1,303 research outputs found

    Superfluid-Insulator and Roughening Transitions in Domain Walls

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    We have performed quantum Monte Carlo simulations to investigate the superfluid behavior of one- and two-dimensional interfaces separating checkerboard solid domains. The system is described by the hard-core Bose-Hubbard Hamiltonian with nearest-neighbor interaction. In accordance with Ref.1, we find that (i) the interface remains superfluid in a wide range of interaction strength before it undergoes a superfluid-insulator transition; (ii) in one dimension, the transition is of the Kosterlitz-Thouless type and is accompanied by the roughening transition, driven by proliferation of charge 1/2 quasiparticles; (iii) in two dimensions, the transition belongs to the 3D U(1) universality class and the interface remains smooth. Similar phenomena are expected for domain walls in quantum antiferromagnets.Comment: 6 pages, 7 figures; references added, typo corrected in fig

    Lipid content and fatty acid methyl ester profile by Chromochloris zofingiensis under chemical and metabolic stress

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    This work encompasses the effect of chemical and metabolic stress on lipid content and fatty acid methyl ester (FAME) profile by Chromochloris zofingiensis. To this aim, a control medium amended with specific concentrations of sodium chloride (15 g L-1, 30 g L-1, and 60 g L-1) and of ethanolamine (ETA) and triethylamine (TEA) (0.050 g L-1, 0.100 g L-1, and 0.150 g L-1) has been used for the cultivation of this strain. A better lipid content than the control was obtained under salt stress compared to chemical stress induced by ETA and TEA, while the effect on lipid productivity was negligible. Thirty grams per liter of NaCl allowed to obtain the highest value of the total lipid content (30.33% DW) compared to the control (20% DW). FAME profile revealed a 97.50-98.99% composition in C16-C18 with no statistically meaningful differences among the three concentrations of salt and chemicals tested. The most represented fatty acids were C18:1 oleic (> 45%wt), C16:0 palmitic (> 34%wt), and C18:2 linoleic (> 21%wt) obtained under 60 and 30 mg L-1 of NaCl and 0.150 g L-1 of ETA, respectively. When using 0.150 g L-1 of ETA, unsaturated fatty acids reached the highest portion (67.53%wt) than the control (62.26%wt). A quantitative and qualitative analysis of all FAMEs has been carried out to improve biodiesel properties. Chemical and physical properties of algal lipid-derived biodiesel showed a compliance with ASTM standards for unmixed biodiesel and the main European regulations (EN 14214 and EN 590) for the quality of biodiesel resulted fulfilled. Therefore, a profitable biodiesel can be obtained when cultivating C. zofingiensis under osmotic stress

    Multiworm algorithm quantum Monte Carlo

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    We review the path-integral quantum Monte Carlo method and discuss its implementation by multiworm algorithms. We analyze in details the features of the algorithms, and focus our attention on the computation of the NN-body density matrix to study N-body correlations. Finally, we demonstrate the validity of the algorithms on a system of dipolar bosons trapped in a stack of NN one-dimensional layers in the case of zero and finite inter-layer hopping.Comment: 20 pages, 10 figure

    Efficacy of methylergometrine during the early puerperium: a randomized double-blind placebo-controlled clinical trial

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    OBJECTIVE: To determine if oral methylergometrine administration during the first 10 d following spontaneous vaginal delivery has any beneficial effect on the increase of hemoglobin levels. METHODS: This was a parallel group double-blind placebo-controlled clinical trial conducted at single center university hospital in Italy. Participants were puerperal women, who delivered singleton gestation with spontaneous vaginal delivery at term. Participants were randomized into a 1:1 ratio to receive either 0.125 mg methylergometrine per os twice a day or placebo for 10 d. Hemoglobin levels were recorded on the day of delivery and after 10 d. The primary outcome was the variation in hemoglobin levels between the first and the 10th day of treatment. RESULTS: From December 2012 to October 2015, 220 agreed to take part in the study, underwent randomization, and were enrolled and followed-up. Of the randomized women, 110 (50%) were randomized to the methylergometrine group and 110 (50%) to the placebo group. No women were excluded after randomization or lost to follow-up (100%). We found no significant difference in the median variation of hemoglobin levels between the intervention and the placebo group Conclusions: The use of 10 d oral methylergometrine in puerperal women was not associated with any benefit in the variation of hemoglobin levels from delivery to 10 d after delivery. Key Message Methylergometrine in puerperal women was not associated with any benefit

    Risk of Drop-Out from Follow-Up Evaluations for Celiac Disease: Is It Similar for All Patients?

