1,892 research outputs found

    Income and Happiness in Afghanistan: Do Insecurity and Violence Matter?

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    We examine the relationship between household income and happiness in Afghanistan and the moderating roles of fear of insecurity and experiencing violence. Our study is based on surveys conducted by the Asia Foundation from 2014 to 2021 across 34 provinces in Afghanistan. Employing fixed effects ordered logit regressions, our results reveal a positive association between income and happiness. Additionally, we find a negative association between fear of insecurity, experiencing violence, and happiness. Among individuals with higher incomes and a fear of insecurity, the probability of having a high level of happiness declines by about 2.4% points when compared to those without such fear. Furthermore, for individuals with higher incomes who have experienced violence, the probability of having a high level of happiness declines by about 3.8% points when compared to those who have not experienced violence. However, for individuals with low incomes, insecurity and violence do not significantly impact their predicated level of happiness. This result can be attributed to two main issues. First, in conflict-affected areas, high-income individuals not only encounter the inherent dangers of their environment and the constant threat of terrorism, but also face increased risk of asset loss and institutional mistrust due to rampant corruption. Second, fear of insecurity and experiencing violence are influenced by psychological factors and diminish the positive impact of higher income on happiness. The results are robust to the inclusion of other socio-economic and demographic characteristics of the respondents

    COSMOS 2044. Experiment K-7-19. Pineal physiology in microgravity: Relation to rat gonadal function

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    It is now known that the pineal organ can interact with many endocrine and nonendocrine tissues in a regulatory fashion. Given its key role in the regulation of melatonin synthesis, its high concentration, and that its levels may persist longer than the more rapidly changing melatonin, it was felt that serotonin might give a more accurate assessment of the effects of microgravity on pineal function following recovery of animals from flight. Five-hydroxyindole acetic acid (5-HIAA), a major metabolite of serotonin metabolism, was also measured. One of the most interesting concomitants to spaceflight and exposure to microgravity has been the disturbing alteration in calcium metabolism and resulting skeletal effects. Given the link between exposure to microgravity and perturbation of calcium metabolism and the fact that the pineal is apparently one of the only soft tissues to calcify, pineal calcium content was examined following spaceflight

    Remote preoperative tonic-clonic seizures do not influence outcome after surgery for temporal lobe epilepsy.

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    OBJECTIVES: Tonic-clonic seizures are associated with greater chance of seizure relapse after anterior temporal lobectomy. We investigated whether the interval between the last preoperative tonic-clonic seizure and surgery relates to seizure outcome in patients with drug-resistant mesial temporal lobe epilepsy (MTLE). METHODS: In this retrospective study, patients were prospectively registered in a database from 1986 through 2014. Postsurgical outcome was categorized as seizure freedom or relapse. The relationship between surgical outcome and the interval between the last preoperative tonic-clonic seizure and surgery was investigated. RESULTS: One-hundred seventy-one patients were studied. Seventy nine (46.2%) patients experienced tonic-clonic seizures before surgery. Receiver operating characteristic curve of timing of the last preoperative tonic-clonic seizure was a moderate indicator to anticipate surgery failure (area under the curve: 0.657, significance; 0.016). The best cutoff that maximizes sensitivity and specificity was 27months; with a sensitivity of 0.76 and specificity of 0.60. Cox-Mantel analysis confirmed that the chance of becoming free of seizures after surgery in patients with no or remote history of preoperative tonic-clonic seizures was significantly higher compared with patients with a recent history (i.e., in 27months before surgery) (p=0.0001). CONCLUSIONS: The more remote the occurrence of preoperative tonic-clonic seizures, the better the postsurgical seizure outcome, with at least a two year gap being more favorable. A recent history of tonic-clonic seizures in a patient with MTLE may reflect more widespread epileptogenicity extending beyond the borders of mesial temporal structures

