bluuebunny/crossref_metadata_2025 huggingface dataset:
Buckling of stiffeners for stainless steel trapezoidal sheeting
Authors: Misiek Thomas , Krüger Helmut , Ummenhofer Thomas , Kathage Karsten
Published: December 2010

The calculation of the loadbearing capacity of thin‐walled structures, including trapezoidal sheeting, normally follows the procedures of EN 1993‐1‐3 and similar codes. EN 1993‐1‐4 complements this standard for thin‐walled structures made of stainless steel. Unfortunately, a buckling curve for stiffeners between the plane cross‐section parts of the flanges or the webs is lacking. A finite element analysis was performed in order to obtain a buckling curve for such stiffeners. The finite element model was calibrated based on test results and by recalculating the EN 1993‐1‐3 buckling curve for the stiffeners in trapezoidal sheeting made of non‐alloy structural steel. The results of the research into the loadbearing behaviour of thin‐walled stainless steel trapezoidal sheeting presented here are closing this gap: the proposed addition to the design formulae means it is now possible to carry out a complete calculation of the loadbearing capacity of stainless steel trapezoidal sheeting.
The steel design for the new railway bridge over the River Sado in Portugal
Authors: Reis António , Cremer Jean Marie , Lothaire Alain , Lopes Nuno
Published: December 2010

The new railway crossing over the River Sado at Alcacer do Sal in Portugal required a 2.7 km long bridge, comprising two approach viaducts and a main bridge. Steel‐concrete composite decks were adopted, the approach viaducts having plate girder decks with 45 and 37.5 m spans, and the main bridge three spans of 160 m each with a box girder deck. The main bridge, with a continuous deck over 480 m, consists of three continuous bowstrings with a single plane of hangers on the bridge axis. The main aspects of the bridge concept design are described and the steel design in particular is discussed.
Do export status and export intensity increase firm performance?
Authors: Abor Joshua
Published: December 2010

This study examines the effects of export status and export intensity on the performance of firms in Ghana. Our measures of performance include productivity and profitability. Using the Regional Project on Enterprise Development (RPED) dataset covering the period 1991–2002, the results of this study indicate that export status and export intensity have positive effects on productivity, confirming the learning‐by‐exporting hypothesis. Competition on the international market exposes exporting firms to new technologies, and this has the potential of increasing their productivity. Thus, economic policy initiatives should be directed at encouraging firms to enter the export market. Existing exporters should also be motivated to intensify their exporting efforts by exporting more of their output to foreign markets. © 2011 Wiley Periodicals, Inc.
An exploratory study of organizational politics in Kuwait
Authors: Al‐Tuhaih Salem M. , Van Fleet David D.
Published: December 2010

Because politics is a way of life in organizations, organizational politics has been studied by several scholars over the past 40 years. Few studies, though, have examined organizational politics outside of the United States and Europe. This study is a further step toward closing that gap. In particular, we (1) examined the applicability of the Perceptions of Organizational Politics Scale (POPS) instrument in Kuwait, (2) examined the perceived existence of organizational politics in a public organization in Kuwait, and (3) sought to determine if perceptions of organizational politics seemed to be influenced by the same variables in Kuwait as in Western societies. The study found that the perception of organizational politics is relatively strong and that the POPS instrument was applicable in the Kuwaiti culture and could lead to an expanded understanding of organizational politics. The gender of the respondents, their tenure, and their current positions had some influence on perceptions of organizational politics. © 2011 Wiley Periodicals, Inc.
Systematic Review of Prognostic Factors Related to Overall Survival in Patients with Stage IV Colorectal Cancer and Unresectable Metastases
Authors: Stillwell Andrew P. , Ho Yik‐Hong , Veitch Craig
Published: December 2010

Background

With the improvements in newer chemotherapeutic agents, the role of primary tumour resection in patients with stage IV colorectal cancer is controversial. In many cases primary tumour resection is still favoured as first‐line management. However, a detailed understanding of independent prognostic factors related to survival is necessary before making this decision.

Method

A literature search was conducted using Medline and Embase. Studies that performed multivariate analysis on overall survival of patients with incurable stage IV colorectal cancer were included in this review.

Results

Fourteen retrospective studies involving 3209 patients were included. Clinical variables analysed to consistently have independent prognostic significance for long‐term survival included the patients’ performance status (<2), volume of liver metastases (<50%), nodal stage (N0), disease‐free resection margins, and treatment with chemotherapy and/or primary tumour resection. Cancer antigen (CA) 19‐9, low albumin, elevated ALP levels, apical lymph node involvement, presence of ascites, and postoperative transfusion were each assessed by only one study and found to be independently associated with survival. Factors inconsistently reported to have independent prognostic significance were age, ASA score, preoperative CEA levels, primary tumour location, tumour size and differentiation, peritoneal dissemination, and extrahepatic metastases.

Conclusion

Each patient should be reviewed individually on the basis of the above independent prognostic factors before deciding to resect the primary tumour. Patients with a poor performance status, extensive hepatic metastases, and extensive nodal disease detected preoperatively are less likely to have a survival benefit. Nonsurgical approaches to manage these patients should be given careful consideration.
Unplanned Conversion to Thoracotomy During Video‐Assisted Thoracic Surgery Lobectomy does not Compromise the Surgical Outcome
Authors: Park Joon Suk , Kim Hong Kwan , Choi Yong Soo , Kim Jhingook , Shim Young Mog , Kim Kwhanmien
Published: December 2010

Background

Concerns remain unresolved regarding the safety of unplanned conversion to open thoracotomy during video‐assisted thoracic surgery (VATS) lobectomy. We analyzed both early and late outcomes after thoracotomy conversion from VATS.

