bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessing the Impacts of Global Warming on Snowpack in the Washington Cascades*
Authors: Casola Joseph H. , Cuo Lan , Livneh Ben , Lettenmaier Dennis P. , Stoelinga Mark T. , Mote Philip W. , Wallace John M. 
Published: December 2008

Abstract
The decrease in mountain snowpack associated with global warming is difficult to estimate in the presence of the large year-to-year natural variability in observations of snow-water equivalent (SWE). A more robust approach for inferring the impacts of global warming is to estimate the temperature sensitivity (λ) of spring snowpack and multiply it by putative past and future temperature rises observed across the Northern Hemisphere.
Estimates of λ can be obtained from (i) simple geometric considerations based on the notion that as the seasonal-mean temperature rises by the amount δT, the freezing level and the entire snowpack should rise by the increment δT/Γ, where Γ is the mean lapse rate; (ii) the regression of 1 April SWE measurements upon mean winter temperatures; (iii) a hydrological model forced by daily temperature and precipitation observations; and (iv) the use of inferred accumulated snowfall derived from daily temperature and precipitation data as a proxy for SWE. All four methods yield an estimated sensitivity of 20% of spring snowpack lost per degree Celsius temperature rise. The increase of precipitation accompanying a 1°C warming can be expected to decrease the sensitivity to 16%.
Considering observations of temperature rise over the Northern Hemisphere, it is estimated that spring snow-water equivalent in the Cascades portion of the Puget Sound drainage basin should have declined by 8%–16% over the past 30 yr resulting from global warming, and it can be expected to decline by another 11%–21% by 2050. These losses would be statistically undetectable from a trend analysis of the region’s snowpack over the past 30 yr.
Scattering of Internal Waves with Frequency Change over Rough Topography
Authors: Nakamura Tomohiro , Awaji Toshiyuki 
Published: December 2008

Abstract
The frequency change in internal gravity waves upon scattering from a rough topography is investigated analytically. For this, sets of appropriate and tractable governing equations for various parameter regimes are derived using the method of multiple scales under the assumption that the amplitude of the bottom topography is small. A solution is shown for a simple case in which an incident internal wave is approximately linear and monochromatic. The solution has the following features: the intrinsic frequencies of the scattered waves are given as the sum and difference of the incident-wave frequency and the Doppler shift (or lee-wave frequency). This Doppler shift causes the change in the frequency. Hence, the assumption of frequency conservation is not valid if the Doppler shift is significant, that is, when the horizontal scale of the bottom roughness (or the length scale in the plane of the slope) is on the order of or much less than that of the incident-wave flow excursion. This condition can be satisfied in a realistic parameter range.
The occurrence of such a frequency change has the following implications: first, it affects the estimate of the boundary mixing induced by the scattering because the energy redistribution in the vertical wavenumber space on scattering differs from that estimated using the assumption of frequency conservation. This effect happens because for a given horizontal wavenumber, the change in the frequency alters the vertical wavenumber of the scattered waves through the dispersion relation. Furthermore, if the incident waves are not monochromatic, even the leading-order scattered waves cannot be obtained by the superposition of the solutions for all the Fourier components of the incident waves because of the difference in the Doppler shift. Second, the effects of the background flow associated with the incident and primary reflected waves are significant when the frequency change occurs such that the background flow can create a critical level and/or advect scattered waves. The former causes mixing and background-flow acceleration, and the latter is favorable for the amplification of the scattered waves through superposition. Third, the resulting energy redistribution in frequency space could modify the spectrum shape of the oceanic internal waves, which is considered to affect both interior and boundary mixing.
Interannual and Decadal Variations in Cross-Shelf Transport in the Gulf of Alaska
Authors: Combes Vincent , Di Lorenzo Emanuele , Curchitser Enrique 
Published: December 2008

