bluuebunny/crossref_metadata_2025 huggingface dataset:
Physical activity and energy balance
Authors: Van Baak Marleen A.
Published: June 2008

Energy expenditure rises above resting energy expenditure when physical activity is performed. The activity-induced energy expenditure varies with the muscle mass involved and the intensity at which the activity is performed: it ranges between 2 and 18 METs approximately. Differences in duration, frequency and intensity of physical activities may create considerable variations in total energy expenditure. The Physical Activity Level (= total energy expenditure divided by resting energy expenditure) varies between 1.2 and 2.2–2.5 in healthy adults. Increases in activity-induced energy expenditure have been shown to result in increases in total energy expenditure, which are usually greater than the increase in activity-induced energy expenditure itself. No evidence for increased spontaneous physical activity, measured by diary, interview or accelerometer, was found. However, this does not exclude increased physical activity that can not be measured by these methods. Part of the difference may also be explained by the post-exercise elevation of metabolic rate.

If changes in the level of physical activity affect energy balance, this should result in changes in body mass or body composition. Modest decreases of body mass and fat mass are found in response to increases in physical activity, induced by exercise training, which are usually smaller than predicted from the increase in energy expenditure. This indicates that the training-induced increase in total energy expenditure is at least partly compensated for by an increase in energy intake. There is some evidence that the coupling between energy expenditure and energy intake is less at low levels of physical activity. Increasing the level of physical activity for weight loss may therefore be most effective in the most sedentary individuals.
Macronutrient balances and obesity: the role of diet and physical activity
Authors: Astrup Arne
Published: June 2008

Observational cross-sectional and longitudinal studies suggest that a high fat diet and physical inactivity are independent risk factors for weight gain and obesity. Mechanistic and intervention studies support that fat possesses a lower satiating power than carbohydrate and protein, and a diet low in fat therefore decreases energy intake. The effect of dietary fat on energy balance is enhanced in susceptible subjects, particularly in sedentary individuals with a genetic predisposition to obesity who consume a high fat diet.

Dietary carbohydrate promotes its own oxidation by an insulin-mediated stimulation of glucose oxidation. In contrast, high fat meals do not increase fat oxidation acutely. A sedentary life-style and low physical fitness cause a low muscular fat oxidation capacity, and the consumption of a high fat diet by these individuals promotes fat storage in a synergistic fashion.

Ad libitum low fat diets cause weight loss proportional to pre-treatment body weight in a dose-dependent way, i.e. weight loss is correlated positively to the reduction in dietary fat content. Increased physical activity prevents relapse after weight loss and studies have shown that those who keep up a higher level of physical activity are more successful in maintaining the reduced body weight. In conclusion, important interactions exist between genetic make up, dietary fat and physical fitness, so that a low fitness level and susceptible genes reduce muscular fat oxidation capacity which may decrease the tolerance of dietary fat. Increasing daily physical activity and reducing dietary fat content may be more effective when combined than when separate in preventing weight gain and obesity.
Interaction between physical activity and diet: implications for blood pressure management in primary care
Authors: Margetts BM , Little P , Warm D
Published: June 2008

Objectives:

This review summarises the evidence for the effectiveness of primary care based interventions of diet and physical activity aimed at reducing blood pressure.

Background:

As blood pressure rises so does the risk of heart disease and stroke. There is a large literature on the effects on blood pressure of changing various aspects of diet either as single nutrient interventions, patterns of food consumption, or the addition of dietary supplements (potassium, magnesium, and fish oil). Controlled trials have been undertaken to assess the relative benefits of lifestyle changes in activity (walking etc) compared with more structured exercise programmes. There is sufficient evidence to suggest that changes in diet and activity under controlled conditions can reduce blood pressure and delay or reduce the need for drug treatment in subjects who are hypertensive. What is less clear is how to achieve these lifestyle changes in the primary care setting as part of routine clinical management.

Results:

There have been a number of systematic reviews undertaken to evaluate the evidence. The interventions were either delivered alone or in combination with other advice, either with or without aids, and by various practice nurse staff (GP, nurse, Dietitian); follow-up varied from 3 months to a year. Compliance with the advice was generally not measured. The variability in the quality of the studies and interventions made it difficult to draw conclusions: any effects seen tended to be small.

Conclusions:

Equivocal results (non statistically significant reductions) should not be considered as proof of no effect without careful consideration of the effects of chance, bias and confounding, and without better measures of compliance. There is little debate that, under investigator control, blood pressure can be reduced by changes in diet and activity. Changes to a ‘healthy’ diet (low in total and saturated fat; energy intake balanced with expenditure to maintain or achieve optimal body weight; low in salt; high in fruits, vegetables, legumes; and whole grains) and increases in modest levels of physical activity (walking etc) would be expected to reduce blood pressure by between two and four mmHg. A shift in the population distribution of this order would be expected to have a substantial impact on population mortality patterns and could be achieved cost-effectively in primary care.
Interaction of physical activity and diet: implications for haemostatic factors
Authors: Rauramaa Rainer , Väisänen SB
Published: June 2008

