bluuebunny/crossref_metadata_2025 huggingface dataset:
Effector Mechanisms in the Spontaneous Autoimmune Thyroiditis of Obese Strain (OS) Chickens: Analysis of Cytotoxic Cells
Authors: Boyd Richard L. , Wick Georg
Published: July 2009

Different forms of cellular cytotoxicity that may constitute potential effector mechanisms in the spontaneous autoimmune thyroiditis (SAT) arising in Obese strain (OS) chickens have been investigated. A microcytotoxicity assay (MCA) employing 51Cr-labelled-, thyroglobulin (Tg) coated-chicken red blood cells (Tg-CRBC) was used to detect cells mediating Tg-specific direct cellular cytotoxicity (DCC). Tg-CRBC presensitized with anti-Tg autoantibody (Tg-AAB) obtained from high titer OS sera served as targets for antibody-dependent cell-mediated cytotoxicity (ADCC). Tannic acid-only treated CRBC (TA-CRBC) were used simultaneously as specificity controls for DCC and also as targets for cells eliciting spontaneous cellular cytotoxicity (SCC) to surface-modified normal cells. The results demonstrated that Tg-specific cytotoxic cells exist in the OS and thus represent an effector mechanism in SAT, in addition to the previously well-documented role of antibody. This DCC appears to be unrelated to the presence and titer of circulating Tg-AAb. It is present in highest levels in the peripheral blood of OS chickens, but in only 55% of the animals tested, indicating either a secondary importance to humoral immunity in the disease process or the possibility of different effector mechanisms prevailing in different birds. There were no overall differences in ADCC between OS and normal chickens when the two strains were considered as a whole. Chronological analysis, however, revealed very low ADCC in the peripheral blood of young OS birds, followed by a later elevation above that in the normal control chickens. Destruction of the gland by ADCC may be initiated via maternally-derived of in situ-produced anti-Tg antibody. No overall significant differences in SCC were observed between OS and normal chickens.
Asbestos-Induced Alteration of Human Peripheral Blood Monocyte Activity
Authors: Doll James , Bozelka Brian E. , Goldbach Susan , Añorve-López Eliseo , Salvaggio John E.
Published: July 2009

Incubation of chrysotile and anthophyllite asbestos fibers with normal human peripheral blood monocytes resulted in significant suppression of monocyte metabolic activity as measured by chemiluminescence. Both fiber types were cytotoxic to monocytes and depressed monocyte phagocytosis of latex beads. We conclude that asbestos-induced monocyte cytotoxicity could result in release of lysosomal enzymes and/or degradation products which contribute to fibrosis in asbestosis. The depression of phagocytosis and microbicidal function may contribute to the increased incidence of carcinogenesis observed in asbestosis.
Immune Responses to Mouse Neuroblastoma C1300
Authors: Penta Dennis Della , Cipuzak Patricia M. , Phillips Mildred E.
Published: July 2009

A 5lCr microcytotoxicity assay was used to study the kinetics of lymph-node- and spleen-cell-mediated cytotoxicity of A/JAX hosts following a single inoculum of the in vivo grown syngeneic neuroblastoma C1300. Lymph node cells (LNCs) demonstrated cytotoxicity which peaked at day 9, decreased as the tumor approached the 0.5-gram weight and increased again as the tumors grew. The increase in cytotoxicity following the depressed state was significantly greater than the initial peak, particularly in those mice bearing large tumors. Three groups of A/JAX mice were evaluated: mice receiving tumor cells alone; mice that were either thymectomized or splenectomized prior to inoculation, and mice that rejected the tumor. The C57B1/6 served as an allogeneic comparison. Significant cytotoxicity was detected earlier with allogeneic LNCs than with spleen cells. Thymectomy and splenectomy elicited syngeneic LNC immune responses below or equal to the level found in nonimmune A/JAX hosts.
Arachidonic Acid Metabolism in Skin: Experimental Contact Dermatitis in Guinea Pigs
Authors: Ruzicka Thomas , Printz Morton
Published: July 2009

The cutaneous metabolism of exogenous arachidonic acid and endoperoxide (PGH2·) to prostaglandins and hydroxy-fatty acids was investigated in experimental contact dermatitis in guinea pigs and compared to normal skin, unsensitized animals treated with the allergen dinitrochlorobenzene, and Trafuril®-induced irritant dermatitis. The main alterations of cutaneous arachidonate metabolism in contact dermatitis comprise: (1) an inhibition of PGD2 synthesis; (2) a switch from predominant PGD2 production to a predominance of PGE2 and (3) a marked inhibition of the lipoxygenase activity.
Detection of Basophil Sensitization by IgE Antibodies to Nuclear Antigens in Connective Tissue Diseases
Authors: Camussi Giovanni , Tetta Ciro , Benveniste Jacques
Published: July 2009

