4,068 research outputs found
Delineating the polarized and unpolarized photon distributions of the nucleon in eN collisions
The production rates of lepton-photon and dimuon pairs at the HERA collider
and the HERMES experiment are evaluated in the leading order equivalent photon
approximation. It is shown that the production rates are sufficient to
facilitate the extraction of the polarized and unpolarized equivalent photon
distributions of the proton and neutron in the available kinematical regions.
It is pointed out that these results indicate the possibility of additional,
independent, tests concerning the unpolarized and polarized structure functions
F_{1,2}^N and g_{1,2}^N, respectively, of the nucleon.Comment: Final version, to appear in Eur. Phys.
The Higgs Sector of the Minimal 3 3 1 Model Revisited
The mass spectrum and the eigenstates of the Higgs sector of the minimal 3 3
1 model are revisited in detail. There are discrepancies between our results
and previous results by another author.Comment: 20 pages, latex, two figures. One note and one reference are adde
evaluation of upper limb sense of position in healthy individuals and patients after stroke
The aims of this study were to develop and evaluate reliability of a quantitative assessment tool for upper limb sense of position on the horizontal plane. We evaluated 15 healthy individuals (controls) and 9 stroke patients. A robotic device passively moved one arm of the blindfolded participant who had to actively move his/her opposite hand to the mirror location in the workspace. Upper-limb's position was evaluated by a digital camera. The position of the passive hand was compared with the active hand's 'mirror' position. Performance metrics were then computed to measure the mean absolute errors, error variability, spatial contraction/expansion, and systematic shifts. No significant differences were observed between dominant and non-dominant active arms of controls. All performance parameters of the post-stroke group differed significantly from those of controls. This tool can provide a quantitative measure of upper limb sense of position, therefore allowing detection of changes due to rehabilitation
Intensification of the freeze drying process by the control of both freezing and primary drying steps
The problem of optimization of freeze-drying cycles is addressed, with emphasis in both freezing and primary drying steps. In particular, this study shows that the control of the nucleation event produces more uniform batches (as ice nucleation is induced in all the vials of batch almost at the same time and temperature) and allows a marked reduction in the duration of the optimized cycle (if compared to cycles carried out with conventional stochastic nucleation)
Karst geomorphology of the “Canale di Pirro” polje, Apulia (Southern Italy).
In karst environment, a geomorphological map is a powerful instrument, which play a crucial role in understanding earth surface processes and landscape evolution. Furthermore, it could be very useful for speleological perspectives, natural resources exploitation and geo-hazards management (flood, sinkhole, subsidence, etc.), providing useful information that enhance the knowledge of the territory. In this work, we present a geomorphological map of the polje of “Canale di Pirro”, sited in the central part of Apulia Region, in Southern Italy, among the most interesting karst lands in the Mediterranean area. The map covers150km2withanelevationrangeof100-450ma.s.l.Thisareaisoneofthemostremarkablekarstlandforms in the region, characterized underground by a very interesting system of caves, that reaches the water table at a depth of -264 meters. The karst system, known as “Inghiottitoio di Masseria Rotolo”, following scuba-diving exploration below the watertable, has become with a depth of 324m, the deepest known cave in Apulia. The polje is bounded on both sides by tectonically-controlled ridges, showing an overall length of some 12 km. In ancient maps, dating back to the 16th century, the area is represented as crossed by a long river, called Cana. The map obtained derives from the integration of interpretation of aerial photographs, analysis of a digital elevation model and field surveys in order to obtain a correct distribution of landforms and fluvial processes, such as different varieties of karst depressions, conical hills, erosional gullies, alluvial fans and tectonic structures. It provides relevant information about the surface drainage processes, and for understanding, among other things, the groundwater circulation and the related recharge processes. This geomorphological map is part of a wider project, that combined geological, hydrogeological research and chemical analyses of the groundwater. It provides support to the ongoing studies of this part of Apulia region aimedto betterunderstand thegeological processes that originatedthe polje and its later evolution, and the related underground cave system. Further, it might also suggest possible improvements in land management and in the future choice of useful tools for the control of the quality and quantity of karst groundwater
Identification of a novel Sp1 splice variant as a strong transcriptional activator.
The transcription factor Sp1 regulates expression of numerous genes involved in many cellular processes.
Different post-transcriptional modifications can influence the transcriptional control activity and stability
of Sp1. In addition to these modifications, alternative splicing isoforms may also be the basis of its distinct
functional activities. In this study, we identified a novel alternative splice isoform of Sp1 named
Sp1c. This variant is generated by exclusion of a short domain, which we designate a, through alternative
splice acceptor site usage in the exon 3. The existence of this new isoform was confirmed in vivo by Western
blotting analysis. Although at very low levels, Sp1c is ubiquitously expressed, as seen in its fulllength
Sp1. A preliminary characterization of Sp1c shows that: (a) Sp1c works as stronger activator of
transcription than full-length Sp1; (b) percentage of HEK293 Sp1c-overexpressing cells is higher in G1
phase and lower in S phase than percentage of HEK293 Sp1-overexpressing cells
A GBT Survey of the HALOGAS Galaxies and Their Environments I: Revealing the full extent of HI around NGC891, NGC925, NGC4414 & NGC4565
We present initial results from a deep neutral hydrogen (HI) survey of the
HALOGAS galaxy sample, which includes the spiral galaxies NGC891, NGC925,
NGC4414, and NGC4565, performed with the Robert C. Byrd Green Bank Telescope
(GBT). The resulting observations cover at least four deg around these
galaxies with an average 5 detection limit of 1.210
cm over a velocity range of 20 km s and angular scale of 9.1.
In addition to detecting the same total flux as the GBT data, the spatial
distribution of the GBT and original Westerbork Synthesis Radio Telescope
(WSRT) data match well at equal spatial resolutions. The HI mass fraction below
HI column densities of 10 cm is, on average, 2\%. We discuss the
possible origins of low column density HI of nearby spiral galaxies. The
absence of a considerable amount of newly detected HI by the GBT indicates
these galaxies do not have significant extended diffuse HI structures, and
suggests future surveys planned with the SKA and its precursors must go
\textit{at least} as deep as 10 cm in column density to
significantly increase the probability of detecting HI associated with the
cosmic web and/or cold mode accretion.Comment: Accepted for publication in The Astrophysical Journal; 28 pages, 15
figure
- …