3,052 research outputs found
The Strongly-Interacting Light Higgs
We develop a simple description of models where electroweak symmetry breaking
is triggered by a light composite Higgs, which emerges from a
strongly-interacting sector as a pseudo-Goldstone boson. Two parameters broadly
characterize these models: m_rho, the mass scale of the new resonances and
g_rho, their coupling. An effective low-energy Lagrangian approach proves to be
useful for LHC and ILC phenomenology below the scale m_rho. We identify two
classes of operators: those that are genuinely sensitive to the new strong
force and those that are sensitive to the spectrum of the resonances only.
Phenomenological prospects for the LHC and the ILC include the study of
high-energy longitudinal vector boson scattering, strong double-Higgs
production and anomalous Higgs couplings. We finally discuss the possibility
that the top quark could also be a composite object of the strong sector.Comment: 45 pages, 1 figure. v2: references adde
Probing Split Supersymmetry with Cosmic Rays
A striking aspect of the recently proposed split supersymmetry is the
existence of heavy gluinos which are metastable because of the very heavy
squarks which mediate their decay. In this paper we correlate the expected flux
of these particles with the accompanying neutrino flux produced in inelastic
collisions in distant astrophysical sources. We show that an event rate at
the Pierre Auger Observatory of approximately 1 yr for gluino masses of
about 500 GeV is consistent with existing limits on neutrino fluxes. The
extremely low inelasticity of the gluino-containing hadrons in their collisions
with the air molecules makes possible a distinct characterization of the
showers induced in the atmosphere. Should such anomalous events be observed, we
show that their cosmogenic origin, in concert with the requirement that they
reach the Earth before decay, leads to a lower bound on their proper lifetime
of the order of 100 years, and consequently, to a lower bound on the scale of
supersymmetry breaking, GeV. Obtaining
such a bound is not possible in collider experiments.Comment: Version to be published in Phys. Rev.
Brane Cosmology and KK Gravitinos
The cosmology of KK gravitinos in models with extra dimensions is considered.
The main result is that the production of such KK modes is not compatible with
an epoch of non--standard expansion after inflation. This is so because the BBN
constraint on the zero mode forces the reduced five dimensional Planck mass
down to values much smaller than the usual four dimensional one, but this
in turn implies many KK states available for a given temperature. Once these
states are taken into account one finds that there is no for which the
produced KK gravitinos satisfy BBN and overclosure constraints. This conclusion
holds for both flat and warped models in which only gravity propagates in the
full spacetime.Comment: 19 pages, references added, IoP styl
Radiative seesaw and degenerate neutrinos
The radiative see-saw mechanism of Witten generates the right-handed neutrino
masses in SO(10) with the spinorial 16_H Higgs field. We study here
analytically the 2nd and 3rd generations for the minimal Yukawa structure
containing 10_H and 120_H Higgs representations. In the approximation of small
2nd generation masses and gauge loop domination we find the following results :
(1) b-tau unification, (2) natural coexistence between large theta_l and small
theta_q, (3) degenerate neutrinos.Comment: 4 page
comparison between thermal energy and acoustic emission for the fatigue behavior of steels
Abstract The paper is focused on the study of fatigue materials, using an energy approach, with the support of two different non-destructive techniques. Indeed, the analysis of the energy behavior was conducted by the simultaneous application of Acoustic Emission (AE) and Thermography (TH). The purpose of the paper was to compare and integrate the results obtained by the two methodologies to assess the fatigue behavior of materials. The experimental tests were carried out on flat steel specimens of steels commonly used for metal carpentry either under static loading or under sequences of increasing cyclic loading. The results allow to define the fatigue limit either by the thermography or by the acoustic emission and they are encouraging to continue the comparison and the integration between the two energetic methodologies
Serum protein electrophoresis pro le during late pregnancy and early post partum period in mares
The aim of the study was to determine how the physiological adjustments occurring during late pregnancy and the early post partum period affect mares’ serum protein profile. Ten pregnant mares (Group A) were monitored from the 34th week of pregnancy until the 3rd week after foaling, ten nonpregnant mares (Group B) were used as the control. Blood samples were collected every 3 weeks, from -16 to -4 weeks preceding parturition, and then every week until the 3rd week after foaling. Additional blood samples were taken within 24±12 h from foaling. The statistical analysis revealed a significant increase in albumin and α2-globulin concentrations obtained from Group A during the experimental period. Dunnet’s test also revealed significantly higher concentrations of α1-globulins, α2-globulins and γ-globulins in group A than in group B. The following results showed that the serum proteins differed in periparturient mares when compared to non-pregnant mares and significant changes in some protein fractions occurred over the experimental period. Focusing on the peripartum period, our study provides specific information about mare’s serum protein profile that could help equine practitioners to better interpret clinical data and promptly diagnose pathological conditions that might compromise the health status of the mare and, as consequence, also her foal
The peripartum period influenced the serum macromineral profile in mares
Changes in metabolic requirements during pregnancy may produce nutritional imbalances predisposing mares to pathological conditions. Therefore, we aimed to examine changes in serum macrominerals during the peripartum period in mares. Fifteen pregnant mares (Group A) were monitored starting at the 263rd day of pregnancy until the 21st day after foaling. Seven non-pregnant and non-lactating mares were used as a control group (Group B). Group A was subjected to blood sampling within 24-12 h after parturition (P) and then 7, 14 and 21 days after foaling (C1, C2, C3 weeks, respectively). Group B was subjected to regular sampling throughout the study to ensure that seasonal changes had no significant effect on studied parameters. Serum samples were analysed for serum electrolytes including sodium (NaC), potassium (KC), calcium (CaCC), phosphorus (PC), chloride (Cl) and magnesium (MgCC). Two-way repeated measures of analysis of variance (ANOVA) was applied to evaluate significant effects of peripartum on electrolyte concentrations. Group A showed a decrease in Cl concentrations (P D 0:011) after foaling and lower PC concentrations (P D 0:015) compared to Group B throughout the study. The linear regression model showed an increase in NaC concentrations (P D 0:002) and a gradual decrease in serum CaCC (P D 0:001) during pregnancy. Because the most significant changes in serum electrolytes occurred within 2 weeks before and 2 weeks after foaling, monitoring serum electrolyte concentrations would indicate whether the mare needs further mineral supplementation at this stage. The significant changes in a mare's macromineral profile that we observed over the peripartum provide enhanced knowledge about mineral interrelations and their modifications during specific physiological conditions such as late pregnancy and early postpartum
Widespread extrahepatic expression of acute-phase proteins in healthy chicken (Gallus gallus) tissues
Acute phase proteins (APP) are plasma proteins that can modify their expression in response to inflammation caused by tissue injury, infections, immunological disorders or stress. Although APP are produced mainly in liver, extrahepatic production has also been described. As a prerequisite to get insight the expression of APP in chicken during diseases, this study investigated the presence of five APP, including alpha1-acid glycoprotein (AGP), Serum Amyloid A (SAA), PIT54, C-Reactive protein (CRP) and Ovotransferrin (OVT) in twenty tissues collected from healthy chicken (Gallus gallus) by quantitative Real Time PCR and immunohistochemistry. As expected, APP gene abundance was higher in liver compared with other tissues. The mRNA coding for CRP, OVT and SAA was detected in all analyzed tissues with a higher expression in gastrointestinal tract, respiratory and lymphatic samples. SAA expression was particularly high in cecal tonsil, lung, spleen and Meckel's diverticulum, whereas OVT in lung, bursa of Fabricius and pancreas. AGP and PIT54 mRNA expression were detected in all tissues but at negligible levels. Immunohistochemical expression of AGP and OVT was variably detected in different organs, being identified in endothelium of every tissue. Positive cells were present in the epithelium of the mucosal layer of gastrointestinal tract and kidney. Lung and central nervous system stained for both proteins. No positive staining was detected in lymphoid tissues and muscle. These results suggest that most tissues can express different amount of APP even in healthy conditions and are therefore capable to mount a local acute phase reaction
Photocurrent study of beta-ray priming in CVD diamond
Priming by X-rays or by beta-rays is generally needed in order to qualify CVD diamond for nuclear detection or for dosimetry. The priming effect is usually attributed in filling the hole traps, which are responsible for the charge collection efficiency of the detector. Emptying the filled traps can be easily detected by Thermoluminescence (TL), which is considered to be a measure of the absorbed dose. In this work, we prove that below-gap photocurrent (BGPC) can also be used in the same way and it is dominated by the optical detrapping of holes from the same centers. Time dependence of this beta-rays induced persistent photocurrent (PPC), which in fact, depends only on the total number of photons impinging onto the sample. In fact, at long times or for large number of photons, the photocurrent approaches to the same limit of PC for a null dose. The hole trapping centers distribution seems to extend from 1.25 to 2.5 eV valence band
COVID-19 Pneumonia in Children: From Etiology to Management
COVID-19 is less serious in children than in adults. However, respiratory management dominates the clinical picture of hospitalized COVID-19 even in children. In some case series, deterioration of the clinical picture wherein dyspnea, cyanosis, and the onset of acute respiratory distress syndrome (ARDS) emerged ~8–10 days after the onset of SARS-CoV-2 infection, which could rapidly progress to multiple organ failure and death. This review aimed to evaluate the characteristics of COVID-19 pneumonia in pediatric populations, beginning from its etiology and pathological mechanisms and closing with its clinical management
- …