bluuebunny/crossref_metadata_2025 huggingface dataset:
Retinoic Acid and VEGF Delay Smooth Muscle Relative to Endothelial Differentiation to Coordinate Inner and Outer Coronary Vessel Wall Morphogenesis
Authors: Azambuja Ana P. , Portillo-Sánchez Victor , Rodrigues Mariliza V. , Omae Samantha V. , Schechtman Deborah , Strauss Bryan E. , Costanzi-Strauss Eugenia , Krieger José E. , Perez-Pomares José M. , Xavier-Neto José
Published: June 2010

Rationale
:

Major coronary vessels derive from the proepicardium, the cellular progenitor of the epicardium, coronary endothelium, and coronary smooth muscle cells (CoSMCs). CoSMCs are delayed in their differentiation relative to coronary endothelial cells (CoEs), such that CoSMCs mature only after CoEs have assembled into tubes. The mechanisms underlying this sequential CoE/CoSMC differentiation are unknown. Retinoic acid (RA) is crucial for vascular development and the main RA-synthesizing enzyme is progressively lost from epicardially derived cells as they differentiate into blood vessel types. In parallel, myocardial vascular endothelial growth factor (VEGF) expression also decreases along coronary vessel muscularization.

Objective
:

We hypothesized that RA and VEGF act coordinately as physiological brakes to CoSMC differentiation.

Methods and Results
:

In vitro assays (proepicardial cultures, cocultures, and RALDH2 [retinaldehyde dehydrogenase-2]/VEGF adenoviral overexpression) and in vivo inhibition of RA synthesis show that RA and VEGF act as repressors of CoSMC differentiation, whereas VEGF biases epicardially derived cell differentiation toward the endothelial phenotype.

Conclusion
:

Experiments support a model in which early high levels of RA and VEGF prevent CoSMC differentiation from epicardially derived cells before RA and VEGF levels decline as an extensive endothelial network is established. We suggest this physiological delay guarantees the formation of a complex, hierarchical, tree of coronary vessels.
Smad3 Signaling Critically Regulates Fibroblast Phenotype and Function in Healing Myocardial Infarction
Authors: Dobaczewski Marcin , Bujak Marcin , Li Na , Gonzalez-Quesada Carlos , Mendoza Leonardo H. , Wang Xiao-Fan , Frangogiannis Nikolaos G.
Published: June 2010

Rationale:

Cardiac fibroblasts are key effector cells in the pathogenesis of cardiac fibrosis. Transforming growth factor (TGF)-β/Smad3 signaling is activated in the border zone of healing infarcts and induces fibrotic remodeling of the infarcted ventricle contributing to the development of diastolic dysfunction.

Objective:

The present study explores the mechanisms responsible for the fibrogenic effects of Smad3 by dissecting its role in modulating cardiac fibroblast phenotype and function.

Methods and Results:

Smad3 null mice and corresponding wild-type controls underwent reperfused myocardial infarction protocols. Surprisingly, reduced collagen deposition in Smad3−/− infarcts was associated with increased infiltration with myofibroblasts. In vitro studies demonstrated that TGF-β1 inhibited murine cardiac fibroblast proliferation; these antiproliferative effects were mediated via Smad3. Smad3−/− fibroblasts were functionally defective, exhibiting impaired collagen lattice contraction when compared with wild-type cells. Decreased contractile function was associated with attenuated TGF-β–induced expression of α-smooth muscle actin. In addition, Smad3−/− fibroblasts had decreased migratory activity on stimulation with serum, and exhibited attenuated TGF-β1–induced upregulation of extracellular matrix protein synthesis. Upregulation of connective tissue growth factor, an essential downstream mediator in TGF-β–induced fibrosis, was in part dependent on Smad3. Connective tissue growth factor stimulation enhanced extracellular matrix protein expression by cardiac fibroblasts in a Smad3-independent manner.

Conclusions:

Disruption of Smad3 results in infiltration of the infarct with abundant hypofunctional fibroblasts that exhibit impaired myofibroblast transdifferentiation, reduced migratory potential, and suppressed expression of fibrosis-associated genes.
Ischemic Stroke and Secondary Prevention in Clinical Practice
Authors: Åsberg Signild , Henriksson Karin M. , Farahmand Bahman , Asplund Kjell , Norrving Bo , Appelros Peter , Stegmayr Birgitta , Åsberg Kerstin Hulter , Terént Andreas
Published: June 2010

Background and Purpose—

Secondary prevention is recommended after stroke, but adherence to guidelines is unknown. We studied the prescription of antiplatelet drugs, angiotensin-converting enzyme inhibitors, statins, and anticoagulant drugs and their relation to risk of death.

Methods—

Patients with first-ever ischemic stroke in 2005 were registered in the Swedish Stroke Register. Odds ratios, hazard ratios, and 95% CIs were calculated using logistic and Cox proportional hazard regression models. Adjustments were performed for age, sex, cardiovascular risk factors, other drug therapies, and activities of daily living function.

