bluuebunny/crossref_metadata_2025 huggingface dataset:
The internationalization of an Arab bank: The case of Ahli United Bank of Bahrain
Authors: Khan Golam Mostafa , Amine Lyn S. , Uddin Syed Jamal , Zaman Monir
Published: August 2011

Ahli United Bank of Bahrain (AUB) has “leapfrogged” over early stages of internationalization by means of multiple rapid acquisitions of competitors. Use of this high‐cost, high‐risk strategy is well known among companies with the resources to invest in international expansion, but its application has not yet been studied in depth among companies based in the Middle East. This theory‐driven case study examines the growth record of AUB, its place in the regional banking industry in the Gulf, and its successful internationalization as an Arab bank. The article concludes with a detailed assessment of managerial and theoretical implications arising from the case study, and proposes further research to understand better the process of internationalization by companies expanding from a base in the Middle East. © 2011 Wiley Periodicals, Inc.
Transnational corporations and the global water industry
Authors: Singh Satwinder , Dickson Keith
Published: August 2011

This article takes stock of foreign direct investment (FDI) undertaken by transnational corporations (TNCs) in the global water industry and examines the evidence on the impact of their operations in host countries. Between 1996 and 2006, approximately $12 billion were invested in water‐related sectors, of which 75% came from the private sector (including TNCs) from just four countries, while tentative calculations put the global share of investment by TNCs at 56%. Presently, 243 enterprises have interests in 409 water projects in 53 host countries. However, just six countries have received over half of the total investment. A survey of the evidence reports mixed results of the impact of TNCs' investment in host countries. It is argued that the biggest issue here is pricing, a dilemma that, alongside the privatization issue of host countries' water industry, is discussed in the concluding section. © 2011 Wiley Periodicals, Inc.
The rocky road to modernity: 20 years of the Russian capital market
Authors: Kuznetsova Olga , Kuznetsov Andrei , Mirkin Yakov M.
Published: August 2011

From a modest start almost 20 years ago, the Russian financial market has emerged as a major force in Eastern Europe and Central Asia. This article offers a retrospective account of the two decades of development of the financial sector in Russia, with an emphasis on the securities market; outlines the main stages in its development; and proposes an assessment of the capital market in comparison to other international markets. We conclude with an overview of the market's performance during the current financial crisis. © 2011 Wiley Periodicals, Inc.
PSA Testing and Its Relationship with Social Deprivation
Authors: Jackson Benjamin L. , Hope Katrina , Jackson Christopher L. , Williams Simon T.
Published: August 2011

Objective:

To determine whether social deprivation influenced the rate of PSA testing per head of male population within the catchment area of our institution.

Patients and methods:

We retrospectively collated all PSA tests performed by general practitioners within an 18-month period in the catchment area of our institution ( n = 10,695). PSA testing frequency within each lower super output area (LSOA) within the catchment area of our hospital was determined. The social deprivation of each LSOA was assessed using the Index of Multiple Deprivation 2007 index (IMD). Using these data, the percentage of men undergoing PSA tests in each LSOA was calculated as was the percentage of positive tests amongst those tested. Logistic regression analysis was performed with age and IMD 2007 scores as covariates.

Results:

Increasing IMD 2007 score was independently associated with a decreased likelihood of PSA testing (odds ratio 0.976 (95% confidence interval 0.959–0.994) p = 0.008). There was no association between IMD 2007 score and the rate of positive tests (odds ratio 0.997 (0.984–1.009) p = 0.60).

Conclusions:

Increasing levels of social deprivation demonstrate a small but significant association with a lower incidence of PSA testing in the catchment area of our institution. © 2011 British Association of Urological Surgeons. Published by Elsevier Ltd. All rights reserved.
Identifying ‘at risk’ women and the impact of maternal obesity on National Health Service maternity services
Authors: Heslehurst Nicola
Published: August 2011

Obesity is a public health concern worldwide, arising from multifaceted and complex causes that relate to individual choice and lifestyle, and the influences of wider society. In addition to a long-standing focus on both childhood and adult obesity, there has been more recent concern relating to maternal obesity. This review explores the published evidence relating to maternal obesity incidence and associated inequalities, the impact of obesity on maternity services, and associated guidelines. Epidemiological data comprising three national maternal obesity datasets within the UK have identified a significant increase in maternal obesity in recent years, and reflect broad socio-demographic inequalities particularly deprivation, ethnicity and unemployment. Obese pregnancies present increased risk of complications that require more resource intensive antenatal and perinatal care, such as caesarean deliveries, gestational diabetes, haemorrhage, infections and congenital anomalies. Healthcare professionals also face difficulties when managing the care of women in pregnancy as obesity is an emotive and stigmatising topic. There is a lack of good-quality evidence for effective interventions to tackle maternal obesity. Recently published national guidelines for the clinical management and weight management of maternal obesity offer advice for professionals, but acknowledge the limitations of the evidence base. The consequence of these difficulties is an absence of support services available for women. Further evaluative research is thus required to assess the effectiveness of interventions with women before, during and after pregnancy. Qualitative work with women will also be needed to help inform the development of more sensitive risk communication and women-centred services.
Delta-aminolevulinate dehydratase activity in red blood cells of rats infected withTrypanosoma evansi
Authors: FRANÇA RAQUELI T. , DA SILVA ALEKSANDRO S. , WOLKMER PATRÍCIA , OLIVEIRA VITOR A. , PEREIRA MARIA E. , LEAL MARTA L. R. , SILVA CÁSSIA B. , NUNES MATHEUS A. G. , DRESSLER VALDERI L. , MAZZANTI CINTHIA M. , MONTEIRO SILVIA G. , LOPES SONIA T. A.
Published: August 2011

