bluuebunny/crossref_metadata_2025 huggingface dataset:
Biphasic Pattern of Depression and Its Predictors during Pegylated Interferon-Based Therapy in Chronic Hepatitis B and C Patients
Authors: Huang Yi-Wen , Hu Jui-Ting , Hu Fu-Chang , Chang Ching-Jui , Chang Han-Yu , Kao Jia-Horng , Yang Sien-Sing , Chen Ding-Shinn
Published: October 2012

Background

It remains unclear whether depression in chronic hepatitis B (CHB) and chronic hepatitis C (CHC) during pegylated interferon-based therapy is associated with the virus, drug or ethnic background. We aimed to perform a prospective study to evaluate the clinical course of depression and its predictors in consecutive non-cirrhotic CHB and CHC patients of the same ethnicity receiving pegylated interferon-based therapy.

Methods

The occurrence and severity of depression were actively assessed by the Hamilton Depression Rating Scale before therapy and at weeks 2, 4, 6, 8, 10, 12 and every 4 weeks during treatment until the end of therapy. Extensive numbers of variables (repeated measurements, time variables and interactions between all variables) were included in generalized estimating equations to analyse the predictors of depression.

Results

A total of 158 consecutive patients (73 CHB and 85 CHC patients) were enrolled. Depression (Hamilton Depression Rating Scale ≥11) occurred in a biphasic pattern at treatment weeks 2-10 and weeks 16-36. Treatment weeks <10 predicts more depression, and treatment weeks >12 predicts less depression, suggesting the predictability of the time variable during treatment on depression. Furthermore, CHC or pre-existing depression is an independent predictor of depression in these patients ( P<0.001).

Conclusions

Depression occurred in a biphasic pattern during pegylated interferon-based therapy and should be early and actively assessed, especially in patients with CHC or pre-existing depression.
Mucosal Kaposi sarcoma, a Rare Cancer Network study
Authors: Thariat Juliette , Kirova Youlia , Sio Terence , Choussy Olivier , Vees Hans , Schick Ulrich , Poissonnet Gilles , Saada Esma , Thyss Antoine , Miller Robert C.
Published: October 2012

Kaposi's sarcoma (KS) most often affect the skin but occasionally affect the mucosa of different anatomic sites. The management of mucosal KS is seldom described in the literature. Data from 15 eligible patients with mucosal KS treated between 1994 and 2008 in five institutions within three countries of the Rare Cancer Network group were collected. The inclusion criteria were as follows: age >16 years, confirmed pathological diagnosis, mucosal stages I and II, and a minimum of 6 months’ follow-up after treatment. Head and neck sites were the most common (66%). Eleven cases were HIV-positive. CD4 counts correlated with disease stage. Twelve patients had biopsy only while three patients underwent local resection. Radiotherapy (RT) was delivered whatever their CD4 status was. Median total radiation dose was 16.2 Gy (0–45) delivered in median 17 days (0–40) with four patients receiving no RT. Six patients underwent chemotherapy and received from 1 to 11 cycles of various regimens namely vinblastin, caelyx, bleomycine, or interferon, whatever their CD4 counts was. Five-year disease free survival were 81.6% and 75.0% in patients undergoing RT or not, respectively. Median survival was 66.9 months. Radiation-induced toxicity was at worse grade 1–2 and was manageable whatever patients’ HIV status. This small series of mucosal KSs revealed that relatively low-dose RT is overall safe and efficient in HIV-positive and negative patients. Since there are distant relapses either in multicentric cutaneous or visceral forms in head and neck cases, the role of systemic treatments may be worth investigations in addition to RT of localized disease. Surgery may be used for symptomatic lesions, with caution given the risk of bleeding.
Clinical profile of parkinsonian disorders in the tropics: Experience at Kano, northwestern Nigeria
Authors: Femi Owolabi Lukman , Ibrahim A , Aliyu S
Published: October 2012

Background: No data exists on Parkinson’s disease (PD) and secondary Parkinsonism in Northwestern Nigeria. This study was designed to create a database, document the clinical profile of PD in Kano, northwestern Nigerian, and compare this to prior observations within and outside Nigeria. Materials and Methods: A database was documented on prospective patients presenting consecutively to the Neurology out-patients clinic of the two tertiary health facilities in Kano northwestern Nigeria over a period of 4 years. Demographic and clinical data at presentation were documented for all patients. Cases were classified as PD or secondary Parkinsonism. The severity at presentation and at last visit was classified using the H and Y scale. Results: Over a period of 4 years, out 1153 a total of 96 patients comprising 74 males and 22 females were enrolled. Eighty (83.3%) of them had clinically diagnosed PD while 16 (16.7%) had clinical features compatible with secondary Parkinsonism. The mean age at onset of symptoms in the PD patients (mean 58.2 ± 6.72 yrs ) was more than in secondary Parkinsonism (mean 51.4 ± 10.04 and P = 0.001). There was male preponderance in both idiopathic Parkinsonism (PD) (m:f = 3.2:1) and secondary Parkinsonism (m:f = 4.3:1). Out of the patients with secondary Parkinsonism, 10 (62.5%) and 5 (31.3%) had vascular Parkinsonism and drug-induced Parkinsonism, respectively. Duration of symptoms prior to presentation ranged between 3 months and 16 years. The mean (SD) time interval from the onset of motor symptoms to diagnosis of PD was 3.6 ± 3.4 yrs and time interval for men and women (male 3.8 ± 3.7; female 2.8 ± 2.1; P = 0.249). Conclusions: Clinical profile of patients with PD and secondary Parkinsonism in Kano is similar to that from other populations within Nigeria and other developing countries. However, delayed presentation, less frequent family history, lower frequency of Young-onset PD as well as treatment challenges occasioned by poverty, inadequacy of expert, and lack of newer drugs and treatment options contrasts the situation in western populations.
Tuberculum sellae meningiomas: A series of 41 cases; surgical and ophthalmological outcomes with proposal of a new prognostic scoring system
Authors: Palani Arun , Panigrahi Manas K , Purohit Anirudh K
Published: October 2012