Results—

In total, 14 529 patients with a mean age of 75.0 (±11.6) years were included. They were followed for 1.4 (±0.5) years: 52% had hypertension, 26% atrial fibrillation, 19% diabetes, and 15% were smokers. The odds ratio for prescription of antiplatelet was 2.20 (95% CI, 1.86 to 2.60) among the oldest patients (≥85 years of age) compared with the youngest (18 to 64 years of age). The corresponding odds ratio was 0.38 (0.32 to 0.45) for prescriptions of angiotensin-converting enzyme inhibitors, 0.09 (0.08 to 0.11) for statins, and 0.07 (0.05 to 0.09) for anticoagulant therapy. Prescription of statin and anticoagulant therapy was associated with reduced risk of death (hazard ratio, 0.78 [0.65 to 0.91] and hazard ratio, 0.58 [0.44 to 0.76], respectively) but not the prescription of antiplatelet drugs or angiotensin-converting enzyme inhibitors.

Conclusions—

The prescription of antiplatelet, angiotensin-converting enzyme inhibitors, statins, and anticoagulant therapy was strongly age related. Statin and anticoagulant therapy was associated with reduced risk of death and seemed to be underused among elderly patients. These findings should encourage physicians to follow today’s guidelines for stroke care.
High VEGFC expression is associated with unique gene expression profiles and predicts adverse prognosis in pediatric and adult acute myeloid leukemia
Authors: de Jonge Hendrik J. M. , Valk Peter J. M. , Veeger Nic J. G. M. , ter Elst Arja , den Boer Monique L. , Cloos Jacqueline , Haas Valérie de , van den Heuvel-Eibrink Marry M. , Kaspers Gertjan J. L. , Zwaan Christian M. , Kamps Willem A. , Löwenberg Bob , de Bont Eveline S. J. M.
Published: June 2010

High VEGFC mRNA expression of acute myeloid leukemia (AML) blasts is related to increased in vitro and in vivo drug resistance. Prognostic significance of VEGFC on long-term outcome and its associated gene expression profiles remain to be defined. We studied effect of VEGFC on treatment outcome and investigated gene expression profiles associated with VEGFC using microarray data of 525 adult and 100 pediatric patients with AML. High VEGFC expression appeared strongly associated with reduced complete remission rate (P = .004), reduced overall and event-free survival (OS and EFS) in adult AML (P = .002 and P < .001, respectively). Multivariable analysis established high VEGFC as prognostic indicator independent of cytogenetic risk, FLT3-ITD, NPM1, CEBPA, age, and white blood cell count (P = .038 for OS; P = .006 for EFS). Also, in pediatric AML high VEGFC was related to reduced OS (P = .041). A unique series of differentially expressed genes was identified that distinguished AML with high VEGFC from AML with low VEGFC, that is, 331 up-regulated genes (representative of proliferation, vascular endothelial growth factor receptor activity, signal transduction) and 44 down-regulated genes (eg, related to apoptosis) consistent with a role in enhanced chemoresistance. In conclusion, high VEGFC predicts adverse long-term prognosis and provides prognostic information in addition to well-known prognostic factors.
Immunophenotypic features of tumor infiltrating lymphocytes from mammary carcinomas in female dogs associated with prognostic factors and survival rates
Authors: Estrela-Lima Alessandra , Araújo Márcio SS , Costa-Neto João M , Teixeira-Carvalho Andréa , Barrouin-Melo Stella M , Cardoso Sergio V , Martins-Filho Olindo A , Serakides Rogéria , Cassali Geovanni D
Published: June 2010

Background

The immune system plays an important role in the multifactorial biologic system during the development of neoplasias. However, the involvement of the inflammatory response in the promotion/control of malignant cells is still controversial, and the cell subsets and the mechanisms involved are poorly investigated. The goal of this study was to characterize the clinical-pathological status and the immunophenotyping profile of tumor infiltrating lymphocytes and their association with the animal survival rates in canine mammary carcinomas.

Methods

Fifty-one animals with mammary carcinomas, classified as carcinomas in mixed tumors-MC-BMT = 31 and carcinomas-MC = 20 were submitted to systematic clinical-pathological analysis (tumor size; presence of lymph node and pulmonary metastasis; clinical stage; histological grade; inflammatory distribution and intensity as well as the lymphocytic infiltrate intensity) and survival rates. Twenty-four animals (MC-BMT = 16 and MC = 8) were elected to the immunophenotypic study performed by flow cytometry.

Results

Data analysis demonstrated that clinical stage II-IV and histological grade was I more frequent in MC-BMT as compared to MC. Univariate analysis demonstrated that the intensity of inflammation (moderate/intense) and the proportion of CD4+(≥ 66.7%) or CD8+T-cells (<33.3%) were not associated with worse survival rate. Multivariate analysis demonstrated that only lymphocytic infiltrate intensity ≥ 600 (P= 0.02) remained as independent prognostic factor. Despite the clinical manifestation, the lymphocytes represented the predominant cell type in the tumor infiltrate. The percentage of T-cells was higher in animals with MC-BMT without metastasis, while the percentage of B-lymphocytes was greater in animals with metastasized MC-BMT (P< 0.05). The relative percentage of CD4+T-cells was significantly greater in metastasized tumors (both MC-BMT and MC), (P< 0.05) while the proportion of CD8+T-cells was higher in MC-BMT without metastasis. Consequently, the CD4+/CD8+ratio was significantly increased in both groups with metastasis. Regardless of the tumor type, the animals with high proportions of CD4+and low CD8+T-cells had decreased survival rates.

