159 research outputs found
Factors Influencing Adoption of Open Source Software - An Exploratory Study
Open Source Software (OSS), an example of an IS innovation, provides an alternative to proprietary software for organizations. Despite its free availability, OSS has not been universally adopted. While IS innovation has been extensively studied, there is a dearth of research literature on the adoption of OSS. Using a multi-site case study research method and a well known framework on the adoption of IS innovations, we explore this novel phenomenon and uncover critical factors that influence the adoption of OSS in organizations
Integration of Renewable Energy Resources in Microgrid
Microgrid is a new concept in power generation. The Microgrid concept assumes a cluster of loads
and micro sources operating as a single controllable system that provides both power and heat to
its local area. Not much is known about Microgrid behavior as a whole system. Some models exist
which describe the components of a Microgrid. In this paper, model of Microgrids with steady state
and their transient responses to changing inputs are presented. Current models of a fuel cell, microturbines, wind turbine and solar cell have been discussed. Finally a complete model built of
Microgrid including the power sources, their power electronics, and a load and mains model in
MATLAB/Simulink is presented
Validation of the Pittsburgh sleep quality index in community dwelling Ethiopian adults
Implementation of Nanogrids for Future Power System
Microgrid is a new technology in power generation and this system is used to provide power and heat to its
local area, such as cogeneration systems and renewable energy (wind turbines, photovoltaic cells, etc.). They are preferred
for medium or high power applications. Nanogrid most likely to be used in small local loads for rural area as they will be
more economic then the normal grid power system. Nano grids can operate independently or be connected to the mains and
most likely the internal voltage can be utilized as ac or dc. In this research paper a small scale microgrid system is proposed
for smart homes called "Nanogrid". Each houses have small electrical power system from them can be shared among houses.
If it uses a DC system instead of a general AC system, it can reduce energy loss of inverter because each generator doesnât
need an inverter. Furthermore, it can continue to provide a power supply when blackout occurs in the bulk power system. A
model of a nanogrid is developed to simulate the operation of the centralized power control. Finally a Simulink model is
presented for small houses power range 90-285 KW
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Monodisperse nickel-nanoparticles for stereo- and chemoselective hydrogenation of alkynes to alkenes
Here, we report the use of monosaccharides for the preparation of novel nickel nanoparticles (NP), which constitute selective hydrogenation catalysts. For example, immobilization of fructose and Ni(OAc)2 on silica and subsequent pyrolysis under inert atmosphere produced graphitic shells encapsulated Ni-NP with uniform size and distribution. Interestingly, fructose acts as structure controlling compound to generate specific graphitic layers and the formation of monodisperse NP. The resulting stable and reusable catalysts allow for stereo- and chemoselective semihydrogenation of functionalized and structurally diverse alkynes in high yields and selectivity. Š 2019 The Author(s
Satellite Estimation of Chlorophyll-a Using Moderate Resolution Imaging Spectroradiometer (MODIS) Sensor in Shallow Coastal Water Bodies: Validation and Improvement
The size and distribution of Phytoplankton populations are indicators of the ecological status of a water body. The chlorophyll-a (Chl-a) concentration is estimated as a proxy for the distribution of phytoplankton biomass. Remote sensing is the only practical method for the synoptic assessment of Chl-a at large spatial and temporal scales. Long-term records of ocean color data from the MODIS Aqua Sensor have proven inadequate to assess Chl-a due to the lack of a robust ocean color algorithm. Chl-a estimation in shallow and coastal water bodies has been a challenge and existing operational algorithms are only suitable for deeper water bodies. In this study, the Ocean Color 3M (OC3M) derived Chl-a concentrations were compared with observed data to assess the performance of the OC3M algorithm. Subsequently, a regression analysis between in situ Chl-a and remote sensing reflectance was performed to obtain a green-red band algorithm for coastal (case 2) water. The OC3M algorithm yielded an accurate estimate of Chl-a for deep ocean (case 1) water (RMSE = 0.007, r2 = 0.518, p \u3c 0.001), but failed to perform well in the coastal (case 2) water of Chesapeake Bay (RMSE = 23.217, r2 = 0.009, p = 0.356). The algorithm developed in this study predicted Chl-a more accurately in Chesapeake Bay (RMSE = 4.924, r2 = 0.444, p \u3c 0.001) than the OC3M algorithm. The study indicates a maximum band ratio formulation using green and red bands could improve the satellite estimation of Chl-a in coastal waters
Peptide-Based Coacervate-Core Vesicles with Semipermeable Membranes
Coacervates droplets have long been considered as potential protocells to mimic living cells. However, these droplets lack a membrane and are prone to coalescence, limiting their ability to survive, interact, and organize into higher-order assemblies. This work shows that tyrosine-rich peptide conjugates can undergo liquidâliquid phase separation in a well-defined pH window and transform into stable membrane-enclosed protocells by enzymatic oxidation and cross-linking at the liquidâliquid interface. The oxidation of the tyrosine-rich peptides into dityrosine creates a semipermeable, flexible membrane around the coacervates with tunable thickness, which displays strong intrinsic fluorescence, and stabilizes the coacervate protocells against coalescence. The membranes have an effective molecular weight cut-off of 2.5 kDa, as determined from the partitioning of small dyes and labeled peptides, RNA, and polymers into the membrane-enclosed coacervate protocells. Flicker spectroscopy reveals a membrane bending rigidity of only 0.1kBT, which is substantially lower than phospholipid bilayers despite a larger membrane thickness. Finally, it is shown that enzymes can be stably encapsulated inside the protocells and be supplied with substrates from outside, which opens the way for these membrane-bound compartments to be used as molecularly crowded artificial cells capable of communication or as a vehicle for drug delivery.publishedVersio
