5,784 research outputs found

    Distributed Delay-Tolerant Strategies for Equality-Constraint Sum-Preserving Resource Allocation

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    This paper proposes two nonlinear dynamics to solve constrained distributed optimization problem for resource allocation over a multi-agent network. In this setup, coupling constraint refers to resource-demand balance which is preserved at all-times. The proposed solutions can address various model nonlinearities, for example, due to quantization and/or saturation. Further, it allows to reach faster convergence or to robustify the solution against impulsive noise or uncertainties. We prove convergence over weakly connected networks using convex analysis and Lyapunov theory. Our findings show that convergence can be reached for general sign-preserving odd nonlinearity. We further propose delay-tolerant mechanisms to handle general bounded heterogeneous time-varying delays over the communication network of agents while preserving all-time feasibility. This work finds application in CPU scheduling and coverage control among others. This paper advances the state-of-the-art by addressing (i) possible nonlinearity on the agents/links, meanwhile handling (ii) resource-demand feasibility at all times, (iii) uniform-connectivity instead of all-time connectivity, and (iv) possible heterogeneous and time-varying delays. To our best knowledge, no existing work addresses contributions (i)-(iv) altogether. Simulations and comparative analysis are provided to corroborate our contributions

    Anaphylaxis: incidence, presentation, causes and outcome in patients in a tertiary care hospital in Karachi, Pakistan

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    Background: Anaphylaxis is a potentially fatal condition requiring immediate resuscitation. Data regarding the epidemiology of anaphylaxis are limited and inconsistent. A reason for the variability was unavailability of a universally acceptable case definition till 2005. We reviewed cases using this new definition Aim: To review the incidence, clinical presentation, cause and outcome of anaphylaxis at a tertiary care center in a low income country. Design: Retrospective, case series Methods: Chart review of all patients discharged from Aga Khan University Hospital between January 1988 - December 2012 (24 years) with anaphylaxis definition as per second National Institute of Allergy and Infection disease/Food Allergy and Anaphylaxis Network Symposium Results: Total of 129 cases were found with mean age of 41.6 years (SD 18.8). Majority of patients had cutaneous features (76.7 %), followed by respiratory (68.9 %), cardiac (64.3 %) and gastrointestinal (20.9 %) symptoms respectively. About 22.4 % of patients had positive history for allergens out of which 31% (n=9) were exposed to the same allergens. The common causes identified for anaphylaxis were drugs (60.5 %), food (16.3 %) and intravenous contrast (10.9 %) respectively. Only 22.5 % of cases received epinephrine as part of their initial management. In 4 patients (3.1 %) the cause of death was attributed to anaphylaxis. Conclusion: Anaphylaxis is a rare but life threatening condition. Though cutaneous features are most common, their absence does not exclude the diagnosis. Drugs were the most common cause and epinephrine was not commonly used as first line agent for its management

    HIV-Related Sexual Risk among African American Men Preceding Incarceration: Associations with Support from Significant Others, Family, and Friends

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    We evaluated the association between social support received from significant others, family, and friends and HIV-related sexual risk behaviors among African American men involved in the criminal justice system. Project DISRUPT is a cohort study among African American men released from prison in North Carolina (N = 189). During the baseline (in-prison) survey, we assessed the amount of support men perceived they had received from significant others, family, and friends. We measured associations between low support from each source (<median value) and participants' sex risk in the 6 months before incarceration. Low levels of social support from significant others, family, or friends were associated with poverty and homelessness, mental disorders, and substance use. Adjusting for age, poverty, and other sources of support, perceiving low support from significant others was strongly associated with multiple partnerships (fully adjusted odds ratio (OR) 2.64, 95% confidence interval (CI) 1.29-5.42). Low significant other support also was strongly associated with sex trade involvement when adjusting for age and poverty status (adjusted OR 3.51, 95% CI 1.25-9.85) but further adjustment for low family and friend support weakened the association (fully adjusted OR 2.81, 95% CI 0.92-8.55). Significant other support was not associated with other sex risk outcomes including concurrent partnerships, anal sex, or sex with an STI/HIV-infected partner. Low family support was associated with multiple partnerships in analyses adjusting for age and poverty (adjusted OR 1.98, 95% CI 1.05-3.76) but the association weakened and was no longer significant after adjusting for other sources of support (fully adjusted OR 1.40, 95% CI 0.65-3.00); family support was not correlated with other risk behaviors. Friend support was not significantly associated with sex risk outcomes. Indicators of overall support from any source were not associated with sex risk outcomes. Helping inmates maintain ties may improve economic security and well-being during community re-entry, while supporting and strengthening relationships with a significant other in particular may help reduce sex risk. Studies should evaluate the protective effects of distinct support sources to avoid masking effects of support and to best understand the influence of social support on health

