bluuebunny/crossref_metadata_2025 huggingface dataset:
Abdominal Drains in Liver Transplantation: Useful Tool or Useless Dogma? A Matched Case-Control Study
Authors: de Rougemont Olivier , Dutkowski Philipp , Weber Markus , Clavien Pierre-Alain
Published: December 2008

Abstract

On the basis of the growing evidence from randomized trials that routine prophylactic drainage is unnecessary in liver surgery or even harmful in chronic liver disease, we challenged the concept of prophylactic drainage in orthotopic liver transplantation (OLT). Since September 2006, we omitted drains in every patient who underwent OLT, regardless of the procedure. Thirty-five cadaveric OLTs were performed during a 12-month period. These patients were matched 1:2 with 70 patients who had prophylactic drainage after OLT according to donor/recipient age, recipient gender, recipient body mass index, and Model for End-Stage Liver Disease (MELD) score. Endpoints were postoperative morbidity, in-hospital mortality, intensive care unit (ICU), and hospital stay. Complications were graded according to a therapy-oriented classification (grades I-V). Both groups (no drainage, n = 35; drainage, n = 70) were comparable in terms of median donor age (47.5 versus 51.0 years), recipient age (50.6 versus 52.0 years), MELD score (18 versus 14), and body mass index (25.3 versus 26 kg/m2). Because of the increasing shortage of organs, more marginal grafts were used in the recent period (ie, no-drainage group): 49% (17/35) versus 27% (19/70; P = 0.04). Major complications were not different between groups: grade 3a (endoscopic/radiological intervention) in 20% (7/35) versus 16% (11/70; not significant), grade 3b (surgical intervention) in 23% (8/35) versus 17% (12/70; not significant), grade 4a (ICU therapy, intermittent hemodialysis) in 34% (12/35) versus 21% (15/70; not significant), grade 4b (multiorgan failure) in 14% (5/35) versus 10% (7/70; not significant), and grade 5 (death) in 6% (2/35) versus 7% (5/70; not significant). This matched case study challenges the dogma of prophylactic drainage after OLT. A no-drain strategy provided no disadvantages despite increased use of extended criteria donors in the no-drainage group. Prophylactic drainage appears unnecessary on a routine basis. Liver Transpl 15:96–101, 2009. © 2008 AASLD.
The FHA‐containing protein GarA acts as a phosphorylation‐dependent molecular switch in mycobacterial signaling
Authors: England Patrick , Wehenkel Annemarie , Martins Sonia , Hoos Sylviane , André-Leroux Gwénaëlle , Villarino Andrea , Alzari Pedro M.
Published: December 2008

MINT‐6804218: GarA (uniprotkb:P64897) and GarA (uniprotkb:P64897) bind (MI:0407) by isothermal titration calorimetry (MI:0065)
Nitric oxide accumulation is required to protect against iron‐mediated oxidative stress in frataxin‐deficient Arabidopsis plants
Authors: Martin Mariana , Colman María José Rodríguez , Gómez-Casati Diego F. , Lamattina Lorenzo , Zabaleta Eduardo Julián
Published: December 2008

Frataxin is a mitochondrial protein that is conserved throughout evolution. In yeast and mammals, frataxin is essential for cellular iron (Fe) homeostasis and survival during oxidative stress. In plants, frataxin deficiency causes increased reactive oxygen species (ROS) production and high sensitivity to oxidative stress. In this work we show that a knock‐down T‐DNA frataxin‐deficient mutant of Arabidopsis thaliana (atfh‐1) contains increased total and organellar Fe levels. Frataxin deficiency leads also to nitric oxide (NO) accumulation in both, atfh‐1 roots and frataxin null mutant yeast. Abnormally high NO production might be part of the defence mechanism against Fe‐mediated oxidative stress.
Novel function of C5 protein as a metabolic stabilizer of M1 RNA
Authors: Kim Yool , Lee Younghoon
Published: December 2008

Escherichia coli RNase P is a ribonucleoprotein composed of a large RNA subunit (M1 RNA) and a small protein subunit (C5 protein). We examined if C5 protein plays a role in maintaining metabolic stability of M1 RNA. The sequestration of C5 protein available for M1 RNA binding reduced M1 RNA stability in vivo, and its reduced stability was recovered via overexpression of C5 protein. In addition, M1 RNA was rapidly degraded in a temperature‐sensitive C5 protein mutant strain at non‐permissive temperatures. Collectively, our results demonstrate that the C5 protein metabolically stabilizes M1 RNA in the cell.
Stress induces tRNA cleavage by angiogenin in mammalian cells
Authors: Fu Hanjiang , Feng Junjun , Liu Qin , Sun Fang , Tie Yi , Zhu Jie , Xing Ruiyun , Sun Zhixian , Zheng Xiaofei
Published: December 2008

tRNAs play a central role in protein translation, acting as the carrier of amino acids. By cloning microRNAs, we unexpectedly obtained some tRNA fragments generated by tRNA cleavage in the anticodon loop. These tRNA fragments are present in many cell lines and different mouse tissues. In addition, various stress conditions can induce this tRNA cleavage event in mammalian cells. More importantly, angiogenin (ANG), a member of RNase A superfamily, appears to be the nuclease which cleaves tRNAs into tRNA halves in vitro and in vivo. These results imply that angiogenin plays an important physiological role in cell stress response, except for the known function of inducing angiogenesis.
Characterization of the Caenorhabditis elegansIslet LIM‐homeodomain ortholog, lim‐7
Authors: Voutev Roumen , Keating Ryan , Jane Albert Hubbard E. , Vallier Laura G.
Published: December 2008

