bluuebunny/crossref_metadata_2025 huggingface dataset:
Reasons to Be Cheerful: Thinking Sustainably in a (Climate) Changing World
Authors: Hobson Kersty
Published: April 2008

Although some still claim them as purely technological and economic concerns, climate change and sustainability present profound challenges to all levels of practice, from international governance institutions to domestic day‐to‐day habits. This diagnosis has become increasingly emphasised in environmental governance debates, which raises questions about how we all might engage with and think about making changes to these often highly charged spheres of practice, to encourage environmental and socially sustainability. In this article, I draw on recent experiences of a sustainable living workshop in Adelaide, Australia, to discuss how insights from participants’ views on appropriate models of social change – particularly the perspective of one ‘street philosopher’– along with human geographical environmental governance research, and aspects of gestalt theory can together suggest a positive and creative research praxis: one that works to draw out subjects (and our own) stories and aspirations to ‘think sustainably’.
Effects of Milling on Functional Properties of Rice Flour
Authors: Kadan R.S. , Bryant R.J. , Miller J.A.
Published: April 2008

ABSTRACT:  A commercial long‐grain rice flour (CRF) and the flours made by using a pin mill and the Udy mill from the same batch of broken second‐head white long‐grain rice were evaluated for their particle size and functional properties. The purpose of this study was to compare the commercial rice flour milling method to the pin and Udy milling methods used in our laboratory and pilot plant. The results showed that pin milled flour had more uniform particle size than the other 2 milled flours. The chalky kernels found in broken white milled rice were pulverized more into fines in both Udy milled flour and CRF than in the pin milled flour. The excessive amount of fines in flours affected their functional properties, for example, WSI and their potential usage in the novel foods such as rice breads (RB). The RB made from CRF collapsed more than loaves made from pin milled Cypress long‐grain flours.
Effects of Inulin and Oligofructose on the Rheological Characteristics and Probiotic Culture Survival in Low‐Fat Probiotic Ice Cream
Authors: Akalın A.S. , Erişir D.
Published: April 2008

ABSTRACT:  The effects of supplementation of oligofructose or inulin on the rheological characteristics and survival of Lactobacillus acidophilus La‐5 and Bifidobacterium animalis Bb‐12 in low‐fat ice cream stored at –18 °C for 90 d were studied. Addition of oligofructose or inulin to ice cream mix significantly increased apparent viscosity and overrun and developed the melting properties in ice cream during storage (P < 0.05). However, the highest increase in firmness, the lowest change in melting properties, and the longest 1st dripping time were obtained in probiotic ice cream containing inulin (P < 0.05). Some textural properties have also improved especially by the end of storage. Freezing process caused a significant decrease in the viability of Lactobacillus acidophilus La‐5 and Bifidobacterium animalis Bb‐12 (P < 0.05). Oligofructose significantly improved the viability of L. acidophilus La‐5 and B. animalis Bb‐12 in ice cream mix (P < 0.05). Although the viable numbers for both bacteria decreased throughout the storage, the minimum level of 106 CFU/g was maintained for B. animalis Bb‐12 in only ice cream with oligofructose during storage.
Characterization of Free Flavor Compounds in Traminette Grape and Their Relationship to Vineyard Training System and Location
Authors: Ji T. , Dami I.E.
Published: April 2008

ABSTRACT: Free volatile flavor compounds in Traminette grape were characterized and compared to those in benchmark white cultivars by gas chromatography‐mass spectrometry with headspace solid phase microextraction. In addition, the effects of vineyard site location (hot compared with cool based on growing degree days) and various training systems on yield components, standard characteristics (Brix, pH, and TA), and flavor compounds in Traminette grape juice were also evaluated for 2 seasons. Twenty‐two free volatiles were identified in Traminette juice. The most abundant volatile compounds included hexanal,trans‐2‐hexenal, linalool, nerol, and geraniol. These compounds were quantified and compared with those in Chardonnay, Gewürztraminer, and Riesling juice. The hexanal concentration was the highest in Chardonnay, andtrans‐2‐hexenal concentration was the lowest in Riesling. Traminette contained the highest amount of monoterpenes, especially geraniol. Concentrations of free volatile compounds in Traminette varied between the hot site and the cool site. In fact, the concentrations of 6‐carbon aldehydes were higher in Traminette grown in the cool site than those grown in the hot site, whereas monoterpenes were higher in the hot site than in the cool site. Among the 5 training systems, vines on the vertical shoot‐positioned produced the highest amount of monoterpenes, specifically geraniol. Our study suggests that Traminette is a flavorful cultivar that contains free volatile flavor compounds similar to the parent Gewürztraminer, but at much higher concentrations. The accumulation of odor chemicals in Traminette was affected by vineyard location and training system. Finally, geraniol was the most characteristic odor in Traminette, and its presence can be used as a quality indicator for this cultivar.
Measurement‐Burst Designs for Social Health Research
Authors: Sliwinski Martin J.
Published: April 2008

