bluuebunny/crossref_metadata_2025 huggingface dataset:
The single nucleotide polymorphism upstream of insulin-induced gene 2 (INSIG2) is associated with the prevalence of hypercholesterolaemia, but not with obesity, in Japanese American women
Authors: Oki Kenji , Yamane Kiminori , Kamei Nozomu , Asao Takako , Awaya Tomokazu , Kohno Nobuoki
Published: June 2008

Insulin-induced gene 2 (insig-2) protein is known to play important roles in cholesterol and TAG metabolism bothin vivoandin vitro. One particularly interesting single nucleotide polymorphism (SNP), rs7566605, located 10 kb upstream ofINSIG2was reported to have the strongest association with obesity among 86 604 SNP, while the relationship with dyslipidaemia is uncertain. Eight hundred and eighty-five Japanese Americans (347 men and 538 women) and 378 Japanese (182 men and 196 women) were enrolled, and the rs7566605 SNP, which is consistent with either G or C, was determined. We investigated the association between the rs7566605 SNP and the prevalence of hypercholesterolaemia or hypertriacylglycerolaemia, or obesity parameters, as assessed by BMI, waist girth and percentage body fat. There were no significant differences in BMI, waist girth and percentage body fat according to the genotype in each of the four groups, which was divided by population and sex. The prevalence of hypercholesterolaemia was significantly different between the genotypes in Japanese American female subjects (GG, 62·2 %; GC, 57·1 %; CC, 42·1 %;P = 0·021), but not in the other subjects. In Japanese American women, the subjects with the CC genotype had a 0·43-fold decreased risk (95 % CI 0·24, 0·80) for hypercholesterolaemia compared with the GG genotype after adjustment for age, percentage body fat, smoking status and hormone replacement therapy. The CC genotype of the rs7566605 SNP is suggested to be a protective genetic factor against the progression of hypercholesterolaemia on a high-fat diet, especially in Japanese female subjects.
Hypolipidaemic effect of maize starch with different amylose content in ovariectomized rats depends on intake amount of resistant starch
Authors: Liu Xiong , Ogawa Hiroshi , Kishida Taro , Ebihara Kiyoshi
Published: June 2008

The effect of amylose content on digestibility of starch in the small intestine and on the concentration of plasma lipid were studied in ileorectostomized rats and in ovariectomized rats, respectively. Seven kinds of starch with different amylose content (0, 27, 54, 62, 76, 79, 86 %) were used as test starch, which contained 0·4, 5·6, 37·1, 40·2, 45·6, 36·9 and 36·1 % resistant starch (RS), respectively. Rats were fed one of test diets containing 30 % test starch with different amylose content for 14 d in ileorectostomized and for 21 d in ovariectomized rats. Food intake was not significantly different among the groups. In ileorectostomized rats, the small intestinal starch digestibility decreased with increasing intakes of amylose and RS. In ovariectomized rats, body weight gain was lower on the higher amylose maize starch diets. The concentrations of plasma TAG and cholesterol decreased with increasing intake of RS. The concentrations of liver total lipids and TAG decreased with increasing intake of RS, but that of liver cholesterol did not. There was significant positive correlation between the level of sterol regulatory element-binding protein-1c mRNA and concentration of liver TAG. Total SCFA amount in the caecum increased logarithmically with increasing dry weight of caecal contents. The amount of bile acids in the small intestinal content and the excretions of bile acids and neutral steroids in faeces increased with increasing RS intake. These results show that starch rich in RS is more effective in preventing ovarian hormone deficiency-induced hyperlipidaemia.
Vitamin E supplementation may transiently increase tuberculosis risk in males who smoke heavily and have high dietary vitamin C intake – reply by Hemilä & Kaprio
Authors: Hemilä Harri , Kaprio Jaakko
Published: June 2008

Randomisation of participants in two study groups leads to groups that have baseline differences accountable by the play of chance. In small trials, the random variation between two study groups can be large, but in large studies the variation is typically small.
Laying hens can convert high doses of folic acid added to the feed into natural folates in eggs providing a novel source of food folate
Authors: Hoey Leane , McNulty Helene , McCann Elizabeth M. E. , McCracken Kelvin J. , Scott John M. , Marc Barbara Blaznik , Molloy Anne M. , Graham Ciaren , Pentieva Kristina
Published: June 2008

There are few good sources of natural food folates apart from green leafy vegetables and these may have a limited potential to increase folate status because of substantial losses that can occur during cooking. Fortified foods can overcome this but are controversial because of safety concerns regarding chronic exposure to high-dose folic acid (FA; the synthetic form). The aim of the present study was to develop eggs with an enriched natural folate content and minimal unmetabolised FA. Forty-eight, 30-week-old laying hens were randomised to receive the basal feed (formulated to provide 1 mg folate/kg feed) to which had been added one of the following FA levels (0, 2, 4, 8, 16, 32 mg/kg feed). Total folate was measured in eggs collected throughout the 12-week study period and the FA content estimated at 12 weeks. Results showed that the maximal egg folate content was achieved by adding 16 mg FA/kg feed. At this optimal dose, the total folate content per egg was 75 μg (compared with 32 μg in a regular egg) of which FA represented at most 10 %, a level which would probably be converted into natural folates by humans after ingestion. The results demonstrate that it is possible to use synthetic FA at high doses to produce novel animal foods enriched with natural folates in a cost-efficient process. Such foods may be particularly relevant to European populations without access to FA fortification and therefore dependent on natural food folate sources for the primary prevention of folate-related disease.
A mechanism for self-generated magnetic fields in the interaction of ultra-intense laser pulses with thin plasma targets
Authors: ABUDUREXITI A. , OKADA T. , ISHIKAWA S.
Published: June 2008

In the study of the interaction of ultra-intense laser pulses with thin plasma targets there appears self-generated magnetic fields in the plasma target. The strong magnetic fields were directly measured in the plasma target, and were attributed to a mechanism of non-parallel electron temperature and density gradients. These magnetic fields can become strong enough to significantly affect the plasma transport. The underlying mechanism of the self-generated magnetic fields in the ultra-intense laser–plasma interactions is presented by using a two-dimensional particle-in-cell simulation.
Decision making and problem solving in adolescents who deliberately self-harm
Authors: Oldershaw A. , Grima E. , Jollant F. , Richards C. , Simic M. , Taylor L. , Schmidt U.
Published: June 2008

Background

Healthy adolescents, and adults who engage in reward-driven, risky behaviours, demonstrate poor decision-making ability. Decision making in deliberate self-harm (DSH), a reward-driven, high-risk behaviour, has received little attention. This study assessed decision making and problem solving in adolescents with current or past SH.

Method

Decision making and problem solving were assessed using the Iowa Gambling Task (IGT) and the Means–Ends Problem-Solving Procedure (MEPS) respectively in 133 adolescents (57 healthy and 22 depressed controls with no SH history and 54 with SH history). A second analysis separated the SH group into current (n=30) and past (n=24) SH.

Results

The collective performance of adolescents with SH history did not differ from depressed or healthy adolescents on the IGT. However, current self-harming adolescents had a trend towards more high-risk choices (p=0.06) than those with previous SH history and were the only group not to significantly improve over time, persisting with high-risk strategy throughout. Those who no longer self-harmed learnt to use a low-risk strategy similar to healthy and depressed controls. Recency of last SH episode correlated with IGT performance. Depressed participants performed well on the IGT but poorly on the MEPS. By contrast, both collective and divided SH groups had comparable MEPS scores to healthy controls, all performing better than depressed participants.

Conclusion

Poor decision making is present in adolescents who currently self-harm but not in those with previous history; improvement in decision-making skills may therefore be linked to cessation of self-harm. Depressed adolescents who do and do not self-harm may have distinct characteristics.
Continuity of care in mental health: understanding and measuring a complex phenomenon
Authors: Burns T. , Catty J. , White S. , Clement S. , Ellis G. , Jones I. R. , Lissouba P. , McLaren S. , Rose D. , Wykes T.
Published: June 2008

Background

Continuity of care is considered by patients and clinicians an essential feature of good quality care in long-term disorders, yet there is general agreement that it is a complex concept. Most policies emphasize it and encourage systems to promote it. Despite this, there is no accepted definition or measure against which to test policies or interventions designed to improve continuity. We aimed to operationalize a multi-axial model of continuity of care and to use factor analysis to determine its validity for severe mental illness.

Method

A multi-axial model of continuity of care comprising eight facets was operationalized for quantitative data collection from mental health service users using 32 variables. Of these variables, 22 were subsequently entered into a factor analysis as independent components, using data from a clinical population considered to require long-term consistent care.

Results

Factor analysis produced seven independent continuity factors accounting for 62.5% of the total variance. These factors,Experience and Relationship, Regularity,Meeting Needs,Consolidation,Managed Transitions,Care CoordinationandSupported Living, were close but not identical to the original theoretical model.

Conclusions

We confirmed that continuity of care is multi-factorial. Our seven factors are intuitively meaningful and appear to work in mental health. These factors should be used as a starting-point in research into the determinants and outcomes of continuity of care in long-term disorders.
The absorption theorem for affable equivalence relations
Authors: GIORDANO THIERRY , MATUI HIROKI , PUTNAM IAN F. , SKAU CHRISTIAN F.
Published: June 2008

We prove a result about extension of a minimal AF-equivalence relation R on the Cantor set X, the extension being ‘small’ in the sense that we modify R on a thin closed subset Y of X. We show that the resulting extended equivalence relation S is orbit equivalent to the original R, and so, in particular, S is affable. Even in the simplest case—when Y is a finite set—this result is highly non-trivial. The result itself—called the absorption theorem—is a powerful and crucial tool for the study of the orbit structure of minimal ℤn-actions on the Cantor set, see Remark 4.8. The absorption theorem is a significant generalization of the main theorem proved in Giordano et al [Affable equivalence relations and orbit structure of Cantor dynamical systems. Ergod. Th. & Dynam. Sys.24 (2004), 441–475] . However, we shall need a few key results from the above paper in order to prove the absorption theorem.
Cyclicity of period annuli and principalization of Bautin ideals
Authors: GAVRILOV LUBOMIR
Published: June 2008

Let Π be an open period annulus of a plane analytic vector field X0. We prove that the maximal number of limit cycles which bifurcate from Π under a given multi-parameter analytic deformation Xλ of X0 is the same as in an appropriate one-parameter analytic deformation Xλ(ε), provided that this cyclicity is finite. Along the same lines, we also give a bound for the cyclicity of homoclinic saddle loops.
Sectional-hyperbolic systems
Authors: METZGER R. , MORALES C.
Published: June 2008

