bluuebunny/crossref_metadata_2025 huggingface dataset:
Stand-level spatial dependence in an old-growth Jeffrey pine – mixed conifer forest, Sierra San Pedro Mártir, Mexico
Authors: Fry Danny L. , Stephens Scott L.
Published: September 2010

Descriptions of spatial patterns are important components of forest ecosystems, providing insights into functions and processes, yet basic spatial relationships between forest structures and fuels remain largely unexplored. We used standardized omnidirectional semivariance modeling to examine the spatial pattern of fuels and forest structure measured in a systematic nested plot grid covering 144 ha. Forest structure variables were spatially dependent at scales ranging from 62 to 572 m. Cross-variograms of fuels and forest structure showed both positive and negative correlations, ranging from 0.04 to 0.67. Notably, fine fuels were correlated positively and negatively with forest structure variables of white fir ( Abies concolor (Gord. & Glend.) Lindl. ex Hildebr.) and Jeffrey pine ( Pinus jeffreyi Balf.), respectively. Old-growth Jeffrey pine – mixed conifer forest within the study area exhibited both identifiable spatial correlations and high stand-level spatial heterogeneity, as demonstrated by the influence of outliers on the underlying spatial pattern. The spatial dependency of fuels with species-specific variables suggests that less common species may have a large influence in the characterization of forest attributes and that fuel classifications may be improved by accounting for the spatial distributions of overstory species. Spatial correlations have many applications to forest management, including the classification and mapping of forest structure, establishing guidelines for fuel treatments, and restoration of old-growth forest ecosystems.
SUPERCONFORMAL QUANTUM MECHANICS VIA WIGNER–HEISENBERG ALGEBRA
Authors: CARRION H. L. , DE LIMA RODRIGUES R.
Published: August 2010

We show the natural relation between the Wigner Hamiltonian and the conformal Hamiltonian. A model in (super)conformal quantum mechanics with (super)conformal symmetry in the Wigner–Heisenberg algebra picture [x, px] = i(1+cP) (P being the parity operator) is presented. In this context, the energy spectrum, the Casimir operator, raising and lowering operators are defined.
CROSSING THE PHANTOM DIVIDE WITH k-ESSENCE IN BRANEWORLDS
Authors: CHIMENTO LUIS P. , FORTE MÓNICA , RICHARTE MARTÍN G.
Published: August 2010

We study a flat three-brane in the presence of a linear k field with nonzero cosmological constant Λ4. In this model the crossing of the phantom divide (PD) occurs when the k-essence energy density becomes negative. We show that in the high energy regime the effective equation of state has a resemblance of a modified Chaplygin gas while in the low energy regime it becomes linear. We find a scale factor that begins from a singularity and evolves to a de Sitter stable stage while other solutions have a super-accelerated regime and end with a big rip. We use the energy conditions to show when the effective equation of state of the brane-universe crosses the PD.
AN ANALYSIS OF THE SUPPLY CURVE FOR LIQUIDITY RISK THROUGH BOOK DATA
Authors: BLAIS MARCEL , PROTTER PHILIP
Published: August 2010

We use order book data combined with tick data to analyze the supply curve models of liquidity issues in stock and option market trading. We show that supply curves really exist, and further that for highly liquid stocks they are linear. For slightly less liquid stocks the supply curve tends to be jump linear.
WHEN ARE SWING OPTIONS BANG-BANG?
Authors: BARDOU OLIVIER , BOUTHEMY SANDRINE , PAGÈS GILLES
Published: August 2010

In this paper we investigate a class of swing options with firm constraints in view of the modeling of supply agreements. We show, for a fully general payoff process, that the premium, solution to a stochastic control problem, is concave and piecewise affine as a function of the global constraints of the contract. The existence of bang-bang optimal controls is established for a set of constraints which generates by affinity the whole premium function. When the payoff process is driven by an underlying Markov process, we propose a quantization based recursive backward procedure to price these contracts. A priori error bounds are established, uniformly with respect to the global constraints.
EXACT PRICING WITH STOCHASTIC VOLATILITY AND JUMPS
Authors: D'IPPOLITI FERNANDA , MORETTO ENRICO , PASQUALI SARA , TRIVELLATO BARBARA
Published: August 2010

A stochastic volatility jump-diffusion model for pricing derivatives with jumps in both spot return and volatility underlying dynamics is presented. This model admits, in the spirit of Heston, a closed-form solution for European-style options. The structure of the model is also suitable to explicitly obtain the fair delivery price for variance swaps. To evaluate derivatives whose value does not admit a closed-form expression, a methodology based on an "exact algorithm", in the sense that no discretization of equations is required, is developed and applied to barrier options. Goodness of pricing algorithm is tested using DJ Euro Stoxx 50 market data for European options. Finally, the algorithm is applied to compute prices and Greeks for barrier options and to determine the fair delivery prices for variance swaps.
Epigenetics of programmed obesity: alteration in IUGR rat hepatic IGF1 mRNA expression and histone structure in rapid vs. delayed postnatal catch-up growth
Authors: Tosh Darran N. , Fu Qi , Callaway Christopher W. , McKnight Robert A. , McMillen Isabella C. , Ross Michael G. , Lane Robert H. , Desai Mina
Published: September 2010

Maternal food restriction (FR) during pregnancy results in intrauterine growth-restricted (IUGR) offspring that show rapid catch-up growth and develop metabolic syndrome and adult obesity. However, continued nutrient restriction during nursing delays catch-up growth and prevents development of obesity. Epigenetic regulation of IGF1, which modulates growth and is synthesized and secreted by the liver, may play a role in the development of these morbidities. Control (AdLib) pregnant rats received ad libitum food through gestation and lactation, and FR dams were exposed to 50% food restriction from days 10 to 21. FR pups were nursed by either ad libitum-fed control dams (FR/AdLib) or FR dams (FR/FR). All pups were weaned to ad libitum feed. Maternal FR resulted in IUGR newborns with significantly lower liver weight and, with the use of chromatin immunoprecipitation, decreased dimethylation at H3K4 in the IGF1 region was observed. Obese adult FR/AdLib males had decreased dimethylation and increased trimethylation of H3K4 in the IGF1 region. This corresponded to an increase in mRNA expression of IGF1-A (134 ± 5%), IGF1-B (165 ± 6%), IGF1 exon 1 (149 ± 6%), and IGF1 exon 2 (146 ± 7%) in the FR/AdLib compared with the AdLib/AdLib control group. In contrast, nonobese FR/FR had significantly higher IGF1-B mRNA levels (147 ± 19%) than controls with no difference in IGF1-A, exon 1 or exon 2. Modulation of the rate of IUGR newborn catch-up growth may thus protect against IGF1 epigenetic modifications and, consequently, obesity and associated metabolic abnormalities.
Radiomorphology of the Habib Sealer-Induced Resection Plane during Long-Time Followup:A Longitudinal Single Center Experience after 64 Radiofrequency-AssistedLiver Resections
Authors: Kleinert Robert , Wahba Roger , Bangard Christoph , Prenzel Klaus , Hölscher Arnulf H. , Stippel Dirk
Published: August 2010

Background. Radiofrequency (RF-) assisted liver resection devices like the Habib sealer induce a necrotic resection plane from which a small margin of necrotic liver tissue remains in situ. The aim of the present paper was to report our long-time experience with the new resection method and the morphological characteristics of the remaining necrotic resection plane. Methods. 64 RF-assisted liver resections were performed using the Habib sealer. Followup was assessed at defined time points. Results. The postoperative mortality was 3,6% and morbidity was 18%. The followup revealed that the necrotic zone was detectable in all analyzed CT and MRI images as a hypodense structure without any contrast enhancement at all time points, irrespectively of the time interval between resection and examination. Conclusion. Liver resection utilizing radiofrequency-induced resection plane coagulation is a safe alternative to the established resection techniques. The residual zone of coagulation necrosis remains basically unchanged during a followup of three years. This has to be kept in mind when evaluating the follow up imaging of these patients.
TLRs in Hepatic Cellular Crosstalk
Authors: Bigorgne Amelie E. , Crispe Ian Nicholas
Published: August 2010

Toll-like receptors (TLRs) are expressed on all major subsets of liver cells. Both exogenous ligands derived from pathogens, and endogenous ligands that are products of cellular injury, engage these receptors and activate aspects of innate immunity. These receptors play a role in viral and parasitic infections of the liver, in ischemia-reperfusion injury, and in toxic liver damage, promoting antipathogen immunity but also hepatocellular injury and fibrogenesis. However, TLRs may also participate in negative feedback that limits tissue injury. In the complex environment of the liver, TLRs participate in pathologic cascades involving multiple cell types, manifesting their effects both through cell-autonomous actions, and via cellular crosstalk. In this paper we survey the involvement of TLRs in these diverse processes.
In VivoEffects of Cagaita (Eugenia dysenterica, DC.) Leaf Extracts on Diarrhea Treatment
Authors: Lima T. B. , Silva O. N. , Silva L. P. , Rocha T. L. , Grossi-de-Sá M. F. , Franco O. L. , Leonardecz E.
Published: August 2010

Eugenia dysentericais a plant typically found in the Cerrado biome and commonly used in popular medicine due to its pharmacological properties, which include antidiarrheal, skin healing, and antimicrobial activities. The effects of ethanolic extract, aqueous extract and infusion ofE. dysentericaleaves on intestinal motility and antidiarrheal activity were evaluated using ricin oil‐induced diarrhea in rats. At doses of 400 and 800 mg·Kg−1, the ethanolic extract decreased intestinal motility while the other extracts showed no significant effects. Moreover, serum levels of chloride, magnesium, and phosphorus were also measured in rats. Histopathologic and enzymatic analyses were also performed to investigate any toxic effect. Animals treated with infusion, ethanolic extract, ricin oil, and loperamide presented morphological alterations in the small intestine, such as mucosa lesion, epithelial layer damage, and partial loss and/or morphological change of villi. Furthermore, the liver showed congestion and hydropic degeneration. Serum levels of alanine aminotransferase increased significantly in all treatments, but none rose above reference values. In summary, our results suggest that compounds present in leaves ofE. dysentericamay have therapeutic benefits on recovery from diarrhea despite their toxic effects.
IFN Induces miR-21 through a Signal Transducer and Activator of Transcription 3–Dependent Pathway as a Suppressive Negative Feedback on IFN-Induced Apoptosis
Authors: Yang Chuan He , Yue Junming , Fan Meiyun , Pfeffer Lawrence M.
Published: September 2010

