐fat diet. A 4% increase in food intake was observed in rAAV‐CART animals on a normal‐chow diet and a 6% increase when fed a high‐fat diet. At the end of the study, rAAV‐CART‐treated animals had higher circulating leptin concentrations in accord with their higher body weight.

Discussion: These data provide further evidence that hypothalamic CART plays an orexigenic role.
PGC-1α induces dynamic protein interactions on the ERRα gene multi-hormone response element nucleosome in kidney cells
Authors: Wang Liangli , Li Yin , Hu Peng , Teng Christina T.
Published: August 2008

ERR (oestrogen-related receptor)-α modulates the oestrogen signalling pathway and regulates genes participating in the physiological energy balance programme. Oestrogen and PGC-1α (peroxisome proliferator-activated receptor-γ coactivator-1α), the master regulator of the energy homoeostasis programme, both regulate the expression of ERRα through the MHRE (multi-hormone response element) of the ERRα gene. Although the molecular mechanism of oestrogen action on ERRα regulation is well characterized, the mechanism of PGC-1α induction is unclear. In this study, we examine chromatin structural changes and protein interactions at the MHRE nucleosome in response to PGC-1α expression in HK2 human kidney cells. We mapped the nucleosome positions of the ERRα gene promoter and examined the changes of histone acetylation in response to PGC-1α expression. The interactions of DNA-binding proteins, ERRα and ERRγ, co-activators {CBP [CREB (cAMP-response-element-binding protein)-binding protein], p300, PCAF (p300/CBP-associated factor)}, co-repressor [RIP140 (receptor-interacting protein of 140 kDa)] and RNA polymerase II at the MHRE nucleosome region were investigated over time before and after PGC-1α expression in the HK2 cells. We found a dynamic cyclic interaction of these proteins shortly after PGC-1α expression and a slower cycling interaction, with fewer proteins involved, 20 h later. By using the siRNA (small interfering RNA) knockdown approach, we discovered that ERRγ was involved in the initial phase, but not in the later phase, of PGC-1α-induced ERRα expression.
An RPE cell line as a useful in vitro model for studying retinoic acid receptor β: expression and affinity
Authors: Pavan Barbara , Dalpiaz Alessandro , Biondi Carla , Nieddu Marzia , De Luca Antonella , Prasad Puttur D. , Paganetto Guglielmo , Favaloro Bartolo
Published: August 2008

Retinoids mediate their biological effect by interacting with specific nuclear receptors. Of the several known RAR (retinoic acid receptor) subtypes, RAR-β is of particular interest, since its expression is silenced in many cancers and it is believed to be a tumour suppressor. Specific ligands of RAR-β can potentially be used in anti-cancer therapy. In the present study, we have investigated the feasibility of using HRPE cells (human retinal pigment epithelial cells) as an experimental model for characterizing RAR-β–ligand interaction. RT–PCR (reverse transcription–PCR) and Western blot analyses show that HRPE cells specifically express only RAR-β and none of the other receptor subtypes. In addition, we show that the expression of RAR-β increases with increasing passage number of the cells. Interestingly, the increase in RAR-β expression is not associated with telomere shortening, a typical biomarker of cellular senescence. In the present study, we also describe a protocol for characterizing RAR-β–ligand interactions using nuclear extract from late passage HRPE cells as a source of endogenous RAR-β. Using [3H]CD367 as the ligand, RAR-β in HRPE cells showed an affinity of 9.6±0.6 nM and a Bmax of 780±14 fmol/mg of protein. We have confirmed the feasibility of using this assay to detect the interaction of ligands with RAR-β by investigating the ability of certain flavonoids to inhibit the binding of [3H]CD367 to nuclear extracts from HRPE cells. The inhibition constant of the flavonoids for RAR-β was between approx. 1–30 μM, showing that the flavonoids interact with RAR-β with low affinity.
Aerobic interval training reduces cardiovascular risk factors more than a multitreatment approach in overweight adolescents
Authors: Tjønna Arnt E. , Stølen Tomas O. , Bye Anja , Volden Marte , Slørdahl Stig A. , Ødegård Rønnaug , Skogvoll Eirik , Wisløff Ulrik
Published: August 2008