The aim of this study was to evaluate the activity of delta-aminolevulinate dehydratase (δ-ALA-D) in red blood cells of rats infected withTrypanosoma evansiand establish its association with haematocrit, serum levels of iron and zinc and lipid peroxidation. Thirty-six male rats (Wistar) were divided into 2 groups with 18 animals each. Group A was non-infected while Group B was intraperitoneally infected, receiving 7·5×106trypomastigotes per animal. Each group was divided into 3 subgroups of 6 rats and blood was collected during different periods post-infection (p.i.) as follows: day 5 (A1 and B1), day 15 (A2 and B2) and day 30 PI (A3 and B3). Blood samples were collected by cardiac puncture to estimate red blood cell parameters (RBC),δ-ALA-D activity and serum levels of iron, zinc and thiobarbituric acid reactive substances (TBARS). Rats in group B showed a significant (P<0·05) reduction of RBC count, haemoglobin concentration and haematocrit at days 5 and 15 p.i. The activity ofδ-ALA-D in blood was significantly (P<0·001) increased at days 15 and 30 p.i.δ-ALA-D activity in blood had a significant (P<0·05) negative correlation with haematocrit (r=−0·61) and haemoglobin (r=−0·70) at day 15 p.i. There was a significant (P<0·05) decrease in serum iron and zinc levels and an increase in TBARS levels (P<0·05) during infection. Theδ-ALA-D activity in blood was negatively correlated with the levels of iron (r=−0·68) and zinc (r=−0·57) on day 30 p.i. It was concluded that the increased activity ofδ-ALA-D in blood might have occurred in response to the anaemia in remission as heme synthesis was enhanced.
Attention bias toward threat is associated with exaggerated fear expression and impaired extinction in PTSD
Authors: Fani N. , Tone E. B. , Phifer J. , Norrholm S. D. , Bradley B. , Ressler K. J. , Kamkwalala A. , Jovanovic T.
Published: August 2011

Background

Post-traumatic stress disorder (PTSD) develops in a minority of traumatized individuals. Attention biases to threat and abnormalities in fear learning and extinction are processes likely to play a critical role in the creation and/or maintenance of PTSD symptomatology. However, the relationship between these processes has not been established, particularly in highly traumatized populations; understanding their interaction can help inform neural network models and treatments for PTSD.

Method

Attention biases were measured using a dot probe task modified for use with our population; task stimuli included photographs of angry facial expressions, which are emotionally salient threat signals. A fear-potentiated startle paradigm was employed to measure atypical physiological response during acquisition and extinction phases of fear learning. These measures were administered to a sample of 64 minority (largely African American), highly traumatized individuals with and without PTSD.

Results

Participants with PTSD demonstrated attention biases toward threat; this attentional style was associated with exaggerated startle response during fear learning and early and middle phases of extinction, even after accounting for the effects of trauma exposure.

Conclusions

Our findings indicate that an attentional bias toward threat is associated with abnormalities in ‘fear load’ in PTSD, providing seminal evidence for an interaction between these two processes. Future research combining these behavioral and psychophysiological techniques with neuroimaging will be useful toward addressing how one process may modulate the other and understanding whether these phenomena are manifestations of dysfunction within a shared neural network. Ultimately, this may serve to inform PTSD treatments specifically designed to correct these atypical processes.
Inequality and culture: geographical differences in the access to cultural enrichment in Italy (1863–1992)
Authors: RASPADORI PAOLO
Published: August 2011

Based on the processing of statistical data concerning population and the major cultural infrastructures in the Italian regions from 1863 on, this article aims to demonstrate that the inhabitants of the ‘Mezzogiorno’ have had not only lesser incomes than those of the inhabitants of the Central and Northern regions, but also smaller chances to make use of Italy's cultural assets, considered in a broad sense. In the long run these disadvantages have strengthened the already high social disparities between the Centre, North and South of Italy and help to explain the roots of the dualism between the two parts of the country.
‘The good old days of the Cold War’: arguments used to admit or reject asylum seekers in the Netherlands, 1957–1967
Authors: WALAARDT TYCHO
Published: August 2011

This article examines the arguments used in the Netherlands to admit or exclude asylum seekers during the Cold War era. There is consensus that gaining asylum in the 1960s was not that difficult – especially when compared with current practices – because Cold War migrants were ‘the enemies of our enemy’. By analysing 36 detailed individual case files, this article questions the oft-sung mantra of an unproblematic asylum procedure for these ‘anti-communists’ in the Netherlands. We will see that the restrictive Dutch authorities frequently changed their anti-asylum decisions as a result of interventions from the outside. Outsiders' pleas, underpinned by a variety of arguments, often resulted in admission, but rarely in the attainment of refugee status.
‘The wife's administration of the earnings’? Working-class women and savings in the mid-nineteenth century
Authors: MALTBY JOSEPHINE
Published: August 2011

