Nitrate and Phosphorus Transport in a Galician River (NW Iberian Peninsula): Insights From Fourteen Years of Monitoring

This article is part of the special issue Current Research on Soil Science and Related Aspects of Environmental Sciences in Galicia[Abstract] The long-term development of water quality metrics is critical to estimate the status of water resources and successful catchment management. This study looks at the temporal evolution of nitrate and phosphorus loads and concentrations in a stream draining rural catchment in Galicia (NW Iberian Peninsula) during 14 hydrological years. The concentrations of both nutrients are relatively low because of the rural nature of the research catchment and low-intensity agriculture. However, catchment nutrient reference levels were widely exceeded. The hydrology controls nutrient fluxes as flow is the main driver of nutrient transfer. For both nutrients there were no consistent trends in nutrient fluxes. The analysed nutrients, however, have been seen to behave differently. As a result, N seems to be decreasing, mainly due to decreased transit in the autumn and spring. Phosphorus, which is primarily transported as particulate matter, exhibits an increase in winter linked to a greater flow and sediment transfer.This research was carried out within the projects REN2003-08143, funded by the Spanish Ministry of Education and Science, and PGIDIT05RAG10303PR and 10MDS103031PR, financed by the Xunta of GaliciaXunta de Galicia; PGIDIT05RAG10303PRXunta de Galicia; 10MDS103031P

Garvicins AG1 and AG2 : two novel class IId bacteriocins of lactococcus garvieae Lg-Granada

Funding: This research was funded by the Spanish Ministry of Science, Innovation, and Universities, grant number RTI2018-098530-B-I00. The APC was funded by the Spanish Ministry of Science, Innovation, and Universities, grant number RTI2018-098530-B-I00.Lactococcus garvieae causes infectious diseases in animals and is considered an emerging zoonotic pathogen involved in human clinical conditions. In silico analysis of plasmid pLG50 of L. garvieae Lg-Granada, an isolate from a patient with endocarditis, revealed the presence of two gene clusters (orf 46–47 and orf 48–49), each one encoding a novel putative bacteriocin, i.e., garvicin AG1 (GarAG1; orf 46) and garvicin AG2 (GarAG2; orf 48), and their corresponding immunity proteins (orf 47 and orf 49). The chemically synthesised bacteriocins GarAG1 and GarAG2 presented inhibitory activity against pathogenic L. garvieae strains, with AG2 also being active against Listeria monocytogenes, Listeria ivanovii and Enterococcus faecalis. Genetic organisation, amino acid sequences and antimicrobial activities of GarAG1 and GarAG2 indicate that they belong to linear non-pediocin-like one-peptide class IId bacteriocins. Gram-positive bacteria that were sensitive to GarAG2 were also able to ferment mannose, suggesting that this bacteriocin could use the mannose phosphotransferase transport system (Man-PTS) involved in mannose uptake as a receptor in sensitive strains. Intriguingly, GarAG1 and GarAG2 were highly active against their own host, L. garvieae Lg-Granada, which could be envisaged as a new strategy to combat pathogens via their own weapons.Publisher PDFPeer reviewe

Black Rings in Taub-NUT and D0-D6 interactions

We analyze the dynamics of neutral black rings in Taub-NUT spaces and their relation to systems of D0 and D6 branes in the supergravity approximation. We employ several recent techniques, both perturbative and exact, to construct solutions in which thermal excitations of the D0-branes can be turned on or off, and the D6-brane can have $B$-fluxes turned on or off in its worldvolume. By explicit calculation of the interaction energy between the D0 and D6 branes, we can study equilibrium configurations and their stability. We find that although D0 and D6 branes (in the absence of $B$ fields, and at zero temperature) repeal each other at non-zero separation, as they get together they go over continuosly to an unstable bound state of an extremal singular Kaluza-Klein black hole. We also find that, for $B$-fields larger than a critical value, or sufficiently large thermal excitation, the D0 and D6 branes form stable bound states. The bound states with thermally excited D0 branes are black rings in Taub-NUT, and we provide an analysis of their phase diagram.Comment: 50 pages, 8 figures; v3: minor changes and references added; v4: improved figs. 7 and 8, matches with published versio

Phenomenology of a Pseudo-Scalar Inflaton: Naturally Large Nongaussianity

Many controlled realizations of chaotic inflation employ pseudo-scalar axions. Pseudo-scalars \phi are naturally coupled to gauge fields through c \phi F \tilde{F}. In the presence of this coupling, gauge field quanta are copiously produced by the rolling inflaton. The produced gauge quanta, in turn, source inflaton fluctuations via inverse decay. These new cosmological perturbations add incoherently with the "vacuum" perturbations, and are highly nongaussian. This provides a natural mechanism to generate large nongaussianity in single or multi field slow-roll inflation. The resulting phenomenological signatures are highly distinctive: large nongaussianity of (nearly) equilateral shape, in addition to detectably large values of both the scalar spectral tilt and tensor-to-scalar ratio (both being typical of large field inflation). The WMAP bound on nongaussianity implies that the coupling, c, of the pseudo-scalar inflaton to any gauge field must be smaller than about 10^{2} M_p^{-1}.Comment: 45 pages, 7 figure

Axion-like particles as ultra high energy cosmic rays?

