Precolonial institutions and deforestation in Africa

We find that local institutions inherited from the precolonial era continue to play an important role in natural resource governance in Africa. Using satellite image data, we find a significant and robust relationship between deforestation and precolonial succession rules of local leaders (local chiefs). In particular, we find that those precolonial areas where local leaders were appointed by ‘social standing’ have higher rates of deforestation compared to the base case of hereditary rule and where local leaders were appointed from above (by paramount chiefs). While the transmission mechanisms behind these results are complex, we suggest that areas where local leaders were appointed by social standing are more likely to have poorer institutions governing local leadership and forest management.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.landusepol.2015.10.03

Condiciones de trabajo y morbilidad entre mineros del carbón en Guachetá, Cundinamarca: La mirada de los legos

Introduction: Investigations in Colombia about work and health conditions in coal mining are scarce and few have focused on the perception of the exposed population and their behaviors in response to inherent risks. Objective: To determine the association between work conditions and the perception of morbidity among coal miners in Guachetá, Cundinamarca. Materials and methods: A cross-sectional study was performed with 154 workers selected randomly from the total registered with the municipality. Information about social and demographic characteristics and work and health conditions in the mines was gathered. The prevalence was estimated for respiratory, musculoskeletal and auditory disorders. The associations between certain work conditions, and events with a prevalence over 30% were explored using bivariate and multivariate analyses with Poisson regressions with robust variance. Results: Workers were mostly men. Ages ranged from 18 to 77 years. Most frequently reported health problems were: back pain (46.1 %), pain in an upper limb (40.3%), pain in a lower limb (34.4 %), andrespiratory (17.5 %) and auditory problems (13.6 %). Significant differences in perception were found depending on time on the job and underground or ground work conditions. Conclusions: The most recognized risks were those associated with musculoskeletal disorders since they were closer in time to the work performed (time discount). Some actions to identify psychological traits are proposed in order to improve risk perception among coal miners

Spontaneous Magnetization and Electron Momentum Density in 3D Quantum Dots

We discuss an exactly solvable model Hamiltonian for describing the interacting electron gas in a quantum dot. Results for a spherical square well confining potential are presented. The ground state is found to exhibit striking oscillations in spin polarization with dot radius at a fixed electron density. These oscillations are shown to induce characteristic signatures in the momentum density of the electron gas, providing a novel route for direct experimental observation of the dot magnetization via spectroscopies sensitive to the electron momentum density.Comment: 5 pages (Revtex4), 4 (eps) figure

Excited states of Na nanoislands on the Cu(111) surface

Electronic states of one monolayer high Na nanoislands on the Cu(111) surface are studied as a function of the nanoisland size. Properties of nanoislands such as one-electron states, the electron density, and the associated potential are obtained self-consistently within the density-functional formalism using a one-dimensional pseudopotential for the Cu(111) substrate and the jellium model for Na. A wave packet propagation method is used to study the energies and lifetimes of quasistationary states localized at Na islands. For very large islands, island-localized states merge into the two-dimensional continuum of the Na quantum well state. Thus, we assign the quasistationary states studied as arising from the quantization of the two-dimensional quantum well continuum due to the finite island size. The scattering at the island boundaries results in the energy-conserving resonant electron transfer into the continuum of the substrate states broadening the island-localized states into resonances.Peer reviewe

First-Principles Study on Peierls Instability in Infinite Single-Row Al Wires

We present the relation between the atomic and spin-electronic structures of infinite single-row atomic wires made of Al atoms during their elongation using first-principles molecular-dynamics simulations. Our study reveals that the Peierls transition indeed occurs in the wire with magnetic ordering: it ruptures to form a trimerized structure with antiferromagnetic ordering and changes from a conductor to an insulator just before forming a linear wire of equally-spaced atoms. The formation of the trimerized wire is discussed in terms of the behavior of the $\sigma$-symmetry bands of the Al wire.Comment: 10 pages, 4 figure

Magnetic phenomena in 5d transition metal nanowires

We have carried out fully relativistic full-potential, spin-polarized, all-electron density-functional calculations for straight, monatomic nanowires of the 5d transition and noble metals Os, Ir, Pt and Au. We find that, of these metal nanowires, Os and Pt have mean-field magnetic moments for values of the bond length at equilibrium. In the case of Au and Ir, the wires need to be slightly stretched in order to spin polarize. An analysis of the band structures of the wires indicate that the superparamagnetic state that our calculations suggest will affect the conductance through the wires -- though not by a large amount -- at least in the absence of magnetic domain walls. It should thus lead to a characteristic temperature- and field dependent conductance, and may also cause a significant spin polarization of the transmitted current.Comment: 7 pages, 5 figure

TBCCD1, a new centrosomal protein, is required for centrosome and Golgi apparatus positioning

In animal cells the centrosome is actively positioned at the cell center in close association with the nucleus. The mechanisms responsible for this are not completely understood. Here we report the first characterization of human TBCCD1, a protein related to tubulin cofactor C. TBCCD1 localizes at the centrosome and at the spindle midzone, midbody and basal bodies of primary and motile cilia. Knockdown of TBCCD1 in RPE-1 cells caused the dissociation of the centrosome from the nucleus and disorganization of the Golgi apparatus. TBCCD1 depleted cells are larger, less efficient in primary cilia assembly and their migration is slower in wound-healing assays. However, the microtubule nucleating activity of the centrosome is not affected by TBCCD1 silencing. We propose that TBCCD1 is a key regulator of centrosome positioning and consequently of internal cell organization