A survey of working-class women's activity as savers offers a new insight into their economic activity, opening questions about the sources inside and outside the family of the money saved by single and married women. It is relevant to a number of issues: the economic activity of married women and its relationship to the legal context in which they were operating – in particular before the Married Women's Property Acts of 1870 and 1882; the extent to which women's employment in the nineteenth century may have been mis-stated and/or under-reported; and the distribution of income within the working-class family. A study of investment patterns within two savings banks, one in Huddersfield and one in Sheffield in the mid-nineteenth century, suggests that working-class women may have been more active as savers than has been reported by earlier studies.
Nouns and verbs in Chintang: children's usage and surrounding adult speech
Authors: STOLL SABINE , BICKEL BALTHASAR , LIEVEN ELENA , PAUDYAL NETRA P. , BANJADE GOMA , BHATTA TOYA N. , GAENSZLE MARTIN , PETTIGREW JUDITH , RAI ICHCHHA PURNA , RAI MANOJ , RAI NOVEL KISHORE
Published: August 2011

Analyzing the development of the noun-to-verb ratio in a longitudinal corpus of four Chintang (Sino-Tibetan) children, we find that up to about age four, children have a significantly higher ratio than adults. Previous cross-linguistic research rules out an explanation of this in terms of a universal noun bias; instead, a likely cause is that Chintang verb morphology is polysynthetic and difficult to learn. This hypothesis is supported by the fact that the development of Chintang children's noun-to-verb ratio correlates significantly with the extent to which they show a similar flexibility with verbal morphology to that of the surrounding adults, as measured by morphological paradigm entropy. While this development levels off around age three, children continue to have a higher overall noun-to-verb ratio than adults. A likely explanation lies in the kinds of activities that children are engaged in and that are almost completely separate from adults' activities in this culture.
A neuronally based model of contrast gain adaptation in fly motion vision
Authors: RIVERA-ALVIDREZ ZULEY , LIN ICHI , HIGGINS CHARLES M.
Published: August 2011

Motion-sensitive neurons in the visual systems of many species, including humans, exhibit a depression of motion responses immediately after being exposed to rapidly moving images. This motion adaptation has been extensively studied in flies, but a neuronal mechanism that explains the most prominent component of adaptation, which occurs regardless of the direction of motion of the visual stimulus, has yet to be proposed. We identify a neuronal mechanism, namely frequency-dependent synaptic depression, which explains a number of the features of adaptation in mammalian motion-sensitive neurons and use it to model fly motion adaptation. While synaptic depression has been studied mainly in spiking cells, we use the same principles to develop a simple model for depression in a graded synapse. By incorporating this synaptic model into a neuronally based model for elementary motion detection, along with the implementation of a center-surround spatial band-pass filtering stage that mimics the interactions among a subset of visual neurons, we show that we can predict with remarkable success most of the qualitative features of adaptation observed in electrophysiological experiments. Our results support the idea that diverse species share common computational principles for processing visual motion and suggest that such principles could be neuronally implemented in very similar ways.
Searchers vs surveyors in estimating the monetary value of a QALY: resolving a nasty dilemma for NICE
Authors: Baker Rachel , Chilton Sue , Donaldson Cam , Jones-Lee Michael , Lancsar Emily , Mason Helen , Metcalf Hugh , Pennington Mark , Wildman John
Published: August 2011

Recently, for many health economics researchers, empirical estimation of the monetary valuation of a quality-adjusted life year (QALY) has become an important endeavour. Different philosophical and practical approaches to this have emerged. On the one hand, there is a view that, with health-care budgets set centrally, decision-making bodies within the system can iterate, from observation of a series of previous decisions, towards the value of a QALY, thus searching for such a value. Alternatively, and more consistent with the approach taken in other public sectors, individual members of the public are surveyed with the aim of directly eliciting a preference-based – also known as a willingness-to-pay-based (WTP-based) – value of a QALY. While the former is based on supply-side factors and the latter on demand, both in fact suffer from informational deficiencies. Sole reliance on either would necessitate an acceptance or accommodation of chronic inefficiencies in health-care resource allocation. On the basis of this observation, this paper makes the case that in order to approach optimal decision making in health-care provision, a framework incorporating and thus, to a degree, reconciling these two approaches is to be preferred.
Freedom in mass values: egocentric, humanistic, or both? Using Isaiah Berlin to understand a contemporary debate
Authors: Gustavsson Gina
Published: August 2011

Does an increasing emphasis on individual freedom in mass values erode or revitalize democratic societies? This paper offers a new approach to this debate by examining it through the lens of Isaiah Berlin, and his distinction between positive and negative freedom. I show that, contrary to the common assumption among scholars who study mass values regarding freedom, these do not consist of one dimension but two: negative and positive freedom. I also show that, while valuing negative liberty clearly leads a person to become more morally permissive and more condoning of non-compliance with legal norms, valuing positive liberty does not seem to have the same effects at all; in fact, it shows the very opposite relationship with respect to some of these attitudes. Thus, it matters what kind of freedom people value. The results rely on confirmatory factor and regression analyses on World Values Survey data from ten affluent Western countries in 2005–2006.
Role of thermosphere‐ionosphere coupling in a global ionospheric specification
Authors: Matsuo Tomoko , Araujo‐Pradere Eduardo A.
Published: August 2011

In this paper we present our recent research development in the area of ionospheric specification by means of data assimilation of ground‐based observations. NOAA's Total Electron Content specification methodology (namely, a Gauss‐Markov Kalmanfilter with an empirical model of the ionosphere as a background model) over the continental United States has lately been expanded to the multiregional domains and to the entire globe. Analyses of the global TEC maps reveal clear signatures of thermosphere‐ionosphere coupling, in both dynamical and compositional nature, even though the underlying specification methodology does not take thermospheric effects into account. This suggests that ground‐based observations of electron density contain some information about the state of the thermosphere. By using a thermosphere ionosphere general circulation model in a prototype Ensemble Kalman filter (EnKF), we examine the role of thermosphere‐ionosphere coupling in a global ionospheric specification. Observing system simulation experiments, designed for a global network of ionosondes, suggest that ionospheric data assimilation considerably benefits from self‐consistent treatment of thermosphere‐ionosphere coupling in a forecast model as well as in assimilation schemes, both of which can be achieved inherently by using the EnKF.
Tectonic evolution of a low‐angle extensional fault system from restored cross‐sections in the Northern Apennines (Italy)
Authors: Mirabella F. , Brozzetti F. , Lupattelli A. , Barchi M. R.
Published: August 2011

Broad geological and geophysical documentation is available on regional extensional systems driven by low‐angle normal faults. However, little information exists about the three‐dimensional geometry and the offset distribution of such extensional structures. We present a new set of balanced geological sections across the extensional fault system driven by the Altotiberina low‐angle normal fault in the Northern Apennines of Italy. We document this extensional system throughout a large set of surface (field surveys and geological maps) and subsurface data (seismic reflection profiles and boreholes). The subsurface data allowed us to define the fault deep geometry and to obtain its structural contours. The fault geometry is characterized by both along‐dip and along‐strike irregularities. In cross‐section, the fault displays a staircase trajectory with the shallowest part being dome‐shaped and flattened to horizontal. This bending could be due to the footwall uplift triggered by a footwall uploading greater than about 115 MPa. The sequential restoration of five geological cross‐sections yields a maximum extension of about 10 km accumulated over approximately 3 Ma. The resulting long‐term slip‐rate is about 3 mm/yr, which is of the same order as the present‐day extensional rate measured by GPS (2.5–3.0 mm/yr), suggesting an almost steady state extension over the last 3 Ma. The distribution of the extension values along the fault strike is bell‐shaped, as expected for a continuous surface.
Nicotinic α7 acetylcholine receptor-mediated currents are not modulated by the tryptophan metabolite kynurenic acid in adult hippocampal interneurons
Authors: Dobelis Peter , Varnell Andrew , Staley Kevin , Cooper Donald
Published: August 2011

The  tryptophan  metabolite,  kynurenic  acid (KYNA),  is  classically  known  to  be  an antagonist  of ionotropic glutamate receptors. Within the last decade several reports have been published suggesting that KYNA also blocks nicotinic acetylcholine receptors (nAChRs) containing the α7 subunit (α7*). Most of these reports involve either indirect measurements of KYNA effects on α7 nAChR function, or are reports of KYNA effects in complicated in vivo systems.  However, a recent report investigating KYNA interactions with α7 nAChRs failed to detect an interaction using direct measurements of α7 nAChRs function.  Further, it showed that a KYNA blockade of α7 nAChR stimulated GABA release (an indirect measure of α7 nAChR function) was not due to KYNA blockade of the α7 nAChRs. The current study measured the direct effects of KYNA on α7-containing nAChRs expressed on interneurons in the hilar and CA1 stratum radiatum regions of the mouse hippocampus and on interneurons in the CA1 region of the rat hippocampus.  Here we show that KYNA does not block α7* nACHRs using direct patch--clamp recording of α7 currents in adult brain slices.
Length of the active-site crossover loop defines the substrate specificity of ubiquitin C-terminal hydrolases for ubiquitin chains
Authors: Zhou Zi-Ren , Zhang Yu-Hang , Liu Shuai , Song Ai-Xin , Hu Hong-Yu
Published: August 2011

UCHs [Ub (ubiquitin) C-terminal hydrolases] are a family of deubiquitinating enzymes that are often thought to only remove small C-terminal peptide tails from Ub adducts. Among the four UCHs identified to date, neither UCH-L3 nor UCH-L1 can catalyse the hydrolysis of isopeptide Ub chains, but UCH-L5 can when it is present in the PA700 complex of the proteasome. In the present paper, we report that the UCH domain of UCH-L5, different from UCH-L1 and UCH-L3, by itself can process the K48-diUb (Lys48-linked di-ubiquitin) substrate by cleaving the isopeptide bond between two Ub units. The catalytic specificity of the four UCHs is dependent on the length of the active-site crossover loop. The UCH domain with a long crossover loop (usually >14 residues), such as that of UCH-L5 or BAP1 [BRCA1 (breast cancer early-onset 1)-associated protein 1], is able to cleave both small and large Ub derivatives, whereas the one with a short loop can only process small Ub derivatives. We also found that elongation of the crossover loop enables UCH-L1 to have isopeptidase activity for K48-diUb in a length-dependent manner. Thus the loop length of UCHs defines their substrate specificity for diUb chains, suggesting that the chain flexibility of the crossover loop plays an important role in determining its catalytic activity and substrate specificity for cleaving isopeptide Ub chains.
Receptor-isoform-selective insulin analogues give tissue-preferential effects
Authors: Vienberg Sara G. , Bouman Stephan D. , Sørensen Heidi , Stidsen Carsten E. , Kjeldsen Thomas , Glendorf Tine , Sørensen Anders R. , Olsen Grith S. , Andersen Birgitte , Nishimura Erica
Published: August 2011

