bluuebunny/crossref_metadata_2025 huggingface dataset:
Severe Hypoglycemia and Cardiovascular Disease Incidence in Type 1 Diabetes
Authors: Gruden Gabriella , Barutta Federica , Chaturvedi Nish , Schalkwijk Casper , Stehouwer Coen D. , Witte Daniel R. , Fuller John H. , Cavallo Perin Paolo , Bruno Graziella
Published: May 2012

OBJECTIVE

Frequent episodes of severe hypoglycemia may increase the risk of cardiovascular disease (CVD) in people with diabetes. Our aim was to study the relationship between severe hypoglycemic episodes and CVD incidence in subjects with type 1 diabetes, and further, to assess if markers of inflammation/endothelial injury were enhanced in individuals who experienced hypoglycemic episodes.

RESEARCH DESIGN AND METHODS

The prospective study included 2,181 type 1 diabetic patients from the EURODIAB Prospective Complications Study. At baseline, frequency of self-reported severe hypoglycemia, defined as episodes serious enough to require the help of another person, was assessed based on responses to a patient questionnaire. Both fatal/nonfatal CVD was assessed 7.3 years after baseline examination. At the follow-up visit, data on both severe and nonsevere hypoglycemic episodes in the previous year were collected through a questionnaire and markers of inflammation/stress response/endothelial injury measured by enzyme-linked immunosorbent assays in the 531 subjects of the nested case-control study, including 363 case subjects with one or more complications of diabetes and 168 control subjects with no evidence of any complication.

RESULTS

During the follow-up period, 176 patients had incident CVD. Logistic regression analysis showed that severe hypoglycemia at the baseline examination was not associated with incidence of CVD (adjusted odds ratios [95% CI]: one to two episodes, 0.87 [0.55–1.37]; three or more episodes, 1.09 [0.68–1.75]). Furthermore, follow-up serum levels of markers of endothelial damage/inflammation were not cross-sectionally associated with the frequency of hypoglycemic episodes.

CONCLUSIONS

Taken together our data do not support the hypothesis that in type 1 diabetes, severe hypoglycemia increases the risk of CVD.
Analysis of Glucose Responses to Automated Insulin Suspension With Sensor-Augmented Pump Therapy
Authors: Ly Trang T. , Nicholas Jennifer A. , Retterath Adam , Davis Elizabeth A. , Jones Timothy W.
Published: May 2012

OBJECTIVE

The advent of sensor-augmented pump therapy with a low-glucose suspend (LGS) function (Medtronic Paradigm Veo System), allowing insulin to be automatically suspended for up to 2 h when sensor glucose falls below a preset threshold, has the potential to reduce the duration of hypoglycemia. In this article, we analyzed blood glucose profiles following a full 2-h insulin suspension activated by the LGS function, as well as examined different patterns of use among patients.

RESEARCH DESIGN AND METHODS

Data from a cohort of participants using the Veo System for up to 6 months were analyzed to determine the time and duration of insulin suspension activated by the LGS function. We further evaluated overnight suspend events with no patient response occurring prior to 3:00 a.m., which allowed us to determine the pattern of sensor glucose values with no patient intervention during and after the period of insulin suspension.

RESULTS

There were 3,128 LGS events during the 2,493 days evaluated. The median duration was 11.2 min, and 36% of events occurred overnight. There were 126 full 2-h suspend events that occurred overnight with no patient response, occurring before 3:00 a.m. For these events, the mean sensor glucose at the end of the 2-h suspend period was 99 ± 6 mg/dL ([means ± SE] 5.5 ± 0.3 mmol/L). The mean sensor glucose 2 h after insulin delivery resumed was 155 ± 10 mg/dL (8.6 ± 0.6 mmol/L). There were no episodes of severe hypoglycemia or diabetic ketoacidosis.

CONCLUSIONS

Analyses of sensor glucose patterns following insulin suspension activated by LGS suggest that this technology is safe and unlikely to be associated with adverse outcomes.
Lessons Learned from Inter-Professional Diabetes Educators in Diabetes Shared Medical Appointments
Authors: Watts Sharon A. , O'Day Mary Ellen , Pascuzzi-Frangella Kristina M.
Published: May 2012

In Brief

Diabetes educators have valued and unique skills in the art and science of diabetes management that are beneficial in the delivery of shared medical appointments (SMAs). These contributions augment and expand the medical model of intervention in chronic disease because psychosocial concerns and behavior change are integral to successful outcomes. This article reflects on lessons learned from a multidisciplinary team of diabetes health care professionals with a strong diabetes education background who have been delivering comprehensive diabetes care for more than 6 years in an SMA model.
Evaluating a Culturally and Linguistically Competent Health Coach Intervention for Chinese-American Patients With Diabetes
Authors: Ivey Susan L. , Tseng Winston , Kurtovich Elaine , Weir Rosy Chang , Liu Jing , Song Hui , Wang May , Hubbard Alan
Published: May 2012

Abstract

Background. Type 2 diabetes is a growing concern among medically underserved Chinese Americans. However, very few interventions have been developed or adapted for Chinese Americans with diabetes.

