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1.
Phys Rev Lett ; 124(10): 107001, 2020 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-32216412

RESUMEN

We present resistivity and thermal-conductivity measurements of superconducting FeSe in intense magnetic fields up to 35 T applied parallel to the ab plane. At low temperatures, the upper critical field µ_{0}H_{c2}^{ab} shows an anomalous upturn, while thermal conductivity exhibits a discontinuous jump at µ_{0}H^{*}≈24 T well below µ_{0}H_{c2}^{ab}, indicating a first-order phase transition in the superconducting state. This demonstrates the emergence of a distinct field-induced superconducting phase. Moreover, the broad resistive transition at high temperatures abruptly becomes sharp upon entering the high-field phase, indicating a dramatic change of the magnetic-flux properties. We attribute the high-field phase to the Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) state, where the formation of planar nodes gives rise to a segmentation of the flux-line lattice. We point out that strongly orbital-dependent pairing as well as spin-orbit interactions, the multiband nature, and the extremely small Fermi energy are important for the formation of the FFLO state in FeSe.

2.
Phys Rev Lett ; 122(7): 077001, 2019 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-30848633

RESUMEN

FeSe is argued as a superconductor in the Bardeen-Cooper-Schrieffer Bose-Einstein condensation crossover regime where the superconducting gap size and the superconducting transition temperature T_{c} are comparable to the Fermi energy. In this regime, vortex bound states should be well quantized and the preformed pairs above T_{c} may yield a pseudogap in the quasiparticle-excitation spectrum. We performed spectroscopic-imaging scanning tunneling microscopy to search for these features. We found Friedel-like oscillations near the vortex, which manifest the quantized levels, whereas the pseudogap was not detected. These apparently conflicting observations may be related to the multiband nature of FeSe.

3.
Clin Endocrinol (Oxf) ; 88(6): 830-837, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29498081

RESUMEN

OBJECTIVE: Growth hormone (GH) and its main mediator, insulin-like growth factor-I (IGF-I), play a significant role in bone metabolism. The relations between IGF-I and bone mineral density (BMD) or osteoporosis have been assessed in previous studies but whether the associations are sex-specific remains uncertain. Moreover, only a few studies examined bone quality assessed by quantitative ultrasound (QUS). We aimed to investigate these associations in the general population of north-east Germany. DESIGN AND MEASUREMENTS: Data from 1759 men and 1784 women who participated in the baseline examination of the Study of Health in Pomerania (SHIP)-Trend were used. IGF-I and IGF-binding protein-3 (IGFBP-3) concentrations were measured on the IDS-iSYS multidiscipline automated analyser (Immunodiagnostic Systems Limited). QUS measurements were performed at the heel (Achilles InSight, GE Healthcare). Sex-specific linear and multinomial logistic regression models adjusted for potential confounders were calculated. RESULTS: Linear regression analyses revealed significant positive associations between IGF-I and IGF-I/IGFBP-3 ratio, a marker for free IGF-I, with all QUS parameters in men. Among women, we found an inverse association between IGF-I and the QUS-based fracture risk but no association with any other QUS parameter. There was no association between IGFBP-3 and the QUS-based fracture risk. CONCLUSIONS: Our data suggest an important role of IGF-I on bone quality in men. The observed association of IGF-I with the QUS-based stiffness index and QUS-based fracture risk in this study might animate clinicians to refer patients with low IGF-I levels, particularly men, to a further evaluation of risk factors for osteoporosis and a detailed examination of the skeletal system.


Asunto(s)
Proteína 3 de Unión a Factor de Crecimiento Similar a la Insulina/metabolismo , Factor I del Crecimiento Similar a la Insulina/metabolismo , Adulto , Densidad Ósea/fisiología , Femenino , Fracturas Óseas , Hormona del Crecimiento/sangre , Hormona del Crecimiento/metabolismo , Humanos , Proteína 3 de Unión a Factor de Crecimiento Similar a la Insulina/sangre , Modelos Lineales , Modelos Logísticos , Masculino , Persona de Mediana Edad , Osteoporosis/sangre , Osteoporosis/metabolismo , Unión Proteica , Factores de Riesgo
4.
Sci Rep ; 7(1): 16463, 2017 11 28.
Artículo en Inglés | MEDLINE | ID: mdl-29184108