The aim of the present study was to compare the effects of a multidisciplinary approach (MTG) and aerobic interval training (AIT) on cardiovascular risk factors in overweight adolescents. A total of 62 overweight and obese adolescents from Trøndelag County in Norway, referred to medical treatment at St Olav's Hospital, Trondheim, Norway, were invited to participate. Of these, 54 adolescents (age, 14.0±0.3 years) were randomized to either AIT (4×4 min intervals at 90% of maximal heart rate, each interval separated by 3 min at 70%, twice a week for 3 months) or to MTG (exercise, dietary and psychological advice, twice a month for 12 months). Follow-up testing occurred at 3 and 12 months. V̇O2max (maximal oxygen uptake) increased more after AIT compared with MTG, both at 3 months (11 compared with 0%; P<0.01) and 12 months (12 compared with −1%; P<0.01). AIT enhanced endothelial function compared with MTG at both 3 months (absolute change, 5.1 compared with 3.9%; P<0.01) and 12 months (absolute change, 6.3 compared with 1.0%; P<0.01). AIT was favourable compared with MTG in reducing BMI (body mass index), percentage of fat, MAP (mean arterial blood pressure) and increasing peak oxygen pulse. In addition, AIT induced a more favourable regulation of blood glucose and insulin compared with MTG. In conclusion, the novel findings of the present proof-of-concept study was that 3 months of twice weekly high-intensity exercise sessions reduced several known cardiovascular risk factors in obese adolescents more than that observed after a multitreatment strategy, which was initiated as hospital treatment. Follow-up at 12 months confirmed that AIT improved or maintained these risk factors to a better degree than MTG.
Employee Theft and the Coastal South Carolina Hospitality Industry: Incidence, Detection, and Response (Survey Results 2000, 2005)
Authors: Krippel Gregory L. , Henderson Linda R. , Keene Marvin A. , Levi Mariana , Converse Kelly
Published: August 2008

This longitudinal, empirical study of the Myrtle Beach, South Carolina, tourism industry examines employee theft and employers' strategies for detecting it. An extensive questionnaire collected information from tourism managers of restaurants, hotels, golf courses, and attractions. Over 50 per cent reported one or more incidents of employee theft; the dollar value of the thefts more than doubled from 2000 to 2005. Perpetrators were typically younger males who frequently targeted cash and inventory. They were caught through internal controls, special investigations, and whistleblowers. Tourism managers may need training in more sophisticated control strategies to combat the high-dollar theft threat.
How Tourism Destinations Evolve: The Notion of Tourism Local Innovation System
Authors: Prats Lluís , Guia Jaume , Molina Francesc-Xavier
Published: August 2008

The analysis of tourism destinations as territorial agglomerations, that is, industrial districts and clusters, has been given attention in this journal in recent years. In these analyses, tourist companies closely situated in a territory or space are claimed to benefit from available shared resources. These papers, however, do not focus on the key role that innovation and the relationships among actors have on the evolution of tourism destinations. In trying to close this gap, we use the notions of system of innovation and social network analysis, and apply them to the tourism industry, to introduce the Tourism Local Innovation System (TLIS) model. This model can be used to assess the innovation capacity of tourism destinations and, also, to design relational network structures that favour innovation. Finally, by using social network analysis methods to draw a destination's relational network map, we present the case of Costa Brava Centre (Mid-Costa-Brava) — the most visited destination in Catalonia, which at the same time is the most visited region in Spain — as an actual example of TLIS.
Low voltage organic light-emitting devices with triphenylphosphine oxide layer
Authors: Ha Mi-Young , Moon Dae-Gyu
Published: August 2008

We have developed low voltage driving organic light-emitting devices using triphenylphosphine oxide (Ph3PO) layers. The devices with a Ph3PO layer show high current density at a low voltage. For example, the current density of 20mA∕cm2 is achieved at a low voltage of 2.9V for the device consisted of 4,4′,4″-tris[N-(2-naphthyl)-N-phenyl-amino]-triphenylamine (2-TNATA), 4,4′-bis(2,2′-diphenylvinyl)-1,1′-biphenyl (DPVBi), and Ph3PO layers. Due to the good electron conduction property of Ph3PO, a luminance of 1017cd∕m2 is achieved at a low voltage of 3.0V in a device with a structure of ITO/2-TNATA/DPVBi:rubrene (1%,10nm)∕DPVBi (30nm)∕Ph3PO (60nm)∕LiF∕Al.
Efficient multilayer organic solar cells using the optical interference peak
Authors: Zhang Chunfu , Tong S. W. , Jiang Changyun , Kang E. T. , Chan D. S. H. , Zhu Chunxiang
Published: August 2008

A multilayer structure of copper phthalocyanine/poly(3-hexylthiophene-2,5-diyl): [6,6]-phenyl-C61-butyric acid methyl ester (CuPc/P3HT:PCBM) is used to extend the light absorption spectrum covering almost the entire visible spectrum. To maximize the light absorption, the total number of excitons created in the multilayer structure as a function of layer thickness of both CuPc and P3HT:PCBM is simulated by using the optical transfer matrix formalism. The solar cells with a device structure of ITO/PEDOT:PSS/CuPc/P3HT:PCBM/Al are fabricated with different layers thicknesses. The optimized solar cell with a high short circuit current density of 12.54mA∕cm2 and power conversion efficiency as high as 4.13% is achieved, owing to the utilization of the second optical interference peak in the multilayer structure for the enhanced light absorption.
A percolation model for random telegraph signals in metal-oxide-silicon field effect transistor drain current
Authors: Forbes L. , Miller D. A.
Published: August 2008

Random telegraph signals (RTS) typically do not follow a simple model with uniform charge distributions and electron trapping causing a change in the average threshold voltage. Most often RTS with amplitudes greater than one electron are observed. These signals do not have a normal or Gaussian amplitude distribution. A model is presented here for RTS where electron trapping modulates preferential current paths in the device active region.
Experimental estimation of friction energy within a bundle of single-walled carbon nanotubes
Authors: Yang TianYi , Zhou Zongrong , Fan Hui , Liao Kin
Published: August 2008

In this work, we have experimentally determined normalized friction energy between single-walled carbon nanotubes (SWCNTs) from tensile testing of SWCNT bundles using a simple scheme. The average normalized friction energy obtained is 0.22Nm−1. This result is further verified by molecular mechanics simulation of single nanotube or a bundle of nanotubes pulled out from a nanotube bundle. This numerical value offers an important design parameter for mechanical applications of carbon nanotubes.
Inducing ferromagnetism in ZnO through doping of nonmagnetic elements
Authors: Ma Y. W. , Yi J. B. , Ding J. , Van L. H. , Zhang H. T. , Ng C. M.
Published: August 2008

In this work, Zn, Al, Pt, Ag, and Au nonmagnetic metallic films were deposited on the surface of ZnO film, followed by high vacuum annealing at different temperatures. Results showed that (Zn,Al,Pt)∕ZnO films possessed room temperature ferromagnetism (RTF) after the vacuum annealing, while (Ag,Au)∕ZnO films did not. Our detailed structural investigations (transmission electron microscopy and x-ray photoelectron spectroscopy) revealed that this RTF was associated with the presence of metal clusters. The RTF disappeared in Al∕ZnO after a subsequent annealing in air, as metal clusters were oxidized. Pt∕ZnO remained ferromagnetic, as the metal cluster structure was stable subjected to the air annealing.
Domain structures of ferroelectric nanotubes controlled by surface charge compensation
Authors: Wang Jie , Kamlah Marc
Published: August 2008

Domain structures in ferroelectric nanotubes (FNTs) under different electrical boundary conditions are predicted through a phase field model. Simulation results show that domain structures are highly dependent on the compensation of polarization-induced surface charges. In order to reduce the depolarization energy, polarizations in FNTs form a vortex structure under an open-circuit boundary condition. When surface charges are compensated on the inner and outer surfaces, a multidomain structure is formed in FNTs as a result of competition between the long-range electrostatic and elastic interactions. However, a single-domain structure is energically favorable in FNTs if the upper and lower surfaces are short-circuited.
Tunable split-ring resonator for metamaterials using photocapacitance of semi-insulating GaAs
Authors: Boulais K. A. , Rule D. W. , Simmons S. , Santiago F. , Gehman V. , Long K. , Rayms-Keller A.
Published: August 2008

We report a method for tuning a split-ring resonator (SRR) using infrared light. The SRR unit cells are commonly used in arrays to form a metamaterial that exhibits an effective negative permeability and are often used in negative-refractive-index materials. The region of negative permeability is generally limited to a narrow bandwidth at a fixed frequency. In this work, we use photocapacitance as observed in undoped semi-insulating GaAs to modify the gap capacitance of a SRR. We demonstrate a continuously tunable frequency over the range of 0.1–1.5 GHz using a 975 nm laser diode with a power range of 0–189 mW.
The impacts of surface conditions on the vapor-liquid-solid growth of germanium nanowires on Si (100) substrate
Authors: Li C. B. , Usami K. , Muraki T. , Mizuta H. , Odal S.
Published: August 2008

The impacts of surface conditions on the growth of Ge nanowires on a Si (100) substrate are discussed in detail. On SiO2-terminated Si substrates, high-density Ge nanowires can be easily grown. However, on H-terminated Si substrates, growing Ge nanowires is more complex. The silicon migration and the formation of a native SiO2 overlayer on a catalyst surface retard the growth of Ge nanowires. After removing this overlayer in the HF solution, high-density and well-ordered Ge nanowires are grown. Ge nanowires cross vertically and form two sets of parallel nanowires. It is found that nanowires grew along ⟨110⟩ directions.
Highly stacked quantum-dot laser fabricated using a strain compensation technique
Authors: Akahane Kouichi , Yamamoto Naokatsu , Tsuchiya Masahiro
Published: August 2008

