bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential effects of hydrogen peroxide and ascorbic acid on the aerobic thermosensitivity of yeast cells grown under aerobic and anoxic conditions
Authors: Moraitis Christos , Curran Brendan P. G.
Published: December 2009

We have previously demonstrated that in aerobically‐grown cells of the yeast Saccharomyces cerevisiae, hydrogen peroxide (H2O2) increases and ascorbic acid decreases cellular thermosensitivity, as determined by the inducibility of a heat shock (HS)‐reporter gene. In this work, we reveal that the aerobic thermosensitivity of anaerobically‐grown yeast cells also increases in the presence of H2O2, albeit differentially between cells with two different lipid profiles. In comparison to aerobically‐grown fermenting cells treated with the same H2O2 concentration, both these types of anaerobically‐grown cells were found to be considerably less sensitive to aerobic heat shock and considerably more thermotolerant. Paradoxically, and in contrast to ascorbate‐pretreated aerobically‐grown yeast cells, when anaerobically‐grown cells were heat‐shocked aerobically in the presence of the same ascorbic acid concentration, they exhibited increased thermosensitivity and decreased intrinsic thermotolerance with respect to their untreated counterparts. These findings are discussed with respect to what is currently known about the redox and physiological status of yeast cells grown aerobically and cells reoxygenated following anoxic growth. Copyright © 2009 John Wiley & Sons, Ltd.
Bioavailability of procyanidin dimers and trimers and matrix food effects in in vitro and in vivo models
Authors: Serra Aida , Macià Alba , Romero Maria-Paz , Valls Josep , Bladé Cinta , Arola Lluís , Motilva Maria-José
Published: December 2009

Among procyanidins (PC), monomers, such as catechin and epicatechin, have been widely studied, whereas dimer and trimer oligomers have received much less attention, despite their abundance in our diet. Recent studies have showed that as dimers and trimers could be important in determining the biological effects of procyanidin-rich food, understanding their bioavailability and metabolism is fundamental. The purpose of the present work is to study the stability of PC under digestion conditions, the metabolism and the bioavailability by using a combination of in vitro and in vivo models. Simultaneously, the matrix effect of a carbohydrate-rich food on the digestibility and bioavailability of PC is investigated. The results show a high level of stability of PC under gastric and duodenal digestion conditions. However, the pharmacokinetic study revealed limited absorption. Free forms of dimers and trimers have been detected in rat plasma, reaching the maximum concentration 1 h after oral intake of a grape seed extract.
What Determines the Length of a Typical Canadian Parliamentary Government?
Authors: Ferris J. Stephen , Voia Marcel-Cristian
Published: December 2009

Abstract.In this paper we examine the length of political tenure in Canadian federally elected parliamentary governments since 1867. Using annual data on tenure length, we categorize the distribution of governing tenures in terms of a hazard function: the probability that an election will arise in each year, given that an election has not yet been called. Structuring the election call as an optimal stopping rule, we test whether that distribution responds predictably to characteristics of the political and/or economic environment. The results of using the continuous Cox and Gompertz models together with the discrete semi-parametric proportional hazard model suggest that governing parties in Canada do engage in election timing and that the only economic policy measure that is used consistently in conjunction with election timing is fiscal expenditure.

Résumé.Dans cet ouvrage, nous examinons la durée d'un régime parlementaire canadien depuis la Confédération de 1867. Nous utilisons des données annuelles et nous représentons la distribution de durée de vie d'un gouvernement par une fonction de hazard, c'est-a-dire, la probabilité qu'une élection soit déclenchée durant une année spécifique étant donné qu'elle ne l'a pas encore été jusqu'à présent. Nous modélisons un déclenchement d'élection par une règle d'arrêt optimal el nous testons si la distribution dépend des caractéristiques de l'environnement politique et économique tel que prédit selon la théorie. Nous résultats basés les modèles de hazard proportionnel continu de type Cox et Gompertz et discret semi-paramétrique révèlent que les partis fédéraux au pouvoir au Canada choisissent le moment opportun pour déclencher une élection. De plus, les dépenses fiscales sont la seule variable de politique économique qui y soit systématiquement relié.
Disability Rights Activists in the Supreme Court of Canada: Legal Mobilization Theory and Accommodating Social Movements
Authors: Vanhala Lisa
Published: December 2009

Abstract.Disability rights organizations have been active participants before the Supreme Court of Canada (SCC) since the mid-1980s but they have been completely neglected in the literature on social movement legal mobilization. This paper seeks to remedy this lacuna by providing an overview of the litigation activity of the main disability rights organizations. It builds on an emerging complementary theoretical perspective for understanding the participation by movement actors in the Court. Through an analysis of shared and contested collective meaning frames within and across social movement organizations we can complement existing theoretical explanations for the overall development of legal mobilization by social movement actors.

Résumé.Les organismes du mouvement de défense des droits des personnes handicapées prennent une part active aux litiges devant la Cour suprême du Canada depuis le milieu des années quatre-vingt. Toutefois, on ne retrouve pas trace de ce mouvement dans la littérature sur la mobilisation des acteurs collectifs dans les lieux juridiques. Le présent article vient combler cette lacune en analysant les activités du mouvement dans ce domaine. L'article s'appuie sur une perspective théorique novatrice et complémentaire qui s'intéresse particulièrement aux rôles que jouent les idées organisationnelles et les relations intra-organisationnelles (conflictuelles ou de coopération) au sein du mouvement. L'article met de l'avant une explication qui combine ces deux facteurs pour mieux expliquer les tendances activistes de participation aux litiges par rapport aux analyses «classiques» qui ne prennent en compte que les ressources ou le contexte politique.
The sensitivity of United Kingdom health-care services to the diverse needs of Chinese-origin older people
Authors: CHAU RUBY C. M. , YU SAM WAI-KAM
Published: December 2009

This paper is a contribution to the debate on how to make health-care services in the United Kingdom more responsive to the needs of older people who are members of recent immigrant groups. The focus is on the Chinese-origin elders, and the objective is to demonstrate their diverse migrant histories, cultural backgrounds and attitudes to both ‘traditional’ and Western health-care practices. The underlying argument is that if National Health Service staff had a better understanding of the diversity of Chinese older people, this would make an important contribution to making the service more sensitive to their needs. To develop this argument, this paper carries out three main analytical tasks. The first is to discuss the range of strategies adopted by Chinese people in general and Chinese older people in particular to improve their health. The second is to study Chinese people's heritage of exploring different methods to organise health in response to foreign culture. The third considers the ways in which the sensitivity of British health-care services to the needs of ethnic-minority groups can be improved, with a focus on the culturagram instrument and procedure. Three contrasting examples are presented.
How health affects retirement decisions: three pathways taken by middle-older aged New Zealanders
Authors: POND RACHAEL , STEPHENS CHRISTINE , ALPASS FIONA
Published: December 2009

Concerns about the economic impact of an ageing population have triggered many developed countries to advance policies that attempt to extend working lives and discourage early retirement. There is considerable evidence of a relationship between poor health and early retirement, but some researchers have suggested that there is a ‘justification bias’ in claims that ill-health is the cause of retirement. This paper reports a longitudinal qualitative study that interviewed 60 New Zealanders aged between 55 and 70 years on two occasions, and analysed their explanations of health-related retirement decisions. Although the participants' explanations included poor health as an important reason for retirement, two additional health-related retirement pathways were identified: the ‘maximisation of life’, being decisions to retire whilst healthy to fulfil other life goals; and ‘health protection’, being decisions motivated by health protection and promotion. These health pathways interacted with other factors such as financial security. An elucidation of these motivations pays particular attention to the social and discursive context of explanations of retirement, and considers the three identified health-retirement pathways in relation to the sickness justification bias and current government policies to extend working lives.
That's not my Robert! Identity maintenance and other warrants in family members' claims about mistreatment in old-age care
Authors: HARNETT TOVE , JÖNSON HÅKAN
Published: December 2009

This study has explored how family members of care recipients define and sustain claims of mistreatment in old-age care. Twenty-one informants were recruited from an association of relatives of care recipients in Sweden. Using argumentation analysis, four warrants about mistreatment were identified from the qualitative interview data: they referred to physical harm, psychological harm, social-care deficiencies and identity subversion. The first three categories are similar to those recognised in previous research on elder mistreatment, but the fourth, which is described in detail in the article, is less familiar: elder mistreatment as the violation of an older person's identity. The family members backed their claims about staff members' violation of a care recipient's persona or identity by using arguments that drew on their unique knowledge of the care recipient's appearance, daily routines and preferred activities. They also described their attempts to protect the dignity and identity of a care recipient, their fears of abuse, and actual cases of conflict and retribution by care staff. They consistently positioned themselves as guardians of identity through their claims of mistreatment. The study provides important knowledge about family members' moral view of elder mistreatment, which may enhance the understanding of conflicts between formal care providers and family members.
The effects of age on health problems that affect the capacity to work: an analysis of United Kingdom labour-force data
Authors: NUÑEZ IMANOL
Published: December 2009

This study estimates the effect of increases in age on 16 health problems that affect paid work for men and women in the United Kingdom. The analysis is based on a sample of the United Kingdom household population from the Office for National Statistics Labour Force Survey of 2007. Using multinomial logit regressions, the results reveal considerable diversity in the relationships between age and the reported prevalence of health problems that affect work. In particular, problems with heart, blood and circulation, arms and hands, legs and feet were strongly related to age, while difficulties in seeing and hearing, skin conditions and allergies appeared not to be more prevalent among older workers than younger employees. Regarding gender differences, it was found that, in general, women's health-related ability to participate in work was less affected by age, but that they suffered particular problems with arms and hands, skin conditions, allergies and depression. Finally, the study analyses the non-linear effects of unit increases in age. Such analysis may usefully identify the ages (or inflection points) at which ageing intensifies its effects on occupational health. These findings point to the importance of intervention at the appropriate time, when preventive measures may avoid the exacerbation of the health problem.
Cross-linguistic syntactic priming in bilingual children
Authors: VASILYEVA MARINA , WATERFALL HEIDI , GÁMEZ PERLA B. , GÓMEZ LIGIA E. , BOWERS EDMOND , SHIMPI PRIYA
Published: December 2009

