Miracle-dz/UniFAR-FTUs huggingface dataset:
Determining Volcanic Deformation at San Miguel Volcano, El Salvador by Integrating Radar Interferometry and Seismic Analyses

From the early 1500’s to the present day, San Miguel volcano has experienced at least 25 small eruptions making it one of the most active volcanoes in the El Salvadoran volcanic chain. From 1867 to present, the volcano experienced at most 15 explosive, central vent eruptions with Volcano Explosivity Indices (VEI) of 1 or 2. To understand the explosive volcanism, we conduct an integrated geophysical study to determine which areas around the volcano are undergoing deformation that could lead volcanic hazards such as slope failure or flank lava flows. We analyze the volcanism by integrating interferometric synthetic aperture radar (InSAR) results with earthquake source location data from a ten-month (March 2007-January 2008) seismic deployment. The InSAR results show a maximum of 6 ± 0.1 cm of volcanic inflation from March 2007 to mid-October 2007. During this time, seismic activity increased to a Realtime Seismic-Amplitude Measurement (RSAM) value of >400. Normal RSAM values for this volcano are <50. A period of quiescence began in mid-October 2007, and a maximum of 4 ± 0.1 cm of deflation was observed in the interferometry results from mid-October to mid-January 2008. Clustering of at least 50 earthquakes that occurred between March 2007 and January 2008 defines a 7 km long, 1.5 km wide, and 1.75 km deep region of volcano-tectonic deformation. This activity is the result of magma and gas movement along the San Miguel Fracture Zone (SMFZ), a north-south fracture that cuts across the summit crater. The earthquakes in this zone were classified into four types, and among them gas movement is indicated by “Tectonic” events
Transport of fluid and electric current through a single fracture

One expects the hydraulic and electrical conductivities of rock to be related, since there is an analogy between the differential equations describing each process. Fractures in rock are commonly described by the parallel plate model, where the fracture surfaces are smooth and parallel with a separation or aperture of /ital d/. For this model the hydraulic conductivity is proportional to /ital d//sup 3/, whereas the electrical conductivity is proportional to /ital d/. Deviations from the parallel plate model are expected, since real fracture surfaces are rough and in partial contact. Computer simulations of fluid flow and conduction of electricity were performed on simulated fractures composed of rough surfaces generated with a fractal algorithm. The finite difference method was used to calculate the volume flow rate and electric current. This solution was used in the parallel plate model to get an effectie hydraulic aperture /ital d//sub h/ and electric aperture /ital d//sub e/. The electric and hydraulic apertures are nearly the same when the surfaces are widely separated. However, /ital d//sub e/ is always smaller than /ital d//sub h/, with the difference increasing as the fracture closes. Additionally, the local directions of fluid flow and electric current are not the same.more » Thus contrary to the common assumption, the actual path length of a fluid particle as measured by the tortuosity is different for each process. The results of these simulations are consistent with the ''equivalent channel model,'' which shows that by introducing the tortuosity of the fluid flow or electric current paths, one can relate the microscopic physics of the transport properties to the macroscopic behaviors described by Darcy's and Ohm's laws. /copyright/ American Geophysical Union 1989« less
X-ray single-crystal structure refinement of an OH-rich topaz from Sulu UHP terrane (Eastern China) - Structural foundation of the correlation between cell parameters and fluorine content

An OH-rich topaz, Al 2 SiO 4 F 1.4 OH 0.6 , occurring in a kyanite quartzite of the Sulu UHP terrane (eastern China) has been optically and chemically (electron microprobe) characterised and its crystal structure refined by single-crystal X-ray diffraction data. Anisotropic refinement converged to R = 0.024 in the Pbnm space group with cell parameters a = 4.6696(8) A, b = 8.8486(17) A, c = 8.3915(22) A. The position of the hydrogen atom has been detected; because the OH → F substitution is less than 50 %, the disorder of H does not lower the overall symmetry. The influence of the OH → F substitution on the lattice parameters is discussed in terms of crystal structure and shown to affect primarily the a and b cell edges; instead c is almost constant. A critical revision of earlier linear correlations of the F content ( w f ) vs the lattice parameters and the availability of new data recently published, allowed to obtain improved regression lines for w f vs a ( r 2 = 0.982) and b ( r 2 = 0.968) cell edges.
An Overlooked Problem in Model Simulations of the Thermohaline Circulation and Heat Transport in the Atlantic Ocean

Abstract Many models of the large-scale thermohaline circulation in the ocean exhibit strong zonally integrated upwelling in the midlatitude North Atlantic that significantly decreases the amount of deep water that is carried from the formation regions in the subpolar North Atlantic toward low latitudes and across the equator. In an analysis of results from the Community Modeling Effort using a suite of models with different horizontal resolution, wind and thermohaline forcing, and mixing parameters, it is shown that the upwelling is always concentrated in the western boundary layer between roughly 30° and 40°N. The vertical transport across 1000 m appears to be controlled by local dynamics and strongly depends on the horizontal resolution and mixing parameters of the model. It is suggested that in models with a realistic deep-water formation rate in the subpolar North Atlantic, the excessive upwelling can be considered as the prime reason for the typically too low meridional overturning rates and northwa.
Resistivity structure of the underconsolidated sediments of the Cascadia Basin

SUMMARY The Cascadia Basin is located on the abyssal plain of the Juan de Fuca Plate, off the west coast of Vancouver Island. The sediments of the Cascadia Basin are very thick, over 2 km, and are underconsolidated because of a high rate of sedimentation. Seismic results suggest that the sediment acoustic velocities are low, and increase slowly and monotonically with depth from the sea-floor. A vertical electric dipole (VED) survey was conducted to obtain the resistivity structure of the upper kilometre of sediments, to determine the physical properties of a thick sequence of abyssal basin sediments, and for comparison with seismic results. While models with multiple layers can be found which fit the data, the‘best-fitting’models share a common feature—decreasing resistivity with depth, which is suggestive of a gradient in the resistivity. The feature is consistent with the results of other geological and geophysical studies. In particular, the seismic results do not indicate any significant contrast in the physical properties, i.e. layering, in the upper 500 m. We extend the VED theory to the case where resistivity varies continuously with depth, and obtain a gradient model that fits the Cascadia Basin data marginally better than simple layered models. The model resistivity is combined with heat-flow measurements for the determination of physical properties versus depth; the physical property models, the porosity, for example, are not consistent with the physical properties derived from seismic survey results. The mismatch is diagnostic of the underconsolidation, and is primarily due to the effects of the high rate of sedimentation on the seismic velocity and on the heat flow, which in turn influence the physical properties.
A rational function approach for estimating mean annual evapotranspiration

Mean annual evapotranspiration from a catchment is determined largely by precipitation and potential evapotranspiration; characteristics of the catchment (e.g., soil, topography, etc.) play only a secondary role. It has been shown that the ratio of mean annual potential evapotranspiration to precipitation (referred as the index of dryness) can be used to estimate mean annual evapotranspiration by using one additional parameter. This study evaluates the effects of climatic and catchment characteristics on the partitioning of mean annual precipitation into evapotranspiration using a rational function approach, which was developed based on phenomenological considerations. Over 470 catchments worldwide with long‐term records of precipitation, potential evapotranspiration, and runoff were considered, and results show that model estimates of mean annual evapotranspiration agree well with observed evapotranspiration taken as the difference between precipitation and runoff. The mean absolute error between modeled and observed evapotranspiration was 54 mm, and the model was able to explain 89% of the variance with a slope of 1.00 through the origin. This indicates that the index of dryness is the most significant variable in determining mean annual evapotranspiration. Results also suggest that forested catchments tend to show higher evapotranspiration than grassed catchments and their evapotranspiration ratio (evapotranspiration divided by precipitation) is most sensitive to changes in catchment characteristics for regions with the index of dryness around 1.0. Additionally, a stepwise regression analysis was performed for over 270 Australian catchments where detailed information of vegetation cover, precipitation characteristics, catchment slopes, and plant available water capacity was available. It is shown that apart from the index of dryness, average storm depth, plant available water capacity, and storm arrival rate are also significant.
COGNITIVE APPRENTICESHIP: MAKING THINKING VISIBLE