We used a strain compensation technique to fabricate highly stacked InAs quantum-dot (QD) structures on InP(311)B substrates. We stacked 60 layers of InAs QDs without degrading the crystal quality and produced a structure with a total QD density of 4.73×1012∕cm2. We then fabricated a broad area laser diode with a 30-layer stack of InAs QDs using conventional photolithography. The laser diode showed ground state lasing at 1.58μm with a threshold current of 162mA. The achievement of ground state lasing is due to the increase in QD density, which is a result of using the strain compensation technique.
On Distributing Quarterly National Growth among Regions
Authors: Pavía José Manuel , Cabrer Bernardí
Published: August 2008

In many countries a very important fraction of public expenditure is managed by regional authorities. However, in a world where economic life has quickened and become more turbulent, subnational institutions rarely have a timely regional macroeconomic picture at their disposal. The authors propose a guide to a method for estimating quarterly accounts of regions from the national quarterly and annual regional accounts, by the use of a temporal structure which eliminates possible spurious jumps. The robustness of the process and suggested practicalities are tested, and the proposal is also shown to produce better estimates than other uniregional methods often used in this framework.
Variable Decision Strategies, Rational Choice, and Situation-Related Travel Demand
Authors: Burnett Pat
Published: August 2008

Classical economic theory following Bentham and Mill assumes decision makers are completely informed, highly sensitive to differences between alternatives, and above all rational in being able to rank order the possible alternatives and choose among them on some measure of welfare (utility maximization). In recent years, this view has been successfully challenged by empirical studies of decision making, and many alternative decision rules have emerged (such as lexicographic, elimination by aspects, counting, conjunctive, heuristic additive difference, affective, take the best, and so on). Despite thirty years’ work on boundedly rational and cognitive approaches, the classical view is still widely accepted in urban travel demand modeling. This paper develops a newer conceptual framework for shopping travel situtations—namely, choice of shopping place on different kinds of tour, for different orders of goods, and for regional malls and neighborhood centers. Hypotheses concerning the use of different kinds of decision rule are generated for the different situations or contexts. A statistical design is provided for tests of these hypotheses using fieldwork, verbal protocol analysis, and low-level t-tests. Fifty-five MIT students are interviewed, and their protocols for the shopping situations recorded and analyzed. The findings are that decision rules are multiple and vary with context. Although the specific hypotheses of the paper are not strongly supported, there is overwhelming evidence of the widespread use of simple heuristics. Implications of the findings are drawn for future work in the travel demand field and the preference and choice field. In addition, the contribution of this paper to behavioral decision making is noted, through the extension of work on choice heuristics to a different field (travel demand) and the use of a fieldwork qualitative methodology.
Effects on Housing Prices of Urban Attraction and Labor-Market Accessibility
Authors: Osland Liv , Thorsen Inge
Published: August 2008

Through a hedonic approach the authors focus primarily on how house prices vary systematically with respect to some general spatial structure characteristics in a Norwegian region. The introduction of a gravity-based labor-market accessibility measure contributes significantly to explain variation in housing prices, and is used in a model formulation where the distance from the city center is accounted for. Based on these results we suggest a distinction between an urban-attraction effect and a labor-market accessibility effect. Quantitatively, the two distinct effects are found to contribute about equally to intraregional variation in housing prices.
Built-Up Encroachment and the Urban Field: A Comparison of Forty European Cities
Authors: Guérois Marianne , Pumain Denise
Published: August 2008

We define the urban field as the spatial organisation of urban densities according to decreasing gradients from centre to periphery. This urban field can be estimated from the encroachment of built-up areas. The CORINE Land Cover database enables the measurement of the gradient values for the spatial distribution of built-up areas in European cities. Instead of the exponential or power functions, which usually provide the best fit for the distributions of population densities, we find that two linear functions strongly differentiating a central and a peripheral gradient provide the best fit for built-up surfaces. The comparison between the 1990 and 2000 CORINE images demonstrates a convergence in the trend of urban spread between Northern and Southern European cities. However, it is still difficult from the data to decide which of the models of urban field is winning: will the steeper central gradient become diluted into the less dense periphery, or are the closer fringes of the central parts becoming integrated into the ordered pattern of the urban central agglomerations?
Collectivity and Differentiation: A Tale of Two Wine Territories
Authors: Patchell Jerry
Published: August 2008

