Ground state order and spin-lattice coupling in tetrahedral spin systems Cu2Te2O5X2

High-resolution ac susceptibility and thermal conductivity measurement on Cu2Te2O5X2(X=Br,Cl) single crystals are reported. For Br-sample, sample dependence prevents to distinguish between possibilities of magnetically ordered and spin-singlet ground states. In Cl-sample a three-dimensional transition at 18.5 K is accompanied by almost isotropic behavior of susceptibility and almost switching behavior of thermal conductivity. Thermal conductivity studies suggest the presence of a tremendous spin-lattice coupling characterizing Cl- but not Br-sample. Below the transition Cl-sample is in a complex magnetic state involving AF order but also the elements consistent with the presence of a gap in the excitation spectrum.Comment: version accepted for publication in Phys.Rev.B-Rapid Communicatio

Building a Web marketing experience: the Maltese case of Where's Everybody

L’attività di web marketing, concepita fino ad oggi come esclusiva dell’impresa, sta vivendo un’evoluzione in senso sociale e partecipativo che dipende dall’evoluzione stessa del Web. Quello che in particolare si modifica non è lo scopo, che rimane sempre la soddisfazione del cliente e la sua fidelizzazione, ma l’avere a disposizione di utilizzo una “cassetta degli strumenti” più ampia e malleabile. Partendo dalla considerazione di questo fatto, la scelta dell’argomento del presente lavoro di ricerca è avvenuta in seguito a un’esperienza lavorativa di tre mesi presso il Dipartimento di Marketing & Public Relation di Where’s Everybody, una delle maggiori aziende di produzione televisiva a Malta. Questa opportunità mi è stata offerta grazie a una borsa di studio del Progetto Leonardo. Alla luce di questa prospettiva, si è cercato innanzitutto di fornire un’accurata analisi delle variabili del macro-ambiente che rendono Malta un caso particolare in Europa, sia economico, politico che sociale e culturale. In seguito si è definito il micro-ambiente, ovvero il panorama televisivo locale e la concorrenza, con particolare attenzione alla descrizione e al target dei programmi di Where’s Everybody. Il capitolo successivo è dedicato a come il Web 2.0 sta modificando gli assi portanti dell’attività di marketing, e in generale al marketing 2.0. In particolare, saranno delineate le principali caratteristiche del web marketing, non tutte ma soltanto quelle relative al lavoro svolto e all’azienda presa in considerazione. Queste sono: lo spostamento di valore dalla transazione alla relazione; il paradigma di comunicazione many-to-many e i suoi elementi fondanti (comunità virtuale, user-generated content e passaparola); l’empowerment del consumatore e il cambiamento della definizione del marketing mix. Queste considerazioni vengono applicate nella seconda parte del lavoro, in cui vengono analizzati gli strumenti e le applicazioni di web marketing utilizzati dall’azienda maltese, prima, dopo e durante il mio periodo di lavoro. Essi sono analizzati per siti Internet, social networks e servizi streaming e on-demand. In particolare, l’analisi dei punti di forza e di debolezza dell’impiego di questi strumenti serve come spunto per presentare suggerimenti di miglioramento per la strategia complessiva, in accordo con i concetti chiave del Web 2.0, ovvero collaborazione e partecipazione degli utenti. Con ciò si dimostra che Where’s Everybody ha saputo cogliere le opportunità di evoluzione del marketing in un’ottica 2.0, comprovate dai dati forniti dall’Authority delle Comunicazioni e dalle indagini di mercato svolte dalla Media Warehouse di Malta. Lo scopo finale è quindi quello di fornire, in prima istanza, una mappatura generale dello scenario di cambiamento del Web 2.0 e conseguentemente dell’attività di marketing. In seconda istanza, preso il caso pratico di una casa di produzione televisiva non italiana, il presente lavoro si propone di offrire un esempio di azienda capace di sfruttare al meglio le effettive potenzialità dei nuovi strumenti di web marketing, sottolineando le strategie adottate e l’abilità di creare valore aggiunto per i suoi clienti

Ruthenocuprates RuSr2(Eu,Ce)2Cu2O10: Intrinsic magnetic multilayers

We report ac susceptibility data on RuSr_2(Eu,Ce)_2Cu_2O_(10-y) (Ru-1222, Ce content x=0.5 and 1.0), RuSr_2GdCu_2O_8 (Ru-1212) and SrRuO_3. Both Ru-1222 (x=0.5, 1.0) sample types exhibit unexpected magnetic dynamics in low magnetic fields: logarithmic time relaxation, switching behavior, and `inverted' hysteresis loops. Neither Ru-1212 nor SrRuO_3 exhibit such magnetic dynamics. The results are interpreted as evidence of the complex magnetic order in Ru-1222. We propose a specific multilayer model to explain the data, and note that superconductivity in the ruthenocuprate is compatible with both the presence and absence of the magnetic dynamics.Comment: 9 pages, 11 figures, Revtex; submitted to Phys.Rev.

Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV

High prevalence of childhood multi-drug resistant tuberculosis in Johannesburg, South Africa: a cross sectional study

<p>Abstract</p> <p>Background</p> <p>There are limited data on the prevalence of multi-drug resistant tuberculosis (MDR-TB), estimated at 0.6-6.7%, in African children with tuberculosis. We undertook a retrospective analysis of the prevalence of MDR-TB in children with <it>Mycobacterium tuberculosis </it>(MTB) at two hospitals in Johannesburg, South Africa.</p> <p>Methods</p> <p>Culture-confirmed cases of MTB in children under 14 years, attending two academic hospitals in Johannesburg, South Africa during 2008 were identified and hospital records of children diagnosed with drug-resistant TB were reviewed, including clinical and radiological outcomes at 6 and 12 months post-diagnosis. Culture of <it>Mycobacterium tuberculosis </it>complex (MTB) was performed using the automated liquid broth MGIT™ 960 method. Drug susceptibility testing (DST) was performed using the MGIT™ 960 method for both first and second-line anti-TB drugs.</p> <p>Results</p> <p>1317 children were treated for tuberculosis in 2008 between the two hospitals where the study was conducted. Drug susceptibility testing was undertaken in 148 (72.5%) of the 204 children who had culture-confirmed tuberculosis. The prevalence of isoniazid-resistance was 14.2% (n = 21) (95%CI, 9.0-20.9%) and the prevalence of MDR-TB 8.8% (n = 13) (95%CI, 4.8-14.6%). The prevalence of HIV co-infection was 52.1% in children with drug susceptible-TB and 53.9% in children with MDR-TB. Ten (76.9%) of the 13 children with MDR-TB received appropriate treatment and four (30.8%) died at a median of 2.8 months (range 0.1-4.0 months) after the date of tuberculosis investigation.</p> <p>Conclusions</p> <p>There is a high prevalence of drug-resistant tuberculosis in children in Johannesburg in a setting with a high prevalence of HIV co-infection, although no association between HIV infection and MDR-TB was found in this study. Routine HIV and drug-susceptibility testing is warranted to optimize the management of childhood tuberculosis in settings such as ours.</p

Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente