bluuebunny/crossref_metadata_2025 huggingface dataset:
MicroRNA Regulation in Extreme Environments: Differential Expression of MicroRNAs in the Intertidal Snail Littorina Littorea During Extended Periods of Freezing and Anoxia
Authors: Biggar Kyle K. , Kornfeld Samantha F. , Maistrovski Yulia , Storey Kenneth B.
Published: October 2012

Several recent studies of vertebrate adaptation to environmental stress have suggested roles for microRNAs (miRNAs) in regulating global suppression of protein synthesis and/or restructuring protein expression patterns. The present study is the first to characterize stress-responsive alterations in the expression of miRNAs during natural freezing or anoxia exposures in an invertebrate species, the intertidal gastropod Littorina littorea. These snails are exposed to anoxia and freezing conditions as their environment constantly fluctuates on both a tidal and seasonal basis. The expression of selected miRNAs that are known to influence the cell cycle, cellular signaling pathways, carbohydrate metabolism and apoptosis was evaluated using RT-PCR. Compared to controls, significant changes in expression were observed for miR-1a-1, miR-34a and miR-29b in hepatopancreas and for miR-1a-1, miR-34a, miR-133a, miR-125b, miR-29b and miR-2a in foot muscle after freezing exposure at −6 °C for 24 h (P  < 0.05). In addition, in response to anoxia stress for 24 h, significant changes in expression were also observed for miR-1a-1, miR-210 and miR-29b in hepatopancreas and for miR-1a-1, miR-34a, miR-133a, miR-29b and miR-2a in foot muscle (P  < 0.05). Moreover, protein expression of Dicer, an enzyme responsible for mature microRNA processing, was increased in foot muscle during freezing and anoxia and in hepatopancreas during freezing. Alterations in expression of these miRNAs in L. littorea tissues may contribute to organismal survival under freezing and anoxia.
Agreement alternations with quantified nominals in Modern Hebrew
Authors: DANON GABI
Published: October 2012

Cross-linguistically, quantified noun phrases (QNPs) trigger one of four agreement patterns: with the quantifier, with the noun, default agreement, or semantic agreement. This paper focuses on agreement alternations in Hebrew, and argues that they follow not from variations in hierarchical structure but from the availability of multiple means of assigning values to the QNP's features. Building upon theindex-concordanalysis of Wechsler & Zlatić (2003) and adapting it to the Minimalist framework, it is argued that certain agreement patterns are the result of the quantifier bearing a set of abstract features that do not match its morphologically-triggered ones. Variations in QNP agreement patterns are then argued to be subject to constraints at the interfaces of syntax with both semantics and morphology. Overall, it is claimed that even apparent cases of non-local agreement with non-nominative NPs do not really pose a counterexample to established models of agreement, and that this supports the view that the system of ϕ-features cannot be simply an unstructured bundle of morphological features.
Modeling and simulations of high-power microwave devices using the CHIPIC code
Authors: ZHOU JUN , LIU D. G. , LIAO C.
Published: October 2012

The CHIPIC code, a fully electromagnetic particle-in-cell (PIC) code for modeling and simulations of high-power microwave (HPM) devices, is introduced in this paper. It consists of a two-dimensional (2D) code and a three-dimensional (3D) code. The 2D code can model and simulate HPM devices with symmetric structure on 2D Cartesian, cylindrical and polar grids, while the 3D code can model and simulate HPM devices on 3D Cartesian and cylindrical grids. The fields are calculated using the finite-difference time-domain scheme, and the particles are described by the PIC scheme. Various types of boundary conditions have also been implemented for different kinds of applications. In addition, the 3D code is specifically designed for high-performance modeling and computing. It uses the message passing interface and the open specifications for multiprocessing (OpenMP) for parallelization. Its parallel design ensures that it is capable of efficiently executing on a variety of architectures. In order to allow efficient use of parallel architectures, it provides automated partitioning and dynamic load balancing. Even though this code is still in development, it has successfully simulated various real-world HPM experimental devices. Simulation results on some typical HPM devices by using the CHIPIC code are given, which agree well with those obtained from some well-known PIC codes. Direction for future work is also presented.
Welfare, Wealth and Poverty in Urban China: TheDibaoand Its Differential Disbursement
Authors: Solinger Dorothy J. , Hu Yiyang
Published: October 2012

In the broader social science literature, most studies of social protection investigate welfare in democracies, and at the national level, and typically assume that welfare is given in order to influence voting. This paper, to the contrary, considers social assistance in authoritarian China at the urban level. Its findings are compatible with an explanation that there are two dissimilar logics influencing the distributional decisions of lower-level administrators. That is, there appear to be two modes of social policy implementation, which vary with the fiscal capacity of a given city, as indicated by its average wage: Wealthier cities seem to prefer to push off the streets those viewed as unsuited to a modern city, therefore allocating a substantial proportion of their social assistance funds to them, in order to entice them to stay at home. On the other hand, poorer places seem to permit such people to work outside, in the hope that they will thus be better able to support themselves, thereby saving the city money. A data set from China's Ministry of Civil Affairs was used.
Local Energy Efficiency Policy Implementation in China: Bridging the Gap between National Priorities and Local Interests
Authors: Kostka Genia , Hobbs William
Published: October 2012

