bluuebunny/crossref_metadata_2025 huggingface dataset:
Toxic effects and antitumor response of gemcitabine in combination with piroxicam treatment in dogs with transitional cell carcinoma of the urinary bladder
Authors: Marconato Laura , Zini Eric , Lindner Donna , Suslak-Brown Lisa , Nelson Victoria , Jeglum Ann K.
Published: April 2011

Objective—To investigate whether combined treatment with gemcitabine and piroxicam in dogs with transitional cell carcinoma (TCC) of the urinary bladder is tolerated and provides an advantage in terms of survival time over previously reported treatments.

Design—Clinical trial.

Animals—38 dogs with TCC of the urinary bladder.

Procedures—Dogs were treated with gemcitabine (800 mg/m2, IV over 30 to 60 minutes, q 7 d) and piroxicam (0.3 mg/kg [0.14 mg/lb], PO, q 24 h). Complete blood cell counts were monitored prior to each gemcitabine treatment. All toxic effects of gemcitabine in dogs were recorded. Primary tumors were ultrasonographically reevaluated after 4 gemcitabine treatments.

Results—Dogs received a median of 8 gemcitabine treatments (range, 1 to 38 treatments/dog). In response to treatment, 10 of 38 (26.3%) dogs had grade 1 gastrointestinal tract signs, 11 (28.9%) had grade 2, and 5 (13.2%) had grade 3. Grade 1 neutropenia developed in 6 (15.8%) dogs and grade 2 and 3 neutropenia in 2 (5.3%) dogs each. Thrombocytopenia was rare. All dogs had improvement of clinical signs of disease. Two dogs had a complete tumor response, 8 had a partial response, 19 had stable disease, and 8 had progressive disease. Median survival time with treatment was 230 days.

Conclusions and Clinical Relevance—Administration of gemcitabine in combination with piroxicam treatment failed to provide a longer overall survival time in dogs with TCC of the urinary bladder, compared with previously reported treatment strategies. However, this combination of chemotherapy did provide a new treatment alternative with fewer adverse effects.
Association of hypertriglyceridemia with insulin resistance in healthy Miniature Schnauzers
Authors: Xenoulis Panagiotis G. , Levinski Melinda D. , Suchodolski Jan S. , Steiner Jörg M.
Published: April 2011

Objective—To determine whether hypertriglyceridemia in Miniature Schnauzers is associated with insulin resistance.

Design—Case-control study.

Animals—28 Miniature Schnauzers with hypertriglyceridemia and 31 Miniature Schnauzers for which serum triglyceride concentrations were within the reference range (control dogs).

Procedures—All dogs had no history of chronic disease, were free of clinical signs for at least 3 months prior to blood collection, and were not receiving any medications known to affect lipid metabolism or serum insulin concentration. Food was withheld from each dog for ≥ 12 hours; a 5- to 10-mL blood sample was collected and allowed to clot to obtain serum. Serum insulin and glucose concentrations were measured, and the homeostasis model assessment (HOMA) score was calculated (ie, [basal serum insulin concentration {mU/L} × basal serum glucose concentration {mmol/L}]/22.5).

Results—Median serum insulin concentration was significantly higher in hypertriglyceridemic Miniature Schnauzers (21.3 mU/L) than it was in control dogs (12.5 mU/L). The percentage of dogs with high serum insulin concentrations was significantly greater in the hypertriglyceridemic group (28.6%) than it was in the control group (6.5%; odds ratio, 5.8; 95% confidence interval, 1.1 to 30.2). Median HOMA score for hypertriglyceridemic Miniature Schnauzers (4.9) was significantly higher than that for control dogs (2.8).

Conclusions and Clinical Relevance—Results indicated that hypertriglyceridemia in Miniature Schnauzers is often associated with insulin resistance. Further studies are needed to determine the prevalence and clinical importance of insulin resistance in hypertriglyceridemic Miniature Schnauzers.
Description and genetic analysis of three sets of monozygotic twins resulting from transfers of single embryos to recipient mares
Authors: Mancill Semira S. , Blodgett Glenn , Arnott Robert J. , Alvarenga Marco , Love Charles C. , Hinrichs Katrin
Published: April 2011

Case Description—3 sets of monozygotic twins resulting from transfers of single embryos to recipient mares were examined.

Clinical Findings—In all 3 recipient mares with twin pregnancies, only 1 embryonic vesicle was detected before day 25 of gestation. In 1 recipient mare, 2 apparent adjacent vesicles, each containing an embryo with a heartbeat, were visualized on ultrasonographic examination on day 37 of gestation. The other 2 recipient mares underwent ultrasonographic examination on day 30 of gestation, at which time only 1 vesicle and embryo was identified. In these latter 2 recipient mares, however, a thorough ultrasonographic examination for a second conceptus on day 30 had not been performed, as only 1 embryo had been transferred and visualized on early ultrasonographic examination.

Treatment and Outcome—All twin pregnancies resulted in death of both fetuses. Genetic analysis confirmed that each set of monozygotic twins originated from the transferred embryo.

