oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 12 )

2019 ( 697 )

2018 ( 818 )

2017 ( 752 )

Custom range...

Search Results: 1 - 10 of 462081 matches for " A. Stahl "
All listed articles are free for downloading (OA Articles)
Page 1 /462081
Display every page Item
Facing the music: Three issues in current research on singing and aphasia
Benjamin Stahl,Sonja A. Kotz
Frontiers in Psychology , 2014, DOI: 10.3389/fpsyg.2014.01033
Abstract: Left-hemisphere stroke patients suffering from speech and language disorders are often able to sing entire pieces of text fluently. This finding has inspired a number of music-based rehabilitation programs, most notable among them a treatment known as Melodic Intonation Therapy (Albert et al., 1973). According to the inventors of the treatment, singing should promote a transfer of language function from left frontotemporal neural networks to their preserved right-hemisphere homologues. Although singing indeed engages right frontotemporal areas (Callan et al., 2006; ?zdemir et al., 2006), it does not seem to induce a transfer of language function from the left to the right hemisphere (Belin et al., 1996; Jungblut et al., 2014). Nonetheless, several studies confirmed the promising role of singing (Mills, 1904; Gerstmann, 1964; Keith & Aronson, 1975; Tomaino, 2010) and the overall efficacy of Melodic Intonation Therapy (van der Meulen et al., 2014).
Response of Epilithic Diatom Communities to Downstream Nutrient Increases in Castelhano Stream, Venâncio Aires City, RS, Brazil  [PDF]
Juliara Stahl B?hm, Marilia Schuch, Adriana Düpont, Eduardo A. Lobo
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.411A003
Abstract:

The Castelhano Stream Hydrographic Basin, located in the city of Venancio Aires, RS, Brazil, shows an area of 675.3 km2, highlighting the Castelhano Stream as their main water course. The stream is the main responsiblity for the local water supply; however, there are no published studies in the literature regarding their water quality. In this context, the present research aimed to assess the water quality of Castelhano Stream in terms of organic pollution and eutrophication, applying the Biological Water Quality Index (BWQI), which uses epilithic diatoms communities as bioindicators. Biological samples were collected at three sampling stations along the stream in the months of September, November and December 2012. The results showed 81 identified species, distributed in 30 genera. The water pollution levels detected ranged from strong (66.7%) and very strong (33.3%), with differences in species composition between sampling stations. The sampling station S1 in the upper reaches was characterized by the presence of indicative species of acidophilus and lentic environments with large amounts of organic matter. The sampling stations S2 and S3, in the intermediate and lower reaches, respectively, showed a substitution of species in the community, with the presence of highly tolerant taxa to organic pollution and eutrophication. The high pollution levels detected along the basin are related to the nutrients and high organic load originating from livestock, domestic and industrial waste, as well as excess fertilizers and agricultural inputs used in farming. The results demonstrate the necessity to implement mitigation measures to contain the processes of organic pollution and eutrophication detected due to the dangers offered to public health and the environment.

