Finite-temperature properties of the Hubbard chain with bond-charge interaction

We investigate the one-dimensional Hubbard model with an additional bond-charge interaction, recently considered in the description of compounds that exhibit strong 1D features above the temperature of ordered phases. The partition function of the model is exactly calculated for a value of the bond-charge coupling; the behavior of the specific heat and spin susceptibility as a function of temperature is derived at arbitrary filling, and particularly discussed across the occurring metal-insulator transition. The results show that the bond-charge terms weaken the spin excitations of the system.Comment: 5 pages, 3 eps figure

“If It Is Written by Allah, There Is Nothing That Can Stop It”: Saudi women’s breast cancer narratives

The purpose of this study was to identify cultural models of breast cancer held by Saudi women and to explore how these may influence early detection and treatment-seeking behaviors. Data were collected via semi-structured interviews with breast cancer survivors (n=20) from two Western cities in Saudi Arabia. Respondents were recruited through social networking, using purposive, snowball sampling. Illness narratives elicited during interviews were transcribed, coded and then analyzed using a modified grounded theory approach. Results suggest that fatalism, perceived threats to traditional role fulfillment, and a preference for traditional therapies commonly mark the breast cancer experiences of Saudi women, influencing their early detection and treatment-seeking behaviors. A more nuanced understanding of emic viewpoints could help to improve public health messaging and intervention strategies in Saudi Arabia

Detection of Tiny Mechanical Motion by Means of the Ratchet Effect

We propose a position detection scheme for a nanoelectromechanical resonator based on the ratchet effect. This scheme has an advantage of being a dc measurement. We consider a three-junction SQUID where a part of the superconducting loop can perform mechanical motion. The response of the ratchet to a dc current is sensitive to the position of the resonator and the effect can be further enhanced by biasing the SQUID with an ac current. We discuss the feasibility of the proposed scheme in existing experimental setups.Comment: 8 pages, 9 figure

Band and filling controlled transitions in exactly solved electronic models

We describe a general method to study the ground state phase diagram of electronic models on chains whose extended Hubbard hamiltonian is formed by a generalized permutator plus a band-controlling term. The method, based on the appropriate interpretation of Sutherland's species, yields under described conditions a reduction of the effective Hilbert space. In particular, we derive the phase diagrams of two new models; the first one exhibits a band-controlled insulator-superconductor transition at half-filling for the unusually high value $U_c=6 t$; the second one is characterized by a filling-controlled metal-insulator transition between two finite regions of the diagram.Comment: 5 pages, REVTEX, 2 eps figure

Electron tunneling into a quantum wire in the Fabry-Perot regime

We study a gated quantum wire contacted to source and drain electrodes in the Fabry-Perot regime. The wire is also coupled to a third terminal (tip), and we allow for an asymmetry of the tip tunneling amplitudes of right and left moving electrons. We analyze configurations where the tip acts as an electron injector or as a voltage-probe, and show that the transport properties of this three-terminal set-up exhibit very rich physical behavior. For a non-interacting wire we find that a tip in the voltage-probe configuration affects the source-drain transport in different ways, namely by suppressing the conductance, by modulating the Fabry-Perot oscillations, and by reducing their visibility. The combined effect of electron electron interaction and finite length of the wire, accounted for by the inhomogeneous Luttinger liquid model, leads to significantly modified predictions as compared to models based on infinite wires. We show that when the tip injects electrons asymmetrically the charge fractionalization induced by interaction cannot be inferred from the asymmetry of the currents flowing in source and drain. Nevertheless interaction effects are visible as oscillations in the non-linear tip-source and tip-drain conductances. Important differences with respect to a two-terminal set-up emerge, suggesting new strategies for the experimental investigation of Luttinger liquid behavior.Comment: 27 pages, 10 figure

“If It Is Written by Allah, There Is Nothing That Can Stop It”: Saudi women’s breast cancer narratives

The purpose of this study was to identify cultural models of breast cancer held by Saudi women and to explore how these may influence early detection and treatment-seeking behaviors. Data were collected via semi-structured interviews with breast cancer survivors (n=20) from two Western cities in Saudi Arabia. Respondents were recruited through social networking, using purposive, snowball sampling. Illness narratives elicited during interviews were transcribed, coded and then analyzed using a modified grounded theory approach. Results suggest that fatalism, perceived threats to traditional role fulfillment, and a preference for traditional therapies commonly mark the breast cancer experiences of Saudi women, influencing their early detection and treatment-seeking behaviors. A more nuanced understanding of emic viewpoints could help to improve public health messaging and intervention strategies in Saudi Arabia

OP0086 GENDER INFLUENCE ON CLINICAL MANIFESTATIONS, DEPRESSIVE SYMPTOMS AND BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) SERUM LEVELS IN PATIENTS AFFECTED BY FIBROMYALGIA

