Influence of land use and climate on the load of suspended solids in catchments of Andean rivers.

Understanding the interaction between anthropogenic land use and the rainfall pattern can be crucial to predict changes in total suspended solids (TSS) in streams and rivers. We assessed the effects of land use and annual rainfall on the TSS load of 19 southern Chilean catchments. The results indicated that the concentration of TSS increased in catchments with a rainy regime and greater annual precipitation. TSS load also increased as the surface of open areas increased at the catchment scale and decreased with increasing cover of glaciers and perennial snow. However, we did not find support for models with interaction terms between climate and land use. Results suggest that a regional decrease in annual rainfall accompanied by an increase in the altitude of the zero isotherms, as predicted by climate models, should have multiple effects on TSS. In particular, increased TSS load can be expected from a contraction of glaciers and perennial snow areas as well as the intensification of new crops and urban expansion.

Evaluating clinical dermatology practice in medical undergraduates.

The acquisition of competences (the set of knowledge, skills and attitudes required to perform a job to a professional level) is considered a fundamental part of medical training. Dermatology competences should include, in addition to effective clinical interviewing and detailed descriptions of skin lesions, appropriate management (diagnosis, differentiation, and treatment) of common skin disorders and tumors. Such competences can only be acquired during hospital clerkships. As a way of certifying these competences, we propose evaluating the different components as follows: knowledge, via clinical examinations or critical incident discussions; communication and certain instrumental skills, via structured workplace observation and scoring using a set of indicators; and attitudes, via joint evaluation by staff familiar with the student.

An assessment of heavy metal contamination in surface sediment using statistical analysis.

The distribution and accumulation of heavy metals in the sediments, especially those nearest of wastewater discharges of south of Spain, were investigated. Sediment samples from 14 locations were collected and characterised for metal content (e.g. Ni, Cu, Zn, Cr, Pb, Mn, Cd and Hg), organic carbon, total nitrogen, total phosphorous, n-hexane-extractable material, carbonates and grain size. Concentration data were processed using correlation analysis and factor analysis. The correlation analysis of concentrations data showed important positive correlations among organic carbon, total phosphorus, Cu, Zn, Cd and Hg, otherwise weak correlations among Mn, Cr, Ni and CO(3) (2-), indicating that these metals have complicated geochemical behaviours. The use of statistical factor analysis also confirmed these results. Sediments pollution assessment was carried out using geoaccumulation and metal pollution indexes (MPI(8)). The results revealed that sediments of Cádiz bay and Sancti Petri channel were uncontaminated with the studied metals.

Spatial distribution of contaminants in sediments of two rivers crossing Tangier (northern Morocco).

The distribution and accumulation of heavy metals in the sediments of two rivers which cross various agglomerations of Tangier city, Morocco, were investigated. Surficial sediment samples were collected during 2005 and characterized for metal content (Zn, Pb, Cd, Cu, Cr and Ni), organic matter, total nitrogen, and n-hexane extractable material (HEM). The organic components (organic carbon, total nitrogen and HEM) show a slightly increasing enrichment from the upstream to the downstream of the emissary. An evaluation of the heavy metal pollution status of both tributaries was carried out using the metal pollution index (MPI). The results revealed the importance of anthropic pressure and the zones influenced by industrial discharges, which keep the metals Pb, Cr and Ni at high levels. Comparison with international regulatory guidelines for sediments revealed serious contamination of Cr, Zn and Ni.

Modelization of anaerobic processes during co-digestion of slowly biodegradable substrates.

The influence of the soluble substrates over the anaerobic processes has been extensively investigated, but little is known about the effects of particulate substrate. The biodegradation of these substrates starts with the hydrolytic step, this process is slower than the other ones involved in the biodegradation of particulate substrates and usually becomes the rate-limiting step. This study investigate the effect of the initial total solids (TS) concentration on the anaerobic co-digestion of two slowly biodegradable organic substrates. The wastes mixtures were prepared at different dilutions in the range from 10% to 28% TS. From these experiments it was observed that as TS concentration increased, the methane production decreased. These results were modelled and it was observed that neither hydrolysis nor fermentation stages controlled the methane production rate. Being a substrate inhibition event experienced at the methanogenic stage the responsible of the lower methane production when operating at high TS concentrations.

Analysis of methanogenic activity in a thermophilic-dry anaerobic reactor: use of fluorescent in situ hybridization.

Methanogenic activity in a thermophilic-dry anaerobic reactor was determined by comparing the amount of methane generated for each of the organic loading rates with the size of the total and specific methanogenic population, as determined by fluorescent in situ hybridization. A high correlation was evident between the total methanogenic activity and retention time [-0.6988Ln(x)+2.667] (R(2) 0.8866). The total methanogenic activity increased from 0.04x10(-8) mLCH(4) cell(-1)day(-1) to 0.38x10(-8) mLCH(4) cell(-1)day(-1) while the retention time decreased, augmenting the organic loading rates. The specific methanogenic activities of H(2)-utilizing methanogens and acetate-utilizing methanogens increased until they stabilised at 0.64x10(-8) mLCH(4) cell(-1)day(-1) and 0.33x10(-8) mLCH(4) cell(-1)day(-1), respectively. The methanogenic activity of H(2)-utilizing methanogens was higher than acetate-utilizing methanogens, indicating that maintaining a low partial pressure of hydrogen does not inhibit the acetoclastic methanogenesis or the anaerobic process.

Evaluation of metal contamination in sediments from north of Morocco: geochemical and statistical approaches.

Concentrations of Fe, Mn, Cr, Cu, Ni, Pb, Zn, Cd and Hg were evaluated in surface sediments of two rivers from north of Morocco, known as Souani and Mghogha rivers. Significantly higher concentrations in mg kg(-1) dry weight (dw) of Mn (747.6 vs. 392.9), Cr (86.4 vs. 56.3), Zn (299.5 vs. 138.5) were found in sediment samples from Mghogha when compared with Souani river. Average concentrations of Cd and Hg in several sediment samples from both rivers were above the effect range median that predicts toxic effects to aquatic organisms. The calculation of enrichment factors showed that Mn, Cr, Cu and Ni were depleted, whereas Pb and Hg were enriched. The results of geoaccumulation index revealed that sediments of both rivers were unpolluted with most of the metals and moderately contaminated with Fe and Hg. Some of elevated concentrations of Hg, principally in Mghogha River, were due to anthropogenic sources including the direct discharges of industrial zone.

Evolution of microorganisms in thermophilic-dry anaerobic digestion.

Microbial population dynamics were studied during the start-up and stabilization periods in thermophilic-dry anaerobic digestion at lab-scale. The experimental protocol was defined to quantify Eubacteria and Archaea using Fluorescent in situ hybridization (FISH) in a continuously stirred tank reactor (CSTR), without recycling solids. The reactor was subjected to a programme of steady-state operation over a range of the retention times from 40 to 25 days, with an organic loading rate between 4.42 and 7.50 kg volatile solid/m3/day. Changes in microbial concentrations were linked to traditional performance parameters such as biogas production and VS removal. The relations of Eubacteria:Archaea and H2-utilising methanogens:acetate-utilising methanogens were 88:12 and 11:1, respectively, during start-up stage. Hydrogenotrophic methanogens, although important in the initial phase of the reactor start-up, were displaced by acetoclastic methanogens at steady-state, thus their relation were 7:32, respectively. The methane yield coefficient, the methane content in the biogas and VS removal were stabilized around 0.30 LCH4/gCOD, 50% and 80%, respectively. Methanogenic population correlated well with performance measurements.

Modeling and simulation of different and representative engineering problems using Network Simulation Method.

Mathematical models simulating different and representative engineering problem, atomic dry friction, the moving front problems and elastic and solid mechanics are presented in the form of a set of non-linear, coupled or not coupled differential equations. For different parameters values that influence the solution, the problem is numerically solved by the network method, which provides all the variables of the problems. Although the model is extremely sensitive to the above parameters, no assumptions are considered as regards the linearization of the variables. The design of the models, which are run on standard electrical circuit simulation software, is explained in detail. The network model results are compared with common numerical methods or experimental data, published in the scientific literature, to show the reliability of the model.