RESUMEN

A new type of proton acceleration stemming from large-scale gradients, low-density targets, irradiated by an intense near-infrared laser is observed. The produced protons are characterized by high-energies (with a broad spectrum), are emitted in a very directional manner, and the process is associated to relaxed laser (no need for high-contrast) and target (no need for ultra-thin or expensive targets) constraints. As such, this process appears quite effective compared to the standard and commonly used Target Normal Sheath Acceleration technique (TNSA), or more exploratory mechanisms like Radiation Pressure Acceleration (RPA). The data are underpinned by 3D numerical simulations which suggest that in these conditions a Low Density Collisionless Shock Acceleration (LDCSA) mechanism is at play, which combines an initial Collisionless Shock Acceleration (CSA) to a boost procured by a TNSA-like sheath field in the downward density ramp of the target, leading to an overall broad spectrum. Experiments performed at a laser intensity of 1020 W/cm2 show that LDCSA can accelerate, from ~1% critical density, mm-scale targets, up to 5 × 109 protons/MeV/sr/J with energies up to 45(±5) MeV in a collimated (~6° half-angle) manner.

5.
Phys Rev Lett ; 117(5): 054801, 2016 Jul 29.
Artículo en Inglés | MEDLINE | ID: mdl-27517774

RESUMEN

We observe a deuteron beam polarization lifetime near 1000 s in the horizontal plane of a magnetic storage ring (COSY). This long spin coherence time is maintained through a combination of beam bunching, electron cooling, sextupole field corrections, and the suppression of collective effects through beam current limits. This record lifetime is required for a storage ring search for an intrinsic electric dipole moment on the deuteron at a statistical sensitivity level approaching 10^{-29} e cm.

8.
J Adolesc Health ; 27(5): 298-301, 2000 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11044700

RESUMEN

High-risk male adolescents were surveyed to collect data to be used to develop strategies to enhance communication with their partners about sexually transmitted diseases (STDs). Participants were concerned about acquiring an STD from their partner, and reported an increased likelihood of communicating about STD-related issues when confidential health care was available.


Asunto(s)
Comunicación , Servicios Preventivos de Salud/estadística & datos numéricos , Parejas Sexuales , Enfermedades de Transmisión Sexual/prevención & control , Adolescente , Humanos , Masculino , Motivación , Sexo Seguro , Sudeste de Estados Unidos
12.
J Adolesc Health ; 18(1): 4-9, 1996 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8750422

RESUMEN

BACKGROUND AND OBJECTIVE: Treatment of sex partners is an essential part of sexually transmitted diseases (STD) control. This study examined the efficacy of contact tracing via patient self-referral in gonococcal and chlamydial cervicitis cases among adolescents, compared with the effectiveness of provider-referral. STUDY DESIGN: Adolescent females with culture-proven chlamydial or gonococcal cervicitis were the study subjects. This cohort study was done in an urban non-STD clinic setting. The subjects chose either provider-notification or self-notification method to inform their sex partner(s) in 2 months preceding the interview date. RESULTS: Two hundred and sixty-five eligible subjects (91% African-American, 9% white) were identified. One hundred and ninety-eight sex contacts were reported by 165 (62%) cases; no contact was elicited in the remaining 100 (38%). The follow-up data revealed that 129/198 (66%) contacts were informed: 63 contacts by 61 index cases, 54 contacts of 47 cases by the case manager, 9 by both methods, and 3 by unspecified means. History of treatment was obtained in 54 contacts, including 37% (23/63) of patient-notified contacts and 50% (27/54) of provider-notified contacts; these 54 contacts constituted 42% of informed contacts, or 27% of all named contacts. The mean number of sexual contacts treated per index case was 0.58 (27/47) for the provider-referral groups and 0.38 (23/61) for the self-referral groups. Successful contact tracing was documented in 19.3% (51/265) of all index cases, resulting in treatment of 54 contacts. CONCLUSION: This study demonstrates the need for more effective partner treatment strategies in adolescent STD cases.


Asunto(s)
Infecciones por Chlamydia/epidemiología , Chlamydia trachomatis , Trazado de Contacto , Gonorrea/epidemiología , Cervicitis Uterina/epidemiología , Adolescente , Alabama/epidemiología , Distribución de Chi-Cuadrado , Trazado de Contacto/métodos , Trazado de Contacto/estadística & datos numéricos , Femenino , Humanos , Masculino , Población Urbana/estadística & datos numéricos
13.
Am J Clin Nutr ; 58(3): 319-25, 1993 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-8237840

RESUMEN

The purpose of this study was to determine the effects of a nutrition-education program provided by a physician nutrition specialist in a family-practice residency program on residents' and faculty members' nutrition knowledge and nutrition-related patient care, their patients' perceptions of the importance of nutrition, and the physicians' dietary patterns. The nutrition specialist provided recommendations for nutrition patient-care practices to the physicians for 6 mo. Pre- and post-intervention assessments included 1) nutrition exams for physicians and patients, 2) patient questionnaires concerning attitudes towards nutrition, 3) chart reviews, and 4) diet records for physicians. The educational intervention caused a small but statistically significant (P < 0.01) increase in physicians' nutrition-knowledge scores and a significantly higher (P < 0.05) frequency of physicians discussing nutrition and recommending diets for their patients. Effects were greater among residents than among faculty members. The results suggest that a physician nutrition specialist can provide effective nutrition education within a residency program.


Asunto(s)
Medicina Familiar y Comunitaria/educación , Conocimientos, Actitudes y Práctica en Salud , Fenómenos Fisiológicos de la Nutrición , Registros de Dieta , Humanos , Internado y Residencia , Médicos , Especialización
14.
Phys Rev Lett ; 71(4): 509-512, 1993 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-10055294
15.
Psychosom Med ; 55(2): 212-8, 1993.
Artículo en Inglés | MEDLINE | ID: mdl-8475236

RESUMEN

Trainees were randomized into four groups: (1) control; (2) consult; (3) liaison; or (4) consult-plus-liaison to evaluate the psychiatric knowledge gained after two different training programs for primary care residents. Consult was a 1-month rotation on the Psychiatry Consultation Service. Liaison consisted of 31-hour workshops over 1 year. Consult-plus-Liaison refers to both training programs, experienced in consecutive years. An oral examination was administered before and after training. The analysis of variance and tests of simple effects revealed significant training effects for both groups. The effect size of training was greater for residents exposed to both programs, compared with either one alone. The two different training programs were both effective in improving the psychiatric knowledge of primary care residents and exposure to both programs proved superior to either one alone.


Asunto(s)
Medicina Interna/educación , Internado y Residencia , Trastornos Mentales/diagnóstico , Adulto , Educación , Evaluación Educacional , Femenino , Humanos , Masculino , Trastornos Mentales/psicología , Servicios de Salud Mental , Psiquiatría/educación , Recursos Humanos
16.
J Cancer Educ ; 7(2): 131-7, 1992.
Artículo en Inglés | MEDLINE | ID: mdl-1419577

RESUMEN

Third-year medical students participated in a program using a meal conference approach to teach ambulatory nutrition concepts called "Building Better Health Through Nutrition." The series of three interactive presentations was given during the required family medicine clerkship. A pretest and posttest were used to measure acquisition of nutrition knowledge. There was a statistically significant (P less than 0.05) average increase in posttest compared to pretest scores. Seventy percent of students rated the meal conference approach as "effective" or "very effective" and 76% stated that the series expanded their knowledge of nutrition's role in clinical medicine. We conclude that the meal conference format is an effective way to teach nutrition during the clinical years in medical school.