Questions about variability and change in human behavior lie at the heart of much research in the behavioral sciences. This commentary examines the use of the measurement‐burst design (Nesselroade, 1991) as an approach to study within‐person processes that transpire over very different temporal intervals. Consisting of repeated bursts of intensive (i.e., daily or momentary) assessments, the burst design can augment the type of information obtained from conventional daily diary and prospective longitudinal designs. We describe how the measurement‐burst approach can improve detection of long‐term intraindividual change, and how it can be used to study intraindividual variability and change in fine‐grained temporal relationships between daily experiences (e.g., hassles) and psychological states (e.g., mood). Some of the difficulties of implementing and analyzing data from measurement‐burst designs are discussed.
Statistical Power Analysis in Psychological Research
Authors: Abraham W. Todd , Russell Daniel W.
Published: April 2008

Reviews of the psychological literature suggest that many studies lack sufficient statistical power to detect effects of interest. Increased attention to statistical power by journal editors, reviewers, and funding agencies has led to a need for researchers to consider power carefully when designing studies. Our goal is to present an overview of issues that influence statistical power in the context of traditional research designs and analytic methods. We then extend the discussion of statistical power to complex designs and analyses providing readers with sources useful for evaluating power in the design stage of conducting research. Finally, we advocate the use of simulation and Monte Carlo methods as a flexible general strategy for designing research studies with adequate statistical power.
An Introduction to Latent Class Growth Analysis and Growth Mixture Modeling
Authors: Jung Tony , Wickrama K. A. S.
Published: April 2008

In recent years, there has been a growing interest among researchers in the use of latent class and growth mixture modeling techniques for applications in the social and psychological sciences, in part due to advances in and availability of computer software designed for this purpose (e.g., Mplus and SAS Proc Traj). Latent growth modeling approaches, such as latent class growth analysis (LCGA) and growth mixture modeling (GMM), have been increasingly recognized for their usefulness for identifying homogeneous subpopulations within the larger heterogeneous population and for the identification of meaningful groups or classes of individuals. The purpose of this paper is to provide an overview of LCGA and GMM, compare the different techniques of latent growth modeling, discuss current debates and issues, and provide readers with a practical guide for conducting LCGA and GMM using the Mplus software.
The Social Science Study of American Race Relations in the Twentieth Century*
Authors: Pettigrew Thomas F.
Published: April 2008

Racial oppression and conflict have remained a major concern of the USA throughout its history. Not surprisingly, then, ‘race relations’– as it is euphemistically termed – has been a focus of American social science since its origins in the late nineteenth century. This focus, however, has been uneven over the past century – often dim and reflecting the racist norms of the times but on occasion intense and pointing the way for reform. This chapter will briefly outline this uneven history of reflection and reform throughout the twentieth century with special attention to how the emerging discipline of American social psychology fits into this larger social scientific scene.
Prefrontal Cortex, Emotion, and Approach/Withdrawal Motivation
Authors: Spielberg Jeffrey M. , Stewart Jennifer L. , Levin Rebecca L. , Miller Gregory A. , Heller Wendy
Published: April 2008

This article provides a selective review of the literature and current theories regarding the role of prefrontal cortex, along with some other critical brain regions, in emotion and motivation. Seemingly contradictory findings have often appeared in this literature. Research attempting to resolve these contradictions has been the basis of new areas of growth and has led to more sophisticated understandings of emotional and motivational processes as well as neural networks associated with these processes. Progress has, in part, depended on methodological advances that allow for increased resolution in brain imaging. A number of issues are currently in play, among them the role of prefrontal cortex in emotional or motivational processes. This debate fosters research that will likely lead to further refinement of conceptualizations of emotion, motivation, and the neural processes associated with them.
Social Identity Theory and Self‐categorization Theory: A Historical Review
Authors: Hornsey Matthew J.
Published: April 2008

The social identity approach (comprising social identity theory and self‐categorization theory) is a highly influential theory of group processes and intergroup relations, having redefined how we think about numerous group‐mediated phenomena. Since its emergence in the early 1970s, the social identity approach has been elaborated, re‐interpreted, and occasionally misinterpreted. The goal of this paper is to provide a critical, historical review of how thinking and research within the social identity approach has evolved. The core principles of the theories are reviewed and discussed, and their effect on the field assessed. Strengths and limitations of the approach are discussed, with an eye to future developments.
Feminist Criminology: Gain, Loss and Backlash
Authors: Moore Dawn
Published: April 2008

Surviving the inevitable process of innovation, critique and response that accompanies conceptual invention, feminist criminology is now a rich and diverse field of scholarship and political activism. This article follows the main threads of feminist criminological thought (empirical, standpoint and post‐modern), outlining the tensions and connections between each. I then consider the political ground gained and lost by feminist criminologists, paying careful attention to the ways in which feminist ideas have been co‐opted by governing authorities and also considering the current climate of backlash against feminist ideas in both criminal justice policy and the academy.
TheEthnosin thePolis: Political Ethnography as a Mode of Inquiry
Authors: Baiocchi Gianpaolo , Connor Brian T.
Published: April 2008