    Borderline Personality Disorder Symptom Severity and Sexually Transmitted Infection and HIV Risk in African American Incarcerated Men

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    Sexually transmitted infections (STI)/HIV rates are disproportionately high among men involved in the criminal justice system. Mental health disorders, including personality disorders, are also elevated among inmates. Borderline personality disorder (BPD) may be an important risk factor for STI/HIV, yet remains relatively understudied, particularly among inmates

    Depression, Executive Dysfunction, and Prior Economic and Social Vulnerability Associations in Incarcerated African American Men

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    Low executive function (EF) and depression are each determinants of health. We examined the synergy between deficits in EF (impaired cognitive flexibility; >75th percentile on the Wisconsin Card Sorting Test perseverative error score) and depressive symptoms (modified CES-D) and pre-incarceration well-being among incarcerated African American men (N=189). In adjusted analyses, having impaired EF and depression was strongly associated with pre-incarceration food insecurity (OR=3.81, 95% CI: 1.35, 10.77), homelessness (OR=3.00, 95% CI: 1.02, 8.80), concern about bills (OR=3.76, 95% CI: 1.42, 9.95); low significant other support (OR=4.63, 95% CI: 1.62, 13.24), low friend support (OR=3.47, 95% CI: 1.30, 9.26), relationship difficulties (OR=2.86, 95% CI: 1.05, 7.80); and binge drinking (OR=3.62, 95% CI: 1.22, 10.80). Prison-based programs to treat depression and improve problem-solving may improve post-release success

    CXC chemokines exhibit bactericidal activity against multidrug-resistant gram-negative pathogens

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    The continued rise and spread of antimicrobial resistance among bacterial pathogens pose a serious challenge to global health. Countering antimicrobial-resistant pathogens requires a multifaceted effort that includes the discovery of novel therapeutic approaches. Here, we establish the capacity of the human CXC chemokines CXCL9 and CXCL10 to kill multidrug-resistant Gram-negative bacteria, including New Delhi metallo-beta-lactamase-1-producing Klebsiella pneumoniae and colistin-resistant members of the family Enterobacteriaceae that harbor the mobile colistin resistance protein MCR-1 and thus possess phosphoethanolamine-modified lipid A. Colistin-resistant K. pneumoniae isolates affected by genetic mutation of the PmrA/PmrB two-component system, a chromosomally encoded regulator of lipopolysaccharide modification, and containing 4-amino-4-deoxy-l-arabinose-modified lipid A were also found to be susceptible to chemokine-mediated antimicrobial activity. However, loss of PhoP/PhoQ autoregulatory control, caused by disruption of the gene encoding the negative regulator MgrB, limited the bactericidal effects of CXCL9 and CXCL10 in a variable, strain-specific manner. Cumulatively, these findings provide mechanistic insight into chemokine-mediated antimicrobial activity, highlight disparities amongst determinants of colistin resistance, and suggest that chemokine-mediated bactericidal effects merit additional investigation as a therapeutic avenue for treating infections caused by multidrug-resistant pathogens
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