Thermal analysis in the evaluation of sediment pollution.

Characterization of organic matter in four sediments in the infuence area of wastewater discharges was carried out by both chemical and thermal analysis in order to assess their pollution level. Oxidisable organic carbon and organic matter were calculated by the standard methodology in laboratory. Thermogravimetry (TG), between 50 and 900 degrees C, was simultaneously performed in oxidizing conditions on ground sediments samples after three different pretreatments. Linear regression adjust of thermal analysis results versus chemical parameters provides the better Pearson's coefficients, leading to the best coefficients for weight loss in 250-400 degree C temperature range versus oxidisable organic carbon and organic matter at 360 degrees C, respectively. These results demonstrated the utility of thermoanalysis technique for the evaluation of the organic matter content of fresh sediments.

[Study of the diagnostic agreement on headaches between neurology and primary care]. / Estudio de concordancia diagnostica en cefalea entre neurologia y atencion primaria.

INTRODUCTION: Headache as a symptom is a very common disease and one of the main reasons for consultation in primary care. AIM: To analyze the characteristics of patients referred from primary care to general neurology whose chief complaint was headache and/or neuralgia and diagnostic agreement. PATIENTS AND METHODS: Cross-sectional study of all patients referred from primary care; demographic/clinical variables were collected and diagnostic hypothesis by primary care and general neurology were compared by determining their agreement. RESULTS: 2,514 were referred from primary care patients (588 of them on a preferential basis); in 378 cases the reason for consultation was headache and/or neuralgia (average 42.46 years; 77.8% female). In 139 patients it was established only a semiological diagnostic and other episodic migraine predominated (49.79%), chronic tension headache (18.41%) and trigeminal neuralgia (12.13%). Since general neurology, the most common diagnoses were, respectively, 33.86%, 24.05% and 18.67%. A compatible kappa coefficient of 0.543 (p < 0.05) with a moderate agreement when considering only those patients referred from primary care to a specific diagnosis was obtained. CONCLUSIONS: Headaches are a very common reason for consultation in primary care (15%). The diagnostic agreement is moderate in our health sector so it is necessary to design training programs to help outline the criteria for referral to specialists and improve care for our patients.

TITLE: Estudio de concordancia diagnostica en cefalea entre neurologia y atencion primaria.Introduccion. La cefalea como sintoma es una patologia frecuente y uno de los principales motivos de consulta por parte de atencion primaria. Objetivo. Analizar las caracteristicas de los pacientes derivados desde atencion primaria a la consulta de neurologia general con cefalea o neuralgia como motivo de consulta, y la concordancia diagnostica. Pacientes y metodos. Estudio descriptivo transversal de todos los pacientes remitidos desde atencion primaria; se recogieron variables demograficas/clinicas y se compararon las hipotesis diagnosticas de atencion primaria y neurologia, determinando su concordancia. Resultados. Se remitieron desde atencion primaria 2.514 pacientes (588 de ellos con caracter preferente); en 378 casos el motivo de la consulta fue cefalea o neuralgia (42,46 años de media; el 77,8%, mujeres). En 139 pacientes se establecio tan solo un diagnostico semiologico y en el resto predominaron la migraña episodica (49,79%), la cefalea tensional cronica (18,41%) y la neuralgia del trigemino (12,13%). Desde neurologia, los diagnosticos mas frecuentes fueron, respectivamente, 33,86%, 24,05% y 18,67%. Se obtuvo un coeficiente kappa de 0,543 (p < 0,05), compatible con una concordancia moderada al considerar solo los pacientes remitidos desde atencion primaria con un diagnostico concreto. Conclusiones. Las cefaleas constituyen un motivo de consulta desde atencion primaria muy frecuente (15%). La concordancia diagnostica es moderada en nuestro sector sanitario, por lo que es necesario diseñar programas de formacion que ayuden a perfilar los criterios de derivacion al especialista y mejorar la atencion a nuestros pacientes.

