923 research outputs found
Control of the interaction in a Fermi-Bose mixture
We control the interspecies interaction in a two-species atomic quantum
mixture by tuning the magnetic field at a Feshbach resonance. The mixture is
composed by fermionic 40K and bosonic 87Rb. We observe effects of the large
attractive and repulsive interaction energy across the resonance, such as
collapse or a reduced spatial overlap of the mixture, and we accurately locate
the resonance position and width. Understanding and controlling instabilities
in this mixture opens the way to a variety of applications, including formation
of heteronuclear molecular quantum gases.Comment: 5 Page
Endophytic Fungi of Tomato and Their Potential Applications for Crop Improvement
In this work, considerations are made to the effects and methods of introduction and detection of Endophytic Fungi on tomato plants, consolidating in a review the main findings that regard pest and pathogen control, and improvement of plant performance. Moreover, a survey was undertaken of the naturally occurring constitutive endophytes present in this horticultural crop, with the aim to evaluate the potential role in the selection of new beneficial Endophytic Fungi useful for tomato crop improvement
Synthesis by sol-gel technique and Antibacterial activity of bioactive hydrid SiO2 inorganic matrix by different structures of Ferrous citrate (Fe(II)C): comparative study
Abstract.
The aim of this work was to characterize and compare three different structures of Ferrous citrate (Fe(II)C), amorphous, semi-crystalline and crystalline incorporated into a SiO2 inorganic matrix by sol-gel technique. On this system thus obtained, colorimetric assay was carried out to confirm the only presence of Fe2+; Fourier transform infrared spectroscopy (FTIR) confirmed not only the Fe(II)C presence in the silica matrix but also showed us the interactions among different components in the hybrid materials. The bioactivity of the synthesized hybrid materials was evaluated by the formation of a layer of hydroxyapatite on the surface of samples soaked in SBF using FTIR spectroscopy. Finally, the antibacterial properties of the hybrid materials were investigated
An international prospective general population-based study of respiratory work disability
Background: Previous cross-sectional studies have shown that job change due to breathing problems at the workplace (respiratory work disability) is common among adults of working age. That research indicated that occupational exposure to gases, dust and fumes was associated with job change due to breathing problems, although causal inferences have been tempered by the cross-sectional nature of previously available data. There is a need for general population-based prospective studies to assess the incidence of respiratory work disability and to delineate better the roles of potential predictors of respiratory work disability.Methods: A prospective general population cohort study was performed in 25 centres in 11 European countries and one centre in the USA. A longitudinal analysis was undertaken of the European Community Respiratory Health Survey including all participants employed at any point since the baseline survey, 6659 subjects randomly sampled and 779 subjects comprising all subjects reporting physician-diagnosed asthma. The main outcome measure was new-onset respiratory work disability, defined as a reported job change during follow-up attributed to breathing problems. Exposure to dusts (biological or mineral), gases or fumes during follow-up was recorded using a job-exposure matrix. Cox proportional hazard regression modelling was used to analyse such exposure as a predictor of time until job change due to breathing problems.Results: The incidence rate of respiratory work disability was 1.2/1000 person-years of observation in the random sample (95% CI 1.0 to 1.5) and 5.7/1000 person-years in the asthma cohort (95% CI 4.1 to 7.8). In the random population sample, as well as in the asthma cohort, high occupational exposure to biological dust, mineral dust or gases or fumes predicted increased risk of respiratory work disability. In the random sample, sex was not associated with increased risk of work disability while, in the asthma cohort, female sex was associated with an increased disability risk (hazard ratio 2.8, 95% CI 1.3 to 5.9).Conclusions: Respiratory work disability is common overall. It is associated with workplace exposures that could be controlled through preventive measures
Heavy Superheated Droplet Detectors as a Probe of Spin-independent WIMP Dark Matter Existence
At present, application of Superheated Droplet Detectors (SDDs) in WIMP dark
matter searches has been limited to the spin-dependent sector, owing to the
general use of fluorinated refrigerants which have high spin sensitivity. Given
their recent demonstration of a significant constraint capability with
relatively small exposures and the relative economy of the technique, we
consider the potential impact of heavy versions of such devices on the
spin-independent sector. Limits obtainable from a -loaded SDD
are estimated on the basis of the radiopurity levels and backgrounds already
achieved by the SIMPLE and PICASSO experiments. With 34 kgd exposure,
equivalent to the current CDMS, such a device may already probe to below
10 pb in the spin-independent cross section.Comment: 9 pages, 4 figures, accepted Phys. Rev.
