bluuebunny/crossref_metadata_2025 huggingface dataset:
Seed characteristics and germination limitations in the highly invasive Fallopia japonica s.l. (Polygonaceae)
Authors: Engler Jan , Abt Kai , Buhk Constanze
Published: February 2011

The species in the Japanese knotweed complex (Fallopia japonica s.l. and its hybrids) are among the most invasive plants on earth. Their expansion and reproduction in the introduced range have been mostly due to vegetative reproduction, but observations of low seedling numbers and hybridization processes exist. Knowledge of factors affecting germination characteristics is essential if the risk of sexual reproduction is to be assessed, and its impact on the ability of the species to spread and adapt to different environments. This study aims to examine the germination success of Fallopia japonica s.l. seeds of different ages, quality, and storage conditions. Irrespective of age and even after natural overwintering in the soil, seeds germinated quite well (48–79%). Ungerminated seeds collected in autumn of 2008 were characterized by a low weight/length ratio (W/L), low nutrient concentrations, and a greenish tepal coloration. These differences may be due to alternative male taxa participating in the pollination process. Spring collected seeds were subject to strong predation by birds. In contrast to the high germination observed under laboratory conditions, seed germination or early establishment in the field was inhibited and only a few seedlings were observed. Although the factors that inhibit the establishment of mature seeds in the field remain unknown, there is a clear risk that sexual reproduction could gain importance in the future as a result of changing environmental conditions or genetic adaptation. Not only would this facilitate expansive dispersal by wind, but it might also increase the potential for further adaptation of the species complex.
Pseudotumoural soft tissue lesions of the hand and wrist: a pictorial review
Authors: Vanhoenacker Filip M. , Eyselbergs Michiel , Van Hul Erik , Van Dyck Pieter , De Schepper Arthur M.
Published: February 2011

Mimickers of soft tissue tumours in the hand and wrist are more frequent than true neoplastic lesions. Pseudotumours belong to a large and heterogeneous group of disorders, varying from normal anatomical variants, cystic lesions, post-traumatic lesions, skin lesions, inflammatory and infectious lesions, non-neoplastic vascular lesions, metabolic disorders (crystal deposition disease and amyloidosis) and miscellaneous disorders. Although the imaging approach to pseudotumoural lesions is often very similar to the approach to “true” soft tissue tumoral counterparts, further management of these lesions is different. Biopsy should be performed only in doubtful cases, when the diagnosis is unclear. Therefore, the radiologist plays a pivotal role in the diagnosis of these lesions. Awareness of the normal anatomy and existence and common imaging presentation of these diseases, in combination with relevant clinical findings (clinical history, age, location and skin changes), enables the radiologist to make the correct diagnosis in most cases, thereby limiting the need for invasive procedures.
Lessons for low‐income regions following the reduction in hypertension‐related maternal mortality in high‐income countries
Authors: Goldenberg Robert L. , McClure Elizabeth M. , MacGuire Emily R. , Kamath Beena D. , Jobe Alan H.
Published: February 2011

Objectives

To evaluate pre‐eclampsia/eclampsia‐associated maternal mortality in high‐income countries to understand better the potential improvements in pre‐eclampsia/eclampsia‐related mortality in low‐income countries.

Methods

We searched Medline, PubMed, and the Cochrane Database (1900–2010) using relevant search terms. Studies of the incidence of pre‐eclampsia/eclampsia and case fatality rates in various geographic regions were included. The incidence of pre‐eclampsia/eclampsia and the pre‐eclampsia/eclampsia‐associated case fatality rates are presented by location and year.

Results

Most declines in maternal mortality associated with pre‐eclampsia/eclampsia in high‐income countries occurred between 1940 and 1970 and were associated with a 90% reduction in the incidence of eclampsia and a 90% reduction in the case fatality rate in women with eclampsia. The most important interventions were widespread use of prenatal care with blood pressure and urine protein measurement, and increased access to hospital care for timely induction of labor or cesarean delivery for women with severe pre‐eclampsia or seizures.

Conclusions

A substantial reduction in pre‐eclampsia/eclampsia‐related mortality could be made in low‐income countries by widespread hypertension and proteinuria screening and early delivery of women with severe disease. Magnesium sulfate may reduce mortality, but should not be the cornerstone of maternal mortality reduction programs.
Peristaltic pumping of viscous fluid in an elastic tube
Authors: TAKAGI D. , BALMFORTH N. J.
Published: February 2011

A model is derived for long peristaltic waves propagating steadily down a fluid-filled, axisymmetric tube. The waves are driven by imposing a radial force of prescribed form on the tube. The resulting deformation of the tube wall is modelled using linear elasticity and the internal flow using the lubrication approximation. Numerical solutions for periodic wave trains and solitary waves are presented, along with asymptotic solutions at both small and large forcing amplitudes. Large-amplitude periodic waves are characterized by narrow blisters adjoining long occluded sections of the tube, whereas a solitary wave of strong contraction produces a long inflated bow wave that propels a large quantity of fluid. A measure of pumping efficacy is given by the ratio of the net fluid displacement to the power input, and is highest for a large-amplitude solitary wave.
Resonant excitation of trapped waves by Poincaré waves in the coastal waveguides
Authors: REZNIK G. M. , ZEITLIN V.
Published: February 2011

After having revisited the theory of linear waves in the rotating shallow-water model with a straight coast and arbitrary shelf/beach bathymetry, we undertake a detailed study of resonant interaction of free Poincaré waves with modes trapped in the coastal waveguide. We describe and quantify the mechanisms of resonant excitation of waveguide modes and their subsequent nonlinear saturation. We obtain the modulation equations for the amplitudes of excited waveguide modes in the absence and in the presence of spatial modulation and analyse their solutions. Different saturation regimes are exhibited, depending on the nature of the modes involved. The excitation is proved to be efficient, i.e. the saturated amplitudes of the excited waves considerably exceed the amplitude of the generator waves. Back-influence of the excited waveguide modes onto the open ocean results in a phase shift of the reflected Poincaré waves and possible energy redistribution between them. A comparison of rotating and non-rotating cases displays substantial differences in excitation mechanisms in the two cases.
Improving the dietary intake of frail older people
Authors: Leslie W. S.
Published: February 2011

As a population subgroup, older people are more vulnerable to malnutrition especially those who are institutionalised. Recognition of deteriorating or poor nutritional status is key in reversing the effects of undernutrition and reinforces the value of regular weight checks and/or the use of screening tools. Commercially produced supplements are often the first option used to address undernutrition in both acute and community settings. They can be expensive and, although regularly prescribed, have undergone only limited evaluation of their effectiveness in community settings. An alternative but less researched approach to improve the nutritional status of undernourished people is food fortification. This approach may be particularly useful for older people, given their often small appetites. The ability to eat independently has been significantly related to decreased risk of undernutrition. Assisting people who have difficulty feeding themselves independently should become a designated duty and may be crucial in optimising nutritional status. Lack of nutrition knowledge has been identified as the greatest barrier to the provision of good nutritional care. Education and training of care staff are pivotal for the success of any intervention to address undernutrition. The development of undernutrition is a multi-factorial process and a package of approaches may be required to prevent or treat undernutrition. Nutrition must be at the forefront of care if national care standards are to be met.
Bioinformatic analysis of glycogen synthase kinase 3: human versus parasite kinases
Authors: OSOLODKIN DMITRY I. , ZAKHAREVICH NATALIA V. , PALYULIN VLADIMIR A. , DANILENKO VALERY N. , ZEFIROV NIKOLAY S.
Published: February 2011

Objective.Glycogen synthase kinase 3 (GSK-3) is a promising target for the treatment of various human diseases such as type 2 diabetes, Alzheimer's disease and inflammation. Successful inhibition of the homologues of this kinase inPlasmodium falciparum, Trypanosoma bruceiandLeishmania donovanimakes the kinase an attractive target for the treatment of malaria, trypanosomiasis and leishmaniasis, respectively. The aim of this work was to compare the binding sites of the GSK-3 kinases of different parasites and to analyse them as possible targets for therapeutic compounds.Methods.Both a sequence alignment and homology models of the structure of 21 different GSK-3 homologues belonging to mammals, insects, pathogenic fungi, nematodes, trematodes and protozoa have been analysed, 17 of them being studied for the first time.Results.The structure of the kinases and, in particular, their binding sites, were found to be rather conserved, possessing small insertions or deletions and conserved amino acid substitutions. Nevertheless, the kinases of most species of parasite did have some amino acid differences from the human kinase, which could be exploited for the design of selective drugs.Conclusion.Comparison of the human and parasite GSK-3 ATP binding site models has shown that the development of selective drugs affecting parasite GSK-3 is possible. Known inhibitors of human GSK-3 can also be used as starting scaffolds for the search for drugs acting against parasitic diseases.
Factors associated with symptoms of anxiety and depression in five cohorts of community-based older people: the HALCyon (Healthy Ageing across the Life Course) Programme
Authors: Gale C. R. , Sayer A. Aihie , Cooper C. , Dennison E. M. , Starr J. M. , Whalley L. J. , Gallacher J. E. , Ben-Shlomo Y. , Kuh D. , Hardy R. , Craig L. , Deary I. J. ,   the HALCyon Study Team
Published: February 2011

Background

Symptoms of anxiety and depression are common in older people, but the relative importance of factors operating in early and later life in influencing risk is unclear, particularly in the case of anxiety.

Method

We used data from five cohorts in the Healthy Ageing across the Life Course (HALCyon) collaborative research programme: the Aberdeen Birth Cohort 1936, the Caerphilly Prospective Study, the Hertfordshire Ageing Study, the Hertfordshire Cohort Study and the Lothian Birth Cohort 1921. We used logistic regression to examine the relationship between factors from early and later life and risk of anxiety or depression, defined as scores of 8 or more on the subscales of the Hospital Anxiety and Depression Scale, and meta-analysis to obtain an overall estimate of the effect of each.