The relative expression patterns of the two IR (insulin receptor) isoforms, +/− exon 11 (IR-B/IR-A respectively), are tissue-dependent. Therefore we have developed insulin analogues with different binding affinities for the two isoforms to test whether tissue-preferential biological effects can be attained. In rats and mice, IR-B is the most prominent isoform in the liver (>95%) and fat (>90%), whereas in muscles IR-A is the dominant isoform (>95%). As a consequence, the insulin analogue INS-A, which has a higher relative affinity for human IR-A, had a higher relative potency [compared with HI (human insulin)] for glycogen synthesis in rat muscle strips (26%) than for glycogen accumulation in rat hepatocytes (5%) and for lipogenesis in rat adipocytes (4%). In contrast, the INS-B analogue, which has an increased affinity for human IR-B, had higher relative potencies (compared with HI) for inducing glycogen accumulation (75%) and lipogenesis (130%) than for affecting muscle (45%). For the same blood-glucose-lowering effect upon acute intravenous dosing of mice, INS-B gave a significantly higher degree of IR phosphorylation in liver than HI. These in vitro and in vivo results indicate that insulin analogues with IR-isoform-preferential binding affinity are able to elicit tissue-selective biological responses, depending on IR-A/IR-B expression.
Ursodeoxycholic acid in cholestasis: linking action mechanisms to therapeutic applications
Authors: Roma Marcelo G. , Toledo Flavia D. , Boaglio Andrea C. , Basiglio Cecilia L. , Crocenzi Fernando A. , Sánchez Pozzi Enrique J.
Published: August 2011

UDCA (ursodeoxycholic acid) is the therapeutic agent most widely used for the treatment of cholestatic hepatopathies. Its use has expanded to other kinds of hepatic diseases, and even to extrahepatic ones. Such versatility is the result of its multiple mechanisms of action. UDCA stabilizes plasma membranes against cytolysis by tensioactive bile acids accumulated in cholestasis. UDCA also halts apoptosis by preventing the formation of mitochondrial pores, membrane recruitment of death receptors and endoplasmic-reticulum stress. In addition, UDCA induces changes in the expression of metabolizing enzymes and transporters that reduce bile acid cytotoxicity and improve renal excretion. Its capability to positively modulate ductular bile flow helps to preserve the integrity of bile ducts. UDCA also prevents the endocytic internalization of canalicular transporters, a common feature in cholestasis. Finally, UDCA has immunomodulatory properties that limit the exacerbated immunological response occurring in autoimmune cholestatic diseases by counteracting the overexpression of MHC antigens and perhaps by limiting the production of cytokines by immunocompetent cells. Owing to this multi-functionality, it is difficult to envisage a substitute for UDCA that combines as many hepatoprotective effects with such efficacy. We predict a long-lasting use of UDCA as the therapeutic agent of choice in cholestasis.
Plasma levels of sphingosine 1-phosphate are strongly correlated with haematocrit, but variably restored by red blood cell transfusions
Authors: Selim Samy , Sunkara Manjula , Salous Abdelghaffar K. , Leung Steve W. , Berdyshev Evgeny V. , Bailey Alison , Campbell Charles L. , Charnigo Richard , Morris Andrew J. , Smyth Susan S.
Published: August 2011

Anaemia and RBC (red blood cell) transfusion may be associated with worse clinical outcomes, especially with longer blood storage duration prior to transfusion. The mechanisms underlying these harmful effects are unknown. RBCs have been proposed to buffer plasma S1P (sphingosine 1-phosphate), a lysophospholipid essential for the maintenance of endothelial integrity and important in the regulation of haematopoietic cell trafficking. The present study examined the effect of anaemia, RBC transfusion and RBC storage duration on plasma S1P levels. Plasma S1P from 30 individuals demonstrated a linear correlation with Hct (haematocrit; R2=0.51, P<0.001) with no evidence for a plateau at Hct values as low as 19%. RBC transfusion in 23 anaemic patients with baseline mean Hct of 22.2±0.34% (value is the mean±S.D.) increased Hct to 28.3±0.6% at 72 h. Despite an Hct increase, RBC transfusion failed to elevate plasma S1P consistently. A trend towards an inverse correlation was observed between RBC storage duration and the post-transfusion increase in plasma S1P. After 30 days of storage, RBC S1P decreased to 19% of that observed in fresh (3–7-day-old) RBC segments. RBC membranes contain low levels of both S1P phosphatase and S1P lyase activities that may account for the decline in S1P levels with storage. Our results support a role for RBCs in buffering plasma S1P and identify a disturbance in the capacity after transfusion. Changes in S1P content may contribute to an RBC storage lesion. Further studies should investigate the clinical significance of alterations in circulating S1P levels and the potential value of enriching stored RBCs with S1P.
Extremal quantum protocols
Authors: D’Ariano Giacomo Mauro , Perinotti Paolo , Sedlák Michal
Published: August 2011