Previous research has used cross-linguistic priming methodology with bilingual adults to explore the nature of their syntactic representations. The present paper extends the use of this methodology to bilingual children to investigate the relation between the syntactic structures of their two languages. Specifically, we examined whether the use of passives by the experimenter in one language primed the subsequent use of passives by the child in the other language. Results showed evidence of syntactic priming from Spanish to English: hearing a Spanish sentence containing a passive led to the increase in children's production of the parallel structure in English. However, there was no priming in the other direction: hearing an English sentence containing a passive did not increase children's use of the parallel structure in Spanish. These results provide evidence for both the integration of syntactic representations in bilingual children and the asymmetry of the relation between their two languages.
Quantity and significance of wild meat off-take by a rural community in the Eastern Cape, South Africa
Authors: KASCHULA SARAH A. , SHACKLETON CHARLIE M.
Published: December 2009

When compared to tropical forest zones in west and central Africa, off-take of wild meat from savannah and grassland biomes by local rural communities has not been well assessed. This case study of wild meat collection activities within a rural community in the Mount Frere region of the Eastern Cape (South Africa) uses last-catch records derived from 50 wild meat gatherers to calculate average off-take of taxa, species and fresh mass of wild meat per collection event. When per-event off take is overlaid onto household hunting frequency data, annual off-take would be 268.6 kg km−2yr−1or 3 kg person−1yr−1presuming constant off-take over an annual period. Monetary value of off-take would be South African R 307 (US$ 39) per household annually. For some species, off-take weight per km2shows similar values to data from tropical forest zones, but high human population densities tend to dilute off-takes to less nutritionally significant amounts at the per person scale. However, unlike many tropical zones, none of the species harvested can be considered high-priority conservation species. Even densely populated and heavily harvested communal lands appear to offer high wild meat off-takes from low conservation priority species.
Variation in the host ABO blood group may be associated with susceptibility to hepatitis C virus infection
Authors: BEHAL R. , JAIN R. , BEHAL K. K. , DHOLE T. N.
Published: December 2009

This study aimed to determine the relationship between hepatitis C virus (HCV) infection and ABO/Rhesus blood groups, age and sex. A total of 20 000 patients who came to donate blood in the blood bank of GSVM Medical College, Kanpur were enrolled in the study. Demographic data recorded for each patient included age, sex and blood group. Blood samples were tested for anti-HCV antibodies and ABO/Rhesus blood group antigen typing was performed. The overall positive rate of anti-HCV was 0·34%. We found that seropositivity for HCV increased with age. Anti-HCV antibodies were detected in 1/765 women (0·13%), compared to 67/19 235 men (0·35%). Seroprevalence of HCV was found to be higher in blood group O individuals (0·42%) and lowest in blood group AB individuals (0·04%). The results of this study demonstrate that that HCV infection may not be related to age and sex but the possible association of blood group antigens with HCV infection cannot be ruled out.
Molecular characterization of SAT 2 foot-and-mouth disease virus from post-outbreak slaughtered animals: implications for disease control in Uganda
Authors: BALINDA S. N. , BELSHAM G. J. , MASEMBE C. , SANGULA A. K. , SIEGISMUND H. R. , MUWANIKA V. B.
Published: December 2009

In Uganda, limiting the extent of foot-and-mouth disease (FMD) spread during outbreaks involves short-term measures such as ring vaccination and restrictions of the movement of livestock and their products to and from the affected areas. In this study, the presence of FMD virus RNA was investigated in cattle samples 3 months after FMD quarantine measures had been lifted following an outbreak in 2004. Oropharyngeal tissue samples were obtained from 12 cattle slaughtered in a small town abattoir in Kiboga. FMD virus RNA was detected by diagnostic RT–PCR in nine of the 12 tissue samples. Part of the coding region for the capsid protein VP1 was amplified and sequenced. All samples were identified as belonging to the SAT 2 serotype. The implications for FMD control of both virus introduction into Uganda and the presence of carrier animals following outbreaks are discussed.
Long-range migration of a chinstrap penguin from Bouvetøya to Montagu Island, South Sandwich Islands
Authors: Biuw Martin , Lydersen Christian , Nico de Bruyn P.J. , Arriola Aline , Hofmeyr Greg G.J. , Kritzinger Petrus , Kovacs Kit M.
Published: December 2009

We describe a long-range migration of a pre-moulting adult chinstrap penguin from Bouvetøya, a small relatively recently established colony, to the South Sandwich Islands, where large, established colonies of this species reside. The trip lasted around three weeks, covered ∼3600 km, and the time of arrival was consistent with the annual moult. The bird did not travel along the shortest path or along a constant bearing, but instead followed what appeared to be a series of two or three rhumb lines of constant bearing. Small southward and northward deviations from the general path were consistent with local water currents. Travel speeds were high during daylight but decreased at night, suggesting that resting or opportunistic feeding occurred preferentially at night. While long-range winter migrations of chinstraps to feeding areas in the vicinity of distant colonies have been previously described, this is the first observation of such a trip during the period between breeding and moulting, and the first record of an individual actually arriving at one of these distant colonies. This has implications for understanding population structure and management of this important Southern Ocean predator.
North American population estimates of waterbirds, vultures and hawks from migration counts in Veracruz, México
Authors: INZUNZA ERNESTO RUELAS , GOODRICH LAURIE J. , HOFFMAN STEPHEN W.
Published: December 2009

