4,915 research outputs found
Lifestyle Influence on the Content of Copper, Zinc and Rubidium in Wild Mushrooms
The concentration of 18 trace elements in several species of fungi (arranged in three groups: ectomycorrhizae, saprobes, and epiphytes) has been determined. The measurements were made using the methodology of X-ray fluorescence. Higher contents of Cu and Rb (with statistical support) have been found in the ectomycorrhizal species. The Zn content reached higher concentrations in the saprophytic species. According to the normality test and the search for outliers, the species Clitocybe maxima and Suillus bellini accumulate large amounts of Cu and Rb, respectively, so that both can be named as “outliers.” The leftwards displacement of the density curves and their nonnormality are attributed to the presence of these two species, which exhibit hyperaccumulation skills for Cu and Rb, respectively. Regarding Zn absorption, no particular species were classified as outlier; therefore it can be assumed that the observed differences between the different groups of fungi are due to differences in their nutritional physiology
RF plasma cleaning of optical surfaces: A study of cleaning rates on different carbon allotropes as a function of RF powers and distances
An extended study on an advanced method for the cleaning of carbon
contaminations on large optical surfaces using a remote inductively coupled low
pressure RF plasma source (GV10x downstream asher) is reported in this work.
Technical as well as scientific features of this scaled up cleaning process are
analyzed, such as the cleaning efficiency for different carbon allotropes
(amorphous and diamond-like carbon) as a function of feedstock gas composition,
RF power (ranging from 30 to 300W), and source-object distances (415 to 840
mm). The underlying physical phenomena for these functional dependences are
discussed.Comment: 16 pages, 9 figure
Quasi-Biennial variations in helioseismic frequencies: Can the source of the variation be localized?
We investigate the spherical harmonic degree (l) dependence of the "seismic"
quasi-biennial oscillation (QBO) observed in low-degree solar p-mode
frequencies, using Sun-as-a-star Birmingham Solar Oscillations Network (BiSON)
data. The amplitude of the seismic QBO is modulated by the 11-yr solar cycle,
with the amplitude of the signal being largest at solar maximum. The amplitude
of the signal is noticeably larger for the l=2 and 3 modes than for the l=0 and
1 modes. The seismic QBO shows some frequency dependence but this dependence is
not as strong as observed in the 11-yr solar cycle. These results are
consistent with the seismic QBO having its origins in shallow layers of the
interior (one possibility being the bottom of the shear layer extending 5per
cent below the solar surface). Under this scenario the magnetic flux
responsible for the seismic QBO is brought to the surface (where its influence
on the p modes is stronger) by buoyant flux from the 11-yr cycle, the strong
component of which is observed at predominantly low-latitudes. As the l=2 and 3
modes are much more sensitive to equatorial latitudes than the l=0 and 1 modes
the influence of the 11-yr cycle on the seismic QBO is more visible in l=2 and
3 mode frequencies. Our results imply that close to solar maximum the main
influence of the seismic QBO occurs at low latitudes (<45 degrees), which is
where the strong component of the 11-yr solar cycle resides. To isolate the
latitudinal dependence of the seismic QBO from the 11-yr solar cycle we must
consider epochs when the 11-yr solar cycle is weak. However, away from solar
maximum, the amplitude of the seismic QBO is weak making the latitudinal
dependence hard to constrain.Comment: 10 pages, 6 figures, accepted for publication in MNRA
Diamond Color Centers in Diamonds for Chemical and Biochemical Analysis and Visualization
Beyond the sparkle, other properties of diamond havegained increasing attention in the past few decades amongchemists and physicists. Color centers-impurities formed byone or a few foreign atoms or vacancies in the diamondlattice-are one reason for this. While pure diamond istransparent, the presence of color centers causes changes incoloration. Color centers introduce additional electronic statesin the wide band gap of diamond, giving rise to transitions thatabsorb and emit light in the visible spectrum
Prevalence of Cryptosporidium oocysts and Giardia cysts in raw and treated sewage sludges
