bluuebunny/crossref_metadata_2025 huggingface dataset:
Endogenous angiotensin II facilitates GABAergic neurotransmission afferent to the Na+-responsive neurons of the rat median preoptic nucleus
Authors: Henry Mélaine , Grob Magali , Mouginot Didier
Published: July 2009

The median preoptic nucleus (MnPO) is densely innervated by efferent projections from the subfornical organ (SFO) and, therefore, is an important relay for the peripheral chemosensory and humoral information (osmolality and serum levels ANG II). In this context, controlling the excitability of MnPO neuronal populations is a major determinant of body fluid homeostasis and cardiovascular regulation. Using a brain slice preparation and patch-clamp recordings, our study sought to determine whether endogenous ANG II modulates the strength of the SFO-derived GABAergic inputs to the MnPO. Our results showed that the amplitude of the inhibitory postsynaptic currents (IPSCs) were progressively reduced by 44 ± 2.3% by (Sar1, Ile8)-ANG II, a competitive ANG type 1 receptor (AT1R) antagonist. Similarly, losartan, a nonpeptidergic AT1R antagonist decreased the IPSC amplitude by 40.4 ± 5.6%. The facilitating effect of endogenous ANG II on the GABAergic input to the MnPO was not attributed to a change in GABA release probability and was mimicked by exogenous ANG II, which potentiated the amplitude of the muscimol-activated GABAA/Cl− current by 53.1 ± 11.4%. These results demonstrate a postsynaptic locus of action of ANG II. Further analysis reveals that ANG II did not affect the reversal potential of the synaptic inhibitory response, thus privileging a cross talk between postsynaptic AT1 and GABAA receptors. Interestingly, facilitation of GABAergic neurotransmission by endogenous ANG II was specific to neurons responding to changes in the ambient Na+ level. This finding, combined with the ANG II-mediated depolarization of non-Na+-responsive neurons reveals the dual actions of ANG II to modulate the excitability of MnPO neurons.
Age-dependent regression analysis of male gonadal axis
Authors: Keenan Daniel M. , Veldhuis Johannes D.
Published: July 2009

The mechanisms by which aging progressively depletes testosterone (Te) availability in the male are unknown. Accordingly, the objective was to estimate brain gonadotropin-releasing hormone (GnRH) outflow (release and action), which cannot be observed directly, on the basis of downstream effects on pituitary luteinizing hormone (LH) secretion. LH, in turn, feeds forward on (stimulates) gonadal Te secretion, which then feeds back on (inhibits) GnRH-driven LH secretion. LH and Te concentrations were measured repetitively (every 10 min) over 18 h during graded pharmacological blockade of endogenous GnRH outflow in 24 healthy 20- to 72-yr-old men. Data were analyzed using a new age-dependent regression model of GnRH-LH-Te interactions to estimate pulsatile LH secretion and elimination, GnRH outflow, LH feedforward, and Te feedback. By incorporating regression on age within the dose-response model, we show that aging erodes all three primary forward and reverse pathways linking the brain, pituitary gland, and testes. Aging is associated with concomitant deficits in GnRH → LH feedforward, LH → Te feedforward, and Te → GnRH/LH feedback. The analytical formalism should be generalizable to other ensemble regulatory systems, such as those that control growth, reproduction, stress adaptations, and glucose metabolism.
Downregulation of claudin-2 expression in renal epithelial cells by metabolic acidosis
Authors: Balkovetz Daniel F. , Chumley Phillip , Amlal Hassane
Published: July 2009

Chronic metabolic acidosis (CMA) is associated with an inhibition of fluid reabsorption in the renal proximal tubule. The effects of CMA on paracellular transport across the renal epithelial tight junction (TJ) is unknown. Claudin-2 is a transmembrane TJ-associated protein which confers TJ paracellular permeability to Na+. We examined the effects of CMA on the expression of TJ transport proteins using both in vivo and in vitro models of CMA. The results showed downregulation of claudin-2 mRNA and protein expression in the cortex of rats subjected to the NH4Cl loading model of CMA. Madin-Darby canine kidney (MDCK) and HK-2 cells are models of renal epithelial cells and express claudin-2 protein in their TJ. We examined the effects of acidic pH exposure on the expression of claudin-2 in MDCK and HK-2 renal epithelial cells. Exposure of MDCK cells to pH 6.96 medium caused a significant and reversible decrease in claudin-2 protein abundance. A dose-response analysis of acidic medium exposure of MDCK and HK-2 cells demonstrated a downregulation of claudin-2 protein. The downregulation effect of acidic pH is specific to claudin-2 expression as the expression of other TJ-associated proteins (i.e., claudin-1, -3, -4, and -7, occludin, and zonula occludens-1) remained unchanged compared with control pH (7.40). Collectively, these data demonstrate that CMA downregulates the expression of claudin-2 likely through a direct effect of acidic pH. Potential physiological significance of these changes is discussed.
Low pH stimulates vasopressin V2 receptor promoter activity and enhances downregulation induced by V1a receptor stimulation
Authors: Memetimin Hasiyet , Izumi Yuichiro , Nakayama Yushi , Kohda Yukimasa , Inoue Hideki , Nonoguchi Hiroshi , Tomita Kimio
Published: July 2009

