428 research outputs found

    Understanding the impact of economic shocks on labor market outcomes in developing countries : an application to Indonesia and Mexico

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    In this paper the authors use a search and matching model of multi-sector labor markets, to understand the channels through which economic shocks affect labor market outcomes in developing countries. In the model workers can be employed in agriculture, formal or informal urban jobs, or unemployed. Economic shocks are manifested as either increased turbulence in the formal/informal sectors or a decrease in overall sectoral productivity. By calibrating the model to Indonesia and Mexico, the authors are able to understand how the 1998 Indonesian crisis and the 2001 Mexican recession translated into labor market outcomes. They then venture to simulate how the current financial crisis might affect the allocation of labor and earnings across sectors, in these countries. The results suggest that in both countries past crises have increased the degree of turbulence of the formal sector, increasing job destruction. However, while in Indonesia the crisis affected the overall formal sector productivity, this was not the case in Mexico. This explains the larger blow to formal wages -- relative to the size of the shock- witnessed by Indonesian workers. The response of the informal sector was also different: In both countries the informal sector was able to act as a buffer, as relative earnings increased. However, while in Mexico it became much harder to find informal sector opportunities and easier to keep the job once found; in Indonesia turbulence in the informal sector increased substantially increasing the job destruction rate of informal jobs andlimiting the cushioning role that the informal sector might have played. The agricultural sector was spared from the shock in both countries. In Indonesia, it actually benefited from an unusual exogenous increase in the price of rise. The simulations show that if either the informal or agricultural sectors are spared from the shocks, large reallocations of labor might occur, and the overall effect of the shock is smaller. Instead, if these sectors can’t buffer the shock, the reallocation of labor is much smaller, but earnings in the formal sector drop substantially. The authors also explore the impact of alternative policies. They find that in relatively flexible markets where informality can be seen more as a choice rather than as queuing, unemployment benefits and informal employment subsidies may have paradoxical effects, by discouraging formal search. Instead, policies targeted at creating informal employment and boosting formal TFP growth have the desired effects.Labor Markets,Labor Policies,Markets and Market Access,Banks&Banking Reform,Economic Theory&Research

    Dynamic behaviors in directed networks

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    Motivated by the abundance of directed synaptic couplings in a real biological neuronal network, we investigate the synchronization behavior of the Hodgkin-Huxley model in a directed network. We start from the standard model of the Watts-Strogatz undirected network and then change undirected edges to directed arcs with a given probability, still preserving the connectivity of the network. A generalized clustering coefficient for directed networks is defined and used to investigate the interplay between the synchronization behavior and underlying structural properties of directed networks. We observe that the directedness of complex networks plays an important role in emerging dynamical behaviors, which is also confirmed by a numerical study of the sociological game theoretic voter model on directed networks

    Experimental observation of hidden Berry curvature in inversion-symmetric bulk 2H-WSe2

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    We investigate the hidden Berry curvature in bulk 2H-WSe2 by utilizing the surface sensitivity of angle resolved photoemission (ARPES). The symmetry in the electronic structure of transition metal dichalcogenides is used to uniquely determine the local orbital angular momentum (OAM) contribution to the circular dichroism (CD) in ARPES. The extracted CD signals for the K and K' valleys are almost identical but their signs, which should be determined by the valley index, are opposite. In addition, the sign is found to be the same for the two spin-split bands, indicating that it is independent of spin state. These observed CD behaviors are what are expected from Berry curvature of a monolayer of WSe2. In order to see if CD-ARPES is indeed representative of hidden Berry curvature within a layer, we use tight binding analysis as well as density functional calculation to calculate the Berry curvature and local OAM of a monolayer WSe2. We find that measured CD-ARPES is approximately proportional to the calculated Berry curvature as well as local OAM, further supporting our interpretation.Comment: 6 pages, 3 figure

    Entropic sampling dynamics of the globally-coupled kinetic Ising model

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    The entropic sampling dynamics based on the reversible information transfer to and from the environment is applied to the globally coupled Ising model in the presence of an oscillating magnetic field. When the driving frequency is low enough, coherence between the magnetization and the external magnetic field is observed; such behavior tends to weaken with the system size. The time-scale matching between the intrinsic time scale, defined in the absence of the external magnetic field, and the extrinsic time scale, given by the inverse of the driving frequency, is used to explain the observed coherence behavior.Comment: 8 page

    Effects of Photoperiod, Water temperature, and Exogenous Hormones on Spawning and Plasma gonadal Steroid in Starry Flounder, Platichthys stellatus

