Experiences using lightweight formal methods for requirementsmodeling

The paper describes three case studies in the lightweight application of formal methods to requirements modeling for spacecraft fault protection systems. The case studies differ from previously reported applications of formal methods in that formal methods were applied very early in the requirements engineering process to validate the evolving requirements. The results were fed back into the projects to improve the informal specifications. For each case study, we describe what methods were applied, how they were applied, how much effort was involved, and what the findings were. In all three cases, formal methods enhanced the existing verification and validation processes by testing key properties of the evolving requirements and helping to identify weaknesses. We conclude that the benefits gained from early modeling of unstable requirements more than outweigh the effort needed to maintain multiple representations     

Andreev Bound-State Tunneling and ESR Spectroscopy of High-Temperature Superconductors and Observations of Broken Time-Reversal Symmetry

An emphasis on reliable materials growth and development of new fabrication techniques has allowed us to investigate the electronic structure of high-temperature superconductors by planar quasiparticle tunneling and electron paramagnetic resonance (EPR) spectroscopies. The quasiparticle (QP) density of states (DoS) is investigated by tunneling into oriented thin films of Y₁Ba₂Cu₃O₇ (YBCO) and single crystals of Ba₂Sr₂Ca₁Cu₂O₈ (BSCCO). Data are obtained as a function of crystallographic orientation, temperature, doping, damage, and applied magnetic field. These data demonstrate that the observed zero-bias conductance peak (ZBCP) is composed of Andreev bound states (ABS) which intrinsically form at a symmetry-breaking interface of an unconventional superconductor, for example, a (110)-surface of d-wave YBCO. Tunneling into doped or ion-damaged YBCO provides a measure of the QP scattering rate below T _c. An applied field causes Doppler shift of the ABS, arising from the scalar product between the QP velocity and the superfluid momentum, v _F·P _s, observed as a splitting in the ZBCP. Magnetic hysteresis of the splitting is consistent with the effects of strong vortex pinning near the interface. The directional field dependence shows that the ABS is highly anisotropic in its transport. These results, plus in-plane crystallographic orientational dependence on single-crystal BSCCO, demonstrate the d-wave symmetry of this superconductor. Below 8 K and in zero applied field, the ZBCP splits, indicating a transition into a superconducting state with spontaneously broken time-reversal symmetry (BTRS). EPR experiments are used to detect directly the spontaneous formation of the magnetic moments in the BTRS state.     

As failures mount: Affective and cognitive consequences of ability demotion in the classroom.

Hypothesized that reduced plausibility of explanations, such as insufficient study, lead to increasing self-attributions to inability that in turn mediate shame and lowered expectancies for future success. 339 undergraduates were administered a series of tests and the Michigan State Self-Concept of Ability Scale. Ss who experienced successive subjective failure gave postdictive explanations for each failure, indicated degree of shame, and rated expectancy for future success. Ss experiencing belated success after an initial failure were also examined. Path analysis confirmed self-worth predictions and suggested that despair observed in the learned helplessness paradigm occurred not so much from the noncontingent reinforcement of effort as from Ss' failure to protect a sense of personal competency. (65 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"I knew it cold before the exam": A test of the anxiety-blockage hypothesis.

Following a midterm exam in an introductory psychology course, college students (N?=?189) were administered the same test items under nonevaluative conditions. The hypothesis that high-anxious individuals as compared with low-anxious individuals would retrieve a greater degree of information not previously available to them when they were assessed under reduced threat was only partially supported. However, easy-item performance provided some evidence for an interference phenomenon. An interaction indicated that previously blocked information became available only for those high-anxious students who had initially used effective study strategies. Path analysis confirmed the relative importance of anxiety phenomena to classroom test performance in a time-ordered causal network involving ability level, study effectiveness, and anxiety arousal. Results add credence to a recent interpretation of anxiety as a failure-of-self phenomenon. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of 5-fluorouracil pharmacokinetics in patients receiving continuous 5-fluorouracil infusion and oral uracil plus N1-(2''-tetrahydrofuryl)-5-fluorouracil

In order to examine the relationship between long-term potentiation (LTP) and phosphoinositide (PI) turnover, we evaluated these throughout anesthetized rat brain using carbon-11-labeled diacylglycerol (11C-DAG). High-frequency tetanic stimulation (400 pulses at 400 Hz) to the perforant pathway induced LTP in rat dentate gyrus. In autoradiograms of rat brains, LTP was associated with the occurrence of multiple highly radioactive spots in many regions distant from the stimulated site. Following i.v. administration of an NMDA receptor antagonist prior to stimulation, however, no high-density spots were found. These findings directly demonstrate that potentiation of phosphoinositide-derived signaling was induced during LTP, and the finding of multiple location suggests the occurrence of polysynaptic neurotransmission through neural networks pertaining to learning and memory.     

Factors affecting number of prenatal care visits during second pregnancy among adolescents having rapid repeat births

PURPOSE: To examine factors associated with the number of prenatal care visits during second pregnancy for adolescents having a short interval between pregnancies. METHODS: The sample includes all adolescents aged 13 to 17 years whose first pregnancy resulted in a birth at a regional medical center in southeastern North Carolina from January 1983 to December 1989 and who had a repeat pregnancy within 24 months which resulted in a birth. We abstracted data from medical records and birth certificates. We fit a negative binomial regression model to determine the effects of various factors on the number of prenatal care visits during second pregnancy. RESULTS: The number of prenatal care visits during the first pregnancy, poor first birth outcome, interval between first and second pregnancy, and care provided by health department staff during first pregnancy were all positively associated with number of prenatal care visits during second pregnancy when controlling for gestation age of second birth. Other independent variables in the model included maternal age, education, black race, and being unmarried at the time of second birth. CONCLUSIONS: Because prenatal care is important for healthy mothers and babies, adolescents should be encouraged to seek prenatal care early in the first pregnancy. This could be an important time to implement interventions aimed at increasing prenatal care utilization in this and subsequent pregnancies.     

Women's oral health issues: an exploration of the literature

As interest in women's health issues grows, there is increasing concern that today's practice of medicine may not meet the health needs of women. A primary reason is the gender bias that has been inherent in medical education, research and clinical practice. The prevailing medical viewpoint has often been that the male body is considered to be the norm and that the female body exactly the same except for the reproductive function. This attitude has led to a lack of interest in researching gender differences and a consequent lack of knowledge of women's health issues. Fortunately, there is a movement for change. The Women's Health Interschool Curriculum Committee was formed in January 1992 to develop curricula concerning women's health and examine bias that may exist in existing curricula. The Canadian Women's Health Network has been growing across the country and there have been calls to create a new specialty in women's health. According to Angell, this proposal for a new specialty was provocatively debated in the Journal of Women's Health, which started publication in 1992. There is also a growing concern on how to conduct better research to address women's health needs. As more attention is paid to women's health issues, what will happen in the area of oral health? In health care, it would seem that the mouth has become completely separated from the rest of the body. Health conferences rarely have any oral health content at all. To correct this problem, there must be an increase in general awareness of the importance of oral health as it relates to the overall health of both women and men. Good oral health is more than just decay-free teeth. Oral health encompasses the teeth, the supporting periodontal structures, soft tissues of the mouth and oral pharynx area, temporomandibular joints and muscles of mastication. The mouth is a gateway to the body and will also reflect many systemic health problems, such as diabetes, leukemia and lupus. The second step would be the recognition that women may have different oral health needs and issues than men. The common view may be that teeth are gender free, but how can this be when teeth exist in a body, and that body is male or female? For many years, the primary acknowledged difference between men and women's oral health was pregnancy gingivitis. Like medicine, dentistry must re-examine the viewpoint that women's oral health differs from men's only as it is influenced by reproductive processes. There are many areas where women's oral health may differ from that of men. This paper will explore the literature for potential women's oral health issues in the areas of oral hygiene behaviours, esthetics, eating disorders, temporomandibular disorders, and hormonal influences on periodontal health.     

It's best to be able and virtuous too: Student and teacher evaluative responses to successful effort.

Although preferred student explanations for failure (high ability/low effort) lead to a conflict in student–teacher values, self-worth theory predicts that high effort is a shared value in success, since it poses no threat to the student's sense of competency. To test this assertion, 360 undergraduates rated their affective reactions to hypothetical test performances under 4 conditions of success. Then, in the role of teachers, they administered rewards to hypothetical students under identical conditions. Results indicate that both positive self-evaluation and teacher praise were greatest when success followed much effort. Conversely, both student pride and teacher reward were reduced when conditions of success detracted from the causal role of effort. Not only effort but also perceptions of ability enhanced positive affect. Consequently, students preferred to be seen as both able and motivated. (59 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)