Comment on "First order amorphous-amorphous transformation in silica"

In a recent letter (Phys. Rev. Lett. 84, 4629 (2000)), Lacks presents evidence of a first order amorphous-amorphous transition in silica at T=0. He calculates the free energy along a path of compression and successive decompression of a sample of 108 SiO2 units. The free energy of the two branches cross each other, and this is interpreted as evidence of a first order transition. We show that this conclusion does not follow from the shown data, since qualitatively the same phenomenology is obtained in a model where a first order transition does not exist.Comment: 1 page, 1 figure, to appear in Phys. Rev. Let

Modeling, Design And Evaluation Of Networking Systems And Protocols Through Simulation

Computer modeling and simulation is a practical way to design and test a system without actually having to build it. Simulation has many benefits which apply to many different domains: it reduces costs creating different prototypes for mechanical engineers, increases the safety of chemical engineers exposed to dangerous chemicals, speeds up the time to model physical reactions, and trains soldiers to prepare for battle. The motivation behind this work is to build a common software framework that can be used to create new networking simulators on top of an HLA-based federation for distributed simulation. The goals are to model and simulate networking architectures and protocols by developing a common underlying simulation infrastructure and to reduce the time a developer has to learn the semantics of message passing and time management to free more time for experimentation and data collection and reporting. This is accomplished by evolving the simulation engine through three different applications that model three different types of network protocols. Computer networking is a good candidate for simulation because of the Internet\u27s rapid growth that has spawned off the need for new protocols and algorithms and the desire for a common infrastructure to model these protocols and algorithms. One simulation, the 3DInterconnect simulator, simulates data transmitting through a hardware k-array n-cube network interconnect. Performance results show that k-array n-cube topologies can sustain higher traffic load than the currently used interconnects. The second simulator, Cluster Leader Logic Algorithm Simulator, simulates an ad-hoc wireless routing protocol that uses a data distribution methodology based on the GPS-QHRA routing protocol. CLL algorithm can realize a maximum of 45% power savings and maximum 25% reduced queuing delay compared to GPS-QHRA. The third simulator simulates a grid resource discovery protocol for helping Virtual Organizations to find resource on a grid network to compute or store data on. Results show that worst-case 99.43% of the discovery messages are able to find a resource provider to use for computation. The simulation engine was then built to perform basic HLA operations. Results show successful HLA functions including creating, joining, and resigning from a federation, time management, and event publication and subscription

The Relationship Between School Climate and Teacher Self-Efficacy in a Rural Virginia School System

School climate is one of the most significant factors in solidifying an effective learning environment. In today’s complex educational system, leaders face daily challenges in the world of high stakes testing and state accreditation that force them to ensure that they have implemented reforms that will provide sustained improvement in student achievement. As a result, school leaders and teachers must possess the ability to change and adapt to their conditions for continuous organizational improvement despite possible resistance from stakeholders. Moreover, with diverse teacher experience levels, leaders consistently assess and evaluate the instructional practices in their building to empower teachers to engage and motivate their students (Kelley, Thornton, & Daugherty, 2005). Thus, the school’s educational leader and the climate that he or she helps to establish directly impacts the school’s environment and teachers’ perception of that environment

The Relationships Between School Climate, Teacher Self-Efficacy, and Teacher Beliefs

This quantitative study examined the relationship between school climate, teacher self-efficacy, and teacher beliefs. Teachers at two middle schools in rural southern Virginia participated in the study. Middle school teachers were surveyed using the School Climate Index to collect information about teacher-perceived views on their school’s climate and the Teacher Sense of Efficacy Scale to gather information about teacher self-efficacy. Pearson Product-Moment Correlations were used to measure the relationship between school climate and teacher self-efficacy as well as teacher self-efficacy and four teacher-perceived climate factors, including collegial leadership, teacher professionalism, academic press, and community engagement. Data analysis did not provide evidence of a significant relationship between school climate and teacher self-efficacy. A positive correlation, however, was found in the relationship between teacher self-efficacy and community engagement. Recommendations for future research include replicating this study in elementary and high schools as well as in schools with different demographics, populations, and accreditation statuses to determine generalizations about school climate and teacher self-efficacy

