Space Station Freedom altitude strategy

The Space Station Freedom (SSF) altitude strategy provides guidelines and assumptions to determine an altitude profile for Freedom. The process for determining an altitude profile incorporates several factors such as where the Space Shuttle will rendezvous with the SSF, when reboosts must occur, and what atmospheric conditions exist causing decay. The altitude strategy has an influence on all areas of SSF development and mission planning. The altitude strategy directly affects the micro-gravity environment for experiments, propulsion and control system sizing, and Space Shuttle delivery manifests. Indirectly the altitude strategy influences almost every system and operation within the Space Station Program. Evolution of the SSF altitude strategy has been a very dynamic process over the past few years. Each altitude strategy in turn has emphasized a different consideration. Examples include a constant Space Shuttle rendezvous altitude for mission planning simplicity, or constant micro-gravity levels with its inherent emphasis on payloads, or lifetime altitudes to provide a safety buffer to loss of control conditions. Currently a new altitude strategy is in development. This altitude strategy will emphasize Space Shuttle delivery optimization. Since propellant is counted against Space Shuttle payload-to-orbit capacity, lowering the rendezvous altitude will not always increase the net payload-to-orbit, since more propellant would be required for reboost. This altitude strategy will also consider altitude biases to account for Space Shuttle launch slips and an unexpected worsening of atmospheric conditions. Safety concerns will define a lower operational altitude limit, while radiation levels will define upper altitude constraints. The evolution of past and current SSF altitude strategies and the development of a new altitude strategy which focuses on operational issues as opposed to design are discussed

Noncompete Contracts: Understanding the Cost of Unpredictability

The intention of this Article, and the brief presentation that accompanied it at the Texas Wesleyan University School of Law Symposium on The Role of Contract in the Modern Employment Relationship, is to highlight the need for a more uniform and consistent application of contract principles to noncompete contracts in order to increase predictability in this field of law. Presently both employees and employers pay a heavy price due to increased uncertainty in this area. This is because courts use equitable concepts to circumvent basic contract law principles without recognizing the unseen price that is paid by others when contract-based predictability is eroded. To illustrate this point, this Article will begin with six different scenarios that are very real possibilities under the current state of the law and highlight the practical cost to litigants in the current unpredictable environment. In addition to highlighting a significant problem created by the unpredictability in this area of employment contract law, this Article will also provide the practicing employment law attorney with a review of different contract options to consider when drafting noncompete contracts and similar protective agreements. In Part II, the nature of unpredictability in a number of key foundational concepts like protectable interests, consideration, and choice of law is examined. In Part III, an overview of advantages and disadvantages to the eight most common forms of restrictive contracts are covered to illustrate that no one contract option solves the present unpredictability problem and to provide the practicing attorney with a helpful checklist of contract options to consider. To conclude, a suggestion for a more balanced approach to improve predictability is provided

Learning Theory Expertise in the Design of Learning Spaces: Who Needs a Seat at the Table?

This study highlights the impact of including stakeholders with expertise in learning theory in a learning space design process. We present the decision-making process during the design of the Krause Innovation Studio on the campus of the Pennsylvania State University to draw a distinction between the architect and faculty member’s decision-making process. Often, the architect relied on guiding principles such as flexibility, while the faculty member drew from learning theory such as the sociocultural theory of learning (Vygotsky, 1978). This study demonstrates the value of learning theory expertise and includes suggestions and possible implications for future designs of learning spaces

Phase Zero

In October 2006 General Charles Wald, Deputy Commander U.S. European Com- mand, brought “Phase Zero” into the joint lexicon with the publication of an article, “The Phase Zero Campaign.”1 Over the last five years the concept of taking coordinated action in peacetime to affect the strategic environment has becomewidely accepted and is now integrated into theater campaign plans. These activi- ties focus on building capacity of partners and influencing potential adversaries to avoid war. In contrast, Chinese strategic culture has encouraged taking actions to defeat an enemy prior to the onset of hostilities for two and a half millennia

New proof-of-concept in viral inactivation: virucidal efficacy of 405 nm light against feline calicivirus as a model for norovirus decontamination

The requirement for novel decontamination technologies for use in hospitals is ever present. One such system uses 405 nm visible light to inactivate microorganisms via ROS-generated oxidative damage. Although effective for bacterial and fungal inactivation, little is known about the virucidal effects of 405 nm light. Norovirus (NoV) gastroenteritis outbreaks often occur in the clinical setting, and this study was designed to investigate potential inactivation effects of 405 nm light on the NoV surrogate, feline calicivirus (FCV). FCV was exposed to 405 nm light whilst suspended in minimal and organically-rich media to establish the virucidal efficacy and the effect biologically-relevant material may play in viral susceptibility. Antiviral activity was successfully demonstrated with a 4 Log10 (99.99%) reduction in infectivity when suspended in minimal media evident after a dose of 2.8 kJ cm−2. FCV exposed in artificial faeces, artificial saliva, blood plasma and other organically rich media exhibited an equivalent level of inactivation using between 50–85% less dose of the light, indicating enhanced inactivation when the virus is present in organically-rich biologically-relevant media. Further research in this area could aid in the development of 405 nm light technology for effective NoV decontamination within the hospital environment