The microRNA miR-21 is overexpressed in many human cancers, wherein accumulating evidence indicates that it functions as an oncogene. Here, we report that the cytokine IFN rapidly induces miR-21 expression in human and mouse cells. Signal transducer and activator of transcription 3 (STAT3) was implicated in this pathway based on the lack of IFN effect on miR-21 expression in prostate cancer cells with a deletion in the STAT3 gene. STAT3 ablation abrogated IFN induction of miR-21, confirming the important role of STAT3 in regulating miR-21. Chromatin immunoprecipitation analysis showed that STAT3 directly bound the miR-21 promoter in response to IFN. Experiments in mouse embryo fibroblasts with a genetic deletion of the p65 NF-κB subunit showed that IFN-induced miR-21 expression was also dependent on NF-κB. STAT3 silencing blocked both IFN-induced p65 binding to the miR-21 promoter and p65 nuclear translocation. Thus, IFN-induced miR-21 expression is coregulated by STAT3 and NF-κB at the level of the miR-21 promoter. Several cell death regulators were identified as downstream targets of miR-21, including PTEN and Akt. Functional experiments in prostate cancer cells directly showed that miR-21 plays a critical role in suppressing IFN-induced apoptosis. Our results identify miR-21 as a novel IFN target gene that functions as a key feedback regulator of IFN-induced apoptosis. Cancer Res; 70(20); 8108–16. ©2010 AACR.
The European Disorder of Sex Development Registry: A Virtual Research Environment
Authors: Ahmed S.F. , Rodie M. , Jiang J. , Sinnott R.O.
Published: September 2010

Disorders of sex development (DSD) are a rare group of conditions which require further research. Effective research into understanding the aetiology, as well as long-term outcome of these rare conditions, requires multicentre collaboration often across national boundaries. The EU-funded EuroDSD programme (www.eurodsd.eu) is one such collaboration involving clinical centres and clinical and genetic experts across Europe. At the heart of the EuroDSD collaboration is a European DSD registry and a targeted virtual research environment (VRE) that supports the sharing of DSD data. Security, ethics and information governance are cornerstones of this infrastructure. This paper describes the infrastructure that has been developed, the inherent challenges in security, availability and dependability that must be overcome for the enterprise to succeed and provides a sample of the data that are stored in the registry along with a summary analysis of the current data sets.
Hyaluronan Used for Intradermal Injections Is Incorporated into the Pericellular Matrix and Promotes Proliferation in Human Skin Fibroblasts in vitro
Authors: Röck Katharina , Fischer Kerstin , Fischer Jens W.
Published: September 2010

Background: Over the past decade injectable hyaluronan (HA) formulations have been widely used to decrease the visibility of skin aging. However, little basic research has been performed to address their effect on dermal skin fibroblasts. Objective: The aim of the present study was to investigate whether human skin fibroblasts are affected by exogenous non-cross-linked HA with respect to proliferation, migration and extracellular matrix composition. Methods: The effect of a non-cross-linked HA on proliferation, migration and gene expression of human dermal fibroblasts was determined. Furthermore, affinity histochemistry of pericellular HA was performed. Results: Proliferation was significantly stimulated by HA whereas migration was not affected. Importantly, exogenous HA was incorporated into fine HA filaments of the pericellular fibroblast matrix. Conclusion: This is the first evidence that a HA formulation used in humans for cosmetic reasons stimulates fibroblast proliferation and is utilized to assemble a supramolecular pericellular structure.
Influenza in the Elderly – A Mini-Review
Authors: Pop-Vicas A. , Gravenstein S.
Published: September 2010

Influenza is an important cause of morbidity and mortality in the elderly population each year. The often subtle clinical manifestations in the frail geriatric patients may not be recognized initially, impeding timely administration of antiviral treatment. The effectiveness of current influenza vaccines in the elderly population is often diminished by immune senescence. Increasing immunization rates among health-care workers and elderly caregivers, and finding more effective vaccines for the elderly people are likely to significantly improve disease prevention in this population at risk.
Pitch Range Variation in English Tonal Contrasts: Continuous or Categorical?
Authors: Dilley Laura C.
Published: September 2010

The importance of pitch range variation for intonational meaning and theory is well known; however, whether pitch range is a phonetic dimension which is treated categorically in English remains unclear. To test this possibility, three intonation continua varying in pitch range were constructed which had endpoints with contrastive representations under autosegmental-metrical (AM) theory: H* vs. L+H*, H* with ‘peak delay’ vs. L*+H, and %H L* vs. L*. The prediction derived from AM theory was that the reproduction of continuous pitch range variation should show a discrete pattern reflecting a change in the phonological representation of tonal sequences and in the number of tonal targets across each continuum. Participants’ reproductions of each stimulus set showed continuous variation in pitch range, suggesting that pitch range is a gradient phonetic dimension in English conveying semantic contrast, similar to the formant space for vowels. Moreover, the gradience observed in productions across all parts of the pitch range suggests that contours within each series had the same number of tonal targets. The results support a version of AM theory in which rises and falls are usually comprised of two tonal targets, with strictly monotonic f₀ interpolation between them.
Indications for Endoscopic or Surgical Treatment of Chronic Pancreatitis
Authors: Rieder Simon , Michalski Christoph W. , Friess Helmut
Published: September 2010

