bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of nongeminate recombination on the performance of pristine and annealed P3HT:PCBM solar cells
Authors: Gluecker Markus , Foertig Alexander , Dyakonov Vladimir , Deibel Carsten
Published: July 2012

Transient photovoltage (TPV) and voltage dependent charge extraction (CE) measurements were applied to poly(3‐hexyl‐thiophene) (P3HT):[6,6]‐phenyl‐C61 butyric acid methyl ester (PCBM) bulk heterojunction solar cells to analyze the limitations of solar cell performance in pristine and annealed devices. From the determined charge carrier decay rate under open circuit conditions and the voltage dependent charge carrier densities n (V), the nongeminate loss current jloss of the device is accessible. We found that jloss alone is sufficient to describe the j –V characteristics across the whole operational range, for annealed and, not yet shown before, also for the lower performing pristine solar cells. Even in a temperature range from 300 K to 200 K nongeminate recombination is found to be the dominant and, therefore, performance limiting loss process. Consequently, charge photogeneration is voltage independent in the voltage range studied. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the mechanism of potential‐induced degradation in crystalline silicon solar cells
Authors: Bauer J. , Naumann V. , Großer S. , Hagendorf C. , Schütze M. , Breitenstein O.
Published: July 2012

Multicrystalline standard p‐type silicon solar cells, which undergo a potential induced degradation, are investigated by different methods to reveal the cause of the degradation. Microscopic local ohmic shunts are detected by electron‐beam‐induced current measurements, which correlate with the sodium distribution in the nitride layer close to the Si surface imaged by time‐of‐flight secondary ion mass spectroscopy. The results are compatible with a model of the formation of a charge double layer on or in the nitride, which inverts the emitter. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Computational study of tautomerism and aromaticity in mono‐ and dithio‐substituted tropolone
Authors: Paine S. W. , Salam A.
Published: July 2012

Keto‐enol tautomerism in mono‐ and dithio‐substituted analogs of tropolone was investigated using electronic structure computations. Seven structural isomers of C7H6OS and four of C7H6S2 were optimized fully in gas phase at HF and B3LYP theoretical levels in combination with the 6‐311++g** basis set, as well as with the CBS‐QB3 and G3 methods. To examine the effects of an aqueous solvent on tautomeric equilibrium constants, each species was optimized in water using the self‐consistent reaction field polarizable continuum model at HF/6‐311++g** and B3LYP/6‐311++g** model chemistries. In both phases it was found that the enol forms were significantly more stable with respect to electronic energy and Gibbs free energy compared to the keto isomers, and outnumbered the keto species by several orders of magnitude. This was understood on the basis of elementary Hückel theory and the 4n + 2 rule, and supported by nucleus independent chemical shifts computations of NMR chemical shifts in these seven membered cyclic systems. © 2012 Wiley Periodicals, Inc.
Determination of hazardous volatile organic compounds in the Hoffmann list by ion‐molecule reaction mass spectrometry
Authors: Wang Haoyang , Xie Wenyan , Chen Min , Liu Baizhan , Guo Yinlong
Published: July 2012

RATIONALE

Off‐line gas or liquid chromatographic mass spectrometry techniques are the most widely used method for analysis of hazardous, carcinogenic volatile organic compounds (VOCs) in mainstream cigarette smoke. However, these conventional techniques can lead to modification of VOCs during sample preparation due to the high reactivity of VOCs. Thus, the development of on‐line mass spectrometric methods for analysis of VOCs is desirable to circumvent this problem.

METHODS

The accurate identification of VOCs is a critical step in the analysis of cigarette smoke. Here, we use ion‐molecule reaction mass spectrometry (IMR‐MS) to study the behavior of standard VOCs in the Hoffmann list during this analytical procedure, and then to profile the VOCs in mainstream cigarette smoke using this on‐line mass spectrometric method.

RESULTS

We first discuss and summarize the charge transfer (CT) ionization and further fragmentation of 20 standard VOCs in the Hoffmann list with the ion reagents Hg+, Xe+, and Kr+. The IMR‐MS instrument was then connected to a Borgwaldt‐RM20H rotary smoking machine in order to study VOCs in mainstream cigarette smoke on‐line. Using this procedure, more than 20 VOCs were identified by IMR‐MS by comparison with experimental results obtained on standard VOCs.

CONCLUSIONS

The IMR‐MS technique can potentially result in reduced molecular fragmentation during analysis of VOCs. However, significant fragmentation still occurs during IMR‐MS when the ionization energy (IE) of the ion reagent is much higher than the IE of the VOC, given that excess energy is stored in the newly formed ion during CT ionization. Given that IMR‐MS cannot distinguish between isobaric compounds or isomers, we summarize the possible overlapping mass peaks from these isobaric species that may be present in analyses of VOCs. Selection of the ion reagent for IMR‐MS should be based on the need to ensure CT ionization of the analytes, as well as avoiding their severe fragmentation. Copyright © 2012 John Wiley & Sons, Ltd.
Prevalence of cases of Mycoplasma hominis, Mycoplasma genitalium, Ureaplasma urealyticum and Chlamydia trachomatis in women with no gynecologic complaints
Authors: Christofolini Denise Maria , Leuzzi Luciana , Mafra Fernanda Abani , Rodart Itatiana , Kayaki Erika Azuma , Bianco Bianca , Barbosa Caio Parente
Published: July 2012

Purpose

To evaluate the prevalence of Mycoplasma hominis, Mycoplasma genitalium, Ureaplasma urealyticum, Chlamydia trachomatis, Trichomonas vaginalis and Neisseria gonorrhoeae in women with no gynecologic complaints screened in the Human Reproduction outpatient clinic of Faculdade de Medicina of ABC, Brazil.