Asunto(s)
Atención Ambulatoria , Curriculum , Educación Médica , Ciencias de la Nutrición/educación , Facultades de Medicina , Enseñanza/métodos , Estados Unidos
17.
Am J Clin Nutr ; 54(6): 957-62, 1991 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-1957827

RESUMEN

Because limited information exists about nutrition training of residents, we studied the teaching practices of nationally recognized nutrition programs. Two hundred thirty-eight nutrition educators and 787 residency-program directors identified 160 institutions with strong nutrition training. The 23 highest-ranked programs were surveyed and 7 were visited. The results showed that 1) clinically active physician-nutritionist role models are the key elements in teaching residents clinical nutrition; 2) multidisciplinary nutrition support teams are valuable learning resources unless they function primarily as technical support services; 3) nutrition elective rotations, although highly effective, are taken by a minority of residents; 4) the nutrition curriculum should include practical learning materials and conferences; and 5) a research environment is important to attract qualified physician-nutritionist role models. A major deficit is teaching nutritionally based approaches to disease prevention in the ambulatory setting. Finally, a shortage of nutrition-oriented physician role models is probably the major constraint in teaching nutrition to residents.


Asunto(s)
Educación de Postgrado en Medicina , Internado y Residencia , Ciencias de la Nutrición/educación , Curriculum
18.
Am J Clin Nutr ; 52(3): 568-71, 1990 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-2393016

RESUMEN

A national survey was conducted by The American Society for Clinical Nutrition's Committee on Medical/Dental School and Residency Nutrition Education to assess the context in which nutrition training is provided in medical residency programs. Accreditation guidelines for residency programs suggested eight nutrition components that were endorsed by content experts for inclusion in residency training. Directors and nutrition educators from all accredited residencies in the United States were surveyed to determine the perceived importance of the components and the extent to which the components were actually present. The eight components appear to be relevant for exemplary nutrition training at the residency level. An important identified need is to train and involve more clinical-nutrition faculty members in residency programs.


Asunto(s)
Educación de Postgrado en Medicina/normas , Cuerpo Médico de Hospitales/educación , Ciencias de la Nutrición/educación , Internado y Residencia , Estados Unidos
19.
Am J Clin Nutr ; 50(4): 707-12, 1989 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-2801575

RESUMEN

The ASCN Committee on Medical/Dental School and Residency Nutrition Education conducted a series of activities to establish guidelines for nutrition core content in a medical school curriculum. These activities included mail surveys of medical-nutrition educators and a representative group of medical school curriculum administrators and a national consensus workshop of nutrition educators. Results indicated close agreement between the nutrition educators and curriculum administrators (r = 0.89, p less than 0.0001) on the importance ratings of 41 nutrition topics and on the number of hours of nutrition course work that medical schools should provide (44 vs 37 h, respectively, p = 0.14). There was consensus among the nutrition educators that 26 topics should be given priority ratings as essential for inclusion in medical course work. Further prioritization of these topics resulted in a listing of core content topics and subtopics to serve as a guide to administrators and educators for planning nutrition course work in a medical school curriculum.


Asunto(s)
Curriculum , Educación Médica/normas , Ciencias de la Nutrición/educación , Facultades de Medicina/normas , Enseñanza/normas
20.
Nutrition ; 5(1): 31-6, 1989.
Artículo en Inglés | MEDLINE | ID: mdl-2520254

RESUMEN

An examination previously developed and used for assessment of nutrition knowledge of medical students in the Southeastern Regional Medical-Nutrition Education Network was used to compare the effectiveness of a basic medical biochemistry course and a 58-hour required nutrition course. The examination was administered to a cohort of freshman students upon entry to medical school, after biochemistry, and then after nutrition. Two other student groups took the examination at the end of the sophomore and senior years, respectively. In the freshman cohort, mean nutrition knowledge scores increased slightly after biochemistry, (52% to 56%), which contained 37 nutrition-related lectures. The mean score of the cohort was 75% after the nutrition course. The sophomores scored 75% and the seniors 73%. These findings suggest 1) basic science courses such as biochemistry cannot be relied upon to add significantly to nutrition knowledge, and 2) a required freshman course can be an effective way to introduce basic and clinical nutrition with good retention of knowledge in subsequent years.


Asunto(s)
Bioquímica/educación , Educación de Postgrado en Medicina , Ciencias de la Nutrición/educación , Evaluación Educacional , Estudios de Evaluación como Asunto , Sudeste de Estados Unidos
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