We introduce a class of vector fields onn-manifolds containing the hyperbolic systems, the singular-hyperbolic systems on 3-manifolds, the multidimensional Lorenz attractors and the robust transitive singular sets in Liet al[Robust transitive singular sets via approach of an extended linear Poincaré flow.Discrete Contin. Dyn. Syst.13(2) (2005), 239–269]. We prove that the closed orbits of a system in such a class are hyperbolic in a persistent way, a property which is false for higher-dimensional singular-hyperbolic systems. We also prove that the singularities in the robust transitive sets in Liet alare similar to those in the multidimensional Lorenz attractor. Our results will give a partial negative answer to Problem 9.26 in Bonattiet al[Dynamics Beyond Uniform Hyperbolicity. A Global Geometric and Probabilistic Perspective (Encyclopaedia of Mathematical Sciences, 102. Mathematical Physics, III). Springer, Berlin, 2005].
NEAR-INTEGRATED RANDOM COEFFICIENT AUTOREGRESSIVE TIME SERIES
Authors: Aue Alexander
Published: June 2008

We determine the limiting behavior of near-integrated first-order random coefficient autoregressive RCA(1) time series. It is shown that the asymptotics of the finite-dimensional distributions crucially depends on how the critical value 1 is approached, which determines whether the process is near-stationary, has a unit root, or is mildly explosive. %In a second part, we derive the limit distribution of the serial correlation coefficient in the near stationary and the mildly explosive settings under very general conditions on the parameters. The results obtained are in accordance with those available for first-order autoregressive time series and can hence serve as an addition to existing literature in the area.
Making Representations: Modes and Strategies of Political Parties
Authors: Saward Michael
Published: June 2008

This article critically addresses the varied ways in which political parties can be said to represent. Three important ideal-typical modes of party representation are outlined: the popular, the statal, and the reflexive. Arguments are offered for countering the common view that, for example, popular modes are the most democratic, and statal modes the least democratic. Statal modes in particular are often taken to be an indicator of a decline in parties’ representative functions; however, shifting modes of party representation often have more to do with strategic choices and contextual pressures than democratic ideals. No one ideal-typical mode is intrinsically more democratic than others. Further, there is evidence that a new mode of party representation, the reflexive, may be emerging; parties may be transforming into something they never were in order to continue to do the things they have always sought to do. Whether democracy is unthinkable save for political parties is no longer the question we need to ask. Rather, we need to ask: what kinds of representative democracy are thinkable? And what forms of party claims, if any, are appropriate to them?
What Happens When Verbal Threat Information and Vicarious Learning Combine?
Authors: Askew Chris , Kessock-Philip Hannah , Field Andy P.
Published: June 2008

Recent research has shown that the verbal information and vicarious learning pathways to fear create long term fear cognitions and can create cognitive biases and avoidance in children. However, it is unlikely that these pathways operate in isolation in the aetiology of childhood fear and the interaction between these pathways is untested. Three preliminary experiments are reported that explore the combined effect of verbal threat information and vicarious learning on self-reported fear beliefs in 7–9-year-old children. Results showed that prior negative information significantly facilitated the effect of negative vicarious learning on children's fear beliefs (Experiment 1); however, there was not a significant combined effect of verbal threat information and vicarious learning when they the information was presented during (Experiment 2) or after (Experiment 3) vicarious learning. These results support the idea that verbal information can affect CS-US associations formed in subsequent vicarious learning events, but contradict the proposal that it can change fear beliefs already acquired through vicarious learning by changing how a person evaluates the vicarious learning episode.
Do Cognitive Models of Obsessive Compulsive Disorder Apply to Children and Adolescents?
Authors: Reynolds Shirley , Reeves Jenny
Published: June 2008

Cognitive models of obsessive compulsive disorder (OCD) have been influential in understanding and treating the disorder in adults. Cognitive models may also be applicable to children and adolescents and would have important implications for treatment. The aim of this systematic review was to evaluate research that examined the applicability of the cognitive model of OCD to children and adolescents. Inclusion criteria were set broadly but most studies identified included data regarding responsibility appraisals, thought-action fusion or meta-cognitive models of OCD in children or adolescents. Eleven studies were identified in a systematic literature search. Seven studies were with non clinical samples, and 10 studies were cross-sectional. Only one study did not support cognitive models of OCD in children and adolescents and this was with a clinical sample and was the only experimental study. Overall, the results strongly supported the applicability of cognitive models of OCD to children and young people. There were, however, clear gaps in the literature. Future research should include experimental studies, clinical groups, and should test which of the different models provide more explanatory power.
Massive Stars as Cosmic Engines Through the Ages
Authors: Maeder André , Meynet Georges , Ekström Sylvia , Hirschi Raphael , Georgy Cyril
Published: June 2008

Some useful developments in the model physics are briefly presented, followed by model results on chemical enrichments and WR stars. We discuss the expected rotation velocities of WR stars. We emphasize that the (C+O)/He ratio is a better chemical indicator of evolution for WC stars than the C/He ratios. With or without rotation, at a given luminosity the (C+O)/He ratios should be higher in regions of lower metallicity Z. Also, for a given (C+O)/He ratio the WC stars in lower Z regions have higher luminosities. The WO stars, which are likely the progenitors of supernovae SNIc and of some GRBs, should preferentially be found in regions of low Z and be the descendants of very high initial masses. Finally, we emphasize the physical reasons why massive rotating low Z stars may also experience heavy mass loss.
X-ray Emission from O Stars
Authors: Cohen David H.
Published: June 2008

Young O stars are strong, hard, and variable X-ray sources; properties that strongly affect their circumstellar and galactic environments. After ≈ 1 Myr, these stars settle down to become steady sources of soft X-rays. I will use high-resolution X-ray spectroscopy and MHD modeling to show that young O stars like θ1 Ori C are well explained by the magnetically channeled wind shock scenario. After their magnetic fields dissipate, older O stars produce X-rays via shock heating in their unstable stellar winds. Here too I will use X-ray spectroscopy and numerical modeling to confirm this scenario. In addition to elucidating the nature and cause of the O star X-ray emission, modeling of the high-resolution X-ray spectra of O supergiants provides strong evidence that mass-loss rates of these O stars have been overestimated.
Physical and Wind Properties of OB-Stars
Authors: Puls Joachim
Published: June 2008

In this review, the physical and wind properties of OB-stars are discussed, with particular emphasis on metallicity dependence and recent results from the flames survey of massive stars. We summarize the relation between spectral type and Teff, discuss the status quo of the “mass-discrepancy”, refer to the problem of “macro-turbulence” and comment on the distribution of rotational velocities. Observational constraints on the efficiency of rotational mixing are presented, and magnetic field measurements summarized. Wind properties are reviewed, and problems related to weak winds and wind-clumping highlighted.
The Metallicity Dependence of the Mass Loss of Early-Type Massive Stars
Authors: de Koter Alex
Published: June 2008

We report on a comprehensive study of the wind properties of 115 O- and early B-type stars in the Galaxy and the Large Magellanic Clouds. This work is part of the VLT/FLAMES Survey of Massive Stars. The data is used to construct the empirical dependence of the mass-loss in stellar winds on the metal content of their atmospheres. The metal content of early-type stars in the Magellanic Clouds is discussed. Assuming a power-law dependence of mass loss on metal content, Ṁ ∝ Zm, we find m = 0.83 ± 0.16 from an analysis of the wind momentum luminosity relation (Mokiem et al. 2007b). This result is in good agreement with the prediction m = 0.69 ± 0.10 by Vink et al. (2001). Though the scaling agrees, the absolute empirical value of mass loss is found to be a factor of two higher than predictions. This may be explained by a modest amount of clumping in the outflows of the objects studied.
Wolf-Rayet Wind Models from Hydrodynamic Model Atmospheres
Authors: Gräfener Götz , Hamann Wolf-Rainer
Published: June 2008

We present a parameter study of WR-type mass loss, based on the PoWR hydrodynamic model atmospheres. These new models imply that optically thick WR-type winds are generally formed close to the Eddington limit. This is demonstrated for the case of hydrogen rich WNL stars, which turn out to be extremely massive, luminous stars with progenitor masses above ≈ 80 M⊙. We investigate the dependence of WR-type mass loss on various stellar parameters, including the metallicity Z. The results depend strongly on the L/M ratio, the stellar temperature T*, and the assumed wind clumping. For high L/M ratios, strong WR-type winds can be maintained down to very low Z. Even for primordial massive stars we predict considerable mass loss if their surfaces are self-enriched by primary elements.
Luminous Blue Variables & Mass Loss near the Eddington Limit
Authors: Owocki Stan , van Marle Allard Jan
Published: June 2008

During the course of their evolution, massive stars lose a substantial fraction of their initial mass, both through steady winds and through relatively brief eruptions during their Luminous Blue Variable (LBV) phase. This talk reviews the dynamical driving of this mass loss, contrasting the line-driving of steady winds to the potential role of continuum driving for eruptions during LBV episodes when the star exceeds the Eddington limit. A key theme is to emphasize the inherent limits that self-shadowing places on line-driven mass loss rates, whereas continuum driving can in principle drive mass up to the “photon-tiring” limit, for which the energy to lift the wind becomes equal to the stellar luminosity. We review how the “porosity” of a highly clumped atmosphere can regulate continuum-driven mass loss, but also discuss recent time-dependent simulations of how base mass flux that exceeds the tiring limit can lead to flow stagnation and a complex, time-dependent combination of inflow and outflow regions. A general result is thus that porosity-mediated continuum driving in super-Eddington phases can explain the large, near tiring-limit mass loss inferred for LBV giant eruptions.
What Do We Really Know About the Winds of Massive Stars?
Authors: Hillier D. John
Published: June 2008

The standard theory of radiation driven winds has provided a useful framework to understand stellar winds arising from massive stars (O stars, Wolf-Rayet stars, and luminous blue variables). However, with new diagnostics, and advances in spectral modeling, deficiencies in our understanding of stellar winds have been thrust to the forefront of our research efforts. Spectroscopic observations and analyses have shown the importance of inhomogeneities in stellar winds, and revealed that there are fundamental discrepancies between predicted and theoretical mass-loss rates. For late O stars, spectroscopic analyses derive mass-loss rates significantly lower than predicted. For all O stars, observed X-ray fluxes are difficult to reproduce using standard shock theory, while observed X-ray profiles indicate lower mass-loss rates, the potential importance of porosity effects, and an origin surprisingly close to the stellar photosphere. In O stars with weak winds, X-rays play a crucial role in determining the ionization balance, and must be taken into account.
The Physical Properties of Red Supergiants: Comparing Theory and Observations
Authors: Massey Philip , Levesque Emily M. , Plez Bertrand , Olsen Knut A. G.
Published: June 2008