Methods

A total of 106 women without gynecologic complaints and in reproductive age were evaluated. DNA was extracted from cells of the genitourinary tract with bacteria for the detection of six types of bacteria by polymerase chain reaction.

Results

We found that 11.3 % of women had infection with M. hominis and 2.83 % for C. trachomatis. The other bacteria investigated occurred in 2.83 % of women. The percentage of infections identified was 15 %.

Conclusion

The data showed a low percentage of women with genitourinary tract bacteria without symptoms. However, these infections can be sexually transmitted, and relate to infertility and other serious illnesses. The identification and treatment of infection in asymptomatic woman can avoid transmission and future genitourinary trait complications.
Regional Structural Change and Resilience
Authors: Lintz Gerd , Wirth Peter , Harfst Jörn
Published: July 2012

The terms “resilience” and “vulnerability” have both acquired prominence in recent academic and political debate. Originating in the natural sciences, they have meanwhile established themselves not only in the social sciences, but also—and more recently—in the areas of economic geography, as well as urban and regional development. Nevertheless, as is the case with many of the issues adopted from the natural sciences, the social sciences have had to struggle to fully capture and conceptualise the theoretical meaning of the terms. The present article will explore the added-value and limits of using the notions of resilience and vulnerability in relation to structural change in old industrial regions. It will also draw on empirical information from a qualitative case study of Lusatian Lakeland, a former lignite mining region in Eastern Germany that is currently being turned into a tourist destination. Research focuses on analysing the sectoral and regional cooperation between various actors in the region. The introduction of the terms resilience and vulnerability in this case study raises some interesting questions about the nature and interpretation of regional development processes that are characterised by a high degree of uncertainty and severe structural change. The research results also highlight the conceptual difficulties these terms present, particularly in the context of structural transformation.
A randomized controlled trial comparing ceftriaxone with cefazolin for antibiotic prophylaxis in abdominal hysterectomy
Authors: Phoolcharoen Natacha , Nilgate Sumanee , Rattanapuntamanee Orapin , Limpongsanurak Sompop , Chaithongwongwatthana Surasith
Published: July 2012

Objective

To compare the effectiveness of ceftriaxone versus cefazolin for the prevention of febrile morbidity and postoperative infections among patients after abdominal hysterectomy.

Methods

In a double‐blind, randomized, controlled trial in Bangkok, Thailand, 320 patients undergoing abdominal hysterectomy between July 2008 and July 2009 were randomly assigned to receive 1 g of either ceftriaxone or cefazolin intravenously in a single dose before surgery. The participants were evaluated for postoperative fever and infection for up to 4 weeks. χ2or Fisher exact tests were used for statistical analysis.

Results

There was no significant difference between the ceftriaxone and cefazolin groups in incidence of febrile morbidity (9.4% versus 11.2%), wound infection (3.8% versus 1.9%), vaginal cuff infection (3.8% versus 1.9%), or urinary tract infection (1.9% versus 1.9%).

Conclusion

There was no difference between the use of single‐dose preoperative ceftriaxone and cefazolin in preventing infectious morbidity among patients undergoing hysterectomy.
Possible mechanism of phthalates‐induced tumorigenesis
Authors: Wang Yu‐Chih , Chen Hung‐Sheng , Long Cheng‐Yu , Tsai Cheng‐Fang , Hsieh Tsung‐Hua , Hsu Chia‐Yi , Tsai Eing‐Mei
Published: July 2012

Phthalates—substances used in the manufacture of plastics—are considered as possible human carcinogens and tumor‐promoting agents. The worldwide annual production of plastics surpassed 300 million tons in 2010. Plastics are an indispensable material in modern society, and many products manufactured from plastics are a boon to public health; however, plastics also pose health risks. Animal studies have indicated that phthalates are carcinogenic, but human epidemiological data confirming this carcinogenicity in humans are limited. The activation of peroxisome proliferator‐activated receptor α (PPARα), which has been observed in rodent carcinogenesis, has not been observed in humans. Here, we review the hypothesis that the aryl hydrocarbon receptor (AhR) and its downstream signaling cascade promote phthalate‐induced tumorigenesis.
The Double Life of Aufret – Revealed
Authors: Gannon Anna
Published: July 2012

The Aufret ring, acquired by the Victoria and Albert Museum in 1871, has long been considered an Anglo-Saxon artefact, its inscription counted as part of the Anglo-Saxon heritage. Because of the similarity between the names Aufret and Alfred, it became associated with this king and with a ‘lost’ ninth-century coin hoard allegedly found with the ring. On the continent, however, the ring sits comfortably in a well-attested corpus of Lombard seal rings of the seventh century. Thanks to some archive archaeology and the identification of a drawing of the ring in a publication of Ludovico Muratori, an eighteenth-century antiquary, the story of the ring can be traced from its retrieval amongst the ruins of a tomb in Bagnoregio in 1726, to its acquisition by an Italian collector, the Marquis Capponi, until his death in 1746. In 1857 the ring was presented to Edmund Waterton, FSA, who eventually sold it to the Victoria and Albert Museum. By tracing the historical background, and demolishing a few misattributions, this paper restores the Aufret ring to its Lombard context.
Role of oxidative stress and apoptosis in the cellular response of murine macrophages uponLeishmaniainfection
Authors: DESCHACHT MAARTJE , VAN ASSCHE TIM , HENDRICKX SARAH , BULT HIDDE , MAES LOUIS , COS PAUL
Published: July 2012

