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Sudden Increase (sudden + increase)
Selected AbstractsThe Measurement of Daily Surge and Its Relevance to Disaster PreparednessACADEMIC EMERGENCY MEDICINE, Issue 11 2006Melissa L. McCarthy MS This article reviews what is known about daily emergency department (ED) surge and ED surge capacity and illustrates its potential relevance during a catastrophic event. Daily ED surge is a sudden increase in the demand for ED services. There is no well-accepted, objective measure of daily ED surge. The authors propose that daily and catastrophic ED surge can be measured by the magnitude of the surge, as well as by the nature and severity of the illnesses and injuries that patients present with during the surge. The magnitude of an ED surge can be measured by the patient arrival rate per hour. The nature and severity of the surge can be measured by the type (e.g., trauma vs. infection vs. biohazard) and acuity (e.g., triage level) of the surge. Surge capacity is defined as the extent to which a system can respond to a rapid and sizeable increase in the demand for resources. ED surge capacity includes multiple dimensions, such as systems, space, staffing, and supplies. A multidimensional measure is needed that reflects both the core components and their relative contribution to ED surge capacity. Although many types of factors may influence ED surge capacity, relatively little formal research has been conducted in this area. A better understanding of daily ED surge capacity and influencing factors will improve our ability to simulate the potential impact that different types of catastrophic events may have on the surge capacity of hospital EDs nationwide. [source] Sturge,Weber syndrome and paroxysmal hemiparesis: epilepsy or ischaemia?DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 11 2004Floor E Jansen MD Transient neurological deficits experienced by patients with Sturge,Weber syndrome can be caused by epilepsy, or may result from temporary ischaemia of the cortex underlying the vascular malformation. To show the difficulty in distinguishing seizures from ischaemic symptoms, two male children with episodes of acute unilateral weakness are presented here as well as a review of the literature. The first child presented at 2 years of age with a sudden increase in his pre-existing right hemiparesis accompanied by screaming. Ictal epileptiform activity was recorded at the moment of the attack, and subsequent seizures were controlled by adjustment of antiepileptic drug treatment. The second child presented at 4 years of age with attacks of vomiting and a coinciding increase in the pre-existing paresis of the left leg. Electroencephalogram (EEG) recording did not show ictal epileptiform activity. The origin was presumed to be vascular. Treatment with aspirin led to control of these transient ischaemic attacks. Ictal EEG is needed to differentiate between an epileptic and an ischaemic origin of transient focal deficit. Treatment with aspirin should be considered if an ischaemic origin cannot be excluded. [source] ORIGINAL INVESTIGATIONS: Potential Faces of Patent Foramen Ovale (PFO PFO)ECHOCARDIOGRAPHY, Issue 8 2010F.R.C.P., Tasneem Z Naqvi M.D. Background: Patent foramen ovale (PFO) is diagnosed on echocardiography by saline contrast study with or without color Doppler evidence of shunting. PFO is benign except when it causes embolic events. Methods and Results: In this report, we describe unique additional manifestations related to the diagnosis and presentation of PFO. These include demonstration of PFO during the release phase of "sigh" on the ventilator in the operating room, use of a separate venipuncture to allow preparation of blood-saline-air mixture after multiple failed saline bubble injections, resting and stress hypoxemia related to left to right shunting across a PFO in the absence of pulmonary hypertension, presentation of quadriperesis secondary to an embolic event from a PFO and development of a thrombus on the left atrial aspect of PFO in a patient with atrial fibrillation, and on the right atrial aspect of PFO in a patient who had undergone repair of a flail mitral valve. Finally, in one patient with end-stage renal disease, aortic valve endocarditis and periaortic abscess, PFO acted as a vent valve relieving right atrial pressure following development of aortoatrial fistula. Conclusion: PFO diagnosis can be elusive if appropriate techniques are not used during saline contrast administration. PFO can present as hypoxemia in the absence of pulmonary hypertension, can be a rare cause of quadriperesis, and can be associated with thrombus formation on either side of interatrial septum. Finally, PFO presence can be lifesaving in those with sudden increase in right atrial pressure such as with aortoatrial fistula. (Echocardiography 2010;27:897-907) [source] Nocturnal migration of dragonflies over the Bohai Sea in northern ChinaECOLOGICAL ENTOMOLOGY, Issue 5 2006HONG-QIANG FENG Abstract 1.,A sudden increase and subsequent sharp decrease of catches of dragonflies in a searchlight trap, with Pantala flavescens Fabricius (Odonata: Libellulidae) predominating, observed at Beihuang Island in the centre of the Bohai Gulf, in 2003 and 2004, indicated a seasonal migration of these insects over the sea during the night in China. The movements were associated with the onset of fog. 2.,Simultaneous radar observations indicated that the nocturnally migrating dragonflies generally flew at altitudes of up to 1000 m above sea level, with high density concentrations at about 200,300 or 500 m; these concentrations were coincident with the temperature inversion. 3.,During early summer, the dragonflies oriented in a downwind direction, so that the displacement direction varied between different altitudes. In contrast, during late summer, the dragonflies were able to compensate for wind drift, even headwind drift, so as to orient south-westward no matter how the wind changed, and thus the displacement direction was towards the south-west. 4.,The duration of flight, estimated from the variation of area density derived from radar data and hourly catches in the searchlight trap through the night, was about 9,10 h. The displacement speed detected using radar was ,5,11 m s,1. Therefore, the dragonflies might migrate 150,400 km in a single flight. 5.,The dragonflies were thought to originate in Jiangsu province and they migrated into north-east China to exploit the temporary environment of paddy fields in early summer. Their offspring probably migrated back south during late summer and autumn. [source] Effect of temperature and moisture on rates of carbon mineralization in a Mediterranean oak forest soil under controlled and field conditionsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 5 2005A. Rey Summary We examined the relationship between carbon mineralization (Cmin), moisture and temperature in a Mediterranean forest soil under controlled and field conditions. We studied the following. 1,The temperature sensitivity at three soil depths: soil samples were incubated at 4, 10, 20 and 30°C at optimal water content of 60% of water holding capacity (WHC). Values of Cmin of the top layer were more than 12 times faster than those measured in deeper layers. We found a temperature sensitivity factor (Q10) of 3.3, 2.7 and 2.2 for the 0,5 cm, 5,10 cm and 10,20 cm layers, respectively. 2,The relationship between Cmin, moisture and temperature (top layer). The sensitivity of Cmin to fluctuating moisture depended on temperature. However, the Q10 was not significantly affected by soil moisture. We fitted a multiple polynomial model that predicted Cmin as a multiplicative function of temperature and moisture (R2 > 0.99). 3,The response of Cmin of soil to rewetting after 1 and 24 hours. In all cases, the response was rapid. The soil incubated at 60% WHC or less responded positively to a sudden increase in water content, with the largest increase in the 20% WHC treatment. The model predicted Cmin in the field well when rewetting effects were taken into account (R2 > 0.81). These results indicate that sudden changes in soil moisture can lead to increased carbon mineralization during the dry summer. It is necessary to include such responses in models as they may represent a substantial loss of carbon in the overall carbon balance of Mediterranean ecosystems. [source] Comparison of the modified three-rail shear test and the [(+45°,,45°)]ns tensile test for pure shear fatigue loading of carbon fabric thermoplasticsFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 6 2008I. DE BAERE ABSTRACT The (three)-rail shear test is rarely considered for testing of fibre-reinforced composites under pure shear fatigue loading conditions because of all experimental difficulties. However, in this article, a carbon fabric-reinforced PPS is tested using a modified three-rail shear test setup. The results are compared with [(+45°,,45°)]4s tensile tests with good correspondence. All fatigue experiments were done with R= 0 and the influence of maximum shear stress and frequency is investigated. It can be concluded that an increase in maximum shear stress decreases fatigue lifetime, whereas an increase in frequency increases the lifetime. Before failure, a sudden increase in both temperature and permanent deformation could be detected. Creep tests yielded that the occurring deformation is mainly due to the fatigue loading, rather than due to creep phenomena. [source] Role of reserve carbohydrates in the growth dynamics of Saccharomyces cerevisiae,FEMS YEAST RESEARCH, Issue 8 2004Vincent Guillou Abstract The purpose of this study was to explore the role of glycogen and trehalose in the ability of Saccharomyces cerevisiae to respond to a sudden rise of the carbon flux. To this end, aerobic