HYPORHEIC NITRATE UPTAKE AND STOICHIOMETRIC LIMITATIONS: MESOCOSM EXPERIMENTS ALONG A RIVER CONTINUUM.

Nutrient uptake in streams and rivers is controlled by complex transport dynamics and biogeochemical interactions, which together regulate nutrient export from watersheds. Decoupling the relative contributions of transport and biogeochemical processes to nutrient uptake at the watershed scale has been challenging due to the spatial and temporal heterogeneity of physicochemical properties. Furthermore, logistical constraints have resulted in solute-specific analyses, primarily concentrated in headwater streams, that disregard the role of stoichiometry in controlling biological uptake. We used experimental mesocosm (column experiments) along the Jemez River-Rio Grande continuum (1st-8th stream order) to isolate spatial differences in biological nitrate uptake. Columns were constructed out of PVC, packed with gravel, silica sand and native sediments, and colonized in-situ for three months to allow the establishment of native microbial communities from each stream order. After incubation, we conducted two sets of tracer additions in each column under uniform flow conditions to analyze nitrate uptake for nitrate only injections and for stoichiometrically ‘balanced’ (106C:16N:1P) resource supply injections (i.e., nitrate vs Redfield experiments). We quantified NO3-N uptake kinetics using the TASCC method. We observed higher ranges of NO3-N uptake velocities relative to concentration during Redfield experiments. Highest nitrate uptake was observed in 7th order mesocosms packed with native sediments = 0.05 mm min-1). Nitrate kinetics predominantly followed Michaelis-Menten patterns. The comparison of the two injection experiments suggested that biological NO3-N processing was generally co-limited and the limitation varied with stream order and type of substrate. Our results support the notion that natural stoichiometric imbalances limit nutrient uptake in lotic systems and may explain the lack of scaling patterns observed in solute-specific nutrient uptake analyses

Potential bioavailability of representative pyrogenic organic matter compounds in comparison to natural dissolved organic matter pools

Pyrogenic organic matter (PyOM) from wildfires impacts river corridors globally and is widely regarded as resistant to biological degradation. Though recent work suggests PyOM may be more bioavailable than historically perceived, estimating bioavailability across its chemical spectrum remains elusive. To address this knowledge gap, we assessed potential bioavailability of representative PyOM compounds relative to ubiquitous dissolved organic matter (DOM) with a substrate-explicit model. The range of potential bioavailability of PyOM was greater than natural DOM; however, the predicted thermodynamics, metabolic rates, and carbon use efficiencies (CUEs) overlapped significantly between all OM pools. Compound type (e.g., natural versus PyOM) had approximately 6-fold less impact on predicted respiration rates than simulated carbon and oxygen limitations. Within PyOM, the metabolism of specific chemistries differed strongly between unlimited and oxygenlimited conditions – degradations of anhydrosugars, phenols, and polycyclic aromatic hydrocarbons (PAHs) were more favorable under oxygen limitation than other molecules. Notably, amino sugar-like, protein-like, and lignin-like PyOM had lower carbon use efficiencies relative to natural DOM of the same classes, indicating potential impacts in process-based model representations. Overall, our work illustrates how similar PyOM bioavailability may be to that of natural DOM in the river corridor, furthering our understanding of how PyOM may influence riverine biogeochemical cycling

Secretory leukoprotease inhibitor is required for efficient quercetin-mediated suppression of TNFα secretion

Dendritic cells (DCs) are professional antigen presenting cells (APCs) that in response to microbial infections generate long-lasting adaptive immune response. Following microbial uptake, DCs undergo a cascade of cellular differentiation that ultimately leads to “mature” DCs. Mature DCs produce a variety of inflammatory cytokines, including tumor necrosis factor-α (TNFα) a key cytokine for the inflammatory cascade. In numerous studies, polyphenols, including quercetin, demonstrated their ability to suppress TNFα secretion and protect from the onset of chronic inflammatory disorders. We show that murine bone marrow derived DCs express Slpi following quercetin exposure. Slpi is known to suppress LPS mediated NFκB activation, thus, it was hypothesized that its expression could be the key step for polyphenol induced inflammatory suppression. Slpi-KO DCs poorly respond to quercetin administration failing to reduce TNFα secretion in response to quercetin exposure. Supernatant from quercetin exposed DCs could also reduce LPS-mediated TNFα secretion by unrelated DCs, but this property is lost using an anti-Slpi antibody. In vivo, oral administration of quercetin is able to induce Slpi expression. Human biopsies from inflamed tract of the intestine reveal the presence of numerous SLPI(+) cells and the expression level could be further increased by quercetin administration. We propose that quercetin induces Slpi expression that in turn reduces the inflammatory response. Our data encourages the development of nutritional strategies to improve the efficiency of current therapies for intestinal chronic inflammatory syndrome and reduce the risks of colorectal cancer development

Servicios deportivos para promover el turismo sostenible. Revisión de la literatura.