Leishmaniaparasites are able to survive in the macrophage, one of the most hostile environments of the vertebrate host. The present study investigated howLeishmaniainfection influences these host cell defence mechanisms. Macrophages were infected with antimony-susceptible and -resistantLeishmaniastrains. Free radical production inLeishmania-infected macrophages was measured by electron paramagnetic resonance. Apoptosis was detected with fluorescence microscopy using Annexin-V FITC labelling and with Western blotting to detect caspase-3 cleavage. Independent of their drug susceptibility profile or species background, all studiedLeishmaniastrains induced a similar increase in free radical production in macrophages. O2●−production was significantly elevated during phagocytosis of the stationary phase promastigotes. Conversely, NO levels increased later in the infection and none of the strains induced capsase-3 cleavage.Leishmania donovaniinfection led to phosphatidylserine externalization only in RAW 264.7 cells. After an initial burst of O2●−during phagocytosis of promastigotes, amastigotes protect themselves by decreasing the O2●−production to the basal level. An increased NO production was observed 6 h after infection. Finally, induction of cell death is probably not essential in the survival of the parasite within the macrophage.
Neuropsychological function and suicidal behavior: attention control, memory and executive dysfunction in suicide attempt
Authors: Keilp J. G. , Gorlyn M. , Russell M. , Oquendo M. A. , Burke A. K. , Harkavy-Friedman J. , Mann J. J.
Published: July 2012

Background

Executive dysfunction, distinct from other cognitive deficits in depression, has been associated with suicidal behavior. However, this dysfunction is not found consistently across samples.

Method

Medication-free subjects with DSM-IV major depressive episode (major depressive disorder and bipolar type I disorder) and a past history of suicidal behavior (n = 72) were compared to medication-free depressed subjects with no history of suicidal behavior (n = 80) and healthy volunteers (n = 56) on a battery of tests assessing neuropsychological functions typically affected by depression (motor and psychomotor speed, attention, memory) and executive functions reportedly impaired in suicide attempters (abstract/contingent learning, working memory, language fluency, impulse control).

Results

All of the depressed subjects performed worse than healthy volunteers on motor, psychomotor and language fluency tasks. Past suicide attempters, in turn, performed worse than depressed non-attempters on attention and memory/working memory tasks [a computerized Stroop task, the Buschke Selective Reminding Task (SRT), the Benton Visual Retention Test (VRT) and an N-back task] but not on other executive function measures, including a task associated with ventral prefrontal function (Object Alternation). Deficits were not accounted for by current suicidal ideation or the lethality of past attempts. A small subsample of those using a violent method in their most lethal attempt showed a pattern of poor executive performance.

Conclusions

Deficits in specific components of attention control, memory and working memory were associated with suicidal behavior in a sample where non-violent attempt predominated. Broader executive dysfunction in depression may be associated with specific forms of suicidal behavior, rather than suicidal behaviorper se.
Global prevalence of anxiety disorders: a systematic review and meta-regression
Authors: Baxter A. J. , Scott K. M. , Vos T. , Whiteford H. A.
Published: July 2012

Background

The literature describing the global prevalence of anxiety disorders is highly variable. A systematic review and meta-regression were undertaken to estimate the prevalence of anxiety disorders and to identify factors that may influence these estimates. The findings will inform the new Global Burden of Disease study.

Method

A systematic review identified prevalence studies of anxiety disorders published between 1980 and 2009. Electronic databases, reference lists, review articles and monographs were searched and experts then contacted to identify missing studies. Substantive and methodological factors associated with inter-study variability were identified through meta-regression analyses and the global prevalence of anxiety disorders was calculated adjusting for study methodology.

Results

The prevalence of anxiety disorders was obtained from 87 studies across 44 countries. Estimates of current prevalence ranged between 0.9% and 28.3% and past-year prevalence between 2.4% and 29.8%. Substantive factors including gender, age, culture, conflict and economic status, and urbanicity accounted for the greatest proportion of variability. Methodological factors in the final multivariate model (prevalence period, number of disorders and diagnostic instrument) explained an additional 13% of variance between studies. The global current prevalence of anxiety disorders adjusted for methodological differences was 7.3% (4.8–10.9%) and ranged from 5.3% (3.5–8.1%) in African cultures to 10.4% (7.0–15.5%) in Euro/Anglo cultures.

