228 research outputs found
Spatial distributions of local illumination color in natural scenes
In natural complex environments, the elevation of the sun and the presence of occluding objects and mutual reflections cause variations in the spectral composition of the local illumination across time and location. Unlike the changes in time and their consequences for color appearance and constancy, the spatial variations of local illumination color in natural scenes have received relatively little attention. The aim of the present work was to characterize these spatial variations by spectral imaging. Hyperspectral radiance images were obtained from 30 rural and urban scenes in which neutral probe spheres were embedded. The spectra of the local illumination at 17 sample points on each sphere in each scene were extracted and a total of 1904 chromaticity coordinates and correlated color temperatures (CCTs) derived. Maximum differences in chromaticities over spheres and over scenes were similar. When data were pooled over scenes, CCTs ranged from 3000 K to 20,000 K, a variation of the same order of magnitude as that occurring over the day. Any mechanisms that underlie stable surface color perception in natural scenes need to accommodate these large spatial variations in local illumination color.This work was supported by the Centro de Física of Minho University, Braga, Portugal, by the European Regional Development Fund through Program COMPETE (FCOMP-01-0124-FEDER-009858/029564), by the National Portuguese funds through Fundação para a Ciência e a Tecnologia, Portugal (Grants PTDC/EEA-EEL/098572/2008 and PTDC/MHC-PCN/4731/2012), and by the Engineering and Physical Sciences Research Council, United Kingdom (Grants GR/R39412/01, EP/B000257/1 and EP/E056512/1). We thank Paulo D. A. Pinto and João M. M. Linhares for collaboration
in the acquisition of hyperspectral data of some scenes and Paulo
D. A. Pinto for the preparation of the gray spheres
Determination of chlorine via the CaCl molecule by high-resolution continuum source graphite furnace molecular absorption spectrometry and direct solid sample analysis
This work investigates the possibilities of high-resolution continuum source graphite furnace molecular absorption spectrometry for the direct determination of Cl in solid samples via the CaCl molecule and measurement of its molecular absorption. The method proposed is based on addition of 400 µg Ca as molecule-forming reagent and of 20 µg Pd as chemical modifier, which helps to stabilize the analyte and enhances sensitivity. The molecular spectrum for CaCl offers different lines with different limits of detection and linear ranges, which permitted to analyze solid samples with different Cl contents. The lowest limit of detection (0.75 ng Cl, corresponding to 0.75 µg g-1 for a typical sample mass of 1 mg) could be achieved by combination of three of the most sensitive lines in the vicinity of 620.862 nm, while the amplest linear range (up to 860 ng Cl) was achieved by selection of the less sensitive line at 377.501 nm. The method developed enabled the direct determination of Cl in solid samples using simple external calibration with aqueous standards. Good precision (5–9% RSD) and accuracy was attained in a series of certified samples of very different nature (i.e. coal, iron oxide, polyethylene, human hair, pine needles, rice flour and milk) and with very different Cl contents, ranging from about 50 µg g-1 to 1% (w/w) Cl. The method appears as particularly useful for Cl determination in samples with elevated Ca contents, for which biased results with other diatomic molecules, such as AlCl or SrCl, may be obtained
Passive interferometric interrogation of a magnetic field sensor using an erbium doped fiber optic laser with magnetostrictive transducer
An erbium doped (Er3+) fiber optic laser is proposed for magnetic field measurement. A pair of FBGsglued onto a magnetostrictive material (Terfenol-D rod) modulates the laser wavelength operation whensubject to a static or a time dependent magnetic field. A passive interferometer is employed to measure thelaser wavelength changes due to the applied magnetic field. A data acquisition hardware and a LabVIEWsoftware measure three phase-shifted signals at the output coupler of the interferometer and processthem using two distinct demodulation algorithms. Results show that sensitivity to varying magneticfields can be tuned by introducing a biasing magnetic field. A maximum error of 0.79% was found, formagnetic fields higher than 2.26 mT-RMS
Melatonin activates endoplasmic reticulum stress and apoptosis in rats with diethylnitrosamine-induced hepatocarcinogenesis
Abstract Hepatocellular carcinoma (HCC) is one of the most lethal human cancers worldwide because of its high incidence, its metastatic potential and the low efficacy of conventional treatment. Inactivation of apoptosis is implicated in tumour progression and chemotherapy resistance, and has been linked to the presence of endoplasmic reticulum stress. Melatonin, the main product of the pineal gland, exerts anti-proliferative, pro-apoptotic and antiangiogenic effects in HCC cells, but these effects still need to be confirmed in animal models. Male Wistar rats in treatment groups received diethylnitrosamine (DEN) 50 mg/kg intraperitoneally twice/once a week for 18 weeks. Melatonin was given in drinking water at 1 mg/ kg/d, beginning 5 or 12 weeks after the start of DEN administration. Melatonin improved survival rates and successfully attenuated liver injury, as shown by histopathology, decreased levels of serum transaminases and reduced expression of placental glutathione S-transferase. Furthermore, melatonin treatment resulted in a significant increase of caspase 3, 8 and 9 activities, polyadenosine diphosphate (ADP) ribose polymerase (PARP) cleavage, and Bcl-associated X protein (Bax)/Bcl-2 ratio. Cytochrome c, p53 and Fas-L protein concentration were also significantly enhanced by melatonin. Melatonin induced an increased expression of activating transcription factor 6 (ATF6), C/EBP-homologous protein (CHOP) and immunoglobulin heavy chain-binding protein (BiP), while cyclooxygenase (COX)-2 expression decreased. Data obtained suggest that induction of apoptosis and ER stress contribute to the beneficial effects of melatonin in rats with DEN-induced HCC
Chronic inflammatory demyelinating polyneuropathy associated with contactin-1 antibodies in a child
A previously healthy 2-year and 9-month old boy was brought to the emergency department for a 6-day history of weakness in the legs and frequent falls, rendering him unable to walk 1 day before admission. He did not have pain, dysphagia, bladder dysfunction, or sensory symptoms. There was no history of trauma, but he developed diarrhea 3 days before symptom onset. Family history was negative for consanguinity or neurologic diseases. At examination, he had bilateral leg weakness requiring substantial aid to walk a few steps and was unable to stand up from the floor. He had absent tendon reflexes in the lower extremities and flexor plantar responses. Strength and reflexes in upper extremities and the rest of the examination were normal. CSF showed a protein concentration of 125 mg/dL (NR: 15-45), with normal white blood cell count and glucose concentration
Ergonomic assessment of postal workers´ pain symptoms and musculoskeletal risks related to parcel processing activity for delivery
The parcel delivery activity is carried out all over the world and workers in this sector have suffered from musculoskeletal disorders (MSDs) due to the strong demand for work generated by the recent increase in e-commerce.
This study aimed to evaluate postal workers' pain symptoms, movements and identify MSDs risks related to the
parcel processing activity for delivery, proposing preventive measures. A sample of thirty-two workers was evaluated with the application of sociodemographic and Nordic questionnaires and electrical bioimpedance. The motion capture sensors were used to evaluate right/left shoulder joints, segment C7-T1 (Cervical) and segment L5-
S1 (Lumbar) of three postal workers (percentiles of anthropometric data: 5, 50, and 95) during four real work
activities that are part of the parcel processing. The analyzed workers presented musculoskeletal complaints in
practically all body regions, with a greater prevalence in shoulders, hands, lower back, and knees. According to
the Body Mass Index (BMI), they were on average overweight (27.8 ± 3.7 kg/m2
). In the movement analysis, we
identified risks related to cervical protrusion, anterior trunk flexion, and shoulder flexion, in addition to repetitive
movements. In some activities, the higher stature showed an increase in lumbar and cervical anterior flexion. The
set of evaluations showed that the activity of processing orders for delivery offers musculoskeletal risks. We identify that ergonomic adaptations are necessary to adapt the heights of the work environment to the statures of the
postal workers. Relevance to industry: The activity of processing orders for delivery is carried out practically all
over the world generating jobs and income for its employees. Nonetheless, there are still situations of ergonomic
disadvantage that can generate musculoskeletal risks. The findings elucidate ergonomic risks and provide useful
information for future ergonomic interventions in the postal/delivery workplace environment.ECT -Eaga Charitable Trust(undefined
Late Holocene woods remains from alluvial/colluvial deposits in the Caldera de Taburiente National Park (La Palma, Canary Islands)
The geomorphological dynamics of the Barranco de Taburiente gorge, in La Palma (Canary Islands), has exposed sub-fossil organic layers in its riverbanks and margins, in which a large number of woody remains have been recovered. Samples have been located along ~3 km of the river and are clustered in three sites. Radiocarbon dating of the remains indicates that the recovered samples date from the late Holocene and have been identified as Pinus canariensis, a pine species that may have long been dominant and stable in the landscapes of the Caldera. The deposition of the remains could be explained by a single geomorphic event related to a humid (and probably torrential) episode. The factors that would explain the persistence of these pinewoods are discussed
Perspectivas para la utilización de la biomasa de cianobacterias fijadoras de nitrógeno como fertilizante orgánico y acondicionador de suelos
Introducción y Objetivos:El incremento de la población mundial genera una demanda creciente de alimentos, y para cubrir esta demanda, la utilización de mayores cantidades de fertilizantes, especialmente nitrogenados, ha sido una de las estrategias más utilizadas para incrementar los rendimientos de las cosechas. No obstante, el manejo inapropiado implica consecuencias perjudiciales para el medio ambiente y la salud humana. Promover la fijación biológica del nitrógeno (FBN) puede significar un aporte reduciendo la dependencia de fertilizantes nitrogenados, sin embargo, este proceso sólo podría cubrir una parte de la demanda requerida en la agricultura intensiva. La obtención de biomasa a partir de microorganismos que realicen la FBN para su utilización como biofertilizantes, es una alternativa promisoria especialmente si se puede acoplar al reciclado y mejoramiento de desechos agroindustriales. En este estudio se propone producir un biofertilizante orgánico y acondicionador de suelos, utilizando la biomasa de una cianobacteria fijadora de nitrógeno, obtenida a partir del reciclado y mejorado de la composición nutricional de un desecho agroindustrial.Materiales y Métodos:La cianobacteria fijadora de nitrógeno Nostoc sp. M2 se cultivó a partir de la vinasa residual de la fermentación alcohólica de un sacarificado de biomasa algal. Las deficiencias en nitrógeno y fósforo en la vinasa pudieron ser suplementadas mediante la FBN y el agregado de harina de hueso respectivamente. La biomasa obtenida fue desecada y molida para su análisis como fertilizante de plantas de interés agronómico en suelos con diferentes contenidos de materia orgánica y diferentes regímenes hídricos. Además, se evaluó la persistencia de nutrientes y capacidad de retención de agua.Resultados:El cultivo de Nostoc a partir de la vinasa alcanzó rendimientos similares a los obtenidos en medios de cultivo de referencia, y permitió la liberación de una considerable cantidad de expolisacáridos en el medio (superiores al 20% de la biomasa celular). La biomasa pudo sustituir la urea como fertilizante en suelos con bajo contenido de nutrientes, sosteniendo el crecimiento de plantas de trigo, maíz y poroto, especialmente en condiciones de riego esporádico. Adicionalmente, se comprobó que la liberación de nitrógeno de la biomasa es más lenta que la urea, mejorando el aprovechamiento del mismo. La aplicación de la biomasa en suelos proporciona una mayor capacidad de retención de agua, previniendo el marchitamiento en plantas de trigo y permitiendo que puedan soportar periodos de estrés hídrico en sequía.Conclusiones:Este estudio apoya la conveniencia de la producción de biomasa como biofertilizante de plantas y acondicionador de suelos, mejorando las condiciones del mismo especialmente en suelos pobres en materia orgánica y/o expuestos a condiciones de desecación o regímenes de precipitaciones semiáridas. A su vez, propone un procedimiento para reciclar y revalorizar desechos agroindustriales acoplándolo a plataformas de producción de microalgas y cianobacterias.Fil: Do Nascimento, Mauro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; ArgentinaFil: Battaglia, Marina Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; ArgentinaFil: Sánchez Rizza, Lara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; ArgentinaFil: Ambrosio, Rafael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; ArgentinaFil: Arruebarrena Di Palma, Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; ArgentinaFil: Curatti, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; ArgentinaXIV Congreso Argentino de Microbiología General (SAMIGE) y XV Congreso Argentino de Microbiología (CAM)Ciudad Autónoma de Buenos AiresArgentinaSociedad Argentina de Microbiología GeneralAsociación Argentina de Microbiologí
Differences In Adipose Tissue And Lean Mass Distribution In Patients With Collagen Vi Related Myopathies Are Associated With Disease Severity And Physical Ability
Mutations in human collagen VI genes cause a spectrum of musculoskeletal conditions in children and adults collectively termed collagen VI-related myopathies (COL6-RM) characterized by a varying degree of muscle weakness and joint contractures and which include Ullrich Congenital Muscular Dystrophy (UCMD) and Bethlem Myopathy (BM). Given that collagen VI is one of the most abundant extracellular matrix proteins in adipose tissue and its emerging role in energy metabolism we hypothesized that collagen VI deficiency might be associated with alterations in adipose tissue distribution and adipokines serum profile. We analyzed body composition by means of dual-energy X-ray absorptiometry in 30 pediatric and adult COL6-RM myopathy patients representing a range of severities (UCMD, intermediate-COL6-RM, and BM). We found a distinctive pattern of regional adipose tissue accumulation which was more evident in children at the most severe end of the spectrum. In particular, the accumulation of fat in the android region was a distinguishing feature of UCMD patients. In parallel, there was a decrease in lean mass compatible with a state of sarcopenia, particularly in ambulant children with an intermediate phenotype. All children and adult patients that were sarcopenic were also obese. These changes were significantly more pronounced in children with collagen VI deficiency than in children with Duchenne Muscular Dystrophy of the same ambulatory status. High molecular weight adiponectin and leptin were significantly increased in sera from children in the intermediate and BM group. Correlation analysis showed that the parameters of fat mass were negatively associated with motor function according to several validated outcome measures. In contrast, lean mass parameters correlated positively with physical performance and quality of life. Leptin and adiponectin circulating levels correlated positively with fat mass parameters and negatively with lean mass and thus may be relevant to the disease pathogenesis and as circulating markers. Taken together our results indicate that COL6-RM are characterized by specific changes in total fat mass and distribution which associate with disease severity, motor function, and quality of life and which are clinically meaningful and thus should be taken into consideration in the management of these patients
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