Methods

From December 2003 to December 2008, a total of 738 VATS lobectomies were attempted. Among them were 34 unplanned conversions to open thoracotomy. Patient characteristics, operative data, and early and late postoperative outcomes were analyzed retrospectively.

Results

Among the 34 conversion cases, 26 patients had lung cancer and 8 had benign lung disease. The conversion rate was 4.61%. Left and right upper lobectomies were most often associated with unplanned conversions. Conversion was classified into five groups: (1) problems related to anthracofibrosis of hilar lymph nodes in 14 patients; (2) intraoperative vessel or bronchus injury in 11 patients; (3) fused interlobar fissure in 4 patients; (4) oncologic problems, including mediastinal or hilar lymph node metastasis in 2 patients; and (5) vascular anomalies in 3 patients. There was one death due to postoperative pneumonia in a patient with multiple co‐morbidities. Two patients had an episode of pneumonia. The mean hospital stay was 10 days, and the median follow‐up period was 30.0 ± 11.47 months. Three patients with lung cancer developed recurrent disease, all of whom were found to have stage III disease. No cancer‐related death occurred. There was no significant difference in survival or recurrence between patients with conversion and those with successful VATS. However, the operating time and hospital stay were significantly longer in conversion patients.

Conclusions

Our data support the claim that VATS lobectomy can be safely performed with an acceptable conversion rate. Unplanned conversion to open thoracotomy does not appear to compromise the prognosis.
Why do patients with psychosis use cannabis and are they ready to change their use?
Authors: Kolliakou Anna , Joseph Candice , Ismail Khalida , Atakan Zerrin , Murray Robin M.
Published: December 2010

Numerous studies have shown that patients with psychosis are more likely to use illicit drugs than the general population, with cannabis being the most popular. There exists overwhelming evidence that cannabis use can contribute to the onset of schizophrenia and poor outcome in patients with established psychosis. Therefore, understanding why patients use cannabis and whether they are motivated to change their habits is important. The evidence is that patients with psychosis use cannabis for the same reasons the general population does, to ‘get high’, relax and have fun. There is little support for the ‘self‐medication’ hypothesis, while the literature points more towards an ‘alleviation of dysphoria’ model. There is a lack of research reporting on whether psychotic patients are ready to change their use of cannabis, which has obvious implications for identifying which treatment strategies are likely to be effective.
Der „Analytische Test“: Validierung eines neuen eignungsdiagnostischen Instruments zur Erfassung von schlussfolgerndem Denken
Authors: Ostapczuk Martin , Musch Jochen , Lieberei Walter
Published: December 2010

Der zum Zwecke der Personalauswahl entwickelte Analytische Test (AT) dient der Erfassung der Fähigkeit zum induktiven und deduktiven schlussfolgernden Denken bei Bewerbern im oberen Fähigkeitsbereich. Zur Erhöhung der Akzeptanz und zur Verbesserung der augenscheinlichen Validität des Verfahrens sind die Aufgaben des AT semantisch in den Kontext beruflicher Situationen eingekleidet. In sechs Validierungsstudien erwies sich der AT als hoch auswertungsobjektiv und hinreichend schwierig, um auch noch im oberen Fähigkeitsbereich zu differenzieren. Die interne Konsistenz und Retestreliabilität waren ebenso zufriedenstellend wie die konvergente und die diskriminante Validität in Bezug auf Schulnoten, verschiedene Intelligenztests und die Big Five. Berichtet werden auch empirische Belege für die Konstruktvalidität, Akzeptanz und hohe g-Sättigung des AT.
Objektive Erfassung von Job Demands und Decision Latitude sowie Zusammenhänge der Tätigkeitsmerkmale mit Erholungsunfähigkeit
Authors: Gebele Niklas , Morling Katja , Rösler Ulrike , Rau Renate
Published: December 2010

Ziel der vorliegenden Studie war die Beantwortung der Frage, ob sich Zusammenhänge von Job Demands und Decision Latitude ( Karasek, 1979 ) mit Fehlbeanspruchungsfolgen auch zeigen, wenn die Tätigkeitsmerkmale mit objektiven Arbeitsanalysemethoden erfasst werden. Zur Operationalisierung der Tätigkeitsmerkmale wurden theoriebasiert Items des Tätigkeitsbewertungssystems TBS ( Pohlandt et al., 2003 ; Rudolph et al., 1987 ) ausgewählt. Die neu gebildeten Skalen Job Demands-TBS und Decision Latitude-TBS wurden in einer Stichprobe von 397 Erwerbstätigen aus verschiedenen Branchen zur Vorhersage von Erholungsunfähigkeit eingesetzt. Simultane konfirmatorische Faktorenanalysen mit den TBS-Items und den FIT-Items ( Richter et al., 2000 ) wurden berechnet. Hierarchische Regressionsanalysen konnten zeigen, dass hohe objektiv und subjektiv erfasste Job Demands sowie geringe subjektiv erfasste Decision Latitude mit Erholungsunfähigkeit einhergehen. Die Erfassung von Job Demands und Decision Latitude mit dem TBS ermöglicht eine vom subjektiven Erleben des Arbeitsplatzinhabers unabhängige Erfassung der Tätigkeitsmerkmale und die direkte Ableitung von Maßnahmen zur Gestaltung gesundheitsförderlicher Arbeitsbedingungen.
Violent Video Games Prime Both Aggressive and Positive Cognitions
Authors: Bösche Wolfgang
Published: December 2010