Clinical Relevance—Monozygotic twin pregnancy may occur after embryo transfer; thus recipient mares should be examined thoroughly for multiple conceptuses, especially between 25 and 30 days of gestation. At this time, the allantoides of monozygotic twins should be visible ultrasonographically and effective management may still be possible.
Intra- and interobserver variability of board-certified veterinary radiologists and veterinary general practitioners for pulmonary nodule detection in standard and inverted display mode images of digital thoracic radiographs of dogs
Authors: Reese David J. , Green Eric M. , Zekas Lisa J. , Flores Jane E. , Hill Lawrence N. , Winter Matthew D. , Berry Clifford R. , Ackerman Norman
Published: April 2011

Objective—To determine intra- and interobserver variability of 2 veterinary radiologists and 2 veterinary general practitioners for detection of pulmonary nodules in standard and inverted (reversed grayscale) displays of digital thoracic radiographs of dogs.

Design—Evaluation study.

Sample—114 sets of 3-view (right lateral, left lateral, and ventrodorsal or dorsoventral views) digital thoracic radiographs from 114 dogs.

Procedures—2 experienced board-certified veterinary radiologists and 2 experienced veterinary general practitioners individually evaluated 114 randomized sets of radiographs. Pulmonary nodules were present in radiographs of 60 of 114 dogs. Each reviewer examined all images in standard or inverted display mode and scored nodule detection on a confidence scale of 1 to 5. After ≥ 2 months, the same individuals evaluated the same images in the remaining display mode. Intraobserver agreement for each display mode was determined via a κ statistic; results between the 2 groups of reviewers were compared via receiver operator curve analysis.

Results—There was no significant intraobserver variability in pulmonary nodule detection between the 2 display modes. Detection accuracy for board-certified radiologists was significantly greater than that of veterinary general practitioners for both display modes. Near-perfect intraobserver agreement was detected between the 2 display modes for board-certified radiologists, whereas moderate to slight intraobserver agreement was detected for the veterinary general practitioners.

Conclusions and Clinical Relevance—Detection of pulmonary nodules in digital thoracic radiographs was comparable, whether a standard or inverted mode was used for evaluations. However, the board-certified radiologists had greater detection accuracy than did veterinary general practitioners.
Spine-shortening osteotomy for patients with tethered cord syndrome caused by lipomyelomeningocele
Authors: Kokubun Shoichi , Ozawa Hiroshi , Aizawa Toshimi , Ly Ngo Minh , Tanaka Yasuhisa
Published: April 2011

Object

Tethered cord syndrome (TCS) is a disorder involving an abnormal stretching of the tethered spinal cord caused by several pathological conditions and presents with a variety of neurological symptoms. Untethering (tethered cord release) is the gold standard treatment for TCS. However, untethering carries risks of spinal cord injury and postoperative retethering. To avoid these potential risks, the authors applied spine-shortening osteotomy to adult patients with TCS, and report on the surgical procedure and treatment outcomes.

Methods

Eight patients with TCS caused by a lipomyelomeningocele were surgically treated by the authors' original procedure of spine-shortening osteotomy. Six patients were male and 2 were females; average age at the time of surgery was 31 years old. Spine-shortening osteotomy was performed at the level of L-1 in all but 2 patients, in whom it was performed at T-12, with spinal fusion between T-12 and L-2 or T-11 and L-1 using a pedicle screw–rod system. The average follow-up period was 6.2 years and the patients' pre- and postoperative conditions were evaluated clinically and radiologically.

Results

Preoperatively, all patients displayed severe neurological deficits such as motor disturbance, muscle atrophy, and bladder dysfunction. Several months before surgery, all showed progressive symptoms. Those symptoms showed initial improvement in 6 patients and stabilized in 2 postoperatively, but the improved symptoms worsened again in 4 of the 6 patients. The osteotomized vertebrae were shortened by 21 mm on average, and all spines showed complete bone union without loss of correction. At the final follow-up evaluations, 6 patients showed stabilization as per the modified Japanese Orthopaedic Association score for thoracic myelopathy.

Conclusions

Spine-shortening osteotomy successfully helps reduce the spinal cord tension without causing direct neural damage. At minimum, it stabilized the patients' symptoms and/or helped delay neurological deterioration for a period of time. Spine-shortening osteotomy might be a feasible mode of treatment for adult TCS caused by a spinal lipoma.
Frameless deep brain stimulation using intraoperative O-arm technology
Authors: Smith Adam P. , Bakay Roy A. E.
Published: April 2011

Object

Correct lead location in the desired target has been proven to be a strong influential factor for good clinical outcome in deep brain stimulation (DBS) surgery. Commonly, a surgeon's first reliable assessment of such location is made on postoperative imaging. While intraoperative CT (iCT) and intraoperative MR imaging have been previously described, the authors present a series of frameless DBS procedures using O-arm iCT.

Methods

Twelve consecutive patients with 15 leads underwent frameless DBS placement using electrophysiological testing and O-arm iCT. Initial target coordinates were made using standard indirect and direct assessment. Microelectrode recording (MER) with kinesthetic responses was performed, followed by microstimulation to evaluate the side-effect profile. Intraoperative 3D CT acquisitions obtained between each MER pass and after final lead placement were fused with the preoperative MR image to verify intended MER movements around the target area and to identify the final lead location. Tip coordinates from the initial plan, final intended target, and actual lead location on iCT were later compared with the lead location on postoperative MR imaging, and euclidean distances were calculated. The amount of radiation exposure during each procedure was calculated and compared with the estimated radiation exposure if iCT was not performed.

Results

The mean euclidean distances between the coordinates for the initial plan, final intended target, and actual lead on iCT compared with the lead coordinates on postoperative MR imaging were 3.04 ± 1.45 mm (p = 0.0001), 2.62 ± 1.50 mm (p = 0.0001), and 1.52 ± 1.78 mm (p = 0.0052), respectively. The authors obtained good merging error during image fusion, and postoperative brain shift was minimal. The actual radiation exposure from iCT was invariably less than estimates of exposure using standard lateral fluoroscopy and anteroposterior radiographs (p < 0.0001).

