3,437 research outputs found

    Present-Day Descendants of z=3 Ly-{\alpha} Emitting Galaxies in the Millennium-II Halo Merger Trees

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    Using the Millennium-II Simulation dark matter sub-halo merger histories, we created mock catalogs of Lyman Alpha Emitting (LAE) galaxies at z=3.1 to study the properties of their descendants. Several models were created by selecting the sub-halos to match the number density and typical dark matter mass determined from observations of these galaxies. We used mass-based and age-based selection criteria to study their effects on descendant populations at z~2, 1 and 0. For the models that best represent LAEs at z=3.1, the z=0 descendants have a median dark matter halo mass of 10^12.7 M_Sun, with a wide scatter in masses (50% between 10^11.8 and 10^13.7 M_Sun). Our study differentiated between central and satellite sub-halos and found that ~55% of z=0 descendants are central sub-halos with M_Median~10^12 M_Sun. This confirms that central z=0 descendants of z=3.1 LAEs have halo masses typical of L* type galaxies. The satellite sub-halos reside in group/cluster environments with dark matter masses around 10^14 M_Sun. The median descendant mass is robust to various methods of age determination, but it could vary by a factor of 5 due to current observational uncertainties in the clustering of LAEs used to determine their typical z=3.1 dark matter mass.Comment: Accepted for publication in Ap

    The targeted delivery of multicomponent cargos to cancer cells by nanoporous particle-supported lipid bilayers.

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    Encapsulation of drugs within nanocarriers that selectively target malignant cells promises to mitigate side effects of conventional chemotherapy and to enable delivery of the unique drug combinations needed for personalized medicine. To realize this potential, however, targeted nanocarriers must simultaneously overcome multiple challenges, including specificity, stability and a high capacity for disparate cargos. Here we report porous nanoparticle-supported lipid bilayers (protocells) that synergistically combine properties of liposomes and nanoporous particles. Protocells modified with a targeting peptide that binds to human hepatocellular carcinoma exhibit a 10,000-fold greater affinity for human hepatocellular carcinoma than for hepatocytes, endothelial cells or immune cells. Furthermore, protocells can be loaded with combinations of therapeutic (drugs, small interfering RNA and toxins) and diagnostic (quantum dots) agents and modified to promote endosomal escape and nuclear accumulation of selected cargos. The enormous capacity of the high-surface-area nanoporous core combined with the enhanced targeting efficacy enabled by the fluid supported lipid bilayer enable a single protocell loaded with a drug cocktail to kill a drug-resistant human hepatocellular carcinoma cell, representing a 10(6)-fold improvement over comparable liposomes

    Are sexual media exposure, parental restrictions on media use and co-viewing TV and DVDs with parents and friends associated with teenagers' early sexual behaviour?

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    Sexual content in teenagers' media diets is known to predict early sexual behaviour. Research on sexual content has not allowed for the social context of media use, which may affect selection and processing of content. This study investigated whether sexual media content and/or contextual factors (co-viewing, parental media restrictions) were associated with early sexual behaviour using 2251 14–15 year-olds from Scotland, UK. A third (<i>n</i> = 733) reported sexual intercourse. In multivariable analysis the likelihood of intercourse was lower with parental restriction of sexual media and same-sex peer co-viewing; but higher with mixed-sex peer co-viewing. Parental co-viewing, other parental restrictions on media and sexual film content exposure were not associated with intercourse. Findings suggest the context of media use may influence early sexual behaviour. Specific parental restrictions on sexual media may offer more protection against early sex than other restrictions or parental co-viewing. Further research is required to establish causal mechanisms

    Psychosocial Factors Associated with Patterns of Smoking Surrounding Pregnancy in Fragile Families

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    Although research has documented factors associated with maternal smoking, we need a more in-depth understanding of the risk factors associated with changes in smoking behaviors during the postpartum period. We investigate smoking patterns during pregnancy and 1 year postpartum as a function of relevant psychosocial factors. We use data on 3,522 postpartum mothers from the Fragile Families and Child Wellbeing Study to analyze the predictors of smoking among mothers who did not smoke during pregnancy but smoked at 1 year postpartum, mothers who smoked both during pregnancy and postpartum, and mothers who did not smoke during either period. Our covariates are grouped into four categories of risk factors for smoking: socioeconomic status, health care, life course and health, and partner and social support. Postpartum mothers in our sample were more likely to smoke throughout or after their pregnancies if they had only a high school education or less, had a household income three or more times below the poverty line, had public or no health insurance, breastfed for less than 5 months, were not married to the infant’s father, if the infant’s father currently smoked, and if they attended religious services less than once a week. Mental health problems were consistently associated with an increased risk of constant and postpartum smoking relative to non-smoking. Psychosocial factors play a role in postpartum smoking, but they have a stronger effect in predicting smoking that persists throughout pregnancy and the first year postpartum

    Milagro Constraints on Very High Energy Emission from Short Duration Gamma-Ray Bursts

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    Recent rapid localizations of short, hard gamma-ray bursts (GRBs) by the Swift and HETE satellites have led to the observation of the first afterglows and the measurement of the first redshifts from this type of burst. Detection of >100 GeV counterparts would place powerful constraints on GRB mechanisms. Seventeen short duration (< 5 s) GRBs detected by satellites occurred within the field of view of the Milagro gamma-ray observatory between 2000 January and 2006 December. We have searched the Milagro data for >100 GeV counterparts to these GRBs and find no significant emission correlated with these bursts. Due to the absorption of high-energy gamma rays by the extragalactic background light (EBL), detections are only expected for redshifts less than ~0.5. While most long duration GRBs occur at redshifts higher than 0.5, the opposite is thought to be true of short GRBs. Lack of a detected VHE signal thus allows setting meaningful fluence limits. One GRB in the sample (050509b) has a likely association with a galaxy at a redshift of 0.225, while another (051103) has been tentatively linked to the nearby galaxy M81. Fluence limits are corrected for EBL absorption, either using the known measured redshift, or computing the corresponding absorption for a redshift of 0.1 and 0.5, as well as for the case of z=0.Comment: Accepted for publication in the Astrophysical Journa

    Calidad de Vida: a systematic review of quality of life in Latino cancer survivors in the USA

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    Background: Cancer is the leading cause of death among Hispanics/Latinos. Thus, understanding health-related quality of life (HRQOL) needs among this diverse racial/ethnic group is critical. Using Ferrell’s multidimensional framework for measuring QOL, we synthesized evidence on HRQOL needs among Hispanic/Latino cancer survivors. Methods: We searched MEDLINE/PubMed, EMBASE, CINAHL, and PsycINFO, for English language articles published between 1995 and January 2020, reporting HRQOL among Hispanic/Latino cancer survivors in the USA. Results: Of the 648 articles reviewed, 176 met inclusion criteria, with 100 of these studies focusing exclusively on breast cancer patients and no studies examining end-of-life HRQOL issues. Compared with other racial/ethnic groups, Hispanics/Latinos reported lower HRQOL and a higher symptom burden across multiple HRQOL domains. Over 80% of studies examining racial/ethnic differences in psychological well-being (n = 45) reported worse outcomes among Hispanics/Latinos compared with other racial/ethnic groups. Hispanic/Latino cancer survivors were also more likely to report suboptimal physical well-being in 60% of studies assessing racial/ethnic differences (n = 27), and Hispanics/Latinos also reported lower social well-being relative to non-Hispanics/Latinos in 78% of studies reporting these outcomes (n = 32). In contrast, reports of spiritual well-being and spirituality-based coping were higher among Hispanics/Latinos cancer survivors in 50% of studies examining racial/ethnic differences (n = 15). Discussion: Findings from this review point to the need for more systematic and tailored interventions to address HRQOL needs among this growing cancer survivor population. Future HRQOL research on Hispanics/Latinos should evaluate variations in HRQOL needs across cancer types and Hispanic/Latino subgroups and assess HRQOL needs during metastatic and end-of-life disease phases

    Follow-up observations at 16 and 33 GHz of extragalactic sources from WMAP 3-year data: I - Spectral properties

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    We present follow-up observations of 97 point sources from the Wilkinson Microwave Anisotropy Probe (WMAP) 3-year data, contained within the New Extragalactic WMAP Point Source (NEWPS) catalogue between declinations of -4 and +60 degrees; the sources form a flux-density-limited sample complete to 1.1 Jy (approximately 5 sigma) at 33 GHz. Our observations were made at 16 GHz using the Arcminute Microkelvin Imager (AMI) and at 33 GHz with the Very Small Array (VSA). 94 of the sources have reliable, simultaneous -- typically a few minutes apart -- observations with both telescopes. The spectra between 13.9 and 33.75 GHz are very different from those of bright sources at low frequency: 44 per cent have rising spectra (alpha < 0.0), where flux density is proportional to frequency^-alpha, and 93 per cent have spectra with alpha < 0.5; the median spectral index is 0.04. For the brighter sources, the agreement between VSA and WMAP 33-GHz flux densities averaged over sources is very good. However, for the fainter sources, the VSA tends to measure lower values for the flux densities than WMAP. We suggest that the main cause of this effect is Eddington bias arising from variability.Comment: 12 pages, 13 figures, submitted to MNRA

    Structural properties of disk galaxies. II. Intrinsic shape of bulges

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    (Abridged) The structural parameters of a magnitude-limited sample of 148 unbarred S0-Sb galaxies were analyzed to derive the intrinsic shape of their bulges. We developed a new method to derive the intrinsic shape of bulges based on the geometrical relationships between the apparent and intrinsic shapes of bulges and disks. The equatorial ellipticity and intrinsic flattening of bulges were obtained from the length of the apparent major and minor semi-axes of the bulge, twist angle between the apparent major axis of the bulge and the galaxy line of nodes, and galaxy inclination. We found that the intrinsic shape is well constrained for a subsample of 115 bulges with favorable viewing angles. A large fraction of them is characterized by an elliptical section (B/A<0.9). This fraction is 33%, 55%, and 43% if using their maximum, mean, or median equatorial ellipticity, respectively. Most are flattened along their polar axis (C<(A+B)/2). The distribution of triaxiality is strongly bimodal. This bimodality is driven by bulges with Sersic index n>2, or equivalently, by the bulges of galaxies with a bulge-to-total ratio B/T>0.3. In particular, bulges with n\leq2 and with B/T\leq0.3 show a larger fraction of oblate axisymmetric (or nearly axisymmetric) bulges, a smaller fraction of triaxial bulges, and fewer prolate axisymmetric (or nearly axisymmetric) bulges with respect to bulges with n>2 and with B/T>0.3, respectively. According to predictions of the numerical simulations of bulge formation, bulges with n\leq2, which show a high fraction of oblate axisymmetric (or nearly axisymmetric) shapes and have B/T\leq0.3, could be the result of dissipational minor mergers. Both major dissipational and dissipationless mergers seem to be required to explain the variety of shapes found for bulges with n>2 and B/T>0.3.Comment: 16 pages, 12 figures; accepted for publication in A&

    Parent-Child Value Similarity in Families with Young Children: The Predictive Power of Prosocial Educational Goals

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    Value transmission from one generation to the next is a key issue in every society, but it is not clear which parents are the most successful in transmitting their values to their children. We propose parents’ prosocial educational goals as key predictors of parent-child value similarity and accordingly hypothesized that the more parents wanted their children to endorse values of self-transcendence (helping, supporting, and caring for others) and the less parents wanted their children to endorse the opposing values of self-enhancement (striving for power and achievement), the higher would be parent-child overall value similarity. Findings from two studies of families – Study 1: 261 Swiss families, children aged 7-9 years; Study 2: 157 German families, children aged 6-11 years – confirmed this hypothesis. The effect was even stronger after controlling for values that prevail in the Swiss and German society, respectively. We integrate evidence from this study of values in families with young children with existing findings from studies with adolescent and adult children, and we discuss potential pathways from parents’ educational goals to parent-child value similarity
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