bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamical Downscaling of Global Analysis and Simulation over the Northern Hemisphere
Authors: Kanamaru Hideki , Kanamitsu Masao 
Published: July 2008

AbstractAs an extreme demonstration of regional climate model capability, a dynamical downscaling of the NCEP–NCAR reanalysis was successfully performed over the Northern Hemisphere. Its success is due to the use of the scale-selective bias-correction scheme, which maintains the large-scale analysis of the driving global reanalysis in the interior of the domain where lateral boundary forcing has very little control. The downscaled analysis was found to produce reasonable regional details by comparison against 0.5° gridded analysis from the Climatic Research Unit of the University of East Anglia. Comparisons with smaller-area regional downscaling runs in India, Europe, and Japan using the same downscaling system showed that there is no degradation of quality in downscaled climate analysis by expanding the domain from a regional scale to a hemispherical scale.
Impact of NOAA Ground-Based GPS Observations on the Canadian Regional Analysis and Forecast System
Authors: Macpherson S. R. , Deblonde G. , Aparicio J. M. , Casati B. 
Published: July 2008

Abstract
Half-hourly GPS zenith tropospheric delay (ZTD) and collocated surface weather observations of pressure, temperature, and relative humidity are available in near–real time from the NOAA Global Systems Division (GSD) research GPS receiver network. These observations, located primarily over the continental United States, are assimilated in a research version of the Environment Canada (EC) regional (North America) analysis and forecast system. The impact of the assimilation on regional analyses and 0–48-h forecasts is evaluated for two periods: summer 2004 and winter 2004/05. Forecasts are verified against radiosonde, rain gauge, and NOAA GPS network observations.
The impacts of GPS ZTD and collocated surface weather observations for the summer period are generally positive, and include reductions in forecast errors for precipitable water, surface pressure, and geopotential height. It is shown that the ZTD data are primarily responsible for these forecast error reductions. The impact on precipitation forecasts is mixed, but more positive than negative, especially for the central U.S. region and for forecasts of larger precipitation amounts. Assimilation of the collocated surface weather data with ZTD contributes to the positive impact on precipitation forecasts for the central U.S. region. The NOAA GPS network data also have a positive impact on tropical storm system forecasts over the southeast United States, in terms of both storm track and precipitation. Impacts for the winter case are generally smaller because of the lower precipitable water (PW) over North America, but some positive impacts are observed for precipitation forecasts. The greatest regional impacts in the winter case are observed for the southeast U.S. (the Gulf) region where average PW is highest.
Impact of SSM/I Observations Related to Moisture, Clouds, and Precipitation on Global NWP Forecast Skill
Authors: Kelly G. A. , Bauer P. , Geer A. J. , Lopez P. , Thépaut J-N. 
Published: July 2008

AbstractThis paper presents the results from the Observing System Experiments (OSEs) with the current ECMWF data assimilation and modeling system for quantifying the impact on both analysis and forecast quality of Special Sensor Microwave Imager (SSM/I) observations sensitive to moisture and clouds as well as precipitation. SSM/I radiances have been assimilated operationally in clear-sky areas for 8 yr and in cloud- and rain-affected areas since June 2005. This paper examines experiments set up such that clear-sky and rain-affected observations were either added to a baseline with a restricted observing system configuration or withdrawn from the full system. The experiment duration was 10 weeks of which the first 14 days were excluded from the evaluation to allow the system to lose the memory of the initial conditions at day −1.It is shown that both clear-sky and rain-affected observations account for the bulk correction of moisture in the ECMWF analysis. SSM/I data adds 1 day of forecast skill over the first 48 h when evaluated in addition to a baseline-observing system. In the tropics, the rain-affected data contributes more skill to the moisture forecast than the clear-sky data at 700 hPa and above. In the Northern and Southern Hemispheres, the effect is generally weaker and slightly in favor of clear-sky observations. A similar performance can be seen with respect to the wind vector forecast skill, which reflects the connection between the analysis of moisture and dynamics.
The Influence of Ice Cover on Two Lake-Effect Snow Events over Lake Erie
Authors: Cordeira Jason M. , Laird Neil F. 
Published: July 2008