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    The sexual maturation and spawning of teleosts are regulated by the external environment and the endocrine system. When the environmental conditions are artificially adjusted at a fish farm, the maturity and spawning of fish can be controlled. In this study, sexual maturation and spawning of the starry flounder, Platichthys stellatus, were artificially induced by adjusting the water temperature and photoperiod at a fish farm to accelerate the species’ natural spawning period. One experimental group acted as a control and was exposed to a natural photoperiod and natural water temperature (NPNT). In contrast, another experimental group was exposed to an adjusted environment consisting of a regulated photoperiod and temperature (RPRT). Daylight time was reduced by 10 minutes every 3 days from 13 hours to a duration of 8 hours. The water temperature was first reduced by 1oC every day, starting at 22oC and ending at 8oC, and then raised to 10oC until the spawning period. Both experimental groups were treated with gonadotropin-releasing hormone analog (GnRHa) pellets to induce ovulation. The results show that when the water temperature and photoperiod were artificially controlled, ovulation could be induced 97 days earlier than the natural spawning. Plasma testosterone levels of RPRT and NPNT tended to increase and then decrease 1–2 months before spawning, and plasma levels of 17α,20β-dihydroxy-4-pregnen-3-one increased 1–2 months before spawning. The concentration of estradiol-17β (E2) in plasma was not associated with spawning

    Appropriate number of observations for determining hand hygiene compliance among healthcare workers

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    Abstract We sought to determine the minimum number of observations needed to determine hand hygiene (HH) compliance among healthcare workers. The study was conducted at a referral hospital in South Korea. We retrospectively analyzed the result of HH monitoring from January to December 2018. HH compliance was calculated by dividing the number of observed HH actions by the total number of opportunities. Optimal HH compliance rates were calculated based on adherence to the six-step technique recommended by the World Health Organization. The minimum number of required observations (n) was calculated by the following equation using overall mean value (ρ), absolute precision (d), and confidence interval (CI) (1 − α) [the equation: nZα/22×ρ×(1ρ)/d2{\text{n}} \ge Z_{\alpha /2}^{2} \times \rho \times \left( {1 - \rho } \right)/d^{2} n ≥ Z α / 2 2 × ρ × 1 - ρ / d 2 ]. We considered ds of 5%, 10%, 20%, and 30%, with CIs of 99%, 95%, and 90%. During the study period, 8791 HH opportunities among 1168 healthcare workers were monitored. Mean HH compliance and optimal HH compliance rates were 80.3% and 59.7%, respectively. The minimum number of observations required to determine HH compliance rates ranged from 2 ( dd d : 30%, CI: 90%) to 624 ( dd d : 5%, CI: 99%), and that for optimal HH compliance ranged from 5 ( dd d : 30%, CI: 90%) to 642 ( dd d : 5%, CI: 99%). Therefore, we found that our hospital required at least five observations to determine optimal HH compliance

    Unilateral Trigeminal Mandibular Motor Neuropathy Caused by Tumor in the Foramen Ovale

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    Pure trigeminal motor neuropathy is characterized by trigeminal motor weakness without signs of trigeminal sensory or other cranial nerve involvement. We describe a 63-year-old woman with progressive weakness and atrophy of the left masticatory muscles. She had no sensory disturbance. The diagnosis of pure trigeminal motor neuropathy was made on the basis of clinical and electrophysiologic studies. Magnetic resonance imaging of the brain revealed enhancement of the enlarged mandibular branch of the trigeminal nerve coursing through the left foramen ovale. Our observations suggest that pure trigeminal motor neuropathy can be induced by a tumor

    Fractal Profit Landscape of the Stock Market

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    We investigate the structure of the profit landscape obtained from the most basic, fluctuation based, trading strategy applied for the daily stock price data. The strategy is parameterized by only two variables, p and q. Stocks are sold and bought if the log return is bigger than p and less than -q, respectively. Repetition of this simple strategy for a long time gives the profit defined in the underlying two-dimensional parameter space of p and q. It is revealed that the local maxima in the profit landscape are spread in the form of a fractal structure. The fractal structure implies that successful strategies are not localized to any region of the profit landscape and are neither spaced evenly throughout the profit landscape, which makes the optimization notoriously hard and hypersensitive for partial or limited information. The concrete implication of this property is demonstrated by showing that optimization of one stock for future values or other stocks renders worse profit than a strategy that ignores fluctuations, i.e., a long-term buy-and-hold strategy.Comment: 12 pages, 4 figure

    Characterization of the Fungal Microbiota (Mycobiome) in Healthy and Dandruff-Afflicted Human Scalps

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    The human scalp harbors a vast community of microbial mutualists, the composition of which is difficult to elucidate as many of the microorganisms are not culturable using current culture techniques. Dandruff, a common scalp disorder, is known as a causative factor of a mild seborrheic dermatitis as well as pityriasis versicolor, seborrheic dermatitis, and atopic dermatitis. Lipophilic yeast Malassezia is widely accepted to play a role in dandruff, but relatively few comprehensive studies have been reported. In order to investigate fungal biota and genetic resources of dandruff, we amplified the 26S rRNA gene from samples of healthy scalps and dandruff-afflicted scalps. The sequences were analyzed by a high throughput method using a GS-FLX 454 pyrosequencer. Of the 74,811 total sequence reads, Basidiomycota (Filobasidium spp.) was the most common phylum associated with dandruff. In contrast, Ascomycota (Acremonium spp.) was common in the healthy scalps. Our results elucidate the distribution of fungal communities associated with dandruff and provide new avenues for the potential prevention and treatment of dandruff
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