This paper analyses Chinese sub-national governments’ implementation strategies to meet national energy efficiency targets in the 11th Five-Year Plan (2006–2010). Previous research has focused on the ways governance practices and decision-making structures shape implementation outcomes, yet very little attention has been given to what strategies local leaders actually employ to bridge national priorities with local interests. To illustrate how local leaders work politically, this paper highlights specific implementation methods officials use to strengthen formal incentives and create effective informal incentives to comply with energy efficiency mandates. The analysis is drawn from 53 interviews conducted in June and July of 2010 in Shanxi, a major coal-producing and energy-intensive province. Findings suggest that local government leaders conform to national directives by “bundling” the energy efficiency policy with policies of more pressing local importance or by “bundling” their energy efficiency objectives with the interests of groups with significant political influence. Ultimately, sub-national government officials frame policies in ways that give them legitimacy at the local level.
Shifting Boundaries between the State and Society: Village Cadres as New Activists in Collective Petition
Authors: Wang Juan
Published: October 2012

Despite the central government's efforts in reducing fiscal burdens on peasants through fiscal reforms in the early 2000s, collective petitions in rural China remain. Complementary to the arbitrary and weak government explanations of state–society conflict, this article reveals the role of village cadres as activists in collective petition. Drawn from extensive fieldwork, I argue that by reducing local government revenues and recentralizing fiscal autonomy to the county level, central fiscal reforms have unintentionally induced a new force of resistance: village cadres. Being disenfranchised from previous privileges, village cadres are now allies rather than adversaries of peasant petitions. This article advances existing literature on China's contentious politics in two ways. First, it recognizes a new group of activists whose savoir-faire improves peasant knowledge of the state capacity in containing state–society conflict. Second, it proposes a dynamic understanding of contentious politics by highlighting the shifting boundaries between the state and society.
In-Flight Alignment Algorithm Based on ADD2 for Airborne POS
Authors: Fang Jiancheng , Han Xiaoying
Published: October 2012

The Position and Orientation System (POS) is a special Strapdown Inertial Navigation System (SINS)/Global Positioning System (GPS) integrated system, widely employed in airborne remote sensing. In-Flight Alignment (IFA) is an effective way to improve the accuracy and speed of initial alignment for an airborne POS. IFA is normally accomplished with references from the position and velocity of GPS for SINS, so that unstable GPS measurements will result in poor alignment accuracy. To improve alignment accuracy under unstable GPS conditions, an adaptive filtering algorithm of the Second-order Divided Difference filter (DD2) based on adaptive innovation estimation is proposed, which introduces calculated innovation covariance directly into computation of the filter gain matrix. Then, the adaptive DD2 algorithm is used for the IFA of the POS with a large initial heading error. To validate the proposed algorithm, simulations are undertaken, followed by IFA experiments for the prototype of the airborne POS (TX-F30) under a turning manoeuvre in a car-mounted experiment, and under an “8” manoeuvre in-flight. The simulations and experimental results show that the proposed algorithm can reach better alignment accuracy under unknown statistical characteristic of GPS measurement noises.
HIV testing in black Africans living in England
Authors: RICE B. , DELPECH V. , SADLER K. E. , YIN Z. , ELFORD J.
Published: October 2012

We examined the uptake of HIV testing in black Africans living in England before the introduction of national testing guidelines. Analyses were conducted using data from an anonymous self-completed questionnaire linked to oral fluid samples to establish HIV status in black Africans attending community venues in England in 2004. Of 946 participants, 44% had ever been tested for HIV and 29% had been tested in the previous 24 months. Of those with undiagnosed HIV, 45% had previously had a negative HIV test. Almost a third of people tested in the UK had been at general practice. Uptake of HIV testing was not associated with perceived risk of HIV. These findings highlight the need for the implementation of national HIV testing guidelines in the UK, including the promotion of testing in general practice. Regular testing in black Africans living in the UK should be promoted regardless of their HIV test history.
Influenza-associated excess mortality in southern Brazil, 1980–2008
Authors: FREITAS F. T. M. , SOUZA L. R. O. , AZZIZ-BAUMGARTNER E. , CHENG P. Y. , ZHOU H. , WIDDOWSON M. A. , SHAY D. K. , OLIVEIRA W. K. , ARAUJO W. N.
Published: October 2012

In order to estimate influenza-associated excess mortality in southern Brazil, we applied Serfling regression models to monthly mortality data from 1980 to 2008 for pneumonia/influenza- and respiratory/circulatory-coded deaths for all ages and for those aged ⩾60 years. According to viral data, 73·5% of influenza viruses were detected between April and August in southern Brazil. There was no clear influenza season for northern Brazil. In southern Brazil, influenza-associated excess mortality was 1·4/100 000 for all ages and 9·2/100 000 person-years for persons aged ⩾60 years using underlying pneumonia/influenza-coded deaths and 10·0/100 000 for all ages and 86·6/100 000 person-years for persons aged ⩾60 years using underlying respiratory/circulatory-coded deaths. Influenza-associated excess mortality rates for southern Brazil are similar to those published for other countries. Our data support the need for continued influenza surveillance to guide vaccination campaigns to age groups most affected by this virus in Brazil.
A new species of chimaeriform (Chondrichthyes, Holocephali) from the uppermost Cretaceous of the López de Bertodano Formation, Isla Marambio (Seymour Island), Antarctica
Authors: Otero Rodrigo A. , Rubilar-Rogers David , Yury-Yañez Roberto E. , Vargas Alexander O. , Gutstein Carolina S. , Mourgues Francisco Amaro , Robert Emmanuel
Published: October 2012

