bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of diffraction by ionospheric electron density irregularities on the range error in GNSS dual‐frequency positioning and phase decorrelation
Authors: Gherm Vadim E. , Zernov Nikolay N. , Strangeways Hal J.
Published: June 2011

It can be important to determine the correlation of different frequency signals in L band that have followed transionospheric paths. In the future, both GPS and the new Galileo satellite system will broadcast three frequencies enabling more advanced three frequency correction schemes so that knowledge of correlations of different frequency pairs for scintillation conditions is desirable. Even at present, it would be helpful to know how dual‐frequency Global Navigation Satellite Systems positioning can be affected by lack of correlation between the L1 and L2 signals. To treat this problem of signal correlation for the case of strong scintillation, a previously constructed simulator program, based on the hybrid method, has been further modified to simulate the fields for both frequencies on the ground, taking account of their cross correlation. Then, the errors in the two‐frequency range finding method caused by scintillation have been estimated for particular ionospheric conditions and for a realistic fully three‐dimensional model of the ionospheric turbulence. The results which are presented for five different frequency pairs (L1/L2, L1/L3, L1/L5, L2/L3, and L2/L5) show the dependence of diffractional errors on the scintillation index S4 and that the errors diverge from a linear relationship, the stronger are scintillation effects, and may reach up to ten centimeters, or more. The correlation of the phases at spaced frequencies has also been studied and found that the correlation coefficients for different pairs of frequencies depend on the procedure of phase retrieval, and reduce slowly as both the variance of the electron density fluctuations and cycle slips increase.
A theory of non-local linear drift wave transport
Authors: Moradi S. , Anderson J. , Weyssow B.
Published: June 2011

Transport events in turbulent tokamak plasmas often exhibit non-local or non-diffusive action at a distance features that so far have eluded a conclusive theoretical description. In this paper a theory of non-local transport is investigated through a Fokker-Planck equation with fractional velocity derivatives. A dispersion relation for density gradient driven linear drift modes is derived including the effects of the fractional velocity derivative in the Fokker-Planck equation. It is found that a small deviation (a few percent) from the Maxwellian distribution function alters the dispersion relation such that the growth rates are substantially increased and thereby may cause enhanced levels of transport.
A numerical study of the sodium vapor discharge plasma
Authors: Ben Ahmed R. , Araoud Z. , Charrada K.
Published: June 2011

In this article we will discuss, in detail, the results obtained for a simple geometry of discharge (two-dimensional stationary or one-dimensional non stationary). It aims to give an idea about the discharge properties that emerge from the interaction of various physical processes. By using a variation of the fundamental parameters, we can show the capacity of the model to reproduce all the macroscopic properties of plasma discharge in sodium vapor. The validation of the model will be discussed and some comparisons with the existing experimental data will be presented.
Germination characteristics of tropical and sub-tropical rangeland species
Authors: McIvor John G. , Reid David J.
Published: June 2011

A study was made of the germination characteristics of a broad spectrum of rangeland species by studying their behaviour under different conditions. Seeds of common species (both native and exotic) were collected from tropical (north-east Queensland) (36 species) and sub-tropical areas (south-east Queensland) (47 species). The seeds were exposed to three storage treatments: in a shade-house for 60 months, in a seed store (tropical collection) or freezer (sub-tropical collection) for 60 months, or in an oven with fluctuating temperatures (25/60°C) for 3 (tropical collection) or 4 (sub-tropical collection) months. Germination was tested during and after storage under standard conditions of 30/25°C (tropical collection) or 30/20°C (sub-tropical collection) with light during the 12-h period of higher temperature. In addition, germination of the sub-tropical collection was tested in the dark and at lower temperature (20/10°C). The species were divided into groups on the basis of changes in germination during storage in a shade-house or in a seed store or freezer. The species showed a wide range of germination behaviour, changes during storage, and responses to germination conditions. Differences in the responses of seed lots of the same species in the two collections show that care is needed when extrapolating results from one experiment to other collections and regions.
Beyond cattle: potential futures of the pastoral industry in the Northern Territory
Authors: Puig C. J. , Greiner R. , Huchery C. , Perkins I. , Bowen L. , Collier N. , Garnett S. T.
Published: June 2011

The pastoral industry of the Northern Territory faces a suite of environmental and economic challenges associated with, inter alia, export markets, costs of production, climate change, change in government policies, and potential cattle diseases. A participatory planning process was adopted by the industry’s principal representative body, the Northern Territory Cattlemen’s Association to explore the complexity and extent of possible impacts on the industry, and to initiate conversations about anticipating potential futures. The process was facilitated by a system dynamics model, named the Pastoral Properties Future Simulator (PPFS). The PPFS combined a systems modelling approach of the pastoral industry with scenario explorations to gauge the likely impacts on, and possible industry adaptations to, beef price variation, productivity improvements, diversification of land use, climate change, climate policy and employment. The PPFS was used as an interactive tool during stakeholder workshops and results underpinned discussions about impacts and adaptation strategies. Land use and enterprise diversification emerged as key strategies for building enterprise and industry resilience, but with regionally diverging emphasis. The research illustrates the benefits of applied systems dynamic modelling for participatory strategic planning in the face of an uncertain future. The PPFS helped industry members and stakeholders understand the complexity of drivers affecting the industry’s future, risk profiles, possible adaptation strategies and trade-offs.
Health and behaviour consequences of feral horse relocation
Authors: Hampson B. A. , Zabek M. A. , Pollitt C. C. , Nock B.
Published: June 2011