Abstract
It is generally understood that extensive regions of significant lake ice cover impact lake-effect (LE) snow storms by decreasing the upward heat and moisture fluxes from the lake surface; however, it is only recently that studies have been conducted to more thoroughly examine this relationship. This study provides the first examination of Great Lakes LE snow storms that developed in association with an extensively ice-covered lake. The LE snow events that occurred downwind of Lake Erie on 12–14 February 2003 and 28–31 January 2004 produced maximum snowfall totals of 43 and 64 cm in western New York state, respectively. The presence of widespread ice cover led these snows to be less anticipated than snowfalls from Lake Ontario, which had limited ice cover. For both events, a variety of ice-cover conditions and meso- and synoptic-scale factors (i) helped support LE snow storm development, (ii) lead to the transitions in LE convective type, and (iii) resulted in noteworthy snowfalls near Lake Erie. Thinner ice cover along with favorable fetch directions during the 2004 event likely aided the development of more significant snowband time periods and the resulting greater snowfall. Although Lake Erie had regions with lower ice concentration during the 2003 event, thicker ice cover was present across a greater area of the lake, fetch directions during lake-effect time periods were positioned over higher ice concentration regions, and snowbands had a shorter duration and impacted the same region to a lesser degree than the 2004 case.
A Vortex-Based Perspective of Eastern Pacific Tropical Cyclone Formation
Authors: Davis Christopher , Snyder Chris , Didlake Anthony C. 
Published: July 2008

Abstract
Tropical cyclone formation over the eastern Pacific during 2005 and 2006 was examined using primarily global operational analyses from the National Centers for Environmental Prediction. This paper represents a “vortex view” of genesis, adding to previous work on tropical cyclone formation associated with tropical waves. Between 1 July and 30 September during 2005 and 2006, vortices at 900 hPa were tracked and vortex-following diagnostic quantities were computed. Vortices were more abundant during periods of an enhanced “Hadley” circulation with monsoon westerlies around 10°N in the lower troposphere. This zonally confined Hadley circulation was significantly stronger during the genesis of developing vortices. Developing vortices were stronger at the outset, with a deeper potential vorticity maximum, compared to nondeveloping vortices. This implies that developing disturbances were selected early on by favorable synoptic-scale features.
The characteristic time-mean reversal of the meridional gradient of absolute vorticity in the lower troposphere was found to nearly vanish when the aggregate contribution of strong vortices was removed from the time-mean vorticity. This finding implies that it is difficult to unambiguously attribute development to a preexisting enhancement of vorticity on the synoptic scale. The time-mean enhancement of cyclonic vorticity primarily results from the accumulated effect of vortices. It is suggested that horizontal deformation in the background state helps distinguish developing vortices from nondevelopers, and also biases the latitude of development poleward of the climatological ITCZ axis.
Morphologic and Functional Changes of Left Ventricle in Dialyzed Patients After Treatment with Recombinant Human Erythropoietin (r-HuEPO)
Authors: Jeren-Strujić B. , Raos V. , Jeren T. , Horvatin-Godler S. , Jeren-Strujić B. 
Published: July 2008

Dysfunction of the cardiovascular system is a common complication of chronic renal insufficiency. Many factors can cause left ventricular hypertrophy (LVH), and hyperten sion and anemia are among them. They play an important role in the pathogenesis of LVH as well as in the development of cardiac dysfunction. Echocardiography enables early detection of functional macrocirculatory changes as well as adequate measuring of cardiac structures and LV mass. Anemia of end-stage chronic renal insufficiency (ESRD) is only one among its many complications and has complex pathogenesis; one of the primary factors causing anemia is insufficient production of erythropoietin, a leading factor in the production of erythropoiesis. Anemia correction with recombinant human erythropoietin (r-HuEPO) in ESRD has a positive effect on the cardiovascular system. In this study the authors examined the hemodynamic effect of erythropoietin in anemic patients undergoing hemodialysis and observed its positive effect on the cardiovascular system. Twenty-two patients were included in the study (13 men and 9 women) mean age x=39.5 years. All patients were dialyzed three times a week for 4 hours and were all treated, according to protocol, with r-HuEPO for 8 months. Left ventricular mass was measured by the Penn Convention formula. The authors noticed the effectiveness of this therapy through an increase of hemoglobin of 35% and of hematocrit of 34% and a direct effect on the cardiovascular system. Echocardiographic findings showed decrease of LV mass from 391 to 274 mg (30%). The correction of renal anemia with erythropoietin leads to structural microcircula tory changes and partial morphologic regression of preexistent LVH, which again leads to regression of cardiac dysfunctions and improved hemodynamic effect, physical capacity, and cardiopulmonary status, and ultimately better quality of life for dialyzed patients.
Quantitative Assessment of Peripheral Arterial Obstruction in Raynaud's Phenomenon: Development of a Predictive Model of Obstructive Arterial Cross-Sectional Area and Validation with a Doppler Blood Flow Study
Authors: Seitz Walter S. , Kline Howard J. , McIlroy Malcolm B. 
Published: July 2008

The objective of this study was to develop a method for the analytical assessment of arterial obstruction in conditions of Raynaud's phenomenon capable of providing diag nostic criteria. Numerous attempts have been made to determine and quantify arterial obstruction in terms of Doppler ultrasound measurements of arterial blood velocity. Absent from these methods is a formulation that allows an assessment of arterial obstruc tion based on the obstructed area as derived from direct measurement. The authors used spectral analysis of velocity signals from a pulsed, range-gated Doppler ultrasonic instru ment to make quantitative measurements of arterial blood flow velocity in hands of normal subjects and persons with Raynaud's phenomenon. They measured the peak and mean velocity during the cardiac cycle and the time integral of the velocity signal over the cardiac cycle. These measurements for two distinct hemodynamic states induced by temperature changes allowed them to calculate the fractional change in arterial cross- sectional area produced by the change in temperature through the application of a hydraulic model of digital arterial circulation. They found an equation expressing frac tional obstructed area expressed as: dA/A = 2( dD - τ dν - ντ)/( D + ν dτ), where D is the time integral of the velocity signal; τ is the blood flow interval, ν is the blood velocity; and dD, dτ and dv are the differences in D, τ, and ν at two different hemodynamic states produced by two different temperature states. Their findings suggest that over a temper ature range of 35°-25°C, normal subjects experience 0.05/°C reduction in cross-sectional area while Raynaud subjects experience a reduction of 5.8%/°C. The results, based on findings in 13 subjects, suggest that Doppler ultrasound can differentiate persons with Raynaud's phenomenon from normal subjects. Additionally, the hydraulic model appears to offer the potential of assessing relative stenotic area in other arterial obstructive diseases.
Venous Thromboembolism from Air Travel
Authors: Belcaro Gianni , Geroulakos George , Nicolaides Andrew N. , Myers Kenneth A. , Winford Michelle 
Published: July 2008

The LONFLIT study was planned to evaluate the incidence of deep venous thrombosis (DVT) occurring as a consequence of long flights. In the Lonflit 1 study 355 subjects at low-risk for DVT and 389 at high-risk were studied. Low-risk subjects had no cardiovascular disease and used no drugs. All flights were in economy class. The average flight duration was 12.4 hours (range, 10-15 hr). The mean age of the studied subjects was 46 years (range 20-80 yr, SD 11; 56% males). DVT diagnosis was made by ultrasound scans after the flights (within 24 hours). In low-risk subjects no events were recorded while in high-risk subjects 11 had DVT (2.8%) with 13 thromboses in 11 subjects and 6 superficial thromboses (total of 19 thrombotic events in 389 patients [4.9%]). In the Lonflit2 study the authors studied 833 subjects (randomized into 422 control subjects and 411 using below-knee stockings). Mean age was 44.8 years (range, 20-80 yr, SD 12; 57% males). The average flight duration was 12.4 hours. Scans were made before and after the flights. In the control group there were 4.5% of subjects with DVT while only 0.24% of subjects had DVT in the stockings group. The difference was significant. The incidence of DVT observed when subjects were wearing stockings was 18.75 times lower than in controls. Long-haul flights are associated to DVT in some 4-5% of high-risk subjects. Below-knee stockings are beneficial in reducing the incidence of DVT.
Anomalous Circumflex Coronary Artery: Benign or Predisposed to Selective Atherosclerosis
Authors: Samarendra Padmaraj , Kumari Sarita , Hafeez Mohammed , Vasavada Balendu C. , Sacchi Terrence J. 
Published: July 2008

Anomalous origin of the circumflex coronary artery from the right sinus of Valsalva is the most common coronary anomaly and is usually considered benign. Although several researchers in the past believed that aberrancy predisposes this vessel to accelerated atherosclerosis, this could not get wide acceptance owing to lack of convincing data. To examine the suggestion that atherosclerosis affects the anomalous circumflex artery more severely, the authors reviewed the clinical and angiographic features of patients with this anomaly identified from 2,684 coronary angiography procedures performed between January 1998 and March 2000 at their institution. The degree of atherosclerotic narrowing in the anomalous artery was compared with that in other coronary arteries in the same patient as well as in the nonanomalous circumflex arteries in controls. For comparison 3 control subjects were selected for each patient with anomalous circumflex artery, matched by age, sex, and clinical presentations. The results showed earlier and greater degree of atherosclerotic narrowing of the anomalous artery as compared to the other coronary arteries in the same patients as well as to nonanomalous circumflex arteries of age- and gender-matched control subjects with similar clinical characteristics. However, this predilection for atherosclerosis was evident only in anomalous vessels arising from the right side and pursuing a retroaortic course. The anomalous artery was responsible for myocardial infarction in 3 patients, all of whom were 60 years or older. Two of the patients with this anomaly and myocardial infarction underwent successful angioplasty with stent placement for symptomatic relief.
Late Systolic Wave on Brachial Artery Blood Flow Velocity Pattern in Patients with Coronary Artery Disease and its Relation to Vascular Stiffness
Authors: Güler Niyazi , Eryonucu Beyhan , Bilge Mehmet , Etlik Ömer , Erkoç Reha , Sakarya Mehmet Emin 
Published: July 2008

Duplex-Doppler study typically exhibits triphasic brachial artery blood flow velocity pattern in subjects classified as normal without clinically evident atherosclerotic complications, heart disease, hypertension, or diabetes mellitus. In this study, the authors described the late systolic wave on the brachial artery blood flow velocity pattern in patients with coronary artery disease and investigated the relation between late systolic wave and vascular stiffness. Blood flow profile and velocity of the brachial artery were determined noninvasively by ultrasound pulsed-Doppler technique under the guidance of a B-mode ultrasound image in 96 patients with coronary artery disease (CAD). The control group consisted of 23 healthy subjects with no or maximally 2 risk factors (only among age, cigarette smoking, obesity, and gender) for vascular disease. None of the patients and controls had clinical evidence of arterial disorders at upper extremities. In 32 patients (33%) with CAD, a late systolic wave was observed in the brachial artery Doppler study. On the other hand, no late systolic wave was observed in the healthy subjects. In addition, multivessel disease, hypertension, advanced age, diabetes, and smoking were significantly more frequent in patients with the late systolic wave. In conclusion, peripheral arterial abnormalities induced by vascular stiffness may produce alterations in regional wave reflections, and the normal triphasic pattern of the brachial artery blood flow may change by the appearance of the late systolic wave.
Two-Dimensional Echo Doppler Findings in Juvenile and Adult Onset Ankylosing Spondylitis with Long-Term Disease
Authors: Jiménez-Balderas F.J. , García-Rubi D. , Pérez-Hinojosa S. , Arellano J. , Yáñez P. , Sanchez M.L. , Camargo-Coronel A. , Zonana-Nacach A. 
Published: July 2008

