bluuebunny/crossref_metadata_2025 huggingface dataset:
Sucrose metabolism during fruit development in Coffea racemosa
Authors: Geromel C. , Ferreira L.P. , Bottcher A. , Pot D. , Pereira L.F.P. , Leroy T. , Vieira L.G.E. , Mazzafera P. , Marraccini P.
Published: November 2007

Sucrose is one of the compounds in the raw coffee bean that has been identified as an important precursor of coffee flavour and aroma. In order to increase our knowledge of sucrose metabolism in coffee species, sucrose and reducing sugar content were investigated in the fast fruit‐ripening coffee species Coffea racemosa. Fruits were harvested regularly from anthesis, until the point of complete fruit maturation and tissue development, followed by measurement of fruit tissue weight. Pericarp was the most abundant tissue, and always represented around 70–80% of fruit fresh weight. The perisperm present in young fruits was rapidly replaced by the endosperm at around 40 days after flowering (DAF). In the latter tissue, total and reducing sugars decreased during development. However, sucrose content was maintained at a relatively high level throughout fruit development, with a peak at 40 DAF that coincided with the highest level of sucrose synthase (SUS) activity detected in this tissue. For all endosperm developmental stages analysed, very low invertase activity was observed, suggesting a limited role for this enzyme in sucrose metabolism. Northern blot experiments using SUS1 and SUS2 cDNA sequences from Coffea arabica as probes were carried out to study the expression of SUS‐encoding genes. The SUS1 transcripts of C. racemosa overlapped with the peak of SUS activity in the endosperm, whereas SUS2 transcripts accumulated mainly during the latest stages of endosperm development. Altogether, these results suggest that the SUS1 isoform of SUS is essential for sucrose accumulation in the fruits of C. racemosa.
Hydraulic Tomography for Detecting Fracture Zone Connectivity
Authors: Hao Yonghong , Yeh Tian‐Chyi J. , Xiang Jianwei , Illman Walter A. , Ando Kenichi , Hsu Kuo‐Chin , Lee Cheng‐Haw
Published: November 2007

Fracture zones and their connectivity in geologic media are of great importance to ground water resources management as well as ground water contamination prevention and remediation. In this paper, we applied a recently developed hydraulic tomography (HT) technique and an analysis algorithm (sequential successive linear estimator) to synthetic fractured media. The application aims to explore the potential utility of the technique and the algorithm for characterizing fracture zone distribution and their connectivity. Results of this investigation showed that using HT with a limited number of wells, the fracture zone distribution and its connectivity (general pattern) can be mapped satisfactorily although estimated hydraulic property fields are smooth. As the number of wells and monitoring ports increases, the fracture zone distribution and connectivity become vivid and the estimated hydraulic properties approach true values. We hope that the success of this application may promote the development and application of the new generations of technology (i.e., hydraulic, tracer, pneumatic tomographic surveys) for mapping fractures and other features in geologic media.
Irreversible Phosphorus Sorption in Septic System Plumes?
Authors: Robertson W. D.
Published: November 2007

The mobility of phosphorus (P) in septic system plumes remains a topic of debate because of the considerable reactivity of this constituent. In this study, a septic system plume in Ontario was monitored over a 16‐year period with detail that clearly shows the advancing frontal portion of the P plume. This monitoring record provides insight into the extent of secondary P attenuation in the ground water zone beyond that available from previous studies. A P plume 16 m in length developed over the monitoring period with PO4‐P concentrations (3 to 6 mg/L) that approached the concentrations present under the tile bed. Simulations using an analytical model showed that when first‐order solute decay was considered to account for the possibility of secondary P attenuation in the ground water zone, field values could only be matched when decay was absent or occurred at an exceedingly slow rate (half‐life greater than 30 years). Thus, hypothesized secondary P attenuation mechanisms such as slow recystallization of sorbed P into insoluble metal phosphate minerals, diffusion into microsites, or kinetically slow direct precipitation of P minerals such as hydroxyapatite were inactive in the ground water zone at this site or occurred at rates that were too slow to be observed in the context of the current 16‐year study. Desorption tests on sediment samples from below the tile bed indicated a PO4 distribution coefficient (Kd) of 4.8, which implies a P retardation factor of 25, similar to the field apparent value of 37 determined from model calibrations. This example of inactive secondary P attenuation in the ground water zone shows that phosphorus in some ground water plumes can remain mobile and conservative for decades. This has important implications for septic systems located in lakeshore environments when long‐term usage scenarios are considered.
Permeability Hysterisis of Limestone During Isotropic Compression
Authors: Selvadurai A.P.S. , Głowacki A.
Published: November 2007

The evolution of permeability hysterisis in Indiana Limestone during application of isotropic confining pressures up to 60 MPa was measured by conducting one‐dimensional constant flow rate tests. These tests were carried out either during monotonic application of the confining pressure or during loading‐partial unloading cycles. Irreversible permeability changes occurred during both monotonic and repeated incremental compression of the limestone. Mathematical relationships are developed for describing the evolution of path‐dependent permeability during isotropic compression.
Evidence in Medicine and Evidence‐Based Medicine
Authors: Worrall John
Published: November 2007

It is surely obvious that medicine, like any other rational activity, must be based on evidence. The interest is in the details: how exactly are the general principles of the logic of evidence to be applied in medicine? Focussing on the development, and current claims of the ‘Evidence‐Based Medicine’ movement, this article raises a number of difficulties with the rationales that have been supplied in particular for the ‘evidence hierarchy’ and for the very special role within that hierarchy of randomized controlled trials (and meta‐analyses of the results of randomized controlled trials). The point is not at all to question the application of a scientific approach to evidence in medicine, but, on the contrary, to indicate a number of areas where philosophers of science can contribute to a proper implementation of exactly that scientific‐evidential approach.
Linguistic Competence without Knowledge of Language
Authors: Collins John
Published: November 2007

Chomsky's competence/performance distinction has been traditionally understood as a distinction between ourknowledgeof language and how we put that knowledge touse. While this construal has its purposes, this article argues that the distinction as Chomsky proposes it depends upon no substantiation of the knowledge locution; rather, the distinction is intended to abstract one system out of an ensemble of systems whose integration underlies performance. The article goes on to assess and reject an argument that the knowledge locution, independent of its traditional construal, is of some substance due to the peculiar evidential base of generative theories.
Comparative study of the effect of luminal hypotonicity on mucosal permeability in rat upper gastrointestinal tract
Authors: Pihl L. , Wilander E. , Nylander O.
Published: November 2007

Aim:  To investigate whether the increase in mucosal permeability in the duodenum, induced by luminal hypotonicity, also occurs in the stomach and the jejunum and whether this increase in permeability can be explained by epithelial injury.

Methods:  The stomach, duodenum or jejunum of the anaesthetized rat were perfused with a hypotonic solution and effects on mucosal permeability (blood‐to‐lumen clearance of radioactive probes); luminal alkalinization and net fluid flux were determined in the absence and presence of cyclooxygenase inhibition.

Results:  The hypotonicity‐induced (50 mm NaCl) increase in duodenal mucosal permeability was markedly larger in cyclooxygenase‐2‐inhibited animals than in controls and associated with a 20% decrease in luminal alkalinization and increased fluid absorption. Perfusion with 50 mm NaCl increased duodenal mucosal permeability to all probes investigated, i.e. 14C‐urea, 14C‐methyl‐d‐glucose, 51Cr‐EDTA and 14C‐inulin. The percentage increase in permeability was the greatest for inulin and the lowest for urea. Luminal hypotonicity caused superficial villous tip damage in some but not in all duodenal specimens but there was no difference in morphology between controls and cyclooxygenase‐2‐inhibited animals. Jejunum, but not the stomach, responded to luminal hypotonicity by increasing net fluid absorption, mucosal permeability (greater than sixfold) and the rate of luminal alkalinization (>100%).

Conclusions:  The stomach does not respond while the jejunum is more sensitive to hypotonicity‐induced increase in mucosal permeability than the duodenum. The hypotonicity‐induced increase in duodenal mucosal permeability most probably constitutes a physiological mechanism that entails widening of paracellular pathways, which facilitates the transport of osmolytes into the lumen.
Artful Cities
Authors: Hall Tim
Published: November 2007

This article explores the various roles that public art has played in the city and the ways in which cultural geographers and others, including critical social scientists and arts critics and advocates, have studied and written about it. It highlights the limitations of existing literatures on public art, discussing in particular their neglect of the study of the audience as a site at which meanings are made. It goes on to highlight ways in which the study of public art in the city might be advanced. In doing so, it considers recent examples of research into public art and the city that have challenged existing orthodoxies.
Reticulated platelets as a marker of platelet recovery after allogeneic stem cell transplantation
Authors: MICHUR H. , MAŚLANKA K. , SZCZEPIŃSKI A. , MARIAŃSKA B.
Published: November 2007

Reticulated platelets (RP) are the youngest forms of platelets in blood and reflect the rate of bone marrow platelet production. In the present study, we used flow cytometric analysis to determine the percentage of RPs in patients undergoing allogeneic stem cell transplantation. We investigated 10 patients after transplantation from HLA identical siblings: five with acute myeloid leukemia (AML), four with chronic myeloid leukemia (CML), and one patient with myelodysplastic syndrome (MDS). Of the patients examined, four patients underwent allogeneic bone marrow transplantation and six patients underwent peripheral blood stem cell transplantation. It was observed that the initially reduced percentage of RPs (2.9 ± 1.7%; mean ± SD) was significantly higher (P = 0.0109) in all patients (13.6 ± 6.4%) in the following 10–26 days. The RP percentage peak preceded the recovery of peripheral platelet count up to 45.6 × 109/l on average by 3 days. We found no difference in RP% between the AML and CML patients but we did observe that in CML patients the RP percentage increased on average 7 days earlier than in AML patients. The elevated RP percentage reflects increased bone marrow regeneration and can be considered an additional marker of thrombopoietic recovery in the patients undergoing allogeneic stem cell transplantation.
Majority and Minority Influence
Authors: Crano William D. , Seyranian Viviane
Published: November 2007

