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Selected AbstractsAn Evaluation of Flexible Workday Policies in Job Shops,DECISION SCIENCES, Issue 2 2002Kum-Khiong Yang ABSTRACT Job shops have long faced pressures for improvement in a challenging and volatile environment. Today's trends of global competition and shortening of product life cycles suggest that both the challenges and the intensity of market volatility will only increase. Consequently, the study of tactics for maximizing the flexibility and responsiveness of a job shop is important. Indeed, there is a significant body of literature that has produced guidelines on when and how to deploy tactics such as alternate routings for jobs and transfers of cross-trained workers between machines. In this paper we consider a different tactic by adjusting the length of workdays. Hours in excess of a 40-hour week are exchanged for compensatory time off at time and a half, and the total amount of accrued compensatory time is limited to no more than 160 hours in accordance with pending legislation. We propose several simple flexible workday policies that are based on an input/output control approach and investigate their performance in a simulated job shop. We find significant gains in performance over a fixed schedule of eight hours per day. Our results also provide insights into the selection of policy parameters. [source] Rural men and mental health: Their experiences and how they managedINTERNATIONAL JOURNAL OF MENTAL HEALTH NURSING, Issue 5 2007Don Gorman ABSTRACT:, There is a growing awareness that a primary source of information about mental health lies with the consumers. This paper reports on a study that interviewed rural men with the aim of exploring their mental health experiences within a rural environment. The results of the interviews are a number of stories of resilience and survival that highlight not only the importance of exploring the individuals' perspective of their issues, but also of acknowledging and drawing on their inner strengths. Rural men face a number of challenges that not only increase the risk of mental illness but also decrease the likelihood of them seeking and/or finding professional support. These men's stories, while different from each other, have a common thread of coping. Despite some support from family and friends, participants also acknowledged that seeking out professional support could have made the recovery phase easier. Mental health nurses need to be aware, not only of the barrier to professional support but also of the significant resilience that individuals have and how it can be used. [source] Temperature influences walking speed and walking activity of Trichogramma brassicae (Hym., Trichogrammatidae)JOURNAL OF APPLIED ENTOMOLOGY, Issue 6 2001B. P. Suverkropp Walking speeds and walking activities (walking time divided by total time) of Trichogramma brassicae were determined at 12, 16, 20 and 25°C. Walking speed was measured during a 5-min period, and walking activity over a 4-day period. Both walking speed and walking activity were strongly influenced by temperature. Walking speed increased linearly with the temperature and was twice as high at 20 as at 12°C. At 25°C, walking activity was high during the whole day, at 20 and 16°C it decreased during the afternoon, whereas at 12°C the wasps became most active only at noon or later. At low temperatures, there was a strong individual variation in walking activity. At 25°C, T. brassicae was active most of the time, so the area searched per time unit can only increase at temperatures above 25°C if walking speed increases. At temperatures below 20°C, searching was more restricted by low walking activity than by low walking speed. Even disregarding other effects of temperature, the reduction in walking speed and walking activity at suboptimal temperatures means that T. brassicae can only search half of the area at 20°C, and only one-seventh at 15°C that it can search at 25°C. [source] Lactate transport and transporters: General principles and functional roles in brain cellsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 1-2 2005Leif Hertz Abstract Lactate is transported across cell membranes by diffusional, saturable cotransport with protons, mediated by monocarboxylate transporters (MCTs). This transport is bidirectional and in the absence of a transcellular H+ gradient, it can increase the intracellular concentration of lactate up to but not beyond the extracellular level (or vice versa). If extra- and intracellular pH differ, however, the equilibrium level is determined by the gradients of both lactate anions and protons. Rates of lactate uptake are determined most often by measuring uptake of labeled lactate, e.g., [U- 14C]lactate. In the case of lactate and other compounds that are metabolized, errors are introduced easily because continuing inwardly directed diffusional net transport of label can be achieved by intracellular metabolism, reducing the intracellular level of the nonmetabolized lactate and thus maintaining a concentration gradient between extra- and intracellular concentrations of the nonmetabolized compound (metabolism-driven uptake). For measurement of facilitated diffusion kinetics, it is essential