We describe a new chimaeriform fish, Callorhinchus torresi sp. nov., from the uppermost Cretaceous (late Maastrichtian) of the López de Bertodano Formation, Isla Marambio (Seymour Island), Antarctica. The material shows it is distinct from currently known fossil and extant species of the genus, whereas the outline of the tritors (abrasive surfaces of each dental plate) shows an intermediate morphology between earlier records from the Cenomanian of New Zealand and those from the Eocene of Isla Marambio. This suggests an evolutionary trend in tritor morphology in the lineage leading to modern callorhynchids, during the Late Cretaceous-Palaeogene interval.
Long-term evaluation of endothelial function in Kawasaki disease patients
Authors: Pinto Fátima F. , Laranjo Sérgio , Paramés Filipa , Freitas Isabel , Mota-Carmo Miguel
Published: October 2012

Background

Kawasaki disease is an acute systemic vasculitis. Cardiac complications are frequent and include endothelial dysfunction in patients with coronary anomalies. So far, the presence of endothelial dysfunction in patients with no coronary lesions has not been demonstrated. Peripheral arterial tonometry (Endo-PAT) measures the microvascular function in response to local ischaemia and has been validated in adult population, but its use in children is scarce.

Aim

To evaluate endothelial dysfunction in children as a long-term complication after Kawasaki disease using Endo-PAT.

Methods

We evaluated two groups of subjects: (1) Kawasaki disease patients over 11 years of age, diagnosed for >5 years, with no coronary lesions, or any other risk factors for cardiovascular disease; (2) control group of individuals without cardiovascular risk factors. Patients and controls were clinically accessed. Endo-PAT was performed to determine reactive hyperaemia index and augmentation index.

Results

A total of 35 individuals (21 males, age 21 ± 6 years) were evaluated (group 1: 19; controls: 16). Kawasaki disease patients presented significant lower reactive hyperaemia index (1.68 ± 0.49 versus 2.31 ± 0.53; p = 0.001). Augmentation index was similar in both groups (−10 ± 7 versus −11 ± 5; p > 0.005). Most patients with Kawasaki disease disclosed endothelial dysfunction (68%) compared with only 12% in controls.

Conclusions

Endo-PAT is feasible and reproducible in the child population. Endothelial dysfunction is a frequent long-term complication in patients after Kawasaki disease with normal appearing coronary arteries. However, these results need validation in a larger population.
Patient and practice factors affecting growth of infants with systemic-to-pulmonary shunt
Authors: McCrary Andrew W. , Clabby Martha L. , Mahle William T.
Published: October 2012

Background

On recognising poor growth following neonatal palliation with a systemic-to-pulmonary shunt, we sought to determine how patient- and procedure-related factors impact growth, paying attention to the role of the primary cardiologist in this process.

Methods

In a retrospective review, neonates (133 patients) receiving modified systemic-to-pulmonary artery shunts from 2002 to 2009 were studied and outpatient visits were reviewed. Patients with single- and two-ventricle circulations after shunt takedown were compared using weight-for-age z-score.

Results

Single-ventricle patients had a higher weight-for-age z-score at neonatal surgery than two-ventricle patients (−0.4 ± 1.0 compared with −1.2 ± 0.9, with p < 0.001), but they had a greater drop in the weight-for-age z-score to the first outpatient visit (−1.1 ± 0.7 compared with −0.8 ± 0.7, with p = 0.02). After the first outpatient visit, the weight-for-age z-score was not significantly different between single-ventricle and two-ventricle patients. From multivariate analysis, a lower number of nutritional interventions by cardiologists was significantly associated with poor growth (p = 0.03). Poor growth was not associated with race, use of feeding tube, exclusive formula use, or proximity to surgical centre.

Conclusion

The significant drop in the weight-for-age z-score from neonatal surgery to first outpatient visit suggests that these patients may receive inadequate nutrition. The poorest performers received the least number of outpatient changes to their diet. This finding underscores the critical role of the primary cardiologist in optimising weight gain through adjustments in nutrition.
Resource Utilization in the Emergency Department of a Tertiary Care University-Based Hospital in Tokyo Before and After the 2011 Great East Japan Earthquake and Tsunami
Authors: Shimada Mai , Tanabe Aska , Gunshin Masataka , Riffenburgh Robert H. , Tanen David A.
Published: October 2012

Introduction

The objective of this study was to determine the resource utilization of a tertiary care Japanese emergency department (ED) that was not immediately adjacent to the area of the 2011 Great East Japan earthquake and tsunami.

Methods

A retrospective chart review was performed at a tertiary care university-based urban ED located approximately 290 km from the primary site of destruction secondary to an earthquake measuring 9.0 on the Richter Scale and the resulting tsunami. All patients who presented for a period of twelve days before and twelve days after the disaster were included. Data were collected using preformed data collection sheets, and stored in an Excel file. Abstracted data included gender, time in the ED, intravenous fluid administration, blood transfusion, oxygen, laboratories, electrocardiograms (ECGs), radiographs, ultrasound, diagnoses, surgical and medical referrals, and prescriptions written. Ten percent of the charts were reviewed for accuracy, and an error rate reported. Data were analyzed using 2-tailed t-tests, Fisher's exact tests or rank sum tests. Bonferroni correction was used to adjust P values for multiple comparisons.

Results

Charts for 1193 patients were evaluated. The error rate for the abstracted data was 3.2% (95% CI, 2.4%-4.1%). Six hundred fifty-seven patients (53% male) were evaluated in the ED after the earthquake, representing a 23% increase in patient volume. Mean patient time spent in the ED decreased from 61 minutes to 52 minutes (median decrease from 35 minutes to 32 minutes; P = .005). Laboratory utilization decreased from 51% to 43% (P = .006). The percentage of patients receiving prescriptions increased from 48% to 54% (P = .002). There was no change in the number of patients evaluated for surgical complaints, but there was an increase in the number treated for medical or psychiatric complaints.

Conclusion

There was a significant increase in the number of people utilizing the ED in Tokyo after the Great East Japan earthquake and tsunami. Time spent in the ED was decreased along with laboratory utilization, possibly reflecting decreased patient acuity. This information may help in the allocation of national resources when planning for disasters.

ShimadaM, TanabeA, GunshinM, RiffenburghRH, TanenDA. Resource utilization in the emergency department of a tertiary care university-based hospital in Tokyo before and after the 2011 Great East Japan Earthquake and tsunami. Prehosp Disaster Med. 2012;27(6):1-4.
Environmental innovation and policy harmonization in international oligopoly
Authors: Hattori Keisuke
Published: October 2012

This paper investigates firm incentives for developing environmentally clean technologies in a simple two-country model with international oligopoly and lack of regulatory commitment, and compares the incentives under price and quantity regulations with and without policy cooperation between governments. We examine whether policy coordination (choices of policy instruments or policy harmonization) encourages environmental innovation when firms have strategic innovation incentives that may influence future regulation. In a case where policies are non-cooperatively set by governments, quantity regulations yield a greater static benefit for countries; however, dynamically, price regulations encourage more innovation than quantity regulations when environmental damages are not so large. Under both price and quantity regulation regimes, cooperative policy harmonization necessarily enhances net benefits in each country, whereas it discourages firms' innovation incentives when environmental damages are not so small.
Sample Preparation Induced Artifacts in Cryo-Electron Tomographs
Authors: Plevka Pavel , Battisti Anthony J. , Winkler Dennis C. , Tars Kaspars , Holdaway Heather A. , Bator Carol M. , Rossmann Michael G.
Published: October 2012

We investigated the effects of sample preparation and of the exposure to an electron beam on particles in cryo-electron tomographs. Various virus particles with icosahedral symmetry were examined, allowing a comparison of symmetrically related components that should be identical in structure but might be affected differently by these imaging artifacts. Comparison of tomographic reconstructions with previously determined structures established by an independent method showed that neither freezing nor electron beam exposure produced a significant amount of shrinkage along the z axis (thickness). However, we observed damage to regions of the particles located close to the surface of the vitreous ice.
Role of GIRK channels on the noradrenergic transmission in vivo: an electrophysiological and neurochemical study on GIRK2 mutant mice
Authors: Torrecilla María , Fernández-Aedo Irrintzi , Arrue Aurora , Zumarraga Mercedes , Ugedo Luisa
Published: October 2012

Dysfunctional noradrenergic transmission is related to several neuropsychiatric conditions, such as depression. Nowadays, the role of G protein-coupled inwardly rectifying potassium (GIRK)2 subunit containing GIRK channels controlling neuronal intrinsic excitability in vitro is well known. The aim of this study was to investigate the impact of GIRK2 subunit mutation on the central noradrenergic transmission in vivo. For that purpose, single-unit extracellular activity of locus coeruleus (LC) noradrenergic neurons and brain monoamine levels using the HPLC technique were measured in wild-type and GIRK2 mutant mice. Girk2 gene mutation induced significant differences among genotypes regarding burst activity of LC neurons. In fact, the proportion of neurons displaying burst firing was increased in GIRK2 heterozygous mice as compared to that recorded from wild-type mice. Furthermore, this augmentation was even greater in the homozygous genotype. However, neither the basal firing rate nor the coefficient of variation of LC neurons was different among genotypes. Noradrenaline and serotonin basal levels were altered in the dorsal raphe nucleus from GIRK2 heterozygous and homozygous mice, respectively. Furthermore, noradrenaline levels were increased in LC projecting areas such as the hippocampus and amygdale from homozygous mice, although not in the prefrontal cortex. Finally, potency of clonidine and morphine inhibiting LC activity was reduced in GIRK2 mutant mice, although the efficacy remained unchanged. Altogether, the present study supports the role of GIRK2 subunit-containing GIRK channels on the maintenance of tonic noradrenergic activity in vivo. Electric and neurochemical consequences derived from an altered GIRK2-dependent signalling could facilitate the understanding of the neurobiological basis of pathologies related to a dysfunctional monoaminergic transmission.
Oncologists' perspectives on concurrent palliative care in a National Cancer Institute-designated comprehensive cancer center
Authors: Bakitas Marie , Lyons Kathleen Doyle , Hegel Mark T. , Ahles Tim
Published: October 2012

Objective:

The purpose of this study was to understand oncology clinicians' perspectives about the care of advanced cancer patients following the completion of the ENABLE II (Educate, Nurture, Advise, Before Life Ends) randomized clinical trial (RCT) of a concurrent oncology palliative care model.