In the social sciences, there is renewed attention to political ethnography, a research method that is based on close‐up and real‐time observation of actors involved in political processes, at times even extending the definition of these processes to move beyond categories of state, civil society, and social movements. This article examines the emergence of political ethnography from a number of disciplinary locations, such as political science, the cultural turn in sociology, and anthropology, and shows the value of this new approach for understanding how politics work in everyday life.
Gender and the ‘New Paradigm’ of Health
Authors: Moore Sarah E. H.
Published: April 2008

This article provides a critical review of literature on the relationship between gender and the ‘new paradigm’ of health. An overview of the feminist critique of health is given, from the Women's Health Movement of the late 1960s and early feminist debates about medicalisation, to more recent discussions about structural inequalities between men and women, eating disorders, and AIDS. I then go on to explore the feminist response to the so‐called ‘new paradigm’ of health (an approach that emphasises health promotion, individual responsibility for health, and body‐monitoring). Arguments that health promotion initiatives target women and confirm their position as principal guardians of health within the family are considered, as well as literature on the breast cancer awareness campaign. I then explore the growing body of literature on masculinity and health, and its account of the relationship between gender and current ideas about healthiness. Finally, I offer up some suggestions for the direction a new feminist critique of health might take.
The Study of Youth Labor: The Shift Toward a Subject‐Centered Approach
Authors: Besen‐Cassino Yasemin
Published: April 2008

In recent years, part‐time work has emerged as an important area of study in understanding young people's lives. The existing literature on young people's work focuses predominantly on the effects of youth labor, particularly on academic progress, future employment, emotional development, and deviant behavior. While youth employment has been studied extensively from the perspectives of parents, educators, and policy‐makers, the central actors – young people themselves – have been relatively neglected and young people's motives behind work remain virtually unexplored. A bourgeoning literature advocates a subject‐centric approach and proposes an understanding of youth labor from the perspective of young people. In this paper, I aim to (i) survey the existing literature on youth employment in the USA and Europe, (ii) examine the differences that come from adopting a subject‐centered approach, and (iii) discuss the implications of this shift for the future of youth labor literature.
Sociology and the Art of Risk
Authors: Mythen Gabe
Published: April 2008

In contemporary society, risk has become an ever‐present issue that appears across a range of social domains, such as health, welfare, crime, national security and the environment. High‐profile risk incidents such as 9/11, the Asian tsunami and Hurricane Katrina in New Orleans have served to underscore the global significance of risk. Although risk has conventionally been approached in the natural sciences as an object to be technically mastered by mathematical probability, since the early 1980s social scientists have focussed on the subjective and social dimensions of risk. This article traces the contours of the ‘turn to risk’ within sociology, outlining the central tenets of the risk society, governmentality and sociocultural theories. Both the utility of and the limits to these theories are demonstrated through practical application. The article concludes by considering some of the problems and contradictions that arise out of the sociological turn to risk.
The Sociology of Death
Authors: Walter Tony
Published: April 2008

The understanding of death, dying and bereavement in relation to society is indebted to a number of disciplines – anthropology, history, psychology and sociology are surveyed. Theories and methods used by sociologists of death, dying and bereavement are briefly outlined, followed by a number of key debates and challenges: denial, taboo and sequestration; death and the media; how to integrate scholarship in collective memory and Holocaust studies; theorising contemporary rites of passage; the lack of comparative research; and the need to focus on the meaning and organisation of death for those who encounter it most directly; namely, the poor, displaced and elderly. A brief discussion of undergraduate and postgraduate teaching is followed by the conclusion that any promise of a general sociology conducted in the light of mortality has been eclipsed by yet another specialism, the sociology of death.
What determines whether a species of insect is described? Evidence from a study of tropical forest beetles
Authors: STORK NIGEL E. , GRIMBACHER PETER S. , STOREY ROSS , OBERPRIELER ROLF G. , REID CHRIS , SLIPINSKI S. ADAM
Published: April 2008

Abstract. 

The rainforest canopy has been called ‘the last biological frontier’, and if this is true, there should be more undescribed species in this stratum than the ground stratum.

Here, we test this and other hypotheses regarding traits of described and undescribed species by a sub‐sample of 156 species into 96 described and 60 undescribed species from a beetle assemblage of 1473 species collected from the canopy and ground in an Australian lowland rainforest.

We show that described species are significantly more likely to be in the canopy, are more likely to be larger and, if they are large, are more likely to have been described earlier.

Undescribed species are just as likely to be found near the ground as in the canopy and are more likely to be smaller.

After the first year of sampling, ‘new’ described and undescribed species not previously encountered continued to appear in each of three further years of trapping.

These data show that the canopy fauna is in fact relatively ‘well known’, and that the undescribed species to be found in both strata are likely to be smaller than described species and are less likely to be plant feeders.
Central Receiver System Solar Power Plant Using Molten Salt as Heat Transfer Fluid
Authors: Ortega J. Ignacio , Burgaleta J. Ignacio , Téllez Félix M.
Published: April 2008

Of all the technologies being developed for solar thermal power generation, central receiver systems (CRSs) are able to work at the highest temperatures and to achieve higher efficiencies in electricity production. The combination of this concept and the choice of molten salts as the heat transfer fluid, in both the receiver and heat storage, enables solar collection to be decoupled from electricity generation better than water∕steam systems, yielding high capacity factors with solar-only or low hybridization ratios. These advantages, along with the benefits of Spanish legislation on solar energy, moved SENER to promote the 17MWe Solar TRES plant. It will be the first commercial CRS plant with molten-salt storage and will help consolidate this technology for future higher-capacity plants. This paper describes the basic concept developed in this demonstration project, reviewing the experience accumulated in the previous Solar TWO project, and present design innovations, as a consequence of the development work performed by SENER and CIEMAT and of the technical conditions imposed by Spanish legislation on solar thermal power generation.
Performance of a Zero-Energy House
Authors: Rosta S. , Hurt R. , Boehm R. , Hale M. J.
Published: April 2008

A comparative study is reported to measure the actual performance of a zero-energy house (ZEH) of typical tract design. Ideally, a ZEH produces as much energy as it consumes in a year’s time. Two identically sized tract houses (149.6m2(1610ft2)) were constructed side by side in southwest Las Vegas, NV. One house is used as a base line (standard comparison) house and was built using conventional construction techniques. The other house, the ZEH, employs many energy saving features, solar power generation, and supplemental solar water heating. Both houses have been equipped with a network of sensors that measure virtually every aspect of energy usage in each home. Initially, both houses have been utilized as model homes in a tract housing development, so it was reasonable to believe that both experienced similar and consistent usage. Performance data are logged and are posted on the web. This paper describes the differences in construction details between the two houses. Results of monitoring are presented that contrast the performance of the two houses.
Optimal Orientation of a Liquid-Film Solar-Assisted Brine Concentrator
Authors: Kim Dae Hyun , Jenkins Bryan M.
Published: April 2008

Recently, an open, liquid-film concentrator has been both theoretically and experimentally evaluated for increasing evaporation and concentration rates above those for simple solar evaporator basins (Kim, D. H., Jenkins, B. M., Yore, M. W., and Kim, N. J., 2007, “Salt Recovery From Agriculture Drainage Water Using a Liquid Film Solar-Assisted Concentrator: Simulation and Model Validation,” Sol. Energy, 81(10), pp. 1314–1321). For azimuth and tilt angles of the inclined brine concentrator where the maximum solar gain and mean wind direction are not in concurrence, the optimum orientation to maximize evaporation over a fixed interval of time was determined by simulation. Simulation was performed using ten years of hourly weather data for two different locations where wind blows mostly from the south and the north throughout the year, respectively (Davis and Five Points, CA) with different orientations and slope angles. Maximum annual evaporation for Davis occurred with the concentrator facing southwest and sloped at the latitude angle. At Five Points, maximum evaporation occurred with the inclined surface facing north even with the less favorable angle for solar absorption, indicating the importance of the wind speed-dependent mass transfer coefficient on overall performance. Additional experiments are needed to validate the simulations.
Effect of Cover Inclination and Water Depth on Performance of a Solar Still for Indian Climatic Conditions
Authors: Tiwari Anil Kr. , Tiwari G. N.
Published: April 2008

Effects of condensing cover inclination and water depth on the convective heat transfer coefficient and yield have been studied for a passive solar still. Three solar stills with an effective basin area of 1m2 each have been studied for three inclinations of condensing cover, namely, 15deg, 30deg, and 45deg. An identical solar still, but with a fixed cover inclination of 30deg, has also been tested to evaluate the effects of varying water depth. Outdoor experiments have been conducted for New Delhi climatic conditions (28°37′N∕77°13′E). Hourly variations of temperatures (water, vapor, and cover) and of distillate yield have been recorded and analyzed to determine convective heat and mass transfer coefficients. The resulting calculative extrapolation of experimental data from clear-day operation shows that the combination of minimum water depth and 15deg inclination of the condensing cover leads to maximum annual distillate yield for the climatic conditions of New Delhi. However, a cover inclination of 45deg is almost equally effective on an annual basis, but with better winter performance.
A Scenario for a Secure Transportation System Based on Fuel From Biomass
Authors: West Ronald E. , Kreith Frank
Published: April 2008

This article presents a scenario to meet the future fuel needs of the U.S. ground transportation system that does not require hydrogen, can use existing technology, and eventually transition to ethanol from biomass. This scenario is based on a combination of the reduction of liquid fuel use by means of plug-in hybrid electric vehicles and generation of ethanol from biomass. The article also demonstrates the reduction in CO2 generation with this technology and the urgency of initiating a strategy for reducing gasoline consumption as soon as possible.
Radiative Transfer Within a Cylindrical Cavity With Diffusely/Specularly Reflecting Inner Walls Containing an Array of Tubular Absorbers
Authors: Melchior Tom , Steinfeld Aldo
Published: April 2008