Conclusions

Anxiety disorders are common and the substantive and methodological factors identified here explain much of the variability in prevalence estimates. Specific attention should be paid to cultural differences in responses to survey instruments for anxiety disorders.
Investigation of Flexure Effect on Transfer Alignment Performance
Authors: Pehlivanoğlu A. Güray , Ercan Yücel
Published: July 2012

Transfer Alignment (TA) is the initialisation process of the Inertial Navigation System (INS) of an air-launched weapon before its release by using the data from the aircraft INS. The aim of this paper is to improve the TA performance by taking into account the aircraft flexures deterministically. The developed procedure neither requires captive carry tests for determination of flexures nor increases the size of the problem, and can be used in real-time missions of any type of military aircraft. The procedure is evaluated for the Velocity Match (VM) method as well as the Velocity and Attitude Match (VAM) method, which are applied through a Kalman Filter (KF). Using a short-time Wing-Rock (WR) manoeuvre, the results of both methods are compared to each other for two cases in which either the flexures are taken into account deterministically, or modelled as noise by assuming that they are unknown. Standard deviations of the errors and the Circular Error Probable (CEP) variations have shown that the TA performance of the VAM method can be much improved if aircraft flexures are incorporated deterministically into the method. The improved performance makes possible target of opportunity missions at shorter weapon ranges, and it decreases target strike errors.
The Reduceron reconfigured and re-evaluated
Authors: NAYLOR MATTHEW , RUNCIMAN COLIN
Published: July 2012

A new version of a special-purpose processor for running lazy functional programs is presented. This processor – the Reduceron – exploits parallel memories and dynamic analyses to increase evaluation speed, and is implemented using reconfigurable hardware. Compared to a more conventional functional language implementation targeting a standard RISC processor running on the same reconfigurable hardware, the Reduceron offers a significant improvement in run-time performance.
A spectral order for infinite-dimensional quantum spaces
Authors: MASHBURN JOE
Published: July 2012

In this paper we extend the spectral order of Coecke and Martin to infinite-dimensional quantum states. Many properties present in the finite-dimensional case are preserved, but some of the most important are lost. The order is constructed and its properties analysed. Most of the useful measurements of information content are lost. Shannon entropy is defined on only a part of the model, and that part is not a closed subset of the model. The finite parts of the lattices used by Birkhoff and von Neumann as models for classical and quantum logic appear as subsets of the models for infinite classical and quantum states.
Zum Stand der Psychologischen Diagnostik
Authors: Schmidt-Atzert Lothar , Kersting Martin , Preckel Franzis , Westhoff Karl , Ziegler Matthias
Published: July 2012

Zusammenfassung. Über ein Viertel ihrer Arbeitszeit verbringen praktisch tätige Psychologinnen und Psychologen mit psychologischer Diagnostik (PD), fast ein Zehntel der Ausbildungsinhalte im Studium befassen sich mit diesem Feld. Die PD leistet innerhalb der psychologischen Disziplinen einen wesentlichen Beitrag zur Bearbeitung und Lösung anstehender gesellschaftlicher Herausforderungen und der Bedarf nach fundierter PD wächst. Dennoch stehen der PD als universitärem Fach zunehmend weniger Ressourcen zur Verfügung. Dieser Beitrag befasst sich mit dem Stand der PD in universitärer Ausbildung und Forschung sowie mit dem Bezug zwischen Wissenschaft und Praxis. Herausforderungen für die PD werden aufgezeigt und Vorschläge für die weitere Fachentwicklung zur Diskussion gestellt.
Calibration of a distributed flood forecasting model with input uncertainty using a Bayesian framework
Authors: Li Mingliang , Yang Dawen , Chen Jinsong , Hubbard Susan S.
Published: July 2012

In the process of calibrating distributed hydrological models, accounting for input uncertainty is important, yet challenging. In this study, we develop a Bayesian model to estimate parameters associated with a geomorphology‐based hydrological model (GBHM). The GBHM model uses geomorphic characteristics to simplify model structure and physically based methods to represent hydrological processes. We divide the observed discharge into low‐ and high‐flow data, and use the first‐order autoregressive model to describe their temporal dependence. We consider relative errors in rainfall as spatially distributed variables and estimate them jointly with the GBHM parameters. The joint posterior probability distribution is explored using Markov chain Monte Carlo methods, which include Metropolis‐Hastings, delay rejection adaptive Metropolis, and Gibbs sampling methods. We evaluate the Bayesian model using both synthetic and field data sets. The synthetic case study demonstrates that the developed method generally is effective in calibrating GBHM parameters and in estimating their associated uncertainty. The calibration ignoring input errors has lower accuracy and lower reliability compared to the calibration that includes estimation of the input errors, especially under model structure uncertainty. The field case study shows that calibration of GBHM parameters under complex field conditions remains a challenge. Although jointly estimating input errors and GBHM parameters improves the continuous ranked probability score and the consistency of the predictive distribution with the observed data, the improvement is incremental. To better calibrate parameters in a distributed model, such as GBHM here, we need to develop a more complex model and incorporate much more information.
Observed correlation between pulsating aurora and chorus waves at Syowa Station in Antarctica: A case study
Authors: Ozaki Mitsunori , Yagitani Satoshi , Ishizaka Kazumasa , Shiokawa Kazuo , Miyoshi Yoshizumi , Kadokura Akira , Yamagishi Hisao , Kataoka Ryuho , Ieda Akimasa , Ebihara Yusuke , Sato Natsuo , Nagano Isamu
Published: July 2012