In patients suffering from chronic pancreatitis, pain as the predominant symptom remains a therapeutic challenge which often cannot be tackled conservatively. Since pancreatic duct obstruction – frequently within the pancreatic head – is an important etiological factor, treatment in these cases aims at decompressing the duct either endoscopically or surgically. Endoscopic drainage includes sphincterotomy, dilation of strictures, removal of stones, and insertion of a stent; it has a success rate of 30–100%. Surgical treatment may be accomplished by drainage or resection procedures. Drainage procedures (such as the longitudinal opening of the pancreatic duct followed by a pancreaticojejunostomy) can be performed with a low rate of postoperative complications (6–30%) and mortality (0–2%), and can achieve long-term pain relief in 65–85% of the cases. Furthermore, there are a variety of resection procedures such as pancreaticoduodenenectomy (Whipple procedure), pylorus-preserving pancreaticoduodenenectomy, different types of the duodenum-preserving pancreatic head resection (i.e. Beger, Frey, or Büchler procedures), segmentectomy, and V-shaped excision of the pancreatic duct. However, the surgical procedure of choice is controversially discussed. While it has been shown that parenchyma-preserving surgery is superior to more extensive resections, it remains unclear which of the modifications of the parenchyma-sparing procedures is suited best for which case. Recently, two randomized controlled trials have demonstrated that surgical treatment is superior to endotherapy in long-term pain reduction, physical health score results, and the number of reinterventions. Thus, in patients with chronic pancreatitis refractory to conservative medical treatment, surgery rather than endotherapy is the standard of care. Parenchyma-preserving resections should preferably be performed because they ensure lower morbidity and mortality, preserve endocrine function, and improve quality of life.
Diagnosis of Chronic Pancreatitis
Authors: Beglinger Christoph
Published: September 2010

The diagnosis of chronic pancreatitis is based on a typical history with recurrent flares of acute inflammation, imaging procedures and some laboratory tests. Using imaging procedures (abdominal ultrasound, computed tomography or magnetic resonance imaging), a diagnosis can only be made when alterations in size (enlargement or atrophy) or shape of the pancreas or changes in intrapancreatic structure (dilation, obstruction of ducts), calcifications, or changes in peripancreatic organs have occurred. Tests of exocrine pancreatic function are not essential for making a diagnosis of chronic pancreatitis.
Leptin Responsiveness of Mice Deficient in Corticotrophin-Releasing Hormone Receptor Type 2
Authors: Harris Ruth B.S.
Published: September 2010

Leptin acts centrally to inhibit food intake and increase energy expenditure. Corticotrophin-releasing hormone (CRH) is one of the neuropeptides that may contribute to leptin-induced hypophagia and thermogenesis. Acute leptin administration increases CRH mRNA expression in the paraventricular nucleus of the hypothalamus and CRH receptor type 2 (CRHR2) expression in the ventromedial nucleus of the hypothalamus. Studies described here used male and female CRHR2 knockout (KO) mice and wild-type (WT) controls to test the importance of CRHR2 in mediating the effects of leptin on food intake, weight gain and body composition. Peripheral injections of 0.5 mg/kg leptin for 3 days inhibited food intake in female WT and male KO mice, but inhibited weight gain in female KO and male WT mice suggesting an important role for thermogenesis in mediating weight loss. A single third ventricle injection of 1 µg leptin inhibited 12 h food intake of all mice, 36 h cumulative intake of KO mice and weight loss in WT and KO female and WT male mice. A 12-day peripheral infusion of 10 µg leptin/day had no effect on food intake of any group, but significantly reduced carcass fat and protein content of all mice. These results indicate that CRHR2 are not essential for the effects of leptin on food intake, body weight or body composition. Leptin response seems to be determined by a combination of mouse gender and genotype, but CRHR2 KO mice may have an extended response to central leptin injections compared with their WT controls.
Involvement of the Basilar Artery in Diabetes Mellitus: An MRI Study of Brainstem Infarctions
Authors: Ichikawa Hiroo , Mukai Masanori , Hieda Soutaro , Kamiya Yuki , Akizawa Tadao , Kawamura Mitsuru
Published: September 2010

The relationships among diabetes mellitus (DM), brainstem infarctions (BSIs) and involvement of the basilar artery (BA) were investigated in 254 patients with acute cerebral infarctions detected on magnetic resonance (MR) imaging. Radiological findings included lesion topography and size (mm2) of BSIs on MR images, and the extent of BA stenosis measured by MR angiography. Adjusted logistic regression analyses showed that DM (OR 4.018; p = 0.0006) and BA stenosis (OR 1.003 per 1 mm; p < 0.0001) had an independent association with the incidence of BSIs, but the lesion size of the BSIs was only associated with BA stenosis (β coefficient 0.280; p < 0.0001). Diabetic patients showed significantly more frequent isolated pontine infarctions and a lesser degree of BA stenosis (p < 0.005) compared to non-diabetic patients. Preferential involvement of the pons and smaller vessels may be characteristics of diabetic patients.
Peroxisome Proliferator-Activated Receptor-γ Agonist Rosiglitazone Prevents Albuminuria but Not Glomerulosclerosis in Experimental Diabetes
Authors: Setti Giorgia , Hayward Anthea , Dessapt Cecile , Barone Francesca , Buckingham Robin , White Kathryn , Bilous Rudolf , Hiroshi Kawachi , Gruden Gabriella , Viberti GianCarlo , Gnudi Luigi
Published: September 2010

