Constraining the Higgs self couplings at e+e−e^+e^- colliders

We study the sensitivity to the shape of the Higgs potential of single, double, and triple Higgs production at future $e^+e^-$ colliders. Physics beyond the Standard Model is parameterised through the inclusion of higher-dimensional operators $(\Phi^\dagger \Phi- v^2/2)^n/\Lambda^{(2n-4)}$ with $n=3,4$, which allows a consistent treatment of independent deviations of the cubic and quartic self couplings beyond the tree level. We calculate the effects induced by a modified potential up to one loop in single and double Higgs production and at the tree level in triple Higgs production, for both $Z$ boson associated and $W$ boson fusion production mechanisms. We consider two different scenarios. First, the dimension six operator provides the dominant contribution (as expected, for instance, in a linear effective-field-theory(EFT)); we find in this case that the corresponding Wilson coefficient can be determined at $\mathcal{O}(10\%)$ accuracy by just combining accurate measurements of single Higgs cross sections at $\sqrt{\hat s}=$240-250 GeV and double Higgs production in $W$ boson fusion at higher energies. Second, both operators of dimension six and eight can give effects of similar order, i.e., independent quartic self coupling deviations are present. Constraints on Wilson coefficients can be best tested by combining measurements from single, double and triple Higgs production. Given that the sensitivity of single Higgs production to the dimension eight operator is presently unknown, we consider double and triple Higgs production and show that combining their information colliders at higher energies will provide first coarse constraints on the corresponding Wilson coefficient.Comment: minor changes, version accepted for publication in JHE

Associated production of a top-quark pair with vector bosons at NLO in QCD: impact on ttˉHt \bar{t} H searches at the LHC

We study the production of a top-quark pair in association with one and two vector bosons, $t \bar t V$ and $t \bar t VV$ with $V=\gamma, Z, W^\pm$, at the LHC. We provide predictions at next-to-leading order in QCD for total cross sections and top-quark charge asymmetries as well as for differential distributions. A thorough discussion of the residual theoretical uncertainties related to missing higher orders and to parton distribution functions is presented. As an application, we calculate the total cross sections for this class of processes (together with $t \bar t H$ and $t \bar t t \bar t$ production) at hadron colliders for energies up to 100 TeV. In addition, by matching the NLO calculation to a parton shower, we determine the contribution of $t \bar t V$ and $t \bar t VV$ to final state signatures (two-photon and two-same-sign-, three- and four-lepton) relevant for $t \bar t H$ analyses at the Run II of the LHC.Comment: 44 pages, 23 figures. Version published on JHEP, typos in Table 5 have been correcte

Probing the Higgs self coupling via single Higgs production at the LHC

We propose a method to determine the trilinear Higgs self coupling that is alternative to the direct measurement of Higgs pair production total cross sections and differential distributions. The method relies on the effects that electroweak loops featuring an anomalous trilinear coupling would imprint on single Higgs production at the LHC. We first calculate these contributions to all the phenomenologically relevant Higgs production ($gg{\rm F}$, VBF, $WH$, $ZH$, $t\bar tH$) and decay ($\gamma \gamma$, $WW^{*}/ZZ^{*}\to 4f$, $b\bar b$, $\tau \tau$) modes at the LHC and then estimate the sensitivity to the trilinear coupling via a one-parameter fit to the single Higgs measurements at the LHC 8 TeV. We find that the bounds on the self coupling are already competitive with those from Higgs pair production and will be further improved in the current and next LHC runs.Comment: 34 pages, 13 figures, 5 tables; V2: New appendix A added on the comparison with the Effective Field Theory approach; V3: Journal versio

