639 research outputs found
A hybrid memory kernel approach for condensed phase non-adiabatic dynamics
The spin-boson model is a simplified Hamiltonian often used to study
non-adiabatic dynamics in large condensed phase systems, even though it has not
been solved in a fully analytic fashion. Herein, we present an exact analytic
expression for the dynamics of the spin-boson model in the infinitely slow bath
limit and generalize it to approximate dynamics for faster baths. We achieve
the latter by developing a hybrid approach that combines the exact slow-bath
result with the popular NIBA method to generate a memory kernel that is
formally exact to second order in the diabatic coupling but also contains
higher-order contributions approximated from the second order term alone. This
kernel has the same computational complexity as NIBA, but is found to yield
dramatically superior dynamics in regimes where NIBA breaks down---such as
systems with large diabatic coupling or energy bias. This indicates that this
hybrid approach could be used to cheaply incorporate higher order effects into
second order methods, and could potentially be generalized to develop alternate
kernel resummation schemes
Formalizing Size-Optimal Sorting Networks: Extracting a Certified Proof Checker
Since the proof of the four color theorem in 1976, computer-generated proofs
have become a reality in mathematics and computer science. During the last
decade, we have seen formal proofs using verified proof assistants being used
to verify the validity of such proofs.
In this paper, we describe a formalized theory of size-optimal sorting
networks. From this formalization we extract a certified checker that
successfully verifies computer-generated proofs of optimality on up to 8
inputs. The checker relies on an untrusted oracle to shortcut the search for
witnesses on more than 1.6 million NP-complete subproblems.Comment: IMADA-preprint-c
Higher body weight is associated with lower concentrations of progesterone and estrogen in early pregnancy following in vitro fertilization
To evaluate if body weight impacts progesterone and estradiol concentration levels in early pregnancy in women conceiving following single embryo transfer
VAMPS : a website for visualization and analysis of microbial population structures
© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in BMC Bioinformatics 15 (2014): 41, doi:10.1186/1471-2105-15-41.The advent of next-generation DNA sequencing platforms has revolutionized molecular microbial ecology by making the detailed analysis of complex communities over time and space a tractable research pursuit for small research groups. However, the ability to generate 105–108 reads with relative ease brings with it many downstream complications. Beyond the computational resources and skills needed to process and analyze data, it is difficult to compare datasets in an intuitive and interactive manner that leads to hypothesis generation and testing. We developed the free web service VAMPS (Visualization and Analysis of Microbial Population Structures, http://vamps.mbl.edu webcite) to address these challenges and to facilitate research by individuals or collaborating groups working on projects with large-scale sequencing data. Users can upload marker gene sequences and associated metadata; reads are quality filtered and assigned to both taxonomic structures and to taxonomy-independent clusters. A simple point-and-click interface allows users to select for analysis any combination of their own or their collaborators’ private data and data from public projects, filter these by their choice of taxonomic and/or abundance criteria, and then explore these data using a wide range of analytic methods and visualizations. Each result is extensively hyperlinked to other analysis and visualization options, promoting data exploration and leading to a greater understanding of data relationships. VAMPS allows researchers using marker gene sequence data to analyze the diversity of microbial communities and the relationships between communities, to explore these analyses in an intuitive visual context, and to download data, results, and images for publication. VAMPS obviates the need for individual research groups to make the considerable investment in computational infrastructure and bioinformatic support otherwise necessary to process, analyze, and interpret massive amounts of next-generation sequence data. Any web-capable device can be used to upload, process, explore, and extract data and results from VAMPS. VAMPS encourages researchers to share sequence and metadata, and fosters collaboration between researchers of disparate biomes who recognize common patterns in shared data.Funding provided by the National Science Foundation [grant NSF/BDI
0960626 to SMH] and the Sloan Foundation through a collaborative project
with the Microbiology of the Built Environment program
Initial Results From the First Field Expedition of UAPx to Study Unidentified Anomalous Phenomena
In July 2021, faculty from the UAlbany Department of Physics participated in
a week-long field expedition with the organization UAPx to collect data on UAPs
in Avalon, California, located on Catalina Island, and nearby. This paper
reviews both the hardware and software techniques which this collaboration
employed, and contains a frank discussion of the successes and failures, with a
section about how to apply lessons learned to future expeditions. Both
observable-light and infrared cameras were deployed, as well as sensors for
other (non-EM) emissions. A pixel-subtraction method was augmented with other
similarly simple methods to provide initial identification of objects in the
sky and/or the sea crossing the cameras' fields of view. The first results will
be presented based upon approximately one hour in total of triggered
visible/night-vision-mode video and over 600 hours of untriggered (far) IR
video recorded, as well as 55 hours of (background) radiation measurements.
Following multiple explanatory resolutions of several ambiguities that were
potentially anomalous at first, we focus on the primary remaining ambiguity
captured at approximately 4am Pacific Time on Friday, July 16: a dark spot in
the visible/near-IR camera possibly coincident with ionizing radiation that has
thus far resisted a prosaic explanation. We conclude with quantitative
suggestions for serious researchers in this still-nascent field of
hard-science-based UAP studies, with an ultimate goal of identifying UAPs
without confirmation bias toward either mundane or speculative conclusions.Comment: 43 pages, 16 figures, 2 tables, 18 equations, and 64 reference
Introducing a gender-sensitive approach to pre-trial assessment and probation: Evaluation of an innovation in Kenya
This paper evaluates a pioneering project to introduce a gender-sensitive approach to working with women completing probation and community service orders in Kenya. The intervention consisted of context-specific research with women throughout Kenya, leading to adaptations to existing probation tools, followed by pilot implementation of a gender-sensitive approach. The evaluation explores the relevance, effectiveness and sustainability of the intervention and presents opinions of implementing probation officers and sector experts. Findings suggest that the project genuinely broke new ground in terms of research on gender-sensitivity and quality of pre-trial reporting for women. Close adherence to the UN Bangkok Rules means the model and lessons are applicable both domestically and globally
Impact of periodic health examination on surgical treatment for uterine fibroids in Beijing: a case-control study
<p>Abstract</p> <p>Background</p> <p>During the past 2 decades, there has been a rapid proliferation of "health examination center (HEC)" across China. The effects of their services on public's health have not been systemically investigated. This study aimed to assess the impact of periodic health examination (PHE) at HEC on surgical treatment for uterine fibroids in Beijing residents.</p> <p>Methods</p> <p>We identified 224 patients with a primary diagnosis of uterine fibroids who had surgical treatment at four Level-1 general hospitals in Beijing, from June 1, 2009 to October 20, 2009. Controls were women who did not have surgery for uterine fibroids, matched (1:1 ratio) for age (within 2 years). A standard questionnaire was used to inquire about whether participants had PHE at HEC during the previous 2 years.</p> <p>Results</p> <p>PHE at HEC within 2 years were associated with surgical treatment for uterine fibroids. Odds ratios was 4.05 (95% CI, 2.61-6.29 P < 0.001), after adjustment for marital status, whether have children, annual family income, health insurance, education level and self-rated uterine fibroids-related symptom severity.</p> <p>Conclusions</p> <p>Our study showed PHE currently provided at HEC in China were associated with significantly increased use of surgical treatment for uterine fibroids in women. Further studies are needed to assess the effects of PHE on clinical as well as on broad societal outcomes in Chinese in contemporary medical settings.</p
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