Continental-scale bird population estimates are used as a decision-support tool in conservation plans. The calculation of these estimates includes the use of density values and survey data from one or multiple sources extrapolated to the geographic scale of interest. In this paper, we use migration count data from a migration monitoring project in Veracruz, Mexico, to revise existing North American population estimates of seven species of waterbirds, New World vultures, and diurnal raptors. In two species of waterbirds, we suggest that existing estimates are low and propose a mechanism to correct these figures. In the remaining five cases, we also determine present estimates are low, but use our data to provide new continental-scale values. We discuss the importance of refining population estimates using data from a diverse suite of field methods as a means to overcome the limitations of the single-survey-based estimates.
Metaphysical (Im)mortality and Philosophical Transcendence
Authors: Haldane John
Published: December 2009

There is a lapidary saying owing to Etienne Gilson, that is often misquoted or adapted – with ‘metaphysics’ taking the place of ‘philosophy’ – and which is invariably reproduced in isolation. It is that ‘Philosophy always buries its undertakers’. Understanding this remark as Gilson intended it is relevant to the issues of the nature of philosophy, and of what conception of it may be most appropriate or fruitful for us to pursue. The question of the mortality or otherwise of philosophy in general, and of metaphysics in particular, is a significant one for ongoing intellectual enquiry, and it is also relevant to the current position of academic philosophy in Great Britain and in the English-speaking world.
Can Philosophy be a Rigorous Science?
Authors: Philipse Herman
Published: December 2009

It is difficult to imagine that a Royal Institute of Physics would organize an annual lecture series on the theme ‘conceptions of physics’. Similarly, it is quite improbable that a Royal Institute of Astronomy would even contemplate inviting speakers for a lecture series called ‘conceptions of astronomy’. What, then, is so special about philosophy that the theme of this lecture series does not appear to be altogether outlandish? Is it, perhaps, that philosophy is the reflective discipline par excellence, so that the very nature of philosophy is a topic that belongs to its domain of investigations? Or is there something more serious at issue? Let me first tell you how the question concerning the nature of philosophy arose for me as a young student, and how I tried to answer it, quite naively, by endorsing Edmund Husserl's programme of turning philosophy into a rigorous science. In a second section, I shall offer three diagnoses of the fact that all such attempts seem to have failed. Finally, I'd like to say a few words on my own research agenda in philosophy and on a public function of philosophers.
Plotinus: Charms and Countercharms
Authors: Clark Stephen R. L.
Published: December 2009

For the last few years, thanks to the Leverhulme Trust, I've been largely absent from my department, working on the late antique philosopher Plotinus. To speak personally – it's been a difficult few years, since my youngest daughter has been afflicted with anorexia during this period, and my own bowel cancer was discovered, serendipitously, and removed, at the end of 2005. Since then I've had ample occasion to consider the importance – and the difficulty – of the practice of detachment, and also to worry about the moral some have drawn from Plotinian and similar philosophies, namely that the things of this world really do not matter much, and that we should withdraw ourselves from them. Maybe it is true, as Plotinus says, that ‘some troubles are profitable to the sufferers themselves, poverty and sickness for example’. But this is not an altogether helpful message for those afflicted by the bundle of disorders that lead to anorexia. It's difficult not to suspect, for example, that Simone Weil would have lived longer but for her Neo-Platonism. It has also been made obvious to me that we are (or at any rate, I am) much less in control of our own mental and emotional states even than I had thought before. None of this, of course, should have been any surprise: I have frequently pointed out – to myself and others – the importance of distinguishing between one's self and the states one finds oneself in, and the extreme difficulty of controlling the thoughts we say are ours (but which, by that very fact, reveal themselves as very far from ours). Any delusion that my knowledge of these facts is of itself enough to render me immune to them has been – at least for the moment – thoroughly debunked – though the facts themselves are such that this disillusionment, so to call it, is probably both temporary and almost entirely insincere!
What is Humane Philosophy and Why is it At Risk?
Authors: Cottingham John
Published: December 2009

