bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Quantum Cascade Laser–Based Reflectometer for On-Orbit Blackbody Cavity Monitoring
Authors: Gero P. Jonathan , Dykema John A. , Anderson James G. 
Published: April 2009

Abstract
Satellite measurements pinned to international standards are needed to monitor the earth’s climate, quantify human influence thereon, and test forecasts of future climate change. Credible observations require that measurement uncertainties be evaluated on orbit during a mission’s operational lifetime. The most accurate spaceborne measurements of thermal infrared radiance are achieved with blackbody calibration. The physical properties of blackbody cavity surface coatings are known to change upon extended exposure to the low earth orbit environment. Any such drift must be quantified to continue correctly calibrating observed radiance on orbit. A method is presented to diagnose the effective emissivity of a blackbody cavity in situ using a quantum cascade laser (QCL)-based reflectometer. QCLs provide high-power single-mode output in the thermal infrared and have small mechanical footprints that facilitate integration into existing optical systems. The laser reflectivity in a test blackbody cavity was measured to be 9.22 × 10−4 with an uncertainty of 8.9 × 10−5, which is equivalent to a detection limit of 3 mK in the error in radiance temperature for a calibration blackbody (at 330 K and 1000 cm−1) resulting from cavity emissivity drift. These results provide the experimental foundation for this technology to be implemented on satellite instruments and thus eliminate a key time-dependent systematic error from future measurements on orbit.
Semiautonomous FTS Observation System for Remote Sensing of Stratospheric and Tropospheric Gases
Authors: Hannigan James W. , Coffey Michael T. , Goldman Aaron 
Published: April 2009

Abstract
A solar-viewing Fourier transform spectrometer (FTS) at Thule, Greenland (76.5°N, 68.8°W, 225 m MSL), has been in operation as part of the Network for the Detection of Atmospheric Composition Change [NDACC; formerly the Network for the Detection of Stratospheric Change (NDSC)] since 1999. Observations have been made, on average, 77 days yr−1 during the 8 months, excluding polar night. The semiautonomous operation of the instrument, including its associated optical, cryogenic, and control systems, is of primary importance to acquiring long-term data records efficiently and is herein described. Discussed in this paper are the data processing and spectra analysis methodology that are used to convert the measured interferograms into geophysical data products. Vertical profile retrievals derived from the high-resolution solar absorption spectra use the optimal estimation method. Total column amounts then represent the integration of these vertical profiles. As an example of this process, results are presented for daily average total column amounts of HF, HCl, ClONO2, and CCl2F2 from 2001 through 2007. The means of unperturbed summertime observations are used in a preliminary study of their annual trends.
The Impact of Lightning Data Assimilation on a Winter Storm Simulation over the North Pacific Ocean
Authors: Pessi Antti T. , Businger Steven 
Published: April 2009

Abstract
In this paper, the potential of lightning data assimilation to improve NWP forecasts over data-sparse oceans is investigated using, for the first time, a continuous, calibrated lightning data stream. The lightning data employed in this study are from the Pacific Lightning Detection Network/Long-Range Lightning Detection Network (PacNet/LLDN), which has been calibrated for detection efficiency and location accuracy. The method utilizes an empirical lightning–convective rainfall relationship, derived specifically from North Pacific winter storms observed by PacNet/LLDN. The assimilation method nudges the model’s latent heating rates according to rainfall estimates derived from PacNet/LLDN lightning observations. The experiment was designed to be employed in an operational setting. To illustrate the promise of the approach, lightning data from a notable extratropical storm that occurred over the northeast Pacific Ocean in late December 2002 were assimilated into the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5). The storm exhibited a very electrically active cold front with most of the lightning observed 300–1200 km away from the storm center. The storm deepened rapidly (12 hPa in 12 h) and was poorly forecast by the operational models. The assimilation of lightning data generally improved the pressure and wind forecasts, as the validation of the model results using available surface and satellite data revealed. An analysis is presented to illustrate the impact of assimilation of frontal lightning on the storm development and dynamics. The links among deep convection, thermal wind along the front, and cyclogenesis are explicitly explored.
Chemical Source Inversion Using Assimilated Constituent Observations in an Idealized Two-Dimensional System
Authors: Tangborn Andrew , Cooper Robert , Pawson Steven , Sun Zhibin 
Published: April 2009

Abstract
A source inversion technique for chemical constituents is presented that uses assimilated constituent observations rather than directly using the observations. The method is tested with a simple model problem, which is a two-dimensional Fourier–Galerkin transport model combined with a Kalman filter for data assimilation. Inversion is carried out using a Green’s function method and observations are simulated from a true state with added Gaussian noise. The forecast state uses the same spectral model but differs by an unbiased Gaussian model error and emissions models with constant errors. The numerical experiments employ both simulated in situ and satellite observation networks. Source inversion was carried out either by directly using synthetically generated observations with added noise or by first assimilating the observations and using the analyses to extract observations. Twenty identical twin experiments were conducted for each set of source and observation configurations, and it was found that in the limiting cases of a very few localized observations or an extremely large observation network there is little advantage to carrying out assimilation first. For intermediate observation densities, the source inversion error standard deviation is decreased by 50% to 90% when the observations are assimilated with the Kalman filter before carrying out the Green’s function inversion.
Effect of the Andes Cordillera on Precipitation from a Midlatitude Cold Front
Authors: Barrett Bradford S. , Garreaud RenéD. , Falvey Mark 
Published: April 2009

Abstract
The effects of the Andes Cordillera, the major mountain range in South America, on precipitation patterns of baroclinic systems approaching from the southeast Pacific remain largely unstudied. This study focuses on a case in late May 2008 when an upper-level trough and surface cold front produced widespread precipitation in central Chile. The primary goal was to analyze the physical mechanisms responsible for the structure and evolution of the precipitation.
Weather Research and Forecasting (WRF) model simulations indicate that as an upper-level trough approached central Chile, midtropospheric flow below 700 hPa was blocked by the high topography and deflected poleward in the form of a barrier jet. This northerly jet had wind maxima in excess of 15 m s−1, was centered around 925 hPa, and extended westward 200 km from the mountains. It intersected the cold front, which approached from the south near the coast, thereby increasing convergence along the frontal surface, slowing its equatorward progress, and enhancing rainfall over central Chile. Another separate region of heavy precipitation formed over the upwind slopes of the cordillera. A trajectory analysis confirmed that the barrier jet moved low-level parcels from their origin in the moist southeast Pacific boundary layer to the coast. When model topography was reduced to twenty percent of its original height, the cold front advanced more rapidly to the northeast, generated less precipitation in central Chile between 33° and 36°S, and produced minimal orographic precipitation on the upwind Andean slopes. Based on these findings, the high topography appears responsible for not only orographic precipitation but also for substantially increasing precipitation totals over the central coast and valley.
Difficulties with Correcting Radar Rainfall Estimates Based on Rain Gauge Data: A Case Study of Severe Weather in Montana on 16–17 June 2007
Authors: Vasiloff Steven V. , Howard Kenneth W. , Zhang Jian 
Published: April 2009

Abstract
The principal source of information for operational flash flood monitoring and warning issuance is weather radar–based quantitative estimates of precipitation. Rain gauges are considered truth for the purposes of validating and calibrating real-time radar-derived precipitation data, both in a real-time sense and climatologically. This paper examines various uncertainties and challenges involved with using radar and rain gauge data in a severe local storm environment. A series of severe thunderstorm systems that occurred across northeastern Montana illustrates various problems with comparing radar precipitation estimates and real-time gauge data, including extreme wind effects, hail, missing gauge data, and radar quality control. Ten radar–gauge time series pairs were analyzed with most found to be not useful for real-time radar calibration. These issues must be carefully considered within the context of ongoing efforts to develop robust real-time tools for evaluating radar–gauge uncertainties. Recommendations are made for radar and gauge data quality control efforts that would benefit the operational use of gauge data.
Skill of a Ceiling and Visibility Local Ensemble Prediction System (LEPS) according to Fog-Type Prediction at Paris-Charles de Gaulle Airport
Authors: Roquelaure Stevie , Tardif Robert , Remy Samuel , Bergot Thierry 
Published: April 2009

Abstract
A specific event, called a low-visibility procedure (LVP), has been defined when visibility is under 600 m and/or the ceiling is under 60 m at Paris-Charles de Gaulle Airport, Paris, France, to ensure air traffic safety and to reduce the economic issues related to poor visibility conditions. The Local Ensemble Prediction System (LEPS) has been designed to estimate LVP likelihood in order to help forecasters in their tasks. This work evaluates the skill of LEPS for each type of LVP that takes place at the airport area during five winter seasons from 2002 to 2007. An event-based classification reveals that stratus base lowering, advection, and radiation fogs make up for 78% of the LVP cases that occurred near the airport during this period. This study also demonstrates that LEPS is skillful on these types of event for short-term forecasts. When the ensemble runs start with initialized LVP events, the prediction of advection fogs is as skillful as the prediction of radiation fog events and stratus base lowering. At 3 and 6 h before the runs where LVP events were initialized, LEPS still shows positive skill for radiation fog events and stratus base lowering cases.
Marx and `Modernization'
Authors: Garrett Paul Michael 
Published: April 2009

• Summary: Despite the marginalization of Marxism with social work, Karl Marx's Capital still provides a devastating critique of capitalism and remains a vital resource for social workers seeking to understand and develop strategies of resistance to neoliberalization. • Findings: Marx provides a number of `reminders' or `coordinates' which might help us to make sense of transformations taking place within the `world of work' today. More fundamentally, he illuminates aspects of `actually existing capitalism'. Furthermore, focusing on the first volume of Capital helps us to think about a constellation of connected factors, loosely referred to under the headings of time, toil (or labour) and technology, underpinning the `modernization' of social work and related areas of activity. The book also remains important because it reminds contemporary readers that capitalism is an exploitative economic system which damages bodies and minds. In this context, it is significant that Marx was perturbed and outraged by how the lives of children were being destroyed by the dynamic, unregulated power of capital. • Applications : It would be erroneous to assume we can mechanically apply Marx's work in manifestly different times and circumstances. Rather, we have to `do our own work', in our particular time, place, and professional field and ponder whether some of the ideas adumbrated by Marx, in the late 19th century, still have contemporary resonance and meaning within neoliberal modernity.
Regulation of T cell-dendritic cell interactions by IL-7 governs T-cell activation and homeostasis
Authors: Saini Manoj , Pearson Claire , Seddon Benedict 
Published: April 2009

AbstractInterleukin-7 (IL-7) plays a central role in the homeostasis of the T-cell compartment by regulating T-cell survival and proliferation. Whether IL-7 can influence T-cell receptor (TCR) signaling in T cells remains controversial. Here, using IL-7–deficient hosts and TCR-transgenic T cells that conditionally express IL-7R, we examined antigen-specific T-cell responses in vitro and in vivo to viral infection and lymphopenia to determine whether IL-7 signaling influences TCR-triggered cell division events. In vitro, we could find no evidence that IL-7 signaling could costimulate T-cell activation over a broad range of conditions, suggesting that IL-7 does not directly tune TCR signaling. In vivo, however, we found an acute requirement for IL-7 signaling for efficiently triggering T-cell responses to influenza A virus challenge. Furthermore, we found that IL-7 was required for the enhanced homeostatic TCR signaling that drives lymphopenia-induced proliferation by a mechanism involving efficient contacts of T cells with dendritic cells. Consistent with this, saturating antigen-presenting capacity in vivo overcame the triggering defect in response to cognate peptide. Thus, we demonstrate a novel role for IL-7 in regulating T cell–dendritic cell interactions that is essential for both T-cell homeostasis and activation in vivo.
Altered cellular dynamics and endosteal location of aged early hematopoietic progenitor cells revealed by time-lapse intravital imaging in long bones
Authors: Köhler Anja , Schmithorst Vince , Filippi Marie-Dominique , Ryan Marnie A. , Daria Deidre , Gunzer Matthias , Geiger Hartmut 
Published: April 2009