lim‐7 is one of seven Caenorhabditis elegans LIM‐homeodomain (LIM‐HD)‐encoding genes and the sole Islet ortholog. LIM‐HD transcription factors, including Islets, function in neuronal and non‐neuronal development across diverse phyla. Our results show that a lim‐7 deletion allele causes early larval lethality with terminal phenotypes including uncoordination, detached pharynx, constipation and morphological defects. A lim‐7(+) transgene rescues lethality but not adult sterility. A lim‐7(+) reporter in the full genomic context is expressed in all gonadal sheath cells, URA neurons, and additional cells in the pharyngeal region. Finally, we identify a 45‐bp regulatory element in the first intron that is necessary and sufficient for lim‐7 gonadal sheath expression.
Low‐molecular‐weight heparin versus intravenous immunoglobulin for recurrent abortion associated with antiphospholipid antibody syndrome
Authors: Dendrinos Spiros , Sakkas Evangelos , Makrakis Evangelos
Published: December 2008

Objective

To compare low‐molecular‐weight (LMW) heparin plus low‐dose aspirin with intravenous immunoglobulin (IVIG) in the treatment of antiphospholipid antibody syndrome in women with recurrent spontaneous abortions before 10 weeks of gestation.

Method

This prospective, multicenter trial conducted between 2002 and 2006 included 85 patients aged 18–39 years. The women were allocated randomly to receive LMW heparin plus low‐dose aspirin, or IVIG. Data were compared using the t test and Fisher exact test.

Results

The women treated with LMW heparin plus low‐dose aspirin had a higher rate of live births than those treated with IVIG (P = 0.003). Of those who completed the study, 29/40 (72.5%) and 15/38 (39.5%), respectively, had live births. Intent‐to‐treat analysis revealed a significant difference between the 2 groups (OR 1.802; 95%CI, 1.14–2.84; P = 0.007).

Conclusions

LMW heparin plus low‐dose aspirin resulted in a higher live birth rate than IVIG in the treatment of antiphospholipid antibody syndrome in women with recurrent abortion.
Introduction of CenteringPregnancy in a Public Health Clinic
Authors: Klima Carrie , Norr Kathleen , Vonderheid Susan , Handler Arden
Published: December 2008

CenteringPregnancy is a promising group visit prenatal care innovation that provides substantial health promotion content. Elements unique to group care include peer support and self‐management training and activities. CenteringPregnancy was introduced at a large public health clinic serving predominantly low‐income African American pregnant women. All prenatal care at this clinic was provided by certified nurse‐midwives, and all providers were trained in the CenteringPregnancy model. One hundred and ten women received prenatal care in CenteringPregnancy groups. Focus groups of pregnant women, providers, and health center staff reported that the program benefited women despite implementation challenges such as scheduling changes. Compared to women in individual care, women in CenteringPregnancy had significantly more prenatal visits, increased weight gain, increased breast feeding rates, and higher overall satisfaction. This pilot project demonstrated that CenteringPregnancy can be implemented in a busy public health clinic serving predominantly low‐income pregnant women and is associated with positive health outcomes.
The Practice of Prelacteal Feeding to Newborns Among Hindu and Muslim Families
Authors: McKenna Kathleen M. , Shankar Rani T.
Published: December 2008

A 21‐year‐old gravida 2, para 1001 female at 39 weeks and 4/7 days gestation was admitted to the labor and birth unit in active labor. She moved to the United States from Pakistan during the last 2 months of her pregnancy. She is a practicing Muslim. Her sister‐in‐law accompanied her. She had an uncomplicated antenatal course, except for iron deficiency anemia (at admission, her hemoglobin was 9.40 g/dl and hematocrit was 29.1%). She had an epidural anesthetic for pain relief. Her first stage of labor was 9 hours, her second stage was 5 minutes, and her third stage was 15 minutes. The baby was born over an intact perineum with Apgar scores of 9 and 9, respectively, and weighed 3,095 g. The baby was placed on the mother's abdomen, and once cleaned and wrapped in a blanket on the infant warmer, the baby was held by the mother. When asked her infant feeding preferences, the mother expressed eagerness to breastfeed. However, before initiation of breastfeeding, the sister‐in‐law asked the midwife permission to feed the baby a sweet (a drop of brown sugar). The sister‐in‐law explained that it was customary in Muslim families that “the first thing to touch the baby's mouth should be something sweet.” After the midwife agreed, the sister‐in‐law said a prayer. As requested by the mother, the baby was fed the drop of sweet. Breastfeeding was initiated within an hour postpartum. She reported exclusively breastfeeding from her birth until her 6‐week postpartum visit.
The Interaction Between Chronic Stress and Pregnancy: Preterm Birth from A Biobehavioral Perspective
Authors: Latendresse Gwen
Published: December 2008

