653 research outputs found
Larger crises, slower recoveries: the asymmetric effects of financial frictions
It is well known that movements in lending rates are asymmetric; they rise quickly and sharply, but fall slowly and gradually. Not known is the fact that the asymmetry is stronger the less developed a country's financial system is. This new fact is here documented and explained in a model with an endogenous flow of information about economic conditions. The stronger asymmetry in less developed countries stems from their greater financial system frictions, such as monitoring and bankruptcy costs, which first magnify jumps of lending rates and then delay their recoveries by restricting the generation of information after the crisis. A quantitative exploration of the model shows the data are consistent with this explanation.Financial crises ; Developing countries
Fragility of reputation and clustering of risk-taking
Concerns about constructing and maintaining good reputations are known to reduce borrowers' excessive risk-taking. However, I find that the self-discipline induced by these concerns is fragile, and can break down without obvious changes in economic fundamentals. Furthermore, in the aggregate, breakdowns are clustered among borrowers with intermediate and good reputations, which can exacerbate an economy's weakness and contribute to a broad economic crisis. These results come from an aggregate dynamic global game analysis of reputation formation in credit markets. The selection of a unique equilibrium is accomplished by assuming that borrowers have incomplete information about economic fundamentals.Risk
Keeping watch over Colombia’s slumbering volcanoes
The Volcanological and Seismological Observatories of Manizales, Pasto and Popayan (Colombian Geological Survey) monitor and study the active volcanoes of Colombia using seismological, geodetic, geochemical and other techniques. Since 2009, permanent GNSS stations have been installed to complement classical geodetic measurements (e.g., tilt, EDM). At the moment, there are a total of 20 GNSS stations installed at Nevado del Ruiz, Cerro Machín, Puracé and Galeras volcanoes.
Nevado del Ruiz has remained the most dynamic of the active Colombian volcanoes since its tragic eruption of 13 November 1985. The most significant deformation occurred between 2007 and 2012, when inflation, associated with magma migration and several small to moderate explosive eruptions in 2012 (VEI less or equal to 3), was observed.
Galeras has experienced more than 25 moderate Vulcanian eruptions (VEI less or equal to 3) since 1989. In particular, the deformation network detected significant signals associated with magma migration and the extrusion of lava domes in 1991, 2005, 2008 and 2012.
Puracé volcano has been the site of more than 10 minor eruptive episodes (VEI=2) in the past century, most recently in 1977. Monitoring of this volcano started in 1994. Unrest at Puracé since that time has been characterized by significant increases in seismic activity but with little or no deformation.
We employ GAMIT/GLOBK to process GPS data from the monitoring network with support from the Volcano Disaster Assistance Program (U.S. Geological Survey). Additionally, differential processing is carried out using the commercial package Trimble 4D Control. Preliminary results for 2012 show no significant deformation at Puracé and Galeras volcanoes. On the other hand, the time series from Nevado del Ruiz shows a minor inflation (2-4 cm/yr) associated with the eruptive activity of 2012
Textile characteristics of fiber from Huacaya alpacas (Vicugna pacos)
Fiber from alpacas represents a substantial component of economic output for South American countries. In this study it determined the textile characteristics of fibers obtained from Huacaya alpacas raised at the South American Camelids Research and Development Center-Lachocc (CRDC-Lachocc) located at The National University of Huancavelica (UNH). Fleece samples were obtained from the mid-side rib area of 74 white alpacas (42 females and 32 males) of varying ages. The Average Fiber Diameter (AFD), Standard Deviation of the Average Fiber Diameter (SDAFD), Fiber Diameter Coefficient of Variation (FDCV), Comfort Factor (CF) and Staple Length (SL) were measured as textile characteristics and related to sex and age group. Most of the fleece samples could be classified as baby alpaca fleece according to the Peruvian Technical Standard classification (231.301.2014). Sex had no influence on any textile characteristic (p > 0.05). Meanwhile, age affected only AFD and CF (p < 0.05). Together the results indicated that alpacas farmed at CRDC-Lachocc had good potential to produce high quality fibers
Influence of the Synthesis Method on the Preparation Composites Derived from TiO2-LDH for Phenol Photodegradation
Three different TiO2 catalysts are prepared using different methods. MgAl-CO32− layered double hydroxides (LDH) were obtained by the sol-gel method. In the preparation of the composites, the three photocatalysts were combined with LDH following different methodologies. The composites were characterized using X-ray diffraction (XRD), specific surface area (SA), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The influence of the synthesis method on the preparation of the composites was evaluated by analyzing their photocatalytic activity against phenol as a model organic pollutant under UV irradiation. The photocatalytic activity of the composites improves when the chemical interaction, determined by XPS, between the TiO2 and the LDH decreases. The same happens when the ratio of the anatase-rutile phases, determined by XRD, approaches optimum (80:20%). The effect of the composite concentration in the solution (0.5–2.0 g/L) was investigated, and the light-shielding phenomenon due to high composite concentration decreases the phenol photodegradation. The reduction of photocatalytic activity in reuse cycles is due to loss and partial deactivation of the material. The elimination of phenol is attributed primarily to the photocatalytic process due to the generation of ●OH radicals and to a lesser extent the adsorption process also present in the samples
Nontrivial eigenvalues of the Liouvillian of an open quantum system
We present methods of finding complex eigenvalues of the Liouvillian of an
open quantum system. The goal is to find eigenvalues that cannot be predicted
from the eigenvalues of the corresponding Hamiltonian. Our model is a T-type
quantum dot with an infinitely long lead. We suggest the existence of the
non-trivial eigenvalues of the Liouvillian in two ways: one way is to show that
the original problem reduces to the problem of a two-particle Hamiltonian with
a two-body interaction and the other way is to show that diagram expansion of
the Green's function has correlation between the bra state and the ket state.
