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Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS: I. Asteroseismology of the GW Vir stars RX J2117+3412, HS 2324+3944, NGC 6905, NGC 1501, NGC 2371, and K 1-16
No full textThe recent arrival of continuous photometric observations of unprecedented quality from space missions has strongly promoted the study of pulsating stars and caused great interest in the stellar astrophysics community. In the particular case of pulsating white dwarfs, the TESS mission is taking asteroseismology of these compact stars to a higher level, emulating or even surpassing the performance of its predecessor, the Kepler mission. Aims. We present a detailed asteroseismological analysis of six GW Vir stars that includes the observations collected by the TESS mission. Methods. We processed and analyzed TESS observations of RX J2117+3412 (TIC 117070953), HS 2324+3944 (TIC 352444061), NGC 6905 (TIC 402913811), NGC 1501 (TIC 084306468), NGC 2371 (TIC 446005482), and K 1-16 (TIC 233689607). We carried out a detailed asteroseismological analysis of these stars on the basis of PG 1159 evolutionary models that take into account the complete evolution of the progenitor stars. We constrained the stellar mass of these stars by comparing the observed period spacing with the average of the computed period spacings, and we employed the individual observed periods to search for a representative seismological model when possible. Results. In total, we extracted 58 periodicities from the TESS light curves of these GW Vir stars using a standard prewhitening procedure to derive the potential pulsation frequencies. All the oscillation frequencies that we found are associated with g-mode pulsations, with periods spanning from ∼817 s to ∼2682 s. We find constant period spacings for all but one star (K 1-16), which allowed us to infer their stellar masses and constrain the harmonic degree ℓ of the modes. Based on rotational frequency splittings, we derive the rotation period of RX J2117+3412, obtaining a value in agreement with previous determinations. We performed period-to-period fit analyses on five of the six analyzed stars. For four stars (RX J2117+3412, HS 2324+3944, NGC 1501, and NGC 2371), we were able to find an asteroseismological model with masses that agree with the stellar mass values inferred from the period spacings and are generally compatible with the spectroscopic masses. Obtaining seismological models allowed us to estimate the seismological distance and compare it with the precise astrometric distance measured with Gaia. Finally, we find that the period spectrum of K 1-16 exhibits dramatic changes in frequency and amplitude that together with the scarcity of modes prevented us from meaningful seismological modeling of this star. Conclusions. The high-quality data collected by the TESS space mission, considered simultaneously with ground-based observations, provide very valuable input to the asteroseismology of GW Vir stars, similar to the case of other classes of pulsating white dwarf stars. The TESS mission, in conjunction with future space missions and upcoming surveys, will make impressive progress in white dwarf asteroseismology
Exploratory Factor Analysis of the VB-MAPP: Support for the Interdependency of Elementary Verbal Operants
No full textCompeting viewpoints on the independency or interdependency of Skinner’s verbal operants have been discussed in the literature and with empirical support for both positions generated using single-case research methods. Our study provides support for the interdependency of the verbal operants using items contained in the Verbal Behavior Milestones Assessment and Placement Program as a measure of broader skill acquisition in each verbal operant category and across skill complexity levels. The result of an exploratory factor analysis conducted across 85 participants with autism suggested that items did yield factors consistent with the verbal operants, rather items appeared to cluster in terms of skill complexity producing a best-fit 2 factor model. Together with prior research showing untrained cross-operant transfers, results fail to support Skinner’s verbal behavior taxonomy distinguishing between the verbal operant categories as independent constructs, with implications for how behavior scientists and analysts describe language development and assess and treat language deficits of individuals with autism
The Effect of the Interaction of Exercise Training and Isolation on the Serotonergic System of App/Ps1 Mice
No full textAlzheimer’s disease (AD) is a complex neurodegenerative disease that is characterized by the deposition of amyloid beta (Ab) peptides and, consecutively, by a loss of memory and cognitive functions. The amyloid cascade hypothesis suggests that Ab deposition is the main pathogenic of AD. There is evidence that both changes in production and clearance of Ab may be involved in AD pathology. Past studies have shown that exercise training leads to an upregulation in proteins directly involved with Ab clearance. Chronic stress is thought to exacerbate AD pathology by increasing production of Ab. Studies have also demonstrated a link between serotonin signaling and decreased Ab production. Although these factors affecting AD pathology have each been investigated, the interplay between all three has yet to be evaluated. This study aimed to examine the effects of chronic stress and exercise training on both Ab levels, as well as serotonin signaling. APP/PS1 mice were divided into housing and exercise groups: sedentary and isolated, sedentary and socially housed, exercise trained and isolated, and exercise trained and socially housed. Mice were also divided based on sex. Due to the COVID-19 pandemic not all goals of this project were met. The results demonstrate that exercise training may be able to rescue the negative effects of isolation on Ab deposition; however, a training effect was not produced in the exercise trained groups, so the trends of this research may need to be reevaluated
Exploring the Influence of Self-Efficacy and Autonomy on Outdoor Recreation Behaviors during the Covid-19 Pandemic