Backgrounds/Aims:Renal inflammation and nephrin downregulation contribute to albuminuria in diabetes. We studied, in streptozotocin-induced diabetic rats, the effect of rosiglitazone (RSG), a peroxisome proliferator-activated receptor-γ agonist, on renal macrophage infiltration, MCP1, and nephrin expression in relation to albuminuria. Methods: We investigated control and diabetic rats treated or untreated with RSG. Animals were sacrificed at 1, 3, and 9 months. Renal MCP1 and nephrin expression were studied by immunoblotting, renal macrophage infiltration by immunohistochemistry, and albuminuria by ELISA. Electron microscopy was used to assess glomerular ultrastructural morphology. In vitroexperiments were conducted in isolated cultured rat glomeruli. Results: Glycaemic control was similar in diabetic rats treated and untreated with RSG, and blood pressure was comparable in all groups. RSG prevented diabetes-induced albuminuria at 9 months, and renal macrophage infiltration and MCP1 upregulation at 3 and 9 months. Diabetes-mediated nephrin downregulation was abolished by RSG. Diabetes-induced glomerulosclerosis, glomerular basement membrane thickening, and foot process fusion were not affected by RSG. In isolated glomeruli, MCP1 directly induced nephrin downregulation and this was prevented by RSG. RSG had no effect on nephrin expression. Conclusion: RSG prevents albuminuria and nephrin downregulation in experimental diabetes independently of glycaemic and blood pressure control. This effect likely occurs via correction of diabetes-induced inflammatory processes.
β2-Microglobulin, Pulse Pressure and Metabolic Alterations in Hemodialysis Patients
Authors: Raikou Vaia D. , Tentolouris Nicholas , Kyriaki Despina , Evaggelatou Anastasia , Tzanatou Helen
Published: September 2010

Background/Aim: Pulse pressure (PP) is a result of arterial stiffness seen in dialysis patients, but may be a consequence of fluid overload. We examined the role of β2-microglobulin (β2M) in PP in relation to metabolic alterations in patients on different hemodialysis (HD) modalities. Methods: We studied 76 hemodialyzed patients on regular HD (n = 34), predilution bagged hemodiafiltration (n = 19) and online predilution hemodiafiltration (n = 23). β2M levels were measured by radioimmunoassay, and the clearance of β2M was assessed by Kt/V for β2M. Arterial stiffness was measured as carotid-femoral pulse wave velocity, and PP was derived. Insulin levels were measured using immunoradioassay, and insulin resistance was calculated using homeostasis model assessment insulin resistance (HOMA-IR). Serum bicarbonate levels were measured using a blood gas analyzer, and percent sodium removal was calculated. Results: β2M levels predict increased PP (p = 0.02) adjusting for age, HD modalities, HD duration, HOMA-IR and percent sodium removal. β2M was positively associated with HOMA-IR (r = 0.306, p = 0.007). Serum bicarbonate levels and carotid-femoral pulse wave velocity were inversely associated (r = –0.719, p = 0.001). Conclusions: β2M levels were positively associated with PP, which was influenced mainly by dialysis modality fluid and sodium balance and less by arterial stiffness. β2M levels were positively associated with insulin resistance. Uremic acidosis may contribute to arterial stiffness.
Do Changes in Relative Blood Volume Monitoring Correlate to Hemodialysis-Associated Hypotension?
Authors: Booth John , Pinney Jennifer , Davenport Andrew
Published: September 2010

Introduction: Intradialytic hypotension remains the most common complication for outpatient hemodialysis, and relative blood volume monitoring was designed to reduce hypotension. Reports of the usefulness of this technology, however, have been variable. Methods: We audited the usefulness of relative blood volume monitoring recorded throughout the mid-week dialysis in 72 stable adult outpatients who had multifrequency bioimpedance measurements. Results: The blood volume measurement (BVM) at the end of the session was 91.6 ± 0.6% and was not different from the nadir BVM recorded (90.7 ± 0.5). The BVM was strongly correlated with change in hematocrit (r = –0.56, p < 0.001) and albumin (r = –0.69, p < 0.001), but had no relationship with pre-, intra- or postdialysis blood pressure recordings. The BVM was not associated with ultrafiltration volume, but did correlate with a postdialysis change in extracellular fluid volume (r = –0.39, p = 0.006). Conclusion: In this audit, although the BVM at the end of the dialysis session was correlated with changes in hematocrit, serum albumin and extracellular fluid volume, the change in the relative BVM did not mirror changes in intradialytic blood pressure.
Serum Biological Antioxidant Potential Predicts the Prognosis of Hemodialysis Patients
Authors: Ishii Tomoko , Ohtake Takayasu , Okamoto Koji , Mochida Yasuhiro , Ishioka Kunihiro , Oka Machiko , Maesato Kyoko , Ikee Ryota , Moriya Hidekazu , Hidaka Sumi , Doi Kent , Noiri Eisei , Fujita Toshiro , Kobayashi Shuzo
Published: September 2010

Background: It is well known that oxidative stress is enhanced in patients with end-stage renal disease. However, little is known about the relationship between serum antioxidant capacity and clinical outcome in hemodialysis (HD) patients. Methods: We examined the relationship between serum biomarkers of oxidative stress and clinical outcomes including all-cause mortality, hospitalization rate and incidence of cardiovascular events in HD patients. As biomarkers of oxidative stress, we measured serum levels of coenzyme Q10 (CoQ10) and biological antioxidant potential (BAP). Results: 108 patients were observed for 30 months as the follow-up periods. The survival group (n = 83) showed significantly higher BAP values compared with those in death groups (n = 25; p < 0.05). When serum BAP levels were divided into two groups by their median value, the group with higher BAP values had a better survival rate than that with lower BAP values on the Kaplan-Meier survival analysis (p = 0.05). Although serum levels of CoQ10 did not show any association with clinical outcomes, lower BAP was selected as an independent risk factor for all-cause mortality as well as the absence of angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers therapy by age-adjusted Cox regression analysis. Conclusions: This study indicated that BAP could predict the prognosis of HD patients.
Transient Receptor Potential Melastatin 6 Knockout Mice Are Lethal whereas Heterozygous Deletion Results in Mild Hypomagnesemia
Authors: Woudenberg-Vrenken Titia E. , Sukinta Arjaree , van der Kemp Annemiete W. , Bindels René J.M. , Hoenderop Joost G.J.
Published: September 2010

Background: Hypomagnesemia with secondary hypocalcemia is due to disturbed renal and intestinal magnesium (Mg2+) (re)absorption. The underlying defect is a mutation in the transient receptor potential melastatin type 6 (TRPM6), a Mg2+-permeable ion channel expressed in the kidney and intestine. Our aim was to characterize homozygous (–/–) and heterozygous (+/–) TRPM6 knockout mice with respect to Mg2+ homeostasis. Methods: TRPM6+/– mice were bred on a normal (0.19% wt/wt Mg2+) and high (0.48% wt/wt Mg2+) Mg2+ diet. In the offspring, 24-hour urinary Mg2+ and calcium excretion as well as serum concentrations of both were determined. TRPM6 mRNA expression in the kidney and colon was measured. Results: On the regular diet, 30% of the offspring were TRPM6 wild-type (+/+), 70% were TRPM6+/–, and none were TRPM6–/–. The genotypic distribution of the litters remained the same on the 0.48% Mg2+ diet. In TRPM6+/– mice on both diets, serum Mg2+ levels were significantly lower, and renal and intestinal TRPM6 mRNA expression was reduced. Urinary Mg2+ excretion was unaffected. Conclusions: Homozygous TRPM6 deletion is embryonic lethal in mice. Heterozygous deletion of TRPM6 results in a mild hypomagnesemia. The Mg2+-enriched diet could not compensate for either embryonic lethality or hypomagnesemia caused by TRPM6 deficiency.
Receptor Activity-Modifying Protein-1 Augments Cerebrovascular Responses to Calcitonin Gene-Related Peptide and Inhibits Angiotensin II-Induced Vascular Dysfunction
Authors: Chrissobolis Sophocles , Zhang Zhongming , Kinzenbaw Dale A. , Lynch Cynthia M. , Russo Andrew F. , Faraci Frank M.
Published: September 2010

Background and Purpose—

Receptors for calcitonin gene-related peptide (CGRP) are composed of the calcitonin-like receptor in association with receptor activity-modifying protein-1 (RAMP1). CGRP is an extremely potent vasodilator and may protect against vascular disease through other mechanisms.

Methods—

We tested the hypothesis that overexpression of RAMP1 enhances vascular effects of CGRP using transgenic mice with ubiquitous expression of human RAMP1. Because angiotensin II (Ang II) is a key mediator of vascular disease, we also tested the hypothesis that RAMP1 protects against Ang II-induced vascular dysfunction.

Results—

Responses to CGRP in carotid and basilar arteries in vitro as well as cerebral arterioles in vivo were selectively enhanced in human RAMP1 transgenic mice compared to littermate controls (
P
<0.05), and this effect was prevented by a CGRP receptor antagonist (
P
<0.05). Thus, vascular responses to CGRP are normally RAMP1-limited. Responses of carotid arteries were examined in vitro after overnight incubation with vehicle or Ang II. In arteries from control mice, Ang II selectively impaired responses to the endothelium-dependent agonist acetylcholine by ≈50% (
P
<0.05) via a superoxide-mediated mechanism. In contrast, Ang II did not impair responses to acetylcholine in human RAMP1 transgenic mice.

Conclusions—

RAMP1 overexpression increases CGRP-induced vasodilation and protects against Ang II-induced endothelial dysfunction. These findings suggest that RAMP1 may be a new therapeutic target to regulate CGRP-mediated effects during disease including pathophysiological states in which Ang II plays a major role.
Common Carotid Intima-Media Thickness and Framingham Risk Score Predict Incident Carotid Atherosclerotic Plaque Formation
Authors: von Sarnowski Bettina , Lüdemann Jan , Völzke Henry , Dörr Marcus , Kessler Christof , Schminke Ulf
Published: September 2010

Background and Purpose—

Cross-sectional studies describe a positive association between common carotid artery intima-media thickness (CCA-IMT) and carotid plaques (CP). However, longitudinal data on the predictive value of CCA-IMT for occurrence of CP are limited. Therefore, the role of increasing CCA-IMT in the atherosclerotic process is still discussed controversially.

Methods—

We investigated the predictive value of CCA-IMT and the Framingham risk score (FRS) for incident CP formation in a population-based longitudinal study of 1922 subjects aged 45 to 81 years who underwent ultrasonography of both carotid arteries and received vascular risk factor assessment at baseline and after 5 years. CP was defined as any protruding focal thickening of the intima-media complex. Incident CP formation during follow-up was defined as the appearance of at least 1 CP in a previously plaque-free arterial segment (right and left common, internal, and external carotid arteries and carotid bifurcation).

Results—

Among the 636 subjects without CP at baseline, 418 (66%) had at least 1 incident CP during follow-up. In a multivariable negative binominal regression model adjusted for age, gender, and the FRS, the number of arterial segments affected by incident CP was 1.53-fold higher (CI, 1.12–2.07;
P
<0.01) for subjects in the highest quartile of the overall CCA-IMT distribution compared to those in the lowest quartile.

