Characteristics of a New Carbonaceous Chondrite, Metal-Rich-Lithology Found in the Carbonaceous Chondrite Breccia Aguas Zarcas

The Aguas Zarcas meteorite fell in Costa Rica on 23 April 2019 at 21:07 local time, with a total mass of about 27 kg. Hundreds of fusion-crusted stones ranging from 0.1 to 1868 g were recovered (The Meteoritical Bulletin). The meteorite was classified as a CM chondrite, but some lithlogies show a different texture to that of CM. In this study, we investigated the petrography, mineral-ogy, chemistry, and isotopic composition of an unusual Metal-rich-lithology from this fresh fall

On the unconstrained expansion of a spherical plasma cloud turning collisionless : case of a cloud generated by a nanometer dust grain impact on an uncharged target in space

Nano and micro meter sized dust particles travelling through the heliosphere at several hundreds of km/s have been repeatedly detected by interplanetary spacecraft. When such fast moving dust particles hit a solid target in space, an expanding plasma cloud is formed through the vaporisation and ionisation of the dust particles itself and part of the target material at and near the impact point. Immediately after the impact the small and dense cloud is dominated by collisions and the expansion can be described by fluid equations. However, once the cloud has reached micro-m dimensions, the plasma may turn collisionless and a kinetic description is required to describe the subsequent expansion. In this paper we explore the late and possibly collisionless spherically symmetric unconstrained expansion of a single ionized ion-electron plasma using N-body simulations. Given the strong uncertainties concerning the early hydrodynamic expansion, we assume that at the time of the transition to the collisionless regime the cloud density and temperature are spatially uniform. We do also neglect the role of the ambient plasma. This is a reasonable assumption as long as the cloud density is substantially higher than the ambient plasma density. In the case of clouds generated by fast interplanetary dust grains hitting a solid target some 10^7 electrons and ions are liberated and the in vacuum approximation is acceptable up to meter order cloud dimensions. ..

Aging is associated with an earlier arrival of reflected waves without a distal shift in reflection sites

Background-Despite pronounced increases in central pulse wave velocity (PWV) with aging, reflected wave transit time (RWTT), traditionally defined as the timing of the inflection point (T-INF) in the central pressure waveform, does not appreciably decrease, leading to the controversial proposition of a "distal-shift" of reflection sites. T-INF, however, is exceptionally prone to measurement error and is also affected by ejection pattern and not only by wave reflection. We assessed whether RWTT, assessed by advanced pressure-flow analysis, demonstrates the expected decline with aging. Methods and Results-We studied a sample of unselected adults without cardiovascular disease (n=48; median age 48 years) and a clinical population of older adults with suspected/established cardiovascular disease (n=164; 61 years). We measured central pressure and flow with carotid tonometry and phase-contrast MRI, respectively. We assessed RWTT using wave-separation analysis (RWTTWSA) and partially distributed tube-load (TL) modeling (RWTTTL). Consistent with previous reports, T-INF did not appreciably decrease with age despite pronounced increases in PWV in both populations. However, aging was associated with pronounced decreases in RWTTWSA (general population -15.0 ms/decade, P<0.001; clinical population -9.07 ms/decade, P=0.003) and RWTTTL (general -15.8 ms/decade, P<0.001; clinical -11.8 ms/decade, P<0.001). There was no evidence of an increased effective reflecting distance by either method. TINF was shown to reliably represent RWTT only under highly unrealistic assumptions about input impedance. Conclusions-RWTT declines with age in parallel with increased PWV, with earlier effects of wave reflections and without a distal shift in reflecting sites. These findings have important implications for our understanding of the role of wave reflections with aging

GEM Operation in Negative Ion Drift Gas Mixtures

The first operation of GEM gas gain elements in negative ion gas mixtures is reported. Gains up to several thousand were obtained from single-stage GEMs in carbon disulfide vapor at low pressure, and in mixtures of carbon disulfide with Argon and Helium, some near 1 bar total pressure.Comment: 7 pages, 3 figure

Objective Snoring Time and Carotid Intima-Media Thickness in Non-Apneic Female Snorers

Controversy persists about whether snoring can affect atherosclerotic changes in adjacent vessels, independently of obstructive sleep apnea and other cardiovascular risk factors. This study examined the independent association between snoring and carotid artery intima-media thickness (IMT) in non-apneic snorers and non-snorers. We studied 180 non-apneic snorers and non-snorers participating in a full-night home-based sleep study. Snoring sound was measured objectively by a microphone. Based on snoring time across the night, participants were classified as non-snorers (snoring time: 0%), mild snorers (1-25%) and moderate to heavy snorers (≥25%). We measured IMT on both common carotid arteries. The three groups were matched by age, body mass index, cholesterol, blood pressure and glucose levels, using weights from generalized boosted-propensity score models. Mean carotid IMT increased with increased snoring time across the night in women: non-snorers (0.707 mm), mild (0.718 mm) and moderate to heavy snorers (0.774 mm), but not in men. Snoring during at least one-fourth of a night\u27s sleep is associated independently with subclinical changes in carotid IMT in women only

Adam Smith and Colonialism

In the context of debates about liberalism and colonialism, the arguments of Adam Smith have been taken as illustrative of an important line of anti-colonial liberal thought. The reading of Smith presented here challenges this interpretation. It argues that Smith’s opposition to colonial rule derived largely from its impact on the metropole, rather than on its impact on the conquered and colonised; that Smith recognised colonialism had brought ‘improvement’ in conquered territories and that Smith struggled to balance recognition of moral diversity with a universal moral framework and a commitment to a particular interpretation of progress through history. These arguments have a wider significance as they point towards some of the issues at stake in liberal anti-colonial arguments more generally

