In this meta‐analytic review, we examined the relation between natural mentoring and youth outcomes in four domains: academic and vocational functioning, social‐emotional development, physical ...health, and psychosocial problems. Natural mentoring relationships are thought to foster positive youth development and buffer against the risks associated with the tumultuous years of adolescence. Two separate meta‐analyses were conducted on the presence of a natural mentor and the quality of the natural mentoring relationship, including thirty studies from 1992 to present. The findings indicated that the presence of a natural mentor was significantly associated with positive youth outcomes (r = .106). A larger effect size was found for the quality of the natural mentoring relationship in terms of relatedness, social support, and autonomy support (r = .208). The largest effect sizes were found for social‐emotional development and academic and vocational functioning. Risk‐status (e.g., teenage mothers, homeless youth, youth in foster care, and youth of alcoholic parents) did not moderate the relation between presence and quality of natural mentoring relationships and youth outcomes, which may indicate that natural mentors are generally beneficial for all youth regardless of risk‐status. Implications for theory and practice concerning the quality of the natural mentoring relationship are discussed.
Highlights
The presence of a natural mentor is associated with positive youth outcomes.
A larger impact was found for quality of the natural mentoring relationship.
Social‐emotional & academic and vocational functioning profited the most.
On presence and relationship quality, risk‐status did not moderate youth outcomes.
Background
SARS‐CoV‐2 coronavirus infection ranges from asymptomatic through to fatal COVID‐19 characterized by a ‘cytokine storm’ and lung failure. Vitamin D deficiency has been postulated as a ...determinant of severity.
Objectives
To review the evidence relevant to vitamin D and COVID‐19.
Methods
Narrative review.
Results
Regression modelling shows that more northerly countries in the Northern Hemisphere are currently (May 2020) showing relatively high COVID‐19 mortality, with an estimated 4.4% increase in mortality for each 1 degree latitude north of 28 degrees North (P = 0.031) after adjustment for age of population. This supports a role for ultraviolet B acting via vitamin D synthesis. Factors associated with worse COVID‐19 prognosis include old age, ethnicity, male sex, obesity, diabetes and hypertension and these also associate with deficiency of vitamin D or its response. Vitamin D deficiency is also linked to severity of childhood respiratory illness. Experimentally, vitamin D increases the ratio of angiotensin‐converting enzyme 2 (ACE2) to ACE, thus increasing angiotensin II hydrolysis and reducing subsequent inflammatory cytokine response to pathogens and lung injury.
Conclusions
Substantial evidence supports a link between vitamin D deficiency and COVID‐19 severity but it is all indirect. Community‐based placebo‐controlled trials of vitamin D supplementation may be difficult. Further evidence could come from study of COVID‐19 outcomes in large cohorts with information on prescribing data for vitamin D supplementation or assay of serum unbound 25(OH) vitamin D levels. Meanwhile, vitamin D supplementation should be strongly advised for people likely to be deficient.
ABSTRACT
We present high-cadence multifrequency radio observations of the long gamma-ray burst (GRB) 190829A, which was detected at photon energies above 100 GeV by the High Energy Stereoscopic ...System (H.E.S.S.). Observations with the Meer Karoo Array Telescope (MeerKAT, 1.3 GHz) and Arcminute Microkelvin Imager – Large Array (AMI-LA, 15.5 GHz) began one day post-burst and lasted nearly 200 d. We used complementary data from Swift X-Ray Telescope (XRT), which ran to 100 d post-burst. We detected a likely forward shock component with both MeerKAT and XRT up to over 100 d post-burst. Conversely, the AMI-LA light curve appears to be dominated by reverse shock emission until around 70 d post-burst when the afterglow flux drops below the level of the host galaxy. We also present previously unpublished observations of the other H.E.S.S.-detected GRB, GRB 180720B from AMI-LA, which shows likely forward shock emission that fades in less than 10 d. We present a comparison between the radio emission from the three GRBs with detected very high energy (VHE) gamma-ray emission and a sensitivity-limited radio afterglow sample. GRB 190829A has the lowest isotropic radio luminosity of any GRB in our sample, but the distribution of luminosities is otherwise consistent, as expected, with the VHE GRBs being drawn from the same parent distribution as the other radio-detected long GRBs.
Summary
Background
The therapeutic effect of enteral nutrition in Crohn's disease (CD) and the epidemiological associations between diet and inflammatory bowel disease (IBD) implicate diet in IBD ...causation. There is little evidence, however, to support specific dietary changes and patients often receive contradictory advice.
Aim
To review the literature on the impacts of diet on IBD causation and activity to produce guidance based on ‘best available evidence’.
Method
Review of Medline, Embase and Cochrane databases from 1975 to 2012 using MeSH headings ‘crohn's disease’ ‘ulcerative colitis’ ‘enteral’ ‘diet’ ‘nutrition’ ‘fatty acid’ and ‘food additives’.
Results
Enteral nutrition with a formula‐defined feed is effective treatment for CD, but approximately 50% of patients relapse within 6 months of return to normal diet. There is no direct evidence of benefit from any other specific dietary modification in CD, but indirect evidence supports recommendation of a low intake of animal fat, insoluble fibre and processed fatty foods containing emulsifiers. Foods tolerated in sustained remission may not be tolerated following relapse. Some evidence supports vitamin D supplementation. In ulcerative colitis (UC), evidence is weaker, but high intakes of meat and margarine correlate with increased UC incidence and high meat intake also correlates with increased likelihood of relapse.
Conclusions
There is little evidence from interventional studies to support specific dietary recommendations. Nevertheless, people with IBD deserve advice based on ‘best available evidence’ rather than no advice at all, although dietary intake should not be inappropriately restrictive. Further interventional studies of dietary manipulation are urgently required.
Although the main Raman features of semiconducting transition metal dichalcogenides are well known for the monolayer and bulk, there are important differences exhibited by few layered systems which ...have not been fully addressed. WSe2 samples were synthesized and ab-initio calculations carried out. We calculated phonon dispersions and Raman-active modes in layered systems: WSe2, MoSe2, WS2 and MoS2 ranging from monolayers to five-layers and the bulk. First, we confirmed that as the number of layers increase, the E', E″ and E2g modes shift to lower frequencies, and the A'1 and A1g modes shift to higher frequencies. Second, new high frequency first order A'1 and A1g modes appear, explaining recently reported experimental data for WSe2, MoSe2 and MoS2. Third, splitting of modes around A'1 and A1g is found which explains those observed in MoSe2. Finally, exterior and interior layers possess different vibrational frequencies. Therefore, it is now possible to precisely identify few-layered STMD.
We present Advanced Camera for Surveys, NICMOS, and Keck adaptive-optics-assisted photometry of 20 Type Ia supernovae (SNe Ia) from the Hubble Space Telescope (HST) Cluster Supernova Survey. The SNe ...Ia were discovered over the redshift interval 0.623 < z < 1.415. Of these SNe Ia, 14 pass our strict selection cuts and are used in combination with the world's sample of SNe Ia to derive the best current constraints on dark energy. Of our new SNe Ia, 10 are beyond redshift z = 1, thereby nearly doubling the statistical weight of HST-discovered SNe Ia beyond this redshift. Our detailed analysis corrects for the recently identified correlation between SN Ia luminosity and host galaxy mass and corrects the NICMOS zero point at the count rates appropriate for very distant SNe Ia. Adding these SNe improves the best combined constraint on dark-energy density, rho sub(DE)(z), at redshifts 1.0 < z < 1.6 by 18% (including systematic errors). For a flat LAMBDACDM universe, we find ohm sub(Lambda) = 0.729 + or - 0.014 (68% confidence level (CL) including systematic errors). For a flat wCDM model, we measure a constant dark-energy equation-of-state parameter w = -1.013 super(+0.068) sub(-0.073) (68% CL). Curvature is constrained to ~0.7% in the owCDM model and to 2% in a model in which dark energy is allowed to vary with parameters w sub(0) and w sub(a). Further tightening the constraints on the time evolution of dark energy will require several improvements, including high-quality multi-passband photometry of a sample of several dozen z > 1 SNe Ia. We describe how such a sample could be efficiently obtained by targeting cluster fields with WFC3 on board HST. The updated supernova Union2.1 compilation of 580 SNe is available at http://supernova.lbl.gov/Union.