Objective. To use a participatory research approach to evaluate the effectiveness of a culturally tailored, linguistically appropriate model for diabetes care employing health coaches to improve A1C levels among Chinese-American patients in a federally qualified health center setting.

Methods. We compared change in A1C between intervention participants (n = 46), who received a health coaching intervention, and control participants (n = 46), who received usual care over a period of ~ 6 months.

Results. Intervention participants showed a decrease in mean A1C at follow-up (−0.40%) compared to control subjects (+0.04%), although this difference was not statistically significant. At the 6-month follow-up, a significantly higher percentage of intervention participants (45.7%) had well-controlled A1C levels compared to control subjects (23.9%) (P = 0.048).

Conclusions. It is feasible to implement a culturally tailored, linguistically appropriate teamlet model of care for Chinese Americans with type 2 diabetes. Such a model may be helpful in reducing A1C levels. Given trends in A1C improvement during a 6-month pilot, future randomized trials with a larger sample capable of providing adequate statistical power to detect improvements are warranted.
Finding Multiple Optimal Solutions to Optimal Load Distribution Problem in Hydropower Plant
Authors: Liu Pan , Nguyen Tri-Dung , Cai Ximing , Jiang Xinhao
Published: May 2012

Optimal load distribution (OLD) among generator units of a hydropower plant is a vital task for hydropower generation scheduling and management. Traditional optimization methods for solving this problem focus on finding a single optimal solution. However, many practical constraints on hydropower plant operation are very difficult, if not impossible, to be modeled, and the optimal solution found by those models might be of limited practical uses. This motivates us to find multiple optimal solutions to the OLD problem, which can provide more flexible choices for decision-making. Based on a special dynamic programming model, we use a modified shortest path algorithm to produce multiple solutions to the problem. It is shown that multiple optimal solutions exist for the case study of China’s Geheyan hydropower plant, and they are valuable for assessing the stability of generator units, showing the potential of reducing occurrence times of units across vibration areas.
Distributed Performance Measurement and Usability Assessment of the Tor Anonymization Network
Authors: Müller Sebastian , Brecht Franziska , Fabian Benjamin , Kunz Steffen , Kunze Dominik
Published: May 2012

While the Internet increasingly permeates everyday life of individuals around the world, it becomes crucial to prevent unauthorized collection and abuse of personalized information. Internet anonymization software such as Tor is an important instrument to protect online privacy. However, due to the performance overhead caused by Tor, many Internet users refrain from using it. This causes a negative impact on the overall privacy provided by Tor, since it depends on the size of the user community and availability of shared resources. Detailed measurements about the performance of Tor are crucial for solving this issue. This paper presents comparative experiments on Tor latency and throughput for surfing to 500 popular websites from several locations around the world during the period of 28 days. Furthermore, we compare these measurements to critical latency thresholds gathered from web usability research, including our own user studies. Our results indicate that without massive future optimizations of Tor performance, it is unlikely that a larger part of Internet users would adopt it for everyday usage. This leads to fewer resources available to the Tor community than theoretically possible, and increases the exposure of privacy-concerned individuals. Furthermore, this could lead to an adoption barrier of similar privacy-enhancing technologies for a Future Internet.
Isolation and Expression of Glucosinolate Synthesis Genes CYP83A1 and CYP83B1 in Pak Choi (Brassica rapa L. ssp. chinensis var. communis (N. Tsen & S.H. Lee) Hanelt)
Authors: Zhu Biao , Wang Zhizhou , Yang Jing , Zhu Zhujun , Wang Huasen
Published: May 2012

CYP83A1 and CYP83B1 are two key synthesis genes in the glucosinolate biosynthesis pathway. CYP83A1 mainly metabolizes the aliphatic oximes to form aliphatic glucosinolate and CYP83B1 mostly catalyzes aromatic oximes to synthesis corresponding substrates for aromatic and indolic glucosinolates. In this study, two CYP83A1 genes named BcCYP83A1-1 (JQ289997), BcCYP83A1-2 (JQ289996) respectively and one CYP83B1 (BcCYP83B1, HM347235) gene were cloned from the leaves of pak choi (Brassica rapa L. ssp. chinensis var. communis (N. Tsen & S.H. Lee) Hanelt) “Hangzhou You Dong Er” cultivar. Their ORFs were 1506, 1509 and 1500 bp in length, encoding 501, 502 and 499 amino acids, respectively. The predicted amino acid sequences of CYP83A1-1, CYP83A1-2 and CYP83B1 shared high sequence identity of 87.65, 86.48 and 95.59% to the corresponding ones in Arabidopsis, and 98.80, 98.61 and 98.80% to the corresponding ones in Brassica pekinensis (Chinese cabbage), respectively. Quantitative real-time PCR analysis indicated that both CYP83A1 and CYP83B1 expressed in roots, leaves and petioles of pak choi, while the transcript abundances of CYP83A1 were higher in leaves than in petioles and roots, whereas CYP83B1 showed higher abundances in roots. The expression levels of glucosinolate biosynthetic genes were consistent with the glucosinolate profile accumulation in shoots of seven cultivars and three organs. The isolation and characterization of the glucosinolate synthesis genes in pak choi would promote the way for further development of agronomic traits via genetic engineering.
Temperature Drift Compensation for Hemispherical Resonator Gyro Based on Natural Frequency
Authors: Wang Xu , Wu Wenqi , Fang Zhen , Luo Bing , Li Yun , Jiang Qingan
Published: May 2012

Temperature changes have a strong effect on Hemispherical Resonator Gyro (HRG) output; therefore, it is of vital importance to observe their influence and then make necessary compensations. In this paper, a temperature compensation model for HRG based on the natural frequency of the resonator is established and then temperature drift compensations are accomplished. To begin with, a math model of the relationship between the temperature and the natural frequency of HRG is set up. Then, the math model is written into a Taylor expansion expression and the expansion coefficients are calibrated through temperature experiments. The experimental results show that the frequency changes correspond to temperature changes and each temperature only corresponds to one natural frequency, so the output of HRG can be compensated through the natural frequency of the resonator instead of the temperature itself. As a result, compensations are made for the output drift of HRG based on natural frequency through a stepwise linear regression method. The compensation results show that temperature-frequency method is valid and suitable for the gyroscope drift compensation, which would ensure HRG’s application in a larger temperature range in the future.
Colloidal lithography for fabricating patterned polymer-brush microstructures
Authors: Chen Tao , Chang Debby P , Jordan Rainer , Zauscher Stefan
Published: May 2012

We exploit a series of robust, but simple and convenient colloidal lithography (CL) approaches, using a microsphere array as a mask or as a guiding template, and combine this with surface-initiated atom-transfer radical polymerization (SI-ATRP) to fabricate patterned polymer-brush microstructures. The advantages of the CL technique over other lithographic approaches for the fabrication of patterned polymer brushes are (i) that it can be carried out with commercially available colloidal particles at a relatively low cost, (ii) that no complex equipment is required to create the patterned templates with micro- and nanoscale features, and (iii) that polymer brush features are controlled simply by changing the size or chemical functionality of the microspheres or the substrate.
Qualitative Evaluation of the Canadian Fabry Disease Initiative
Authors: Embrett Mark , MacKinnon Neil J.
Published: May 2012

Background:

In late 2005, the federal and provincial governments responded to an increasing demand from physicians and their patients with Fabry disease for access to enzyme replacement therapy (ERT). This response took the form of a nationwide clinical research study, the Canadian Fabry Disease Initiative (CFDI). Patients who enrolled as participants in this longitudinal study received 1 of 2 ERT treatments. The present study used a qualitative evaluative approach to describe the perspectives of various key stakeholders regarding the CFDI and its potential as a model for providing access to expensive drugs for rare diseases.

Methods:

The CFDI was evaluated from the perspectives of 4 groups of key informants: patients, CFDI investigators, policy-makers and pharmaceutical manufacturers. The qualitative methods strategy used for the study involved semistructured interviews, a holistic-inductive design and content analysis.

Results:

Eighteen participants were interviewed. The study revealed that stakeholders held the following perceptions about the CFDI. The CFDI was created as a response to a drug reimbursement problem in Canada. Through specialist physicians, the CFDI has provided ERT to patients with Fabry disease across the country. The CFDI established a national database for collecting and monitoring the incidence of Fabry disease and information about ERT. The CFDI represented a collaborative effort among the various stakeholders (federal, provincial, pharmaceutical), but no stakeholder group thought that the CFDI was the correct response to the need for access to ERT. Finally, the CFDI can and should be redesigned, through modification of either its governing structure or its outcome goals.

Discussion:

The CFDI was a prototype for sharing the costs of expensive therapies for rare diseases. It has provided ERT to many patients with Fabry disease for several years. However, it was poorly designed to meet its outcome goals and has been unable to provide therapy to all individuals with the disease. Therefore, many stakeholders saw this initiative as an inappropriate solution.

Conclusions:

The CFDI has not met the expectations of key informant groups and some modifications may be necessary. A registry study might better accomplish the CFDI's original goals of providing access to treatment, gathering data and monitoring patients' progress.
Quitter l'Afghanistan : oui mais comment ?
Authors: Fuchs Gérard
Published: May 2012

Résumé Un retrait rapide d’Afghanistan est justifié selon Gérard Fuchs. Mais comment le conduire ? L’auteur préconise dans cet article l’organisation rapide d’une conférence réunissant tous les acteurs du drame afghan. Il dresse ainsi la liste des invités : les acteurs de terrain – le camp du Président Karzaï, les talibans et le Pakistan –, les acteurs de la périphérie – l’Inde, l’Iran et l’Arabie Saoudite –, et enfin les grandes puissances – les États-Unis, la Chine et la Russie –. Il analyse les intérêts et objectifs de ces acteurs et définit, à partir de ce puzzle d’intérêts contradictoires, les concessions nécessaires à la paix, auxquelles chacun d’eux, et principalement l’Afghanistan et le Pakistan, doit consentir. Selon lui, la France ne peut plus se contenter de s’aligner sur les décisions prises à Washington.
Evaluation and Treatment of Painful Total Hip Arthroplasties With Modular Metal Taper Junctions
Authors: Meneghini R. Michael , Hallab Nadim J. , Jacobs Joshua J.
Published: May 2012

