706 research outputs found
Modelling the economic efficiency of using different strategies to control Porcine Reproductive & Respiratory Syndrome at herd level
PRRS is among the diseases with the highest economic impact in pig production worldwide. Different strategies have been developed and applied to combat PRRS at farm level. The broad variety of available intervention strategies makes it difficult to decide on the most cost-efficient strategy for a given farm situation, as it depends on many farm-individual factors like disease severity, prices or farm structure. Aim of this study was to create a simulation tool to estimate the cost-efficiency of different control strategies at individual farm level. Baseline is a model that estimates the costs of PRRS, based on changes in health and productivity, in a specific farm setting (e.g. farm type, herd size, type of batch farrowing).
The model evaluates different intervention scenarios: depopulation/repopulation (D/R), close & roll-over (C&R), mass vaccination of sows (MS), mass vaccination of sows and vaccination of piglets (MS + piglets), improvements in internal biosecurity (BSM), and combinations of vaccinations with BSM. Data on improvement in health and productivity parameters for each intervention were obtained through literature review and from expert opinions. The economic efficiency of the different strategies was assessed over 5 years through investment appraisals: the resulting expected value (EV) indicated the most cost-effective strategy. Calculations were performed for 5 example scenarios with varying farm type (farrow-to-finish – breeding herd), disease severity (slightly – moderately – severely affected) and PRRSV detection (yes – no). The assumed herd size was 1000 sows with farm and price structure as commonly found in Germany. In a moderately affected (moderate deviations in health and productivity parameters from what could be expected in an average negative herd), unstable farrow-to-finish herd, the most cost-efficient strategies according to their median EV were C&R (€1′126′807) and MS + piglets (€ 1′114′649). In a slightly affected farrow-to-finish herd, no virus detected, the highest median EV was for MS + piglets (€ 721′745) and MS (€ 664′111). Results indicate that the expected benefits of interventions and the most efficient strategy depend on the individual farm situation, e.g. disease severity. The model provides new insights regarding the cost-efficiency of various PRRSV intervention strategies at farm level. It is a valuable tool for farmers and veterinarians to estimate expected economic consequences of an intervention for a specific farm setting and thus enables a better informed decision
Estimation of corrosion resistance of curing mixtures based on coal-bearing rocks from Western Donbass
Purpose. Substantiation of possible use of coal-bearing rocks as a replacement for a part of the filler in the preparation of shotcrete for lining of mine workings in the conditions of mineralized mine water.
Methods. The research is based on carrying out corrosion testing of concrete specimens by dipping them into mine water. Chemical analysis of mine waters composition has been completed. A scanning microscope was used to study the state of concrete specimens microstructure.
Findings. A comparative analysis was conducted to evaluate of the cement rock resistance to mineralized water, depending on the composition of the starting components for the grouting and shotcrete mixtures is carried out. The change in the chemical composition of mine water after soaking concrete specimens in it is defined. Photographs of concrete specimens microstructure after soaking in ordinary and mineralized water for 6 and 8 months are shown.
Originality. Curing mixtures based on coal-bearing rocks from Western Donbass are mineralized water resistant and can act as a quality protection from aggressive water filtrationdue to the properties of rocks used as a filler.
Practical implications. The results can be used for the rational choice of the composition of the concrete mixture with the replacement of filler part with mine rock. That will enhance the long-term stability of the mine working lined by these compositions.Мета. Обґрунтування можливості використання вуглевміщуючих порід у якості заміни частини заповнювача в процесі приготування бетону для кріплення гірничих виробок в умовах мінералізованих шахтних вод.
Методика. Робота базується на проведенні корозійних випробувань бетонних зразків шляхом занурення їх у шахтну воду. Виконано хімічний аналіз складу шахтних вод. Використаний растровий мікроскоп для дослідження стану мікроструктури бетонних зразків.
Результати. Виконано порівняльний аналіз оцінки стійкості цементного каменю до впливу мінералізованої води залежно від складу вихідних компонентів для тампонажних, торкрет-бетонних і набризкбетонних сумішей. Визначено зміну хімічного складу шахтної води після витримки у ній бетонних зразків. Наведено фотографії мікроструктури бетонних зразків після витримки у нормальних умовах та мінералізованої води протягом 6 і 8 місяців.
Наукова новизна. Твердіючі суміші на основі вуглевміщуючих порід Західного Донбасу достатньо стійкі до впливу мінералізованих вод та є якісною протифільтраційною завісою завдяки властивостям порід, використаних у якості заповнювача.
Практична значимість. Отримані результати можуть бути використані для раціонального підбору складу бетонної суміші із заміною частини заповнювача шахтної породою, що дозволить підвищити тривалу стійкість гірничої виробки, закріпленої з використанням даних складів.Цель. Обоснование возможности использование углевмещающих пород в качестве замены части заполнителя в процессе приготовления бетона для крепления горных выработок в условиях минерализованных шахтных вод.