Women's health care providers are increasingly aware that chronic stressors—such as poverty, ongoing perceived stress and anxiety, intimate partner violence, and experiences of racism—are associated with an increased incidence of preterm birth in the United States. It is important to increase our understanding of the explanatory pathways involved in these associations. This article discusses the concepts of stress, chronic stress response, allostatic load, the physiology of labor initiation, and the pathophysiologic interactions that may contribute to the occurrence of chronic stress‐related preterm birth. Implications for future research and interventions are explored.
Functional Movement Training for Recurrent Low Back Pain: Lessons From a Pilot Randomized Controlled Trial
Authors: Schenkman Margaret L. , Jordan Sharon , Akuthota Venu , Roman Matthew , Kohrt Wendy M. , Hearty Thomas , Cleary Catherine , Backstrom Karen Maloney
Published: December 2008

Objective

Despite considerable effort to reduce low back pain (LBP), approximately 60% of patients have recurrence after their first episode. The high rate of recurrence suggests that more effective intervention approaches are needed. This randomized, controlled feasibility trial was designed to compare disability, physical functional capacity, and pain outcomes at 2, 6, and 12 months for 2 conventional and 1 novel physical therapy (functional movement training) intervention for recurrent LBP.

Design

Randomized, controlled feasibility trial.

Setting

University hospital outpatient physical therapy clinic.

Participants

Sixty‐one participants (60% female) with recurrent LBP.

Interventions

Subjects were randomized to 1 of 3 intervention groups: group 1 had a single session consisting of standard back pain education; group 2 had 6 sessions in 8 weeks of conventional physical therapy; and group 3 had 6 sessions in 8 weeks of a novel method of functional movement training. Change from baseline was used to determine within‐group changes and between‐group differences for participants who finished each time point (2, 6, and 12 months). Changes were evaluated using analysis of variance and Newman‐Keuls post hoc analysis.

Main Outcome Measures

The primary outcome measure was the novel Continuous Scale Physical Functional Performance test (CS‐PFP), a measure of actual physical functional capacity. Secondary measures included the revised Oswestry Disability Index, a measure of pain‐related disability, the Roland Morris Disability Questionnaire, and a standard visual analogue pain scale.

Results

Of the participants, 67% provided data at 2 months and 44% provided information at 12 months. Raw change scores were evaluated at 2, 6, and 12 months. While no statistical significance was reached with any outcome measure, the trends suggested little change for group 1 (education) and suggested that greatest improvement in function may occur in group 3 (functional movement training). In particular, at 2 months, the CS‐PFP change scores revealed a trend (P=.072) toward greater improvement in groups 2 (conventional physical therapy) and 3 (functional movement training) compared with group 1. At 12 months, Oswestry Disability Index and CS‐PFP scores also trended toward significance for groups 2 and 3 (P=.7 and .9, respectively). Mean change scores were also calculated and revealed groups 2 and 3 had improved by 2 months and this improvement remained stable at the 1‐year mark. Trends in the direction of best improvement occurred for those in the functional movement training group.

Conclusion

A large‐scale randomized, controlled trial is warranted to determine whether an intervention based on functional movement training is superior to conventional, impairment‐based intervention for individuals with recurrent LBP.
Changes in the North Atlantic Oscillation influence CO2 uptake in the North Atlantic over the past 2 decades
Authors: Thomas Helmuth , Friederike Prowe A. E. , Lima Ivan D. , Doney Scott C. , Wanninkhof Rik , Greatbatch Richard J. , Schuster Ute , Corbière Antoine
Published: December 2008

Observational studies report a rapid decline of ocean CO2 uptake in the temperate North Atlantic during the last decade. We analyze these findings using ocean physical‐biological numerical simulations forced with interannually varying atmospheric conditions for the period 1979–2004. In the simulations, surface ocean water mass properties and CO2 system variables exhibit substantial multiannual variability on sub‐basin scales in response to wind‐driven reorganization in ocean circulation and surface warming/cooling. The simulated temporal evolution of the ocean CO2 system is broadly consistent with reported observational trends and is influenced substantially by the phase of the North Atlantic Oscillation (NAO). Many of the observational estimates cover a period after 1995 of mostly negative or weakly positive NAO conditions, which are characterized in the simulations by reduced North Atlantic Current transport of subtropical waters into the eastern basin and by a decline in CO2 uptake. We suggest therefore that air‐sea CO2 uptake may rebound in the eastern temperate North Atlantic during future periods of more positive NAO, similar to the patterns found in our model for the sustained positive NAO period in the early 1990s. Thus, our analysis indicates that the recent rapid shifts in CO2 flux reflect decadal perturbations superimposed on more gradual secular trends. The simulations highlight the need for long‐term ocean carbon observations and modeling to fully resolve multiannual variability, which can obscure detection of the long‐term changes associated with anthropogenic CO2 uptake and climate change.
Variability of earthquake nucleation in continuum models of rate‐and‐state faults and implications for aftershock rates
Authors: Kaneko Y. , Lapusta N.
Published: December 2008

Using two continuum models of rate‐and‐state faults, one with a weaker patch and the other with rheological transition from steady state velocity‐weakening to velocity‐strengthening friction, we simulate several scenarios of spontaneous earthquake nucleation plausible for natural faults, investigate their response to static shear stress steps, and infer the corresponding aftershock rates. Overall, nucleation processes at weaker patches behave similarly to theories based on spring‐slider models, with some notable deviations. In particular, nucleation and aftershock rates are affected by normal stress heterogeneity in the nucleation zone. Nucleation processes at rheological transitions behave differently, producing complex slip velocity histories, nonmonotonic responses to static stress changes, and aftershock rates with pronounced peaks and seismic quiescence. For such processes, positive stress steps sometimes delay nucleation of seismic events by inducing aseismic transients that relieve stress and postpone seismic slip. Superposition of the complex aftershock response for spatially variable stress changes results in Omori's law for a period of time followed by seismic quiescence. Such behavior was observed at the base of the seismogenic zone near the 1984 Morgan Hill earthquake. We show that the computed aftershock rates are linked to unperturbed slip velocity evolution in the nucleation zone and construct simplified analytical scenarios that explain some features of the response. The qualitative differences that we find between the two nucleation models indicate that aftershock response of rate‐and‐state faults to static stress changes would depend on the conditions under which nucleation occurs on natural faults and may be different from predictions based on spring‐slider models.
Postseismic signature of the 2004 Sumatra earthquake on low‐degree gravity harmonics
Authors: Cannelli V. , Melini D. , Piersanti A. , Boschi E.
Published: December 2008

We perform an extensive analysis of the low‐degree gravity field harmonics measured by the GRACE mission, in order to find a signature of the postseismic relaxation following the 2004 Sumatra earthquake. We find a statistically significant perturbation in the secular trend of low‐degree zonal coefficients (Jl) in correspondence of the 2004 Sumatra earthquake and a similar perturbation, but with weak associated statistical significance, also in the nonzonal coefficients. Technical features and results of such analysis are discussed. The time‐dependent postseismic evolution of harmonic coefficients is modeled for various asthenosphere viscosity values, using a theoretical model of global postseismic deformation. The observed change in secular trend is found to be consistent with our modeling results but it cannot be used to discriminate between viscosities. A forward modeling of the perturbations to time‐dependent zonal variation rates following the Sumatra earthquake for various asthenospheric viscosities is provided. As a result, an evident signature of the Sumatra earthquake on l time series is expected for asthenospheric viscosity values below 1018 Pa s. Therefore, long term l time histories from satellite laser ranging will be able to put constraints on the asthenosphere viscosity, if such a signature is evidenced from data or, at least, put lower limits if no significant perturbation will be observed.
Origin of surface and columnar Indian Ocean Experiment (INDOEX) aerosols using source‐ and region‐tagged emissions transport in a general circulation model
Authors: Verma S. , Venkataraman C. , Boucher O.
Published: December 2008

We study the relative influence of aerosols emitted from different sectors and geographical regions on aerosol loading in south Asia. Sectors contributing aerosol emissions include biofuel and fossil fuel combustion, open biomass burning, and natural sources. Geographical regions include India (the Indo‐Gangetic plain, central India, south India, and northwest India), southeast Asia, east Asia, Africa‐west Asia, and the rest of the world. Simulations of the Indian Ocean Experiment (INDOEX), from January to March 1999, are made in the general circulation model of Laboratoire de Météorologie Dynamique (LMD‐ZT GCM) with emissions tagged by sector and geographical region. Anthropogenic emissions dominate (54–88%) the predicted aerosol optical depth (AOD) over all the receptor regions. Among the anthropogenic sectors, fossil fuel combustion has the largest overall influence on aerosol loading, primarily sulfate, with emissions from India (50–80%) and rest of the world significantly influencing surface concentrations and AOD. Biofuel combustion has a significant influence on both the surface and columnar black carbon (BC) in particular over the Indian subcontinent and Bay of Bengal with emissions largely from the Indian region (60–80%). Open biomass burning emissions influence organic matter (OM) significantly, and arise largely from Africa‐west Asia. The emissions from Africa‐west Asia affect the carbonaceous aerosols AOD in all receptor regions, with their largest influence (AOD‐BC: 60%; and AOD‐OM: 70%) over the Arabian Sea. Among Indian regions, the Indo‐Gangetic Plain is the largest contributor to anthropogenic surface mass concentrations and AOD over the Bay of Bengal and India. Dust aerosols are contributed mainly through the long‐range transport from Africa‐west Asia over the receptor regions. Overall, the model estimates significant intercontinental incursion of aerosol, for example, BC, OM, and dust from Africa‐west Asia and sulfate from distant regions (rest of the world) into the INDOEX domain.
Rayleigh‐Taylor instability under a shear stress free top boundary condition and its relevance to removal of mantle lithosphere from beneath the Sierra Nevada
Authors: Harig Christopher , Molnar Peter , Houseman Gregory A.
Published: December 2008