Responses of the IgE type to various nuclear antigens have been explored using the human basophil degranulation test (HBDT) to single (SS) and double-stranded (DS) deoxyribonucleic acid (DNA), nuclear ribonucleoprotein (nRNP), and Sm antigens. This study was conducted on systemic lupus erythematosus (SLE) patients as compared to rheumatoid arthritis (RA), polymyositis (PM), scleroderma (SCL) and mixed connective tissue disease (MCTD). SLE and MCTD patients showed a high level of basophil degranulation to the four antigens. Degranulation to nRNP protein was higher in MCTD than in SLE cases. HBDT to the four antigens were constantly negative in control donors and in RA, PM and SCL. Basophil degranulation to DSDNA in SLE was blocked by previous exposure of the blood to anti-human-IgE antiserum. These results exemplify the specificity of the HBDT, making this simple and fast test a useful tool in the diagnosis of connective tissue diseases.
Immunomodulating Effects of 13-cis-Retinoic Acid on the IgE Response of BALB/c Mice
Authors: Barnett John B.
Published: July 2009

The results reported here are an extension of our previously reported studies on the adjuvant effects of 13-cis-retinoic acid (13-cRA). Previous results, as well as those reported herein, show the lack of a primary IgE response with elevated and sustained secondary IgE responses in animals treated with 13-cRA. It was determined that this lack of a primary IgE response was not due to overt immunotoxicity by 13-cRA, suggesting that 13-cRA is priming a population of memory cells; however, either the formation of suppressor cells or the lack of an appropriate stimulus at the time of primary immunization also prevented a demonstrable primary IgE antibody response. It was also demonstrated that the absence of a primary response was not due to a sensitivity of the immune system to the timing of the administration of 13-cRA relative to immunization, as all animals given 13-cRA at either d0ay ––2, ––1, 0, 1 2, or 3 relative to primary immunization showed no primary response but high secondary IgE responses. These experiments, which closely mimic the clinical treatment regimen, indicate that patients receiving retinoid therapy should be closely monitored for immunological side effects, such as immediate hypersensitivity to environmental allergens.
Peripheral Localisation of an IgE Immune Response at Axillary Lymph Nodes Draining the Site of a Local Parasitic Infection
Authors: Chassoux Danièle , Bazin H.
Published: July 2009

Wistar-Furth rats were infected subcutaneously with L3 larvae of Dipetalonema viteae, filaria of Meriones libycus. Lymph nodes draining the site of immunization contained numerous IgE-staining cells identified as lymphoid cells. In other lymphoid tissues, IgE-staining cells were rare. They were absent in the lamina propria of the small intestine. These data support the view that IgE lymphoid precursors are present in peripheral lymph nodes.
Cyclosporin A Inhibits Ganglioside-Stimulated Lymphocyte Rosette Formation in Multiple Sclerosis
Authors: Davison Alan N. , Ilyas Amjad A.
Published: July 2009

Brain gangliosides have been found to stimulate active lymphocyte rosette formation in patients with multiple sclerosis during an active phase of the illness. On antigenic stimulation, a soluble factor is released which enhances active rosette formation. These reactions do not occur in multiple sclerosis patients during remission, in other neurological diseases or in controls that we have tested. More than one antigen may act on sensitized lymphocytes. The ganglioside-mediated response of lymphocytes from multiple sclerosis patients is blocked in vitro by Cyclosporin A.
Levels of T Lymphocytes, But Not Specific Antibodies, Reflect Clinical Presentation in Human Herpes Simplex Keratitis
Authors: Youinou P.Y. , Colin J.C. , Miossec P.
Published: July 2009

Total erythrocyte Rosette-forming cells (ERFC) have been found to be decreased in 44 patients with recurrent ocular herpes but normal in 26 patients with the primary form of the disease. Active ERFC have been found to be decreased in 27 patients with herpetic keratouveitis and normal in 43 patients with superficial herpetic keratitis. Antibodies to herpes simplex virus could not be used to distinguish the various clinical presentations of the disease.
Vascular Disease Burden and In-Hospital Outcomes Among Patients Undergoing Percutaneous Coronary Intervention in New York State
Authors: Berger Jeffrey S. , Petersen John L. , Brown David L.
Published: July 2009

Background—

The presence of atherosclerosis in extracardiac vascular beds is associated with an increased risk of adverse cardiovascular outcomes among stable patients with coronary artery disease (CAD). However, there is little data regarding the impact of the presence and extent of vascular disease on outcomes in patients with CAD undergoing percutaneous coronary intervention.

Methods and Results—

We analyzed 69 045 consecutive patients from the New York State Coronary Angioplasty Reporting System database who underwent percutaneous coronary intervention between 1998 and 1999. Vascular disease burden was assessed by history of aortoiliac, femoral-popliteal, and carotid disease. Patients were stratified into 3 groups: CAD alone, CAD and 1 additional site, and CAD and 2 or 3 additional sites. A logistic regression model was constructed to determine the relation between vascular disease burden and in-hospital mortality. Any history of vascular disease was present in 5915 (8.6%) of the population, of whom 4840 (82%) had CAD and 1 other disease location and 1075 (18%) had CAD and 2 or 3 other disease locations. There was a significant relationship between the number of disease locations and hospital mortality, ranging from 0.7% in patients with CAD alone to 2.0% and 2.6% for patients with 1 or ≥2 disease locations, respectively (
P
<0.001). In unadjusted analysis, in-hospital mortality was ≈3-fold higher (odds ratio, 2.89; 95% CI, 2.31 to 3.60;
P
<0.001) and 4-fold higher (odds ratio, 3.78; 95% CI, 2.57 to 5.56;
P
<0.001) for inpatients with CAD and additional vascular disease at 1 site and ≥2 sites, respectively. After multivariable adjustment, each additional vascular bed affected was associated with a 50% increase in in-hospital mortality (odds ratio, 1.50; 95% CI, 1.27 to 1.78;
P
<0.001).

Conclusions—

Among patients with CAD undergoing percutaneous coronary intervention, vascular disease burden is associated with higher rates of adverse events and is an independent predictor of in-hospital mortality.
Apolipoprotein E Genotype Is Related to Progression of White Matter Lesion Load
Authors: Godin Ophélia , Tzourio Christophe , Maillard Pauline , Alpérovitch Annick , Mazoyer Bernard , Dufouil Carole
Published: July 2009

Background and Purpose—

The relationship between white matter lesions (WMLs) and the apolipoprotein E genotype has been controversial from cross-sectional studies and no longitudinal finding has been reported. We investigated whether the apolipoprotein E genotype influences baseline and evolution over 4-year follow-up of WML volumes in a population-based sample of 1779 nondemented subjects aged 65 to 80 years old at enrollment.

Methods—

The sample consisted of 3C-Dijon study participants who had 2 cerebral MRIs, at entry and at 4-year follow-up. WML volumes were estimated using a fully automatic procedure. We performed analysis of covariance to evaluate the relationship between apolipoprotein E genotype and WML load and progression.

Results—

Multivariable analyses showed that ε4ε4 individuals had both significantly higher WML volume at baseline and higher WML increase over 4-year follow-up than noncarriers and heterozygous of the ε4 allele for apolipoprotein E genotype.

Conclusion—

These findings suggest it might be important to take into account WML severity when assessing the relationship between apolipoprotein E and dementia.
Lesion Patterns and Stroke Mechanisms in Concurrent Atherosclerosis of Intracranial and Extracranial Vessels
Authors: Man Bik Ling , Fu Yat Pang , Chan Yin Yan , Lam Wynnie , Hui Andrew Chi Fai , Leung Wai Hong , Mok Vincent , Wong Ka Sing
Published: July 2009

Background and Purpose—

Concurrent atherosclerosis of the intracranial and extracranial cerebrovascular system is common in Asians. The typical lesion patterns and the mechanisms of stroke in patients with concurrent stenoses are unclear. This study aimed to determine these stroke features of such patients in Hong Kong.

Methods—

We conducted a cross-sectional cohort study in a university hospital from January 2002 to December 2003. Consecutive Chinese patients with acute ischemic stroke underwent CT brain, MRI brain (with MR angiography and diffusion-weighted imaging sequences), and carotid duplex.

Results—

In total, 251 patients were included in the analysis. Of these, 109 (43%) had concurrent stenoses. Patients who had concurrent stenoses, as compared with those without concurrent stenoses, had more symptomatic stenoses (84% versus 58%; OR, 4.0; 95% CI, 2.1 to 7.3;
P
<0.001), more concomitant perforating artery infarct, pial infarct, and borderzone infarct (14% versus 4%; OR, 3.6; 95% CI, 1.4 to 9.7;
P
=0.007), more multiple diffusion-weighted imaging lesions (55% versus 37%; OR, 2.1; 95% CI, 1.3 to 3.4;
P
=0.005), and more infarcts in the territory of the leptomeningeal branches of middle cerebral artery (26% versus 13%; OR, 2.2; 95% CI, 1.2 to 4.3;
P
=0.01). In multivariate regression analysis, smoking; prior stroke; the presence of concomitant pial infarct, pial infarct, and borderzone infarcts; multiple diffusion-weighted imaging lesions; and symptomatic stenoses were significantly associated with concurrent stenoses. Among patients with concurrent stenoses, those who had tandem lesions, as compared with those who had nontandem lesions, had more perforating artery infarct and borderzone infarcts (27% versus 8%; OR, 4.3; 95% CI, 0.9 to 19.8;
P
=0.04); more concomitant pial infarct, pial infarct, and borderzone infarcts (18% versus 0%;
P
=0.02), and more multiple diffusion-weighted imaging lesions (65% versus 23%; OR, 6.2; 95% CI, 2.2 to 17.2;
P
<0.001). Infarcts in the territory of middle cerebral artery leptomeningeal branches and symptomatic stenoses were more common in patients with tandem lesions.

Conclusions—

Concomitant perforating artery infarct, pial infarct, and borderzone infarcts; multiple diffusion-weighted imaging lesions, and infarcts in the leptomeningeal branches of the middle cerebral artery were more common in patients with concurrent stenoses, especially those with tandem lesions. This study suggested that the combination of hemodynamic compromise attributable to concurrent stenoses and artery-to-artery embolization is a common stroke mechanism in these patients.
Hypoxic Preconditioning-Induced Cerebral Ischemic Tolerance
Authors: Wacker Bradley K. , Park Tae Sung , Gidday Jeffrey M.
Published: July 2009

Background and Purpose—

The importance of bioactive lipid signaling under physiological and pathophysiological conditions is progressively becoming recognized. The disparate distribution of sphingosine kinase (SphK) isoform activity in normal and ischemic brain, particularly the large excess of SphK2 in cerebral microvascular endothelial cells, suggests potentially unique cell- and region-specific signaling by its product sphingosine-1-phosphate. The present study sought to test the isoform-specific role of SphK as a trigger of hypoxic preconditioning (HPC)-induced ischemic tolerance.

Methods—

Temporal changes in microvascular SphK activity and expression were measured after HPC. The SphK inhibitor dimethylsphingosine or sphingosine analog FTY720 was administered to adult male Swiss-Webster ND4 mice before HPC. Two days later, mice underwent a 60-minute transient middle cerebral artery occlusion and at 24 hours of reperfusion, infarct volume, neurological deficit, and hemispheric edema were measured.

Results—

HPC rapidly increased microvascular SphK2 protein expression (1.7±0.2-fold) and activity (2.5±0.6-fold), peaking at 2 hours, whereas SphK1 was unchanged. SphK inhibition during HPC abrogated reductions in infarct volume, neurological deficit, and ipsilateral edema in HPC-treated mice. FTY720 given 48 hours before stroke also promoted ischemic tolerance; when combined with HPC, even greater (and dimethylsphingosine-reversible) protection was noted.

Conclusions—

These findings indicate hypoxia-sensitive increases in SphK2 activity may serve as a proximal trigger that ultimately leads to sphingosine-1-phosphate-mediated alterations in gene expression that promote the ischemia-tolerant phenotype. Thus, components of this bioactive lipid signaling pathway may be suitable therapeutic targets for protecting the neurovascular unit in stroke.
Building Utopia: Performance and the Fantasy of Urban Renewal in Contemporary Toronto
Authors: Levin Laura , Solga Kim
Published: July 2009

Toronto markets itself as a city in renewal, a “creative city” of the future full of arts and culture. Alongside the official pitch, a number of street-level underground initiatives reimagine Toronto's utopic future in a different way by means of site-specific performances.
Orbito-frontal Cortex is Necessary for Temporal Context Memory
Authors: Duarte Audrey , Henson Richard N. , Knight Robert T. , Emery Tina , Graham Kim S.
Published: July 2009

Lesion and neuroimaging studies suggest that orbito-frontal cortex (OFC) supports temporal aspects of episodic memory. However, it is unclear whether OFC contributes to the encoding and/or retrieval of temporal context and whether it is selective for temporal relative to nontemporal (spatial) context memory. We addressed this issue with two complimentary studies: functional magnetic resonance imaging to measure OFC activity associated with successful temporal and spatial context memory during encoding and retrieval in healthy young participants, and a neuropsychological investigation to measure changes in spatial and temporal context memory in OFC lesion patients. Imaging results revealed that OFC contributed to encoding and retrieval of associations between objects and their temporal but not their spatial contexts. Consistent with this, OFC patients exhibited impairments in temporal but not spatial source memory accuracy. These results suggest that OFC plays a critical role in the formation and subsequent retrieval of temporal context.
Influence of COMT Gene Polymorphism on fMRI-assessed Sustained and Transient Activity during a Working Memory Task
Authors: de Frias Cindy M. , Marklund Petter , Eriksson Elias , Larsson Anne , Öman Lena , Annerbrink Kristina , Bäckman Lars , Nilsson Lars-Göran , Nyberg Lars
Published: July 2009

The catechol O-methyltransferase (COMT) gene—encoding an enzyme that is essential for the degradation of dopamine (DA) in prefrontal cortex (PFC)—contains a single nucleotide polymorphism (val/met) important for cognition. According to the tonic–phasic hypothesis, individuals carrying the low-enzyme-activity allele (met) are characterized by enhanced tonic DA activity in PFC, promoting sustained cognitive representations in working memory. Val carriers have reduced tonic but enhanced phasic dopaminergic activity in subcortical regions, enhancing cognitive flexibility. We tested the tonic–phasic DA hypothesis by dissociating sustained and transient brain activity during performance on a 2-back working memory test using mixed blocked/event-related functional magnetic resonance imaging. Participants were men recruited from a random sample of the population (the Betula study) and consisted of 11 met/met and 11 val/val carriers aged 50 to 65 years, matched on age, education, and cognitive performance. There were no differences in 2-back performance between genotype groups. Met carriers displayed a greater transient medial temporal lobe response in the updating phase of working memory, whereas val carriers showed a greater sustained PFC activation in the maintenance phase. These results support the tonic–phasic theory of DA function in elucidating the specific phenotypic influence of the COMT val158met polymorphism on different components of working memory.
New York City Storm Surges: Climatology and an Analysis of the Wind and Cyclone Evolution
Authors: Colle Brian A. , Rojowsky Katherine , Buonaito Frank
Published: July 2009

A climatological description (“climatology”) of storm surges and actual flooding (storm tide) events from 1959 to 2007 is presented for the New York City (NYC) harbor. The prevailing meteorological conditions associated with these surges are also highlighted. Two surge thresholds of 0.6–1.0 m and >1.0 m were used at the Battery, New York (south side of Manhattan in NYC), to identify minor and moderate events, respectively. The minor-surge threshold combined with a tide at or above mean high water (MHW) favors a coastal flood advisory for NYC, and the moderate surge above MHW leads to a coastal flood warning. The number of minor surges has decreased gradually during the last several decades at NYC while the number of minor (storm tide) flooding events has increased slightly given the gradual rise in sea level. There were no moderate flooding events at the Battery from 1997 to 2007, which is the quietest period during the last 50 yr. However, if sea level rises 12–50 cm during the next century, the number of moderate flooding events is likely to increase exponentially. Using cyclone tracking and compositing of the NCEP global reanalysis (before 1979) and regional reanalysis (after 1978) data, the mean synoptic evolution was obtained for the NYC surge events. There are a variety of storm tracks associated with minor surges, whereas moderate surges favor a cyclone tracking northward along the East Coast. The average surface winds at NYC veer from northwesterly at 48 h before the time of maximum surge to a persistent period of east-northeasterlies beginning about 24 h before the surge. There is a relatively large variance in wind directions and speeds around the time of maximum surge, thus suggesting the importance of other factors (fetch, storm duration and track, etc.).
Validation of the CERES Edition 2B Surface-Only Flux Algorithms
Authors: Kratz David P. , Gupta Shashi K. , Wilber Anne C. , Sothcott Victor E.
Published: July 2009

The Clouds and the Earth’s Radiant Energy System (CERES) project uses two shortwave (SW) and two longwave (LW) algorithms to derive surface radiative fluxes on an instantaneous footprint basis from a combination of top-of-atmosphere fluxes, ancillary meteorological data, and retrieved cloud properties. Since the CERES project examines the radiative forcings and feedbacks for Earth’s entire climate system, validation of these models for a wide variety of surface conditions is paramount. The present validation effort focuses upon the ability of these surface-only flux algorithms to produce accurate CERES Edition 2B single scanner footprint data from the Terra and Aqua spacecraft measurements. To facilitate the validation process, high-quality radiometric surface observations have been acquired that were coincident with the CERES-derived surface fluxes. For both SW models, systematic errors range from −20 to −12 W m−2 (from −2.8% to −1.6%) for global clear-sky cases, while for the all-sky SW model, the systematic errors range from 14 to 21 W m−2 (3.2%–4.8%) for global cloudy-sky cases. Larger systematic errors were seen for the individual surface types, and significant random errors where observed, especially for cloudy-sky cases. While the SW models nearly achieved the 20 W m−2 accuracy requirements established for climate research, further improvements are warranted. For the clear-sky LW model, systematic errors were observed to fall within ±5.4 W m−2 (±1.9%) except for the polar case in which systematic errors on the order from −15 to −11 W m−2 (from −13% to −7.2%) occurred. For the all-sky LW model, systematic errors were less than ±9.2 W m−2 (±7.6%) for both the clear-sky and cloudy-sky cases. The random errors were less than 17 W m−2 (6.2%) for clear-sky cases and 28 W m−2 (13%) for cloudy-sky cases, except for the desert cases in which very high surface skin temperatures caused an overestimation in the model-calculated surface fluxes. Overall, however, the LW models met the accuracy requirements for climate research.
Homogeneous and Inhomogeneous Mixing in Cumulus Clouds: Dependence on Local Turbulence Structure
Authors: Lehmann Katrin , Siebert Holger , Shaw Raymond A.
Published: July 2009

The helicopter-borne instrument payload known as the Airborne Cloud Turbulence Observation System (ACTOS) was used to study the entrainment and mixing processes in shallow warm cumulus clouds. The characteristics of the mixing process are determined by the Damköhler number, defined as the ratio of the mixing and a thermodynamic reaction time scale. The definition of the reaction time scale is refined by investigating the relationship between the droplet evaporation time and the phase relaxation time. Following arguments of classical turbulence theory, it is concluded that the description of the mixing process through a single Damköhler number is not sufficient and instead the concept of a transition length scale is introduced. The transition length scale separates the inertial subrange into a range of length scales for which mixing between ambient dry and cloudy air is inhomogeneous, and a range for which the mixing is homogeneous. The new concept is tested on the ACTOS dataset. The effect of entrained subsaturated air on the droplet number size distribution is analyzed using mixing diagrams correlating droplet number concentration and droplet size. The data suggest that homogeneous mixing is more likely to occur in the vicinity of the cloud core, whereas inhomogeneous mixing dominates in more diluted cloud regions. Paluch diagrams are used to support this hypothesis. The observations suggest that homogeneous mixing is favored when the transition length scale exceeds approximately 10 cm. Evidence was found that suggests that under certain conditions mixing can lead to enhanced droplet growth such that the largest droplets are found in the most diluted cloud regions.
Spatial and Temporal Scales of Boundary Layer Wind Predictability in Response to Small-Amplitude Land Surface Uncertainty
Authors: Hacker Joshua P.
Published: July 2009

Predictability experiments with the Weather Research and Forecast (WRF) model as a proxy for the atmosphere are analyzed to quantify the spatial and temporal scales of boundary layer wind response to land surface perturbations. Soil moisture is chosen as the land surface variable subject to uncertainty because the atmosphere is known to be sensitive to its state. A range of experiments with spatially correlated, small-amplitude perturbations to soil moisture leads to results that show the dependence of predictability on atmospheric conditions. The primary conclusions are as follows: 1) atmospheric conditions, including static instability and the presence of deep convection, determine whether large errors and local loss of predictability are possible in response to soil moisture errors; 2) the scale of soil moisture uncertainty determines scales of PBL wind predictability when the atmosphere is resistant to upscale error transfer, but when the atmosphere is sensitive the scale and magnitude of soil moisture uncertainty are not important after a few hours; and 3) nonlinear error growth is present whether or not the atmosphere is relatively sensitive to soil moisture uncertainty, leading to doubling times of minutes to hours for finite-sized perturbations. Similar results could be expected from other land surface variables or parameters that exert time-dependent forcing on the atmosphere that is similar in magnitude and scale to that of soil moisture.
Understanding the Characteristics of Daily Precipitation over the United States Using the North American Regional Reanalysis
Authors: Becker Emily J. , Berbery Ernesto Hugo , Higgins R. Wayne
Published: July 2009

This study examines the seasonal characteristics of daily precipitation over the United States using the North American Regional Reanalysis (NARR). To help understand the physical mechanisms that contribute to changes in the characteristics of daily precipitation, vertically integrated moisture flux convergence (MFC) and precipitable water were included in the study. First, an analysis of the NARR precipitation was carried out because while observed precipitation is indirectly assimilated in the system, differences exist. The NARR mean seasonal amount is very close to that of observations throughout the year, although NARR exhibits a slight systematic bias toward more-frequent, lighter precipitation. Particularly during summer, the precipitation intensity and the probability distribution function (PDF) indicate that NARR somewhat underestimates extremes and overestimates lighter events in the eastern half of the United States. The intensity and PDF of moisture flux convergence exhibit a strong similarity to those of precipitation, suggesting a link between strong MFC and precipitation extremes. On the other hand, the relationship between the precipitable water and precipitation PDFs is weaker, based on the lack of agreement of their gamma distribution parameters.

The dependence of the precipitation PDF on the lower-frequency modulation of ENSO was examined. During El Niño winters, the Southwest and central United States, Gulf of Mexico region, and southeastern coast have greater precipitation intensity and extremes than during La Niña, and the Ohio River and Red River basins have lower intensity and fewer extreme events. During summer, the northern Rocky Mountains receive higher intensity precipitation with more extreme events. Most areas where the change in the daily mean precipitation between ENSO phases is large have greater shifts in the extreme tail of the PDF. The ENSO-related response of moisture flux convergence is similar to that of precipitation. ENSO-related shifts in the precipitation PDF do not appear to have a strong relationship to the shifts in precipitable water.
Temperature Trend Patterns in Southern Hemisphere High Latitudes: Novel Indicators of Stratospheric Change
Authors: Lin Pu , Fu Qiang , Solomon Susan , Wallace John M.
Published: July 2009

Robust stratospheric temperature trend patterns are suggested in the winter and spring seasons in the Southern Hemisphere high latitudes from the satellite-borne Microwave Sounding Unit (MSU) measurement for 1979–2007. These patterns serve as indicators of key processes governing temperature and ozone changes in the Antarctic. The observed patterns are characterized by cooling and warming regions of comparable magnitudes, with the strongest local trends occurring in September and October. In September, ozone depletion induces radiative cooling, and strengthening of the Brewer–Dobson circulation (BDC) induces dynamical warming. Because the trends induced by these two processes are centered in different locations in September, they do not cancel each other, but rather produce a wavelike structure. In contrast, during October, the ozone-induced radiative cooling and the BDC-induced warming exhibit a more zonally symmetric structure than in September, and hence largely cancel each other. However, the October quasi-stationary planetary wavenumber 1 has shifted eastward from 1979 to 2007, producing a zonal wavenumber-1 trend structure, which dominates the observed temperature trend pattern.

Simulated temperature changes for 1979–2007 from coupled atmosphere–ocean general circulation model (AOGCM) experiments run for the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) are compared with the observations. In general, the simulated temperature changes are dominated by zonally symmetric ozone-induced radiative cooling. The models fail to simulate the warming in the southern polar stratosphere, implying a lack of the BDC strengthening in these models. They also fail to simulate the quasi-stationary planetary wave changes observed in October and November.
Influence of Lateral Advection on Residual Currents in Microtidal Estuaries
Authors: Cheng Peng , Valle-Levinson Arnoldo
Published: July 2009

The influence of nonlinear lateral advection on estuarine exchange flow is examined with a scaling analysis and eight groups of idealized numerical experiments. Nonlinear lateral advection is related to the linkage between lateral circulation and the lateral shear of the along-estuary flow. The relative contribution of lateral advection to the overall dynamics of a microtidal estuary is found to be a function of width and depth, and of vertical mixing. Lateral advection is dynamically important in narrow and deep estuaries, particularly under relatively weak vertical mixing. The relative importance of lateral advection and the earth’s rotation on estuarine dynamics can be evaluated in terms of the nondimensional Rossby and Ekman numbers (Ro and Ek). Lateral advection is most effective at large Ro and small Ek and is negligible at small Ro and large Ek. As expected, the earth’s rotation is most significant at small Ro and Ek, and is negligible at large Ro and Ek. Under the influence of lateral advection and the earth’s rotation, the lateral structure of estuarine exchange flows is a function of Ro and Ek. In some instances, the exchange flow is vertically sheared and in others it is laterally sheared. Classical estuarine dynamics, which yields vertically sheared exchange flows, occurs at intermediate Ro and large Ek. The main role of lateral advection is to reduce lateral variability of estuarine exchange flow and generate a vertically sheared, two-layer exchange flow structure.
Weather Radar Ground Clutter. Part I: Identification, Modeling, and Simulation
Authors: Hubbert J. C. , Dixon M. , Ellis S. M. , Meymaris G.
Published: July 2009

Real-time ground-clutter identification and subsequent filtering of clutter-contaminated data is addressed in this two-part paper. Part I focuses on the identification, modeling, and simulation of S-band ground-clutter echo. A new clutter identification parameter, clutter phase alignment (CPA), is presented. CPA is a measure primarily of the phase variability of the in-phase and quadrature-phase time series samples for a given radar resolution volume. CPA is also a function of amplitude variability of the time series. It is shown that CPA is an excellent discriminator of ground clutter versus precipitation echoes. A typically used weather model, time series simulator is shown to inadequately describe experimentally observed CPA. Thus, a new technique for the simulation of ground-clutter echo is developed that better predicts the experimentally observed CPA. Experimental data from the Denver Next Generation Weather Radar (NEXRAD) at the Denver, Colorado, Front Range Airport (KFTG), and NCAR’s S-band dual-polarization Doppler radar (S-Pol) are used to illustrate CPA. In Part II, CPA is used in a fuzzy logic algorithm for improved clutter identification.
Weather Radar Ground Clutter. Part II: Real-Time Identification and Filtering
Authors: Hubbert J. C. , Dixon M. , Ellis S. M.
Published: July 2009

The identification and mitigation of anomalous propagation (AP) and normal propagation (NP) ground clutter is an ongoing problem in radar meteorology. Scatter from ground-clutter targets routinely contaminates radar data and masks weather returns causing poor data quality. The problem is typically mitigated by applying a clutter filter to all radar data, but this also biases weather data at near-zero velocity. Modern radar processors make possible the real-time identification and filtering of AP clutter. A fuzzy logic algorithm is used to distinguish between clutter echoes and precipitation echoes and, subsequently, a clutter filter is applied to those radar resolution volumes where clutter is present. In this way, zero-velocity weather echoes are preserved while clutter echoes are mitigated. Since the radar moments are recalculated from clutter-filtered echoes, the underlying weather echo signatures are revealed, thereby significantly increasing the visibility of weather echo. This paper describes the fuzzy logic algorithm, clutter mitigation decision (CMD), for clutter echo identification. A new feature field, clutter phase alignment (CPA), is introduced and described. A detailed discussion of CPA is given in Part I of this paper. The CMD algorithm is illustrated with experimental data from the Denver Next Generation Weather Radar (NEXRAD) at the Denver, Colorado, Front Range Airport (KFTG); and NCAR’s S-band dual-polarization Doppler radar (S-Pol).
Measurements of Sea Surface Height Variability in the Eastern South Atlantic from Pressure Sensor–Equipped Inverted Echo Sounders: Baroclinic and Barotropic Components
Authors: Baker-Yeboah Sheekela , Watts D. Randolph , Byrne Deirdre A.
Published: July 2009

Variability in sea surface height (SSH) can be decomposed into two contributions: one from changes in mass in the water column (barotropic) and the other from purely steric changes (baroclinic). Both contributions can be determined from data recorded by a pressure sensor–equipped inverted echo sounder (PIES). PIES data from the Agulhas South Atlantic Thermohaline Experiment (ASTTEX) were used, collected in the Cape Basin off South Africa, along 1000 km of an eddy corridor where Agulhas eddies carry cores of warm, salty Indian Ocean waters into the South Atlantic. The paper presents in detail the method used to convert PIES measurements into barotropic, baroclinic, and total SSH, and discusses the error budget. The baroclinic contribution is geopotential height (reference 4500 dbar), which can be determined from the measured vertical acoustic travel time together with a lookup curve based on the regional hydrography. The main error source is scatter about this curve that depends on the extent to which water masses advecting along each geopotential streamline may derive from different ocean regions. The barotropic contribution can be determined from the bottom pressure measurements of the mass variation in the water column and has an uncertainty due to sensor calibration drift in two years corresponding to 1-cm water column height. The barotropic component accounts for 20% of the overall SSH variance and 47% during large signal intervals exceeding 15 cm. PIES data demonstrate via the two measurements that barotropic and baroclinic contributions may work independently or in concert in different mesoscale eddies. The combined structure need not be equivalent barotropic. In particular, deep barotropic eddies exhibit mesoscale spatiotemporal scales and may or may not be systematically tilted or aligned in space or time relative to baroclinic eddies.
Remote Real-Time Video-Enabled Docking for Underwater Autonomous Platforms
Authors: Moline Mark A. , Schofield Oscar
Published: July 2009

One of the key challenges in the development and implementation of ocean observatories is sustained observations over relevant temporal and spatial scales. Autonomous underwater vehicles (AUVs) have demonstrated their potential for synoptic spatial coverage of regions of scientific and strategic interest. The range and duration of these systems are limited, however, to the capabilities of a single charge. A few efforts have been made to develop docking systems for propeller-driven vehicles; however, these systems are not applicable for buoyancy-driven gliders and cannot be universally applied to AUVs. Here the authors introduce an alternative strategy for AUV docking, demonstrate feasibility with a series of field tests using a remotely operated vehicle (ROV) to remotely recover an AUV, and comment on the scalability within the framework of the evolving global ocean observatory initiatives. Implementation of simple strategies such as this has the potential to reduce the chronic problem of undersampling in the ocean and may facilitate addressing some outstanding scientific questions related to the ocean.
Comparing Strategic Voting Under FPTP and PR
Authors: Abramson Paul R. , Aldrich John H. , Blais André , Diamond Matthew , Diskin Abraham , Indridason Indridi H. , Lee Daniel J. , Levine Renan
Published: July 2009

