University of North Texas

About: University of North Texas is a education organization based out in Denton, Texas, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 11866 authors who have published 26984 publications receiving 705376 citations. The organization is also known as: Fight, North Texas & UNT.

The Capacity of Symmetric Private Information Retrieval

Abstract: Private information retrieval (PIR) is the problem of retrieving, as efficiently as possible, one out of $K$ messages from $N$ non-communicating replicated databases (each holds all $K$ messages) while keeping the identity of the desired message index a secret from each individual database. Symmetric PIR (SPIR) is a generalization of PIR to include the requirement that beyond the desired message, the user learns nothing about the other $K-1$ messages. The information theoretic capacity of SPIR (equivalently, the reciprocal of minimum download cost) is the maximum number of bits of desired information that can be privately retrieved per bit of downloaded information. We show that the capacity of SPIR is $1-1/N$ regardless of the number of messages $K$ , if the databases have access to common randomness (not available to the user) that is independent of the messages, in the amount that is at least $1/(N-1)$ bits per desired message bit. Otherwise, if the amount of common randomness is less than $1/(N-1)$ bits per message bit, then the capacity of SPIR is zero. Extensions to the capacity region of SPIR and the capacity of finite length SPIR are provided.

The buffering effect of resilience on depression among individuals with spinal cord injury: A structural equation model.

Abstract: OBJECTIVE To translate the theoretical constructs from a model of resilience into a structural equation model and evaluate relationships among the model's theoretical constructs associated with resilience and the occurrence of depressive symptoms. DESIGN Quantitative descriptive research design using structural equation modeling (SEM). PARTICIPANTS Two-hundred and fifty-five individuals with SCI recruited from the Canadian Paraplegic Association (CPA). OUTCOME MEASURES Outcome was measured by the Center for Epidemiologic Studies-Depression Scale. RESULTS The resilience model fit the data relatively well: χ² (200, N = 255) = 451.57, p < .001; χ²/df = 2.26; CFI = .92, RMSEA = 0.070 (90% CI: 0.062-0.079), explaining 77% of the variance in depressive symptomatology. Severity of SCI-related stressors significantly influenced perceived stress (β = .60) and perceived stress, in turn, affected depressive symptoms (β = .66), characteristics of resilience (β = -.43), and social support (β = -.26). The resilience characteristics had an inverse relationship with depressive symptoms (β = -.29). No direct relationship was found between severity of SCI-related stressors and depressive symptoms. CONCLUSIONS Findings provide support for the resilience model and suggests characteristics of resilience "buffer" the perceptions of stress on depressive symptoms. The resilience model may be useful to guide clinical interventions designed to improve the mental health of individuals with SCI.

Ru(II) catalysts supported by hydridotris(pyrazolyl)borate for the hydroarylation of olefins: reaction scope, mechanistic studies, and guides for the development of improved catalysts.

Abstract: Carbon−carbon bond formation is the central method by which synthetic chemists add complexity, which often represents value, to molecules. Uniting a carbon chain with an aromatic substrate to yield an alkyl arene product is thus a molecular means of creating value-added materials. A traditional method for generating alkyl arenes is Friedel−Crafts catalysis, in which an alkyl halide or olefin is activated to react with an aromatic substrate. Unfortunately, despite the development of new generations of solid-state catalysts, the reaction often requires relatively harsh conditions and frequently gives poor to moderate selectivity. Conversely, a halide can first be incorporated into the aromatic ring, and the aryl halide can subsequently be joined by a variety of catalytic coupling techniques. But generating the aryl halide itself can be problematic, and such methods typically are not atom-economical. The addition of aromatic C−H bonds across the C−C double bonds of olefins (olefin hydroarylation) is therefor...