Context: Tuberculum sellae meningiomas have proved difficult to treat, partly because of their intimate association with the optic nerves and chiasma, hypothalamus, and internal carotid arteries. Aims: The aim of this study is to analyze the degree of influence of various prognostic factors affecting visual outcome; the pattern of visual recovery and develop a scoring system for prognostication. Settings and Design: This is a retrospective study carried out from January 2004 till June 2011. Materials and Methods: Patients were analyzed on the basis of clinical, radiological, and surgical factors that appeared to affect the outcome. A special scoring system (according to the guidelines of the German Ophthalmological Society) was adopted to quantify the extent of ophthalmological disturbances. Statistical Analysis Used: Comparison of categorical variables between the two was performed using chi-square test and a P value of ≤ 0.05 was considered significant. Logistic regression was used when multivariate analysis was required. Results: Vision improved in 27% and deteriorated in 7.3%. A prognostic scoring system (score 4–13) was developed depending on the degree of influence of significant prognostic factors. The patients with a score of ≤6 had improved vision postoperatively (44%), whereas none of those with a score > 6 improved. Completeness of visual recovery was perceived in 100% of patients within 3 months. Complete resectability was achieved in 73% of patients. Conclusions: The proposed scoring system is very useful in prognosticating the visual outcome of these patients. The patients with a score of ≤6 have the best visual outcome postoperatively. Complete resectability is better achieved with extended bifrontal and unilateral frontal approaches. Short-term postoperative visual outcome is a strong indicator of permanent visual outcome after surgery.
Spinal epidural angiolipoma: A rare cause of spinal cord compression
Authors: Ghanta Rajesh K , Koti Kalyan , Dandamudi Srinivas
Published: October 2012

Spinal epidural angiolipomas are rare, benign tumors composed of mature lipocytes admixed with abnormal blood vessels. Only 128 cases of spinal epidural angiolipomas have been reported in literature till now. Spinal angiolipomas are predominantly located in the mid-thoracic region. We report a case of dorsal epidural angiolipoma in a 56-year-old male who presented with paraparesis and was diagnosed to have D4-5 epidural angiolipoma. Total surgical excision of the epidural angiolipoma was done and his paraparesis gradually improved.
Epidermoid cyst causing hemifacial spasm epidermoid cyst in cerebellopontine angle presenting with hemifacial spasm
Authors: Alemdar Murat
Published: October 2012

Hemifacial Spasm (HS) occurs idiopathically or secondary to the lesions compressing the root exit zone of the facial nerve symptomatically. Symptomatic HS is generally due to vascular compression. We report on a 23-year-old male with right sided HS for a month. Magnetic resonance imaging (MRI) of the brain revealed a well-demarcated epidermoid cyst in the right cerebellopontine cistern. It was hypointense on T1-weighted imaging, hyperintense on T2-weighted imaging without contrast enhancement, hyperintense on DWI, and slightly hypointense on ADC relative to the brain. Although it caused shifting of the pons and medulla to the left side and compression of the right cerebellar peduncles and fourth ventricle, the sole symptom of the patient was HS. Clinicians are advised to request MRI/scan for brainstem lesions from the patients with HS. Epidermoid cysts in cerebellopontine cistern may present with HS as the sole symptom.
Cervical Subependymoma: A rare case report with possible histogenesis
Authors: Krishnan Shyam Sundar , Panigrahi Manas , Pendyala Swetha , Rao Satish I. , Varma Dandu R.
Published: October 2012

Subependymomas are extremely rare lesions of the spinal cord. Only 33 cases including ours have been reported in the cervical cord. These are typically benign slow growing tumors occurring eccentrically within the cord, producing minimal neurological deficits. The clinical, radiological, and histopathological aspects of this unusual lesion have been reviewed in detail. As the histogenesis of this tumor is much debated, we propose an alternate origin for the same.
Myxoid chondrosarcoma of sphenoid bone
Authors: Chowhan Amit K. , Rukmangadha Nandyala , Patnayak Rashmi , Reddy Mandyam Kumaraswamy , Prasad Bodapati Chandra Mouliswara , Bodagala Vijaya Laxmi
Published: October 2012

The myxoid variant of chondrosarcoma is usually seen in soft tissues where it is known as chordoid sarcoma or parachordoma. Rarely, it involves bone and when it does, cranial bones are the preferred location. This tumor is frequently amalgamated with the chondroid variant of chordoma, especially when the lesion occurs in the sphenoid bone/spheno-occipital region, because of their similar clinical presentations, anatomical locations, radiological findings, and mistaken histopathological features. It is essential to distinguish myxoid chondrosarcoma from the chondroid variant of chordoma, because of the different treatment protocol and prognostic importance. We present such a location-based diagnostic dilemma, solved successfully with ancillary immunohistochemistry.
A visit to the stroke belt of the United States
Authors: Bathala Lokesh
Published: October 2012