Методика. Работа базируется на проведении коррозионных испытаний бетонных образцов путем погружения их в шахтную воду. Выполнен химический анализ состава шахтных вод. Использован растровый микроскоп для исследования состояния микроструктуры бетонных образцов.
Результаты. Выполнен сравнительный анализ оценки устойчивости цементного камня к воздействию минерализованной воды в зависимости от состава исходных компонентов для тампонажных, торкрет-бетонных и набрызгбетонных смесей. Определено изменение химического состава шахтной воды после выдержки в ней бетонных образцов. Представлены фотографии микроструктуры бетонных образцов после выдержки в нормальных условиях и минерализованной воде в течение 6 и 8 месяцев.
Научная новизна. Твердеющие смеси на основе углевмещающих пород Западного Донбасса устойчивы к влиянию минерализованных вод и являются качественной противофильтрационной завесой благодаря свойствам пород, использованных в качестве заполнителя.
Практическая значимость. Полученные результаты могут быть использованы для рационального подбора состава бетонной смеси с заменой части заполнителя шахтной породой, что позволит повысить длительную устойчивость горной выработки, закрепленной с использованием данных составов.The authors express their gratitude to the administration of the Department of Construction, Geotechnics and Geomechanics of the National Mining University (Dnipropetrovsk, Ukraine), represented by O. Shashenko and A. Solodiankin, as well as to all those who helped in carrying out works related to preparation of this paper
Проблемы процесса управления в техносферной безопасности
В статье будет рассмотрены проблемы техносферной безопасности через интеграционный подход, как самый эффективный в сфере управления природопользования. Самые важные проблемы будут обобщены в вопросах государственного регулирования, также будут выявлены факторы влияния на эффективность управления данного процесса
Dimethylethanolamine Decreases Epileptiform Activity in Acute Human Hippocampal Slices in vitro
Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy with about 30% of patients developing pharmacoresistance. These patients continue to suffer from seizures despite polytherapy with antiepileptic drugs (AEDs) and have an increased risk for premature death, thus requiring further efforts for the development of new antiepileptic therapies. The molecule dimethylethanolamine (DMEA) has been tested as a potential treatment in various neurological diseases, albeit the functional mechanism of action was never fully understood. In this study, we investigated the effects of DMEA on neuronal activity in single-cell recordings of primary neuronal cultures. DMEA decreased the frequency of spontaneous synaptic events in a concentration-dependent manner with no apparent effect on resting membrane potential (RMP) or action potential (AP) threshold. We further tested whether DMEA can exert antiepileptic effects in human brain tissue ex vivo. We analyzed the effect of DMEA on epileptiform activity in the CA1 region of the resected hippocampus of TLE patients in vitro by recording extracellular field potentials in the pyramidal cell layer. Epileptiform burst activity in resected hippocampal tissue from TLE patients remained stable over several hours and was pharmacologically suppressed by lacosamide, demonstrating the applicability of our platform to test antiepileptic efficacy. Similar to lacosamide, DMEA also suppressed epileptiform activity in the majority of samples, albeit with variable interindividual effects. In conclusion, DMEA might present a new approach for treatment in pharmacoresistant TLE and further studies will be required to identify its exact mechanism of action and the involved molecular targets
Cost of porcine reproductive and respiratory syndrome virus at individual farm level – An economic disease model
Porcine reproductive and respiratory syndrome (PRRS) is reported to be among the diseases with the highest economic impact in modern pig production worldwide. Yet, the economic impact of the disease at farm level is not well understood as, especially in endemically infected pig herds, losses are often not obvious. It is therefore difficult for farmers and veterinarians to appraise whether control measures such as virus elimination or vaccination will be economically beneficial for their farm. Thus, aim of this study was to develop an epidemiological and economic model to determine the costs of PRRS for an individual pig farm. In a production model that simulates farm outputs, depending on farm type, farrowing rhythm or length of suckling period, an epidemiological model was integrated. In this, the impact of PRRS infection on health and productivity was estimated. Financial losses were calculated in a gross margin analysis and a partial budget analysis based on the changes in health and production parameters assumed for different PRRS disease severities. Data on the effects of endemic infection on reproductive performance, morbidity and mortality, daily weight gain, feed efficiency and treatment costs were obtained from literature and expert opinion. Nine different disease scenarios were calculated, in which a farrow-to-finish farm (1000 sows) was slightly, moderately or severely affected by PRRS, based on changes in health and production parameters, and either in breeding, in nursery and fattening or in all three stages together. Annual losses ranged from a median of € 75′724 (90% confidence interval (C.I.): € 78′885–€ 122′946), if the farm was slightly affected in nursery and fattening, to a median of € 650′090 (90% C.I. € 603′585–€ 698′379), if the farm was severely affected in all stages. Overall losses were slightly higher if breeding was affected than if nursery and fattening were affected. In a herd moderately affected in all stages, median losses in breeding were € 46′021 and € 422′387 in fattening, whereas costs were € 25′435 lower in nursery, compared with a PRRSV-negative farm. The model is a valuable decision-support tool for farmers and veterinarians if a farm is proven to be affected by PRRS (confirmed by laboratory diagnosis). The output can help to understand the need for interventions in case of significant impact on the profitability of their enterprise. The model can support veterinarians in their communication to farmers in cases where costly disease control measures are justified
Acute symptomatic seizures in the emergency room: predictors and characteristics
Background: When treating patients with epileptic seizures in the emergency room (ER), it is of paramount importance to rapidly assess whether the seizure was acute symptomatic or unprovoked as the former points to a potentially life-threatening underlying condition. In this study, we seek to identify predictors and analyze characteristics of acute symptomatic seizures (ASS).