No full textOutdoor Recreation (OR) provides the benefits of physical activity and traditional leisure along with the addition of the benefits associated with an outdoor environment. Self Determination Theory (SDT) and Social Cognitive Theory (SCT) state that self-efficacy (SE) and autonomy can increase depending on the physical and social environment. The purpose of this study was to explore the relationship between self-efficacy and autonomy on OR behaviors during the COVID-19 pandemic. It was hypothesized there would be a correlation between individuals who participate in OR activities and self-efficacy as well as autonomy. The research also explored barriers and facilitators to OR via qualitative data. Participant data was collected via a voluntary survey distributed nationwide using Qualtrics. Survey measures included demographics, OR behavior identification, COVID-19 Activity Survey, the Recreation Experience Preference Scale (REPv2), and the Outdoor Recreation Self-Efficacy Scale (ORSE). A statistically significant positive correlation existed between autonomy and self-efficacy (r = 0.138, p \u3c 0.01), as well as between self-efficacy and pre/post pandemic OR behaviors 2020 (r = 0.158,
Examining the county-level political considerations associated with declining reliance on the death penalty from 1990 to 2010*
No full textTheorists have placed considerable emphasis on the role that political factors play in shaping jurisdictional use of the death penalty. However, scholars have yet to empirically examine whether these political explanations account for reliance on this punishment across counties in the United States. Furthermore, empirical research that has examined the political factors associated with the dramatic decline in the use of the death penalty in the late 20th and early 21st centuries has been limited. In order to address these gaps in the literature, this study examines whether the variables derived from three political perspectives are associated with use of death sentences across 2,572 counties in the United States from 1990 to 2010. The results from this study indicate support for the key propositions within the partisan politics, religious fundamentalist sentiment, and economic threat hypotheses. However, in contrast to the results from prior studies, no support was shown for the direct relationship between the size of African American populations and local reliance on the death penalty
Gear specific catch rates and size structure of channel catfish in the Upper Mississippi River
No full textChannel catfish are important to the Mississippi River (i.e., ecologically, commercially, and recreationally). The dynamic rate functions (recruitment, growth, and mortality) of the population are important to proper management. However, different gears can produce varying estimates of these vital rates (e.g., size selectivity or age selectivity). We evaluated the effectiveness of three commonly used gear types for sampling channel catfish. Sampling was completed following United States Army Corps of Engineers\u27 Long-Term Resource Monitoring (LTRM) element sampling protocol; pulsed direct current daytime electrofishing, baited 37 mm hoop nets (large hoop net), baited 18 mm hoop nets (small hoop net), and a tandem hoop net set that included one large and one small hoop net. A total of 65,222 channel catfish were collected from 1993 to 2017. Channel catfish catch rates were lowest using daytime electrofishing and large hoop nets, while tandem hoop nets and small hoop nets had higher catch per unit effort (CPUE). Furthermore, tandem hoop nets collected a broader size distribution of channel catfish in comparison to daytime electrofishing, large hoop nets, and small hoop nets. As such, we recommend that tandem hoop nets should be used to evaluate channel catfish populations in the Upper Mississippi River as well as other riverine systems
Motives for corporate philanthropy and charitable causes supported
No full textPurpose: This paper examines how the inferred motives for corporate philanthropy relate to the types of charitable causes supported. Design/methodology/approach: Published data were obtained for 256 publicly traded and private corporations from a variety of sources. Findings: The results demonstrated that a number of motives were not significantly related to total charitable giving, but were related to how charitable funds were distributed to various charitable causes. Thus, the study provides insights on the strategic use of corporate charity as means of achieving various business objectives and advancing a theoretical understanding of corporate philanthropy strategies. Research limitations/implications: This study only investigated some of the presumed motives for corporate philanthropy. Even for the motives investigated in this study, no attempt was made to examine all the motivational factors that determine the level of need for a specific motive. Thus, while the present study provides some of the first evidence of a relationship between motivational factors and data on the types of charitable causes supported, there are other motivational factors that could be investigated in future studies. Practical implications: The results have a number of implications for managers of nonprofit organizations such as marketing/targeting potential donors. Additionally, the results could be useful for managers of for profit firms in terms of comparing corporate strategies with competing firms. Originality/value: The study provides a framework for investigating the relationship between motivational factors and types of charitable causes supported
Five letters to Georgia O\u27Keeffe: Or, meditations on dying in southwestern landscapes
No full textIn her lifetime, US American painter Georgia O\u27Keeffe (1887-1986) wrote thousands of letters to those closest to her. However, she relied on painting as her primary public voice. This essay takes the form of five letters, composed through posthumanist performative writing, addressed to O\u27Keeffe. I work through the process of experiencing the death of my father in a material landscape as it was painted by O\u27Keeffe. The southwestern landscapes O\u27Keeffe painted were the same landscapes in which my father and I negotiated material relations to live a life of what Donna Haraway calls “significant otherness.