Southeastern part of United States has been called the Stroke Belt due to a much higher incidence of stroke compared to the rest of the country. In this article, I summarize my 2 weeks of observations as a clinical preceptor at the Comprehensive Stroke Center, University of Alabama Hospital, Birmingham, AL. 57 patients were admitted during these 2 weeks, 61% had ischemic strokes, and 23% received intravenous recombinant tissue plasminogen activator (IV rt-PA). Endovascular neuro-interventionalists were performing diagnostic catheter angiography in 14% and emergent revascularization procedures in 7% of consecutive patients. Also, the stroke team enrolled 6 patients into National institute of health (NIH) funded clinical trials (3 Argatroban tPA stroke study (ARTSS), 2 Safety study of external counter pulsation as a treatment for acute ischemic stroke (CUFFS), 1 stenting and aggressive medical management for preventing recurrent stroke in intracranial stenosis (SAMMPRIS). In my opinion, these observations provided me with useful knowledge how to develop a cutting edge, proactive stroke treatment system. In particular, availability 24 × 7 and consistent application of a curative, “finding reasons to treat approach” coupled with state-of the-art technologies and skilled operators could make a huge difference.
Duplicate Orders: An Unintended Consequence of Computerized provider/physician order entry (CPOE) Implementation
Authors: Forrer C. , Shaha S. , Magid S.
Published: October 2012

Objective: Computerized provider/physician order entry (CPOE) with clinical decision support (CDS) is designed to improve patient safety. However, a number of unintended consequences which include duplicate ordering have been reported. The objective of this time-series study was to characterize duplicate orders and devise strategies to minimize them.

Methods: Time series design with systematic weekly sampling for 84 weeks. Each week we queried the CPOE database, downloaded all active orders onto a spreadsheet, and highlighted duplicate orders. We noted the following details for each duplicate order: time, order details (e.g. drug, dose, route and frequency), ordering prescriber, including position and role, and whether the orders originated from a single order or from an order set (and the name of the order set). This analysis led to a number of interventions, including changes in: order sets, workflow, prescriber training, pharmacy procedures, and duplicate alerts.

Results: Duplicates were more likely to originate from different prescribers than from same prescribers; and from order sets than from single orders. After interventions, there was an 84.8% decrease in the duplication rate from weeks 1 to 84 and a 94.6% decrease from the highest (1) to the lowest week (75). Currently, we have negligible duplicate orders.

Conclusions: Duplicate orders can be a significant unintended consequence of CPOE. By analyzing these orders, we were able to devise and implement generalizable strategies that significantly reduced them. The incidence of duplicate orders before CPOE implementation is unknown, and our data originate from a weekly snapshot of active orders, which serves as a sample of total active orders. Thus, it should be noted that this methodology likely under-reports duplicate orders.

Citation: Magid S, Forrer C, Shaha S. Duplicate Orders: An unintended consequence of computerized provider/physician order entry (CPOE) implementation. Analysis and mitigation strategies. Appl Clin Inf 2012; 3: 377–391

http://dx.doi.org/10.4338/ACI-2012-01-RA-0002
Assessment of Intergranular Corrosion Attack in Austenitic Stainless Steel Using Ultrasonic Measurements
Authors: Jothilakshmi N. , Nanekar P.P. , Kain V.
Published: October 2012

The structural materials of reprocessing and waste management plants are made from AISI Type 304L (UNS S30403) grade austenitic stainless steels and are prone to localized corrosion attack like intergranular corrosion (IGC). It is very important to detect and characterize this attack non-destructively. An ultrasonic-based, non-destructive evaluation technique has been developed to detect and estimate the depth of IGC attack in Type 304 (UNS S30400) stainless steel grade plate. Samples with varying degrees of IGC attack were generated in laboratory and used for this study. Ultrasonic measurement involved determination of sound velocity in longitudinal mode, longitudinal to shear velocity ratio, sound attenuation measurement, and spectral analysis. The elastic modulus measurement using a nano-hardness tester was carried out to formulate the basis of change in sound velocity in the IGC-attacked samples as compared to the virgin sample. This paper gives the details on the sample preparation method used for generation of IGC attack in Type 304 stainless steel plate and reports the results of ultrasonic measurement on the characterization of IGC attack. The results are compared with maximum depth of IGC attack estimated by microscopic examination.
Localized Corrosion: An Empirical Approach to the Study of Passive Film Breakdown Rates
Authors: Bolzoni F. , Contreras G. , Fumagalli G. , Lazzari L. , Re G.
Published: October 2012

Electrochemical tests lasting 600 h to 6,000 h, at different potentials, were carried out on Type 316L (UNS S31603), Type 904L (UNS N08904), and nickel alloy 825 (UNS N08895) in sodium chloride (NaCl) solutions. A statistical approach was adopted using samples of 10 to 60 specimens. The pitting or crevice corrosion behavior was reported using cumulative frequency of passive film breakdown vs. time. In this work, we considered the formation of stable occluded cells as the breakdown of passive film. Each corrosion system “passive alloy-environment-geometry-time” was characterized by straight lines (i.e., breakdown rate of passive film, ρb), with a higher slope in the initial stage and a lower slope after some tens/hundreds of hours. The ρb can be used in the design for material selection and industrial maintenance schedules.
Effect of TiO2 on the Repassivation Kinetics of Alloy 600 in Caustic Solutions
Authors: Toor I. , Ejaz M. , Kwon H.-S.
Published: October 2012