On-call emergency workload of a general surgical team
ABSTRACT Background: To examine the on-call emergency workload of a general surgical team at a tertiary care teaching hospital to guide planning and provision of better surgical services. Patients and Methods: During six months period from August to January 2007; all emergency calls attended by general surgical team of Surgical Unit II in Accident and Emergency department (A and E) and in other units of Civil, Hospital Karachi, Pakistan were prospectively recorded. Data recorded includes timing of call, diagnosis, operation performed and outcome apart from demography. Results: Total 456 patients (326 males and 130 females) were attended by on-call general surgery team during 30 emergency days. Most of the calls, 191 (41.9%) were received from 8 am to 5 pm. 224 (49.1%) calls were of abdominal pain, with acute appendicitis being the most common specific pathology in 41 (9.0%) patients. Total 73 (16.0%) calls were received for trauma. Total 131 (28.7%) patients were admitted in the surgical unit for urgent operation or observation while 212 (46.5%) patients were discharged from A and E. 92 (20.1%) patients were referred to other units with medical referral accounts for 45 (9.8%) patients. Total 104 (22.8%) emergency surgeries were done and the most common procedure performed was appendicectomy in 34 (32.7%) patients. Conclusion: Major workload of on-call surgical emergency team is dealing with the acute conditions of abdomen. However, significant proportion of patients are suffering from other conditions including trauma that require a holistic approach to care and a wide range of skills and experience. These results have important implications in future healthcare planning and for the better training of general surgical residents
To determine the level of satisfaction among medical students of a public sector medical university regarding their academic activities
<p>Abstract</p> <p>Background</p> <p>An ongoing evaluation system is essential to determine if the academic system in place has worked to produce a better product, hence the objective of our study was to evaluate the satisfaction level among medical students regarding their academic teaching and assessment method and what measures will they suggest for the future to rectify the current situation.</p> <p>This questionnaire based cross sectional study was conducted in a public sector medical university from February to July 2010. A well structured questionnaire was administered to a random sample of 375 final year medical students. However 292 of the students provided informed consent and filled in the questionnaire which included their demographic profile as well as questions in line with the study objective. Data was entered in a Statistical Package for Social Sciences (SPSS version.16) and analyzed using descriptive statistics.</p> <p>Findings</p> <p>The male to female ratio in our study was 1:2. Most of the students (57.2%) were dissatisfied with the quality of teaching in the university. Fifty-seven percent of the participants believed that the current standard of their institute were not at par with those of international medical universities. BCQ's were the mode of examination questions preferred by the majority of the students. Most of the students (66.1%) wanted the university to conduct career planning seminars to help them plan their career.</p> <p>Conclusions</p> <p>These results suggest that the students of public sector medical universities are unsatisfied from current academic facilities and teaching activities. Students recommend increased emphasis on better lectures and practical training as well as a need to incorporate career planning sessions for the students to help plan them their future career paths.</p
Genome-Wide identification and expression analysis of metal tolerance protein gene family in Medicago truncatula under a broad range of heavy metal stress
Metal tolerance proteins (MTPs) encompass plant membrane divalent cation transporters to specifically participate in heavy metal stress resistance and mineral acquisition. However, the molecular behaviors and biological functions of this family in Medicago truncatula are scarcely known. A total of 12 potential MTP candidate genes in the M. truncatula genome were successfully identified and analyzed for a phylogenetic relationship, chromosomal distributions, gene structures, docking analysis, gene ontology, and previous gene expression. M. truncatula MTPs (MtMTPs) were further classified into three major cation diffusion facilitator (CDFs) groups: Mn-CDFs, Zn-CDFs, and Fe/Zn-CDFs. The structural analysis of MtMTPs displayed high gene similarity within the same group where all of them have cation_efflux domain or ZT_dimer. Cis-acting element analysis suggested that various abiotic stresses and phytohormones could induce the most MtMTP gene transcripts. Among all MTPs, PF16916 is the specific domain, whereas GLY, ILE, LEU, MET, ALA, SER, THR, VAL, ASN, and PHE amino acids were predicted to be the binding residues in the ligand-binding site of all these proteins. RNA-seq and gene ontology analysis revealed the significant role of MTP genes in the growth and development of M. truncatula. MtMTP genes displayed differential responses in plant leaves, stems, and roots under five divalent heavy metals (Cd2+, Co2+, Mn2+, Zn2+, and Fe2+). Ten, seven, and nine MtMTPs responded to at least one metal ion treatment in the leaves, stems, and roots, respectively. Additionally, MtMTP1.1, MtMTP1.2, and MtMTP4 exhibited the highest expression responses in most heavy metal treatments. Our results presented a standpoint on the evolution of MTPs in M. truncatula. Overall, our study provides a novel insight into the evolution of the MTP gene family in M. truncatula and paves the way for additional functional characterization of this gene family
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