205 research outputs found
Bidding at Sequential First-Price Auctions with(out) Supply Uncertainty: A Laboratory Analysis
We report on a series of experiments that test the effects of an uncertain supply on the formation of bids and prices in sequential first-price auctions with private-independent values and unit-demands. Supply is assumed uncertain when buyers do not know the exact number of units to be sold (i.e., the length of the sequence). Although we observe a non-monotone behavior when supply is certain and an important overbidding, the data qualitatively support our price trend predictions and the risk neutral Nash equilibrium model of bidding for the last stage of a sequence, whether supply is certain or not. Our study shows that behavior in these markets changes significantly with the presence of an uncertain supply, and that it can be explained by assuming that bidders formulate pessimistic beliefs about the occurrence of another stage.Financial support from the University of Valencia (project GV98_08/2960) and from a EU-TMR ENDEAR Network Grant (FMRX-CT98-0238) is gratefully acknowledged
Bioguided isolation of alternariol derivatives from <i>Ficus</i>-derived endophyte <i>Alternaria alternata</i>
Системный подход к управлению экономикой знаний
Описываются особенности и уровни управления экономикой знаний. Через системный подход в современном менеджменте рассматривается организационное и ресурсное управление экономикой знаний. Обосновывается взаимообусловленность развития современного менеджмента и экономики знаний. Менеджмент постмодерна является драйвером для совершенствования стратегической концепции экономики знаний, и последняя, в свою очередь, вносит коррективы в траекторию динамики методологии современного менеджмента
Translational molecular imaging and drug development in Parkinson's disease
Parkinson's disease (PD) is a progressive neurodegenerative disorder that primarily affects elderly people and constitutes a major source of disability worldwide. Notably, the neuropathological hallmarks of PD include nigrostriatal loss and the formation of intracellular inclusion bodies containing misfolded α-synuclein protein aggregates. Cardinal motor symptoms, which include tremor, rigidity and bradykinesia, can effectively be managed with dopaminergic therapy for years following symptom onset. Nonetheless, patients ultimately develop symptoms that no longer fully respond to dopaminergic treatment. Attempts to discover disease-modifying agents have increasingly been supported by translational molecular imaging concepts, targeting the most prominent pathological hallmark of PD, α-synuclein accumulation, as well as other molecular pathways that contribute to the pathophysiology of PD. Indeed, molecular imaging modalities such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT) can be leveraged to study parkinsonism not only in animal models but also in living patients. For instance, mitochondrial dysfunction can be assessed with probes that target the mitochondrial complex I (MC-I), while nigrostriatal degeneration is typically evaluated with probes designed to non-invasively quantify dopaminergic nerve loss. In addition to dopaminergic imaging, serotonin transporter and N-methyl-D-aspartate (NMDA) receptor probes are increasingly used as research tools to better understand the complexity of neurotransmitter dysregulation in PD. Non-invasive quantification of neuroinflammatory processes is mainly conducted by targeting the translocator protein 18 kDa (TSPO) on activated microglia using established imaging agents. Despite the overwhelming involvement of the brain and brainstem, the pathophysiology of PD is not restricted to the central nervous system (CNS). In fact, PD also affects various peripheral organs such as the heart and gastrointestinal tract - primarily via autonomic dysfunction. As such, research into peripheral biomarkers has taken advantage of cardiac autonomic denervation in PD, allowing the differential diagnosis between PD and multiple system atrophy with probes that visualize sympathetic nerve terminals in the myocardium. Further, α-synuclein has recently gained attention as a potential peripheral biomarker in PD. This review discusses breakthrough discoveries that have led to the contemporary molecular concepts of PD pathophysiology and how they can be harnessed to develop effective imaging probes and therapeutic agents. Further, we will shed light on potential future trends, thereby focusing on potential novel diagnostic tracers and disease-modifying therapeutic interventions
Effectiveness and suitability of vapor heat treatment in disinfestation of export mango fruit, cultivar Abu Samaka, from fruit flies