Effects of titanium dioxide (TiO2) inhibitor on repassivation kinetics and defect density of the passive film formed on Alloy 600 (UNS N06600) were examined. Addition of 0.05 g/L TiO2 powder increased the repassivation rate of Alloy 600. Passive film initially nucleated and grew according to the place exchange model in which log i(t) is linearly proportional to q(t), and later it grew according to high-field ion conduction model in which log i(t) is linearly proportional to the 1/q(t). Ti enrichment in the film decreased the defect density of the film and increased its protectiveness.
Source attribution and radiative impacts of the Mediterranean summertime ozone maximum: a satellite and model perspective
Authors: Richards N. A. D. , Arnold S. R. , Chipperfield M. P. , Miles G. , Rap A. , Siddans R. , Monks S. A. , Hollaway M. J.
Published: October 2012

Abstract. The Mediterranean troposphere exhibits a marked and localised summertime ozone maximum, which has the potential to strongly impact regional air quality and radiative forcing. The Mediterranean region can be perturbed by long-range pollution import from Northern Europe, North America and Asia, in addition to local emissions, which may all contribute to regional ozone enhancements. We exploit ozone profile observations from the Tropospheric Emission Spectrometer (TES) and the Global Ozone Monitoring Experiment-2 (GOME-2) satellite instruments, and an offline 3-D global chemical transport model (TOMCAT) to investigate the geographical and vertical structure of the summertime tropospheric ozone maximum over the Mediterranean region. We show that both TES and GOME-2 are able to detect enhanced levels of ozone in the lower troposphere over the region during the summer. These observations, together with surface measurements, are used to evaluate the TOMCAT model's ability to capture the observed ozone enhancement. The model is used to quantify contributions to the ozone maximum from anthropogenic and natural volatile organic compound (VOC) emissions, anthropogenic NOx emissions, wildfire emissions and long-range import of ozone and precursors. Our results show a dominance of natural VOC emissions on ozone in the Mediterranean Basin over anthropogenic VOC emissions. However, local anthropogenic NOx emissions are the overall dominant contribution to near-surface ozone. We also show that in the lower troposphere, global VOC emissions account for 40% of the VOC contribution to ozone in the region, whereas, for NOx the global contribution is only 10% at these altitudes. However, in the mid and upper troposphere almost all of the ozone comes from long-range transport for all emission sources. In terms of radiative effects on regional climate, ozone contributions from non-local sources are more important with Asian monsoon outflow having the greatest impact. Our results allow improved understanding of the large-scale processes controlling air quality and climate in the region of the Mediterranean Basin.
Receptor modelling of secondary particulate matter at UK sites
Authors: Charron A. , Degrendele C. , Laongsri B. , Harrison R. M.
Published: October 2012

Abstract. Complementary approaches have been taken to better understand the sources and their spatial distribution for secondary inorganic (nitrate and sulphate) and secondary organic aerosol sampled at a rural site (Harwell) in the southern United Kingdom. A concentration field map method was applied to 1581 daily samples of chloride, nitrate and sulphate from 2006 to 2010, and 982 samples for organic carbon and elemental carbon from 2007 to 2010. This revealed a rather similar pattern of sources for nitrate, sulphate and secondary organic carbon within western/central Europe, which in the case of nitrate and sulphate, correlated significantly with EMEP emissions maps of NOx and SO2. A slightly more southerly source emphasis for secondary organic carbon may reflect the contribution of biogenic sources. Trajectory clusters confirm this pattern of behaviour with a major contribution from mainland European sources. Similar behaviours of, on the one hand, sulphate and organic carbon and, on the other hand, EC and nitrate showed that the former are more subject to regional influence than the latter in agreement with the slower atmospheric formation of sulphate and secondary organic aerosol than for nitrate, and the local/mesoscale influences upon primary EC. In a separate study, measurements of sulphate, nitrate, elemental and organic carbon were made in 100 simultaneously collected samples at Harwell and at a suburban site in Birmingham (UK). This showed a significant correlation in concentrations between the two sites for all of the secondary constituents, further indicating secondary organic aerosol to be a regional pollutant behaving similarly to sulphate and nitrate.
Intercomparison Study of the CAPS PMex (Cavity Attenuated Phase Shift Particle Light Extinction Monitor) with the combination of an Integrating Nephelometer and a Particle Soot Absorption Photometer
Authors: Petzold A. , Onasch T. , Kebabian P. , Freedman A.
Published: October 2012