Conclusions

O-arm iCT may be useful in frameless DBS surgery to approximate microelectrode or lead locations intraoperatively. Intraoperative CT, however, may not replace fundamental DBS surgical techniques such as electrophysiological testing in movement disorder surgery. Despite the lack of evidence for brain shift from the procedure, iCT-measured coordinates were statistically different from those obtained postoperatively, probably indicating image merging inaccuracy and the difficulties in accurately denoting lead location. Therefore, electrophysiological testing may truly be the only means of precisely knowing the location in 3D space intraoperatively. While iCT may provide clues to electrode or lead location during the procedure, its true utility may be in DBS procedures targeting areas where electrophysiology is less useful. The use of iCT appears to reduce radiation exposure compared with the authors' traditional frameless technique.
Undergraduate Medical Education in Bangladesh: Facts & Challenges
Authors: Rahman Md Mahfuzar
Published: April 2011

DOI: 10.3329/akmmcj.v1i1.7451Anwer Khan Modern Medical College Journal 2010; 1(1): 03
A Study on Pattern of Alleged Rape Cases at SBMC, Barisal
Authors: Barek Abdul
Published: April 2011

Rape is a common social problem having great implication on the Victim, family, Judiciary and state. However it is very difficult to prove the actual rape because it is difficult to establish whether it is a consented sex or actual rape. 176 cases of alleged rape were studied during the period of 2003-2006 at the SBMC, Barisal. Of these, 130 cases had consented sexual intercourse. 46 victims were subjected to rape. Cases include different age groups, their occupations, living areas, time of arrival for medicolegal examination have been studied. Most of the cases were students. An alarming number of victims were subjected to gang rape. Examination and reporting of the cases with have been discussed. Key Words: Alleged Rape; Pattern; Consented Sex; Gang rape DOI: 10.3329/akmmcj.v1i1.7454 Anwer Khan Modern Medical College Journal 2010; 1(1): 15-18
Obesity and Disease Association: A Review
Authors: Sarnali Tanjila Tahmin , PK Md Moyenuddin
Published: April 2011

Obesity is a major public health problem which is not only confined to developed countries but has now become an important public health problem in developing countries like Bangladesh also. High calorie intake in diet due to increased consumption of refined sugars, sweetened beverages, vegetable oils, chunk and fast food and lack of physical activity, absence of play ground (open-spaces), sedantery life style all play a role in the development of obesity. Excess adiposity also known as obesity and excess body weight are associated with increased association with different types of diseases like type 2 diabetes, dyslipidemias, cardiovascular disease, hypertension and cancer. This review article highlights the pathogenesis, disease association with obesity. Key words: Obesity; Disease Association; Public Health Problem DOI: 10.3329/akmmcj.v1i2.7461 Anwer Khan Modern Medical College Journal 2010; 1(2): 21-24
GFR and Cardiovascular Events in Type 2 Diabetes Mellitus
Authors: Zabeen S , Rahman MR , Nargis W , Mustafa TG , Eusufzai NH
Published: April 2011

Individual with type 2 diabetes is a high risk group for both adverse cardiac as well as renal events. GFR is an independent predictor of cardiovascular morbidity and mortality. Reduced GFR is associated with a high prevalence of cardiovascular risk factors and higher prevalence of cardiovascular disease. The study was designed to explore the association between reduced GFR and cardiovascular events in diabetic subjects. It was a case-control study. One hundred and twenty nine (129) male subjects with cardiac event or events were selected. Diabetes of them 50 was type 2 and 79 were non diabetic. Modification of diet in renal disease study equation (eGFR) to estimate GFR was used and examined the prevalence of cardiovascular events in both groups. Unpaired t-test and chi square test were done to find out the level of significance. eGFR was compared between the study groups and significant differences were observed (p value <0.01). Reduced GFR (by estimating MDRD equation) is associated with cardiac event or events and should perform as routine assessment of diabetic patients. Key word: MDRD (Modification of Diet in Renal Disease); eGFR (Estimated Glomerular Filtration Rate); Type 2 Diabetes DOI: 10.3329/akmmcj.v2i1.7464 Anwer Khan Modern Medical College Journal 2011; 2(1): 06-08
Cervical Cancer Vaccination: A New Hope
Authors: Siddiqui Maruf
Published: April 2011

Cervical cancer remains a threat which is second only to breast cancer in overall disease burden for women throughout the world. Organized screening with Pap cytology has made substantial reductions in cervical cancer morbidity and mortality in recent years. Establishment of genital human papillomaviruses (HPVs) as the etiological agent and invention of HPV vaccines now provide a great opportunity which could be useful in saving millions of lives in future. Initial Phase I, II and early phase III trials have shown promising results of this vaccine. This review article therefore is aimed to explore different aspects of this vaccine as well as to develop awareness among health professionals of different disciplines. Key Words: Cervical Cancer; Vaccination; Review DOI: 10.3329/akmmcj.v2i1.7468 Anwer Khan Modern Medical College Journal 2011; 2(1): 26-31
Designs for Living: Female Designers, the Designing Female, Modernism and the Middlebrow
Authors: Briganti Chiara , Mezei Kathy
Published: April 2011

