416 research outputs found

    Attosecond Streaking in the Water Window: A New Regime of Attosecond Pulse Characterization

    Full text link
    We report on the first streaking measurement of water-window attosecond pulses generated via high harmonic generation, driven by sub-2-cycle, CEP-stable, 1850 nm laser pulses. Both the central photon energy and the energy bandwidth far exceed what has been demonstrated thus far, warranting the investigation of the attosecond streaking technique for the soft X-ray regime and the limits of the FROGCRAB retrieval algorithm under such conditions. We also discuss the problem of attochirp compensation and issues regarding much lower photo-ionization cross sections compared with the XUV in addition to the fact that several shells of target gases are accessed simultaneously. Based on our investigation, we caution that the vastly different conditions in the soft X-ray regime warrant a diligent examination of the fidelity of the measurement and the retrieval procedure.Comment: 14 Pages, 12 figure

    Meissner to vortex phase transition in a two-leg ladder in artificial gauge field

    Get PDF
    International audienceWe consider a two-leg boson ladder in artificial gauge field with hard-core intraleg and negligible interleg interactions. Using numerical simulations based on the Density Matrix Renormalization Group (DMRG) algorithm, combined with a bosonization approach, we study its commensurate-incommensurate transition to a vortex phase at a critical flux. We discuss the finite-size scaling behavior of the longitudinal current near the transition. For weak interchain bo-son hopping, the finite size scaling is in agreement with the predictions from bosonization

    Smoking Cessation on Periodontal and Peri-Implant Health Status: A Systematic Review

    Get PDF
    Since smoking is considered among the main risk factors for the onset and progression of periodontitis and peri-implantitis, the present systematic review aimed to evaluate the effect of smoking cessation on clinical, radiographic, and gingival crevicular periodontal parameters around natural teeth and dental implants in ex-smokers compared to current and non-smokers. The study protocol was developed based on the PRISMA guidelines, the research question was formulated according to the PICO model, and the literature search was conducted through PubMed/MEDLINE, Cochrane library, and BioMed Central databases. From the 916 title/abstracts initially identified, seven articles were included in the present systematic review and assessed for quality through the ROBINS-I tool. Reported findings on clinical and crevicular periodontal parameters around natural teeth were contrasting when comparing ex-smokers to current and non-smokers; thus, individualized recommendations for previous smoker periodontal patients are currently lacking. No data on radiographic parameters were retrieved. Similarly, data on periodontal parameters around dental implants were not available, highlighting the need for focused investigations assessing the role of both smoking habit and cessation on peri-implant health status and responsiveness to treatment

    Levelized Cost of Heat for Linear Fresnel Concentrated Solar Systems

    Get PDF
    In this paper, a deep investigation upon levelized cost of heat (LCOH) produced by small-scale solar linear concentrating Fresnel collectors (CSLFC) is proposed. Solar industrial process heat applications have temperature requirements from about 60 °C to 260 °C. CSLFCs can effectively integrate conventional fossil fuel thermal systems. The study is addressed to assess technology cost projection needed to achieve competitive LCOH. So, on the basis of a framework specifically developed for these economic assessments, the best investment scenarios, in terms of industrial application, geographical location and technical design solutions, where to effectively apply the technology of CSLFC, are highlighted. The analysis has been focused on specific cost of several existing CSLFCs associated with declared performances at different operating temperatures. Two main classes of CSLFC with different total efficiency (optical and thermal) corresponding to various design solutions and specific cost were selected. The expected performances in the whole application temperature range have been evaluated through Glayx Tech proprietary simulation code, including optical and thermal unsteady analysis. A huge database coming from full CSLFC simulation varying latitude, yearly DNI, operating fluid, outlet temperature, thermal storage options, has been collected. CLSFC design and performance requirements are the key-choice to achieve competitive LCOH: the use of high efficiency – high cost components is not always rewarding in terms of final LCOH and must be attentively decided basing on site, irradiation, heat quality and LCOH target. In this perspective, CLSFCs are the most promising for industrial small scale heat applications since they show the greatest potential to reduce manufacturing costs

    Reproductive disorders induced by Chlamydophila spp. infections in an italian mediterranean buffalo (bubalus bubalis) herd

    Get PDF
    The Italian Mediterranean Buffalo (Bubalus bubalis) has low fecundity and high incidence of abortion. Several studies have associated reproductive failure of water buffalo with viral infections but there is limited information on the role of chlamydial infections. To investigate the presence and the role of Chlamydiaceae in water buffalo a retrospective study was performed in a farm where, in the arch of 11 months, the pregnant heifers suffered an abortion rate of 36.8% in the 3rd and 5th month of pregnancy. Antibodies to Chlamydiaceae were detected in 57% of the aborted cows, while the rate of positivity was 0% in overtly healthy cows used as control. By a PCR assay 3 of 14 vaginal swabs from aborted animals tested positive for Chlamydophila agents and, additionally, 3 out of 7 aborted foetuses tested positive for Chlamydophila spp., with two being co-infections by Cp. abortus and Cp. pecorum and one being characterised as Cp. abortus. The presence of anti-Chlamydiaceae antibodies in 57% of the aborted animals and the detection of Chlamydophila agents in foetal organs and in vaginal swabs is consistent with the history of abortions (P<0.002) observed in the herd and may suggest a pathogenic role by Chlamydophila spp. in water buffalo

    Decisional procrastination in academic settings: The role of metacognitions and learning strategies

    Get PDF
    Nowadays, university students suffer from a broad range of problems, such as educational underachievement or the inability to control themselves, that lead to procrastination as a consequence. The present research aimed at analyzing the determinants of decisional procrastination among undergraduate students and at assessing a path model in which self regulated learning strategies mediated the relationship between metacognitive beliefs about procrastination and decisional procrastination. 273 students from Southern Italy filled out a questionnaire composed by: the socio-demographic section, the Metacognitive Beliefs About Procrastination Questionnaire, the procrastination subscale of the Melbourne Decision Making Questionnaire, and the Anxiety, the Time Management, and the Information Processing subscales of the Learning and Study Strategies Inventory. Results showed that the relationship between negative and positive metacognitive beliefs about procrastination and decisional procrastination was mediated only by time management and anxiety. Such findings underlined the crucial role played by learning strategies in predicting the tendency to delay decisional situations and in mediating the relationship between metacognitive beliefs about procrastination and decisional procrastination

    Estimation of buffalo cheese yield by using the chemical-physical parameters of the milk

    Get PDF
    The aim of this study was to estimate cheese yield by using the chemical- physical parameters of the milk. Analysis were performed on 325 milk samples with 80-219 days in milk interval. Furthermore, buffaloes which showed a ratio between theoretical cheese yield (calculated by Altiero formula) and real cheese yield at 28 hours higher (Group A) or lower (Group B) than 0.983, were compared taking into account 5 hypothetical analytical potentialities of laboratories: 1) Fat percentage; 2) Protein and fat percentages; 3) Protein and fat percentages, pH and SH; 4) Protein and fat percentages, pH, SH, urea, protein percentage corrected per urea, lactose, solids-not-fat (SNF) and SCC; 5) Protein and fat percentages, pH, SH, urea, protein percentage corrected per urea, lactose, SNF, SCC, TAMF, milk DM percentage, ash percentage and casein percentage. Correlation and regression analyses with stepwise method were performed for curd quantity in relation to the physic-chemical ad microbiological milk composition by using SPSS 15.0. As expected, R2 value was such high as the number of variables included in the calculation. A higher R2 value was observed in those samples characterized by a ThCY/28CY ratio < 0.983. ThCY calculated according to Altiero et al (1989), underestimated 28CY of +1.8 g/litre in all samples, whereas a difference between –2.2 (Laboratory 2) and +1.0 (Laboratory 3) g/litre was registered if the actual formula is utilized. According to Altiero formula, 28CY was overestimated of 9.6 g/litre in Group A, whereas it was underestimated of 1.8 g/litre in Group B. According to our study, the estimation of 28CY showed a difference between –9.3 (Laboratory 2) and 9 (Laboratory 1) g/litre in Group A and – 3.5 (Laboratory 1) e 0.0 (Laboratory 5) g/litre

    (13C)-Methacetin breath test provides evidence of subclinical liver dysfunction linked to fat storage but not lifestyle

    Get PDF
    Background &amp; Aims: Non-alcoholic fatty liver disease (NAFLD) is characterised by the presence of hepatic steatosis in the absence of other causes of secondary hepatic fat accumulation, and is usually associated with visceral, metabolically active obesity. However, the subclinical effects of body and liver fat accumulation on liver function are still unclear. Methods: We used orally administered (13C)-methacetin and breath test to quantify the efficiency of hepatic extraction from portal blood flow and liver microsomal function in 81 participants, in relation to presence/absence of ultrasonographic NAFLD, extent of body fat accumulation, insulin resistance, dietary models, and lifestyle. Results: NAFLD was present in 23% of participants with normal weight, and prevalence increased with body fat and insulin resistance. Fat accumulation, NAFLD, and insulin resistance were associated with decreased hepatic extraction efficiency, and liver microsomal function was impaired in moderate-to-severe NAFLD. Caloric intake, dietary models, and lifestyles had a minor role in promoting functional changes. Conclusions: The interplay between body fat accumulation, insulin resistance, and NAFLD is linked with altered hepatic extraction efficiency from blood flow and deranged microsomal function. Non-invasive diagnosis of subclinical alterations of liver function is relevant for primary and secondary prevention measures. Furthermore, the occurrence of NAFLD in lean individuals and the evidence that caloric intake, dietary models, and lifestyle played a minor role require further studies exploring the role of environmental factors in the natural history of these diseases. Lay summary: Obesity is progressively increasing worldwide and is paralleled by fat accumulation in the liver (non-alcoholic fatty liver disease [NAFLD]), the most common chronic liver disease worldwide. NAFLD can alter liver structure and function, with a variety of consequences ranging from asymptomatic and subclinical alterations to cirrhosis and cancer. (13C)-Methacetin breath test, a non-invasive diagnostic tool, can reveal early subclinical alterations of liver dynamic function in individuals with obesity and in patients with NAFLD

    Relationship of body condition score and blood urea and ammonia to pregnancy in Italian Mediterranean buffaloes

    Get PDF
    The relationship of body condition score ( BCS) and blood urea and ammonia to pregnancy outcome was examined in Italian Mediterranean Buffalo cows mated by AI. The study was conducted on 150 buffaloes at 145 +/- 83 days in milk that were fed a diet comprising 14.8% crude protein, 0.9 milk forage units . kg(-1) dry matter and a non- structural carbohydrate/ crude protein ratio of 2.14. The stage of the oestrous cycle was synchronised by the Ovsynch- TAI programme and blood urea and ammonia levels were assessed on the day of AI. Energy corrected milk ( ECM) production and BCS were recorded bi- weekly. The pregnancy risk was 46.7% and was slightly lower in buffaloes with BCS 7.5. There were no significant differences in ECM, urea and ammonia between pregnant and non- pregnant buffaloes. However, pregnancy outcome was higher ( P = 0.02) in buffaloes with blood urea < 6.83 mmol . L-1. The likelihood of pregnancy for buffaloes with low urea blood level was 2.6 greater than for high urea level and exposure to a high urea level lowered the probability of pregnancy by about 0.25. The findings indicate that buffaloes are similar to cattle and increased blood levels of urea are associated with reduced fertility when animals are mated by AI
    • …
    corecore