Treated sludge from wastewater treatment plants (WWTPs) is commonly used in agriculture as fertilizers and to amend soils. The most significant health hazard for sewage sludge relates to the wide range of pathogenic microorganisms such as protozoa parasites.The objective of this study was to collect quantitative data on Cryptosporidium oocysts and Giardia cysts in the treated sludge in wastewater treatment facilities in Spain. Sludge from five WWTPs with different stabilization processes has been analysed for the presence of Cryptosporidium and Giardia in the raw sludge and after the sludge treatment. A composting plant (CP) has also been assessed. After a sedimentation step, sludge samples were processed and (oo)cysts were isolated by immunomagnetic separation (IMS) and detected by immunofluorescence assay (IFA). Results obtained in this study showed that Cryptosporidium oocysts and Giardia cysts were present in 26 of the 30 samples (86.6%) of raw sludge samples. In treated sludge samples, (oo)cysts have been observed in all WWTP's analysed (25 samples) with different stabilization treatment (83.3%). Only in samples from the CP no (oo)cysts were detected. This study provides evidence that (oo)cysts are present in sewage sludge-end products from wastewater treatment processes with the negative consequences for public health.We appreciate the financial support provided by Entidad Publica Saneamiento Aguas (EPSAR).Amoros Muñoz, I.; Moreno Trigos, MY.; Reyes-Sosa, MB.; Moreno-Mesonero, L.; Alonso Molina, JL. (2016). Prevalence of Cryptosporidium oocysts and Giardia cysts in raw and treated sewage sludges. Environmental Technology. 37(22):2898-2904. doi:10.1080/09593330.2016.1168486S28982904372
Calibration of Hydrus-3D model for drip irrigation on stratified soil for intensive agriculture (sand covered soil)
[EN] The development of the wet bulb under drip irrigation in sand covered soils presents a different behavior from that observed under homogeneous soils. The presence of a very active crop also imposes a series of variations that have not been fully characterized. The aim of this work is to present the data acquisition methodology and the necessary precautions to obtain a model that accurately defines the evolution of moisture in wet bulbs generated in sanded soils characteristic of intensive horticultural crops. The procedure for collecting and processing moisture data in stratified soils has been defined. The soil and permeability curve has been adjusted experimentally for each material. It has been proved that the Hydrus-3D model can reproduce the behavior of a sand covered soils and it has been possible to verify that the predictions are adequate to what has been observed in the field.[ES] El desarrollo del bulbo mojado bajo riego localizado en suelos enarenados presenta un comportamiento diferente del observado bajo suelos homogĂ©neos. La presencia de un cultivo muy activo, tambiĂ©n impone una serie de variaciones que no han sido plenamente caracterizadas. El objetivo de este trabajo es presentar la metodologĂa de adquisiciĂłn de datos y las precauciones necesarias para obtener un modelo que defina con precisiĂłn la evoluciĂłn de la humedad en los bulbos hĂşmedos generados en suelos enarenados caracterĂsticos de los cultivos hortĂcolas intensivos. Se ha definido el procedimiento de toma y procesado de datos de humedad en suelos estratificados. Se ha ajustado experimentalmente la curva de retenciĂłn de humedad del suelo y permeabilidad para cada material. Se ha comprobado que el modelo Hydrus-3D puede reproducir el comportamiento de un suelo enarenado y se ha podido comprobar que las predicciones son adecuadas a lo observado en campo.INIA, Proyecto RTA2015-00029-C02-02, GestiĂłn Sostenible del RegadĂo en la Agricultura Intensiva de AndalucĂaZapata-Sierra, A.; Roldán-Cañas, J.; Reyes-Requena, R.; Moreno-PĂ©rez, M. (2021). CalibraciĂłn del Modelo Hydrus-3D para el riego localizado en suelos estratificados con cultivo intensivo (enarenado). IngenierĂa del agua. 25(1):1-14. https://doi.org/10.4995/ia.2021.13159OJS114251Amin, M.S.M., Ekhmaj, A.I.M. 2006. DIPAC-drip irrigation water distribution pattern calculator. 7th Int. Micro Irrigation Congress, PWTC, Kuala Lumpur, Malaysia, 10-12.Arbat, G., Puig-BarguĂ©s, J., Duran-Ros, M., Barragan, J., Cartagena, F. 2013. Drip-Irriwater: Computer software to simulate soil wetting patterns under surface drip irrigation. Computers and Electronics in Agriculture, 98, 183-192. https://doi.org/10.1016/j.compag.2013.08.009Bouyoucos, G.J. 1936. Directions for making mechanical analysis of soils by the hydrometer method. Soil Science, 42, 225-230. https://doi.org/10.1097/00010694-193609000-00007Brooks, R., Corey, T. 1964. Hydraulic properties of porous media. Hydrology Papers nÂş 3, Fort Collings. Colorado State University.Chu, S.T. 1994. Geen-Ampt Analysis of wetting patterns for surface emitters. Journal of Irrigation and Drainage Engineering, 120(2), 414-421. https://doi.org/10.1061/(ASCE)0733-9437(1994)120:2(414)Fernández, J.E., Moreno, F., Cabrera, F., Arrue, J.L., MartĂn-Aranda, J. 1991. Drip irrigation, soil characteristics and the root distribution and root activity of olive trees. Plant and soil, 133(2), 239-251. https://doi.org/10.1007/BF00009196Karmeli, D., Peri, G., Todes, M. 1985. Irrigation Systems: Design and Operation. Ed. Oxford University Press. Cape Town. Newman, E. 1966. A Method of Estimating the Total Length of Root in a Sample. Journal of Applied