Monte Carlo radiative transfer analysis is applied to a cylindrical cavity-receiver containing an array of high-temperature tubular absorbers directly exposed to concentrated solar power entering through a spectrally selective window. The cavity walls are assumed either diffusely or specularly reflective. The relative dimensions, the number of tubes, and their position are optimized for maximum energy transfer efficiency or maximum absorber temperature. A single-tube absorber operating at 2000K performs best when located at 60% relative distance to the cavity’s aperture. Higher absorber temperatures are attained for a specularly reflective cavity that serves as internal infrared mirror but at the expense of lower energy transfer efficiencies. In contrast, diffuse reflecting cavity walls promote a more uniform temperature distribution around the tubular absorber. Decreasing the window-to-cavity areas ratio further results in an increase of the absorber temperature, which peaks for an optimum absorber-to-cavity radii ratio. This optimum ratio shifts to lower values for multiple-tube absorbers. However, the average absorber temperature is not significantly affected by using multiple-tube absorbers of constant total cross sectional area.
Designed PCL Nanofibers Fabricated Using a Modified Electrohydrodynamic Process for Tissue Engineering
Authors: Kim GeunHyung , Kim WanDoo
Published: April 2008

An ideal scaffold should have good mechanical properties and provide a biologically functional implant site. Considering their large surface area, high porosity, and good interconnectivity of pores, electrospun micro-∕nanofibers have good potential as biomimic scaffolds. In this study, various poly(ε-carprolactone) webs consisting of uniaxially oriented micro-∕nanofibers were produced using an electrohydrodynamic process (electrospinning) with a conical electrode and two-axis collector. The oriented fibrous web showed mechanical orthotropic properties, which might be important for designing engineering scaffolds that mimic natural tissues, such as a blood vessel or ligament, which have orthotropic mechanical properties. In addition, the fabricated mats, which were electrospun using computer-assisted design, had good hydrophilic and good cellular behavior compared to a random fiber mat.
Biomedical Manufacturing: A New Frontier of Manufacturing Research
Authors: Shih Albert J.
Published: April 2008

A new frontier of manufacturing research, biomedical manufacturing, is presented. Advanced manufacturing technologies, such as manufacturing processes, systems, and quality control, can be readily applied to improve the safety, quality, cost, efficiency, and speed of healthcare service and biomedical research. The analogy of the hospital as a factory is explored to broadly and inclusively define biomedical manufacturing. Characteristics and engineering needs of biomedical manufacturing are discussed. Examples of the grinding and cutting of plaque in interventional cardiology and laparoscopic surgery on minimizing the nerve tissue thermal damage in surgery are presented to demonstrate the broad spectrum of biomedical manufacturing. On education, the scope and pedagogy for teaching a new senior undergraduate∕first-year-graduate level course in Biomedical Design and Manufacturing are discussed.
Solid Freeform Fabrication of Polycaprolactone∕Hydroxyapatite Tissue Scaffolds
Authors: Shor L. , Güçeri S. , Gandhi M. , Wen X. , Sun W.
Published: April 2008

Bone tissue engineering is an emerging field providing viable substitutes for bone regeneration. Freeform fabrication provides an effective process tool to manufacture scaffolds with complex shapes and designed properties. We developed a novel precision extruding deposition (PED) technique to fabricate composite polycaprolactone∕hydroxyapatite (PCL∕HA) scaffolds. 25% concentration by weight of HA was used to reinforce 3D scaffolds. Two groups of scaffolds having 60% and 70% porosities and with pore sizes of 450μm and 750μm respectively, were evaluated for their morphology and compressive properties using scanning electron microscopy and the mechanical testing. In vitro cell-scaffold interaction study was carried out using primary fetal bovine osteoblasts. The cell proliferation and differentiation were evaluated by Alamar Blue assay and alkaline phosphatase activity. Our results suggested that compressive modulus of PCL∕HA scaffold was 84MPa for 60% porous scaffolds and was 76MPa for 70% porous scaffolds. The osteoblasts were able to migrate and proliferate for the cultured time over the scaffolds. Our study demonstrated the viability of the PED process to fabricate PCL scaffolds having necessary mechanical property, structural integrity, controlled pore size, and pore interconnectivity desired for bone tissue engineering.
The Use of Stereolithography in Alveolar Reconstruction With Mandibular Block Bone Grafts
Authors: Campanelli S. L. , De Filippis L. A. C. , Ludovico A. D. , Falco A. , Tetè S.
Published: April 2008

Recently, stereolithography (SL), one of the most diffused techniques in the rapid prototyping area, has been used to realize surgical guides for the corrected positioning of dental grafts. This paper presents a methodology for the design and fabrication of stereolithographic surgical guides useful in alveolar reconstruction with mandibular block bone grafts. The integration between medical imaging techniques and SL was achieved. The surgical guides built with a SL machine were used as tools for surgical operations. This methodology allowed obtaining the maximum respect of the contiguous anatomical structures, the extraction of a limited amount of bone, a remarkable reduction of the operation time, and no alteration of teeth and inferior lip sensibility. The extraction and the positioning of onlay grafts within the chin resulted to be more precise and predictable using stereolithographic surgical guides.
Endogenous siRNAs Derived from Transposons and mRNAs in
Drosophila
Somatic Cells
Authors: Ghildiyal Megha , Seitz Hervé , Horwich Michael D. , Li Chengjian , Du Tingting , Lee Soohyun , Xu Jia , Kittler Ellen L.W. , Zapp Maria L. , Weng Zhiping , Zamore Phillip D.
Published: April 2008