Arginine vasopressin (AVP) plays a key role in the urine concentration mechanism via the vasopressin V2 receptor (V2R) and aquaporin 2 (AQP2) in the kidney. It is well known that V2R is localized on the basolateral side and the V1a receptor (V1aR) is distributed on the luminal side of the collecting ducts. Previously, we reported an increase of V1aR mRNA and a decrease of V2R mRNA in the collecting ducts under chronic metabolic acidosis. However, the regulatory mechanism of V2R in acidic conditions has not yet been determined. In the present study, we investigated the effect of changes in pH on V2R promoter activity, using the LLC-PK1cell line stably expressing rat V1aR (LLC-PK1/rV1aR). The rV2R promoter activity was significantly increased at 12 h after the incubation in low-pH conditions, which was sustained for 24 h. mRNA and protein expressions of V2R were also increased in low-pH conditions. V1aR stimulation suppressed rV2R promoter activity in a pH-dependent manner. PKA and JNK inhibitors suppressed rV2R promoter activity in both neutral and low-pH conditions without FBS. However, a JNK inhibitor prevented the increase of V2R promoter activity only in low-pH conditions in the presence of FBS. In summary, V2R expression is increased at transcriptional, mRNA, and protein levels in LLC-PK1/rV1aR cells under low-pH conditions. Acidic condition-induced V2R enhancement was suppressed by V1aR stimulation, suggesting the crucial role of V1aR in water and electrolyte homeostasis in acidosis.
Supine and prone differences in regional lung density and pleural pressure gradients in the human lung with constant shape
Authors: Tawhai Merryn H. , Nash Martyn P. , Lin Ching-Long , Hoffman Eric A.
Published: July 2009

The explanation for prone and supine differences in tissue density and pleural pressure gradients in the healthy lung has been inferred from several studies as compression of dependent tissue by the heart in the supine posture; however, this hypothesis has not been directly confirmed. Differences could also arise from change in shape of the chest wall and diaphragm, and because of shape with respect to gravity. The contribution of this third mechanism is explored here. Tissue density and static elastic recoil were estimated in the supine and prone left human lung at functional residual capacity using a finite-element analysis. Supine model geometries were derived from multidetector row computed tomography imaging of two subjects: one normal ( subject 1), and one with small airway disease ( subject 2). For each subject, the prone model was the supine lung shape with gravity reversed; therefore, the prone model was isolated from the influence of displacement of the diaphragm, chest wall, or heart. Model estimates were validated against multidetector row computed tomography measurement of regional density for each subject supine and an independent study of the prone and supine lung. The magnitude of the gradient in density supine (−4.33%/cm for subject 1, and −4.96%/cm for subject 2) was nearly twice as large as for the prone lung (−2.72%/cm for subject 1, and −2.51%/cm for subject 2), consistent with measurements in dogs. The corresponding pleural pressure gradients were 0.54 cmH2O/cm ( subject 1) and 0.56 cmH2O/cm ( subject 2) for supine, and 0.29 cmH2O/cm ( subject 1) and 0.27 cmH2O/cm ( subject 2) for prone. A smaller prone gradient was predicted without shape change of the “container” or support of the heart by the lung. The influence of the heart was to constrain the shape in which the lung deformed.
Neural Correlates of Novel Object and Novel Location Recognition Behavior in the Mouse Anterior Cingulate Cortex
Authors: Weible Aldis P. , Rowland David C. , Pang Raina , Kentros Clifford
Published: July 2009

The anterior cingulate cortex (ACC) is a component of the limbic system implicated in a wide variety of functions spanning motor and sensory information processing, memory, attention, novelty detection, and comparisons of expectation versus outcome. It remains unclear how much of this functional diversity stems from differences in methodology or interpretation versus truly reflecting the range of processes in which the ACC is involved. In the present study, ACC neuronal activity was examined in freely behaving mice (C57BL6/J) under conditions allowing investigation of many of the cited functions in conditions free from externally applied rules: tests of novel object and novel location recognition memory. Behavioral activity and neuronal activity were recorded first in the open field, during the initial exposure and subsequent familiarization to two identical objects, and finally during the recognition memory tests. No discernible stable firing correlates of ACC neurons were found in the open field, but the addition of objects led to lasting changes in the firing patterns of many ACC neurons around one or both of the object locations. During the novel location test, some neurons followed the familiar object to its new location, others fired exclusively where the object had been, and yet others fired to both current and former object locations. Many of these same features were observed during tests of object recognition memory. However, the magnitude of the neuronal preference for the novel or the familiar object was markedly greater than that observed during either the tests of location recognition or novel object preferences in animals that did not exhibit the expected behavior. The present study reveals, for the first time, single-neuron correlates of object and location recognition behaviors in the rodent ACC and suggests that neurons of the ACC provide a distributed representation of all of the salient features of a task.
Permanence and Global Stability of Positive Periodic Solutions of a Discrete Competitive System
Authors: Qin Wenjie , Liu Zhijun , Chen Yiping
Published: July 2009

We consider the dynamic behaviors of a discrete
competitive system. A good understanding of the permanence, existence,
and global stability of positive periodic solutions is gained. Numerical
simulations are also presented to substantiate the analytical results.
Responses to Online GSTM1 Genetic Test Results among Smokers Related to Patients with Lung Cancer: A Pilot Study
Authors: Sanderson Saskia C. , O'Neill Suzanne C. , White Della Brown , Bepler Gerold , Bastian Lori , Lipkus Isaac M. , McBride Colleen M.
Published: July 2009

Providing smokers with personal genetic test results indicating increased lung cancer risk may increase uptake of effective smoking cessation services. Using the internet may increase reach and enable real-time assessment of how people process genetic risk information away from the clinic setting. We therefore explored smokers' responses to Web-delivered GSTM1 genetic test results indicating higher or lower lung cancer risk. Participants were smokers (n = 44) biologically related to patients with newly diagnosed lung cancer. Measures were assessed at baseline, before and immediately after receipt of online genetic test results, and at 6-month follow-up. Outcomes included accurate comprehension of results, regret about being tested, cessation-related cognitions (e.g., perceived response efficacy), and uptake of free smoking cessation services (nicotine replacement therapy, printed self-help materials, telephone counseling sessions). Twenty-two “relative smokers” received a GSTM1-missing (higher risk) and 22 a GSTM1-present (lower risk) result. All relative smokers with GSTM1-missing results and 55% of those with GSTM1-present results accurately interpreted their results. No relative smokers regretted having taken the test. Relative smokers receiving GSTM1-missing results reported lower confidence that quitting could reduce lung cancer risk (perceived response efficacy) than those receiving GSTM1-present results. There were no other significant between-group differences. Uptake of smoking cessation services was high (e.g., 91% nicotine replacement therapy uptake). Genetic test results may not influence uptake of free smoking cessation services because of ceiling effects. Further research is needed to determine the risks and benefits of Web-based disclosure of genetic test results. (Cancer Epidemiol Biomarkers Prev 2009;18(7):1953–61)
Meat and Heterocyclic Amine Intake, Smoking, NAT1 and NAT2 Polymorphisms, and Colorectal Cancer Risk in the Multiethnic Cohort Study
Authors: Nöthlings Ute , Yamamoto Jennifer F. , Wilkens Lynne R. , Murphy Suzanne P. , Park Song-Yi , Henderson Brian E. , Kolonel Laurence N. , Le Marchand Loïc
Published: July 2009

Background: N-acetyltransferases (NAT) 1 and 2 are polymorphic enzymes catalyzing the metabolic activation of heterocyclic amines. We investigated the modifying effects of NAT1 and NAT2 polymorphisms on the association of meat consumption, heterocyclic amine intake, and smoking with colorectal cancer risk.

Method: In the Multiethnic Cohort study, participants completed a smoking history and a food-frequency questionnaire at recruitment and a cooked meat module 5 years later to estimate heterocyclic amine intake (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline). Blood samples were collected from incident cases and age-, sex-, ethnicity-, frequency-matched controls to determine genotypes. For analysis of meat intake and smoking, data were available for 1,009 cases and 1,522 controls; for heterocyclic amine intake analyses, 398 cases and 1,444 controls were available. Multivariate logistic regression models were used to estimate odds ratios.

Results: Smoking was associated with an increased colorectal cancer risk (odds ratio, 1.51; 95% confidence interval, 1.17-1.95) for ≥30 pack-years compared with never smokers (P trend = 0.0004). The association was stronger with presence of the “rapid” compared with the “slow/intermediate” NAT2 genotype (P interaction = 0.003). No significant associations were observed for intakes of red meat, processed meat, and heterocyclic amine, or meat doneness preference, but a dietary pattern high in meat showed a weak positive interaction with the NAT2 genotype (P interaction = 0.05).

Conclusion: The enhanced association between smoking and colorectal cancer risk in subjects with the NAT2 rapid genotype supports a role for NAT2 and tobacco smoke heterocyclic amines in the etiology of colorectal cancer. This study only provides weak support for a similar association with meat heterocyclic amines. (Cancer Epidemiol Biomarkers Prev 2009;18(7):2098–106)
Association of Plasma Micronutrient Levels and Urinary Isoprostane with Risk of Lung Cancer: The Multiethnic Cohort Study
Authors: Epplein Meira , Franke Adrian A. , Cooney Robert V. , Morris J. Steven , Wilkens Lynne R. , Goodman Marc T. , Murphy Suzanne P. , Henderson Brian E. , Kolonel Laurence N. , Le Marchand Loïc
Published: July 2009

Although smoking is the primary risk factor for lung cancer, there is evidence to suggest that fruit and vegetable intake are important cofactors. The present case-control study, nested within the Multiethnic Cohort Study, examined the associations of biomarkers of fruit and vegetable intake (individual plasma micronutrient levels), serum selenium, and a urinary biomarker for total lipid peroxidation with lung cancer risk. Two hundred seven incident cases were matched to 414 controls on age, sex, ethnicity, study location (Hawaii or California), smoking status, date/time of collection, and hours of fasting. We measured prediagnositic circulating levels of individual tocopherols and carotenoids, retinol, and serum selenium, and urinary 15-isoprostane F2t. Conditional logistic regression was used to compute odds ratios (OR) and 95% confidence intervals (CI). For men, strong reductions in risk were seen with increasing tertiles of each plasma carotenoid, with the ORs for the third tertile, compared with the first tertile, ranging from 0.24 to 0.45 (Ptrends, 0.002-0.04). No associations were found among women for carotenoids or among either sex for tocopherols, selenium, and retinol. A doubling in risk was seen for men in the second and third tertiles, compared with the first tertile of urinary 15-isoprostane F2t (OR, 2.31; 95% CI, 1.02-5.25; and OR, 2.16; 95% CI, 0.98-4.78). This study supports the previously observed association between circulating carotenoids and lung cancer risk in men, and adds to the limited literature regarding urinary 15-isoprostane F2t as a marker of cancer risk. Future research examining the possible relationship between isoprostanes and lung cancer is warranted. (Cancer Epidemiol Biomarkers Prev 2009;18(7):1962–70)
Differences in Measured Mammographic Density in the Menstrual Cycle
Authors: Hovhannisyan Gayane , Chow Lorraine , Schlosser Alexandra , Yaffe Martin J. , Boyd Norman F. , Martin Lisa J.
Published: July 2009

Background: In premenopausal women, the sensitivity of screening mammography for detecting breast cancer has been reported to be greater in the follicular phase than in the luteal phase of the menstrual cycle, which may be due to differences in mammographic density. To examine this possible effect, we compared mammographic density in premenopausal women who had mammograms at different phases of the menstrual cycle.

Methods: We recruited premenopausal women ages 40 to 49 years from two mammography units in Toronto, recorded the first day of the last menstrual period (LMP) and measured mammographic density using Cumulus software. We classified the time of the mammography examination as having occurred in one of four intervals, 1 (first week after LMP), 2 (second week after LMP), 3 (third week after LMP) and 4 (>3 weeks after LMP), and compared mammographic density across intervals.

Results: Of the 936 women included in the analysis, 620 were examined by film and 316 by digital mammography. There were small and statistically nonsignificant variations in breast dense, nondense area, and percent density over the menstrual cycle in women examined by film mammography. Marginally significant variation in percent density was observed in the digital subset due to significant differences in the amount of nondense tissue over the menstrual cycle.

Conclusion: Variations in mammographic density over the menstrual cycle were small and nonsignificant for women examined by either film or digital mammography. Thus, timing of mammography in menstrual cycle is unlikely to have a significant influence in breast cancer detection by screening mammography. (Cancer Epidemiol Biomarkers Prev 2009;18(7):1993–9)
Influence of Reproductive Factors on Mortality after Epithelial Ovarian Cancer Diagnosis
Authors: Robbins Cheryl L. , Whiteman Maura K. , Hillis Susan D. , Curtis Kathryn M. , McDonald Jill A. , Wingo Phyllis A. , Kulkarni Aniket , Marchbanks Polly A.
Published: July 2009

Introduction: Although many studies have examined the influence of reproductive factors on ovarian cancer risk, few have investigated their effect on ovarian cancer survival. We examined the prognostic influence of reproductive factors on survival after ovarian cancer diagnosis.

Methods: We conducted a longitudinal analysis of 410women, ages 20 to 54 years, who participated in the 1980 to 1982 Cancer and Steroid Hormone study as incident ovarian cancer cases. We obtained their vital status by linking Cancer and Steroid Hormone records with Surveillance, Epidemiology, and End Results data. We used the Kaplan-Meier approach to estimate survival probabilities and Cox proportional hazards models to estimate hazard ratios (HR) and 95% confidence intervals (95% CI).

Results: During a median follow-up of 9.2 years, 212women died. Of the reproductive factors examined, only age at menarche and number of lifetime ovulatory cycles (LOC) relative to age significantly predicted ovarian cancer survival. Risk for death was higher among women with highest number of LOC compared with those having fewest LOC (HR, 1.67; 95% CI, 1.20-2.33). Women with fewest LOC had the highest 15-year survival (56.7%; 95% CI, 47.8-64.6%), and women with the highest LOC had the poorest (33.3%; 95% CI, 25.3-41.5%). Women whose age at menarche was <12 years had a higher risk of death compared with women whose menses began at ≥14 years (HR, 1.51; 95% CI, 1.02-2.24).

Conclusions: We found that high LOC and early age at menarche were associated with decreased survival after ovarian cancer. (Cancer Epidemiol Biomarkers Prev 2009;18(7):2035–41)
Latinas and Breast Cancer Outcomes: Population-Based Sampling, Ethnic Identity, and Acculturation Assessment
Authors: Hamilton Ann S. , Hofer Timothy P. , Hawley Sarah T. , Morrell Donna , Leventhal Meryl , Deapen Dennis , Salem Barbara , Katz Steven J.
Published: July 2009

Purpose: Latinas and African-Americans with breast cancer, especially those of lower socioeconomic status and acculturation, have been underrepresented in studies assessing treatment satisfaction, decision-making, and quality of life. A study was designed to recruit a large and representative sample of these subgroups.

Materials and Methods: Incident cases were selected by rapid case ascertainment (RCA) in the Los Angeles Surveillance, Epidemiology, and End Results Registry from 2005 to 2006, with oversampling of Latinas and African-Americans. Patients were mailed a questionnaire and $10 incentive 5 to 6 months after diagnosis; nonrespondents were contacted by telephone. Multivariate analysis was used to assess possible response bias. The RCA definition of Hispanic origin was validated by self-reports. The Short Acculturation Scale for Hispanics index for Latina respondents was used.

Results: One thousand six hundred and ninety-eight eligible breast cancer cases were selected and 1,223 participated, for a response rate of 72.0%, which varied little by race/ethnicity. Age, race/ethnicity, and clinical factors were not associated with response; however, respondents were slightly more likely to be married and from higher socioeconomic status census tracts than nonrespondents. The RCA definition of Hispanic identity was highly sensitive (94.6%) and specific (90.0%). Lower acculturation was associated with lower education and literacy among Latinas.

Discussion: High response rates among all subgroups were achieved due to the use of RCA, an incentive, extensive telephone follow-up, a native Spanish-speaking interviewer, and a focused questionnaire. The low acculturation index category identified a highly vulnerable subgroup. This large sample representing subgroups with greater problems will provide a basis for developing better interventions to assist these women. (Cancer Epidemiol Biomarkers Prev 2009;18(7):2022–9)
Anthropometry and Esophageal Cancer Risk in the European Prospective Investigation into Cancer and Nutrition
Authors: Steffen Annika , Schulze Matthias B. , Pischon Tobias , Dietrich Thomas , Molina Esther , Chirlaque Maria-Dolores , Barricarte Aurelio , Amiano Pilar , Quirós J. Ramón , Tumino Rosario , Mattiello Amalia , Palli Domenico , Vineis Paolo , Agnoli Claudia , Misirli Gesthimani , Boffetta Paolo , Kaaks Rudolf , Rohrmann Sabine , Bueno-de-Mesquita H. Bas , Peeters Petra H.M. , May Anne M. , Spencer Elizabeth A. , Allen Naomi E. , Bingham Sheila , Tjønneland Anne , Halkjær Jytte , Overvad Kim , Stegger Jakob , Manjer Jonas , Lindkvist Björn , Hallmanns Göran , Stenling Roger , Lund Eiliv , Riboli Elio , Gonzalez Carlos A. , Boeing Heiner
Published: July 2009

Background: Increasing evidence suggests that general obesity [measured by body mass index (BMI)] is positively associated with risk of esophageal adenocarcinoma (EAC). In contrast, previous studies have shown inverse relations with esophageal squamous cell carcinoma (ESCC). However, it is still unclear whether body fat distribution, particularly abdominal obesity, is associated with each type of esophageal cancer.

Methods: We applied multivariable adjusted Cox proportional hazards regression to investigate the association between anthropometric measures and risk of EAC and ESCC among 346,554 men and women participating in the European Prospective Investigation into Cancer and Nutrition. All statistical tests were two sided.

Results: During 8.9 years of follow-up, we documented 88 incident cases of EAC and 110 cases of ESCC. BMI, waist circumference, and waist-to-hip ratio (WHR) were positively associated with EAC risk [highest versus lowest quintile; relative risk (RR), 2.60; 95% confidence interval (95% CI), 1.23-5.51; Ptrend < 0.01; RR, 3.07; 95% CI, 1.35-6.98; Ptrend < 0.003; and RR, 2.12; 95% CI, 0.98-4.57; Ptrend < 0.004]. In contrast, BMI and waist circumference were inversely related to ESCC risk, whereas WHR showed no association with ESCC. In stratified analyses, BMI and waist circumference were significantly inversely related to ESCC only among smokers but not among nonsmokers. However, when controlled for BMI, we found positive associations for waist circumference and WHR with ESCC, and these associations were observed among smokers and nonsmokers.

Conclusion: General and abdominal obesity were associated with higher EAC risk. Further, our study suggests that particularly an abdominal body fat distribution might also be a risk factor for ESCC. (Cancer Epidemiol Biomarkers Prev 2009;18(7):2079–89)
Noninvasive Quantification of Systemic-to-Pulmonary Collateral Flow
Authors: Whitehead Kevin K. , Gillespie Matthew J. , Harris Matthew A. , Fogel Mark A. , Rome Jonathan J.
Published: July 2009

Background—

Systemic-to-pulmonary collateral flow (SPCF) is common in single-ventricle patients with superior cavopulmonary connections (SCPC). Because no validated method to quantify SPCF exists, neither its hemodynamic burden nor its clinical impact can be systematically evaluated. We hypothesize that (1) the difference in total ascending aortic (Ao) and caval flow (superior vena cava [SVC]+inferior vena cava [IVC]) and (2) the difference between pulmonary vein and pulmonary artery flow (PV−PA) provide 2 independent estimators of SPCF.

Methods and Results—

We measured Ao, SVC, IVC, right (RPA) and left (LPA) PA, and left (LPV) and right (RPV) PV flows in 17 patients with SCPC during routine cardiac MRI studies using through-plane phase-contrast velocity mapping. Two independent measures of SPCF were obtained: model 1, Ao−(SVC+IVC); and model 2, (LPV−LPA)+(RPV−RPA). Values were normalized to body surface area, Ao, and PV, and comparisons were made using linear regression and Bland-Altman analysis. SPCF ranged from 0.2 to 1.4 L/min for model 1 and 0.2 to 1.6 L/min for model 2, for an average indexed SPCF of 0.5 to 2.8 L/min/m
2
: 11% to 53% (mean, 37%) of Ao and 19% to 77% (mean, 54%) of PV. The mean difference between model 1 and model 2 was 0.01 L/min (
P
=0.40; 2-SD range, −0.45 to 0.47 L/min).

Conclusions—

We present a noninvasive method for SPCF quantification in patients with SCPC. It should provide an important clinical tool in treating these patients. Furthermore, we show that SPCF is a significant hemodynamic burden in many patients with bidirectional Glenn shunt physiology. Future investigations will allow objective study of the impact of collateral flow on outcome.
Validation of Solar Radiation Surfaces from MODIS and Reanalysis Data over Topographically Complex Terrain
Authors: Schroeder Todd A. , Hember Robbie , Coops Nicholas C. , Liang Shunlin
Published: July 2009

The magnitude and distribution of incoming shortwave solar radiation (SW↓) has significant influence on the productive capacity of forest vegetation. Models that estimate forest productivity require accurate and spatially explicit radiation surfaces that resolve both long- and short-term temporal climatic patterns and that account for topographic variability of the land surface. This paper presents a validation of monthly average total (SW↓t) and diffuse ( SW↓df ) incoming solar radiation surfaces taken from North American Regional Reanalysis (NARR) data and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery for a mountainous region of the Pacific northwestern United States and Canada. A topographic solar radiation model based on a regionally defined clearness index was used to downscale the 32-km NARR SW↓t surfaces to 1 km, resulting in surfaces that better matched the spatial resolution of MODIS, as well as accounted for elevation and terrain effects including shadowing. Validation was carried out using a series of ground station measurements (n = 304) collected in 2003. The results indicated that annually, the NARR and MODIS SW↓t surfaces were both in strong agreement with ground measurements (r = 0.98 and 0.97), although the strength and bias of the relationships varied considerably by month. Correlations were highest in winter, early summer, and fall and lowest in spring. The NARR and MODIS SW↓df surfaces displayed poorer agreement with ground measurements (r = 0.89 and 0.79), the result of some months having negative correlations. The correlation and spatial structure between NARR and MODIS SW↓t surfaces was enhanced by topographic correction, resulting in more consistent input radiation surfaces for use in broad-scale forest productivity modeling.
Precipitation Simulations Using WRF as a Nested Regional Climate Model
Authors: Bukovsky Melissa S. , Karoly David J.
Published: July 2009

This note examines the sensitivity of simulated U.S. warm-season precipitation in the Weather Research and Forecasting model (WRF), used as a nested regional climate model, to variations in model setup. Numerous options have been tested and a few of the more interesting and unexpected sensitivities are documented here. Specifically, the impacts of changes in convective and land surface parameterizations, nest feedbacks, sea surface temperature, and WRF version on mean precipitation are evaluated in 4-month-long simulations. Running the model over an entire season has brought to light some issues that are not otherwise apparent in shorter, weather forecast–type simulations, emphasizing the need for careful scrutiny of output from any model simulation. After substantial testing, a reasonable model setup was found that produced a definite improvement in the climatological characteristics of precipitation over that from the National Centers for Environmental Prediction–National Center for Atmospheric Research global reanalysis, the dataset used for WRF initial and boundary conditions in this analysis.
Application of CALIOP Measurements to the Evaluation of Cloud Phase Derived from MODIS Infrared Channels
Authors: Cho Hyoun-Myoung , Nasiri Shaima L. , Yang Ping
Published: July 2009

In this study, Moderate Resolution Imaging Spectroradiometer (MODIS) infrared-based cloud thermodynamic phase retrievals are evaluated using Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) retrievals for the 6 months from January to June of 2008. The CALIOP 5-km cloud-layer product provides information on cloud opacity, cloud-top height, midlayer cloud temperature, and cloud thermodynamic phase. Comparisons are made between MODIS IR phase and CALIOP observations for single-layer clouds (54% of the cloudy CALIOP scenes) and for the top layer of the CALIOP scenes. Both CALIOP and MODIS retrieve larger fractions of water clouds in the single-layer cases than in the top-layer cases, demonstrating that focusing on only single-layer clouds may introduce a water-cloud bias. Of the single-layer clouds, 60% are transparent and 40% are opaque (defined by the lack of a CALIOP ground return). MODIS tends to classify single-layer clouds with midlayer temperatures below −40°C as ice; around −30°C nearly equally as ice, mixed, and unknown; between −28° and −15°C as mixed; and above 0°C as water. Ninety-five percent of the single-layer CALIOP clouds not detected by MODIS are transparent. Approximately ⅓ of transparent single-layer clouds with temperatures below −30°C are not detected by MODIS and close to another ⅓ are classified as ice, with the rest assigned as water, mixed, or unknown. CALIOP classes nearly all of these transparent cold clouds as ice.
Microphysics of Maritime Tropical Convective Updrafts at Temperatures from −20° to −60°
Authors: Heymsfield Andrew J. , Bansemer Aaron , Heymsfield Gerald , Fierro Alexandre O.
Published: July 2009

Anvils produced by vigorous tropical convection contribute significantly to the earth’s radiation balance, and their radiative properties depend largely on the concentrations and sizes of the ice particles that form them. These microphysical properties are determined to an important extent by the fate of supercooled droplets, with diameters from 3 to about 20 microns, lofted in the updrafts. The present study addresses the question of whether most or all of these droplets are captured by ice particles or if they remain uncollected until arriving at the −38°C level where they freeze by homogeneous nucleation, producing high concentrations of very small ice particles that can persist and dominate the albedo.

Aircraft data of ice particle and water droplet size distributions from seven field campaigns at latitudes from 25°N to 11°S are combined with a numerical model in order to examine the conditions under which significant numbers of supercooled water droplets can be lofted to the homogeneous nucleation level. Microphysical data were collected in pristine to heavily dust-laden maritime environments, isolated convective updrafts, and tropical cyclone updrafts with peak velocities reaching 25 m s−1. The cumulative horizontal distance of in-cloud sampling at temperatures of −20°C and below exceeds 50 000 km. Analysis reveals that most of the condensate in these convective updrafts is removed before reaching the −20°C level, and the total condensate continues to diminish linearly upward. The amount of condensate in small (<50 μm in diameter) droplets and ice particles, however, increases upward, suggesting new droplet activation with an appreciable radiative impact. Conditions promoting the generation of large numbers of small ice particles through homogeneous ice nucleation include high concentrations of cloud condensation nuclei (sometimes from dust), removal of most of the water substance between cloud base and the −38°C levels, and acceleration of the updrafts at mid- and upper levels such that velocities exceed 5–7 m s−1.
Modeling the Effects of Lakes and Wetlands on the Water Balance of Arctic Environments
Authors: Bowling Laura C. , Lettenmaier Dennis P.
Published: July 2009

Lakes, ponds, and wetlands are common features in many low-gradient arctic watersheds. Storage of snowmelt runoff in lakes and wetlands exerts a strong influence on both the interannual and interseasonal variability of northern rivers. This influence is often not well represented in hydrology models and the land surface schemes used in climate models. In this paper, an algorithm to represent the evaporation and storage effects of lakes and wetlands within the Variable Infiltration Capacity (VIC) macroscale hydrology model is described. The model is evaluated with respect to its ability to represent water temperatures, net radiation, ice freeze–thaw, and runoff production for a variety of high-latitude locations. It is then used to investigate the influence of surface storage on the spatial and temporal distribution of water and energy fluxes for the Kuparuk and Putuligayuk Rivers, on the Alaskan arctic coastal plain. Inclusion of the lake and wetland algorithm results in a substantial improvement of the simulated streamflow hydrographs, as measured using the monthly Nash–Sutcliffe efficiency. Simulations of runoff from the Putuligayuk watershed indicate that up to 80% of snow meltwater goes into storage each year and does not contribute to streamflow. Approximately 46% of the variance in the volume of snowmelt entering storage can be explained by the year-to-year variation in maximum snow water equivalent and the lake storage deficit from the previous summer. The simulated summer lake storage deficit is much lower than the cumulative precipitation minus lake evaporation (−47 mm, on average) as a result of simulated recharge from the surrounding uplands.
Available Potential Energy and Irreversible Mixing in the Meridional Overturning Circulation
Authors: Hughes Graham O. , Hogg Andrew Mc C. , Griffiths Ross W.
Published: July 2009

The overturning circulation of the global oceans is examined from an energetics viewpoint. A general framework for stratified turbulence is used for this purpose; first, it highlights the importance of available potential energy in facilitating the transfer of kinetic energy to the background potential energy (defined as the adiabatically rearranged state with no motion). Next, it is shown that it is the rate of transfer between different energy reservoirs that is important for the maintenance of the ocean overturning, rather than the total amount of potential or kinetic energy. A series of numerical experiments is used to assess which energy transfers are significant in the overturning circulation. In the steady state, the rate of irreversible diapycnal mixing is necessarily balanced by the production of available potential energy sourced from surface buoyancy fluxes. Thus, the external inputs of available potential energy from surface buoyancy forcing and of kinetic energy from other sources (such as surface winds and tides, and leading to turbulent mixing) are both necessary to maintain the overturning circulation.
Effect of Finite Spatial Resolution on the Turbulent Energy Spectrum Measured in the Coastal Ocean Bottom Boundary Layer
Authors: Hackett Erin E. , Luznik Luksa , Katz Joseph , Osborn Thomas R.
Published: July 2009

The effect of finite spatial resolution on the measured energy spectrum is examined via a parametric study using in situ particle image velocimetry (PIV) measurements performed in the bottom boundary layer on the Atlantic continental shelf. Two-dimensional (2D) box spatial filters of various scales are applied to the data, and these filtered distributions are used to compute 1D energy spectra in both frequency and wavenumber domains. It is found that energy levels are attenuated by more than 15% at all length scales that are smaller than 10 times the scale of the filter. Filtering both in the direction of the spectrum as well as perpendicular to it contributes to the extent of attenuation, the latter via implicit integration over all wavenumbers. At scales larger than that of the filter, Gaussian, nonlinear Butterworth, and median filters attenuate less energy than the box filter. When frequency spectra are converted using Taylor’s hypothesis, wave energy appears in wavenumber space at a location different than its true physical scale, which is much larger than the filter sizes. Consequently, wave energy is not attenuated and dominates over the turbulence through this spectral range. Because wave energy and turbulence respond differently to the filtering, modified spectral slopes at the transition between wave- and turbulence-dominated regions occur, resulting in inordinately steep spectral slopes. Finally, removal of the pressure-coherent part of the velocity signal is not sufficient to reveal the turbulence within the wave peak spectral range. Remaining energy in this range is still dominated by much larger scales.
Looking Back 10 Years After the Arbour Inquiry
Authors: Dell Colleen Anne , Fillmore Catherine J. , Kilty Jennifer M.
Published: July 2009