Ecology, 3(1), 139-145. https://doi.org/10.2307/2401670PĂ©rez, J., LĂłpez, J., Fernández, M.D. 2002. La agricultura del sureste: situaciĂłn actual y tendencias de las estructuras de producciĂłn en la horticultura almeriense, 2a. ediciĂłn Madrid: Editorial Caja Rural Intermediterránea.Schwartzman, M., Zur, B. 1986. Emitter spacing and geometry ofwetted soil volume. Journal of Irrigation and Drainage Engineering,112(3), 242-253. https://doi.org/10.1061/(ASCE)0733-9437(1986)112:3(242)Ĺ imunek, J., Van Genuchten, M.T., Ĺ ejna, M. 2012. HYDRUS: Model use, calibration, and validation. Transactions of the ASABE, 55(4), 1263-1274. https://doi.org/10.13031/2013.42239Van Genuchten, M.T. 1980. A closed-form equation for predicting the hydraulic conductivity of unsaturated soils 1. Soil science society of America journal, 44(5), 892-898. https://doi.org/10.2136/sssaj1980.03615995004400050002xVrugt, J., Hopmans, J., Ĺ imunek, J. 2001a. Calibration of a two-dimensional root water uptake model. Soil Science Society of America Journal, 65(4), 1027-1037. https://doi.org/10.2136/sssaj2001.6541027xVrugt, J.A., Van Wijk, M.T., Hopmans, J.W., Ĺ imunek, J. 2001b. One-, two-, and three-dimensional root water uptake functions for transient modeling. Water Resources Research, 37(10), 2457-2470. https://doi.org/10.1029/2000WR000027Willmott, C.J. 1981, On the Validation of Models. Physical Geography, 2(2), 184-194. https://doi.org/10.1080/02723646.1981.10642213Zapata-Sierra, A.J., LĂłpez-Segura, J.G., Cánovas-Fernández, G., Baeza-Cano, R. 2018. CaracterizaciĂłn del bulbo mojado por un gotero en suelos arenados mediante sondas fdr. XXXVI Congreso Nacional de Riegos, Valladolid, 2018, 1-8. https://doi.org/10.25028/CNRiegos.2018.A21Zapata-Sierra, A.J., Contreras, J., Usero, F., Baeza, R. 2015. Influencia de la textura del suelo en los bulbos hĂşmedos desarrollados en suelo enarenado con emisores de riego localizado de bajo caudal. XXXIII Congreso Nacional de Riegos Universitat Politècnica de València, Valencia 2015, 74-84. https://doi.org/10.4995/CNRiegos.2015.143
Geochemical influence of soil on leaf and grape (Vitis vinifera L. 'Cencibel') composition in La Mancha region (Spain)
The main purpose of the study was to evaluate major and trace elements contained in topsoil from representative plots of vineyards located in La Mancha, Spain, to obtain an elemental fingerprint of vines. The samples evaluated were obtained from topsoil in six different plots, belonging to the region of La Mancha, characterized by the cultivation of vineyards (near 189.127 ha). Twenty different vines from each plot were chosen to take samples from grapes, petioles and leaves. Analyses were carried out by X-ray Fluorescence applied on soils and dried vegetal matter. Biological Absorption Coefficient (BAC) was calculated to assess the uptake of minerals by vines as a function of their specific content in soil. The BAC in leaves and grapes was very similar for all studied elements. High contents of Ca, Sr, Ni and rare earth elements (La, Ce and Nd) were found along with low contents in Al, Zr, Ba, Cu, Zn and Pb, and normal contents in the rest of the elements. BAC in grapes was lower for the majority of the studied elements but it is interesting to underline the contents of Cs, K, Nb, Ce, Zn and Sr as possible markers of soil fingerprinting in the resulting wines.
Osteo-Chondroprogenitor–Specific Deletion of the Selenocysteine tRNA Gene, Trsp, Leads to Chondronecrosis and Abnormal Skeletal Development: A Putative Model for Kashin-Beck Disease
Kashin-Beck disease, a syndrome characterized by short stature, skeletal deformities, and arthropathy of multiple joints, is highly prevalent in specific regions of Asia. The disease has been postulated to result from a combination of different environmental factors, including contamination of barley by mold mycotoxins, iodine deficiency, presence of humic substances in drinking water, and, importantly, deficiency of selenium. This multifunctional trace element, in the form of selenocysteine, is essential for normal selenoprotein function, including attenuation of excessive oxidative stress, and for the control of redox-sensitive molecules involved in cell growth and differentiation. To investigate the effects of skeletal selenoprotein deficiency, a Cre recombinase transgenic mouse line was used to trigger Trsp gene deletions in osteo-chondroprogenitors. Trsp encodes selenocysteine tRNA[Ser]Sec, required for the incorporation of selenocysteine residues into selenoproteins. The mutant mice exhibited growth retardation, epiphyseal growth plate abnormalities, and delayed skeletal ossification, as well as marked chondronecrosis of articular, auricular, and tracheal cartilages. Phenotypically, the mice thus replicated a number of the pathological features of Kashin-Beck disease, supporting the notion that selenium deficiency is important to the development of this syndrome
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