93 research outputs found

    Market-based Approaches to Environmental Management: A Review of Lessons from Payment for Environmental Services in Asia

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    Market-based approaches to environmental management, such as payment for environmental services (PES), have attracted unprecedented attention during the past decade. PES policies, in particular, have emerged to realign private and social benefits such as internalizing ecological externalities and diversifying sources of conservation funding as well as making conservation an attractive land-use paradigm. In this paper, we review several case studies from Asia on payment for environmental services to understand how landowners decide to participate in PES schemes. The analysis demonstrates the significance of four major elements facilitating the adoption and implementation of PES schemes: property rights and tenure security, transaction costs, household and community characteristics, communications, and the availability of PES-related information. PES schemes should target win-win options through intervention in these areas, aimed at maintaining the provision of ecological services and improving the conditions for local inhabitants

    Property Rights and Natural Resources: Socio-Economic Heterogeneity and Distributional Implications of Common Property Resource Management

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    Poverty, property rights and distributional implications of community-based resource management have become major topics of discussion and debate in recent years. This study tries to examine the contribution of community forestry to household-level income with particular emphasis on group heterogeneity and equity in benefit distribution. The assessment of household level benefits suggests that poorer households are currently benefiting less in absolute terms from community forestry than less poor households. In terms of the contribution of forests to household income, the study results suggest that the poor are not necessarily more dependent than the rich, a finding that contradicts results from other similar studies. Econometric analysis suggests that income from community forests is related to socio-economic attributes and private resource endowments of households. Households with land and livestock assets, as well as upper caste households gain more from the commons, while better educated households depend less on forest resources. Female-headed households benefit less from community forests, further aggravating the inequity in distribution of benefits. The study makes a number of recommendations to improve community forest management in Nepal, which include, due consideration for community needs in selecting species for community forestry, transferability of user rights, which would allow less endowed households to benefit more, and more and equitable representation of women and disadvantaged groups in forest management committees (JEL Q2, Q23)

    Oscillatory Network Activity in Brain Functions and Dysfunctions

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    Recent experimental studies point to the notion that the brain is a complex dynamical system whose behaviors relating to brain functions and dysfunctions can be described by the physics of network phenomena. The brain consists of anatomical axonal connections among neurons and neuronal populations in various spatial scales. Neuronal interactions and synchrony of neuronal oscillations are central to normal brain functions. Breakdowns in interactions and modifications in synchronization behaviors are usual hallmarks of brain dysfunctions. Here, in this dissertation for PhD degree in physics, we report discoveries of brain oscillatory network activity from two separate studies. These studies investigated the large-scale brain activity during tactile perceptual decision-making and epileptic seizures. In the perceptual decision-making study, using scalp electroencephalography (EEG) recordings of brain potentials, we investigated how oscillatory activity functionally organizes different neocortical regions as a network during a tactile discrimination task. While undergoing EEG recordings, blindfolded healthy participants felt a linear three-dot array presented electromechanically, under computer control, and reported whether the central dot was offset to the left or right. Based on the current dipole modeling in the brain, we found that the source-level peak activity appeared in the left primary somatosensory cortex (SI), right lateral occipital complex (LOC), right posterior intraparietal sulcus (pIPS) and finally left dorsolateral prefrontal cortex (dlPFC) at 45, 130, 160 and 175 ms respectively. Spectral interdependency analysis showed that fine tactile discrimination is mediated by distinct but overlapping ~15 Hz beta and ~80 Hz gamma band large-scale oscillatory networks. The beta-network that included all four nodes was dominantly feedforward, similar to the propagation of peak cortical activity, implying its role in accumulating and maintaining relevant sensory information and mapping to action. The gamma-network activity, occurring in a recurrent loop linked SI, pIPS and dlPFC, likely carrying out attentional selection of task-relevant sensory signals. Behavioral measure of task performance was correlated with the network activity in both bands. In the study of epileptic seizures, we investigated high-frequency (\u3e 50 Hz) oscillatory network activity from intracranial EEG (IEEG) recordings of patients who were the candidates for epilepsy surgery. The traditional approach of identifying brain regions for epilepsy surgery usually referred as seizure onset zones (SOZs) has not always produced clarity on SOZs. Here, we investigated directed network activity in the frequency domain and found that the high frequency (\u3e80 Hz) network activities occur before the onset of any visible ictal activity, andcausal relationships involve the recording electrodes where clinically identifiable seizures later develop. These findings suggest that high-frequency network activities and their causal relationships can assist in precise delineation of SOZs for surgical resection