A high correlation between a pulsating auroral patch and grouped chorus waves was observed on 17 April 2006 at Syowa Station in Antarctica. The spatial distribution of aurora–chorus correlation coefficients is evaluated in order to determine the source region. A pulsating patch at the highest‐correlation pixel shows a one‐to‐one correspondence with the intensity variation of the grouped chorus waves, consisting of successive rising‐tone elements with a duration and spacing of 2–3 s and 20–30 s, respectively. The generation region of the chorus waves is estimated from the latitude and longitude dependence of the equatorial electron gyrofrequencies using the IGRF geomagnetic field model. The extent of the estimated latitude and longitude is consistent with the spatial distribution of the high‐correlation aurora–chorus region. The time difference between the chorus waves and the scattered electrons is also evaluated to discuss the validity of the source region. It shows that electrons reached the ionosphere sooner than the associated chorus waves by ∼1 s, consistent with the theoretical value for conjugate pulsating aurora generated at the equator. These results support the hypothesis that pulsating aurora is caused by pitch angle scattering of high‐energy electrons by whistler mode chorus waves, via a cyclotron resonance at the equator. These results are the first ground‐based observations of high correlations between a spatially extended aurora and chorus waves.
Variability of phytoplankton light absorption in Canadian Arctic seas
Authors: Brunelle Corinne B. , Larouche Pierre , Gosselin Michel
Published: July 2012

Phytoplankton light absorption spectra (aϕ(λ)) were measured in the Canadian Arctic (i.e., the Amundsen Gulf, Canadian Arctic Archipelago, northern Baffin Bay and the Hudson Bay system) to improve algorithms used in remote‐sensing models of primary production. The absorption by algae, dominated by picophytoplankton (<5 μm), was not the major light absorption factor in the four provinces; the colored dissolved organic matter (CDOM) contributed up to 70% of total light absorption. During the fall, the low total chlorophyll a‐specific aϕ*(443) (aϕ(443)/TChl a) coefficients of the Canadian High Arctic were associated with photoacclimation processes (i.e., the package effect) occurring in light‐limited environments. Low light availability and high proportion of CDOM (absorbing strongly the ultraviolet) seem to allow the growth of phytoplankton with accessory pigments absorbing light at longer wavelengths. The ratio of photoprotective and photosynthetic carotenoids (PPC:PSC) was inversely proportional with the salinity and the cell size, and mostly decreases throughout the Canadian High Arctic during fall. In return, the highest TChla‐specific phytoplankton light absorption coefficients at the blue peak (aϕ*(443)) were observed in the Hudson Bay system from September to October (i.e., fall) as well as in the Amundsen Gulf from May to July (i.e., spring/summer). These results will ultimately allow the accurate monitoring of phytoplankton biomass and productivity evolution that is likely to take place as a result of the fast‐changing Arctic environment.
Extensive MRO CRISM observations of 1.27 μm O2 airglow in Mars polar night and their comparison to MRO MCS temperature profiles and LMD GCM simulations
Authors: Clancy R. Todd , Sandor Brad J. , Wolff Michael J. , Smith Michael D. , Lefèvre Franck , Madeleine Jean‐Baptiste , Forget Francois , Murchie Scott L. , Seelos Frank P. , Seelos Kim D. , Nair Hari A. , Toigo Anthony D. , Humm David , Kass David M. , Kleinböhl Armin , Heavens Nicholas
Published: July 2012

The Martian polar night distribution of 1.27 μm (0–0) band emission from O2 singlet delta [O2(1Δg)] is determined from an extensive set of Mars Reconnaissance Orbiter (MRO) Compact Reconnaissance Imaging Spectral Mapping (CRISM) limb scans observed over a wide range of Mars seasons, high latitudes, local times, and longitudes between 2009 and 2011. This polar nightglow reflects meridional transport and winter polar descent of atomic oxygen produced from CO2 photodissociation. A distinct peak in 1.27 μm nightglow appears prominently over 70–90NS latitudes at 40–60 km altitudes, as retrieved for over 100 vertical profiles of O2(1Δg) 1.27 μm volume emission rates (VER). We also present the first detection of much (×80 ± 20) weaker 1.58 μm (0–1) band emission from Mars O2(1Δg). Co‐located polar night CRISM O2(1Δg) and Mars Climate Sounder (MCS) (McCleese et al., 2008) temperature profiles are compared to the same profiles as simulated by the Laboratoire de Météorologie Dynamique (LMD) general circulation/photochemical model (e.g., Lefèvre et al., 2004). Both standard and interactive aerosol LMD simulations (Madeleine et al., 2011a) underproduce CRISM O2(1Δg) total emission rates by 40%, due to inadequate transport of atomic oxygen to the winter polar emission regions. Incorporation of interactive cloud radiative forcing on the global circulation leads to distinct but insufficient improvements in modeled polar O2(1Δg) and temperatures. The observed and modeled anti‐correlations between temperatures and 1.27μm band VER reflect the temperature dependence of the rate coefficient for O2(1Δg) formation, as provided in Roble (1995).
Volcanic edifice weakening via decarbonation: A self‐limiting process?
Authors: Mollo Silvio , Heap Michael J. , Iezzi Gianluca , Hess Kai‐Uwe , Scarlato Piergiorgio , Dingwell Donald B.
Published: July 2012

The inherent instability of volcanic edifices, and their resultant propensity for catastrophic collapse, is a constant source of volcanic risk. Structural instability of volcanic edifices may be amplified by the presence of carbonate rocks in the sub‐volcanic strata, due to the debilitating response of carbonates to thermally‐induced alteration. Nonetheless, decarbonation reactions (the primary weakening mechanism), may stall when the system becomes buffered by rising levels of a reaction product, carbon dioxide. Such thermodynamic stalling might be inferred to serve to circumvent the weakness of volcanic structures. However, the present study shows that, even when decarbonation is halted, rock physical properties continue to degrade due to thermal microcracking. Furthermore, as a result, the pathways for the escape of carbon dioxide are numerous within a volcanic edifice. Therefore, in the case of an edifice with a sub‐volcanic sedimentary basement, the generation of carbon dioxide via decarbonation is unlikely to hinder its impact on instability, and thus potentially devastating flank collapse.
Assessment of galactic cosmic ray models
Authors: Mrigakshi Alankrita Isha , Matthiä Daniel , Berger Thomas , Reitz Günther , Wimmer‐Schweingruber Robert F.
Published: July 2012

Among several factors involved in the development of a manned space mission concept, the astronauts' health is a major concern that needs to be considered carefully. Galactic cosmic rays (GCRs), which mainly consist of high‐energetic nuclei ranging from hydrogen to iron and beyond, pose a major radiation health risk in long‐term space missions. It is therefore required to assess the radiation exposure of astronauts in order to estimate their radiation risks. This can be done either by performing direct measurements or by making computer based simulations from which the dose can be derived. A necessary prerequisite for an accurate estimation of the exposure using simulations is a reliable description of the GCR spectra. The aim of this work is to compare GCR models and to test their applicability for the exposure assessment of astronauts. To achieve this, commonly used models capable of describing both light and heavy GCR particle spectra were evaluated by investigating the model spectra for various particles over several decades. The updated Badhwar‐O'Neill model published in the year 2010, CREME2009 which uses the International Standard model for GCR, CREME96 and the Burger‐Usoskin model were examined. Hydrogen, helium, oxygen and iron nuclei spectra calculated by the different models are compared with measurements from various high‐altitude balloon and space‐borne experiments. During certain epochs in the last decade, there are large discrepancies between the GCR energy spectra described by the models and the measurements. All the models exhibit weaknesses in describing the increased GCR flux that was observed in 2009–2010.
Statistical model of electron pitch angle diffusion in the outer radiation belt
Authors: Artemyev A. , Agapitov O. , Krasnoselskikh V. , Breuillard H. , Rolland G.
Published: July 2012

We calculated the bounce averaged electron pitch angle diffusion coefficients using the statistical characteristics of lower band chorus activity collected by the Cluster mission from 2001–2009. Nine years of Cluster observations provide the distributions of the θ angle between wave vectors and the background magnetic field; and the distributions of the wave total intensity Bw2 for relatively wide ranges of the magnetic latitude λ, the magnetic local times, and the Kp indices. According to Cluster observations, the probability of observing a larger Bw2 increases with λ and depends upon the magnetic local time and Kp. We compared the obtained results with the diffusion coefficients that were calculated under an assumption of parallel whistler wave propagation with a constant intensity Bw2 = 104 pT2. The last calculations substantially underestimated pitch angle diffusion for the small equatorial pitch angles, αeq, but likely overestimates for αeq > 60°. An important increase in for αeq < 30° can be explained by a large mean value for the θ distribution and by an increase of Bw2 at λ > 15°. We took the probability density distribution of the wave mean amplitude into consideration instead of the averaged value. The obtained distribution of the diffusion coefficients indicated that approximately 20% of the most intense waves can provide the main portion of pitch angle diffusion for the dawn/day sector. For the dusk/night sector, wave intensity was significantly weaker and the relative importance of intense waves was not clearly pronounced.
Climatology of the planetary boundary layer over the continental United States and Europe
Authors: Seidel Dian J. , Zhang Yehui , Beljaars Anton , Golaz Jean‐Christophe , Jacobson Andrew R. , Medeiros Brian
Published: July 2012

Although boundary layer processes are important in climate, weather and air quality, boundary layer climatology has received little attention, partly for lack of observational data sets. We analyze boundary layer climatology over Europe and the continental U.S. using a measure of boundary layer height based on the bulk Richardson number. Seasonal and diurnal variations during 1981–2005 are estimated from radiosonde observations, a reanalysis that assimilates observations, and two contemporary climate models that do not. Data limitations in vertical profiles introduce height uncertainties that can exceed 50% for shallow boundary layers (<1 km) but are generally <20% for deeper boundary layers. Climatological heights are typically <1 km during daytime and <0.5 km at night over both regions. Seasonal patterns for daytime and nighttime differ; daytime heights are larger in summer than winter, but nighttime heights are larger in winter. The four data sets show similar patterns of spatial and seasonal variability but with biases that vary spatially, seasonally, and diurnally. Compared with radiosonde observations, the reanalysis and the climate models produce deeper layers due to difficulty simulating stable conditions. The higher‐time‐resolution reanalysis reveals the diurnal cycle in height, with maxima in the afternoon, and with amplitudes that vary seasonally (larger in summer) and regionally (larger over western U.S. and southern Europe). The lower‐time‐resolution radiosonde data and climate model simulations capture diurnal variations better over Europe than over the U.S., due to differences in local sampling times.
Rise of interdisciplinary research on climate
Authors: Weart Spencer
Published: July 2012

