Superradiance mediated by Graphene Surface Plasmons

We demonstrate that the interaction between two emitters can be controlled by means of the efficient excitation of surface plasmon modes in graphene. We consider graphene surface plasmons supported by either two-dimensional graphene sheets or one-dimensional graphene ribbons, showing in both cases that the coupling between the emitters can be strongly enhanced or suppressed. The super- and subradiant regimes are investigated in the reflection and transmission configurations. Importantly, the length scale of the coupling between emitters, which in vacuum is fixed by the free space wavelength, is now determined by the wavelength of the graphene surface plasmons that can be extremely short and be tuned at will via a gate voltage

Alcohol, binge drinking and associated mental health problems in young urban Chileans

OBJECTIVE: To explore the link between alcohol use, binge drinking and mental health problems in a representative sample of adolescent and young adult Chileans. METHODS: Age and sex-adjusted Odds Ratios (OR) for four mental wellbeing measures were estimated with separate conditional logistic regression models for adolescents aged 15-20 years, and young adults aged 21-25 years, using population-based estimates of alcohol use prevalence rates from the Chilean National Health Survey 2010. RESULTS: Sixty five per cent of adolescents and 85% of young adults reported drinking alcohol in the last year and of those 83% per cent of adolescents and 86% of young adults reported binge drinking in the previous month. Adolescents who reported binging alcohol were also more likely, compared to young adults, to report being always or almost always depressed (OR 12.97 [95% CI, 1.86-19.54]) or to feel very anxious in the last month (OR 9.37 [1.77-19.54]). Adolescent females were more likely to report poor life satisfaction in the previous year than adolescent males (OR 8.50 [1.61-15.78]), feel always or almost always depressed (OR 3.41 [1.25-9.58]). Being female was also associated with a self-reported diagnosis of depression for both age groups (adolescents, OR 4.74 [1.49-15.08] and young adults, OR 4.08 [1.65-10.05]). CONCLUSION: Young people in Chile self-report a high prevalence of alcohol use, binge drinking and associated mental health problems. The harms associated with alcohol consumption need to be highlighted through evidence-based prevention programs. Health and education systems need to be strengthened to screen and support young people. Focussing on policy initiatives to limit beverage companies targeting alcohol to young people will also be needed

Trends and outcome of neoadjuvant treatment for rectal cancer: A retrospective analysis and critical assessment of a 10-year prospective national registry on behalf of the Spanish Rectal Cancer Project

Introduction: Preoperative treatment and adequate surgery increase local control in rectal cancer. However, modalities and indications for neoadjuvant treatment may be controversial. Aim of this study was to assess the trends of preoperative treatment and outcomes in patients with rectal cancer included in the Rectal Cancer Registry of the Spanish Associations of Surgeons. Method: This is a STROBE-compliant retrospective analysis of a prospective database. All patients operated on with curative intention included in the Rectal Cancer Registry were included. Analyses were performed to compare the use of neoadjuvant/adjuvant treatment in three timeframes: I)2006–2009; II)2010–2013; III)2014–2017. Survival analyses were run for 3-year survival in timeframes I-II. Results: Out of 14, 391 patients, 8871 (61.6%) received neoadjuvant treatment. Long-course chemo/radiotherapy was the most used approach (79.9%), followed by short-course radiotherapy ± chemotherapy (7.6%). The use of neoadjuvant treatment for cancer of the upper third (15-11 cm) increased over time (31.5%vs 34.5%vs 38.6%, p = 0.0018). The complete regression rate slightly increased over time (15.6% vs 16% vs 18.5%; p = 0.0093); the proportion of patients with involved circumferential resection margins (CRM) went down from 8.2% to 7.3%and 5.5% (p = 0.0004). Neoadjuvant treatment significantly decreased positive CRM in lower third tumors (OR 0.71, 0.59–0.87, Cochrane-Mantel-Haenszel P = 0.0008). Most ypN0 patients also received adjuvant therapy. In MR-defined stage III patients, preoperative treatment was associated with significantly longer local-recurrence-free survival (p < 0.0001), and cancer-specific survival (p < 0.0001). The survival benefit was smaller in upper third cancers. Conclusion: There was an increasing trend and a potential overuse of neoadjuvant treatment in cancer of the upper rectum. Most ypN0 patients received postoperative treatment. Involvement of CRM in lower third tumors was reduced after neoadjuvant treatment. Stage III and MRcN + benefited the most

Caracterización multianalítica de meteorito marciano NWA2975 mediante CF-LIBS, fluorescencia de rayos X y espectroscopía Raman

La caracterización isotópica y elemental de los meteoritos de Marte ha permitido determinar la cronología de los procesos de formación del planeta y avanzar en la comprensión de su evolución biogeoquímica e hidrológica. Los meteoritos más abundantes son las rocas de origen ígneo, como las shergottitas. Los estudios petrológicos y geoquímicos previos del meteorito Northwest Africa 2975 (NWA 2975), revelaron que se trata de una roca volcánica de grano medio, entre subofítica y granular, compuesta predominantemente por piroxenos (57,3 vol.%) y plagioclasa (38,3 vol. %) completamente enmascarados con fases opacas (2,7 vol.%) y fosfatos (1,7 vol.%) [1]. El instrumento SuperCam a bordo del rover Perseverance (misión MARS 2020 de la NASA) está equipado con técnicas atómicas y moleculares (incluyendo LIBS y Raman) para la detección y análisis a distancia de muestras geológicas en la superficie del Planeta Rojo. La capacidad de estas técnicas se ha demostrado ampliamente en la caracterización de rocas, minerales y suelos en varias misiones espaciales. En el presente trabajo, se analizó un fragmento del meteorito NWA 2975 mediante un sistema de micro-LIBS con el objetivo de revelar su composición química elemental. Debido a la heterogeneidad intrínseca de la muestra, se analizaron diferentes posiciones de su superficie. El análisis cuantitativo de los elementos principales (Si, Al, Fe, Mg, Mn, Ca y O) y de otros elementos menores se llevó a cabo utilizando la metodología Calibration-Free [2]. Los resultados sugieren la presencia de piroxenos como principal componente mineral en las posiciones inspeccionadas, aunque también se pueden encontrar otras fases minerales como la plagioclasa. La información extraída del análisis LIBS se ha comparado con la de fluorescencia de rayos X (XRF) y la espectroscopia Raman. El uso combinado de diferentes técnicas espectroscópicas ha permitido obtener una mejor interpretación de los resultados composicionales.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech