Resumen El Premio Nobel de Física 2021 fue otorgado a Syukuro Manabe, Klaus Hasselmann y Giorgio Parisi por sus "contribuciones innovadoras a nuestra comprensión de los sistemas físicos complejos." Aquí repasamos algunas de las ideas y resultados que sirvieron de base científica al premio. También comentamos los trabajos de nuestro grupo de investigación sobre las propiedades de sistemas complejos de los láseres aleatorios y láseres de fibra aleatorios.

Abstract The 2021 Physics Nobel Prize was awarded to Syukuro Manabe, Klaus Hasselmann, and Giorgio Parisi for their "groundbreaking contributions to our understanding of complex physical systems." Here we review some of the ideas and results which served as the scientific basis to the award. We also comment on the works by our research group on the complex systems properties of random lasers and random fiber lasers.

Abstract: A review is presented on recent research that demonstrate the control of light-bylight in colloids containing silver-nanospheres (Ag-NS) and gold-nanorods (Au-NR). The presentation is based on experiments performed with pulsed lasers by exploiting the ultrafast electronic nonlinearity of samples exhibiting cubic-quintic nonlinearities. Guiding and confinement of light induced by optical vortex solitons in colloidal suspensions of Ag-NS, and nonlinear processes of light scattering, absorption and refraction in colloids with Au-NR were investigated in the experiments. The results are analyzed by numerical simulations based on modified nonlinear Schrödinger equations. The developments herein discussed are in the forefront of interest for plasmonic applications with metal nanoparticles.

Resumen: Este artículo presenta una revisión sobre investigaciones recientes que demuestran el control de la luz por luz en coloides que contienen nanoesferas de plata (Ag-NS) y nanobastones de oro (Au-NR). La presentación se basa en experimentos realizados con láseres pulsados mediante la explotación de la no linealidad electrónica ultrarrápida de las muestras que exhiben no linealidades cúbico-quínticas. Efectos tales como el guiamiento y confinamiento de la luz inducida por solitones ópticos, con estructura vortical, en suspensiones coloidales de AgNS, además de procesos no lineales de dispersión, absorción y refracción de la luz en coloides con Au-NR fueron investigados en los experimentos. Los resultados fueron analizados mediante simulaciones numéricas basadas en adaptaciones de la ecuación de Schrödinger no lineal. Los avances discutidos en el presente artículo están a la vanguardia del interés en aplicaciones plasmónicas con nanopartículas metálicas.

We report on the synthesis of single-crystalline tellurium nanowires with different aspect-ratios prepared via facile surfactant-assisted synthesis under mild conditions. Short and long Te nanowires were synthesized by the reduction of tellurium dioxide by hypophosphorous acid with the assistance of polyoxyethylene (23) laurylether and cetyltrimethylammonium bromide, respectively. We obtained uniform single-crystal Te nanowires with diameter below 30 nm and tunable length from 600 nm to 5 µm. Short and long Te nanowires showed remarkable nonlinear absorption and their third-order nonlinear optical properties were investigated by the Z-scan technique with single 80 ps laser pulses at 532 nm. For the first time, it was observed a distinguished switching behavior from saturated absorption to reverse saturated absorption as a function of the laser intensity in one-dimensional Te nanostructures. Although both short and long Te nanowires display such interesting behavior, the short ones exhibited superior optical limiting performance.

The influence of silver nanoparticles (Ag-NPs) on the optical properties of Bi2O3-GeO2 glasses was investigated aiming the characterization of their potential for applications in photonic devices. The samples were prepared by the melt-quenching technique starting from high purity oxides (GeO2, Bi2O3 and AgNO3). Heat-treatment during different times was performed to nucleate Ag-NPs. A transmission electron microscope was used to confirm the presence of Ag-NPs and to determine their sizes and composition. The glass network was studied by spontaneous Raman scattering. The optical absorption spectra showed an absorption band at ca. 500 nm associated to the bismuth ions, and a 7-fold enhancement of absorption was observed in the samples with Ag-NPs. Photoluminescence (PL) spectra were obtained by exciting the samples with a 808 nm laser. Maximum enhancements of ca. 100% of the PL band centered at 1300 nm and ca. 70% of the Raman spectrum were observed due to the nucleation of the Ag-NPs. The enhanced optical response of the samples with Ag-NPs is attributed to the growth of the local field on the isolated bismuth ions and clusters that are located in the vicinity of the nanoparticles. The results illustrate the large potential of Bi2O3-GeO2 with Ag-NPs to be used in photonic devices.