Modern primary total hip arthroplasty femoral components have evolved to include modular necks. Subsequently, the additional taper junction provides another interface as a potential source for mechanically assisted crevice corrosion, which is a complex process involving fretting and crevice corrosion. Furthermore, it is becoming evident that an adverse local tissue reaction may result in some patients due to the mechanically assisted crevice corrosion. This article details the clinical, radiographic, and laboratory evaluation of patients with these components who present with persistent pain. The relevant surgical strategies and techniques to address this pathology in symptomatic patients are addressed.
Arthroscopic Bone Tunnel Augmentation for Rotator Cuff Repair
Authors: Garrigues Grant E. , Lazarus Mark D.
Published: May 2012

Transosseous repair of the rotator cuff has been shown to recreate the anatomic rotator cuff footprint in a secure and cost-efficient manner. However, the potential for sutures cutting through bone remains a concern with this strategy. Devices have been used successfully during open transosseous rotator cuff repair to augment the bone tunnels, potentially avoiding suture cut-out through the weak bone of the greater tuberosity. Recently, arthroscopic transosseous fixation of rotator cuff tears has become an alternative to arthroscopic suture anchor and open transosseous techniques. This method is expected to have the same potential pitfalls at the bone–suture interface as the open technique. The authors describe a technique for rotator cuff repair using a secure method of arthroscopic bone tunnel augmentation.
Analysis of NHSLA Claims in Orthopedic Surgery
Authors: Khan Irfan H. , Jamil Wiqqas , Lynn Sam Mathew , Khan Osman H. , Markland Kate , Giddins Grey
Published: May 2012

National Health Service (NHS) statistics in the United Kingdom demonstrate an increase in clinical negligence claims over the past 30 years. Reasons for this include elements of a cultural shift in attitudes toward the medical profession and the growth of the legal services industry. This issue affects medical and surgical health providers worldwide.

The authors analyzed 2117 NHS Litigation Authority (NHSLA) orthopedic surgery claims between 1995 and 2001 with respect to these clinical areas: emergency department, outpatient care, surgery (elective or trauma operations), and inpatient care. The authors focused on the costs of settling and defending claims, costs attributable to clinical areas, common causes of claims, and claims relating to elective or trauma surgery. Numbers of claims and legal costs increased most notably in surgery (elective and trauma) and in the emergency department. However, claims are being defended more robustly. The annual cost for a successful defense has remained relatively stable, showing a slight decline. The common causes of claims are postoperative complication; wrong, delayed, or failure of diagnosis; inadequate consent; and wrong-site surgery. Certain surgical specialties (eg, spine and lower-limb surgery) have the most claims made during elective surgery, whereas upper-limb surgery has the most claims made during trauma surgery.

The authors recommend that individual trusts liaise with orthopedic surgeons to devise strategies to address areas highlighted in our study. Despite differences in health care systems worldwide, the underlying issues are common. With improved understanding, physicians can deliver the service they promise their patients.
Osteoarticular Allograft Reconstruction for Hill-Sachs Lesion in an Adolescent
Authors: Nathan Senthil T. , Parikh Shital N.
Published: May 2012

Glenoid and humeral head bone loss is the most common cause of failure after surgical shoulder instability stabilization. Large Hill-Sachs lesions involving >30% of the articular surface of the humeral head typically occur after neglected or locked shoulder dislocations. Such large lesions may require osteochondral allograft reconstruction or prosthetic replacement to regain shoulder stability and function.

Previous reports of osteochondral allograft reconstruction have focused on adults. This article describes a case of a 16-year-old autistic boy who sustained an anterior dislocation of the right shoulder following a seizure episode. The dislocation was diagnosed 12 days later as a progressive deformity, and his parents noticed his inability to use his upper extremity. The patient had a large (30%) humeral head Hill-Sachs lesion and persistent anterior shoulder instability after initial closed reduction. He underwent an open osteochondral allograft reconstruction for the restoration of the humeral head articular surface. The sizing of the defect, matching harvest of the allograft, and perfect fit of the allograft to the defect are critical steps to ensure congruent restoration of the humeral head. The allograft was stabilized in the defect of the humeral head using cancellous screws placed from below the articular surface. Radiographs 20 months postoperatively showed complete incorporation of the osteochondral allograft. At 30 months postoperatively, his shoulder was stable and functional.
Prosthesis-free Solution for Below-knee Amputations
Authors: Lal Hitesh , Sharma Deepak Kumar , Mittal Deepak
Published: May 2012

The Ilizarov fixator can be used as a bone regenerator to correct limb-length discrepancies in patients who require limb lengthening.

A 17-year-old man presented with 12 cm of left lower-limb shortening and amputation at the left mid-forefoot region, which was the result of severe burns of the left lower limb at 2 years of age. The burns damaged the distal femoral, proximal, and distal tibial physes. Scarring around knee and leg acted as a bowstring and slowed normal longitudinal femoral and tibial bone growth. The patient wished to be prosthesis free. Limb lengthening was performed with the Ilizarov fixator. The patient became prosthesis free and was able to perform activities of daily living wearing normal footwear, which was possible because the patient had a good heel pad. The patient can walk on a normal limb with no prosthesis, the significant advantage being the right proprioceptive feedback it gives the patient during ambulation because it is sensate.