Regular moderate intensity physical activity and habitual diet providing no more than one third of energy from fats have been recommended for the prevention of atherosclerotic diseases. The background for these guidelines is the key role of plasma lipids. However, the importance of thrombogenesis in acute myocardial infarction has become obvious during the last decade. Hyperlipidaemia and excess of adipose tissue increase platelet aggregability and blood coagulation, and decrease fibrinolysis. Both regular physical activity and dietary fat reduction decrease blood lipids and body fat thereby diminishing the risk of thrombosis. Currently, data on interactions between physical activity and diet on haemostasis are scarce, and the few studies available have not demonstrated additional effects when these two lifestyle modifications have been combined. This paper is restricted only to studies using controlled randomized design. Regular moderate intensity physical activity as well as diet rich in omega-3 fatty acids decrease platelet aggregability. The effects of regular physical activity on plasma fibrinogen remain contradictory, while the impact of diet is even less clear. Plasminogen activator inhibitor-1, a possible link between insulin resistance syndrome and coronary heart disease, may decrease due to physical training or low fat diet. It can be hypothesized that moderation in physical activity and diet carries a more powerful impact on blood coagulation and fibrinolysis than either lifestyle modification alone. Studies focusing on the interactions of regular moderate physical activity and fat-modified diet are needed in efforts to optimize the preventive actions by lifestyle changes.
Longitudinal relationships between lifestyle and cardiovascular and bone health status indicators in males and females between 13 and 27 years of age; a review of findings from the Amsterdam Growth and Health Longitudinal Study
Authors: Van Mechelen W. , Twisk J.W.R , Kemper H.C.G , Snel J. , Post G.B.
Published: June 2008

The Amsterdam Growth and Health Longitudinal Study is longitudinal co-hort study on 181 males and females initially aged 13 years, with follow-up measurements at ages 14, 15, 16, 21 and 27 years.

Methods:

Anthropometrical, biological and lifestyle parameters, and age 27 also bone mineral density (BMD) of the lumbar spine (L2–L4), were measured repeatedly. Adolescent dietary intake and physical activity was related to adult cardiovascular and bone health status indicators by MLR; longitudinal relationships between physical activity and dietary intake, and cardiovascular health status indicators were assessed by GEE-analysis.

Results:

Adolescent physical activity was not related to most of the indicators of adult cardiovascular health status, with the exception of a positive relationship with the waist-to-hip in females; in males ‘energetic’ adolescent physical activity contributed significantly to adult BMD; both in males and females, when taking the entire longitudinal period into account, peak strain physical activity was a relatively more important predictor of adult BMD than ‘energetic’ physical activity; calcium intake during adolescence was not a significant predictor of bone health status measured at age 27, both in males and females; a consistent significant positive longitudinal relationship was found between physical activity and serum HDL-cholesterol and significant negative longitudinal relationships were found with the subscapular skinfold and with body fat mass; a positive longitudinal relationship was found between serum total cholesterol (TC) and cholesterol intake, saturated fat (SFA) intake and the Keys-score; a negative longitudinal relationship was found between TC and polyunsaturated fat and total energy intake; for HDL a positive longitudinal relationship was found with SFA intake; low tracking was found for physical (in-) activity and dietary intake variables.
Health potential of soy isoflavones for menopausal women
Authors: Anderson John JB , Anthony Mary S , Cline J Mark , Washburn Scott A , Garner Sanford C
Published: June 2008

Objective:

To review the current literature on the effects of soy isoflavones, one class of phyto-oestrogens, on cardiovascular diseases, osteoporosis, cancer and climacteric symptoms.

Design:

Many study designs were employed in the reports reviewed here, including prospective human trials, observational human studies, animal experiments andin vitrocell studies that explored the protective or preventive effects of soy isoflavones (genistein, daidzein and glycitein alone or mixed).

Setting:

Diverse settings were employed, depending on study design.

Subjects:

Human subjects, mostly menopausal or postmenopausal, were included, as were animal models and specific cell types.

Results:

The findings were: (i) isoflavones plus soy protein together were needed to obtain the highly significant beneficial results on blood lipids and arterial dimensions; (ii) isoflavone treatments alone at high doses (relative to above) consistently improved bone parameters in rodent ovariectomized models, but not in humans or primates; (iii) isoflavones were not consistent in exerting positive effects regarding the prevention or treatment of cancers of the mammary glands, uterus and colon; and (iv) the effects of isoflavones on climacteric symptoms were not clear-cut.

Conclusions:

The promise of soy isoflavones reducing chronic disease risk seems to be non-uniform, with the most conclusive benefits occurring in the prevention of cardiovascular diseases, but other organ systems, such as skeletal and reproductive tissues, may also benefit from the consumption of soy and soy-derived products.
Iron intake and iron status of preschool children: associations with breakfast cereals, vitamin C and meat
Authors: Gibso Sigrid A
Published: June 2008

Objective:

To examine associations between breakfast cereal consumption and iron status and identify dietary patterns that might improve iron status in this vulnerable group.

Design:

Analysis of data from the UK National Diet and Nutrition Survey (NDNS) of children aged 1.5–4.5 years, including dietary intakes calculated from 4-day weighed records.

Subjects:

Data were used from 904 children with haematological measurements, excluding those taking iron supplements; 20% had low iron stores (ferritin < 10 μg l−1) while 8% were anaemic (Hb < 11 g dl−1).