The separation of zones of apparent downwelling flow at the ends of the Sierra Nevada suggests a relatively large wavelength (∼500 km) of unstable growth, but Rayleigh‐Taylor instabilities for plausible rheological structures with a fixed top boundary condition require much shorter wavelengths (<100 km) for maximum growth rates. To understand this difference, we analyze analytical solutions and perform numerical 2‐D plane strain experiments for Rayleigh‐Taylor instability of a dense layer overlying a less dense substratum, representing the instability between the mantle lithosphere and the underlying asthenosphere, focusing on the effects of a shear stress free boundary condition at the top. The overall effect of this condition is an enhancement of growth rate factors at long wavelengths, which depends greatly on the exponential viscosity variation with depth of the layer. With large or little variation across the unstable layer, the solutions approximate those with a fixed top boundary condition or for constant viscosity, respectively. An intermediate zone showing the enhanced growth rates includes ratios of layer thickness to viscosity e‐folding length, h/L, of ∼1–8 for Newtonian viscosity and ∼1–4 for nonlinear viscosity. The free top condition is likely applicable to geologic situations where the lower crust is weak. Olivine flow laws and low‐temperature estimates at 35 km depth (255–355°C) place the Sierra Nevada viscosity scaling ratio, h/L, between 5 and 9. Thus longer wavelengths than commonly assumed for Rayleigh‐Taylor instabilities seem permissible when viscosity decreases with depth and the top surface of the layer is only weakly constrained.
Global distribution of atmospheric phosphorus sources, concentrations and deposition rates, and anthropogenic impacts
Authors: Mahowald Natalie , Jickells Timothy D. , Baker Alex R. , Artaxo Paulo , Benitez‐Nelson Claudia R. , Bergametti Gilles , Bond Tami C. , Chen Ying , Cohen David D. , Herut Barak , Kubilay Nilgun , Losno Remi , Luo Chao , Maenhaut Willy , McGee Kenneth A. , Okin Gregory S. , Siefert Ronald L. , Tsukuda Seigen
Published: December 2008

A worldwide compilation of atmospheric total phosphorus (TP) and phosphate (PO4) concentration and deposition flux observations are combined with transport model simulations to derive the global distribution of concentrations and deposition fluxes of TP and PO4. Our results suggest that mineral aerosols are the dominant source of TP on a global scale (82%), with primary biogenic particles (12%) and combustion sources (5%) important in nondusty regions. Globally averaged anthropogenic inputs are estimated to be ∼5 and 15% for TP and PO4, respectively, and may contribute as much as 50% to the deposition over the oligotrophic ocean where productivity may be phosphorus‐limited. There is a net loss of TP from many (but not all) land ecosystems and a net gain of TP by the oceans (560 Gg P a−1). More measurements of atmospheric TP and PO4 will assist in reducing uncertainties in our understanding of the role that atmospheric phosphorus may play in global biogeochemistry.
Simultaneous interplanetary scintillation and Heliospheric Imager observations of a coronal mass ejection
Authors: Dorrian G. D. , Breen A. R. , Brown D. S. , Davies J. A. , Fallows R. A. , Rouillard A. P.
Published: December 2008

We describe simultaneous Interplanetary Scintillation (IPS) and STEREO Heliospheric Imager (HI) observations of a coronal mass ejection (CME) on 16 May 2007. Strong CME signatures were present throughout the IPS observation. The IPS raypath lay within the field‐of‐view of HI‐1 on STEREO‐A and comparison of the observations shows that the IPS measurements came from a region within a faint CME front observed by HI‐1A. This front may represent the merging of two converging CMEs. Plane‐of‐sky velocity estimates based on time‐height plots of the two converging CME structures were 325 kms−1 and 550 kms−1 for the leading and trailing fronts respectively. The plane‐of‐sky velocities determined from IPS ranged from 420 ± 10 kms−1 to 520 ± 20 kms−1. IPS results reveal the presence of micro‐structure within the CME front which may represent interaction between the two separate CME events. This is the first time that it has been possible to interpret IPS observations of small‐scale structure within an interplanetary CME in terms of the global structure of the event.
How unusual is the recent series of warm years?
Authors: Zorita E. , Stocker T. F. , von Storch H.
Published: December 2008

Previous statistical detection methods based partially on climate model simulations indicate that, globally, the observed warming lies very probably outside the natural variations. We use a more simple approach to assess recent warming at different spatial scales without making explicit use of climate simulations. It considers the likelihood that the observed recent clustering of warm record‐breaking mean temperatures at global, regional and local scales may occur by chance in a stationary climate. Under two statistical null‐hypotheses, autoregressive and long‐memory, this probability turns to be very low: for the global records lower than p = 0.001, and even lower for some regional records. The picture for the individual long station records is not as clear, as the number of recent record years is not as large as for the spatially averaged temperatures.
Altered solar wind‐magnetosphere interaction at low Mach numbers: Coronal mass ejections
Authors: Lavraud Benoit , Borovsky Joseph E.
Published: December 2008

We illustrate some fundamental alterations of the solar wind‐magnetosphere interaction that occur during low Mach number solar wind. We first show that low Mach number solar wind conditions are often characteristic of coronal mass ejections (CMEs) and magnetic clouds in particular. We then illustrate the pivotal role of the magnetosheath. This comes from the fact that low Mach number solar wind leads to the formation of a low thermal β magnetosheath downstream of the bow shock. This property influences magnetic forces and currents, in particular, and in turn alters magnetosheath‐magnetosphere coupling. The implications of this unusual regime of interaction have generally been overlooked. Potentially affected phenomena include the following: (1) asymmetric magnetosheath flows (with substantial enhancements), (2) asymmetric magnetopause and magnetotail shapes, (3) changes in the development of the Kelvin‐Helmholtz instability and giant spiral auroral features, (4) variations in the controlling factors of dayside magnetic reconnection, (5) cross polar cap potential saturation and Alfvén wings, and (6) global sawtooth oscillations. Here we examine these phenomena, primarily by use of global magnetohydrodynamic simulations, and discuss the mechanisms that rule such an altered interaction. We emphasize the fact that all these effects tend to occur simultaneously so as to render the solar wind‐magnetosphere interaction drastically different from the more typical high Mach number case. In addition to the more extensively studied inner magnetosphere and magnetotail processes, these effects may have important implications during CME‐driven storms at Earth, as well as at other astronomical bodies such as Mercury.
Solar and geomagnetic trends of equatorial evening and nighttime F region vertical ion drifts
Authors: Oyekola O. S. , Oluwafemi C. O.
Published: December 2008