The study of minority influence has advanced considerably since the late 1960s when Moscovici's pioneering efforts brought the minority's role in the process of persuasion and social influence to the forefront. Moscovici's (1980) insight that the underlying processes of majority and minority influence are quite different has been supported, but the steady pace of research has uncovered various unanticipated findings not easily explained by his conversion theory. In this review, we track recent developments and debates in the field, and consider some major explanatory models of minority influence and their differential postulates regarding cognitive processing and attitude change. We pay particular attention to Crano's (2001) leniency contract model, which details the specific conditions under which majorities and minorities impart influence. Finally, we advance some novel postulates regarding the persuasive impact of out‐group minorities.
Dehumanization: A New Perspective
Authors: Haslam Nick , Loughnan Stephen , Reynolds Catherine , Wilson Samuel
Published: November 2007

Dehumanization has traditionally been understood as an extreme form of prejudice that enables violence and cruelty. Recent work indicates that it can also take subtle and everyday forms. We give an overview of early contributions to the psychological study of dehumanization before reviewing recent research on the attribution and denial of humanness. We emphasize our own research program, which proceeds from a theoretical analysis of two distinct senses of humanness, which when denied to others yield two forms of dehumanization. In one form, people are denied uniquely human attributes and likened to animals, and in the other, they are denied essentially human attributes and likened to machines. We discuss the ways in which these two forms of dehumanization are manifest in perceptions of individuals and groups, and speculate on the cognitive and motivational processes involved.
Adult Drug Treatment Courts: A Review
Authors: Jensen Eric L. , Parsons Nicholas L. , Mosher Clayton J.
Published: November 2007

Drug treatment courts (DTCs), an alternative to traditional criminal courts, provide an innovative way to legally process some drug offenders. The origin and recent growth of the drug court system in the USA can be explained as an unintended consequence of a failing ‘war on drugs’. In this article, we discuss the spread of adult DTCs throughout the USA, the main components of drug courts, controversies surrounding DTCs, and some criticisms of drug courts. We summarize the recent evaluations of adult DTCs, and highlight various DTC factors that have been found to reduce individual drug use and criminal activity. We also offer suggestions for future research on DTCs and conclude with policy recommendations.
Genetic predisposition to hypertension sensitizes borderline hypertensive rats to the hypertensive effects of prenatal glucocorticoid exposure
Authors: Bechtold Andrea G. , Vernon Kathy , Hines Tina , Scheuer Deborah A.
Published: November 2007

An adverse intrauterine environment can increase the incidence of hypertension and other cardiovascular disease risk factors. However, in clinical and experimental studies the magnitude of the effect is variable. Possibly, the relative influence of the prenatal environment on cardiovascular disease is determined in part by genetic factors that predispose individuals to the development of environmentally induced hypertension. We tested this hypothesis by comparing the effects of prenatal dexamethasone treatment (Dex, 300 μg kg−1i.p. on days 15 and 16 of gestation) in borderline hypertensive rats (BHR) and control Wistar–Kyoto (WKY) rats. Blood pressure, heart rate and plasma corticosterone values were measured at rest during the middle of the day, and during 1 h of restraint stress in the adult offspring using indwelling arterial catheters implanted at least 4 days prior to data collection. Compared with the saline (vehicle) control treatment, prenatal dexamethasone significantly (P < 0.05) increased baseline mean arterial pressure in male (123 ± 2 versus 131 ± 3 mmHg, saline versus Dex) and female (121 ± 2 versus 130 ± 2 mmHg, saline versus Dex) BHR, but not in male (108 ± 3 versus 113 ± 2 mmHg, saline versus Dex) or female (112 ± 2 versus 110 ± 2 mmHg, saline versus Dex) WKY rats. Relative to saline treatment, prenatal Dex also significantly increased baseline heart rate (328 ± 6 versus 356 ± 5 beats min−1, saline versus Dex) and plasma corticosterone (5 ± 2 versus 24 ± 4 μg dl−1, saline versus Dex), and prolonged the corticosterone response to acute stress, selectively in female BHR. However, prenatal Dex significantly enhanced the arterial pressure response to acute stress only in female WKY, while Dex augmented the elevation in heart rate during stress only in male rats. We conclude that prenatal dexamethasone increased baseline arterial pressure selectively in BHR, and plasma corticosterone only in female BHR. In contrast, prenatal Dex enhanced cardiovascular reactivity to stress in both BHR and WKY rats.
A three pulse phase response curve to three milligrams of melatonin in humans
Authors: Burgess Helen J. , Revell Victoria L. , Eastman Charmane I.
Published: November 2007

Exogenous melatonin is increasingly used for its phase shifting and soporific effects. We generated a three pulse phase response curve (PRC) to exogenous melatonin (3 mg) by administering it to free‐running subjects. Young healthy subjects (n= 27) participated in two 5 day laboratory sessions, each preceded by at least a week of habitual, but fixed sleep. Each 5 day laboratory session started and ended with a phase assessment to measure the circadian rhythm of endogenous melatonin in dim light using 30 min saliva samples. In between were three days in an ultradian dim light (< 150 lux)–dark cycle (LD 2.5 : 1.5) during which each subject took one pill per day at the same clock time (3 mg melatonin or placebo, double blind, counterbalanced). Each individual's phase shift to exogenous melatonin was corrected by subtracting their phase shift to placebo (a free‐run). The resulting PRC has a phase advance portion peaking about 5 h before the dim light melatonin onset, in the afternoon. The phase delay portion peaks about 11 h after the dim light melatonin onset, shortly after the usual time of morning awakening. A dead zone of minimal phase shifts occurred around the first half of habitual sleep. The fitted maximum advance and delay shifts were 1.8 h and 1.3 h, respectively. This new PRC will aid in determining the optimal time to administer exogenous melatonin to achieve desired phase shifts and demonstrates that using exogenous melatonin as a sleep aid at night has minimal phase shifting effects.
Neutralization of a negative charge in the S1–S2 region of the KV7.2 (KCNQ2) channel affects voltage‐dependent activation in neonatal epilepsy
Authors: Wuttke Thomas V. , Penzien Johann , Fauler Michael , Seebohm Guiscard , Lehmann‐Horn Frank , Lerche Holger , Jurkat‐Rott Karin
Published: November 2007

