Directional detection of Dark Matter (DM) particles could be accomplished by studying either ion or electron recoils in large arrays of parallel carbon nanotubes (CNT). For instance, a MeV mass DM ...particle could scatter off a lattice electron, resulting in the transfer of sufficient energy to eject the electron from the CNT surface. The electron can eventually be detected whenever an external electric field is added to drive it from the open ends of the array. This detection scheme would offer an anisotropic response and could be used to select an orientation of the target with respect to the DM wind. A compact sensor, in which the cathode element is substituted with a dense array of parallel CNT, could serve as the basic detection unit which - if adequately replicated - would allow to explore a significant region of light DM mass and cross-section. A similar detection scheme could be used to detect DM particles with mass in the GeV range scattering off the surface of a CNT and ejecting a carbon ion. We report about the Monte Carlo simulations of such a system and the R&D towards a detector prototype.
Olive oil contains many different compounds which are responsible for its nutritional and sensorial value. However, some compounds present in olive oil at very low amounts have not yet been ...identified. Here, the detection of tetrahydrogeranylgeraniol and dihydrogeranylgeraniol, in both the total aliphatic alcohol and waxy fractions of extra virgin olive oil, is reported for the first time using GC and GC-MS methodologies. It was suggested that tetrahydrogeranylgeraniol and dihydrogeranylgeraniol do not originate from the hydrolysis of the chlorophyll but are present as diterpenic esters.
Abstract
Novel particle accelerators based on plasma technology allow a drastic reduction in size, due to the high accelerating field established inside plasmas, which are created and confined by ...specific devices. Plasma Wakefield Acceleration experiments are performed at the SPARC_LAB test facility (Laboratori Nazionali di Frascati - INFN) by using gas-filled capillaries, in which the plasma formation is achieved by ionizing hydrogen gas through high voltage pulses. In this work, the characterization of gas-filled plasma-discharge capillaries is presented. Several geometrical configurations are tested, including capillaries with different channel shapes and arrangement of inlets positions for the gas injection. Such configurations are designed in order to enhance the uniformity of the plasma density distribution along the plasma channel, which is necessary to improve particle beam acceleration. Plasma sources are characterized by means of the spectroscopic technique based on the Stark broadening method, which allows to measure the evolution of the plasma density profile along the channel. In addition, the CFD software OpenFoam is used to simulate the dynamics of the neutral gas during the filling of the capillary.
Background
Reports of histiocytic sarcoma (HS) involving the central nervous system (CNS) are sparse and consist mainly of case reports describing 1–3 animals.
Objective
The objective of this study ...was to report the signalments, clinical signs, clinicopathologic and diagnostic imaging findings, treatment, and outcome of a series of dogs with HS and CNS involvement.
Animals
Nineteen dogs with HS examined at veterinary referral hospitals.
Methods
Retrospective case series. Medical records were reviewed and cases with a histopathological diagnosis of CNS HS were included in the study. Diagnostic imaging studies of the CNS were evaluated and histopathologic samples were reviewed to confirm the diagnosis.
Results
Retrievers and Pembroke Welsh Corgis were overrepresented in this cohort of dogs. Tumors involved the brain in 14 dogs and the spinal cord in 5. In 4 dogs, HS was part of a disseminated, multiorgan process whereas it appeared confined to the CNS in 15 dogs. Diagnostic imaging had variable appearances although extraaxial masses predominated in the brain. There was meningeal enhancement in all dogs that was often profound and remote from the primary mass lesion. Pleocytosis was present in all dogs with CSF evaluation. Median survival was 3 days.
Conclusions and Clinical Importance
Breed predispositions appear to vary from reports of HS in other organ systems. Some unique imaging and clinicopathologic characteristics, particularly brain herniation, profound meningeal enhancement, and pleocytosis in combination with 1 or more mass lesions, might help to differentiate this neoplasm from others involving the CNS, although this requires further study.
The search in two-dimensional condensed matter systems of Rashba-type spin-polarized electronic states is aimed by the possibility to control and manipulate the spin orientation. In this Letter, for ...the first time, we report on the experimental evidence of a Rashba-type spin splitting in the n=1 image potential state. The image potential state Rashba splitting here measured at the graphene/Ir(111) interface, as confirmed by theoretical considerations, can be detectable to any metal surface with a significant spin-orbit coupling.
