ARES: Adaptive, Reconfigurable, Erasure coded, atomic Storage

Atomicity or strong consistency is one of the fundamental, most intuitive, and hardest to provide primitives in distributed shared memory emulations. To ensure survivability, scalability, and availability of a storage service in the presence of failures, traditional approaches for atomic memory emulation, in message passing environments, replicate the objects across multiple servers. Compared to replication based algorithms, erasure code-based atomic memory algorithms has much lower storage and communication costs, but usually, they are harder to design. The difficulty of designing atomic memory algorithms further grows, when the set of servers may be changed to ensure survivability of the service over software and hardware upgrades, while avoiding service interruptions. Atomic memory algorithms for performing server reconfiguration, in the replicated systems, are very few, complex, and are still part of an active area of research; reconfigurations of erasure-code based algorithms are non-existent. In this work, we present ARES, an algorithmic framework that allows reconfiguration of the underlying servers, and is particularly suitable for erasure-code based algorithms emulating atomic objects. ARES introduces new configurations while keeping the service available. To use with ARES we also propose a new, and to our knowledge, the first two-round erasure code based algorithm TREAS, for emulating multi-writer, multi-reader (MWMR) atomic objects in asynchronous, message-passing environments, with near-optimal communication and storage costs. Our algorithms can tolerate crash failures of any client and some fraction of servers, and yet, guarantee safety and liveness property. Moreover, by bringing together the advantages of ARES and TREAS, we propose an optimized algorithm where new configurations can be installed without the objects values passing through the reconfiguration clients

Presentación

Me complace presentar el tercer número de nuestra revista Discursos del Sur, y más todavía porque es un número dedicado a Aníbal Quijano, recientemente fallecido. Quijano representó para las ciencias sociales en el Perú y América Latina lo que queremos que represente nuestra revista: el pensamiento crítico, la posibilidad de analizar la realidad a partir de un enfoque de conjunto, histórico y estructural, que permita no solo entenderla sino también transformarla. Quijano proyectó esta visión de pensamiento crítico desde temprano en su carrera académica e intelectual, perfilándose antes que nada como un productor de ideas que tendrían su realización al convertirse en herramientas de trabajo político para la liberación de los explotados y oprimidos de nuestra América y el mundo. Pero no fue cualquier tipo de intelectual, ni tampoco meramente un intelectual público, como se ha puesto de moda en los tiempos actuales, sino un intelectual orgánico de una visión del mundo que tenía en su núcleo la necesidad de socializar el poder. De esta manera, agonista como nos enseñara Mariátegui, vivió Quijano su tiempo, de principio a fin, produciendo ideas e inculcando esperanza transformadora.Me complace presentar el tercer número de nuestra revista Discursos del Sur, y más todavía porque es un número dedicado a Aníbal Quijano, recientemente fallecido. Quijano representó para las ciencias sociales en el Perú y América Latina lo que queremos que represente nuestra revista: el pensamiento crítico, la posibilidad de analizar la realidad a partir de un enfoque de conjunto, histórico y estructural, que permita no solo entenderla sino también transformarla. Quijano proyectó esta visión de pensamiento crítico desde temprano en su carrera académica e intelectual, perfilándose antes que nada como un productor de ideas que tendrían su realización al convertirse en herramientas de trabajo político para la liberación de los explotados y oprimidos de nuestra América y el mundo. Pero no fue cualquier tipo de intelectual, ni tampoco meramente un intelectual público, como se ha puesto de moda en los tiempos actuales, sino un intelectual orgánico de una visión del mundo que tenía en su núcleo la necesidad de socializar el poder. De esta manera, agonista como nos enseñara Mariátegui, vivió Quijano su tiempo, de principio a fin, produciendo ideas e inculcando esperanza transformadora

