3,295 research outputs found
Evaluating Behavioral Health Service Need for Sexual and Gender Minorities: A Community-Based Qualitative Study
The LGBTQ community experiences mental health challenges, such as anxiety, depression, and substance use disorders, at rates higher than heterosexual and cisgender counterparts. Given these disparities in mental health, it is crucial that the LGBTQ population has access to mental health services. However, LGBTQ individuals face barriers to accessing mental health care due to service affordability, availability, and/or lack of LGBT-inclusivity. A Place to Nourish your Health (APNH), formerly known as AIDS Project New Haven, has historically provided care to those in New Haven who live with HIV and AIDS. APNH is now seeking to re-define itself as an organization by expanding services to support those experiencing stigma related to gender identity, sexual orientation, addiction, and mental health. Thus, to aid APNH in their service expansion to stigmatized populations, we performed a qualitative community needs assessment in the greater New Haven area to inform where APNH’s priorities should lie in their expansion of services. Findings provided insight into the current mental health landscape of New Haven’s LGBTQ community and led to reccomendatios regarding APNH\u27s expanion of behavoral health services.https://elischolar.library.yale.edu/ysph_pbchrr/1024/thumbnail.jp
MissForest - nonparametric missing value imputation for mixed-type data
Modern data acquisition based on high-throughput technology is often facing
the problem of missing data. Algorithms commonly used in the analysis of such
large-scale data often depend on a complete set. Missing value imputation
offers a solution to this problem. However, the majority of available
imputation methods are restricted to one type of variable only: continuous or
categorical. For mixed-type data the different types are usually handled
separately. Therefore, these methods ignore possible relations between variable
types. We propose a nonparametric method which can cope with different types of
variables simultaneously. We compare several state of the art methods for the
imputation of missing values. We propose and evaluate an iterative imputation
method (missForest) based on a random forest. By averaging over many unpruned
classification or regression trees random forest intrinsically constitutes a
multiple imputation scheme. Using the built-in out-of-bag error estimates of
random forest we are able to estimate the imputation error without the need of
a test set. Evaluation is performed on multiple data sets coming from a diverse
selection of biological fields with artificially introduced missing values
ranging from 10% to 30%. We show that missForest can successfully handle
missing values, particularly in data sets including different types of
variables. In our comparative study missForest outperforms other methods of
imputation especially in data settings where complex interactions and nonlinear
relations are suspected. The out-of-bag imputation error estimates of
missForest prove to be adequate in all settings. Additionally, missForest
exhibits attractive computational efficiency and can cope with high-dimensional
data.Comment: Submitted to Oxford Journal's Bioinformatics on 3rd of May 201
Fermionic topological quantum states as tensor networks
Tensor network states, and in particular projected entangled pair states, play an important role in the description of strongly correlated quantum lattice systems. They do not only serve as variational states in numerical simulation methods, but also provide a framework for classifying phases of quantum matter and capture notions of topological order in a stringent and rigorous language. The rapid development in this field for spin models and bosonic systems has not yet been mirrored by an analogous development for fermionic models. In this work, we introduce a tensor network formalism capable of capturing notions of topological order for quantum systems with fermionic components. At the heart of the formalism are axioms of fermionic matrix-product operator injectivity, stable under concatenation. Building upon that, we formulate a Grassmann number tensor network ansatz for the ground state of fermionic twisted quantum double models. A specific focus is put on the paradigmatic example of the fermionic toric code. This work shows that the program of describing topologically ordered systems using tensor networks carries over to fermionic models
A unified diagrammatic approach to topological fixed point models
We introduce a systematic mathematical language for describing fixed point
models and apply it to the study to topological phases of matter. The framework
established is reminiscent to that of state-sum models and lattice topological
quantum field theories, but is formalized and unified in terms of tensor
networks. In contrast to existing tensor network ansatzes for the study of
ground states of topologically ordered phases, the tensor networks in our
formalism directly represent discrete path integrals in Euclidean space-time.