    Multibody dynamic modelling of a direct wind turbine drive train

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    Wind turbines normally have a long operational lifetime and experience a wide range of operating conditions. A representative set of these conditions is considered as part of a design process, as codified in standards. However, operational experience shows that failures occur more frequently than expected, the costlier of these including failures in the main bearings and gearbox. As modern turbines are equipped with sophisticated online systems, an important task is to evaluate the drive train dynamics from online measurement data. In particular, internal forces leading to fatigue can only be determined indirectly from other locations’ sensors. In this contribution, a direct wind turbine drive train is modelled using the floating frame of reference formulation for a flexible multibody dynamics system. The purpose is to evaluate drive train response based on blade root forces and bedplate motions. The dynamic response is evaluated in terms of main shaft deformation and main bearing forces under different wind conditions. The model was found to correspond well to a commercial wind turbine system simulation software (ViDyn

    The determinant factors underlying habitat selectivity and preference for Black fish Capoeta capoeta gracilis (Keyserling 1891) in Siyahrud River (a tributary of Sefidrud River basin)

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    Understanding habitat requirements of aquatic organisms is key factor for sustainable exploitation and biodiversity conservation of riverine ecosystems. The habitat preference in fish has extremely important for the management of fish populations. The habitat requirements of Black fish (Capoeta capoeta gracilis) in Siyahrud River -tributaries of the Sefidrud River in Caspian basin- were studied in 13 stations along the river during October to November 2013. Hydrological characteristics of the river including water velocity, depth and width, slope, altitude, type of substrate materials, and plant coverage were recorded for each station. Ranges of habitat use and habitat selectivity with regard to the availability of habitat units for different variables were measured using HABSEL software. Despite significant correlation between the water velocity and depth, results from multiple regressions showed preference for the depth range of 17 to 38 cm. The results showed that behavioral preference in C. capoeta gracilis for the velocity was between 0.44 and 0.56 m/s. Also, specimens tended to be present in cobble stone substrate. Therefore, the anthropogenic activities over the Siyahrod River changing the river width, depth, substrate and the flow rate may affect the presence and distribution of C. capoeta gracilis in the mentioned river

    Habitat suitability index of Barbus cyri (Heckel, 1843) in Tootkabon River, the South Caspian Sea basin, Iran

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    Knowledge of habitat requirements of aquatic animals plays an important role in fisheries and protection programs of aquatic ecosystems. Hence, this study was conducted to investigate the suitability indexes of habitat use and habitat suitability index (HSI) of Barbus cyri in its distribution range in Tootkabon River. A number of environmental variables, including elevation, water depth, river width, river slope, velocity, substrate type, and average diameter of bed stone, riparian vegetation type and the relative abundance of B. cyri at 13 stations and three replications from the downstream to upstream were examined during November 2013. The results showed that B. cyri mostly selects upper stretches of the river with higher velocity, middle depth, lower width and bed rock substrate i.e.bed with boulder cover and grasslands and also its residential area is of riparian type compared with the available ranges. Habitat selectivity index for B. cyri showed that the elevation is 130-220 m, water depth 18-75 cm, channel width less than 12 m, channel slope 0.5-2.3%, water velocity less than 0.8 m.s-1, bed rock substrate, average diameter of bed stone larger 15-50cm. Presence of these conditions with HSI of 0.798 indicates that Tootkabon River is an excellent habitat for B. cyri

    Half-optical-cycle damped solitons in quadratic nonlinear media

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    In this paper, Using a classical model of the radiation-matter interaction, we show that the propagation of (1 + 1) dimensional few-optical-cycle pulses in quadratic nonlinear media, taking moderate absorption into account, can be described by the Korteweg–de Vries-Burgers’ (KdVB) equation without using the slowly varying envelope approximation. To fulfill this purpose we use the reductive perturbation method and consider the long-wave approximation, assuming that the characteristic frequency of the pulse is much lower than the resonance frequency of the atoms. We also study both analytical and numerical solution of the KdVB equation describing damped few-optical-cycle soliton propagation

    Exact boundaries in sequential testing for phase-type distributions

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    Consider Wald's sequential probability ratio test for deciding whether a sequence of independent and identically distributed observations comes from a specified phase-type distribution or from an exponentially tilted alternative distribution. Exact decision boundaries for given type-I and type-II errors are derived by establishing a link with ruin theory. Information on the mean sample size of the test can be retrieved as well. The approach relies on the use of matrix-valued scale functions associated with a certain one-sided Markov additive process. By suitable transformations, the results also apply to other types of distributions, including some distributions with regularly varying tails
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