7,846 research outputs found

    Future CMB tests of dark matter: ultra-light axions and massive neutrinos

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    Measurements of cosmic microwave background (CMB) anisotropies provide strong evidence for the existence of dark matter and dark energy. They can also test its composition, probing the energy density and particle mass of different dark-matter and dark-energy components. CMB data have already shown that ultra-light axions (ULAs) with mass in the range 1032 eV1026 eV10^{-32}~{\rm eV} \to 10^{-26}~{\rm eV} compose a fraction <0.01< 0.01 of the cosmological critical density. Here, the sensitivity of a proposed CMB-Stage IV (CMB-S4) experiment (assuming a 1 arcmin beam and <1 μKarcmin< 1~\mu K{\rm-arcmin} noise levels over a sky fraction of 0.4) to the density of ULAs and other dark-sector components is assessed. CMB-S4 data should be 10\sim 10 times more sensitive to the ULA energy-density than Planck data alone, across a wide range of ULA masses 1032<ma<1023 eV10^{-32}< m_{a}< 10^{-23}~{\rm eV}, and will probe axion decay constants of fa1016 GeVf_{a}\approx 10^{16}~{\rm GeV}, at the grand unified scale. CMB-S4 could improve the CMB lower bound on the ULA mass from 1025 eV\sim 10^{-25}~{\rm eV} to 1023 eV10^{-23}~{\rm eV}, nearing the mass range probed by dwarf galaxy abundances and dark-matter halo density profiles. These improvements will allow for a multi-σ\sigma detection of percent-level departures from CDM over a wide range of masses. Much of this improvement is driven by the effects of weak gravitational lensing on the CMB, which breaks degeneracies between ULAs and neutrinos. We also find that the addition of ULA parameters does not significantly degrade the sensitivity of the CMB to neutrino masses. These results were obtained using the axionCAMB code (a modification to the CAMB Boltzmann code), presented here for public use.Comment: 16 pages, 12 figures. The axionCAMB code will be available online at http://github.com/dgrin1/axionCAMB from 1 August 201

    Cognitive vulnerability to anxiety: A review and an integrative model.

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    Consistent research evidence supports the existence of threat-relevant cognitive bias in anxiety, but there remains controversy about which stages of information processing are most important in the conferral of cognitive vulnerability to anxiety. To account for both theoretical and empirical discrepancies in the literature, an integrative multi-process model is proposed wherein core assumptions of dual-systems theories from social and cognitive psychology are adapted to explain attentional and interpretive biases in the anxiety disorders. According to the model, individual differences in associative and rule-based processing jointly influence orientation, engagement, disengagement, and avoidance of threat-relevant stimuli, as well as negatively-biased interpretation of ambiguous stimuli in anxious populations. By linking anxiety-related symptoms to basic principles of information processing, the model parsimoniously integrates different kinds of cognitive biases in anxiety, providing a useful framework for future research and clinical intervention

    Intergenerational Transmission of Reproductive Behavior during the Demographic Transition

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    New evidence from the Utah Population Database (updp) reveals that at the onset of the fertility transition, reproductive behavior was transmitted across generations—between women and their mothers, as well as between women and their husbands\u27 family of origin. Age at marriage, age at last birth, and the number of children ever born are positively correlated in the data, most strongly among first-born daughters and among cohorts born later in the fertility transition. Intergenerational ties, including the presence of mothers and mothers-in-law, influenced the hazard of progressing to a next birth. The findings suggest that the practice of parity-dependent marital fertility control and inter-birth spacing behavior derived, in part, from the previous generation and that the potential for mothers and mothers-in-law to help in the rearing of children encouraged higher marital fertility

    Uncertainty Monitoring by Young Children in a Computerized Task

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    Adult humans show sophisticated metacognitive abilities, including the ability to monitor uncertainty. Unfortunately, most measures of uncertainty monitoring are limited to use with adults due to their general complexity and dependence on explicit verbalization. However, recent research with nonhuman animals has successfully developed measures of uncertainty monitoring that are simple and do not require explicit verbalization. The purpose of this study was to investigate metacognition in young children using uncertainty monitoring tests developed for nonhumans. Children judged whether stimuli were more pink or blue—stimuli nearest the pink-blue midpoint were the most uncertain and the most difficult to classify. Children also had an option to acknowledge difficulty and gain the necessary information for correct classification. As predicted, children most often asked for help on the most difficult stimuli. This result confirms that some metacognitive abilities appear early in cognitive development. The tasks of animal metacognition research clearly have substantial utility for exploring the early developmental roots of human metacognition

    Thyroid Diseas in a Peruvian Mummy

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    Although the pathogenesis of endocrine disorders has only recently been recognized, disorders of the thyroid gland have been recorded since ancient times, primarily because of the gland’s strategic location in the neck. Goiter, enlargement of the gland, was described early in history and endocrine goiter was also mentioned. The earliest written references go back as far as the Chinese of the second millennium BC, Greek and Roman authors of classical times, and medieval manuscripts. In his history of goiter, Greenwald contended that there was no evidence of goiter in the Americas before the coming of the white man, although the protruding eyes of possible exophthalmic goiter are seen in Peruvian ceramic sculpture from 2000 years ago