Generalized quantum instruments correspond to measurements where the input and output are either states or more generally quantum circuits. These measurements describe any quantum protocol including games, communications, and algorithms. The set of generalized quantum instruments with a given input and output structure is a convex set. Here, we investigate the extremal points of this set for the case of finite dimensional quantum systems and generalized instruments with finitely many outcomes. We derive algebraic necessary and sufficient conditions for extremality.
Turbulent diffusion in tall tubes. I. Models for Rayleigh-Taylor instability
Authors: Lawrie Andrew G. W. , Dalziel Stuart B.
Published: August 2011

Rayleigh-Taylor instability in high-aspect-ratio domains has been studied experimentally and a hierarchy of modelling approaches has been used to understand the dynamics of the problem. Part I examines the simplest case of initially homogenous layers above and below the Rayleigh-Taylor unstable interface. Part II examines the more complex case where one layer is stably stratified in density. Here, in Part I, we develop models for turbulent mixing induced by Rayleigh-Taylor instability based on a diffusion equation for density. By considering the force balance in the problem, and using Prandtl’s mixing length hypothesis, we compute a non-constant turbulent diffusivity, and this leads to a non-linear diffusion equation. We reiterate a h~t25 scaling and use this to develop a new similarity solution to the nonlinear diffusion equation in an infinite domain. To match experimental boundary conditions of a finite domain, we use numerical integration, and finally, we compare with implicit large eddy simulation.
The minimum energy decay rate in quasi-isotropic grid turbulence
Authors: Davidson P. A.
Published: August 2011

We consider high Reynolds number, freely-decaying, isotropic turbulence in which the large scales evolve in a self-similar manner when normalized by the integral scales, u and ℓ. As it is well known, a range of possible behaviors may be observed depending on the form of the longitudinal velocity correlation at large separation, u2f∞=u2f(r→∞). We consider the cases u2f∞=cmr-m,2≤m≤6, whose spectral counterpart is E(k→0)~cmkm-1 for m<6, with or without a lnk correction, and E(k→0)~Ik4 for m=6. (I is Loitsyansky’s integral.) It has long been known that the cm are invariants for m<6, which demands u2ℓm=constant during the decay. This, in turn, sets the energy decay rate as u2~t-(1-p)2m/(m+2), where p is the power-law exponent for the normalized dissipation rate, ɛℓ/ɛℓu3u3~t-p, observed empirically to be a small positive number in grid turbulence. We systematically explore the properties of these different classes of turbulence and arrive at the following conclusions. (i) The invariance of cm is a direct consequence of linear momentum conservation for m≤4, and angular momentum conservation for m=5. (ii) The classical spectra of Saffman, E(k→0)~c3k2, and Batchelor, E(k→0)~Ik4, are robust in the sense that they emerge from a broad class of initial conditions. In particular, it is necessary only that 〈ωiω'j〉∞≤O(r-8) at t=0. The non-classical spectra (m=2,4,5), on the other hand, require very specific initial conditions in order to be realized, of the form 〈ωiω'j〉∞=O(r-(m+2)). (Note the equality rather than the inequality here.) This makes the non-classical spectra less likely to be observed in practice. (iii) The case of m=2, which is usually associated with the u2~t-1 decay law, is pathological in a number of respects. For example, its spectral tensor diverges as k→0, and the long-range correlations 〈uiu'j〉∞=O(r-2) are too strong to be a consequence of the Biot-Savart law. (It is the Biot-Savart law that lies behind the long-range correlations in the classical spectra.) This suggests that m=2 spectra are unlikely to manifest themselves in grid turbulence. A detailed review of the available experimental data is consistent with this assertion. We conclude, therefore, that the minimum energy decay rate in homogeneous grid turbulence is most probably that of Saffman turbulence.
Charge trapping-detrapping mechanism of barrier breakdown in MgO magnetic tunnel junctions
Authors: Amara-Dababi S. , Sousa R. C. , Chshiev M. , Béa H. , Alvarez-Hérault J. , Lombard L. , Prejbeanu I. L. , Mackay K. , Dieny B.
Published: August 2011

Endurance of MgO-based magnetic tunnel junctions has been studied using a time-dependent dielectric breakdown method. Series of successive electrical pulses were applied until electrical breakdown of the tunnel barrier. We show that two electrical breakdown regimes exist depending on the time interval Δt between pulses compared to a characteristic escape time of trapped electrons τ0 ∼ 100 ns. For Δt < τ0, breakdown is caused by a high average charge trapped in the barrier. For Δt > τ0, breakdown is ascribed to large temporal modulation of trapped charges causing alternating stress in the barrier oxide. Between these two regimes, the tunnel junctions reach a very high endurance.
Nonlinear vocal fold dynamics resulting from asymmetric fluid loading on a two-mass model of speech
Authors: Erath Byron D. , Zañartu Matías , Peterson Sean D. , Plesniak Michael W.
Published: August 2011