Previous studies have shown that violent video games prime aggressive thoughts and concepts. Interestingly, positively valenced test stimuli are rarely used in this field, though they might provide useful information on the nature of the emotional response to virtual violence and its associative structure. According to the General Aggression Model (GAM) and its extensions ( Carnagey, Anderson, & Bushman, 2007 ), normal negative reactions to violence are expected. Alternatively, playing violent video games might be construed as engaging in positively valenced playful fighting behavior. To test the potential of violent video games to prime positive concepts, N = 29 adult males played either a violent or a nonviolent video game for 20 minutes and were subsequently tested in a standard lexical decision task consisting of positive, aggressive, nonaggressive negative, and neutral target words. The data show that the violent video game primed aggressive concepts as expected, but also raised positive concepts, and did so independently of the participants’ history of playing violent video games. Therefore, the results challenge the idea that violent video games inherently stimulate negative concepts only.
Cultivation Effects of a Newspaper on Reality Estimates and Explicit and Implicit Attitudes
Authors: Arendt Florian
Published: December 2010

This paper explores the cultivation effect of a newspaper on its readers’ reality estimates and attitudes. Additionally, the study tries to advance cultivation research by examining implicit attitudes (i.e., automatic affective reactions toward an object). A content analysis of four months of news coverage in one particular newspaper showed that foreigners were overrepresented as offenders and that the newspaper had a negative view of the EU. According to cultivation theory, it is assumed that the more people read a newspaper, the more their reality estimates and attitudes correspond to the most recurrent, stable, and overarching patterns of the newspaper’s content. To test this hypothesis, a total of 453 students participated in a study that used a cross-lagged panel design with two waves and a time-lag of two months. Consistent with the cultivation hypothesis, those who spent more time reading the newspaper were more likely to overestimate the frequency of foreigners as offenders (i.e., first-order cultivation) and had more negative self-reported attitudes toward the EU (i.e., second-order cultivation). Additionally, those who read more of the newspaper showed more negative implicit attitudes toward the EU (i.e., implicit cultivation). The data show evidence of a significant causal influence of newspaper exposure on implicit attitudes, and a marginally significant causal effect on the overestimation of foreigners as offenders and on explicit attitudes toward the EU. The consideration of implicit attitudes as an additional dependent variable could advance cultivation theory and research.
Controlling Presentation Speed, Labels, and Tooltips in Interactive Animations
Authors: Rey Günter Daniel , Diehl Stephan
Published: December 2010

The experiment investigated whether controlling presentation speed as well as labels, which display the names of the currently presented nodes in interactive dynamic graphs, affects comprehension performance. Dynamic graphs are animated graphical representations of nodes and edges representing mathematical structures used to model relations between different objects over time. After being tested on spatial imagination and linguistic thinking, 111 students had to answer twelve multiple choice comprehension questions about six interactive dynamic graphs while working with them. For each question, participants were randomly assigned to one cell of a 2 (with or without a scrollbar to adjust the presentation speed of the visualization) × 2 (with labels displaying all names of the currently presented nodes in the dynamic graphs or with tooltips displaying only one node name if the mouse cursor hovers over this node) factorial design. Scrollbars, which allow adjusting the presentation speed, were rarely used and did not foster learners’ comprehension performance. Labels displaying all names of the currently presented nodes fostered learners’ comprehension performance compared to tooltips. The higher the ability for linguistic thinking of the participants, the more their comprehension performance benefited from labels. These results are consistent with the cognitive-affective theory of learning with media.
Seismic imaging using microseismic events: Results from the San Andreas Fault System at SAFOD
Authors: Reshetnikov A. , Buske S. , Shapiro S. A.
Published: December 2010

We have developed a new passive seismic imaging approach that consists of two steps. First, the hypocenter of the microseismic event is precisely located. Second, this event is treated as a “pseudo‐active” seismic source and the reflections within the recorded wavefield are processed by using a directional migration algorithm in order to construct a high‐resolution image of the illuminated subsurface region. In this paper we demonstrate the application of our approach to a number of microseismic events recorded by a borehole array in the San Andreas Fault Observatory at Depth main hole. Results obtained were high‐resolution 3‐D images of different SE–NW–oriented reflectors related to the San Andreas Fault (SAF) system in the close vicinity of the borehole. To support our approach, we compared our findings with other active and passive seismic images and analyzed the correlation with borehole lithology. We revealed a predominantly satisfactory agreement for both juxtapositions. Furthermore, the stacked image of several microearthquakes provides a spatial characterization of the complex internal structure of the SAF, with much higher resolution than can be obtained from surface seismic reflection data.
New estimates of the inertia tensor and rotation of the triaxial nonrigid Earth
Authors: Chen Wei , Shen WenBin
Published: December 2010

