89 research outputs found
Efficient Refuge policies for Bt cotton in India
This study examined the efficient refuge policies for Bt cotton for three cotton growing regions in India. This was accomplished by developing a single-pest, dual-toxin biological model simulating bollworm resistance to the Bt toxin and synthetic pyrethroids, followed by formulating profit functions for Bt and non-Bt cotton for a representative producer in each region. Profits received in subsequent periods were considered in the regulatory model in order to choose a refuge constraint (static problem) or a sequence of refuge policies (dynamic problem) for each region that maximize discounted profits received over 15 years, subject to various economic and biological constraints. Dynamic solutions for the regulatory problem were derived for each region using the Bellman equation. Results suggested that South Indian farmers do not need to grow a refuge, but farmers in the North and Central regions do. Results also suggested that planting sprayed refugia might be more profitable than planting unsprayed refugia. Sensitivity analysis revealed that the refuge requirements were sensitive to the initial Bt resistance level, relative proportion of CBWs in natural refuges, and proportions of heterozygous and homozygous fitnesses in all of the three regions. Moreover, static refugia were found more profitable as compared to dynamic refugia in the North and Central regions.Food Security and Poverty,
Functional Connectivity Dynamics show Resting-State Instability and Rightward Parietal Dysfunction in ADHD
Attention Deficit/Hyperactivity Disorder (ADHD) is one of the most common
neurodevelopmental disorders in children and is characterised by inattention,
impulsiveness and hyperactivity. While several studies have analysed the static
functional connectivity in the resting-state functional MRI (rs-fMRI) of ADHD
patients, detailed investigations are required to characterize the connectivity
dynamics in the brain. In an attempt to establish a link between attention
instability and the dynamic properties of Functional Connectivity (FC), we
investigated the differences in temporal variability of FC between 40 children
with ADHD and 40 Typically Developing (TD) children. Using a sliding-window
method to segment the rs-fMRI scans in time, we employed seed-to-voxel
correlation analysis for each window to obtain time-evolving seed connectivity
maps for seeds placed in the posterior cingulate cortex (PCC) and the medial
prefrontal cortex (mPFC). For each subject, the standard deviation of the voxel
connectivity time series was used as a measure of the temporal variability of
FC. Results showed that ADHD patients exhibited significantly higher
variability in dFC than TD children in the cingulo-temporal, cingulo-parietal,
fronto-temporal, and fronto-parietal networks (). Atypical
temporal variability was observed in the left and right temporal gyri, the
anterior cingulate cortex, and lateral regions of the right parietal cortex.
The observations are consistent with visual attention issues, executive control
deficit, and rightward parietal dysfunction reported in ADHD, respectively.
These results help in understanding the disorder with a fresh perspective
linking behavioural inattention with instability in FC in the brain
An exploration of the effects of low-pressure plasma discharge on the physicochemical properties of chia (Salvia hispanica L.) flour
This work explores the preliminary feasibility of employing the low-pressure coldplasma technology for the modification of the properties of chia flour. Chia flour wasexposed to low pressure plasma in air for 5 min, 10 min, and 15 min, at two differentpower levels (40 W and 60 W). The oils extracted from untreated and treated chiaflour were exhaustively characterized for fatty acid composition, nutritional value,and rancidity indices using thermal calorimetric methods (DSC/TGA). The resultsindicated a significant change in the colour of flour with an increase in lightness.Infrared and ultraviolet spectroscopy indicated changes in the tocopherol groups ofthe oil extracted from plasma treated chia flour. However, the oil extracted fromplasma treated chia flour revealed a loss of conjugated dienes and formation oftrans-fatty acids as seen in conventional hydrogenation of edible oils. DSC and TGAresults revealed better oxidative stability of low-pressure plasma treated oils thancontrol, which was linked to a relative increase of MUFA in the former
Emu Video: Factorizing Text-to-Video Generation by Explicit Image Conditioning
We present Emu Video, a text-to-video generation model that factorizes the
generation into two steps: first generating an image conditioned on the text,
and then generating a video conditioned on the text and the generated image. We
identify critical design decisions--adjusted noise schedules for diffusion, and
multi-stage training--that enable us to directly generate high quality and high
resolution videos, without requiring a deep cascade of models as in prior work.
