Synthesizing verified components for cyber assured systems engineering

Software and Systems Modeling - Safety-critical systems such as avionics need to be engineered to be cyber resilient meaning that systems are able to detect and recover from attacks or safely...     

Random preferences towards bioenergy environmental externalities: A case study of woody biomass based electricity in the Southern United States

This paper contrasts alternate methodological approaches of investigating public preferences, the random parameter logit (RPL) where tastes and preferences of respondents are assumed to be heterogeneous and the conditional logit (CL) approach where tastes and preferences remain fixed for individuals. We conducted a choice experiment to assess preferences for woody biomass based electricity in Arkansas, Florida, and Virginia. Reduction of CO₂ emissions and improvement of forest habitat by decreasing risk of wildfires and pest outbreaks were presented to respondents as attributes of using green electricity. The results indicate that heterogeneous preferences might be a better fit for assessing preferences for green electricity. All levels of both attributes were positive contributors to welfare but they were no statistically significant. Respondents expressed a positive mean marginal willingness to pay (WTP) for each attribute level. The total WTP for green electricity per kilowatt hour was $0.049 kWh or $40.5 per capita year^{− 1} when converted into future total annual expenditures.     

The concept of psychological regression: Metaphors, mapping, Queen Square, and Tavistock Square.

The term “regression” refers to events in which an individual changes from his or her present level of maturity and regains mental and behavioral characteristics shown at an earlier point in development. This definition has remained constant for over a century, but the implications of the concept have changed systematically from a perspective in which regression was considered pathological, to a current view in which regression may be seen as a positive step in psychotherapy or as a part of normal development. The concept of regression, famously employed by Sigmund Freud and others in his circle, derived from ideas suggested by Herbert Spencer and by John Hughlings Jackson. By the 1940s and '50s, the regression concept was applied by Winnicott and others in treatment of disturbed children and in adult psychotherapy. In addition, behavioral regression came to be seen as a part of a normal developmental trajectory, with a focus on expectable variability. The present article examines historical changes in the regression concept in terms of mapping to biomedical or other metaphors, in terms of a movement from earlier nativism toward an increased environmentalism in psychology, and with respect to other historical factors such as wartime events. The role of dominant metaphors in shifting perspectives on regression is described. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Alkalinity generation and metals retention in a successive alkalinity producing system

Alkalinity generation and metals retention were evaluated during the initial year of operation of a treatment wetland, consisting of four 185 m² inseries cells comprised of alternating vertical-flow anaerobic substrate wetlands (VFs) and surface-flow aerobic settling ponds (SFs). The substrate in the VFs consists of spent mushroom substrate (SMS) and limestone gravel, supplemented with hydrated fly ash in a 20∶10∶1 ratio by volume. Approximately 15±4 L/min of acid mine drainage (AMD) from an abandoned underground coal mine in southeastern Oklahoma, USA, was directed to the system in October 1998 (mean influent water quality: 660 mg L⁻¹ net acidity as CaCO₃ eq., pH 3.4, 215 mg L⁻¹ total Fe, 36 mg L⁻¹ Al, 14 mg L⁻¹ Mn, and 1000 mg L⁻¹ SO₄ ⁻²). Flow through the first VF resulted in substantial increases in alkalinity, decreased metal concentrations and circumneutral pH. 258±84 mg L⁻¹ of alkalinity was produced in the first VF by a combination of processes. Final discharge waters were net alkaline on all sampling dates (mean net alkalinity=136 mg L⁻¹). Total Fe and Al concentrations decreased significantly from 216±45 to 44±28 mg L⁻¹ and 36±6.9 to 1.29±4.4 mg L⁻¹, respectively. Manganese concentrations did not change significantly in the first two cells, but decreased significantly in the second two cells. Mean acidity removal rates in the first VF (51 g m⁻² day⁻¹) were similar to those previously reported.     

Assessing the Floristic Diversity of Hedge Networks: A landscape perspective

The type of land cover adjacent to hedges has been shown to influence the species composition of the ground flora. An assessment of the contribution of hedge networks to the biodiversity of landscapes therefore requires information on the relative lengths of hedge associated with different land covers. In the River Tyne catchment, Northern England, the association between hedges and land cover types differed between four landscapes. Overall, the greatest length of hedge was adjacent to arable crops, improved grasslands and roads. Hedges next to improved grassland and roads were the most species-rich, while those adjacent to arable crops were the least species-rich. Species which were common adjacent to arable crops were also common adjacent to other land covers. Hedges adjacent to improved grassland, roads and semi-natural broadleaved woodland supported species which were not common elsewhere in the hedge network. It was also found that hedges with different land cover on each side supported different floras on each side. When planning landscape-scale surveys of hedge biodiversity, it is important to survey both sides of hedges, and sampling should be stratified to include hedges adjacent to the different types of land cover present.     

A statistical model for delay-fault testing

The authors propose a statistical model for measuring delay-fault coverage. The model provides a figure of merit for delay testing in the same way that fault coverage provides one for the testing of single stuck-at faults. The mode measures test effectiveness in terms of the propagation delay of the path to be tested, the size of the delay defect, and the system clock interval, and then combines the data for all delay faults to measure total delay-fault coverage. The authors also propose a model for measuring the defect level as a function of the manufacturing yield and the predictions of the statistical delay-fault coverage model     

The relationship between cholecystectomy, unoperated gallstone disease, and colorectal cancer. A necropsy study

BACKGROUND: There may be an increased risk of colorectal cancer after cholecystectomy, but the literature is not consistent. It is also possible that any risk might be associated with gallstones rather than cholecystectomy. METHODS: In a prospective necropsy study of 8563 cases, all 219 cases of a previous cholecystectomy were pair-matched to subjects with gallstones and to subjects with a normal gallbladder. In a second study all 192 cases of colorectal cancer were pair-matched to cancer-free subjects. RESULTS: The odds ratio (OR) for developing colorectal cancer after cholecystectomy compared with a normal gallbladder was 1.0 (95% confidence interval, 0.30-3.34) and with unoperated gallstones was 0.88 (0.27-2.76). CONCLUSIONS: This study fails to support an association between cholecystectomy or gallstones and colorectal cancer. For those cases of colorectal cancer versus controls, the OR for previous cholecystectomy was 0.70 (0.23-2.04) and for gallstone disease was 0.93 (0.58-1.48).     

Effects of methylphenidate on preschool children with ADHD: cognitive and behavioral functions

OBJECTIVE: To report on implications for methylphenidate treatment of this very young age group and the need to examine factors related to achieving compliance. METHOD: Thirty-one children with attention-deficit hyperactivity disorder (ADHD), aged 4 to 6 years, participated in a double-blind, placebo-controlled study using placebo, 0.3 mg/kg, and 0.5 mg/kg of methylphenidate twice per day. RESULTS: Improvements related to medication were obtained on cognitive tests of attention and impulsivity as well as behaviors assessed by parent rating scales. In an interactive setting with their mothers, attentional abilities and the children's ability to work more productively also showed improvement. However, no changes were obtained with respect to the children's tendency to comply with parental requests. Side effects increased slightly with the high dosage of medication but remained mild. CONCLUSION: The results suggest that methylphenidate can be used to improve the functioning of preschool-age children with ADHD, in a manner similar to their school-age counterparts.