3,654 research outputs found
High intensity X/ γ photon beams for nuclear physics and photonics
In this manuscript we review the challenges of Compton back-scattering sources in advancing photon beam performances in the1−20MeVenergy range, underlining the design criteria bringing tomaximum spectral luminosity and briefly describing the main achieve-ments in conceiving and developing new devices (multi-bunch RF cav-ities and Laser recirculators) for the case of ELI-NP Gamma BeamSystem (ELI-NP-GBS)
Negative group delay for Dirac particles traveling through a potential well
The properties of group delay for Dirac particles traveling through a
potential well are investigated. A necessary condition is put forward for the
group delay to be negative. It is shown that this negative group delay is
closely related to its anomalous dependence on the width of the potential well.
In order to demonstrate the validity of stationary-phase approach, numerical
simulations are made for Gaussian-shaped temporal wave packets. A restriction
to the potential-well's width is obtained that is necessary for the wave packet
to remain distortionless in the travelling. Numerical comparison shows that the
relativistic group delay is larger than its corresponding non-relativistic one.Comment: 10 pages, 5 figure
Clinical epigenetics settings for cancer and cardiovascular diseases: real-life applications of network medicine at the bedside
Despite impressive efforts invested in epigenetic research in the last 50 years, clinical applications are still lacking. Only a few university hospital centers currently use epigenetic biomarkers at the bedside. Moreover, the overall concept of precision medicine is not widely recognized in routine medical practice and the reductionist approach remains predominant in treating patients affected by major diseases such as cancer and cardiovascular diseases. By its’ very nature, epigenetics is integrative of genetic networks. The study of epigenetic biomarkers has led to the identification of numerous drugs with an increasingly significant role in clinical therapy especially of cancer patients. Here, we provide an overview of clinical epigenetics within the context of network analysis. We illustrate achievements to date and discuss how we can move from traditional medicine into the era of network medicine (NM), where pathway-informed molecular diagnostics will allow treatment selection following the paradigm of precision medicine
Resistive AC-Coupled Silicon Detectors: principles of operation and first results from a combined analysis of beam test and laser data
This paper presents the principles of operation of Resistive AC-Coupled
Silicon Detectors (RSDs) and measurements of the temporal and spatial
resolutions using a combined analysis of laser and beam test data. RSDs are a
new type of n-in-p silicon sensor based on the Low-Gain Avalanche Diode (LGAD)
technology, where the implant has been designed to be resistive, and the
read-out is obtained via AC-coupling. The truly innovative feature of RSD is
that the signal generated by an impinging particle is shared isotropically
among multiple read-out pads without the need for floating electrodes or an
external magnetic field. Careful tuning of the coupling oxide thickness and the
doping profile is at the basis of the successful functioning of this
device. Several RSD matrices with different pad width-pitch geometries have
been extensively tested with a laser setup in the Laboratory for Innovative
Silicon Sensors in Torino, while a smaller set of devices have been tested at
the Fermilab Test Beam Facility with a 120 GeV/c proton beam. The measured
spatial resolution ranges between for 70-100 pad-pitch geometry
and with 200-500 matrices, a factor of 10 better than what is
achievable in binary read-out (). Beam test data show a
temporal resolution of for 200- pitch devices, in line
with the best performances of LGAD sensors at the same gain.Comment: 34 pages, 33 figure
Building the Largest Spectroscopic Sample of Ultracompact Massive Galaxies with the Kilo Degree Survey
Ultracompact massive galaxies (ucmgs), i.e., galaxies with stellar masses M∗ > 8× 10-10 M⊙ and effective radii R e< 1.5 kpc, are very rare systems, in particular at low and intermediate redshifts. Their origin as well as their number density across cosmic time are still under scrutiny, especially because of the paucity of spectroscopically confirmed samples. We have started a systematic census of ucmg candidates within the ESO Kilo Degree Survey, together with a large spectroscopic follow-up campaign to build the largest possible sample of confirmed ucmgs. This is the third paper of the series and the second based on the spectroscopic follow-up program. Here, we present photometrical and structural parameters of 33 new candidates at redshifts 0.15≲ z≲ 0.5 and confirm 19 of them as ucmgs, based on their nominal spectroscopically inferred M and R e. This corresponds to a success rate of ∼ 58%, nicely consistent with our previous findings. The addition of these 19 newly confirmed objects allows us to fully assess the systematics on the system selection-and to finally reduce the number density uncertainties. Moreover, putting together the results from our current and past observational campaigns and some literature data, we build the largest sample of ucmgs ever collected, comprising 92 spectroscopically confirmed objects at 0.1≲ z≲ 0.5. This number raises to 116, allowing for a 3σ tolerance on the M∗ and Re thresholds for the ucmg definition. For all these galaxies, we have estimated the velocity dispersion values at the effective radii, which have been used to derive a preliminary mass-velocity dispersion correlation
KiDS ultracompact massive galaxies sp. obs.