Abstract
The marine ecosystem of the Gulf of Alaska (GOA) is one of the richest on the planet. The center of the GOA is characterized by high-nutrient and low-chlorophyll-a concentration. Recent observational studies suggest that advection of iron-rich coastal water is the primary mechanism controlling open ocean productivity. Specifically, there is evidence that mesoscale eddies along the coastal GOA entrain iron-rich coastal waters into the ocean interior. This study investigates the cross-shelf transport statistics in the GOA using a free-surface, hydrostatic, eddy-resolving primitive equation model over the period 1965–2004. The statistics of coastal water transport are computed using a model passive tracer, which is continuously released at the coast. The passive tracer can thus be considered a proxy for coastal biogeochemical quantities such as silicate, nitrate, iron, or oxygen, which are critical for explaining the GOA ecosystem dynamics. On average along the Alaska Current, it has been shown that at the surface while the advection of tracers by the average flow is directed toward the coast consistent with the dominant downwelling regime of the GOA, it is the mean eddy fluxes that contribute to offshore advection into the gyre interior. South of the Alaskan Peninsula, both the advection of tracers by the average flow and the mean eddy fluxes contribute to the mean offshore advection. On interannual and longer time scales, the offshore transport of the passive tracer in the Alaskan Stream does not correlate with large-scale atmospheric forcing, nor with local winds. In contrast in the Alaska Current region, stronger offshore transport of the passive tracer coincides with periods of stronger downwelling (in particular during positive phases of the Pacific decadal oscillation), which trigger the development of stronger eddies.
Water Vapor Profiling Using a Widely Tunable, Amplified Diode-Laser-Based Differential Absorption Lidar (DIAL)
Authors: Nehrir Amin R. , Repasky Kevin S. , Carlsten John L. , Obland Michael D. , Shaw Joseph A. 
Published: December 2008

Abstract
A differential absorption lidar (DIAL) instrument for automated profiling of water vapor in the lower troposphere has been designed, tested, and is in routine operation at Montana State University. The laser transmitter for the DIAL instrument uses a widely tunable external cavity diode laser (ECDL) to injection seed two cascaded semiconductor optical amplifiers (SOAs) to produce a laser transmitter that accesses the 824–841-nm spectral range. The DIAL receiver utilizes a 28-cm-diameter Schmidt–Cassegrain telescope; an avalanche photodiode (APD) detector; and a narrowband optical filter to collect, discriminate, and measure the scattered light. A technique of correcting for the wavelength-dependent incident angle upon the narrowband optical filter as a function of range has been developed to allow accurate water vapor profiles to be measured down to 225 m above the surface. Data comparisons using the DIAL instrument and collocated radiosonde measurements are presented demonstrating the capabilities of the DIAL instrument.
A Multicase Comparative Assessment of the Ensemble Kalman Filter for Assimilation of Radar Observations. Part I: Storm-Scale Analyses
Authors: Aksoy Altuğ , Dowell David C. , Snyder Chris 
Published: December 2008

Abstract
The effectiveness of the ensemble Kalman filter (EnKF) for assimilating radar observations at convective scales is investigated for cases whose behaviors span supercellular, linear, and multicellular organization. The parallel EnKF algorithm of the Data Assimilation Research Testbed (DART) is used for data assimilation, while the Weather Research and Forecasting (WRF) Model is employed as a simplified cloud model at 2-km horizontal grid spacing. In each case, reflectivity and radial velocity measurements are utilized from a single Weather Surveillance Radar-1988 Doppler (WSR-88D) within the U.S. operational network. Observations are assimilated every 2 min for a duration of 60 min and correction of folded radial velocities occurs within the EnKF. Initial ensemble uncertainty includes random perturbations to the horizontal wind components of the initial environmental sounding. The EnKF performs effectively and with robust results across all the cases. Over the first 18–30 min of assimilation, the rms and domain-averaged prior fits to observations in each case improve significantly from their initial levels, reaching comparable values of 3–6 m s−1 and 7–10 dBZ. Representation of mesoscale uncertainty, albeit in the simplest form of initial sounding perturbations, is a critical part of the assimilation system, as it increases ensemble spread and improves filter performance. In addition, assimilation of “no precipitation” observations (i.e., reflectivity observations with values small enough to indicate the absence of precipitation) serves to suppress spurious convection in ensemble members. At the same time, it is clear that the assimilation is far from optimal, as the ensemble spread is consistently smaller than what would be expected from the innovation statistics and the assumed observation-error variance.
Medium Lead-Time Predictability of Intraseasonal Variability of Rainfall in West Africa
Authors: Sultan Benjamin , Janicot Serge , Correia Cyrille 
Published: December 2008