Conclusion

The intensity of lymphocytic infiltrate and probably the relative abundance of the CD4+and CD8+T-lymphocytes may represent important survival prognostic biomarkers for canine mammary carcinomas.
Efficacy of different types of aerobic exercise in fibromyalgia syndrome: a systematic review and meta-analysis of randomised controlled trials
Authors: Häuser Winfried , Klose Petra , Langhorst Jost , Moradi Babak , Steinbach Mario , Schiltenwolf Marcus , Busch Angela
Published: June 2010

Introduction

The efficacy and the optimal type and volume of aerobic exercise (AE) in fibromyalgia syndrome (FMS) are not established. We therefore assessed the efficacy of different types and volumes of AE in FMS.

Methods

The Cochrane Library, EMBASE, MEDLINE, PsychInfo and SPORTDISCUS (through April 2009) and the reference sections of original studies and systematic reviews on AE in FMS were systematically reviewed. Randomised controlled trials (RCTs) of AE compared with controls (treatment as usual, attention placebo, active therapy) and head-to-head comparisons of different types of AE were included. Two authors independently extracted articles using predefined data fields, including study quality indicators.

Results

Twenty-eight RCTs comparing AE with controls and seven RCTs comparing different types of AE with a total of 2,494 patients were reviewed. Effects were summarised using standardised mean differences (95% confidence intervals) by random effect models. AE reduced pain (-0.31 (-0.46, -0.17); P < 0.001), fatigue (-0.22 (-0.38, -0.05); P = 0.009), depressed mood (-0.32 (-0.53, -0.12); P = 0.002) and limitations of health-related quality of life (HRQOL) (-0.40 (-0.60, -0.20); P < 0.001), and improved physical fitness (0.65 (0.38, 0.95); P < 0.001), post treatment. Pain was significantly reduced post treatment by land-based and water-based AE, exercises with slight to moderate intensity and frequency of two or three times per week. Positive effects on depressed mood, HRQOL and physical fitness could be maintained at follow-up. Continuing exercise was associated with positive outcomes at follow-up. Risks of bias analyses did not change the robustness of the results. Few studies reported a detailed exercise protocol, thus limiting subgroup analyses of different types of exercise.

Conclusions

An aerobic exercise programme for FMS patients should consist of land-based or water-based exercises with slight to moderate intensity two or three times per week for at least 4 weeks. The patient should be motivated to continue exercise after participating in an exercise programme.
Tumor necrosis factor and norepinephrine lower the levels of human neutrophil peptides 1-3 secretion by mixed synovial tissue cultures in osteoarthritis and rheumatoid arthritis
Authors: Riepl Birgit , Grässel Susanne , Wiest Reiner , Fleck Martin , Straub Rainer H
Published: June 2010

Introduction

Neutrophils and monocytes play an important role in overt inflammation in chronic inflammatory joint diseases such as rheumatoid arthritis (RA). The sympathetic nervous system (SNS) inhibits many neutrophil/monocyte functions and macrophage tumor necrosis factor (TNF), but because of the loss of sympathetic nerve fibers in inflamed tissue, sympathetic control is attenuated. In this study, we focused on noradrenergic and TNF regulation of human neutrophil peptides 1-3 (HNP1-3), which are proinflammatory bactericidal α-defensins.

Methods

Synovial tissue and cells were obtained from patients with RA and osteoarthritis (OA). By using immunohistochemistry and immunofluorescence, HNP1-3 were tracked in the tissue. With synovial cell-culture experiments and ELISA, effects of norepinephrine, TNF, and cortisol on HNP1-3 were detected.

Results

HNP1-3 were abundantly expressed in the synovial lining and adjacent sublining area but not in deeper layers of synovial tissue. The human β-defensin-2, used as control, was hardly detectable in the tissue and in supernatants. HNP1-3 double-stained with neutrophils but not with macrophages, fibroblasts, T/B lymphocytes, and mast cells. Norepinephrine dose-dependently decreased HNP1-3 levels from RA and OA cells. TNF also inhibited HNP1-3 levels from OA but not from RA cells. Cortisol inhibited HNP1-3 levels only in OA patients. A combination of norepinephrine and cortisol did not show additive or synergistic effects.

Conclusions

This study demonstrated an inhibitory effect of norepinephrine on HNP1-3 of mixed synovial cells. In light of these findings, the loss of sympathetic nerve fibers with low resting norepinephrine levels might also augment the inflammatory process through HNP1-3.
Effect of signal amplitude on magnetic depth estimations
Authors: Lee Madeline , Morris Bill , Ugalde Hernan
Published: June 2010

The magnetic signal generated over any source can be analyzed in terms of the two basic components of any wave: frequency (λ) and amplitude (A). With respect to magnetics, the frequency will be a function of the magnetic source body depth and geometry, while the amplitude is a function of magnetization intensity (magnetic susceptibility and natural remanent magnetization, NRM, if present). Many processing and interpretation methods developed over the last 50 years take advantage of the intrinsic relationship between frequency and depth to generate a variety of depth-estimation routines. Furthermore, many methods are independent of magnetic susceptibility (and therefore amplitude) contrasts since the methods incorporate some sort of mathematical expression that nulls the effect of varying susceptibilities.
Subsalt 3D VSP imaging at Deimos Field in the deepwater Gulf of Mexico
Authors: Burch Tom , Hornby Brian , Sugianto Hans , Nolte Bertram
Published: June 2010