To compete in global markets, winegrowers must balance the seeming contradictory needs for territorial reputation and differentiation. This paper examines how the Bordeaux wine territories of St-Emilion and Blaye construct self-governance to achieve that balance, and looks at the extent to which their efforts influence the regulatory and supply chain structures of the industry. I adapt common pool resource theory (CPR) as a framework for analysis because it posits a collectively generated asset that must be maintained through mutually agreed rules. I extend CPR by focusing on reputation rather than physical assets and by incorporating the need for differentiation. The co-evolution of collectivity and differentiation is traced to establish differing institutional structures. The mechanisms of cooperation—democracy, legitimacy, fairness, monitoring, enforcement, cost reduction—are analyzed and compared for effectiveness in integrating collectivity and differentiation and for achieving territorial ambitions.
Environmental Justice in the Israeli Context
Authors: Shmueli Deborah F
Published: August 2008

The ideal of environmental justice is a far reach for Israel, a country with severely limited land area, an overriding concern with security, and a significant minority population. Nevertheless, it is urgent that policy makers take steps in that direction, both for the health of the nation and for moral rightness. After a survey of theoretical approaches to environmental justice, the author offers an operative definition and theory appropriate to the Israeli situation. This approach, embodying all facets of the theory, is applied to a case study of the Arab town of Sachnin, and the policy implications that it indicates are explored. Specific steps that could help progress toward the ultimate goal of environmental justice are suggested.
Haptic Curvature Comparison of Convex and Concave Shapes
Authors: van der Horst Bernard J , Kappers Astrid M L
Published: August 2008

A sculpture and the mould in which it was formed are typical examples of objects with an identical, but opponent, surface shape: each convex (ie outward pointing) surface part of a sculpture has a concave counterpart in the mould. The question arises whether the object features of opponent shapes can be compared by touch. Therefore, we investigated whether human observers were able to discriminate the curvatures of convex and concave shapes, irrespective of whether the shape was convex or concave. Using a 2AFC procedure, subjects had to compare the curvature of a convex shape to the curvature of a concave shape. In addition, results were also obtained for congruent shapes, when the curvature of either only convex shapes or only concave shapes had to be compared. Psychometric curves were fitted to the data to obtain threshold and bias results. When subjects explored the stimuli with a single index finger, significantly higher thresholds were obtained for the opponent shapes than for the congruent shapes. However, when the stimuli were touched by two index fingers, one finger per surface, we found similar thresholds. Systematic biases were found when the curvature of opponent shapes was compared: the curvature of a more curved convex surface was judged equal to the curvature of a less curved concave surface. We conclude that human observers had the ability to compare the curvature of shapes with an opposite direction, but that their performance decreased when they sensed the opponent surfaces with the same finger. Moreover, they systematically underestimated the curvature of convex shapes compared to the curvature of concave shapes.
The Aesthetic Appeal of Auditory-Visual Synaesthetic Perceptions in People without Synaesthesia
Authors: Ward Jamie , Moore Samantha , Thompson-Lake Daisy , Salih Shireen , Beck Brianna
Published: August 2008

The term ‘visual music’ refers to works of art in which both hearing and vision are directly or indirectly stimulated. Our ability to create, perceive, and appreciate visual music is hypothesised to rely on the same multisensory processes that support auditory – visual (AV) integration in other contexts. Whilst these mechanisms have been extensively studied, there has been little research on how these processes affect aesthetic judgments (of liking or preference). Studies of synaesthesia in which sound evokes vision and studies of cross-modal biases in non-synaesthetes have revealed non-arbitrary mappings between visual and auditory properties (eg high-pitch sounds being smaller and brighter). In three experiments, we presented members of the general population with animated AV clips derived from synaesthetic experiences and contrasted them with a number of control conditions. The control conditions consisted of the same clips rotated or with the colour changed, random AV pairings, or animated clips generated by non-synaesthetes. Synaesthetic AV animations were generally preferred over the control conditions. The results suggest that non-arbitrary AV mappings, present in the experiences of synaesthetes, can be readily appreciated by others and may underpin our tendency to engage with certain forms of art.
Temporal Characteristics of Visibility in Chimpanzees (Pan Troglodytes) and Humans (Homo Sapiens) Assessed by a Visual-Masking Paradigm
Authors: Matsuno Toyomi , Tomonaga Masaki
Published: August 2008