This technique can be used in other patients with below-knee amputations in which the tibial amputated end can be given a myoplasty cover or padding nearly as good as a heel. Subsequently, tibiae can be lengthened, and patients can be made to bear weight on artificial heels.
The Pedagogical Ebb and Flow of Human Patient Simulation: Empowering Through a Process of Fading Support
Authors: Parker Brian Corey , Myrick Florence
Published: May 2012

The use of the high-fidelity human patient simulator (HPS)-based clinical scenario in undergraduate nursing education is a powerful learning tool, well suited to modern nursing students’ preference for immersive construction of knowledge through the provision of contextually rich reality-based practice and social discourse. The purpose of this study was to explore the social–psychological processes that occur within HPS-based clinical scenarios. Grounded theory method was used to study students and faculty sampled from a Western Canadian baccalaureate nursing program. The process of leveled coding generated a substantive theory that has the potential to enable educators to empower students through the use of fading support, a twofold process composed of adaptive scaffolding and dynamic assessment that challenges students to realistically self-regulate and transform their frame of reference for nursing practice, while limiting the threats that traditional HPS-based curriculum can impose.
Dietary Supplement Drug Therapies for Depression
Authors: Howland Robert H.
Published: May 2012

Many dietary supplements are readily accessible and commonly used for the treatment of depression. A dietary supplement is a product intended to supplement the diet but is not intended to treat, diagnose, prevent, or cure disease. The U.S. Food and Drug Administration can take action against dietary supplement manufacturers for products only after they are marketed, mainly if the product is found to be unsafe or if false or misleading claims are made about the product. Few dietary supplement products have been adequately studied for their safety and efficacy. Of the five products reviewed in this article (L-methylfolate, S-adenosyl-L-methionine [SAM-e], omega-3 fatty acids, L-tryptophan, and inositol), only omega-3 fatty acids and SAM-e have sufficient supporting evidence for their efficacy to warrant safe use.
Central Corneal Volume and Endothelial Cell Count Following Femtosecond Laser–assisted Refractive Cataract Surgery Compared to Conventional Phacoemulsification
Authors: Takács Ágnes I. , Kovács Illés , Miháltz Kata , Filkorn Tamás , Knorz Michael C. , Nagy Zoltán Z.
Published: May 2012

PURPOSE:

To compare the effect of conventional phacoemulsification and femtosecond laser–assisted cataract surgery on the cornea using Scheimpflug imaging and noncontact specular microscopy.

METHODS:

In each group, 38 eyes (38 patients) underwent cataract surgery using either femtosecond laser–assisted (Alcon LenSx laser) (femtolaser group) or conventional phacoemulsification (phaco group). Central corneal thickness, 3-mm corneal volume, and Pentacam Nucleus Staging (PNS) were determined by a rotating Scheimpflug camera (Pentacam HR, Oculus Optikgeräte GmbH), and the volume stress index was calculated at 1 day and 1 month postoperatively. Endothelial cell count was measured by noncontact specular microscopy preoperatively, 1 day, 1 week, and 1 month postoperatively.

RESULTS:

Central corneal thickness was significantly higher in the phaco group (607±91 μm) than in the femtolaser group (580±42 μm) on day 1, but did not differ significantly preoperatively and at 1 week and 1 month. Volume stress index at day 1 was significantly lower in the femtolaser group than in the phaco group (
P
<.05) but did not differ significantly at 1 month. Multivariate regression analysis showed that the type of surgery had a significant effect on central corneal thickness.

CONCLUSIONS:

Femtosecond laser–assisted cataract surgery causes less corneal swelling in the early postoperative period and may cause less trauma to corneal endothelial cells than manual phacoemulsification.
Cultural History and its Neighbours
Authors: Burke Peter
Published: May 2012

This article offers a kind of map of intellectual fields that are more or less close to cultural history. It is difficult to separate cultural history from intellectual, social and political history, from archaeology and from the histories of such activities as art, literature, language and religion, whether these histories are studied in departments of history or under the umbrella of “visual studies”, “religious studies” or “cultural studies”. All these neighbours form an “inner circle”, discussed in relative detail. Beyond it lies a “middle circle” of disciplines that are separate from cultural history but have made considerable impact on it: anthropology, ethnology, sociology, politics and geography. Still further away, and discovered by cultural historians only recently, comes an “outer circle”, comprising psychology, cognitive studies, neuroscience and biology. The effect of the outer circle of disciplines on the practice of cultural history remains uncertain.
Retinal Vasculitis in Systemic Lupus Erythematosus: An Indication of Active Disease
Authors: Md Noh Umi Kalthum , Zahidin Aida Zairani A. , Yong Then Kong
Published: May 2012

A 26-year-old woman with a recent flare-up of systemic lupus erythematosus presented with peripheral retinal hemorrhages at a routine check-up. She is on a tapering dose of immunosuppressive agents. Her visual acuity was good. Fluorescein angiogram revealed vasculitic changes with capillary non-perfusion areas. A few weeks later, she developed cerebral lupus with advanced lupus nephritis. Immunosuppressive therapy was restarted and panretinal photocoagulation was delivered. Her visual acuity remained stable, despite development of a cataract from prednisolone therapy.
Prevalence of bovine trypanosomosis and its vectors in two districts of East Wollega Zone, Ethiopia
Authors: Tafese Wagari , Melaku Achenef , Fentahun Tewodros
Published: May 2012