The Earth's rotation is perturbed by mass redistributions and relative motions within the Earth system, as well as by the torques from both the internal Earth and celestial bodies. The present study aims to establish a theory to incorporate all these factors perturbing the rotation state of the triaxial Earth, just like the traditional rotation theory of the axial‐symmetric Earth. First of all, we reestimate the Earth's inertia tensor on the basis of two new gravity models, EIGEN‐GL05C and EGM2008. Then we formulate the dynamic equations and obtain their normal modes for an Earth model with a triaxial anelastic mantle, a triaxial fluid core, and dissipative oceans. The periods of the Chandler wobble and the free core nutation are successfully recovered, being ∼433 and ∼430 mean solar days, respectively. Further, the Liouville equations and their general solutions for that triaxial nonrigid Earth are deduced. The Liouville equations are characterized by the complex frequency‐dependent transfer functions, which incorporate the effects of triaxialities and deformations of both the mantle and the core, as well as the effects of the mantle anelasticity, the equilibrium, and dissipative ocean tides. Complex transfer functions just reflect the fact that decays and phase lags exist in the Earth's response to the periodic forcing. Our theory reduces to the traditional rotation theory of the axial‐symmetric Earth when assuming rotational symmetry of the inertia tensor. Finally, the present theory is applied to the case of atmospheric‐oceanic excitation. The effective atmospheric‐oceanic angular momentum function (AMF)χeff=χeff1+iχeff2for the present theory is compared with the AMFχeffsym=χeff1sym+iχeff2symfor the traditional theory and the observed AMFχobs=χ1obs+iχ2obs; we find that the difference betweenχeffandχeffsymis of a few milliseconds of arc (mas) and can sometimes exceed 10 mas. In addition, spectrum analyses indicate thatχeffis in good agreement withχeffsymand, further, show an increase of coherency withχobsespecially in the low‐frequency band. The obvious advantage ofχeffin the low‐frequency band with respect toχeffsymis the critical support of the present theory. However, still better performance of our theory can be expected if the models of the mantle anelasticity and oceanic dynamics were improved. Thus we conclude that the traditional Earth rotation theory should be revised and upgraded to include the effects of the Earth's triaxiality, the mantle anelasticity, and oceanic dynamics. The theory presented in this study might be more appropriate to describe the rotation of the triaxial Earth (or other triaxial celestial bodies such as Mars), though further studies are needed to incorporate the effects of the solid inner core and other possible influences.
Volcanic ash and SO2 in the 2008 Kasatochi eruption: Retrievals comparison from different IR satellite sensors
Authors: Corradini S. , Merucci L. , Prata A. J. , Piscini A.
Published: December 2010

The Kasatochi 2008 eruption was detected by several infrared satellite sensors including Moderate Resolution Imaging Spectroradiometer (MODIS), Advanced Very High Resolution Radiometer (AVHRR), and Atmospheric Infrared Sounder (AIRS). In this work a comparison between the volcanic cloud SO2 and ash retrievals derived from these instruments has been undertaken. The SO2 retrieval is carried out by using both the 7.3 and 8.7 μm absorption features while ash retrieval exploits the 10–12 μm atmospheric window. A radiative transfer scheme is also used to correct the volcanic ash effect on the 8.7 μm SO2 signature. As test cases, three near‐contemporary images for each sensor, collected during the first days of the eruption, have been analyzed. The results show that the volcanic SO2 and ash are simultaneously present and generally collocated. The MODIS and AVHRR total ash mass loadings are in good agreement and estimated to be about 0.5 Tg, while the AIRS retrievals are slightly lower and equal to about 0.3 Tg. The AIRS and MODIS 7.3 μm SO2 mass loadings are also in good agreement and vary between 0.3 and 1.2 Tg, while the MODIS ash corrected 8.7 μm SO2 masses vary between 0.4 and 2.7 Tg. The mass increase with time confirms the continuous SO2 injection in the atmosphere after the main explosive episodes. Moreover the difference between the 7.3 and 8.7 μm retrievals suggests a vertical stratification of the volcanic cloud. The results also confirm the importance of the ash correction; the corrected 8.7 μm SO2 total masses are less than 30–40% of the uncorrected values.
Observations of atmospheric tides on Mars at the season and latitude of the Phoenix atmospheric entry
Authors: Withers Paul , Catling D. C.
Published: December 2010

We report on the atmospheric structure derived from atmospheric entry of NASA's Phoenix Mars probe using Phoenix Atmospheric Structure Experiment (ASE) data complemented by Mars Climate Sounder (MCS) temperature‐pressure profiles. Oscillations in temperature, caused by thermal tides, have vertical wavelengths of tens of kilometres. Their amplitudes are much larger in individual profiles than in dayside and nightside zonal mean MCS profiles which is inconsistent with sole control by the migrating diurnal tide. In the fixed local time reference frame of dayside MCS observations, temperature varies by >15 K with longitudinal wavenumber 3, which could arise from non‐migrating tides produced by the interaction of surface topography with the migrating diurnal tide.
A half‐century of changes in China's lakes: Global warming or human influence?
Authors: Ma Ronghua , Duan Hongtao , Hu Chuanmin , Feng Xuezhi , Li Ainong , Ju Weimin , Jiang Jiahu , Yang Guishan
Published: December 2010