We used the visual-masking paradigm to compare temporal characteristics of chimpanzee vision with those of humans. Two types of masking experiments were conducted. One type involved masking by noise, in which the visibility of the geometric pattern target was tested with a spatially overlapping noise as the mask stimulus. The other type involved paracontrast and metacontrast masking, in which the mask stimuli flanked but did not spatially overlap the target stimuli. Temporal characteristics regarding the visibility of target stimuli, displayed as functions of temporal asynchrony between target and mask stimuli, differed with the mask type in chimpanzees as in humans. Peak deterioration in visibility occurred at the point of minimum temporal asynchrony both in forward and backward masking by noise, but was not at 0 ms temporal asynchrony when the target and mask stimuli did not spatially overlap. These results suggest that chimpanzees and humans share the underlying mechanisms in two kinds of temporal inhibition caused by spatially overlapping and non-overlapping mask stimuli.
The Role of Holistic Processing in Judgments of Facial Attractiveness
Authors: Abbas Zara-Angela , Duchaine Bradley
Published: August 2008

Previous work has demonstrated that facial identity recognition, expression recognition, gender categorisation, and race categorisation rely on a holistic representation. Here we examine whether a holistic representation is also used for judgments of facial attractiveness. Like past studies, we used the composite paradigm to assess holistic processing (Young et al 1987, Perception16 747–759). Experiment 1 showed that top halves of upright faces are judged to be more attractive when aligned with an attractive bottom half than when aligned with an unattractive bottom half. To assess whether this effect resulted from holistic processing or more general effects, we examined the impact of the attractive and unattractive bottom halves when upright halves were misaligned and when aligned and misaligned halves were presented upside-down. The bottom halves had no effect in either condition. These results demonstrate that the perceptual processes underlying upright facial-attractiveness judgments represent the face holistically. Our findings with attractiveness judgments and previous demonstrations involving other aspects of face processing suggest that a common holistic representation is used for most types of face processing.
Observinga Object Motion Induces Increased Generalization and Sensitivity
Authors: Balas Benjamin , Sinha Pawan
Published: August 2008

Learning to recognize a new object requires binding together dissimilar images of that object into a common representation. Temporal proximity is a useful computational cue for learning invariant representations. We report experiments that demonstrate two distinct psychophysical effects of temporal association via observed object motion on object perception. First, we use an implicit priming criterion to demonstrate that observation of a dynamic object induces generalization over close temporal neighbors. Second, in contrast to predictions from previous work, we find that shape discrimination between images actually improves following the same training procedure. We suggest that these apparently conflicting sets of results, one demonstrating blurring and the other demonstrating sharpening of the perceived distinction between temporally proximate frames, are consistent with a highly redundant code for object appearance.
The Effect of Face Orientation on Holistic Processing
Authors: Mondloch Catherine J , Maurer Daphne
Published: August 2008

Holistic processing, a hallmark of face processing, can be measured by the composite face effect: adults have difficulty recognising the top half of a face when it is aligned with a new bottom half, unless holistic processing is disrupted by misaligning the two halves. Like the recognition of facial identity, holistic processing is impaired when faces are inverted. To obtain a more refined measure of the influence of orientation on holistic face processing, we administered the composite face task to adults at each of seven orientations. In both experiment 1 (in which orientations were randomly intermixed) and experiment 2 (in which orientations were blocked), the composite face effect decreased linearly with rotation. We conclude that holistic processing is tuned to upright faces, diminishes as faces deviate from upright, and becomes insignificant once faces reach a sideways orientation. We propose a hierarchical model of face perception in which linear decreases in holistic processing underlie qualitative shifts in other aspects of face perception.
An analysis of the sensitivity of sap flux to soil and plant variables assessed for an Australian woodland using a soil - plant - atmosphere model
Authors: Zeppel Melanie , Macinnis-Ng Catriona , Palmer Anthony , Taylor Daniel , Whitley Rhys , Fuentes Sigfredo , Yunusa Isa , Williams Mathew , Eamus Derek
Published: August 2008

Daily and seasonal patterns of tree water use were measured for the two dominant tree species, Angophora bakeri E.C.Hall (narrow-leaved apple) and Eucalyptus sclerophylla (Blakely) L.A.S. Johnson & Blaxell (scribbly gum), in a temperate, open, evergreen woodland using sap flow sensors, along with information about soil, leaf, tree and micro-climatological variables. The aims of this work were to: (a) validate a soil–plant–atmosphere (SPA) model for the specific site; (b) determine the total depth from which water uptake must occur to achieve the observed rates of tree sap flow; (c) examine whether the water content of the upper soil profile was a significant determinant of daily rates of sap flow; and (d) examine the sensitivity of sap flow to several biotic factors. It was found that: (a) the SPA model was able to accurately replicate the hourly, daily and seasonal patterns of sap flow; (b) water uptake must have occurred from depths of up to 3 m; (c) sap flow was independent of the water content of the top 80 cm of the soil profile; and (d) sap flow was very sensitive to the leaf area of the stand, whole tree hydraulic conductance and the critical water potential of the leaves, but insensitive to stem capacitance and increases in root biomass. These results are important to future studies of the regulation of vegetation water use, landscape-scale behaviour of vegetation, and to water resource managers, because they allow testing of large-scale management options without the need for large-scale manipulations of vegetation cover.
Photoprotective carotenoids and antioxidants are more affected by canopy position than by nitrogen supply in 21-year-old Pinus radiata
Authors: Posch Sabine , Warren Charles R. , Adams Mark A. , Guttenberger Helmut
Published: August 2008

