Exact dynamic properties of molecular motors.

Molecular motors play important roles within a biological cell, performing functions such as intracellular transport and gene transcription. Recent experimental work suggests that there are many plausible biochemical mechanisms that molecules such as myosin-V could use to achieve motion. To account for the abundance of possible discrete-stochastic frameworks that can arise when modeling molecular motor walks, a generalized and straightforward graphical method for calculating their dynamic properties is presented. It allows the calculation of the velocity, dispersion, and randomness ratio for any proposed system through analysis of its structure. This article extends work of King and Altman ["A schematic method of deriving the rate laws of enzyme-catalyzed reactions," J. Phys. Chem. 60, 1375-1378 (1956)] on networks of enzymatic reactions by calculating additional dynamic properties for spatially hopping systems. Results for n-state systems are presented: single chain, parallel pathway, divided pathway, and divided pathway with a chain. A novel technique for combining multiple system architectures coupled at a reference state is also demonstrated. Four-state examples illustrate the effectiveness and simplicity of these methods.

Famine as agricultural catastrophe: the crisis of 1622-4 in east Lancashire.

This article argues that historians have paid insufficient attention to the agrarian roots of early modern English famines. While not dismissing the insights arising from entitlements theory, the article takes issue with recent writings that have explained the famine of 1622­3 in north-west England as an entitlements crisis. It offers new empirical evidence from an estate in east Lancashire to demonstrate the scale of the crisis in the early 1620s, using estate accounts to produce new price data and estimates of productivity. On the basis of oat tithe data, the scale of the shortfall in foodstuffs in the harvest of 1621 is demonstrated as being probably in the region of a third; that of the following year has to be inferred from price data. The evidence shows that the crisis was not limited to the arable economy, but was followed by an extensive restocking of the pastoral economy. The article therefore makes a contribution to the growing interest in weather as an exogenous factor.

Pleural decompression and drainage during trauma reception and resuscitation.

This review examines pleural decompression and drainage during initial hospital adult trauma reception and resuscitation, when it is indicated for haemodynamically unstable patients with signs of pneumothorax or haemothorax. The relevant historical background, techniques, complications and current controversies are highlighted. Key findings of this review are that: 1. Needle thoracocentesis is an unreliable means of decompressing the chest of an unstable patient and should only be used as a technique of last resort. 2. Blunt dissection and digital decompression through the pleura is the essential first step for pleural decompression, as decompression of the pleural space is a primary goal during reception of the haemodynamically unstable patient with a haemothorax or pneumothorax. Drainage and insertion of a chest tube is a secondary priority. 3. Techniques to prevent tube thoracostomy (TT) complications include aseptic technique, avoidance of trocars, digital exploration of the insertion site and guidance of the tube posteriorly and superiorly during insertion. 4. Whenever possible, blunt thoracic trauma patients should undergo definitive CT imaging after TT to check for appropriate tube position.

Creating micro and nano structures in polymers by moulding.

Moulding micro and nano surface features and discrete micro components in polymers reproducibly and in large volumes is now possible. The factors involved in successful micro injection moulding operations, including component size, aspect ratio and surface area, are examined.

Picosecond laser machining.

Laser machining technology can be used to create micro features and discrete parts of a few microns in size in any material. The latest technology and its capabilities are described.

Application of chemical shift imaging for measurement of NAA in head injured patients.

Neurochemical damage following brain injury can be assessed non-invasively by measurement of N-Acetyl-Aspartate (NAA) using Proton Magnetic Resonance Spectroscopy (1HMRS). This report documents results of applying Chemical Shift Imaging (CSI) postprocessing for measuring NAA in traumatically injured brain. Following stabilization, severely head-injured patients (GCS 8 or less) were transported to the MRI suite. Semi-quantitative measurement of NAA, creatine (Cr/PCr) and choline (Cho) were obtained from single voxels (8 cm3) and CSI for acquisition of smaller voxels (2 cm3) throughout areas of the brain. Studies were completed with no complication. In focal injury, SVS positioned at the site of lesion demonstrated reduced NAA, compared to contralateral hemisphere. In diffuse injury, CSI demonstrated uniform reduction of NAA throughout the brain. NAA/Cho showed normal levels within 24 hours of injury averaging 2.4 and decreased over the next 10 days reaching a plateau of 0.75. At 30 days, NAA showed no recovery in poor outcome patients. In patients with good outcome, NAA initially low recovered near baseline levels. CSI provides a comprehensive neurochemical assessment of neuronal damage. NAA decreases and remains low in patients with poor outcome. NAA recovers in patients with favorable outcome, suggesting marginal metabolic impairment and possible re-synthesis of the NAA pool.

Balkans briefing number 7. Pristina Hospital: under new management.

This is the seventh paper in a series on the consequences for public health of the conflict in the Balkans. It describes the state of the hospital sevices in Pristina after the cease fire in June 1999 and the subsequent reconstruction programme.