Results

Greater neuroticism, poorer cognitive or physical function, greater disability and taking more medications were associated in cross-sectional analyses with an increased overall likelihood of anxiety or depression. Associations between lower social class, either in childhood or currently, history of heart disease, stroke or diabetes and increased risk of anxiety or depression were attenuated and no longer statistically significant after adjustment for potential confounding or mediating variables. There was no association between birth weight and anxiety or depression in later life.

Conclusions

Anxiety and depression in later life are both strongly linked to personality, cognitive and physical function, disability and state of health, measured concurrently. Possible mechanisms that might underlie these associations are discussed.
Then and now: evolving community in the context of a retirement village
Authors: BERNARD MIRIAM , LIDDLE JENNIFER , BARTLAM BERNADETTE , SCHARF THOMAS , SIM JULIUS
Published: February 2011

There is currently much debate in the United Kingdom policy and practice literature about how best to respond to the care and accommodation needs of people as they retire and grow older. Against a policy background which espouses the benefits of ‘lifetime homes and lifetime neighbourhoods’, the growth of purpose-built segregated retirement villages looks somewhat contradictory and is set to transform the housing scene. Whilst there has been considerable research into these environments in countries like the United States of America and Australia, we know comparatively little about what it is like to live in British retirement communities, how they evolve over time and whether they enhance people's lifestyle aspirations and quality of life. This paper examines these issues through the lens of ‘community’ and in the context of Denham Garden Village: a purpose-built retirement village in Buckinghamshire. Drawing on a range of qualitative data (from individual and group interviews, diaries and directives), we focus on how ‘community’ was conceptualised, experienced and understood both ‘then’ (in the early days of the village) and ‘now’ (subsequent to its redevelopment). The findings enable us to examine the extent to which ‘community’ evolves over time and raise important questions about how socially cohesive, or not, such retirement villages are.
Cross-national insights into the relationship between wealth and wellbeing: a comparison between Australia, the United States of America and South Korea
Authors: KIM SARANG , SARGENT-COX KERRY A. , FRENCH DAVINA J. , KENDIG HAL , ANSTEY KAARIN J.
Published: February 2011

The positive relationship between wealth and wellbeing has received considerable attention over the last three decades. However, little is known about how the significance of wealth for the health and wellbeing of older adults may vary across societies. Furthermore, researchers tend to focus mainly on income rather than other aspects of financial resources even though older adults often rely on fixed income, particularly after retirement. Using data from the Household, Income and Labour Dynamics in Australia (HILDA) survey (N=1,431), the Health and Retirement Study (HRS) in the United States of America (USA; N=4,687), and the Korean Longitudinal Study of Ageing (KLoSA; N=5,447), this exploratory cross-national study examined the relationship between wealth satisfaction and objective wealth and wellbeing (measured as self-rated health and life satisfaction) among older Australians, Americans and Koreans (50+ years). Regression analyses showed that wealth satisfaction was associated with wellbeing over and above monetary wealth in all three countries. The relationship between monetary wealth and self-rated health was larger for the US than Australian and Korean samples, while the additional contribution of wealth satisfaction to life satisfaction was larger for the Korean than the Australian and US samples. These findings are discussed in terms of the cultural and economic differences between these countries, particularly as they affect older persons.
The Hough transform
Authors: FOKKINGA MAARTEN
Published: February 2011

Suppose you are given a number of points in a plane and want to have those lines that each contain a large number of the given points. The Hough transform is a computerized procedure for that task. It was invented by Paul Hough (1962), originally to find the trajectories of subatomic particles in a bubble chamber, and it has even been patented. Nowadays, adaptations of the Hough transform are used, among others, for identification of transformed instances of a predefined figure, instead of just a line, in a digital picture. There are plenty of explanations on the Internet (use search key “Hough transform” and “generalized Hough transform”), some with nice applets to demonstrate the working (add search key “applet” or “demo”). Recently, Hart (2009) has looked back at the invention. We show how the original procedure could have been derived.
DUALIZABILITY OF GRAPHS
Authors: JOHANSEN SARAH M.
Published: February 2011

We investigate natural dualities for classes of simple graphs. For example, we give a natural duality for the class consisting of all n-colourable graphs and show that, for all n≥3, there is no natural duality for the class consisting of all freely n-colourable graphs. We also prove that there exist arbitrarily long finite chains of 3-colourable graphs that alternate between being dualizable and nondualizable.
Management of erythema and skin preservation; advice for patients
receiving radical radiotherapy to the breast: a systematic literature review
Authors: Butcher K. , Williamson K.
Published: February 2011

Objective: To systematically review and
critically appraise all evidence on skin care advice and products tailored for
patients receiving radical radiotherapy for breast cancer and to determine an
evidence-based conclusion regarding the most effective products.

Data Resources and Review Methods: Major
healthcare databases were searched with additional efforts made to hand-search
current journals. All relevant literature fulfilling the inclusion and exclusion
criteria was subjected to quality assurance checks. Those that passed underwent
a more rigorous appraisal and were included in the review.

Results: Ten studies were identified as
fulfilling the review criteria with regards to aims and quality. All were
randomised controlled trials; three were double-blinded, three were
single-blinded, the remaining were not blinded. Two addressed washing regimes,
two addressed deodorant use, whilst the six remaining studies investigated
creams, gels or dressings.

Conclusions: The results suggest that there is
a place for creams in the management and delay of radiation-induced skin
toxicities; however, research fails to highlight one product which has a
demonstrable benefit over others whilst still being cost effective and free from
adverse effects. Patients should not be discouraged from washing with water or
mild soaps and results suggest that the restriction of aluminium-free deodorant
during treatment is unnecessary; however, more research in this area is needed
with larger sample sizes.
Multidisciplinary integrated field campaign to an acidic Martian Earth analogue with astrobiological interest: Rio Tinto
Authors: Gómez F. , Walter N. , Amils R. , Rull F. , Klingelhöfer A.K. , Kviderova J. , Sarrazin P. , Foing B. , Behar A. , Fleischer I. , Parro V. , Garcia-Villadangos M. , Blake D. , Martin Ramos J.D. , Direito S. , Mahapatra P. , Stam C. , Venkateswaran K. , Voytek M.
Published: February 2011

Recently reported results from latest Mars Orbiters and Rovers missions are transforming our opinion about the red planet. That dry and inhospitable planet reported in the past is becoming a wetter planet with high probabilities of water existence in the past. Nowadays, some results seem to indicate the presence of water beneath the Mars surface. But also mineralogy studies by NASA Opportunity Rover report iron oxides and hydroxides precipitates on Endurance Crater. Sedimentary deposits have been identified at Meridiani Planum. These deposits must have generated in a dune aqueous acidic and oxidizing environment. Similarities appear when we study Rio Tinto, and acidic river under the control of iron.

The discovery of extremophiles on Earth widened the window of possibilities for life to develop in the Universe, and as a consequence on Mars and other planetary bodies with astrobiological interest. The compilation of data produced by the ongoing missions offers an interested view for life possibilities to exist: signs of an early wet Mars and rather recent volcanic activity as well as ground morphological characteristics that seem to be promoted by liquid water. The discovery of important accumulations of sulfates and the existence of iron minerals such as jarosite in rocks of sedimentary origin has allowed specific terrestrial models to come into focus. Río Tinto (Southwestern Spain, Iberian Pyritic Belt) is an extreme acidic environment, product of the chemolithotrophic activity of micro-organisms that thrive in the massive pyrite-rich deposits of the Iberian Pyritic Belt. Some particular protective environments should house the organic molecules and bacterial life forms in harsh environments such as Mars surface supporting microniches inside precipitated minerals or inside rocks. Terrestrial analogues could help us to afford the comprehension of habitability (on other planetary bodies).

We are reporting here the multidisciplinary study of some endolithic niches inside salt deposits used by phototrophs for taking advantage of sheltering particular light wavelengths. These acidic salts deposits located in Río Tinto shelter life forms that are difficult to visualize by eye. This interdisciplinary field analogue campaign was conducted in the framework of the CAREX FP7 EC programme.
Personalisation and Partnership: Competing Objectives in English Adult Social Care? The Individual Budget Pilot Projects and the NHS
Authors: Glendinning Caroline , Moran Nicola , Challis David , Fernández José-Luis , Jacobs Sally , Jones Karen , Knapp Martin , Manthorpe Jill , Netten Ann , Stevens Martin , Wilberforce Mark
Published: February 2011

As in other countries, improving collaboration between health and social care services is a long-established objective of English social policy. A more recent priority has been the personalisation of social care for adults and older people through the introduction of individualised funding arrangements. Individual budgets (IBs) were piloted in 13 English local authorities from 2005 to 2007, but they explicitly excluded NHS resources and services. This article draws on interviews with lead officers responsible for implementing IBs. It shows how the contexts of local collaboration created problems for the implementation of the personalisation pilots, jeopardised inter-sectoral relationships and threatened some of the collaborative arrangements that had developed over the previous decade. Personal budgets for some health services have subsequently also been piloted. These will need to build upon the experiences of the social care IB pilots, so that policy objectives of personalisation do not undermine previous collaborative achievements.
Gendering Welfare: Lone Mothers’ Experiences of Welfare-to-Work Programmes in Hong Kong
Authors: Hung Suet Lin , Fung Kwok Kin
Published: February 2011

Consideration of welfare regimes in Hong Kong has generally neglected gender and care work issues, focusing instead on welfare ideologies relating to production and the market orientation of social policies. In addition, traditional Chinese values place a high priority on motherhood. Drawing on qualitative interviews with lone mothers and social workers, this article considers welfare reform in Hong Kong from the late 1990s and the shift to welfare to work, examining these from the perspectives of gender. It suggests that as a result of the reforms there is a danger that lone mothers become double failures, as carers and workers.
Managing Disability Equality in Scotland: Tensions between Social Audit and Disability Equality
Authors: Arshad Rowena , Riddell Sheila
Published: February 2011

This paper focuses on the implications of adopting social audit approaches in order to implement equality policies in Scotland, exploring the tension between surface compliance and deep institutional engagement. Drawing on data from an evaluation of pubic sector bodies’ disability equality schemes, the paper provides examples of different levels of engagement, ranging from surface compliance (some education authorities) to institutional permeation of an equalities ethos (the Scottish Arts Council). The paper concludes by considering the future potential of single equality schemes to promote equality across Scottish society. It is argued that unless there is stronger support and challenge from Scottish government, there is a danger that equality schemes may become paper exercises rather than opportunities for institutional reflection and planning. At the same time, it would be a mistake to dismiss equality planning as merely an exercise in managerialism, since measuring the extent of inequality over time is an essential first step in the long process of achieving institutional change.
Mainstreaming the Disability Equality Duty and the Impact on Public Authorities' Working Practices
Authors: Pearson Charlotte , Watson Nick , Stalker Kirsten , Ferrie Jo , Lepiniere Jennifer , Paterson Kevin
Published: February 2011

Implemented as part of the 2005 amendments to the Disability Equality Act, the Disability Equality Duty (DED) placed new and important demands on public sector bodies. All such organisations are required to develop policies and working practices which actively promote the equality of disabled people as employees, consumers or visitors. The promotion of equality has to be proactive as opposed to reactive and must be mainstreamed into the normal day-to-day activities of organisational working practices. Whilst the DED follows on from the framework of previous anti-discrimination legislation set in place over the last 15 years, it represents a significant change in equality legislation and demands that public sector bodies instigate fundamental changes in their approach towards disability. This article reports on the initial stages of the implementation process of the DED across a range of public sector organisations in England, focussing in particular on how this policy has impacted on mainstreaming. Discussion shows that although organisations show awareness of mainstreaming and its implications for disability equality, there is limited evidence to suggest that the public sector has fully embraced this agenda.
Hadronic jet models today
Authors: Sikora Marek
Published: February 2011

The matter content of relativistic jets in AGNs is dominated by a mixture of protons, electrons, and positrons. During dissipative events these particles tap a significant portion of the internal and/or kinetic energy of the jet and convert it into electromagnetic radiation. While leptons – even those with only mildly relativistic energies – can radiate efficiently, protons need to be accelerated up to energies exceeding 1016–19 eV to dissipate radiatively a significant amount of energy via either trigerring pair cascades or direct synchrotron emission. Here I review various constraints imposed on the role of hadronic non-adiabatic cooling processes in shaping the high energy spectra of blazars. It will be argued that protons, despite being efficiently accelerated and presumably playing a crucial role in jet dynamics and dissipation of the jet kinetic energy to the internal energy of electrons and positrons, are more likely to remain radiatively passive in AGN jets.
Jets at lowest mass accretion rates
Authors: Maitra Dipankar , Cantrell Andrew , Markoff Sera , Falcke Heino , Miller Jon , Bailyn Charles
Published: February 2011

We present results of recent observations and theoretical modeling of data from black holes accreting at very low luminosities (L/LEdd≲ 10−8). We discuss our newly developed time-dependent model for episodic ejection of relativistic plasma within a jet framework, and a successful application of this model to describe the origin of radio flares seen in Sgr A*, the Galactic center black hole. Both the observed time lags and size-frequency relationships are reproduced well by the model. We also discuss results from new Spitzer data of the stellar black hole X-ray binary systemA0620–00. Complemented by long term SMARTS monitoring, these observations indicate that once the contribution from the accretion disk and the donor star are properly included, the residual mid-IR spectral energy distribution ofA0620–00 is quite flat and consistent with a non-thermal origin. The results above suggest that a significant fraction of the observed spectral energy distribution originating near black holes accreting at low luminosities could result from a mildly relativistic outflow. The fact that these outflows are seen in both stellar-mass black holes as well as in supermassive black holes at the heart of AGNs strengthens our expectation that accretion and jet physics scales with mass.
The influence of collimation on the appearance of relativistic jets
Authors: Petrucci Pierre-Olivier , Boutelier Timothe , Henri Gilles
Published: February 2011

The question of the collimation of relativistic jets is the subject of a lively debate in the community. We numerically compute the apparent velocity and the Doppler factor of a non homokinetic jet using different velocity profile, to study the effect of collimation on the appearance of relativistic jets (apparent velocity and Doppler factor). We argue that if the motion is relativistic, the high superluminal velocity are possible only if the geometrical collimation is smaller than the relativistic beaming angle γ−1. In the opposite case, the apparent image will be dominated by the part of the jet traveling directly towards the observer resulting in no apparent velocity. Furthermore, getting rid of the homokinetic hypothesis yields a complex relation between the observing angle and the Doppler factor, resulting in important consequences for the numerical computation of AGN population and unification scheme model.
The relation between the radio jet and the near-IR line emission in Seyfert galaxies
Authors: Riffel Rogemar A. , Storchi-Bergmann Thaisa
Published: February 2011