During the interwar period, the artistic endeavour of the female interior decorator was dismissed as old-fashioned, nostalgic, and, tainted by its association with commerce; it was excluded from the rarefied circle of the higher arts of painting and sculpture and architecture; in the novels and plays of middlebrow authors of the same period, on the other hand, the female interior decorator, mocked for her edgy modernity, became a disturbing icon of urban modernity and a controversial advocate for new designs in living. This essay proposes to demonstrate how the representation in fiction and drama of the interwar period of the female interior decorator, a magnet for anxieties about changing gender roles, class distinctions, sexuality and sexual ambiguity and the ‘sanctity’ of the home, complicates the complexity and mutability of the middlebrow and its fraught relationship with modernism.
Droplets Formation and Merging in Two-Phase Flow Microfluidics
Authors: Gu Hao , Duits Michel H. G. , Mugele Frieder
Published: April 2011

Two-phase flow microfluidics is emerging as a popular technology for a wide range of applications involving high throughput such as encapsulation, chemical synthesis and biochemical assays. Within this platform, the formation and merging of droplets inside an immiscible carrier fluid are two key procedures: (i) the emulsification step should lead to a very well controlled drop size (distribution); and (ii) the use of droplet as micro-reactors requires a reliable merging. A novel trend within this field is the use of additional active means of control besides the commonly used hydrodynamic manipulation. Electric fields are especially suitable for this, due to quantitative control over the amplitude and time dependence of the signals, and the flexibility in designing micro-electrode geometries. With this, the formation and merging of droplets can be achieved on-demand and with high precision. In this review on two-phase flow microfluidics, particular emphasis is given on these aspects. Also recent innovations in microfabrication technologies used for this purpose will be discussed.
Bed Bugs: The Australian Response
Authors: Doggett Stephen L. , Orton Christopher J. , Lilly David G. , Russell Richard C.
Published: April 2011

Australia has experienced a sudden and unexpected resurgence in bed bug infestations from both Cimex lectularius L. and Cimex hemipterus F. A survey in 2006 revealed that infestations had increased across the nation by an average of 4,500% since the start of the decade. In response, a multi-disciplinary approach to combat the rise of this public health pest was implemented and involved the coordinated efforts of several organizations. The key components of the strategy included the introduction of a pest management standard ‘A Code of Practice for the Control of Bed Bug Infestations in Australia’ that defines and promotes ‘best practice’ in bed bug eradication, the development of a policy and procedural guide for accommodation providers, education of stakeholders in best management practices, and research. These strategies continue to evolve with developments that lead to improvements in ‘best practice’ while bed bugs remain problematic in Australia.
Kazinol Q from Broussonetia kazinoki Enhances Cell Death Induced by Cu(ll) through Increased Reactive Oxygen Species
Authors: Wei Bai-Luh , Chen Ying-Chieh , Hsu Hsue-Yin
Published: April 2011

The ability of the flavan kazinol Q (KQ) to induce DNA breakage in the presence of Cu(II) was examined by agarose gel electrophoresis using supercoiled plasmid DNA. In KQ-mediated DNA breakage reaction, the involvement of reactive oxygen species (ROS), H2O2 and O2 - was established by the inhibition of DNA breakage by catalase and revealed DNA breakage by superoxide dismutase (SOD). The cell viability of gastric carcinoma SCM-1 cells treated with various concentrations of KQ was significantly decreased by cotreatment with Cu(II). Treatment of SCM-1 cells with 300 μM Cu(II) enhanced the necrosis induced by 100 μM KQ. Treatment of SCM-1 cells with 100 mM KQ in the presence of 300 mM Cu(II) increased the generation of H2O2. Taken together, the above finding suggested that KQ cotreatment with Cu(II) produced increased amounts of H2O2, thus enhancing subsequent cell death due to necrosis.
Structure Identification of Euphorbia Factor L3 and Its Induction of Apoptosis through the Mitochondrial Pathway
Authors: Zhang Jian-Ye , Liang Yong-Ju , Chen Hu-Biao , Zheng Li-Sheng , Mi Yan-Jun , Wang Fang , Zhao Xiao-Qin , Wang Xiao-Kun , Zhang Hui , Fu Li-Wu
Published: April 2011

In this article, we have focused on the structure identification of Euphorbia factor L3 belonging to the lathyrane diterpenoids isolated from Caper Euphorbia Seed. Its anticancer activity in vitro against lung cancer A549 cells was also investigated and the IC50 values were 34.04 ± 3.99 μM. Furthermore, Euphorbia factor L3 could induce apoptosis in A549 cells via the mitochondrial pathway including loss of mitochondrial potential and release of cytochrome c.
A precise age for the Utopia Granite, southwestern New Brunswick, Canada
Authors: Barr Sandra M. , Mortensen James K. , Bevier M. L.
Published: April 2011

The Utopia Granite is part of the Saint George Plutonic Suite, a gabbroic to granitic assemblage of plutons of Late Silurian – Late Devonian age in southwestern New Brunswick. New U-Pb (ID-TIMS) analyses of five fractions of strongly air-abraded zircon grains define a discordant array which suggests that all five fractions have suffered at least some minor degree of post-crystallization Pb-loss and yielded an imprecise upper intercept age of 426.3 ± 5.9 Ma. Fifteen zircon grains analyzed by LA-ICP-MS yielded overlapping concordant analyses, from which a weighted average of the 206Pb/238U ages, excluding one younger age, is 428.3 ± 1.0 Ma (MSWD = 0.66, probability of fit = 0.81), which we interpret as the best estimate for the crystallization age of the Utopia Granite. This age suggests that the Utopia Granite may be the oldest component of the Saint George batholith, and 5–8 million years older than plutons of the contiguous coastal Maine magmatic province to the southwest.