Rotated Salter-Harris type II fracture of the phalanx
S. Stahl,A. Lerner,E. Calif
Journal of Orthopaedics and Traumatology , 2004, DOI: 10.1007/s10195-004-0070-5
Abstract: A Salter-Harris type II fracture with a rotational deformity involving the proximal phalanx of the ring finger is described for the first time. An undetected rotational deformity accompanying a Salter- Harris fracture compounds the fracture’s healing since it does not remodel, resulting in a malrotated union. Therefore, a cautious clinical and radiographic assessment is required, and fracture reduction should always be coupled with a correction of any evident rotational deformity.
Masses of the astrometric SB2 ζOri A
Th. Rivinius,C. A. Hummel,O. Stahl
Physics , 2010, DOI: 10.1017/S1743921311011367
Abstract: We report the first dynamic mass for an O-type supergiant, the interferometrically resolved SB2 system \zeta Ori A (O9.5Ib+B0/1). The separation of the system excludes any previous mass-transfer, ensuring that the derived masses can be compared to single star evolutionary tracks.
Sensitivity of a data-driven soil water balance model to estimate summer evapotranspiration along a forest chronosequence
J. A. Bre a Naranjo, M. Weiler,K. Stahl
Hydrology and Earth System Sciences (HESS) & Discussions (HESSD) , 2011,
Abstract: The hydrology of ecosystem succession gives rise to new challenges for the analysis and modelling of water balance components. Recent large-scale alterations of forest cover across the globe suggest that a significant portion of new biophysical environments will influence the long-term dynamics and limits of water fluxes compared to pre-succession conditions. This study assesses the estimation of summer evapotranspiration along three FLUXNET sites at Campbell River, British Columbia, Canada using a data-driven soil water balance model validated by Eddy Covariance measurements. It explores the sensitivity of the model to different forest succession states, a wide range of computational time steps, rooting depths, and canopy interception capacity values. Uncertainty in the measured EC fluxes resulting in an energy imbalance was consistent with previous studies and does not affect the validation of the model. The agreement between observations and model estimates proves that the usefulness of the method to predict summer AET over mid- and long-term periods is independent of stand age. However, an optimal combination of the parameters rooting depth, time step and interception capacity threshold is needed to avoid an underestimation of AET as seen in past studies. The study suggests that summer AET could be estimated and monitored in many more places than those equipped with Eddy Covariance or sap-flow measurements to advance the understanding of water balance changes in different successional ecosystems.
The potential of observed soil moisture dynamics for predicting summer evapotranspiration in a successional chronosequence
J. A. Bre?a Naranjo,M. Weiler,K. Stahl
Hydrology and Earth System Sciences Discussions , 2011, DOI: 10.5194/hessd-8-5301-2011
Abstract: The hydrology of ecosystem succession gives rise to new challenges for the analysis and modeling of water balance components. Recent large-scale alterations of forest cover across the globe suggest that a significant portion of new biophysical environments will influence the long-term dynamics and limits of water fluxes compared to pre-succession conditions. This study explores the potential of modeling actual evapotranspiration (AET) in the summer along a successional forest by observed soil moisture dynamics. We applied two parsimonious data-driven soil water balance models to the Canadian FLUXNET sites at Campbell River, British Columbia. Simulated AET was compared to water vapor measurements from 2001 to 2008 and the models' sensitivity to inter-annual climatic variability and computation time step was tested. With the exception of the mature forest during an extremely dry summer, the results confirm the potential of using observed soil moisture dynamics as a method to estimate summer AET within an acceptable error range albeit substantial differences along the successional forested ecosystem. The study suggests that summer AET could be estimated and monitored in many more places than those equipped with eddy-covariance or sap-flow measurements to advance the understanding of the water balance of different successional ecosystems.
Stable carbon isotopes on methane in ocean and lake water
E. Faber,U. Berner,A. Hollerbach,P. Gerling,W. Stahl
Chinese Science Bulletin , 1998, DOI: 10.1007/BF02891419
Abstract:
Low-frequency variability of European runoff
L. Gudmundsson, L. M. Tallaksen, K. Stahl,A. K. Fleig
Hydrology and Earth System Sciences (HESS) & Discussions (HESSD) , 2011,