Abstract. An evaluation of the Cavity Attenuated Phase Shift particle light extinction monitor (CAPS PMex) by means of a combination of a 3-wavelength Integrating Nephelometer (NEPH; TSI Model 3563) and a 3-wavelength filter-based Particle Soot Absorption Photometer (PSAP) was carried out using both laboratory generated test particles and ambient aerosols. An accurate determination of a fixed pathlength correction for the CAPS PMex was made by comparing extinction measurements using polystyrene latex (PSL) spheres in combination with Mie scattering calculations to account for the presence of PSL conglomerates. These studies yielded a linear instrument response over the investigated dynamical range from 20 to 450 M m−1 (10−6 m−1) with a linear correlation coefficient of R2 > 0.98. The adjustment factor was determined to be 1.05 times that previously reported. Correlating CAPS extinction to extinction measured by the NEPH-PSAP combination using laboratory-generated polydisperse mixtures of purely scattering ammonium sulfate and highly absorbing black carbon provided a linear regression line with slope m = 0.99 (R2 = 0.996) for single-scattering albedo values (λ = 630 nm) ranging from 0.35 (black carbon) to 1.00 (ammonium sulfate). For ambient aerosol, light extinction measured by CAPS PMex was highly correlated (R2 = 0.995) to extinction measured by the NEPH-PSAP combination with slope m = 0.95.
The response of methane and nitrous oxide fluxes to forest change in Europe
Authors: Gundersen P. , Christiansen J. R. , Alberti G. , Brüggemann N. , Castaldi S. , Gasche R. , Kitzler B. , Klemedtsson L. , Lobo-do-Vale R. , Moldan F. , Rütting T. , Schleppi P. , Weslien P. , Zechmeister-Boltenstern S.
Published: October 2012

Abstract. Forests in Europe are changing due to interactions between climate change, nitrogen (N) deposition and new forest management practices. The concurrent impact on the forest greenhouse gas (GHG) balance is at present difficult to predict due to a lack of knowledge on controlling factors of GHG fluxes and response to changes in these factors. To improve the mechanistic understanding of the ongoing changes, we studied the response of soil–atmosphere exchange of nitrous oxide (N2O) and methane (CH4) at twelve experimental or natural gradient forest sites, representing anticipated future forest change. The experimental manipulations, one or more per site, included N addition (4 sites), changes of climate (temperature, 1 site; precipitation, 2 sites), soil hydrology (3 sites), harvest intensity (1 site), wood ash fertilisation (1 site), pH gradient in organic soil (1 site) and afforestation of cropland (1 site). On average, N2O emissions increased by 0.06 ± 0.03 (range 0–0.3) g N2O-N m−2 yr−1 across all treatments on mineral soils, but the increase was up to 10 times higher in an acidic organic soil. Soil moisture together with mineral soil C / N ratio and pH were found to significantly influence N2O emissions across all treatments. Emissions were increased by elevated N deposition, especially in interaction with increased soil moisture. High pH reduced the formation of N2O, even under otherwise favourable soil conditions. Oxidation (uptake) of CH4 was on average reduced from 0.16 ± 0.02 to 0.04 ± 0.05 g CH4-C m−2 yr−1 by the investigated treatments. The CH4 exchange was significantly influenced by soil moisture and soil C / N ratio across all treatments, and CH4 emissions occurred only in wet or water-saturated conditions. For most of the investigated forest manipulations or natural gradients, the response of both N2O and CH4 fluxes was towards reducing the overall GHG forest sink. The most resilient forests were dry Mediterranean forests, as well as forests with high soil C / N ratio or high soil pH. Mitigation strategies may focus on (i) sustainable management of wet forest areas and forested peatlands, (ii) continuous forest cover management, (iii) reducing atmospheric N input and, thus, N availability, and (iv) improving neutralisation capacity of acid soils (e.g. wood ash application).
Diapycnal oxygen supply to the tropical North Atlantic oxygen minimum zone
Authors: Fischer T. , Banyte D. , Brandt P. , Dengler M. , Krahmann G. , Tanhua T. , Visbeck M.
Published: October 2012

Abstract. The replenishment of consumed oxygen in the open ocean oxygen minimum zone (OMZ) off West Africa in the tropical North Atlantic Ocean is studied, with a focus on oxygen transport across density surfaces (diapycnal flux). The latter is obtained from a large observational set of oxygen profiles and diapycnal mixing data from years 2008 to 2010. Diapycnal mixing is inferred from different sources: a large scale tracer release experiment, microstructure profiles, and shipboard acoustic current measurements plus density profiles. The average diapycnal diffusivity in the study area is 1 × 10−5 m2 s−1. No significant vertical gradient of average diapycnal diffusivities exists in the depth interval from 150 to 500 m. The diapycnal flux is found to contribute substantially to the oxygen supply of the OMZ. Within the OMZ core, 1.5 µmol kg−1 a−1 of oxygen is supplied via diapycnal mixing, contributing about a third of the total demand. The oxygen that is contributed via diapycnal mixing originates from oxygen that has been laterally supplied within the overlying Central Water layer by advective and eddy fluxes. Due to the existence of a separate shallow oxygen minimum at about 100 m depth throughout most of the study area, there is no direct net vertical oxygen flux from the surface layer of the study area into the Central Water layer. Thus all oxygen supply of the OMZ is associated with remote pathways.
Climate-related changes in peatland carbon accumulation during the last millennium
Authors: Charman D. J. , Beilman D. W. , Blaauw M. , Booth R. K. , Brewer S. , Chambers F. M. , Christen J. A. , Gallego-Sala A. , Harrison S. P. , Hughes P. D. M. , Jackson S. T. , Korhola A. , Mauquoy D. , Mitchell F. J. G. , Prentice I. C. , van der Linden M. , De Vleeschouwer F. , Yu Z. C. , Alm J. , Bauer I. E. , Corish Y. M. C. , Garneau M. , Hohl V. , Huang Y. , Karofeld E. , Le Roux G. , Loisel J. , Moschen R. , Nichols J. E. , Nieminen T. M. , MacDonald G. M. , Phadtare N. R. , Rausch N. , Sillasoo Ü. , Swindles G. T. , Tuittila E.-S. , Ukonmaanaho L. , Väliranta M. , van Bellen S. , van Geel B. , Vitt D. H. , Zhao Y.
Published: October 2012