Trypanosomosis is a parasitic disease that causes serious economic losses in livestock, especially in sub-Saharan countries. This study was conducted from October 2010 to March 2011 in the Diga and Sasiga districts of the East Wollega zone in western Ethiopia to determine the prevalence of bovine trypanosomosis and its vectors. A total of 386 blood samples were collected from randomly selected animals. Packed cell volume (PCV) was determined and samples were examined for the presence of trypanosomes using the buffy coat technique. Out of 386 blood samples, 8.55% tested positive for trypanosomes. The majority of the infections were caused by Trypanosoma congolense (72.73%), followed by Trypanosoma vivax (27.27%). There were no statistically significant differences (p > 0.05) between districts, altitudes, sexes and ages, but the prevalence was significantly higher (p < 0.05) in cattle which were in poor body condition. The mean PCV value of infected animals (21.45 ± 3.62 s.d.) was significantly lower (p < 0.05) than that of non-infected animals (26.60 ± 4.60 s.d.). A total of 1151 flies were caught by deploying 21 monoconical shaped traps. Of these flies, 822 (71.42%) were Glossina, whilst the remaining flies were either Stomoxys (17.20%) or Tabanus (11.38%). The overall apparent densities of tsetse and biting flies were 1.45 and 0.58 flies per trap per day, respectively. In conclusion, this study confirmed that trypanosomes and their vectors are prevalent and still pose a threat to cattle production in the area. Therefore, proper strategies have to be designed and implemented to minimise their effect on livestock production.
Coral species richness estimates are sensitive to differences in reef size and regional diversity
Authors: Huntington Brittany E. , Lirman Diego
Published: May 2012

Estimates of species richness have been used to assess how community diversity changes across space and time. Here, we elucidate the bias that can arise when applying a popular sampling method (i.e., fixed number of belt‐transects) to census coral community richness when the size of the reef and the regional species pools vary. Based on surveys of 148 patch reefs in 3 sub‐regions of the Western Atlantic, we show that a fixed subsampling approach underestimated coral species richness of the reef as reef size increased; though this bias is minor for the entire region. The percentage of the true reef richness captured by sub‐sampled transects declined by 6% for every 10‐fold change in reef size. However, in Belize, the most speciose sub‐region sampled, coral richness was underestimated by 15% solely as a result of a 10‐fold increase in reef size. Increasing sampling effort (nr of transects) per reef was not able to correct for this underestimation. Furthermore, we demonstrate that this sampling bias is not an artifact of larger reefs simply being more diverse, and hence, requiring greater sampling efforts. Rather, these results suggest that coral species in diverse regions are distributed in accordance with the variety of spatially structured microhabitats present on a reef, rather than distributing randomly across the reef surface. Furthermore, these patterns seem to be highly scale‐dependent. As such, sampling protocols should consider the size of the reef to be surveyed as well as the regional species pool to ensure accurate estimates of coral diversity.
Estimation of speciated and total mercury dry deposition at monitoring locations in eastern and central North America
Authors: Zhang L. , Blanchard P. , Gay D. A. , Prestbo E. M. , Risch M. R. , Johnson D. , Narayan J. , Zsolway R. , Holsen T. M. , Miller E. K. , Castro M. S. , Graydon J. A. , Louis V. L. St. , Dalziel J.
Published: May 2012

Abstract. Dry deposition of speciated mercury, i.e., gaseous oxidized mercury (GOM), particulate-bound mercury (PBM), and gaseous elemental mercury (GEM), was estimated for the year 2008–2009 at 19 monitoring locations in eastern and central North America. Dry deposition estimates were obtained by combining monitored two- to four-hourly speciated ambient concentrations with modeled hourly dry deposition velocities (Vd) calculated using forecasted meteorology. Annual dry deposition of GOM+PBM was estimated to be in the range of 0.4 to 8.1 μg m−2 at these locations with GOM deposition being mostly five to ten times higher than PBM deposition, due to their different modeled Vd values. Net annual GEM dry deposition was estimated to be in the range of 5 to 26 μg m−2 at 18 sites and 33 μg m−2 at one site. The estimated dry deposition agrees very well with limited surrogate-surface dry deposition measurements of GOM and PBM, and also agrees with litterfall mercury measurements conducted at multiple locations in eastern and central North America. This study suggests that GEM contributes much more than GOM+PBM to the total dry deposition at the majority of the sites considered here; the only exception is at locations close to significant point sources where GEM and GOM+PBM contribute equally to the total dry deposition. The relative magnitude of the speciated dry deposition and their good comparisons with litterfall deposition suggest that mercury in litterfall originates primarily from GEM, which is consistent with the limited number of previous field studies. The study also supports previous analyses suggesting that total dry deposition of mercury is equal to, if not more important than, wet deposition of mercury on a regional scale in eastern North America.
Hindcast experiments of tropospheric composition during the summer 2010 fires over western Russia
Authors: Huijnen V. , Flemming J. , Kaiser J. W. , Inness A. , Leitão J. , Heil A. , Eskes H. J. , Schultz M. G. , Benedetti A. , Hadji-Lazaro J. , Dufour G. , Eremenko M.
Published: May 2012