Abstract: This study investigates the low-frequency components of observed monthly river flow from a large number of small catchments in Europe. The low-frequency components, defined as fluctuations on time scales longer than one year, were analysed both with respect to their dominant space-time patterns as well as their contribution to the variance of monthly runoff. The analysis of observed streamflow and corresponding time series of precipitation and temperature, showed that the fraction of low-frequency variance of runoff is on average larger than, and not correlated to, the fraction of low-frequency variance of precipitation and temperature. However, it is correlated with mean climatic conditions and is on average lowest in catchments with significant influence of snow. Furthermore, it increases (decreases) under drier (wetter) conditions – indicating that the average degree of catchment wetness may be a primary control of low-frequency runoff dynamics. The fraction of low-frequency variance of runoff is consistently lower in responsive catchments, with a high variability of daily runoff. The dominant space-time patterns of low-frequency runoff in Europe, identified using nonlinear dimension reduction, revealed that low-frequency runoff can be described with three modes, explaining together 80.6% of the variance. The dominant mode has opposing centres of simultaneous variations in northern and southern Europe. The secondary mode features a west-east pattern and the third mode has its centre of influence in central Europe. All modes are closely related to the space-time patterns extracted from time series of precipitation and temperature. In summary, it is shown that the dynamics of low-frequency runoff follows well known continental-scale atmospheric features, whereas the proportion of variance attributed to low-frequency fluctuations is controlled by catchment processes and varies with mean climatic conditions. The results may have implications for interpreting the impact of changes in temperature and precipitation on river-flow dynamics.
Low-frequency variability of European runoff
L. Gudmundsson,L. M. Tallaksen,K. Stahl,A. K. Fleig
Hydrology and Earth System Sciences Discussions , 2011, DOI: 10.5194/hessd-8-1705-2011
Abstract: This study investigates the low-frequency components of observed monthly runoff in Europe, to better understand the runoff response to long-term variations in the climate system. The relative variance and the dominant space-time patterns of the low-frequency components of runoff were considered, in order to quantify their relative importance and to get insights in to the controlling factors. The analysis of a recently updated European data set of observed streamflow and corresponding time series of precipitation and temperature, showed that the fraction of low-frequency variance of runoff is on average larger than, and not correlated to, the fraction of low-frequency variance of precipitation and temperature. However, it is correlated with catchment properties as well as mean climatic conditions. The fraction of low-frequency variance of runoff decreases for catchments that respond more directly to precipitation. Furthermore, it increases (decreases) under drier (wetter) conditions – indicating that the average degree of catchment saturation may be a primary control of low-frequency runoff dynamics. The dominant space-time patterns of low-frequency runoff, identified using nonlinear dimension reduction, revealed that low-frequency runoff can be described with three modes, explaining together 80.6% of the variance. The dominant mode has opposing centers of simultaneous variations in northern and southern Europe. The secondary mode features a west-east pattern and the third mode has its centre of influence in central Europe. All modes are closely related to the space-time patterns extracted from time series of precipitation and temperature. In summary, it is shown that the dynamics of low-frequency runoff follows large-scale atmospheric features, whereas the proportion of variance attributed to low-frequency fluctuations is controlled by catchment processes and varies with the mean climatic conditions. The results may have implications for interpreting the impact of changes in temperature and precipitation on river-flow dynamics.
Escape, capture, and levitation of matter in Eddington outbursts
A. Stahl,W. Klu?niak,M. Wielgus,M. Abramowicz
Physics , 2013, DOI: 10.1051/0004-6361/201321595
Abstract: Context: An impulsive increase in luminosity by one half or more of the Eddington value will lead to ejection of all optically thin plasma from Keplerian orbits around the radiating star, if gravity is Newtonian and the Poynting-Robertson drag is neglected. Radiation drag may bring some particles down to the stellar surface. On the other hand, general relativistic calculations show that gravity may be balanced by a sufficiently intense radiation field at a certain distance from the star. Aims: We investigate the motion of test particles around highly luminous stars to determine conditions under which plasma may be ejected from the system. Results: In Einstein's gravity, if the outburst is close to the Eddington luminosity, all test particles orbiting outside an "escape sphere" will be ejected from the system, while all others will be captured from their orbits onto the surface of another sphere, which is well above the stellar surface, and may even be outside the escape sphere, depending on the value of luminosity. Radiation drag will bring all the captured particles to rest on this "Eddington capture sphere," where they will remain suspended in an equilibrium state as long as the local flux of radiation does not change and remains at the effective Eddington value.
Page 1 /462081
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.