Abstract
The variability of the West African monsoon on the intraseasonal time scale is a major issue for agricultural strategy, as the occurrence of dry spells can strongly impact yields of rain-fed crops. This study investigates this intraseasonal variability of rainfall over West Africa and gives a first overview of its predictability at a medium lead time.
A statistical method, the singular spectrum analysis, is applied to a ground-based rainfall index in West Africa to describe first temporal patterns of the main leading modes of intraseasonal variability. The results point out the existence of one oscillatory mode of 34 days, one of 20 days, and one of 14 days. The same methodology is applied to rainfall from two reanalysis datasets and to deep convection from satellite data in order to assess the accuracy of the representation of intraseasonal variability in these datasets. It is shown that although the day-to-day variability of rainfall is not well captured in these datasets, intraseasonal features and, in particular, the low-frequency mode are very well reproduced.
The medium lead-time predictability (5–10 days) of the intraseasonal modes is investigated using both the dynamical forecast scheme of the ECMWF and a statistical method, the maximum entropy method. For the latter method, an operational application using unfiltered input data is also considered. The performance of these prediction schemes is compared using a simple reference technique in which forecasts are based entirely on persistence. It is found that statistical predictions are much more promising than the dynamical ones, though they encounter problems when applied operationally. In an operational application, the forecast skill for the 10–90-day intraseasonal band is low but the predictability of individual intraseasonal modes is higher. The stability of the forecast skill levels is influenced by the characteristics of the intraseasonal mode. When the characteristics (i.e., amplitude and period) of the considered intraseasonal mode are well defined, skillful forecasts can be obtained. However, when the characteristics change rapidly, the forecast fails.
Association between Carotid and Coronary Artery Disease in Patients with Aortic Valve Stenosis: An Angiographic Study
Authors: Antonini-Canterin Francesco , Leiballi Elisa , Capanna Michele , Burelli Claudio , Cassin Matteo , Macor Franco , Grandis Umberto , Nicolosi Gian Luigi 
Published: December 2008

Background Patients with aortic stenosis have a high prevalence of coronary artery disease, but there is little information about the association of coronary artery disease and carotid artery disease. Methods The study includes 317 consecutive patients with aortic stenosis, who underwent carotid and coronary angiography during the same catheterization before aortic valve replacement. Results At univariate analysis, the prevalence of coronary artery disease was associated with (1) presence of carotid artery disease ( P < .001); (2) angina pectoris as presentation symptom ( P < .001); (3) age more than 65 years ( P < .05); and (4) hypertension ( P < .05). At multivariate analysis, only carotid artery disease, angina, and age emerged as independent predictors of coronary artery disease. The combination of 2 variables (carotid artery disease, angina) allowed the identification of 4 groups, with decreasing prevalence of coronary artery disease: (1) angina+/carotid artery disease+: 85%; (2) angina—/ carotid artery disease+: 50%; (3) angina+/carotid artery disease—: 41%; (4) angina—/carotid artery disease—: 21% ( P < .001). Conclusion In patients with symptomatic aortic stenosis, the presence of significant carotid artery disease is a strong marker of significant coronary artery disease.
Development of a reliable self-report outcome measure for pragmatic trials of communication therapy following stroke: the Communication Outcome after Stroke (COAST) scale
Authors: Long AF , Hesketh A. , Paszek G. , Booth M. , Bowen A. 
Published: December 2008