Exploring Resilience Models in a Sample of Combat-Exposed Military Service Members and Veterans: A Comparison and Commentary

Background: The term resilience is applied in numerous ways in the mental health field, leading to different perspectives of what constitutes a resilient response and disparate findings regarding its prevalence following trauma. Objective: illustrate the impact of various definitions on our understanding and prevalence of resilience, we compared various resilience definitions (absence of PTSD, absence of current mental health diagnosis, absence of generalized psychological distress, and an alternative trauma load–resilience discrepancy model of the difference between actual and predicted distress given lifetime trauma exposure) within a combat-exposed military personnel and veteran sample. Method: In this combat-trauma exposed sample (N = 849), of which approximately half were treatment seeking, rates of resilience were determined across all models, the kappa statistic was used to determine the concordance and strength of association across models, and t-tests examined the models in relation to a self-reported resilience measure. Results: Prevalence rates were 43.7%, 30.7%, 87.4%, and 50.1% in each of the four models. Concordance analyses identified 25.7% (n = 218) considered resilient by all four models (kappa = .40, p \u3c .001). Correlations between models and self-reported resilience were strong, but did not fully overlap. Conclusions:The discussion highlights theoretical considerations regarding the impact of various definitions and methodologies on resilience classifications, links current findings to a systems-based perspective, and ends with suggestions for future research approaches on resilience

Symptom improvement and remission in untreated adults seeking treatment for obsessive-compulsive disorder: A systematic review and meta-analysis.

Obsessive-compulsive disorder (OCD) is a common psychiatric condition that results in significant distress and impairment, and high societal costs. OCD is widely considered to be a chronic condition, however, our understanding of the chronicity of the disorder, and the incidence of spontaneous remission, has largely relied on longitudinal studies of individuals who have received treatment. The aim of the current study is to examine symptom improvement and rate of spontaneous remission in individuals with OCD who were assigned to a no-treatment control group within a randomized controlled trial using a meta-analytic approach. Twelve studies (n = 282; mean age = 35.52; 60.03 % female) were included in the meta-analysis. The pooled within-group effect size was negligible (g = -0.14; 95 % CI [-0.25, -0.04]) and only 4 % of participants demonstrated spontaneous remission across an average of 10.92 weeks (event rate = 0.04; [95 % CI: 0.01, 0.11]). Sample size and duration of OCD symptoms significantly moderated the effect size for symptom change. No moderators were found for symptom remission. The findings add to the small body of literature demonstrating that OCD has a chronic and unremitting course without treatment

Forming and Sustaining a Learning Community and Developing Implicit Collective Goals in an Open Future Learning Space

This study investigates the role of space, material, and affect in undergraduate and graduate students’ lived experiences within an open Future Learning Space (FLS) and speaks to the call for research on learning communities in learning spaces, as described in Hod, Bielaczyc, and Ben-Zvi (2018). The methodological approach consists of semi-structured phenomenological interviews with thirteen users of the FLS and thematic analysis to uncover themes. Findings suggest the FLS was able to: (1) bring together individuals by producing individual and shared affective responses; (2) hold community together and inform perceptions; and (3) move the community together and shape practices. This study indicates that open FLSs are complex systems constructed by users and can meet some of the criteria for a learning community (LC), especially if we broaden the definitions to take into account implicit versions of an LC

A Lanthanide-Based Chemosensor for Bioavailable Fe3+ Using a Fluorescent Siderophore: An Assay Displacement Approach

The measurement of trace analytes in aqueous systems has become increasingly important for understanding ocean primary productivity. In oceanography, iron (Fe) is a key element in regulating ocean productivity, microplankton assemblages and has been identified as a causative element in the development of some harmful algal blooms. The chemosenor developed in this study is based on an indicator displacement approach that utilizes time-resolved fluorescence and fluorescence resonance energy transfer as the sensing mechanism to achieve detection of Fe3+ ions as low as 5 nM. This novel approach holds promise for the development of photoactive chemosensors for ocean deployment

Weighted complex projective 2-designs from bases: optimal state determination by orthogonal measurements

We introduce the problem of constructing weighted complex projective 2-designs from the union of a family of orthonormal bases. If the weight remains constant across elements of the same basis, then such designs can be interpreted as generalizations of complete sets of mutually unbiased bases, being equivalent whenever the design is composed of d+1 bases in dimension d. We show that, for the purpose of quantum state determination, these designs specify an optimal collection of orthogonal measurements. Using highly nonlinear functions on abelian groups, we construct explicit examples from d+2 orthonormal bases whenever d+1 is a prime power, covering dimensions d=6, 10, and 12, for example, where no complete sets of mutually unbiased bases have thus far been found.Comment: 28 pages, to appear in J. Math. Phy