Model study of adsorbed metallic quantum dots: Na on Cu(111)

We model electronic properties of the second monolayer Na adatom islands (quantum dots) on the Cu(111) surface covered homogeneously by the first Na monolayer. An axially-symmetric three-dimensional jellium model, taking into account the effects due to the first Na monolayer and the Cu substrate, has been developed. The electronic structure is solved within the local-density approximation of the density-functional theory using a real-space multigrid method. The model enables the study of systems consisting of thousands of Na-atoms. The results for the local density of states are compared with differential conductance ($dI/dV$) spectra and constant current topographs from Scanning Tunneling Microscopy.Comment: 10 pages, 8 figures. For better quality figures, download http://www.fyslab.hut.fi/~tto/cylart1.pd

COPD classification models and mortality prediction capacity

Our aim was to assess the impact of comorbidities on existing COPD prognosis scores. Patients and methods: A total of 543 patients with COPD (FEV1 < 80% and FEV1/ FVC <70%) were included between January 2003 and January 2004. Patients were stable for at least 6 weeks before inclusion and were followed for 5 years without any intervention by the research team. Comorbidities and causes of death were established from medical reports or information from primary care medical records. The GOLD system and the body mass index, obstruction, dyspnea and exercise (BODE) index were used for COPD classification. Patients were also classified into four clusters depending on the respiratory disease and comorbidities. Cluster analysis was performed by combining multiple correspondence analyses and automatic classification. Receiver operating characteristic curves and the area under the curve (AUC) were calculated for each model, and the DeLong test was used to evaluate differences between AUCs. Improvement in prediction ability was analyzed by the DeLong test, category-free net reclassification improvement and the integrated discrimination index. Results: Among the 543 patients enrolled, 521 (96%) were male, with a mean age of 68 years, mean body mass index 28.3 and mean FEV1% 55%. A total of 167 patients died during the study follow-up. Comorbidities were prevalent in our cohort, with a mean Charlson index of 2.4. The most prevalent comorbidities were hypertension, diabetes mellitus and cardiovascular diseases. On comparing the BODE index, GOLDABCD, GOLD2017 and cluster analysis for pre-dicting mortality, cluster system was found to be superior compared with GOLD2017 (0.654 vs 0.722, P=0.006), without significant differences between other classification models. When cardiovascular comorbidities and chronic renal failure were added to the existing scores, their prognostic capacity was statistically superior (P<0.001). Conclusion: Comorbidities should be taken into account in COPD management scores due to their prevalence and impact on mortalit

Condiciones de trabajo y morbilidad entre mineros del carbón en Guachetá, Cundinamarca: la mirada de los legos

Introduction: Investigations in Colombia about work and health conditions in coal mining are scarce and few have focused on the perception of the exposed population and their behaviors in response to inherent risks.Objective: To determine the association between work conditions and the perception of morbidity among coal miners in Guachetá, Cundinamarca.Materials and methods: A cross-sectional study was performed with 154 workers selected randomly from the total registered with the municipality. Information about social and demographic characteristics and work and health conditions in the mines was gathered. The prevalence was estimated for respiratory, musculoskeletal and auditory disorders. The associations between certain work conditions, and events with a prevalence over 30% were explored using bivariate and multivariate analyses with Poisson regressions with robust variance.Results: Workers were mostly men. Ages ranged from 18 to 77 years. Most frequently reported health problems were: back pain (46.1 %), pain in an upper limb (40.3%), pain in a lower limb (34.4 %), and respiratory (17.5 %) and auditory problems (13.6 %). Significant differences in perception were found depending on time on the job and underground or ground work conditions.Conclusions: The most recognized risks were those associated with musculoskeletal disorders since they were closer in time to the work performed (time discount). Some actions to identify psychological traits are proposed in order to improve risk perception among coal miners.Introducción. En Colombia, la investigación sobre las condiciones de trabajo y salud en la minería carbonífera es escasa y no toma en consideración la percepción de la población expuesta y sus comportamientos frente a los riesgos inherentes.Objetivo. Determinar la asociación entre las condiciones de trabajo y la morbilidad percibidas por los trabajadores de minas de carbón en Guachetá, Cundinamarca.Materiales y métodos. Se hizo un estudio transversal con 154 trabajadores seleccionados aleatoriamente del total registrado en la alcaldía municipal. Se indagó sobre las características sociodemográficas, y las condiciones de trabajo y de salud en las minas. Se estimaron las prevalencias de los trastornos respiratorios, osteomusculares y auditivos, y se exploraron las asociaciones entre algunas condiciones de trabajo y los eventos adversos con prevalencia superior al 30 % de forma bivariada y múltiple mediante regresiones de Poisson con varianza sólida.Resultados. Los trabajadores eran, en su mayoría, hombres, con edades entre los 18 y los 77 años. Los problemas de salud más frecuentemente reportados fueron: dolor lumbar (46,1 %), dolor miembros superiores (40,3 %), dolor en miembros inferiores (34,4 %), trastornos respiratorios (17,5 %) y problemas auditivos (13,6 %). Se registraron diferencias importantes en la percepción, dependiendo de la antigüedad laboral y las condiciones de trabajo, subterráneo o de superficie.Conclusión. Los riesgos más reconocidos fueron los relacionados con los trastornos osteomusculares, por ser más cercanos en el tiempo con respecto al trabajo realizado (“descuento temporal”). Se proponen acciones basadas en la identificación de rasgos psicológicos, para mejorar la percepción del riesgo entre los mineros del carbón