441 research outputs found

    On the chemical composition of Titan's dry lakebed evaporites

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    Titan, the main satellite of Saturn, has an active cycle of methane in its troposphere. Among other evidence for a mechanism of evaporation at work on the ground, dry lakebeds have been discovered. Recent Cassini infrared observations of these empty lakes have revealed a surface composition poor in water ice compared to that of the surrounding terrains --- suggesting the existence of organic evaporites deposits. The chemical composition of these possible evaporites is unknown. In this paper, we study evaporite composition using a model that treats both organic solids dissolution and solvent evaporation. Our results suggest the possibility of large abundances of butane and acetylene in the lake evaporites. However, due to uncertainties of the employed theory, these determinations have to be confirmed by laboratory experiments.Comment: Icarus, in pres

    Rigid Origami Vertices: Conditions and Forcing Sets

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    We develop an intrinsic necessary and sufficient condition for single-vertex origami crease patterns to be able to fold rigidly. We classify such patterns in the case where the creases are pre-assigned to be mountains and valleys as well as in the unassigned case. We also illustrate the utility of this result by applying it to the new concept of minimal forcing sets for rigid origami models, which are the smallest collection of creases that, when folded, will force all the other creases to fold in a prescribed way

    Black Students’ Perceived Socioemotional Safety On College Campuses

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    Research indicates that Black students experience college differently than their white counterparts; often, their minority racial status exposes them to discrimination and unfair treatment (Eschemann, 2020; Griffith et al., 2019; Pyke, 2018; Stotzer et al., 2012). These racialized incidents contribute to perceived socioemotional safety among Black students, including fear and experiences of bullying, exclusion, intolerance, hate speech, mental health, academic performance, and opportunities (Eschemann, 2020; Garces et al., 2022; Griffith et al., 2019; Pyke, 2018; Stotzer et al., 2012; Woldolff et al. 2011). The goal of this research is to explore the correlations between racial marginalization and discrimination and the perceived socioemotional safety of Black college students attending predominantly white institutions. Through Dr. Pryor’s Social Research Methods class, we examined students of color’s perceived socioemotional safety on college campuses by surveying an Introduction to Sociology class and other peers, analyzing secondary data, conducting content analysis, and interviewing students of color attending Belmont University. Our methodologies, processes, analyses, findings, and potential future research will be discussed in the upcoming presentation

    RISIKO PAJAK SEBAGAI PEMODERATOR PENGARUH CORPORATE SOCIAL RESPONSIBILITY TERHADAP PENGHINDARAN PAJA

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    The purpose of this paper is to investigate the effect of corporate social responsibility and penghindaran pajak with tax risk as the moderating variable. This study was performed on manufacturing sector in Indonesia. The samples used were 132 companies listed on the Indonesia Stock Exchange in the period 2014-2018. This study uses Moderated Regression Analysis (MRA) and is processed using SPSS version 22. We find evidence that businesses that better disclose their CSR, measured by awarding, are less likely to engage in penghindaran pajak activities. However, the existence of tax risks that a business has needs to be a concern. This study also found that tax risk can moderate by weakening the influence between CSR and penghindaran pajak

    Predictors of Arterial Stiffness in Law Enforcement Officers

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    Background: Compare arterial stiffness among law enforcement officers (LEOs) versus general population normative values and identify predictors of arterial stiffness in LEOs. Methods: Seventy male LEOs (age: 24–54 years) completed body composition, blood pressures, physical activity level, and carotid-femoral pulse wave velocity (cfPWV) measurements. T-tests and regression analyses were utilized to compare LEO data to normative data and predict cfPWV, respectively. Results: Compared to similar age strata within the general population, cfPWV was lower among LEO’s under 30-years (mean difference = −0.6 m·s−1), but higher among LEOs 50–55-years (mean difference = 1.1 m·s−1). Utilizing regression, age, relative body fat, and diastolic blood pressure explained the greatest variance in LEO’s cfPWV (adj. R2 = 0.56, p \u3c 0.001). Conclusion: This investigation demonstrated that arterial stiffness may progress more rapidly in LEOs and LEOs’ relative body fat and blood pressure may primarily affect arterial stiffness and risk of CVD