The decade of the 1990s can be marked as one of major dissension, conflict, and change within federal corrections for women in Canada. In this article, the authors reflect back on this period of time by examining the correctional ideologies, policies, and practices that were operating in the Canadian federal prison for women. Finding these policies and practices to be inherently gendered and punitive in nature, it is argued that punishment was at the time and continues to be the cornerstone of the regulation of women prisoners, and that it takes a specific, gendered form that relies on the deployment of traditional patriarchal conceptions of femininity. Drawing on interviews with correctional personnel and analyses of correctional policies and the Arbour Inquiry transcripts, this article reconstructs Correctional Service of Canada’s (CSC) responses to incarcerated women’s “unfeminine” behavior, specifically women’s self-harming behavior and their violence against others, as overly disciplinary. It is proposed that CSC’s ideological foundation, as well as the practices and policies that were operating both at the time of and following the incident at the Kingston Prison for Women that resulted in the Arbour Inquiry, remain deeply entrenched in an oppressive hierarchical structure of gender inequality. This structure fails to question how traditional conceptions of femininity shape policies and practices. It has also aided in the construction of a new genre of “misbehaved” women in corrections, which in turn has been used to justify the harsh regulatory treatment of federally sentenced women. Without challenging its traditional gender ideologies, CSC is unable to offer any alternatives to its punitive practices, which continue to operate.
Creating a City of the Tourist Imagination: The Case of Cape Town, `The Fairest Cape of Them All'
Authors: Bickford-Smith Vivian
Published: July 2009

Many post-industrial cities have reinvented themselves both physically and imaginatively in strikingly similar fashion. Yet a vital element of place marketing remains the attempt to advertise each city's `uniqueness'. Here the deployment of historically longstanding attractions and `brand essences' often play a central role, as this case history of one city's destination branding hopefully illustrates. It explains how different tourism sites, and thus particular tourist gazes, were constructed in Cape Town from the late 19th century onwards. One key question is why no new `Africanist' vision predominated after 1994. Answering this question is not merely a matter of understanding the nature of the city's contemporary political economy, although this is certainly important; it also requires some knowledge of past historical processes, including the historical accumulation of attractions. Place-selling experts market modern cities, but not entirely in circumstances of their own choosing. History matters, yet existing literature for South African urban tourism has focused largely on contemporary developments.
Preventable Mortality as a Predictor of Community Social Organisation: Examining Reverse Causality
Authors: Feinberg Seth
Published: July 2009

Community social organisation brings individuals together, providing opportunities for collective responses to perceived neighbourhood issues and concerns. This paper considers how rates of neighbourhood mortality influence levels of community organisation. Certain types of mortality may actually enhance, not disrupt, the level of social organisation. Because urban neighbourhoods experience dramatically different mortality rates, the paper examines whether the relationship between mortality and community social organisation varies based on the causes of death and the ages of those dying. Analyses from Chicago neighbourhoods suggest that the rate at which children die from preventable causes such as homicide, suicide and accidents results in an increased likelihood that residents join neighbourhood watch organisations and participate in actions to address community problems. The effect of youth mortality is shaped in part by dense network exchanges among residents.
Isolated Entities or Integrated Neighbourhoods? An Alternative View of the Measurement of Deprivation
Authors: Rae Alasdair
Published: July 2009

The use of area-based deprivation indices is now a firmly established means of assessing which areas ought to be the focus of government policy, with separate indices of deprivation established for each constituent part of the UK. In England, the Index of Multiple Deprivation 2004 has been widely used to support decision-making for key urban policies and in more local assessments of deprivation. Implicit in the development and use of these indicators is the notion that area matters and that it can be an important influence on a whole range of different activities. However, there is also a sense in which contemporary measures of deprivation are spatially short-sighted since they are not able to account formally for the spatial context of individual locations. This paper therefore offers an alternative approach to the measurement of local conditions by combining spatial statistical approaches with a much-used deprivation index.
Ethnic Sorting in The Netherlands
Authors: Zorlu Aslan , Latten Jan
Published: July 2009

This paper examines the residential mobility behaviour of immigrants and natives in The Netherlands using a rich administrative individual data file. The inclination to move and the choice of destination neighbourhood are estimated, correcting for the selection bias of movers. Subsequently, the role of preferences and discrimination in the mobility behaviour is implicitly derived from regression estimates. The analysis shows that the percentage of natives in the destination neighbourhood is predicted to be about 18 percentage points lower for non-Western immigrants than for natives. About 65 per cent of the differential is explained by their observable characteristics; the remaining part can largely be attributed to preferences and discrimination. No indication is found of the spatial assimilation of second-generation non-Western immigrants. On the other hand, the mobility pattern of the second-generation Western immigrants is similar to that of natives.
A Case for Cases
Authors: Abell Peter
Published: July 2009

When case studies are constructed as narratives, then causal explanation can be achieved without either comparison or generalization. Narratives provide paths of causal links on a chronology of actions or events. The links, in turn, can be studied as Bayesian inferences generating Bayesian narratives. The causal paths in a narrative have a Boolean structure.