Despite ongoing projects involving the breeding and release of equids into semi-wild and wild environments, insufficient information is available in the literature that describes strategies used by equids to adapt and survive in a novel environment. The aim of this study was to assess the ability of naïve, feral Equus caballus (horse) mares to cope in a novel feral horse environment and investigate possible reasons why some may not survive this challenge. Four mares taken from a semi-arid desert environment remained in good health but significantly changed their movement behaviour pattern when surrounded by prime grazing habitat in a mesic temperate grassland. Three of the four mares captured from the prime grazing habitat and released in the semi-arid desert habitat died, apparently due to stress and/or starvation, within 8 weeks of release. The fourth mare survived 4 months but lost considerable weight. The group of mares relocated to the semi-arid desert environment had difficulty adapting to relocation and did not take up the movement behaviour strategy of local horses, which required long distance treks from a central water hole to distant feeding areas at least 15 km away. The movement behaviour, range use and health consequences of relocating equids may be of interest to wildlife ecologists, animal behaviourists and horse welfare groups. The observations may be used to guide those intending on relocating managed domestic and native horses to novel habitats.
Using geomorphology to assess contour furrowing in western New South Wales, Australia
Authors: Wakelin-King Gresley
Published: June 2011

This study examines landscape rehabilitation treatments installed 20–40 years ago in the Western Catchment of NSW. Treatment outcomes were assessed using geomorphic criteria, because geomorphic processes are fundamental to ecological permanence. Contour furrowing creates artificial runoff-runon sets which intercept runoff (resistance to flow by windrows microrelief and surface roughness) and promote infiltration (artificial permeability by ripping). As originally conceived, after windrows subside, flow resistance would be afforded by surface roughness under belts of vegetation. This study shows that rehabilitation treatments have a more complex relationship with the landscape than this would suggest, and that the final effect of the treatment depends on the geomorphic processes natural to the site. Treatment design should therefore be site-specific. The relevant aspects of treatment design are site location, runoff : runon ratio (expressed as furrow spacing and furrow length), furrow placement, and post-treatment management. Some long-term successes are documented. In ironstone ridge country affected by impermeable hard-setting soils, furrowing creates artificial permeability, allowing plant germination; plant material in the soil reverses hard-setting and establishes self-sustaining permeability. In stony gilgai country furrowing through vegetated patches can aid in re-establishing vegetation, but furrowing through stony runoff patches only diminishes, rather than improves, landscape function. Other landscape types will have different key attributes. In all cases, selection of appropriate sites for rehabilitation treatment is of primary importance. The 1990s NSW Soil Conservation Service best-practice included a specialised furrower, surveying techniques for accurate furrow placement along the contour, staggered gaps along each furrow line to reduce risks of gullying by windrow breakthrough, and post-treatment management of total grazing pressure. New guidelines for treatment design developed from this study include determining for each site the optimum runoff:runon ratio (which varies according to climate, gradient, vegetation, and regolith), and matching furrow spacing and furrow/gap length to local runoff:runon ratios. In stony gilgai country, furrow placement should be along the contour but within non-stony patches; elsewhere, placement should be rigorously along the contour. In ironstone ridge country, a greater runoff:runon ratio, commensurate with the area’s apparently larger patch scale, can be achieved by having more gap than furrow along each furrow line. No single rehabilitation technique will fit all landscape types, and these guidelines will ideally be developed further with investigation of other landscapes.
Measuring human papillomavirus (HPV) vaccination coverage and the role of the National HPV Vaccination Program Register, Australia
Authors: Gertig Dorota M. , Brotherton Julia M. L. , Saville Marion
Published: June 2011

Accurate estimates of HPV vaccination coverage are critical for determining the proportion of the target female population that is not protected by the vaccine, as well as for monitoring the performance of vaccine delivery programs. The implementation of an HPV vaccination register, either as part of an existing immunisation register or stand-alone, can add substantial benefits to an HPV vaccination program. In Australia, the National HPV Vaccination Program Register supports the HPV vaccination program by providing information to consumers and providers about incomplete courses as well as estimates of vaccination coverage by age and area. Future monitoring of vaccine effectiveness will be facilitated by cross-linking to Pap test registries.
HIV serosorting among HIV-positive men who have sex with men is associated with increased self-reported incidence of bacterial sexually transmissible infections
Authors: Marcus Ulrich , Schmidt Axel J. , Hamouda Osamah
Published: June 2011

Background: We aimed to quantify the frequency of HIV serosorting among men who have sex with men (MSM) in Germany, and evaluate the association of serosorting with other sexual risk management approaches (RMA) and with the frequency of bacterial sexually transmissible infections (STI). Methods: An anonymous, self-administered questionnaire was distributed through German online sexual networking sites and medical practices in 2006. The analysis was based on 2985 respondents who reported an HIV test result. Based on two questions on RMA, serosorting was classified as tactical (an event-based decision) or strategic (a premeditated search for a seroconcordant partner). The analysis was stratified by HIV serostatus and seroconcordant partnership status. Results: HIV serosorting patterns were different for HIV-positive and HIV-negative participants. Tactical serosorting ranked second after RMA based on condom use (HIV-positive: 55.1%, HIV-negative: 45.1%; P < 0.001). While the overlap of strategic and tactical HIV serosorting among HIV-positive MSM was substantial (58.0%), HIV-negative strategic and tactical serosorting were more distinct (18.1% overlap). Among HIV-positive and HIV-negative respondents, tactical serosorting was associated with reduced condom use. Compared with respondents using RMA other than serosorting, HIV-positive men reporting serosorting had a three-fold increased risk for bacterial STI (strategic: odds ratio (OR) = 2.62; 95% confidence interval (CI): 1.76–3.89; tactical: OR = 3.19; 95% CI: 2.14–4.75; both for respondents without HIV seroconcordant partners). Conclusions: HIV serosorting has emerged as a common RMA among MSM. For HIV-positive MSM, it may contribute to high rates of bacterial STI that may lead to elevated per-contact risks for HIV transmission.
Symptomatic and asymptomatic early neurosyphilis in HIV-infected men who have sex with men: a retrospective case series from 2000 to 2007
Authors: Chang Christina C. , Leslie David E. , Spelman Denis , Chua Kyra , Fairley Christopher K. , Street Alan , Crowe Suzanne M. , Hoy Jennifer F.
Published: June 2011

Background The rise in serious complications of early syphilis, including neurosyphilis, particularly in those with HIV infection and in men who have sex with men (MSM), is of concern. Objectives: To review the manifestations and management of neurosyphilis in a population of HIV-infected MSM. Methods: Retrospective review of patients with HIV and early neurosyphilis in three centres in Melbourne, Australia, in 2000–07. Results: Eighteen male HIV patients met the criteria for diagnosis of early neurosyphilis. Thirteen patients (72.2%) had neurological symptoms: six with headache (33.3%), four with tinnitus (22.2%) and five with impaired vision (27.8%), and one patient each with ataxia, leg weakness and anal discharge with faecal incontinence. Five patients (27.8%) reported no neurological symptoms. All had serum rapid plasma reagin (RPR) titres ≥1 : 32 and all except one had cerebrospinal fluid positive for syphilis fluorescent treponemal antibodies-absorbed. After treatment with 14–15 days of 1.8 g intravenous benzylpenicillin 4-hourly, 12 of 17 patients (71%) demonstrated a four-fold drop in serum RPR titre over 6–12 months and were considered successfully treated. A rise in RPR was noted in three patients during the 12-month follow-up period, suggesting re-infection or recurrence. Conclusion: HIV-infected patients found to have syphilis either because of symptoms or by routine screening should be carefully assessed for neurological, ophthalmic and otological symptoms and signs. A low threshold for a diagnostic lumbar puncture to exclude the diagnosis of neurosyphilis enables appropriate administration and dose of penicillin for treatment, which appears successful in ~75% of cases.
HIV seroconversions among male non-occupational post-exposure prophylaxis service users: a data linkage study
Authors: Pierce Anna B. , Yohannes Keflemariam , Guy Rebecca , Watson Kerrie M. , Armishaw Jude , Price Brian , Hoy Jennifer F. , Wright Edwina J. , Stoové Mark A.
Published: June 2011

Background: Despite widespread prescription of non-occupational post-exposure prophylaxis (NPEP) in Victoria, little is known about subsequent HIV acquisition among NPEP users. We linked the Victorian NPEP Service (VNPEPS) database and the Victorian HIV Surveillance Registry to determine the number, incidence rate and predictive factors of HIV seroconversions among users of the VNPEPS. Methods: Records from male patients that received NPEP in the VNPEPS database (n = 1420) between January 2001 and February 2008 were linked with all entries in the Victorian HIV Surveillance Registry up to May 2008. Results: Sixty-one men who presented to the VNPEPS were identified as HIV seropositive; 16 of these were diagnosed at initial presentation for NPEP. The incidence of HIV seroconversion in males who were HIV seronegative at first presentation for NPEP was 1.27 (95% confidence interval 0.95–1.70) per 100 person-years. There was no association between HIV seroconversion and number of NPEP presentations or age. The median age of seroconversion was 34.6 years. Conclusion: The incidence of HIV infection among men presenting to the VNPEPS is slightly lower than the HIV incidence in NPEP users in a recent Australian cohort study of men who have sex with men, but higher than HIV incidence in general gay male populations. Frequency of NPEP use was not associated with risk of HIV seroconversion. Examination of risk behaviour before and after NPEP use in this population is required to further assess the impact of NPEP availability and use on HIV incidence rates and risk behaviour in Australia.
Improving Chlamydia trachomatis retesting rates by mailed self-collection kit
Authors: Buhrer-Skinner Monika , Muller Reinhold , Buettner Petra G. , Gordon Rose , Debattista Joseph
Published: June 2011

Background
To assess a mailed self-collection kit for chlamydia testing as an intervention to increase post-treatment retesting rates. Methods: This prospective intervention study took place at a sexual health clinic in Townsville, North Queensland (Australia) between 2006 and 2008. The intervention consisted of offering to mail a self-collection kit for retesting 3 months after treatment. The achieved retesting rates were compared to those from the previous year and to concurrent controls who did not participate in the intervention. Both control groups received standard advice on retesting. Results: Of the 46 participants in the intervention group, 34.8% returned the sample for retesting 3 to 4 months after initial treatment, in comparison to 6.8% of the historic control groups (n = 206) and 1.4% of the concurrent control group (n = 142) (P < 0.001, respectively). Conclusions: Retesting rates for Chlamydia trachomatis were substantially and significantly improved using the mailed self-collection kit evidencing that the kit could deliver a much needed intervention to improve notoriously low retesting rates.
Impact evaluation of a youth sexually transmissible infection awareness campaign using routinely collected data sources
Authors: Gold Judy , Goller Jane , Hellard Margaret , Lim Megan S. C. , Hocking Jane , Fairley Christopher K. , Spelman Tim , McNamee Kathleen , Clift Philip , Guy Rebecca
Published: June 2011

Background Young people are at high risk of sexually transmissible infections (STI) and notifications of chlamydia are rising rapidly. In 2007, a Victorian multimedia campaign aimed to increase STI testing and condom use among 18–25-year-olds. We conducted a retrospective impact evaluation using multiple sources of routinely collected data. Methods: Population-level chlamydia testing data from general practice, chlamydia testing data from five government primary care clinics with a high caseload of young people, and behavioural data from an annual youth behavioural survey were analysed. Analyses included time-series regression to assess trends in testing levels, Kruskal–Wallis tests to assess changes in positivity, and χ2-tests to assess knowledge and behaviour change. Results: There was no significant difference in the slope of monthly chlamydia testing in population-level or clinic-based surveillance during the campaign compared with before or after the campaign, and no changes in chlamydia positivity. Between 2007 and 2008, there was a significant increase in STI knowledge among females (P < 0.01) and in the proportion of females reporting always using a condom with casual (P = 0.04) and new sexual partners (P < 0.01) in the annual behavioural survey. Conclusions: Our findings suggest the campaign had no impact on STI testing but may have contributed to an increase in knowledge and condom use among females; however, this increase could not be directly attributed to the campaign. Future campaigns targeting young people for STI testing should consider alternative messages and approaches, and include robust evaluation mechanisms to measure campaign impact prospectively.
Acceptability of female condom use in money boys compared with other men who have sex with men in Chengdu, China: a comparative study
Authors: Chen Bo , Zhang Ming , Yang Dou , Wang Xiaodong , Zheng Yi
Published: June 2011

We conducted a clinical trial to compare sexual behaviours and attitudes regarding female condoms among money boys and other men who have sex with men in Chengdu, China, with a particular focus on factors influencing use of female condoms.
Range contraction in large pelagic predators
Authors: Worm Boris , Tittensor Derek P.
Published: June 2011

Large reductions in the abundance of exploited land predators have led to significant range contractions for those species. This pattern can be formalized as the range–abundance relationship, a general macroecological pattern that has important implications for the conservation of threatened species. Here we ask whether similar responses may have occurred in highly mobile pelagic predators, specifically 13 species of tuna and billfish. We analyzed two multidecadal global data sets on the spatial distribution of catches and fishing effort targeting these species and compared these with available abundance time series from stock assessments. We calculated the effort needed to reliably detect the presence of a species and then computed observed range sizes in each decade from 1960 to 2000. Results suggest significant range contractions in 9 of the 13 species considered here (between 2% and 46% loss of observed range) and significant range expansions in two species (11–29% increase). Species that have undergone the largest declines in abundance and are of particular conservation concern tended to show the largest range contractions. These include all three species of bluefin tuna and several marlin species. In contrast, skipjack tuna, which may have increased its abundance in the Pacific, has also expanded its range size. These results mirror patterns described for many land predators, despite considerable differences in habitat, mobility, and dispersal, and imply ecological extirpation of heavily exploited species across parts of their range.
R-spondins function as ligands of the orphan receptors LGR4 and LGR5 to regulate Wnt/β-catenin signaling
Authors: Carmon Kendra S. , Gong Xing , Lin Qiushi , Thomas Anthony , Liu Qingyun
Published: June 2011

The Wnt/β-catenin signaling system plays essential roles in embryonic development and in the self-renewal and maintenance of adult stem cells. R-spondins (RSPOs) are a group of secreted proteins that enhance Wnt/β-catenin signaling and have pleiotropic functions in development and stem cell growth. LGR5, an orphan receptor of the G protein-coupled receptor (GPCR) superfamily, is specifically expressed in stem cells of the intestinal crypt and hair follicle. Knockout of LGR5 in the mouse results in neonatal lethality. LGR4, a receptor closely related to LGR5, also has essential roles in development, as its knockout leads to reduced viability and retarded growth. Overexpression of both receptors has been reported in several types of cancer. Here we demonstrate that LGR4 and LGR5 bind the R-spondins with high affinity and mediate the potentiation of Wnt/β-catenin signaling by enhancing Wnt-induced LRP6 phosphorylation. Interestingly, neither receptor is coupled to heterotrimeric G proteins or to β-arrestin when stimulated by the R-spondins, indicating a unique mechanism of action. The findings provide a basis for stem cell-specific effects of Wnt/β-catenin signaling and for the broad range of functions LGR4, LGR5, and the R-spondins have in normal and malignant growth.
In vitro system capable of differentiating fast Ca
2+
-triggered content mixing from lipid exchange for mechanistic studies of neurotransmitter release
Authors: Kyoung Minjoung , Srivastava Ankita , Zhang Yunxiang , Diao Jiajie , Vrljic Marija , Grob Patricia , Nogales Eva , Chu Steven , Brunger Axel T.
Published: June 2011

Understanding the molecular principles of synaptic vesicle fusion is a long-sought goal. It requires the development of a synthetic system that allows manipulations and observations not possible in vivo. Here, we report an in vitro system with reconstituted synaptic proteins that meets the long-sought goal to produce fast content release in the millisecond time regime upon Ca
2+
triggering. Our system simultaneously monitors both content and lipid exchange, and it starts from stable interacting pairs of donor and acceptor vesicles, mimicking the readily releasable pool of synaptic vesicles prior to an action potential. It differentiates between single-vesicle interaction, hemifusion, and complete fusion, the latter mimicking quantized neurotransmitter release upon exocytosis of synaptic vesicles. Prior to Ca
2+
injection, the system is in a state in which spontaneous fusion events between donor and acceptor vesicles are rare. Upon Ca
2+
injection, a rapid burst of complete fusion events emerges, followed by a biphasic decay. The present study focuses on neuronal SNAREs, the Ca
2+
sensor synaptotagmin 1, and the modulator complexin. However, other synaptic proteins could be added and their function examined. Ca
2+
triggering is cooperative, requiring the presence of synaptotagmin, whereas SNAREs alone do not produce a fast fusion burst. Manipulations of the system mimic effects observed in vivo. These results also show that neuronal SNAREs alone do not efficiently produce complete fusion, that the combination of SNAREs with synaptotagmin lowers the activation barriers to full fusion, and that complexin enhances this kinetic control.
The politics of agrofuels and mega-land and water deals: insights from the ProCana case, Mozambique
Authors: Borras Saturnino
                      M. , Fig David , Suárez Sofía
                      Monsalve
Published: June 2011

This paper examines the politics of large-scale commercial biofuels production and mega-land–water deals, with special reference to the dynamics of changes in land/water use and property rights and how these impact on the lives and livelihoods of the socio-economically marginalised rural sectors in the countryside. The main argument is that the assumption about existing, available marginal lands is fundamentally flawed. It is demonstrated by examining the ProCana sugar cane ethanol plantation in Gaza province in Mozambique.
Going back or going forward? Tensions in the formulation of a new National Curriculum in mathematics
Authors: Brown Margaret
Published: June 2011

Inferences from recent international comparative data on mathematical attainment, frequently quoted as justification for curriculum change, are critically examined, and the implications are contrasted with expressed curricular aims. Using characterisations by Ball (1990) and Ernest (1991), positions of key actors are analysed in relation to priorities given to different aspects of the mathematics curriculum, in particular facts and skills, cultural heritage, functionality and curricular structure. These are compared with characterisations made in the late 1980s, and in the early years of the New Labour government. This analysis highlights tensions that are likely to arise in the design of a new curriculum in mathematics.
Reviewing the National Curriculum for science: opportunities and challenges
Authors: Millar Robin
Published: June 2011

This article considers the extent to which the English National Curriculum for science has influenced practice and learning outcomes, and briefly reviews the mechanisms through which this influence is exerted. It identifies and discusses three central issues for the review that is now in progress: the structure of the science curriculum; the purpose of science within the school curriculum; and the way in which curriculum content is specified and communicated. It argues that the conflicting demands of breadth and depth need to be more authoritatively resolved, so that students beginning upper secondary school courses in the sciences do so on a more equal footing. It explores the curriculum consequences of the tension between the role of school science in improving the ‘scientific literacy’ of all young people and in providing a sound foundation for more advanced study for the important minority who so choose. Finally it explores the aspirations of the current review for a clear and succinct statement of curriculum content, arguing that clear communication of intended curriculum content requires that examples be provided showing how these might be operationalised, and for recognition of both the value and the limitations of evidence and theory to underpin decisions on sequencing of science curriculum content.
EDUCATION, SOCIAL ORIGINS AND CAREER (IM)MOBILITY IN CONTEMPORARY ITALY
Authors: Bison Ivano
Published: June 2011

Italy has always been characterized by low rates of career mobility. However, whilst the essential features of intragenerational (im)mobility in Italy are relatively well known, much less is known about the pattern of the specific paths linking the class of the first job with later class positions. To date, no studies of career mobility have been conducted in holistic terms; that is, based on examination of the entire sequence of the class positions occupied by an individual during his/her work history. This paper develops a typology of sequences of transition from one social class to another which preserves the qualitative differences among individual sequences. We introduce a new method to measure resemblance among sequences in order to identify the main career paths observable in Italy. We then examine how these profiles have changed over time because of transformations in the economic system and of the changing size of different social classes. Furthermore, we will try to determine whether and how social origins and education affect the probabilities of following those paths. The results show that social origins: 1) still influence the career patterns of younger cohorts); and 2) play a very important role in modifying the chances of highly-educated people to enter the upward career patterns leading to the service class or to white-collar positions.
OCCUPATIONAL ATTAINMENT AND CAREER PROGRESSION IN SWEDEN
Authors: Härkönen Juho , Bihagen Erik
Published: June 2011

We analyze occupational attainment and career progression over the life course for Swedish men and women, born in 1925–1974. Careers progress (measured as improvements in occupational prestige) fast during the first 5–10 years in the labour market, and flatten out afterwards (approximately between 30–40 years of age). This is in line with the occupational status maturation hypothesis. Both class origin and educational attainment affect occupational attainment. The effects of educational attainment vary more over the career, but depend on the educational attainment level in question. Successive cohorts of women gain higher occupational prestige, and continue to gain in occupational prestige longer across their careers. We also find that cohorts that entered the labour market in times of economic downturns and restructuring (the oil crisis years and the early 1990s) had more difficulties in establishing their careers. Returns to education generally increase across cohorts, while class background differences decrease, as has been reported in earlier research.
A large-stroke electrostatic micro-actuator
Authors: Towfighian S , Seleim A , Abdel-Rahman E M , Heppler G R
Published: June 2011

Voltage-driven parallel-plate electrostatic actuators suffer from an operation range limit of 30% of the electrostatic gap; this has restrained their application in microelectromechanical systems. In this paper, the travel range of an electrostatic actuator made of a micro-cantilever beam above a fixed electrode is extended quasi-statically to 90% of the capacitor gap by introducing a voltage regulator (controller) circuit designed for low-frequency actuation. The voltage regulator reduces the actuator input voltage, and therefore the electrostatic force, as the beam approaches the fixed electrode so that balance is maintained between the mechanical restoring force and the electrostatic force. The low-frequency actuator also shows evidence of high-order superharmonic resonances that are observed here for the first time in electrostatic actuators.
Derivation and Diagnostic Accuracy of the Surgical Lung Injury Prediction Model
Authors: Kor Daryl J. , Warner David O. , Alsara Anas , Fernández-Pérez Evans R. , Malinchoc Michael , Kashyap Rahul , Li Guangxi , Gajic Ognjen
Published: June 2011

Background

Acute lung injury (ALI) is a serious postoperative complication with limited treatment options. A preoperative risk-prediction model would assist clinicians and scientists interested in ALI. The objective of this investigation was to develop a surgical lung injury prediction (SLIP) model to predict risk of postoperative ALI based on readily available preoperative risk factors.

Methods

Secondary analysis of a prospective cohort investigation including adult patients undergoing high-risk surgery. Preoperative risk factors for postoperative ALI were identified and evaluated for inclusion in the SLIP model. Multivariate logistic regression was used to develop the model. Model performance was assessed with the area under the receiver operating characteristic curve and the Hosmer-Lemeshow goodness-of-fit test.

Results

Out of 4,366 patients, 113 (2.6%) developed early postoperative ALI. Predictors of postoperative ALI in multivariate analysis that were maintained in the final SLIP model included high-risk cardiac, vascular, or thoracic surgery, diabetes mellitus, chronic obstructive pulmonary disease, gastroesophageal reflux disease, and alcohol abuse. The SLIP score distinguished patients who developed early postoperative ALI from those who did not with an area under the receiver operating characteristic curve (95% CI) of 0.82 (0.78-0.86). The model was well calibrated (Hosmer-Lemeshow, P = 0.55). Internal validation using 10-fold cross-validation noted minimal loss of diagnostic accuracy with a mean ± SD area under the receiver operating characteristic curve of 0.79 ± 0.08.

Conclusions

Using readily available preoperative risk factors, we developed the SLIP scoring system to predict risk of early postoperative ALI.
Performance of Anesthetic Depth Indexes in Rabbits under Propofol Anesthesia
Authors: Silva Aura , Campos Sónia , Monteiro Joaquim , Venâncio Carlos , Costa Bertinho , Guedes de Pinho Paula , Antunes Luis
Published: June 2011

Background

The permutation entropy, the approximate entropy, and the index of consciousness are some of the most recently studied electroencephalogram-derived indexes. In this work, a thorough comparison of these indexes was performed using propofol anesthesia in a rabbit model.

Methods

Six rabbits were anesthetized with three propofol infusion rates: 70, 100, and 130 mg · kg⁻¹ · h⁻¹, each maintained for 30 min, in a random order for each animal. Data recording was performed in the awake animals 20, 25, and 30 min after each infusion rate was begun in the recovered animals and consisted of electroencephalogram recordings, evaluation of depth of anesthesia according to a clinical scale, and arterial blood samples for plasma propofol determination. Median and spectral edge frequencies were analyzed for single-scale permutation entropy and composite multiscale permutation entropy, approximate entropy, index of consciousness, and the spectral parameters. The spectral parameters and single-scale and multiscale permutation entropies were corrected for the presence of burst suppression. Performance of the indexes was compared by prediction probability and pharmacodynamic analysis.

Results

The single-scale and composite multiscale permutation entropies with a burst suppression correction showed better prediction probabilities than did the other electroencephalogram-derived parameters but not better than the electromyographic activity.

Conclusion

Single-scale and multiscale permutation entropies may be promising measures of propofol anesthetic depth when corrected for burst suppression. Additional studies should investigate the information measured by electromyography algorithms from commercial monitors of anesthetic depth. The rabbit may be a promising animal model for electroencephalographic studies because it provides a good-quality signal.
Experimental evidence that women's mate preferences are directly influenced by cues of pathogen prevalence and resource scarcity
Authors: Lee Anthony J. , Zietsch Brendan P.
Published: June 2011

When choosing a mate, women are thought to face a trade-off between genetic and parental quality. Recent research suggests that this trade-off is influenced by environmental factors such as pathogen prevalence and resource scarcity, which affect the relative value of genetic and parental quality to offspring fitness. To further investigate these findings, the current study primed 60 women with pathogen prevalence, resource scarcity or an irrelevant threat, before administering a forced trade-off task that assessed mate preferences for traits thought to be indicative of genetic or parental quality. Women primed with pathogen prevalence revealed greater preferences for traits indicative of genetic quality at the expense of traits indicative of parental quality. The reverse was found for women primed with resource scarcity. These findings suggest that environmental factors may directly influence women's mate preferences owing to evolved plasticity, such that mate preferences are flexible in response to environmental factors.
African grey parrots (
Psittacus erithacus
) use inference by exclusion to find hidden food
Authors: Mikolasch Sandra , Kotrschal Kurt , Schloegl Christian
Published: June 2011

Exclusion allows the detection of hidden food when confronted with the choice between an empty and a potentially baited food location. However, exclusion may be based on avoidance of the empty location without drawing inferences about the presence of the food in the baited location. So far, such inferences have been demonstrated in the great apes only: after seeing an experimenter eating one of two food types, which both had been hidden previously in two boxes, the apes were able to choose the box that still contained the other food type. African grey parrots are capable of exclusion, and we here assessed if they are capable of inference by exclusion. In our task, two different but equally preferred food items were hidden in full view of the birds under two opaque cups. Then, an experimenter secretly removed one food type and showed it to the bird. Similarly to the apes, one out of seven parrots significantly preferred the baited cup; control conditions rule out that its choice was based on associative learning or the use of olfactory cues. Thus, we conclude that—like the apes—some grey parrots are able to infer the location of a hidden food reward.
Exploring isospectral spring–mass systems with firefly algorithm
Authors: Dutta Rajdeep , Ganguli Ranjan , Mani V.
Published: June 2011

This paper investigates in-line spring–mass systems (
A

n

), fixed at one end and free at the other, with
n
-degrees of freedom (d.f.). The objective is to find feasible in-line systems (
B

n

) that are isospectral to a given system. The spring–mass systems,
A

n

and
B

n

, are represented by Jacobi matrices. An error function is developed with the help of the Jacobi matrices
A

n

and
B

n

. The problem of finding the isospectral systems is posed as an optimization problem with the aim of minimizing the error function. The approach for creating isospectral systems uses the fact that the trace of two isospectral Jacobi matrices
A

n

and
B

n

should be identical. A modification is made to the diagonal elements of the given Jacobi matrix (
A

n

), to create the isospectral systems. The optimization problem is solved using the firefly algorithm augmented by a local search procedure. Numerical results are obtained and resulting isospectral systems are shown for 4 d.f. and 10 d.f. systems.
The structure and function of cardiac t-tubules in health and disease
Authors: Ibrahim Michael , Gorelik Julia , Yacoub Magdi H. , Terracciano Cesare M.
Published: June 2011

The transverse tubules (t-tubules) are invaginations of the cell membrane rich in several ion channels and other proteins devoted to the critical task of excitation–contraction coupling in cardiac muscle cells (cardiomyocytes). They are thought to promote the synchronous activation of the whole depth of the cell despite the fact that the signal to contract is relayed across the external membrane. However, recent work has shown that t-tubule structure and function are complex and tightly regulated in healthy cardiomyocytes. In this review, we outline the rapidly accumulating knowledge of its novel roles and discuss the emerging evidence of t-tubule dysfunction in cardiac disease, especially heart failure. Controversy surrounds the t-tubules' regulatory elements, and we draw attention to work that is defining these elements from the genetic and the physiological levels. More generally, this field illustrates the challenges in the dissection of the complex relationship between cellular structure and function.
Impact of epistasis and pleiotropy on evolutionary adaptation
Authors: Østman Bjørn , Hintze Arend , Adami Christoph
Published: June 2011