An Exploration of Marital Health and Stress Among Military Couples

There are approximately 1.5 million active duty service members in today's military (Department of Defense [DoD], 2010) and approximately 726,000 (56.4%) of these individuals are married (DoD, 2010). Although the military offers benefits for married personnel, military couples also experience many hardships due to the demands from being in the armed forces (Laser & Stephens, 2011) and the stressors and challenges of military life may leave military members and their spouses more at risk for marital strain. The factors that garner the most attention for disruption and positive outcomes in relationships are the presence and process of deployment, changes in rank, and marital and physiological stress. The present study examined how factors , such as, deployment, rank, and length of time in the service, influence military personnel, their spouse, and their marital health (marital satisfaction, adjustment, and quality). This study took place within a family medicine practice on an Air Force base in the southeastern United States and data was collected from patients and their spouses using self-report measures and biomarkers (e.g., blood pressure and heart rate variability). Correlations were run to examine significant relationships between deployment, rank, length of time in the service, physiological stress and marital satisfaction, adjustment, and quality. Ultimately, the present study attempted to aid evidence based policy to support military couples since the deterioration of marital relationships has the ability to impact the performance of military personnel, which could ultimately have an impact on national security.  M.S

THE BIOPSYCHOSOCIAL-SPIRITUAL HEALTH OF ACTIVE DUTY WOMEN: SERVICE MEMBERS IN NEED OF SERVICE

Given the growing number of women who serve in the military, it is critical that mental health clinicians, medical providers, researchers, and policy makers are aware of the unique biological, psychological, social, and spiritual health concerns of active duty women. A holistic approach to health and health care recognizes that the mind, body, and spirit are all relevant in the context of health and illness and thus essential to determining readiness and fit for duty. While the health of women veterans has received some attention in the research, a chasm exists in the literature on the biopsychosocial-spiritual (BPSS) health of active duty women. This dissertation includes six chapters, comprising an introduction to the dissertation, a literature review on active duty women's biopsychosocial-spiritual health, two publishable manuscripts: (a) a systematic review of research published on the BPSS health of active duty women, and (b) an empirical research study on the BPSS health experiences of active duty women, and a discussion chapter that offers future clinical, research, and policy implication to better serve this population

Predictors of improvement in subjective sleep quality reported by older adults following group-based cognitive behavior therapy for sleep maintenance and early morning awakening insomnia

ObjectiveCognitive behavior therapy is an effective nonpharmacologic treatment for insomnia. However, individualized administration is costly and often results in substantial variability in treatment response across individual patients, particularly so for older adults. Group-based administration has demonstrated impressive potential for a brief and inexpensive answer to the effective treatment of insomnia in the older population. It is important to identify potential predictors of response to such a treatment format to guide clinicians when selecting the most suitable treatment for their patients. The aim of our study was to identify factors that predict subjective sleep quality of older adults following group-based administration of cognitive behavior therapy for insomnia (CBT-I).MethodsEighty-six adults (41 men; mean age, 64.10 y; standard deviation [SD], 6.80) with sleep maintenance or early morning awakening insomnia were selected from a community-based sample to participate in a 4-week group-based treatment program of CBT-I. Participants were required to complete 7-day sleep diaries and a comprehensive battery of questionnaires related to sleep quality and daytime functioning. Hierarchical multiple regression analyses were used to identify factors predicting subjective sleep quality immediately following treatment and at 3-month follow-up. Sleep diaries reported average nightly sleep efficiency (SE), which was used as the outcome measure of sleep quality.Results and conclusionsParticipants with the greatest SE following treatment while controlling for pretreatment SE were relatively younger and had more confidence in their ability to sleep at pretreatment. These characteristics may be useful to guide clinicians when considering the use of a group-based CBT-I for sleep maintenance or early morning awakening insomnia in older adults.Nicole Lovato, Leon Lack, Helen Wright, David J. Kennawa

The DNases of pathogenic Lancefield streptococci

DNases are abundant among the pathogenic streptococci, with most species harbouring genes for at least one. Despite their prevalence, however, the role for these extracellular enzymes is still relatively unclear. The DNases of the Lancefield group A Streptococcus, S. pyogenes are the best characterized, with a total of eight DNase genes identified so far. Six are known to be associated with integrated prophages. Two are chromosomally encoded, and one of these is cell-wall anchored. Homologues of both prophage-associated and chromosomally encoded S. pyogenes DNases have been identified in other streptococcal species, as well as other unique DNases. A major role identified for streptococcal DNases appears to be in the destruction of extracellular traps produced by immune cells, such as neutrophils, to ensnare bacteria and kill them. These traps are composed primarily of DNA which can be degraded by the secreted and cell-wall-anchored streptococcal DNases. DNases can also reduce TLR-9 signalling to dampen the immune response and produce cytotoxic deoxyadenosine to limit phagocytosis. Upper respiratory tract infection models of S. pyogenes have identified a role for DNases in potentiating infection and transmission, possibly by limiting the immune response or through some other unknown mechanism. Streptococcal DNases may also be involved in interacting with other microbial communities through communication, bacterial killing and disruption of competitive biofilms, or control of their own biofilm production. The contribution of DNases to pathogenesis may therefore be wide ranging and extend beyond direct interference with the host immune response