Abstract. The severe wildfires in western Russia during July–August 2010 coincided with a strong heat wave and led to large emissions of aerosols and trace gases such as carbon monoxide (CO), hydrocarbons and nitrogen oxides into the troposphere. This extreme event is used to evaluate the ability of the global MACC (Monitoring Atmospheric Composition and Climate) atmospheric composition forecasting system to provide analyses of large-scale pollution episodes and to test the respective influence of a priori emission information and data assimilation on the results. Daily 4-day hindcasts were conducted using assimilated aerosol optical depth (AOD), CO, nitrogen dioxide (NO2) and ozone (O3) data from a range of satellite instruments. Daily fire emissions were used from the Global Fire Assimilation System (GFAS) version 1.0, derived from satellite fire radiative power retrievals. The impact of accurate wildfire emissions is dominant on the composition in the boundary layer, whereas the assimilation system influences concentrations throughout the troposphere, reflecting the vertical sensitivity of the satellite instruments. The application of the daily fire emissions reduces the area-average mean bias by 63% (for CO), 60% (O3) and 75% (NO2) during the first 24 h with respect to independent satellite observations, compared to a reference simulation with a multi-annual mean climatology of biomass burning emissions. When initial tracer concentrations are further constrained by data assimilation, biases are reduced by 87, 67 and 90%. The forecast accuracy, quantified by the mean bias up to 96 h lead time, was best for all compounds when using both the GFAS emissions and assimilation. The model simulations suggest an indirect positive impact of O3 and CO assimilation on hindcasts of NO2 via changes in the oxidizing capacity. However, the quality of local hindcasts was strongly dependent on the assumptions made for forecasted fire emissions. This was well visible from a relatively poor forecast accuracy quantified by the root mean square error, as well as the temporal correlation with respect to ground-based CO total column data and AOD. This calls for a more advanced method to forecast fire emissions than the currently adopted persistency approach. The combined analysis of fire radiative power observations, multiple trace gas and aerosol satellite observations, as provided by the MACC system, results in a detailed quantitative description of the impact of major fires on atmospheric composition, and demonstrate the capabilities for the real-time analysis and forecasts of large-scale fire events.
On the interpretation of an unusual in-situ measured ice crystal scattering phase function
Authors: Baran A. J. , Gayet J.-F. , Shcherbakov V.
Published: May 2012

Abstract. In-situ Polar Nephelometer (PN) measurements of unusual ice crystal scattering phase functions were recently reported by Gayet et al. (2012). The ice crystal habits that produced the phase functions were small chain-like aggregates, which had on their surfaces, smaller quasi-spherical ice crystals. The measured-averaged phase functions were featureless, at scattering angles less than about 100°, but an ice bow-like feature was noted between the scattering angles of about 120° to 160°. The estimated asymmetry parameter was 0.78 ± 0.04. In this paper, the phase function is interpreted in terms of a weighted habit mixture model. The best-fit model comprises of highly distorted ten element hexagonal ice aggregates, and the smaller quasi-spherical ice crystals are represented by Chebyshev ice particles. The weighted mean asymmetry parameter was found to be 0.81. It is argued that the Chebyshev-like ice particles are responsible for the ice bow-like feature and mostly dominate the scattered intensity measured by the PN. The results of this paper have important implications for climate modelling (energy balance of anvils) and the remote sensing of cirrus properties.
Ship emissions of SO2 and NO2: DOAS measurements from airborne platforms
Authors: Berg N. , Mellqvist J. , Jalkanen J.-P. , Balzani J.
Published: May 2012

Abstract. A unique methodology to measure gas fluxes of SO2 and NO2 from ships using optical remote sensing is described and demonstrated in a feasibility study. The measurement system is based on Differential Optical Absorption Spectroscopy using reflected skylight from the water surface as light source. A grating spectrometer records spectra around 311 nm and 440 nm, respectively, with the telescope pointed downward at a 30° angle from the horizon. The mass column values of SO2 and NO2 are retrieved from each spectrum and integrated across the plume. A simple geometric approximation is used to calculate the optical path. To obtain the total emission in kg h−1 the resulting total mass across the plume is multiplied with the apparent wind, i.e. a dilution factor corresponding to the vector between the wind and the ship speed. The system was tested in two feasibility studies in the Baltic Sea and Kattegat, from a CASA-212 airplane in 2008 and in the North Sea outside Rotterdam from a Dauphin helicopter in an EU campaign in 2009. In the Baltic Sea the average SO2 emission out of 22 ships was (54 ± 13) kg h−1, and the average NO2 emission was (33 ± 8) kg h−1, out of 13 ships. In the North Sea the average SO2 emission out of 21 ships was (42 ± 11) kg h−1, NO2 was not measured here. The detection limit of the system made it possible to detect SO2 in the ship plumes in 60% of the measurements when the described method was used. A comparison exercise was carried out by conducting airborne optical measurements on a passenger ferry in parallel with onboard measurements. The comparison shows agreement of (−30 ± 14)% and (−41 ± 11)%, respectively, for two days, with equal measurement precision of about 20%. This gives an idea of the measurement uncertainty caused by errors in the simple geometric approximation for the optical light path neglecting scattering of the light in ocean waves and direct and multiple scattering in the exhaust plume under various conditions. A tentative error budget indicates uncertainties within 30–45% but for a reliable error analysis the optical light path needs to be modelled. A ship emission model, FMI-STEAM, has been compared to the optical measurements showing an 18% overestimation and a correlation coefficient (R2) of 0.6. It is shown that a combination of the optical method with modelled power consumption can estimate the sulphur fuel content within 40%, which would be sufficient to detect the difference between ships running at 1% and at 0.1%, limits applicable within the IMO regulated areas.
A new method for total OH reactivity measurements using a fast Gas Chromatographic Photo-Ionization Detector (GC-PID)
Authors: Nölscher A. C. , Sinha V. , Bockisch S. , Klüpfel T. , Williams J.
Published: May 2012

