54 research outputs found

    Assessment of capacity for water resource management: A case study of a small watershed in Nepal

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    Use of local knowledge, increased public participation, and capacity building – singly or in combination – are identified as major strategies to enhance sustainable and integrated management of water. Recently, capacity assessment has been recognized as one of the most effective means to operationalize these strategies in the context of water resource management However, the contemporary literature shows local-level capacity assessment as one of the least explored areas. The literature shows that capacity assessment still lacks conceptual clarity and an implementable framework. Efforts are being made in this direction, but very few focus below the national level. Many such efforts are theoretical, and those that do focus at the local level are confined to assessment of local needs. Understandings developed through a systematic review of the literature were taken to a small sub-watershed, Gerkhu Khola, in Nepal and an iterative approach imbedded in a case study was used to explore the issue of capacity assessment The approach was based on situated facts, integration and application of both qualitative and quantitative methods, and development of a method of assessment at the local-level with active participation of local-level stakeholders. The iterative approach also included local-level analysis of sustainable water resource management principles as given by the International Conference on Water and Environment in 1992 (The Dublin Principles: 1992), which helped to define an ideal condition for water resource management. Therefore, the thrust of this thesis is also to examine to what extent the recent ideas developed at the international and national levels are applicable at the local levels. All findings and syntheses of the case study were discussed with the grassroots level stakeholders to better justify and relate the findings to their knowledge and consensus. The findings indicated that a systematic exploration of actions, attitudes and preferences of local people is essential for capacity assessment. It was observed that the local people are able to understand and analyze the relevance of sustainable conditions identified for water resource management viz., finiteness of water, participatory and users\u27 involvement, women\u27s role and the economic value of water. The local reactions to these conditions were demonstrated through sustainable actions, strong attitudinal inclination and ability to prioritize. Locally, capacity assessment is seen both as a solution and a problem. A framework developed based on the findings suggests that capacity assessment should be an iterative process with strong interdependence existing among the different modes of assessment. It is hoped that the framework developed in this thesis will streamline efforts to integrate and synthesize local-level capacity in water resource management. This study also found that the issue of local-level capacity assessment provides a challenging arena for further exploration

    Application of system dynamics for RWSS analysis

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    The paper introduces system dynamics (SD) and simple feedback system of cause and effect; it’s potential for application in rural community development analysis, especially in RWSS interventions. Application of feedback system for RWSS schemes is made for a generic system demonstrating dynamic behavior and interrelation of various factors commonly used in demand responsive approach. Behavior of the demonstrated feed back system is discussed with the findings of field study made for Detailed Demand Assessment Study (DDAS). The DDAS was carried out for RWSS schemes financed by Rural Water Supply and Sanitation Fund Board (RWSSFB) in Nepal. This work is a separate research study utilizing the information of the DDAS field study to demonstrate versatility of SD and to contribute to some extent to the research need indicated in the earlier WEDC conference. The paper concludes with the future applicability of SD for its substantial advantage in addressing RWSS systems to get a holistic, interconnected and multidisciplinary analysis of cause and effects

    Review of recent developments in stimulated emission depletion microscopy: applications on cell imaging

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    Stimulated emission depletion (STED) microscopy is one type of far-field optical technique demonstrated to provide subdiffraction resolution. STED microscopy utilizes a donut-shaped depletion beam to limit the probe volume to be much smaller than a diffraction-limited spot. Resolutions as small as a few tens of nanometers laterally are reported for cell analysis. The different versions of STED microscopes are described and contrasted in terms of their applicability for biological imaging. Finally, we suggest likely avenues for improving the performance and increasing the utility of STED microscopy

    A smartphone microscopic method for rapid screening of cloth facemask fabrics during pandemics

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    Background In pandemics, because of increased demand and subsequent shortage of commercial facemasks, people need to use cloth facemasks, although such masks are reported to provide reduced protection. These masks can be prepared in local levels from different fabric materials. In developing countries, cloth masks are preferable because of low cost and added advantages of reusability. The filtering performance of a cloth facemask depends on the facial fit and on the material properties of fabrics such as porosity, yarn spacing or packing, and pore size. In resource limited settings, an affordable and easy to implement method that can assess the surface properties of cloth facemask fabrics would be important. Methods In this work, we developed a smartphone microscopic method for rapid screening of fabric quality. We measured the field of view of the microscope and as a proof of concept, we implemented the method to examine surfaces of sixteen locally available cloth mask fabrics. Results Out of the 16 masks examined, we found very diverse yarn packing and pore morphology (pore size and shape) in the fabrics. The pore size ranged from ~80 to 720 μm; much larger than respiratory droplet and bio-aerosol. This observation partly explains why such cloth facemasks provide reduced protection to the user during pandemics. The performance of a cloth facemask partly depends on the material properties of fabric such as yarn packing, pore size, porosity. Therefore, the surface properties of fabrics obtained from the smartphone method can be used to get preliminary idea on the facemask quality. We believe that the method can be an affordable and rapid method for selection of better fabrics for cloth facemask during pandemics

    The CP43 Proximal Antenna Complex of Higher Plant Photosystem II Revisited: Modeling and Hole Burning Study. I