Sudan has a great potential for the export of mango (Mangifera Indica L.) but fruit flies, mainly Bactrocera dorsalis (Hendel), Ceratitis cosyra (Walker), C. capitata (Wiedmann) and B. zonata (Saunders) are threatening the export industry. The countries importing mango require disinfestation treatment against fruit flies as a quarantine regulation. Effectiveness and suitability of vapor heat treatment (VHT) for disinfestation of the Sudanase mango cultivar Abu Samaka were undertaken in this study. In the VHT, the relative humidity of the treatment chamber was maintained at 99.7% and the temperature of the fruit pulp was raised gradually to reach 46.7°C in 5 hours then kept at this degree for 30 minutes before hydro-cooling for 20 minutes. For evaluation of the effectiveness of the treatment, naturally and artificially infested fruits were examined for fruit flies after treatment and compared with their respective untreated samples. To assess suitability of the treatment with respect to quality of the mango fruit, respiration rate, peel color, weight loss, flesh firmness, ascorbic acid content, total soluble solids, titratable acidity and reducing sugars were measured in the treated and control fruits. The VHT was found effective in disinfestation of the mango cultivar Abu Samka from fruit flies and did not adversely affect the fruit market quality and increased the shelf life
Sero-molecular Epidemiology of Hepatitis E Virus in Blood Donors, Gezira State, Sudan: A Cross-sectional Study
Background: Hepatitis E virus (HEV) is a hepatotropic pathogen that causes significant morbidity and mortality in humans. It is an important causative agent of viral hepatitis outbreaks. This study investigates the serological and molecular prevalence of HEV in blood donors attending the Central Blood Bank in Wad Medani City in Gezira State, Sudan.
Methods: The study adopted a cross-sectional descriptive design. A structured questionnaire was used to collect data concerning demographic information and risk factors associated with HEV transmission. All enrolled participants (N = 300) were screened for HEV IgG antibodies using commercial ELISA kits, then strong positive samples (N = 84) were selected and rescreened for HEV IgM and HEV RNA by RT PCR. SPSS version 24.0 was used for analysis.
Results: Out of 300 male participants, 36.3% (109/300) were positive for HEV IgG. However, only one participant was IgM positive, while the HEV RNA was negative. The highest prevalence rates of the virus were 42 (44.6%) among the age group of 31–40 years, 20 (48.8%) in those who consumed food from outside, 13 (50%) in three to four multiple blood donations, and 5 (62.5%) in those who consumed water from the river source. A significant association of HEV IgG prevalence concerning the occupation of the participants being students or farmers was detected using univariate and multivariate analysis (P-value = 0.007).
Conclusion: High prevalence of HEV IgG was demonstrated among the healthy blood donors in this study. Given the possibility of HEV transmission by transfusion from donors to recipients, we recommend that routine screening for HEV should be adopted by blood banks in Sudan
False Beliefs About Diabetes Mellitus in the Kurdistan Region of Iraq: A Population-Based Study
Background. Diabetes mellitus (DM) is a chronic, non-transmissible health condition distinguished by high blood glucose levels caused by faulty insulin secretion and impaired insulin activity. People play an essential role in preventing and managing their illnesses. Thus, the misconceptions may negatively influence the prevention and management of DM.
The aim of this study was to gauge the extent of knowledge among the general population concerning DM, to determine the prevalence of misconceptions about DM in the community, and to find the factors influencing them.
Methods. A population-based study was conducted in Duhok Province, the Kurdistan Region of Iraq. A total of 2,305 adults were enrolled in the study. The study data were collected by face-to-face interview. The survey questionnaire comprised two sections: the first section included basic demographic characteristics of participants, while the second section consisted of ten questions to identify common misconceptions about DM among participants.
Results. Among the participants, there were 1,406 (61.0%) females. Participants’ age ranged from 18 to 90 years (the mean age: 54 ± 13.69 years). The most common misconceptions positively responded to were “Will I become addicted to insulin if I start taking it?”, followed by“ Does DM occur because of increased sugar intake?”. Male gender was associated with higher level of misconceptions. In addition, the misconceptions were more prevalent among diabetics as they might seek treatment from non-professionals. There was a significant association between education status and the prevalence of misconceptions. Healthcare workers were found to have a better knowledge about DM compared to the general population. Surprisingly, certain myths were prevalent even among healthcare workers.