We present a review of recent works on optically investigated thermal effects in crystalline and amorphous materials doped with trivalent rare-earth (RE) ions. The paper describes how the frequency upconversion (UC) photoluminescence (PL) technique is used to investigate the thermal behavior of samples and how to perform optical measurements of temperature. The UC technique is based on the sequential multiphoton absorption phenomenon that leads to anti-Stokes type emission. By measuring the relative intensity between UC emissions from thermally coupled RE energy levels, the absolute temperature of a sample can be determined. Research in this area is motivated by the possible uses of UC for basic characterization of materials and for noncontact thermometry using nanoscale devices as well as for biological and medical studies. Examples based on the application of bulk materials and nanopowders doped with several RE ions are presented.

Foi observado na natureza o consumo da carniça de um tapiti (Sylvilagus brasiliensis) por uma fêmea reintroduzida da cutia Dasyprocta leporina. Neste estudo, além da descrição desse evento, é feita uma revisão de outras evidências de consumo de vertebrados por cutias. A maioria dos estudos que descreveram esse comportamento foi realizada em cativeiro. Os animais predados incluíram aves e pequenos roedores, que foram mortos pelas cutias em algumas ocasiões. Esse padrão sugere que esse não é um comportamento anômalo para o gênero, refletindo seus hábitos onívoros. Esse comportamento pode trazer vantagens fisiológicas para esses animais, de forma que novos estudos devem focar na variação temporal do uso desse recurso, relacionando-o com períodos de escassez e com a estação reprodutiva dos animais, onde a necessidade de alimentos de alta qualidade energética pode ser maior.

The consumption of the carrion of a tapiti by a reintroduced female Dasyprocta leporina was observed in the wild. Herein, besides describing this event, we reviewed other evidence of vertebrate consumption by agoutis. Most of the studies describing this behaviour have been carried out in captivity. The preyed animals included birds and small rodents, which were sometimes killed by agoutis. This pattern suggests that this is not an anomalous behaviour for the genus, reflecting its omnivorous habits. This behaviour can be a physiologically sound feeding strategy, so new studies should focus on the temporal variation in the consumption of this resource, possibly related to food scarcity periods or to reproductive seasons, when the need for high-quality food tends to increase.

Background: Anterograde mechanical colon cleansing is routinely done before colorectal surgery. However there is no firm evidence about its usefulness. Aim: To assess the usefulness of anterograde mechanical colon cleansing in colon surgery. Patients and Methods: Participants requiring elective colorectal surgery were randomized to receive anterograde mechanical bowel cleansing with two doses of oral sodium phosphate (Oral fleet*) or a liquid diet 24 hours prior to surgery, after signing an informed consent. Both groups received antimicrobial prophylaxis. Problems associated with bowel cleansing, subjective assessment ofbowel preparation by the surgeon and postoperative complications were recorded. Results: One hundred twenty two participants were studied (73 females). Fifty three percent of patients had concomitant diseases such as hypertension and diabetes mellitus. Sixty patients were subjected to anterograde bowel cleansing and 62 were ascribed to the liquid diet group. Surgeons evaluated colon cleansing as good in 49 and 37 patients with and without anterograde mechanical cleansing, respectively and as regular in 8 and 23 patients, respectively (χ2 = 9.1 p = 0.01). Tolerance to cleansing was evaluated as good, fair and poor by 50, 30 and 20% of patients, respectively. One patient had a bowel obstruction associated with the use of sodium phosphate. Postoperative complications occurred in 14 and 23 patients subjected or not to cleansing, respectively (p = 0.06). Septic complications occurred in 11 and 3 cases with and without colon cleansing, respectively (p < 0.01). Conclusions: Anterograde mechanical colon cleansing was associated with a higher incidence of septic complications in this series of patients.

Introducción: El uso de Ia preparación mecánica anterógrada (PMA) es una práctica rutinaria en cirugia colorrectal pero con escasas bases en Ia evidencia científica. Objetivo: Determinar Ia utilidad de Ia PMA en una serie prospectiva y aleatoria de cirugía colorrectal electiva. Resultados: La serie corresponde a 122 pacientes, 60 de Ios cuales recibe PMA. Los datos epidemiológicos muestran que Ios grupos son comparables. En esta serie se encuentra un riesgo de morbilidad global aumentado al doble en Ios pacientes que reciben PMA, así como un riesgo de infección superficial del sitio quirúrgico seis veces mayor. No se encuentran diferencias en Ias infecciones profundas, dehiscencia de anastomosis ni en Ias reintervenciones. Las complicaciones asociadas a Ia PMA se presentaron sólo en un caso, 10 que no alcanza significación estadística. Conclusiones: De acuerdo a nuestros resultados, no sejustifica Ia utilización rutinaria de PMA.

Background: Five years survival after surgery for incipient gastric cancer is high. However there is a paucity of information for longer follow up periods. Aim: To analyze long term survival after surgery for incipient gastric cancer. Material and Methods: Review of medical records of patients operated for incipient gastric cancer with an oncologic follow up of 10 years or more. Results: Data from 161 patients, aged 25 to 88 years, 55% males, was retrieved. Eight percent of tumors were multifocal and a mean of 17 lymph nodes per patient, were dissected. There was lymph node involvement in 11 and 3% of submucosal and mucosal lesions, respectively. Ten years survival was 78%. The causes of death were medical in 68%, another cancer in 18% and gastric cancer in 18%. Incipient gastric cancer 10 years specific survival was 95%. The figures for submucocal and mucosal lesions were 98 and 91% respectively. The figures for patients with or without lymph node involvement were 75 and 94% respectively. Conclusions: Ten years mortality due to incipient gastric cancer is exceedingly low and other causes will be the cause of death among these patients.

Introducción: Los resultados del tratamiento quirúrgico del cáncer gástrico incipiente (CGI) son satisfactorios en el seguimiento a 5 años. Sin embargo, en Chile, se desconoce el comportamiento a mayor plazo. Objetivo: Describir los resultados del tratamiento quirúrgico del CGI en el seguimiento mayor a 10 años. Material y Método: Revisión retrospectiva de los pacientes operados por CGI con seguimiento oncológico mayor a 10 años. El análisis de supervivencia se realizó a través de curvas Kaplan-Meier y el análisis univariado con el test de Fisher. Se consideró significancia estadística con p < 0,05. Resultados: La serie está constituida por 161 pacientes. La edad promedio fue 57 años. Un 7,6% son cánceres multifocales. Se disecaron 17,4 linfonodos en promedio por paciente. Se identificó compromiso linfático en 11,5% de las lesiones submucosas y 2,9% de las mucosas. La supervivencia general fue de 78,3% a 10 años. La mortalidad se distribuye: 67,7% por patología médica, 14,5% por otro cáncer y 17,7% por CGI. La supervivencia específica por CGI fue de 94,7% a 10 años. Según profundidad: las lesiones mucosas fue de 98% y de las submucosas de 91,3% (p = 0,186). La supervivencia en ausencia de ganglios comprometidos fue de 96,4% y 75% en presencia de adenopatías (p = 0,026). La muerte acumulada por CGI a los 10 años fue de 3,72%. Conclusión: El seguimiento a 10 años o más de los pacientes operados por CGI mostró que es más probable la muerte por otra causa que por cáncer gástrico, el riesgo de muerte por CGI persiste en el tiempo.

Background: The systematic dissection of the surgical piece, performed by the surgeon during surgical treatment of gastric cancer, gives information about borders and lymph node involvement. Aim: To determine the concordance between the findings of the surgeon during initial dissection and the final pathological report. Material and Methods: Prospective study of 48 patients aged 64 ± 10 years (74% males) subjected to curative surgery for gastric cancer. Patients were staged according to 2010 TNM classification. Stomach size from the lesser curvature, oral and caudal limits, macroscopic aspect, tumor diameter and lymph node involvement were determined by the surgeon observing the surgical piece. The concordance of this observation with the final pathological report was assessed. Results: Fifty nine percent of patients were subjected to a total gastrectomy and there was a mean of 30 lymph nodes excised. There was a good concordance between surgeon observation and final pathological report for tumor depth (Kappa = 0.64), macroscopic aspect (Kappa = 0.69) and tumor size (Lin = 0.84). There was a bad concordance for lymph node involvement (Kappa = 0.21). The percentage of retraction of lesser curvature length was 24%, 30% for oral and 22% for caudal limits. Conclusions: There is a good concordance between surgeon observation and pathological report for macroscopic aspect, tumor size and depth but the concordance for lymph node involvement is bad.

Introducción: La disección de la pieza operatoria (PO) en forma sistemática en la cirugía por cáncer gástrico (CG) permite al cirujano obtener información de los bordes, compromiso linfonodal y estandarizar. Objetivos: 1) Determinar la concordancia de los hallazgos de la PO disecada por el cirujano y el informe patológico final; 2) Determinar el porcentaje de retracción del estómago; 3) Mostrar una forma de registrar la PO en el CG. Material y Método: Estudio prospectivo de los pacientes operados con intención curativa desde septiembre de 2009 hasta mayo de 2010. Se etapificó con TNM de 2010. De la PO se registró el tamaño del estómago por curvatura menor, límite oral (LO), límite caudal (LC), profundidad, aspecto macroscópico, diámetro tumoral, grupos ganglionares comprometidos y cantidad de ganglios comprometidos. Se compararon estas variables con el informe patológico. El análisis de concordancia se realizó con el test de Kappa y el test de Lin. Resultados: Fueron estudiados 48 pacientes, 74% hombres, la edad promedio fue 63,7 años (DE 9,8), 59,5% fueron gastrectomías totales. El promedio de ganglios disecados fue 30,18 (DE 11,8). Se obtiene una buena concordancia para la profundidad del tumor (Kappa = 0,64), aspecto macroscópico (Kappa = 0,69) y tamaño tumoral (Lin = 0,84). Y una mala concordancia para el compromiso ganglionar (Kappa = 0,21). El porcentaje de retracción del largo por curvatura menor fue 24,3%, del LO fue 30,1%, del LC fue 22%. Conclusión: La concordancia de la PO es buena en la profundidad, aspecto macroscópico del tumor y diámetro tumoral, pero es mala en el compromiso ganglionar. Se determina que la retracción del estómago es mayor al 24%.