Abstract. Peatlands are a major terrestrial carbon store and a persistent natural carbon sink during the Holocene, but there is considerable uncertainty over the fate of peatland carbon in a changing climate. It is generally assumed that higher temperatures will increase peat decay, causing a positive feedback to climate warming and contributing to the global positive carbon cycle feedback. Here we use a new extensive database of peat profiles across northern high latitudes to examine spatial and temporal patterns of carbon accumulation over the past millennium. Opposite to expectations, our results indicate a small negative carbon cycle feedback from past changes in the long-term accumulation rates of northern peatlands. Total carbon accumulated over the last 1000 yr is linearly related to contemporary growing season length and photosynthetically active radiation, suggesting that variability in net primary productivity is more important than decomposition in determining long-term carbon accumulation. Furthermore, northern peatland carbon sequestration rate declines over the climate transition from the Medieval Climate Anomaly (MCA) to the Little Ice Age (LIA), probably because of lower LIA temperatures combined with increased cloudiness suppressing net primary productivity. Other factors including changing moisture status, peatland distribution, fire, nitrogen deposition, permafrost thaw and methane emissions will also influence future peatland carbon cycle feedbacks, but our data suggest that the carbon sequestration rate could increase over many areas of northern peatlands.
Organic carbon transport and impacts of human activities in the Yellow River
Authors: Zhang L. J. , Wang L. , Cai W.-J. , Liu D. M. , Yu Z. G.
Published: October 2012

Abstract. Based on four field investigations during 2003 and 2009 along the Yellow River mainstream, we examined the distributions, seasonal variations and transport features of organic carbon, with a focus on the impacts of human activities (reservoir construction and regulation scheme). The results showed that organic carbon transport processes in the Yellow River were different from other major rivers. Particulate organic carbon (POC) dominated in the Yellow River and it mainly originated from the Loess Plateau. POC levels in suspended sediment (POC %) ranged between 0.25% and 2.20% and more than 80% of POC concentrated in the particles with grain size smaller than 16 μm. On time scale, dissolved organic carbon (DOC) correlated negatively with discharges, indicating the influence of dilution effect. Along the river on spatial scales, DOC in the Qinghai-Tibet Plateau was closely related with temperature while DOC in the Loess Plateau showed the concentration effect, due to the abundant human input and the high ratio of evaporation to precipitation. Organic carbon in the Yellow River was very refractory and about 90% of POC and 70% of DOC cannot be degraded. Due to the high turbidity, the Yellow River suffers more impacts from the reservoirs in the transport of total suspended solids (TSS) and organic carbon. Ratios of DOC/POC ranged between 2.0 and 12 in the reservoirs and organic carbon was mainly in the dissolved from. POC deposited in the reservoirs of the Yellow River achieved 0.0033 Gt a−1, about 8 times its annual POC flux discharged to the ocean. During the 2008 Water and Sediment Regulation (WSR) period, DOC and POC fluxes was as high as 1.1 × 1010 g and 2.2 × 1011 g respectively, accounting for 35% of annual DOC flux and 56% of the annual POC flux to the ocean. Discharges and material fluxes to the ocean decline sharply due to the reservoir construction while large amounts of water and sediment are transported to the ocean in such a~short WSR period. These two human disturbances totally altered the processes of substance transport in the Yellow River, and may change the water chemical characteristics in the coastal zones.
Methane emission measurements in a cattle grazed pasture: a comparison of four methods
Authors: Tallec T. , Klumpp K. , Hensen A. , Rochette Y. , Soussana J.-F.
Published: October 2012

Abstract. Methane (CH4) is considered to be the second main contributor to the global greenhouse gas effect, with major CH4 emissions originating from livestock. Accurate measurements from ruminating herds are required to improve emission coefficients used in national emission inventories, and to evaluate mitigation strategies. Previous measurements of enteric methane emissions from domestic animals have been carried out in artificial conditions such as laboratory chambers, or by fitting individual animals with capillary tubes and using SF6 as a tracer. Here we evaluated the reliability of eddy covariance technique (EC), already used for CO2 fluxes, for continuous CH4 measurements over a grazed field plot. Analyzer accuracy and reliability of eddy covariance technique were tested against field scale measurements with the SF6 tracer technique, Gaussian plume model and emission factors (i.e. IPCC). Results indicate a better agreement between EC and SF6 method when grazing heifers were parked close to the EC setup. However, a systematic underestimation of EC data appeared and even more when the distance between the source (ruminating heifers) and EC setup (mast) was increased. A two-dimensional footprint density function allowed to correct for the dilution effect on measured CH4 and led to a good agreement with results based on the SF6 technique (on average 231 and 252 g CH4 ha−1 over the grazing experiment, respectively). Estimations of the CH4 budgets for the whole grazing season were in line with estimates (i.e. emission factor coefficients) based on feed intake and animal live weight as well as SF6 technique. IPCC method Tier 2, however, led to an overestimation of CH4 fluxes on our site.
Description of a hybrid ice sheet-shelf model, and application to Antarctica
Authors: Pollard D. , DeConto R. M.
Published: October 2012