Conclusions—

Both CCA-IMT and FRS independently predict incident CP formation. The risk of CP formation may actually be underestimated in subjects with low FRS and high IMT.
A Conditional Entropy Minimization Criterion for Dimensionality Reduction and Multiple Kernel Learning
Authors: Hino Hideitsu , Murata Noboru
Published: August 2010

Reducing the dimensionality of high-dimensional data without losing its essential information is an important task in information processing. When class labels of training data are available, Fisher discriminant analysis (FDA) has been widely used. However, the optimality of FDA is guaranteed only in a very restricted ideal circumstance, and it is often observed that FDA does not provide a good classification surface for many real problems. This letter treats the problem of supervised dimensionality reduction from the viewpoint of information theory and proposes a framework of dimensionality reduction based on class-conditional entropy minimization. The proposed linear dimensionality-reduction technique is validated both theoretically and experimentally. Then, through kernel Fisher discriminant analysis (KFDA), the multiple kernel learning problem is treated in the proposed framework, and a novel algorithm, which iteratively optimizes the parameters of the classification function and kernel combination coefficients, is proposed. The algorithm is experimentally shown to be comparable to or outperforms KFDA for large-scale benchmark data sets, and comparable to other multiple kernel learning techniques on the yeast protein function annotation task.
Rademacher Chaos Complexities for Learning the Kernel Problem
Authors: Ying Yiming , Campbell Colin
Published: August 2010

We develop a novel generalization bound for learning the kernel problem. First, we show that the generalization analysis of the kernel learning problem reduces to investigation of the suprema of the Rademacher chaos process of order 2 over candidate kernels, which we refer to as Rademacher chaos complexity. Next, we show how to estimate the empirical Rademacher chaos complexity by well-established metric entropy integrals and pseudo-dimension of the set of candidate kernels. Our new methodology mainly depends on the principal theory of U-processes and entropy integrals. Finally, we establish satisfactory excess generalization bounds and misclassification error rates for learning gaussian kernels and general radial basis kernels.
The Neuronal Replicator Hypothesis
Authors: Fernando Chrisantha , Goldstein Richard , Szathmáry Eörs
Published: August 2010

We propose that replication (with mutation) of patterns of neuronal activity can occur within the brain using known neurophysiological processes. Thereby evolutionary algorithms implemented by neuro- nal circuits can play a role in cognition. Replication of structured neuronal representations is assumed in several cognitive architectures. Replicators overcome some limitations of selectionist models of neuronal search. Hebbian learning is combined with replication to structure exploration on the basis of associations learned in the past. Neuromodulatory gating of sets of bistable neurons allows patterns of activation to be copied with mutation. If the probability of copying a set is related to the utility of that set, then an evolutionary algorithm can be implemented at rapid timescales in the brain. Populations of neuronal replicators can undertake a more rapid and stable search than can be achieved by serial modification of a single solution. Hebbian learning added to neuronal replication allows a powerful structuring of variability capable of learning the location of a global optimum from multiple previously visited local optima. Replication of solutions can solve the problem of catastrophic forgetting in the stability-plasticity dilemma. In short, neuronal replication is essential to explain several features of flexible cognition. Predictions are made for the experimental validation of the neuronal replicator hypothesis.
No evidence for strategic male mating effort in response to female weight in a bushcricket
Authors: Reinhold Klaus , Sevgili Hasan
Published: September 2010

Theoretical models predict that males should allocate sperm in response to female quality and empirical studies have shown that fecundity traits including age, mass and mating status can influence male sperm allocation strategies. We tested whether female size has an influence on sperm allocation in the bushcricket Poecilimon jonicus jonicus (Orthoptera: Phaneropterinae). Contrary to other studies, we found neither evidence of strategic sperm allocation in response to female size nor an effect of female size on spermatophore size. Male age and mating history was positively related to sperm number during sequential matings, but had no effect on spermatophylax or ampulla weight. Spermatophore weight, but not sperm number, was positively correlated with male body weight. Ampulla weight was positively correlated with spermatophylax weight.
Challenges in Regional-Scale Climate Modeling
Authors: Arritt Raymond W. , Rummukainen Markku
Published: September 2010

No abstract available.
Attenuation and Differential Attenuation of 5-cm-Wavelength Radiation in Melting Hail
Authors: Borowska L. , Ryzhkov A. , Zrnić D. , Simmer C. , Palmer R.
Published: September 2010

Presented are quantitative estimates of specific attenuation and specific differential attenuation of 5-cm-wavelength radiation (C band) obtained by comparison with measurements at 10-cm wavelength (S band), which are much less affected by attenuation. The data originated from two almost-collocated radars in central Oklahoma. To avoid biases in estimates, the slopes with respect to range of differences in reflectivities and differential reflectivities are assumed to represent the specific attenuations. Observations on a day with no reports of hail on the ground and on a day with large hail are contrasted. A simple one-dimensional model of melting hail is used to qualify these observations. Examples of volumetric fields of the polarimetric variables obtained at the two wavelengths are presented to illustrate that much can be learned about size, orientation, and phase of hydrometeors over volumes that play a role in precipitation formation.
Large-Eddy Simulation of Post-Cold-Frontal Continental Stratocumulus
Authors: Mechem David B. , Kogan Yefim L. , Schultz David M.
Published: September 2010

Previous large-eddy simulations (LES) of stratocumulus-topped boundary layers have been exclusively set in marine environments. Boundary layer stratocumulus clouds are also prevalent over the continent but have not been simulated previously. A suite of LES runs was performed for a case of continental post-cold-frontal stratocumulus observed by the Atmospheric Radiation Measurement Program (ARM) Climate Research Facility (ACRF), located in northern Oklahoma. Comparison with fixed, ground-based sensors necessitated an Eulerian approach in which it was necessary to supply to the model estimates of synoptic-scale advection and vertical motion, particularly given the quickly evolving, baroclinic nature of the synoptic environment. Initial analyses from the Rapid Update Cycle model supplied estimates for these forcing terms.