Sustainable tourism has get strength, becoming a topic of global interest, where the preservation of resources and healthy lifestyles play an important role to guarantee the future of generations.   The purpose of the report is to present the relationship between sport and nature as a strategy to promote sustainable tourism focusing mainly on the offer of sports that can be practiced in natural environments considering the potential of the ecological resources of the department of Atlántico.  Within the bibliographic review, multiple publications were evidenced that by means of a characterization, 75 articles were chosen, these being refined under some acceptance criteria, selecting 20% ​​of the total, as they were the ones with the greatest contribution to the research objective. Likewise, a scientometric analysis of the search results was carried out based on key terms such as “sustainable tourims AND sports”. The results show that in last years , the tourism sector has had its greatest growth, and that it has also favored the economy and cultural values of the regions where it is developed. Associating sports and nature is increasingly common, however, it could affect the sustainabilityof natural resources. The conclusion obtained from this information is that sports and tourism practices in nature are an investment that generates benefits such as increased employment, economic diversification, business creation, cultural development, among others; However, they can also affect the biodiversity and natural resources of the region, so it is important to take the necessary preventive measures and involve government entities, the community and tourists.El turismo sostenible ha cobrado fuerza convirtiéndose en un tema de interés mundial, en el cual la preservación de los recursos y los hábitos de vida saludable juegan un papel importante para garantizar el futuro de las generaciones.  El presente documento tiene como propósito plantear la relación entre el deporte y la naturaleza como una estrategia para promover el turismo sostenible, enfocándose principalmente en la oferta de deportes que se pueden practicar en ambientes naturales considerando el potencial de los recursos ecológicos del departamento del Atlántico.  Dentro de la revisión bibliográfica se evidenciaron múltiples publicaciones que por medio de una caracterización se eligieron 75 artículos siendo estos depurados bajo unos criterios de aceptación, seleccionando el 20% del total, por ser los de mayor aporte para el objetivo de investigación. Así mismo se efectuó un análisis cienciométrico de los resultados de búsqueda basada en términos claves como “sustainable tourims AND sports”. Los resultados muestran que en los últimos años el sector turístico ha tenido su mayor crecimiento, y que además ha favorecido la economía y los valores culturales de las regiones donde se desarrolla. Asociar deportes y naturaleza es cada vez más común, no obstante, podría afectar la preservación de los recursos naturales.  Para concluir, las prácticas de deporte y turismo en la naturaleza resultan una inversión que favorece el incremento de empleo, la diversificación económica, la creación de empresas, el desarrollo cultural, entre otras; sin embargo, también pueden afectar la biodiversidad y los recursos naturales de la región, por ello es importante tomar las medidas preventivas necesarias e involucrar a las entidades gubernamentales, la comunidad y los turistas

Riverine organic matter functional diversity increases with catchment size

A large amount of dissolved organic matter (DOM) is transported to the ocean from terrestrial inputs each year (~0.95 Pg C per year) and undergoes a series of abiotic and biotic reactions, causing a significant release of CO2. Combined, these reactions result in variable DOM characteristics (e.g., nominal oxidation state of carbon, double-bond equivalents, chemodiversity) which have demonstrated impacts on biogeochemistry and ecosystem function. Despite this importance, however, comparatively few studies focus on the drivers for DOM chemodiversity along a riverine continuum. Here, we characterized DOM within samples collected from a stream network in the Yakima River Basin using ultrahigh-resolution mass spectrometry (i.e., FTICR-MS). To link DOM chemistry to potential function, we identified putative biochemical transformations within each sample. We also used various molecular characteristics (e.g., thermodynamic favorability, degradability) to calculate a series of functional diversity metrics. We observed that the diversity of biochemical transformations increased with increasing upstream catchment area and landcover. This increase was also connected to expanding functional diversity of the molecular formula. This pattern suggests that as molecular formulas become more diverse in thermodynamics or degradability, there is increased opportunity for biochemical transformations, potentially creating a self-reinforcing cycle where transformations in turn increase diversity and diversity increase transformations. We also observed that these patterns are, in part, connected to landcover whereby the occurrence of many landcover types (e.g., agriculture, urban, forest, shrub) could expand DOM functional diversity. For example, we observed that a novel functional diversity metric measuring similarity to common freshwater molecular formulas (i.e., carboxyl-rich alicyclic molecules) was significantly related to urban coverage. These results show that DOM diversity does not decrease along stream networks, as predicted by a common conceptual model known as the River Continuum Concept, but rather are influenced by the thermodynamic and degradation potential of molecular formula within the DOM, as well as landcover patterns

Blind Benchmark Exercise for Spent Nuclear Fuel Decay Heat

The decay heat rate of five spent nuclear fuel assemblies of the pressurized water reactor type were measured by calorimetry at the interim storage for spent nuclear fuel in Sweden. Calculations of the decay heat rate of the five assemblies were performed by 20 organizations using different codes and nuclear data libraries resulting in 31 results for each assembly, spanning most of the current state-of-the-art practice. The calculations were based on a selected subset of information, such as reactor operating history and fuel assembly properties. The relative difference between the measured and average calculated decay heat rate ranged from 0.6% to 3.3% for the five assemblies. The standard deviation of these relative differences ranged from 1.9% to 2.4%

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO