On the formation of low-mass black holes in massive binary stars

Recently (Brown \& Bethe 1994) it was suggested that most stars with main sequence mass in the range of about $18 - 30 M_{\odot}$ explode, returning matter to the Galaxy, and then go into low-mass ($\geq 1.5 M_{\odot}$) black holes. Even more massive main-sequence stars would, presumably, chiefly g o into high-mass ($\sim 10 M_{\odot}$) black holes. The Brown-Bethe estimates gave approximately $5 \times {10}^{8}$ low-mass black holes in the Galaxy. A pressing question, which we attempt to answer here, is why, with the possible exception of the compact objects in SN1987A and 4U\,1700--37, none of these have been seen. We address this question in three parts. Firstly, black holes are generally ``seen'' only in binaries, by the accretion of matter from a companion star. High mass black holes are capable of accreting more matter than low-mass black holes, so there is a selection effect favoring them. This, in itself, would not be sufficient to show why low-mass black holes have not been seen, since neutron stars (of nearly the same mass) are seen in abundance. Secondly, and this is our main point, the primary star in a binary ---the first star to evolve--- loses its hydrogen envelope by transfer of matter to the secondary and loss into space, and the resulting ``naked'' helium star evolves differently than a helium core, which is at least initially covered by the hydrogen envelope in a massive main-sequence star. We show that primary stars in binaries can end up as neutron stars even if their initial mass substantially exceeds the mass limit for neutron star formation from single stars ($\sim 18 M_{\odot}$). An example is 4U\,1223--62, in which we suggest that the initial primary mass exceeded $35 M_{\odot}$, yet X-ray pulsationsComment: uuencoded compressed postscript. The preprint is also available at http://www.ast.cam.ac.uk/preprint/PrePrint.htm

Sex radicals in America's heartland : redefining gender and sexuality, 1880-1910

This study examines the rise of sex radicalism in Kansas and the larger Midwest as men and women sought to redefine the ways in which they thought about gender and sexuality. Specifically, it follows the career of Moses Harman, his journal Lucifer, the Light-Bearer, and the conversation of its many correspondents. Sex radicals based their ideas of free love on the tradition of American freethought and were rooted in the class struggle that marked the economic inequalities of the gilded age. While previous studies of free love consider the way in which the movement empowered women, a complete gendered analysis is lacking in the historiography. Examining the movement's male leaders, I argue that free love served to empower men at a time when they were experiencing a crisis in their own male identities. Through the promotion of women's emancipation from "sex slavery" and the abolishment of marriage, sex radical men sought to throw off church and state oppression, defend against gilded-age capitalism, and recreate a form of individualism that they believed had been lost since the early nineteenth century. In making these arguments, I address several key aspects of the movement that have not received adequate attention, including manhood and masculinity, class dynamics, freethought, eugenics, and the region of the Midwestern United States. Only a thorough investigation of all these factors together can bring a complete gendered analysis of the free love movement and the men and women who were involved in it.Includes bibliographical references (pages 253-262)

Differential effects on inhibition of cholesterol absorption by plant stanol and plant sterol esters in apoE−/− mice

Aims 'Functional foods'; supplemented with plant sterol esters (PSE) and plant stanol esters (PSA) are therapeutic options for the management of hypercholesterolaemia. However, their effects on blood monocytes, endothelial function, atherogenesis, and sterol tissue concentrations are poorly understood. Methods and results Male apoE−/− mice (n= 30) were randomized to three different diets for 6 weeks (n= 10 per group): high-cholesterol (1.25%) western-type diet (WTD), WTD + 2% PSE, and WTD + 2% PSA. Both supplements reduced serum cholesterol. WTD + PSE resulted in increased plant sterol serum concentrations and increased inflammatory Ly-6C(high) monocyte numbers. WTD + PSA increased plant stanol serum concentrations and Ly-6C-monocyte numbers, but decreased vascular superoxide release, lipid hydroperoxides, and inflammatory cytokines in aortic tissue, in plasma, and in circulating monocytes. Despite reduced serum cholesterol concentrations, both supplements impaired endothelial vasodilation compared with WTD. WTD + PSA reduced the development of atherosclerotic lesions compared with WTD alone (12.7 ± 3.7 vs. 28.3 ± 3.5%), and WTD + PSE was less effective (17.5 ± 3.7%). WTD + PSE and WTD + PSA reduced the cholesterol content in the liver, but not in the brain. However, WTD + PSE and WTD + PSA increased plant sterol and plant stanol concentrations in the liver as well as in the brain. Conclusion PSE and PSA supplementation reduced serum cholesterol, but increased plant sterol and plant stanol concentrations. Elevated levels of PSE and PSA were associated with endothelial dysfunction and increased central nervous system depositions. Atherosclerotic lesion retardation was more pronounced in WTD + PSA, coinciding with higher regenerative monocyte numbers, decreased oxidative stress, and decreased inflammatory cytokines compared with WTD + PSE

