48 research outputs found
Hope Among Resilient African American Adolescents
African American youth have historically been disproportionately affected by an array of environmental stressors that have put them at higher risk for poor adjustment outcomes (Adams III et al., 2003; Mcloyd, 1990). Despite their hardships, not all of these youth fall victim to negative environmental influences (Miller & MacIntosh, 1999). Many exceed expectations and their lives take positive trajectories that lead to positive adaptation (Hunter, 2012; Miller & MacIntosh, 1999). This positive adaptation in spite of significant risk is referred to as resilience (Cicchetti, 2010). While the importance of resilience has been well documented in European Americans, the majority of the scholarship on resilience has ignored African American youth. Therefore, little is known about the factors that contribute to resilience in this population. The literature has suggested that one source of resilience is the construct of hope (Ong, Edwards, & Bergeman, 2006). Hope, as conceptualized by C.R. Snyder (1991), consists of âa cognitive set that is based on a reciprocally-derived sense of successful agency (goal-directed determination) and pathways (planning to meet goals)â (p. 571). Hope has been linked to several positive outcomes in adolescents, but research focused on hope and African American youth is limited. Moreover, there are no published studies that have investigated hope as a resilience factor with African American youth. Therefore, more needs to be understood about how hope may support resilience in this population. The purpose of this study was to explore how resilient African American youth use hope in their lives. Grounded Theory research methodology (Strauss & Corbin, 1990) was used to analyze this construct from the perspective of African American high school students. Seventeen adolescents (5 male, 12 female) participated in individual interviews where they were asked to discuss goals as well as how they generated pathways and maintained movement towards their pursuits in the face of obstacles. Results revealed that participants used hope to: (a) facilitate academic and long-term goals, (b) formulate goals influenced by family role models as well as aspirations for an improved quality of life, and (c) call upon multiple support systems (e.g., family, friends, teachers) and use personal coping strategies (e.g., perseverance) to combat a variety of obstacles (e.g., racial discrimination, procrastination). Additionally, participants also offered ideas for other youth to reach their goals. Limitations of the study, as well as implications of the present study, and future directions for research are also discussed
Precedence-Constrained Min Sum Set Cover
We introduce a version of the Min Sum Set Cover (MSSC) problem in which there are "AND" precedence constraints on the m sets. In the Precedence-Constrained Min Sum Set Cover (PCMSSC) problem, when interpreted as directed edges, the constraints induce an acyclic directed graph. PCMSSC models the aim of scheduling software tests to prioritize the rate of fault detection subject to dependencies between tests.
Our greedy scheme for PCMSSC is similar to the approaches of Feige, Lovasz, and, Tetali for MSSC, and Chekuri and Motwani for precedence-constrained scheduling to minimize weighted completion time. With a factor-4 increase in approximation ratio, we reduce PCMSSC to the problem of
finding a maximum-density precedence-closed sub-family of sets, where density is the ratio of sub-family union size to cardinality. We provide a greedy factor-sqrt m algorithm for maximizing density; on forests of in-trees, we show this algorithm finds an optimal solution. Harnessing an alternative greedy argument of Chekuri and Kumar for Maximum Coverage with Group Budget Constraints, on forests of out-trees, we design an algorithm with approximation ratio equal to maximum tree height.
Finally, with a reduction from the Planted Dense Subgraph detection problem, we show that its conjectured hardness implies there is no polynomial-time algorithm for PCMSSC with approximation factor in O(m^{1/12-epsilon})
A Cultural Context Lens of Hope
This chapter explores hope theory, measurement (i.e., Childrenâs Hope Scale and Adult Dispositional Hope Scale), and research with regard to diverse racial and ethnic groups. Utilizing a cultural context lens, a case study of a Latina adolescent without documentation is used to illustrate how culture influences goals, obstacles, agency, and pathways. Research about the equivalence of hope across groups, including racial and ethnic groups within the United States as well as in other countries, is reviewed. The chapter concludes with a summary of findings regarding hope measurement and hope theory as they apply to various cultural groups and suggestions for future research in the field
Can a Higher Protein/Low Glycemic Index vs. a Conventional Diet Attenuate Changes in Appetite and Gut Hormones Following Weight Loss? : A 3-Year PREVIEW Sub-study
Background: Previous research showed that weight-reducing diets increase appetite sensations and/or circulating ghrelin concentrations for up to 36 months, with transient or enduring perturbations in circulating concentrations of the satiety hormone peptide YY. Objective: This study assessed whether a diet that is higher in protein and low in glycemic index (GI) may attenuate these changes. Methods: 136 adults with pre-diabetes and a body mass index of >= 25 kg/m(2) underwent a 2-month weight-reducing total meal replacement diet. Participants who lost >= 8% body weight were randomized to one of two 34-month weight-maintenance diets: a higher-protein and moderate-carbohydrate (CHO) diet with low GI, or a moderate-protein and higher-CHO diet with moderate GI. Both arms involved recommendations to increase physical activity. Fasting plasma concentrations of total ghrelin and total peptide YY, and appetite sensations, were measured at 0 months (pre-weight loss), at 2 months (immediately post-weight loss), and at 6, 12, 24, and 36 months. Results: There was a decrease in plasma peptide YY concentrations and an increase in ghrelin after the 2-month weight-reducing diet, and these values approached pre-weight-loss values by 6 and 24 months, respectively (P = 0.32 and P = 0.08, respectively, vs. 0 months). However, there were no differences between the two weight-maintenance diets. Subjective appetite sensations were not affected by the weight-reducing diet nor the weight-maintenance diets. While participants regained an average of similar to 50% of the weight they had lost by 36 months, the changes in ghrelin and peptide YY during the weight-reducing phase did not correlate with weight regain. Conclusion: A higher-protein, low-GI diet for weight maintenance does not attenuate changes in ghrelin or peptide YY compared with a moderate-protein, moderate-GI diet.Peer reviewe