Photoprotection, light harvesting and light utilisation were investigated as a function of variation in N supply and canopy position in 21-year-old Pinus radiata D. Don. Chlorophyll fluorescence, gas exchange and photoprotective compounds were measured on lower, middle and upper canopy needles in trees receiving N fertiliser and in control trees not receiving N fertiliser. Irrespective of canopy height, additional N increased the light-harvesting capacity through greater contents of chlorophyll, neoxanthin and lutein, but did not affect light-utilisation processes, such as effective quantum yield of PSII or rates of net CO2 assimilation. Additional N fertiliser did not affect the concentrations of the measured photoprotective carotenoids (violaxanthin, antheraxanthin, zeaxanthin, α-carotene and β-carotene) or antioxidants (ascorbic acid, glutathione and α-tocopherol); however, carotenoids and antioxidants were strongly affected by canopy height and increased in concentration with increasing canopy height. The present study found that pools of photoprotective carotenoids and antioxidants were not driven by imbalances in light-harvesting and light-utilisation processes, but rather by gradients in light.
Why is plant-growth response to elevated CO2 amplified when water is limiting, but reduced when nitrogen is limiting? A growth-optimisation hypothesis
Authors: McMurtrie Ross E. , Norby Richard J. , Medlyn Belinda E. , Dewar Roderick C. , Pepper David A. , Reich Peter B. , Barton Craig V. M.
Published: August 2008

Experimental evidence indicates that the stomatal conductance and nitrogen concentration ([N]) of foliage decline under CO2 enrichment, and that the percentage growth response to elevated CO2 is amplified under water limitation, but reduced under nitrogen limitation. We advance simple explanations for these responses based on an optimisation hypothesis applied to a simple model of the annual carbon–nitrogen–water economy of trees growing at a CO2-enrichment experiment at Oak Ridge, Tennessee, USA. The model is shown to have an optimum for leaf [N], stomatal conductance and leaf area index (LAI), where annual plant productivity is maximised. The optimisation is represented in terms of a trade-off between LAI and stomatal conductance, constrained by water supply, and between LAI and leaf [N], constrained by N supply. At elevated CO2 the optimum shifts to reduced stomatal conductance and leaf [N] and enhanced LAI. The model is applied to years with contrasting rainfall and N uptake. The predicted growth response to elevated CO2 is greatest in a dry, high-N year and is reduced in a wet, low-N year. The underlying physiological explanation for this contrast in the effects of water versus nitrogen limitation is that leaf photosynthesis is more sensitive to CO2 concentration ([CO2]) at lower stomatal conductance and is less sensitive to [CO2] at lower leaf [N].
Effects of different soil management practices on winter wheat yield and N losses on a dryland loess soil in China
Authors: Jin Ke , De Neve Stefaan , Moeskops Bram , Lu Junjie , Zhang Jie , Gabriels Donald , Cai Dianxiong , Jin Jiyun
Published: August 2008

One of the most important problems in the Loess Plateau of China affecting sustainable agriculture is inefficient nutrient use. Field experiments were conducted to study the effects of different soil management practices on the nitrogen (N) dynamics and winter wheat yield on a loess soil in Luoyang, Henan province, China. The results showed that subsoiling with mulch (SS) consistently increased the yield of winter wheat primarily by better water harvest compared with conventional tillage (CT). The influence on yield of no till with mulch (NT) depended on the amount of precipitation. TC (2 crops per year) lowered the winter wheat yield mainly due to the unfavourable soil moisture conditions after growing peanut in summer; however, the harvested peanut gained an extra profit for the local farmer. N uptake by grain and straw and N export was highest for SS. Changes in frequency and intensity of tillage practice altered soil total N content and its distribution along the slope. SS and NT increased the N content of the surface layer (0–0.20 m) compared with CT, but there was no significant effect in deeper soil layers. Considerable amounts of nitrate-N were left in the profile 0–1.60 cm just after harvest under all treatments. The cumulative nitrate-N content to a depth of 1.60 m on average was 282 kg/ha, of which 56 kg/ha was in the layer 1.20–1.60 m, which is an indication of considerable nitrate leaching. From data of 7 consecutive years between 1999 and 2006, it could be concluded that SS resulted in the highest yield and total N content in the surface layer, and is the most sustainable tillage option for the circumstances of the study area.
Prairie dog presence affects occurrence patterns of disease vectors on small mammals
Authors: Jory Brinkerhoff R. , Ray Chris , Thiagarajan Bala , Collinge Sharon K. , Cully Jack F. , Holmes Brian , Gage Kenneth L.
Published: August 2008