glucose-limited continuous cultures were challenged with a sudden increase of the dilution rate from 0.05 to 0.15 h,1. Under this condition, a rapid mobilization of glycogen and trehalose was observed which coincided with a transient burst of budding and a decrease of cell biomass. Experiments carried out with mutants defective in storage carbohydrates indicated a predominant role of glycogen in the adaptation to this perturbation. However, the real importance of trehalose in this response was veiled by the unexpected phenotypes harboured by the tps1 mutant, chosen for its inability to synthesize trehalose. First, the biomass yield of this mutant was 25% lower than that of the isogenic wild-type strain at dilution rate of 0.05 h,1, and this difference was annulled when cultures were run at a higher dilution rate of 0.15 h,1. Second, the tps1 mutant was more effective to sustain the dilution rate shift-up, apparently because it had a faster glycolytic rate and an apparent higher capacity to consume glucose with oxidative phosphorylation than the wild type. Consequently, a tps1gsy1gsy2 mutant was able to adapt to the dilution rate shift-up after a long delay, likely because the detrimental effects from the absence of glycogen was compensated for by the tps1 mutation. Third, a glg1,glg2, strain, defective in glycogen synthesis because of the lack of the glycogen initiation protein, recovered glycogen accumulation upon further deletion of TPS1. This recovery, however, required glycogen synthase. Finally, we demonstrated that the rapid breakdown of reserve carbohydrates triggered by the shift-up is merely due to changes in the concentrations of hexose-6-phosphate and UDPglucose, which are the main metabolic effectors of the rate-limiting enzymes of glycogen and trehalose pathways. [source] Experimental study on water spray suppression on burning upholstered chair in an enclosure with different application timesFIRE AND MATERIALS, Issue 5 2009Q. Y. Xie Abstract The objective of this work is to investigate the effects of the application time of water spray on the burning upholstered chair in an enclosure. A series of experiments are conducted with the same water flow rate in an ISO 9705 fire test room in which a water spray system is installed. Several identical upholstered chairs are used in the experiments with the application times 20, 25, 30, 40 and 45,s after the ignition of upholstered chair, respectively. The results show that there is nearly an exponential relationship between the peak heat release rates and the relative application times of water spray. It is also shown that there is a polynomial relationship between the relative time for the peak heat release rate and the relative application time of water spray. However, there is an exponential relationship between the whole relative extinguishing time and the relative application time of water spray. A sudden increase is detected before the decreasing of CO generation rates after the water spray is applied on the burning upholstered chair. The average temperatures of the upper hot smoke layer under the ceiling will generally be lower with the earlier application of water spray. Copyright © 2009 John Wiley & Sons, Ltd. [source] Palynological evidence for late Holocene environmental change on the Gimhae fluvial plain, Southern Korean peninsula: Reconstructing the rise and fall of Golden Crown Gaya StateGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 8 2003Sangheon Yi This paper presents the results of detailed studies of palynomorphs recovered from two cores collected near the Yeanri burial mound on the Gimhae fluvial plain. Two local pollen zones were recognized on the basis of variations in the palynofloral assemblage: a lower Pollen Zone I, dominated by a Pinus-Quercus assemblage, and an upper Pollen Zone II, dominated by a Pinus-Quercus -Gramineae assemblage. The palynological and molluscan analyses indicate that the depositional environments changed from a lower intertidal flat of a shallow bay environment to an upper intertidal flat in a shallow bay (before 1280 ± 110 14C yr B.P.), and finally to a fluvial plain similar to that of today. This environmental change may have resulted from uplift along the Yangsan Fault. Afterward, the exposed area was modified by human activities, as indicated by a sudden increase in grassland herbaceous pollen grains. The loss of this bay likely had a dramatic effect on the Golden Crown Gaya State (3rd,7th centuries A.D.), which used it as a major port for regional trade, and may explain why it eventually merged with the Shilla State. © 2003 Wiley Periodicals, Inc. [source] A thermal nonlinear dynamic model for water tube drum boilersINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 1 2010M. A. Habib Abstract A thermal model for the prediction of possible tube overheating was developed. The model incorporates a nonlinear state space dynamic model that