Results:

High cereal consumers had significantly higher iron intakes than low cereal consumers (classified by tertiles) but the 10% difference in mean ferritin levels was not significant (P = 0.067). Lower intakes of vitamin C and meat among high consumers of cereal may have diluted the impact of cereal iron on iron status. When children were reclassified according to their intakes of vitamin C and iron from meat and breakfast cereals, the group with high (above median) intakes of two or more factors had a higher mean haemoglobin (Hb) level and a lower prevalence of anaemia compared with the group with low (below median) intakes of all three dietary constituents.

Conclusions:

Nutritional advice that aims to improve iron status should emphasize not only rich sources of iron but also factors that may enhance or inhibit absorption. Strategies to optimize iron status in this vulnerable age group include consuming an iron-fortified breakfast cereal, vitamin C-rich fruit or drink at breakfast, and avoiding tea with (or after) meals.
Food and nutrient intake of a national sample of 4-year-old children in 1950: comparison with the 1990s
Authors: Prynne CJ , Paul AA , Price GM , Day KC , Hilder WS , Wadsworth MEJ
Published: June 2008

Objective:

To evaluate the food and nutrient intake of members of a birth cohort study when young children in 1950 and investigate differences from present-day children's diets.

Design:

One-day recall diet records from the MRC National Survey of Health and Development (NSHD) (1946 Birth Cohort) at age 4 years were analysed for energy and selected nutrients and compared to the published results for 4-year-olds in the 1992/93 National Diet and Nutrition Survey (NDNS).

Setting:

England, Scotland and Wales in 1950 and 1992/93.

Subjects:

4599 children in 1950 and 493 children in 1992/93.

Results:

Mean (SD) daily intakes in 1950 were energy 1445 (343) kcal, or 6.1 (1.4) MJ, protein 46 (11)g, fat 64 (20)g, starch 117 (33)g, sugar 62 (24)g, unavailable carbohydrate 13 (4)g, calcium 736 (230)mg, iron 7.7 (2.1)mg, retinol 738 (1273) μg, carotene 1049 (1130) μg and vitamin C 40 (26) mg. Compared to 1992/93, the 1950 diet contained substantially more bread and vegetables and less sugar and soft drinks, giving it a higher starch and fibre content and making it more in line with current recommendations on healthy eating. However, fat provided 40% of energy in 1950, compared to 35% in 1992/93. In 1950, red meat was an important source of iron, but by 1992 most iron came from fortified breakfast cereals. Vitamin C came mainly from vegetables in 1950, but from soft drinks in 1992.

Conclusions:

The relative austerity of post-war food supplies resulted in food and nutrient intakes in 1950 which in many respects may well have been beneficial to the health of young children, despite fat intake being higher than present-day recommendations.
Assessing the diet of adolescent girls in the UK
Authors: Robinson Siân , Skelton Ria , Barker Mary , Wilman Clare
Published: June 2008

Objective:

To assess the ability of a food frequency questionnaire (FFQ1) and a food checklist (FCL) to determine energy and macronutrient intakes of adolescent girls in the general population.

Design:

Energy and macronutrient intakes determined by FFQ1 and the FCL were compared with those from a 7-day weighed dietary record (WDR). The reproducibility of FFQ1 was assessed by a comparison of intakes with those from a repeated questionnaire (FFQ2) completed a month later.

Setting:

Southampton, UK.

Subjects:

Forty-seven 15-year-old girls completed FFQ1 and the WDR and FCL; and 61 girls completed FFQ1 and FFQ2.

Results:

The broad dietary patterns described by the three methods of assessment were similar, although absolute intakes differed. Energy and macronutrient intakes determined by FFQ1 were higher than those recorded in the WDR (allP< 0.001), but intakes assessed by the FCL and WDR were similar. Only FFQ1-assessed energy intakes appeared consistent with predicted energy requirements. With the exception of protein intake, there was reasonable agreement between FFQ1 and the WDR in their estimation of energy and macronutrient intake (range of correlation coefficients 0.28 for energy to 0.33 for carbohydrate). The poorer agreement between FFQ1 and the WDR in their estimates of protein intake arose principally from the misclassification of meat and fish intake, although there was no obvious explanation for this. Energy and macronutrient intakes were similar for FFQ1 and FFQ2.

Conclusions:

Adolescent girls give reproducible answers in response to a self-administered FFQ, which yield useful information about their broad dietary patterns. The FFQ may be a more suitable dietary assessment method than prospective records for use in general population studies of girls of this age. We discuss suggestions for its improved performance.
Women Asylum Seekers and Refugees: Opportunities, Constraints and the Role of Agency
Authors: Hunt Lisa
Published: June 2008

This article is based on the findings of research undertaken towards a doctoral thesis funded by the University of Leeds. The research focuses upon the actions and experiences of women asylum seekers and refugees living in West Yorkshire. While acknowledging that the context in which women find themselves can present a number of barriers, this paper looks at their actions and practices at the individual and collective levels. It illustrates that some women are able to draw on the resources available, and are engaged in activities that not only assist their own settlement in the host society but also assist the development of support structures for future arrivals of asylum seekers and refugees.
Ethnicity, Policy and Teenage Parenthood in England: Findings from a Qualitative Study
Authors: Owen Jenny , Higginbottom Gina M A , Kirkham Mavis , Mathers Nigel , Marsh Peter
Published: June 2008