RÉSUMÉ

Le granite Utopia fait partie de la suite plutonique de Saint-George, un assemblage gabbroïque à granitique de plutons du Silurien tardif et de la fin du Dévonien, dans le sud-ouest du Nouveau-Brunswick. De nouvelles analyses U-Pb (ID-TIMS) de cinq fractions de grains de zircon fortement altérés par l’air indiqueraient un assemblage discordant qui porte à croire que les cinq fractions ont subi au moins en partie une perte de plomb après la cristallisation. Les analyses ont permis d’établir de manière imprécise un âge géologique de 426,3 ± 5.9 Ma. Quinze grains de zircon analysés à l’aide des méthode LA-ICP-MS ont produit des résultats concordants qui se recoupaient, dont on a tiré une moyenne pondérée des âges 206Pb/238U de 428,3 ± 1,0 Ma, exception faite d’un âge plus jeune (déviation pondérée de la régression par moindres carrés = 0,66, probabilité de congruence = 0,81). Nous croyons qu’il s’agit là de la meilleure estimation qui soit de la période de cristallisation du granite Utopia. Ces analyses de datation suggèrent que le granite Utopia pourrait être la partie la plus ancienne du batholithe Saint-George, et de 5 à 8 millions d’années plus ancienne que les plutons de la province magmatique de la zone côtière contigüe du Maine, au sud-ouest.[Traduit par la redaction]
An Early Triassic 40Ar/39Ar age for a camptonite dyke in Cambridge, Massachusetts
Authors: Ross Martin E.
Published: April 2011

A 2.4 m-thick megacryst- and xenolith-rich camptonite dyke briefly exposed during excavation of a subway station at Porter Square in Cambridge, Massachusetts, was sampled for petrological study and radiometric dating to constrain its age. The sample yielded a well-defined 40Ar/39Ar age of 246 ± 4 Ma using separates prepared from a ferro-kaersutite mega-phenocryst. This age is the oldest yet reported for a Coastal New England province lamprophyric dyke. The dyke likely reflects regional extension in Avalonia during the initial rifting stage of Pangea to form the North Atlantic Ocean basin. This new age further confirms that mantle upwelling began early in the Late Permian to Triassic as a precursor to the breakup of Pangea some 40 million years later.

RÉSUMÉ

Au cours de travaux d’excavation d’une station de métro à Porter Square, à Cambridge, au Massachusetts, un dyke de campronite d’une épaisseur de 2,4 m composé de mégacristaux et riche en xénolite a été exposé brièvement. On y a prélevé un échantillon aux fins d’une étude pétrologique et d’une datation par radiométrie. Par la méthode 40Ar/39Ar, il a été possible de déterminer avec relativement de précision un âge de 246 ± 4 Ma, grâce à des fractions obtenues par préparation d’un mégaphénocristal de ferro-kaersutite. Il s’agit de la plus ancienne datation établie pour un dyke lamprophyrique de la province géologique du littoral de la Nouvelle-Angleterre. Ce dyke rendrait vraisemblablement compte de l’extension régionale de l’Avalonien au cours du stade initial de distension de la masse continentale de Pangée, qui allait entraîner la création du bassin océanique de l’Atlantique Nord. Cette nouvelle datation vient confirmer une fois de plus que la remontée du manteau terrestre a débuté très tôt entre la fin du Permien et le Trias, cet événement géomorphologique annonçant le fractionnement ultérieur du continent de Pangée quelque 40 millions d’années plus tard.[Traduit par la redaction]
Geochemistry of Carboniferous peralkaline felsic volcanic rocks, central New Brunswick, Canada: examination of uranium potential
Authors: Gray Taryn R. , Dostal Jaroslav , McLeod Malcolm , Keppie Duncan , Zhang Yuanyuan
Published: April 2011

Felsic volcanic rocks from the ca. 335 Ma Cumberland Hill Formation of southern New Brunswick consist of peralkaline rhyolite and trachyte. These rocks are interpreted to have undergone extensive fractional crystallization from an alkali basaltic magma, although their different geochemical signatures indicate that the rhyolite was not derived from the trachyte via continuous fractional crystallization. The rhyolite is highly enriched in incompatible trace elements including uranium (up to ca. 20 ppm). Cumberland Hill peralkaline rhyolite suggests that a potentially economic source of uranium exists in the basin, based on the elevated uranium concentrations and high potential for remobilization into surrounding sedimentary units.