At Deimos Field in the deepwater Gulf of Mexico, surface seismic imaging cannot fully image sedimentary structure near the steeply dipping base of salt. 3D vertical seismic profile (VSP) imaging was introduced to the deepwater GOM to improve seismic imaging of complex structural and stratigraphic features (Ray et al., 2003; Hornby et al., 2006) and recently has been used for imaging “blind spots” in surface seismic coverage (Hornby et al., 2005; Hornby et al., 2007). With this method, 3D surveys are conducted using a surface source vessel and downhole geophones. Here we investigate the use of 3D VSP imaging to complement the surface results with additional coverage beyond that of the surface seismic adjacent to the complex salt body.
Virtual source method applied to crosswell and horizontal well geometries
Authors: Mehta Kurang , Kiyashchenko Denis , Jorgensen Patsy , Lopez Jorge , Ferrandis Javier , Costello Michael
Published: June 2010

The virtual source method is a useful tool for redatuming a seismic survey below complicated overburden by creating virtual sources at downhole receiver locations, hence generating data independent of the overburden and the time-lapse changes therein. In this article we first apply this technique to crosswell geometries, whereby a virtual crosswell survey is simulated by shooting a line of surface shots passing through two boreholes instrumented with downhole sensors. Using this acquisition geometry, receivers in one of the two wells are turned into virtual sources by correlating the wavefield recorded by those receivers with the recording at receivers in the other well, and summing the correlated data over the surface shots.
Mortality in Patients with Pituitary Disease
Authors: Sherlock Mark , Ayuk John , Tomlinson Jeremy W. , Toogood Andrew A. , Aragon-Alonso Aurora , Sheppard Michael C. , Bates Andrew S. , Stewart Paul M.
Published: June 2010

Pituitary disease is associated with increased mortality predominantly due to vascular disease. Control of cortisol secretion and GH hypersecretion (and cardiovascular risk factor reduction) is key in the reduction of mortality in patients with Cushing’s disease and acromegaly, retrospectively. For patients with acromegaly, the role of IGF-I is less clear-cut. Confounding pituitary hormone deficiencies such as gonadotropins and particularly ACTH deficiency (with higher doses of hydrocortisone replacement) may have a detrimental effect on outcome in patients with pituitary disease. Pituitary radiotherapy is a further factor that has been associated with increased mortality (particularly cerebrovascular). Although standardized mortality ratios in pituitary disease are falling due to improved treatment, mortality for many conditions are still elevated above that of the general population, and therefore further measures are needed. Craniopharyngioma patients have a particularly increased risk of mortality as a result of the tumor itself and treatment to control tumor growth; this is a key area for future research in order to optimize the outcome for these patients.
Multidimensional Mechanism Design: Finite-Dimensional Approximations and Efficient Computation
Authors: Belloni Alexandre , Lopomo Giuseppe , Wang Shouqiang
Published: June 2010

Multidimensional mechanism design problems have proven difficult to solve by extending techniques from the one-dimensional case. This paper considers mechanism design problems with multidimensional types when the seller's cost function is not separable across buyers. By adapting results obtained by Border [Border, K. 1991. Implementation of reduced form auctions: A geometric approach. Econometrica 59 1175–1187], we transform the seller's problem into a representation that only involves “interim” variables and eliminates the dimensionality dependence on the number of buyers. We show that the associated infinite-dimensional optimization problem posed by the theoretical model can be approximated arbitrarily well by a sequence of finite-dimensional linear programming problems.

We provide an efficient—i.e., terminating in polynomial time in the problem size—method to compute the separation oracle associated with the Border constraints and incentive compatibility constraints. This implies that our finite-dimensional approximation is solvable in polynomial time.

Finally, we illustrate how the numerical solutions of the finite-dimensional approximations can provide insights into the nature of optimal solutions to the infinite-dimensional problem in particular cases.
Use of functionalized β-lactams as building blocks in heterocyclic chemistry
Authors: D’hooghe Matthias , Dekeukeleire Stijn , Leemans Erika , De Kimpe Norbert
Published: June 2010

β-Lactams represent flexible building blocks suitable for the preparation of a large variety of nitrogen-containing target compounds. In the present study, the formerly neglected synthetic potential of 4-haloalkyl-β-lactams has been elaborated in detail with a focus on the preparation of different mono- and bicyclic heterocycles. A first approach involved ring transformations of these halogenated building blocks toward stereodefined aziridines, azetidines, pyrrolidines, and piperidines via intermediate aziridinium or azetidinium ions. In a second part, novel and stereoselective entries into 1,4- and 3,4-fused bicyclic β-lactams were developed through either a radical or an ionic cyclization protocol. Furthermore, the ring enlargement of halogenated β-lactams into functionalized mono- and bicyclic pyrrolidin-2-ones was established as the aza-analog of the cyclobutylmethylcarbenium ion to cyclopentylcarbenium ion rearrangement. Finally, chiral versions toward azetidin-2-ones and ring transformation products were elaborated, involving the synthesis of 3(S)-alkoxy-4(S)-[1(S)-chloroethyl]azetidin-2-ones and the preparation of bicyclic β-lactams annelated to piperazines, morpholines, and diazepanes.
Use of the red blood cell as a simple drug target and diagnostic by manipulating and monitoring its ability to release adenosine triphosphate (ATP)
Authors: Tolan Nicole V. , Meyer Jennifer A. , Ku Chia-Jui , Karunarathne Welivitiya , Spence Dana M.
Published: June 2010

Without question, one of the main tasks of the red blood cell (RBC) is to deliver oxygen to various tissues and organs in vivo. However, due to the lack of a nucleus and mito-chondria, the RBC is typically not thought to be a determinant in many diseases or abnormal physiological conditions. Recent efforts by many labs world-wide are resulting in a body of evidence, suggesting that the RBC may serve many other roles in vivo besides that of an oxygen carrier. If so, the RBC may eventually emerge as one of the simplest drug targets and diagnostic tools available. Here, molecular evidence is provided, suggesting that the RBC, via its ability (or inability) to maintain proper levels of adenosine triphosphate (ATP) release in the circulation, may be a major factor in vascular regulation. Moreover, due to the RBC’s response to slight modifications in its normal environment, the use of the RBC as an important diagnostic for early prediction of disease onset is discussed.
Development of a Sliding-Rolling Contact Fatigue Tester
Authors: Dvorak Gregory , Zahui Marcellin , Mitton Bryce
Published: June 2010

Contact fatigue failure is a common problem experienced in many applications such as bearings, gears, and railway tracks. In recent years, research companies have developed finishing processes that aim to improve components’ contact fatigue life. Preliminary rolling contact fatigue tests have shown that superfinishing processes could potentially improve a component’s contact fatigue life by 300 %. However, before these technologies can move from the laboratories to industrial platforms, more tests are needed to verify the claim. The objective of the work herein is to discuss the completion and verification of a sliding-rolling contact fatigue (S-RCF) test rig. This project is funded by the U.S. Army to assess the real benefit of superfinishing on the contact fatigue life of gears used in helicopter transmission boxes. The proposed tester design uses three rollers around a specimen, a hydraulic loading mechanism, and two servo motors. This configuration of the S-RCF tester allows for shorter testing time, more flexible testing parameters such as any combination of slide-roll ratio between the surfaces, any operating speed, and dry or lubricated testing conditions. Failure is detected with a state-of-the-art eddy current crack detection system, which can also be used to monitor and investigate crack growth for different materials, levels of superfinish, and operating conditions. Preliminary tests on a common gear material (AISI 8620 steel) were performed to assess the mechanical limits as well as the control software performance. This paper presents the detailed development and validation of the tester. It discusses issues involved with servo controllers, electronic gear ratio, and their ability to provide precise speed and slip ratios.
Synthetic Jet Fuel Blend Analysis Using Mid-Infrared Spectroscopy
Authors: Wilks Dylan
Published: June 2010

With recent volatile oil prices and the desire to reduce dependence on foreign oil, the airline industry and military are looking at ways to supplement the fuel supply. Synthetic jet fuel has recently come to the forefront as a possible solution since it has chemical properties and energy density similar to that of petroleum based jet fuel. In order to successfully implement synthetic jet fuels into a fuel supply, it is essential to know the blend ratio of synthetic to standard jet fuel. A portable mid-infrared analyzer was evaluated as a possible tool to analyze the blend ratio. Preliminary results showed that portable mid-infrared analyzers have an accuracy better than 1 % by volume. Both commercial (Jet A) and military spec (JP-8) fuels were blended with different levels of synthetic jet fuel, and calibrations were generated on a portable mid-infrared spectrometer. The mid-infrared spectrometer performed within an acceptable accuracy with both fuels. In addition, it was possible to calibrate using Jet A fuel and predict the synthetic blend ratio on JP-8 fuel, so the calibration was robust enough to compensate for different fuel types. Further studies are underway in order to determine the effects of fuel additives and different synthetic fuel types on infrared analysis.
Clathrin is essential for meiotic spindle function in oocytes
Authors: Hölzenspies Jurriaan J , Roelen Bernard A J , Colenbrander Ben , Romijn Roland A P , Hemrika Wieger , Stoorvogel Willem , van Haeften Theo
Published: June 2010

In the mammalian ovary, oocytes are arrested at prophase of meiosis I until a hormonal stimulus triggers resumption of meiosis. During the subsequent meiotic maturation process, which includes completion of the first meiotic division and formation of the second metaphase spindle, oocytes acquire competence for fertilization. Recently, it was shown that clathrin, a cytosolic protein complex originally defined for its role in intracellular membrane traffic, is also involved in the stabilization of kinetochore fibers in mitotic spindles of dividing somatic cells. However, whether clathrin has a similar function in meiotic spindles in oocytes has not been investigated previously. Our results show that endogenous clathrin associates with the meiotic spindles in oocytes. To study the function of clathrin during meiotic maturation, we microinjected green fluorescent protein-tagged C-terminal and N-terminal dominant-negative clathrin protein constructs into isolated porcine oocytes prior toin vitromaturation. Both protein constructs associated with meiotic spindles similar to endogenous clathrin, but induced misalignment and clumping of chromosomes, occurrence of cytoplasmic chromatin and failure of polar body extrusion. These data demonstrate that clathrin plays a crucial role in meiotic spindle function in maturing oocytes, possibly through spindle stabilization.
Predator proximity as a stressor in breeding flycatchers: mass loss, stress protein induction, and elevated provisioning
Authors: Thomson Robert L. , Tomás Gustavo , Forsman Jukka T. , Broggi Juli , Mönkkönen Mikko
Published: June 2010

