498 research outputs found

    Crystal Shape-Dependent Magnetic Susceptibility and Curie Law Crossover in the Spin Ices Dy2Ti2O7 and Ho2Ti2O7

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    We present an experimental determination of the isothermal magnetic susceptibility of the spin ice materials Dy2Ti2O7 and Ho2Ti2O7 in the temperature range 1.8-300 K. The use of spherical crystals has allowed the accurate correction for demagnetizing fields and allowed the true bulk isothermal susceptibility X_T(T) to be estimated. This has been compared to a theoretical expression based on a Husimi tree approximation to the spin ice model. Agreement between experiment and theory is excellent at T > 10 K, but systematic deviations occur below that temperature. Our results largely resolve an apparent disagreement between neutron scattering and bulk measurements that has been previously noted. They also show that the use of non-spherical crystals in magnetization studies of spin ice may introduce very significant systematic errors, although we note some interesting - and possibly new - systematics concerning the demagnetizing factor in cuboidal samples. Finally, our results show how experimental susceptibility measurements on spin ices may be used to extract the characteristic energy scale of the system and the corresponding chemical potential for emergent magnetic monopoles.Comment: 11 pages, 3 figures 1 table. Manuscript submitte

    Un bus come spazio pubblico. Multiculturalismo ed etnografia urbana a Milano

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    Il contributo presenta gli esiti di un‘attività didattica e di ricerca sul campo condotta presso il Politecnico di Milano a ridosso di un tema chiave: il ruolo degli spazi pubblici urbani come supporto per la negoziazione delle differenze e nell’ingaggiare diversi individui e popolazioni in situazioni di confronto e coesistenza. Un’esplorazione di tipo etnografico ha messo sotto osservazione un mezzo di trasporto pubblico quale spazio pubblico “compresso”. Il filobus 90/91 a Milano è stato assunto quale terreno di osservazione privilegiato sui rapidi processi di cambiamento sociale e demografico che hanno investito Milano negli ultimi anni entro una prospettiva di ricerca sulla dimensione quotidiana del multiculturalismo.The paper draws on a research and teaching project carried out with an international class of students in Urban Ethnography in the MSC in Urban Planning and Policy at Politecnico di Milano (Italy). A particular focus of the project was on exploring the role played by public spaces in supporting the coexistence of a multitude of strangers in the city through the continuous negotiation of diversity and difference. In the field work, spatial and social dynamics occurring in a particular and ‘compressed’ public space – the 90-91 trolley-bus circle-line in Milan – are explored and discussed as a space of confrontation in a perspective of daily multiculturalism

    Effect of Hypertension on Outcomes of High-Risk Patients After BCG-Treated Bladder Cancer

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    Immunotherapy with Bacillus Calmette Guerin (BCG) is the most efficacious treatment for high-risk bladder cancer (BC) (Ta/T1 or carcinoma in situ) to reduce the risk of recurrence. Our aim was to evaluate whether hypertension and diabetes influence the outcome of patients with noninvasive BC treated with BCG instillations. In order to collect homogeneous data, we considered as "hypertensive" only those patients who had previous diagnosed hypertension and a history of taking medical therapy with antihypertensive drugs (AHT), and as "diabetic" only those prescribed oral antidiabetics or insulin (ADT). We analyzed 343 high-risk BC patients undergoing BCG 1995 2010) with a median follow-up of 116 months (range 48-238). The distribution of various kinds of AHT and antidiabetic drugs was homogeneous, with no significant differences (p > 0.05). In both univariate and multivariate analyses, the only statistically significant parameter propostic for recurrence after BCG treatment was AHT. Recurrence-liee survival curves showed a significant correlation with AHT (p = 0.0168, hazards ratio [HR] 1.45, 95% confidence interval [CI] 1.0692-1.9619); there was no correlation ( p = 0.9040) with ADT (HR 0.9750, 95% CI 0.6457-1.4721). After stratification of AHT and A.DT according to drug(s) prescribed, there were no significant differences in the BC recurrence rate (p > 0.05). In this study with a very long-term follow-up, hypertension alone (evaluated by AHT) revealed the increased risk of BC recurrence after BCG treatment. Several hypotheses have been formulated to support these findings, but further prospective studies are needed to both evaluate the real influence of hypertension and identify a possible prognostic factor to be used in selecting poor-prognosis BC patients as early candidates for surgical treatment