that the period during which the uptake is measured is short enough that little or no metabolism-driven uptake contributes to the measured uptake (or that first-order regression analysis is carried out to obtain initial uptake rates from nonlinear traces). To achieve initial uptake rates, incubation periods well below 1 min are generally required. Lactate uptake is fast in astrocytes, which express powerful, low-affinity MCTs, i.e., MCT1 and MCT4. Due to the low affinity of these transporters, they respond to increased lactate gradients with enhanced transporter activity. The predominant MCT in neurons is the high-affinity MCT2, which can only increase its activity to a limited extent in the face of an increased lactate gradient. This is reflected by a high-affinity lactate uptake, although most investigators also have demonstrated a component of lactate uptake with lower affinity. In both neurons and astrocytes, however, facilitated diffusion is fast enough that under most conditions lactate fluxes will be determined mainly by the rate of metabolism-driven uptake, and MCT-mediated transport only will be rate-limiting after establishment of large transmembrane gradients. © 2004 Wiley-Liss, Inc. [source] Manipulating sex ratios for conservation: short-term risks and long-term benefitsANIMAL CONSERVATION, Issue 1 2002C. Wedekind Manipulating family sex ratio is often possible, either through non-invasive methods like changing sex-determining ecological or social factors, or through more invasive methods such as hormone treatment of embryos or sperm sexing prior to using assisted reproductive technologies. If the number of available eggs limits population growth, the production of relatively more daughters than sons may eventually lead to increased population growth in terms of absolute numbers. However, any deviation of the effective sex ratio from equality increases the rate of inbreeding and the loss of genetic variance in the next generation. I show here that there is a range of female biased sex ratios where increased population growth outweighs the effect of an enhanced inbreeding rate during the first generation or the first few generations after the start of a sex ratio manipulation programme. This is especially so in small and declining populations, where some sex ratio manipulations not only increase the effective population number Ne, but also shift the population quickly into population numbers that are safe against the Allee effect. Consequently, an optimal sex ratio manipulation with respect to the genetic quality of a population means sending an endangered population first through a genetic bottleneck to achieve increased Ne, and hence decreased rates of inbreeding, in the long run. [source] Generating isomorphous heavy-atom derivatives by a quick-soak method.ACTA CRYSTALLOGRAPHICA SECTION D, Issue 7 2002Part I: test cases Screening for heavy-atom derivatives remains a time-consuming and cumbersome process that often results in non-isomorphous derivatives whose phases cannot be combined. Using lysozyme and Fc,RIII receptor crystals as test cases, an improved soaking method for the generation of conventional heavy-atom derivatives has been developed. The method is based on soaking crystals in heavy-atom compounds for a very brief time at near-saturation concentrations. Compared with the current heavy-atom soaking method, which often takes days to achieve a derivatization, the quick-soak method completes a derivatization within 10,min to 2,h. The bound heavy-atom sites display higher peak heights from quick soaks than from overnight soaks in all cases tested. The quick-soak derivatives also preserved native-like diffraction resolution and data quality that was better than the prolonged-soak derivatives. Furthermore, derivatives generated by brief soaks are more isomorphous to the native than those generated by overnight soaks. Short soaks not only increase the likelihood of success in heavy-atom screening by reducing the pitfalls associated with prolonged soaks, such as lack of isomorphism and overall lattice disorder, but also have the potential to transform a time-consuming derivative screening into an `on-the-fly' real-time derivatization process. [source] Filaggrin null mutations increase the risk and persistence of hand eczema in subjects with atopic dermatitis: results from a general population studyBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2010J.P. Thyssen Summary Background, Hand eczema is prevalent in the general population. It remains unclear whether or not filaggrin gene (FLG) null mutations increase the overall risk of hand eczema or only increase the risk of hand eczema in subjects with atopic dermatitis. Objectives, To investigate the association between FLG null mutations and hand eczema. Methods, A random sample of 3335 adults from the general population in Denmark was patch tested, FLG genotyped for R501X and 2282del4 null mutations and questioned about hand eczema. Results, Participants with combined presence of atopic dermatitis and FLG null mutation status had a significantly higher prevalence of hand eczema, an earlier onset of hand eczema and a higher persistence of hand eczema compared with subjects with normal FLG status and absence