The authors' objective was to determine by 2-dimensional echo Doppler (2DECHO) the cardiac abnormalities in juvenile onset ankylosing spondylitis (JOAS) and adult onset ankylosing spondylitis (AOAS) in male patients with long-term disease. Twenty patients with JOAS, 31 with AOAS, and 20 healthy controls of the same age and gender without cardiopulmonary symptoms were studied. Using 2DECHO, the heart dimensions were determined according to American Society of Echocardiography guidelines. The left ventricle ejection fraction (LVEF) was calculated by Teichholz's formula. Cardiomyopathy was established when 2DECHO had diminished LVEF. Statistics used were the Student t and Fisher test, χ2, and ANOVA. Ninety percent of JOAS and 51 % of AOAS patients were B27+ (p = 0.005). The disease duration was 19.3 ±8.8 years in JOAS and 14.8 ± 12.8 years in AOAS (p = NS). Age at the time of the study was 30.7 ±9.9 years in JOAS vs 40.3 ± 12.7 in AOAS (p = 0.003), and vs 40.2 ± 17 years in controls (p = NS). There was a higher frequency of cardiomyopathy in AOAS (32.2%) than in JOAS (25%) and the controls (0%) (p = 0.01). Patients with JOAS had a higher mitral valve gradient (25%) than AOAS patients (19%, p = NS) and controls (0%, p = 0.04). Abnormal aortic ring reflectance was shown in 19% of AOAS vs 0% abnormalities in JOAS and controls (p = 0.01). The aortic root diameter was increased in 58% of AOAS, 30% of JOAS, and 0% of controls (p = 0.001). The frequency of 2DECHO abnormalities was increased in cardiopulmonary asymptomatic spondylitis patients. Despite the high frequency of B27+, JOAS had a lower frequency of aortic abnormalities than AOAS. Mitral valve gradient was found in JOAS and in AOAS that could contribute to a decreased ejection fraction and to left ventricular dysfunction.
Coronary Artery Disease and Periodontal Disease: Is There a Link?
Authors: Abou-Raya Suzan , Naeem Amr , Kheir Hassan Abou-El , El Beltagy Sheriff 
Published: July 2008

Background: Cardiovascular disease is the number one killer worldwide. The so-called classic risk factors of coronary heart disease do not account for all of its clinical and epidemiological features. Recent evidence suggests that certain infections, among them dental infections and in particular periodontal disease, are involved in the pathogenesis of coronary artery disease. Aim: To evaluate the association between periodontal disease and coronary artery disease. Patients and Methods: Fifty patients referred for diagnostic coronary angiography were assessed for periodontal disease. All patients underwent a thorough physical examination, routine laboratory testing, cardiac evaluation and dental examination which included panto mography x-ray evaluation. Results: Pantomography x-rays and coronary angiograms of the participants were scored blindly by a dentist and cardiologists respectively. The association between periodontal disease and coronary atheromatosis remained significant after adjustment for age, smoking, blood lipids, body mass index, hypertension and the presence of diabetes. Implications: Periodontal disease was still significantly associated after all the known risk factors were accounted for. The implication here is that periodontal disease could be a potential risk factor for heart disease by predisposing the individual to chronic low-grade infec tions. If so, then dental health becomes an important parameter for medical health.
Exercise First-Pass Radionuclide Assessment of Left and Right Ventricular Function and Valvular Regurgitation in Symptomatic Mitral Valve Prolapse
Authors: Lumia Frank J. , LaManna Margaret M. , Atfeh Mowaffak , Maranhao Vladir 
Published: July 2008

The changes in right ventricular (RV) and left ventricular (LV) function and in regurgitant fractions on first-pass exercise radionuclide angiography (RNA) were assessed in 29 consecutive patients with symptomatic mitral valve prolapse (MVP). The mean right ventricular ejection fraction (RVEF) was 35±8% at rest and 46±15% after exercise (p < 0.001). The mean left ventricular ejection fraction (LVEF) was 62 ± 11 % at rest and 74±13% after exercise (p < 0.001) . Seven of 29 patients had an abnormal RV response and 6 had an abnormal LV response. Eight had abnormal wall motion after exercise. A total of 12/29 patients (41 %) had one or more abnormalities. The mean left-sided regurgitant fraction before exercise was 27±17% in 21/29 patients (72%) and 31±21% after exercise (p=ns) . An additional 5 pa tients (17%) developed left-sided regurgitation after exercise. These fmdings indicate that wall motion abnormalities and abnormal RVEF and LVEF responses to exercise occur in symptomatic MVP patients. In addi tion, 26/29 (89.6%) had left-sided regurgitation after exercise. Since the presence of a murmur did not correlate with the presence of mitral regurgitation by RNA, then symptomatic patients with MVP should have first- pass exercise RNA to assess the presence of regurgitation at rest and after exer cise. Antibiotic prophylaxis is recommended in MVP patients with systolic mur murs or with regurgitation. Since patients without murmurs can have regurgi tation, further study is necessary to determine the need for endocarditis pro phylaxis in these patients.