The ultracool dwarf DENIS-P J104814.7-395606. Chromospheres and coronae at the low-mass end of the main-sequence

We have obtained an XMM-Newton observation and a broad-band spectrum from the ultraviolet to the near infrared with X-Shooter for one of the nearest M9 dwarfs, DENIS-P J1048-3956 (4pc). We integrate these data by a compilation of activity parameters for ultracool dwarfs from the literature with the aim to advance our understanding of these objects by comparing them to early-M type dwarf stars and the Sun. Our deep XMM-Newton observation has led to the first X-ray detection of DENIS-P J1048-3956 (log Lx = 25.1) as well as the first measurement of its V band brightness (V = 17.35mag). Flux-flux relations between X-ray and chromospheric activity indicators are here for the first time extended into the regime of the ultracool dwarfs. The approximate agreement of DENIS-P J1048-3956 and other ultracool dwarfs with flux-flux relations for early-M dwarfs suggests that the same heating mechanisms work in the atmospheres of ultracool dwarfs, albeit weaker as judged from their lower fluxes. The observed Balmer decrements of DENIS-P J1048-3956 are compatible with optically thick plasma in LTE at low, nearly photospheric temperature or optically thin LTE plasma at 20000K. Describing the decrements with CaseB recombination requires different emitting regions for Halpha and the higher Balmer lines. The high observed Halpha/Hbeta flux ratio is also poorly fitted by the optically thin models. We derive a similarly high value for the Halpha/Hbeta ratio of vB10 and LHS2065 and conclude that this may be a characteristic of ultracool dwarfs. We add DENIS-P J1048-3956 to the list of ultracool dwarfs detected in both the radio and the X-ray band. The Benz-Guedel relation between radio and X-ray luminosity of late-type stars is well-known to be violated by ultracool dwarfs. We speculate on the presence of two types of ultracool dwarfs with distinct radio and X-ray behavior.Comment: accepted for publication in Astronomy & Astrophysic

The Origin of Amerindians and the Peopling of the Americas According to HLA Genes: Admixture with Asian and Pacific People

The classical three-waves theory of American peopling through Beringia was based on a mixed anthropological and linguistic methodology. The use of mtDNA, Y chromosome and other DNA markers offers different results according to the different markers and methodologies chosen by different authors. At present, the peopling of Americas remains uncertain, regarding: time of population, number of peopling waves and place of peopling entrance among other related issues. In the present review, we have gathered most available HLA data already obtained about First Native American populations, which raise some doubts about the classical three waves of American peopling hypothesis. In summary, our conclusions are: 1) North West Canadian Athabaskans have had gene flow with: a) close neighboring populations, b) Amerindians, c) Pacific Islanders including East Australians and d) Siberians; 2) Beringia was probably not the only entrance of people to America: Pacific Ocean boat trips may have contributed to the HLA genetic American profile (or the opposite could also be true); 3) Amerindians entrance to America may have been different to that of Athabaskans and Eskimos and Amerindians may have been in their lands long before Athabaskans and Eskimos because they present and altogether different set of HLA-DRB1 allele frequencies; 4) Amerindians show very few “particular alleles”, almost all are shared with other Amerindians, Athabaskans and Pacific Islanders, including East Australians and Siberians; 5) Our results do not support the three waves model of American peopling, but another model where the people entrance is not only Beringia, but also Pacific Coast. Reverse migration (America to Asia) is not discarded and different movements of people in either direction in different times are supported by the Athabaskan population admixture with Asian-Pacific population and with Amerindians, 6) HLA variability is more common than allele veriability in Amerindians. Finally, it is shown that gene genealogy analises should be completed with allele frequency analyses in population relatednes and migrations studies

Estudio de la expresión de ghrelina en el píloro de ratones NOD y NOD/Scid de 32 semanas

La diabetes mellitus (DM) es un conjunto de enfermedades metabólicas caracterizada por una concentración elevada de glucosa en sangre y en orina; debido a una disminución en la secreción de la hormona insulina o a una deficiencia en la acción de la misma. Los non-obese diabetic mice (ratones NOD) desarrollan DM1 de manera espontánea con una patología similar a la que cursa en el ser humano. En este modelo animal se produce un ataque autoinmune contra las células beta pancreáticas provocando una infiltración linfocitaria en los islotes de Langerhans, que dará lugar a una insulitis y a la destrucción del área endocrina del órgano. La ghrelina es una hormona peptídica que es sintetizada predominantemente en el estómago y cuyas funciones principales son regular el apetito e inhibir la liberación de insulina por parte de las células beta pancreáticas. Por lo contrario, las incretinas como GLP-1 o GIP son hormonas intestinales cuyo efecto más importante es la estimulación en la secreción de insulina. En este trabajo se ha estudiado la expresión de la ghrelina, mediante técnicas inmunohistoquímicas, en el píloro de ratones NOD y NOD/Scid de 32 semanas de edad. Para ello, se han empleado cortes histológicos de 9 ratones NOD y 9 ratones NOD/Scid, utilizados como control. Tras el recuento de las células inmunorreactivas (IR) para ghrelina en el píloro de los ratones se ha calculado la densidad celular por mm2 de mucosa pilórica. Se ha observado una disminución no significativa de la densidad de células IR para ghrelina en el píloro de ratones NOD con respecto al grupo control. También se ha observado una disminución no significativa de la densidad de células IR para ghrelina en el píloro de ratones NOD hiperglucémicos (NODH) con respecto a los ratones NOD normoglucémicos (NODN) de 32 semanas de edad

