Height fluctuations in non-integrable classical dimers

We rigorously establish the asymptotic equivalence between the height function of interacting dimers on the square lattice and the massless Gaussian free field. Our theorem explains the microscopic origin of the sine-Gordon field theory description away from the free fermion point, which has previously been elusive. We use a novel technique, based on the combination of discrete holomorphicity with exact, constructive, renormalization group methods, which has the potential of being applicable to a variety of other non-integrable models at or close to criticality.Comment: 4 pages, 2 figure

Height fluctuations in interacting dimers

We consider a non-integrable model for interacting dimers on the two-dimensional square lattice. Configurations are perfect matchings of $\mathbb Z^2$, i.e. subsets of edges such that each vertex is covered exactly once ("close-packing" condition). Dimer configurations are in bijection with discrete height functions, defined on faces $\boldsymbol{\xi}$ of $\mathbb Z^2$. The non-interacting model is "integrable" and solvable via Kasteleyn theory; it is known that all the moments of the height difference $h_{\boldsymbol{\xi}}-h_{\boldsymbol{\eta}}$ converge to those of the massless Gaussian Free Field (GFF), asymptotically as $|{\boldsymbol{\xi}}-{\boldsymbol{\eta}}|\to \infty$. We prove that the same holds for small non-zero interactions, as was conjectured in the theoretical physics literature. Remarkably, dimer-dimer correlation functions are instead not universal and decay with a critical exponent that depends on the interaction strength. Our proof is based on an exact representation of the model in terms of lattice interacting fermions, which are studied by constructive field theory methods. In the fermionic language, the height difference $h_{\boldsymbol{\xi}}-h_{\boldsymbol{\eta}}$ takes the form of a non-local operator, consisting of a sum of monomials along an {\it arbitrary} path connecting $\boldsymbol{\xi}$ and $\boldsymbol{\eta}$. As in the non-interacting case, this path-independence plays a crucial role in the proof.Comment: 89 pages, 13 figures. v4: few typos corrected. Final version accepted for publication on Annales de l'Institut Henri Poincar\'

Weakly non-planar dimers

We study a model of fully-packed dimer configurations (or perfect matchings) on a bipartite periodic graph that is two-dimensional but not planar. The graph is obtained from $\mathbb Z^2$ via the addition of an extensive number of extra edges that break planarity (but not bipartiteness). We prove that, if the weight $\lambda$ of the non-planar edges is small enough, a suitably defined height function scales on large distances to the Gaussian Free Field with a $\lambda$-dependent amplitude, that coincides with the anomalous exponent of dimer-dimer correlations. Because of non-planarity, Kasteleyn's theory does not apply: the model is not integrable. Rather, we map the model to a system of interacting lattice fermions in the Luttinger universality class, which we then analyze via fermionic Renormalization Group methods.Comment: 44 pages, 9 figures. Final version accepted for publication on Probability and Mathematical Physic

Heterostyly in Goniolimon italicum (Plumbaginaceae), endemic to Abruzzo (central Apennines, Italy)

Goniolimon italicum is an endemic species to central Apennines (Italy). Here we provide the first report of heterostyly in this species. Two morphological types were identified: an S-morph with stamen filaments longer than gynoecia, stigmas with a papillate surface and finely reticulated pollen grains with very small spinules (Type B); and an L-morph with stamen filaments shorter than gynoecia, stigmas with a cob pattern and coarsely reticulated pollen grains with small spinules (Type A). Two new locations of G. italicum were found and are here reported

ÁREA TEMÁTICA – GESTÃO DO BEM ESTAR ESTUDANTIL

Com a expansão do ensino superior no Brasil e o aparecimento de um mercado competitivo exacerbado, o fenômeno da evasão discente dentro das instituições universitárias tem alcançado alto nível de preocupação entre os gestores, afetando profundamente seu desempenho e sobrevivência. A ascensão do marketing educacional nas instituições traz a atuação relacional como alternativa de combate deste fenômeno, visando um relacionamento de longo prazo entre organização e seus estudantes. O estudo apresenta as bases teóricas do elemento lealdade, destaque dentro do âmbito empresarial moderno em termos de manutenção do relacionamento com seus clientes, aplicando-o ao ambiente educacional superior. Os antecedentes da lealdade do estudante com a instituição de ensino superior são apresentados e definidos, levando à implicações gerenciais que devem ser postas em práticas nas universidades e faculdades que desejam aumentar seus índices de retenção

A new polystyrene-based ionomer/MWCNT nanocomposite for wearable skin temperature sensors

The present work outlines the fabrication and testing of a novel skin temperature sensor based on exfoliated and undamaged multi-walled carbon nanotubes (MWCNTs) dispersed in a poly(vinylbenzyl chloride) derivative with triethylamine (PVBC_Et3N). The dispersions were prepared by sonicating MWCNT/ PVBC_Et3N mixtures in dimethylformamide for 5 min and the quantification of the MWCNTs dispersed was evaluated by UV–vis spectroscopy investigations and thermogravimetric analyses. The investigations demonstrated the realization of MWCNT/PVBC_Et3N sensors with a resistance sensitivity to temperature close to 0.004 K1, an absolute value that is comparable to the highest values found in metals. The temperature dependence of the resistance was also found very reproducible in the range 20–40 C, thus suggesting the possibility of using the MWCNT/PVBC_Et3N system for the fabrication of small wearable temperature sensors for the monitoring of chronic wounds

Immigrants and cancer in Italy: a literature review

Immigration is a growing flow in Italy. Also specific health needs could be imported. We focused on cancer. A systematic search for literature in PubMed was performed on 10th March 2016, limited to articles published between 1st March 1996 and 1st March 2016. Papers were reviewed focusing on: specific risks, prevention and care. Cancer incidence is generally lower for immigrants than for natives, also for the health immigrant effect. However, cancers with an infective etiology may have, among some groups of immigrants, a great relevance. Primary or secondary cancer prevention could be greatly improved among immigrants. Moreover, another specific aspect of immigration is at seeking cancer care for children. Specific preventive strategies should be customized for immigrants to get higher compliance, e.g. for those at high risk for cervical cancers. Moreover, the capability of the Italian health system to cope more comprehensively with sick immigrated children and their families should be improved

Acoustic variability and automatic recognition of children’s speech

International audienc

Metastable phase in the quantum Hall ferromagnet

Time-dependent capacitance measurements reveal an unstable phase of electrons in gallium arsenide quantum well that occurs when two Landau levels with opposite spin are brought close to degeneracy by applying a gate voltage. This phase emerges below a critical temperature and displays a peculiar non-equilibrium dynamical evolution. The relaxation dynamics is found to follow a stretched exponential behavior and correlates with hysteresis loops observed by sweeping the magnetic field. These experiments indicate that metastable randomly-distributed magnetic domains are involved in the relaxation process in a way that is equivalently tunable by a change in gate voltage or temperature.Comment: 7 pages, including 4 figures Changes made to introduction Added figure Submitted to SS