captures the important physical interactions of the main variables of steam generation in naturally circulated water tube drum boilers. This paper provides an investigation of the dynamic effects of rapid rise in fuel flow rate (heat input) on the thermal and flow characteristics of the riser tubes in natural circulation water tube boilers. The system under consideration includes the drum, riser and downcomer as its major components. The dynamic response of the system's state variables due to rapid rises in fuel flow rates was investigated. The results show that the sudden rise in the firing rate is followed by an increase in the steam quality, which is accompanied by a decrease in the circulation rate as a result of increase in the pressure. The riser temperature increases slightly above the saturation temperature due to the increase in the steam temperature and due to the dynamic influence resulting from sudden increase in the heat flux. The present calculations of the water level in the drum provide good comparison with those in the literature. Copyright © 2009 John Wiley & Sons, Ltd. [source] Dynamic peroxide method for kLaO2 estimationJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2009Marcos Marcelino Abstract BACKGROUND: A reliable kLaO2 estimation methodology in bioreactors is a recurrent topic in the literature owing to the significance of this value, particularly in respirometric measurements. The most common methodologies for kLaO2 estimation consist of modeling the profile of dissolved oxygen (DO) obtained after a perturbation of the system aeration. Among them, the dynamic peroxide method (DPM), which consists of a small addition of peroxide hydrogen for a sudden increase in the DO level, is a promising methodology. RESULTS: This work studies the reliability of kLaO2 estimates using DPM. Different experiments were performed with sludge cultures enriched with heterotrophs, nitrifiers and polyphosphate accumulating organisms (PAO). The influence of several operational conditions (i.e. air flow, sludge concentration, H2O2 volume addition) on kLaO2 estimates was studied and the reliability of DPM was compared with the widely used reaeration methodology. An application of DPM in the assessment of oxygen surface transfer in a mechanically stirred bioreactor is described. CONCLUSION: DPM is a reliable methodology for kLaO2 estimation that can be successfully applied to heterotrophs, nitrifiers and PAO without observing any inhibitory effect ([H2O2] , 6 mg L,1). Copyright © 2009 Society of Chemical Industry [source] Heat Transfer in Gas Phase Olefin PolymerisationMACROMOLECULAR SYMPOSIA, Issue 1 2009Estevan Tioni Abstract A fixed bed microreactor has been used to study heat transfer during the initial transient state of gas phase olefin polymerization on a supported catalyst. It has been shown that heat transfer during this stage of the polymerisation is critical, and under conditions found commercially problems can arise with hot spots and polymer melting. It is proven how the thermal properties of the gas mixture flowing on the catalytic bed exert great influence on heat dissipation reducing the sudden increase in temperature by as much as a factor of 5. Flow rate and especially the process gas composition are the key factors in controlling the bed temperature. [source] The cellular level of the recognition factor RssB is rate-limiting for ,S proteolysis: implications for RssB regulation and signal transduction in ,S turnover in Escherichia coliMOLECULAR MICROBIOLOGY, Issue 6 2002Mihaela Pruteanu Summary Degradation of the general stress sigma factor ,S of Escherichia coli is a prime example of regulated proteolysis in prokaryotes. Whereas exponentially growing cells rapidly degrade ,S, various stress conditions result in stabilization and, therefore, rapid accumulation of ,S. Proteolysis of ,S requires the response regulator RssB, a direct recognition factor with phosphorylation-dependent affinity for ,S, which targets ,S to the ClpXP protease. Here, we demonstrate that a sudden increase in ,S synthesis results in ,S stabilization, indicating titration of an essential proteolytic component. Evidence is provided that RssB is the overall rate-limiting factor for ,S proteolysis. As a consequence, the cell has to continuously adjust the expression of RssB to ,S in order to maintain ,S proteolysis in growing cells, despite variations in the rate of ,S synthesis. Such homeostatic feedback-coupling is provided by rssB transcription being dependent on the ,S -controlled rssAB operon promoter. However, strong and rapid increases in ,S synthesis, in re-sponse to acute stress, exceed the compensatory potential of this feedback loop with the result that ,S is stabilized because of RssB titration. We propose that RssB control of ,S proteolysis functions as a genetic switch, in which (i) the ,off' state (low ,S levels caused by proteolysis) is stabilized by a homeostatic negative feedback, and (ii) the threshold for switching to the ,on' state (high levels of stable ,S) is dependent on the cellular level of active, i.e. phosphorylated RssB. [source] Positron annihilation studies in plastically deformed Fe-Mn-Si-Cr-Ni-CPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 10 2007J. De Baerdemaeker Abstract Fe-Mn-Si-Cr-Ni-C samples with deformations from 2 to 20% were investigated using positron annihilation spectroscopy, optical microscopy (OM) and X-ray diffraction (XRD). Both Doppler broadening of the annihilation radiation (DBAR) and positron annihilation lifetime spectroscopy (PALS) measurements were performed. The DBAR experiments, carried out using a slow positron beam, indicate a sudden increase in the defect concentration in between 4 and 6% deformation. This is confirmed by the lifetime measurements. In between 6% and 8% deformation the lineshape parameter significantly changes which coincides with the drastic increase of the concentration of the martensite phase as confirmed by XRD. Positron annihilation spectroscopy indirectly probe the ,/, martensitic phase transformation by probing correlated dislocations. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The familial hypertrophic cardiomyopathy-associated myosin mutation R403Q accelerates tension generation and relaxation of human cardiac myofibrilsTHE JOURNAL OF PHYSIOLOGY, Issue 15 2008Alexandra Belus The R403Q mutation in ,-myosin heavy chain was the first mutation to be identified as responsible for familial hypertrophic cardiomyopathy (FHC). In spite of extensive work on the functional sequelae of this mutation, the mechanism by which the mutant protein causes the disease has not been definitely identified. Here we directly compare contraction and relaxation mechanics of single myofibrils from left ventricular samples of one patient carrying the R403Q mutation to those from a healthy control heart. Tension generation and relaxation following sudden increase and decrease in [Ca2+] were much faster in the R403Q myofibrils with relaxation rates being the most affected parameters. The results show that the R403Q mutation leads to an apparent gain of protein function but a greater energetic cost of tension generation. Increased energy cost of tension generation may be central to the FHC disease process, help explain some unresolved clinical observations, and carry significant therapeutic implications. [source] Use of povidone,iodine during the first trimester of pregnancy: a correct practice?BJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 3 2009I Velasco Povidone,iodine (PVP-I) has been widely used as an antiseptic agent during invasive procedures for prenatal diagnosis. Women have been reported of thyroid dysfunction after simple exposure to PVP-I. We studied the effect on thyroid function and urinary iodine excretion after a single topical application of PVP-I in 31 women who had a miscarriage during the first trimester of pregnancy. PVP-I is absorbed through the skin and the vaginal mucosa, resulting in a sudden increase in the urinary excretion of iodine and a short-term variation in concentrations of thyroid hormones in maternal serum. This metabolic effect could have consequences for the embryo and the fetus during crucial stages of development. [source] Patient-adjusted intermittent electrostimulation for treating stress and urge urinary incontinenceBJU INTERNATIONAL, Issue 1 2004Israel Nissenkorn OBJECTIVE To assess the safety and efficacy of pelvic floor muscle electrostimulation (ES) in women with stress urinary incontinence (SUI) or mixed UI (MUI, urge and interstitial cystitis), using a new portable electrostimulator (Miniaturo, Biocontrol Medical Inc., Yehud, Israel) which delivers different forms of stimulation for treating these two conditions. PATIENTS AND METHODS For SUI the stimulator is activated on demand only by a sudden increase in intra-abdominal pressure; for frequency and urgency a milder, continuous ES is used. The intensity of ES can be adjusted according to the patient's sensation. Women were enrolled into the study after satisfying inclusion criteria and pad testing; 23 participated in two study groups, i.e. 16 with SUI and seven with MUI (severe frequency, urgency and urge, and mild SUI). The pelvic floor muscles were stimulated through an electrode inserted paraurethrally, positioned similarly in all patients. In patients with SUI and MUI a pressure sensor was also inserted into the rectum, to record intra-abdominal pressure. Stimulation was applied for 1,4 h in patients with SUI and for 6 h in those with MUI. The evaluation was based on urinary symptoms (frequency, urgency, leaking episodes), quality-of-life questionnaires and pad tests at baseline and during stimulation. RESULTS All patients in both groups improved significantly; of the 16 patients with SUI, nine were completely dry during ES, and the remaining seven had a reduced mean pad weight, from 23 to 6 g (74%). There was no significant reduction in pad weight after sham ES (17 g before vs 24.2 g after). In four patients with SUI who continued ES for 4 h the mean cumulative stimulation time (calculated from the stimulator memory) was 3 min (1.3% of 4 h). In the MUI group there were no leakage episodes during ES and significant reductions in voiding variables (Student's t -test) in all. The mean (Sd) voiding frequency, urinary urgency and leaking episodes decreased from 8.1 (4.2) to 1.9 (1.5), 6.4 (2.3) to 0.7 (1.3) and 2.1 (0.7) to 0.7 (0.5) (all P < 0.001), respectively. CONCLUSIONS The concept of this ES system for treating UI is promising; this study supports the efficacy of this form of ES but no conclusions about clinical efficacy are possible at this stage, and thus a trial to evaluate the safety and efficacy of this implantable device is ongoing. [source] Acute left ventricular failure after large volume pericardiocentesisCLINICAL CARDIOLOGY, Issue 12 2003A. Chamoun M.D. Abstract This paper reports on two cases of large volume pericardiocentesis followed by transient severe acute left ventricular (LV) systolic failure in the absence of any prior history of LV dysfunction. Acute LV volume overload due to inter-ventricular volume mismatch is believed by most authors to be the cause for this phenomenon. Another plausible physiopathologic explanation is the acute increase in "wall stress" (Laplace's law) due to acute distention of the cardiac chambers secondary to a sudden increase in venous return at high filling pressures, combined with a "vacuum" effect of the evacuated pericardial space. [source] Cardiac sympathetic nerve activity during kainic acid,induced limbic cortical seizures in ratsEPILEPSIA, Issue 4 2009Harumi Hotta Summary We sought to define changes in cardiac sympathetic nerve activity that occur during seizures. We studied kainic acid,induced limbic cortical seizures in urethane-anesthetized rats using cardiac sympathetic nerve, blood pressure, and electrocardiography (ECG) recordings. We studied changes in ventilation rate before and during seizures. Cardiac sympathetic nerve activity was increased during limbic cortical seizures. The modest increases were similar to changes induced by nitroprusside infusion. The normal relation of cardiac sympathetic nerve activity to ventilation rate was lost during seizure activity. Changes in cardiac sympathetic nerve activity caused by changes in ventilation rate became unpredictable, and could be extreme. We conclude that the modest changes in cardiac sympathetic nerve activity contribute to the predominantly parasympathetic effects on the heart during limbic cortical seizures and periods of asphyxia. Further, ventilation rate changes might be associated with large sudden increases or decreases in cardiac sympathetic outflow during seizures. [source] Risk factors for epiploic foramen entrapment colic in a UK horse population: A prospective case-control studyEQUINE VETERINARY JOURNAL, Issue 4 2008D. C. ARCHER Summary Reasons for performing study: Epiploic foramen entrapment (EFE) is a common cause of small intestinal strangulation in the horse and its epidemiology requires further investigation. Objectives: To identify horse- and management-level risk factors for EFE and to explore reasons for the apparent seasonality of this condition. Hypothesis: Horses exhibiting certain behaviours and those exposed to particular management practices that vary seasonally are at increased risk of EFE. Methods: A prospective unmatched, multicentre case-control study was conducted over 24 months in the UK. Data on 77 cases and 216 control horses were obtained from 9 collaborating clinics and logistic regression was used to identify associations between horse and management variables and the likelihood of EFE. Results: In a final multivariable model crib-biting/ windsucking behaviour was associated with the largest increase in likelihood of EFE. A history of colic in the previous 12 months, increased stabling in the previous 28 days and height of the horse also increased the likelihood of EFE. Horses with access to a mineral/salt lick, those easily frightened and horses not fed at the same time as others were at reduced risk of EFE. Conclusions: Horses exhibiting certain behaviours, those with a previous history of colic and horses of greater height appear to be at inherently greater risk of EFE. The increase in likelihood of EFE with increased duration of stabling may explain the apparent seasonality of this condition. Potential relevance: These findings assist identification of horses at high-risk of EFE and provide information on management strategies that may reduce this risk. If the observed associations are causal, avoiding sudden increases in duration of stabling, not feeding horses in the same group at the same time and providing a mineral/salt lick may reduce the likelihood of EFE. The risk factors identified in this study provide important clues to the aetiology of EFE. [source] Performance of TCP on low-bandwidth wireless links with delay spikesEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 6 2008Pasi Lassila We model the goodput of a single TCP source on a wireless link experiencing sudden increases in Round Trip Time (RTT), that is delay spikes. Such spikes trigger spurious timeouts that reduce the TCP goodput. Renewal reward theory is used to derive a straightforward expression for TCP goodput that takes into account limited sending rates (limited window size), lost packets due to congestion and the delay spike properties such as the average spike duration and distribution of the spike intervals. The basic model is for independent and identically distributed (i.i.d.) spike intervals, and correlated spike intervals are modelled by using a modulating background Markov chain. Validation by ns2 simulations shows excellent agreement for lossless scenarios and good accuracy for moderate loss scenarios (for packet loss probabilities less than 5%). Numerical studies have also been performed to assess the impact of different spike interval distributions on TCP performance. Copyright © 2007 John Wiley & Sons, Ltd. [source] EVIDENCE THAT GREATER DISCLOSURE LOWERS THE COST OF EQUITY CAPITALJOURNAL OF APPLIED CORPORATE FINANCE, Issue 4 2000Christine A. Botosan The effect of corporate disclosure on the cost of equity capital is a matter of considerable interest and importance to both corporations and the investment community. However, the relationship between disclosure level and cost of capital is not well established and has proved difficult for researchers to quantify. As described in this article, the author's 1997 study (published in The Accounting Review) was the first to measure and detect a direct relationship between disclosure and cost of capital. After examining the annual reports of 122 manufacturing companies, the author concluded that companies providing more extensive disclosure had a lower (forward-looking) cost of equity capital (measured using Value Line forecasts with an EBO valuation formula that derives from the dividend discount model). For companies with extensive analyst coverage, differences in disclosure do not appear to affect cost of capital. But for companies with small analyst followings, differences in disclosure do appear to matter. Among this group of companies, the firms judged to have the highest level of disclosure had a cost of equity capital that was nine-percentage points lower than otherwise similar firms with a minimal level of disclosure. Closer analysis of some of the specific disclosure practices also suggests that, for small firms with limited analyst coverage, there are benefits to providing more forward-looking information, such as forecasts of sales, profits, and capital expenditures, and enhanced disclosure of key non-financial statistics, such as order backlogs, market share, and growth in units sold. In closing, the article also discusses an interesting new study (by Lang and Lundholm) that suggests there is an important distinction between effective corporate disclosure and "hyping the stock." The findings of this study show that while higher levels of disclosures are associated with higher stock prices, sudden increases in the frequency of disclosure are viewed with skepticism. [source] Physiological Responses of Acropora cervicornis to Increased Solar Irradiance,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2007Juan L. Torres ABSTRACT The effects of increased UV radiation (UV-B [280,320 nm] + UV-A [320,400 nm]; hereafter UVR) on the growth, production of photosynthetic pigments and photoprotective mycosporine-like amino acids (MAAs) were studied in the threatened Caribbean coral Acropora cervicornis transplanted from 20 to 1 m depth in La Parguera, Puerto Rico. The UVR exposure by the transplanted colonies was significantly higher than that at 20 m, while photosynthetically active radiation (PAR) only increased by 9%. Photosynthetic pigments, quantified with HPLC, as well as linear extension rates and skeletal densities, were significantly reduced 1 month after transplantation to 1 m depth, while MAAs increased significantly despite immediate paling experienced by transplanted colonies. While these colonies showed a significant reduction in photosynthetic pigments, there were no significant reductions in zooxanthellae densities suggesting photoacclimation of the coral's symbionts to the new radiation conditions. The results suggest that while corals might be able to survive sudden increases in UVR and PAR, their skeletal structure can be greatly debilitated due to a reduction in the photosynthetic capacity of their symbionts and a possible relocation of resources. [source] | ||||||||||||||||||||||||||||||||||