Let me begin with what may seem a very minor point, but one which I think reveals something about how many philosophers today conceive of their subject. During the past few decades, there has been an increasing tendency for references in philosophy books and articles to be formatted in the ‘author and date’ style (‘see Fodor (1996)’, ‘see Smith (2001)’.) A neat and economical reference system, you may think; and it certainly saves space, albeit inconveniencing readers by forcing them to flip back to the end of the chapter or book to find the title of the work being referred to. But what has made this system so popular among philosophers? A factor which I suspect exerts a strong subconscious attraction for many people is that it makes a philosophy article look very like a piece of scientific research. For if one asks where the ‘author-date’ system originated, the answer is clear: it comes from the science journals. And in that context, the choice of referencing system has a very definite rationale. In the progress-driven world of science, priority is everything, and it's vitally important for a career that a researcher is able to proclaim his work as breaking new ground. Bloggs (2005) developed a technique for cloning a certain virus; Coggs (2006) showed how certain bits of viral DNA could be spliced; and now Dobbs (2007) draws on both techniques to develop the building blocks of a new vaccine. The idea is that our knowledge-base is enhanced, month by month and year by year, in small incremental steps (perhaps with occasional major breakthroughs); and in the catalogue of advances, the date tagged to each name signals when progress was made, and by whom.
A NOTE ON TARIFF POLICY, INCREASING RETURNS, AND ENDOGENOUS FLUCTUATIONS
Authors: Chen Yan , Zhang Yan
Published: December 2009

We show that the introduction of a constant tariff or subsidy levied on foreign energy can lead to a rich set of endogenous fluctuations around the unique steady state, including stable 2-, 4-, 8-, and 15-cycles, quasiperiodic orbits, and chaos. This is demonstrated in a standard neoclassical growth model with social increasing returns to scale. Numerical exercises could be viewed from a methodological perspective as illustrating that capital income taxes and tariffs are equivalent in generating endogenous fluctuations because Guo and Lansing [Guo, J.T. and K.J. Lansing (2002) Fiscal policy, increasing returns and endogenous fluctuations. Macroeconomic Dynamics 6, 633–664] show that a constant capital tax or subsidy has the same effect on the model dynamics in a one-sector closed economy.
Dairy consumption and circulating levels of inflammatory markers among Iranian women
Authors: Esmaillzadeh Ahmad , Azadbakht Leila
Published: December 2009

Objective

Although recent studies have shown an inverse relationship between dairy consumption and metabolic abnormalities, we are aware of no study evaluating the association between dairy consumption and circulating levels of inflammatory markers. The current study was undertaken to assess the association between the consumption of high-fat and low-fat dairy products and circulating levels of inflammatory markers among Tehrani women aged 40–60 years.

Design

In a cross-sectional study of 486 apparently healthy women aged 40–60 years, we assessed usual dietary intakes by means of an FFQ. Anthropometric measurements were made and fasting blood samples were taken for measuring inflammatory markers.

Results

The reported mean (sd) daily intake of low- and high-fat dairy consumption was 85 (sd 23) and 101 (sd 29) g/d, respectively. After control for age, BMI, waist circumference and other potential confounders, low-fat dairy consumption was inversely associated with C-reactive protein (β = −0.04), IL-6 (β = −0.02) and soluble vascular cell adhesion molecule-1 (β = −0.06); with further adjustment for dietary intakes, the associations remained significant just for soluble vascular cell adhesion molecule-1 (β = −0.03). High-fat dairy intake was positively associated with log-transformed values of serum amyloid A (β = 0.08) and soluble vascular cell adhesion molecule-1 (β = 0.05), both before and after adjustment for all potential confounding variables. No overall significant associations were found between total dairy consumption and inflammation.

Conclusions

The current study indicates an independent relationship between high-fat as well as low-fat dairy consumption, not total dairy intake, and some markers of inflammation and endothelial dysfunction. Further studies are required to identify responsible components of dairy products and related mechanisms of action.
REES MATRIX CONSTRUCTIONS FOR CLUSTERING OF DATA
Authors: KELAREV A. V. , WATTERS P. , YEARWOOD J. L.
Published: December 2009

This paper continues the investigation of semigroup constructions motivated by applications in data mining. We give a complete description of the error-correcting capabilities of a large family of clusterers based on Rees matrix semigroups well known in semigroup theory. This result strengthens and complements previous formulas recently obtained in the literature. Examples show that our theorems do not generalize to other classes of semigroups.
Bovine respiratory disease research (1983–2009)
Authors: Fulton Robert W.
Published: December 2009

Bovine respiratory disease (BRD) research has provided significant understanding of the disease over the past 26 years. Modern research tools that have been used include monoclonal antibodies, genomics, polymerase chain reaction, immunohistochemistry (IHC), DNA vaccines and viral vectors coding for immunogens. Emerging/reemerging viruses and new antigenic strains of viruses and bacteria have been identified. Methods of detection and the role for cattle persistently infected bovine viral diarrhea virus (BVDV) were identified; viral subunits, cellular components and bacterial products have been characterized. Product advances have included vaccines for bovine respiratory syncytial virus,Mannheimia haemolyticaandPasteurella multocida; the addition of BVDV2 to the existing vaccines and new antibiotics. The role ofMycoplasmaspp., particularlyMycoplasma bovisin BRD, has been more extensively studied. Bovine immunology research has provided more specific information on immune responses, T cell subsets and cytokines. The molecular and genetic basis for viral–bacterial synergy in BRD has been described. Attempts have been made to document how prevention of BRD by proper vaccination and management prior to exposure to infectious agents can minimize disease and serve as economic incentives for certified health programs.
Growth of microorganisms in Martian-like shallow subsurface conditions: laboratory modelling
Authors: Pavlov A.K. , Shelegedin V.N. , Vdovina M.A. , Pavlov A.A.
Published: December 2009