F region vertical ion drifts were inferred from the evening and nighttime ionosonde data for two magnetic equatorial stations in West Africa: Ouagadougou (geographic: 12°N, 1.5°W; 5.9°N dip) and Ibadan (geographic: 7.9°N, 3.9°E; 6°S dip). We examine and discuss the short‐term patterns of behavior of ionospheric variability over Ouagadougou for 1986–1987 years of low solar activity (F10.7 = 80) and 1988–1989 years of high solar activity (F10.7 = 180) for quiet time, while that of Ibadan is for undisturbed (Kp ≤ 3.0) and disturbed (Kp > 3.0) geomagnetic conditions during the 1958 International Geophysical Year (IGY) period, corresponding to high solar flux conditions (F10.7 = 208). Our results indicate that the evening and nighttime ion drift exhibits strong variations with the phase of the solar cycle but only small variations with geomagnetic activity. The characteristic values of evening prereversal velocity enhancements (PRE) vary between about 2–14 m/s and 12–22 m/s and 17–42 m/s and 18–40 m/s for low and high solar flux, unperturbed and perturbed conditions, in that order. The solar minimum evening reversal times are strongly season dependent, while the morning reversal times are season independent except during December solstice, which occurs earliest. During solar maximum, reversal times near dawn and dusk are essentially season independent except during June solstice season, which occurs late. The average occurrence time (1900 LT) of PRE is strongly independent of solar and magnetic variations apart from June solstice of high solar activity periods.
Inelastic strain distribution and seismic radiation from rupture of a fault kink
Authors: Duan Benchun , Day Steven M.
Published: December 2008

We extend an elastodynamic finite element method to incorporate off‐fault plastic yielding into a dynamic earthquake rupture model. We simulate rupture for models of faults with a kink (a sharp change in fault strike), examining how off‐fault plastic yielding affects rupture propagation, seismic radiation, and near‐fault strain distribution. We find that high‐frequency radiation from a kink can be reduced by strong plastic yielding near the kink. The reduction is significant above several Hz. When rupture propagates around the kink onto a less favorably stressed fault segment, plastic strain tends to localize into bands and lobes. Off‐fault plastic yielding also significantly reduces heterogeneity of residual stresses around the kink following a dynamic event. The calculated plastic strain distribution around the kink and the radiated pulse from the kink are nearly grid independent over the range of element size for which computations are feasible. We also find that plastic strain can sometimes localize spontaneously during rupture along a planar fault, in the absence of a discrete stress concentrator like the kink. In that case, a non‐dimensional parameterT, characterizing the initial proximity of off‐fault material to its yield strength, determines whether plastic strain localizes into discrete bands or is smoothly distributed, with a large value ofTpromoting localization. However, in the cases of spontaneous localization, the details of the shear banding change with numerical element size, indicating that the final plastic strain distribution is influenced by interactions occurring at the shortest numerically resolvable scales. Off‐fault plastic yielding also makes an important contribution to the cohesive zone at the advancing edge of the rupture.
Comparison of results of AOGCMs in the Mediterranean Sea during the 21st century
Authors: Marcos Marta , Tsimplis Michael N.
Published: December 2008

It is important for policy making to downscale the knowledge derived from global models to smaller areas. However, this is a nontrivial task for the Mediterranean Sea, a semienclosed basin connected to the Atlantic Ocean through the Strait of Gibraltar. The outputs of 12 atmosphere‐ocean general circulation models (AOGCMs) in the Mediterranean Sea are used to examine temperature (T), salinity (S), and sea level changes for the 21st century under three different climate scenarios (committed climate change, SRES A1B, and SRES A2). Warming and salinification are predicted to occur in the basin. The T increases are translated into an average thermosteric sea level rise between 3 and 61 cm over the basin. Under A1B and A2 scenarios, thermosteric sea level rise is accelerated. Under the committed climate change scenario the thermosteric sea level, although increasing, is decelerated. In the Mediterranean, S has a large impact in sea level changes, and projections of steric sea level range between −22 and 31 cm. The contribution of future atmospheric pressure changes on sea level in the Mediterranean Sea is a reduction of up to 0.6 cm. The 20th century model runs indicate that low‐frequency variability is smaller than that observed. The spatial patterns of steric sea level change are not consistent among the AOGCMs in the region. Overall, results indicate large uncertainties regarding the combined effects of T and S on future Mediterranean mean sea level changes based on these simulations, with even greater discrepancies on the patterns of change.
Mars and Mercury rotation variations from altimetry crossover data: Feasibility study
Authors: Rosat S. , Rosenblatt P. , Trinh A. , Dehant V.
Published: December 2008

