Applications of Graphene at Microwave Frequencies

In view to the epochal scenarios that nanotechnology discloses, nano-electronics has the potential to introduce a paradigm shift in electronic systems design similar to that of the transition from vacuum tubes to semiconductor devices. Since low dimensional (1D and 2D) nano-structured materials exhibit unprecedented electro-mechanical properties in a wide frequency range, including radio-frequencies (RF), microwave nano-electronics provides an enormous and yet widely undiscovered opportunity for the engineering community. Carbon nano-electronics is one of the main research routes of RF/microwave nano-electronics. In particular, graphene has shown proven results as an emblematic protagonist, and a real solution for a wide variety of microwave electronic devices and circuits. This paper introduces graphene properties in the microwave range, and presents a paradigm of novel graphene-based devices and applications in the microwave/RF frequency range

Transverse-momentum resummation and the spectrum of the Higgs boson at the LHC

We consider the transverse-momentum (q_T) distribution of generic high-mass systems (lepton pairs, vector bosons, Higgs particles, ....) produced in hadron collisions. At small q_T, we concentrate on the all-order resummation of the logarithmically-enhanced contributions in QCD perturbation theory. We elaborate on the $b$-space resummation formalism and introduce some novel features: the large logarithmic contributions are systematically exponentiated in a process-independent form and, after integration over q_T, they are constrained by perturbative unitarity to give a vanishing contribution to the total cross section. At intermediate and large q_T, resummation is consistently combined with fixed-order perturbative results, to obtain predictions with uniform theoretical accuracy over the entire range of transverse momenta. The formalism is applied to Standard Model Higgs boson production at LHC energies. We combine the most advanced perturbative information available at present for this process: resummation up to next-to-next-to-leading logarithmic accuracy and fixed-order perturbation theory up to next-to-leading order. The results show a high stability with respect to perturbative QCD uncertainties.Comment: 48 pages, 13 postscript figure

Threshold Effects in Slepton-Pair Production at the LHC

We present a study of threshold resummation effects for slepton pair production at the Large Hadron Collider (LHC). After confirming the known NLO QCD corrections and generalizing the NLO SUSY-QCD corrections to the case of mixing squarks in the virtual loop contributions, we employ the Mellin N-space resummation formalism to compute logarithmically enhanced soft-gluon terms to all perturbative orders.Comment: 3 pages, 1 figure, presented at HEP 2007 (Manchester, July 2007

Z\gamma\gamma production with leptonic decays and triple photon production at NLO QCD

We present a calculation of the O(alpha_s) QCD corrections to the production of a Z boson in association with two photons and to triple photon production at hadron colliders. All final-state photons are taken as real. For the Z boson, we consider the decays both into charged leptons and into neutrinos including all off-shell effects. Numerical results are obtained via a Monte Carlo program based on the structure of the VBFNLO program package. This allows us to implement general cuts and distributions of the final-state particles. We find that the NLO QCD corrections are sizable and significantly exceed the expectations from a scale variation of the leading-order result. In addition, differential distributions of important observables change considerably. The prediction of two-photon-associated Z production with Z decays into neutrinos from the charged-lepton rate works well, once we use an additional cut on the invariant mass of the charged-lepton pair.Comment: 14 pages, 10 figures, 2 table

Investigation of metal flow in bridge die extrusion of Alloy 6063 and subsequent effect on surface quality and weld seam integrity

This paper describes a detailed study of tube extrusion by simulation using finite element method (FEM). The finite element model used one-sixth of symmetry. The extrusion load, emperature evolution and metal flow were predicted. Innovative methods, combining both grid and surface tools, were used to define in detail the flow of material. These showed clearly the inner and outer surface formation mechanisms of the tube extrusion. The seam weld, an important quality indicator, was also evaluated by selecting an appropriate criterion

The Chemokine CCL2 Mediates the Seizure-enhancing Effects of Systemic Inflammation

Epilepsy is a chronic disorder characterized by spontaneous recurrent seizures. Brain inflammation is increasingly recognized as a critical factor for seizure precipitation, but the molecular mediators of such proconvulsant effects are only partly understood. The chemokine CCL2 is one of the most elevated inflammatory mediators in patients with pharmacoresistent epilepsy, but its contribution to seizure generation remains unexplored. Here, we show, for the first time, a crucial role for CCL2 and its receptor CCR2 in seizure control. We imposed a systemic inflammatory challenge via lipopolysaccharide (LPS) administration in mice with mesial temporal lobe epilepsy. We found that LPS dramatically increased seizure frequency and upregulated the expression of many inflammatory proteins, including CCL2. To test the proconvulsant role of CCL2, we administered systemically either a CCL2 transcription inhibitor (bindarit) or a selective antagonist of the CCR2 receptor (RS102895). We found that interference with CCL2 signaling potently suppressed LPS-induced seizures. Intracerebral administration of anti-CCL2 antibodies also abrogated LPS-mediated seizure enhancement in chronically epileptic animals. Our results reveal that CCL2 is a key mediator in the molecular pathways that link peripheral inflammation with neuronal hyperexcitability