Low atmospheric pressures on Mars and the lack of substantial amounts of liquid water were suggested to be among the major limiting factors for the potential Martian biosphere. However, large amounts of ice were detected in the relatively shallow subsurface layers of Mars by the Odyssey Mission and when ice sublimates the water vapour can diffuse through the porous surface layer of the soil. Here we studied the possibility for the active growth of microorganisms in such a vapour diffusion layer. Our results showed the possibility of metabolism and the reproduction of non-extremophile terrestrial microorganisms (Vibrio sp.) under very low (0.01–0.1 mbar) atmospheric pressures in a Martian-like shallow subsurface regolith.
Investigation of Li/Ca variations in aragonitic shells of the ocean quahog Arctica islandica, northeast Iceland
Authors: Thébault Julien , Schöne Bernd R. , Hallmann Nadine , Barth Matthias , Nunn Elizabeth V.
Published: December 2009

Interannual and intra‐annual variations in lithium‐to‐calcium ratio were investigated with high temporal resolution in the aragonitic outer shell layer of juvenile Arctica islandica (Mollusca; Bivalvia) collected alive in 2006 off northeast Iceland. Li/Cashell ranged between 7.00 and 11.12 μmol mol−1 and presented well‐marked seasonal cycles with minimum values recorded at the annual growth lines; a general pattern was a progressive increase in Li/Cashell from March to May, followed by a plateau in June and a decrease down to minimum values in July–August. Li/Cashell was correlated with δ18Oshell‐derived temperature, but the strength of this relationship was weak (r2 < 0.25 and p < 0.05). It covaried significantly with microgrowth increment width and with the discharge from one of the closest rivers. Seasonal variations of Li/Cashell in A. islandica may most likely be explained (1) by calcification rate and/or (2) by significant river inputs of Li‐rich silicate particles flowing to the sea as soon as snow melts. In the first case, Li/Cashell may be a useful proxy for addressing seasonal variations of growth rate in bivalves that lack discernable microgrowth patterns. Abrupt decreases of Li/Cashell may, in turn, help identify growth retardations due to harsh environmental conditions. Alternatively, if Li/Cashell variations are linked to particulate Li inputs by rivers, this could be a new proxy for the intensity of mechanical weathering of Icelandic basalts, with interesting perspectives for the reconstruction of frequency and intensity of past jökulhlaups (subglacial outburst floods). Further works, including experimental studies, are needed to test these hypotheses.
Uplift histories from river profiles
Authors: Pritchard D. , Roberts G. G. , White N. J. , Richardson C. N.
Published: December 2009

Longitudinal river profiles, where elevation of a river bed is plotted as a function of distance along the river bed, contain information about uplift rate. When a region adjacent to a reference level (e.g., sea level) is uplifted, a rapid change in gradient occurs near the river mouth. The erosional process causes this change in gradient to migrate upstream. Thus a river profile is effectively a ‘tape recording’ of the uplift rate history, provided that the erosional process can be adequately parameterized. Here, we use a non‐linear equation to relate the shape of a river profile, z(x), to uplift rate history, U(t). If erosion is assumed to be dominated by knickpoint retreat, an inverse model can be formulated and used to calculate uplift rate histories. Our model builds upon standard stream profile analysis, which focuses on the relationship between profile slope and drainage area. We have applied this analytical approach to river profiles from the Bié Dome, Angola. Calculated uplift rate histories agree with independent geologic estimates.
A possible explanation for difference in stress drop between intraplate and interplate earthquakes
Authors: Kato Naoyuki
Published: December 2009

It is known from observations that stress drop of intraplate earthquakes is larger than that of interplate earthquakes on average. I present a mechanical model for explaining the difference in stress drop, where an intraplate fault is assumed to be loaded uniformly, while a locked area (an asperity) on a plate boundary is nonuniformly loaded by surrounding aseismic sliding. A numerical simulation is conducted to quantitatively evaluate the difference in stress drop for different loading processes. Because the model intraplate fault is uniformly loaded, stress drop is uniform over the fault with a larger average value. In contrast, stress concentration is generated at a boundary region between locked area and aseismic sliding area for a model interplate earthquake. This stress concentration hastens earthquake occurrence, resulting in lower average stress drop. The stress drop of simulated intraplate earthquakes is several tens percent larger than that of simulated interplate earthquakes.
Freshwater fluxes in the East Greenland Current: A decade of observations
Authors: de Steur L. , Hansen E. , Gerdes R. , Karcher M. , Fahrbach E. , Holfort J.
Published: December 2009

Over a decade of mooring measurements in the western Fram Strait at 78°50′N shows that the annual mean liquid freshwater flux (FWF) in the East Greenland Current is relatively constant at −1274 ± 453 km3 yr−1 (−40.4 ± 14.4 mSv) despite the fact that the annual mean total volume transport of the EGC has more than doubled since 2001. This is shown to be due to an increase of the transport in the deeper ocean and the fact that the largest FW content is present on the East Greenland shelf and not in the core of the EGC. In order to capture the FWF on the shelf modeling results of NAOSIM are included showing that a mean contribution of FWF on the shelf of at least −807 ± 357 km3 yr−1 (−25.6 ± 11.3 mSv) should be added to the FWF obtained for the EGC. When compared to the extra input of freshwater required to account for the 1960–1990 freshening of the northern North Atlantic, the observed variations in the 1998–2008 EGC liquid freshwater fluxes are small.
Infrasonic signature of the 2009 major sudden stratospheric warming
Authors: Evers L. G. , Siegmund P.
Published: December 2009

The study of infrasound is experiencing a renaissance since it was chosen as a verification technique for the Comprehensive Nuclear‐Test‐Ban Treaty. The success of the verification technique strongly depends on knowledge of upper atmospheric processes. The ability of infrasound to probe the upper atmosphere starts to be exploited, taking the field beyond its monitoring application. Processes in the stratosphere couple to the troposphere and influence our daily weather and climate. Infrasound delivers actual observations on the state of the stratosphere with a high spatial and temporal resolution. Here we show the infrasonic signature, passively obtained, of a drastic change in the stratosphere due to the major sudden stratospheric warming (SSW) of January 2009. With this study, we infer the enormous capacity of infrasound in acoustic remote sensing of stratospheric processes on a global scale with surface based instruments.
Large‐scale simulation of methane hydrate dissociation along the West Spitsbergen Margin
Authors: Reagan Matthew T. , Moridis George J.
Published: December 2009

Vast quantities of methane are trapped in oceanic hydrate deposits, and there is concern that a rise in the ocean temperature will induce dissociation of these hydrate accumulations, potentially releasing large amounts of methane into the atmosphere. The recent discovery of active methane gas venting along the landward limit of the gas hydrate stability zone (GHSZ) on the shallow continental slope west of Spitsbergen could be an indication of this process, if the source of the methane can be confidently attributed to dissociating hydrates. In the first large‐scale simulation study of its kind, we simulate shallow hydrate dissociation in conditions representative of the West Spitsbergen margin to test the hypothesis that the observed gas release originated from hydrates. The simulation results are consistent with this hypothesis, and are in remarkable agreement with the recently published observations. They show that shallow, low‐saturation hydrate deposits, when subjected to temperature increases at the seafloor, can release significant quantities of methane, and that the releases will be localized near the landward limit of the top of the GHSZ. These results indicate the possibility that hydrate dissociation and methane release may be both a consequence and a cause of climate change.
A multiple model assessment of seasonal climate forecast skill for applications
Authors: Lavers David , Luo Lifeng , Wood Eric F.
Published: December 2009

Skilful seasonal climate forecasts have potential to affect decision making in agriculture, health and water management. Organizations such as the National Oceanic and Atmospheric Administration (NOAA) are currently planning to move towards a climate services paradigm, which will rest heavily on skilful forecasts at seasonal (1 to 9 months) timescales from coupled atmosphere‐land‐ocean models. We present a careful analysis of the predictive skill of temperature and precipitation from eight seasonal climate forecast models with the joint distribution of observations and forecasts. Using the correlation coefficient, a shift in the conditional distribution of the observations given a forecast can be detected, which determines the usefulness of the forecast for applications. Results suggest there is a deficiency of skill in the forecasts beyond month‐1, with precipitation having a more pronounced drop in skill than temperature. At long lead times only the equatorial Pacific Ocean exhibits significant skill. This could have an influence on the planned use of seasonal forecasts in climate services and these results may also be seen as a benchmark of current climate prediction capability using (dynamic) couple models.
Oblique propagation of whistler mode waves in the chorus source region
Authors: Santolík O. , Gurnett D. A. , Pickett J. S. , Chum J. , Cornilleau‐Wehrlin N.
Published: December 2009

Whistler mode chorus has been shown to play a role in the process of local acceleration of electrons in the outer Van Allen radiation belt. Most of the quasi‐linear and nonlinear theoretical studies assume that the waves propagate parallel to the terrestrial magnetic field. We show a case where this assumption is invalid. We use data from the Cluster spacecraft to characterize propagation and spectral properties of chorus. The recorded high‐resolution waveforms show that chorus in the source region can be formed by a succession of discrete wave packets with decreasing frequency that sometimes change into shapeless hiss. These changes occur at the same time in the entire source region. Multicomponent measurements show that waves in both these regimes can be found at large angles to the terrestrial magnetic field. The hiss intervals contain waves propagating less than one tenth of a degree from the resonance cone. In the regime of discrete wave packets the peak of the wave energy density is found at a few degrees from the resonance cone in a broad interval of azimuth angles. The wave intensity increases with the distance from the magnetic field minimum along a given field line, indicating a gradual amplification of chorus in the source region.
Pebble abrasion during fluvial transport: Experimental results and implications for the evolution of the sediment load along rivers
Authors: Attal Mikaël , Lavé Jérôme
Published: December 2009