We propose to experimentally study, in cylindrical geometry, the interaction of an initially perturbed cylindrical gaseous interface with a converging shock wave. This interaction is commonly ...referred as the Richtmyer–Meshkov instability (RMI) which, in the present case, is in a cylindrical geometry. In order to achieve this goal, we use a conventional shock tube which is adapted to this geometry through a specifically designed convergent test section. Here, the first results are presented for an incident planar shock wave of Mach number 1.15 propagating through an adequately elliptical
air
/
SF
6
interface. It curves into a cylindrical transmitted shock wave and then accelerates a second sinusoidally perturbed
SF
6
/air interface. From analyzing schlieren photos and pressure histories, we validate this original approach and exhibit the great potential of this experimental method for studying the RMI induced by focusing shock waves.
The purpose of the present study was to characterize the development of Listeria monocytogenes on wooden shelves used for cheese ripening. The fate of two L. monocytogenes strains was analysed over ...time as a function of the presence of a native biofilm, the farmhouse origin of cheeses, and the wooden shelves properties. In presence of a native microbial flora on the shelves, deposited populations of L. monocytogenes remained stable or even decreased by up to 2 log10(CFU/cm2) after 12 days of incubation at 15 °C in all tested conditions. By contrast, L. monocytogenes populations increased by up to 4 log10(CFU/cm2) when the resident biofilm was thermally inactivated, suggesting a microbial origin of the observed inhibitory effect. All together, our results suggest that the biocontrol of pathogens multiplication on wooden shelves by resident biofilms should be considered for the microbiological safety of traditional ripened cheeses.
Giant reed (Arundo donax) is a promising energy crop of the Mediterranean areas. It has long been associated with humans and has been cultivated in Asia, southern Europe, North Africa and the Middle ...East for thousands of years. It is a perennial herbaceous plant (Poaceae) found in grasslands and wetlands throughout a wide range of climatic zones. Amplified fragment length polymorphism (AFLP) analysis was used to assess genetic inter and intrarelationships between A. donax and other Arundo species. Furthermore, the development of the sexual apparatus was analysed to understand the basis of sterility in the accession examined. The dendrograms obtained by phenetic and cladistic analysis support the monophyletic origin of giant reed and suggest that it originated in Asia and began to spread into the Mediterranean without traces of hybridisation with the other Arundo species. In particular, samples from Mediterranean areas are characterisd by a lower gene diversity and incidence of rare AFLP fragments indicating that these populations are recent in origin. Moreover, results indicate the occurrence of post-meiotic alterations in the ovule and pollen developmental pathway. Thus, the success of giant reed can be attributed mainly to its rapid clonal spread by rhizome extension, flood dispersal of rhizome and culm fragments.
In this work, we have analyzed data sets from various fields using a coupled Ornstein–Uhlenbeck (OU) system of equations driven by Lévy processes. The Ornstein–Uhlenbeck model is well known for its ...ability to capture stochastic behaviors when used as a predictive model. There’s empirical evidence showing that there exist dependencies or correlations between events; thus, we may be able to model them together. Here we show such correlation between data from finance, geophysics and health as well as show the predictive performance when they are modeled with a coupled Ornstein–Uhlenbeck system of equations. The results show that the solution to the stochastic system provides a good fit to the data sets analyzed. In addition by comparing the results obtained when the BDLP is a Γ(a,b) process or an IG(a,b) process, we are able to deduce the best choice out of the two to model our data sets.
A new approach to the geographical characterisation of virgin olive oils (VOOs) based on the
1H NMR fingerprint of the unsaponifiable matter is presented. The
1H NMR spectra of the unsaponifiable ...fraction of virgin olive oils from Spain, Italy, Greece, Tunisia, Turkey, and Syria were analysed by several pattern recognition techniques (LDA, PLS-DA, SIMCA, and CART). PLS-DA (PLS-1 approach) obtained the best classification results for all classes. Moreover,
1H NMR spectra of the bulk oil, and its corresponding unsaponifiable fraction, as well as the subfractions of the unsaponifiable fraction (alcohol, sterol, hydrocarbon, and tocopherol fractions) were studied in the search for the markers that multivariate techniques revealed to be related to the geographical origin of olive oils. Additionally, a preliminary study regarding
1H NMR data of the bulk oil and the corresponding unsaponifiable fraction of VOOs suggested that these spectral data contained complementary information for the geographical characterisation of VOOs.
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