Océanos en el interior de los satélites de hielo

En las últimas tres décadas se ha especulado sobre la posible existencia de océanos internos en varios satélites de hielo del Sistema Solar exterior. Estas especulaciones se basaban en la posibilidad de calentamiento mareal, presencia de sustancias anticongelantes, u otras consideraciones teóricas. Los últimos años han comenzado a aparecer pruebas más directas a favor de la existencia de tales océanos, la más espectacular de las cuales es el descubrimiento de campos magnéticos inducidos en Europa, Ganímedes y Calisto, y quizá también en Ganímedes, originados en capas conductoras constituidas casi seguramente por agua líquida salada. Adicionalmente, las jóvenes superficies de Europa y Tritón se consideran evidencias indirectas de océanos internos. Los modelos teóricos recientes sobre el estado térmico de los satélites de hielo son consistentes con estas consideraciones

Book Review: Cold Aqueous Planetary Geochemistry with FREZCHEM – From Modeling to the Search for Life at the Limits Giles M. Marion, Jeffrey S. Kargel, Springer, 2008, 251 pp., ISBN: 978-3-540-75678-1 (US 119.00)

The original publication is available at www.springerlink.comDepto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

An origin for the linear magnetic anomalies on Mars through accretion of terranes: implications for dynamo timing

The proposed existence of magnetic lineations in the Terra Cimmeria and Terra Sirenum regions of Mars was initially explained by Earth-like sea-floor spreading. Here we argue instead that these lineations could have been formed at a convergent plate margin through collision and accretion of terranes. A similar process produced banded magnetic anomalies, similar in geometry and even in size to those in Earth’s North American Cordillera. Because only sparse and generally weak anomalies have been detected in the martian northern lowlands, which could constitute an analog to the terrestrial oceanic crust, it is possible that the magnetic field stopped its activity while crustal recycling was still active in Mars

Planetología reciente. Planetas terrestres y extrasolares

Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

The NADPH-Dependent thioredoxin reductase C-2-Cys peroxiredoxin redox system modulates the activity of thioredoxin x in arabidopsis chloroplasts

The chloroplast redox network is composed of a complex set of thioredoxins (Trxs), reduced by ferredoxin (Fdx) via a Fdx-dependent Trx reductase (FTR), and an NADPH-dependent Trx reductase with a joint Trx domain, NTRC, which efficiently reduces 2-Cys peroxiredoxins (2-Cys Prxs). Recently, it was proposed that the redox balance of 2-Cys Prxs maintains the redox state of f-type Trxs, thus allowing the proper redox regulation of Calvin-Benson cycle enzymes such as fructose 1,6-bisphosphatase (FBPase). Here, we have addressed whether the action of 2-Cys Prxs is also exerted on Trx x. To that end, an Arabidopsis thaliana quadruple mutant, ntrc-trxx-δ "2cp, which is knocked out for NTRC and Trx x, and contains severely decreased levels of 2-Cys Prxs, was generated. In contrast to ntrc-trxx, which showed a severe growth inhibition phenotype and poor photosynthetic performance, the ntrc-trxx-δ "2cp mutant showed a significant recovery of growth rate and photosynthetic efficiency, indicating that the content of 2-Cys Prxs is critical for the performance of plants lacking both NTRC and Trx x. Light-dependent reduction of FBPase was severely impaired in mutant plants lacking NTRC or NTRC plus Trx x, despite the fact that neither NTRC nor Trx x is an effective reductant of this enzyme. However, FBPase reduction was recovered in the ntrc-trxx-δ "2cp mutant. Our results show that the redox balance of 2-Cys Prxs, which is mostly dependent on NTRC, modulates the activity of Trx x in a similar way as f-type Trxs, thus suggesting that the activity of these Trxs is highly interconnected.Ministerio de Economía y Competitividad BIO2017-85195-C2-1-

Structure of the upper ice mantle of Triton

Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

Internet Access in Rural Areas: Brake or Stimulus as Post-Covid-19 Opportunity?

The lack of internet access in most rural areas has become a challenge worldwide. The Covid-19 pandemic has highlighted trends such as teleworking and e-commerce, meaning an opportunity for the local economy of these areas, but with serious difficulties in carrying it out. This paper aims to detect this lack of internet in inland areas of the region of Valencia through local actors, in order to identify clear priorities and real needs through an explorative and replicable approach based on agglomerative hierarchical clustering (AHC). The main findings suggest that there are different patterns in the rural internet access related to adequate infrastructure and planned actions by local councils. In this way, a multitude of contextual elements have emerged that influence the importance of efficient access to the internet in rural areas. It is essential to know the real needs and demands of the population before implementing plans and programs that may not be relevant for the actors involved in territorial development

A proposed reaction mechanism for rice NADPH thioredoxin reductase C, an enzyme with protein disulfide reductase activity

AbstractNADPH thioredoxin reductase C (NTRC) is an interesting NTR with a thioredoxin (Trx) domain at the C-terminus, able to conjugate both activities for 2-Cys peroxiredoxin (Prx) reduction. NTRC is dimeric in the presence of NADPH and interacted with dimeric 2-Cys Prx through the Trx module by a mixed disulfide between Cys377 of NTRC and Cys61 of the 2-Cys Prx. NTRC variants of both NTR and Trx active sites were inactive, but 1:1 mixtures of both variants allowed partial recovery of activity suggesting inter-subunit transfer of electrons during catalysis. Based on these results we propose a model for the reaction mechanism of NTRC.Structured summaryMINT-7017333: 2cys Prx (uniprotkb:Q6ER94) and 2cys Prx (uniprotkb:Q6ER94) bind (MI:0407) by molecular sieving (MI:0071)MINT-7017101, MINT-7017183: NTRC (uniprotkb:Q70G58) and 2cys Prx (uniprotkb:Q6ER94) bind (MI:0407) by enzymatic studies (MI:0415

"Does replication groups scoring reduce false positive rate in SNP interaction discovery?: Response"

<p>Abstract</p> <p/> <p>A response to Toplak et al: Does replication groups scoring reduce false positive rate in SNP interaction discovery? BMC Genomics 2010, 11:58.</p> <p>Background</p> <p>The genomewide evaluation of genetic epistasis is a computationally demanding task, and a current challenge in Genetics. HFCC (Hypothesis-Free Clinical Cloning) is one of the methods that have been suggested for genomewide epistasis analysis. In order to perform an exhaustive search of epistasis, HFCC has implemented several tools and data filters, such as the use of multiple replication groups, and direction of effect and control filters. A recent article has claimed that the use of multiple replication groups (as implemented in HFCC) does not reduce the false positive rate, and we hereby try to clarify these issues.</p> <p>Results/Discussion</p> <p>HFCC uses, as an analysis strategy, the possibility of replicating findings in multiple replication groups, in order to select a liberal subset of preliminary results that are above a statistical criterion and consistent in direction of effect. We show that the use of replication groups and the direction filter reduces the false positive rate of a study, although at the expense of lowering the overall power of the study. A post-hoc analysis of these selected signals in the combined sample could then be performed to select the most promising results.</p> <p>Conclusion</p> <p>Replication of results in independent samples is generally used in scientific studies to establish credibility in a finding. Nonetheless, the combined analysis of several datasets is known to be a preferable and more powerful strategy for the selection of top signals. HFCC is a flexible and complete analysis tool, and one of its analysis options combines these two strategies: A preliminary multiple replication group analysis to eliminate inconsistent false positive results, and a post-hoc combined-group analysis to select the top signals.</p