Method:

This was a qualitative interview study of 35 oncology clinicians about their approach to patients with advanced cancer and the effect of the ENABLE II RCT.

Results:

Oncologists believed that integrating palliative care at the time of an advanced cancer diagnosis enhanced patient care and complemented their practice. Self-assessment of their practice with advanced cancer patients comprised four themes: (1) treating the whole patient, (2) focusing on quality versus quantity of life, (3) “some patients just want to fight,” and (4) helping with transitions; timing is everything. Five themes comprised oncologists' views on the complementary role of palliative care: (1) “refer early and often,” (2) referral challenges: “Palliative” equals “hospice”; “Heme patients are different,” (3) palliative care as consultants or co-managers, (4) palliative care “shares the load,” and (5) ENABLE II facilitated palliative care integration.

Significance of results:

Oncologists described the RCT as holistic and complementary, and as a significant factor in adopting concurrent care as a standard of care.
Frequency doubling and field‐aligned ion streaming in a long‐period poloidal pulsation
Authors: Sibeck D. G. , Korotova G. , Turner D. L. , Angelopoulos V. , Glaßmeier K.‐H. , McFadden J. P.
Published: October 2012

We reexamine a long‐period (10–18 min) poloidal pulsation observed by THEMIS‐A in the outer dawn magnetosphere from 10:00 to 12:30 UT on 7 November 2007. The interval was originally reported by Korotova et al. (2009). Although the nonlinear compressional plasma and magnetic field perturbations observed by THEMIS‐A during this interval agree well with model predictions for the linear perturbations associated with antisymmetric waves generated by the ballooning‐mirror mode instability, the phase relationships between these perturbations indicates a complex frequency rather than the purely imaginary frequency that theory predicts for the outer dawnside magnetosphere. Variations in the radial plasma velocity confirm that a phase‐locked north/south oscillation in the equatorial line of nodes associated with the ballooning‐mirror mode waves doubles the frequency of the compressional component of the magnetic field during these pulsations. The same velocity and magnetic field perturbations exclude explanations for the frequency doubling in terms of spatial gradients sweeping back and forth across the spacecraft or drift‐bounce resonances. Azimuthal electric fields associated with the pulsations generate field‐aligned anisotropies in the pitch angle distributions that become more prominent with increasing ion energy due to the presence of drift‐shell splitting and radial flux gradients that steepen with increasing energy. Although there was no evidence for drift‐bounce interactions during this event, the role of such events in ion energization in other events and at other locations remains to be evaluated.
Nonparametric methods for drought severity estimation at ungauged sites
Authors: Sadri S. , Burn D. H.
Published: October 2012

The objective in frequency analysis is, given extreme events such as drought severity or duration, to estimate the relationship between that event and the associated return periods at a catchment. Neural networks and other artificial intelligence approaches in function estimation and regression analysis are relatively new techniques in engineering, providing an attractive alternative to traditional statistical models. There are, however, few applications of neural networks and support vector machines in the area of severity quantile estimation for drought frequency analysis. In this paper, we compare three methods for this task: multiple linear regression, radial basis function neural networks, and least squares support vector regression (LS‐SVR). The area selected for this study includes 32 catchments in the Canadian Prairies. From each catchment drought severities are extracted and fitted to a Pearson type III distribution, which act as observed values. For each method‐duration pair, we use a jackknife algorithm to produce estimated values at each site. The results from these three approaches are compared and analyzed, and it is found that LS‐SVR provides the best quantile estimates and extrapolating capacity.
Fluid flow and metasomatic fault weakening in the Moresby Seamount detachment, Woodlark Basin, offshore Papua New Guinea
Authors: Speckbacher Romed , Behrmann Jan H. , Nagel Thorsten J. , Stipp Michael , Mahlke Julia
Published: October 2012

Low‐angle normal faults play a prominent role in discussions about fault strength, as they require significant weakening to remain active at low angles. The submerged Moresby Seamount detachment (MSD) is arguably the best exposed active low‐angle detachment worldwide. We analyzed dredged MSD protoliths, cataclasites and mylonites to investigate deformation mechanisms and fault‐weakening processes. Deformation is accompanied by important syntectonic, fluid‐induced mass transfer, controlling the rheological behavior of the MSD. While the mafic protolith behaves brittlely at the onset of deformation, the metasomatic mineralogical and chemical changes cause a transition to plastic flow as the rock is progressively exhumed. Immobile elements provide a reference frame for total material gains and losses. Si, Ca and K are syntectonically enriched, while Fe, Ti, Mg, and Al are depleted. Mass increase is about 10% in the cataclasites and about 48% in the mylonites. Main mechanism is syntectonic veining, causing enrichment in calcite and quartz, thus making the mylonites capable to flow plastically. Minimum time‐integrated fluid flux is calculated as 3 × 105 m3 m−2, indicating that the MSD is an important fluid conduit. The fluids have a deep crustal source, a bottom water temperature and turbidity anomaly suggests that the hydrothermal system is still active. Syntectonic veining in fault rocks and recent seismic activity both suggest that the MSD is intermittently brittle, implying a brittle‐plastic transition at unusually high temperature and low differential stress. We conclude that fault zone metasomatism is crucial in forming weak detachments at passive margins, and may be a prerequisite for successful crustal breakup.
“Equator Crossing” of Shatsky Rise?: New insights on Shatsky Rise tectonic motion from the downhole magnetic architecture of the uppermost lava sequences at Tamu Massif
Authors: Tominaga Masako , Evans Helen F. , Iturrino Gerardo
Published: October 2012

Shatsky Rise is a Large Igneous Province (LIP) currently located in the northwestern Pacific. New downhole magnetic logging data from Integrated Ocean Drilling Program (IODP) Hole U1347A at Tamu Massif of Shatsky Rise captured the magnetic architecture in the uppermost lava sequence, providing a rare opportunity to investigate a time series of the intra‐plate volcanism in conjunction with the Pacific plate construction history centered at the triple junction. Logging data results indicate that Tamu Massif was formed during normal polarity periods south of the paleoequator and crossed the equator at some point in the M19–M17 period. Combining these new observations with previous interpretations of the massif's tectonic history, a time series of the latitudinal tectonic motion of a LIP and the underlying Pacific plate during the plateau formation is postulated.
Amorphization of quartz by friction: Implication to silica‐gel lubrication of fault surfaces
Authors: Nakamura Yu , Muto Jun , Nagahama Hiroyuki , Shimizu Ichiko , Miura Takashi , Arakawa Ichiro
Published: October 2012

To understand physico‐chemical processes at real contacts (asperities) on fault surfaces, we conducted pin‐on‐disk friction experiments at room temperature, using single crystalline quartz disks and quartz pins. Velocity weakening from friction coefficientμ ∼ 0.6 to 0.4 was observed under apparent normal stresses of 8–19 (18 > 19), when the slip rate was increased from 0.003 to 2.6 m/s. Frictional surfaces revealed ductile deformation of wear materials. The Raman spectra of frictional tracks showed blue shifts and broadening of quartz main bands, and appearance of new peaks at 490–520 and 610 cm−1. All these features are indicative of pressure‐ and strain‐induced amorphization of quartz. The mapping analyses of Fourier transform infrared (FT‐IR) spectroscopy at room dry conditions suggest selective hydration of wear materials. It is possible that the strained Si‐O‐Si bridges in amorphous silica preferentially react with water to form silica‐gel. In natural fault systems, amorphous materials would be produced at real fault contacts and accumulate over the fault surfaces with displacements. Subsequent hydration would lead to significant reduction of fault strength during slip.
Identification of the biogenic compounds responsible for size‐dependent nanoparticle growth
Authors: Winkler Paul M. , Ortega John , Karl Thomas , Cappellin Luca , Friedli Hans R. , Barsanti Kelley , McMurry Peter H. , Smith James N.
Published: October 2012

The probability that freshly nucleated nanoparticles can survive to become cloud condensation nuclei is highly sensitive to particle growth rates. Much of the growth of newly formed ambient nanoparticles can be attributed to oxidized organic vapors originating from biogenic precursor gases. In this study we investigated the chemical composition of size‐selected biogenic nanoparticles in the size range from 10 to 40 nm. Particles were formed in a flow tube reactor by ozonolysis ofα‐pinene and analyzed with a Thermal Desorption Chemical Ionization Mass Spectrometer. While we found similar composition in 10 and 20 nm particles, the relative amounts of individual species varied significantly when compared to 40 nm particles. Smaller particles (10 and 20 nm) were characterized by enhancements in carboxylic acids and larger particles (40 nm) showed higher concentrations of carbonyl‐containing compounds and low molecular weight organic acids. This composition change from smaller to larger size particles reflects a vapor pressure increase of the condensing vapors by 1–2 orders of magnitude indicating that the Kelvin effect plays a decisive role in the growth of biogenic nanoparticles.
The fingerprint of human‐induced changes in the ocean's salinity and temperature fields
Authors: Pierce David W. , Gleckler Peter J. , Barnett Tim P. , Santer Benjamin D. , Durack Paul J.
Published: October 2012

The ocean's salinity field is driven primarily by evaporation, precipitation, and river discharge, all key elements of the Earth's hydrological cycle. Observations show the salinity field has been changing in recent decades. We perform a formal fingerprint‐based detection and attribution analysis of these changes between 1955–2004, 60°S and 60°N, and in the top 700 m of the water column. We find that observed changes are inconsistent with the effects of natural climate variability, either internal to the climate system (such as El Niño and the Pacific Decadal Oscillation) or external (solar fluctuations and volcanic eruptions). However, the observed changes are consistent with the changes expected due to human forcing of the climate system. Joint changes in salinity and temperature yield a stronger signal of human effects on climate than either salinity or temperature alone. When examining individual depth levels, observed salinity changes are unlikely (p < 0.05) to have arisen from natural causes over the top 125 m of the water column, while temperature changes (and joint salinity/temperature changes) are distinct from natural variability over the top 250 m.
Traveling planetary‐scale Rossby waves in the winter stratosphere: The role of tropospheric baroclinic instability
Authors: Domeisen Daniela I. V. , Plumb R. Alan
Published: October 2012