Small interfering RNAs (siRNAs) direct RNA interference (RNAi) in eukaryotes. In flies, somatic cells produce siRNAs from exogenous double-stranded RNA (dsRNA) as a defense against viral infection. We identified endogenous siRNAs (endo-siRNAs), 21 nucleotides in length, that correspond to transposons and heterochromatic sequences in the somatic cells of
Drosophila melanogaster
. We also detected endo-siRNAs complementary to messenger RNAs (mRNAs); these siRNAs disproportionately mapped to the complementary regions of overlapping mRNAs predicted to form double-stranded RNA in vivo. Normal accumulation of somatic endo-siRNAs requires the siRNA-generating ribonuclease Dicer-2 and the RNAi effector protein Argonaute2 (Ago2). We propose that endo-siRNAs generated by the fly RNAi pathway silence selfish genetic elements in the soma, much as Piwi-interacting RNAs do in the germ line.
Role of physiology and environmental factors on food intake control in boys
Authors: Bellissimo Nick
Published: April 2008

To examine the hypothesis that physiologic regulation of short-term food intake (FI) in boys is affected by the interaction between physiological and environmental factors, four studies were conducted. The primary objectives were as follows: (i) to compare the effect of glucose and whey-protein (50 g) preloads on satiety and FI as affected by time to the next meal and body composition in normal weight (NW) and obese (OB) boys; (ii) to examine the role of short-duration physical activity on subjective appetite and to identify the role of and associations between fitness and FI at a pizza lunch 30 min after glucose and whey-protein drinks in NW boys; (iii) to determine the effect of television viewing (TVV) on FI of boys at a meal and its effect on caloric compensation at the test meal after a premeal glucose drink; and (iv) to determine the reproducibility of short-term FI and subjective appetite after a glucose preload, ventilation threshold (VT), and body composition assessed by bioelectrical impedance analysis (BIA). Obese boys responded less than NW boys to whey protein, with time (30 vs. 60 min) to the next meal the response decreasing to glucose but increasing to protein. Subjective appetite was increased by short-duration physical activity and FI following glucose and whey-protein preloads was positively associated with VT in boys. TVV while eating a meal contributed to increased energy intake by delaying normal mealtime satiation and reducing satiety signals from previously consumed foods. Short-term FI after a glucose preload, subjective appetite after glucose and physical activity, VT, and body composition assessed by BIA were reproducible in boys. In conclusion, physiologic regulation of short-term FI in boys was affected by the interaction between physiological and environmental factors. Macronutrient source, body weight and composition, time to the next meal, short-duration physical activity and fitness, and TVV at mealtime impacted on FI regulation in boys.
Pediatric exercise physiology symposium: a tribute to Oded Bar-Or
Authors: Klentrou Panagiota Nota
Published: April 2008

Dr. Oded Bar-Or was a pioneer in the study of children’s physical activity, exercise, and health. His diverse research interests led to numerous scientific explorations on thermoregulation, aerobic and anaerobic capacity, physical activity, economy of movement, obesity, neuromuscular diseases, asthma, cystic fibrosis (CF), and many more. To commemorate the extraordinary contributions that Dr. Bar-Or made to the study of exercise and youth, a symposium on pediatric exercise physiology was held at the CSEP’s 2006 Annual Meeting in Halifax. The papers in the following pages include the four papers presented by international colleagues in his memory.
Anaerobic performance when rehydrating with water or commercially available sports drinks during prolonged exercise in the heat
Authors: Coso Juan Del , Estevez Emma , Baquero Raúl Antonio , Mora-Rodriguez Ricardo
Published: April 2008

The effects that rehydrating drinks ingested during exercise may have on anaerobic exercise performance are unclear. This study aimed to determine which of four commercial rehydrating drinks better maintains leg power and force during prolonged cycling in the heat. Seven endurance-trained and heat-acclimatized cyclists pedaled for 120 min at 63% maximum oxygen consumption in a hot, dry environment (36 °C; 29% humidity, 1.9 m·s–1 airflow). In five randomized trials, during exercise, subjects drank 2.4 ± 0.1 L of (i) mineral water (WAT; San Benedetto®), (ii) 6% carbohydrate–electrolyte solution (Gatorade® lemon), (iii) 8% carbohydrate–electrolyte solution (Powerade® Citrus Charge), (iv) 8% carbohydrate–electrolyte solution with lower sodium concentration than other sports drinks (Aquarius® orange), or (v) did not ingest any fluid (DEH). Fluid balance, rectal temperature (Trec), maximal cycling power (Pmax), and leg maximal voluntary isometric contraction (MVC) were measured. During DEH, subjects lost 3.7 ± 0.2% of initial body mass, whereas subjects lost only 0.8% ± 0.1% in the other trials (p < 0.05). Final Trec was higher in DEH than in the rest of the trials (39.4 ± 0.1 °C vs. 38.7 ± 0.1 °C; p < 0.05). Pmax was similar among all trials. Gatorade® and Powerade® preserved MVC better than DEH (–3.1% ± 2% and –3.8% ± 2% vs. –11% ± 2%, p < 0.05), respectively, whereas WAT and Aquarius® did not (–6% ± 2%). Compared with DEH, rehydration with commercially available sports drinks during prolonged exercise in the heat preserves leg force, whereas rehydrating with water does not. However, low sodium concentration in a sports drink seems to preclude its ergogenic effects on force.
Adding carbohydrate to a high-fat meal blunts postprandial lipemia in women and reduces meal-derived fatty acids in systemic circulation
Authors: Knuth Nicolas D. , Remias David B. , Horowitz Jeffrey F.
Published: April 2008