Abstract. The formulation of a 3-D ice sheet-shelf model is described. The model is designed for long-term continental-scale applications, and has been used mostly in paleoclimatic studies. It uses a hybrid combination of the scaled shallow ice and shallow shelf approximations for ice flow. Floating ice shelves and grounding-line migration are included, with parameterized ice fluxes at grounding lines that allows relatively coarse resolutions to be used. All significant components and parameterizations of the model are described in some detail. Basic results for modern Antarctica are compared with observations, and simulations over the last 5 million years are compared with previously published results. The sensitivity of ice volumes during the last deglaciation to basal sliding coefficients is discussed.
Implementation of the Fast-JX Photolysis scheme into the UKCA component of the MetUM chemistry climate model
Authors: Telford P. J. , Abraham N. L. , Archibald A. T. , Braesicke P. , Dalvi M. , Morgenstern O. , O'Connor F. M. , Richards N. A. D. , Pyle J. A.
Published: October 2012

Abstract. Atmospheric chemistry is driven by photolytic reactions, making their modelling a crucial component of atmospheric models. We describe the implementation and validation of Fast-JX, a state of the art model of interactive photolysis, into the MetUM chemistry climate model. This allows for interactive photolysis frequencies to be calculated in the troposphere and augments the calculation of the frequencies in the stratosphere by accounting for clouds and aerosols in addition to ozone. In order to demonstrate the effectiveness of this new photolysis scheme we employ new methods of validating the model, including techniques for sampling the model to compare to flight track and satellite data.
Transient analysis of fluctuations of electrical conductivity as tracer in the stream bed
Authors: Schmidt C. , Musolff A. , Trauth N. , Vieweg M. , Fleckenstein J. H.
Published: October 2012

Abstract. Spatial patterns of water flux in the stream bed are controlled by the distribution of hydraulic conductivity, bedform-induced head gradients and the connectivity to the adjoining groundwater system. The water fluxes vary over time driven by short-term flood events or seasonal variations in stream flow and groundwater level. Variations of electrical conductivity (EC) are used as a natural tracer to detect transient travel times and flow velocities in an in-stream gravel bar. We present a method to estimate travel times between the stream and measuring locations in the gravel bar by non-linearly matching the EC signals in the time domain. The amount of temporal distortion required to obtain the optimal matching is related to the travel time of the signal. Our analysis revealed that the travel times increase at higher stream flows because lateral head gradients across the gravel bar become significantly smaller at the time.
X-band COSMO-SkyMed© SAR data for sea wave simulations and coastal vulnerability assessment
Authors: Benassai G. , Montuori A. , Migliaccio M. , Nunziata F.
Published: October 2012

Abstract. In this paper, X-band COSMO-SkyMed© Synthetic Aperture Radar (SAR) data are first experimented as wind field forcing of coastal wind-wave oceanographic modeling for both sea-wave numerical simulation and coastal vulnerability assessment purposes. The SAR data set consists of 60 X-band VV-polarized Level 1B Detected Ground Multi-look (DGM) ScanSAR Huge Region COSMO-SkyMed© SAR measurements, collected in the test area of the Southern Tyrrhenian Coastal basin during the winter season of 2010. On one hand, the wind-wave oceanographic modeling is based on the third-generation Simulating WAves Nearshore (SWAN) model, which is used for sea wave state estimation in coastal and island regions. On the other hand, the coastal vulnerability assessment model is based on the use of a key parameter known as impact index, which consistently provides the coastal risk evaluation due to the inundation of the inshore land. Experiments consist of numerical wave simulations of the SWAN model accomplished with respect to some relevant wave storms recorded in the test area during the winter season of 2010. The wind forcing is provided by X-band COSMO-SkyMed© SAR-based wind field estimations which are properly blended with both buoys wave data and ECMWF model winds to retrieve meaningful wave parameters (e.g. significant wave height, wave directions and periods) as physical descriptors of tidal events. The output of numerical wave simulations are used to perform the coastal vulnerability assessment in the considered test area along the coastal plain of river Sele. The assessment is accomplished in terms of wave run-up height, storm beach retreat and both short- and long-term erosion shoreline evolution. Experimental results accomplished with X-band COSMO-SkyMed© SAR-based wind field forcing are successfully compared with the ones gathered by using both buoys wave field data and ECMWF model winds, only. They demonstrate that both wind-wave interaction modeling and coastal vulnerability assessment can take full benefits of blended wind field products composed by X-band COSMO-SkyMed© SAR wind field estimations and model data.
Nature of orogenesis and volcanism in the Caucasus region based on results of regional tomography
Authors: Koulakov I. , Zabelina I. , Amanatashvili I. , Meskhia V.
Published: October 2012

