794 resultados para LONG-DISTANCE MIGRATION
Resumo:
This paper based on a primary survey of households (2004-05) in the slum clusters of Delhi examines whether migrants are likely to experience upward mobility in their place of destination or alternatively, if they merely transfer their poverty from rural areas to large cities. First, a simple bifurcation of population in terms of poor and non-poor sub-groups is examined along with the incidence of poverty across different categories of occupations and non-workers. Then, an explanation of the variations in per capita expenditure across households is provided, and a binomial logit model (poor/non-poor) is developed identifying the variables which raise (or reduce) the probability of being non-poor (or poor). Next, an estimate of the wellbeing (deprivation) index is derived from factor analysis of a large number of variables including demographic and economic aspects of households. Empirical findings suggest that while duration of migration and the wellbeing index do not have a definite relationship, migrant households who have been in the city for a very long time have a higher wellbeing index on average than those who migrated in the last ten years. This tends to support the view that migrants do not merely transfer rural poverty to urban areas, and further that population mobility yields improvement in the living standard, if only in the very long term. Implementation of "employment-cum-shelter" support schemes in the urban areas may contribute to their wellbeing.
Resumo:
Based on the recent census data this paper analyses the district level rural to urban migration rates (both intra-state and the inter-state) among males and females separately. Both the rates are closely associated irrespective of whether the migrants originate from the rural areas within the state or outside the state. This would suggest that women usually migrate as accompanists of the males. Though many of the relatively poor and backward states actually show large population mobility, which is primarily in search of a livelihood, the mobility of male population is also seen to be prominent in the relatively advanced states like Maharashtra and Gujarat. Rapid migration of rural females within the boundaries of the states is, however, evident across most of the regions. The social networks, which play an important role in the context of migration are prevalent among the short distance migrants and tend to lose their significance with a rise in the distance between the place of origin and destination though there are some exceptions to this phenomenon. Besides the north-south divide in the Indian context is indeed a significant phenomenon with a few exceptions of metropolitan cities. As regards the effect of factors at the place of destination, prospects for better job opportunities are a major determinant of male migration. Low castes and minority groups tend to pull migration through network effects. Among females also these effects are evident though with the inclusion of the male migration rate they become less significant. Finally the paper brings out the policy implications.
Resumo:
The networks need to provide higher speeds than those offered today. For it, considering that in the spectrum radio technologies is the scarcest resource in the development of these technologies and the new developments is essential to maximize the performance of bits per hertz transmitted. Long Term Evolution optimize spectral efficiency modulations with new air interface, and more advanced algorithms radius. These capabilities is the fact that LTE is an IPbased technology that enables end-to-end offer high transmission rates per user and very low latency, ie delay in the response times of the network around only 10 milliseconds, so you can offer any realtime application. LTE is the latest standard in mobile network technology and 3GPP ensure competitiveness in the future, may be considered a technology bridge between 3G networks - current 3.5G and future 4G networks, which are expected to reach speeds of up to 1G . LTE operators provide a simplified architecture but both robust, supporting services on IP technology. The objectives to be achieved through its implementation are ambitious, first users have a wide range of added services like capabilities that currently enjoys with residential broadband access at competitive prices, while the operator will have a network fully IP-based environment, reducing the complexity and cost of the same, which will give operators the opportunity to migrate to LTE directly. A major advantage of LTE is its ability to fuse with existing networks, ensuring interconnection with the same, increasing his current coverage and allowing a data connection established by a user in the environment continue when fade the coverage LTE. Moreover, the operator has the advantage of deploying network gradually, starting initially at areas of high demand for broadband services and expand progressively in line with this. RESUMEN. Las redes necesitan proporcionar velocidades mayores a las ofertadas a día de hoy. Para ello, teniendo en cuenta que en tecnologías radio el espectro es el recurso más escaso, en la evolución de estas tecnologías y en los nuevos desarrollos es esencial maximizar el rendimiento de bits por hercio transmitido. Long Term Evolution optimiza la eficiencia espectral con nuevas modulaciones en la interfaz aire, así como los algoritmos radio más avanzado. A estas capacidades se suma el hecho de que LTE es una tecnología basada en IP de extremo a extremo que permite ofrecer altas velocidades de transmisión por usuario y latencias muy bajas, es decir, retardos en los tiempos de respuesta de la red en torno a sólo 10 milisegundos, por lo que permite ofrecer cualquier tipo de aplicación en tiempo real. LTE es el último estándar en tecnología de redes móviles y asegurará la competitividad de 3GPP en el futuro, pudiendo ser considerada una tecnología puente entre las redes 3G – 3.5G actuales y las futuras redes 4G, de las que se esperan alcanzar velocidades de hasta 1G. LTE proporcionará a las operadoras una arquitectura simplificada pero robusta a la vez, soportando servicios sobre tecnología IP. Los objetivos que se persiguen con su implantación son ambiciosos, por una parte los usuarios dispondrá de una amplia oferta de servicios añadidos con capacidades similares a las que disfruta actualmente con accesos a banda ancha residencial y a precios competitivos, mientras que el operador dispondrá de una red basada en entorno totalmente IP, reduciendo la complejidad y el costo de la misma, lo que dará a las operadoras la oportunidad de migrar a LTE directamente. Una gran ventaja de LTE es su capacidad para fusionarse con las redes existentes, asegurando la interconexión con las mismas, aumentando su actual cobertura y permitiendo que una conexión de datos establecida por un usuario en el entorno LTE continúe cuando la cobertura LTE se desvanezca. Por otra parte el operador tiene la ventaja de desplegar la red LTE de forma gradual, comenzando inicialmente por las áreas de gran demanda de servicios de banda ancha y ampliarla progresivamente en función de ésta.
Resumo:
Sight distance is of major importance for road safety either when designing new roads or analysing the alignment of existing roads. It is essential that available sight distance in roads is long enough for emergency stops or overtaking manoeuvres. Also, it is vital for engineers/researchers that the tools used for that analysis are both powerful and intuitive. Based on ArcGIS, the application to be presented not only performs an exhaustive sight distance calculation, but allows an accurate analysis of 3D alignment, using all new tools, from a Digital Elevation Model and vehicle trajectory. The software has been successfully utilised to analyse several two-lane rural roads in Spain. In addition, the software produces thematic maps representing sight distance in which supplementary information about crashes, traffic flow, speed or design consistency could be included, allowing traffic safety studies.
Resumo:
El WCTR es un congreso de reconocido prestigio internacional en el ámbito de la investigación del transporte y aunque las actas publicadas están en formato digital y sin ISSN ni ISBN, lo consideramos lo suficientemente importante como para que se considere en los indicadores. Policies trying to increase walking within urban mobility modal split usually highlight the importance of the functional patterns and the environmental quality of the urban space as major drivers of citizens modal choices. Functional characteristics would be mainly associated to an appropriate mix of land uses within neighbourhoods, whereas environmental quality would be associated to the characteristics of urban spaces. The purpose of this research is threefold: first, to identify relevant proxy indicators, which could characterize pedestrian-friendly land use mix and environmental quality. Second, to assess, for both traits, existing disparities among neighbourhoods in a major metropolitan area. And finally, to explore the association between both indicators and children mobility patterns: according to their built environment, which neighbourhoods have a greater proportion of children and, how is their mobility? Using data from the 2004 household mobility survey in the 128 neighbourhoods of the municipality of Madrid, this paper concludes that potentially favourable conditions at the neighbourhood level seem to have only a modest influence in,mobility patterns , in terms of both, selection of closer destinations and a higher share of walking within modal split. The citys policy choices, with intensive investment in road and public transport infrastructure may explain why short-distance mobility is not as important as it could have been expected in those neighbourhoods with more pedestrian-friendly conditions. The metropolitan transport system is providing mobility conditions, which make far-away destinations attractive to most citizens.
Resumo:
Localized, chemical two-photon photolysis of caged glutamate was used to map the changes in α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptors caused by long-term synaptic depression (LTD) in cerebellar Purkinje cells. LTD produced by pairing parallel fiber activity with depolarization was accompanied by a decline in the response of Purkinje cells to uncaged glutamate that accounted for both the time course and magnitude of LTD. This depression of glutamate responses was observed not only at the site of parallel fiber stimulation but also at more distant sites. The amount of LTD decreased with distance and was half-maximal 50 μm away from the site of parallel fiber activity. Estimation of the number of parallel fibers active during LTD induction indicates that LTD modified glutamate receptors not only at active synapses but also at 600 times as many inactive synapses on a single Purkinje cell. Therefore, both active and inactive parallel fiber synapses can undergo changes at a postsynaptic locus as a result of associative pre- and postsynaptic activity.