IN ANCIENT times, teaching and learning were accomplished through apprenticeship: We taught our children how to speak, grow crops, craft cabinets, or tailor clothes by showing them how and by helping them do it. Apprenticeship was the vehicle for transmitting the knowledge required for expert practice in fields from painting and sculpting to medicine and law. It was the natural way to learn. In modern times, apprenticeship has largely been replaced by formal schooling, except in children's learning of language, in some aspects of graduate education, and in on-the-job training. We propose an alternative model of instruction that is accessible within the framework of the typical American classroom. It is a model of instruction that goes back to apprenticeship but incorporates elements of schooling. We call this model "cognitive apprenticeship" (Collins, Brown, and Newman, 1989).
A Fast and Scalable Implementation Method for Competing Risks Data with the R Package fastcmprsk

Advancements in medical informatics tools and high-throughput biological experimentation make large-scale biomedical data routinely accessible to researchers. Competing risks data are typical in biomedical studies where individuals are at risk to more than one cause (type of event) which can preclude the others from happening. The Fine-Gray model is a popular and well-appreciated model for competing risks data and is currently implemented in a number of statistical software packages. However, current implementations are not computationally scalable for large-scale competing risks data. We have developed an R package, fastcmprsk, that uses a novel forward-backward scan algorithm to significantly reduce the computational complexity for parameter estimation by exploiting the structure of the subject-specific risk sets. Numerical studies compare the speed and scalability of our implementation to current methods for unpenalized and penalized Fine-Gray regression and show impressive gains in computational efficiency.
Impacts de l’utilisation des eaux polluées en agriculture urbaine sur la qualité de la nappe de Dakar (Sénégal)

L’agriculture urbaine de la region de Dakar est un secteur en plein essor. A cause de la salinisation progressive des eaux de la nappe peu profonde (eaux de Ceanes ), des eaux usees brutes sont utilisees pour irriguer les champs. L’objectif de notre etude est d’evaluer la qualite chimique et microbiologique des eaux de la nappe sous-jacentes aux champs irrigues et d’identifier les sources de pollution. Notre travail a ete effectue dans les sites de Pikine et de Patte d’Oie.L’analyse de la qualite chimique des eaux d’arrosage a montre qu’a Pikine, la conductivite des eaux de Ceanes est plus elevee (4822±2411 µS cm-1) par rapport a celle des eaux usees (3579±1242 µS cm-1 ; p<0.04). Par contre a Patte d’Oie, les eaux d’arrosage sont moins salees (<3000 µS cm-1). La quantite d’azote total de tous les types d’eaux d’arrosage est superieure a la valeur guide de l’OMS (5-30 mg l-1). Salmonella spp. a ete isolee dans 35 % des eaux d’arrosage. Un echantillon d’eaux usees a ete positif pour Vibrio cholerae.L’impact des eaux d’irrigation sur la qualite chimique et microbiologique de la nappe d’eau souterraine est fortement influence par la pluviometrie et est different selon le site considere.Ce travail a montre que l’irrigation avec les eaux polluees et l’usage de fumiers organiques peut alterer la qualite de la nappe et constituer des risques pour la sante.
Reconstructing of erythemal ultraviolet radiation levels in Europe for the past 4 decades

[1] This paper is based on a comparative study on ultraviolet radiation (UV) measurements and UV reconstruction models for eight sites in Europe. Reconstruction models include neural network techniques and radiative transfer modeling combined with empirical relationships. The models have been validated against quality-controlled ground-based measurements, 8 to 20 years, on time scales ranging from daily to yearly UV sums. The standard deviations in the ratios of modeled to measured daily sums vary between 10 and 15%. The yearly sums agree within a 5% range. Depending on the availability of ancillary measurements, reconstructions have been carried out to the early 1960s. A method has been set up to educe one best estimate of the historical UV levels that takes into account the long-term stability and underlying agreement of the models, and the agreement with actual UV measurements. Using this best estimate, the yearly sums of erythemally weighted UV irradiance showed a range of 300 kJ/m2 at 67°N to 750 kJ/m2 at 40°N. The year-to-year variability was lowest at 40°N with a relative variation of 4.3%; for central and northern European latitudes this year-to-year variation was 5.2 to 6.5%. With regard to the period 1980 to 2006, first-order trend lines range from 0.3 ± 0.1 to 0.6 ± 0.2% per year, approximately two thirds of which can be attributed to the diminishing of cloudiness and one third to ozone decline.
Rapid Mixing of the Switch Markov Chain for Strongly Stable Degree Sequences and 2-Class Joint Degree Matrices

htmlabstract The switch Markov chain has been extensively studied as the most natural Markov Chain Monte Carlo approach for sampling graphs with prescribed degree sequences. We use comparison arguments with other, less natural but simpler to analyze, Markov chains, to show that the switch chain mixes rapidly in two different settings. We first study the classic problem of uniformly sampling simple undirected, as well as bipartite, graphs with a given degree sequence. We apply an embedding argument, involving a Markov chain defined by Jerrum and Sinclair (TCS, 1990) for sampling graphs that almost have a given degree sequence, to show rapid mixing for degree sequences satisfying strong stability, a notion closely related to P-stability. This results in a much shorter proof that unifies the currently known rapid mixing results of the switch chain and extends them up to sharp characterizations of P-stability. In particular, our work resolves an open problem posed by Greenhill (SODA, 2015). Secondly, in order to illustrate the power of our approach, we study the problem of uniformly sampling graphs for which, in addition to the degree sequence, a joint degree distribution is given. Although the problem was formalized over a decade ago, and despite its practical significance in generating synthetic network topologies, small progress has been made on the random sampling of such graphs. The case of a single degree class reduces to sampling of regular graphs, but beyond this almost nothing is known. We fully resolve the case of two degree classes, by showing that the switch Markov chain is always rapidly mixing. Again, we first analyze an auxiliary chain for strongly stable instances on an augmented state space and then use an embedding argument.
GAS HYDRATES AND THEIR ASSOCIATION WITH MUD DIAPIR/MUD VOLCANOES ON THE LOUISIANA CONTINENTAL SLOPE

Gas hydrates reported in Green Canyon Block 184/185 are associated with an acoustically amorphous mound delineated on high resolution geophysical profiles. This elliptical mound is orientated parallel to prominent fault trends and is connected at depth with a regional chaotic seismic facies. Using this structure as a model, the location of gas hydrates was predicted from geohazard data in Mississippi Canyon Block 798. Structures of similar acoustic character and geologic setting are also found in Ewing Bank Blocks 873 and 874 in water depths too shallow for hydrate formation. The presence of gassy sediments combined with the common elements in the geologic settings as defined by high resolution geophysical profiles indicates that the acoustically amorphous structures are the extrusions of gassy muds from relatively shallow depths. These structures fit into the continuum between the mud diapir and mud volcano classifications. At the seafloor these mud mounds provide the sites for the generation of authigenic carbonates and, when in a deepwater setting, the sites for gas hydrate formation.
A multiple object tracking and detection algorithm using PMHT and FCM

An efficient algorithm based on PMHT and FCM is presented to track and detect the infrared multiple targets from the sequences of IR. Candidate targets can be obtained and saved by preprocessing IR data, and the true target can be detected from the above candidate targets through tracking those targets by PMHT algorithm and prior knowledge. Data association and target detection can be realized by FCM. At the same time, target' disappearing and new targets' emerging phenomena occasionally arise during target tracking. This problem can be solved by 'memorizing and filling'. The proposed approach is validated using actual infrared image sequences. Experiment results indicate high performance of the proposed method.
Multifactorial discriminant analysis of morphological and heat-tolerant traits in indigenous, exotic and cross-bred turkeys in Nigeria

