Bosonic sector of the two-dimensional Hubbard model studied within a two-pole approximation

The charge and spin dynamics of the two-dimensional Hubbard model in the paramagnetic phase is first studied by means of the two-pole approximation within the framework of the Composite Operator Method. The fully self-consistent scheme requires: no decoupling, the fulfillment of both Pauli principle and hydrodynamics constraints, the simultaneous solution of fermionic and bosonic sectors and a very rich momentum dependence of the response functions. The temperature and momentum dependencies, as well as the dependency on the Coulomb repulsion strength and the filling, of the calculated charge and spin susceptibilities and correlation functions are in very good agreement with the numerical calculations present in the literature

Electron-radiation interaction in a Penning trap: beyond the dipole approximation

We investigate the physics of a single trapped electron interacting with a radiation field without the dipole approximation. This gives new physical insights in the so-called geonium theory.Comment: 12 pages, RevTeX, 6 figures, Approved for publication in Phys. Rev.

A Study of the Antiferromagnetic Phase in the Hubbard Model by means of the Composite Operator Method

We have investigated the antiferromagnetic phase of the 2D, the 3D and the extended Hubbard models on a bipartite cubic lattice by means of the Composite Operator Method within a two-pole approximation. This approach yields a fully self-consistent treatment of the antiferromagnetic state that respects the symmetry properties of both the model and the algebra. The complete phase diagram, as regards the antiferromagnetic and the paramagnetic phases, has been drawn. We firstly reported, within a pole approximation, three kinds of transitions at half-filling: Mott-Hubbard, Mott-Heisenberg and Heisenberg. We have also found a metal-insulator transition, driven by doping, within the antiferromagnetic phase. This latter is restricted to a very small region near half filling and has, in contrast to what has been found by similar approaches, a finite critical Coulomb interaction as lower bound at half filling. Finally, it is worth noting that our antiferromagnetic gap has two independent components: one due to the antiferromagnetic correlations and another coming from the Mott-Hubbard mechanism.Comment: 20 pages, 37 figures, RevTeX, submitted to Phys. Rev.

Modelling Post-tensioned Precast Concrete Segmental Girder Bridges with Keyed Joints – Preliminary Results

Precast concrete segmental bridges (PCSBs) have been the most common design technology used in the last decades. It is widely recognized that segmental bridges have better durability, lower life-cycle costs and higher quality for maintenance than other types of bridges. PCSBs with externally prestressed tendons have become very popular in construction because of economical and safety reasons, fast and practical construction, and outstanding serviceability. Moreover, external tendons technique is widely used because it allows to inspect the cables and to replace them or to reinforce the tendons in case of damage while such kinds of actions are difficult to be taken in case of internal prestressing. Therefore, box section is the most common solution due to its aesthetic appeal and elegance that reduces the environmental impact as well due to the convenient maintenance for the tendons. Besides, the hollow concrete box segment can be used for service/electrical cable ducts for bridges. However, there is lack of reliable computational model for analysing behaviour of post-tensioned PCSBs. This research investigates the behaviour of PCSBs with dry keyed joints and external tendons up to failure with the use of finite element method which is validated by comparing experimental results. Deflection, joint opening, tendon slip, stresses of the tendons and the concrete are obtained from numerical analysis with recommendation on further development towards a more accurate numerical model for PCSBs made

Continuous quantum nondemolition feedback and unconditional atomic spin squeezing

We discuss the theory and experimental considerations of a quantum feedback scheme for producing deterministically reproducible spin squeezing. Continuous nondemolition atom number measurement from monitoring a probe field conditionally squeezes the sample. Simultaneous feedback of the measurement results controls the quantum state such that the squeezing becomes unconditional. We find that for very strong cavity coupling and a limited number of atoms, the theoretical squeezing approaches the Heisenberg limit. Strong squeezing will still be produced at weaker coupling and even in free space (thus presenting a simple experimental test for quantum feedback). The measurement and feedback can be stopped at any time, thereby freezing the sample with a desired amount of squeezing.Comment: 17 pages, 5 figures, submitted to JP

Koagulacija krvi i lipidi u serumu (Studija stanovništva)

Two population groups differing in dietary habits and physical activity were examined on blood lipids and blood coagulability. The results showed a higher lipid concentration and shorter clotting time in the physically less active group, having a higher fat and caloric intake.Dvije populacione grupe, koje se razlikuju po svojoj prehrani, a osobito po povećanoj potrošnji masnoća i smanjenom fizičkom aktivitetu, ispitivane su s obzirom na nivo krvnih lipida i na koagulabilitet krvi. Rezultati pokazuju, da prehrana, osobito povećana potrošnja animalnih masnoća, te smanjena psihička aktivnost utječu na povećanje nivoa krvnih lipida i bržeg koagulabiliteta krvi mjerenog kao vrijeme zgrušavanja i protrombinsko vrijeme. Ti rezultati potvrđuju već ranija zapažanja autora o povećanom koagulabilitetu krvi u populacionim grupama, koje se istovremeno razlikuju i u koncentraciji krvnih lipida i u učestalosti koronarnih bolesti

MicroRNA-551b expression profile in low and high-grade cervical intraepithelial neoplasia

OBJECTIVE: To evaluate the expression of microRNA (miR)-551b in patients with low and high grade cervical intraepithelial neoplasia (CIN) and to find an association with high-risk Human Papillomavirus (HR-HPV) infection-related prognostic biomarkers. PATIENTS AND METHODS: The expression level of miR-551b was determined in 50 paraffin-embedded cervical specimens (10 normal squamous epithelium, 18 condylomas, 8 CIN1, and 14 CIN2-3) using quantitative Real-time polymerase chain reaction (qRT-PCR). χ2-test compared miR-551b expression in different diagnosis groups. An Ordered Logistic Regression and a Probit correlation were made to correlate miR-551b expression levels with the cervical tissue histological findings. The immunohistochemical distribution of p16 and Ki-67 according to histopathological findings was also assessed. RESULTS: The distribution of the miR-551b expression profile was significantly lower in CIN1-3 samples compared to other histological diagnosis groups (condyloma and negative). The expression levels were inversely correlated to the cervical pathological grade, from negative to CIN2-3. A 1% increase in miR-551b expression level produced an increase of 19% to the probability of a minor histological grade diagnosis in a range from negative to CIN2-3 and an increase of 13% to the probability of a negative histological grade diagnosis. Among the cases with miR-551b expression < 0.02 (considered as cut-off value) a significant statistical correlation was found between p16 and Ki-67 expression and the diagnosis of CIN2-3. CONCLUSIONS: O ur d ata s howed a s ignificant inverse correlation between miR-551b expression and the histological grading of the lesions, suggesting a tumor suppressive function in the different stages of cervical dysplasia

What's on your plate? Collecting multimodal data to understand commensal behavior

Eating is a fundamental part of human life and is, more than anything, a social activity. A new field, known as Computational Commensality has been created to computationally address various social aspects of food and eating. This paper illustrates a study on remote dining we conducted online in May 2021. To better understand this phenomenon, known as Digital Commensality, we recorded 11 pairs of friends sharing a meal online through a videoconferencing app. In the videos, participants consume a plate of pasta while chatting with a friend or a family member. After the remote dinner, participants were asked to fill in the Digital Commensality questionnaire, a validated questionnaire assessing the effects of remote commensal experiences, and provide their opinions on the shortcomings of currently available technologies. Besides presenting the study, the paper introduces the first Digital Commensality Data-set, containing videos, facial landmarks, quantitative and qualitative responses. After surveying multimodal data-sets and corpora that we could exploit to understand commensal behavior, we comment on the feasibility of using remote meals as a source to build data-sets to investigate commensal behavior. Finally, we explore possible future research directions emerging from our results

precipitation change in southern italy linked to global scale oscillation indexes

Abstract. This study investigates precipitation variability in five regions of Southern Italy (Campania, Apulia, Basilicata, Calabria and Sicily) using a homogeneous database of about 70 rain gauges with more than 50 years of observation. First, a statistical analysis was performed through the Mann-Kendall non-parametric test in order to determine rainfall the trend on both yearly and seasonal scales. Then, the relationship between the rainfall and some teleconnection pattern indexes was investigated using Spearman's test. The results show remarkable statistically significant negative trends for annual and winter aggregations in most part of the series. Moreover, a strong correlation has emerged between the teleconnection patterns and precipitation in Southern Italy, particularly in winter and on the Tyrrhenian side of the study area

Trait emotional intelligence and eating problems in adults: associations with alexithymia and substance use

Background: Eating Disorders (EDs) often co-occur with substance use contributing to increasing concern about the individual's health; both the conditions share several core features such as the tendency to use maladaptive emotion regulation strategies. The present study investigated associations between trait emotional intelligence (Trait EI), alexithymia and EDs, namely dieting, bulimia and oral control, in a nonclinical sample of adults. Moreover, the relationships with substance use frequencies were also examined with the aim of exploring the links between personality emotional competence traits (trait EI and alexithymia) and different addictive risk behaviours (EDs and substance use) in adulthood.Methods: Data were collected from a convenience sample composed of 394 (312 women; between ages 18 and 65; mean age = 32.34; SD = 11.97) participants, through online administration of questionnaires assessing trait emotional intelligence (TEIQue-SF), eating problems (EAT-26), alexithymia (TAS-20) and frequency of substance use (in the last year).Results: The group that exceeds the cut-off for EDs (n = 58; 14.7 %) has significantly lower trait EI scores (in all dimensions) and higher alexithymia scores than the other group. Some differences between the two groups were found on frequencies of nicotine and diuretics use. Age and all trait EI factors were negatively associated with eating disorders and alexithymia. Weak inverse correlations have emerged between EI and frequencies of substance use (namely cocaine, amphetamines, alcohol and tobacco). Female gender, well-being and self-control factors of EI emerged as significant predictors of EDs in adulthood.Conclusions: Our results suggest the importance of targeting emotion dysregulation for EDs and substance use behaviours. Interventions aimed at promoting healthy lifestyles could benefit from trait EI enhancement efforts. Practitioners and health educators need to recognize the potential efficacy of including trait EI within gender specific interventions planned to address ED symptoms and addictive behaviours in general