1,085 research outputs found

    Asset depletion among the poor: Does gender matter? The case of urban households in Thailand

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    The paper analytically and empirically examines the issue of gender inequality in household wealth in the form of tangible assets among urban poor households Thailand. It seeks to answer the following questions: (1) is there a gendered pattern of asset ownership between husbands and wives; 2) during times of crises, is there a gendered pattern of asset depletion and 3) does asset depletion impact on men and women differently in regards to their income earnings capabilities? The answers are especially important since asset ownership and access impact the form of coping mechanisms and income earnings of men and women, hence on their individual well-being as well as the longer term well-being of the household. This paper joins in the recent efforts in the literature in investigating gender differences in asset ownership and depletion. In particular, we explore analytically and empirically this type of gender inequality among 135 couples, with and without dependents using quantitative and qualitative data drawn from a random sample of 152 urban, low-income households in Bangkok (Thailand) in 2002. The multi-purpose survey included information at the level of the individual respondent on accumulated tangible or physical assets as well as the status of those owned assets six months later. Both husband and wife were interviewed separately and the data gathered from the multi-visit interviews include pertinent household and individual information, employment, credit as well as household decision making issues, division of tasks and earnings allocation for various expenses. Tobit and probit tests are used to examine the varied factors that may affect the gendered pattern of asset depletion and whether there are any significant differences in asset depletion between men and women in the same households. In addition, two probit models are estimated in order to determine the effects of various individual and household characteristics on the probability of pawning or selling real assets and more specifically, business-related assets . The empirical results demonstrate that, alongside gender equality in employment opportunities and earnings, there is need to raise the importance of and promote advocacy for gender equality in wealth and assets, both public as well as private, and for policy interventions that addresses the gender-wealth gap

    A spectrally-accurate FVTD technique for complicated amplification and reconfigurable filtering EMC devices

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    The consistent and computationally economical analysis of demanding amplification and filtering structures is introduced in this paper via a new spectrally-precise finite-volume time-domain algorithm. Combining a family of spatial derivative approximators with controllable accuracy in general curvilinear coordinates, the proposed method employs a fully conservative field flux formulation to derive electromagnetic quantities in areas with fine structural details. Moreover, the resulting 3-D operators assign the appropriate weight to each spatial stencil at arbitrary media interfaces, while for periodic components the domain is systematically divided to a number of nonoverlapping subdomains. Numerical results from various real-world configurations verify our technique and reveal its universality

    Evaluating performance of neural codes in neural communication networks

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    Information needs to be appropriately encoded to be reliably transmitted over a physical media. Similarly, neurons have their own codes to convey information in the brain. Even though it is well-know that neurons exchange information using a pool of several protocols of spatial-temporal encodings, the suitability of each code and their performance as a function of the network parameters and external stimuli is still one of the great mysteries in Neuroscience. This paper sheds light into this problem considering small networks of chemically and electrically coupled Hindmarsh-Rose spiking neurons. We focus on the mathematical fundamental aspects of a class of temporal and firing-rate codes that result from the neurons' action-potentials and phases, and quantify their performance by measuring the Mutual Information Rate, aka the rate of information exchange. A particularly interesting result regards the performance of the codes with respect to the way neurons are connected. We show that pairs of neurons that have the largest rate of information exchange using the interspike interval and firing-rate codes are not adjacent in the network, whereas the spiking-time and phase codes promote large exchange of information rate from adjacent neurons. This result, if possible to extend to larger neural networks, would suggest that small microcircuits of fully connected neurons, also known as cliques, would preferably exchange information using temporal codes (spiking-time and phase codes), whereas on the macroscopic scale, where typically there will be pairs of neurons that are not directly connected due to the brain's sparsity, the most efficient codes would be the firing rate and interspike interval codes, with the latter being closely related to the firing rate code

    Dynamic range in the C.elegans brain network

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    We study external electrical perturbations and their responses in the brain dynamic network of the Caenorhabditis eleganssoil worm, given by the connectome of its large somatic nervous system. Our analysis is inspired by a realistic experiment where one stimulates externally specific parts of the brain and studies the persistent neural activity triggered in other cortical regions. In this work, we perturb groups of neurons that form communities, identified by the walktrap community detection method, by trains of stereotypical electrical Poissonian impulses and study the propagation of neural activity to other communities by measuring the corresponding dynamic ranges and Steven law exponents. We show that when one perturbs specific communities, keeping the rest unperturbed, the external stimulations are able to propagate to some of them but not to all. There are also perturbations that do not trigger any response. We found that this depends on the initially perturbed community. Finally, we relate our findings for the former cases with low neural synchronization, self-criticality, and large information flow capacity, and interpret them as the ability of the brainnetwork to respond to external perturbations when it works at criticality and its information flow capacity becomes maximal

    Unfolding the procedure of characterizing recorded ultra low frequency, kHZ and MHz electromagetic anomalies prior to the L'Aquila earthquake as pre-seismic ones. Part I

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    Ultra low frequency, kHz and MHz electromagnetic anomalies were recorded prior to the L'Aquila catastrophic earthquake that occurred on April 6, 2009. The main aims of this contribution are: (i) To suggest a procedure for the designation of detected EM anomalies as seismogenic ones. We do not expect to be possible to provide a succinct and solid definition of a pre-seismic EM emission. Instead, we attempt, through a multidisciplinary analysis, to provide elements of a definition. (ii) To link the detected MHz and kHz EM anomalies with equivalent last stages of the L'Aquila earthquake preparation process. (iii) To put forward physically meaningful arguments to support a way of quantifying the time to global failure and the identification of distinguishing features beyond which the evolution towards global failure becomes irreversible. The whole effort is unfolded in two consecutive parts. We clarify we try to specify not only whether or not a single EM anomaly is pre-seismic in itself, but mainly whether a combination of kHz, MHz, and ULF EM anomalies can be characterized as pre-seismic one

    Cross-Layer Theoretical Analysis of NC-aided Cooperative ARQ Protocols in Correlated Shadowed Environments

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    In this paper, we propose a cross-layer analytical model for the study of network coding (NC)-based Automatic Repeat reQuest (ARQ) medium access control (MAC) protocols in correlated slow-faded (shadowed) environments, where two end nodes are assisted by a cluster of relays to exchange data packets. The goal of our work is threefold: 1) to provide general physical-layer theoretical expressions for estimating crucial network parameters (i.e., network outage probability and expected size of the active relay set), applicable in two-way communications; 2) to demonstrate how these expressions are incorporated into theoretical models of the upper layers (i.e., MAC); and 3) to study the performance of a recently proposed NC-aided cooperative ARQ (NCCARQ) MAC protocol under correlated shadowing conditions. Extensive Monte Carlo experiments have been carried out to validate the efficiency of the developed analytical model and to investigate the realistic performance of NCCARQ. Our results indicate that the number of active relays is independent of the shadowing correlation in the wireless links and reveal intriguing tradeoffs between throughput and energy efficiency, highlighting the importance of cross-layer approaches for the assessment of cooperative MAC protocols

    Stability of Simple Periodic Orbits and Chaos in a Fermi -- Pasta -- Ulam Lattice

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    We investigate the connection between local and global dynamics in the Fermi -- Pasta -- Ulam (FPU) β\beta -- model from the point of view of stability of its simplest periodic orbits (SPOs). In particular, we show that there is a relatively high qq mode (q=2(N+1)/3)(q=2(N+1)/{3}) of the linear lattice, having one particle fixed every two oppositely moving ones (called SPO2 here), which can be exactly continued to the nonlinear case for N=5+3m,m=0,1,2,...N=5+3m, m=0,1,2,... and whose first destabilization, E2uE_{2u}, as the energy (or β\beta) increases for {\it any} fixed NN, practically {\it coincides} with the onset of a ``weak'' form of chaos preceding the break down of FPU recurrences, as predicted recently in a similar study of the continuation of a very low (q=3q=3) mode of the corresponding linear chain. This energy threshold per particle behaves like E2uNN2\frac{E_{2u}}{N}\propto N^{-2}. We also follow exactly the properties of another SPO (with q=(N+1)/2q=(N+1)/{2}) in which fixed and moving particles are interchanged (called SPO1 here) and which destabilizes at higher energies than SPO2, since E1uNN1\frac{E_{1u}}{N}\propto N^{-1}. We find that, immediately after their first destabilization, these SPOs have different (positive) Lyapunov spectra in their vicinity. However, as the energy increases further (at fixed NN), these spectra converge to {\it the same} exponentially decreasing function, thus providing strong evidence that the chaotic regions around SPO1 and SPO2 have ``merged'' and large scale chaos has spread throughout the lattice.Comment: Physical Review E, 18 pages, 6 figure

    Anatomical variation of a trifid (trifurcation) lateral root origin of the median nerve

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    Anatomic variations of the brachial plexus are common. Awareness of these variations is of paramount importance in clinical practice mainly in achieving best results in minimal invasive or surgical procedures. The aim of our study was to depict a case of a trifid lateral root origin of the medial nerve. This anatomical variation in the brachial plexus was encountered after dissection in upper extremities in a 90-year-old male cadaver
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