Wildlife disease is recognized as a burgeoning threat to imperiled species and aspects of host and vector community ecology have been shown to have significant effects on disease dynamics. The black‐tailed prairie dog is a species of conservation concern that is highly susceptible to plague, a flea‐transmitted disease. Prairie dogs (Cynomys) alter the grassland communities in which they exist and have been shown to affect populations of small rodents, which are purported disease reservoirs. To explore potential ecological effects of black‐tailed prairie dogs on plague dynamics, we quantified flea occurrence patterns on small mammals in the presence and absence of prairie dogs at 8 study areas across their geographic range. Small mammals sampled from prairie dog colonies showed significantly higher flea prevalence, flea abundance, and relative flea species richness than those sampled from off‐colony sites. Successful plague transmission likely is dependent on high prevalence and abundance of fleas that can serve as competent vectors. Prairie dogs may therefore facilitate the maintenance of plague by increasing flea occurrence on potential plague reservoir species. Our data demonstrate the previously unreported ecological influence of prairie dogs on vector species assemblages, which could influence disease dynamics.
Scale‐invariance of niche breadth in fleas parasitic on small mammals
Authors: Krasnov Boris R. , Mouillot David , Khokhlova Irina S. , Shenbrot Georgy I. , Poulin Robert
Published: August 2008

The resource specialization or niche breadth of a species is not fixed across populations, but instead varies over geographical space. A species may be a local specialist but a regional generalist, if it uses locally few resources that are substitutable across locations. In contrast, a species is a local generalist and a regional specialist if it uses locally many resources that cannot be substituted from 1 location to the next. Scale‐dependence can thus be a major factor in estimation of niche breadth. Here, we test for relationships between local and global estimates of host specificity (a measure of niche breadth for parasites) in fleas (Siphonaptera) parasitic on small mammals from 49 different regions within the Holarctic. Across all fleas, we found a strong, positive relationship between the number of host species that a flea uses in 1 locality and the number of different host species that can serve as the flea's principal host (i.e. the one supporting the most fleas in a region) among all regions. Also, we observed a strong positive relationship between the taxonomic distinctness of the host species used in 1 locality and that of all known principal hosts among all localities. These relationships held after correcting for potentially confounding phylogenetic influences. We discuss the implications of scale‐independent host specificity and its association with geographical range size and species‐specific patterns of host use.
Detecting spatial hot spots in landscape ecology
Authors: Nelson Trisalyn A. , Boots Barry
Published: August 2008

Hot spots are typically locations of abundant phenomena. In ecology, hot spots are often detected with a spatially global threshold, where a value for a given observation is compared with all values in a data set. When spatial relationships are important, spatially local definitions – those that compare the value for a given observation with locations in the vicinity, or the neighbourhood of the observation – provide a more explicit consideration of space. Here we outline spatial methods for hot spot detection: kernel estimation and local measures of spatial autocorrelation. To demonstrate these approaches, hot spots are detected in landscape level data on the magnitude of mountain pine beetle infestations. Using kernel estimators, we explore how selection of the neighbourhood size (τ) and hot spot threshold impact hot spot detection. We found that as τ increases, hot spots are larger and fewer; as the hot spot threshold increases, hot spots become larger and more plentiful and hot spots will reflect coarser scale spatial processes. The impact of spatial neighbourhood definitions on the delineation of hot spots identified with local measures of spatial autocorrelation was also investigated. In general, the larger the spatial neighbourhood used for analysis, the larger the area, or greater the number of areas, identified as hot spots.
Children's Physical Activity: The Contribution of Playing and Walking
Authors: Mackett Roger L. , Paskins James
Published: August 2008

This paper draws on research in which 200 children were fitted with motion sensors and asked to keep travel and activity diaries. The findings show that walking and playing away from home can contribute significantly to children's volume of physical activity, with consequent implications for their health. Not only do both playing and walking provide high levels of physical activity, they are linked to other behaviours which further augment the level of physical activity. Children who walk rather than use the car tend to be generally more active than other children, and children tend to be more active when they are out of their homes than when they are in them. The findings are placed in the context of other research about children's travel and physical activity, and conclusions drawn about the need to reverse current trends in children's patterns of travel and physical activity.