Lake size is sensitive to both climate change and human activities, and therefore serves as an excellent indicator to assess environmental changes. Using a large volume of various datasets, we provide a first complete picture of changes in China's lakes between 1960s–1980s and 2005–2006. Dramatic changes are found in both lake number and lake size; of these, 243 lakes vanished mainly in the northern provinces (and autonomous regions) and also in some southern provinces while 60 new lakes appeared mainly on the Tibetan Plateau and neighboring provinces. Limited evidence suggested that these geographically unbalanced changes might be associated primarily with climate change in North China and human activities in South China, yet targeted regional studies are required to confirm this preliminary observation.
Large amplitude variations recorded by an on‐fault seismological station during the L'Aquila earthquakes: Evidence for a complex fault‐induced site effect
Authors: Calderoni Giovanna , Rovelli Antonio , Di Giovambattista Rita
Published: December 2010

A station (FAGN) installed on a segment of the fault system that generated the April 2009 L'Aquila earthquakes shows larger ground motions compared to nearby stations. Spectral ratios using 304 earthquakes result in a station amplification significantly varying event by event in the frequency band 1–8 Hz. The resulting pattern of amplitude dependence on causative earthquake location reveals that the strongest (up to a factor of 10) amplifications occur for tightly clustered aftershocks aligned with the fault dip beneath FAGN thus indicating a fault‐guided effect. Fault models are investigated in a grid‐search approach by varying velocity, Q, width and depth of the fault zone. Although the problem solution is not unique and there are strong trade‐offs among the model parameters, constraints from observations yield a deep trapping structure model where the most likely values of velocity reduction, Q and damage zone width are 25%, 20, and 280 m, respectively.
A persistent localized microseismic source near the Kyushu Island, Japan
Authors: Zeng Xiangfang , Ni Sidao
Published: December 2010

Very strong signals with apparent velocity higher than Rayleigh wave velocity are observed on noise correlation functions (NCFs) between seismic stations in East Asia. These signals are present on one‐month NCFs in ten years period with stable arrival times, indicating their persistent and localized nature. The signals are strong in the frequency band of 0.07–0.12Hz, and their amplitudes show inter‐annual but not seasonal variation. Location obtained from two algorithms with GSN and FNET data indicates that the source is situated in Kyushu Island, Japan. After an earthquake is used to account for heterogeneity effects, the location is closer to the Ariake bay but still in the island. The non‐seasonal amplitude variation and the peak frequency of 0.1Hz suggest the signals are probably not generated by oceanic sources. This persistent localized microseismic source needs to be taken into consideration in ambient noise tomography studies in East Asia.
Anisotropy of the Taylor scale and the correlation scale in plasma sheet magnetic field fluctuations as a function of auroral electrojet activity
Authors: Weygand James M. , Matthaeus W. H. , El‐Alaoui M. , Dasso S. , Kivelson M. G.
Published: December 2010

Magnetic field data from the Cluster spacecraft in the magnetospheric plasma sheet are employed to determine the correlation scale and the magnetic Taylor microscale from simultaneous multiple‐point measurements for multiple intervals over a range of mean magnetic field directions for three different levels of geomagnetic activity. We have determined that in the plasma sheet the correlation scale along the mean magnetic field direction decreases from 19,500 ± 2200 to 13,100 ± 700 km as the auroral electrojet activity increases from quiet (<80 nT) to active conditions (>200 nT). The reverse occurs for the correlation scale perpendicular to the magnetic field, which increases from 8200 ± 600 km to 13,000 ± 2100 km as the auroral electrojet activity increases from quiet to active conditions. This variation of the correlation scale with geomagnetic activity may mean either a change in the scale size of the turbulence driver or may mean a change in the predominance of one over another type of turbulence driving mechanism. Unlike the correlation scale, the Taylor scale does not show any clear variation with geomagnetic activity. We find that the Taylor scale is longer parallel to the magnetic field than perpendicular to it for all levels of geomagnetic activity. The correlation and Taylor scales may be used to estimate the effective magnetic Reynolds numbers separately for each angular channel. Reynolds numbers were found to be approximately independent of the angle relative to the mean magnetic field. These results may be useful in magnetohydrodynamic modeling of the magnetosphere and can contribute to our understanding of energetic particle diffusion in the magnetosphere.
Rise and fall of electron temperatures: Ohmic heating of ionospheric electrons from underdense HF radio wave pumping
Authors: Gustavsson B. , Rietveld M. T. , Ivchenko N. V. , Kosch M. J.
Published: December 2010

Here we present electron temperature variations observed with incoherent scatter radar during a European Incoherent Scatter Scientific Association Heating experiment with high‐frequency (HF) radio wave transmission at frequencies above the peak ionospheric critical frequency. The electron temperature increased from 2000 K up to 2800 K during the HF transmission periods. During the experiment both pump frequency and polarization were altered between pump pulses. The observed temperature variation is compared with numerical solutions to the electron energy equation with ohmic heating modeling the effect of the radio wave heating of the plasma. Agreement between observations and model is found to be good.
Wave‐forced motion of submerged single‐stem vegetation
Authors: Mullarney Julia C. , Henderson Stephen M.
Published: December 2010

We derive an analytical model for the wave‐forced movement of single‐stem vegetation and test the model against observed vegetation motion in a natural salt marsh. Solutions for constant diameter and tapered stems are expanded using normal mode solutions to the Euler‐Bernoulli problem for a cantilevered beam. These solutions are compared with motion of water and of the sedge Schoenoplectus americanus observed (using synchronized current meters and video) in a shallow salt marsh (depth < 1 m). Consistent with theory, sedge motion led water motion, with the phase decreasing (from 90 to 0 degrees) with increasing wave frequency. After tuning of a single free parameter (Young's modulus), the theory successfully predicted the transfer function between measured water and stem motion. Formulae predicting frequency‐dependent wave dissipation by flexible vegetation are derived. For the moderately flexible stems observed, the model predicted total dissipation was about 30% of the dissipation for equivalent rigid stems.
Aerosol variability over East Asia as seen by POLDER space‐borne sensors
Authors: Su X. , Goloub P. , Chiapello I. , Chen H. , Ducos F. , Li Z.
Published: December 2010

This paper is devoted to analysis of aerosol distribution and variability over East Asia based on PARASOL/POLDER‐3 aerosol products over land. We first compared POLDER‐3 Aerosol Optical Depth (AOD) with fine mode AOD (particles radius ≤ 0.30 μm) computed from AERONET (Aerosol Robotic Network) inversions over 14 sites. The rather good correlation (R ≈ 0.92) observed over land demonstrates the remarkable sensitivity of POLDER‐3 retrievals to the smaller fraction of fine particles, mostly originating from anthropogenic sources. We analyzed the characteristics and seasonal variation of aerosol distribution over East Asia by considering 4 years of POLDER‐3 Level 2 data (March 2005 to February 2009). Our study shows that the spatial distribution of fine‐mode aerosols over East Asia, as retrieved from POLDER‐3, is highly associated with human activities. Our work also evidenced a strong variability of seasonal fine‐mode AOD patterns with geographical locations. Finally, the interannual variation during 2003–2009 periods of summer fine‐mode AOD over North China, in particular the Beijing City region, was analyzed for the contribution to evaluating the regional impact of emission reduction enforced in Beijing during the 2008 Olympic Summer Games. We found that the summer average of fine‐mode AOD exhibited relatively higher values in 2003, 2007, and 2008. The interannual variation patterns of monthly averaged AOD (June to August) shows that June generally exhibits the strongest variation and varies similarly to July, but differs from August. As a reference point, measured total AOD and fine‐mode AOD computed from AERONET inversions in summer are also discussed for the Beijing City region.
Influence of the Mediterranean Sea on the West African monsoon: Intraseasonal variability in numerical simulations
Authors: Gaetani Marco , Fontaine Bernard , Roucou Pascal , Baldi Marina
Published: December 2010

The influence of May to September sea surface temperature (SST) anomalies in the Mediterranean Sea on the West African monsoon is investigated, analyzing the outputs of numerical sensitivity experiments performed using three atmospheric general circulation models (Action de Recherche Petite Échelle Grande Échelle, European/Hamburg, and University of California, Los Angeles) in the framework of the African Monsoon Multidisciplinary Analysis project. The precipitation and atmospheric dynamics response to the SST forcing is explored, in terms of intraseasonal variability, evaluating the results from the individual models and from the multimodel mean. A positive precipitation response to warmer than average conditions in the Mediterranean Sea is found in the Sudano‐Sahelian belt in August–September. The proposed dynamic mechanism underlying the Mediterranean action on the West African monsoon is based on the modifications produced by the SST forcing in the moisture content in the lower troposphere. A warmer eastern Mediterranean in August–September feeds the lower troposphere with additional moisture, with a consequent reinforcement of northerly moisture transport toward the Sahel. Furthermore, warmer SST is linked to a strengthening of the Saharan heat low and to an enhancement of the moist static energy meridional gradient over West Africa, favoring the northward displacement of the monsoonal front.
Understanding the Sahelian water budget through the isotopic composition of water vapor and precipitation
Authors: Risi Camille , Bony Sandrine , Vimeux Françoise , Frankenberg Christian , Noone David , Worden John
Published: December 2010

The goal of this paper is to investigate the added value of water isotopic measurements to estimate the relative influence of large‐scale dynamics, convection, and land surface recycling on the Sahelian water budget. To this aim, we use isotope data in the lower tropospheric water vapor measured by the SCIAMACHY and TES satellite instruments and in situ precipitation data from the Global Network for Isotopes in Precipitation and collected during the African Monsoon Multidisciplinary Analysis field campaign, together with water‐tagging experiments with the Laboratoire de Météorologie Dynamique general circulation model (LMDZ) fitted with isotopes. We show that some isotopic biases in LMDZ reveal the misrepresentation of dehydrating processes that would be undetected without isotopic measurements. In dry regions, the vapor isotopic composition is primarily controlled by the intensity of the air dehydration. In addition, it may also keep some memory of dehydration pathways that is erased in the humidity distribution, namely the relative contribution of dehydration in the tropical upper troposphere versus midlatitudes. In wet regions, vapor and rain isotope compositions are primarily controlled by changes in convection, through rain reevaporation and through the progressive depletion of the vapor by convective mixing along air mass trajectories. Gradients in vapor isotope composition along air mass trajectories may help estimate continental recycling intensity, provided that we could quantify the effect of convection on the isotopic composition of water vapor.
Densities and temperatures in the Venus mesosphere and lower thermosphere retrieved from SOIR on board Venus Express: Retrieval technique
Authors: Mahieux A. , Vandaele A. C. , Neefs E. , Robert S. , Wilquet V. , Drummond R. , Federova A. , Bertaux J. L.
Published: December 2010