The lipemic response to a meal is an important independent risk factor for the development of cardiovascular disease. The purpose of this study was to determine the effect of adding carbohydrate (CHO) to a fat meal on the bioavailability of ingested fat in different blood lipid fractions in men and women. On two separate occasions, 18 healthy adults (9 women, 9 men) ate either a high-fat meal (0.7 grams fat per kilogram) (FAT), or the same meal with added CHO (1 gram CHO per kilogram) (FAT+CHO) in the morning after a 12 h fast. Both meals were supplemented with [13C]-palmitate (25 mg·kg–1). Plasma concentrations of triglyceride (TG), fatty acids, insulin, and glucose were measured in blood samples taken hourly from 0 to 8 h after the meal. In addition, we measured TG concentrations in chylomicron (CHYLO-TG) and in very-low-density lipoprotein (VLDL-TG) fractions. The addition of CHO to the fat meal increased plasma glucose and insulin concentrations identically in men and women. In contrast, adding CHO to the fat meal reduced the plasma TG concentration in the 5 h after the meal in women (average 5 h [TG]: 1.27 ± 0.11 and 1.01 ± 0.09 mmol·L–1; p <0.05), but not in men (1.25 ± 0.23 and 1.24 ± 0.20 mmol·L–1). Despite differences in the lipemic response to the meals between men and women, we found that adding carbohydrate to a fat meal decreased the bioavailability of meal-derived [13C]-palmitate in the systemic fatty acid pool, and decreased the incorporation of [13C]-palmitate into VLDL-TG in both men and women. In summary, adding CHO to a fat meal markedly blunted the plasma TG response in women, but not in men, which may augment the atherogenic potential after each meal in men.
Correlation between the rate of weight loss and changes in body composition in obese postmenopausal women after 5 weeks: a pilot study
Authors: Arguin Hélène , Bouchard Danielle R. , Labonté Mélissa , Carpentier André , Ardilouze Jean-Luc , Dionne Isabelle J. , Brochu Martin
Published: April 2008

Approximately 25% of weight lost during restrictive diets (without exercise) is lean body mass (LBM). No study has yet investigated the impact of the rate of weight loss (RWL) on LBM and fat mass (FM). The purpose of this study was to investigate the relationships between the RWL and body composition in older obese women. Twenty obese postmenopausal women aged between 51 and 74 years enrolled in a 5 week dietary weight loss intervention. Subjects were characterized according to their RWL (low RWL < 0.74 kg·week–1 (n = 9) vs. high RWL ≥ 0.74 kg·week–1 (n = 11)). Total and trunk FM and LBM (by dual-energy X-ray absorptiometry) were measured before and after weight loss. A significant correlation was observed between the RWL (kg·week–1) and changes in LBM (kg·week–1) (r = 0.75; p = 0.0002). However, no association was observed with changes in FM (kg·week–1) (r = 0.40; p = 0.08). Both groups showed a similar decrease in FM (low RWL, –2.7 ± 0.9 kg,; high RWL, –3.2 ± 0.8 kg; p = 0.38), whereas losses in LBM were significantly higher in the high RWL than in the low RWL group (–1.6 ± 1.2 kg vs. –0.4 ± 1.1 kg; p = 0.05). An RWL > 0.74 kg·week–1 was associated with a greater loss of LBM, but had no extra benefits on FM after a 5 week weight loss program. Current guidelines, which recommend RWL up to 0.91 kg·week–1, might not be optimal to prevent decreases in LBM in postmenopausal women when no exercise is added.
Teaching old enzymes new tricks: engineering and evolution of glycosidases and glycosyl transferases for improved glycoside synthesisThis paper is one of a selection of papers published in this Special Issue, entitled CSBMCB — Systems and Chemical Biology, and has undergone the Journal's usual peer review process.
Authors: Shaikh Fathima Aidha , Withers Stephen G.
Published: April 2008

The therapeutic potential of glycosides has made them an attractive target for drug development. The biological extraction and chemical synthesis of these molecules is often challenging and low yielding, thus alternative methods for the synthesis of polysaccharides are being pursued. A new class of enzymes, glycosynthases, which are nucleophile mutants of glycosidases, can perform the transglycosylation reaction without hydrolyzing the product, and thus provide a valuable resource for polysaccharide and glycan synthesis. Directed evolution of glycosynthases has expanded the repertoire of glycosidic linkages formed and the donors and acceptors (both sugar and nonsugar) that can be used by the glycosynthase. The application of new screening methods, such as FACS, to the directed evolution of glycosynthases will aid in the development of enzymes that are able to efficiently synthesize new, and therapeutically relevant glycosidic linkages.
Chemical biology of tetracycline antibioticsThis paper is one of a selection of papers published in this Special Issue, entitled CSBMCB — Systems and Chemical Biology, and has undergone the Journal's usual peer review process.
Authors: Zakeri Bijan , Wright Gerard D.
Published: April 2008

For more than half a century, tetracycline antibiotics have been used to treat infectious disease. However, what once used to be a commonly prescribed family of antibiotics has now decreased in effectiveness due to wide-spread bacterial resistance. The chemical scaffold of the tetracyclines is a versatile and modifiable structure that is able to interact with many cellular targets. The recent availability of detailed molecular interactions between tetracycline and its cellular targets, along with an understanding of the tetracycline biosynthetic pathway, has provided us with a unique opportunity to usher in a new era of rational drug design. Herein we discuss recent findings that have clarified the mode of action and the biosynthetic pathway of tetracyclines and that have shed light on the chemical biology of tetracycline antibiotics.
Small and lethal: searching for new antibacterial compounds with novel modes of actionThis paper is one of a selection of papers published in this Special Issue, entitled CSBMCB — Systems and Chemical Biology, and has undergone the Journal's usual peer review process.
Authors: Pathania Ranjana , Brown Eric D.
Published: April 2008

The discovery of drugs used to combat infectious diseases is in the process of constant change to address the ever-worsening problem of antibiotic resistance in pathogens and a lack of recent success in discovering new antibacterial drugs. In the past 2 decades, research in both academia and industry has made use of molecular biology, genetics, and comparative genomics, which has led to the development of key technologies for the discovery of novel antibacterial agents. Genome-scale efforts have led to the identification of numerous molecular targets. Chemical diversity from synthetic combinatorial libraries and natural products is being used to screen for new molecules. A wide variety of approaches are being used in the search for novel antibiotics, and these can be categorized as being either biochemically focused or cell based. The over-riding goal of all methods in use today is to discover new chemical matter with novel mechanisms of action against drug-resistant pathogens.
Prediction of friction capacity of driven piles in clay using the support vector machine
Authors: Samui Pijush
Published: April 2008

The support vector machine (SVM) is an emerging machine learning technique where prediction error and model complexity are simultaneously minimized. This paper examines the potential of SVM to predict the friction capacity of driven piles in clay. This SVM is firmly based on the statistical learning theory and uses the regression technique by introducing accuracy (ε) insensitive loss function. The results are compared with those from a widely used artificial neural network (ANN) model. Overall, the SVM showed good performance and is proven to be better than ANN model. A sensitivity analysis has been also performed to investigate the importance of the input parameters. The study shows that SVM has the potential to be a useful and practical tool for prediction of friction capacity of driven piles in clay.
Wetting-induced volume changes in compacted silty clays and high-plasticity clays
Authors: Ferber Valéry , Auriol Jean-Claude , Cui Yu-Jun , Magnan Jean-Pierre
Published: April 2008

Wetting-induced deformations of compacted fine-grained soils are of particular interest in earthworks engineering, where embankment design needs to take into account potential future water-content variations. The influence of compaction rate on swelling potential and, more generally, wetting-induced deformations are analyzed in this paper on the basis of an original physical microstructural model. The interpretation of macroscopic experimental results obtained on a high-plasticity clay and a silty clay shows that the model enables quantitative description of intra- and inter-aggregate pore volume changes due to wetting. Using this approach, a fundamental difference was observed between the high-plasticity clay and the silty clay in wetting tests under vertical stress: tests performed on the high-plasticity clay can be analyzed using a microstructural model, whereas this model is not relevant for the analysis of silty clay behaviour, which is better interpreted in the framework of a conventional elastoplastic model. The interpretations were compared to microstructure observations, which support the main tendencies deduced from the model.
A novel filtration system for polyethylene glycol solutions used in the osmotic method of controlling suction
Authors: Delage Pierre , Cui Yu Jun
Published: April 2008

One of the problems encountered when using the osmotic technique of controlling suction is related to the possible crossing of polyethylene glycol (PEG) molecules through the semipermeable membrane. Of the various hypotheses proposed, the paper considers the hypothesis that the PEG solutions are not pure enough and have molecules that are small enough to cross the semipermeable membrane. The paper presents a novel PEG purification system in which two solutions at different concentrations are put in contact through a semipermeable membrane along a large exchange surface. A peculiarity of the system is that it creates two opposite fluxes through the membrane, where small PEG molecules go from the higher concentration solution towards the lower concentration solution, and water migrates in the opposite direction. It has been observed that a small quantity of small molecules of PEG 6000 crossed the molecular weight cutoff (MWCO) 3500 semipermeable membrane.