We used near-IR integral field spectroscopy, obtained with Gemini NIFS and GNIRS integral field units (IFUs), to map the ionized and molecular flux distributions and kinematics in the central few hundreds of parsecs of Seyfert galaxies. We conclude that the molecular gas emission can be considered a tracer of the feeding of the AGN, while the emission of the ionized gas a tracer of its feedback.
The Bardeen-Petterson effect as the precession mechanism for the radio galaxy 3C 84 (NGC 1275)
Authors: Teixeira D. M. , Abraham Z. , Caproni A. , Falceta-Gonçalves D.
Published: February 2011

In this work we propose the Bardeen-Petterson effect as the precession mechanism of the jet precession in NGC 1275. To check if this is true we have estimated the angular momentum ratio and the aligment timescale predict by the theory and compared with the numerical results presented in the literature. We were able to explain the precession period assuming an accretion disk with column surface density in the form of a power law with exponent 0.6 < s < 0.7 and a black hole rotation with a spin of 0.23 < a∗<0.4.
EVN monitoring observation of M 87 jet
Authors: Asada Keiichi , Nakamura Masanori , Doi Akihiro , Nagai Hiroshi , Inoue Makoto
Published: February 2011

We report results of our European VLBI Network observations towards M 87 jet at 1.6 GHz in order to study the velocity field. We revealed continuous jet up to 500 mas from the core and HST-1 component. We have not detected any proper motion for the components within first 160 mas from the core and significant superluminal motions from 2.5 to 3.5 c for the HST-1 components. Those are in good agreement with previous observations. We derived proper motions for the components about 160 to 500 mas from the core. Interestingly, the measured proper motions are faster than that of the inner components and slower than that of HST-1 components. It may suggest the possible acceleration region for superluminal features of M 87 jet.
Fitting along the Fundamental Plane: New comparisons of jet physics across the black hole mass scale
Authors: Markoff Sera , Nowak Michael A. , Maitra Dipankar , Wilms Jörn , Gallo Elena , Hynes Robert , Plotkin Richard
Published: February 2011

Correlations between the radio and X-ray bands in the hard state of black hole X-ray binaries (BHBs) have led to the discovery of the Fundamental Plane of black hole accretion, linking accretion-driven radiative attributes to black hole mass. Although this discovery has led to new constraints on radiative efficiencies, there is still significant degeneracy in terms of understanding the governing physics. I present several new results exploring the processes driving the Fundamental Plane over the black hole mass range. These include the first ever homogeneous fits of sources at approximately the same Eddington luminosity but millions of times different in mass, which I focus on for this proceeding article.
GRS 1915+105 “celebrates its majority” (1992–2010)
Authors: Castro-Tirado Alberto J.
Published: February 2011

Over the 18 years since its discovery, GRS 1915+105 has continuously brightened in the X/γ-ray sky. It is considered the prototypical microquasar. Most of these are LMXBs that show sporadic ejection of matter at apparently superluminal velocities. In these the three basic ingredients of quasars are found: a black hole, an accretion disc and collimated jets of high energy particles, but in microquasars the black hole is only a few M⊙ instead of several × 106 M⊙; the accretion disc had mean thermal temperature of several × 106 K instead of several × 103 K, and the particles ejected at relativistic speeds travel distances of a few ly only, compared to few × 106 ly as in radio galaxies. However many open issues remain to be addressed.
Do cataclysmic variables produce jets?
Authors: Tovmassian G. , Gänsicke B. , Zharikov S. , Ramirez A. , Diaz M.
Published: February 2011

It is believed that CVs do not produce jets unlike other, more massive interactive binaries. Here we present spectrophotometric observations of the super-outburst of V455 And. We show here that a strong wind perpendicular the the accretion disc at the maximum of the super-otburst, i.e a jet, can probably explain the observed spectroscopic behavior of this system.
The determination of the GX 339-4's mass based on its 2010 outburst
Authors: Chen Tao
Published: February 2011

In this paper we investigate the quasi periodic oscillation (QPO) behavior of the black hole candidate GX 339-4 during its 2010 outburst using RXTE/PCA data. We perform spectral and timing analysis of the observations, where the QPOs are observed. We analyze the relationship between the centroid frequency of QPO and the spectral parameters. The correlation of spectral and timing properties can be used to estimate the mass of black hole with the scaling method. Using this method we estimate a mass of 7.5 ± 0.8 M⊙ of GX 339-4.
On the apparent lack of Be X-ray binaries with black holes in the galaxy and in the Magellanic Clouds
Authors: Ziółkowski Janusz , Belczyński Krzysztof
Published: February 2011

In the Galaxy there are 67 Be X-ray binaries known to-date. Out of those, 45 host a neutron star, and for the reminder the nature of a companion is not known. None, so far, is known to host a black hole. This disparity is referred to as a missing Be – black hole X-ray binary problem. The stellar population synthesis calculations following the formation of Be X-ray binaries (Belczyński & Ziółkowski 2009) predict that the ratio of the binaries with neutron stars to the ones with black holes is rather high FNS/BH ~ 30–50. A comparison of this ratio with the number of confirmed Be – neutron star X-ray binaries (45) indicates that the expected number of Be – black hole X-ray binaries is of the order of only ~0–2. This is entirely consistent with the observed Galactic sample. Therefore, there is no problem of the missing Be+BH X-Ray Binaries for the Galaxy

In the Magellanic Clouds there are 94 Be X-ray binaries known to-date. Out of those, 60 host a neutron star. Again, none hosts a black hole. The stellar population synthesis calculations carried out specifically for the Magellanic Clouds (Ziółkowski & Belczyński 2010) predict that the ratio of the Be X-ray binaries with neutron stars to the ones with black holes is only FNS/BH ~ 10. This value is rather too low, as it implies the expected number of Be+BH X-ray binaries of the order of ~6, while none is observed. We found, that to remove the discrepancy, one has to take into account a different history of the star formation rate in the Magellanic Clouds, with the respect to the Galaxy. New stellar population synthesis calculations are currently being carried out.
Non thermal emission from T Tauri stars
Authors: del Valle María V. , Romero Gustavo E.
Published: February 2011

T Tauri stars are low mass, pre-main sequence stars. These objects are surrounded by an accretion disk and present strong magnetic activity. T Tauri stars are copious emitters of X-ray emission which belong to powerful magnetic reconnection events. Strong magnetospheric shocks are likely outcome of massive reconnection. Such shocks can accelerate particles up to relativistic energies through Fermi mechanism. We present a model for the high-energy radiation produced in the environment of T Tauri stars. We aim at determining whether this emission is detectable. If so, the T Tauri stars should be very nearby.
Exploring the association of Fermi sources with Young Stellar Objects
Authors: Munar-Adrover P. , Paredes J. M. , Romero G. E.
Published: February 2011

Massive protostars have associated bipolar outflows which can produce strong shocks when interact with the surrounding medium. Some theoretical models predict that particle acceleration at relativistic velocities can occur leading to gamma ray emission. In order to identify young stellar objects (YSO) that might emit gamma rays, we have crossed the Fermi First Year Catalog with catalogs of known YSOs, obtaining a set of candidates by spatial correlation. We have conducted Montecarlo simulations to find the probability of chance coincidence. Our results indicate that ~70% of the candidates should be gamma-ray sources with a confidence of ~5σ.
What is shaping the planetary nebula K3-35?
Authors: Gómez Y. , Tafoya D. , Anglada G. , Miranda L. F. , Uscanga L. , Torrelles J. M. , Velázquez P. F.
Published: February 2011

K 3-35 is a very young planetary nebula (PN) with a characteristic S-shaped radio emission morphology. It is the first PN where water vapor maser was detected: the emission is located in a torus-like structure with a radius of 100 AU and also at the surprisingly large distance of 5000 AU from the star, in the tips of the bipolar lobes. Several mechanism have been proposed to explain the bipolar morphology of PNe, and in the case of K 3-35 we believe we may be observing several of them at the same time: i) a disk-like structure traced by the H2O masers, ii) a precessing bipolar jet probably due to the presence of a binary companion and iii) circular polarization in the OH 1665 MHz masers, which suggests the presence of a magnetic field. Additional observations and modeling are needed to establish what mechanisms are shaping K 3-35.
The characteristics and simulation of close leader/return stroke field change waveforms
Authors: Zhang Qilin , Liu Xiaodong , Yang Jing , Jiang Rubin , Wang Zhenhui , Bian Jianchun
Published: February 2011

In order to reproduce the V‐shape structure characteristics of the close dart leader/return stroke field change, we employ two existing models, one for the “source charge” leader model and the other for MTLL return stroke model, both based on the assumption of uniform leader charge distribution along the channel and the charges deposited by the dart leader are completely neutralized by the following return stroke process. The simulated results show that the return stroke electric field is inversely related with the return stroke speed at early times (within few tens of microseconds of the beginning of the return stroke), while at later times (after 100 μs or so) the field is dominated by the deposited charge density component, the close electric field is independent of speed and the ratio of the leader field to the corresponding return stroke field tends to be equal to −1. Therefore, at early times (within few tens of microseconds) there is often some uncertainty regarding whether the charges deposited by the dart leader are completely neutralized by the following return stroke process based on the difference between the return stroke and the leader field on the ground. However, although several other return strokes models (TL, MTLE, TCS, BG and DU) exist, the results shown in the paper are strictly valid only for the used MTLL model.
Intraspecific genotypic richness and relatedness predict the invasibility of microbial communities
Authors: Jousset Alexandre , Schulz Wiebke , Scheu Stefan , Eisenhauer Nico
Published: February 2011

Biological invasions can lead to extinction events in resident communities and compromise ecosystem functioning. We tested the effect of two widespread biodiversity measurements, genotypic richness and genotypic dissimilarity on community invasibility. We manipulated the genetic structure of bacterial communities (Pseudomonas fluorescens) and submitted them to invasion by Serratia liquefaciens. We show that the two diversity measures impact on invasibility via distinct and additive mechanisms. Genotypic dissimilarity of the resident communities linearly increased productivity and in parallel decreased invasion success, indicating that high dissimilarity prevents invasion through niche pre-emption. By contrast, genotypic richness exerted a hump-shaped effect on invasion and was linked to the production of toxins antagonistic to the invader. This effect peaked at intermediate richness, suggesting that high richness levels may increase invasibility. Invasibility could be well predicted by the combination of these two mechanisms, documenting that both genotypic richness and dissimilarity need to be considered, if we are to understand the biotic properties determining the susceptibility of ecosystems to biological invasions.
Enhanced Striatal Dopamine Release During Food Stimulation in Binge Eating Disorder
Authors: Wang Gene‐Jack , Geliebter Allan , Volkow Nora D. , Telang Frank W. , Logan Jean , Jayne Millard C. , Galanti Kochavi , Selig Peter A. , Han Hao , Zhu Wei , Wong Christopher T. , Fowler Joanna S.
Published: February 2011