Abstract
We present ultraviolet (UV), optical and infrared photometry and optical spectroscopy of the type Ic superluminous supernova (SLSN) Gaia16apd (=SN 2016eay), covering its evolution from 26 d ...before the g-band peak to 234.1 d after the peak. Gaia16apd was followed as a part of the NOT Unbiased Transient Survey (NUTS). It is one of the closest SLSNe known (z = 0.102 ± 0.001), with detailed optical and UV observations covering the peak. Gaia16apd is a spectroscopically typical type Ic SLSN, exhibiting the characteristic blue early spectra with O ii absorption, and reaches a peak Mg = −21.8 ± 0.1 mag. However, photometrically it exhibits an evolution intermediate between the fast and slowly declining type Ic SLSNe, with an early evolution closer to the fast-declining events. Together with LSQ12dlf, another SLSN with similar properties, it demonstrates a possible continuum between fast and slowly declining events. It is unusually UV-bright even for an SLSN, reaching a non-K-corrected Muvm2 ≃ −23.3 mag, the only other type Ic SLSN with similar UV brightness being SN 2010gx. Assuming that Gaia16apd was powered by magnetar spin-down, we derive a period of P = 1.9 ± 0.2 ms and a magnetic field of B = 1.9 ± 0.2 × 1014 G for the magnetar. The estimated ejecta mass is between 8 and 16 M⊙, and the kinetic energy between 1.3 and 2.5 × 1052 erg, depending on opacity and assuming that the entire ejecta is swept up into a thin shell. Despite the early photometric differences, the spectra at late times are similar to slowly declining type Ic SLSNe, implying that the two subclasses originate from similar progenitors.
We pooled data from 5 large validation studies (1999-2009) of dietary self-report instruments that used recovery biomarkers as referents, to assess food frequency questionnaires (FFQs) and 24-hour ...recalls (24HRs). Here we report on total potassium and sodium intakes, their densities, and their ratio. Results were similar by sex but were heterogeneous across studies. For potassium, potassium density, sodium, sodium density, and sodium:potassium ratio, average correlation coefficients for the correlation of reported intake with true intake on the FFQs were 0.37, 0.47, 0.16, 0.32, and 0.49, respectively. For the same nutrients measured with a single 24HR, they were 0.47, 0.46, 0.32, 0.31, and 0.46, respectively, rising to 0.56, 0.53, 0.41, 0.38, and 0.60 for the average of three 24HRs. Average underreporting was 5%-6% with an FFQ and 0%-4% with a single 24HR for potassium but was 28%-39% and 4%-13%, respectively, for sodium. Higher body mass index was related to underreporting of sodium. Calibration equations for true intake that included personal characteristics provided improved prediction, except for sodium density. In summary, self-reports capture potassium intake quite well but sodium intake less well. Using densities improves the measurement of potassium and sodium on an FFQ. Sodium:potassium ratio is measured much better than sodium itself on both FFQs and 24HRs.
Summary
Background
Approximately one third of patients with acute severe ulcerative colitis (ASUC) fail response to steroids. Ciclosporin and anti‐TNFα are proven second‐line therapies, but evidence ...of their efficacy has come mainly from tertiary centres and/or selective clinical trial recruitment.
Aim
To assess ASUC outcomes in a large unselected cohort.
Methods
UK‐wide audits of IBD care were conducted in 2008 (209 hospital sites) and 2010 (198 hospital sites), covering >87% of admitting hospitals. Each site entered data from 20 consecutive UC admissions onto a web‐based proforma. Admissions included 852 (2008) and 984 (2010) with ASUC, accounting for 35% and 39% of UC admissions, respectively.
Results
ASUC in‐hospital mortality was 1.2% in 2008; 0.7% in 2010 (P = 0.22). Response to first‐line steroid therapy was 61% (2008); 58% (2010) and mortality was higher in non‐responders: 2008: 2.9% (9/315) vs. 0.19% (1/537; P < 0.001); 2010: 1.8% (7/391) vs. 0.0% (0/593; P = 0.002). In 2010, more patients (56%) received second‐line medical therapy than in 2008 (47%, P = 0.02). In‐hospital mortality was similar to second‐line medical therapy vs. surgery without further medical therapy; 2008: 2.7% vs. 2.8%, P = 0.99; 2010: 0.9% vs. 3.1%, P = 0.17. Second‐line therapy response was more frequently observed with anti‐TNFα than ciclosporin: (2008: 76% vs. 46%, P < 0.001; 2010: 80% vs. 58%, P < 0.001).
Conclusions
Mortality in acute severe ulcerative colitis was low, but higher in steroid non‐responders. Patients treated with second‐line medical therapies had no higher risk of in‐hospital mortality than those undergoing surgery. Second‐line ‘rescue’ medical therapy usage is increasing; however, ciclosporin response rates were relatively low.
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