bluuebunny/crossref_metadata_2025 huggingface dataset:
Causal Models for Investigating Complex Disease: I. A Primer
Authors: Madsen Ann M. , Hodge Susan E. , Ottman Ruth
Published: September 2011

Background/Aims: To illustrate the utility of causal models for research in genetic epidemiology and statistical genetics. Causal models are increasingly applied in risk factor epidemiology, economics, and health policy, but seldom used in statistical genetics or genetic epidemiology. Unlike the statistical models usually used in genetic epidemiology, causal models are explicitly formulated in terms of cause and effect relationships occurring at the individual level. Methods: We describe two causal models, the sufficient component cause model and the potential outcomes model, and show how key concepts in genetic epidemiology, including penetrance, phenocopies, genetic heterogeneity, etiologic heterogeneity, gene-gene interaction, and gene-environment interaction, can be framed in terms of these causal models. We also illustrate how potential outcomes models can provide insight into the potential for confounding and bias in the measurement of causal effects in genetic studies. Results: Our analysis illustrates how causal models can elucidate the relationships among underlying causal mechanisms and measures obtained from statistical analysis of observed data. Conclusion: Causal models can enhance research aimed at identifying causal genes.
Chronic Consumption of trans-Fat-Rich Diet Increases Hepatic Cholesterol Levels and Impairs Muscle Insulin Sensitivity without Leading to Hepatic Steatosis and Hypertriglyceridemia in Female Fischer Rats
Authors: Jeyakumar Shanmugam M. , Prashant Ananthathmakula , Rani Koppala Swarupa , Laxmi Rajkumar , Vani Acharya , Kumar Putcha Uday , Vajreswari Ayyalasomayajula
Published: September 2011

Background: The impact of industrial trans fatty acids (TFAs) on lipid metabolism and health remains elusive. Methods: We compared the effect of long-term (52 weeks) ingestion of 10% partially hydrogenated vegetable oil, providing 4.2% of total energy from TFAs, on hepatic lipid metabolism and muscle insulin sensitivity in weanling female Fischer rats with that of palmolein (monounsaturated fatty acid, MUFA), sunflower (n–6 polyunsaturated fatty acid, PUFA), and a blend of sunflower and fish oil (n–3 PUFA). Results: The proportion of plasma high-density lipoprotein cholesterol in total cholesterol and reverse cholesterol transport-associated protein expressions were similar in all the groups. Despite higher lipogenic-pathway protein levels, steatosis or hypertriglyceridemia was not observed in TFA-fed rats. Though TFA ingestion had no effect on fasting plasma glucose, insulin levels or oral glucose tolerance, it significantly decreased muscle insulin-stimulated glucose uptake as compared to PUFAs. Further, TFA ingestion increased adipose tissue retinol-binding protein 4 mRNA as compared to PUFAs (n–6 or n–3). The effects of MUFA (oleic acid) on all these parameters were comparable to those observed for TFAs. Conclusions: Compared to PUFA-rich diets, chronic consumption of a TFA-rich diet did not lead to steatosis or hypertriglyceridemia; however, it significantly impaired muscle insulin sensitivity, while no changes were found in the oral glucose tolerance test.
Genetic Variation in Liver X Receptor Alpha and Risk of Ischemic Vascular Disease in the General Population
Authors: Stender Stefan , Frikke-Schmidt Ruth , Anestis Aristomenis , Kardassis Dimitris , Sethi Amar A. , Nordestgaard Børge G. , Tybjærg-Hansen Anne
Published: September 2011

Objective—

Although animal studies indicate that
liver X receptor alpha
(
LXR
α) might influence risk of atherosclerosis, data in humans remain scarce. We tested the hypothesis that genetic variation in
LXR
α associates with risk of ischemic vascular disease and/or plasma lipid and lipoprotein levels in the general population.

Methods and Results—

We studied 10,281 white persons of Danish ancestry from a general population cohort, including 1,986 in whom ischemic heart disease (IHD) developed, and 989 in whom ischemic cerebrovascular disease developed. We examined another 51,429 white persons of Danish ancestry from a general population study, including 3,789 with IHD. We genotyped 10 genetic variants identified by resequencing
LXR
α. Homozygosity for −840AA/−115AA(=2.7%) predicted hazard ratios of 1.3 (95% confidence interval, 1.0–1.7) for IHD, 1.6 (1.2–2.2) for myocardial infarction, and 1.7 (1.3–2.4) for ischemic cerebrovascular disease. The corresponding odds ratios in the second cohort were 1.1 (0.9–1.4) for IHD and 1.5 (1.1–2.0) for myocardial infarction. In the combined studies, odds ratios were 1.2 (1.0–1.4) for IHD and 1.5 (1.2–1.9) for myocardial infarction. Homozygosity for −840AA/−115AA did not associate with lipid or lipoprotein levels.
LXR
α −1830T>C (tagging the haplotype −1830C/−840A/−115A, all r
2
≥0.97) associated with 91% increased transcriptional activity.

Conclusion—

This study suggests that functional genetic variation in
LXR
α predicts risk of ischemic vascular disease in the general population.
Plasma Lipidomic Analysis of Stable and Unstable Coronary Artery Disease
Authors: Meikle Peter J. , Wong Gerard , Tsorotes Despina , Barlow Christopher K. , Weir Jacquelyn M. , Christopher Michael J. , MacIntosh Gemma L. , Goudey Benjamin , Stern Linda , Kowalczyk Adam , Haviv Izhak , White Anthony J. , Dart Anthony M. , Duffy Stephen J. , Jennings Garry L. , Kingwell Bronwyn A.
Published: September 2011

Objective—

Traditional risk factors for coronary artery disease (CAD) fail to adequately distinguish patients who have atherosclerotic plaques susceptible to instability from those who have more benign forms. Using plasma lipid profiling, this study aimed to provide insight into disease pathogenesis and evaluate the potential of lipid profiles to assess risk of future plaque instability.

Methods and Results—

Plasma lipid profiles containing 305 lipids were measured on 220 individuals (matched healthy controls, n=80; stable angina, n=60; unstable coronary syndrome, n=80) using electrospray-ionisation tandem mass spectrometry. ReliefF feature selection coupled with an L2-regularized logistic regression based classifier was used to create multivariate classification models which were verified via 3-fold cross-validation (1000 repeats). Models incorporating both lipids and traditional risk factors provided improved classification of unstable CAD from stable CAD (C-statistic=0.875, 95% CI 0.874–0.877) compared with models containing only traditional risk factors (C-statistic=0.796, 95% CI 0.795–0.798). Many of the lipids identified as discriminatory for unstable CAD displayed an association with disease acuity (severity), suggesting that they are antecedents to the onset of acute coronary syndrome.

Conclusion—

Plasma lipid profiling may contribute to a new approach to risk stratification for unstable CAD.
Role for Circulating Osteogenic Precursor Cells in Aortic Valvular Disease
Authors: Egan Kevin P. , Kim Jung-Hoon , Mohler Emile R. , Pignolo Robert J.
Published: September 2011

Objective—

Approximately 13% of aortic valves removed from patients with end-stage aortic valve disease contain heterotopic ossification (HO). Recently, we identified a novel population of circulating osteogenic precursor (COP) cells that are derived from bone marrow and have the capability to form bone. These cells are identified by coexpression of the osteogenic marker type 1 collagen or osteoclacin and the hematopoietic marker CD45. We tested the hypothesis that these cells may contribute to heart valve stenosis.

Methods and Results—

Quantification of CD45
+
osteoclacin
+
COP cells by flow cytometry showed that they represent up to 1.1% of mononuclear cells. Clonally derived COP cells produce bone morphogenetic proteins 2 and 4 by immunohistochemical analysis. We reviewed 105 cases of end-stage aortic valvular disease and confirmed HO in 13 archived specimens. Using immunohistochemistry, we identified COP cells by coexpression of CD45 and type 1 collagen. There was a statistically significant association between the presence of COP cells and early HO lesions. COP cells were negligible in regions of unaffected valve leaflets (no HO) from the same individuals.

Conclusion—

This study provides the first evidence that osteogenic cells in the blood home to sites of vascular injury and are associated with HO formation in heart valves.
Nucleotide-Binding Oligomerization Domain Protein 2 Deficiency Enhances Neointimal Formation in Response to Vascular Injury
Authors: Kwon Min-Young , Liu Xiaoli , Lee Seon-Jin , Kang Young-Ho , Choi Augustine M.K. , Lee Ki-Up , Perrella Mark A. , Chung Su Wol
Published: September 2011

Objective—

Nucleotide-binding oligomerization domain protein 2 (NOD2) stimulates diverse inflammatory responses resulting in differential cellular phenotypes. To identify the role of NOD2 in vascular arterial obstructive diseases, we investigated the expression and pathophysiological role of NOD2 in a vascular injury model of neointimal hyperplasia.

Methods and Results—

We first analyzed for neointimal hyperplasia following femoral artery injury in NOD2
+/+
and NOD2
−/−
mice. NOD2
−/−
mice showed a 2.86-fold increase in neointimal formation that was mainly composed of smooth muscle (SM) α-actin positive cells. NOD2 was expressed in vascular smooth muscle cells (VSMCs) and NOD2
−/−
VSMCs showed increased cell proliferation in response to mitogenic stimuli, platelet-derived growth factor-BB (PDGF-BB), or fetal bovine serum, compared with NOD2
+/+
VSMCs. Furthermore, NOD2 deficiency markedly promoted VSMCs migration in response to PDGF-BB, and this increased cell migration was attenuated by a phosphatidylinositol 3-kinase inhibitor. However, protein kinase C and c-Jun N-terminal kinase inhibitors exerted negligible effects. Moreover, muramyl dipeptide–stimulated NOD2 prevented PDGF-BB-induced VSMCs migration.

Conclusion—

Functional NOD2 was found to be expressed in VSMCs, and NOD2 deficiency promoted VSMCs proliferation, migration, and neointimal formation after vascular injury. These results provide evidence for the involvement of NOD2 in vascular homeostasis and tissue injury, serving as a potential molecular target in the modulation of arteriosclerotic vascular disease.
Prognostic Importance of Early Worsening Renal Function After Initiation of Angiotensin-Converting Enzyme Inhibitor Therapy in Patients With Cardiac Dysfunction
Authors: Testani Jeffrey M. , Kimmel Stephen E. , Dries Daniel L. , Coca Steven G.
Published: September 2011

Background—

Worsening renal function (WRF) in the setting of heart failure has been associated with increased mortality. However, it is unclear if this decreased survival is a direct result of the reduction in glomerular filtration rate (GFR) or if the mechanism underlying the deterioration in GFR is driving prognosis. Given that WRF in the setting of angiotensin-converting enzyme inhibitor (ACE-I) initiation is likely mechanistically distinct from spontaneously occurring WRF, we investigated the relative early WRF-associated mortality rates in subjects randomized to ACE-I or placebo.

Methods and Results—

Subjects in the Studies Of Left Ventricular Dysfunction (SOLVD) limited data set (n=6337) were studied. The interaction between early WRF (decrease in estimated GFR ≥20% at 14 days), randomization to enalapril, and mortality was the primary end point. In the overall population, early WRF was associated with increased mortality (adjusted hazard ratio [HR], 1.2; 95% CI, 1.0–1.4;
P
=0.037). When analysis was restricted to the placebo group, this association strengthened (adjusted HR, 1.4; 95% CI, 1.1–1.8;
P
=0.004). However, in the enalapril group, early WRF had no adverse prognostic significance (adjusted HR, 1.0; 95% CI, 0.8–1.3;
P
=1.0;
P
=0.09 for the interaction). In patients who continued to receive study drug despite early WRF, a survival advantage remained with enalapril therapy (adjusted HR, 0.66; 95% CI, 0.5–0.9;
P
=0.018).

Conclusions—

These data support the notion that the mechanism underlying WRF is important in determining its prognostic significance. Specifically, early WRF in the setting of ACE-I initiation appears to represent a benign event that is not associated with a loss of benefit from continued ACE-I therapy.
Differential Protein Kinase C Isoform Regulation and Increased Constitutive Activity of Acetylcholine-Regulated Potassium Channels in Atrial Remodeling
Authors: Makary Samy , Voigt Niels , Maguy Ange , Wakili Reza , Nishida Kunihiro , Harada Masahide , Dobrev Dobromir , Nattel Stanley
Published: September 2011

Rationale:

Atrial fibrillation (AF) causes atrial-tachycardia remodeling (ATR), with enhanced constitutive acetylcholine-regulated K
+
current (I
KAChC
) contributing to action potential duration shortening and AF promotion. The underlying mechanisms are unknown.

Objective:

To evaluate the role of protein-kinase C (PKC) isoforms in ATR-induced I
KAChC
activation.

Methods and Results:

Cells from ATR-dogs (400-bpm atrial pacing for 1 week) were compared to control dog cells. In vitro tachypaced (TP; 3 Hz) canine atrial cardiomyocytes were compared to parallel 1-Hz paced cells. I
KAChC
single-channel activity was assessed in cell-attached and cell-free (inside-out) patches. Protein expression was assessed by immunoblot. In vitro TP activated I
KAChC
, mimicking effects of in vivo ATR. Discrepant effects of PKC activation and inhibition between control and ATR cells suggested isoform-selective effects and altered PKC isoform distribution. Conventional PKC isoforms (cPKC; including PKCα) inhibited, whereas novel isoforms (including PKCε) enhanced, acetylcholine-regulated K
+
current (I
KACh
) in inside-out patches. TP and ATR downregulated PKCα (by 33% and 37%, respectively) and caused membrane translocation of PKCε, switching PKC predominance to the stimulatory novel isoform. TP increased [Ca
2+
]
i
at 2 hours by 30%, with return to baseline at 24 hours. Buffering [Ca
2+
]
i
during TP with the cell-permeable Ca
2+
chelator BAPTA-AM (1 μmol/L) or inhibiting the Ca
2+
-dependent protease calpain with PD150606 (20 μmol/L) prevented PKCα downregulation and TP enhancement of I
KAChC
. PKCε inhibition with a cell-permeable peptide inhibitor suppressed TP/ATR-induced I
KAChC
activation, whereas cPKC inhibition enhanced I
KAChC
activity in 1-Hz cells.

Conclusions:

PKC isoforms differentially modulate I
KACh
, with conventional Ca
2+
-dependent isoforms inhibiting and novel isoforms enhancing activity. ATR causes a rate-dependent PKC isoform switch, with Ca
2+
/calpain-dependent downregulation of inhibitory PKCα and membrane translocation of stimulatory PKCε, enhancing I
KAChC
. These findings provide novel insights into mechanisms underlying I
KAChC
dysregulation in AF.
Outcomes in Mild or Rapidly Improving Stroke Not Treated With Intravenous Recombinant Tissue-Type Plasminogen Activator
Authors: Smith Eric E. , Fonarow Gregg C. , Reeves Mathew J. , Cox Margueritte , Olson DaiWai M. , Hernandez Adrian F. , Schwamm Lee H.
Published: September 2011

Background and Purpose—

Mild or rapidly improving stroke is a frequently cited reason for not giving intravenous recombinant tissue-type plasminogen activator (rtPA), but some of these patients may have poor outcomes. We used data from a large nationwide study (Get With The Guidelines–Stroke) to determine risk factors for poor outcomes after mild or improving stroke at hospital discharge.

Methods—

Between 2003 and 2009, there were 29 200 ischemic stroke patients (from 1092 hospitals) arriving within 2 hours after symptom onset with mild or rapidly improving stroke symptoms as the only contraindication to rtPA. Logistic regression was used to determine the independent predictors of discharge to home.