Incidence of the protozoan Perkinsus sp. on a cultivated population of the carpet shell clam Ruditapes decussatus (L., 1758) in the Arousa ria (northwestern Spain)

La almeja fina Ruditapes decussatus L., 1758 es una especie importante en el sector pesquero gallego, con una producción que se ha situado en 760 t en el año 2000. La escasa información disponible sobre el crecimiento de esta especie establece en cuatro años el tiempo necesario para alcanzar la talla legal de extracción: 40 mm de longitud. En este trabajo se obtiene el mismo crecimiento en 27 meses y se muestra la importancia del sustrato sobre el crecimiento y el índice de condición, así como la incidencia de la infección por Perkinsus sp., que consigue prevalencias (porcentaje de almejas infectadas) de hasta el 100%.The carpet shell clam Ruditapes decussatus L., 1758 is a major species in the fishery of Galicia (northwestern Spain), with a production of 760 t in 2000. Information regarding the growth of this species is scarce, and it was formerly estimated that it took 4 years to achieve the legal size (40 mm length). However, the present paper shows that the same length can be obtained in 27 months. The importance of the substrate on the species's growth and condition index is also discussed, as well as the infestation of Perkinsus sp., with a prevalence as high as 100%.Instituto Español de Oceanografí

Nitrous Oxide Abatement Coupled with Biopolymer Production As a Model GHG Biorefinery for Cost-Effective Climate Change Mitigation

Producción CientíficaN2O represents ∼6% of the global greenhouse gas emission inventory and the most important O3-depleting substance emitted in this 21st century. Despite its environmental relevance, little attention has been given to cost-effective and environmentally friendly N2O abatement methods. Here we examined, the potential of a bubble column (BCR) and an internal loop airlift (ALR) bioreactors of 2.3 L for the abatement of N2O from a nitric acid plant emission. The process was based on the biological reduction of N2O by Paracoccus denitrificans using methanol as a carbon/electron source. Two nitrogen limiting strategies were also tested for the coproduction of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) coupled with N2O reduction. High N2O removal efficiencies (REs) (≈87%) together with a low PHBV cell accumulation were observed in both bioreactors in excess of nitrogen. However, PHBV contents of 38–64% were recorded under N limiting conditions along with N2O-REs of ≈57% and ≈84% in the ALR and BCR, respectively. Fluorescence in situ hybridization analyses showed that P. denitrificans was dominant (>50%) after 6 months of experimentation. The successful abatement of N2O concomitant with PHBV accumulation confirmed the potential of integrating biorefinery concepts into biological gas treatment for a cost-effective GHG mitigation.Ministerio de Economía, Industria y Competitividad (Proyect CTM2015-70442-R and Red NOVEDAR CTQ2014-51693-REDC

Author Correction: A HIF independent oxygen-sensitive pathway for controlling cholesterol synthesis (Nature Communications, (2023), 14, 1, (4816), 10.1038/s41467-023-40541-1)

\ua9 The Author(s) 2024.The original version of this Article contained errors in Figs. 2, 3, and 5. In the original Fig. 2e, the flow cytometry panel on the right (labelled “StD (24 hr) followed by 1% O2 (~16 hr)”), was inadvertently duplicated from the panel on the left (labelled “Concurrent StD and 1% O2 (~24 hr)”). In the original Fig. 3a, the flow cytometry panel on the right (labelled “Roxadustat”), was inadvertently duplicated from the panel on the left (labelled “DMOG”). In the original Fig. 5c, the labels did not properly communicate that both panels come from the same experiment and have the same controls. The following sentence has been added to the end of the legend for Fig. 5c: “The data depicted in the left and right panels originated from the same experiment and as such the control plots are the same in both.” Figures 2, 3, and 5 have been corrected in both the PDF and HTML versions of the Article. The original version of the Supplementary Information associated with this Article contained an error in Supplementary Fig. 5. In the original Supplementary Fig. 5a, the labels did not properly communicate that all three panels come from the same experiment and have the same control. The following sentence has been added to the end of the legend for Supplementary Fig. 5a: “The data depicted in the three panels originated from the same experiment and as such the control plot is the same in all panels”. The HTML has been updated to include a corrected version of the Supplementary Information