Evaluation of the All Stars character education and problem behavior prevention program: effects on mediator and outcome variables for middle school students.

The effects of All Stars, a character education and problem behavior prevention program, on variables theorized to mediate problem behaviors and on the problem behavior variables of substance use, sexual behavior, and violence among middle school students are reported. In an independent, randomized, single-cohort, longitudinal evaluation of the program, 1,655 students completed pretest, posttest, and 1-year follow-up surveys measuring demographics, mediating variables, and behavioral outcome variables. Results indicate that the All Stars program, when administered by teachers, had an immediate effect on mediating variables that did not persist over time. Inclusion of ethnicity in the design showed that the program, when administered by specialists, had delayed effects on mediating variables for African American and Hispanic students. However, no consistent effects were found for student problem behaviors in either condition. Implications for prevention practice and directions for future research are discussed.

Television campaigns and adolescent marijuana use: tests of sensation seeking targeting.

OBJECTIVES: This study evaluated the effectiveness of targeted televised public service announcement campaigns in reducing marijuana use among high-sensation-seeking adolescents. METHODS: The study used a controlled interrupted time-series design in 2 matched communities. Two televised antimarijuana campaigns were conducted in 1 county and 1 campaign in the comparison community. Personal interviews were conducted with 100 randomly selected teenagers monthly in each county for 32 months. RESULTS: All 3 campaigns reversed upward developmental trends in 30-day marijuana use among high-sensation seekers (P < .002). As expected, low-sensation seekers had low use levels, and no campaign effects were evident. CONCLUSIONS: Televised campaigns with high reach and frequency that use public service announcements designed for and targeted at high-sensation-seeking adolescents can significantly reduce substance use in this high-risk population.

Personality and sexual risk taking: a quantitative review.

Findings from a quantitative review of the empirical research literature on normal personality and sexual risk taking are reported. The review focuses on domains identified in major models of normal personality representing the psychobiological and taxonomic perspectives. Focal sexual risk-taking behaviors were number of partners, unprotected sex, and high-risk sexual encounters (e.g., sex with a stranger). A comprehensive search produced 53 studies relevant to the review. A striking feature of the results is the paucity of research on domains of normal personality and sexual risk taking for all domains other than sensation seeking, which accounted for 64% of the effect sizes. The preponderance of studies (81%) took the psychobiological perspective and were published since 1990 (75%). Among the substantive findings were effects for sensation seeking, impulsivity, and agreeableness on all sexual risk-taking behaviors considered. Additionally, there were effects on specific behaviors for neuroticism and conscientiousness. The implications of these findings for future research on normal personality and sexual risk taking are discussed.

Personality processes and problem behavior.

This article introduces the special issue of Journal of Personality on personality and problem behavior. There is growing evidence that various dimensions of personality are associated with a broad range of problem behaviors such as drug and alcohol use, sexual risk-taking, interpersonal violence, and gambling. To date, research on personality and problem behavior has focused almost exclusively on documenting simple, direct associations between personality traits and problem behaviors. This article proposes an expanded research agenda, a second generation of research and theory on the role of personality in problem behavior. The agenda specifies two major classes of second-generation hypotheses. Moderator hypotheses concern the conditions under which the influence of personality on problem behavior is magnified, weakened, or eliminated. Mediator hypotheses concern the causal processes that underlie the influence of personality on problem behavior. Articles in the special issue, which are summarized in this introduction, exemplify the proposed second generation of research on personality and problem behavior.

Sensation seeking and drug use by adolescents and their friends: models for marijuana and alcohol.

OBJECTIVE: To investigate the prospective influence of individual adolescents' sensation seeking tendency and the sensation seeking tendency of named peers on the use of alcohol and marijuana, controlling for a variety of interpersonal and attitudinal risk and protective factors. METHOD: Data were collected from a cohort of adolescents (N = 428; 60% female) at three points in time, starting in the eighth grade. Respondents provided information about sensation seeking, the positivity of family relations, attitudes toward alcohol and drug use, perceptions of their friends' use of alcohol and marijuana, perceptions of influence by their friends to use alcohol and marijuana, and their own use of alcohol and marijuana. In addition, they named up to three peers, whose sensation seeking and use data were integrated with respondents' data to allow for tests of hypotheses about peer clustering and substance use. RESULTS: Structural equation modeling analyses revealed direct effects of peers' sensation seeking on adolescents' own use of both marijuana and alcohol 2 years later. An unexpected finding was that the individual's own sensation seeking had indirect (not direct) effects on drug use 2 years later. CONCLUSIONS: These findings indicate the potential importance of sensation seeking as a characteristic on which adolescent peers cluster. Furthermore, the findings indicate that, beyond the influence of a variety of other risk factors, peer sensation seeking contributes to adolescents' substance use.