    Septo-optic Dysplasia- Case Report

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    The clinical triad of septo-optic dysplasia (SOD) comprises the absence of the septum pellucidum, congenital optic nerve dysplasia, and multiple endocrine disorders. When any two of these factors are present, the condition is defined as an incomplete form of SOD. The authors report the case of an incomplete form of SOD in a 9-year-old boy with low vision and nystagmus present from birth. The bilateral ophthalmoscopic examination revealed small papillae with double contour images. Magnetic resonance imaging showed hypoplasia of the optic nerve bilaterally, chiasm and absence of the septum pellucidum.674653655De Morsier, G., Études sur les dysraphies cranio-encéphaliques. III. Agénésie du septum pellucidum avec malformation du tractus optique: La dysplasie septo-optique (1956) Schweiz Arch Neurol Psychiatr, 77 (1-2), pp. 267-292. , Texto inglês: [Studies on malformation of cranio-encephalic sutures.III. Agenesis of the septum lucidum with malformation of the optic tractKaplan, S., Grumbach, M.M., Hoyt, W., The syndrome of hypopituitary dwarfism, hypoplasia of optic nerves and malformation of prosencephalon: Report of 6 patients (1970) Pediatr Res, 4, pp. 480-481Lippe, B., Kaplan, S.A., La Franchi, S., Septo-optic dysplasia and maternal age (1979) Lancet, 2 (8133), pp. 92-93Purdy, F., Maternal factors in septo-optic dysplasia (1979) J Pediatr, 95 (4), p. 661Lambert, S.R., Hoyt, C.S., Narahara, M.H., Optic nerve hypoplasia (1987) Surv Ophthalmol, 32 (1), pp. 1-9Davis, G.V., Shock, J.P., Septo-optic dysplasia associated with see-saw nystagmus (1975) Arch Ophthalmol, 93 (2), pp. 137-139Williams, J., Brodsky, M.C., Griebel, M., Glasier, C.M., Caldwell, D., Thomas, P., Septo-optic dysplasia: The clinical insignificance of an absent septum pellucidum (1993) Dev Med Child Neurol, 35 (6), pp. 490-501Willnow, S., Kiess, W., Butenandt, O., Dörr, H.G., Enders, A., Strasser-Vogel, B., Endocrine disorders in septo-optic dysplasia (De Morsier syndrome) - evaluation and follow up of 18 patients (1996) Eur J Pediatr, 155 (3), pp. 179-18

    A comparison of energy and thermal performance of rooftop greenhouses and green roofs in Mediterranean climate: A hygrothermal assessment in WuFi

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    In urban areas, a considerable proportion of energy demand is allocated to buildings. Since rooftops constitute one-fourth of all urban surfaces, an increasing amount of attention is paid to achieving the most efficient shapes and component designs compatible with every climate and urban context, for rooftops of varying sizes. In this study, three types of rooftop technologies, namely insulated, green roof, and rooftop greenhouse, are evaluated for energy and thermal performance using computer simulations. Water surface exposure, absorption, and intrusion are the three important factors in the calculation of hygrothermal models that impact energy consumption and building envelope performance; however, a few studies are specifically focused on providing realistic results in multi-dimensional hygrothermal models and the assessment of the impact of moisture in roofing solutions. This paper aims at evaluating the performance of three different roofing technologies through a two-dimensional hygrothermal simulation in software WUFI. To accomplish this, a precise localized microclimate model of a complex urban context on the scale of a neighborhood was employed to evaluate the cooling and heating loads of the buildings, the impact of the water content in the green roof on the thermal behavior of the roof surface, and the feasibility of designing a building with nearly zero cooling needs. A two-story building in the city center of Bologna, Italy is modelled. Simulation results have shown that during the cooling period, the performance of the designed rooftop greenhouse is the most effective by 50% reduction in cooling loads. Besides, the impact of moisture in green roofs has been detected as a negative factor for thermal and energy performance of the building in the Mediterranean climate. The results ultimately highlighted the capability of passively-designed rooftop greenhouses to create a building with nearly zero cooling needs

    Turning agricultural wastes into biomaterials: Assessing the sustainability of scenarios of circular valorization of corn cob in a life-cycle perspective

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    Circular economy plays a key role in increasing the sustainability of the agricultural sector, given the countless possibilities of transforming crop residues and recycling precious resources. The maize cultivation process produces a significant amount of residual organic materials, commonly left on the field, as a soil conditioner and source of nutrients even if some parts, such as the cob, play a minor role in these actions. The solutions for the valorization of this remnant depend on economic and environmental factors and the evaluation of the environmental performances of the processes in a life-cycle perspective is important to compare the overall sustainability of the valorization alternatives, maximizing their environmental added value. This work reports the results of Life Cycle Analysis, from cradle-to-gate of corn cob valorized as a raw material in two scenarios: corn cob pellet and corn cob abrasive grits to use as blasting or finishing media. A comparative study has been performed with two products available on the market and with the same functions. The results show that cob-based products have lower impact than those currently used. The work provides indication for evaluating the benefits of turning agricultural wastes in natural-based materials and intends to promote circular economy processes in agriculture production

    Epidemiology and In Vitro Activity of Ceftazidime/Avibactam, Meropenem/Vaborbactam and Imipenem/Relebactam against KPC-Producing K. pneumoniae Collected from Bacteremic Patients, 2018 to 2020

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    The management of KPC-producing K. pneumoniae (KPC-Kp) in bloodstream infections (BSIs) represent a serious clinical challenge. In this study, the aim is to assess the incidence of resistance to novel β-lactams-β-lactamase inhibitor combinations (βL-βLICs), such as ceftazidime-avibactam (CAZ-AVI), meropenem-vaborbactam (MER-VAB) and imipenem-relebactam (IMI-REL), in KPC-Kp strains collected during a three-year period from patients with bacteremia. KPC-Kp strains resistant to βL-βLICs were selected for whole-genome sequencing. A total of 133 K. pneumoniae strains were isolated, and KPC-Kp strains were the most represented (87.2%). In 2018, resistance to CAZ-AVI and MER-VAB was 6.5% and 14.5%, respectively. In 2019, KPC-Kp resistance to CAZ-AVI and MER-VAB remained at low levels, with values of 12.9% and 3.2%, respectively. During 2020, CAZ-AVI resistance was detected in 2/23 of KPC-Kp strains (8.7%). IMI-REL was the most active βL-βLIC, inhibiting >98% of the isolates, while CAZ-AVI and MER-VAB inhibited 87-93% and 85-97% of the KPC producers, respectively. Correlations between genotypic traits and resistance to βL-βLICs showed that KPC-Kp strains resistant to CAZ-AVI harbored a mutation within the blaKPC-3 gene, while all KPC-Kp strains resistant to CAZ-AVI, MER-VAB and/or IMI-REL carried the blaKPC-3 gene. Moreover, genetic analysis of porin genes showed that 14/16 of KPC-Kp resistant isolates possessed a truncated OmpK35 and glycine (G) and aspartic acid (D) insertions at positions 134-135 within OmpK36, whereas 2/16 displayed truncated OmpK35 and OmpK36 porins. Novel βL-βLICs are promising agents against KPC-Kp infections; however, the emergence of resistance to these agents highlights the need for continuous surveillance and application of enhanced antimicrobial stewardship

    Behavior and welfare of undocked heavy pigs raised in buildings with different ventilation systems

