Phosphorus export from catchments: a global view

16 pages, figures, and tables statistics.We reviewed global P export and its controlling factors from 685 world rivers. We used available continuous (runoff, rainfall, catchment area, % land use, and population density) and discrete (runoff type, soil type, biome, dominant land use, dominant type of forest, occurrence of stagnant water bodies in catchment, and Gross Product per Capita [GPC]) variables to predict export of P fractions. P export (kg P km22 y21) spanned 6 orders of magnitude worldwide. The distribution of all fractions of P export (total P [TP], soluble reactive P [SRP], and nonSRP [dissolved organic and particle-bound P]) was right skewed. Export of nonSRP had the highest coefficient of variability, and nonSRP was the dominant part of export. The available environmental variables predicted global P export fairly well (R2 = 0.73) if total N export was included in calculations. The unexplained variance in P export might be attributed to noise in the data set, inaccuracy of measurements of environmental variables at fine scales, lack of quantitative data on anthropogenic P sources, insufficient knowledge of P behavior in catchment soils, and nonlinearity of controlling processes. P exports were highly variable among catchment types, and runoff and population density were the predictors shared by most models. P export appeared to be controlled by different sets of environmental variables in different types of catchments. Quasi-empirical, mechanistic models of P export performed better than did empirical models. Our mechanistic understanding of P export could be improved by refining current analytical methods to obtain fast and reliable values of all P fractions in aquatic ecosystems and by incorporating better and more detailed data on catchment features, anthropogenic sources of P, and instream variables in a mechanistic modelling framework.Peer reviewe

Effects of shrimp-farm effluents on the food web structure in subtropical coastal lagoons

Received 4 October 2010, Revised 24 March 2011, Accepted 29 March 2011, Available online 19 April 2011Although numerous studies have reported the negative effects of shrimp aquaculture on water quality, little is known about the ecological effects of these practices in coastal lagoons and near-shore marine habitats. The impact of shrimp-farm effluents on the food webs of an impacted subtropical coastal lagoon in the Gulf of California was evaluated through measurements of isotopic (δ13C, δ15N) signatures in sediments, plants and animals, and compared with the results of a near-pristine reference site. Degradation was manifested in a strong reduction on fish diversity at the perturbed site. δ13C signatures provided ambiguous evidence of degradation while δ15N was a better descriptor of shrimp-farm effluent impact on coastal lagoon food webs. The site receiving nutrient-rich discharges showed significant enrichment of δ15N (≈ 5‰) in sediments, macroalgae, benthic algae, filterfeeders and omnivorous feeders, resulting in qualitative differences in foodweb structure between both lagoons. The food web in the perturbed site was sustained by sediment detritus and dominated by opportunistic species. The lowest influence on δ15N signatures by aquaculture discharges recorded in the upper trophic levels could be explained by the shift in the composition of biotic communities, and associated feeding strategies. While alterations in resource availability do not affect directly food chain length, trophic linkages between food web compartments can be reduced as a result of shrimp farm impacts. Our study demonstrates that nutrient-enriched discharges from shrimp-farm aquaculture generate changes in the availability of food sources, which reduce biodiversity and alter structural and functional food web characteristics.This research was supported by the Mexican Secretary of Natural Resources and Environment (SEMARNAT-CONACYT; contract SEMAR-NAT-2002-C01-0147) and by the Spanish Ministry of Environment (Organismo Autónomo Parques Nacionales; contracts 2008/001 DECA-MERON and 81/2005 CARBONDA.Peer reviewe

Enseñanza-Aprendizaje En La Estancia Clínica: Percepción Desde Los Estudiantes De Licenciatura En Enfermería

The clinical teaching of nursing graduates is one of the fundamental pillars for the development of knowledge, skills, attitudes, and values that would be projected in the real scenarios of their disciplinary practice. The expectation of any institution in professional formation in health discipline is that the facilitator should create an environment that is favorable for an effective teaching-learning process to take place. During the stay of the students in the healthcare institution, it is essential that they acquire a prospective, sensitive, and a specialized vision about their practice and the challenges they face in an increasingly complex society. There are a number of contradictions between theory and practice in care. This, however, leads to a clear gap which becomes evident in traditional teaching models. This requires a redirection towards innovative, humanistic, and specialized approaches to more dynamic ones in this information/knowledge society. The objective of this study was to obtain the perception of undergraduate nursing students on clinical teaching and whether it is related to the hospital context, experience, and teaching profile. Therefore, this favors an effective learning process. It is a quantitative, non-experimental, analytical, descriptive, cross-sectional, and prospective study with a convenience sample of 212 students in a sixth, seventh, and eighth semester of the clinical stationed (practice) class. Among the most important results of the research, it was found that the students stated that there is no functional relationship between Jean Watson's Human Care Theory and its application in the clinical field. They also perceived that this learning had a significant impact on several factors both of the Clinical environment and the educational institution. The study concludes that the students' perception of the teaching learning process oscillates between the contradiction of a theory that cannot be projected in practice and a series of factors that have a negative impact on the formation of their professional competence

Clonal reproduction of Azolla filiculoides Lam.: implications for invasiveness

Clonal reproduction of Azolla filiculoides Lam., an aquatic floating fern, native from the American subtropics and a recent invader of Mediterranean wetlands, was assessed experimentally. Shoot fragmentation of the species was quantified under suitable room conditions for optimum growth. Azolla fililculoides showed high longevity, a low mortality percentage and a high potential for clonal reproduction (biomass obtained by shoot fragmentation from only one individual was multiplied by 100). This last attribute changed over time: first generations developed a high number of propagules, a number which decreased progressively in later generations until the end of the experiment. The results of this experiment will be useful for understanding Azolla’s success within invaded habitats

Morphologic and genetic characterization of Pterygodermatites (Mesopectines) valladaresi n. sp. (Nematoda, Rictulariidae), a parasite of the mouse Mus musculus (Rodentia, Muridae) from the Canary Islands (Spain)

A new rictulariid nematode Pterygodermatites (Mesopectines) valladaresi n. sp., parasite of the house mouse Mus musculus (Rodentia: Muridae) in the Canary Islands (Spain) is described by means of light and scanning electron microscopy. The new species belongs to the subgenus Mesopectines characterized by a more or less dorsal orientation of the buccal capsule, the presence of three oesophageal teeth, the morphology of the oral denticles and the Spirurida type of arrangement of caudal papillae in males. The most discriminant characteristics between the new species and the existing species in the subgenus Mesopectines are (a) the number of cuticular projection pairs (62-64), (b) the size of right and left spicules (respectively, 62-90 µm and 123-139 µm), (c) the number of midventral fans in males (3-4), (d) the number of prevulvar/total cuticular projection pairs (38-42/63-71), (e) the posterior differentiation of combs into spines in relation to the position of the vulva and (f) the anterior position of the vulva in relation to the oesophagus-intestine junction in females. Parasitized hosts and geographical distribution are also useful criteria to distinguish P. (Me.) valladaresi n. sp. from the remaining species of the subgenus. In addition, the cox1 sequence of the new species is provided and compared with available data of related species. Keywords: Canary Islands; Muridae; Mus musculus; Pterygodermatites (Mesopectines) valladaresi n. sp.; Rictulariidae

Leaf Mass per Area of Wetland Vegetation under Water Stress Analyzed with Imaging Spectroscopy

Plant and community traits of wetland vegetation show a high intra-specific plasticity, originating from the high variability of environmental conditions. Remote sensing approaches promise to be able to retrieve some of these traits and their plasticity from the spectral reflectance signal of the canopy. In the present study, we evaluate a remote-sensing based approach for an analysis of spatial patterns of leaf mass per area (LMA), a key trait for ecosystem functioning and good negative correlate of potential growth rate. The test was conducted in Las Tablas de Daimiel, a National Park in Central Spain. This wetland was affected by a long-term drought, which introduced pronounced trait plasticity as part of the adaptation mechanisms of the vegetation to reduced water availability as well as a decrease in photosynthetic activity. Imaging spectroscopy (HyMap) data of the wetland were acquired in 2009 at peak drought intensity. At the same time, a field campaign was conducted. We applied an inversion of the PROSAIL model on these data to map the LMA distribution across the wetland. PROSAIL is a radiative transfer model that simulates the physical principles of light absorption and scattering in a vegetation canopy. The inversion enables the retrieval of trait information from the spectral signal. Furthermore, we assessed trends in photosynthetic activity and changing species composition across the wetland by analyzing time series of the normalized difference vegetation index (NDVI) as determined from various multispectral sensors. The mapped LMA values were analyzed within and between stands of different species and communities along a gradient of changing photosynthetic activity and species composition. LMA values retrieved for stands of species with high photosynthetic activity at peak drought intensity closely met values reported in trait data bases. The observed intra-specific LMA variability is in line with the expected plasticity of this trait along a moisture gradient that is reflected in a change in photosynthetic activity and species composition. We thus conclude that remote sensing approaches provide sufficient detail to trace the LMA-response of wetland vegetation to long-term drought stress