Red supergiants (RSGs) are an evolved stage in the life of intermediate massive stars (≤ 25 M⊙). For many years, their location in the H-R diagram was at variance with the evolutionary models. Using the MARCS stellar atmospheres, we have determined new effective temperatures and bolometric luminosities for RSGs in the Milky Way, LMC, and SMC, and our work has resulted in much better agreement with the evolutionary models. We have also found evidence of significant visual extinction due to circumstellar dust. Although in the Milky Way the RSGs contribute only a small fraction (< 1%) of the dust to the interstellar medium (ISM), in starburst galaxies or galaxies at large look-back times, we expect that RSGs may be the main dust source. We are in the process of extending this work now to RSGs of higher and lower metallicities using the galaxies M31 and WLM.
The Evolutionary State of the Cool Hypergiants – Episodic Mass Loss, Convective Activity and Magnetic Fields
Authors: Humphreys Roberta M.
Published: June 2008

The evolved cool stars near the empirical upper luminosity boundary in the HR Diagram all show evidence for considerable instability perhaps due to their proximity to this stability limit and/or their evolutionary state. Recent high resolution imaging and spectroscopy of several of these stars have revealed a subset characterized by complex ejecta and evidence for episodic mass loss driven by convective activity and magnetic fields. This group includes famous stars such as the red supergiants VY CMa, NML Cyg and the post RSG IRC +10420. I will review the observational evidence and discuss the implications for the final stages of these evolved stars, their mass loss mechanism, and evolutionary state.
Can Pulsational Instabilities Impact a Massive Star's Rotational Evolution?
Authors: Townsend Rich , MacDonald Jim
Published: June 2008

We investigate whether angular momentum transport due to unstable pulsation modes can play a significant role in the rotational evolution of massive stars. We find that these modes can redistribute appreciable angular momentum, and moreover trigger shear-instability mixing in the molecular weight gradient zone adjacent to stellar cores, with significant evolutionary impact.
Stellar Evolution at Low Metallicity
Authors: Hirschi Raphael , Chiappini Cristina , Meynet Georges , Maeder André , Ekström Sylvia
Published: June 2008

Massive stars played a key role in the early evolution of the Universe. They formed with the first halos and started the re-ionisation. It is therefore very important to understand their evolution. In this review, we first recall the effect of metallicity (Z) on the evolution of massive stars. We then describe the strong impact of rotation induced mixing and mass loss at very low Z. The strong mixing leads to a significant production of primary 14N, 13C and 22Ne. Mass loss during the red supergiant stage allows the production of Wolf-Rayet stars, type Ib,c supernovae and possibly gamma-ray bursts (GRBs) down to almost Z = 0 for stars more massive than 60 M⊙. Galactic chemical evolution models calculated with models of rotating stars better reproduce the early evolution of N/O, C/O and 12C/13C. Finally, the impact of magnetic fields is discussed in the context of GRBs.
Core Overshoot and Nonrigid Internal Rotation of Massive Stars: Current Status from Asteroseismology
Authors: Aerts Conny
Published: June 2008

Seismic estimates of core overshoot have been derived from extensive high-precision photometric and spectroscopic ground-based (multisite) campaigns for five main-sequence B-type stars. For three of these, the ratio of the near-core rotation frequency to the surface rotation frequency could be estimated as well, from the identified oscillation modes. We summarise these seismic results obtained for B stars. Now that the technique of asteroseismology was proven to work for probing the interior of massive stars, we expect a drastic increase in the precision of the structure parameters from the space missions CoRoT and Kepler, as well as from currently ongoing ground-based campaigns, in the coming years.
Metallicity Studies in the IR: Unveiling Obscured Clusters of Our Galaxy
Authors: Najarro Francisco
Published: June 2008

We review direct and indirect methods to derive metallicity through infrared spectroscopy of massive stars. The choice of different spectral types to obtain abundances allows to trace metallicity for a wide range of ages of the cluster hosting the massive stars. These methods have a great potential to understand the evolution of large amount of heavily obscured galactic clusters, which are currently being discovered through infrared surveys.
UCHII Regions and Newly Born O-type Stars
Authors: Conti Peter S. , Rho Jeonghee , Furness James , Crowther Paul A.
Published: June 2008

We have obtainedSpitzerIRAC and MIPS mid-IR images of a sample of 43 radio selected UCHII region sources to ascertain (a) whether the newly born O stars within are found with other stars in their birthplaces and (b) the nature of the surroundings. 37 of the sources appear to be in small clusters, and 33 are found in connection with other hot star formation activity. Thus, for the most part, O stars are not born in isolation. Here we give examples of the mid-IR images of the various types of UCHII regions.
Binary Populations and Stellar Dynamics in Young Clusters
Authors: Vanbeveren D. , Belkus H. , Van Bever J. , Mennekens N.
Published: June 2008

We first summarize work that has been done on the effects of binaries on theoretical population synthesis of stars and stellar phenomena. Next, we highlight the influence of stellar dynamics in young clusters by discussing a few candidate UFOs (unconventionally formed objects) like intermediate mass black holes, η Car, ζ Pup, γ2 Velorum and WR 140.
Westerlund 1 as a Template for Massive Star Evolution
Authors: Negueruela Ignacio , Clark J. Simon , Hadfield Lucy J. , Crowther Paul A.
Published: June 2008

With a dynamical mass Mdyn ~ 1.3×105 M⊙ and a lower limit Mcl > 5 × 104 M⊙ from star counts, Westerlund 1 is the most massive young open cluster known in the Galaxy and thus the perfect laboratory to study massive star evolution. We have developed a comprehensive spectral classification scheme for supergiants based on features in the 6000–9000Å range, which allows us to identify > 30 very luminous supergiants in Westerlund 1 and ~ 100 other less evolved massive stars, which join the large population of Wolf-Rayet stars already known. Though detailed studies of these stars are still pending, preliminary rough estimates suggest that the stars we see are evolving to the red part of the HR diagram at approximately constant luminosity.
One Hundred 30 Dors?
Authors: Hanson M. M. , Popescu B.
Published: June 2008

There are a few ways to estimate the number of massive open clusters expected in the disk of the Milky Way, such as the total star formation rate of the Galaxy, or the open cluster mass function extrapolated to include the entire Galaxy. Surprisingly, they give similar predictions: the Milky Way should contain about 100 clusters as massive as 30 Doradus. Are we seeing them? We look closely at these predictions and compare them to what has been found so far in our Galaxy. We present sophisticated image simulations our group is developing to estimate the selection biases faced by current infrared searches for these massive clusters.
VLT/FORS Surveys of Wolf-Rayet Stars in the Nearby Universe
Authors: Hadfield Lucy J. , Crowther Paul A.
Published: June 2008

We present results from a series of VLT/FORS narrow-band imaging and spectroscopic surveys of Wolf-Rayet (WR) stars in nearby spiral galaxies and compare observed populations in high- and low metallicity environments. The metal-rich galaxy M 83 is seen to host an exceptional WR content, with over 1000 WR stars being detected. N(WC)/N(WN) ~ 1.2 and late-type WC subtypes dominate the WC population. At low metallicity, ~100 stars has been identified within NGC 1313, with N(WC)/N(WN) ~ 0.5. In contrast to M83, the WC population of NGC 1313 comprises solely early subtypes plus a WO star (the first WO star to be identified beyond the Local Group). Consequently, the dominant WC subtype may serve as a crude metallicity diagnostic for WR galaxies.

In addition, the WR content of the blue compact dwarf galaxy NGC 3125 is examined. Previous UV and optical spectroscopic studies of knot A in NGC 3125 derive WR populations which differ by more than an order of magnitude. New VLT observations and archival HST spectroscopy reconcile this discrepancy via the use of LMC WR spectral templates and a reduced nebular-derived interstellar extinction. Empirical N(WR)/N(O) ratios for clusters within NGC 3125 are a factor of two higher than evolutionary synthesis predictions but are consistent with those observed for other young massive clusters.
Bubbles and Superbubbles: Observations and Theory
Authors: Chu You-Hua
Published: June 2008

Massive stars inject energy into the surrounding medium and form shell structures. Bubbles are blown by fast stellar winds from individual massive stars, while superbubbles are blown by fast stellar winds and supernova explosions from groups of massive stars. Bubbles and superbubbles share a similar overall structure: a swept-up dense shell with an interior filled by low-density hot gas. Physical properties of a bubble/superbubble can be affected by magnetic field, thermal conduction, turbulent mixing, inhomogeneous ambient medium, etc. I will review recent progresses on observations and compare them to theoretical expectations for (1) swept-up dense shells, (2) hot interiors, and (3) interface between a dense shell and its interior hot gas.
The Evolution of the Circumstellar and Interstellar Medium Around Massive Stars
Authors: Arthur S. Jane
Published: June 2008

Throughout their lives massive stars modify their environment through their ionizing photons and strong stellar winds. Here, I present coupled radiation-hydrodynamic calculations of the evolution of the bubbles and nebulae surrounding massive stars. The evolution is followed from the main sequence through the Wolf-Rayet stage and shows that structures are formed in the ISM out to some tens of parsecs radius. Closer to the star, instabilities lead to the breakup of swept-up wind shells. The photoevaporated flows from the resulting clumps interact with the stellar wind from the central star, which leads to the production of soft X-rays. I examine the consequences for the different observable structures at all time and size scales and evaluate the impact that the massive star has on its environment.
Stellar Feedback Through Cosmic Time: Starbursts & Superwinds
Authors: Dopita Michael A.
Published: June 2008

Throughout cosmic time, the feedback of massive star winds and supernova explosions has been instrumental in determining the phase structure of the interstellar medium, controlling important aspects of both the formation and evolution of galaxies, producing galactic winds and enriching the intergalactic medium with heavy elements. In this paper, I review progress made in our theoretical understanding of how these feedback processes have operated throughout cosmic time from the epoch of the first stars through to the present day.
Gemini/IFU Observations of Galactic Outflows in Starburst Galaxies
Authors: Smith Linda J. , Westmoquette Mark S.
Published: June 2008

We present Gemini/IFU observations that sample the roots of the galactic wind outflows in the starburst galaxies NGC 1569 and M82. The good spatial and spectral resolutions of these observations allow us to probe the interactions of cluster winds with their environments on small scales. For both galaxies, we find a ubiquitous broad (200–300 km s−1) Hα component underlying a brighter narrower component. By mapping the properties of the individual line components, we find correlations that suggest that the broad component results from powerful cluster wind-gas clump interactions. For NGC 1569, there is little evidence for organised gas flows within the central zone and we suggest that the flow-dominated wind must form well beyond the region containing the massive star clusters. For M82, we find that the kinematics of the wind base are very complex; the width of the broad component reaches values of > 350 km s−1 at the base of the wind, and the outflow itself rapidly becomes chaotic in the inner wind region.
The Role of Massive Stars in Galactic Chemical Evolution
Authors: Matteucci Francesca
Published: June 2008

I will review the role of massive stars in galactic evolution both from the nucleosynthesis and energetics point of view. In particular, I will highlight some important observational facts explained by means of massive stars in galaxies of different morphological type: the Milky Way, ellipticals and dwarf spheroidals. I will describe first the time-delay model and its interpretation in terms of abundance ratios in galaxies, then I will discuss the importance of mass loss in massive stars to reproduce the data in the Galactic bulge and disk. I will discuss also how massive stars can be important producers of primary nitrogen if rotation in stellar models is taken into account. Concerning elliptical galaxies, I will show that to reproduce the observed [Mg/Fe] versus Mass relation in these galaxies it is necessary to assume a more important role of massive stars in more massive galaxies and that this can be achieved by means of downsizing in star formation. I will discuss how massive stars are responsible in triggering galactic winds both in ellipticals and dwarf spheroidals. These latter systems show a low overabundance of α-elements relative to Fe with respect to Galactic stars of the same [Fe/H]: this is interpreted as due to a slow star formation coupled with very efficient galactic winds. Finally, I will show a comparison between the predicted Type Ib/c rates in galaxies and the observed GRB rate and how we can impose constraints on the mechanism of galaxy formation by studying the GRB rate at high redshift.
Detailed Nucleosynthesis Yields from the Explosion of Massive Stars
Authors: Fröhlich Carla , Fischer T. , Liebendörfer M. , Thielemann F.-K. , Truran J.W.
Published: June 2008

Despite the complexity and uncertainties of core collapse supernova simulations there is a need to provide correct nucleosynthesis abundances for the progressing field of galactic evolution and observations of low metallicity stars. Especially the innermost ejecta are directly affected by the explosion mechanism, i.e. most strongly the yields of Fe-group nuclei for which an induced piston or thermal bomb treatment will not provide the correct yields because the effect of neutrino interactions is not included.

Recent observations of metal-poor halo stars support the suggested existence of a lighter element primary process (LEPP) which operates very early in the galaxy and is independent of the r-process. We present a candidate for the LEPP, the so-called νp-process.
Core-Collapse Supernovae as Dust Producers
Authors: Kotak Rubina
Published: June 2008

Although it has long been hypothesised that core-collapse supernovae may produce large quantities of dust, interest in this problem has recently been rekindled given the enormous dust masses inferred at very high redshifts (z ≳ 6), when conventional low-mass dust-producing stars would fail to contribute significantly to the universal dust budget. Emission due to warm dust peaks at mid-IR wavelengths. However, with the notable exception of SN 1987A, supernova studies in the mid-IR have been virtually non-existent until the advent of the Spitzer Space Telescope. On behalf of the Mid-Infrared Supernova Consortium, I briefly discuss recent exciting results from mid-IR studies of core-collapse supernovae using Spitzer and attempt to put the role of supernovae as major dust producers into perspective.
GRBs as Probes of Massive Stars Near and Far
Authors: Fynbo Johan P. U. , Malesani Daniele
Published: June 2008

Long-duration gamma-ray bursts are the manifestations of massive stellar death. Due to the immense energy release they are detectable from most of the observable universe. In this way they allow us to study the deaths of single (or binary) massive stars possibly throughout the full timespan massive stars have existed in the Universe. GRBs provide a means to infer information about the environments and typical galaxies in which massive stars are formed. Two main obstacles remain to be crossed before the full potential of GRBs as probes of massive stars can be harvested: i) we need to build more complete and well understood samples in order not to be fooled by biases, and ii) we need to understand to which extent GRBs may be intrinsically biased in the sense that they are only formed by a limited subset of massive stars defined by most likely a restricted metallicity interval. I describe the status of an ongoing effort to build a more complete sample of long-duration GRBs with measured redshifts. Already now we can conclude that the environments of GRB progenitors are very diverse with metallicities ranging from solar to a hundredth solar and extinction ranging from none to AV > 5 mag. We have also identified a sightline with significant escape of Lyman continuum photons and another with a clear 2175 Å extinction bump.
The Connection between Gamma-Ray Bursts and Extremely Metal-Poor Stars as Nucleosynthetic Probes of the Early Universe
Authors: Nomoto K. , Tominaga N. , Tanaka M. , Maeda K. , Umeda H.
Published: June 2008

The connection between the long GRBs and Type Ic Supernovae (SNe) has revealed the interesting diversity: (i) GRB-SNe, (ii) Non-GRB Hypernovae (HNe), (iii) X-Ray Flash (XRF)-SNe, and (iv) Non-SN GRBs (or dark HNe). We show that nucleosynthetic properties found in the above diversity are connected to the variation of the abundance patterns of extremely-metal-poor (EMP) stars, such as the excess of C, Co, Zn relative to Fe. We explain such a connection in a unified manner as nucleosynthesis of hyper-aspherical (jet-induced) explosions of Pop III core-collapse SNe. We show that (1) the explosions with large energy deposition rate, Ėdep, are observed as GRB-HNe and their yields can explain the abundances of normal EMP stars, and (2) the explosions with small Ėdepare observed as GRBs without bright SNe and can be responsible for the formation of the C-rich EMP (CEMP) and the hyper metal-poor (HMP) stars. We thus propose that GRB-HNe and the Non-SN GRBs (dark HNe) belong to a continuous series of BH-forming massive stellar deaths with the relativistic jets of different Ėdep.
Imaging and Spectroscopy with the James Webb Space Telescope
Authors: Sonneborn George
Published: June 2008