We investigated the physiological and behavioral consequences for prey breeding at different distances from a nesting predator. In a natural setting, Pied Flycatchers (Ficedula hypoleuca) made territory location decisions relative to established Sparrowhawk (Accipiter nisus) nests. From female flycatchers attending nests at different distances from Sparrowhawk nests, we measured body mass, blood stress protein (HSP60 and HSP70), and plasma immunoglobulin levels at the beginning (initial) and end (final) of the flycatcher breeding cycle, and provisioning rates during the nestling phase. We found that individuals breeding in closer proximity to Sparrowhawk nests, under higher perceived predation risk, showed significantly lower body mass, higher stress protein and immunoglobulin levels, and higher nestling provisioning rates compared to those individuals breeding farther away. Across the range of distances investigated (30–610 m), final stress protein levels decreased linearly with distance, whereas the final measures of the other variables showed unimodal trends, increasing or decreasing until an intermediate distance (~350 m) and reversing the direction of the trend. Within 300 m, however, all measures showed significant linear associations with distance from the Sparrowhawk nest. Body mass and stress protein associations with distance from Sparrowhawk nests were only present during late breeding, and not in early incubation. Spatial proximity to Sparrowhawk nests consistently explained significant variation in both physiological and behavioral measures, despite the multitude of potential sources of variation for these measures in a natural setting. This suggests that predictable spatial patterns in these measures in avian communities are determined by the sites of breeding predators. Habitat selection decisions of migrant prey that vary only slightly spatially have consequences even at the cellular level, which plausibly have impacts on individual survival. In addition, this study suggests that predation risk is an important factor affecting physiological condition of prey, including stress protein induction in terrestrial vertebrates.
Latitudinal variation in seasonal activity and mortality in ratsnakes (Elaphe obsoleta)
Authors: Sperry Jinelle H. , Blouin-Demers Gabriel , Carfagno Gerardo L. F. , Weatherhead Patrick J.
Published: June 2010

The ecology of ectotherms should be particularly affected by latitude because so much of their biology is temperature dependent. Current latitudinal patterns should also be informative about how ectotherms will have to modify their behavior in response to climate change. We used data from a total of 175 adult black ratsnakes (Elaphe obsoleta) radio‐tracked in Ontario, Illinois, and Texas, a latitudinal distance of >1500 km, to test predictions about how seasonal patterns of activity and mortality should vary with latitude. Despite pronounced differences in temperatures among study locations, and despite ratsnakes in Texas not hibernating and switching from diurnal to nocturnal activity in the summer, seasonal patterns of snake activity were remarkably similar during the months that snakes in all populations were active. Rather than being a function of temperature, activity may be driven by the timing of reproduction, which appears similar among populations. Contrary to the prediction that mortality should be highest in the most active population, overall mortality did not follow a clinal pattern. Winter mortality did increase with latitude, however, consistent with temperature limiting the northern distribution of ratsnakes. This result was opposite that found in the only previous study of latitudinal variation in winter mortality in reptiles, which may be a consequence of whether or not the animals exhibit true hibernation. Collectively, these results suggest that, at least in the northern part of their range, ratsnakes should be able to adjust easily to, and may benefit from, a warmer climate, although climate‐based changes to the snakes' prey or habitat, for example, could alter that prediction.
On goodness‐of‐fit measure for dendrogram‐based analyses
Authors: Mérigot Bastien , Durbec Jean-Pierre , Gaertner Jean-Claude
Published: June 2010

Clustering methods are widely used tools in many aspects of science, such as ecology, medicine, or even market research, that commonly deal with dendrogram‐based analyses. In such analyses, for a given initial dissimilarity matrix, the resulting dendrogram may strongly vary according to the selected clustering methods. However, numerous dendrogram‐based analyses require adequate measurement for assessing of which of the clustering methods preserves most faithfully the initial dissimilarity matrix. While cophenetic correlation coefficient‐based measures have been widely used for this purpose, we emphasize here that it is not always a suitable approach. We thus propose a measure based on a matrix norm, the 2‐norm, to adequately check which of the resulting ultrametric distance matrices related to the dendrograms is the closest to the initial dissimilarity matrix. In addition, we also propose an objective way to define a benchmark value (threshold value) in order to assess whether the degree of conformity between the ultrametric distance matrix selected and the initial dissimilarity matrix is satisfactory. Our proposal may notably be incorporated within a recently proposed approach that involves the use of clustering methods in environmental science and beyond. In ecology, various functional diversity indices based on clustering species from their functional dissimilarities may benefit from this overall approach.
A 12‐year study on the scaling of vascular plant composition in an Oklahoma tallgrass prairie
Authors: McGlinn Daniel J. , Earls Peter G. , Palmer Michael W.
Published: June 2010