Evolutionary adaptation is often likened to climbing a hill or peak. While this process is simple for fitness landscapes where mutations are independent, the interaction between mutations (epistasis) as well as mutations at loci that affect more than one trait (pleiotropy) are crucial in complex and realistic fitness landscapes. We investigate the impact of epistasis and pleiotropy on adaptive evolution by studying the evolution of a population of asexual haploid organisms (haplotypes) in a model ofNinteracting loci, where each locus interacts withKother loci. We use a quantitative measure of the magnitude of epistatic interactions between substitutions, and find that it is an increasing function ofK. When haplotypes adapt at high mutation rates, more epistatic pairs of substitutions are observed on the line of descent than expected. The highest fitness is attained in landscapes with an intermediate amount of ruggedness that balance the higher fitness potential of interacting genes with their concomitant decreased evolvability. Our findings imply that the synergism between loci that interact epistatically is crucial for evolving genetic modules with high fitness, while too much ruggedness stalls the adaptive process.
Differential dependence of Pavlovian incentive motivation and instrumental incentive learning processes on dopamine signaling
Authors: Wassum Kate M. , Ostlund Sean B. , Balleine Bernard W. , Maidment Nigel T.
Published: June 2011

Here we attempted to clarify the role of dopamine signaling in reward seeking. In Experiment 1, we assessed the effects of the dopamine D1/D2 receptor antagonist flupenthixol (0.5 mg/kg i.p.) on Pavlovian incentive motivation and found that flupenthixol blocked the ability of a conditioned stimulus to enhance both goal approach and instrumental performance (Pavlovian-to-instrumental transfer). In Experiment 2 we assessed the effects of flupenthixol on reward palatability during post-training noncontingent re-exposure to the sucrose reward in either a control 3-h or novel 23-h food-deprived state. Flupenthixol, although effective in blocking the Pavlovian goal approach, was without effect on palatability or the increase in reward palatability induced by the upshift in motivational state. This noncontingent re-exposure provided an opportunity for instrumental incentive learning, the process by which rats encode the value of a reward for use in updating reward-seeking actions. Flupenthixol administered prior to the instrumental incentive learning opportunity did not affect the increase in subsequent off-drug reward-seeking actions induced by that experience. These data suggest that although dopamine signaling is necessary for Pavlovian incentive motivation, it is not necessary for changes in reward experience, or for the instrumental incentive learning process that translates this experience into the incentive value used to drive reward-seeking actions, and provide further evidence that Pavlovian and instrumental incentive learning processes are dissociable.
Genetic effect of single‐nucleotide polymorphisms in the PPARGC1B gene on airway hyperreactivity in asthmatic patients
Authors: Lee S.‐H. , Jang A.‐S. , Woo Park S. , Park J. ‐S. , Kim Y. K. , Uh S.‐T. , Kim Y. H. , Chung I. Y. , Park B.–L. , Shin H. D. , Park C.‐S.
Published: June 2011

Background Peroxisome proliferator‐activated receptor gamma coactivator 1 beta (PPARGC1B) is a co‐activator for intracellular receptors such as the estrogen receptor, PPAR, and glucocorticoid receptor, which are involved in asthma development.

Objectives Genetic association of single‐nucleotide polymorphisms (SNPs) in the PPARGC1B gene with the risk of asthma and airway hyperreactivity (AHR) was investigated, as well as the functional effects of these SNPs on PPARGC1B gene and protein expression.

Methods Direct sequencing of DNA from 24 Korean was performed to identify PPARGC1B SNPs. Genotyping was done in 264 controls and 949 asthmatics using single‐base extension methods. PPARGC1B mRNA levels were measured using real‐time PCR methodology. Luciferase and electrophoretic mobility shift assays (EMSA) were performed to functionally analyse PPARGC1B SNPs on promoter.

Results Eighteen SNPs and one insertion/deletion polymorphism were identified, and seven SNPs were genotyped. No significant difference existed in the distribution of SNPs and haplotypes between the asthmatics and controls. However, the allele frequency of −427C>T and +102525G>A;R265Q showed a significant association with log‐transformed PC20 methacholine values in the asthmatics (P=0.005–0.0004). Real‐time PCR demonstrated higher PPARGC1B mRNA levels in asthmatics having −427CC allele than in those having −427TT or CT alleles (P=0.048). The ratio of the mRNA expression for each PPARGC1B exon4‐mRNA compared with the wild type was similar in peripheral blood mononuclear cells carrying the +102525G>A allele. Luciferase reporter assays revealed that −427C allele caused higher promoter activity than −427T allele. EMSA demonstrated that −427C allele exhibited stronger binding activity to a nuclear protein in 293T cells than did the −427T allele.

Conclusions and Clinical Relevance Polymorphisms of −427C>T on the promoter and those of +102525G>A on exon 5 of the PPARGC1B gene may affect the development of AHR through the modulation of PPARGC1B gene products. The PPARGC1B genotypes may serve as genetic markers for AHR.

Cite this as: S.‐H. Lee, A.‐S. Jang, S. Woo Park, J. ‐S. Park, Y. K. Kim, S.‐T. Uh, Y. H. Kim, I. Y. Chung, B.‐L. Park, H. D. Shin and C.‐S. Park, Clinical & Experimental Allergy, 2011 (41) 1533–1544.