713 research outputs found
The role of DJ-1 in enhancing mitochondrial quality control
Thesis (M.A.)--Boston UniversityDJ-1 is a cytosolic sensor for oxidative damage which acts on the Mitochondria. It works to curb the negative effects of high membrane potential in mitochondria, but the mechanism of action is still uncertain. This study measured DJ-1’s potential in enchancing mitochondrial quality control in the context of pancreatic B-cells treated with a palmitate and glucose media to promote glucolipotoxicity (GLT). DJ-1 was proven capable of reversing GLT induced changed in mitochondrial morphology in the arenas of Feret’s diameter, aspect ratio, and form factor. We also showed that the mitochondrial membrane potential did not vary with the presence or absence of DJ-1. In addition, DJ-1 was shown capable of limiting the upward boundary of GLT induced increase in mitochondrial membrane potential. Furthermore, an experiment using INS1 cells with GFP-LC3 showed that DJ-1 can decrease the average number of autophagosomes in the cell
It is advisor attitudes that are likely to shape students’ attitudes towards questionable research practices
In debates on the validity of academic research findings, focus has been drawn to socalled questionable research practices, commonly understood to encompass a laundry list of behaviours that can increase the likelihood of statistically significant (and so more publishable) results. Anand Krishna and Sebastian M. Peter report on research examining attitudes to questionable research practices among students who have recently completed their theses. Although almost half had engaged in at least one questionable practice, the practices students most often admitted to were issues of reporting results, many of which can be solved by adopting open science standards of data sharing. Among the more important findings was that advisor attitudes matter: if students thought their thesis advisors endorsed questionable practices, they were more likely to admit engaging in such practices
A revision of the genus Dehaasia (Lauraceae) in the Indo-Burmese region
A taxonomic revision of the genus Dehaasia Blume is presented for the Indo-Burmese region. Four species are recognized, keyed out and treated with references, type citations, synonymy, flowering and fruiting periods, local names and use, habitat, distribution and the specimens examined. Dehassia rangamattiensis is synonymized under D. kurzii. The report of D. firma from the Andaman Islands is based on a misidentified specimen of D. kurzii. The names Dictyodaphne candolleana (basionym of D. candolleana), D. kurzii, D. rangamattiensis and Laurus incrassata (basionym of D. incrassata) are lectotypified. In addition, lectotypification of Cryptocarya cuneata (basionym of D. cuneata), native to Malesia, is appended because the species has often been mistaken for D. candolleana
Impact of Covid-19 Pandemic on Water Pollution in Indian Rivers -- A Case Study
Some of the important critical parameters for assessing the water quality
like pH (Hydrogen ion concentration), DO (Dissolved Oxygen), BOD (Biological
Oxygen Demand), etc., were monitored at different locations in some major
Indian rivers. The results obtained from the study reveals that the critical
parameters had increasing values in some monitoring locations, decreasing
values, and no variation in values at some other places. It is recommended to
have a pH value above 7, higher values of DO, lower values of BOD & FCC (Faecal
Coliform Content) for improved water quality. Overall, the water quality
improved in most Indian rivers. There was no discharge of industrial wastes,
hotels/restaurants wastes, immersing of idols during religious festivals, etc.,
to the rivers during the COVID-19 lockdown. Therefore, enforcement of strict
regulations by the Government of India for disposal of wastes produced from
industrial & domestic activities can significantly reduce the water pollution
levels in the Indian rivers.Comment: 5 pages, 7 figures, 8 table
Estimation of wheat crop evapotranspiration using NDVI vegetation index
The evapotranspiration of the wheat crop grown in Tarafeni South Main Canal (TSMC) irrigation command area of West Bengal, India was estimated based on Normalized Difference Vegetation Index (NDVI) from LANDSAT images. The crop evapotranspiration (ETc) of wheat crop was estimated using the crop coefficient (Kc) maps and the reference evapotranspiration (ETo) in the TSMC irrigation command area. The ETo was estimated from the well known temperature based ETo estimation method, i.e. FAO-24 modified Blaney-Criddle method using measured maximum and minimum air temperatures data during January 2011 in the command area. The Kc maps were mapped in ARC GIS software using procured LANDSAT images for the study period. The area under wheat crop was clipped from land use/land cover map generated from LANDSAT image of January, 2011 for winter season. Further, the crop evapotranspiration map was obtained by multiplying Kc map with the estimated ETo value i.e., 5.76 mm/day for a particular day. The maximum crop evapotranspiration computed for Rabi crop was 5.57 mm/ day, whereas minimum was 1.59 mm/day for the TSMC command area
Design of a Class-AB Amplifier for a 1.5 Bit MDAC of a 12 Bit 100MSPS Pipeline ADC
The basic building block of a pipeline analog-to-digital converter (ADC) is the multiplying digital-to-analog converter (MDAC). The performance of the MDAC significantly depends on the performance of the operational amplifier and calibration techniques. To reduce the complexity of calibration, the operational amplifier needs to have high-linearity, high bandwidth and moderate gain.
In this work, the Op-amp specifications were derived from the pipeline ADC requirements. A novel class-AB bias scheme with feed-forward compensation, which provides high linearity and bandwidth consuming low power is proposed. The advantages of the new topology over Monticelli bias scheme and Miller’s compensated amplifiers is explained. The amplifier is implemented in IBM 130nm technology and the MDAC design is used as a test bench to characterize the Op-amp performance. The proposed architecture performance is compared with class A and class-AB output stage amplifiers with Miller’s compensation reported in literature. The proposed class-AB amplifier with feed forward compensation provides an open loop gain of 47dB, unit gain bandwidth of 1040 MHz and IM3 of 75dB consuming 3.88mA current. The amplifier provides the required linearity and bandwidth at much lower power consumption than the amplifiers using conventional class-AB bias schemes
Sublinear Approximation Algorithm for Nash Social Welfare with XOS Valuations
We study the problem of allocating indivisible goods among agents with
the objective of maximizing Nash social welfare (NSW). This welfare function is
defined as the geometric mean of the agents' valuations and, hence, it strikes
a balance between the extremes of social welfare (arithmetic mean) and
egalitarian welfare (max-min value). Nash social welfare has been extensively
studied in recent years for various valuation classes. In particular, a notable
negative result is known when the agents' valuations are complement-free and
are specified via value queries: for XOS valuations, one necessarily requires
exponentially many value queries to find any sublinear (in ) approximation
for NSW. Indeed, this lower bound implies that stronger query models are needed
for finding better approximations. Towards this, we utilize demand oracles and
XOS oracles; both of these query models are standard and have been used in
prior work on social welfare maximization with XOS valuations.
We develop the first sublinear approximation algorithm for maximizing Nash
social welfare under XOS valuations, specified via demand and XOS oracles.
Hence, this work breaks the -approximation barrier for NSW maximization
under XOS valuations. We obtain this result by developing a novel connection
between NSW and social welfare under a capped version of the agents'
valuations. In addition to this insight, which might be of independent
interest, this work relies on an intricate combination of multiple technical
ideas, including the use of repeated matchings and the discrete moving knife
method. In addition, we partially complement the algorithmic result by showing
that, under XOS valuations, an exponential number of demand and XOS queries are
necessarily required to approximate NSW within a factor of .Comment: 41 page
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