No barrier to emergence of bathyal king crabs on the Antarctic shelf
Cold-water conditions have excluded durophagous (skeleton-breaking) predators from the Antarctic seafloor for millions of years. Rapidly warming seas off the western Antarctic Peninsula could now facilitate their return to the continental shelf, with profound consequences for the endemic fauna. Among the likely first arrivals are king crabs (Lithodidae), which were discovered recently on the adjacent continental slope. During the austral summer of 2010â2011, we used underwater imagery to survey a slope-dwelling population of the lithodid Paralomis birsteini off Marguerite Bay, western Antarctic Peninsula for environmental or trophic impediments to shoreward expansion. The population density averaged âŒ4.5 individuals Ă 1,000 m(â2) within a depth range of 1,100â1,500 m (overall observed depth range 841â2,266 m). Images of juveniles, discarded molts, and precopulatory behavior, as well as gravid females in a trapping study, suggested a reproductively viable population on the slope. At the time of the survey, there was no thermal barrier to prevent the lithodids from expanding upward and emerging on the outer shelf (400- to 550-m depth); however, near-surface temperatures remained too cold for them to survive in inner-shelf and coastal environments (<200 m). Ambient salinity, composition of the substrate, and the depth distribution of potential predators likewise indicated no barriers to expansion of lithodids onto the outer shelf. Primary food resources for lithodidsâechinoderms and mollusksâwere abundant on the upper slope (550â800 m) and outer shelf. As sea temperatures continue to rise, lithodids will likely play an increasingly important role in the trophic structure of subtidal communities closer to shore
Multiwavelength Observations of A0620-00 in Quiescence
[Abridged.] We present multiwavelength observations of the black hole binary
system, A0620-00. Using the Cosmic Origins Spectrograph on the Hubble Space
Telescope, we have obtained the first FUV spectrum of A0620-00. The observed
spectrum is flat in the FUV and very faint (with continuum fluxes \simeq 1e -
17 ergs/cm^2/s/A). We compiled the dereddened, broadband spectral energy
distribution of A0620-00 and compared it to previous SEDs as well as
theoretical models. The SEDs show that the source varies at all wavelengths for
which we have multiple samples. Contrary to previous observations, the
optical-UV spectrum does not continue to drop to shorter wavelengths, but
instead shows a recovery and an increasingly blue spectrum in the FUV. We
created an optical-UV spectrum of A0620-00 with the donor star contribution
removed. The non-stellar spectrum peaks at \simeq3000 {\deg}A. The peak can be
fit with a T=10,000 K blackbody with a small emitting area, probably
originating in the hot spot where the accretion stream impacts the outer disk.
However, one or more components in addition to the blackbody are needed to fit
the FUV upturn and the red optical fluxes in the optical-UV spectrum. By
comparing the mass accretion rate determined from the hot spot luminosity to
the mean accretion rate inferred from the outburst history, we find that the
latter is an order of magnitude smaller than the former, indicating that
\sim90% of the accreted mass must be lost from the system if the predictions of
the disk instability model and the estimated interoutburst interval are
correct. The mass accretion rate at the hot spot is 10^5 the accretion rate at
the black hole inferred from the X-ray luminosity. To reconcile these requires
that outflows carry away virtually all of the accreted mass, a very low rate of
mass transfer from the outer cold disk into the inner hot region, and/or
radiatively inefficient accretion.Comment: ApJ, accepte
Genome evolution in the allotetraploid frog Xenopus laevis
To explore the origins and consequences of tetraploidy in the African clawed frog, we sequenced the Xenopus laevis genome and compared it to the related diploid X. tropicalis genome. We characterize the allotetraploid origin of X. laevis by partitioning its genome into two homoeologous subgenomes, marked by distinct families of ???fossil??? transposable elements. On the basis of the activity of these elements and the age of hundreds of unitary pseudogenes, we estimate that the two diploid progenitor species diverged around 34 million years ago (Ma) and combined to form an allotetraploid around 17-18 Ma. More than 56% of all genes were retained in two homoeologous copies. Protein function, gene expression, and the amount of conserved flanking sequence all correlate with retention rates. The subgenomes have evolved asymmetrically, with one chromosome set more often preserving the ancestral state and the other experiencing more gene loss, deletion, rearrangement, and reduced gene expression.ope
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Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.
Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (nâ=â143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (nâ=â152), or no hydrocortisone (nâ=â108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (nâ=â137), shock-dependent (nâ=â146), and no (nâ=â101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707
Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19
IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19.
Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19.
DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 nonâcritically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022).
INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (nâ=â257), ARB (nâ=â248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; nâ=â10), or no RAS inhibitor (control; nâ=â264) for up to 10 days.
MAIN OUTCOMES AND MEASURES The primary outcome was organ supportâfree days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes.
RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ supportâfree days among critically ill patients was 10 (â1 to 16) in the ACE inhibitor group (nâ=â231), 8 (â1 to 17) in the ARB group (nâ=â217), and 12 (0 to 17) in the control group (nâ=â231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ supportâfree days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively).
CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes.
TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570
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