Este estudio examina la capacidad para distinguir los rasgos morfologicos y de tolerancia al calor en pavos autoctonos, exoticos y cruzados en Nigeria mediante el analisis discriminante multivariado. Un total de 228 pavos de 20 semanas de edad fueron utilizados en el estudio. Los parametros corporales medidos fueron el peso corporal (BW), diametro longitudinal (BL), longitud del tarso (SL), longitud del muslo (TL), longitud de quilla (KL), perimetro toracico (BG), temperatura rectal (RT), frecuencia del pulso (PR), frecuencia respiratoria (FR) y el indice de estres termico (HI). El analisis de la varianza revelo que los pavos exoticos mostraban valores significativamente ( p < 0,05) mayores que los pavos autoctonos de Nigeria y que los cruzados para todos los rasgos morfologicos, con la excepcion de la TL. Sin embargo, los pavos autoctonos y los cruzados parecian tener mas capacidad de adaptacion que los exoticos en base a valores de HI mas bajos. El dimorfismo sexual se observo solo en los caracteres morfologicos, donde los machos presentaron de forma significativa ( p < 0,05) un mayor BW, BL, SL, TL y KL que en las hembras. Sin embargo, el analisis discriminante por pasos revelo que BW, TL y HI, fueron las variables mas discriminantes a la hora de separar los tres grupos geneticos. La mayor distancia de Mahalanobis se observo entre los pavos autoctonos y exoticos (36,68), mientras que la distancia mas corta se registro entre los pavos autoctonos y los cruzados (7,97). El diagrama canonico puso de manifiesto la heterogeneidad de las poblaciones de pavo, agrupando las aves por separado. En el nivel de asignacion mas cercano del analisis discriminante, el 100,00%, el 98,73%y el 96,43%de pavos exoticos, cruzados y autoctonos fueron asignados correctamente en sus grupos de origen genetico. Los presentes hallazgos podrian ayudar a la implementacion de una estrategia de conservacion y mejora de los pavos autoctonos hacia el desarrollo sostenible de los recursos zoogeneticos.
Paid employment and common mental disorders in 50–64-year olds: analysis of three cross-sectional nationally representative survey samples in 1993, 2000 and 2007

Aims. Associations between employment status and mental health are well recognised, but evidence is sparse on the relationship between paid employment and mental health in the years running up to statutory retirement ages using robust mental health measures. In addition, there has been no investigation into the stability over time in this relationship: an important consideration if survey findings are used to inform future policy. The aim of this study is to investigate the association between employment status and common mental disorder (CMD) in 50–64-year old residents in England and its stability over time, taking advantage of three national mental health surveys carried out over a 14-year period. Methods. Data were analysed from the British National Surveys of Psychiatric Morbidity of 1993, 2000 and 2007. Paid employment status was the primary exposure of interest and CMD the primary outcome – both ascertained identically in all three surveys (CMD from the revised Clinical Interview Schedule). Multivariable logistic regression models were used. Results. The prevalence of CMD was higher in people not in paid employment across all survey years; however, this association was only present for non-employment related to poor health as an outcome and was not apparent in those citing other reasons for non-employment. Odds ratios for the association between non-employment due to ill health and CMD were 3.05 in 1993, 3.56 in 2000, and 2.80 in 2007, after adjustment for age, gender, marital status, education, social class, housing tenure, financial difficulties, smoking status, recent physical health consultation and activities of daily living impairment. Conclusions. The prevalence of CMD was higher in people not in paid employment for health reasons, but was not associated with non-employment for other reasons. Associations had been relatively stable in strength from 1993 to 2007 in those three cross-sectional nationally representative samples.