The James Webb Space Telescope (JWST) is a large, infrared-optimized space telescope scheduled for launch in 2013. JWST will find the first stars and galaxies that formed in the early universe, connecting the Big Bang to our own Milky Way galaxy. JWST will peer through dusty clouds to see stars forming planetary systems, connecting the Milky Way to our own Solar System. JWST's instruments are designed to work primarily in the infrared range of 1 - 28 μm, with some capability in the visible range. JWST will have a large segmented mirror, ~6.5 m in diameter, and will be diffraction-limited at 2 μm (< 0.1 arcsec resolution). JWST will be placed in an L2 orbit about 1.5 million km from the Earth. The instruments will provide imaging, coronography, and multi-object and integral-field spectroscopy across the 1 - 28 μm wavelength range. The breakthrough capabilities of JWST will enable new studies of massive stars from the Milky Way to the early universe.
Symposium Summary
Authors: Leitherer Claus
Published: June 2008

I summarize the highlights of the conference. First I provide a brief history of the beach symposia series our massive star community has been organizing. Then I use most of my allocated space discussing what I believe are the main answered and open questions in the field. Finally I conclude with a perspective of the future of massive star research.
Evolution of Massive Stars at Low Metallicity
Authors: Meynet Georges , Walborn Nolan R. , Hunter Ian , Martayan Christophe , van Marle Allard Jan , Marchenko Sergey , Vink Jorick S. , Limongi Marco , Levesque Emily M. , Modjaz Maryam
Published: June 2008

This paper reports the contributions made on the occasion of the Special Session entitled “Evolution of Massive Stars at Low Metallicity” which was held on Sunday, December 9, 2007 in Kauai (USA).
Magnetic Massive Stars
Authors: Townsend Rich , Cohen David H. , Dessart Luc , Hubrig Swetlana , Nazé Yaël , Petit Véronique , ud-Doula Asif , Walborn Nolan R.
Published: June 2008

Magnetic fields are unexpected in massive stars, due to the absence of a sub-surface convective dynamo. However, advances in instrumentation over the past three decades have led to their detection in a small but growing subset of these stars. Moreover, complementary theoretical developments have highlighted their potentially significant influence over the structure, evolution and circumstellar environments of massive stars. Here, we summarize a special session convened prior to the main conference, focused on presenting recent developments in the study of massive-star magnetic fields.
Prävalenz und Ursachen von Anämien in einer städtischen Hausarztpraxis
Authors: Merlo Ch. M. , Wuillemin W.A.
Published: June 2008

Eine Anämie nach WHO-Kriterien wurde bei 6% von 854 konsekutiven Patientinnen und Patienten in einer städtischen, internistischen Hausarztpraxis gefunden. Die Anämieabklärung erfolgte durch Anamnese und je nach klinischer Situation und mittlerem korpuskulärem Volumen (MCV) durch eine selektive Laborabklärung bestehend aus Retikulozytenzahl, Ferritin inklusive CRP, Serum-Vitamin-B12, Serum- oder Erythrozyten(Ez)-Folsäure und Serum-Kreatinin. Das mediane Alter der Anämiepatienten betrug 77 Jahre. Am häufigsten (21%) wurde eine chronische Niereninsuffizienz als Ursache der Anämie gefunden (renale Anämie). Entsprechend dem hohen Patientenalter waren Eisenmangel, chronische Erkrankung und Tumoren ebenfalls häufige Anämieursachen. Die Resultate werden mit den spärlich vorhandenen Literaturdaten aus Hausarztpraxen verglichen und speziell auf dem Hintergrund der Anämie bei Betagten diskutiert.
Herzerkrankungen beim Kind: Indikationen zu Risikoabklärungen und Familienscreening
Authors: Pfammatter J.-P.
Published: June 2008

Für einige Herzerkrankungen im Kindesalter ist familiär gehäuftes Auftreten typisch. In diesen Fällen stellt sich die Frage nach einer Reihenuntersuchung der übrigen Familienmitglieder. Für die verschiedenen Formen von Kardiomyopathie sind Familiarität und Morbidität so bedeutsam, dass eine Untersuchung der erstgradig Verwandten empfohlen wird. Da diese Kardiomyopathien sich erst im Verlauf des Lebens manifestieren können, braucht es oft repetitive Untersuchungen, in der Regel mittels Echokardiographie. Für die primär elektrischen Erkrankungen, die so genannten Channelopathien, gilt ebenfalls, dass die häufige Familiarität und die hohe Morbidität eine Familienuntersuchung rechtfertigen; im Gegensatz zur den Kardiomyopathien genügt allerdings in der Regel die einmalige EKG-Abklärung der erstgradig Vewandten. Bei einem Indexfall von angeborenem Herzvitium in der Familie gibt es keine generelle Screening-Empfehlung, Familienmitglieder sollen nur bei klinischen Verdachtsmomenten untersucht werden.