Knowledge of the interior structure of terrestrial planets can be achieved by studying the changes of their rotation and orientation in time. We simulate the use of time deviations of altimetry crossover positions to infer information on the nutations of Mars and on the librations of Mercury. The analysis is based on the least squares estimator and uses simulated crossover points. The simulations demonstrate that the use of crossover data improves the estimates of the observed libration amplitude and obliquity of Mercury and allows detecting the nutations of Mars.
Hydrology of malaria: Model development and application to a Sahelian village
Authors: Bomblies Arne , Duchemin Jean‐Bernard , Eltahir Elfatih A. B.
Published: December 2008

We present a coupled hydrology and entomology model for the mechanistic simulation of local‐scale response of malaria transmission to hydrological and climatological determinants in semiarid, desert fringe environments. The model is applied to the Sahel village of Banizoumbou, Niger, to predict interannual variability in malaria vector mosquito populations that lead to variations in malaria transmission. Using a high‐resolution, small‐scale distributed hydrology model that incorporates remotely sensed data for land cover and topography, we simulate the formation and persistence of the pools constituting the primary breeding habitat of Anopheles gambiae s.l. mosquitoes, the principal regional malaria vector mosquitoes. An agent‐based mosquito population model is coupled to the distributed hydrology model, with aquatic‐stage and adult‐stage components. Through a dependence of aquatic‐stage mosquito development and adult emergence on pool persistence, we model small‐scale hydrology as a dominant control of mosquito abundance. For each individual adult mosquito, the model tracks attributes relevant to population dynamics and malaria transmission, which are updated as mosquitoes interact with their environment, humans, and animals. Weekly field observations were made in 2005 and 2006. A 16% increase in rainfall between the two years was accompanied by a 132% increase in mosquito abundance between 2005 and 2006. The model reproduces mosquito population variability at seasonal and interannual timescales and highlights individual pool persistence as a dominant control. Future developments of the presented model can be used in the evaluation of impacts of climate change on malaria, as well as the a priori evaluation of environmental management‐based interventions.
Expression of Green Fluorescence Protein (GFP) in Zebrafish Muscle through Injection: A Gene Therapy Model
Authors: Lin C. S. , Shih Jhen Ru , Hsu C. H. , Wen Z.H. , Chakraborty Chiranjib
Published: December 2008

Expression of the target gene is important for gene therapy. Presently, localized transgenesis is used for gene therapy which can be achieved by a target gene expression. Here, we have reported the plasmid mediated gene therapy to zebrafish model. For this purpose, we have chosen green fluorescent protein (GFP) as a target gene because the expression can be detected easily. GFP was inserted in a plasmid vector, pQE30 to develop the vector pQE30GFP. The plasmid pQE30GFP was constructed form plasmid, pQE30 and pEGFPC2. pQE30GFP injected directly in one group of fish into the muscle where luciferase expression was noted. In another group, after injection electroporation was performed where we have also noted luciferase expression; but, electroporation cause muscle injury to the zebrafish. In our case, the expression was very strong at the site of injection in first group in compare to electroporation group and in both the cases expression was stable more than two weeks.
Cross-Cultural (mis)Communication in IS Offshoring: Understanding through Conversation Analysis
Authors: Avison David , Banks Peter
Published: December 2008

The offshoring of information systems (IS) work has seen phenomenal growth in the past 5 or more years. This has resulted in IS professionals, interacting with workers from vastly different cultural backgrounds, in order to deliver IS project and support services. This cultural ‘barrier’ has been highlighted in the IS literature as a key challenge for offshoring; however, the attention given to research in the field has in the main been restricted to surveys or interviews, often reliant on reductionist national culture models. Within the fields of linguistics and anthropology, the ethnographic research technique of conversation analysis (CA) has been successfully applied to cross-cultural communications. However, there have been no concerted research efforts to apply CA to IS research in general and to IS offshoring in particular. Our research aims to address that gap by analysing naturally occurring recordings of telephone conferences between offshore vendor staff in India and UK/US employees of a major pharmaceutical company. The research has identified and analysed two important phenomena observed within these communications. Firstly, evidence of asymmetries of participation across cultural divides has been documented, and analysed for underlying causes, such as different attitudes to hierarchy and a lack of shared understanding of expected responses. Secondly, differences in the rhetorical organisation of conversation by participants have also been observed and clearly documented within transcribed specimens of these conversations. These phenomena led to seven findings that are aimed to stimulate further research. Finally, and perhaps most importantly, this paper demonstrates how the methodological approach of CA can be applied to IS offshoring research, producing key insights into culturally loaded conversations with clear applications for practice. We hope that this evidence of the potential of CA in IS research will inspire IS researchers to use the approach in other domains as well as in further work in offshoring situations.
First passage percolation on locally treelike networks. I. Dense random graphs
Authors: Bhamidi Shankar
Published: December 2008

We study various properties of least cost paths under independent and identically distributed (iid) disorder for the complete graph and dense Erdős–Rényi random graphs in the connected phase, with iid exponential and uniform weights on edges. Using a simple heuristic, we compute explicitly limiting distributions for (properly recentered) lengths of shortest paths between typical nodes as well as multiple source destination pairs; we also derive asymptotics for the number of edges on the shortest path, namely, the hopcount, and find that the addition of edge weights converts these graphs from ultrasmall world networks to small world networks. Finally we study the Vickrey–Clarke–Groves measure of overpayment for the complete graph with exponential edge weights and show that the complete graph is far from monopolistic for large n.
Implementation and performance of a domain-specific basis set incremental approach for correlation energies: Applications to hydrocarbons and a glycine oligomer
Authors: Friedrich Joachim , Dolg Michael
Published: December 2008