Nonlinear vocal fold dynamics arising from asymmetric flow formations within the glottis are investigated using a two-mass model of speech with asymmetric vocal fold tensioning, representative of unilateral vocal fold paralysis. A refined theoretical boundary-layer flow solver is implemented to compute the intraglottal pressures, providing a more realistic description of the flow than the standard one-dimensional, inviscid Bernoulli flow solution. Vocal fold dynamics are investigated for subglottal pressures of 0.6 < ps < 1.5 kPa and tension asymmetries of 0.5 < Q < 0.8. As tension asymmetries become pronounced the asymmetric flow incites nonlinear behavior in the vocal fold dynamics at subglottal pressures that are associated with normal speech, behavior that is not captured with standard Bernoulli flow solvers. Regions of bifurcation, coexistence of solutions, and chaos are identified.
One hundred anode microchannel plate ion detector
Authors: He Yi , Poehlman John F. , Alexander Andrew W. , Boraas Kirk , Reilly James P.
Published: August 2011

A one-hundred-anode microchannel plate detector is constructed on a 10 cm × 15 cm printed circuit board and attached to a homebuilt matrix assisted laser desorption ionization (MALDI) time-of-flight mass spectrometer. Ringing and cross talk between anodes have been successfully eliminated and preliminary mass spectra of peptide ions recorded. With one hundred anodes on the printed circuit board, spatial information about the ion beam can also be readily determined with this detector. During operation, the detector anode assembly loses sensitivity after ions strike it for a considerable period of time due to charging of the non-conductive regions between anodes. However, this effect can be minimized by deflecting matrix ions away from the detector.
Dielectric maximum temperature non-monotonic behavior in unaxial Sr0.75Ba0.25Nb2O6 relaxor seen via acoustic emission
Authors: Dul’kin E. , Kojima S. , Roth M.
Published: August 2011

[100] oriented Sr0.75Ba0.25Nb2O6 relaxor crystals have been studied by means of acoustic emission (AE) over a wide 20–400 °C temperature range. Both the Burns temperature, Td = 350 °C, and the intermediate temperature, T* = 183°C, and the susceptibility maximum temperature, Tm (59 °C on heating and 47 °C on cooling), have been successfully detected. Dependent upon the external electric field, the Tm exhibits a local minimum near 0.25 kV/cm accompanied by pronounced AE maximum in a manner which had recently been detected in Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 by Dul’kin et al. [Appl. Phys. Lett. 94, 252904 (2009)] and in Pb(Sc1/2Ta1/2)O3 by Dul’kin et al. [Phys. Rev. B 82, 180101(R) (2010)], whereas the T* increases monotonically, similar to that which had recently been revealed in BaTiO3 by Dul’kin et al. [Appl. Phys. Lett. 97, 032903 (2010)] with a rate of 7.5 K cm/kV. An observed Tm behavior is discussed from the point of view of the existence of the random electric field components along the [100] direction in Sr0.75Ba0.25Nb2O6 crystals.
Turbulent diffusion in tall tubes. II. Confinement by stratification
Authors: Lawrie Andrew G. W. , Dalziel Stuart B.
Published: August 2011

Rayleigh-Taylor instability between two initially homogeneous layers has been shown to evolve in a self similar manner in high-aspect-ratio domains, and in Part I, we demonstrated close agreement between experimental measurements and a range of modelling approaches. However, changing the initial conditions such that one layer is linearly stably stratified in density introduces an additional length scale to the problem and breaks the global self-similarity seen in the case of homogeneous layers. Here, in Part II, we explore the development of this modified instability. We again compare experimental measurements with a range of modelling approaches, achieving excellent agreement assuming a one-dimensional nonlinear turbulent diffusion, and demonstrating that implicit large eddy simulations are able to capture the detailed development despite limitations in the manner in which both mass and momentum are redistributed by numerical rather than molecular diffusion.
Analysis of thermal band gap variations of PbS quantum dots by Fourier transform transmission and emission spectroscopy
Authors: Ullrich B. , Wang J. S. , Brown G. J.
Published: August 2011

Fourier transmission and emission spectroscopy was employed in the range from 5 to 300 K to measure the thermal band gap shift of 4.7 nm PbS quantum dots. The analytical comparison of fits carried out with the expressions of Varshni and Fan revealed limited accuracy of the Varshni fitting parameters. Evidence is presented that transmission spectroscopy in conjunction with the Fan model concurs with the microscopic material features, resulting in a tool to determine intrinsic properties of quantum dots.
Note: High speed optical profiler based on a phase-shifting technique using frequency-scanning lasers
Authors: Kim Jong-Ahn , Kang Chu-Shik , Jin Jonghan , Eom Cheon , Jang Roma , Kim Jae Wan
Published: August 2011

We present a high speed optical profiler (HSOP) using frequency-scanning lasers for three-dimensional profile measurements of microscopic structures. To improve upon previous techniques for implementing the HSOP, we developed frequency-scanning lasers and a compact microscopic interferometer. The controller of the HSOP was also modified to generate proper phase-shifting steps. For measurements of step height specimens, the HSOP showed results comparable with a commercial optical profiler, even with much higher measurement speeds (up to 30 Hz). The typical repeatability of step height measurement was less than 1 nm. We also present measurements of microscopic structures to verify the HSOP's ability to perform high speed inline inspection for the semiconductor and flat-panel display industries.
Xenon excimer emission from multicapillary discharges in direct current mode
Authors: Lee Byung-Joon , Rahaman Hasibur , Nam Sang Hoon , Giapis Konstantinos P. , Iberler Marcus , Jacoby Joachim , Frank Klaus
Published: August 2011