Danneggiamento per pitting di acciai bonificati, cementati e nitrurati
La comprensione dei meccanismi di danneggiamento che portano al manifestarsi dell’usura per faticaè di fondamentale importanza per l’ottimizzazione dei materiali e dei trattamenti termici.Il presente lavoro ha previsto l’esecuzione di prove di rotazione disco su disco (rolling disc-on-disc test).Questo metodo si basa sulla rotazione simultanea di una coppia di dischi sagomati in modo da simulareil contatto tra superfici sferiche. Le prove sono state eseguite su tre differenti tipi di acciaio:• UNI EN 42CrMo4 bonificato; • UNI EN 18NiCrMo5 cementato; • UNI EN 42CrMo4 nitruratoLo scopo del presente lavoro è quello di identificare i meccanismi di danneggiamento coinvoltinella fase di innesco del fenomeno di usura per fatica e durante la sua evoluzione.A tal proposito sui campioni ottenuti dalle prove di rotazione disco su disco sono state condotte numerose analisifrattografiche sia ad occhio nudo, che mediante l’utilizzo del microscopio elettronico a scansione (SEM).Sono stati identificati differenti meccanismi di danneggiamento a seconda del tipo di acciaio:• UNI EN 42CrMo4 bonificato: pitting dovuto a cricche originate negli strati superficialifortemente incruditi. • UNI EN 18NiCrMo5 cementato: pitting originato dagli ossidi depositati a bordo granodurante la fase di carburazione. • UNI EN 42CrMo4 nitrurato: pitting dovuto a cricche che siinnescano e propagano all’interno della coltre bianca
Observation of an Efimov spectrum in an atomic system
In 1970 V. Efimov predicted a puzzling quantum-mechanical effect that is
still of great interest today. He found that three particles subjected to a
resonant pairwise interaction can join into an infinite number of loosely bound
states even though each particle pair cannot bind. Interestingly, the
properties of these aggregates, such as the peculiar geometric scaling of their
energy spectrum, are universal, i.e. independent of the microscopic details of
their components. Despite an extensive search in many different physical
systems, including atoms, molecules and nuclei, the characteristic spectrum of
Efimov trimer states still eludes observation. Here we report on the discovery
of two bound trimer states of potassium atoms very close to the Efimov
scenario, which we reveal by studying three-particle collisions in an ultracold
gas. Our observation provides the first evidence of an Efimov spectrum and
allows a direct test of its scaling behaviour, shedding new light onto the
physics of few-body systems.Comment: 10 pages, 3 figures, 1 tabl
The effects of stratosphere-troposphere coupling on the decadal predictability of the climate system.
The coupled ocean-atmosphere CMCC-CMS model is used to investigate the influence of the stratosphere on the decadal predictability. As part of the EU-funded COMBINE Project, a set of decadal prediction experiments are performed for the 1960-2005 period, following the CMIP5 protocol using historical radiative forcing conditions, followed by RCP4.5 scenario settings from 2006 onward. The decadal predictions consist in 3-member ensembles of 10-year simulations starting at 5-year intervals, with the ocean initial states provided by ocean reanalyses differing by assimilation methods and assimilated data. A purpose of this work is to asses the impact of the initialization to reproduce climate variations with respect to an uninitialized climate simulation performed for the same time period of the predictions using identical forcing conditions.