Ethnicity and racialised identity have been salient themes in USA research and policy on teenage parenthood, in contrast with the UK context. This article presents findings from interviews with professionals in support services for young parents, with three main conclusions. Firstly, appropriate data collection systems are not in place to establish whether minority young parents face specific barriers in accessing services. Secondly, professionals’ accounts converge with young parents’ accounts, emphasising age rather than ethnicity as shaping patterns of identification and stigmatisation. Lastly, professional ‘ecologies of practice’ exist in some tension with the homogenising emphasis of UK national policy discourses.
Integrated Services in Activation Policies in Finland and Italy: A Critical Appraisal
Authors: Genova Angela
Published: June 2008

The integration of welfare services in activation policies has been one of the common answers to welfare challenges in EU member states over the last two decades. The process has been interwoven with the rescaling both downwards and upwards of welfare regulative authorities. The article discusses the role of integrated services in activation policies in relation to the centralisation and decentralisation of welfare policies in a comparative perspective of different EU welfare regimes and highlights the role of local institutional milieus in shaping path-dependent modes of governance in integrated services.
Biot‐type scattering effects in gas hydrate‐bearing sediments
Authors: Rubino J. Germán , Ravazzoli Claudia L. , Santos Juan E.
Published: June 2008

This paper studies the energy conversions that take place at discontinuities within gas hydrate‐bearing sediments and their influence on the attenuation of waves traveling through these media. The analysis is based on a theory recently developed by some of the authors, to describe wave propagation in multiphasic porous media composed of two solids saturated by a single‐phase fluid. Real data from the Mallik 5L‐38 Gas Hydrate Research well are used to calibrate the physical model, allowing to obtain information about the characteristics of the cementation between the mineral grains and gas hydrates for this well. Numerical experiments show that, besides energy conversions to reflected and transmitted classical waves, significant fractions of the energy of propagating waves may be converted into slow‐waves energy at plane heterogeneities within hydrated sediments. Moreover, numerical simulations of wave propagation show that very high levels of attenuation can take place in the presence of heterogeneous media composed of zones with low and high gas hydrate saturations with sizes smaller or on the order of the wavelengths of the fast waves at sonic frequencies. These attenuation levels are in very good agreement with those measured at the Mallik 5L‐38 Gas Hydrate Research Well, suggesting that these scattering‐type effects may be a key‐parameter to understand the high sonic attenuation observed at gas hydrate‐bearing sediments.
Excitation of ducted gravity waves in the lower thermosphere by tropospheric sources
Authors: Snively Jonathan B. , Pasko Victor P.
Published: June 2008

Short‐period, small‐scale gravity waves are frequently observed in nighttime airglow imaging experiments. These waves are often found to be ducted and may be confined to a thin region of altitude in the mesosphere or lower thermosphere. An apparent paradox of high‐altitude ducted waves is the nature of the source; it is necessary that a ducted wave be excited in situ or have been able to tunnel into the duct from another atmospheric region. In this paper, analytical and numerical solutions are presented for simple thermally ducted gravity waves that are Doppler‐shifted by constant background winds. Using a continuous analytical model, duct dispersion properties are calculated for three case studies. Using a fully nonlinear numerical model, several scenarios are explored by which a tropospheric source can excite these thermally ducted wave modes. First, we validate the analytical and numerical models for the classical case of linear wave tunneling. Second, we examine the nonlinear excitation of ducted waves due to resonant wave self‐interactions associated with realistic propagation and small‐scale wavebreaking, for propagation in the same direction as the wind flow. Third, we consider the case of ducted wave excitation and propagation opposite to the direction to wind flow. Specifically, where horizontal group and phase velocities exhibit opposite sign in the ground‐relative frame. The results suggest that ducted waves of very short period can be excited in the lower thermosphere by tropospheric sources, via simple linear and nonlinear processes. These excitation mechanisms are likely to be robust for a range of realistic thermal and thermal‐Doppler ducts.
Particle precipitation during ICME‐driven and CIR‐driven geomagnetic storms
Authors: Longden N. , Denton M. H. , Honary F.
Published: June 2008

Interplanetary coronal mass ejections (ICME) and corotating interaction regions (CIR) alter the parameters of the solar wind and interplanetary magnetic field (IMF) that affect conditions in the Earth's magnetosphere and particle precipitation in the auroral zone. We perform a superposed epoch study of the effects of ICME‐dominated and CIR‐dominated solar wind on particle precipitation during geomagnetic storms. We use data from a set of 38 CIR events and 33 ICME events. Particle precipitation is inferred from cosmic noise absorption (CNA) recorded by the riometer at Abisko. The electron flux intensity at geosynchronous orbit close to the location of the riometer is taken from the synchronous orbit particle analyzer (SOPA) onboard the Los Alamos National Laboratory (LANL) satellite LANL‐01A. The results show that mean CNA is more intense during the main phase of ICME‐driven storms. In contrast, mean CNA remains elevated for a much longer period during CIR‐driven storms indicating prolonged periods of particle precipitation. Enhanced CNA over a sustained period of time is observed during CIR‐driven storms that are categorized as only weak or moderate in terms of the response that they drive in the Dst index (Dst >−100 nT). This result indicates that events which may be considered geomagnetically ineffective have a significant effect on particle precipitation in the auroral zone. The elevated CNA observed during CIR‐driven storms is accompanied by elevated electron flux intensity, measured at geosynchronous orbit, over all channels in the 50–500 keV range at all local times.
Collapse and reconstruction of Monowai submarine volcano, Kermadec arc, 1998–2004
Authors: Wright Ian C. , Chadwick William W. , de Ronde Cornel E. J. , Reymond Dominique , Hyvernaud Olivier , Gennerich Hans‐Hermann , Stoffers Peter , Mackay Kevin , Dunkin Miles A. , Bannister Stephen C.
Published: June 2008

