322 research outputs found
High luminosity interaction region design for collisions inside high field detector solenoid
An innovatory interaction region has been recently conceived and realized on
the Frascati DA{\Phi}NE lepton collider. The concept of tight focusing and
small crossing angle adopted to achieve high luminosity in multibunch
collisions has evolved towards enhanced beam focusing at the interaction point
with large horizontal crossing angle, thanks to a new compensation mechanism
for the beam-beam resonances. The novel configuration has been tested with a
small detector without solenoidal field yielding a remarkable improvement in
terms of peak as well as integrated luminosity. The high luminosity interaction
region has now been modified to host a large detector with a strong solenoidal
field which significantly perturbs the beam optics introducing new design
challenges in terms of interaction region optics design, beam transverse
coupling control and beam stay clear requirements. Interaction region design
criteria as well as the luminosity results relevant to the structure test are
presented and discussed.Comment: 12 pages, 9 figures, submitted to JINS
High luminosity interaction region design for collisions with detector solenoid
An innovatory interaction region has been recently conceived and realized on
the Frascati DA{\Phi}NE lepton collider. The concept of tight focusing and
small crossing angle adopted until now to achieve high luminosity in multibunch
collisions has evolved towards enhanced beam focusing at the interaction point
with large horizontal crossing angle, thanks to a new compensation mechanism
for the beam-beam resonances. The novel configuration has been tested with a
small detector without solenoidal field yielding a remarkable improvement in
terms of peak as well as integrated luminosity. The high luminosity interaction
region has now been modified to host a large detector with a strong solenoidal
field which significantly perturbs the beam optics introducing new design
challenges in terms of interaction region optics design, beam transverse
coupling control and beam stay clear requirementsComment: 3 pages, 4 figures, presented to the IPAC10 conferenc
Synchrotron oscillation damping due to beam-beam collisions
In DA{\Phi}NE, the Frascati e+/e- collider, the crab waist collision scheme
has been successfully implemented in 2008 and 2009. During the collision
operations for Siddharta experiment, an unusual synchrotron damping effect has
been observed. Indeed, with the longitudinal feedback switched off, the
positron beam becomes unstable with beam currents in the order of 200-300 mA.
The longitudinal instability is damped by bringing the positron beam in
collision with a high current electron beam (~2A). Besides, we have observed a
shift of \approx 600Hz in the residual synchrotron sidebands. Precise
measurements have been performed by using both a commercial spectrum analyzer
and the diagnostics capabilities of the DA{\Phi}NE longitudinal bunch-by-bunch
feedback. This damping effect has been observed in DA{\Phi}NE for the first
time during collisions with the crab waist scheme. Our explanation is that beam
collisions with a large crossing angle produce a longitudinal tune shift and a
longitudinal tune spread, providing Landau damping of synchrotron oscillations.Comment: 3 pages, 5 figures, talk presented to IPAC'10 - Kyoto - May 24-28
201
Imaging of temporomandibular joint: Approach by direct volume rendering
Materials and Methods: We have studied the temporom-andibular joint anatomy, directly on the living, from 3D images obtained by medical imaging Computed Tomography and Nuclear Magnetic Resonance acquisition, and subsequent re-engineering techniques 3D Surface Rendering and Volume Rendering. Data were analysed with the goal of being able to isolate, identify and distinguish the anatomical structures of the joint, and get the largest possible number of information utilizing software for post-processing work.Results: It was possible to reproduce anatomy of the skeletal structures, as well as through acquisitions of Magnetic Resonance Imaging; it was also possible to visualize the vascular, muscular, ligamentous and tendinous components of the articular complex, and also the capsule and the fibrous cartilaginous disc. We managed the Surface Rendering and Volume Rendering, not only to obtain three-dimensional images for colour and for resolution comparable to the usual anatomical preparations, but also a considerable number of anatomical, minuter details, zooming, rotating and cutting the same images with linking, graduating the colour, transparency and opacity from time to time.Conclusion: These results are encouraging to stimulate further studies in other anatomical districts.Background: The purpose of this study was to conduct a morphological analysis of the temporomandibular joint, a highly specialized synovial joint that permits movement and function of the mandible
A regional fish inventory of inland waters in Northern Italy reveals the presence of fully exotic fish communities
