The Signature of Single-Degenerate Accretion Induced Collapse

The accretion induced collapse (AIC) of a white dwarf to a neutron star has long been suggested as a natural theoretical outcome in stellar evolution, but there has never been a direct detection of such an event. This is not surprising since the small amount of radioactive nickel synthesized ($\sim10^{-3}\,M_\odot$) implies a relatively dim optical transient. Here we argue that a particularly strong signature of an AIC would occur for an oxygen-neon-magnesium (ONeMg) white dwarf accreting from a star that is experiencing Roche-lobe overflow as it becomes a red giant. In such cases, the $\sim10^{50}\,{\rm erg}$ explosion from the AIC collides with and shock-heats the surface of the extended companion, creating an X-ray flash lasting $\sim1\,{\rm hr}$ followed by an optical signature that peaks at an absolute magnitude of $\sim -16$ to $-18$ and lasts for a few days to a week. These events would be especially striking in old stellar environments where hydrogen-rich supernova-like, transients would not normally be expected. Although the rate of such events is not currently known, we describe observing strategies that could be utilized with high cadence surveys that should either detect these events or place strong constraints on their rates.Comment: Revised version accepted for publication in The Astrophysical Journal, 5 pages, 2 figure

Level of youth voice in the decision-making process within the 4-H youth development program as perceived by State 4-H Program Leaders, State 4-H Youth Development Specialists, and 4-H Agents/Educators

This study aimed at determining the level of inclusiveness of youth voice in the decision-making process in the 4-H youth development program. It described the 4-H program’s position on youth voice among State 4-H Program Leaders, 4-H State Youth Development Specialists, and 4-H Youth Agents/Educators. The information gathered was utilized in identifying the level of inclusiveness of youth voice in the decision-making process to better understand how to suit youth’s needs, identify promising practices, and barriers. Three underlying constructs were identified that represented State 4-H Program Leader’s, 4-H Youth Development Specialist’s, and 4-H Agent’s/Educator’s personal views on youth voice in the decision-making process. They are as follows: Adult Initiated, Youth Involved; Youth Led, Adult Supported; and Youth Involved, Adult Decision-Making. Findings indicated that as an organization, 4-H, has to gather emerging research on youth voice and base trainings that address the primary issue of youth voice. Four-H needs to become more directional in its purpose and focus on trainings and issues that will aid youth development professionals in becoming true youth developers that address the needs of youth in our nation. Most interaction with youth within the 4-H program takes place at the county/parish level. It is evident that 4-H needs to include youth voice at the state level to ensure that youth needs are being met at the higher levels within the organization. While aware of emerging research on youth voice, 4-H state faculty, need to value the benefits of this new ideology. When viewing youth voice inclusion from the standpoint of organizational culture, it was found that as a youth development program, 4-H has a double standard on including youth voice in the decision-making process. The 4-H youth development program can not include them as full partners and let them have little choice on how and when they participate. Four-H creates a sense of mistrust with youth, and this type of inconsistency will negatively affect youth voice on all levels. It will take time for the organizational culture to shift the paradigm and recognize and adjust the value of, and respect youth voice in the decision-making process

An Introduction to Homological Algebra and its Applications

Ext modules have a number of applications in homological algebra and commutative abstract algebra as a whole. In this document we prove Ext modules are well-defined and motivate their study by characterizing the depth of a ring in terms of Ext modules as well as by giving an application in combinatorial commutative algebra. In particular, we give a way of constructing Cohen-Macaulay rings from simple graphs and show that when we localize these rings, their type is easily computed by counting the number of maximal cliques in the appropriate simple graph. When R is a noetherian ring and S the local ring resulting from localizing R at one of its prime ideals, it has been shown that there is a well-defined map from the set of isomorphism classes of semidualizing modules of R to the set of isomorphism classes of semidualizing modules of S. We use the same ring construction mentioned above to show this map need not be surjective

Minimal Differential Graded Algebra Resolutions Related to Certain Stanley-Reisner Rings

We investigate algebra structures on resolutions of a special class of Cohen-Macaulay simplicial complexes. Given a simplicial complex, we define a pure simplicial complex called the purification. These complexes arise as a generalization of certain independence complexes and the resultant Stanley-Reisner rings have numerous desirable properties, e.g., they are Cohen-Macaulay. By realizing the purification in the context of work of D\u27alì, et al., we obtain a multi-graded, minimal free resolution of the Alexander dual ideal of the Stanley-Reisner ideal. We augment this in a standard way to obtain a resolution of the quotient ring, which is likewise minimal and multi-graded. Ultimately, we propose an explicit product on the resolution and prove that, if associative, this product imparts a differential graded (DG) algebra structure on the minimal resolution

Forgiveness and mental health : a comparison across monotheistic religions

This study examined the relationship between forgiveness and mental health. Additionally, the study compared two monotheistic religions (i.e. Judaism, Christianity) with respect to the practice and conceptualization of forgiveness. Participants from the Jewish and Christian religions were recruited from several Midwestern churches and synagogues. Participants answered self-report questionnaires concerning religiousness, forgiveness, and mental health (e.g. anger, hope, depression, and spiritual well-being). Consistent with hypotheses, Forgiveness (AN) and Forgiveness (PP) were negatively correlated with state anger and positively correlated with existential well-being after controlling for the effects o f demographics and religiousness. Additionally, Forgiveness (AN) was negatively correlated with depression, and positively correlated with religious well-being. Contrary to hypotheses, the tendency to forgive across situations was not significantly correlated with any of the mental health measures. Contrary to hypotheses, no significant differences were found between Christian and Jewish participants with respect to the practice of forgiveness after controlling for the effects of demographics and religiousness. Consistent with hypotheses, Christian participants were more likely to agree with statements that embraced unconditional forgiveness, while Jewish participants were more likely to agree with statements supporting conditional forgiveness

Autonomous power system intelligent diagnosis and control

The Autonomous Power System (APS) project at NASA Lewis Research Center is designed to demonstrate the abilities of integrated intelligent diagnosis, control, and scheduling techniques to space power distribution hardware. Knowledge-based software provides a robust method of control for highly complex space-based power systems that conventional methods do not allow. The project consists of three elements: the Autonomous Power Expert System (APEX) for fault diagnosis and control, the Autonomous Intelligent Power Scheduler (AIPS) to determine system configuration, and power hardware (Brassboard) to simulate a space based power system. The operation of the Autonomous Power System as a whole is described and the responsibilities of the three elements - APEX, AIPS, and Brassboard - are characterized. A discussion of the methodologies used in each element is provided. Future plans are discussed for the growth of the Autonomous Power System

Evaluating Density Forecasts

We propose methods for evaluating density forecasts. We focus primarily on methods that are applicable regardless of the particular user's loss function. We illustrate the methods with a detailed simulation example, and then we present an application to density forecasting of daily stock market returns. We discuss extensions for improving suboptimal density forecasts, multi-step-ahead density forecast evaluation, multivariate density forecast evaluation, monitoring for structural change and its relationship to density forecasting, and density forecast evaluation with known loss function.

Evaluating density forecasts

The authors propose methods for evaluating and improving density forecasts. They focus primarily on methods that are applicable regardless of the particular user's loss function, though they take explicit account of the relationships between density forecasts, action choices, and the corresponding expected loss throughout. They illustrate the methods with a detailed series of examples, and they discuss extensions to improving and combining suboptimal density forecasts, multistep-ahead density forecast evaluation, multivariate density forecast evaluation, monitoring for structural change and its relationship to density forecasting, and density forecast evaluation with known loss function.Forecasting