Objective: To develop and validate a clinically feasible measure of communication effectiveness for people with any type of communication problem following stroke. Design: Cross-sectional, interview-based, psychometric study, building on the development phase for construction of the Communication Outcome after Stroke (COAST) scale. Setting: A community sample from the northwest of England, UK. Subjects: One hundred and two people with communication problems (aphasia and/or dysarthria) following a stroke, within the previous 4—12 months. Interventions: Administration of the COAST scale, on two occasions, within a two-week period, and collection of demographic and other data relating to disability, degree of aphasia (where appropriate) and hospital diagnosis of aphasia/dysarthria. Main measures: Acceptability (missing values), reliability (internal consistency and test—retest reliability) and item analysis (item redundancy). Results: Ninety-seven (visit 1) and 98 (visit 2) respondents provided usable data for the psychometric analysis. The 29-item COAST scale showed good acceptability (few missing values, sample spread 28—100%), internal consistency and test—retest reliability for the scale (α = 0.95; ICC = 0.90) and its subscales (α = 0.65—0.93; ICC = 0.72—0.88), but possible item redundancy. A revised scale of 20 items was produced, demonstrating good internal consistency and test—retest reliability (α = 0.83—92; ICC = 0.72—0.88). Conclusions: The COAST is a patient-centred, practical and reliable measure that can be used to assess self-perceived communication effectiveness for people with aphasia and/or dysarthria. Further testing on construct validity and responsiveness to change is needed before the measure can be firmly recommended for use within clinical practice and research.
Comparison of orthostatic reactions of patients still unconscious within the first three months of brain injury on a tilt table with and without integrated stepping. A prospective, randomized crossover pilot trial
Authors: Luther Marianne S , Krewer Carmen , Müller Friedemann , Koenig Eberhard 
Published: December 2008

Objective: To determine whether passive leg movement during tilt table mobilization reduces the incidence of orthostatic dysfunction in mobilization of patients being comatose or semi-comatose early after brain injury. Design: Randomized crossover pilot trial using sequential testing. Setting: Neurorehabilitation hospital. Subjects: Nine patients still unconscious within the first three months of brain injury (5 men, 4 women; age 51 ± 20 years). Intervention: Patients were subjected once to a conventional tilt table and once to a tilt table with an integrated stepping device. Main outcome measure: The number of syncopes/presyncopes (orthostatic hypotension, tachypnoea, increased sweating) during interventions. Results: One patient had presyncopes on both devices, six patients had presyncopes on the conventional tilt table but not on the tilt table with integrated stepping, and two patients did not exhibit presyncopal symptoms on either device. There were significantly more incidents on the tilt table without than on the one with an integrated stepping device (P<0.05) at tilts of 50 or 70 degrees respectively. Conclusion: Patients tolerate greater degrees of head-up tilt better with simultaneous leg movement.
Screening for cognitive deficits after stroke: a comparison of three screening tools
Authors: Nøkleby Kjersti , Boland Erik , Bergersen Hilde , Schanke Anne-Kristine , Farner Lasse , Wagle Jørgen , Wyller Torgeir Bruun 
Published: December 2008

Objective: To assess the concurrent validity of three screening tests for focal cognitive impairments after stroke. Design: Comparison of results from the screening tests with those from a more comprehensive neuropsychological battery. Setting: Stroke rehabilitation wards of a general hospital and a rehabilitation hospital. Subjects: Forty-nine stroke patients (25—91 years, 35% women). Measures: Screening tests were the Cognistat, the Screening Instrument for Neuropsychological Impairments in Stroke (SINS) and the Clock Drawing Test. Health professionals, blind to the results of the reference method, did the screening. Reference method was a neuropsychological assessment based on the Norwegian Basic Neuropsychological Assessment, classifying the patients as `impaired' or `not impaired' within the following cognitive domains: language, visuospatial function, attention and neglect, apraxia, speed in unaffected arm, and memory. Results: The best sensitivity (95% confidence interval) was achieved for language problems by Cognistat, naming (80%, 44—98); for visuospatial dysfunction, attention deficits and reduced speed, all by SINS visuocognitive (82%, 60—95, 72%, 39—94, and 78%, 56—93, respectively); and for memory problems by Cognistat memory (69%, 52—87). The data were insufficient to assess any subtest for apraxia. Sensitivity in detecting deficits in any domain was 82% (71—94) for the Cognistat composite score, 71% (57—85) for the SINS composite score, and 63% (49—78) for the most sensitive score of the Clock Drawing Test. Conclusion: The Cognistat and the SINS may be used as screening instruments for cognitive deficits after stroke, but cannot replace a neuropsychological assessment. The Clock Drawing Test added little to the detection of cognitive deficits.
Does monitoring change in function in community-dwelling older adults alter outcome? A randomized controlled trial
Authors: Richardson Julie , Chan David , Risdon Kathy , Giles Christopher , Mulveney Susan , Cripps Donna 
Published: December 2008