If Ultra High Energy Cosmic Rays (UHECRs) with E>4 10^{19} eV originate from BL Lacertae at cosmological distances as suggested by recent studies, the absence of the GZK cutoff can not be reconciled with Standard-Model particle properties. Axions would escape the GZK cutoff, but even the coherent conversion and back-conversion between photons and axions in large-scale magnetic fields is not enough to produce the required flux. However, one may construct models of other novel (pseudo)scalar neutral particles with properties that would allow for sufficient rates of particle production in the source and shower production in the atmosphere to explain the observations. As an explicit example for such particles we consider SUSY models with light sgoldstinos.Comment: 5 pages, 2 postscript figures, ref. adde

Drum vortons in high density QCD

Recently it was shown that high density QCD supports of number of topological defects. In particular, there are U(1)_Y strings that arise due to K^0 condensation that occurs when the strange quark mass is relatively large. The unique feature of these strings is that they possess a nonzero K^+ condensate that is trapped on the core. In the following we will show that these strings (with nontrivial core structure) can form closed loops with conserved charge and currents trapped on the string worldsheet. The presence of conserved charges allows these topological defects, called vortons, to carry angular momentum, which makes them classically stable objects. We also give arguments demonstrating that vortons carry angular momentum very efficiently (in terms of energy per unit angular momentum) such that they might be the important degrees of freedom in the cores of neutron stars.Comment: 11 pages, accepted for publication in Physical Review

The pandemic brain: Neuroinflammation in non-infected individuals during the COVID-19 pandemic

While COVID-19 research has seen an explosion in the literature, the impact of pandemic-related societal and lifestyle disruptions on brain health among the uninfected remains underexplored. However, a global increase in the prevalence of fatigue, brain fog, depression and other “sickness behavior”-like symptoms implicates a possible dysregulation in neuroimmune mechanisms even among those never infected by the virus. We compared fifty-seven ‘Pre-Pandemic’ and fifteen ‘Pandemic’ datasets from individuals originally enrolled as control subjects for various completed, or ongoing, research studies available in our records, with a confirmed negative test for SARS-CoV-2 antibodies. We used a combination of multimodal molecular brain imaging (simultaneous positron emission tomography / magnetic resonance spectroscopy), behavioral measurements, imaging transcriptomics and serum testing to uncover links between pandemic-related stressors and neuroinflammation. Healthy individuals examined after the enforcement of 2020 lockdown/stay-at-home measures demonstrated elevated brain levels of two independent neuroinflammatory markers (the 18 kDa translocator protein, TSPO, and myoinositol) compared to pre-lockdown subjects. The serum levels of two inflammatory markers (interleukin-16 and monocyte chemoattractant protein-1) were also elevated, although these effects did not reach statistical significance after correcting for multiple comparisons. Subjects endorsing higher symptom burden showed higher TSPO signal in the hippocampus (mood alteration, mental fatigue), intraparietal sulcus and precuneus (physical fatigue), compared to those reporting little/no symptoms. Post-lockdown TSPO signal changes were spatially aligned with the constitutive expression of several genes involved in immune/neuroimmune functions. This work implicates neuroimmune activation as a possible mechanism underlying the non-virally-mediated symptoms experienced by many during the COVID-19 pandemic. Future studies will be needed to corroborate and further interpret these preliminary findings

Sentinels of Seabed (SoS) indicator: Assessing benthic habitats condition using typical and sensitive species

Indicators are key tools used to assess the ecological status of the environment for ecosystem based management. Anthropogenic disturbances produce changes to habitat condition, which include modifications in species composition and their functions. Monitoring a group of sentinel species (from a taxonomic and functional point of view) provides useful insights into benthic habitat condition. Here, a new indicator, Sentinels of the Seabed (SoS) is proposed to assess state of benthic habitats using “sentinel” species (species which are characteristic of a habitat and sensitive to a given pressure). The selection of these sentinel species has two stages. First, a ‘typical species set’ is computed using intra-habitat similarity and frequency under reference conditions. Second, the ‘sentinel species set’ is generated by selecting the most sensitive species from the typical species set. This selection is made using specific indexes able to assess species sensitivity to a particular pressure. The SoS indicator method was tested on six case studies and two different pressure types (trawling disturbance and pollution), using data from otter trawl, box-corer and Remote Operate Vehicle images. In each scenario, the SoS indicator was compared to the Shannon-Wiener diversity index, Margalef index and total biomass, being the only metric, which showed the expected significant negative response to pressure in all cases. Our results shows that SoS was highly effective in assessing benthic habitats status under both physical and chemical pressures, regardless of the sampling gear, the habitat, or the case study, showing a great potential to be a useful tool in the management of marine ecosystems.Versión del editor2,69