Vector boson production at hadron colliders: hard-collinear coefficients at the NNLO

We consider QCD radiative corrections to vector-boson production in hadron collisions. We present the next-to-next-to-leading order (NNLO) result of the hard-collinear coefficient function for the all-order resummation of logarithmically-enhanced contributions at small transverse momenta. The coefficient function controls NNLO contributions in resummed calculations at full next-to-next-to-leading logarithmic accuracy. The same coefficient function is used in applications of the subtraction method to perform fully-exclusive perturbative calculations up to NNLO.Comment: 13, pages, no figures. arXiv admin note: text overlap with arXiv:1106.465

Gaugino production in proton-proton collisions at a center-of-mass energy of 8 TeV

Motivated by hints for a light Standard Model-like Higgs boson and a shift in experimental attention towards electroweak supersymmetry particle production at the CERN LHC, we update in this paper our precision predictions at next-to-leading order of perturbative QCD matched to resummation at the next-to-leading logarithmic accuracy for direct gaugino pair production in proton-proton collisions with a center-of-mass energy of 8 TeV. Tables of total cross sections are presented together with the corresponding scale and parton density uncertainties for benchmark points adopted recently by the experimental collaborations, and figures are presented for up-to-date model lines attached to them. Since the experimental analyses are currently obtained with parton showers matched to multi-parton matrix elements, we also analyze the precision of this procedure by comparing invariant-mass and transverse-momentum distributions obtained in this way to those obtained with threshold and transverse-momentum resummation.Comment: 28 pages, 7 figures, 9 tables; version to appear in JHE

Evolution of productive and biodiversity features in lucerne fields of different ages

Received: January 10th, 2022 ; Accepted: February 23rd, 2022 ; Published: April 1st, 2022 ; Correspondence: [email protected] sativa is a legume forage crop characterized by high production of forage, with a notable nutritive value, but in mountain areas duration of the crop could be remarkably affected by severe environmental conditions. To assess the vegetation evolution of lucerne crops in relation to crop age, data from fields of lucerne of different ages were collected. The aim is the evaluation of lucerne productive performances, evolution of forage quality and assessment of recovery by autochthonous species that naturally recolonize the studied areas in relation to age of the cropped species. With increasing years, lucerne population was significantly decreased and replaced by different functional types of plants, such as perennial graminoids and short-lived forbs. Biodiversity increased significantly along time, and evolution of similarity indices demonstrated an evolution of vegetation toward that represented by reference grassland of the area. Productive characteristics of forage, in terms of aboveground biomass and quality, were negatively affected by age. Results permitted to assess the evolution of different features of lucerne for a mountain environment and to hypothesize the appropriate management for this resource, that could contemplate also the evolution towards the reconstitution of the reference habitat for the studied area

Evolution of production and forage quality in sown meadows of a mountain area inside Parmesan cheese consortium

Received: January 5th, 2021 ; Accepted: April 7th, 2021 ; Published: May 4th, 2021 ; Correspondence: [email protected] meadows, encompassing alfalfa and grass-legume mixtures, are the forage crops on which is based Parmesan cheese production system in the mountain area of the Apennines (central Italy). These grassland types experience, during their development, deep changes in terms of production potentiality, botanical composition and forage quality, thus these meadows have to be periodically renewed to guarantee adequate productive and qualitative performances. To have an accurate assessment of this evolution along time, a survey was performed in different mountain farms inside the Parmesan cheese consortium, analysing alfalfa meadows and grass-legumes mixtures of different ages. Grasslands were monitored during 2019, performing three samplings during growing season. Aboveground biomass production, botanical composition and crude protein content were collected during the survey. Results permitted to evaluate the level of production decrease along years, the evolution of analysed parameters among cutting dates and the dependence of productive and qualitative features on botanical composition and presence of sown species in the swards. Results were useful to hypothesize the composition of future mixtures, to improve management issues and to delineate the possible duration of sown meadows for the area with respect to different purposes in terms of desired productive or qualitative objectives