Objective: To determine whether information about an older person's physical functioning provided to the patient and his or her physician delays functional decline and improves health outcomes. Design: A randomized controlled trial was undertaken; the assessors were not blinded to the group allocation. Setting: The study took place in a clinic within a hospital setting. Participants: Two hundred and sixty-five community-dwelling people over 65 years were recruited from family practice units. Interventions: The intervention group received assessments of physical function with feedback to the participant and the participant's family physician or functional assessments alone over 18 months. Self-report measures for health status using the Short Form-36 (SF-36) and preclinical disability were used together with performance measures which included the lower extremity performance test and muscle strength. Results: There were small, statistically significant group/time interactions which included disability scores, F=4.78, P ≤0.05), and the vitality subscale of the SF-36, F=7.47, P ≤0.01). Conclusion: Providing information about the results of detailed assessment of physical functioning to older adults and their physicians did not show significant differences in function scores between the intervention and control groups.
A pilot study of activity-based therapy in the arm motor recovery post stroke: a randomized controlled trial
Authors: Rabadi MH , Galgano M. , Lynch D. , Akerman M , Lesser M. , Volpe BT 
Published: December 2008

Objective: To determine the efficacy of activity-based therapies using arm ergometer or robotic or group occupational therapy for motor recovery of the paretic arm in patients with an acute stroke (≤4 weeks) admitted to an inpatient rehabilitation facility, and to obtain information to plan a large randomized controlled trial. Design: Prospective, randomized controlled study. Setting: Stroke unit in a rehabilitation hospital. Subjects: Thirty patients with an acute stroke (≤4 weeks) who had arm weakness (Medical Research Council grade 2 or less at the shoulder joint). Intervention: Occupational therapy (OT) group (control) (n = 10), arm ergometer (n = 10) or robotic (n = 10) therapy group. All patients received standard, inpatient, post-stroke rehabilitation training for 3 hours a day, plus 12 additional 40-minute sessions of the activity-based therapy. Main measures: The primary outcome measures were discharge scores in the Fugl-Meyer Assessment Scale for upper limb impairment, Motor Status Scale, total Functional Independence Measure (FIM) and FIM-motor and FIM-cognition subscores. Results: The three groups (OT group versus arm ergometer versus robotic) were comparable on clinical demographic measures except the robotic group was significantly older and there were more haemorrhagic stroke patients in the arm ergometer group. After adjusting for age, stroke type and outcome measures at baseline, a similar degree of improvement in the discharge scores was found in all of the primary outcome measures. Conclusion: This study suggests that activity-based therapies using an arm ergometer or robot when used over shortened training periods have the same effect as OT group therapy in decreasing impairment and improving disability in the paretic arm of severely affected stroke patients in the subacute phase.
Dysfunctional homologous recombination mediates genomic instability and progression in myeloma
Authors: Shammas Masood A. , Shmookler Reis Robert J. , Koley Hemanta , Batchu Ramesh B. , Li Cheng , Munshi Nikhil C. 
Published: December 2008

AbstractA prominent feature of most if not all cancers is a striking genetic instability, leading to ongoing accrual of mutational changes, some of which underlie tumor progression, including acquisition of invasiveness, drug resistance, and metastasis. Thus, the molecular basis for the generation of this genetic diversity in cancer cells has important implications in understanding cancer progression. Here we report that homologous recombination (HR) activity is elevated in multiple myeloma (MM) cells and leads to an increased rate of mutation and progressive accumulation of genetic variation over time. We demonstrate that the inhibition of HR activity in MM cells by small inhibitory RNA (siRNAs) targeting recombinase leads to significant reduction in the acquisition of new genetic changes in the genome and, conversely, the induction of HR activity leads to significant elevation in the number of new mutations over time and development of drug resistance in MM cells. These data identify dysregulated HR activity as a key mediator of DNA instability and progression of MM, with potential as a therapeutic target.