The voltage‐gated potassium channels KV7.2 and KV7.3 (genes KCNQ2 and KCNQ3) constitute a major component of the M‐current controlling the firing rate in many neurons. Mutations within these two channel subunits cause benign familial neonatal convulsions (BFNC). Here we identified a novel BFNC‐causing mutation (E119G) in the S1–S2 region of KV7.2. Electrophysiological investigations in Xenopus oocytes using two‐microelectrode voltage clamping revealed that the steady‐state activation curves for E119G alone and its coexpressions with KV7.2 and/or KV7.3 wild‐type (WT) channels were significantly shifted in the depolarizing direction compared to KV7.2 or KV7.2/KV7.3. These shifts reduced the relative current amplitudes for mutant channels particularly in the subthreshold range of an action potential (about 45% reduction at −50 mV for E119G compared to KV7.2, and 33% for E119G/KV7.3 compared to KV7.2/KV7.3 channels). Activation kinetics were significantly slowed for mutant channels. Our results indicate that small changes in channel gating at subthreshold voltages are sufficient to cause neonatal seizures and demonstrate the importance of the M‐current for this voltage range. This was confirmed by a computer model predicting an increased burst duration for the mutation. On a molecular level, these results reveal a critical role in voltage sensing of the negatively charged E119 in S1–S2 of KV7.2, a region that – according to molecular modelling – might interact with a positive charge in the S4 segment.
Spontaneous and voltage‐activated Ca2+ release in adult mouse skeletal muscle fibres expressing the type 3 ryanodine receptor
Authors: Legrand Claude , Giacomello Emiliana , Berthier Christine , Allard Bruno , Sorrentino Vincenzo , Jacquemond Vincent
Published: November 2007

The physiological properties and role of the type 3 ryanodine receptor (RyR3), a calcium release channel expressed in a wide variety of cell types, remain mysterious. We forced, in vivo, the expression of RyR3 in adult mouse skeletal muscle fibres using a GFP‐RyR3 DNA construct. GFP fluorescence was found within spatially restricted regions of muscle fibres where it exhibited a sarcomere‐related banded pattern consistent with a localization within or near the junctional sarcoplasmic reticulum membrane. Immunostaining confirmed the presence of RyR3 together with RyR1 within the GFP‐positive areas. In ∼90% of RyR3‐positive fibres microinjected with the calcium indicator fluo‐3, we detected repetitive spontaneous transient elevations of intracellular Ca2+ that persisted when fibres were voltage‐clamped at −80 mV. These Ca2+ transients remained essentially confined to the RyR3 expression region. They ranged from wide local events to propagating Ca2+ waves and were in some cases associated with local contractile activity. When voltage‐clamp depolarizations were applied while fluo‐3 or rhod‐2 fluorescence was measured within the RyR3‐expressing region, no voltage‐evoked ‘spark‐like’ elementary Ca2+ release event could be detected. Still global voltage‐activated Ca2+ release exhibited a prominent early peak within the RyR3‐expressing regions. Measurements were also taken from muscles fibres expressing a GFP‐RyR1 construct; positive fibres also yielded a local banded pattern of GFP fluorescence but exhibited no spontaneous Ca2+ release. Results demonstrate that RyR3 is a very potent source of voltage‐independent Ca2+ release activity. Conversely we find no evidence that it could contribute to the production of discrete voltage‐activated Ca2+ release events in differentiated mammalian skeletal muscle.
Towards the Design of an Optimal Energetic Sink in a Strongly Inhomogeneous Two-Degree-of-Freedom System
Authors: Manevitch L. I. , Gourdon E. , Lamarque C. H.
Published: November 2007

Analytical, numerical, and experimental results of energy pumping in a strongly inhomogeneous two-degree-of-freedom system are to be presented in this study. The latter is based both on efficient analytical solution and comparative analysis for various types of energetic sinks. Considering the efficient pumping process as damped beating with strong energy transfer, it is shown that we can design the sinks with amplitude-phase variables which provide the most efficient result. In this study, the main types of energetic sinks are to be compared. Computer simulation has confirmed the analytical predictions which had been obtained. Experimental verification of the analytical prediction is considered for a particular type of sink.
Development of Solid Oxide Fuel Cells and Short Stacks for Mobile Application
Authors: Lang M. , Szabo P. , Ilhan Z. , Cinque S. , Franco T. , Schiller G.
Published: November 2007

At the German Aerospace Center (DLR) in Stuttgart, a lightweight stack design for mobile applications was developed in cooperation with the automotive industry (BMW, Munich; Elring-Klinger, Dettingen; Rhodius, Weissenburg). This concept is based on the application of stamped metal sheet bipolar plates into which porous metallic substrate-supported cells (MSCs) are integrated. The paper concentrates on the one hand on the investigation of plasma sprayed button cells with a diameter of 48mm on porous metallic substrates during reduction/oxidation and thermal cycling. On the other hand, another focus lies in the electrochemical testing of short stacks in the cassette arrangement. The microstructure of the cells was characterized by optical microscopy, scanning electron microscopy (SEM), X-ray diffraction, and energy dispersive microanalysis (EDX) before and after operation. The cells and short stacks were electrochemically characterized mainly by long-term measurements (life cycle), by current-voltage measurements, and by impedance spectroscopy. In order to understand the nature of degradation mechanisms, the open-circuit voltages (OCV), the ohmic resistances, and the polarization resistances, during dynamic operation are compared and discussed. In order to distinguish between degradation effects due to the dynamic operation and usual stationary effects, these values are compared to values of noncycled cells. All of the cells investigated were able to withstand ten redox and ten thermal cycles without severe failure. Their redox- and thermal-cycling behavior are strongly dependent on their OCVs, which decrease during cycling. This proves that thermomechanical stresses in the electrolyte layer play a major role for the electrochemical performance of the cells during cycling. The improvement of the electrodes during the first 200h of operation and the ohmic resistance of the cells are not significantly influenced by the cycling. The first four-cell short stack with the cassette arrangement shows promising results with an OCV of ∼4V and an overall power of 92W at 800°C. The performances of the single cells are in the range of 180–220mW∕cm2. The differences in cell performance can be attributed to different polarization resistances of the cells in the cassettes, which might be caused by a nonuniform gas supply in the short stack.
Investigation of Atomistic Scale Transport Phenomena of the Proton Exchange Membrane Fuel Cell
Authors: Cheng Chin-Hsien , Hong Che-Wun
Published: November 2007

This paper studies the transport phenomena inside the electrolyte of proton exchange membrane fuel cells (PEMFCs) using atomistic simulation techniques. The investigated material of the electrolyte is Nafion®, which is the most widely adapted polymer membrane in low-temperature fuel cells. The molecular dynamics simulation system includes part of the Nafion structure, numerous water molecules, and the transporting cations. The cations are assumed to be hydroxoniums (H3O+), which are a hydrogen proton combined with a water molecule. Simulation results indicated that the electrostatic energy dominated the other potential energies in the total internal energy analysis. Clusters of water molecules tend to move toward the sulfonic acid group in the Nafion fragment, where the hydrophilic/hydrophobic characteristics can be observed. The transport phenomena of hydroxoniums are classified into two categories—continuous migration and noncontinuous hopping. The self-diffusion coefficients of the hydroxoniums and the water molecules in the membrane were evaluated to be 3.476×10−5cm2∕s and 4.993×10−5cm2∕s respectively, based on the Einstein relation. The calculated self-diffusion coefficients are of the same order of magnitude as the experimental results, which indicates this atomistic simulation is reaching more and more practical in engineering analysis.
Modeling of a Solid Oxide Fuel Cell Fueled by Methane: Analysis of Carbon Deposition
Authors: Klein J.-M. , Bultel Y. , Pons M. , Ozil P.
Published: November 2007

Natural gas appears to be a fuel of great interest for solid oxide fuel cell (SOFC) systems. It mainly consists of methane, which can be converted into hydrogen by direct internal reforming (DIR) within the SOFC anode. However, a major limitation to DIR is carbon formation within the ceramic layers at intermediate temperatures. This paper proposes a model solution using the CFD-ACE software package to simulate the behavior of a tubular SOFC. A detailed thermodynamic analysis is carried out to predict the boundary of carbon formation for SOFCs fueled by methane. Thermodynamic equilibrium calculations that take into account Boudouard and methane cracking reactions allow us to investigate the occurrence of carbon formation. This possibility is discussed from the values of driving forces for carbon deposition defined as α=PCO2∕(KBPCO2) and β=PH22∕(KCPCH4), from the equilibrium constants KB and KC of the Boudouard and cracking reactions, and from the partial pressure Pi of species i. Simulations allow the calculation of the distributions of partial pressures for all the gas species (CH4, H2, CO, CO2, and H2O), current densities, and potentials of both electronic and ionic phases within the anode part (i.e., gas channel and Cermet anode). Finally, a mapping of α and β values enables us to predict the predominant zones where carbon formation is favorable (α or β<1) or unfavorable (α or β>1) according to the calculation based on thermodynamic equilibrium. With regard to the values of these different coefficients, we can say that a carbon formation can be supposed for temperature less than 800°C and for ratios xH2O∕xCH4 smaller than 1.
Doctor Julius Robert Mayer and Energy Processes in Living Systems
Authors: Erlichson Herman
Published: November 2007