The aim of the study is to present a complete and updated fish inventory of inland waters of the Emilia-Romagna region, Northern Italy, and to highlight the presence of fully exotic fish communities. Overall, based on 208 sampling locations, the observed fish fauna consisted of 45 species, 22 native and 23 exotics. A significant element of the inventory is the identification of xenodiversity hotspots (spatially clustered sites, one lowland and one upland region), where a complete substitution of native species by exotic species was observed (in total seven sites in the lowland and two sites in the upland with no native species presence). These xenodiversity hotspots were found to host specific combinations of exotic species, which may be able to constitute balanced exotic communities. The hotspots of the lowland region are located in the northeast lowland part of the territory, hosting exotic species combinations mainly composed by wels catfish (Silurus glanis Linnaeus, 1758, a large predator), common carp (Cyprinus carpio Linnaeus, 1758, a large benthivore), crucian carp (Carassius spp., a small-bodied generalist) and other less dominant exotic species. The hotspots in the upland region were located in the southwest part of the territory and were dominated by only one exotic species (rainbow trout, Oncorhynchus mykiss (Walbaum, 1792)). A difference between these xenodiversity hotspots is that in the lowland the introductions were mostly unintentional and are not continued, while in the upland the introduction of rainbow trout is intentional and currently carried out by local fishermen
New insights into cortico-basal-cerebellar connectome: clinical and physiological considerations
The current model of the basal ganglia system based on the 'direct', 'indirect' and 'hyperdirect' pathways provides striking predictions about basal ganglia function that have been used to develop deep brain stimulation approaches for Parkinson's disease and dystonia. The aim of this review is to challenge this scheme in light of new tract tracing information that has recently become available from the human brain using MRI-based tractography, thus providing a novel perspective on the basal ganglia system. We also explore the implications of additional direct pathways running from cortex to basal ganglia and between basal ganglia and cerebellum in the pathophysiology of movement disorders
Folding mechanisms steer the amyloid fibril formation propensity of highly homologous proteins
Significant advances in the understanding of the molecular determinants of fibrillogenesis can be expected from comparative studies of the aggregation propensities of proteins with highly homologous structures but different folding pathways. Here, we fully characterize, by means of stopped-flow, T-jump, CD and DSC experiments, the unfolding mechanisms of three highly homologous proteins, zinc binding Ros87 and Ml153-149 and zinc-lacking Ml452-151. The results indicate that the three proteins significantly differ in terms of stability and (un)folding mechanisms. Particularly, Ros87 and Ml153-149 appear to be much more stable to guanidine denaturation and are characterized by folding mechanisms including the presence of an intermediate. On the other hand, metal lacking Ml452-151 folds according to a classic two-state model. Successively, we have monitored the capabilities of Ros87, Ml452-151 and Ml153-149 to form amyloid fibrils under native conditions. Particularly, we show, by CD, fluorescence, DLS, TEM and SEM experiments, that after 168 hours, amyloid formation of Ros87 has started, while Ml153-149 has formed only amorphous aggregates and Ml452-151 is still monomeric in solution. This study shows how metal binding can influence protein folding pathways and thereby control conformational accessibility to aggregation-prone states, which in turn changes aggregation kinetics, shedding light on the role of metal ions in the development of protein deposition diseases
The arterial blood supply of the temporomandibular joint: an anatomical study and clinical implications.
Purpose: The aim of this study was to analyze three-dimensional images of the arterial supply to the temporomandibular
joint.
Materials and Methods: Ten patients (five men and five women, mean age 36 years) without signs or symptoms of
temporomandibular disorders, who underwent contrast-enhanced computed tomographic (CT) scanning with
intravenous contrast, were studied. The direct volume rendering technique of CT images was used, and a data set of
images to visualize the vasculature of the human temporomandibular joint in three dimensions was created. After
elaboration of the data through post-processing, the arterial supply of the temporomandibular joint was studied.
Results: The analysis revealed the superficial temporal artery, the anterior tympanic artery, the deep temporal
artery, the auricular posterior artery, the transverse facial artery, the middle meningeal artery, and the maxillary
artery with their branches as the main arterial sources for the lateral and medial temporomandibular joint.
Conclusion: The direct volume rendering technique was found to be successful in the assessment of the arterial
supply to the temporomandibular joint. The superficial temporal artery and maxillary artery ran along the lateral
and medial sides of the condylar neck, suggesting that these arteries are at increased risk during soft-tissue procedures
such as an elective arthroplasty of the temporomandibular joint
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