The Chemistry of Interstellar OH+, H2O+, and H3O+: Inferring the Cosmic Ray Ionization Rates from Observations of Molecular Ions

We model the production of OH+, H2O+, and H3O+ in interstellar clouds, using a steady state photodissociation region code that treats the freeze-out of gas species, grain surface chemistry, and desorption of ices from grains. The code includes PAHs, which have important effects on the chemistry. All three ions generally have two peaks in abundance as a function of depth into the cloud, one at A_V<~1 and one at A_V~3-8, the exact values depending on the ratio of incident ultraviolet flux to gas density. For relatively low values of the incident far ultraviolet flux on the cloud ({\chi}<~ 1000; {\chi}= 1= local interstellar value), the columns of OH+ and H2O+ scale roughly as the cosmic ray primary ionization rate {\zeta}(crp) divided by the hydrogen nucleus density n. The H3O+ column is dominated by the second peak, and we show that if PAHs are present, N(H3O+) ~ 4x10^{13} cm^{-2} independent of {\zeta}(crp) or n. If there are no PAHs or very small grains at the second peak, N(H3O+) can attain such columns only if low ionization potential metals are heavily depleted. We also model diffuse and translucent clouds in the interstellar medium, and show how observations of N(OH+)/N(H) and N(OH+)/N(H2O+) can be used to estimate {\zeta}(crp)/n, {\chi}/n and A_V in them. We compare our models to Herschel observations of these two ions, and estimate {\zeta}(crp) ~ 4-6 x 10^-16 (n/100 cm^-3) s^-1 and \chi/n = 0.03 cm^3 for diffuse foreground clouds towards W49N

13-month climatology of the aerosol hygroscopicity at the free tropospheric site Jungfraujoch (3580 m a.s.l.)

A hygroscopicity tandem differential mobility analyzer (HTDMA) was operated at the high-alpine site Jungfraujoch in order to characterize the hygroscopic diameter growth factors of the free tropospheric Aitken and accumulation mode aerosol. More than ~5000 h of valid data were collected for the dry diameters &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;0&lt;/sub&gt; = 35, 50, 75, 110, 165, and 265 nm during the 13-month measurement period from 1 May 2008 through 31 May 2009. No distinct seasonal variability of the hygroscopic properties was observed. Annual mean hygroscopic diameter growth factors (&lt;i&gt;D&lt;/i&gt;/&lt;i&gt;D&lt;/i&gt;&lt;sub&gt;0&lt;/sub&gt;) at 90% relative humidity were found to be 1.34, 1.43, and 1.46 for &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;0&lt;/sub&gt; = 50, 110, and 265 nm, respectively. This size dependence can largely be attributed to the Kelvin effect because corresponding values of the hygroscopicity parameter κ are nearly independent of size. The mean hygroscopicity of the Aitken and accumulation mode aerosol at the free tropospheric site Jungfraujoch was found to be &amp;kappa;≈0.24 with little variability throughout the year. &lt;br&gt;&lt;br&gt; The impact of Saharan dust events, a frequent phenomenon at the Jungfraujoch, on aerosol hygroscopicity was shown to be negligible for &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;0&lt;/sub&gt;&lt;265 nm. Thermally driven injections of planetary boundary layer (PBL) air, particularly observed in the early afternoon of summer days with convective anticyclonic weather conditions, lead to a decrease of aerosol hygroscopicity. However, the effect of PBL influence is not seen in the annual mean hygroscopicity data because the effect is small and those conditions (weather class, season and time of day) with PBL influence are relatively rare. &lt;br&gt;&lt;br&gt; Aerosol hygroscopicity was found to be virtually independent of synoptic wind direction during advective weather situations, i.e. when horizontal motion of the atmosphere dominates over thermally driven convection. This indicates that the hygroscopic behavior of the aerosol observed at the Jungfraujoch can be considered representative of the lower free troposphere on at least a regional if not continental scale