    Higher Frequency Network Activity Flow Predicts Lower Frequency Node Activity in Intrinsic Low-Frequency BOLD Fluctuations

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    The brain remains electrically and metabolically active during resting conditions. The low-frequency oscillations (LFO) of the blood oxygen level-dependent (BOLD) signal of functional magnetic resonance imaging (fMRI) coherent across distributed brain regions are known to exhibit features of this activity. However, these intrinsic oscillations may undergo dynamic changes in time scales of seconds to minutes during resting conditions. Here, using wavelet-transform based timefrequency analysis techniques, we investigated the dynamic nature of default-mode networks from intrinsic BOLD signals recorded from participants maintaining visual fixation during resting conditions. We focused on the default-mode network consisting of the posterior cingulate cortex (PCC), the medial prefrontal cortex (mPFC), left middle temporal cortex (LMTC) and left angular gyrus (LAG). The analysis of the spectral power and causal flow patterns revealed that the intrinsic LFO undergo significant dynamic changes over time. Dividing the frequency interval 0 to 0.25 Hz of LFO into four intervals slow- 5 (0.01–0.027 Hz), slow-4 (0.027–0.073 Hz), slow-3 (0.073–0.198 Hz) and slow-2 (0.198–0.25 Hz), we further observed significant positive linear relationships of slow-4 in-out flow of network activity with slow-5 node activity, and slow-3 in-out flow of network activity with slow-4 node activity. The network activity associated with respiratory related frequency (slow- 2) was found to have no relationship with the node activity in any of the frequency intervals. We found that the net causal flow towards a node in slow-3 band was correlated with the number of fibers, obtained from diffusion tensor imaging (DTI) data, from the other nodes connecting to that node. These findings imply that so-called resting state is not ‘entirely’ at rest, the higher frequency network activity flow can predict the lower frequency node activity, and the network activity flow can reflect underlying structural connectivity

    Is the Brain’s Inertia for Motor Movements Different for Acceleration and Deceleration?

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    The brain’s ability to synchronize movements with external cues is used daily, yet neuroscience is far from a full understanding of the brain mechanisms that facilitate and set behavioral limits on these sequential performances. This functional magnetic resonance imaging (fMRI) study was designed to help understand the neural basis of behavioral performance differences on a synchronizing movement task during increasing (acceleration) and decreasing (deceleration) metronome rates. In the MRI scanner, subjects were instructed to tap their right index finger on a response box in synchrony to visual cues presented on a display screen. The tapping rate varied either continuously or in discrete steps ranging from 0.5 Hz to 3 Hz. Subjects were able to synchronize better during continuously accelerating rhythms than in continuously or discretely decelerating rhythms. The fMRI data revealed that the precuneus was activated more during continuous deceleration than during acceleration with the hysteresis effect significant at rhythm rates above 1 Hz. From the behavioral data, two performance measures, tapping rate and synchrony index, were derived to further analyze the relative brain activity during acceleration and deceleration of rhythms. Tapping rate was associated with a greater brain activity during deceleration in the cerebellum, superior temporal gyrus and parahippocampal gyrus. Synchrony index was associated with a greater activity during the continuous acceleration phase than during the continuous deceleration or discrete acceleration phases in a distributed network of regions including the prefrontal cortex and precuneus. These results indicate that the brain’s inertia for movement is different for acceleration and deceleration, which may have implications in understanding the origin of our perceptual and behavioral limits

    Amplitude death in nonlinear oscillators with nonlinear coupling

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    Amplitude death is the cessation of oscillations that occurs in coupled nonlinear systems when fixed points are stabilized as a consequence of the interaction. We show here that this phenomenon is very general: it occurs in nonlinearly coupled systems in the absence of parameter mismatch or time delay although time-delayed interactions can enhance the effect. Application is made to synaptically coupled model neurons, nonlinearly coupled Rössler oscillators, as well as to networks of nonlinear oscillators with nonlinear coupling. By suitably designing the nonlinear coupling, arbitrary steady states can be stabilized

    Original Article Social Inequality, Local Leadership and Collective Action: An Empirical Study of Forest Commons

