The XYZ chain with Dzyaloshinsky-Moriya interactions: from spin-orbit-coupled lattice bosons to interacting Kitaev chains

Using the density-matrix renormalization-group algorithm (DMRG) and a finite-size scaling analysis, we study the properties of the one-dimensional completely-anisotropic spin-1/2 XYZ model with Dzyaloshinsky-Moriya (DM) interactions. The model shows a rich phase diagram: depending on the value of the coupling constants, the system can display different kinds of ferromagnetic order and Luttinger-liquid behavior. Transitions from ferromagnetic to Luttinger-liquid phases are first order. We thoroughly discuss the transition between different ferromagnetic phases, which, in the absence of DM interactions, belongs to the XX universality class. We provide evidence that the DM exchange term turns out to split this critical line into two separated Ising-like transitions and that in between a disordered phase may appear. Our study sheds light on the general problem of strongly-interacting spin-orbit-coupled bosonic gases trapped in an optical lattice and can be used to characterize the topological properties of superconducting nanowires in the presence of an imposed supercurrent and of interactions.Comment: 18 pages, 8 figure

Spatial and temporal coherence of filtered thermal light.

When a filter is placed in front of a double slit illuminated by a primary source of finite extent, the theory of partial coherence predicts that in general the interference fringes do not acquire unit visibility even as the passband of the filter is made arbitrarily narrow. The effect of reducing the filter bandwidth is that the visibility of the fringes tends to the modulus of the spectral degree of coherence and that more interference fringes become visible. A systematic experimental verification of these theoretical predictions is lacking so far and is provided here from the use of a highly sensitive CCD camera

Experimental Study of the Mechanical Behaviour of Double Twisted Steel Mesh Gabions

AbstractThe study of the mechanical behaviour of gabion elements is a fundamental prerequisite for an improved understanding about the overall mechanical performance of retaining structures realized using this construction technique. The paper discusses the first part of a wide experimental research program. The current article is limited to the description of the modalities to define a comprehensive experimental campaign, which involves both compression and direct shear tests. The testing matrix is designed considering several variables related to the two main components of the basic constructive element, steel cage and filling material respectively. The setup of instruments and the testing procedure are also discussed in the paper

First data on microflora of loggerhead sea turtle (Caretta caretta) nests from the coastlines of Sicily

Caretta caretta is threatened by many dangers in the Mediterranean basin, but most are human-related. The purposes of this research were: (i) to investigate microflora in samples from six loggerhead sea turtle nests located on the Sicilian coast and (ii) to understand microbial diversity associated with nests, with particular attention to bacteria and fungi involved in failed hatchings. During the 2016 and 2018 summers, 456 eggs and seven dead hatchling from six nests were collected. We performed bacteriological and mycological analyses on 88 egg samples and seven dead hatchlings, allowing us to isolate: Fusarium spp. (80.6%), Aeromonas hydrophila (55.6%), Aspergillus spp. (27.2%) and Citrobacter freundii (9%). Two Fusarium species were identified by microscopy and were confirmed by PCR and internal transcribed spacer sequencing. Statistical analyses showed significant differences between nests and the presence/absence of microflora, whereas no significant differences were observed between eggs and nests. This is the first report that catalogues microflora from C. caretta nests/eggs in the Mediterranean Sea and provides key information on potential pathogens that may affect hatching success. Moreover, our results suggest the need for wider investigations over extensive areas to identify other microflora, and to better understand hatching failures and mortality related to microbial contamination in this important turtle species

A relevance index method to infer global properties of biological networks

Many complex systems, both natural and artificial, may be represented by networks of interacting nodes. Nevertheless, it is often difficult to find meaningful correspondences between the dynamics expressed by these systems and the topological description of their networks. In contrast, many of these systems may be well described in terms of coordinated behavior of their dynamically relevant parts. In this paper we use the recently proposed Relevance Index approach, based on information-theoretic measures. Starting from the observation of the dynamical states of any system, the Relevance Index is able to provide information about its organization. Moreover, we show how the application of the proposed approach leads to novel and effective interpretations in the T helper network case study

The detection of anti-Trichinella antibodies in free-ranging Nebrodi Regional Park black pigs from Sicily, Italy, suggests the circulation of Trichinella britovi in the island

Abstract • Zoonotic nematodes of the genus Trichinella are known to occur in countries bordering the Mediterranean Sea. For example, Trichinella spiralis was reported in pigs and humans at the turn of the Second World War in Sicily and Trichinella britovi in pigs, red foxes and dogs from Corsica and Sardinia since 2004. Following the discovery of T. britovi in Corsica and Sardinia, a question arose as to whether this species was also present in Sicily which is located only 3.14 km from continental Italy. To address this query, we investigated the presence of anti-Trichinella antibodies in the serum of Nebrodi black pigs, a breed that is bred in the wild in the Nebrodi Regional Park, a protected area of the island rich in flora and fauna. Blood samples were collected from 112 Nebrodi black pigs from five farms. Sera were tested by ELISA and ELISA positive sera were confirmed by Western blot (Wb) using excretory/secretory antigens. Eighteen (16.1%) serum samples belonging to 17 fattening pigs and 1 boar tested positive by Wb. Positive sera tested by Wb using crude worm extract antigens (CWE), displayed a banding pattern similar to the CWE-Wb pattern of T. spiralis and T. britovi reference pig sera but different to that of T. pseudospiralis reference pig sera. No larvae were detected in muscles of serologically positive pigs by artificial digestion. The presence of anti-Trichinella antibodies in the absence of larvae in the muscles, suggests that the pigs were infected with T. britovi and not T. spiralis whose larvae survive in the muscles for at least two years. These results suggest that T. britovi is circulating in Nebrodi Regional Park in Sicily. ELISA testing may constitute a suitable tool for large-scale screening of Trichinella spp. infection in free-ranging pigs, when ELISA-positive sera are confirmed by Wb. Free-ranging animals can act as sentinels for the presence of zoonotic nematodes of the genus Trichinella in wildlife

Sensory Processing, Gastrointestinal Symptoms and Parental Feeding Practices in The Explanation of Food Selectivity: Clustering Children with and Without Autism