The fully automated implementation of the incremental scheme for CCSD energies has been modified for the usage of a domain-specific basis set. We find that the computational effort can be reduced significantly without loss of accuracy. It is shown explicitly in applications on hydrocarbons and the (glycine)4 oligomer that the error of the incremental expansion for the total energy is usually below 1 kcal/mol at third order. Furthermore, it is demonstrated that the proposed approach saves CPU time, random access memory, and disk space. Moreover, we show in various tests that the inherently parallel incremental calculations can be run on up to 50 CPUs without significant loss of computer time.
Theory and atomistic simulation of krypton fluid
Authors: Eskandari Nasrabad Afshin
Published: December 2008

An ab initio interaction potential available in literature is scaled via an empirical procedure and used in an extensive computer simulation study to investigate the thermodynamic properties and self-diffusion coefficient of krypton over a wide range of densities and temperatures. The thermodynamic properties of the fluid phase equilibriums are computed utilizing the Gibbs ensemble Monte Carlo simulation technique. The equation of state and the pair correlation function are obtained using the NVT-Monte Carlo simulation method. The time-correlation function formalism of Green–Kubo is applied in molecular dynamics simulations to calculate the self-diffusion coefficient. Furthermore, the modified Cohen–Turnbull theory is employed to determine the self-diffusion coefficient and the mean free volume needed for this purpose is provided via the generic van der Waals theory. The virial minimization method is used to compute the effective diameter and the results are applied within the generic van der Waals theory as the repulsion-attraction splitting distance of the interaction potential. A remarkable agreement is observed between the computed and empirical results for the orthobaric densities, the vapor pressure, the critical point, and the equation of state. A detailed analysis is presented for the calculated self-diffusion coefficient.
Osmotic pressure acting on a semipermeable shell immersed in a solution of polyions
Authors: Tsekov Roumen , Stukan Mikhail R. , Vinogradova Olga I.
Published: December 2008

We study theoretically the osmotic equilibria for a shell immersed in a suspension of polyions (e.g., colloids, polyelectrolytes, etc.). The shell is treated as impermeable for polyions, but allowing free diffusion of counterions that permeate inside the shell. From the solution of linearized Poisson–Boltzmann equation, we obtain the distribution of a potential and concentration profiles for polyions and counterions. We then obtain an explicit formula for the excess osmotic pressure of a polyion solution exerted on the shell, which includes a quadratic term in order to provide a self-consistency of a linear theory. As a result this pressure is larger than given by a concentration of polyions at the outer shell boundary obtained within linearized theory. It is, however, always smaller than or equal to the bulk osmotic pressure. This difference is attributed to a repulsive electrostatic disjoining pressure due to an overlap of counterion clouds inside the shell. A comparison with molecular dynamics simulations is provided and demonstrates that although the concentration profiles obtained within a linear theory deviate from simulation data at large potential, the theoretical and simulation pressures are in surprisingly good harmony.
Dynamical simulations of charged soliton transport in conjugated polymers with the inclusion of electron-electron interactions
Authors: Ma Haibo , Schollwöck Ulrich
Published: December 2008

We present numerical studies of the transport dynamics of a charged soliton in conjugated polymers under the influence of an external time-dependent electric field. All relevant electron-phonon and electron-electron interactions are nearly fully taken into account by simulating the monomer displacements with classical molecular dynamics and evolving the wave function for the π electrons by virtue of the adaptive time-dependent density matrix renormalization group simultaneously and nonadiabatically. It is found that after a smooth turn on of the external electric field the charged soliton is accelerated at first up to a stationary constant velocity as one entity consisting of both the charge and the lattice deformation. An Ohmic region (6 mV/Å≤E0≤12 mV/Å) where the stationary velocity increases linearly with the electric field strength is observed. The relationship between electron-electron interactions and charged soliton transport is also investigated in detail. We find that the dependence of the stationary velocity of a charged soliton on the on-site Coulomb interactions U and the nearest-neighbor interactions V is due to the extent of delocalization of the charged soliton defect.
Shallow donor states induced in ZnSe:Au single crystals by lattice deformation
Authors: Nedeoglo N. D. , Nedeoglo D. D. , Sirkeli V. P. , Tiginyanu I. M. , Laiho R. , Lähderanta E.
Published: December 2008

Photoluminescence (PL) spectra are investigated in n-ZnSe single crystals at different temperatures from 4.4 to 300 K immediately after doping with Au from melt of Se+Au or Zn+Au and after storage of the doped samples for 4 years in the dark under normal room conditions. Due to the formation of Aui interstitial donors in the n-ZnSe:Se:Au crystals with time, the origin of the near band edge PL changes from acceptor-bound to donor-bound excitons. Taking into account the results of PL characterization, we proposed that the Aui donors are generated by displacement of Au ions from regular lattice sites to interstitial sites with the help of lattice deformation forces. Transport measurements show dramatic increase in the electrical conductivity and the free electron concentration after storage of the n-ZnSe:Zn:Au crystals, thus confirming the proposed model.