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    Abstract Previous research has identified a range of variables conducive to the self-organization of user groups for participatory resource management, including the physical and technical attributes of the resource, the characteristics of user groups and the nature of institutional arrangements. This paper focuses on household characteristics such as caste and income, and analyzes their impact on the probability of membership in the decision-making unit of local forest management institutions, drawing on primary data from a survey of eight community forest user groups in the mid-hills of Nepal. It shows in particular that members of households belonging to lower-caste groups have a lower probability of being elected as members of the executive committee of user groups. The participation of such households in village meetings, however, also increases the probability of membership within the executive decision-making unit, suggesting that household participation can help to achieve fairer forms of village-level collective action. La recherche sur les groupes participatifs de gestion des ressources a identifie´un large e´ventail de variables favorisant leur e´mergence, y compris les attributs physiques et techniques des ressources en question, les caracte´ristiques des membres utilisateurs, ainsi que la nature des arrangements institutionnels. Cet article se focalise sur certaines caracte´ristiques des me´nages dont sont issus les membres utilisateurs de ces groupes, telles que la caste et le revenu, et analyse leur impact sur la probabilite´d'adhe´sion a`l'organe exe´cutif de groupes locaux de gestion de ressources forestie`re, en se basant sur des donne´es primaires tire´es d'un recensement de huit groupes dans des communaute´s de la zone des collines du Ne´pal. Il est de´montre´que les membres de me´nages appartenant aux groupes de caste infe´rieure ont une probabilite´moindre d'eˆtre e´lu au comite´de direction. Cependant, la simple participation de ces me´nages aux re´unions de leur groupe augmente la probabilite´d'adhe´sion d'un de leur membre a`l'organe exe´cutif, sugge´rant que la participation elle-meˆme peut intrinse`quement promouvoir des formes d'action collective plus justes au niveau local

    Genetic variability, heritability, genetic advance and correlation among yield and yield components of rice (Oryza sativa L.)

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    This study was conducted during summer 2015 at Regional Agriculture Research Station, Dipayal, Doti, Nepal to estimate the genotypic and phenotypic variability, heritability, genetic advance and correlation on grain yield and yield associated traits using 26 advance genotypes of lowland irrigated rice. Analysis of variance revealed the existence of significant difference for days to flowering, maturity, plant height, panicle length, thousand grain weight and grain yield. High heritability was estimated for days to flowering (0.88), maturity (0.79), thousand grain weight (0.48) and plant height (0.43) suggesting these traits are under high genetic control. High phenotypic variation was observed for grain yield (24.87%), number of grains/panicle (22.45%), number of panicles/m2 (20.95%) and straw yield (20.75%) while grain yield had medium (12.02%) and remaining traits showed low genotypic coefficient of variation (<10%). High phenotypic coefficient of variation estimated as compared to genotypic coefficient of variation showed environmental influence on the expression of traits. Grain yield (11.98) and days to flowering (10.32) showed medium and remaining traits sowed low genotypic advance as percent of mean. High to low heritability with moderate to low genotypic advance as percent of mean suggested these traits were governed by non additive gene thus direct selection is not beneficial. Further improvements on yield potentiality and yield traits on these genotypes are suggested by creating variation and selection. Panicle length (r = 0.230), days to flowering (r = 0.247), effective tillers (r = 0.488) and straw yield (r = 0.846) manifested significant positive association with grain yield indicating that yield can be increased if selection applied in favor of those yield components

    Agronomic performance and genotypic diversity for morphological traits among early maize genotypes

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    Detailed information on the genetic diversity between maize germplasm (Zea mays L.) is useful for their systematic and efficient use in breeding programs. Fourteen early maize genotypes were studied to assess their performance and genotypic diversity at Doti, Nepal in 2015. Days to tasseling, days to silking, plant height, ear height, ear length, ear diameter and grain yield were significant among genotypes. Genotype SO3TEY-PO-BM, COMPOL-NIOBP and ACROSS-99402 were found higher yielder with earlier maturity. Days to tasseling (0.85), days to silking (0.82), plant height (0.79), ear length (0.71) and ear diameter (0.66) were found highly heritable traits. Grain yield (0.39) and ear height (0.47) medium and remaining traits showed low heritability. High PCV was observed for grain yield (35.10%), number of plants/plot (34.46%), tesseling silking interval (26.85%), harvested ears/plot (24.45%) and husk cover rating (22.85%) where other traits showed medium to low PCV. Grain yield showed high GCV (21.96%), ear height and husk cover had medium and remaining traits showed low GCV (<10%). Plant height (r₌0.498), harvested plants/plot (r₌0.412), harvested ear/plot (r₌0.762), ear length (r₌0.472) and ear diameter (r₌0.470) showed significant positive correlation with grain yield. The yield can be improved if selection applied in favor of those yield components
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