Children with Autism Spectrum Disorders are a group of neurodevelopmental disorders (ASD) and compared to Typically Developing Children (TDC), experience significantly more feeding problems. Food selectivity is a complex phenomenon that involves individual and contextual factors (sensory abnormalities, severity of behavioral problems, gastrointestinal disorders, parenting styles and so on). The clarification of these key factors is the aim of the current study, comparing a group of children with ASD with a group of TDC on different variables such as food selectivity, anthropometric measures, gastrointestinal symptoms, diet, sensory processing and caregiver feeding practices. Moreover, the same variables described above are studied using a classification model for both groups. Results display that parenting style, sensory anomalies and gastrointestinal symptoms were associated with food refusal of children. Moreover, it is possible to observe similar profiles in children with feeding problems in both groups. Autism Spectrum Disorders (ASD) are a group of neurodevelopmental disorders characterized by social communication deficit and a tendency to engage in a pattern of restricted and repetitive behaviors, in which sensory issues are included (American Psychiatric Association [APA], [1]). Children with ASD, compared to Typically Developing Children (TDC), experience significantly more feeding problems [2], with food selectivity being the most frequently reported. Food selectivity could be operationally defined on the basis of the occurrence of the following behaviours: food refusal, limited repertoires of food, high frequency single food intake [3]. Several research studies observed a prevalence between 70% and 80% of food selectivity among children with ASD [4-6], despite parents never having described their children as in appetent [7]. Klein and Nowak (1999) [8] found that 53% of children were reluctant to try new foods. Whiteley, Rodgers, and Shattok (2000) [9] indicated a prevalence of 83% of children with a restricted repertoire of foods eaten. Similarly, Schreck and Williams (2006) [6] found that 57% of children refused food, while 72% accepted limited variety. A more consistent prevalence was found by Lockner, Crowe, and Skipper (2008), [10] who thought that new foods refusal in children with ASD was higher compared to TDC (95% vs. 47%). Furthermore, children with ASD were characterized also by a limited variety of food intake (16% vs. 58%). However, Bandini et al. (2010) [3] found lower rates of refusal in both groups compared to previous studies (41.7% vs. 18.9%). Methodological differences in research studies such as different approach mechanisms may have accounted for conflicting results. Food selectivity in ASD is really important because it is linked to health risks for children, and it may require some medical intervention [11]. In fact, in a recent review by the same authors, BMI and other anthropometric values in children with autism seem to differ from that of TDC, along with nutritional insufficiency [12]. However, in this survey as well as other recent studies [13,14] this difference was not always confirmed, with the literature still seeming incomplete. At the same time several studies tried to identify some of the causes for food selectivity in children with ASD. Some researchers investigated the role of motor coordination disorders and/or gastrointestinal problems. Children with praxis difficulties may lack the necessary motor skills to adequately handle food, leading to negative emotions avoidance [15]. Also, researchers have found contrasting results in Gastrointestinal Disorders (GID). According to a recent survey, a higher frequency of GID may be associated with a more severe food selectivity in children with ASD [16], while for others, the two phenomena seem largely independent in children with autism [17]. Indeed, children with and without autism experiencing frequently bowel problems and/or gastroesophageal reflux could display more feeding-related problems, since they could try to avoid foods associated with adverse circumstances. On the other hand, many children with autism commonly well-defined as picky or choosy eaters do not show gastrointestinal issues. In fact, other authors explained food selectivity in children with ASD as a consequence of repetitive behaviour and restricted interests [18,19]. However, the most accepted etiological hypothesis would seem to postulate a relationship between sensory perception abnormalities and rejection of food [20] both from children with typical and atypical development. As shown by Nadon, Feldman, Dunn, and Gisel (2011) [21], almost 90% of children with ASD show impairment in sensory processing information, including a hypo and or hypersensitivity to environmental stimuli. The differences in sensory processing in children with ASD have been well documented [22]. These abnormalities have been associated with both behavioural and emotional problems [23,24] and the severity of symptoms [25]. Since foods have several properties which can stimulate sense organs, it is possible that children who have sensory perception alteration might refuse them to a greater extent as they are more or less stimulating. From interviews with parents and behavioural observations it has been proven that children with ASD are adverse towards food characteristics such as texture, smell, taste and temperature [10,14,23,26-28], yet other food properties seem to be more important to them such as brand, packaging (patterns/colours), food presentation and even cutlery [4,6,9]. Finally, eating behaviours not only have a biological matrix but are also influenced by social and cultural variables [29], therefore it’s possible that in addition to the individual dimensions, parental feeding practices can also play a significant role in food selectivity. Currently, a research study [13] evaluated the parental feeding style and the food selectivity in children with ASD, indicating strategies as prompting/encouragement as the most used among parents. This direction of research is of particular interest not only scientifically but also in the way of application. If a relationship between parental feeding practices and food selectivity is found, it will be possible to devise intervention programs aimed at promoting functional parenting styles in order to achieve healthy eating behaviors. Hence, the aim of the current study is to compare a group of children with ASD with a group of TDC on different variables such as food selectivity, weight, gastrointestinal disorders, diet, sensory process and caregiver feeding practices. To sum up, we want to explore the following research questions: a) if the group of children with ASD shows more levels of food selectivity than controls; b) if the children with ASD report lower scores of BMI than controls; c) if the clinical group shows more sensory abnormalities than controls; d) if an association between food selectivity, BMI, GID, sensory dimensions and parental feeding styles can be established in both groups of children, e) if it is possible to discover similar profiles of children in both groups