This language is more immediately related to the Hamiltonian defining the model
than other approaches, via a Trotterization of the respective imaginary time
evolution. We illustrate our formalism at hand of simple examples, and
demonstrate its full power by expressing known families of models in 2+1
dimensions in their most general form, namely string-net models and Kitaev
quantum doubles based on weak Hopf algebras. To elucidate the versatility of
our formalism, we also show how fermionic phases of matter can be described and
provide a framework for topological fixed point models in 3+1 dimensions.Comment: 86 pages and many diagrams, small change
Topological dualities via tensor networks
The ground state of the toric code, that of the two-dimensional class D
superconductor, and the partition sum of the two-dimensional Ising model are
dual to each other. This duality is remarkable inasmuch as it connects systems
commonly associated to different areas of physics -- that of long range
entangled topological order, (topological) band insulators, and classical
statistical mechanics, respectively. Connecting fermionic and bosonic systems,
the duality construction is intrinsically non-local, a complication that has
been addressed in a plethora of different approaches, including dimensional
reduction to one dimension, conformal field theory methods, and operator
algebra. In this work, we propose a unified approach to this duality, whose
main protagonist is a tensor network (TN) assuming the role of an intermediate
translator. Introducing a fourth node into the net of dualities offers several
advantages: the formulation is integrative in that all links of the duality are
treated on an equal footing, (unlike in field theoretical approaches) it is
formulated with lattice precision, a feature that becomes key in the mapping of
correlation functions, and their possible numerical implementation. Finally,
the passage from bosons to fermions is formulated entirely within the
two-dimensional TN framework where it assumes an intuitive and technically
convenient form. We illustrate the predictive potential of the formalism by
exploring the fate of phase transitions, point and line defects, topological
boundary modes, and other structures under the mapping between system classes.
Having condensed matter readerships in mind, we introduce the construction
pedagogically in a manner assuming only minimal familiarity with the concept of
TNs.Comment: 19 pages, 19 figure
Hector, a fast simulator for the transport of particles in beamlines
Computing the trajectories of particles in generic beamlines is an important
ingredient of experimental particle physics, in particular regarding near-beam
detectors. A new tool, Hector, has been built for such calculations, using the
transfer matrix approach and energy corrections. The limiting aperture effects
are also taken into account. As an illustration, the tool was used to simulate
the LHC beamlines, in particular around the high luminosity interaction points
(IPs), and validated with results of the Mad-X simulator. The LHC beam
profiles, trajectories and beta functions are presented. Assuming certain
forward proton detector scenarios around the IP5, acceptance plots, irradiation
doses and chromaticity grids are produced. Furthermore, the reconstruction of
proton kinematic variables at the IP (energy and angle) is studied as well as
the impact of the misalignment of beamline elements.Comment: 40 pages, 20 figures; added references, corrected typos ; submitted
to JINS
An Incremental Learning Method to Support the Annotation of Workflows with Data-to-Data Relations
Workflow formalisations are often focused on the representation of a process with the primary objective to support execution. However, there are scenarios where what needs to be represented is the effect of the process on the data artefacts involved, for example when reasoning over the corresponding data policies. This can be achieved by annotating the workflow with the semantic relations that occur between these data artefacts. However, manually producing such annotations is difficult and time consuming. In this paper we introduce a method based on recommendations to support users in this task. Our approach is centred on an incremental rule association mining technique that allows to compensate the cold start problem due to the lack of a training set of annotated workflows. We discuss the implementation of a tool relying on this approach and how its application on an existing repository of workflows effectively enable the generation of such annotations
Immunization with HIV Gag targeted to dendritic cells followed by recombinant New York vaccinia virus induces robust T-cell immunity in nonhuman primates
Protein vaccines, if rendered immunogenic, would facilitate vaccine development against HIV and other pathogens. We compared in nonhuman primates (NHPs) immune responses to HIV Gag p24 within 3G9 antibody to DEC205 ( DEC-HIV Gag p24 ), an uptake receptor on dendritic cells, to nontargeted protein, with or without poly ICLC, a synthetic double stranded RNA, as adjuvant. Priming s.c. with 60 ?g of both HIV Gag p24 vaccines elicited potent CD4+ T cells secreting IL-2, IFN-γ, and TNF-α, which also proliferated. The responses increased with each of three immunizations and recognized multiple Gag peptides. DEC-HIV Gag p24 showed better cross-priming for CD8+ T cells, whereas the avidity of anti-Gag antibodies was ∼10-fold higher with nontargeted Gag 24 protein. For both protein vaccines, poly ICLC was essential for T- and B-cell immunity. To determine whether adaptive responses could be further enhanced, animals were boosted with New York vaccinia virus (NYVAC)-HIV Gag/Pol/Nef. Gag-specific CD4+ and CD8+ T-cell responses increased markedly after priming with both protein vaccines and poly ICLC. These data reveal qualitative differences in antibody and T-cell responses to DEC-HIV Gag p24 and Gag p24 protein and show that prime boost with protein and adjuvant followed by NYVAC elicits potent cellular immunity
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