Background: Anterograde mechanical bowel cleansing is a common practice in colorectal surgery. However it can produce physiological disturbances and can be associated to a higher frequency of septic complications. Aim: To evaluate the appearance of histological alterations in the colon wall, associated to anterograde bowel cleansing. Material and methods: All patients subjected to elective colon surgery were randomized to a group with and other group without anterograde mechanical bowel cleansing before surgery. Patients subjected to preoperative radiotherapy and those that were subjected to bowel cleansing the week previous to surgery, were excluded. A sample was obtained from normal colon mucosa, far from the lesion that motivated surgery, for pathological study. The pathologist was unaware of the group assignation of patients. Results: Thirty four patients were studied. Eighteen (nine women) were randomized to receive mechanical bowel cleansing, 14 (eight women) did not receive cleansing and two were excluded from the study. No significant pathological bowel wall alterations were detected in the group subjected to mechanical cleansing. Conclusions: No pathological alterations of the bowel wall, attributed to anterograde bowel cleansing, were detected in this group of patients

Introducción: La preparación mecánica anterograda de colon en cirugía electiva es una práctica común utilizada en distintas operaciones sobre el segmento distal del tubo digestivo. La limpieza intestinal ha demostrado provocar alteraciones fisiológicas significativas y algunos autores han relacionado su uso con una mayor incidencia de complicaciones sépticas, aunque sin demostrar un sustrato anatómico o histológico que avale estas afirmaciones. Objetivo: Demostrar la aparición de alteraciones histológicas asociadas al uso de preparación mecánica anterograda en cirugía colorrectal electiva. Material y método: Durante un periodo de 10 meses se incluyeron en este estudio todos los pacientes sometidos a cirugía electiva de colon. Se excluyeron los pacientes que recibieron radioterapia pre operatoria y quienes recibieron preparación mecánica la semana previa a la cirugía. Los pacientes fueron randomizados en dos grupos: con y sin preparación de colon. Un patólogo evaluó las alteraciones histológicas en mucosa sana en forma ciega. Los datos fueron analizados con el programa Stata 8.0. Resultados: Participaron 34 pacientes en este estudio, de los que se excluyeron 2 por no haber sido resecados, ambos en el grupo que recibió preparación mecánica. El estudio de siete parámetros no demostró alteración significativa en los pacientes que recibieron preparación mecánica anterograda (p > 0,05). Conclusión: En esta serie prospectiva y aleatoria no se encontraron alteraciones histológicas atribuibles al uso de la preparación mecánica anterograda

The presence of an acute appendicitis in an incarcerated inguinal hernia, termed Amyand's hernia, is an uncommon and rare condition estimated to be found in approximately 0.13% of adult inguinal hernia repairs. The usual clinical presentation is as a complicated inguinal hernia; this is why the preoperative diagnosis of acute appendicitis requires a high clinical suspicion, even though the diagnosis of Amyand's hernia is done mainly during surgery. Computed tomography is a good diagnostic method. The treatment is surgical, and consists of an appendectomy with primary repair of the hernia. Synthetic mesh should not be used in the repair of contaminated abdominal wall defects, because the prosthetic material can increase the inflammatory response and result in wound infection and a possible appendiceal stump fistula. We report a 75 years old man who presented with a complicated inguinal hernia, in whom the diagnosis of acute appendicitis was made during surgery after opening the hernia sac

La presencia de apendicitis aguda en una hernia inguinal es un hecho infrecuente, con un 0,13% de los casos. Esta rara condición se conoce como Hernia de Amyand. La forma de presentación habitual es la de una hernia inguinal complicada. Es por este motivo que el diagnóstico preoperatorio de apendicitis aguda requiere de una alta sospecha clínica, realizándose mayoritariamente durante la cirugía. El estudio de imágenes, en particular la Tomografía Axial Computada, ha sido utilizado para plantear este diagnóstico. El tratamiento recomendado es la apendicectomía y la reparación primaria de la hernia en el mismo tiempo operatorio. No se debe utilizar prótesis por el riesgo de infección y fístula del muñón apendicular. Debido a lo excepcional de esta patología, presentamos el caso de un hombre de 75 años que se manifestó como una hernia inguinal complicada y cuyo diagnóstico de apendicitis se realizó en pabellón luego de abrir el saco