of atopic dermatitis. Logistic regression analyses revealed positive associations between hand eczema within the past 12 months and FLG null mutation status in participants with a history of atopic dermatitis [odds ratio (OR) 2·98; 95% confidence interval (CI) 1·27,7·01], but not in subjects without atopic dermatitis (OR 0·82; 95% CI 0·41,1·67). Conclusions,FLG null mutations were significantly associated with hand eczema (< 12 months) in subjects with atopic dermatitis. Combined atopic dermatitis and filaggrin null mutation status was strongly associated with early onset of hand eczema and hand eczema persistence. [source] Risk of emotional disorder in offspring of depressed parents: gender differences in the effect of a second emotionally affected parentDEPRESSION AND ANXIETY, Issue 8 2008Karlien M.C. Landman-Peeters M.A. Abstract In offspring of depressed parents a second parent with emotional problems is likely to increase risk of emotional disorder. This effect may however differ between sons and daughters and between offspring of depressed fathers and offspring of depressed mothers. In adolescent and young-adult offspring of parents with major depressive disorder, this study examined the effects of a second affected parent, offspring gender, gender of the depressed parent and their interactions on risk of depression and anxiety disorder. We found that daughters had a higher risk of depression and anxiety than sons and that offspring of depressed mothers had a higher risk of anxiety than offspring of depressed fathers. In addition to these main effects, we found an interaction between parent and offspring gender inasmuch that sons of depressed fathers had the lowest risk of depression and anxiety relative to the other groups. A second affected parent tended to increase risk of depression and significantly increased risk of anxiety. However, this effect of a second affected parent on offspring anxiety was most prominent in daughters when the second affected parent was the father, whereas risk in sons did not increase if the father was affected as well. Our results indicate that paternal and maternal depression similarly and additively increase daughters' risk of emotional disorder, but that sons' risk only increases with maternal depression. Intergenerational transmission of emotional disorder seems strongest when the female gender is involved, either in the form of a daughter or a depressed mother. Depression and Anxiety 0:1,8, 2007. © 2007 Wiley-Liss, Inc. [source] Silicon Inverse-Opal-Based Macroporous Materials as Negative Electrodes for Lithium Ion BatteriesADVANCED FUNCTIONAL MATERIALS, Issue 12 2009Alexei Esmanski Abstract Several types of silicon-based inverse-opal films are synthesized, characterized by a range of experimental techniques, and studied in terms of electrochemical performance. Amorphous silicon inverse opals are fabricated via chemical vapor deposition. Galvanostatic cycling demonstrates that these materials possess high capacities and reasonable capacity retentions. Amorphous silicon inverse opals perform unsatisfactorily at high rates due to the low conductivity of silicon. The conductivity of silicon inverse opals can be improved by their crystallization. Nanocrystalline silicon inverse opals demonstrate much better rate capabilities but the capacities fade to zero after several cycles. Silicon,carbon composite inverse-opal materials are synthesized by depositing a thin layer of carbon via pyrolysis of a sucrose-based precursor onto the silicon inverse opals. The amount of carbon deposited proves to be insufficient to stabilize the structures and silicon,carbon composites demonstrate unsatisfactory electrochemical behavior. Carbon inverse opals are coated with amorphous silicon producing another type of macroporous composite. These electrodes demonstrate significant improvement both in capacity retentions and in rate capabilities. The inner carbon matrix not only increases the material conductivity but also results in lower silicon pulverization during cycling. [source] Systemverhalten und Prozessoptimierung beim ErddruckschildGEOMECHANICS AND TUNNELLING, Issue 3 2008Ulrich Maidl Dr.-Ing. Eine konsequente Analyse der Prozessdaten kann die Sicherheit, aber auch die Effektivität des Ressourceneinsatzes beim hoch technisierten Schildvortrieb erheblich steigern. Präventive Maßnahmen zur Prozessoptimierung können durch die zeitnahe Analyse des Systemverhaltens während des Bauablaufs rechtzeitig eingeleitet werden. Eine Analyse des Systemverhaltens wird durch die Aufspaltung des Bauablaufs in Teilprozesse und die Definition der Schlüsselprozesse möglich. Im folgenden Artikel wird am Beispiel des Erddruckschilds aufgezeigt, wie beim heutigen Stand der Technik Prozesse realitätsnah simuliert und während der Ausführung unter Einsatz der vorhandenen Mess- und Datenerfassungstechnik analysiert werden können. System Behaviour and Process Optimization at EPB Shield A consistent analysis of the process parameters in highly mechanised shield tunnelling, not only increases the safety, but it also improves the efficiency of the resources in action. The real time analysis of the system's behaviour allows to timely carry out preventive measures during the construction process with the aim of optimizing the construction process. The analysis of the system's behaviour is possible by splitting the construction sequence in a series of partial processes and by defining the key processes. The present paper represents an EPB shield study case, which shows how the present state of the art allows simulating processes realistically during construction, by applying existing monitoring and data registration technology. [source] Inter-annual variation in primary production of a semi-arid grassland related to previous-year productionJOURNAL OF VEGETATION SCIENCE, Issue 1 2001Martín Oesterheld Mean annual precipitation accounts for a large proportion of the variation in mean above-ground net primary production (ANPP) of grasslands worldwide. However, the inter-annual variation in production in any grassland site is only loosely correlated with precipitation. The longest record of variation in production and precipitation for a site corresponds to a shortgrass steppe in Colorado, USA. A previous study of this record showed that current-year precipitation accounted for 39% of the inter-annual variation in ANPP. In this note, we show that ca. one third of the unexplained variation is related to previous-year ANPP: ANPP per mm of precipitation was higher in years preceded by wet, more productive years than in years preceded by average years; similarly, ANPP per mm of precipitation was lower in years preceded by dry, less productive years than in years preceded by average years. Since previous-year ANPP was, in turn, associated with precipitation of a year before, current-year ANPP was also explained by precipitation of two previous years. Our finding not only increases our predictive ability, but it also changes our understanding of how ANPP responds to fluctuations in precipitation. If ANPP is thought to vary according to current-year precipitation only, it will simply track annual precipitation in time. According to this new result, however, ANPP fluctuations are buffered if wet, more productive years alternate with dry, less productive years, and they are amplified if wet or dry sequences of several years take place. [source] The effect of stoichiometry on the fracture toughness of a liquid crystalline epoxyPOLYMER ENGINEERING & SCIENCE, Issue 2 2002Elizabeth J. Robinson The fracture toughness of a liquid crystalline epoxy was compared with that of a standard bisphenol-A based epoxy to understand how both the liquid crystalline structure and the crosslink density affect fracture toughness. For the liquid crystalline epoxy, the liquid crystalline domain size decreased with increasing temperature of cure and away from the stoichiometric formulation. Quantitative fractography showed that there is a competition between the liquid crystalline domain structure and the stoichiometry in determining the fracture toughness. At some cure conditions the effect of the domains is dominant. When the cure conditions are adjusted to reduce the domain size, the domains become too small to affect the fracture toughness, and thus the effect of the stoichiometry is dominant. The result is that the formation of liquid crystalline structure only increases the fracture toughness relative to that of a traditional epoxy at and near the stoichiometric formulation. [source] Evaluation of a large-eddy model simulation of a mixed-phase altocumulus cloud using microwave radiometer, lidar and Doppler radar dataTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 618 2006J. H. Marsham Abstract Using the Met Office large-eddy model (LEM) we simulate a mixed-phase altocumulus cloud that was observed from Chilbolton in southern England by a 94 GHz Doppler radar, a 905 nm lidar, a dual-wavelength microwave radiometer and also by four radiosondes. It is important to test and evaluate such simulations with observations, since there are significant differences between results from different cloud-resolving models for ice clouds. Simulating the Doppler radar and lidar data within the LEM allows us to compare observed and modelled quantities directly, and allows us to explore the relationships between observed and unobserved variables. For general-circulation models, which currently tend to give poor representations of mixed-phase clouds, the case shows the importance of using: (i) separate prognostic ice and liquid water, (ii) a vertical resolution that captures the thin layers of liquid water, and (iii) an accurate representation the subgrid vertical velocities that allow liquid water to form. It is shown that large-scale ascents and descents are significant for this case, and so the horizontally averaged LEM profiles are relaxed towards observed profiles to account for these. The LEM simulation then gives a reasonable cloud, with an ice-water path approximately two thirds of that observed, with liquid water at the cloud top, as observed. However, the liquid-water cells that form in the updraughts at cloud top in the LEM have liquid-water paths (LWPs) up to half those observed, and there are too few cells, giving a mean LWP five to ten times smaller than observed. In reality, ice nucleation and fallout may deplete ice-nuclei concentrations at the cloud top, allowing more liquid water to