[Spontaneous tumor lysis syndrome in a patient with non-Hodgkin's lymphoma]. / Síndrome de lisis tumoral espontáneo en una paciente con linfoma no Hodgkin.

An 77-year-old woman with no previous history of malignancy was admitted to the hospital with generalized weakness and malaise. Physical examination demonstrate multiple cervical adenopathies. The day after admission the patient developed severe metabolic derangements (hyperuricemia, hypocalcemia, hyperkalemia, hyperphosphatemia and azotemia) and expired. Consent for necropsy was refused. The cytology and molecular studies of cervical adenopathy sample were diagnostic of high-grade non-Hodgkin's lymphoma. A presumptive diagnosis of non Hodgkin lymphoma with spontaneous tumor lysis syndrome was made.

Analysis of HFE-codon 63/282 (H63D/C282Y) gene variants in mexican mestizos. Blood donors and patients with hereditary hemochromatosis.

BACKGROUND: The prevalence of hereditary hemochromatosis (HH) (H63D/C282Y) gene variants in Mexico is unknown. METHODS: Using amplification refractory mutation system polymerase chain reaction, an analysis of HFE-codon 63/282 (H63D/C282Y) gene variants was performed in a group of 153 Mexican mestizo blood donors and six individuals with familial iron overload. RESULTS: In normal blood donors, three heterozygotes for the C282Y mutation (2.0%) were found, whereas 18 heterozygotes and one homozygote for the H63D mutation (11.8% and 0.6%, respectively) were identified; there was one compound heterozygote for the C282Y/H63D mutation. These data resulted in allele frequencies of 0.013 (+/-0. 2%, alpha = 0.05) and 0.062 (+/-0.9%, alpha = 0.05), respectively, for these two mutations, results similar to those found in whites. In the six patients with the HH phenotype, two were found to be heterozygous for C282Y and one heterozygous for H63D; three individuals with HH had no gene mutations. Two heterozygous HH individuals were found to have iron overload associated with other conditions: one heterozygous for C282Y infected with HIV, and another heterozygous for H63D with heterozygous beta-thalassemia. CONCLUSIONS: The prevalence of C282Y and H63D HFE gene mutations in Mexican mestizos is similar to that found in other populations. In addition, other gene mutations responsible for HH in the Mexican mestizo population should be investigated, because, in three of six individuals with the HH phenotype, neither of the two mutations was recorded.

Kinematic characteristics of Andalusian, Arabian and Anglo-Arabian horses: a comparative study.

The aim of this study was to compare the kinematic trot characteristics of three different breeds of horse: Andalusian (AN, n = 15), Arabian (AR, n = 7) and Anglo-Arabian (AA, n = 5) using standard computer-assisted videography (25 Hz). Linear, temporal and angular parameters in fore- and hind limbs were analysed in six randomly selected strides per horse. Normalised angle-time diagrams along the complete stride were obtained for all joints angles in each breed and specific kinematic characteristics were detected graphically. AA horses displayed longer swing durations in both limbs ans a shorter angular range of motion (ARM) in scapula and pelvis inclination and in shoulder, hip and forelimb retraction-protraction angles. At lift off, stifle and tarsal joint angles were more flexed. In general, only small differences were observed in AR horse kinematics when compared with the other 2 breeds. AN horses presented negative overtracking length, which was positive in AR and AA. In AN horses the elbow and carpal joints were more flexed at the moment of maximal elevation, elbow and fore-fetlock joints also exhibited a larger ARM due to a smaller angle at maximal flexion. In the hind limbs, tarsal, hind fetlock and retraction-protraction angles presented a larger ARM in AN horses due to greater maximal flexion in the tarsal and hind fetlock joints. Fore- and hind fetlocks were also more flexed in horses from this breed. In conclusion, differences between kinematic variables at the trot were observed in the three breeds studied here, mainly in forelimb joints. The most outstanding feature was the greater forelimb flexion recorded in AN horses than in the other breeds which is consistent with the elevated movements in this breed. In AA horses, the ARM of proximal joints involved in retraction protraction in both fore- and hind limbs was smaller. All the differences observed highlighted the idiosyncratic nature of the trot in each breed; this may influence the functional capacity of each breed.