Monowai submarine volcano is one of the three most historically active volcanoes of the Kermadec arc. Repeat multibeam surveys of Monowai Cone from September 1998 and September 2004 and T wave data recorded by the Réseau Sismique Polynésien network for the same period document the collapse and subsequent regrowth of the cone within this 6‐a period. Grid differencing of the two bathymetric data sets, acquired 6 a apart, reveals that a landslide ∼2230 m long occurred between the surveys, within which a postcollapse cone and talus ridge (∼0.023 km3 in volume) subsequently formed. The volume of this collapse, minus postcollapse construction, is ∼0.085 km3. We interpret an unusual, strong‐amplitude T wave event on 24 May 2002 as recording “hot landsliding”, where the 100‐ to 160‐m‐thick collapse has “unroofed” the uppermost parts of the vent conduit, with the subsequent explosive interaction, and cooling, of hot magma and volcaniclastic rubble with ambient seawater. This interpretation is consistent with the lack of emergent events, sharp onset, and large amplitude of the 24 May 2002 T waves. The subsequent >2500 T wave events, between November 2002 and September 2004, occurred in swarms with emerging and waning activity and with typical explosive volcanic acoustic signatures, which are interpreted as recording the regrowth of an ∼90‐m‐high cone back to a near‐1998 elevation, at an average rate of 47 m a−1. This study provides (1) a lower bound for frequency‐magnitude relationships of landsliding for submarine arc volcanoes and (2) estimates of 0.013 km3 a−1 of submarine cone growth during eruptive cycles.
Simulation study of the two‐dimensional Burridge‐Knopoff model of earthquakes
Authors: Mori Takahiro , Kawamura Hikaru
Published: June 2008

Spatiotemporal correlations of the two‐dimensional spring‐block (Burridge‐Knopoff) model of earthquakes are extensively studied by means of numerical computer simulations. The model is found to exhibit either a “subcritical”, “supercritical” or “near‐critical” behavior, depending on the values of the model parameters. Transition between the “subcritical” and “supercritical” regimes is either continuous or discontinuous. Seismic events in the “subcritical” regime and those in the “supercritical” regime at larger magnitudes exhibit universal scaling properties. In the “supercritical” regime, eminent spatiotemporal correlations, e.g., a remarkable growth of seismic activity preceding the main shock, arise in earthquake occurrence, whereas such spatiotemporal correlations are significantly suppressed in the “subcritical” regime. Seismic activity is generically suppressed just before the main shock in a close vicinity of the epicenter of the upcoming event while it remains to be active in the surroundings (the Mogi doughnut). It is also observed that, before and after the main shock, an apparent B‐value of the magnitude distribution decreases or increases in the “supercritical” or “subcritical” regimes, respectively. Such distinct precursory phenomena may open a way to the prediction of the upcoming large event.
Pacific absolute plate motion since 145 Ma: An assessment of the fixed hot spot hypothesis
Authors: Wessel Paul , Kroenke Loren W.
Published: June 2008

Using the geometry and ages from 12 Pacific seamount chains, we have determined two new absolute plate motion models that now extend our self‐consistent and high‐resolution models with covariance estimates back to 145 Ma. The WK08‐A model maps the full uncertainty in the age progressions into uncertainties in rotation opening angles, yielding a relatively smooth plate motion model. The WK08‐G model relaxes the mapping of age uncertainties in order to better isolate secondary geometry changes seen along many coregistered chains. Both models have been used to assess the viability of the fixed hot spot hypothesis in the Pacific. In determining the models, we found that only a small group of age samples had to be discarded on the grounds that they were discordant with the dominant trends. We were able to connect plate motions for pre‐ and post‐Emperor age intervals by including the Ratak‐Gilbert‐Ellice and Musicians trails in our analysis. However, as no active hot spot locations exist for the older chains, their inclusion adds additional model parameters. Both age and geometry misfits increase with age, reflecting the observed increase in age uncertainties and the general widening of trails. Secondary (and short‐lived) changes in absolute plate motion mapped in WK08‐G appear to correlate with the timing and sense of motion of known Pacific Rim tectonic events. Analysis of interchain distances between coeval samples from the Hawaii and Louisville chains suggests possible discrepancies during the older Emperor stage that are compatible with predictions of hot spot drift. We computed a new apparent polar wander path for the Pacific and found a high degree of correspondence with paleomagnetically derived paths, as long as solutions allowing for anomalous skewness were included in the latter. Our polar wander path suggests that there might have been some true polar wander during the Emperor stage, complemented by a smaller amount of hot spot drift than otherwise required. We show that chain geometries and ages, combined with future paleolatitude determinations from additional sites and chains could enable an observation‐based description of both hot spot and plate motions without relying on predictions of hot spot drift derived from mantle flow calculations.
Beryllium‐10 and beryllium‐7 in precipitation in Dübendorf (440 m) and at Jungfraujoch (3580 m), Switzerland (1998–2005)
Authors: Heikkilä U. , Beer J. , Alfimov V.
Published: June 2008