form there, but this process is not represented in the model. Decreasing the heterogeneous nucleation rate in the LEM increased the LWP, which supports this hypothesis. The LEM captures the increase in the standard deviation in Doppler velocities (and so vertical winds) with height, but values are 1.5 to 4 times smaller than observed (although values are larger in an unforced model run, this only increases the modelled LWP by a factor of approximately two). The LEM data show that, for values larger than approximately 12 cm s,1, the standard deviation in Doppler velocities provides an almost unbiased estimate of the standard deviation in vertical winds, but provides an overestimate for smaller values. Time-smoothing the observed Doppler velocities and modelled mass-squared-weighted fallspeeds shows that observed fallspeeds are approximately two-thirds of the modelled values. Decreasing the modelled fallspeeds to those observed increases the modelled IWC, giving an IWP 1.6 times that observed. Copyright © 2006 Royal Meteorological Society [source] Snake venom hyaluronidase: a therapeutic targetCELL BIOCHEMISTRY AND FUNCTION, Issue 1 2006K. Kemparaju Abstract The diffusion of toxins from the site of a bite into the circulation is essential for successful envenomation. Degradation of hyaluronic acid in the extracellular matrix (ECM) by venom hyaluronidase is a key factor in this diffusion. Hyaluronidase not only increases the potency of other toxins but also damages the local tissue. In spite of its important role, little attention has been paid to this enzyme. Hyaluronidase exists in various isoforms and generates a wide range of hyaluronic acid degradation products. This suggests that beyond its role as a spreading factor venom hyaluronidase deserves to be explored as a possible therapeutic target for inhibiting the systemic distribution of venom and also for minimizing local tissue destruction at the site of the bite. Copyright © 2005 John Wiley & Sons, Ltd. [source] Synthesis and Electrochemical Studies of Bingel,Hirsch Derivatives of M3N@Ih -C80 (M=Sc, Lu)CHEMISTRY - A EUROPEAN JOURNAL, Issue 16 2010Julio Abstract Bingel,Hirsch derivatives of the trimetallic nitride template endohedral metallofullerenes (TNT-EMFs) Sc3N@Ih -C80 and Lu3N@Ih -C80 were prepared by reacting these compounds with 2-bromodiethyl malonate, 2-bromo-1,3-dipyrrolidin-1-ylpropane-1,3-dionate bromide, and 9-bromo fluorene. The mono-adducts were isolated and their 1H,NMR spectra showed that the addition occurred with high regioselectivity at the [6,6] bonds of the Ih -C80 fullerene cage. Electrochemical analysis showed that the reductive electrochemistry behavior of these derivatives is irreversible at a scan rate of 100,mV,s,1, which is comparable to the behavior of the pristine fullerene species. The first reduction potential of each derivative is either cathodically or anodically shifted by a different value, depending on the attached addend. Bis-adducts containing EtOOC-C-COOEt and HC-COOEt addends were isolated by HPLC and in the case of Sc3N@Ih -C80 the first reduction potential exhibits a larger shift towards negative potentials when compared to the mono-adduct. This observation is important for designing acceptor materials for the construction of bulk heterojunction (BHJ) organic solar cells, since the polyfunctionalization not only increases the solubility of the fullerene species but also offers a promising approach for bringing the LUMO energy levels closer for the donor and the acceptor materials. [source] Changes in mean arterial pressure predict degranulation of renomedullary interstitial cellsCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 12 2002Christine Maric Summary 1.,Renomedullary interstitial cells (RMIC) are characterized by numerous intracellular granules thought to contain renal medullary antihypertensive substances. However, the nature of the trigger for RMIC degranulation remains to be elucidated. The present study examines the effects of acute alterations in mean arterial pressure (MAP) and medullary blood flow (MBF) on RMIC granulation. 2.,Basal MAP and MBF in anaesthetized Sprague-Dawley rats (n = 4/group) were altered by intravenous infusions of vasoactive agents, including angiotensin II alone or with a nitric oxide (NO) synthase inhibitor (N, -nitro- l -arginine) or NO donor (sodium nitroprusside), noradrenaline and by carotid artery clamping. Following these treatments, kidneys were examined by electron microscopy and the absolute volume of granules in the renal medulla was calculated using unbiased stereological methods. 3.,Acute increases in MAP, regardless of the treatment causing the increase, were associated with a reduction in the absolute volume of granules in the range of 42,67%. Regression analysis revealed that only increases in MAP, but not MBF, strongly predict RMIC degranulation. 4.,Despite previous reports that changes in MBF activate renomedullary antihypertensive activity, we conclude that the change in MAP is an important determinant of the activity of the blood pressure-lowering mechanism of the renal medulla, with the assumption that the medullary lipids mediate the antihypertensive property of the renal medulla. [source] | ||||||||||||||||||||||