In human evaluations, our generated videos are strongly preferred in quality
compared to all prior work--81% vs. Google's Imagen Video, 90% vs. Nvidia's
PYOCO, and 96% vs. Meta's Make-A-Video. Our model outperforms commercial
solutions such as RunwayML's Gen2 and Pika Labs. Finally, our factorizing
approach naturally lends itself to animating images based on a user's text
prompt, where our generations are preferred 96% over prior work.Comment: Project page: https://emu-video.metademolab.co
The effectiveness of MAE pre-pretraining for billion-scale pretraining
This paper revisits the standard pretrain-then-finetune paradigm used in
computer vision for visual recognition tasks. Typically, state-of-the-art
foundation models are pretrained using large scale (weakly) supervised datasets
with billions of images. We introduce an additional pre-pretraining stage that
is simple and uses the self-supervised MAE technique to initialize the model.
While MAE has only been shown to scale with the size of models, we find that it
scales with the size of the training dataset as well. Thus, our MAE-based
pre-pretraining scales with both model and data size making it applicable for
training foundation models. Pre-pretraining consistently improves both the
model convergence and the downstream transfer performance across a range of
model scales (millions to billions of parameters), and dataset sizes (millions
to billions of images). We measure the effectiveness of pre-pretraining on 10
different visual recognition tasks spanning image classification, video
recognition, object detection, low-shot classification and zero-shot
recognition. Our largest model achieves new state-of-the-art results on
iNaturalist-18 (91.3%), 1-shot ImageNet-1k (62.1%), and zero-shot transfer on
Food-101 (96.2%). Our study reveals that model initialization plays a
significant role, even for web-scale pretraining with billions of images
Video Endoscopic Inguinal Lymphadenectomy (VEIL) -a prospective critical perioperative assessment of feasibility and morbidity with points of technique in penile carcinoma
Measuring routine childhood vaccination coverage in 204 countries and territories, 1980-2019 : a systematic analysis for the Global Burden of Disease Study 2020, Release 1
Background Measuring routine childhood vaccination is crucial to inform global vaccine policies and programme implementation, and to track progress towards targets set by the Global Vaccine Action Plan (GVAP) and Immunization Agenda 2030. Robust estimates of routine vaccine coverage are needed to identify past successes and persistent vulnerabilities. Drawing from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2020, Release 1, we did a systematic analysis of global, regional, and national vaccine coverage trends using a statistical framework, by vaccine and over time. Methods For this analysis we collated 55 326 country-specific, cohort-specific, year-specific, vaccine-specific, and dosespecific observations of routine childhood vaccination coverage between 1980 and 2019. Using spatiotemporal Gaussian process regression, we produced location-specific and year-specific estimates of 11 routine childhood vaccine coverage indicators for 204 countries and territories from 1980 to 2019, adjusting for biases in countryreported data and reflecting reported stockouts and supply disruptions. We analysed global and regional trends in coverage and numbers of zero-dose children (defined as those who never received a diphtheria-tetanus-pertussis [DTP] vaccine dose), progress towards GVAP targets, and the relationship between vaccine coverage and sociodemographic development. Findings By 2019, global coverage of third-dose DTP (DTP3; 81.6% [95% uncertainty interval 80.4-82 .7]) more than doubled from levels estimated in 1980 (39.9% [37.5-42.1]), as did global coverage of the first-dose measles-containing vaccine (MCV1; from 38.5% [35.4-41.3] in 1980 to 83.6% [82.3-84.8] in 2019). Third- dose polio vaccine (Pol3) coverage also increased, from 42.6% (41.4-44.1) in 1980 to 79.8% (78.4-81.1) in 2019, and global coverage of newer vaccines increased rapidly between 2000 and 2019. The global number of zero-dose children fell by nearly 75% between 1980 and 2019, from 56.8 million (52.6-60. 9) to 14.5 million (13.4-15.9). However, over the past decade, global vaccine coverage broadly plateaued; 94 countries and territories recorded decreasing DTP3 coverage since 2010. Only 11 countries and territories were estimated to have reached the national GVAP target of at least 90% coverage for all assessed vaccines in 2019. Interpretation After achieving large gains in childhood vaccine coverage worldwide, in much of the world this progress was stalled or reversed from 2010 to 2019. These findings underscore the importance of revisiting routine immunisation strategies and programmatic approaches, recentring service delivery around equity and underserved populations. Strengthening vaccine data and monitoring systems is crucial to these pursuits, now and through to 2030, to ensure that all children have access to, and can benefit from, lifesaving vaccines. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.Peer reviewe
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