Preparation, Properties and Crystal Structure of syn-Isomer of 2,6-Dichlorophenyl-cyanoxime, H(2,6-diCl-PhCO): Potent Carbonyl Reductase Inhibitor
No full textAbstract: The oximino(2,6-dichlorophenyl)acetonitrile, H(2,6-diCl-PhCO) has been synthesized in a reasonably high yield of 60%, and characterized using a variety of physical, electrochemical, spectroscopic methods and X-ray analysis. This compound belongs to the family of cyanoximes; a new subclass of oximes with the general formula NC–C(=N–OH)–R (where R is an electron-withdrawing group) which recently emerged as new biologically active compounds. This cyanoxime represents a disubstituted arylcyanoxime that was found to be a powerful inhibitor of the Carbonyl Reductase enzyme involved in the developing of resistance to anticancer treatment, and the making of cardiotoxic derivatives of anthracyclines that are currently used in medicine. The oximino(2,6-dichlorophenyl)acetonitrile, H(2,6-diCl-PhCO) is a weak acid with pKa = 6.17 and does not dissociate in organic polar protic and aprotic solvents. The cyanoxime was obtained as a microcrystalline mixture of two diastereomers (anti- and syn-) and deprotonates in solutions with the formation of yellow anions which exhibit solvatochromic behavior. However, one specific diastereomer—syn—was isolated in crystalline form from a solvent system as colorless blocks overlayed with pentane ether solution in a monoclinic system in a P2/c (#13) space group with unit cell parameters: a = 8.1720(2), b = 8.8013(3), c = 13.0146(4) and β = 102.546(3); Z = 4. A single crystal was studied using filtered CuKa radiation, providing Rint value of 0.0348 from a full-sphere of reflections. A crystal structure was solved using direct methods, and well refined to R1 = 0.0459, wR2 = 0.1268 and GOF = 1.107. The studied specimen of oximino(2,6-dichlorophenyl)acetonitrile, H(2,6-diCl-PhCO), represents a highly non-planar, rare syn-diastereomer in which the oxime fragment is positioned towards the chlorinated phenyl group. In the crystal, the compound forms a columnar structure extended along the c-direction by using slipped π–π stacking interactions. Columns are interconnected via H-bonding between the oxime OH-group and N atom of the nitrile group with the following parameters: N–H = 1.841 Å, and 169.20° N···H–O angle. No thermal interconversion of syn- into anti- diastereomer was observed upon heating of crystals of one isomer under flow of Ar
An Exploration of the Role of Farm Business Decisions in Addressing Financial Challenges for Missouri\u27s Beginning Farmers
No full textThe next generation of farmers takes an important role in the food production for subsequent years. The American Farm Bureau Federation’s (2017) estimation that 70% increase of production will need to be achieved within the next 30 years set awareness across the globe. Researchers have been studying and trying to find means to aid beginning farmers in a variety of ways. This study measures farm decisions that affect financial performance of farmers aiming to facilitate beginning producers’ decision making. Three regressions were used to analyze how different variables affect farmers’ profitability and repayment capacity. Using a county-level data for the state of Missouri significant results were found. Counties with less diversified farms show a lower financial performance. On the other hand, counties with more operations taking advantage of crop insurance present a better repayment capacity. Altogether, the findings in this study provide significant thoughts for future research and potential ways to help beginning farmers and ranchers to succeed