Until the middle of the 20th century, the discipline of climatology was a stagnant field preoccupied with regional statistics. It had little to do with meteorology, which itself was predominantly a craft that paid scant attention to physical theory. The Second World War and Cold War promoted a rapid growth of meteorology, which some practitioners increasingly combined with physical science in hopes of understanding global climate dynamics. However, the dozen or so scientific disciplines that had something to say about climate were largely isolated from one another. In the 1960s and 1970s, worries about climate change helped to push the diverse fields into contact. Scientists interested in climate change kept their identification with different disciplines but developed ways to communicate across the boundaries (for example, in large international projects). Around the turn of the 21st century, the Intergovernmental Panel on Climate Change institutionalized an unprecedented process of exchanges; its reports relied especially on computer modeling, which became a center of fully integrated interdisciplinary cooperation.
Sialin (
SLC17A5
) functions as a nitrate transporter in the plasma membrane
Authors: Qin Lizheng , Liu Xibao , Sun Qifei , Fan Zhipeng , Xia Dengsheng , Ding Gang , Ong Hwei Ling , Adams David , Gahl William A. , Zheng Changyu , Qi Senrong , Jin Luyuan , Zhang Chunmei , Gu Liankun , He Junqi , Deng Dajun , Ambudkar Indu S. , Wang Songlin
Published: July 2012

In vivo recycling of nitrate (NO
3
−
) and nitrite (NO
2
−
) is an important alternative pathway for the generation of nitric oxide (NO) and maintenance of systemic nitrate–nitrite–NO balance. More than 25% of the circulating NO
3
−
is actively removed and secreted by salivary glands. Oral commensal bacteria convert salivary NO
3
−
to NO
2
−
, which enters circulation and leads to NO generation. The transporters for NO
3
−
in salivary glands have not yet been identified. Here we report that sialin (
SLC17A
5
), mutations in which cause Salla disease and infantile sialic acid storage disorder (ISSD), functions as an electrogenic 2NO
3
−
/H
+
cotransporter in the plasma membrane of salivary gland acinar cells. We have identified an extracellular pH-dependent anion current that is carried by NO
3
−
or sialic acid (SA), but not by Br
−
, and is accompanied by intracellular acidification. Both responses were reduced by knockdown of sialin expression and increased by the plasma membrane-targeted sialin mutant (L22A-L23A). Fibroblasts from patients with ISSD displayed reduced SA- and NO
3
−
-induced currents compared with healthy controls. Furthermore, expression of disease-associated sialin mutants in fibroblasts and salivary gland cells suppressed the H
+
-dependent NO
3
−
conductance. Importantly, adenovirus-dependent expression of the sialinH183R mutant in vivo in pig salivary glands decreased NO
3
−
secretion in saliva after intake of a NO
3
−
-rich diet. Taken together, these data demonstrate that sialin mediates nitrate influx into salivary gland and other cell types. We suggest that the 2NO
3
−
/H
+
transport function of sialin in salivary glands can contribute significantly to clearance of serum nitrate, as well as nitrate recycling and physiological nitrite-NO homeostasis.
C-fiber activity-dependent maturation of glycinergic inhibition in the spinal dorsal horn of the postnatal rat
Authors: Koch Stephanie C. , Tochiki Keri K. , Hirschberg Stefan , Fitzgerald Maria
Published: July 2012

Sensory circuits are shaped by experience in early postnatal life and in many brain areas late maturation of inhibition drives activity-dependent development. In the newborn spinal dorsal horn, activity is dominated by inputs from low threshold A fibers, whereas nociceptive C-fiber inputs mature gradually over the first postnatal weeks. How this changing afferent input influences the maturation of dorsal horn inhibition is not known. We show an absence of functional glycinergic inhibition in newborn dorsal horn circuits: Dorsal horn receptive fields and afferent-evoked excitation are initially facilitated by glycinergic activity due, at least in part, to glycinergic disinhibition of GAD67 cells. Glycinergic inhibitory control emerges in the second postnatal week, coinciding with an expression switch from neonatal α
2
homomeric to predominantly mature α
1
/β glycine receptors (GlyRs). We further show that the onset of glycinergic inhibition depends upon the maturation of C-fiber inputs to the dorsal horn: selective block of afferent C fibers in postnatal week 2, using perisciatic injections of the cationic anesthetic QX-314, lidocaine, and capsaicin, delays the maturation of both GlyR subunits and glycinergic inhibition, maintaining dorsal neurons in a neonatal state, where tactile responses are facilitated, rather than inhibited, by glycinergic network activity. Thus, glycine may serve to facilitate tactile A-fiber–mediated information and enhance activity-dependent synaptic strengthening in the immature dorsal horn. This period ceases in the second postnatal week with the maturation of C-fiber spinal input, which triggers postsynaptic changes leading to glycinergic inhibition and only then is balanced excitation and inhibition achieved in dorsal horn sensory circuits.
Maternally recruited Aurora C kinase is more stable than Aurora B to support mouse oocyte maturation and early development
Authors: Schindler Karen , Davydenko Olga , Fram Brianna , Lampson Michael A. , Schultz Richard M.
Published: July 2012

Aurora kinases are highly conserved, essential regulators of cell division. Two Aurora kinase isoforms, A and B (AURKA and AURKB), are expressed ubiquitously in mammals, whereas a third isoform, Aurora C (AURKC), is largely restricted to germ cells. Because AURKC is very similar to AURKB, based on sequence and functional analyses, why germ cells express AURKC is unclear. We report that
Aurkc