RÉSUMÉ

Les roches volcaniques felsiques de la Formation de Cumberland Hill, au sud du Nouveau-Brunswick, dont l’origine remonte à quelque 335 Ma se composent de rhyolite et de trachyte hyperalcalines. On estime que ces roches ont subi une cristallisation fractionnée intense à partir d’un magma de basalte alcalin, même si leurs diverses signatures géochimiques indiquent que la rhyolite n’est pas issue de la trachyte par un processus permanent de cristallisation fractionnée. La rhyolite est fortement enrichie d’éléments traces incompatibles, au nombre duquel se trouve de l’uranium (concentration qui peut atteindre environ 20 ppm). Si l’on se fie aux fortes concentrations d’uranium et à la grande possibilité de remobilisation dans les unités sédimentaires environnantes, la présence de la rhyolite hyperalcaline dans la Formation de Cumberland Hill porte à croire que le bassin pourrait contenir une source d’uranium vraisemblablement rentable.[Traduit par la redaction]
A Ramsey Theorem with an Application to Sequences in Banach Spaces
Authors: Service Robert
Published: April 2011

The notion of a maximally conditional sequence is introduced for sequences in a Banach space. It is then proved using Ramsey theory that every basic sequence in a Banach space has a subsequence which is either an unconditional basic sequence or a maximally conditional sequence. An apparently novel, purely combinatorial lemma in the spirit of Galvin's theorem is used in the proof. An alternative proof of the dichotomy result for sequences in Banach spaces is also sketched, using the Galvin–Prikry theorem.
The response of precipitation to aerosol through riming and melting in deep convective clouds
Authors: Cui Z. , Davies S. , Carslaw K. S. , Blyth A. M.
Published: April 2011

Abstract. We have used a 2-D axisymmetric, non-hydrostatic, bin-resolved cloud model to examine the impact of aerosol changes on the development of mixed-phase convective clouds. We have simulated convective clouds from four different sites (three continental and one tropical marine) with a wide range of realistic aerosol loadings and initial thermodynamic conditions (a total of 93 different clouds). It is found that the accumulated precipitation responds very differently to changing aerosol in the marine and continental environments. For the continental clouds, the scaled total precipitation reaches a maximum for aerosol that produce drop numbers at cloud base between 180–430 cm−3 when other conditions are the same. In contrast, all the tropical marine clouds show an increase in accumulated precipitation and deeper convection with increasing aerosol loading. For continental clouds, drops are rapidly depleted by ice particles shortly after the onset of precipitation. The precipitation is dominantly produced by melting ice particles. The riming rate increases with aerosol when the loading is very low, and decreases when the loading is high. Peak precipitation intensities tend to increase with aerosol up to drop concentrations (at cloud base) of ~500 cm−3 then decrease with further aerosol increases. This behaviour is caused by the initial transition from warm to mixed-phase rain followed by reduced efficiency of mixed-phase rain at very high drop concentrations. The response of tropical marine clouds to increasing aerosol is different to, and larger than, that of continental clouds. In the more humid tropical marine environment with low cloud bases we find that accumulated precipitation increases with increasing aerosol. The increase is driven by the transition from warm to mixed-phase rain. Our study suggests that the response of deep convective clouds to aerosol will be an important contribution to the spatial and temporal variability in cloud microphysics and precipitation.
Aerosol plume transport and transformation in high spectral resolution lidar measurements and WRF-Flexpart simulations during the MILAGRO Field Campaign
Authors: de Foy B. , Burton S. P. , Ferrare R. A. , Hostetler C. A. , Hair J. W. , Wiedinmyer C. , Molina L. T.
Published: April 2011

Abstract. The Mexico City Metropolitan Area (MCMA) experiences high loadings of atmospheric aerosols from anthropogenic sources, biomass burning and wind-blown dust. This paper uses a combination of measurements and numerical simulations to identify different plumes affecting the basin and to characterize transformation inside the plumes. The High Spectral Resolution Lidar on board the NASA LaRC B-200 King Air aircraft measured extinction coefficients and extinction to backscatter ratio at 532 nm, and backscatter coefficients and depolarization ratios at 532 and 1064 nm. These can be used to identify aerosol types. The measurement curtains are compared with particle trajectory simulations using WRF-Flexpart for different source groups. The good correspondence between measurements and simulations suggests that the aerosol transport is sufficiently well characterized by the models to estimate aerosol types and ages. Plumes in the basin undergo complex transport, and are frequently mixed together. Urban aerosols are readily identifiable by their low depolarization ratios and high lidar ratios, and dust by the opposite properties. Fresh biomass burning plumes have very low depolarization ratios which increase rapidly with age. This rapid transformation is consistent with the presence of atmospheric tar balls in the fresh plumes.
Gravity wave variances and propagation derived from AIRS radiances
Authors: Gong J. , Wu D. L. , Eckermann S. D.
Published: April 2011

Abstract. As the first gravity wave (GW) climatology study using nadir-viewing infrared sounders, 50 Atmospheric Infrared Sounder (AIRS) radiance channels are selected to estimate GW variances at pressure levels between 2–100 hPa. The GW variance for each scan in the cross-track direction is derived from radiance perturbations in the scan, independently of adjacent scans along the orbit. Since the scanning swaths are perpendicular to the satellite orbits, which are inclined meridionally at most latitudes, the zonal component of GW propagation can be inferred by differencing the variances derived between the westmost and the eastmost viewing angles. Consistent with previous GW studies using various satellite instruments, monthly mean AIRS variance shows large enhancements over meridionally oriented mountain ranges as well as some islands at winter hemisphere high latitudes. Enhanced wave activities are also found above tropical deep convective regions. GWs prefer to propagate westward above mountain ranges, and eastward above deep convection. AIRS 90 field-of-views (FOVs), ranging from +48° to −48° off nadir, can detect large-amplitude GWs with a phase velocity propagating preferentially at steep angles (e.g., those from orographic and convective sources). The annual cycle dominates the GW variances and the preferred propagation directions for all latitudes. Quasi-biennial oscillation (QBO) signals are also found in the tropical lower stratosphere despite their small amplitudes. From 90 AIRS FOV radiance measurements, we are able to clearly identify measurement noises, high-frequency internal GWs, and low-frequency inertia GWs. Even though the vertical wavelengths of inertia GWs are shorter than the thickness of instrument weighting functions, simulations support the AIRS sensitivity to these waves. The novel discovery of AIRS capability of observing shallow inertia GWs will expand the potential of satellite GW remote sensing and provide further constraints on the GW drag parameterization schemes in the general circulation models (GCMs).
The observation of chemiluminescent NiO* emissions in the laboratory and in the night airglow
Authors: Evans W. F. J. , Gattinger R. L. , Broadfoot A. L. , Llewellyn E. J.
Published: April 2011