The overwhelming majority of important papers in physics are written by physicists. But the physician Julius Robert Mayer (1814–1878, see photo) did a valid theoretical calculation of the mechanical equivalent of heat just before Joule reported on his results from his well-known paddle-wheel experiments. Joule is well-known to physics people and Mayer is a relatively obscure and unknown name. Joule was part of the physics establishment; Mayer was not. Joule's paddle-wheel experiments were easy to understand, and physics people appreciated the painstaking manner in which he made corrections in his experiments. The fame of Joule is well-deserved. On the other hand, Mayer's work is not traditional and there will almost certainly never be a Mayer physics laboratory experiment. We can admire the tenacity with which Mayer pushed his priority case, but that is all.
Fresnel's Lighthouse Lenses
Authors: Greenslade Thomas B.
Published: November 2007

One of the rewards of walking up the scores of steps winding around the inside of the shaft of a lighthouse is turning inward and examining the glass optical system. This arrangement of prisms, lenses, and reflectors is used to project the light from a relatively small source in a beam that can be seen far at sea.
The Challenge of Teaching Introductory Physics to Premedical Students
Authors: Kortemeyer Gerd
Published: November 2007

Most physics instructors are motivated by a genuine interest in their subject area and in using physics to understand real-world phenomena. While many premedical students may share these interests, most are motivated by fulfilling their degree requirements and gaining admittance into medical school. To achieve this latter goal, they need excellent grades and have to do well on the Medical College Admissions Test (MCAT),1 which includes a physical sciences section that may not coincide with the learning goals of many physics courses. Too often both sides simply give up, and courses come to some kind of unspoken agreement of how to go through the motions of completing the course with the least amount of mutual aggravation, while real physics falls by the wayside. But how exactly does this discrepancy manifest itself, and what—if anything other than giving up—can be done about it? In this paper, I first survey learner beliefs, expectations, and preferences and then attempt to identify approaches and resources that may partly address the identified issues.
Measurement and Demonstration of Thermal Expansion Coefficient
Authors: Inbanathan S. S. R. , Moorthy K. , Balasubramanian G.
Published: November 2007

There are many classroom demonstrations, such as the ball-and-ring experiment, for showing the existence of thermal expansion of solids. The coefficient of linear expansion α (= increase in length divided by the original length times the change in temperature) may be measured in high school laboratories using a number of methods.1–4 In this paper we describe an especially simple experiment for determining α for a metal rod. It is based on the well-known optical lever method and is suitable for either a laboratory experiment or a classroom exercise.
Scleractinian Coral Species Survive and Recover from Decalcification
Authors: Fine Maoz , Tchernov Dan
Published: November 2007

Anthropogenic-driven accumulation of carbon dioxide in the atmosphere and projected ocean acidification have raised concerns regarding the eventual impact on coral reefs. This study demonstrates that skeleton-producing corals grown in acidified experimental conditions are able to sustain basic life functions, including reproductive ability, in a sea anemone‐like form and will resume skeleton building when reintroduced to normal modern marine conditions. These results support the existence of physiological refugia, allowing corals to alternate between nonfossilizing soft-body ecophenotypes and fossilizing skeletal forms in response to changes in ocean chemistry. This refugia, however, does not undermine the threats to reef ecosystems in a high carbon dioxide world.
Self-Organization, Embodiment, and Biologically Inspired Robotics
Authors: Pfeifer Rolf , Lungarella Max , Iida Fumiya
Published: November 2007

Robotics researchers increasingly agree that ideas from biology and self-organization can strongly benefit the design of autonomous robots. Biological organisms have evolved to perform and survive in a world characterized by rapid changes, high uncertainty, indefinite richness, and limited availability of information. Industrial robots, in contrast, operate in highly controlled environments with no or very little uncertainty. Although many challenges remain, concepts from biologically inspired (bio-inspired) robotics will eventually enable researchers to engineer machines for the real world that possess at least some of the desirable properties of biological organisms, such as adaptivity, robustness, versatility, and agility.
The
Arabidopsis
Circadian Clock Incorporates a cADPR-Based Feedback Loop
Authors: Dodd Antony N. , Gardner Michael J. , Hotta Carlos T. , Hubbard Katharine E. , Dalchau Neil , Love John , Assie Jean-Maurice , Robertson Fiona C. , Jakobsen Mia Kyed , Gonçalves Jorge , Sanders Dale , Webb Alex A. R.
Published: November 2007

Transcriptional feedback loops are a feature of circadian clocks in both animals and plants. We show that the plant circadian clock also incorporates the cytosolic signaling molecule cyclic adenosine diphosphate ribose (cADPR). cADPR modulates the circadian oscillator's transcriptional feedback loops and drives circadian oscillations of Ca
2+
release. The effects of antagonists of cADPR signaling, manipulation of cADPR synthesis, and mathematical simulation of the interaction of cADPR with the circadian clock indicate that cADPR forms a feedback loop within the plant circadian clock.
Time-Dependent Central Compensatory Mechanisms of Finger Dexterity After Spinal Cord Injury
Authors: Nishimura Yukio , Onoe Hirotaka , Morichika Yosuke , Perfiliev Sergei , Tsukada Hideo , Isa Tadashi
Published: November 2007

Transection of the direct cortico-motoneuronal pathway at the mid-cervical segment of the spinal cord in the macaque monkey results in a transient impairment of finger movements. Finger dexterity recovers within a few months. Combined brain imaging and reversible pharmacological inactivation of motor cortical regions suggest that the recovery involves the bilateral primary motor cortex during the early recovery stage and more extensive regions of the contralesional primary motor cortex and bilateral premotor cortex during the late recovery stage. These changes in the activation pattern of frontal motor-related areas represent an adaptive strategy for functional compensation after spinal cord injury.
Comparison of examination of the entire uterine cervix with routine cervical sampling in hysterectomy specimens from women with endometrial cancer: Table 1
Authors: Nayar A G , Cross P A , Bulmer J N , Deen S , El-Sherif A
Published: November 2007

Background:

Cervical involvement by endometrial cancer alters the FIGO stage and determines clinical management, but there are no accepted guidelines for cervical sampling of these cases.

Aim:

To assess whether sampling more than two “routine” blocks of the cervix (anterior and posterior) alters the pathological staging of hysterectomy specimens for endometrial cancer.

Methods:

Histological involvement of the cervix was prospectively compared in hysterectomies performed for proven endometrial cancer (n = 61). Specimens had two “routine” blocks taken from anterior and posterior cervix; all of the remaining cervix was also processed for histological assessment.

Results:

61 cases of endometrial cancer had the entire uterine cervix processed. There were 54 cases of endometrioid adenocarcinoma and 7 special types. Twelve cases had cervical involvement (stage 2A or 2B), and seven cases were stage 3A or above, of which three also had cervical involvement. In none of the 61 cases did the additional cervical blocks (n = 544) taken alter the staging made on the “routine” blocks.

Conclusion:

Sampling of two blocks from the cervix appears sufficient for histological staging of endometrial cancer in hysterectomy specimens.
Polar vineyard pruning extracts increase the activity of the main ligninolytic enzymes in Lentinula edodes cultures
Authors: Harris-Valle Citlalli , Esqueda Martín , Sánchez Alfonso , Beltrán-García Miguel , Valenzuela-Soto Elisa M.
Published: November 2007

Lentinula edodes is considered an alternative recycling agent for agricultural wastes, and there have been several studies to understand the relationship between its growth and ligninolytic activity. We tested the effect of wood from viticulture pruning, extracted with solvents of differing polarity, on the biomass production and activity pattern of ligninolytic enzymes. The analysis was done by measuring the mycelial dry mass and enzyme activity of liquid growth medium during the culture of L. edodes, adding either single extracts or a combination of extracts. Polar extracts enhanced mycelial production, and the activity patterns of lignin peroxidase, manganese peroxidase, aryl alcohol oxidase, and laccase were comparable to their activities predicted by ligninolysis models proposed for other fungi. We conclude that the polar extracts could be useful for enhancing fungal biomass production and for modifying lignin degradation because the regulation of ligninolytic enzyme activity is differentially influenced by the polarity of the extract.
Production of active pediocin PA-1 inEscherichia coliusing a thioredoxin gene fusion expression approach: cloning, expression, purification, and characterization
Authors: Beaulieu Lucie , Tolkatchev Dmitri , Jetté Jean-François , Groleau Denis , Subirade Muriel
Published: November 2007

Antimicrobial peptides possess cationic and amphipathic properties that allow for interactions with the membrane of living cells. Bacteriocins from lactic acid bacteria, in particular, are currently being studied for their potential use as food preservatives and for applications in health care. However, bacteriocin exploitation is often limited owing to low production yields. Gene cloning and heterologous protein or peptide production is one way to possibly achieve overexpression of bacteriocins to support biochemical studies. In this work, production of recombinant active pediocin PA-1 (PedA) was accomplished in Escherichia coli using a thioredoxin (trx) gene fusion (trx–pedA) expression approach. Trx–PedA itself did not show any biological activity, but upon cleavage by an enterokinase, biologically active pediocin PA-1 was obtained. Recombinant pediocin PA-1 characteristics (molecular mass, biological activity, physicochemical properties) were very similar to those of native pediocin PA-1. In addition, a 4- to 5-fold increase in production yield was obtained, by comparison with the PA-1 produced naturally by Pediococcus acidilactici PAC 1.0. The new production method, although not optimized, offers great potential for supporting further investigations on pediocin PA-1 and as a first-generation process for the production of pediocin PA-1 for high-value applications.
Impairment of cobalt-induced riboflavin biosynthesis in aDebaryomyces hanseniimutant
Authors: Seda-Miró Jasmine M. , Arroyo-González Nancy , Pérez-Matos Ana , Govind Nadathur S.
Published: November 2007

Flavinogenic yeasts such as Debaryomyces hansenii overproduce riboflavin (RF) in the presence of heavy metals. Growth and RF production were compared between wild-type D. hansenii and a RF production-impaired metal-tolerant ura3 mutant in the presence of sublethal cobalt(II) concentrations. Debaryomyces hansenii (wild type) exhibits an extended lag phase with an increase in RF synthesis. Supplementation of exogenous uracil shortened the lag phase at the highest concentration of cobalt(II) used, suggesting that uracil has a possible role in metal acclimation. The D. hansenii ura3 mutant isolated by chemical mutagenesis exhibited a higher level of metal tolerance, no extended lag phase, and no marked increase in RF synthesis. Transformation of the mutant with the URA3 gene isolated from Saccharyomyces cerevisiae or D. hansenii did not restore wild-type characteristics, suggesting a second mutation that impairs RF oversynthesis. Our results demonstrate that growth, metal sensitivity, and RF biosynthesis are linked.
Amino acid pool composition of the basidiomyceteCoprinus cinereus
Authors: Ulrich Cynthia E. , Gathman Allen C. , Lilly Walt W.
Published: November 2007

The leaf-litter fungus Coprinus cinereus maintains a pool of free amino acid in its mycelium. When the organism is grown under conditions of high nitrogen availability with 13.2 mmol·L–1l-asparagine as the nitrogen source, the primary constituents of this pool are glutamine, alanine, and glutamic acid. Together these 3 amino acids comprise approximately 70% of the pool. Nitrogen deprivation reduces the size of the free amino acid pool by 75%, and neither a high concentration of ammonium nor a protein nitrogen source support a similar pool size as l-asparagine. Nitrogen deprivation also reduces the concentration of glutamine to the pool while increasing glutamate. Concomitant with this shift is a marked increase in mycelial ammonium.
Topic tracking based on bilingual comparable corpora and semisupervised clustering
Authors: Fukumoto Fumiyo , Suzuki Yoshimi
Published: November 2007

In this paper, we address the problem of
skewed data
in topic tracking: the small number of stories labeled positive as compared to negative stories and propose a method for estimating effective training stories for the topic-tracking task. For a small number of labeled positive stories, we use bilingual comparable, i.e., English, and Japanese corpora, together with the EDR bilingual dictionary, and extract story pairs consisting of positive and associated stories. To overcome the problem of a large number of labeled negative stories, we classified them into clusters. This is done using a semisupervised clustering algorithm, combining
k
means with EM. The method was tested on the TDT English corpus and the results showed that the system works well when the topic under tracking is talking about an event originating in the source language country, even for a small number of initial positive training stories.
A framework for real-time utilities for Ada 2005
Authors: Wellings A. J. , Burns A.
Published: November 2007

Modernlarge real-time systems are becoming more complex. Whilst Ada 2005 provides a comprehensive set of programming mechanisms that allow these systems to be implemented, the abstractions are low level. This paper argues that there is a need for a standardised library of real-time utilities that address common real-time problems.
Implementing the new Ada 2005 real-time features on a bare board kernel
Authors: Urueña Santiago , Pulido José , Redondo José , Zamorano Juan
Published: November 2007

A real-time kernel providing timing services is a key component of any real-time system. The current revision of the Ada standard provides a range of real-time mechanisms that can be used to ensure the required temporal behaviour of real-time tasks. However, kernel timing services must be implemented carefully in order to avoid overheads and inaccuracies. This paper describes the implementation of the Ada timing services in an evolved version of the Open Ravenscar Kernel. The interrelation among the different timing mechanisms is also analysed and evaluated.
Operating system support for execution time budgets for thread groups
Authors: Rivas Mario Aldea , Harbour Michael González
Published: November 2007

The recent Ada 2005 standard introduced a number of new real-time services, with the capability of creating and managing execution time budgets for groups of tasks. This capability has many practical applications in real-time systems in general, and therefore it is also interesting for real-time operating systems. In this paper we present an implementation of thread group budgets inside a POSIX real-operating system, which can be used to implement the new Ada 2005 services. The architecture and details of the implementation are shown, as they may be useful to other implementers of this functionality defined in the new standard.
Introduction
Authors: Real Jorge , Michell Stephen
Published: November 2007

To consider future directions in computing, and what changes would be required for Ada to effectively use new features.
Suggestions for stream based parallel systems in Ada
Authors: Ward M. , Audsley N. C.
Published: November 2007

Ada provides good support for the implementation of dependable, real-time, control systems. However, its support for other styles of systems is not as good. This paper explores the support available for implementing parallel, stream based systems.

The paper presents an implementation of an image manipulation system which highlights deficiencies in the support for such systems in the Ada language. Two additional semantics are proposed for addition to the Ada language which will provide for the needs of these systems. The broadcast semantic allows the same data to be written to several POs simultaneously. The guarded protected function semantic permits several readers to wait on an entry and simultaneously read data from the PO.
Interfacing Ada to operating systems
Authors: Michell Stephen
Published: November 2007

This paper examines approaches used by the Ada programming language to interface to explicit operating system services such as events and sockets. We examine the potential for updating a specific interface, the POSIX Ada binding, to a more gereral interface to operating systems services. An approach is proposed to unify classes of services such as synchronous and asynchronous file IO in such an interface.
Summary
Authors: de la Puente Juan A. , Urueña Santiago
Published: November 2007

The final session summarized the main conclusions of the workshop and addressed some open issues. Another objective was to decide whether a new IRTAW is needed, and, if so, the location and time frame.
The role of microprogramming in the computer science curriculum
Authors: Rosin R. F. , Frieder G.
Published: November 2007

Microprogramming is viewed as a concept and technology which has its greatest meaning when applied to the implementation of entire computer systems, as opposed to its usage in computer control units alone. Rather than being presented on a stand-alone basis, microprogramming should be treated as just one important alternative in all computer science courses which deal with computer system implementation, whether such systems are conceived in hardware, software, or a combination of the two. Examples are shown of the appearance of microprogramming in a variety of such courses.