Microdischarges in xenon have been generated in a pressure range of 400–1013 mbar with a fixed flow rate of 100 sccm. These microdischarges are obtained from three metallic capillary tubes in series for excimer emission. Total discharge voltage is thrice as large as that of a single capillary discharge tube at current levels of up to 12 mA. Total spectral irradiance of vacuum ultraviolet (VUV) emission also increases significantly compared to that of the single capillary discharge. Further, the irradiance of the VUV emission is strongly dependent on pressure as well as the discharge current.
Quantum-classical simulation of electron localization in negatively charged methanol clusters
Authors: Mones Letif , Rossky Peter J. , Turi László
Published: August 2011

A series of quantum molecular dynamics simulations have been performed to investigate the energetic, structural, dynamic, and spectroscopic properties of methanol cluster anions, [(CH3OH)n]−, (n = 50–500). Consistent with the inference from photo-electron imaging experiments, we find two main localization modes of the excess electron in equilibrated methanol clusters at ∼200 K. The two different localization patterns have strikingly different physical properties, consistent with experimental observations, and are manifest in comparable cluster sizes to those observed. Smaller clusters (n ≤ 128) tend to localize the electron in very weakly bound, diffuse electronic states on the surface of the cluster, while in larger ones the electron is stabilized in solvent cavities, in compact interior-bound states. The interior states exhibit properties that largely resemble and smoothly extrapolate to those simulated for a solvated electron in bulk methanol. The surface electronic states of methanol cluster anions are significantly more weakly bound than the surface states of the anionic water clusters. The key source of the difference is the lack of stabilizing free hydroxyl groups on a relaxed methanol cluster surface. We also provide a mechanistic picture that illustrates the essential role of the interactions of the excess electron with the hydroxyl groups in the dynamic process of the transition of the electron from surface-bound states to interior-bound states.
Breaking the carbon dimer: The challenges of multiple bond dissociation with full configuration interaction quantum Monte Carlo methods
Authors: Booth George H. , Cleland Deidre , Thom Alex J. W. , Alavi Ali
Published: August 2011

The full configuration interaction quantum Monte Carlo (FCIQMC) method, as well as its “initiator” extension (i-FCIQMC), is used to tackle the complex electronic structure of the carbon dimer across the entire dissociation reaction coordinate, as a prototypical example of a strongly correlated molecular system. Various basis sets of increasing size up to the large cc-pVQZ are used, spanning a fully accessible N-electron basis of over 1012 Slater determinants, and the accuracy of the method is demonstrated in each basis set. Convergence to the FCI limit is achieved in the largest basis with only \documentclass[12pt]{minimal}\begin{document}$\mathcal {O}[10^7]$\end{document}O[107] walkers within random errorbars of a few tenths of a millihartree across the binding curve, and extensive comparisons to FCI, CCSD(T), MRCI, and CEEIS results are made where possible. A detailed exposition of the convergence properties of the FCIQMC methods is provided, considering convergence with elapsed imaginary time, number of walkers and size of the basis. Various symmetries which can be incorporated into the stochastic dynamic, beyond the standard abelian point group symmetry and spin polarisation are also described. These can have significant benefit to the computational effort of the calculations, as well as the ability to converge to various excited states. The results presented demonstrate a new benchmark accuracy in basis-set energies for systems of this size, significantly improving on previous state of the art estimates.
Inner-shell single and double ionization potentials of aminophenol isomers
Authors: Kryzhevoi Nikolai V. , Santra Robin , Cederbaum Lorenz S.
Published: August 2011

A comprehensive study of single and double core ionization potentials of the aminophenol molecule is reported. The role of relaxation, correlation, relativistic, and basis set effects in these potentials is clarified. Special attention is paid to the isomer dependence of the single and double core ionization potentials. Some of them are also compared with the respective values of the phenol and aniline molecules. It is shown that the core level single ionization potentials of the para-, meta-, and ortho-aminophenol molecules differ only slightly from each other, rendering these structural isomers challenging to distinguish for conventional x-ray photoelectron spectroscopy. In contrast, the energy needed to remove two core electrons from different atoms depends noticeably on the mutual arrangement and even on the relative orientations of the hydroxyl and amine groups. Together with the electrostatic repulsion between the two core holes, relaxation effects accompanying double core ionization play a crucial role here. The pronounced sensitivity of the double ionization potentials, therefore, enables a spectroscopic characterization of the electronic structure of aminophenol isomers by means of x-ray two-photon photoelectron spectroscopy.
Analytical model for electromagnetic cascades in rotating electric field
Authors: Nerush E. N. , Bashmakov V. F. , Kostyukov I. Yu.
Published: August 2011

Electromagnetic cascades attract a lot of attention as an important quantum electrodynamics effect that will reveal itself in various electromagnetic field configurations at ultrahigh intensities. We study cascade dynamics in rotating electric field analytically and numerically. The kinetic equations for the electron-positron plasma and gamma-quanta are formulated. The scaling laws are derived and analyzed. For the cascades arising far above the threshold the dependence of the cascade parameters on the field frequency is derived. The spectra of high-energy cascade particles are calculated. The analytical results are verified by numerical simulations.