The hidden burden of food waste: The double energy waste in Italy

The energy intensity of modern food systems represents a major issue in a scenario of decreasing oil resources and increasing population. Beside the use of renewable energy, an increased efficiency in food systems could contribute to reduce fossil fuels dependence. In this sense, food losses and waste (FLW) have crucial consequences on the energy balance. Based on the concept of "embodied energy", food wastage can be framed as a double waste of energy, both in terms of non-consumed food energy and the inputs used for production. Secondary data regarding direct and indirect energy inputs and FLW have been collected for the Italian food chain to estimate the embodied energy of food waste. Since in 2011 the production and distribution of food implied the use of 822 PJ and 18 Mt of food was discarded, 67 PJ of food energy and 100 PJ of embodied energy were wasted. These figures are equivalent to 12.2% of the total nutritional energy output and to 1.3% of the final energy use in Italy, respectively. The concept of double energy waste sheds new light on the intertwined relationship between energy and food security, suggesting that appropriate food waste reduction policies could result in a higher food production level and relevant energy savings

Conformational studies on Arabidopsis sulfurtransferase AtStr1 with spectroscopic methods

Sulfurtransferases/rhodaneses (Str) are enzymes widely distributed in archaea, prokaryota and eukaryota, and catalyze the transfer of sulfur from a donor molecule to a thiophilic acceptor substrate. In this reaction, Str cycles between the sulfur-free and the sulfur-substituted form. Two-domain Str consist of two globular domains of nearly identical size and conformation connected by a short linker sequence, which is elongated in plant two-domain Str proteins compared to Str in other organisms. The two-domain Arabidopsis thaliana Str1 protein (At1g 79230) was expressed in Escherichia coli as a mature protein, as a variant without the elongated linker sequence, and as AtStr1C332S and AtStr1C339V. The persulfuration state of the purified recombinant proteins was investigated in the presence and absence of sulfur donors by fluorescence spectroscopy. The secondary structure was analyzed by circular dichroism (CD) in the far-UV range, while overall changes in tertiary structure were determined by CD in the near-UV range. Finally, protein stability was analyzed by tryptic digestion. The elongated linker sequence is essential for correct conformation and stability, and thereby affects the catalytic activity of AtStr1. Replacement of the catalytic cysteine residue C332 leads to higher rigidity of the molecule, whereas replacement of C339 does not lead to any conformational changes, providing evidence of the direct involvement of C339 in catalysis.DFG/PA/764/1-

Involvement of the Azotobacter vinelandii Rhodanese-Like Protein RhdA in the Glutathione Regeneration Pathway

The phenotypic features of the Azotobacter vinelandii RhdA mutant MV474 (in which the rhdA gene was deleted) indicated that defects in antioxidant systems in this organism were related to the expression of the tandem-domain rhodanese RhdA. In this work, further insights on the effects of the oxidative imbalance generated by the absence of RhdA (e.g. increased levels of lipid hydroperoxides) are provided. Starting from the evidence that glutathione was depleted in MV474, and using both in silico and in vitro approaches, here we studied the interaction of wild-type RhdA and Cys(230) Ala site-directed RhdA mutant with glutathione species. We found that RhdA was able to bind in vitro reduced glutathione (GSH) and that RhdA-Cys(230) residue was mandatory for the complex formation. RhdA catalyzed glutathione-disulfide formation in the presence of a system generating the glutathione thiyl radical (GS(.), an oxidized form of GSH), thereby facilitating GSH regeneration. This reaction was negligible when the Cys230 Ala RhdA mutant was used. The efficiency of RhdA as catalyst in GS(.)-scavenging activity is discussed on the basis of the measured parameters of both interaction with glutathione species and kinetic studies.Vigoni project/0815171Deutscher Akademischer Austausch DienstUniversita` degli Studi di Milano/Fondo interno ricerca scientifica e tecnologic

Intitulados: una mirada desde la comunicación visual

Cuando observamos documentos cuyos encabezados presentan lo que en archivística se conoce como intitulados, difícilmente podemos escapar al análisis de su forma, su composición general, o de los múltiples elementos que los constituyen, como la tipografía, los íconos y los diferentes recursos gráficos. Más allá de la faz estética o decorativa, que por supuesto poseen -y por cierto es plausible de otro tipo de análisis-, estos mensajes presentan una intención manifiesta de comunicación, una propuesta superadora a la función primaria del documento, un plus o valor agregado sobre piezas que tienen funciones específicas, tales como la comercial o administrativa. Así, de esta forma, materiales diversos de papelería comercial, adquieren una nueva dimensión vinculada a la entidad emisora. Desarrollaremos una mirada sobre estos complejos sistemas de signos desde la perspectiva del esquema básico de comunicación propuesto en la Teoría de la Información del lingüista Roman Jakobson: el emisor, los factores propios del mensaje, y el receptor. El propósito es realizar una lectura que nos permita entender de qué forma se generaron estas composiciones, y cómo llegaron -y llegan aún hoy por supuesto- a percibirse.Facultad de Bellas Arte