Abstract. In the paper, we discuss the problem of continental collision and related volcanism in the Caucasus and surrounding areas based on the analysis of the upper mantle seismic structure in a recently derived model by Koulakov (2011). This model, which includes P and S-velocity anomalies down to 1000 km depth, was obtained from tomographic inversion of worldwide travel time data from the catalogue of the International Seismological Center. It can be seen that the Caucasus region is squeezed between two continental plates, Arabian to the south and European to the north, which are displayed in the tomographic model as high-velocity bodies down to about 200–250 km depth. On the contrary, a very bright low-velocity anomaly beneath the collision area implies that the lithosphere in this zone is very thin, which is also supported by strong horizontal deformations and crustal thickening indicating weak properties of the lithosphere. In the contact between stable continental and collision zones, we observe a rather complex alternation of seismic anomalies having the shapes of sinking drops. We propose that the convergence process causes crustal thickening and transformation of the lower crust material into the dense eclogite. When achieving a critical mass, the dense eclogitic drops trigger detachment of the mantle lithosphere and its delamination. The observed high-velocity bodies in the upper mantle may indicate the parts of the descending mantle lithosphere which were detached from the edges of the continental lithosphere plates. Very thin, or even absent, mantle parts of the lithosphere leads to the presence of hot asthenosphere just below the crust. The crustal shortening and eclogitisation of the lower crustal layer leads to the dominantly felsic composition of the crust which is favourable for the upward heat transport from the mantle. This, and also the factors of frictional heating and the radioactivity of felsic rocks, may be the origin of volcanic centres in the Caucasus and surrounding collisional areas.
Diverse Methodological Approaches and Considerations for SoTL in Higher Education
Authors: Hubball Harry , Clarke Anthony
Published: October 2012

The scholarship of teaching and learning (SoTL) is a distinctive form of research that is shaped by multi-disciplinary contexts and focuses on practice-driven institutional/curricula/classroom inquiries with an explicit transformational agenda. This essay provides critical insight to the importance of communities of SoTL practitioners, diverse investigations and methodological approaches within and across disciplines. For example, through an integrated and iterative process, a community of SoTL researchers plays a critical role to enhance and sustain on-going SoTL research. Equal to all forms of research endeavour, interpretations of SoTL research require a healthy scepticism, analysis of methodological rigour, and an openness to alternative perspectives and analysis.
L'avancement des connaissances en enseignement et apprentissage (ACEA) dans l'enseignement supérieur est une forme de recherche distinctive façonnée par des contextes multidisciplinaires. Axée sur la pratique, elle est centrée sur caractérisée par des enquêtes sur des institutions, des programmes d’enseignement et des classes, tout en axée sur la pratique et visant un objectif transformationnel explicite. Cet essai fournit un aperçu critique de l’importance des communautés d’intervenants de l’ACEA et des diverses enquêtes et approches méthodologiques au sein de chaque discipline et entre elles. Par exemple, grâce à un processus intégré et itératif, la communauté des chercheurs en ACEA joue un rôle essentiel en améliorant la recherche continue sur ce sujet et en la soutenant. Indépendamment du sujet considéré, l’interprétation de la recherche sur l’ACEA suppose de faire preuve d’un scepticisme sain, d’analyser la rigueur méthodologique et d’être ouvert aux autres perspectives et analyses.
Foundation Skills for Scientists: An Evolving Program
Authors: Dawson Teresa , Fedko Sarah , Johnston Nancy , Khoo Elaine , King Sarah , Mall Saira , Olaveson Mary , Patterson Janice , Persaud Kamini , Sardone Frances , Shahbazi Zohreh , Skene Allyson , Young Martha , Hasenkampf Clare A
Published: October 2012

We have undertaken an integrated and collaborative approach to developing foundational skills of students in a first year, Introductory Biology course. The course is a large lecture and laboratory course with enrollments ranging from 800-1000 per year. Teaching and Learning experts were brought into the course as weekly ‘Foundation Skills for Scientists’ sessions were created. The initial challenges were to have effective knowledge exchange between collaborators and create an integrated course syllabus. Once effective sessions were created, the next challenge was to improve student valuation of them. High value was only achieved when the skill sessions were tightly linked to course assignments and activities and was delivered ‘just in time’. Even then, the challenge has been to motivate students to realize that the sessions are directly relevant to them. Overall, student performance has improved since the program was initiated as measured by rate of retention in the course, overall course marks and quality of writing. Nous avons utilisé une approche intégrée et collaborative pour approfondir les compétences de base des étudiants de première année qui suivent un cours d’introduction à la biologie. Il s’agit d’un cours magistral et en laboratoire, auquel s’inscrivent entre 800 et 1000 étudiants par an. Ce cours a bénéficié de l’apport d’experts en enseignement et en apprentissage afin d’appuyer le développement de séances hebdomadaires portant sur les compétences de base en sciences. Les difficultés initiales étaient de susciter un échange de connaissances efficace entre les collaborateurs et de créer un plan de cours intégré. Une fois les séances organisées, la difficulté suivante a été de faire en sorte que les étudiants les apprécient davantage. Ces derniers les ont jugées très utiles uniquement lorsqu’elles étaient étroitement liées aux tâches et aux activités et lorsqu’elles étaient offertes au moment opportun. Même alors, le défi a consisté à motiver les étudiants afin qu’ils se rendent compte que les séances leur sont directement pertinentes. Dans l’ensemble, la performance des étudiants s’est améliorée depuis le début du programme comme l’indiquent les mesures du taux de persévérance dans le cours, les notes générales et la qualité de la rédaction.