2,096 research outputs found
Fourth Lepton Family is Natural in Technicolor
Imagine to discover a new fourth family of leptons at the Large Hadron
Collider (LHC) but no signs of an associated fourth family of quarks. What
would that imply? An intriguing possibility is that the new fermions needed to
compensate for the new leptons gauge anomalies simultaneously address the big
hierarchy problem of the Standard Model. A natural way to accomplish such a
scenario is to have the Higgs itself be composite of these new fermions. This
is the setup we are going to investigate in this paper using as a template
Minimal Walking Technicolor. We analyze a general heavy neutrino mass structure
with and without mixing with the Standard Model families. We also analyze the
LHC potential to observe the fourth lepton family in tandem with the new
composite Higgs dynamics. We finally introduce a model uniting the fourth
lepton family and the technifermion sector at higher energies.Comment: 39 ReVTeX pages, 16 figure
Hints of a Charge Asymmetry in the Electron and Positron Cosmic-Ray Excesses
By combining the recent data from AMS-02 with those from Fermi-LAT, we show
the emergence of a charge asymmetry in the electron and positron cosmic-ray
excesses, slightly favoring the electron component. Astrophysical and dark
matter inspired models introduced to explain the observed excesses can be
classified according to their prediction for the charge asymmetry and its
energy dependence. Future data confirming the presence of a charge asymmetry,
would imply that an asymmetric production mechanism is at play.Comment: v1: 15 pages, 5 figures; v2: 15 pages, 5 figures, text and references
improved, published versio
Metabotropic glutamate 2/3 receptors and epigenetic modifications in psychotic disorders: a review
Schizophrenia and Bipolar Disorder are chronic psychiatric disorders, both considered as "major psychosis"; they are thought to share some pathogenetic factors involving a dysfunctional gene x environment interaction. Alterations in the glutamatergic transmission have been suggested to be involved in the pathogenesis of psychosis. Our group developed an epigenetic model of schizophrenia originated by Prenatal Restraint Stress (PRS) paradigm in mice. PRS mice developed some behavioral alterations observed in schizophrenic patients and classic animal models of schizophrenia, i.e. deficits in social interaction, locomotor activity and prepulse inhibition. They also showed specific changes in promoter DNA methylation activity of genes related to schizophrenia such as reelin, BDNF and GAD67, and altered expression and function of mGlu2/3 receptors in the frontal cortex. Interestingly, behavioral and molecular alterations were reversed by treatment with mGlu2/3 agonists. Based on these findings, we speculate that pharmacological modulation of these receptors could have a great impact on early phase treatment of psychosis together with the possibility to modulate specific epigenetic key protein involved in the development of psychosis. In this review, we will discuss in more details the specific features of the PRS mice as a suitable epigenetic model for major psychosis. We will then focus on key proteins of chromatin remodeling machinery as potential target for new pharmacological treatment through the activation of metabotropic glutamate receptors
Evaluation of the relationships between computed tomography features, pathological findings, and rrognostic risk assessment in gastrointestinal stromal tumors
Objectives The aim of this study was to correlate computed tomography (CT) findings with pathology in gastrointestinal stromal tumors (GISTs). Methods A retrospective evaluation of CT images of 44 patients with GISTs was performed. Computed tomography findings analyzed were location, size, margins, degree and pattern of contrast enhancement, angiogenesis, necrosis, signs of invasion, peritoneal effusion, peritoneal implants, surface ulceration, and calcifications. Associations between CT features and mitotic rate, Miettinen classes of risk, lesions size, and among CT features were investigated. χ 2 Test and Fisher test were performed. Results Mitotic rate was associated with margins (P = 0.016) and with adjacent organ invasion (P = 0.043). Pattern of contrast enhancement (P = 0.002), angiogenesis (P = 0.006), necrosis (P = 0.006), invasion of adjacent organs (P = 0.011), and margins (P = 0.006) were associated with classes of risk. Several associations (P < 0.05) between lesion size and CT features and among all the investigated CT features were found. Conclusions Computed tomography features could reflect GIST biology being associated with the mitotic rate and with classes of risk
Notch and NF-kB: Coach and Players of Regulatory T-Cell Resposnse in Cancer
The Notch signaling pathway plays multiple roles in driving T-cell fate decisions,
proliferation, and aberrant growth. NF-kB is a cell-context key player interconnected
with Notch signaling either in physiological or in pathological conditions. This review
focuses on how themultilayered crosstalk between different Notches and NF-kB subunits
may converge on Foxp3 gene regulation and orchestrate CD4+ regulatory T (Treg)
cell function, particularly in a tumor microenvironment. Notably, Treg cells may play a
pivotal role in the inhibition of antitumor immune responses, possibly promoting tumor
growth. A future challenge is represented by further dissection of both Notch and NF-kB
pathways and consequences of their intersection in tumor-associated Treg biology. This
may shed light on themolecularmechanisms regulating Treg cell expansion andmigration
to peripheral lymphoid organs thought to facilitate tumor development and still to be
explored. In so doing, new opportunities for combined and/or more selective therapeutic
Q25 approaches to improve anticancer immunity may be found
TOSC: an algorithm for the tomography of spotted transit chords
Photometric observations of planetary transits may show localized bumps,
called transit anomalies, due to the possible crossing of photospheric
starspots. The aim of this work is to analyze the transit anomalies and derive
the temperature profile inside the transit belt along the transit direction. We
develop the algorithm TOSC, a tomographic inverse-approach tool which, by means
of simple algebra, reconstructs the flux distribution along the transit belt.
We test TOSC against some simulated scenarios. We find that TOSC provides
robust results for light curves with photometric accuracies better than 1~mmag,
returning the spot-photosphere temperature contrast with an accuracy better
than 100~K. TOSC is also robust against the presence of unocculted spots,
provided that the apparent planetary radius given by the fit of the transit
light curve is used in place of the true radius. The analysis of real data with
TOSC returns results consistent with previous studies
Cosmic Sum Rules
We introduce new sum rules allowing to determine universal properties of the
unknown component of the cosmic rays and show how they can be used to predict
the positron fraction at energies not yet explored by current experiments and
to constrain specific models.Comment: RevTeX, 4 pages, 6 figures, two-columns. Final version to match the
published version in Brief Reports section of Phys. Rev. D. We stress that
this is the first paper about charge asymmetries in cosmic ray
High-performance yellow ceramic pigments Zr(Ti1-x-ySnx-yVyMy)O4 (M = Al, In, Y): crystal structure, colouring mechanism and technological properties
Zirconium titanate-stannate doped with V with co-dopants Al, In or Y was synthesised by solid state reaction and its structural (XRD, SEM), optical (DRS) and technological properties were determined to assess its potential use as ceramic pigment. These compounds have a srilankite-type, disordered orthorhombic structure, implying a random distribution of Zr, Ti, Sn and dopants in a single, strongly distorted octahedral site. Doping caused an increase of unit-cell dimensions, metal-oxygen distances and octahedron distortion. Optical spectra show crystal field electronic transitions of V4+ as well as intense bands in the blue-UV range due to V4+-V5+ intervalence charge transfer and/or to V-O charge transfer. The formation of oxygen vacancies is supposed to compensate the occurrence of V4+ ensuring the lattice charge neutrality. These srilankite-type oxides develop a deep and brilliant yellow shade with colourimetric parameters close to those of industrial ceramic pigments. Technological tests in several ceramic applications proved that zirconium titanate-stannate is very stable at high temperature, exhibiting an excellent performance in the 1200-1250?C range, even better than praseodymium-doped zircon
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