The Southern Hemisphere winter stratosphere exhibits prominent traveling planetary‐scale Rossby waves, which generally are not able to induce Stratospheric Sudden Warmings. A series of runs of a simplified general circulation model is presented, aimed at better understanding the generation of these waves. While the generation of planetary‐scale traveling waves through the interaction of synoptic‐scale waves is observed in a control run, when the model is truncated to permit only waves with zonal wave number 1 or 2, the long waves are found to increase in strength, leading to a considerably more active stratosphere including Sudden Warmings comparable in strength to Northern Hemisphere winter. This finding suggests that the role of tropospheric synoptic eddies is two‐fold: while generating a weak planetary‐scale wave flux into the stratosphere, their main effect is to suppress baroclinic instability of planetary‐scale waves by stabilizing the tropospheric mean state.
Detrainment in deep convection
Authors: Böing S. J. , Siebesma A. P. , Korpershoek J. D. , Jonker H. J. J.
Published: October 2012

This study explores the mechanisms that determine detrainment in deep cumulus convection. A set of 90 high‐resolution Large Eddy Simulations is used to systematically explore the sensitivity of continental deep convection to the relative humidity and stability of the free troposphere. It appears that variations in the mass‐flux profiles are determined by detrainment, rather than entrainment. The detrainment shows a strong dependence on the critical mixing ratio, a dimensionless parameter which describes which mixtures of cloud core and environmental air are positively buoyant. A conceptual approach to the parameterization of detrainment is proposed on the basis of these results.
Satellite detection of orographic gravity‐wave activity in the winter subtropical stratosphere over Australia and Africa
Authors: Eckermann S. D. , Wu D. L.
Published: October 2012

Orographic gravity‐wave (OGW) parameterizations in models produce waves over subtropical mountain ranges in Australia and Africa that propagate into the stratosphere during austral winter and deposit momentum, affecting weather and climate. Satellite sensors have measured stratospheric GWs for over a decade, yet find no evidence of these waves. So are parameterizations failing here? Here we argue that the short wavelengths of subtropical OGWs place them near or below the detection limits of satellite sensors. To test this hypothesis, we reanalyze nine years of stratospheric radiances from the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite during austral winter, applying new averaging techniques to maximize signal‐to‐noise and improve thresholds for OGW detection. Deep climatological enhancements in stratospheric OGW variance over specific mountain ranges in Australia and southern Africa are revealed for the first time, which exhibit temporal and vertical variations consistent with predicted OGW responses to varying background winds.
Ionospheric Joule heating, fast flow channels, and magnetic field line topology for IMF By‐dominant conditions: Observations and comparisons with predicted reconnection jet speeds
Authors: Wilder F. D. , Crowley G. , Eriksson S. , Newell P. T. , Hairston M. R.
Published: October 2012

When the interplanetary magnetic field (IMF) is dawnward or duskward, magnetic merging between the IMF and the geomagnetic field occurs near the cusp on the dayside flanks of the magnetosphere. While these periods are usually considered “quiet,” they can lead to intense localized energy deposition into the dayside ionosphere. We analyze two intervals during the geomagnetic storm on 24 August 2005: one with steady duskward IMF and one with steady dawnward IMF. Using outputs from the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) and data from the Defense Meteorological Satellite Program, we show that intense Joule heating exists on fast ionospheric flow channels which lie on open field lines. In addition, the flow channels on open field lines have large components in the sunward direction and therefore resist the bulk solar wind and magnetosheath flow. We compare observed velocities with predicted reconnection jet speeds using magnetosheath and cusp parameters from an MHD simulation. Results suggest that the fast ionospheric flow corresponds to portions of the reconnection jet populated by low‐density plasma. The importance of ionospheric conductance in determining the ionospheric flow is also discussed.
The sea breeze/land breeze circulation in Los Angeles and its influence on nitryl chloride production in this region
Authors: Wagner N. L. , Riedel T. P. , Roberts J. M. , Thornton J. A. , Angevine W. M. , Williams E. J. , Lerner B. M. , Vlasenko A. , Li S. M. , Dubé W. P. , Coffman D. J. , Bon D. M. , de Gouw J. A. , Kuster W. C. , Gilman J. B. , Brown S. S.
Published: October 2012

The sea breeze/land breeze diurnal circulation within the Los Angeles Basin and adjacent waters transports marine air into the basin during the day and urban air to Santa Monica Bay during the night. Nitryl chloride, ClNO2 is a nocturnal trace gas formed from the heterogeneous reaction of dinitrogen pentaoxide (N2O5) with chloride containing aerosol. Its photolysis after sunrise produces atomic chlorine radicals and regenerates NO2, both of which may increase ozone production. Mixing of the chloride source from marine sea salt with the urban NOx source in Los Angeles provides conditions ideal for the production of ClNO2. This paper presents an analysis using a wind profiler on the coast and measurements of ClNO2 and its precursors made from both ship and aircraft to assess the prevailing meteorological conditions important for ClNO2 production in this region, with a particular focus on the production over water within the land breeze phase of the circulation. A box model is used to calculate an upper limit to the amount of ClNO2 capable of being produced strictly over Santa Monica Bay during the land breeze. On three out of the four nights of ClNO2 measurements in Santa Monica Bay, the ClNO2 exceeds the upper limit calculated using the box model and shows that the majority of the ClNO2 is produced over the city and transported to Santa Monica Bay by the land breeze. This ClNO2 transport suggests the sea breeze more efficiently transports aerosol chloride inland than land breeze transports NOx offshore.
On the nature and extent of optically thin marine low clouds
Authors: Leahy L. V. , Wood R. , Charlson R. J. , Hostetler C. A. , Rogers R. R. , Vaughan M. A. , Winker D. M.
Published: October 2012

Macrophysical properties of optically thin marine low clouds over the nonpolar oceans (60°S–60°N) are measured using 2 years of full‐resolution nighttime data from the Cloud‐Aerosol Lidar with Orthogonal Polarization (CALIOP). Optically thin clouds, defined as the subset of marine low clouds that do not fully attenuate the lidar signal, comprise almost half of the low clouds over the marine domain. Regionally, the fraction of low clouds that are optically thin (fthin,cld) exhibits a strong inverse relationship with the low‐cloud cover, with maxima in the tropical trades (fthin,cld > 0.8) and minima in regions of persistent marine stratocumulus and in midlatitudes (fthin,cld< 0.3). Domain‐wide, a power law fit describes the cloud length distribution, with exponentβ = 2.03 ± 0.06 (±95% confidence interval). On average, the fraction of a cloud that is optically thin decreases from ∼1 for clouds smaller than 2 km to <0.3 for clouds larger than 30 km. This relationship is found to be independent of region, so that geographical variations in the cloud length distribution explain three quarters of the variance in fthin,cld. Comparing collocated trade cumulus observations from CALIOP and the airborne High Spectral Resolution Lidar reveals that clouds with lengths smaller than are resolvable with CALIOP contribute approximately half of the low clouds in the region sampled. A bounded cascade model is constructed to match the observations from the trades. The model shows that the observed optically thin cloud behavior is consistent with a power law scaling of cloud optical depth and suggests that most optically thin clouds only partially fill the CALIOP footprint.
Ensemble Kalman filter data assimilation of Thermal Emission Spectrometer temperature retrievals into a Mars GCM
Authors: Greybush Steven J. , Wilson R. John , Hoffman Ross N. , Hoffman Matthew J. , Miyoshi Takemasa , Ide Kayo , McConnochie Timothy , Kalnay Eugenia
Published: October 2012

Thermal Emission Spectrometer (TES) retrieved temperature profiles are assimilated into the GFDL Mars Global Climate Model (MGCM) using the Local Ensemble Transform Kalman Filter (LETKF) to produce synoptic maps of temperature, winds, and surface pressure and their uncertainties over the course of a Martian year. Short‐term (0.25 sol) forecasts compared to independent observations show reduced root mean square error (to 3–4 K global RMSE for a 30‐sol evaluation period during the northern hemisphere autumn) and bias compared to a free running model. Several enhanced techniques result in further performance gains. A 4D‐LETKF considers observations at their correct hour of occurrence rather than every 6 h. Spatially varying adaptive inflation and varying the dust distribution among ensemble members refine estimates of analysis uncertainty through the ensemble spread. Enhancing dust and water ice aerosol schemes and the application of empirical bias correction using time mean analysis increments help account for model biases. Full‐year experiments using prescribed dust opacities and observed TES dust opacities show that while realistic dust distributions are essential to match observed temperatures with a free run simulation, analyses from data assimilation are more robust with respect to imperfections in aerosol distribution. The data assimilation system described here is being used to generate a new reanalysis of Mars weather and climate, which will have many scientific and engineering applications.
Carbon dioxide exchange rates from short‐ and long‐hydroperiod Everglades freshwater marsh
Authors: Jimenez K. L. , Starr G. , Staudhammer C. L. , Schedlbauer J. L. , Loescher H. W. , Malone S. L. , Oberbauer S. F.
Published: October 2012

Everglades freshwater marshes were once carbon sinks, but human‐driven hydrologic changes have led to uncertainty about the current state of their carbon dynamics. To investigate the effect of hydrology on CO2 exchange, we used eddy covariance measurements for 2 years (2008–2009) in marl (short‐hydroperiod) and peat (long‐hydroperiod) wetlands in Everglades National Park. The importance of site, season, and environmental drivers was evaluated using linear and nonlinear modeling, and a novel method was used to test for temporally lagged patterns in the data. Unexpectedly, the long‐hydroperiod peat marsh was a small CO2 source (19.9 g C m−2 from July to December 2008 and 80.0 g C m−2 in 2009), and at no time over the study period was it a strong sink. Contrary to previous research suggesting high productivity rates from a short‐hydroperiod marsh, we estimated that the marl site was a small CO2 sink in 2008 (net ecosystem exchange [NEE] = −78.8 g C m−2) and was near neutral for carbon balance in 2009. In addition, both sites had relatively low gross ecosystem exchange (GEE) over the 2 years of this study. The two sites showed similar responses for NEE versus air temperature, ecosystem respiration (Reco) versus air temperature, and Reco versus water depth, although the magnitude of the responses differed. We saw small lags (30 min in most cases) between carbon fluxes and environmental drivers. This study is foundational for understanding the carbon balance of these ecosystems prior to implementation of the planned Everglades restoration of historical water flow that will likely alter the future trajectory of the carbon dynamics of the Everglades as a whole.