Methods: Data from patients presenting with seizures to highly frequented ERs of two sites of a university hospital were analyzed retrospectively. Seizures were classified as acute symptomatic or unprovoked according to definitions of the International League Against Epilepsy. Univariate and multivariate analysis were conducted to identify predictors; furthermore, characteristics of ASS were assessed.
Results: Finally, 695 patients were included, 24.5% presented with ASS. Variables independently associated with ASS comprised male sex (OR 3.173, 95% CI 1.972-5.104), no prior diagnosis of epilepsy (OR 11.235, 95% CI 7.195-17.537), and bilateral/generalized tonic-clonic seizure semiology (OR 2.982, 95% CI 1.172-7.588). Alcohol withdrawal was the most common cause of ASS (74.1%), with hemorrhagic stroke being the second most prevalent etiology. Neuroimaging was performed more often in patients with the final diagnosis of ASS than in those with unprovoked seizures (82.9% vs. 67.2%, p < 0.001). Patients with ASS were more likely to receive acute antiseizure medication in the ER (55.9% vs. 30.3%, p < 0.001).
Conclusions: In one quarter of patients presenting to the ER after an epileptic fit, the seizure had an acute symptomatic genesis. The independently associated variables may help to early identify ASS and initiate management of the underlying condition
Explanation for Anomalous Shock Temperatures Measured by Neutron Resonance Spectroscopy
Neutron resonance spectrometry (NRS) has been used to measure the temperature
inside Mo samples during shock loading. The temperatures obtained were
significantly higher than predicted assuming ideal hydrodynamic loading. The
effect of plastic flow and non-ideal projectile behavior were assessed. Plastic
flow was calculated self-consistently with the shock jump conditions: this is
necessary for a rigorous estimate of the locus of shock states accessible.
Plastic flow was estimated to contribute a temperature rise of 53K compared
with hydrodynamic flow. Simulations were performed of the operation of the
explosively-driven projectile system used to induce the shock in the Mo sample.
The simulations predicted that the projectile was significantly curved on
impact, and still accelerating. The resulting spatial variations in load,
including radial components of velocity, were predicted to increase the
apparent temperature that would be deduced from the width of the neutron
resonance by 160K. These corrections are sufficient to reconcile the apparent
temperatures deduced using NRS with the accepted properties of Mo, in
particular its equation of state.Comment: near-final version, waiting for final consent from an autho
Complex Faulting and Triggered Rupture During the 2018 MW 7.9 Offshore Kodiak, Alaska, Earthquake
We combine aftershock relocations, source mechanisms, teleseismic P wave backprojection, and Global Positioning System data inversion to constrain complex faulting geometry of the 2018 MW 7.9 offshore Kodiak earthquake. Relocated aftershocks delineate several N‐S trends including a prominent 110‐km‐long segment, as well as broad NE‐SW trends. Global Positioning System modeling and backprojection indicate that the NE‐SW trending left‐lateral strike‐slip segments released most energy dominating far‐field crustal deformation and radiated wavefield. Backprojection infers fast E‐to‐W rupture propagations superimposed on a slower S‐to‐N migration. We propose a five‐segment model of the rupture that was partially driven by dynamic triggering
Shock and Release Temperatures in Molybdenum
Shock and release temperatures in Mo were calculated, taking account of
heating from plastic flow predicted using the Steinberg-Guinan model. Plastic
flow was calculated self-consistently with the shock jump conditions: this is
necessary for a rigorous estimate of the locus of shock states accessible. The
temperatures obtained were significantly higher than predicted assuming ideal
hydrodynamic loading. The temperatures were compared with surface emission
spectrometry measurements for Mo shocked to around 60GPa and then released into
vacuum or into a LiF window. Shock loading was induced by the impact of a
planar projectile, accelerated by high explosive or in a gas gun. Surface
velocimetry showed an elastic wave at the start of release from the shocked
state; the amplitude of the elastic wave matched the prediction to around 10%,
indicating that the predicted flow stress in the shocked state was reasonable.
The measured temperatures were consistent with the simulations, indicating that
the fraction of plastic work converted to heat was in the range 70-100% for
these loading conditions
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