    A Pilot Search for Population III Supernova Candidates in the Spitzer/IRAC Dark Field

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    We have undertaken a systematic search for candidate supernovae from high-redshift Population III stars in a field that has been observed with repeated imaging on a cadence of 2-3 weeks over a 2.2 year baseline, the Spitzer/IRAC Dark Field. The individual epochs reach a typical 5-sigma depth of 1 uJy in IRAC Channel 1 (3.6 um). Requiring a minimum of four epochs coverage, the total effective area searched is 214 sq arcminutes. The unprecedented depth and multi-epochal nature of these data make it ideal for a first foray to detect transient objects which may be candidate luminous Pair Instability Supernovae from the primordial-metallicity first stars. The search was conducted over a broad range of timescales, allowing for different durations of the putative candidates' light curve plateau phases. All candidates were vetted by inspection of the Spitzer imaging data, as well as deep HST/ACS F814W imaging available over the full field. While many resolved-source objects were found with Spitzer variability, no transient objects could plausibly be identified as high-redshift supernovae candidates. The resulting 95% confidence level upper limit is 23/sq deg/yr, for sources with plateau timescales under 400/(1+z) days and brightnesses above ~1 uJy.Comment: ApJL, in pres

    Public awareness, concerns, and priorities about anthropogenic impacts on marine environments

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    Numerous international bodies have advocated the development of strategies to achieve the sustainability of marine environments. Typically, such strategies are based on information from expert groups about causes of degradation and policy options to address them, but these strategies rarely take into account assessed information about public awareness, concerns, and priorities. Here we report the results of a pan-European survey of public perceptions about marine environmental impacts as a way to inform the formation of science and policy priorities. On the basis of 10,106 responses to an online survey from people in 10 European nations, spanning a diversity of socioeconomic and geographical areas, we examine the public’s informedness and concern regarding marine impacts, trust in different information sources, and priorities for policy and funding. Results show that the level of concern regarding marine impacts is closely associated with the level of informedness and that pollution and overfishing are two areas prioritized by the public for policy development. The level of trust varies greatly among different information sources and is highest for academics and scholarly publications but lower for government or industry scientists. Results suggest that the public perceives the immediacy of marine anthropogenic impacts and is highly concerned about ocean pollution, overfishing, and ocean acidification. Eliciting public awareness, concerns, and priorities can enable scientists and funders to understand how the public relates to marine environments, frame impacts, and align managerial and policy priorities with public demand

    Comparing oncologic outcomes in patients undergoing surgery for oncocytic neoplasms, conventional oncocytoma, and chromophobe renal cell carcinoma

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    Introduction Oncocytic neoplasms are renal tumors similar to oncocytoma, but their morphologic variations preclude definitive diagnosis. This somewhat confusing diagnosis can create treatment and surveillance challenges for the treating urologist. We hypothesize that these subtle morphologic variations do not drastically affect the malignant potential of these tumors, and we sought to demonstrate this by comparing clinical outcomes of oncocytic neoplasms to those of classic oncocytoma and chromophobe. Methods We gathered demographic and outcomes data for patients with variant oncocytic tumors. Oncologic surveillance was conducted per institutional protocol in accordance with NCCN guidelines. Descriptive statistics were used to compare incidence of metastasis and death against those for patients with oncocytoma and chromophobe. Three hundred and fifty-one patients were analyzed: 164 patients with oncocytoma, 28 with oncocytic neoplasms, and 159 with chromophobe tumors. Results Median follow-up time for the entire cohort was 32.4 months, (interquartile range 9.2–70.0). Seventeen total patients (17/351, 4.9%) died during the course of the study. In patients with oncocytoma or oncocytic neoplasm, none were known to metastasize or die of their disease. Only chromophobe tumors >6 cm in size in our series demonstrated metastatic progression and approximately half of these metastasized tumors demonstrated sarcomatoid changes. Conclusion Variant oncocytic neoplasms appear to have a natural course similar to classic oncocytoma. These tumors appear to have no metastatic potential, and oncologic surveillance may not be indicated after surgery
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