In actively eroding landscapes, fluvial abrasion modifies the characteristics of the sediment carried by rivers and consequently has a direct impact on the ability of mountain rivers to erode their bedrock and on the characteristics and volume of the sediment exported from upland catchments. In this experimental study, we use a novel flume replicating hydrodynamic conditions prevailing in mountain rivers to investigate the role played by different controlling variables on pebble abrasion during fluvial transport. Lithology controls abrasion rates and processes, with differences in abrasion rates exceeding two orders of magnitude. Attrition as well as breaking and splitting are efficient processes in reducing particle size. Mass loss by attrition increases with particle velocity but is weakly dependent on particle size. Fragment production is enhanced by the use of large particles, high impact velocities and the presence of joints. Based on our experimental results, we extrapolate a preliminary generic relationship between pebble attrition rate and transport stage (τ*/τ*c), where τ* = fluvial Shields stress and τ*c = critical Shields stress for incipient pebble motion. This relationship predicts that attrition rates are independent of transport stage for (τ*/τ*c) ≤ 3 and increase linearly with transport stage beyond this value. We evaluate the extent to which abrasion rates control downstream fining in several different natural settings. A simplified model predicts that the most resistant lithologies control bed load flux and fining ratio and that the concavity of transport‐limited river profiles should rarely exceed 0.25 in the absence of deposition and sorting.
Exploratory analysis of excitation‐emission matrix fluorescence spectra with self‐organizing maps as a basis for determination of organic matter removal efficiency at water treatment works
Authors: Bieroza Magdalena , Baker Andy , Bridgeman John
Published: December 2009

In the paper, the self‐organizing map (SOM) was employed for the exploratory analysis of fluorescence excitation‐emission data characterizing organic matter removal efficiency at 16 water treatment works in the UK. Fluorescence spectroscopy was used to assess organic matter removal efficiency between raw and partially treated (clarified) water to provide an indication of the potential for disinfection by‐products formation. Fluorescence spectroscopy was utilized to evaluate quantitative and qualitative properties of organic matter removal. However, the substantial amount of fluorescence data generated impeded the interpretation process. Therefore a robust SOM technique was used to examine the fluorescence data and to reveal patterns in data distribution and correlations between organic matter properties and fluorescence variables. It was found that the SOM provided a good discrimination between water treatment sites on the base of spectral properties of organic matter. The distances between the units of the SOM map were indicative of the similarity of the fluorescence samples and thus demonstrated the relative changes in organic matter content between raw and clarified water. The higher efficiency of organic matter removal was demonstrated for the larger distances between raw and clarified samples on the map. It was also shown that organic matter removal was highly dependent on the raw water fluorescence properties, with higher efficiencies for higher emission wavelengths in visible and UV humic‐like fluorescence centers.
Differential requirements for IL‐4/STAT6 signalling in CD4 T‐cell fate determination and Th2‐immune effector responses
Authors: Forbes Elizabeth , van Panhuys Nicholas , Min Booki , Le Gros Graham
Published: December 2009

Improved analytical tools have revealed that the development and expression of a Th2 immune response can be broken down into distinct stages with respect to the cytokine microenvironment that is required. Although IL‐4 and its STAT6‐signalling pathway are critical for the expression of Th2 effector immune responses in peripheral tissues such as the skin, lung and gut, IL‐4 and STAT6 signalling are not required for the initial generation of IL‐4‐producing Th2 cells in the lymph node. This finding reveals that we have yet to identify the key cytokine or microenvironment that stimulates the development of this most intriguing CD4+ T‐helper subset and emphasises the tissue specificity and timing of IL‐4/STAT6‐dependent Th2 effector responses.
The Development and Utilization of a Scale to Measure Adolescents' Attitudes Toward Peers Who Use Augmentative and Alternative Communication (AAC) Devices
Authors: Beck Ann R. , Thompson James R. , Kosuwan Kullaya , Prochnow Jessica M.
Published: December 2009

Purpose

Study 1 developed the Assessment of Attitudes Toward Augmentative and Alternative Communication—2 (AATAAC–2) to assess adolescents' attitudes toward peers who use AAC. Study 2 used the AATAAC–2 to examine influences of familiarity with people with disabilities; type of AAC device; and various combinations of gender of rater, AAC user, and communication partner on adolescents' attitudes.

Method

In Study 1, 194 adolescents viewed videotapes depicting adolescents using AAC, then completed AATAAC–2. Study 2 utilized 8 videotapes depicting 4 different gender combinations of AAC user and communication partner as experimental stimuli. Each gender combination was filmed twice: once with a static touch screen device, and once with a dynamic touch screen device. One-hundred thirty-six adolescents were randomly assigned to view 1 of the 8 videos. Participants then completed AATAAC–2.

Results

Study 1 demonstrated that AATAAC–2 has adequate psychometric properties. Raters' responses in Study 2 indicated no main effect of device type; girls were more positive than boys; and familiarity with peers with disabilities was associated with more positive attitudes. No 2-way interactions were significant; 3-way interaction of level of familiarity, gender, and type of device used was significant.

Conclusions

Familiarity and gender contribute to adolescents' attitudes; type of AAC device combined with these factors to influence attitudes.