Subjects with binge eating disorder (BED) regularly consume large amounts of food in short time periods. The neurobiology of BED is poorly understood. Brain dopamine, which regulates motivation for food intake, is likely to be involved. We assessed the involvement of brain dopamine in the motivation for food consumption in binge eaters. Positron emission tomography (PET) scans with [11C]raclopride were done in 10 obese BED and 8 obese subjects without BED. Changes in extracellular dopamine in the striatum in response to food stimulation in food‐deprived subjects were evaluated after placebo and after oral methylphenidate (MPH), a drug that blocks the dopamine reuptake transporter and thus amplifies dopamine signals. Neither the neutral stimuli (with or without MPH) nor the food stimuli when given with placebo increased extracellular dopamine. The food stimuli when given with MPH significantly increased dopamine in the caudate and putamen in the binge eaters but not in the nonbinge eaters. Dopamine increases in the caudate were significantly correlated with the binge eating scores but not with BMI. These results identify dopamine neurotransmission in the caudate as being of relevance to the neurobiology of BED. The lack of correlation between BMI and dopamine changes suggests that dopamine release per se does not predict BMI within a group of obese individuals but that it predicts binge eating.
Decreased Serum Creatinine Concentration Is Associated With Short Telomeres of Adipose Tissue Cells
Authors: Fernández‐Real J.M. , Moreno‐Navarrete J.M. , Ortega F. , Ricart W.
Published: February 2011

Decreased serum creatinine concentration has been recently described to constitute a new risk factor of type 2 diabetes. Increased free radicals have been consistently associated with decreased serum creatinine and with cellular senescence. Telomere length is considered as a biological marker for senescence. We aimed to study the association of telomere length with serum creatinine. Telomere length of subcutaneous adipose tissue cells was measured in a sample of obese and nonobese subjects (n = 49). Telomere length of subcutaneous adipose tissue cells was positively associated with serum creatinine (r = 0.40, P = 0.004), i.e., the lower the telomere length, the lower the serum creatinine, but not with glomerular filtration rate (GFR). In addition, telomere length was negatively associated with BMI (r = −0.45, P = 0.001) and systolic blood pressure (r = −0.41, P = 0.003). In a multiple linear regression analysis, BMI (P = 0.005), systolic blood pressure (P = 0.01) and telomere length (P = 0.03) independently contributed to 37% of serum creatinine variance after controlling for sex and age. In conclusion, the association of serum creatinine with a marker of cellular senescence suggests an underlying mechanism influencing both decreased serum creatinine and increased risk of type 2 diabetes.
Pulsed electron–electron double resonance: beyond nanometre distance measurements on biomacromolecules
Authors: Reginsson Gunnar W. , Schiemann Olav
Published: February 2011

PELDOR (or DEER; pulsed electron–electron double resonance) is an EPR (electron paramagnetic resonance) method that measures via the dipolar electron–electron coupling distances in the nanometre range, currently 1.5–8 nm, with high precision and reliability. Depending on the quality of the data, the error can be as small as 0.1 nm. Beyond mere mean distances, PELDOR yields distance distributions, which provide access to conformational distributions and dynamics. It can also be used to count the number of monomers in a complex and allows determination of the orientations of spin centres with respect to each other. If, in addition to the dipolar through-space coupling, a through-bond exchange coupling mechanism contributes to the overall coupling both mechanisms can be separated and quantified. Over the last 10 years PELDOR has emerged as a powerful new biophysical method without size restriction to the biomolecule to be studied, and has been applied to a large variety of nucleic acids as well as proteins and protein complexes in solution or within membranes. Small nitroxide spin labels, paramagnetic metal ions, amino acid radicals or intrinsic clusters and cofactor radicals have been used as spin centres.
A reversible time-of-flight detector for use in pseudocontinuous resonance enhanced multiphoton (pc-REMPI) detection
Authors: McRaven C. P. , Shafer-Ray N. E.
Published: February 2011

A time-of-flight coincidence detector is demonstrated. This detector is optimized for use in a pseudocontinuous resonance enhanced multiphoton ionization scheme that requires photoelectrons and photoions to be detected in coincidence. The detector utilizes two simultaneously operating charged particle detectors, one for the detection of electrons and the other for the detection of ions. In order to allow for field reversal, the detectors are physically identical, differing only by the value of applied voltages. Particular attention is given to the implementation of a charge-to-voltage transducer that allows for subnanosecond detection of both electrons and ions.