7,424 research outputs found

    Upper critical field in superconductors near ferromagnetic quantum critical points; UCoGe

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    We study the strong-coupling superconductivity near ferromagnetic quantum critical points, mainly focusing on the upper critical fields Hc2H_{c2}. Based on our simple model calculations, we discuss experimentally observed unusual behaviors of Hc2H_{c2} in a recently discovered ferromagnetic superconductor UCoGe. Especially, the large anisotropy between Hc2aH_{c2}\parallel a-axis and Hc2cH_{c2}\parallel c-axis, and the strong-coupling behaviors in Hc2aH_{c2}^{\parallel a} are investigated. We also examine effects of non-analytic corrections in the spin susceptibility on the superconductivity, which can arise from effective long range interactions due to particle-hole excitations.Comment: Proceedings of ICHE2010, Toky

    Scaling of the superfluid density in superfluid films

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    We study scaling of the superfluid density with respect to the film thickness by simulating the xyx-y model on films of size L×L×HL \times L \times H (L>>HL >> H) using the cluster Monte Carlo. While periodic boundary conditions where used in the planar (LL) directions, Dirichlet boundary conditions where used along the film thickness. We find that our results can be scaled on a universal curve by introducing an effective thickness. In the limit of large HH our scaling relations reduce to the conventional scaling forms. Using the same idea we find scaling in the experimental results using the same value of ν=0.6705\nu = 0.6705.Comment: 4 pages, one postscript file replaced by one Latex file and 5 postscript figure

    Accuracy and reproducibility of contrast-enhanced mammography in the assessment of response to neoadjuvant chemotherapy in breast cancer patients with calcifications in the tumor bed

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    This study aimed to evaluate contrast-enhanced mammography (CEM) accuracy and reproducibility in the detection and measurement of residual tumor after neoadjuvant chemotherapy (NAC) in breast cancer (BC) patients with calcifications, using surgical specimen pathology as the reference. Pre-and post-NAC CEM images of 36 consecutive BC patients receiving NAC in 2012–2020, with calcifications in the tumor bed at diagnosis, were retrospectively reviewed by two radiologists; described were absence/presence and size of residual disease based on contrast enhancement (CE) only and CE plus calcifications. Twenty-eight patients (77.8%) had invasive and 5 (13.9%) in situ-only residual disease at surgical specimen pathology. Considering CE plus calcifications instead of CE only, CEM sensitivity for invasive residual tumor increased from 85.7% (95% CI = 67.3–96%) to 96.4% (95% CI = 81.7–99.9% ) and specificity decreased from 5/8 (62.5%; 95% CI = 24.5–91.5%) to 1/8 (14.3%; 95% CI = 0.4–57.9%). For in situ-only residual disease, false negatives decreased from 3 to 0 and false positives increased from 1 to 2. CEM pathology concordance in residual disease measurement increased (R squared from 0.38 to 0.45); inter-reader concordance decreased (R squared from 0.79 to 0.66). Considering CE plus calcifications to evaluate NAC response in BC patients increases sensitivity in detection and accuracy in measurement of residual disease but increases false positives

    Scaling of the specific heat in superfluid films

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    We study the specific heat of the xyx-y model on lattices L×L×HL \times L \times H with LHL \gg H (i.e. on lattices representing a film geometry) using the Cluster Monte--Carlo method. In the HH--direction we apply Dirichlet boundary conditions so that the order parameter in the top and bottom layers is zero. We find that our results for the specific heat of various thickness size HH collapse on the same universal scaling function. The extracted scaling function of the specific heat is in good agreement with the experimentally determined universal scaling function using no free parameters.Comment: 4 pages, uuencoded compressed PostScrip

    Scaling of thermal conductivity of helium confined in pores

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    We have studied the thermal conductivity of confined superfluids on a bar-like geometry. We use the planar magnet lattice model on a lattice H×H×LH\times H\times L with LHL \gg H. We have applied open boundary conditions on the bar sides (the confined directions of length HH) and periodic along the long direction. We have adopted a hybrid Monte Carlo algorithm to efficiently deal with the critical slowing down and in order to solve the dynamical equations of motion we use a discretization technique which introduces errors only O((δt)6)O((\delta t)^6) in the time step δt\delta t. Our results demonstrate the validity of scaling using known values of the critical exponents and we obtained the scaling function of the thermal resistivity. We find that our results for the thermal resistivity scaling function are in very good agreement with the available experimental results for pores using the tempComment: 5 two-column pages, 3 figures, Revtex

    The challenges of clinical trials in fragile X syndrome

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    RATIONALE: Advances in understanding the underlying mechanisms of conditions such as fragile X syndrome (FXS) and autism spectrum disorders have revealed heterogeneous populations. Recent trials of novel FXS therapies have highlighted several challenges including subpopulations with possibly differential therapeutic responses, the lack of specific outcome measures capturing the full range of improvements of patients with FXS, and a lack of biomarkers that can track whether a specific mechanism is responsive to a new drug and whether the response correlates with clinical improvement. OBJECTIVES: We review the phenotypic heterogeneity of FXS and the implications for clinical research in FXS and other neurodevelopmental disorders. RESULTS: Residual levels of fragile X mental retardation protein (FMRP) expression explain in part the heterogeneity in the FXS phenotype; studies indicate a correlation with both cognitive and behavioral deficits. However, this does not fully explain the extent of phenotypic variance observed or the variability of drug response. Post hoc analyses of studies involving the selective mGluR5 antagonist mavoglurant and the GABAB agonist arbaclofen have uncovered significant therapeutic responses following patient stratification according to FMR1 promoter methylation patterns or baseline severity of social withdrawal, respectively. Future studies designed to quantify disease modification will need to develop new strategies to track changes effectively over time and in multiple symptom domains. CONCLUSION: Appropriate selection of patients and outcome measures is central to optimizing future clinical investigations of these complex disorders

    Biomarkers changes after neoadjuvant chemotherapy in breast cancer: A seven-year single institution experience

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    The adoption of neoadjuvant chemotherapy (NACT) for breast cancer (BC) is increasing. The need to repeat the biomarkers on a residual tumor after NACT is still a matter of debate. We verified estrogen receptors (ER), progesterone receptors (PR), Ki67 and human epidermal growth factor receptor 2 (HER2) status changes impact in a retrospective monocentric series of 265 BCs undergoing NACT. All biomarkers changed with an overall tendency toward a reduced expression. Changes in PR and Ki67 were statistically significant (p = 0.001). Ki67 changed in 114/265 (43.0%) cases, PR in 44/265 (16.6%), ER in 31/265 (11.7%) and HER2 in 26/265 (9.8%). Overall, intrinsic subtype changed in 72/265 (27.2%) cases after NACT, and 10/265 (3.8%) cases switched to a different adjuvant therapy accordingly. Luminal subtypes changed most frequently (66/175; 31.7%) but with less impact on therapy (5/175; 2.8%). Only 3 of 58 triple-negative BCs (5.2%) changed their intrinsic subtype, but all of them switched treatment. No correlation was found between intrinsic subtype changes and clinicopathological features. To conclude, biomarkers changes with prognostic implications occurred in all BC intrinsic subtypes, albeit they impacted therapy mostly in HER2 negative and/or hormone receptors negative BCs. Biomarkers retesting after NACT is important to improve both tailored adjuvant therapies and prognostication of patients

    Casimir force in O(n) lattice models with a diffuse interface

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    On the example of the spherical model we study, as a function of the temperature TT, the behavior of the Casimir force in O(n) systems with a diffuse interface and slab geometry d1×L\infty^{d-1}\times L, where 2<d<42<d<4 is the dimensionality of the system. We consider a system with nearest-neighbor anisotropic interaction constants JJ_\parallel parallel to the film and JJ_\perp across it. The model represents the nn\to\infty limit of O(n) models with antiperiodic boundary conditions applied across the finite dimension LL of the film. We observe that the Casimir amplitude ΔCasimir(dJ,J)\Delta_{\rm Casimir}(d|J_\perp,J_\parallel) of the anisotropic dd-dimensional system is related to that one of the isotropic system ΔCasimir(d)\Delta_{\rm Casimir}(d) via ΔCasimir(dJ,J)=(J/J)(d1)/2ΔCasimir(d)\Delta_{\rm Casimir}(d|J_\perp,J_\parallel)=(J_\perp/J_\parallel)^{(d-1)/2} \Delta_{\rm Casimir}(d). For d=3d=3 we find the exact Casimir amplitude ΔCasimir=[Cl2(π/3)/3ζ(3)/(6π)](J/J) \Delta_{\rm Casimir}= [ {\rm Cl}_2 (\pi/3)/3-\zeta (3)/(6 \pi)](J_\perp/J_\parallel), as well as the exact scaling functions of the Casimir force and of the helicity modulus Υ(T,L)\Upsilon(T,L). We obtain that βcΥ(Tc,L)=(2/π2)[Cl2(π/3)/3+7ζ(3)/(30π)](J/J)L1\beta_c\Upsilon(T_c,L)=(2/\pi^{2}) [{\rm Cl}_2(\pi/3)/3+7\zeta(3)/(30\pi)] (J_\perp/J_\parallel)L^{-1}, where TcT_c is the critical temperature of the bulk system. We find that the effect of the helicity is thus strong that the Casimir force is repulsive in the whole temperature region.Comment: 15 pages, 3 figure

    Post-graduate medical education in public health: The case of Italy and a call for action

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    Public health technical expertise is of crucial importance to inform decision makers\u2019 action in the field of health and its broader determinants. Improving education and training of public health professionals for both practice and research is the starting point to strengthen the role of public health so that current health challenges can be efficiently tackled. At the Association of Schools of Public Health in the European Region (ASPHER) Deans\u2019 & Directors\u2019 2017 Annual Retreat, we presented the structure and management of public health training system in Italy, and we reported recent data on Italian public health specialists\u2019 educational experience, employment opportunities and job satisfaction. Public health training in Italy is implemented in the context of the post-graduate medical education residency programme in Hygiene and Preventive Medicine, delivered by 34 University-based Schools of Public Health. We report relatively high employment rates across the county and wide spectrum of career opportunities for young public health specialists. However, job security is low and training expectations only partially met. We call upon other Schools of Public Health to scale up the survey within the broad ASPHER community in a shared and coordinated action of systematically collecting useful data that can inform the development of public health education and training models, their implementation and fruitful interaction with population health, health systems and services
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