Based on recent work that suggests that voters in proportional representation (PR) systems have incentives to cast strategic votes, the authors hypothesize that levels of strategic voting are similar in both first-past-the-post (FPTP) and PR systems. Comparing vote intentions in majoritarian elections in the United States, Mexico, Britain, and Israel to PR elections in Israel and the Netherlands, the authors find that a substantial proportion of the voters desert their most preferred candidate or party and that patterns of strategic voting across FPTP and PR bear striking similarities. In every election, smaller parties tend to lose votes to major parties. Because there tend to be more small parties in PR systems, tactical voting is actually more common under PR than under FPTP. The findings suggest that whatever the electoral system, voters focus on the policy consequences of their behavior and which parties are likely to influence policy outcomes following the election.
Production of Metal Wire — Polymeric Foam Composites for Dielectric Applications
Authors: Colton Jonathan , Blandin Christopher
Published: July 2009

Dielectric materials are used as spacers in antennas. The design of the dielectric determines the properties of the antenna. The insertion of high dielectric materials in a specific pattern into a low dielectric matrix material is one means to accomplish this. This article reports on the insertion of metal cylinders (wire or nails) into polymer foams to produce such a material. Depending upon the antenna properties desired, the patterns and number of nails vary tremendously. Varying the depths of the nails into the antenna spacers is also important. A penetration model was developed that calculates the forces required to penetrate a nail into foam. Experimental observations are used to verify the model. These equations allow one to predict the forces required for a nail to be inserted into foam to a desired depth, thereby facilitating manufacture of these dielectric materials.
Prediction of Long-term Creep of Composites from Doubly-shifted Polymer Creep Data
Authors: Barbero Ever J.
Published: July 2009

Environmental effects on the creep response of composites are of great interest because these materials are very sensitive to temperature and other environmental conditions. Short and long-term creep effects have been studied for composites under various environmental conditions, but most studies rely on experimental testing of particular laminates. Here, a novel micro-mechanical/laminate model is developed to predict the creep response of laminated polymer matrix composites from matrix creep data. Furthermore, a novel two-parameter superposition method is used to predict the long-term response of the polymer matrix as a function of two environmental parameters: moisture and temperature. The procedure used to compute the two shift factors is described. The resulting master curve can be used to predict the long-term properties of the matrix and for any temperature and humidity conditions. Once the matrix behavior is known, the micro-mechanical/ laminate model allows for accurate prediction of long-term properties of arbitrary laminates for the same conditions.
Multiple Injection Ports and Part Thickness Impact on Wetout of High Pull Speed Resin Injection Pultrusion
Authors: Jeswani A.L. , Roux J.A. , Vaughan J.G.
Published: July 2009

Manufacturing of composite materials using resin injection pultrusion is presently a cost-effective method of producing composites; however, there is still a potential for significant improvements in the productivity of this approach for high-speed production. Complete wetout of the dry fiber reinforcement by the liquid resin at high pull speeds is essential for improving the throughput of the pultrusion process. Complete fiber reinforcement wetout depends strongly on axial placement of the injection ports/slots and the geometry of the injection chamber (taper of the walls of injection chamber and final part thickness). Geometric parameters modeled in this study were multiple injection ports and their axial location within the injection chamber and thickness of the final pultruded part; investigations of these geometric parameters are original contributions of the work. In this study, the finite volume numerical technique was employed to model the flow of polyester resin through the glass fiber reinforcement. Results depict the impact of varying the thickness of the pultruded part and the use of multiple injection ports on the minimum injection pressure necessary to achieve complete fiber matrix wetout and on the resin pressure at the injection chamber exit for the slot injection and for the discrete port injection configurations. This model is a useful guide for improving the efficiency and productivity of the resin injection pultrusion process for an attached injection chamber configuration with tapered walls.
The Investigation on the influence of DMDHEU on the Wrinkle and Abrasion Resistance of Cotton Fabrics using Image Processing
Authors: Naderpour F. , Mirjalili S.A. , Sharzehee M.
Published: July 2009

In this paper, the application of image analysis to assess the fabric wrinkle and abrasion resistance in order to compare with experimental methods is described. Three samples of cotton fabrics (plain) with different finishing treatments were tested. In the present work, employing an appropriate lighting method, sample images were captured by scanner, and then images prepared from samples were processed in MATLAB. Finally, the number which evaluates each mentioned property was achieved. The results compare wrinkle and abrasion with experimental evaluation, revealing that data from image analysis is more precise than experimental data.
School Psychologists’ Role in School
Authors: Mägi Katrin , Kikas Eve
Published: July 2009

The aim of the present study was to investigate the expectations and evaluations of Estonian school principals on the work of school psychologists. Surveys have shown that teachers and school principals value traditional assessment activities but also desire more consultation. School psychologists emphasize the importance of system counselling, but in practice it can seldom be seen. One of the obstacles to the change of school psychologists’ roles might be the expectations of school principals. Therefore, school principals were questioned regarding these issues. One hundred and seven principals participated in the study. In addition, interviews were carried out with three school principals. The results showed that the most desired services by Estonian school principals are individual counselling of children and consultation with teachers and parents. System counselling is expected less frequently, but no strong resistance to it was found. It seems that school principals do not desire it because they are not yet aware of its possibilities.