Beryllium‐10 and beryllium‐7 have been measured in monthly precipitation samples at a high (Jungfraujoch, 46.32°N 7.59°E, 3580 m) and a low (Dübendorf, 47.25°N 8.27°E, 440 m) altitude station in Switzerland from 1998 till today. The average deposition fluxes of 7Be are 380 ± 30 atoms m−2 s−1 in Dübendorf and 320 ± 20 atoms m−2 s−1 at Jungfraujoch, and the fluxes of 10Be are 810 ± 70 atoms m−2 s−1 in Dübendorf and 810 ± 60 atoms m−2 s−1 at Jungfraujoch. The 10Be/7Be ratio measured at Jungfraujoch (2.4 ± 0.1) is higher than in Dübendorf (2.1 ± 0.1), which is probably caused by a greater share of stratospheric air at Jungfraujoch in which the 7Be content is reduced because of radioactive decay. The ratios correspond to a mean atmospheric residence time of ∼110–120 d. The deposition fluxes show a seasonal change with a summer maximum and a winter minimum. The 10Be/7Be ratio exhibits a maximum in the first half of the year at Jungfraujoch in accordance with seasonal stratosphere‐troposphere exchange (STE) variations. In Dübendorf the maximum occurs 1 month later. An analysis with a two‐box model shows that the calculated variability due to seasonally varying STE explains only one third of the observed variability in the 10Be/7Be ratio. The rest of the variability is caused by local effects, such as the precipitation rate and the larger than average STE variability at the midlatitudes. According to the model calculations, the global mean 10Be/7Be ratio only varies between 1.1 and 1.5 with a seasonally varying STE. The larger measured values in the midlatitudes point to a latitudinal dependence of the 10Be/7Be ratio.
Observational evidence on the stability of the hydro‐glaciological regime of subglacial Lake Vostok
Authors: Richter A. , Popov S. V. , Dietrich R. , Lukin V. V. , Fritsche M. , Lipenkov V. Y. , Matveev A. Y. , Wendt J. , Yuskevich A. V. , Masolov V. N.
Published: June 2008

Combined geodetic, geophysical and glaciological in situ measurements are interpreted regarding surface height changes over subglacial Lake Vostok and the local mass balance of the ice sheet at Vostok station. Repeated GPS observations spanning 5 years and long‐term surface accumulation data show that the height of the lake surface has not changed over the observation period. The application of the mass conservation equation to purely observational data yields an ice mass balance for Vostok station close to equilibrium.
Towards universal potentials for (H2)2 and isotopic variants: Post-Born–Oppenheimer contributions
Authors: Diniz Leonardo G. , Mohallem José R.
Published: June 2008

Adiabatic corrections are evaluated for the interaction of two hydrogen molecules (H2)2 and isotopic variants. Their contribution to the cluster formation amount up to 10% of the interaction energy. Added to the best ab initio Born–Oppenheimer isotropic potential, they correct especially its short range repulsive part. Calculations of second virial coefficients are improved in general, with an impressive agreement with experiments for gaseous D2 in a large range of temperatures. The potentials are available in both analytical and numerical forms.
The evolution of intermediate-range order in molten network-forming materials
Authors: Wilson Mark , Sharma Bevan K.
Published: June 2008

The atomistic origin of the intermediate-range order (IRO) is investigated for an archetypal network-forming liquid. A pairwise additive potential model is chosen which is augmented with a description of the (many-body) anion polarization. The anion polarizability and system temperature are both systematically varied in order to control the network topology. The change in the IRO is monitored via the construction of Bhatia–Thornton structure factors which highlight the effect of chemical composition and network topology. The atomistic origin of the first-sharp diffraction peak in the concentration-concentration function, SCC(k), is discussed in terms of the connectivity of the polyhedral network. The atomistic origin of the IRO is discussed by reference to previous analyses.
Growth pattern and electronic properties of acetonitrile clusters: A density functional study
Authors: Nigam Sandeep , Majumder Chiranjib
Published: June 2008

We report a systematic theoretical study on the growth pattern and electronic properties of acetonitrile clusters [(CH3CN)n (n=1,9,12)] using density functional approach at the B3LYP∕6-31++G(d,p) level. Although we have considered a large number of configurations for each cluster, the stability of the lowest energy isomer was verified from the Hessian calculation. It is found that the lowest energy isomer of the dimer adopts an antiparallel configuration. For trimer and tetramer, cyclic ring structures were found to be favored over the dipole stabilized structure. In general, it is found that the intermolecular CH⋯N interactions play a significant role in the stabilization of the cyclic layered geometry of acetonitrile clusters. A critical comparison between trimer and tetramer clusters suggests that the three member cyclic ring is more stable than four member rings. The growth motif for larger clusters (n=5–9,12) follows a layered pattern consisting of three or four membered rings, which, in fact, is used as the building block. Based on the stability analysis, it is found that clusters with an even number of molecular entities are more stable than the odd clusters, except trimer and nonamer. The exceptional stability of these two clusters is attributed to the formation of trimembered cyclic rings, which have been found to form the building blocks for larger clusters.
Development and fluidic simulation of microneedles for painless pathological interfacing with living systems
Authors: Chakraborty Suman , Tsuchiya Kazuyoshi
Published: June 2008