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    Background: Celiac disease (CD) follow-up is a relatively underevaluated topic. However, correct adherence to follow-up procedures is central to the early recognition of complicated CD and other conditions typically associated with CD. Establishing whether patients at increased risk of complications follow clinicians’ recommendations has multiple repercussions. Methods: We retrospectively analyzed the records of patients consecutively diagnosed with CD in our outpatient clinic between January 2004 and October 2017 to investigate the factors associated with drop-out from follow-up procedures. Results: Among the 578 patients analyzed, 40 (6.9%) dropped out during the first six months and 272 (50.6%) during the observation period. The median time to drop-out was 7.4 years (95% confidence interval: 6.8–8.0). No factors were associated with early drop-out. Instead, age at diagnosis >40 years (40–59 years, p < 0.001; ≥60 years, p = 0.048) and classical clinical presentation (p = 0.016) were significantly associated with a lower risk of later drop-out. Conclusions: Patients at increased risk of complicated CD are more compliant with follow-up procedures than patients at lower risk, despite being prescribed the same controls. These results indirectly support the hypothesis of tailored follow-up strategies, differentiated according to the risk of complications

    Experience with regorafenib in the treatment of hepatocellular carcinoma

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    Regorafenib is a diphenylurea oral multikinase inhibitor, structurally comparable to sorafenib, which targets a variety of kinases implicated in angiogenic and tumor growth-promoting pathways. Regorafenib was the first agent to positively show significant survival advantage as a second-line therapy in patients with unresectable hepatocellular carcinoma (HCC) who had previously failed first-line treatment with sorafenib. Recent evidence has shown that its antitumor efficacy is due to a comprehensive spectrum of tumor neo-angiogenesis and proliferation inhibition and immunomodulatory effects on the tumor microenvironment, which plays a crucial role in tumor development. This review addresses the rationale and supporting evidence for regorafenib’s efficacy in HCC that led to regorafenib’s approval as a second-line therapy. In addition, we review proof from clinical practice studies that validate the RESORCE trial results. We discuss regorafenib’s potential role in the newly emerging therapeutic strategy based on combination with immune checkpoint blockade and its possible extensibility to patient categories not enrolled in the registrative study

    Do grade II ankle sprains have chronic effects on the functional ability of ballet dancers performing single-leg flat-foot stance? An observational cross-sectional study

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    Ballet dancers have a higher risk than the general population of ankle sprains. Ankle proprioception is of the utmost importance for executing static and dynamic positions typical of ballet dancing. Ankle sprains can create changes in functional ability that may affect ballet performance. The aim of this cross-sectional observational study is to evaluate if non-professional ballet dancers that were previously injured with a grade II ankle sprain carry a long-term stability deficit in ballet specific positions (pass\ue9, arabesque) and in single-leg flat-foot stance, thereby affecting ballet performance. We enrolled 22 amateur female ballet dancers, 11 who previously had a grade II ankle injury and 11 who had no history of ankle injury. Stabilometric data (Center of Pressure Speed and Elipse Area) were assessed with the postural electronic multisensory baropodometer in normal, arabesque, and pass\ue8 positions with both open and closed eyes. Using an unpaired t-test, we compared healthy and pathological feet of the ankle injury group for a standard monopodalic position and two ballet-specific positions. No difference between pathological and healthy feet of non-professional ballet dancers who suffered grade II ankle injury was detected. According to the parameters considered in this study, grade II ankle sprains seem to have a favorable prognosis in the sample that we evaluated

    A Framework for Recommending Multimedia Cultural Visiting Paths

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    In this work, we present a general framework for Cultural Heritage applications able to uniformly manage heterogeneous multimedia data coming from several web repositories and to provide context- Aware recommendation services in order to generate dynamic multimedia visiting paths useful for the users during the exploration of different kinds of cultural sites. A specific application of our system within the cultural heritage domain is proposed together with some experimental results

    Treatment of late-stage Freiburg\u2019s disease using a temporary metal interpositional device

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    There are few reports of the surgical treatment for late stage Freiburg\u2019s disease with flattening of the metatarsal head and osteoarthritis. We describe the results of the surgical treatment of ten consecutive patients with advanced stage Freiburg\u2019s disease (Smillie\u2019s stage V), using a technique that has not been published previously

    Qualitative Analysis of Causal Anisotropic Viscous Fluid Cosmological Models

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    The truncated Israel-Stewart theory of irreversible thermodynamics is used to describe the bulk viscous pressure and the anisotropic stress in a class of spatially homogeneous viscous fluid cosmological models. The governing system of differential equations is written in terms of dimensionless variables and a set of dimensionless equations of state is utilized to complete the system. The resulting dynamical system is then analyzed using standard geometric techniques. It is found that the presence of anisotropic stress plays a dominant role in the evolution of the anisotropic models. In particular, in the case of the Bianchi type I models it is found that anisotropic stress leads to models that violate the weak energy condition and to the creation of a periodic orbit in some instances. The stability of the isotropic singular points is analyzed in the case with zero heat conduction; it is found that there are ranges of parameter values such that there exists an attracting isotropic Friedmann-Robertson-Walker model. In the case of zero anisotropic stress but with non-zero heat conduction the stability of the singular points is found to be the same as in the corresponding case with zero heat conduction; hence the presence of heat conduction does not apparently affect the global dynamics of the model.Comment: 35 pages, REVTeX, 3 Encapsulated PostScript Figure
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