Accurate pHEMT nonlinear modeling in the presence of low-frequency dispersive effects

Low-frequency (LF) dispersive phenomena due to device self-heating and/or the presence of "traps" (i.e., surface state densities and bulk spurious energy levels) must be taken into account in the large-signal dynamic modeling of III-V field-effect transistors when accurate performance predictions are pursued, since these effects cause important deviations between direct current (dc) and dynamic drain current characteristics. In this paper, a new model for the accurate characterization of these phenomena above their cutoff frequencies is presented, which is able to fully exploit, in the identification phase, large-signal current-voltage (I-V) measurements carried out under quasi-sinusoidal regime using a recently proposed setup. Detailed experimental results for model validation under LF small- and large-signal operating conditions are provided. Furthermore, the I-V model proposed has been embedded into a microwave large-signal pseudomorphic high electron-mobility transistor (pHEMT) model in order to point out the strong influence of LF modeling on the degree of accuracy achievable under millimeter-wave nonlinear operation. Large-signal experimental validation at microwave frequencies is provided for the model proposed, by showing the excellent intermodulation distortion (IMD) predictions obtained with different loads despite the very low power level of IMD products involved. Details on the millimeter-wave IMD measurement setup are also provided. Finally, IMD measurements and simulations on a Ka-band highly linear power amplifier, designed by Ericsson using the Triquint GaAs 0.25-/spl mu/m pHEMT process, are shown for further model validation

Occurrence of two Norovirus outbreaks in the same cafeteria in one week

In October 2017, two outbreaks of gastroenteritis (GE) occurred among patrons of a cafeteria in Italy in one week. Virological and bacteria investigations on stool samples, environment and food were conducted to identify the infectious agents and the possible source of infection. Forty-five cases occurred in the two outbreaks, including 13 laboratory-confirmed cases of norovirus GI. Nine staff members were interviewed, six were confirmed positive for NoV GI and 3 experienced GE symptoms. Bacteria faecal indicators and other bacteria pathogens were not detected in either environmental swab samples or food. A low level of NoV GII was detected in two environmental swab samples. The same GI.6 strain was identified in cases related to both outbreaks, suggesting a common source of infection. Since the two outbreaks occurred in one week, the NoV contamination could have persisted in the cafeteria. Furthermore, virological investigation revealed confirmed cases among food handlers who had worked at the cafeteria between and during the two outbreaks. Several studies highlighted the importance of excluding symptomatic food handlers to prevent contamination of foods and environment

Global diversity in the TAS2R38 bitter taste receptor: Revisiting a classic evolutionary PROPosal

The ability to taste phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP) is a polymorphic trait mediated by the TAS2R38 bitter taste receptor gene. It has long been hypothesized that global genetic diversity at this locus evolved under pervasive pressures from balancing natural selection. However, recent high-resolution population genetic studies of TAS2Rs suggest that demographic events have played a critical role in the evolution of these genes. We here utilized the largest TAS2R38 database yet analyzed, consisting of 5,589 individuals from 105 populations, to examine natural selection, haplotype frequencies and linkage disequilibrium to estimate the effects of both selection and demography on contemporary patterns of variation at this locus. We found signs of an ancient balancing selection acting on this gene but no post Out-Of-Africa departures from neutrality, implying that the current observed patterns of variation can be predominantly explained by demographic, rather than selective events. In addition, we found signatures of ancient selective forces acting on different African TAS2R38 haplotypes. Collectively our results provide evidence for a relaxation of recent selective forces acting on this gene and a revised hypothesis for the origins of the present-day worldwide distribution of TAS2R38 haplotypes