Conclusions. Certain myths and misconceptions have been pervasive in our society. Actions must be taken to dispel these misconceptions as they lead to an avoidable burden of disease. Therefore, people’s knowledge of DM needs to be enhanced through educational programs, social media, television, newspapers and campaigns
Potential role of biosynthesized silver nanoparticles from Aaronsohnia factorovskyi on Hymenolepis nana in BALB/c mice
ABSTRACT Hymenolepiasis is the most common intestinal tapeworm infection in humans caused by an intestinal cestode, Hymenolepis nana. Praziquantel (PZQ) is the most effective drug among other compounds, however, many cases of drug resistance have been reported. Recent research projects have been focused on finding novel therapeutic agents from medicinal plants. In the present study, Aaronsohnia factorovskyi was used against hymenolepiasis in the forms of plant extract (AF) and biosynthesized nanoparticles (AF-NPs) in comparison to PZQ. The results showed that 100 mg/kg AF and 0.5 mg/kg AF-NPs were the most effective doses at suppressing the fecal egg output by 98.39% and 100%, respectively. After the 10th day of treatment, it was not feasible to detect the presence of H. nana eggs in the fecal sample’s examination in the AF-NPs group. Upon treatment with AF-NPs, there were more improvements in the structure of the intestinal tissue than the effect of AF alone and in comparison, to PZQ. Collectively, results showed that A. factoryviski can be used as an anti-hymenolepiasis treatment with minimum side effects and less cost. Also, it was found that NPs are the most effective way, as it offers a faster recovery rate in comparison to natural plant extract
Maximization of the optical intra-cavity power of whispering-gallery mode resonators via coupling prism
In this paper, a detailed description of the optical coupling into a Whispering Gallery Mode (WGM) resonator through a prism via frustrated total internal reflection (FTIR) is presented. The problem is modeled as three media with planar interfaces and closed expressions for FTIR are given. Then, the curvature of the resonator is taken into account and the mode overlap is theoretically studied. A new analytical expression giving the optimal geometry of a disc-shaped or ring-shaped resonator for maximizing the intra-cavity circulating power is presented. Such expression takes into consideration the spatial distribution of the WGM at the surface of the resonator, thus being more accurate than the currently used expressions. It also takes into account the geometry of the prism. It is shown an improvement in the geometry values used with the current expressions of about 30%. The reason why the pump laser signal can be seen in experiments under critical coupling is explained on this basis. Then, the conditions required for exciting the highest possible optical power inside the resonator are obtained. The aim is to achieve a highly-efficient up-conversion of a THz signal into the optical domain via the second-order nonlinearity of the resonator material.This work has been financially supported by "DiDaCTIC: Desarrollo de un sistema de comunicaciones inalámbrico en rango THz integrado de alta tasa de datos", TEC2013-47753-C3, CAM S2013/ICE-3004 "DIFRAGEOS" projects, "Proyecto realizado con la Ayuda Fundación BBVA a Investigadores y Creadores Culturales 2016" and "Estancias de movilidad de profesores PRX16/00021"
GT2004-53122 TECHNICAL AND ECONOMICAL FEASIBILITY OF GAS TURBINE INLET COOLING USING EVAPORATIVE FOGGING SYSTEM IN TWO DIFFERENT LOCATIONS IN OMAN
ABSTRACT In this paper gas turbine power boost via inlet air evaporative fogging system is evaluated for power plants of 40 MW power output in two different locations in Sultanate of Oman. The cooling effect is quantified using evaporative cooling degree hour (ECDH) approach. The power output boost based on the month with the highest number of evaporative cooling degree hours reaches as high as 20% for both locations.. This is significant in view of the increased air conditioning load during summer months. It is found that the average net present value (NPV) of installing fogging system in Marmul is 6,182,496. It is also found that the purchase and installation costs are paid back within the first six months of system operation and for later years, annual revenue of over $500,000 is generated
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