−/−

females are subfertile, and that AURKB function declines as development progresses based on increasing severity of cytokinesis failure and arrested embryonic development. Furthermore, we find that neither
Aurkb
nor
Aurkc
is expressed after the one-cell stage, and that AURKC is more stable during maturation than AURKB using fluorescently tagged reporter proteins. In addition,
Aurkc
mRNA is recruited during maturation. Because maturation occurs in the absence of transcription, posttranscriptional regulation of
Aurkc
mRNA, coupled with the greater stability of AURKC protein, provides a means to ensure sufficient Aurora kinase activity, despite loss of AURKB, to support both meiotic and early embryonic cell divisions. These findings suggest a model for the presence of AURKC in oocytes: that AURKC compensates for loss of AURKB through differences in both message recruitment and protein stability.
Recursive utility in a Markov environment with stochastic growth
Authors: Hansen Lars Peter , Scheinkman José A.
Published: July 2012

Recursive utility models that feature investor concerns about the intertemporal composition of risk are used extensively in applied research in macroeconomics and asset pricing. These models represent preferences as the solution to a nonlinear forward-looking difference equation with a terminal condition. In this paper we study infinite-horizon specifications of this difference equation in the context of a Markov environment. We establish a connection between the solution to this equation and to an arguably simpler Perron–Frobenius eigenvalue equation of the type that occurs in the study of large deviations for Markov processes. By exploiting this connection, we establish existence and uniqueness results. Moreover, we explore a substantive link between large deviation bounds for tail events for stochastic consumption growth and preferences induced by recursive utility.
Up-regulation of the mitotic checkpoint component Mad1 causes chromosomal instability and resistance to microtubule poisons
Authors: Ryan Sean D. , Britigan Eric M. C. , Zasadil Lauren M. , Witte Kristen , Audhya Anjon , Roopra Avtar , Weaver Beth A.
Published: July 2012

The mitotic checkpoint is the major cell cycle checkpoint acting during mitosis to prevent aneuploidy and chromosomal instability, which are hallmarks of tumor cells. Reduced expression of the mitotic checkpoint component Mad1 causes aneuploidy and promotes tumors in mice [Iwanaga Y, et al. (2007)Cancer Res67:160–166]. However, the prevalence and consequences of Mad1 overexpression are currently unclear. Here we show that Mad1 is frequently overexpressed in human cancers and that Mad1 up-regulation is a marker of poor prognosis. Overexpression of Mad1 causes aneuploidy and chromosomal instability through weakening mitotic checkpoint signaling caused by mislocalization of the Mad1 binding partner Mad2. Cells overexpressing Mad1 are resistant to microtubule poisons, including currently used chemotherapeutic agents. These results suggest that levels of Mad1 must be tightly regulated to prevent aneuploidy and transformation and that Mad1 up-regulation may promote tumors and cause resistance to current therapies.
Eradication of bacterial persisters with antibiotic-generated hydroxyl radicals
Authors: Grant Sarah Schmidt , Kaufmann Benjamin B. , Chand Nikhilesh S. , Haseley Nathan , Hung Deborah T.
Published: July 2012

During
Mycobacterium tuberculosis
infection, a population of bacteria likely becomes refractory to antibiotic killing in the absence of genotypic resistance, making treatment challenging. We describe an in vitro model capable of yielding a phenotypically antibiotic-tolerant subpopulation of cells, often called persisters, within populations of
Mycobacterium smegmatis
and
M. tuberculosis
. We find that persisters are distinct from the larger antibiotic-susceptible population, as a small drop in dissolved oxygen (DO) saturation (20%) allows for their survival in the face of bactericidal antibiotics. In contrast, if high levels of DO are maintained, all cells succumb, sterilizing the culture. With increasing evidence that bactericidal antibiotics induce cell death through the production of reactive oxygen species (ROS), we hypothesized that the drop in DO decreases the concentration of ROS, thereby facilitating persister survival, and maintenance of high DO yields sufficient ROS to kill persisters. Consistent with this hypothesis, the hydroxyl-radical scavenger thiourea, when added to
M. smegmatis
cultures maintained at high DO levels, rescues the persister population. Conversely, the antibiotic clofazimine, which increases ROS via an NADH-dependent redox cycling pathway, successfully eradicates the persister population. Recent work suggests that environmentally induced antibiotic tolerance of bulk populations may result from enhanced antioxidant capabilities. We now show that the small persister subpopulation within a larger antibiotic-susceptible population also shows differential susceptibility to antibiotic-induced hydroxyl radicals. Furthermore, we show that stimulating ROS production can eradicate persisters, thus providing a potential strategy to managing persistent infections.
Resetting capacity limitations revealed by long-lasting elimination of attentional blink through training
Authors: Choi Hoon , Chang Li-Hung , Shibata Kazuhisa , Sasaki Yuka , Watanabe Takeo
Published: July 2012

As with other cognitive phenomena that are based upon the capacity limitations of visual processing, it is thought that attentional blink (AB) cannot be eliminated, even after extensive training. We report in this paper that just 1 h of specific attentional training can completely eliminate AB, and that this effect is robust enough to persist for a few months after training. Results of subsequent behavioral and functional magnetic resonance imaging (fMRI) experiments indicate that this learning effect is associated with improvements in temporal resolution, which are mainly due to processing in the prefrontal areas. Contrary to prior wisdom, we conclude that capacity limitations can be overcome by short-term training.