Ultracompact massive galaxies (UCMGs), i.e., galaxies with stellar masses M*>8x1010M☉ and effective radii Re<1.5kpc, are very rare systems, in particular at low and intermediate redshifts. Their origin as well as their number density across cosmic time are still under scrutiny, especially because of the paucity of spectroscopically confirmed samples. We have started a systematic census of UCMG candidates within the ESO Kilo Degree Survey, together with a large spectroscopic follow-up campaign to build the largest possible sample of confirmed UCMGs. This is the third paper of the series and the second based on the spectroscopic follow-up program. Here, we present photometrical and structural parameters of 33 new candidates at redshifts 0.15≲z≲0.5 and confirm 19 of them as UCMGs, based on their nominal spectroscopically inferred M* and Re. This corresponds to a success rate of ∼58% , nicely consistent with our previous findings. The addition of these 19 newly confirmed objects allows us to fully assess the systematics on the system selection-and to finally reduce the number density uncertainties. Moreover, putting together the results from our current and past observational campaigns and some literature data, we build the largest sample of ucmgs ever collected, comprising 92 spectroscopically confirmed objects at 0.1≲z≲0.5. This number raises to 116, allowing for a 3σ tolerance on the M* and Re thresholds for the ucmg definition. For all these galaxies, we have estimated the velocity dispersion values at the effective radii, which have been used to derive a preliminary mass-velocity dispersion correlation
Critical Review of Theoretical Models for Anomalous Effects (Cold Fusion) in Deuterated Metals
We briefly summarize the reported anomalous effects in deuterated metals at
ambient temperature, commonly known as "Cold Fusion" (CF), with an emphasis on
important experiments as well as the theoretical basis for the opposition to
interpreting them as cold fusion. Then we critically examine more than 25
theoretical models for CF, including unusual nuclear and exotic chemical
hypotheses. We conclude that they do not explain the data.Comment: 51 pages, 4 Figure
Potential conservation of circadian clock proteins in the phylum Nematoda as revealed by bioinformatic searches
Although several circadian rhythms have been described in C. elegans, its molecular clock remains elusive. In this work we employed a novel bioinformatic approach, applying probabilistic methodologies, to search for circadian clock proteins of several of the best studied circadian model organisms of different taxa (Mus musculus, Drosophila melanogaster, Neurospora crassa, Arabidopsis thaliana and Synechoccocus elongatus) in the proteomes of C. elegans and other members of the phylum Nematoda. With this approach we found that the Nematoda contain proteins most related to the core and accessory proteins of the insect and mammalian clocks, which provide new insights into the nematode clock and the evolution of the circadian system.Fil: Romanowski, Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; ArgentinaFil: Garavaglia, Matías Javier. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Ing.genética y Biolog.molecular y Celular. Area Virus de Insectos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Goya, María Eugenia. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ghiringhelli, Pablo Daniel. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Ing.genética y Biolog.molecular y Celular. Area Virus de Insectos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Golombek, Diego Andres. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Search for Neutral Higgs Bosons in Events with Multiple Bottom Quarks at the Tevatron
The combination of searches performed by the CDF and D0 collaborations at the
Fermilab Tevatron Collider for neutral Higgs bosons produced in association
with b quarks is reported. The data, corresponding to 2.6 fb-1 of integrated
luminosity at CDF and 5.2 fb-1 at D0, have been collected in final states
containing three or more b jets. Upper limits are set on the cross section
multiplied by the branching ratio varying between 44 pb and 0.7 pb in the Higgs
boson mass range 90 to 300 GeV, assuming production of a narrow scalar boson.
Significant enhancements to the production of Higgs bosons can be found in
theories beyond the standard model, for example in supersymmetry. The results
are interpreted as upper limits in the parameter space of the minimal
supersymmetric standard model in a benchmark scenario favoring this decay mode.Comment: 10 pages, 2 figure
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