AbstractAged hematopoietic stem cells (HSCs) are impaired in supporting hematopoiesis. The molecular and cellular mechanisms of stem cell aging are not well defined. HSCs interact with nonhematopoietic stroma cells in the bone marrow forming the niche. Interactions of hematopoietic cells with the stroma/microenvironment inside bone cavities are central to hematopoiesis as they regulate cell proliferation, self-renewal, and differentiation. We recently hypothesized that one underlying cause of altered hematopoiesis in aging might be due to altered interactions of aged stem cells with the microenvironment/niche. We developed time-lapse 2-photon microscopy and novel image analysis algorithms to quantify the dynamics of young and aged hematopoietic cells inside the marrow of long bones of mice in vivo. We report in this study that aged early hematopoietic progenitor cells (eHPCs) present with increased cell protrusion movement in vivo and localize more distantly to the endosteum compared with young eHPCs. This correlated with reduced adhesion to stroma cells as well as reduced cell polarity upon adhesion of aged eHPCs. These data support a role of altered eHPC dynamics and altered cell polarity, and thus altered niche biology in mechanisms of mammalian aging.
Comparison of the rates of joint arthroplasty in patients with severe factor VIII and IX deficiency: an index of different clinical severity of the 2 coagulation disorders
Authors: Tagariello Giuseppe , Iorio Alfonso , Santagostino Elena , Morfini Massimo , Bisson Ruggero , Innocenti Massimo , Mancuso Maria Elisa , Mazzucconi Maria Gabriella , Pasta Gian Luigi , Radossi Paolo , Rodorigo Giuseppina , Santoro Cristina , Sartori Roberto , Scaraggi Antonio , Solimeno Luigi Pier , Mannucci Pier Mannuccio 
Published: April 2009

AbstractData from the Italian Hemophilia Centres were collected to perform a retrospective survey of joint arthroplasty in patients with severe hemophilia. Twenty-nine of 49 hemophilia centers reported that 328 of the 347 operations were carried out in 253 patients with severe hemophilia A (HA) and 19 in 15 patients with severe hemophilia B (HB). When results were normalized to the whole Italian hemophilia population (1770 severe HA and 319 severe HB), patients with HA had a 3-fold higher risk of undergoing joint arthroplasty (odds ratio [OR], 3.38; 95% confidence interval [CI], 1.97-5.77; P < .001). These results were confirmed after adjustment for age, HIV, hepatitis C virus (HCV), and inhibitor in a Cox regression model (HR, 2.65; 95% CI, 1.62-4.33; P < .001). The survival analysis of time to joint arthroplasty in the subset of patients with severe HA was not affected by the severity of factor VIII (FVIII) gene mutations. A systematic review of literature articles reporting joint arthroplasties in HA and HB showed that the proportion of HA patients who had undergone arthroplasties was higher than that of HB patients, in agreement with the findings in our Italian cohort. These data suggest that the 2 inherited coagulation disorders have a different severity of clinical phenotype.
Probing the mitotic history and developmental stage of hematopoietic cells using single telomere length analysis (STELA)
Authors: Hills Mark , Lücke Kai , Chavez Elizabeth A. , Eaves Connie J. , Lansdorp Peter M. 
Published: April 2009

AbstractIn most human somatic cells, telomeres shorten as a function of DNA replication. Telomere length is therefore an indirect measure of the replicative history of cells. We measured the telomere lengths at XpYp chromosomes in purified human hematopoietic populations enriched for stem cells (Lin−CD34+CD38−Rho−) and successively more mature cells. The average telomere length showed expected length changes, pointing to the utility of this method for classifying novel differentiation markers. Interestingly, the frequency of abruptly shortened telomeres increased in terminally differentiated adult populations, suggesting that damage to telomeric DNA occurs or is not repaired upon hematopoietic differentiation. When Lin−CD34+CD38−Rho− cord blood cells were transplanted into immunodeficient mice, the telomeres of the most primitive regenerated human hematopoietic cells lost approximately 3 kb, indicative of more than 30 cell divisions. Further losses in differentiating cells were similar to those observed in pretransplantation cell populations. These results indicate extensive self-renewal divisions of human hematopoietic stem cells are the primary cause of telomere erosion upon transplantation rather than added cell divisions in downstream progenitors.
Alterations in oestrogen metabolism: implications for higher penetrance of familial pulmonary arterial hypertension in females
Authors: Austin E. D. , Cogan J. D. , West J. D. , Hedges L. K. , Hamid R. , Dawson E. P. , Wheeler L. A. , Parl F. F. , Loyd J. E. , Phillips J. A. 
Published: April 2009

Mutations in bone morphogenetic protein receptor type 2 (BMPR2) cause familial pulmonary arterial hypertension (FPAH), but the penetrance is reduced and females are significantly overrepresented. In addition, gene expression data implicating the oestrogen-metabolising enzyme CYP1B1 suggests a detrimental role of oestrogens or oestrogen metabolites. We examined genetic and metabolic markers of altered oestrogen metabolism in subjects with aBMPR2mutation.Genotypes forCYP1B1 Asn453Ser(N453S) were determined for 140BMPR2mutation carriers (86 females and 54 males). Nested from those subjects, a case–control study of urinary oestrogen metabolite levels (2-hydroxyoestrogen (2-OHE) and 16α-hydroxyoestrone (16α-OHE1)) was conducted in females (five affected mutation carriersversussix unaffected mutation carriers).Among females, there was four-fold higher penetrance among subjects homozygous for the wild-type genotype (N/N) than those with N/S or S/S genotypes (p = 0.005). Consistent with this finding, the 2-OHE/16α-OHE1ratio was 2.3-fold lower in affected mutation carriers compared to unaffected mutation carriers (p = 0.006).Our findings suggest that variations in oestrogens and oestrogen metabolism modify FPAH risk. Further investigation of the role of oestrogens in this disease with profound sex bias may yield new insights and, perhaps, therapeutic interventions.
Elastin expression in very severe human COPD
Authors: Deslee G. , Woods J. C. , Moore C. M. , Liu L. , Conradi S. H. , Milne M. , Gierada D. S. , Pierce J. , Patterson A. , Lewit R. A. , Battaile J. T. , Holtzman M. J. , Hogg J. C. , Pierce R. A. 
Published: April 2009

Alveolar elastic fibres are key targets of proteases during the pathogenesis of chronic obstructive pulmonary disease (COPD). In the current study, we hypothesised that a response to injury leads to enhanced alveolar elastin gene expression in very severe COPD.Lung samples obtained from 43 patients, including 11 with very severe COPD (stage 4), 10 donors, 10 with moderate/severe COPD (stage 2–3) and 12 non-COPD subjects, were analysed for elastin mRNA expression by real-time RT-PCR andin situhybridisation. Alveolar elastic fibres were visualised using Hart's staining of sections of frozen inflated lungs obtained from 11 COPD stage 4 patients and three donor lungs.Compared with donors, non-COPD and stage 2–3 COPD, elastin mRNA expression was significantly increased in very severe COPD lungs (12-fold change), and localisedin situhybridisation induced elastin expression to alveolar walls. Compared with donors, alveolar elastic fibres also comprised a greater volume fraction of total lung tissue in very severe COPD lungs (p<0.01), but elastic fibre content was not increased per lung volume, and desmosine content was not increased.The present study demonstrates enhanced alveolar elastin expression in very severe COPD. The efficiency of this potential repair mechanism and its regulation remain to be demonstrated.
Predictors of residual sleepiness in adequately treated obstructive sleep apnoea patients
Authors: Koutsourelakis I. , Perraki E. , Economou N. T. , Dimitrokalli P. , Vagiakis E. , Roussos C. , Zakynthinos S. 
Published: April 2009

Some patients with obstructive sleep apnoea syndrome (OSAS; respiratory distress index (RDI) of >5 events·h−1) experience residual excessive daytime subjective sleepiness (Epworth Sleepiness Scale (ESS) score of >10), despite adequate use of continuous positive airway pressure (CPAP) therapy. The aim of the present study was to identify clinical and polysomnographic predictors of this sleepiness.Clinical and polysomnographic variables and ESS score were evaluated in 208 OSAS patients with an ESS score of >10 before (initial assessment) and after ≥6 months of adequate (≥4 h·day−1) CPAP use.Following CPAP treatment, 114 (55%) patients showed an abnormal ESS score (>10; CPAP nonresponders), whereas 94 (45%) showed a normal ESS score (<11; CPAP responders). Of the CPAP responders, none had a history of depression, whereas the converse was true for 38.8% of CPAP nonresponders. In addition, multivariate logistic regression analysis revealed that the independent predictors of residual excessive daytime sleepiness following CPAP therapy were a history of diabetes and heart disease, and a higher ESS score and lower RDI on initial assessment.In conclusion, predictors of residual excessive sleepiness in adequately CPAP-treated OSAS were a history of depression, diabetes and heart disease, and a higher ESS score and lower RDI on initial assessment.