A Re-Investigation of a Chondritic Xenolith in the Murchsion (CM2) Chondrite: Formation by Fluid-Assisted Percolation During Metamorphism

The CM chondrites are generally complex impact breccias, in which lithic clasts and mineral fragments showing various degrees of aqueous alteration and possibly originating from different parent bodies are mixed together. The occurrence of CM-like clasts in other chondritic and achondritic meteorite breccias is also well-documented, however, reports on the occurrence of foreign clasts in CM chondrites are rare. In this study, we reinvestigated the white clast in the Murchison CM chondrite and demonstrate that the clast is not related to R chondrites as earlier suggested. In addition to the classification we discuss the origin and the history of its formation by studying several aspects like mineralogy, bulk chemistry, Rare Earth Elements (REE), oxygen isotopes, and the soluble organic compounds

The role of obesity, different fat compartments and sleep apnea severity in circulating leptin levels: the Icelandic Sleep Apnea Cohort study.

To access publisher's full text version of this article. Please click on the hyperlink in Additional Links field.To assess whether sleep apnea severity has an independent relationship with leptin levels in blood after adjusting for different measures of obesity and whether the relationship between obstructive sleep apnea (OSA) severity and leptin levels differs depending on obesity level.Cross-sectional study of 452 untreated OSA patients (377 males and 75 females), in the Icelandic Sleep Apnea Cohort (ISAC), age 54.3±10.6 (mean±s.d.), body mass index (BMI) 32.7±5.3 kg m(-2) and apnea-hypopnea index 40.2±16.1 events per h. A sleep study and magnetic resonance imaging of abdominal visceral and subcutaneous fat volume were performed, as well as fasting serum morning leptin levels were measured.Leptin levels were more highly correlated with BMI, total abdominal and subcutaneous fat volume than visceral fat volume per se. No relationship was found between sleep apnea severity and leptin levels, assessed within three BMI groups (BMI or =35 kg m(-2)). In a multiple linear regression model, adjusted for gender, BMI explained 38.7% of the variance in leptin levels, gender explained 21.2% but OSA severity did not have a significant role and no interaction was found between OSA severity and BMI on leptin levels. However, hypertension had a significant effect on the interaction between OSA severity and obesity (P=0.04). In post-hoc analysis for nonhypertensive OSA subjects (n=249), the association between leptin levels and OSA severity explained a minor but significant variance (3.2%) in leptin levels. This relationship was greatest for nonobese nonhypertensive subjects (significant interaction with obesity level). No relationship of OSA severity and leptin levels was found for hypertensive subjects (n=199).Obesity and gender are the dominant determinants of leptin levels. OSA severity is not related to leptin levels except to a minor degree in nonhypertensive nonobese OSA subjects.NIH/HL72067/HL94307, Eimskip Fund of the University of Iceland, Landspitali University Hospital Research Fun

Agreement in the scoring of respiratory events and sleep among international sleep centers.

To access publisher's full text version of this article. Please click on the hyperlink in Additional Links field.Abstract STUDY OBJECTIVES: The American Academy of Sleep Medicine (AASM) guidelines for polysomnography (PSG) scoring are increasingly being adopted worldwide, but the agreement among international centers in scoring respiratory events and sleep stages using these guidelines is unknown. We sought to determine the interrater agreement of PSG scoring among international sleep centers. DESIGN: Prospective study of interrater agreement of PSG scoring. SETTING: Nine center-members of the Sleep Apnea Genetics International Consortium (SAGIC). MEASUREMENTS AND RESULTS: Fifteen previously recorded deidentified PSGs, in European Data Format, were scored by an experienced technologist at each site after they were imported into the locally used analysis software. Each 30-sec epoch was manually scored for sleep stage, arousals, apneas, and hypopneas using the AASM recommended criteria. The computer-derived oxygen desaturation index (ODI) was also recorded. The primary outcome for analysis was the intraclass correlation coefficient (ICC) of the apnea-hypopnea index (AHI). The ICCs of the respiratory variables were: AHI = 0.95 (95% confidence interval: 0.91-0.98), total apneas = 0.77 (0.56-0.87), total hypopneas = 0.80 (0.66-0.91), and ODI = 0.97 (0.93-0.99). The kappa statistics for sleep stages were: wake = 0.78 (0.77-0.79), nonrapid eye movement = 0.77 (0.76-0.78), N1 = 0.31 (0.30-0.32), N2 = 0.60 (0.59-0.61), N3 = 0.67 (0.65-0.69), and rapid eye movement = 0.78 (0.77-0.79). The ICC of the arousal index was 0.68 (0.50-0.85). CONCLUSION: There is strong agreement in the scoring of respiratory events among the SAGIC centers. There is also substantial epoch-by-epoch agreement in scoring sleep variables. Our results suggest that centralized scoring of PSGs may not be necessary in future research collaboration among international sites where experienced, well-trained scorers are involved.NHLBI P01 HL094307 HL093463 Tzagournis Medical Research Endowment Funds of The Ohio State Universit

Boundary Conditions on Internal Three-Body Wave Functions

For a three-body system, a quantum wave function $\Psi^\ell_m$ with definite $\ell$ and $m$ quantum numbers may be expressed in terms of an internal wave function $\chi^\ell_k$ which is a function of three internal coordinates. This article provides necessary and sufficient constraints on $\chi^\ell_k$ to ensure that the external wave function $\Psi^\ell_m$ is analytic. These constraints effectively amount to boundary conditions on $\chi^\ell_k$ and its derivatives at the boundary of the internal space. Such conditions find similarities in the (planar) two-body problem where the wave function (to lowest order) has the form $r^{|m|}$ at the origin. We expect the boundary conditions to prove useful for constructing singularity free three-body basis sets for the case of nonvanishing angular momentum.Comment: 41 pages, submitted to Phys. Rev.