The SOIR instrument, flying on board Venus Express, operates in the infrared spectral domain and uses the solar occultation technique to determine the vertical profiles of several key constituents of the Venus atmosphere. The retrieval algorithm is based on the optimal estimation method, and solves the problem simultaneously on all spectra belonging to one occultation sequence. Vertical profiles of H2O, CO, HCl, and HF, as well as some of their isotopologues, are routinely obtained for altitudes ranging typically from 70 to 120 km, depending on the species and the spectral region recorded. In the case of CO2, a vertical profile from 70 up to 150 km can be obtained by combining different spectral intervals. Rotational temperature is also retrieved directly from the CO2 signature in the spectra. The present paper describes the method used to derive the above mentioned atmospheric quantities and temperature profiles. The method is applied on some retrieval cases illustrating the capabilities of the technique. More examples of results will be presented and discussed in a following companion paper which will focus on the CO2 vertical profiles of the whole data set.
Carbon dioxide supersaturation in peatland waters and its contribution to atmospheric efflux from downstream boreal lakes
Authors: Whitfield C. J. , Seabert T. A. , Aherne J. , Watmough S. A.
Published: December 2010

Carbon fluxes at two boreal peatland‐dominated catchments in northeastern Alberta were investigated through the analysis of fen and lake water chemistry and the measurement of partial pressure of carbon dioxide (pCO2) using headspace gas analysis. All waters had low pH (<5.3) and Gran alkalinity (<2.3 mg L−1), high DOC (>15 mg L−1), and were supersaturated with carbon dioxide (CO2) with respect to the atmosphere (CO2: 1.2–54 times atmospheric). Nonetheless, CO2 concentrations in the study lakes were significantly lower compared with surface water pools in associated fen systems. Average atmospheric flux of CO2 from the two lakes were 0.18 and 0.48 g C m−2 d−1, while potential fluxes from small surficial pools on the fen complexes were an order of magnitude higher. The higher average efflux estimated at one of the lakes (relative to the other) was attributed to shorter lake residence time and smaller relative lake area (i.e., higher relative carbon loading). Carbon mass balances for the lakes suggest that they act as conduits for dissolved CO2 from surrounding fen complexes to the atmosphere. In one of the two study catchments (with negligible groundwater sources), inputs of dissolved CO2 from fen surface waters supported a substantial component (∼30%) of the lake atmospheric CO2 efflux.
Quantitative evaluation of Enterocytozoon bieneusi infection in simian immunodeficiency virus‐infected rhesus monkeys
Authors: Sestak K. , Aye P.P. , Buckholt M. , Mansfield K.G. , Lackner A.A. , Tzipori S.
Published: December 2010

Abstract: The association of the microsporidia Enterocytozoon bieneusi with chronic diarrhea and wasting in individuals with acquired immunodeficiency syndrome (AIDS) has been demonstrated. The disease caused by E. bieneusi has been linked to decreased levels of circulating CD4+ T lymphocytes. In this study, we investigated the relationship between the extent of excretion of E. bieneusi in feces of simian immunodeficiency virus (SIV)‐infected juvenile macaques and the CD4+ T lymphocyte counts in the peripheral blood. Twelve juvenile rhesus monkeys (Macaca mulatta) were intravenously inoculated with the pathogenic molecular clone SIVmac239. Numbers of CD4+ T lymphocytes were assessed by three‐color flow cytometry. The presence of E. bieneusi DNA in feces was assessed by nested PCR. In addition, selected samples of feces were examined by competitive quantitative PCR to assess the level of E. bieneusi infection. Low (n = 5) to undetectable (n = 7) quantities of E. bieneusi were present in feces of the twelve animals in prior to inoculation with SIV. After SIV inoculation the number of animals shedding E. bieneusi increased (n = 10) as did the quantity of E. bieneusi shedding in the feces. Of the twelve juvenile animals, five animals died within 8 months post‐SIV inoculation with symptoms of AIDS. Four of the five deceased animals showed shedding of E. bieneusi DNA in feces (≥100 spores/g) for at least three consecutive months. Increased number of E. bieneusi in feces was accompanied by decreased counts of circulating CD4+ T lymphocytes and increased SIV plasma viral load.
A probabilistic model of plasmid replication regulation by a combination of handcuffing, iteron number and dimerization of RepA protein.
Authors: Watve Milind , Tendulkar Gauri , Ghate Ketaki
Published: December 2010