Resumo:
The generalized master equations (GMEs) that contain multiple time scales have been derived quantum mechanically. The GME method has then been applied to a model of charge migration in proteins that invokes the hole hopping between local amino acid sites driven by the torsional motions of the floppy backbones. This model is then applied to analyze the experimental results for sequence-dependent long-range hole transport in DNA reported by Meggers et al. [Meggers, E., Michel-Beyerle, M. E., & Giese, B. (1998) J. Am. Chem. Soc. 120, 12950–12955]. The model has also been applied to analyze the experimental results of femtosecond dynamics of DNA-mediated electron transfer reported by Zewail and co-workers [Wan, C., Fiebig, T., Kelley, S. O., Treadway, C. R., Barton, J. K. & Zewail, A. H. (1999) Proc. Natl. Acad. Sci. USA 96, 6014–6019]. The initial events in the dynamics of protein folding have begun to attract attention. The GME obtained in this paper will be applicable to this problem.
Resumo:
Gamma oscillations synchronized between distant neuronal populations may be critical for binding together brain regions devoted to common processing tasks. Network modeling predicts that such synchrony depends in part on the fast time course of excitatory postsynaptic potentials (EPSPs) in interneurons, and that even moderate slowing of this time course will disrupt synchrony. We generated mice with slowed interneuron EPSPs by gene targeting, in which the gene encoding the 67-kDa form of glutamic acid decarboxylase (GAD67) was altered to drive expression of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor subunit GluR-B. GluR-B is a determinant of the relatively slow EPSPs in excitatory neurons and is normally expressed at low levels in γ-aminobutyric acid (GABA)ergic interneurons, but at high levels in the GAD-GluR-B mice. In both wild-type and GAD-GluR-B mice, tetanic stimuli evoked gamma oscillations that were indistinguishable in local field potential recordings. Remarkably, however, oscillation synchrony between spatially separated sites was severely disrupted in the mutant, in association with changes in interneuron firing patterns. The congruence between mouse and model suggests that the rapid time course of AMPA receptor-mediated EPSPs in interneurons might serve to allow gamma oscillations to synchronize over distance.
Resumo:
In adult rodents, neural progenitor cells in the subependymal (SZ) zone of the lateral cerebral ventricle generate neuroblasts that migrate in chains via the rostral migratory stream (RMS) into the olfactory bulb (OB), where they differentiate into interneurons. However, the existence of this neurogenic migratory system in other mammals has remained unknown. Here, we report the presence of a homologue of the rodent SZ/RMS in the adult macaque monkey, a nonhuman Old World primate with a relatively smaller OB. Our results—obtained by using combined immunohistochemical detection of a marker for DNA replication (5-bromodeoxyuridine) and several cell type-specific markers—indicate that dividing cells in the adult monkey SZ generate neuroblasts that undergo restricted chain migration over an extended distance of more than 2 cm to the OB and differentiate into granule interneurons. These findings in a nonhuman primate extend and support the use of the SZ/RMS as a model system for studying neural regenerative mechanisms in the human brain.
Resumo:
Slow potential recording was used for long-term monitoring of the penumbra zone surrounding an ischemic region produced by middle cerebral artery (MCA) occlusion in adult hooded rats (n = 32). Four capillary electrodes (El-E4) were chronically implanted at 2-mm intervals from AP -3, L 2 (El) to AP 0, L 5 (E4). Spontaneous or evoked slow potential waves of spreading depression (SD) were recorded during and 4 h after a 1-h MCA occlusion and at 2- to 3-day intervals afterward for 3 weeks. Duration of the initial focal ischemic depolarization was maximal at E4 and decreased with distance from the focus. SD waves in the penumbra zone were high at El and E2, low and prolonged at E3, and almost absent at E4. Amplitude of elicited SD waves was further reduced 3 days later and slowly increased in the following week. Cortical areas displaying marked reduction of SD waves in the first days after MCA occlusion either remained low or showed substantial (60%) recovery, the probability of which decreased with the duration of the initial focal ischemic depolarization and increased with the distance from the focus. It is concluded that the outcome of ischemia monitored by long-term SD recovery in the perifocal region can be partly predicted from the acute signs of MCA occlusion.