We also introduce the integral equations equivalent to the original eigenvalue
problem.Comment: 5 pages, 2 figures, proceeding
Smart sensing of the multifunctional properties of magnetron sputtered across the amorphous-crystalline transition
Molybdenum disulfide, , is a next-generation semiconductor and is
frequently integrated into emergent optoelectronic technologies based on
two-dimensional materials. Here, we present a method that provides direct
optical feedback on the thickness and crystallinity of sputter-deposited
down to the few-layer regime. This smart sensing enables tracking the
material's functional properties, such as excitonic response, sheet resistance,
and hardness across the amorphous-crystalline transition. To illustrate the
potential of such feedback-controlled fabrication, we realized -based
hyperbolic metamaterials (HMM) with controllable optical topological
transitions and hardness.Comment: 17 pages, 4 figures, 68 references. Supplementary available with 16
pages, 8 figures, and 10 reference
Application of the laboratory risk indicator for necrotizing fasciitis score for patients with hand infection in Mexican population
Background: Necrotizing fasciitis (NF) is a severe form of soft tissue infection, early diagnosis, and surgical intervention are direct factors in mortality, it may arise from many infectious aetiologies, at our hospital in Mexico city, it is not uncommon that hand infection patients progress to NF, that in many cases its recognition and treatment may also be delayed, resulting in fatal outcomes. Wong et al in 2004 introduced a laboratory risk indicator for necrotizing fasciitis (LRINEC score) that utilizes common laboratory values of patients with clinical infection and stratifies them by their risk of developing NF, so the aim of our study was to validate this tool in Mexican population.
Methods: We reviewed all patients with an initial diagnosis of hand infection admitted at the emergency department of our hospital in Mexico City, from April 2020 to March 2022 and examined the LRINEC score at admission, post-debridement, and at the end of the hospitalization to evaluate its usefulness in our population.
Results: The LRINEC score at cut-off ≥6 reported sensitivity for the diagnosis of NF of 35.71% (95% CI 12.76-64.86%), specificity of 100% (95% CI 78.2-100%), positive predictive value of 100% (95% CI 71-100%), and negative predictive value of 62.5% (95% CI 53.01-71.12%).
Conclusions: The LRINEC score is a useful tool to distinguish NF from other soft tissue infections, but it is not helpful for early recognition of NF alone, LRINEC score could predict worse hospital outcomes in patients with NF and identify the high-risk patients.
Propiedades psicométricas de la versión en español del Cuestionario de Necesidades Interpersonales de 12 ítems en pacientes con síndrome de fibromialgia.
Según la teoría interpersonal del suicidio, la pertenencia frustrada
y la carga percibida son elementos clave en el desarrollo de la ideación
suicida. El Cuestionario de necesidades interpersonales (INQ) fue diseñado
para evaluar el grado de frustración de estas dos necesidades interpersonales
relacionadas con la ideación suicida. El objetivo de este estudio
fue analizar las propiedades psicométricas de una adaptación al español del
INQ-12 en pacientes con fibromialgia. Un análisis factorial exploratorio (n
= 180) y un análisis factorial confirmatorio (n = 179) fueron realizados en
dos submuestras seleccionadas al azar. El primer análisis llevó a la eliminación
de dos ítems, mientras que el segundo confirmó el ajuste de la estructura
propuesta de dos factores. La fiabilidad estimada mediante el coeficiente
alfa de Cronbach y el coeficiente Spearman-Brown fue adecuada.
Para obtener evidencias de validez basadas en la relación con otros variables,
se utilizaron tres variables relacionadas con el suicidio. Además, se utilizó
un grupo control (n = 99) para contrastar los promedios de las puntuaciones
INQ como evidencia de validez basada en puntajes diferenciales.
Estos hallazgos respaldan la utilidad de la versión española del INQ-10 para
evaluar el grado de frustración de estas necesidades interpersonales en
pacientes con fibromialgia.According to the interpersonal theory of suicide, thwarted belongingness
and perceived burdensomeness are key elements in the development
of suicidal ideation. The Interpersonal Needs Questionnaire
(INQ) was developed to assess the degree of frustration of these two interpersonal
needs related to suicidal ideation. This study aims to analyze
the psychometrics properties of a Spanish adaptation of INQ-12 in fibromyalgia
patients. Exploratory factor analysis (n = 180) and confirmatory
factor analysis (n = 179) were performed in two randomly selected subsamples.
The first analysis leads to the elimination of two items, whereas
the second one confirmed the fit of the proposed two-factor structure.
The reliability estimated using the Cronbach´s alpha coefficient and the
Spearman-Brown coefficient was adequate. To obtain further validity evidence
based on the relationship with other variables three variables were
used. Moreover, a control group (n = 99) was used to contrast the means
of INQ scores as evidence of validity based on differential scores. These
findings support the usefulness of the Spanish version of the INQ-10 for
assessing the degree of frustration of these interpersonal needs in patients
with fibromyalgia
- …