In this paper, we investigate the development and fluidic analysis of microneedles integrated with painless blood extraction systems that aim to mimic the female mosquito’s blood sampling techniques in certain respects. The microneedles are fabricated by employing the sputtering deposition method. A fluid mechanical analysis is presented toward predicting the transport mechanisms inside the microneedle as dynamically evolving consequences of the resistive forces and the aiding surface tension influences. The theoretical predictions are comprehensively compared to experimental data, and excellent agreements are found for all cases.
Stretched-exponential photoionization of the metastable defects in gallium doped Cd0.99Mn0.01Te: Statistical origins of the short-time power-law in response data
Authors: Trzmiel J. , Weron K. , Placzek-Popko E.
Published: June 2008

The subject of the present study is the low temperature nonexponential transients of photoconductivity build-up in gallium doped Cd0.99Mn0.01Te semiconducting mixed crystals possessing metastable defects, so called DX centers. The phototransients were analyzed in terms of two approaches. The first one was the two-exponential fitting that is usually applied to explain the persistent photoeffect build-up in materials with DX centers. The second, implemented in the above-mentioned semiconductors, was the stochastic model of relaxation leading to the stretched-exponential result. The latter fitting was found to be more appropriate for it justifies the short-time power-law exhibited by the phototransient response. According to the stochastic approach this behavior results from a heavy-tailed distribution of photoionized DX centers. The distribution can have its origin in different local arrangements.
Continuous current and surface potential models for undoped and lightly doped double-gate metal-oxide-semiconductor field-effect transistors
Authors: Abd Elhamid Hamdy , Deen M. J.
Published: June 2008

We have introduced a continuous, explicit, surface potential model for symmetric undoped and lightly doped double gate metal-oxide-semiconductor field-effect transistor devices. The surface potential model considered both hole and electron quasi-Fermi potential effects. An explicit current model has been introduced in terms of both source and drain charge densities at which hole and electron quasi-Fermi level or IMREFs are defined. The introduced models are directly related to the device biasing and device structure without the need for fitting parameters. Both of the surface potential and current models are continuous from below to above threshold and from linear to saturation of operation regimes. Good agreement has been obtained when our analytical models are compared to numerical results. The effects of hole IMREF on the small-signal (or ac) parameters are also reported. We predicted that the presence of holes has raised the saturation voltage. Also, we have observed from the gate capacitance curve that the hole IMREF should be taken into our account for low frequency applications.
Heterodyne detector for measuring the characteristic of elliptically polarized microwaves
Authors: Leipold Frank , Nielsen Stefan , Michelsen Susanne
Published: June 2008

In the present paper, a device is introduced, which is capable of determining the three characteristic parameters of elliptically polarized light (ellipticity, angle of ellipticity, and direction of rotation) for microwave radiation at a frequency of 110GHz. The device consists of two perpendicular orientated pickup waveguides. A heterodyne technique mixes the microwave frequency down to frequencies on the order of 200MHz. An oscilloscope is used to determine the relative amplitudes of the electrical fields and the phase shift in between, from which the three characteristic parameters can be calculated. Results from measured and calculated wave characteristics of an elliptically polarized 110GHz microwave beam for plasma heating launched into the TEXTOR-tokamak experiment are presented. Measurement and calculation are in good agreement.
ATP is released by monocytes stimulated with pathogen-sensing receptor ligands and induces IL-1β and IL-18 secretion in an autocrine way
Authors: Piccini Alessandra , Carta Sonia , Tassi Sara , Lasiglié Denise , Fossati Gianluca , Rubartelli Anna
Published: June 2008

IL-1β and IL-18 are crucial mediators of inflammation, and a defective control of their release may cause serious diseases. Yet, the mechanisms regulating IL-1β and IL-18 secretion are partially undefined. Both cytokines are produced as inactive cytoplasmic precursors. Processing to the active form is mediated by caspase-1, which is in turn activated by the multiprotein complex inflammasome. Here, we show that in primary human monocytes microbial components acting on different pathogen-sensing receptors and the danger-associated molecule uric acid are all competent to induce maturation and secretion of IL-1β and IL-18 through a process that involves as a first event the extracellular release of endogenous ATP. ATP release is followed by autocrine stimulation of the purinergic receptors P2X
7
. Indeed, antagonists of the P2X
7
receptor (P2X
7
R), or treatment with apyrase, prevent IL-1β and IL-18 maturation and secretion triggered by the different stimuli. At variance, blocking P2X
7
R activity has no effects on IL-1β secretion by monocytes carrying a mutated inflammasome that does not require exogenous ATP for activation. P2X
7
R engagement is followed by K
+
efflux and activation of phospholipase A
2
. Both events are required for processing and secretion induced by all of the stimuli. Thus, stimuli acting on different pathogen-sensing receptors converge on a common pathway where ATP externalization is the first step in the cascade of events leading to inflammasome activation and IL-1β and IL-18 secretion.
Delayed antiviral plus immunomodulator treatment still reduces mortality in mice infected by high inoculum of influenza A/H5N1 virus
Authors: Zheng Bo-Jian , Chan Kwok-Wah , Lin Yong-Ping , Zhao Guang-Yu , Chan Chris , Zhang Hao-Jie , Chen Hong-Lin , Wong Samson S. Y. , Lau Susanna K. P. , Woo Patrick C. Y. , Chan Kwok-Hung , Jin Dong-Yan , Yuen Kwok-Yung
Published: June 2008