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    The present study aimed to evaluate animal welfare of pigs from the same farm, raised with two ventilation systems. The study involved 60 pens of fattening pigs, raised in two buildings: one naturally ventilated (NV) and the other mechanically ventilated (MV). Pigs were assessed on three observation days: at 40 kg (T1), 100 kg (T2), and 160 kg (T3) of live weight. Animal-based measures were used such as qualitative behavioral analysis (QBA), behavioral measures (BMs), and lesion and health measures (LHMs). Housing conditions (HCs) measured at each observation day were the number of pigs per pen, space allowance, temperature, light, and CO2. The association study was performed using a general linear model and analysis of variance. Ventilation effect was analyzed by performing computational fluid dynamics. Results showed that overall pigs raised in the MV were in a more positive affective state. Despite that, with hot temperatures, the higher oc-currence of pig soiling indicated heat stress in pigs and consequent welfare impairment. The higher frequency of pigs showing dog sitting behavior at T2 and T3 suggest welfare worsening in the last phases of fattening. The study concludes that ventilation system influences animal behavior and overall animal welfare, especially during the warmer season

    Increased Energy Demand during Adrenergic Receptor Stimulation Contributes to Ca2+ Wave Generation

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    AbstractWhile β-adrenergic receptor (β-AR) stimulation ensures adequate cardiac output during stress, it can also trigger life-threatening cardiac arrhythmias. We have previously shown that proarrhythmic Ca2+ waves during β-AR stimulation temporally coincide with augmentation of reactive oxygen species (ROS) production. In this study, we tested the hypothesis that increased energy demand during β-AR stimulation plays an important role in mitochondrial ROS production and Ca2+-wave generation in rabbit ventricular myocytes. We found that β-AR stimulation with isoproterenol (0.1 ΟM) decreased the mitochondrial redox potential and the ratio of reduced to oxidated glutathione. As a result, β-AR stimulation increased mitochondrial ROS production. These metabolic changes induced by isoproterenol were associated with increased sarcoplasmic reticulum (SR) Ca2+ leak and frequent diastolic Ca2+ waves. Inhibition of cell contraction with the myosin ATPase inhibitor blebbistatin attenuated oxidative stress as well as spontaneous SR Ca2+ release events during β-AR stimulation. Furthermore, we found that oxidative stress induced by β-AR stimulation caused the formation of disulfide bonds between two ryanodine receptor (RyR) subunits, referred to as intersubunit cross-linking. Preventing RyR cross-linking with N-ethylmaleimide decreased the propensity of Ca2+ waves induced by β-AR stimulation. These data suggest that increased energy demand during sustained β-AR stimulation weakens mitochondrial antioxidant defense, causing ROS release into the cytosol. By inducing RyR intersubunit cross-linking, ROS can increase SR Ca2+ leak to the critical level that can trigger proarrhythmic Ca2+ waves

    Visualisations with semantic icons: Assessing engagement with distracting elements

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    As visualisations reach a broad range of audiences, designing visualisations that attract and engage becomes more critical. Prior work suggests that semantic icons entice and immerse the reader; however, little is known about their impact with informational tasks and when the viewer’s attention is divided because of a distracting element. To address this gap, we first explored a variety of semantic icons with various visualisation attributes. The findings of this exploration shaped the design of our primary comparative online user studies, whereparticipants saw a target visualisation with a distracting visualisation on a web page and were asked to extract insights. Their engagement was measured through three dependent variables: (1) visual attention, (2) effort to write insights, and (3) self-reported engagement. In Study 1, we discovered that visualisations with semantic icons were consistently perceived to be more engaging than the plain version. However, we found no differences in visual attention and effort between the two versions. Thus, we ran Study 2 using visualisations with more salient semantic icons to achieve maximum contrast. The results were consistent with our first Study. Furthermore, we found that semantic icons elevated engagement with visualisations depicting less interestingand engaging topics from the participant’s perspective. We extended prior work by demonstrating the semantic value after performing an informational task (extracting insights) and reflecting on the visualisation, besides its value to the first impression. Our findings may be helpful to visualisation designers and storytellers keen on designing engaging visualisations with limited resources. We also contribute reflections on engagement measurements with visualisations and provide future directions
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