Abstract. The primary and most important oxidant in the atmosphere is the hydroxyl radical (OH). Currently OH sinks, particularly gas phase reactions, are poorly constrained. One way to characterize the overall sink of OH is to measure directly the ambient loss rate of OH, the total OH reactivity. To date direct measurements of total OH reactivity have been either performed using a Laser Induced Fluorescence (LIF) system ("pump-and-probe" or "flow reactor") or the Comparative Reactivity Method (CRM) with a Proton Transfer Reaction Mass Spectrometer (PTR-MS). Both techniques require large, complex and expensive detection systems. This study presents a feasibility assessment for CRM total OH reactivity measurements using a new detector, a Gas Chromatographic Photo-Ionization Detector (GC-PID). Such a system is smaller, more portable, less power consuming and less expensive than other total OH reactivity measurement techniques. Total OH reactivity is measured by the CRM using a competitive reaction between a reagent (here pyrrole) with OH alone and in the presence of atmospheric reactive molecules. The new CRM method for total OH reactivity has been tested with parallel measurements of the GC-PID and the previously validated PTR-MS as detector for the reagent pyrrole during laboratory experiments, plant chamber and boreal field studies. Excellent agreement of both detectors was found when the GC-PID was operated under optimum conditions. Time resolution (60–70 s), sensitivity (LOD 3–6 s−1) and overall uncertainty (25% in optimum conditions) for total OH reactivity were equivalent to PTR-MS based total OH reactivity measurements. One drawback of the GC-PID system was the steady loss of sensitivity and accuracy during intensive measurements lasting several weeks, and a possible toluene interference. Generally, the GC-PID system has been shown to produce closely comparable results to the PTR-MS and thus in suitable environments (e.g. forests) it presents a viably economical alternative for groups interested in total OH reactivity observations.
Production, partitioning and stoichiometry of organic matter under variable nutrient supply during mesocosm experiments in the tropical Pacific and Atlantic Ocean
Authors: Franz J. M. S. , Hauss H. , Sommer U. , Dittmar T. , Riebesell U.
Published: May 2012

Abstract. Oxygen-deficient waters in the ocean, generally referred to as oxygen minimum zones (OMZ), are expected to expand as a consequence of global climate change. Poor oxygenation is promoting microbial loss of inorganic nitrogen (N) and increasing release of sediment-bound phosphate (P) into the water column. These intermediate water masses, nutrient-loaded but with an N deficit relative to the canonical N:P Redfield ratio of 16:1, are transported via coastal upwelling into the euphotic zone. To test the impact of nutrient supply and nutrient stoichiometry on production, partitioning and elemental composition of phytoplankton-derived dissolved (DOC, DON, DOP) and particulate (POC, PON, POP) organic matter, three nutrient enrichment experiments were conducted with natural phytoplankton communities in shipboard mesocosms, during research cruises in the tropical waters of the South East Pacific and the North East Atlantic. Maximum accumulation of POC and PON was observed under high N supply conditions, indicating that primary production was controlled by N availability. The stoichiometry of photoautotrophic biomass was unaffected by nutrient N:P supply during exponential growth under nutrient saturation, while it was highly variable under conditions of nutrient limitation and closely correlated to the N:P supply ratio, although PON:POP of accumulated phytoplankton generally exceeded the supply ratio. Phytoplankton N:P composition was constrained by a general lower limit of 5:1. Channelling of assimilated P into DOP appears to be the mechanism responsible for the consistent offset of cellular stoichiometry relative to inorganic nutrient supply and nutrient drawdown, as DOP build-up was observed to intensify under decreasing N:P supply. Low nutrient N:P conditions in coastal upwelling areas overlying O2-deficient waters seem to represent a net source for DOP, which may stimulate growth of diazotrophic phytoplankton. These results demonstrate that microalgal nutrient assimilation and partitioning of phytoplankton-derived organic matter between the particulate and the dissolved phase are controlled by the N:P ratio of upwelled nutrients, implying substantial consequences for nutrient cycling and organic matter pools in the course of decreasing nutrient N:P stoichiometry.