Focus will be also laid on the differences between simulations by high-top configuration (CMCC- CMS), including a well-resolved stratosphere and equivalent simulations using a low top model differing only in vertical extent and vertical resolution, to estimate how the inclusion of a well- represented stratosphere could impact climate predictability on the decadal time scale
Milk Metabolomics Reveals Potential Biomarkers for Early Prediction of Pregnancy in Buffaloes Having Undergone Artificial Insemination.
This study aimed to identify potential biomarkers for early pregnancy diagnosis in buffaloes subjected to artificial insemination (AI). The study was carried out on 10 pregnant and 10 non-pregnant buffaloes that were synchronized by Ovsynch-Timed Artificial Insemination Program and have undergone the first AI. Furthermore, milk samples were individually collected ten days before AI (the start of the synchronization treatment), on the day of AI, day 7 and 18 after AI, and were analyzed by LC–MS. Statistical analysis was carried out by using Mass Profile Professional (Agilent Technologies, Santa Clara, CA, USA). Metabolomic analysis revealed the presence of several metabolites differentially expressed between pregnant and non-pregnant buffaloes. Among these, a total of five metabolites were identified by comparison with an online database and a standard compound as acetylcarnitine (3-Acetoxy-4-(trimethylammonio)butanoate), argininesuccinic acid hydrate, 5’-O-{[3-({4-[(3aminopropyl)amino]butyl}amino)propyl]carbamoyl}-2’deoxyadenosine, N-(1-Hydroxy-2-hexadecanyl)pentadecanamide, and N-[2,3Bis(dodecyloxy)propyl]-L-lysinamide). Interestingly, acetylcarnitine was dominant in milk samples collected from non-pregnant buffaloes. The results obtained from milk metabolic profile and hierarchical clustering analysis revealed significant differences between pregnant and non-pregnant buffaloes, as well as in the metabolite expression. Overall, the findings indicate the potential of milk metabolomics as a powerful tool to identify biomarkers of early pregnancy in buffalo undergoing AI
Multicentre investigation of neutron contamination at cardiac implantable electronic device (CIED) location due to high-energy photon beams using passive detectors and Monte Carlo simulations
Radiotherapy treatments involving LINACs operating at accelerating potentials >10 MV generate (photo)neutrons which deliver dose to patients also outside the target volume. This effect is particularly relevant for patients with cardiac implantable electronic devices (CIEDs), which can be damaged by the therapeutic irradiation. In the last few years, there has been a rising interest in this issue, and it seems that damage to CIEDs is primarily associated with the thermal component of the photoneutron field. In particular, a recent study led by Politecnico di Milano considered CIEDs from various manufacturers and showed that some of these devices can be damaged after an irradiation with a thermal neutron fluence of about 10^9 cm^-2. The present work results from a collaboration among Politecnico di Milano, the University of Pisa, the University of Trieste and three Italian hospitals located in Lucca, Trieste and Varese, respectively, and it is primarily aimed at evaluating the thermal neutron fluence in CIED region for some high-energy treatments delivered at 15 and 18 MV and to determine whether it is comparable to the critical value given above, which has been experimentally determined to be potentially harmful for CIEDs. Thermal neutron fluence was measured through CR-39 detectors and TLDs, which were housed inside a BOMAB-like phantom mimicking the patient’s trunk. The experimental sessions involved two models of LINAC, Varian Clinac DHX (Varese hospital) and Elekta Synergy (Lucca and Trieste hospitals). The experimental results show that the treatments considered in this study can lead to a thermal neutron fluence in the cardiac region comparable to the critical value. Furthermore, detailed Monte Carlo geometries for the facilities involved in this project were developed with the MCNP code (v. 6.2), and they were tested by comparing simulation results to measurements considering some benchmark irradiation plans. Bubble detectors were also employed for fast neutron fluence measurements to be compared to simulation outputs. These computational models stand out as promising tools for the investigations required in this work, and they can be used for further studies also extending their use to analogous facilities hosting the same models of LINACs
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