    Impaired Hyperemic Response to Exercise Post Stroke

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    Individuals with chronic stroke have reduced perfusion of the paretic lower limb at rest; however, the hyperemic response to graded muscle contractions in this patient population has not been examined. This study quantified blood flow to the paretic and non-paretic lower limbs of subjects with chronic stroke after submaximal contractions of the knee extensor muscles and correlated those measures with limb function and activity. Ten subjects with chronic stroke and ten controls had blood flow through the superficial femoral artery quantified with ultrasonography before and immediately after 10 second contractions of the knee extensor muscles at 20, 40, 60, and 80% of the maximal voluntary contraction (MVC) of the test limb. Blood flow to the paretic and non-paretic limb of stroke subjects was significantly reduced at all load levels compared to control subjects even after normalization to lean muscle mass. Of variables measured, increased blood flow after an 80% MVC was the single best predictor of paretic limb strength, the symmetry of strength between the paretic and non-paretic limbs, coordination of the paretic limb, and physical activity. The impaired hemodynamic response to high intensity contractions was a better predictor of lower limb function than resting perfusion measures. Stroke-dependent weakness and atrophy of the paretic limb do not explain the reduced hyperemic response to muscle contraction alone as the response is similarly reduced in the non-paretic limb when compared to controls. These data may suggest a role for perfusion therapies to optimize rehabilitation post stroke

    Errors in statistical analysis and questionable randomization lead to unreliable conclusions

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    Dear Editor,We read with interest the paper, “The effect of food service system modifications on staff body mass index in an industrial organization”[1]. We noticed several substantial issues with data and calculations, calling into question the randomized nature of the study and validity of analyses.The distribution of baseline weight was significantly differentbetween groups (p-value = “0.00”). We replicated the test using reported means and standard deviations (SDs) andobtained a p-value of approximately 1.9*10-17. It is extraordinarily unlikely that any variable would be that different between two groups if allocation was truly random. Even it was truly random, the stated method of “the samples were randomly divided into two groups”[1] does not describe the “method used to generate the random allocation sequence” and the “type of randomization; details of any restriction (such as blocking and block size)” details specified by Consolidated Standards of Reporting Trials (CONSORT)[2].Given the large difference in baseline weights, it is unusual that the difference in baseline body mass index (BMI) between groups is not more significant (p=0.032), raising the question of what the groups’ distributions of height were. Both groups have 30 males (58.8%), so sex differences are unlikely to explain this discrepancy. Height was not explicitly reported, but it was possible to estimate height utilizing geometric means from body weight and BMI[3,4]. We calculated the baseline control group geometric mean as 2.04 cm taller than the test group. These calculations also suggest the control group shrunk by 1.26 cm while the test group grew by 1.52 cm over the study. Neither change is explained by rounding error nor seems plausible for adult subjects over 40 days.Because there were no SDs of the change scores reported, we were unable to replicate the reported p-value (0.318) for the between-group test of weight change exactly. However, we were able to consider the pre and post-intervention SDs and calculate possible SDs of within-group change scores for a range of pre-post correlations. The largest p-value possible was 0.1282, calculated when each group had perfect negative pre-post correlation (correlation=-1), which is unlikely. If there was no or a positive correlation, the p-value would be much smaller (p=0.0449 when correlation=0 for each group) and plausibly indicates a significant difference between groups. Therefore, although the published results are impossible the correct analysis could make the intervention appear more effective than reported.The results section describes an initial sample size of 116 with 14 dropping out (p. 115). The tables report the remaining sample size to be 102, but the body of the text reports 101 subjects remained until study completion. It is unclear which values were correct; this lack of clarity also fails CONSORT guidelines[2].Considering that the reported findings are essentially impossible given the stated study design, we encourage the authors to explain the treatment allocationand make the raw data available, or the journal to act according to the Committee on Publication Ethics[5] in situations where findings are unreliabl

    Impact of breast cancer subtypes on 3-year survival among adolescent and young adult women.

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    IntroductionYoung women have poorer survival after breast cancer than do older women. It is unclear whether this survival difference relates to the unique distribution of hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2)-defined molecular breast cancer subtypes among adolescent and young adult (AYA) women aged 15 to 39 years. The purpose of our study was to examine associations between breast cancer subtypes and short-term survival in AYA women, as well as to determine whether the distinct molecular subtype distribution among AYA women explains the unfavorable overall breast cancer survival statistics reported for AYA women compared with older women.MethodsData for 5,331 AYA breast cancers diagnosed between 2005 and 2009 were obtained from the California Cancer Registry. Survival by subtype (triple-negative; HR+/HER2-; HR+/HER2+; HR-/HER2+) and age-group (AYA versus 40- to 64-year-olds) was analyzed with Cox proportional hazards regression with follow-up through 2010.ResultsWith up to 6 years of follow-up and a mean survival time of 3.1 years (SD = 1.5 years), AYA women diagnosed with HR-/HER + and triple-negative breast cancer experienced a 1.6-fold and 2.7-fold increased risk of death, respectively, from all causes (HR-/HER + hazard ratio: 1.55; 95% confidence interval (CI): 1.10 to 2.18; triple-negative HR: 2.75; 95% CI, 2.06 to 3.66) and breast cancer (HR-/HER + hazard ratio: 1.63; 95% CI, 1.12 to 2.36; triple-negative hazard ratio: 2.71; 95% CI, 1.98 to 3.71) than AYA women with HR+/HER2- breast cancer. AYA women who resided in lower socioeconomic status neighborhoods, had public health insurance, and were of Black, compared with White, race/ethnicity experienced worse survival. This race/ethnicity association was attenuated somewhat after adjusting for breast cancer subtypes (hazard ratio, 1.33; 95% CI, 0.98 to 1.82). AYA women had similar all-cause and breast cancer-specific short-term survival as older women for all breast cancer subtypes and across all stages of disease.ConclusionsAmong AYA women with breast cancer, short-term survival varied by breast cancer subtypes, with the distribution of breast cancer subtypes explaining some of the poorer survival observed among Black, compared with White, AYA women. Future studies should consider whether distribution of breast cancer subtypes and other factors, including differential receipt of treatment regimens, influences long-term survival in young compared with older women
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