Comparing Medical Student Nonverbal Behavior With Cisgender And Transgender Standardized Patients

It is essential for medical students to effectively communicate with patients of all gender identities. Evaluating nonverbal behavior is one way to assess the quality of patient care – examining providers’ behaviors while working with cisgender and transgender patients can identify potential biases linked to patient identity. To evaluate nonverbal behavior, the authors analyzed video-recorded training sessions with medical students interviewing standardized patients who identified as cisgender or transgender women. All students identified as cisgender men or cisgender women. The authors rated ten nonverbal behaviors from 1-7 and noted whether these behaviors were perceived to detract from the encounter. Average scores for nonverbal behaviors were similar between students working with cisgender and transgender patients. Nodding frequency showed the largest difference between cisgender (m = 5.65) and transgender (m = 4.93) patients. When considering student gender identity, cisgender men had lower facial expressivity and smiling frequency scores on average but higher scores for unnecessary silence compared to cisgender women across encounters. Detracting behaviors that negatively impacted the patient encounters were most likely to be self-touching/unpurposive movements (41%) and unnecessary silences (26%). Among the students, cisgender men demonstrated detracting behaviors at a higher rate than cisgender women. The consistency in nonverbal behavior during encounters with cisgender and transgender patients is encouraging. It is possible that LGBTQ health training in medical education contributed to this outcome; however, differences in verbal communication could contribute more to health disparities for transgender patients. Additional practice with unpurposive movements and unnecessary silences could improve nonverbal communication skills

Perspectives on Interstellar Dust Inside and Outside of the Heliosphere

Measurements by dust detectors on interplanetary spacecraft appear to indicate a substantial flux of interstellar particles with masses exceeding 10^{-12}gram. The reported abundance of these massive grains cannot be typical of interstellar gas: it is incompatible with both interstellar elemental abundances and the observed extinction properties of the interstellar dust population. We discuss the likelihood that the Solar System is by chance located near an unusual concentration of massive grains and conclude that this is unlikely, unless dynamical processes in the ISM are responsible for such concentrations. Radiation pressure might conceivably drive large grains into "magnetic valleys". If the influx direction of interstellar gas and dust is varying on a ~10 yr timescale, as suggested by some observations, this would have dramatic implications for the small-scale structure of the interstellar medium.Comment: 13 pages. To appear in Space Science Review

Gender Identity and Pronoun Usage in Standardized Patient Encounters

The standardized documentation clinicians use to record evaluations of a patient are called Subjective, Objective, Assessment, and Plan (SOAP) notes. Consistent pronoun documentation and usage in these notes is especially important for affirming transgender and gender non-conforming patients as this population experiences significant health disparities linked to medical mistrust. A sample of SOAP notes (n=286) was taken from standardized patient encounters at the University of Louisville School of Medicine in 2017 (n=137) and 2018 (n=149). There were five case iterations of the standardized patient based on gender identity. The notes were coded using the software Dedoose for the following themes: pronouns clearly established, consistent pronoun usage, no pronoun usage, and disregard for established pronouns. Pronouns were clearly established in only 27.27% of the notes (n=78/286). Non-cisgender patients were more likely to have pronouns that were clearly established (41% vs 5%). Consistent pronoun usage was most often observed among the notes of cisgender patients. Inconsistent pronoun usage and disregard for established pronouns was observed most often for genderqueer patients (16%, n=14). Complete absence of pronoun use occurred in the notes of trans women (7%, n=3), genderqueer patients (8%, n=7), and cisgender women (3%, n=2) patients. These notes demonstrate a lack of rigor in recording pronouns accurately and consistently for patients, which can be profoundly detrimental to non-cisgender patient care. These discrepancies can be remedied by including training about gender-affirming care and interacting with non-cisgender patients in the clinical skills curriculum