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    The final version is available at: http://pubs.acs.org/journal/jpcbfkThe CP43 core antenna complex of photosystem II is known to possess two quasi-degenerate “red”-trap states (Jankowiak, R. et al. J. Phys. Chem. B 2000, 104, 11805). It has been suggested recently ( Zazubovich, V.; Jankowiak, R. J. Lumin. 2007, 127, 245) that the site distribution functions of the red states (A and B) are uncorrelated and that narrow holes are burned in the subpopulations of chlorophylls (Chls) from states A and B that are the lowest-energy Chl in their complex and previously thought not to transfer energy. This model of uncorrelated excitation energy transfer (EET) between the quasidegenerate bands is expanded by taking into account both electron−phonon and vibrational coupling. The model is applied to fit simultaneously absorption, emission, zero-phonon action, and transient hole burned (HB) spectra obtained for the CP43 complex with minimized contribution from aggregation. It is demonstrated that the above listed spectra can be well-fitted using the uncorrelated EET model, providing strong evidence for the existence of efficient energy transfer between the two lowest energy states, A and B (either from A to B or from B to A), in CP43. Possible candidate Chls for the low-energy A and B states are discussed, providing a link between CP43 structure and spectroscopy. Finally, we propose that persistent holes originate from regular NPHB accompanied by the redistribution of oscillator strength due to excitonic interactions, rather than photoconversion involving Chl−protein hydrogen bonding, as suggested before (Hughes J. L. et al. Biochemistry 2006, 45, 12345). In the accompanying paper ( Reppert, M.; Zazubovich, V.; Dang, N. C.; Seibert, M.; Jankowiak, R. J. Phys. Chem. B 2008, 9934), it is demonstrated that the model discussed in this manuscript is consistent with excitonic calculations, which also provide very good fits to both transient and persistent HB spectra obtained under non-line-narrowing conditions.This work was supported by the start-up funding at the Department of Chemistry, Kansas State University (RJ, NCD, MR and BN), and in part by the U.S. Department of Energy (DOE) EPSCoR grant (RJ), Energy Biosciences Program, Basic Energy Sciences, DOE (MS and NCD) and BFU2005-07422-CO2-01; Spain (RP). VZ acknowledges support by NSERC.Peer reviewe

    Site Energies of Active and Inactive Pheophytins in the Reaction Center of Photosystem II from Chlamydomonas Reinhardtii

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    31 Pags. The definitive version is available at: http://pubs.acs.org/journal/jpcbfkIt is widely accepted that the primary electron acceptor in various Photosystem II (PSII) reaction centers (RCs) is pheophytin a (Pheo a) within the D1 protein (PheoD1), while PheoD2 (within the D2 protein) is photochemically inactive. The Pheo site energies, however, have remained elusive, due to inherent spectral congestion. While most researchers over the last two decades assigned the Qy-states of PheoD1 and PheoD2 bands near 678–684 nm and 668–672 nm, respectively, recent modeling [Raszewski et al. Biophys. J. 2005, 88, 986–998; Cox et al. J. Phys. Chem. B 2009, 113, 12364–12374] of the electronic structure of the PSII RC reversed the location of the active and inactive Pheos, suggesting that the mean site energy of PheoD1 is near 672 nm, whereas PheoD2 (~677.5 nm) and ChlD1 (~680 nm) have the lowest energies (i.e., the PheoD2-dominated exciton is the lowest excited state). In contrast, chemical pigment exchange experiments on isolated RCs suggested that both pheophytins have their Qy absorption maxima at 676–680 nm [Germano et al. Biochem. 2001, 40, 11472–11482; Germano et al. Biophys. J. 2004, 86, 1664–1672]. To provide more insight into the site energies of both PheoD1 and PheoD2 (including the corresponding Qx transitions, which are often claimed to be degenerate at 543 nm) and to attest that the above two assignments are most likely incorrect, we studied a large number of isolated RC preparations from spinach and wild-type Chlamydomonas reinhardtii (at different levels of intactness) as well as the Chlamydomonas reinhardtii mutant (D2-L209H), in which the active branch PheoD1 is genetically replaced with chlorophyll a (Chl a). We show that the Qx-/Qy-region site-energies of PheoD1 and PheoD2 are ~545/680 nm and ~541.5/670 nm, respectively, in good agreement with our previous assignment [Jankowiak et al. J. Phys. Chem. B 2002, 106, 8803–8814]. The latter values should be used to model excitonic structure and excitation energy transfer dynamics of the PSII RCs.Partial support to B.N. (involved in calculations) was provided by the NSF EPSCoR Grant. V.Z. (involved in writing the manuscript) acknowledges support by NSERC. R.T.S., R.P., and M.S. were involved in the design and preparation of D2-mutant and RCs. They acknowledge support from USDOE, Photosynthetic Antennae Research Center (R.T.S.), MICIN (Grant AGL2008-00377) in Spain (R.P.), and the U.S. Department of Energy’s Photosynthetic Systems Program within the Chemical Sciences, Geosciences, and Biosciences Division of the Office of Basic Energy Sciences under NREL Contract #DE-AC36-08-GO28308 (M.S.).Peer reviewe

    Deep-learning assisted detection and quantification of (oo)cysts of Giardia and Cryptosporidium on smartphone microscopy images

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    The consumption of microbial-contaminated food and water is responsible for the deaths of millions of people annually. Smartphone-based microscopy systems are portable, low-cost, and more accessible alternatives for the detection of Giardia and Cryptosporidium than traditional brightfield microscopes. However, the images from smartphone microscopes are noisier and require manual cyst identification by trained technicians, usually unavailable in resource-limited settings. Automatic detection of (oo)cysts using deep-learning-based object detection could offer a solution for this limitation. We evaluate the performance of three state-of-the-art object detectors to detect (oo)cysts of Giardia and Cryptosporidium on a custom dataset that includes both smartphone and brightfield microscopic images from vegetable samples. Faster RCNN, RetinaNet, and you only look once (YOLOv8s) deep-learning models were employed to explore their efficacy and limitations. Our results show that while the deep-learning models perform better with the brightfield microscopy image dataset than the smartphone microscopy image dataset, the smartphone microscopy predictions are still comparable to the prediction performance of non-experts.Comment: 18 pages (including supplementary information), 4 figures, 7 tables, submitting to Journal of Machine Learning for Biomedical Imagin
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