Temporal changes of NDVI for qualitative environmental assessment of mangroves: Shrimp farming impact on the health decline of the arid mangroves in the Gulf of California (1990-2010)

We assessed the temporal evolution of vegetation activity of mangroves in the Southeastern coastal of the Gulf of California (Mexico) through a multi-temporal analysis of Landsat TM images from 1990 to 2010 where time series of the Normalized Difference Vegetation Index (NDVI) were obtained. A multivariate regression analysis showed the presence of statistically significant negative trends of NDVI (low vegetation activity) in the coverage of mangrove forest, mangrove forest with pickleweed, and pickleweed; however, we did not found any meteorological variable (built time series of average minimum and maximum temperatures, and of accumulated rainfall) that controlled the observed trends. A pixel-by-pixel spatially distributed analysis of the temporal trends of NDVI, complemented by digitalization through photo interpretation of the shrimp farms present in the study area, showed a spatial relationship between the zones of greatest loss of vegetation activity (1990–2010) and the areas with greater proliferation of shrimp farms in the study area. Our study demonstrated the applicability of NDVI for the environmental assessment of mangroves. The relationship between changes in remote sensing indices and environmental variables allows for an efficient evaluation of the main environmental impacts, which can be used for coastal planning and management.The research was supported by the Mexican Secretary of Natural Resources and Environment (SEMARNAT-CONACYT; grant number SEMARNAT-2002-C01-0147). SM-B and RJM are students of Academic Program of Geoinformatics (UACJ).Peer Reviewe

CD38 Deficiency Ameliorates Chronic Graft-Versus-Host Disease Murine Lupus via a B-Cell-Dependent Mechanism

© 2021 Martínez-Blanco, Domínguez-Pantoja, Botía-Sánchez, Pérez-Cabrera, Bello-Iglesias, Carrillo-Rodríguez, Martin-Morales, Lario-Simón, Pérez-Sánchez-Cañete, Montosa-Hidalgo, Guerrero-Fernández, Longobardo-Polanco, Redondo-Sánchez, Cornet-Gomez, Torres-Sáez, Fernández-Ibáñez, Terrón-Camero, Andrés-León, O’Valle, Merino, Zubiaur and Sancho.The absence of the mouse cell surface receptor CD38 in Cd38−/− mice suggests that this receptor acts as a positive regulator of inflammatory and autoimmune responses. Here, we report that, in the context of the chronic graft-versus-host disease (cGVHD) lupus inducible model, the transfer of B6.C-H2bm12/KhEg(bm12) spleen cells into co-isogenic Cd38−/− B6 mice causes milder lupus-like autoimmunity with lower levels of anti-ssDNA autoantibodies than the transfer of bm12 spleen cells into WT B6 mice. In addition, significantly lower percentages of Tfh cells, as well as GC B cells, plasma cells, and T-bet+CD11chi B cells, were observed in Cd38−/− mice than in WT mice, while the expansion of Treg cells and Tfr cells was normal, suggesting that the ability of Cd38−/− B cells to respond to allogeneic help from bm12 CD4+ T cells is greatly diminished. The frequencies of T-bet+CD11chi B cells, which are considered the precursors of the autoantibody-secreting cells, correlate with anti-ssDNA autoantibody serum levels, IL-27, and sCD40L. Proteomics profiling of the spleens from WT cGVHD mice reflects a STAT1-driven type I IFN signature, which is absent in Cd38−/− cGVHD mice. Kidney, spleen, and liver inflammation was mild and resolved faster in Cd38−/− cGVHD mice than in WT cGVHD mice. We conclude that CD38 in B cells functions as a modulator receptor that controls autoimmune responses.S and MZ received financial support through “Proyecto del Plan Estatal”: SAF2017–89801-R. The IPBLN-CSIC Proteomics Unit belonged to ProteoRed-ISCIII (PRB2; PRB3) and was supported by grants PT13/0001/0011 (IPBLN-CSIC) and PT17/0019/0010 (CIB-CSIC; IPBLN-CSIC). RM: Project: SAF2017-82905-R. FO'V: Cátedra MIS IMPLANT-UGR. The stay of AC-G in Sancho’s lab was supported by a fellowship-contract JAE-Intro (CSIC). The stay of MD-P in Sancho’s lab was supported by a 1-year post-doctoral fellowship (Reference No. 502492) from the Consejo Nacional de Ciencia y Tecnología (CONACYT) of México. EA-L was recipient of a postdoctoral fellowship from the regional Andalusian Government