Background:Fibromyalgia (FM) is a common rheumatic disease characterized by chronic widespread pain, sleep and mood disorders. A higher prevalence of FM in women compared with men is well known, although the specific differences in clinical manifestations related to gender are still poorly defined. Brain-Derived Neurotrophic Factor (BDNF) is an endogenous growth factor that gained attention for its potential as biomarker of several diseases, including FM and depression.Objectives:The aims of this study were to investigate gender-related difference among males and females affected by FM in clinical manifestations, depressive features and BDNF serum level, evaluating also the diagnostic potential of the latter.Methods:We consecutively enrolled adult patients affected by FM (ACR 2016) referring to our out-patient clinic. Each subject underwent clinical and answered to questionnaires for the severity of FM symptoms (Revised Fibromyalgia Impact Questionnaire, R-FIQ) and depressive symptoms (Beck Depression Inventory-II, BDI-II). We collected blood samples from a subgroup of patients of both sexes, matched for age, for BDNF serum level dosage through ELISA. BDNF levels were assessed also in a control group, matched for sex and age.Results:The cohort was composed by 201 FM patients (172 F, 29 M), mean age 49.13. Females showed higher values of R-FIQ total score (p=0,0005) as well the specific items of the R-FIQ for pain (p=0,013), fatigue (p=0,014), memory problems (p=0,007), tenderness to touch (p<0,0001), balance problems (p<0,0001) and sensitivity to environmental stimuli (p=0,012) when compared with males (fig. 1). There was no difference in BDI-II between males and females, but notably male patients reported a significantly higher frequency of coexisting depressive disorder (p=0,038) (fig. 2). Serum BDNF levels were evaluated in 40 FM patients and 40 healthy controls (HC) (F:M 1:1). BDNF levels were significantly lower in FM patients compared with HC (p<0,0001). Among FM patients, BDNF levels were lower in males compared with females (p<0,0001) (fig.3). BDNF did not correlate with any clinical and clinimetric parameter. BDNF showed a good diagnostic performance (AUC=0,89, CI95%=0,82-0,9630, p<0,0001) (fig. 4). At a cut-off value <6,47 ng/dl, BDNF showed a specificity of 75% and a sensibility of 92,31%,(CI 95%=79,68-97.35) for FM identification (LR=3,692).Conclusion:FM clinical manifestations are strongly dependant from gender. While females present a more severe disease and a higher burden of symptoms, mood disorders tend to be a major characteristic of males with FM. Reduced BDNF serum levels have been reported as typical of depressive disorders. Our findings of lower BDNF levels in male FM patients compared to females support this hypothesis. BDNF have potential as biomarker of the disease and should be validated in larger cohorts.References:[1]Sarzi-Puttini et al. Nature Reviews 2020[2]Colucci-D'Amato et al. Int J Molecular Sciences 2020[3]Nugraha et al. Rheumatol Int 2012[4]Schmitt et al. Ann Med 2016[5]Melchior et al. Neuroscience 2016[6]Stefani et al. Neuroscience Letters 2012Disclosure of Interests:None declare

Role of the equilibrium size of Kadanoff blocks in the loop-expansion technique

A method developed by the present authors in a previous paper [Phys. Rev. E 57, 2594 (1998)] leads to the introduction of the equilibrium size of the Kadanoff blocks as a useful tool to approach the critical properties of the φ4 model. The present paper aims to elucidate the role of the equilibrium size of the Kadanoff blocks in the loop-expansion technique currently used in the field-theoretic renormalization. While the standard results are readily obtained, aspects emerge that help clarify the true nature of the smallness parameter in the loop-expansion technique

Exact thermodynamics of an Extended Hubbard Model of single and paired carriers in competition

By exploiting the technique of Sutherland's species, introduced in \cite{DOMO-RC}, we derive the exact spectrum and partition function of a 1D extended Hubbard model. The model describes a competition between dynamics of single carriers and short-radius pairs, as a function of on-site Coulomb repulsion ($U$) and filling ($\rho$). We provide the temperature dependence of chemical potential, compressibility, local magnetic moment, and specific heat. In particular the latter turns out to exhibit two peaks, both related to `charge' degrees of freedom. Their origin and behavior are analyzed in terms of kinetic and potential energy, both across the metal-insulator transition point and in the strong coupling regime.Comment: 14 pages, 15 eps figure

A Social-Ecological Perspective on Vulnerable Youth: Toward an Understanding of Sexual Development Among Urban African American Adolescents

The authors employ a social-ecological framework to aid our understanding of the complex array of factors in the immediate and broader environment that influence adolescent sexual development. Further, sexual development is viewed as normative and critical to positive growth. The authors provide an overview of the Two-Cities Study, a multi-stage qualitative investigation that aims to contribute to an understanding of sexual development and to illuminate gender differences in sexuality. The current studies focus on urban African American youth living in low-income neighborhoods, offering new data on sexual development among these youth