Results—

Among 93 517 patients arriving within 2 hours, 31.2% (29 200) did not receive rtPA solely because of mild/improving stroke. Among the 29 200 mild/improving cases, 28.3% were not discharged to home, and 28.5% were unable to ambulate without assistance at hospital discharge. The likelihood of home discharge was strongly related to initial National Institutes of Health Stroke Scale score (
P
<0.001). In multivariable-adjusted analysis, patients not discharged to home were more likely to be older, female, and black; have a higher National Institutes of Health Stroke Scale score and vascular risk factors; and were less likely to be taking lipid-lowering medication before admission.

Conclusions—

In this large, nationwide study, a sizeable minority of patients who did not receive intravenous rtPA solely because of mild/improving stroke had poor short-term outcomes, raising the possibility that stroke-related disability is relatively common, even in “mild” stroke. A controlled trial of reperfusion therapy in this population may be warranted.
Impact of Extracranial–Intracranial Bypass on Cerebrovascular Reactivity and Clinical Outcome in Patients With Symptomatic Moyamoya Vasculopathy
Authors: Han Jay S. , Abou-Hamden Amal , Mandell Daniel M. , Poublanc Julien , Crawley Adrian P. , Fisher Joseph A. , Mikulis David J. , Tymianski Michael
Published: September 2011

Background and Purpose—

The purpose of this study was to evaluate in symptomatic moyamoya patients the effect of surgical revascularization on impaired cerebrovascular reactivity (CVR) and its relationship to clinical outcome.

Methods—

Brain revascularization was performed using a direct superficial temporal artery to middle cerebral artery bypass or indirect encephalo-dural–arterial synangiosis. CVR was measured pre- and 3 months postoperatively using blood oxygen level-dependent MRI during iso-oxic hypercapnic changes in end-tidal carbon dioxide. Outcomes were assessed by MRI, clinical examination, and modified Rankin Scale scores.

Results—

Fifty-five hemispheres were revascularized in 39 patients (superficial temporal artery to middle cerebral artery in 47, encephalo-dural–arterial synangiosis in 8). Surgery reversed CVR impairment in 52 hemispheres (94.5%) and in 36 of 39 patients (92.3%; Fisher exact test,
P
<0.001), and this was predictive of a patent extracranial–intracranial bypass. New, clinically silent perioperative hemorrhages, cortical foci of ischemia, or new white matter T2 hyperintensities were detected after 11 surgeries (20%), but no new lesions arose after 3 postoperative months. One patient had a clinical perioperative stroke (1.8%). In clinical follow-up, 37 of 39 patients (95%) had stable or improved modified Rankin Scale scores and 2 patients (5.1%) worsened. No patients with patent bypasses or CVR improvements exhibited new clinical symptoms, but failure of CVR improvement corresponded to a poorer long-term outcome (Fisher exact test,
P
<0.001).

Conclusions—

Cerebral revascularization surgery is a safe and effective treatment for reversing preoperative CVR defects and may prevent recurrence of preoperative symptoms. Moreover, CVR measurements may be useful in long-term follow-up and for predicting bypass patency.
Longitudinal Magnetic Resonance Imaging of Sildenafil Treatment of Embolic Stroke in Aged Rats
Authors: Ding Guangliang , Jiang Quan , Li Lian , Zhang Li , Zhang Zhenggang , Lu Mei , Li Qingjiang , Gu Steven , Ewing James , Chopp Michael
Published: September 2011

Background and Purpose—

Sildenafil provides restorative therapeutic benefits in the treatment of experimental stroke. The majority of experimental studies on treatment of stroke have been performed in young animals; however, stroke is primarily a disease of the aged. Thus, using MRI, we evaluated the effects of sildenafil treatment of embolic stroke in aged animals.

Methods—

Aged male Wistar rats (18 months) were subjected to embolic stroke and treated daily with saline (n=10) or with sildenafil (n=10) initiated at 24 hours and subsequently for 7 days after onset of ischemia. MRI measurements were performed at 24 hours and weekly to 6 weeks after embolization.

Results—

MRI and histological measurements demonstrated that sildenafil treatment of aged rats significantly enhanced angiogenesis and axonal remodeling after stroke compared to saline-treated aged rats. Local cerebral blood flow in the angiogenic area was elevated and expansion of the ipsilateral ventricle and, consequently, brain atrophy was significantly reduced in the sildenafil-treated rats.

Conclusions—

Treatment of embolic stroke in aged rats with sildenafil significantly augments angiogenesis and axonal remodeling, which increased local blood flow and reduced expansion of the ipsilateral ventricle 6 weeks after stroke compared to control aged rats. MRI can be used to investigate brain repair after stroke in aged rats.
Therapeutic Modulation of Cerebral Microhemorrhage in a Mouse Model of Cerebral Amyloid Angiopathy
Authors: Fisher Mark , Vasilevko Vitaly , Passos Giselle F. , Ventura Christopher , Quiring Daniel , Cribbs David H.
Published: September 2011

Background and Purpose—

The aging brain demonstrates frequent MRI and pathological evidence of cerebral microbleeds, which are often associated with cerebral amyloid angiopathy. To develop new therapeutic strategies for this disorder, we studied cerebral microhemorrhage in a well-characterized mouse model of cerebral amyloid angiopathy.

Methods—

Tg2576 mice were studied at ages ranging from 2 to 21 months. Spontaneous and induced microscopic bleeding was analyzed with and without a passive anti-amyloid immunization regimen and dietary supplementation of ischemic stroke prevention medication dipyridamole.

Results—

Areas of microhemorrhage were easily demonstrated and were significantly more prominent in the oldest mice and in animals treated with anti-amyloid immunotherapy. Dipyridamole supplementation in the diet generated plasma levels >790 ng/mL within the range seen clinically. Dipyridamole treatment did not worsen frequency and size of cerebral microscopic bleeding.

Conclusions—

The Tg2576 mouse is a useful model to study progression and modification of spontaneous and immunotherapy-induced cerebral microhemorrhage. Absence of microhemorrhage worsening with dipyridamole treatment suggests a potential therapeutic role of this agent when ischemic and microhemorrhagic lesions coexist.
Chronic Heart Failure and Ischemic Stroke
Authors: Haeusler Karl Georg , Laufs Ulrich , Endres Matthias
Published: September 2011

Chronic heart failure (CHF) is one of the leading causes of hospitalization, morbidity, and mortality worldwide. This review summarizes current knowledge with regard to CHF as a risk factor for ischemic stroke. CHF is associated with an increased risk of thrombus formation and is accompanied by a 2- to 3-fold increased risk of stroke. Moreover, stroke in CHF patients is associated with poor outcome and higher mortality. Available evidence for additional “vascular” stroke risk factors in heart failure patients is inconsistent and is mostly derived from cohort studies or retrospective analyses. Current guidelines recommend anticoagulation for CHF patients with concomitant atrial fibrillation but not for those in sinus rhythm. Prospective studies are needed to test whether early detection and optimal treatment of CHF reduces the burden of stroke-associated neurologic and neuropsychological sequelae.
Trust but Verify: Building Cultures of Support for the Responsibility to Protect Norm
Authors: Zuber Robert , Laso Ana Carolina Barry
Published: September 2011

Whether we wish to acknowledge it or not, trust issues permeate all security policy deliberations, including recent discussions at United Nations headquarters focused on building acceptance of the Responsibility to Protect (RtoP) norm and laying out plans for the full implementation of all three of its programmatic 'pillars.' This paper assesses resources for and commitments to trust building in three core areas – trust in the viability of the norm itself, trust in the persons most closely associated with the norm, and trust in the institutions (UN and Regional Bodies) projected to 'house' the norm and oversee all phases of its implementation. As this implementation process moves from consideration of state-focused, 'first pillar' preventive and early warning capacities to 'third pillar,' last-resort, direct responses to threats of atrocity crimes, the need for durable and dependable bonds of trust between RtoP advocates, diplomats and policymakers becomes more acute.
Some Concerns About 'The Responsibility Not to Veto'
Authors: Levine Daniel H.
Published: September 2011

Ariela Blätter and Paul D. Williams propose that the international community could more effectively end serious abuses such as genocide and crimes against humanity if the permanent five members of the UN Security Council adopted a 'responsibility not to veto;' that is, an informal agreement not to use their veto power when action to respond to genocide or mass atrocities is proposed and has the support of a simple majority on the Council. While there is much to recommend the proposal, it may not in fact promote the protection of civilians as it is intended to do. The historical record shows a number of instances where inappropriate military action was counterproductive to civilian protection, and it is not clear how easy it would have been for a military intervention to help rather than harm civilians in some cases in which intervention was not forthcoming. Ultimately, the RN2V proposal would be stronger if it were part of a package of more fundamental institutional changes, including improving the UN's ability to respond to budding crises non-violently.
Simulations of Historical and Future Trends in Snowfall and Groundwater Recharge for Basins Draining to Long Island Sound
Authors: Bjerklie David M. , Trombley Thomas J. , Viger Roland J.
Published: September 2011

A regional watershed model was developed for watersheds contributing to Long Island Sound, including the Connecticut River basin. The study region covers approximately 40 900 km2, extending from a moderate coastal climate zone in the south to a mountainous northern New England climate zone dominated by snowmelt in the north. The input data indicate that precipitation and temperature have been increasing for the last 46 years (1961–2006) across the region. Minimum temperature has increased more than maximum temperature over the same period (1961–2006). The model simulation indicates that there was an upward trend in groundwater recharge across most of the modeled region. However, trends in increasing precipitation and groundwater recharge are not significant at the 0.05 level if the drought of 1961–67 is removed from the time series. The trend in simulated snowfall is not significant across much of the region, although there is a significant downward trend in southeast Connecticut and in central Massachusetts. To simulate future trends, two input datasets, one assuming high carbon emissions and one assuming low carbon emissions, were developed from GCM forecasts. Under both of the carbon emission scenarios, simulations indicate that historical trends will continue, with increases in groundwater recharge over much of the region and substantial snowfall decreases across Massachusetts, Connecticut, southern Vermont, and southern New Hampshire. The increases in groundwater recharge and decreases in snowfall are most pronounced for the high emission scenario.
Estimation of Daily Mean Photosynthetically Active Radiation under All-Sky Conditions Based on Relative Sunshine Data
Authors: Qin Jun , Yang Kun , Liang Shunlin , Tang Wenjun
Published: September 2011

Photosynthetically active radiation (PAR) is absorbed by plants to carry out photosynthesis. Its estimation is important for many applications such as ecological modeling. In this study, a broadband transmittance scheme for solar radiation at the PAR band is developed to estimate clear-sky PAR values. The influence of clouds is subsequently taken into account through sunshine-duration data. This scheme is examined without local calibration against the observed PAR values under both clear- and cloudy-sky conditions at seven widely distributed Surface Radiation Budget Network (SURFRAD) stations. The results indicate that the scheme can estimate the daily mean PAR at these seven stations under all-sky conditions with root-mean-square error and mean bias error values ranging from 6.03 to 6.83 W m−2 and from −2.86 to 1.03 W m−2, respectively. Further analyses indicate that the scheme can estimate PAR values well with globally available aerosol and ozone datasets. This suggests that the scheme can be applied to regions for which observed aerosol and ozone data are not available.
Probability Density Functions of Liquid Water Path and Total Water Content of Marine Boundary Layer Clouds: Implications for Cloud Parameterization
Authors: Kawai Hideaki , Teixeira João
Published: September 2011

Mathematical forms of probability density functions (PDFs) of liquid water path (LWP) and total water content for marine boundary layer clouds are investigated using the homogeneity, skewness, and kurtosis of PDFs of LWP obtained from observations described in a companion paper. First, observed LWP PDF data are divided into four categories depending on the stability between 775 and 1000 hPa in order to investigate the characteristics of the PDFs of LWP depending on stability of the atmospheric boundary layer (ABL). The relationships between cloud amount and higher moments of LWP PDFs for different ABLs show different features. When the stability becomes larger, the LWP PDFs have larger homogeneity, smaller skewness, and smaller kurtosis for similar cloud amounts.

To extract useful information about the PDFs of total water content for strongly and moderately stable ABLs, the relationship between LWP PDFs and PDFs of total water content is determined by introducing a set of simple assumptions for the vertical structure of total water content in well-mixed boundary layers. By comparing the observed relationships between cloud amount and higher moments of LWP PDFs, with similar relationships deduced theoretically from various forms of PDFs of total water content, it is found that, in general, the triangular and Gaussian PDFs are a realistic approximation for PDFs of total water content in marine boundary layer clouds for strongly and moderately stable ABLs. Results concerning the correction ratio for the autoconversion rate of cloud water content to precipitation and the reduction factor for shortwave reflectance, as functions of cloud amount, are also discussed.
Estimation of Rain Intensity Spectra over the Continental United States Using Ground Radar–Gauge Measurements
Authors: Lin Xin , Hou Arthur Y.
Published: September 2011

A high-resolution surface rainfall product is used to estimate rain characteristics over the continental United States as a function of rain intensity. By defining data at 4-km horizontal resolutions and 1-h temporal resolutions as an individual precipitating or nonprecipitating sample, statistics of rain occurrence and rain volume including their geographical and seasonal variations are documented. Quantitative estimations are also conducted to evaluate the impact of missing light rain events due to satellite sensors’ detection capabilities.

It is found that statistics of rain characteristics have large seasonal and geographical variations across the continental United States. Although heavy rain events (>10 mm h−1) only occupy 2.6% of total rain occurrence, they may contribute to 27% of total rain volume. Light rain events (<1.0 mm h−1), occurring much more frequently (65%) than heavy rain events, can also make important contributions (15%) to the total rain volume.

For minimum detectable rain rates setting at 0.5 and 0.2 mm h−1, which are close to sensitivities of the current and future spaceborne precipitation radars, there are about 43% and 11% of total rain occurrence below these thresholds, and they respectively represent 7% and 0.8% of total rain volume. For passive microwave sensors with their rain pixel sizes ranging from 14 to 16 km and the minimum detectable rain rates around 1 mm h−1, the missed light rain events may account for 70% of rain occurrence and 16% of rain volume.

Statistics of rain characteristics are also examined on domains with different temporal and spatial resolutions. Current issues in estimates of rain characteristics from satellite measurements and model outputs are discussed.
Systematic Estimates of Initial-Value Decadal Predictability for Six AOGCMs
Authors: Branstator Grant , Teng Haiyan , Meehl Gerald A. , Kimoto Masahide , Knight Jeff R. , Latif Mojib , Rosati A.
Published: September 2011

Initial-value predictability measures the degree to which the initial state can influence predictions. In this paper, the initial-value predictability of six atmosphere–ocean general circulation models in the North Pacific and North Atlantic is quantified and contrasted by analyzing long control integrations with time invariant external conditions. Through the application of analog and multivariate linear regression methodologies, average predictability properties are estimated for forecasts initiated from every state on the control trajectories. For basinwide measures of predictability, the influence of the initial state tends to last for roughly a decade in both basins, but this limit varies widely among the models, especially in the North Atlantic. Within each basin, predictability varies regionally by as much as a factor of 10 for a given model, and the locations of highest predictability are different for each model. Model-to-model variations in predictability are also seen in the behavior of prominent intrinsic basin modes. Predictability is primarily determined by the mean of forecast distributions rather than the spread about the mean. Horizontal propagation plays a large role in the evolution of these signals and is therefore a key factor in differentiating the predictability of the various models.
Postprocessing of Ensemble Precipitation Predictions with Extended Logistic Regression Based on Hindcasts
Authors: Roulin Emmanuel , Vannitsem Stéphane
Published: September 2011

Extended logistic regression is used to calibrate areal precipitation forecasts over two small catchments in Belgium computed with the European Centre for Medium-Range Weather Forecasts (ECMWF) Ensemble Prediction System (EPS) between 2006 and 2010. The parameters of the postprocessing are estimated from the hindcast database, characterized by a much lower number of members (5) than the EPS (51). Therefore, the parameters have to be corrected for predictor uncertainties. They have been fitted on the 51-member EPS ensembles, on 5-member subensembles drawn from the same EPS, and on the 5-member hindcasts. For small ensembles, a simple “regression calibration” method by which the uncertain predictors are corrected has been applied. The different parameter sets have been compared, and the corresponding extended logistic regressions have been applied to the 51-member EPS. The forecast probabilities have then been validated using rain gauge data and compared with the raw EPS. In addition, the calibrated distributions are also used to modify the ensembles of precipitation traces.

The postprocessing with the extended logistic regression is shown to improve the continuous ranked probability skill score relative to the raw ensemble, and the regression calibration to remove a large portion of the bias in parameter estimation with small ensembles. With a training phase limited to a 5-week moving window, the benefit lasts for the first 2 forecast days in winter and the first 5 or 6 days in summer. In general, substantial improvements of the mean error and of the continuous ranked probability score have been shown.
A Comprehensive Assessment of CFS Seasonal Forecasts over the Tropics*
Authors: Sooraj K. P. , Annamalai H. , Kumar Arun , Wang Hui
Published: September 2011

The 15-member ensemble hindcasts performed with the National Centers for Environmental Prediction Climate Forecast System (CFS) for the period 1981–2005, as well as real-time forecasts for the period 2006–09, are assessed for seasonal prediction skills over the tropics, from deterministic (anomaly correlation), categorical (Heidke skill score), and probabilistic (rank probability skill score) perspectives. Further, persistence, signal-to-noise ratio, and root-mean-square error analyses are also performed. The CFS demonstrates high skill in forecasting El Niño–Southern Oscillation (ENSO) related sea surface temperature (SST) anomalies during developing and mature phases, including that of different types of El Niño. During ENSO, the space–time evolution of anomalous SST, 850-hPa wind, and rainfall along the equatorial Pacific, as well as the mechanisms involved in the teleconnection to the tropical Indian Ocean, are also well represented. During ENSO phase transition and in the summer, the skill of forecasting Pacific SST anomalies is modest. An examination of CFS ability in forecasting seasonal rainfall anomalies over the U.S. Affiliated Pacific Islands (USAPI) indicates that forecasting the persistence of dryness from El Niño winter into the following spring/summer is skillful at leads > 3 months. During strong El Niño years the persistence is predicted by all members with a 6-month lead time. Also, the model is skillful in predicting regional rainfall responses during different types of El Niño. Since both deterministic and probabilistic skill scores converge, the suggestion is that the forecast is useful. The model’s skill in the real-time forecasts for the period 2006–09 is also discussed. The results suggest the feasibility that a dynamical-system-based seasonal prediction of precipitation over the USAPI can be considered.
Women Psychologists
Authors: Scott Marjorie , Brown Frances , Marshall Karen , Judd Emily Jensen , Braboy LaTisha , Jhaveri-Mehta Sachi
Published: September 2011

Six women from the same graduate school of psychology, one faculty member and one student from each year of the doctoral program, came together to learn about each other, the developmental experiences of women psychologists, and to supplement the largely overlooked documented histories of women psychologists. As a result, these women, whose personal histories differed greatly, began a project to record their individual and collective life and career development experiences with the ultimate goals of (a) identifying predominant characteristics of the first women psychologists, (b) comparing their paths with those who led the way for women entering the profession, and (c) elucidating for today’s women psychologists the rich legacy of the pioneers in the field, including the familiar challenges of balancing life and work. A review of the literature was undertaken and the consensual qualitative research model was used to analyze data. The core themes revealed were (a) spirited personality traits; (b) constraints of culture, gender, race, and social class; and (c) development influenced by relationships and role models. These themes echoed the experiences of the earliest women psychologists who came from privileged backgrounds; the current women psychologists were from more diverse backgrounds and are seen as women of opportunity.
From One Skill Shortage to the Next: The Australian Construction Industry and Geographies of a Global Labour Market
Authors: McGrath-Champ Susan , Rosewarne Stuart , Rittau Yasmin
Published: September 2011

The initial prosperity of the 21st century’s first decade was accompanied in Australia by a skills shortage. Despite a relatively brief hiatus created by the ‘global financial crisis’, significant skills shortages have re-emerged. Drawing on multi-scalar insights into the construction industry in Australia and worldwide, and qualitative research in Australia, this article highlights the geographically constituted nature of the construction industry and the contradictory interplay of local labour force formation with increased recourse to the global labour market to meet workforce needs. More broadly, the article demonstrates how an appreciation of the geographical nature of an industry can yield new insights into work and employment.
Protest 2.0: online interactions and Aboriginal activists
Authors: Petray Theresa Lynn
Published: September 2011

Social movements, like every other aspect of life, have become increasingly reliant on the internet for networking, information sharing and coalition building. This is the case even for disadvantaged groups with few resources and less capacity for utilizing computers and the internet. Aboriginal activists in Townsville have been slow to exert their presence on the web, but are gradually becoming savvy in the use of electronic networking in furthering their cause. They rely on listservs, blogs and, more recently, social networking sites to make their struggle known to a wide audience. In addition to the use of Web 2.0 to supplement ‘offline’ activism, there is a new form of ‘virtual’ activism emerging. The rise in ‘push-button activism’ increases the opportunities for everyday engagement with the state by social movement participants. However, it also changes the notion of participation as marches and demonstrations give way to electronic petitions and Facebook fan pages.
Gendered homophobia in sport and coaching: Understanding the everyday experiences of lesbian coaches
Authors: Norman Leanne
Published: September 2011

The purpose of this article is to discuss a theory of everyday gendered homophobia as a way of understanding lesbian coaches’ experiences of their profession. I discuss the need to gain a better comprehension of homophobia achieved through deconstructing women’s day-to-day experiences of professional coaching, examining how their lives are individually organized along multiple power lines, namely sexual orientation and gender. Through this, it is possible to connect the macro-structure of sport to the micro- and recognize the everyday inferiorizations that take place within the participants’ lives. The main focus of the article is to explore the power of understanding the everyday and present the key conceptual issues and processes underpinning a theory of everyday gendered homophobia. The conception of everyday gendered homophobia is based upon data from in-depth semi-structured interviews with 10 professional women coaches who identified themselves as lesbian, from both individual and team sports within the UK.
Male and female robots
Authors: Da Rold Federico , Petrosino Giancarlo , Parisi Domenico
Published: September 2011

A population of male and female robots evolves in an environment in which to remain alive they must eat the food contained in the environment and to reproduce they must mate with a robot of the opposite sex. The only difference between male and female robots is that after mating males can mate again (reproductively) while females have a fixed period during which they are nonreproductive. The results show that males have a greater variance in reproductive success than females; they tend always to be very active looking for the ‘‘scarce resource’’ constituted by reproductive females and eating any food they are able to find while they are looking for reproductive females. Reproductive females are less active than males and they adopt the reproductive strategy of waiting for males to find and mate with them. In contrast, nonreproductive females are as active as males, but they only look for food and are not interested in anything else. We also find a number of differences between males and females in their preferences for different types of food, and in offspring care if males do not have parental certainty.
Conceptualizing Mindfulness and Acceptance as Components of Psychological Resilience to Trauma
Authors: Thompson Rachel W. , Arnkoff Diane B. , Glass Carol R.
Published: September 2011

Mindfulness- and acceptance-based conceptualizations of PTSD implicate experiential avoidance and non-mindful behavior in the etiology and maintenance of the disorder. If experiential avoidance is associated with vulnerability to PTSD, then a mindful and accepting orientation toward experience may confer psychological resilience following exposure to trauma. This article examines how mindfulness- and acceptance-based theories of psychopathology relate to risk of and resilience to PTSD. Research is reviewed dealing with the impact of experiential avoidance, avoidant coping, dissociation, acceptance, and mindfulness on PTSD symptom severity and posttraumatic functioning. This review suggests that trait mindfulness and acceptance are associated with greater psychological adjustment following exposure to trauma, while experiential avoidance, persistent dissociation, and coping strategies involving emotional disengagement are associated with greater PTSD symptom severity and related psychopathology. Methodological challenges are explored and suggestions for future research and PTSD prevention programs are discussed.
Community-Based Services and Interventions for Adults With Disabilities Who Have Experienced Interpersonal Violence: A Review of the Literature
Authors: Lund Emily M.
Published: September 2011

This study provides a review of the peer-reviewed literature from 1995 to 2010 on violence-related service, prevention, and intervention programs for people with disabilities. A comprehensive literature search resulted in a total of 16 articles, 6 related to service programs and 10 related to intervention and prevention programs. The services articles revealed a noticeable disconnect between the violence services programs’ perceived accessibility and the perception of their accessibility in the disability community. Most of the intervention and prevention articles focused exclusively on abuse prevention for adults with intellectual disabilities and generally had small samples and lacked controlled conditions. Very few methods of abuse treatment for people with disabilities have been empirically evaluated. Efforts should be made to improve accessibility and increase cross-collaboration between domestic violence services and disability service organizations, and there is a need for accessible, culturally sensitive, and rigorously tested abuse interventions and prevention programs for women and men with diverse disabilities.
Victims’ Influence on Intimate Partner Violence Revictimization: A Systematic Review of Prospective Evidence
Authors: Kuijpers Karlijn F. , van der Knaap Leontien M. , Lodewijks Ilse A. J.
Published: September 2011

Foa, Cascardi, Zoellner and Feeny developed two models of women’s influence on intimate partner violence (IPV), which integrate victim-related variables associated with the cessation or continuation of partner violence (i.e., repeat IPV). One of the models focuses on psychological factors while the other centers on environmental factors. Central to both models are three key factors: partner violence; psychological difficulties; and resilience. Despite the appeal of these models, empirical, prospective research that specifically tests these models appears to be lacking. This article describes a systematic review of the available literature that examines the prospective link between the three key factors of the models and the risk of IPV revictimization. A synthesis of 15 studies reveals that Foa et al.’s models of revictimization are partly supported by prior prospective research. It is beyond doubt that the key factor partner violence (involving the severity and frequency of prior IPV) is a strong predictor for IPV revictimization; the evidence regarding victims’ psychological difficulties and resilience is more mixed. Findings are discussed in terms of implications for practice and research and might enable practitioners to help victims to take control of their situations and to contribute to their empowerment. The importance of future prospective research into dynamic, victim-related variables is emphasized, in order to further support Foa’s models of victims’ influence on IPV revictimization.