We present data that were collected as part of a monitoring project on vascular plant composition at the Tallgrass Prairie Preserve in Osage County, Oklahoma, USA. The purpose of these data are to promote the study of multi‐scale patterns of species composition for both theoretical and applied questions. Furthermore, these data will provide a reference point for tallgrass prairie restoration projects in the Flint Hills. Over the course of the 12‐year period, we sampled 20 permanent plots annually. The permanent plots were selected semi‐randomly from a UTM grid using the criteria that they contain less than 20% of woody cover, standing water, or exposed rock. Plant species presence was recorded at five spatial scales: 0.01, 0.1, 1.0, 10, and 100 m2 in each of the four corners of a 100‐m2 square quadrat. Plant species were assigned to a percent cover class at the 100‐m2 grain. In addition to information on plant composition, we provide data on topography, soil variables, monthly total rainfall, monthly average temperature, and management records related to fire and grazing history. We hope this data set will stimulate further research into the scaling of biodiversity and insight into the functioning and conservation of tallgrass prairie plant communities.
Pesticides, aquatic food webs, and the conservation of Pacific salmon
Authors: Macneale Kate H , Kiffney Peter M , Scholz Nathaniel L
Published: June 2010

Pesticides pose complex threats to the biological integrity of aquatic ecosystems. In the western US, pesticides have contaminated many surface waters that provide habitat for endangered salmon. These iconic species depend on the productivity of rivers, lakes, and estuaries to provide food for juvenile growth, a key determinant of subsequent marine survival. Despite extensive societal investments in salmon habitat restoration in recent years, the role of pesticides as a limiting factor for salmon recovery has received little attention. Pesticides can be toxic to primary producers and macroinvertebrates, thereby limiting salmon population recovery through adverse, bottom‐up impacts on aquatic food webs. The integration of toxicology, environmental chemistry, population biology, community ecology, landscape ecology, conservation biology, and environmental policy is needed to better understand these indirect effects of pesticides on endangered species. We highlight key information gaps and discuss how future research on pesticides and food webs can most effectively guide the long‐term conservation of imperiled fish species.
Discrete-Time Risk Models Based on Time Series for Count Random Variables
Authors: Cossette Hélène , Marceau Etienne , Maume-Deschamps Véronique
Published: June 2010

In this paper, we consider various specifications of the general discrete-time risk model in which a serial dependence structure is introduced between the claim numbers for each period. We consider risk models based on compound distributions assuming several examples of discrete variate time series as specific temporal dependence structures: Poisson MA(1) process, Poisson AR(1) process, Markov Bernoulli process and Markov regime-switching process. In these models, we derive expressions for a function that allow us to find the Lundberg coefficient. Specific cases for which an explicit expression can be found for the Lundberg coefficient are also presented. Numerical examples are provided to illustrate different topics discussed in the paper.
A Multilevel Analysis of Intercompany Claim Counts
Authors: Antonio Katrien , Frees Edward W. , Valdez Emiliano A.
Published: June 2010

It is common for professional associations and regulators to combine the claims experience of several insurers into a database known as an “intercompany” experience data set. In this paper, we analyze data on claim counts provided by the General Insurance Association of Singapore, an organization consisting of most of the general insurers in Singapore. Our data comes from the financial records of automobile insurance policies followed over a period of nine years. Because the source contains a pooled experience of several insurers, we are able to study company effects on claim behavior, an area that has not been systematically addressed in either the insurance or the actuarial literatures.

We analyze this intercompany experience using multilevel models. The multilevel nature of the data is due to: a vehicle is observed over a period of years and is insured by an insurance company under a “fleet” policy. Fleet policies are umbrella-type policies issued to customers whose insurance covers more than a single vehicle. We investigate vehicle, fleet and company effects using various count distribution models (Poisson, negative binomial, zero-inflated and hurdle Poisson). The performance of these various models is compared; we demonstrate how our model can be used to update a priori premiums to a posteriori premiums, a common practice of experience-rated premium calculations. Through this formal model structure, we provide insights into effects that company-specific practice has on claims experience, even after controlling for vehicle and fleet effects.
Determining and Allocating Diversification Benefits for a Portfolio of Risks
Authors: Choo Weihao , de Jong Piet
Published: June 2010

A critical problem in financial and insurance risk analysis is the calculation of risk margins. When there are a number of risks, the total risk margin is often reduced to reflect diversification. How large should the “diversification benefit” be? And how should the benefit be allocated to the individual risks? We propose a simple statistical solution. While providing a theoretical analysis, the final expressions are readily implemented in practice.
General Stein-Type Covariance Decompositions with Applications to Insurance and Finance
Authors: Furman Edward , Zitikis Ričardas
Published: June 2010

A general ‘multivariate’ decomposition of covariances is formulated and proved, and its role in the context of financial risk measurement and pricing is demonstrated.
The Complexity of Infinite Computations In Models of Set Theory
Authors: Finkel Olivier
Published: June 2010