The mortality of human infection by influenza A/H5N1 virus can exceed 80%. The high mortality and its poor response to the neuraminidase inhibitor oseltamivir have been attributed to uncontrolled virus-induced cytokine storm. We challenged BALB/c mice with 1,000 LD50of influenza A/Vietnam/1194/04. Survival, body weight, histopathology, inflammatory markers, viral loads, T lymphocyte counts, and neutralizing antibody response were documented in infected mice treated individually or in combination with zanamvir, celecoxib, gemfibrozil, and mesalazine. To imitate the real-life scenario, treatment was initiated at 48 h after viral challenge. There were significant improvements in survival rate (P= 0.02), survival time (P< 0.02), and inflammatory markers (P< 0.01) in the group treated with a triple combination of zanamivir, celecoxib, and mesalazine when compared with zanamivir alone. Zanamivir with or without immunomodulators reduced viral load to a similar extent. Insignificant prolongation of survival was observed when individual agents were used alone. Significantly higher levels of CD4+and CD8+T lymphocytes and less pulmonary inflammation were also found in the group receiving triple therapy. Zanamivir alone reduced viral load but not inflammation and mortality. The survival benefits of adding celecoxib and mesalazine to zanamivir could be caused by their synergistic effects in reducing cytokine dysfunction and preventing apoptosis. Combinations of a neuraminidase inhibitor with these immunomodulators should be considered in randomized controlled treatment trials of patients suffering from H5N1 infection.
Neural substrates underlying human delay and trace eyeblink conditioning
Authors: Cheng Dominic T. , Disterhoft John F. , Power John M. , Ellis Deborah A. , Desmond John E.
Published: June 2008

Classical conditioning paradigms, such as trace conditioning, in which a silent period elapses between the offset of the conditioned stimulus (CS) and the delivery of the unconditioned stimulus (US), and delay conditioning, in which the CS and US coterminate, are widely used to study the neural substrates of associative learning. However, there are significant gaps in our knowledge of the neural systems underlying conditioning in humans. For example, evidence from animal and human patient research suggests that the hippocampus plays a critical role during trace eyeblink conditioning, but there is no evidence to date in humans that the hippocampus is active during trace eyeblink conditioning or is differentially responsive to delay and trace paradigms. The present work provides a direct comparison of the neural correlates of human delay and trace eyeblink conditioning by using functional MRI. Behavioral results showed that humans can learn both delay and trace conditioning in parallel. Comparable delay and trace activation was measured in the cerebellum, whereas greater hippocampal activity was detected during trace compared with delay conditioning. These findings further support the position that the cerebellum is involved in both delay and trace eyeblink conditioning whereas the hippocampus is critical for trace eyeblink conditioning. These results also suggest that the neural circuitry supporting delay and trace eyeblink classical conditioning in humans and laboratory animals may be functionally similar.
Evolution of tRNA nucleotidyltransferases: A small deletion generated CC-adding enzymes
Authors: Neuenfeldt Anne , Just Andrea , Betat Heike , Mörl Mario
Published: June 2008

CCA-adding enzymes are specialized polymerases that add a specific sequence (C-C-A) to tRNA 3′ ends without requiring a nucleic acid template. In some organisms, CCA synthesis is accomplished by the collaboration of evolutionary closely related enzymes with partial activities (CC and A addition). These enzymes carry all known motifs of the catalytic core found in CCA-adding enzymes. Therefore, it is a mystery why these polymerases are restricted in their activity and do not synthesize a complete CCA terminus. Here, a region located outside of the conserved motifs was identified that is missing in CC-adding enzymes. When recombinantly introduced from a CCA-adding enzyme, the region restores full CCA-adding activity in the resulting chimera. Correspondingly, deleting the region in a CCA-adding enzyme abolishes the A-incorporating activity, also leading to CC addition. The presence of the deletion was used to predict the CC-adding activity of putative bacterial tRNA nucleotidyltransferases. Indeed, two such enzymes were experimentally identified as CC-adding enzymes, indicating that the existence of the deletion is a hallmark for this activity. Furthermore, phylogenetic analysis of identified and putative CC-adding enzymes indicates that this type of tRNA nucleotidyltransferases emerged several times during evolution. Obviously, these enzymes descend from CCA-adding enzymes, where the occurrence of the deletion led to the restricted activity of CC addition. A-adding enzymes, however, seem to represent a monophyletic group that might also be ancestral to CCA-adding enzymes. Yet, experimental data indicate that it is possible that A-adding activities also evolved from CCA-adding enzymes by the occurrence of individual point mutations.