Angular kinematic patterns of limbs in elite and riding horses at trot.

Normal speed videography was used to determine the angular parameters of 28 Spanish Thoroughbreds at trot. Horses were divided into 3 groups: Group UT, comprising 9 animals (provided by the VII National Stud, Cordoba, Spain) which had undergone no specific training programme and which were hand led at the trot; Group T, formed by 19 horses considered to be highly bred and trained, and which were also hand led; and Group RT, comprising the same horses as the latter group but this time trotted by a rider. Each animal was filmed 6 times from the right-hand side, using a Hi8 (25 Hz) video camera. Angular parameters for fore- and hindlimb joints were measured in each stride from computer-grabbed frames and entered into a spreadsheet for calculation; parameters included maximum and minimum angles, range of motion, and angles at landing, lift off and maximum hoof height; the times at which maximum angle, minimum angle, lift off and maximum hoof height occurred were calculated as percentages of total stride duration. Stride velocity (mean [s.d.]) was 4.01 (0.62), 3.60 (0.34) and 3.07 (0.36) m/s for Groups UT, T and RT, respectively. Data were then compared between Groups UT-T and Groups T-RT. Compared with Group UT, horses from Group T featured a shorter stance percentage (P<0.001) in both fore- and hindlimbs. The range of motion in forelimbs was smaller (P<0.05), due to lower retraction (P<0.001); moreover, maximum retraction appeared earlier (P<0.05). Greater scapular inclination was in evidence (P<0.05) and the shoulder joint extended further (P<0.05). Fore- and hind fetlock joints revealed a relatively shorter hyperextension period during the stance phase (P<0.01). Compared with Group T, horses from Group RT had a longer stance percentage, with belated maximum retraction of the fore- and hindlimbs. The range of movement in scapular inclination was greater (P<0.05), due to a smaller minimum angle (P<0.01), and the shoulder joint flexed more (P<0.05). The elbow joint extended more and for longer during the stance phase. Initial extension of the hip joint (P<0.05) and tarsus (P<0.001) lasted longer. The carpal and fore and hind fetlock joints recorded relatively longer hyperextension times, in addition to greater hyperextension during the stance phase. The results from the present study suggest that rider-effect must be taken in consideration when well gaited horses are selected for dressage purposes.

Changes in cross-sectional area and capillary supply of the muscle fiber population in equine gluteus medius muscle as a function of sampling depth.

The right and left gluteus medius muscles of 4 mature Andalusian stallions were examined by repeated needle biopsy over a specific area and depth, as well as at different depths, to determine whether the cross-sectional area and capillary supply of the various fiber types are homogeneous throughout the muscle. The muscle biopsy specimens were histochemically analyzed for fiber types (myofibrillar adenosine triphosphatase) and capillaries (amylase-periodic acid-Schiff method). Differences between contralateral sites were not identifiable for any of the analyzed variables. Differences between sampling depths were larger than those between sample sites. The percentage of type-1 fibers increased, and that of type-2B fibers decreased as a function of increased sampling depth, but the relative frequency of type-2A fibers did not change with depth. The mean cross-sectional area of type-1 and type-2A fibers increased significantly, and that of type-2B fibers decreased between the most superficial and the deepest sampling sites. The capillary density and the mean number of capillaries per fiber increased as a function of sampling depth, but significant changes were not recorded between sampling depths for overall mean fiber area. The mean number of capillaries in contact with fibers of each histochemical type increased significantly with increasing sampling depth only for type-1 fibers. However, the number of capillaries in contact with fibers changed significantly, relative to the fiber area, as a function of sampling depth; for type-2B fibers this variable increased, whereas for type-2A and type-1 fibers, it decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of operational conditions on biofilm specific activity of an anaerobic fluidized bed reactor.