We prove the following surprising result: there exist a 1-counter B\"uchi
automaton and a 2-tape B\"uchi automaton such that the \omega-language of the
first and the infinitary rational relation of the second in one model of ZFC
are \pi_2^0-sets, while in a different model of ZFC both are analytic but non
Borel sets.
This shows that the topological complexity of an \omega-language accepted by
a 1-counter B\"uchi automaton or of an infinitary rational relation accepted by
a 2-tape B\"uchi automaton is not determined by the axiomatic system ZFC.
We show that a similar result holds for the class of languages of infinite
pictures which are recognized by B\"uchi tiling systems.
We infer from the proof of the above results an improvement of the lower
bound of some decision problems recently studied by the author.
High-Fidelity Nursing Simulation: Impact on Student Self-Confidence and Clinical Competence
Authors: Blum Cynthia A , Borglund Susan , Parcells Dax
Published: June 2010

Development of safe nursing practice in entry-level nursing students requires special consideration from nurse educators. The paucity of data supporting high-fidelity patient simulation effectiveness in this population informed the development of a quasi-experimental, quantitative study of the relationship between simulation and student self-confidence and clinical competence. Moreover, the study reports a novel approach to measuring self-confidence and competence of entry-level nursing students. Fifty-three baccalaureate students, enrolled in either a traditional or simulation-enhanced laboratory, participated during their first clinical rotation. Student self-confidence and faculty perception of student clinical competence were measured using selected scale items of the Lasater Clinical Judgment Rubric. The results indicated an overall improvement in self-confidence and competence across the semester, however, simulation did not significantly enhance these caring attributes. The study highlights the need for further examination of teaching strategies developed to promote the transfer of self-confidence and competence from the laboratory to the clinical setting.
Computer simulation of rapid solidification with undercooling: A case study of spherical ceramics sample on metallic substrate
Authors: Nikolic Zoran , Yoshimura M.
Published: June 2010

Generally speaking, complex rapid solidification process kinetics can be solved by using numerical techniques only. In that sense, numerical methods for simulation of the solidification processes can be categorized as fixed-grid and interface tracking schemes, where the former ones cannot accurately track a sharp solid-liquid interface. Therefore, in this paper a numerical method based on control volume methodology and interface-tracking technique for computer simulation of rapid solidification accompanied by melt undercooling will be described and applied to analyze the solidification of a ceramic sample on a metallic substrate. A digital pyrometry system will be used for temperature measurement in an Arcimage furnace because of its merit of presenting data directly as temperature in real time with high accuracy. The characterization of solidification of a ceramic sample will be done by using the defined numerical method and inverse heat transfer analysis.
Thermal diffusivity of single crystal Bi0.9Sb0.1
Authors: Nikolic Pantelija , Vujatovic S.S. , Ivetic T. , Nikolic M.V. , Cvetkovic O. , Aleksic O.S. , Blagojevic V. , Brankovic G. , Nikolic N.
Published: June 2010

A single crystal Bi0.9Sb0.1 ingot was synthesized using the Bridgman technique. Thermal diffusivity and electronic transport properties of single crystal cleaved plates (00l) were determined from PA photoacoustic phase and amplitude spectra obtained using the photoacoustic method with a transmission detection configuration. Both the PA phase and amplitude were measured versus the modulation frequency and numerically analyzed. EDS analyses done to determine chemical composition of the studied samples as well as to check sample homogeneity. Hall effect measurements data were used for the photoacustic measurements.
Influence of structural transformations on electric and magnetic properties of Fe81B13Si4C2 amorphous alloy
Authors: Minic D.M. , Plazinic M. , Zivanic J. , Maricic A.
Published: June 2010

The structural transformations of the Fe81B13Si4C2 amorphous alloy under nonisothermal as well as under isothermal conditions were studied. The amorphous alloy was stable up to a temperature of about 450?C when the structural transformations began. The primary crystallization starts by forming Fe3Si as main phase (more than 80 wt %), and two minor phases Fe2B and Fe3B. With the increase of the temperature the phase composition as well as ratio of present phases is changed and above 600oC it was confirmed the presence only two stable phases, Fe3Si and Fe2B. It was shown that all observed structural transformations have significant influence on the electric and magnetic properties of alloy. The electric resistivity of the crystallized alloy is lower than the amorphous one. The crystallized alloy possesses better magnetic susceptibility and retains the ferromagnetic properties in whole investigated temperature range.
Eco-technological process of glass-ceramic production from galvanic sludge and aluminium slag
Authors: Stanisavljevic M. , Krstic I. , Zec S.
Published: June 2010

Methods of purification of waste water which are most commonly used in the Republic of Serbia belong to the type of conventional systems for purification such as chemical oxidation and reduction, neutralization, sedimentation, coagulation, and flocculation. Consequently, these methods generate waste sludge which, unless adequately stabilized, represents hazardous matter. The aluminium slag generated by melting or diecasting aluminium and its alloys is also hazardous matter. In this sense, this paper establishes ecological risk of galvanic waste sludge and aluminium slag and then describes the process of stabilization of these waste materials by means of transformation into a glass-ceramic structure through sintering. The obtained product was analyzed with Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray diffraction (XRD). The object of the paper is the eco-technological process of producing glass-ceramics from galvanic sludge and aluminium slag. The aim of the paper is to incorporate toxic metals from galvanic sludge and aluminium slag into the glass-ceramic product, in the form of solid solutions.