Plasmids are small circular DNA molecules in bacteria which replicate sharing the replication machinery with the bacterial chromosome. Since plasmids are much smaller than the chromosome, unless their replication is tightly regulated, their copy numbers can escalate quickly. A number of mechanisms of plasmid replication regulation are known in P1 plasmid of E. coli. Mechanisms such as autorepression of the replication initiator protein (RepA) and its dimerization are unable to explain copy number regulation by themselves. The number of RepA binding sites (iterons) is inversely related to copy numbers. Handcuffing of plasmids by RepA dimer is believed to be the main mechanism of arresting replication. We show here with a probabilistic model that for the handcuffing mechanism to work, a certain iteron number is critical without which handcuffing is unlikely to work. Further, RepA autorepression, dimerization, iteron number and handcuffing mechanism need to work in concert and no single mechanism in isolation is able to regulate plasmid replication effectively. The model also makes quantitative predictions that can be tested experimentally.
High Hydrostatic Pressure Food Processing
Authors: Jung Stephanie , Tonello Samson Carole , Lamballerie Marie de
Published: December 2010

The wide variety of commercialized food products using high-pressure processing (HPP) illustrates the versatility of this technology that has evolved from the status of emerging processing to an industrial reliable technology in the past 20 years. The unique effects of pressure on food constituents along with the consumers' acceptance of the process, explain the tremendous potential of this technology for the production of microbiologically safe, nutritional-rich and preservative-free products. While the advantages of the process compensate for the reasonable processing cost (€0.045 /kg to €0.087 /kg, i.e., ∼ US$ 0.066/lb to US$ 0.127/lb depending on the operating conditions at an industrial level), the technology still needs to overcome few drawbacks to pursue its development, and some more mechanistic understanding of HPP effects are yet required. This chapter gives an overview of the effect of this technology on food safety- and shelf life-related microorganisms, food constituents, and quality attributes of treated products. This chapter also addresses the use of this technology as an extraction tool and identifies some of the challenges that the technology still faces. The past, current and upcoming progresses that have been done on the development of industrial-size high pressure equipment, and the current commercial applications are also described.
Biomedical Applications of Synchrotron Infrared Microspectroscopy
Authors: Williams Gwyn , Fisher Sheila , Sule-Suso Josep , Chalmers John M , Cinque Gianfelice , Byrne Hugh J , Sockalingum Ganesh , Stone Nick , Lyng Fiona M , Gazi Ehsan , Gardner Peter , Lasch Peter , Petrich Wolfgang , Carr Larry , Miller Lisa , Dumas Paul , Tobin Mark , Kretlow Ariane , Kneipp Janina , Naumann Dieter , Wood Bayden , McNaughton Don , Holman Hoi-Ying N , Blankenberg Francis , Mantsch Henry ,   Forschungszentrum Karlsruhe GmbH
Published: December 2010

Publication of a multi-author textbook on the biomedical applications of synchrotron infrared microspectroscopy was a central element in the workplan of the EU project DASIM (Diagnostic Applications of Synchrotron Infrared Microspectroscopy). The project involved nearly 70 scientists and clinicians from 9 European countries, including all synchrotron facilities that have or are planning an infrared beamline. Together with its international associates from the USA, Canada and Australia, the project brought together essentially all recognized experts in the field. The project aims were to coordinate international research effort and to disseminate the relevant information amongst biological researchers and health care professionals and this multi-author textbook was conceived as the most important measure towards the aim of dissemination. The field of biomedical applications of synchrotron IR microspectroscopy, which has recently seen unprecedented growth, is extremely interdisciplinary, involving synchrotron physicists, spectroscopists, biologists and clinicians, with associated difficulties in getting these experts to understand each other. This multi-author book, from leading world experts, presents all aspects of the field in language that all the disparate experts involved can understand. It demystifies the subject both for clinicians and biologists who find synchrotron physics difficult to understand and for physicists who find medical/biological terminology incomprehensible. The book focuses specifically on biomedical IR spectroscopy using synchrotron light sources with particular emphasis on understandable presentation of necessary background knowledge, digestible summaries of research progress and above all as a practical 'how to do it' guide for those working in or wishing to enter the field of biomedical synchrotron IR microspectroscopy and imaging. Key features of the book include:- * a 'Fundamentals' section, explaining the basics of synchrotrons and FTIR spectroscopy as well as the needs of clinicians and biologists with respect to these technologies * a 'Technical Aspects' section, going into depth on optical issues, sample preparation and study design/data analysis * case studies bringing together these 2 elements through practical examples * Raman microspectroscopy, as an alternative approach, is explored in depth * the foreword is written by Henry Mantsch and Gwynn Williams, the two undisputed experts in the fields of biomedical FTIR spectroscopy and synchrotron IR microspectroscopy respectively
Hydrogen bond perturbation in hen egg white lysozyme by external electromagnetic fields: A nonequilibrium molecular dynamics study
Authors: Solomentsev Gleb Y. , English Niall J. , Mooney Damian A.
Published: December 2010

Nonequilibrium molecular dynamics simulations of a charge-neutral mutant of hen egg white lysozyme have been performed at 300 K and 1 bar in the presence of external microwave fields (2.45 to 100 GHz) of an rms electric field intensity of 0.05 V Å−1. A systematic study was carried out of the distributions of persistence times and energies of each intraprotein hydrogen bond in between breakage and reformation, in addition to overall persistence over 20 ns simulations, vis-à-vis equilibrium, zero-field conditions. It was found that localized translational motion for formally charged residues led to greater disruption of associated hydrogen bonds, although induced rotational motion of strongly dipolar residues also led to a degree of hydrogen bond perturbation. These effects were most apparent in the solvent exposed exterior of hen egg white lysozyme, in which the intraprotein hydrogen bonds tend to be weaker.