A key parameter in water and wastewater treatment technology is the biomass activity in terms of substrate removal ability. The effects of organic load rate and percentage of bed expansion on biofilm specific methanogenic activity were determined in an anaerobic fluidized bed reactor treating wine-distillery wastes in the thermophilic range (55 degrees C). The proposed activity tests are highly reproducible: an experiment with three identical tests has shown that the standard deviation with respect to the mean values is less than 3%. Specific tests are applied to measure the maximum methanogenic activities of the biomass carrier in lab-scale anaerobic biofilm reactors. These tests have been successfully applied for monitoring the support colonization process and the evolution of biofilm activity in reactors, anaerobic filter and fluidized bed, with different operating conditions. The results show a dependence between the percentage of bed expansion and the specific activity of methanogenic microbiote on biofilm. There is a relationship between the percentage of bed expansion, the sheer stress on the biofilm and the hydrodynamic conditions in the system. Initial biofilm detachment can be compensated with the increase of biomass and of its activity due to the reduction of the substrate diffusional limitations to the microorganism growth inside the support pores.

Portable pilot plant for evaluating marine biofouling growth and control in heat exchangers-condensers.

Biofouling frequently involves a serious impediment to achieving optimum operating conditions in heat exchangers-condensers. The economic coat and energy losses associated with this phenomenon are significant and the environmental impact of biocides must satisfy stringent regulations. A portable pilot plant has been designed in order to carry out in-situ experimental study as biofilm is formed under thermal and hydrodynamically controlled conditions. The pilot plant has an automatic monitoring, control and data acquisition system, which automatically processes data from indirect measure of fouling in terms of increased fluid frictional and heat transfer resistances. A particular method is used and proposed for direct measuring and biofilm characterization. Once we know the actual film thickness, we can calculate the effective thermal conductivity of the layer by using the appropriate heat transfer equations.

Acute pancreatitis in childhood.

AIM: to evaluate etiological agents involved in acute pancreatitis in children, as well as clinical, laboratory and radiological findings and the illness clinical course. PATIENTS AND METHODS: we reviewed the cases of acute pancreatitis diagnosed over the last 15 years. The criteria used for cases to be included were acute abdominal pain, elevated serum amylase levels and/or ultrasound abnormalities in the pancreatic area in conscious patients, and the last two criteria in unconscious patients. RESULTS: thirty-one children were included (average age 7.9 years, range 2-15; 55% males). Infection and gallstones were the most common causes (19 and 16 %, respectively). In all, 9.7% of cases were drug-related (valproic acid, L-asparaginase, azathioprine combined with high doses of methylprednisolone); 6.5% were traumatic in origin and another 6.5% was due to systemic diseases. In 35.5 % no cause was found (idiopathic). The most frequent symptoms were abdominal pain (90%) and emesis (38%). Amylase serum levels were elevated in all patients. Abdominal ultrasound scans were abnormal in 64%, with an increase in the pancreatic area in 48% and hypoechogenicity in 51%. Seven cases required surgical treatment (22%). Seven children had acute pancreatitis, and three of them died as a result of shock unrelated to pancreatitis. Relapse of disease occurred in 19% of patients. CONCLUSIONS: acute pancreatitis should always be considered in children with abdominal pain. There are a wide variety of etiological factors and in a high percentage of patients no underlying cause is found. Prognosis is variable owing to the heterogeneity of the clinical course of this illness in children.

The influence of speed and height at the withers on the kinematics of sound horses at the hand-led trot.

The influence of speed and height at the withers on some biokinematic stride parameters (linear, temporal and angular) was measured in 15 Spanish Thoroughbreds (Andalusian Purebred) trotted hand-led along a track; analysis was made of the correlation between speed and height at the withers and of some biokinematic parameters of equine locomotion. Both height at the withers and speed were positively and significantly correlated to the linear parameters examined. Temporal parameters did not reveal a significant correlation with the height at the withers. The correlations with the angular parameters were variable, often being significant for both height at withers and speed, although in most cases the coefficient was relatively low, probably owing to the narrow ranges of speed and height at the withers and their low variability. It was concluded that horses at the hand-led trot tend to have low variability in speed during successive trials, although the speed at which they move does have a significant influence on both linear and temporal stride parameters, and also on several angular parameters, while height at the withers has a major effect on linear parameters but less on angular parameters, and does not affect the temporal parameters.