Turbulent statistics calculated from the LES results are consistent with large-eddy observations obtained from millimeter-wave cloud radar. The magnitude of turbulence is weaker than in typical marine stratocumulus, a result attributed to highly decoupled cloud and subcloud circulations associated with a deep layer of negative buoyancy flux arising from the entrainment of warm, free-tropospheric air. Model results are highly sensitive to variations in advection of temperature and moisture and much less sensitive to changes in synoptic-scale vertical velocity and surface fluxes. For this case, moisture and temperature advection, rather than entrainment, tend to be the governing factors in the analyzed cloud system maintenance and decay. Typical boundary layer entrainment scalings applied to this case do not perform very well, a result attributed to the highly decoupled nature of the circulation. Shear production is an important part of the turbulent kinetic energy budget. The dominance of advection provides an optimistic outlook for mesoscale, numerical weather prediction, and climate models because these classes of models represent these grid-scale processes better than they do subgrid-scale processes such as entrainment.
The Vertical Distribution of Radon in Clear and Cloudy Daytime Terrestrial Boundary Layers
Authors: Williams Alastair G. , Zahorowski Wlodek , Chambers Scott , Griffiths Alan , Hacker Jörg M. , Element Adrian , Werczynski Sylvester
Published: September 2010

Radon (222Rn) is a powerful natural tracer of mixing and exchange processes in the atmospheric boundary layer. The authors present and discuss the main features of a unique dataset of 50 high-resolution vertical radon profiles up to 3500 m above ground level, obtained in clear and cloudy daytime terrestrial boundary layers over an inland rural site in Australia using an instrumented motorized research glider. It is demonstrated that boundary layer radon profiles frequently exhibit a complex layered structure as a result of mixing and exchange processes of varying strengths and extents working in clear and cloudy conditions within the context of the diurnal cycle and the synoptic meteorology. Normalized aircraft radon measurements are presented, revealing the characteristic structure and variability of three major classes of daytime boundary layer: 1) dry convective boundary layers, 2) mixed layers topped with residual layers, and 3) convective boundary layers topped with coupled nonprecipitating clouds. Robust and unambiguous signatures of important atmospheric processes in the boundary layer are identifiable in the radon profiles, including “top-down” mixing associated with entrainment in clear-sky cases and strongly enhanced venting and subcloud-layer mixing when substantial active cumulus are present. In poorly mixed conditions, radon gradients in the daytime atmospheric surface layer significantly exceed those predicted by Monin–Obukhov similarity theory. In two case studies, it is demonstrated for the first time that a sequence of vertical radon profiles measured over the course of a single day can consistently reproduce major structural features of the evolving boundary layer.
The Influence of Stratification and Nonlocal Turbulent Production on Estuarine Turbulence: An Assessment of Turbulence Closure with Field Observations
Authors: Scully Malcolm E. , Geyer W. Rocky , Trowbridge John H.
Published: August 2010

Field observations of turbulent kinetic energy (TKE), dissipation rate ɛ, and turbulent length scale demonstrate the impact of both density stratification and nonlocal turbulent production on turbulent momentum flux. The data were collected in a highly stratified salt wedge estuary using the Mobile Array for Sensing Turbulence (MAST). Estimates of the dominant length scale of turbulent motions obtained from the vertical velocity spectra provide field confirmation of the theoretical limitation imposed by either the distance to the boundary or the Ozmidov scale, whichever is smaller. Under boundary-limited conditions, anisotropy generally increases with increasing shear and decreased distance to the boundary. Under Ozmidov-limited conditions, anisotropy increases rapidly when the gradient Richardson number exceeds 0.25. Both boundary-limited and Ozmidov-limited conditions demonstrate significant deviations from a local production–dissipation balance that are largely consistent with simple scaling relationships for the vertical divergence in TKE flux. Both the impact of stratification and deviation from equilibrium turbulence observed in the data are largely consistent with commonly used turbulence closure models that employ “nonequilibrium” stability functions. The data compare most favorably with the nonequilibrium version of the L. H. Kantha and C. A. Clayson stability functions. Not only is this approach more consistent with the observed critical gradient Richardson number of 0.25, but it also accounts for the large deviations from equilibrium turbulence in a manner consistent with the observations.
The Peruvian Diaspora
Authors: Durand Jorge
Published: September 2010

Since the 1980s and especially the 1990s, Peru has become a nation of emigrants. Emigration has become massive over the past two decades, and the Peruvian populations of the United States, Japan, and Spain have tripled in less than a decade. A survey of households in five localities, three urban and two rural, in and around Lima helps to reveal the special character of this emigration. It tends to involve older and better-educated individuals than are typical of international migration and to target a wider variety of destinations. Moreover, it is a multiclass phenomenon. The economic, political, and social crisis brought about by a change in the economic model, two decades of terrorism, and a succession of failed democratic administrations has affected the society as a whole, and international migration seems to operate as an escape valve.