Abstract. The recent finding of an orange spectral feature in OSIRIS/Odin spectra of the night airglow near 85 km has raised interest in the origin of the emission. The feature was positively identified as the chemiluminescent FeO* emission where the iron is of meteoric origin. Since the meteorite source of atomic metals in the mesosphere contains both iron and nickel, with Ni being typically 6% of Fe, it is expected that faint emissions involving Ni should also be present in the night airglow. The present study summarizes the laboratory observations of chemiluminescent NiO* emissions and includes a search for the NiO* signature in the night airglow. A faint previously unidentified "continuum" extending longwave of 440 nm has been identified in night airglow spectra obtained with two space-borne limb viewing instruments and through a comparison with laboratory spectra this continuum is identified as arising from the NiO* emission. The FeO* and NiO* emissions both originate from a reaction of the metal atoms with mesospheric ozone and so support the presence of NiO* in the night airglow.
Response of the Black Sea methane budget to massive short-term submarine inputs of methane
Authors: Schmale O. , Haeckel M. , McGinnis D. F.
Published: April 2011

Abstract. A steady state box model was developed to estimate the methane input into the Black Sea water column at various water depths. Our model results reveal a total input of methane of 4.7 Tg yr−1. The model predicts that the input of methane is largest at water depths between 600 and 700 m (7% of the total input), suggesting that the dissociation of methane gas hydrates at water depths equivalent to their upper stability limit may represent an important source of methane into the water column. In addition we discuss the effects of massive short-term methane inputs (e.g. through eruptions of deep-water mud volcanoes or submarine landslides at intermediate water depths) on the water column methane distribution and the resulting methane emission to the atmosphere. Our non-steady state simulations predict that these inputs will be effectively buffered by intense microbial methane consumption and that the upward flux of methane is strongly hampered by the pronounced density stratification of the Black Sea water column. For instance, an assumed input of methane of 179 Tg CH4 d−1 (equivalent to the amount of methane released by 1000 mud volcano eruptions) at a water depth of 700 m will only marginally influence the sea/air methane flux increasing it by only 3%.
Impact of ocean acidification and elevated temperatures on early juveniles of the polar shelled pteropod Limacina helicina: mortality, shell degradation, and shell growth
Authors: Lischka S. , Büdenbender J. , Boxhammer T. , Riebesell U.
Published: April 2011

Abstract. Due to their aragonitic shell, thecosome pteropods may be particularly vulnerable to ocean acidification driven by anthropogenic CO2 emissions. This applies specifically to species inhabiting Arctic surface waters that are projected to become temporarily and locally undersaturated with respect to aragonite as early as 2016. This study investigated the effects of rising partial pressure of CO2 (pCO2) and elevated temperature on pre-winter juveniles of the polar pteropod Limacina helicina. After a 29 day experiment in September/October 2009 at three different temperatures and under pCO2 scenarios projected for this century, mortality, shell degradation, shell diameter and shell increment were investigated. Temperature and pCO2 had a significant effect on mortality, but temperature was the overriding factor. Shell diameter, shell increment and shell degradation were significantly impacted by pCO2 but not by temperature. Mortality was 46% higher at 8 °C than at in situ temperature (3 °C), and 14% higher at 1100 μatm than at 230 μatm. Shell diameter and increment were reduced by 10 and 12% at 1100 μatm and 230 μatm, respectively, and shell degradation was 41% higher at elevated compared to ambient pCO2. We conclude that pre-winter juveniles will be negatively affected by both rising temperature and pCO2 which may result in a possible decline in abundance of the overwintering population, the basis for next year's reproduction.
Climate change impacts on snow water availability in the Euphrates-Tigris basin
Authors: Özdoğan M.
Published: April 2011

Abstract. This study investigates the effects of projected climate change on snow water availability in the Euphrates-Tigris basin using the Variable Infiltration Capacity (VIC) macro scale hydrologic model and a set of regional climate-change outputs from 13 global circulation models (GCMs) forced with two greenhouse gas emission scenarios for two time periods in the 21st century (2050 and 2090). The hydrologic model produces a reasonable simulation of seasonal and spatial variation in snow cover and associated snow water equivalent (SWE) in the mountainous areas of the basin, although its performance is poorer at marginal snow cover sites. While there is great variation across GCM outputs influencing snow water availability, the majority of models and scenarios suggest a significant decline (between 10 and 60 percent) in available snow water, particularly under the aggressive A2 climate change scenario and later in the 21st century. The changes in SWE are more stable when multi-model ensemble GCM outputs are used to minimize inter-model variability, suggesting a consistent and significant decrease in snow-covered areas and associated water availability in the headwaters of the Euphrates Tigris basin. Detailed analysis of future climatic conditions point to the combined effects of reduced precipitation and increased temperatures as primary drivers of reduced snowpack. Results also indicate a more rapid decline in snow cover in the lower elevation zones than the higher areas in a changing climate. The simulated changes in snow water availability have important implications for the future of water resources and associated hydropower generation and land-use management and planning in a region already ripe for interstate water conflict. While the changes in the frequency and intensity of snow-bearing circulation systems or the interannual variability related to climate were not considered, the simulated changes in snow water availability presented here are likely to be indicative of climate change impacts on the water resources of the Euphrates-Tigris basin.
Prediction of future hydrological regimes in poorly gauged high altitude basins: the case study of the upper Indus, Pakistan
Authors: Bocchiola D. , Diolaiuti G. , Soncini A. , Mihalcea C. , D'Agata C. , Mayer C. , Lambrecht A. , Rosso R. , Smiraglia C.
Published: April 2011

Abstract. In the mountain regions of the Hindu Kush, Karakoram and Himalaya (HKH) the "third polar ice cap" of our planet, glaciers play the role of "water towers" by providing significant amount of melt water, especially in the dry season, essential for agriculture, drinking purposes, and hydropower production. Recently, most glaciers in the HKH have been retreating and losing mass, mainly due to significant regional warming, thus calling for assessment of future water resources availability for populations down slope. However, hydrology of these high altitude catchments is poorly studied and little understood. Most such catchments are poorly gauged, thus posing major issues in flow prediction therein, and representing in facts typical grounds of application of PUB concepts, where simple and portable hydrological modeling based upon scarce data amount is necessary for water budget estimation, and prediction under climate change conditions. In this preliminarily study, future (2060) hydrological flows in a particular watershed (Shigar river at Shigar, ca. 7000 km2), nested within the upper Indus basin and fed by seasonal melt from major glaciers, are investigated. The study is carried out under the umbrella of the SHARE-Paprika project, aiming at evaluating the impact of climate change upon hydrology of the upper Indus river. We set up a minimal hydrological model, tuned against a short series of observed ground climatic data from a number of stations in the area, in situ measured ice ablation data, and remotely sensed snow cover data. The future, locally adjusted, precipitation and temperature fields for the reference decade 2050–2059 from CCSM3 model, available within the IPCC's panel, are then fed to the hydrological model. We adopt four different glaciers' cover scenarios, to test sensitivity to decreased glacierized areas. The projected flow duration curves, and some selected flow descriptors are evaluated. The uncertainty of the results is then addressed, and use of the model for nearby catchments discussed. The proposed approach is valuable as a tool to investigate the hydrology of poorly gauged high altitude areas, and to project forward their hydrological behavior pending climate change.
Development of flood probability charts for urban drainage network in coastal areas through a simplified joint assessment approach
Authors: Archetti R. , Bolognesi A. , Casadio A. , Maglionico M.
Published: April 2011

Abstract. The operating conditions of urban drainage networks during storm events certainly depend on the hydraulic conveying capacity of conduits but also on downstream boundary conditions. This is particularly true in costal areas where the level of the receiving water body is directly or indirectly affected by tidal or wave effects. In such cases, not just different rainfall conditions (varying intensity and duration), but also different sea-levels and their effects on the network operation should be considered. This paper aims to study the behaviour of a seaside town storm sewer network, estimating the threshold condition for flooding and proposing a simplified method to assess the urban flooding severity as a function of either climate variables. The case study is a portion of the drainage system of Rimini (Italy), implemented and numerically modelled by means of InfoWorks CS code. The hydraulic simulation of the sewerage system has therefore allowed to identify the percentage of nodes of the drainage system where flooding is expected to occur. Combining these percentages with both climate variables values has lead to the definition charts representing the combined degree of risk "sea-rainfall" for the drainage system under investigation. A final comparison between such charts and the results obtained from a one-year sea-rainfall time series has confirmed the reliability of the analysis.
On the influence of model physics on simulations of Arctic and Antarctic sea ice
Authors: Massonnet F. , Fichefet T. , Goosse H. , Vancoppenolle M. , Mathiot P. , König Beatty C.
Published: April 2011

Abstract. Two hindcast (1983–2007) simulations are performed with the global, ocean-sea ice models NEMO-LIM2 and NEMO-LIM3 driven by atmospheric reanalyses and climatologies. The two simulations differ only in their sea ice component, while all other elements of experimental design (resolution, initial conditions, atmospheric forcing) are kept identical. The main differences in the sea ice models lie in the formulation of the subgrid-scale ice thickness distribution, of the thermodynamic processes, of the sea ice salinity and of the sea ice rheology. To assess the differences in model skill over the period of investigation, we develop a set of metrics for both hemispheres, comparing the main sea ice variables (concentration, thickness and drift) to available observations and focusing on both mean state and seasonal to interannual variability. Based upon these metrics, we discuss the physical processes potentially responsible for the differences in model skill. In particular, we suggest that (i) a detailed representation of the ice thickness distribution increases the seasonal to interannual variability of ice extent, with spectacular improvement for the simulation of the recent observed summer Arctic sea ice retreats, (ii) the elastic-viscous-plastic rheology enhances the response of ice to wind stress, compared to the classical viscous-plastic approach, (iii) the grid formulation and the air-sea ice drag coefficient affect the simulated ice export through Fram Strait and the ice accumulation along the Canadian Archipelago, and (iv) both models show less skill in the Southern Ocean, probably due to the low quality of the reanalyses in this region and to the absence of important small-scale oceanic processes at the models' resolution (~1°).