América Latina ante dos destinos democráticos diferentes

There exists an erroneous academic and political dilemma, propelled by the right, when characterizing the current course of Latin America as one that sits between democracy and dictatorship, as the only political horizons possible for the continent. On the contrary, the author affirms that this dispute is actually between elite democracies and social democracies. From this point, the author describes the political processes of the last decades in the region and proposes possible democratic horizons.Existe un equivocado dilema académico y político, impulsado desde la derecha, al momento de caracterizar la actualidad y el rumbo de América Latina entre la democracia o dictadura, como únicos horizontes posibles. En contraposición, el autor sostiene que la disputa se encuentra entre las democracias de élite y las democracias sociales. A partir de ello, describe los procesos políticos de las últimas décadas en la región y se plantea posibles horizontes democráticos

Presentación

Con este segundo número de la revista de teoría crítica en ciencias sociales Discursos del Sur continuamos el esfuerzo de publicar una revista académica impulsada desde la Unidad de Posgrado de la Facultad de Ciencias Sociales de la Universidad Nacional Mayor de San Marcos. Como en la oportunidad anterior nos hemos empeñado en la publicación de artículos que nos permitan entender mejor la difícil situación por la que atraviesa nuestra región latinoamericana y su proyección a futuro

Rural‐Urban Differences in In‐Hospital Mortality Among Admissions for End‐Stage Liver Disease in the United States

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151328/1/lt25587_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151328/2/lt25587.pd

PHAST: A Fast Phage Search Tool

PHAge Search Tool (PHAST) is a web server designed to rapidly and accurately identify, annotate and graphically display prophage sequences within bacterial genomes or plasmids. It accepts either raw DNA sequence data or partially annotated GenBank formatted data and rapidly performs a number of database comparisons as well as phage ‘cornerstone’ feature identification steps to locate, annotate and display prophage sequences and prophage features. Relative to other prophage identification tools, PHAST is up to 40 times faster and up to 15% more sensitive. It is also able to process and annotate both raw DNA sequence data and Genbank files, provide richly annotated tables on prophage features and prophage ‘quality’ and distinguish between intact and incomplete prophage. PHAST also generates downloadable, high quality, interactive graphics that display all identified prophage components in both circular and linear genomic views. PHAST is available at (http://phast.wishartlab.com)

The intriguing evolutionary dynamics of plant mitochondrial DNA

The mitochondrial genome of plants is-in every respect and for yet unclear reasons-very different from the well-studied one of animals. Thanks to next-generation sequencing technologies, Davila et al. precisely characterized the role played by recombination and DNA repair in controlling mitochondrial variations in Arabidopsis thaliana, thus opening new perspectives on the long-term evolution of this intriguing genome

Sixteen years of X-ray monitoring of Sagittarius A*: Evidence for a decay of the faint flaring rate from 2013 August, 13 months before a rise in the bright flaring rate

Recently, in a study the X-ray flaring activity of Sgr A* with Chandra and XMM-Newton public observations from 1999 to 2014 and 2014 Swift data, it has been argued that the "bright and very bright" flaring rate raised from 2014 Aug. 31. Thanks to 482ks of observations performed in 2015 with Chandra, XMM-Newton and Swift, we test the significance of this rise of flaring rate and determine the threshold of unabsorbed flare flux or fluence leading to any flaring-rate change. The mean unabsorbed fluxes of the 107 flares detected in the 1999-2015 observations are consistently computed from the extracted spectra and calibration files, assuming the same spectral parameters. We construct the observed flare fluxes and durations distribution for the XMM-Newton and Chandra flares and correct it from the detection biases to estimate the intrinsic distribution from which we determine the average flare detection efficiency for each observation. We apply the BB algorithm on the flare arrival times corrected from the corresponding efficiency. We confirm a constant overall flaring rate in 1999-2015 and a rise in the flaring rate for the most luminous/energetic flares from 2014 Aug. 31 (4 months after the passage of the DSO/G2 close to Sgr A*). We also identify a decay of the flaring rate for the less luminous and less energetic flares from 2013 Aug. and Nov., respectively (10 and 7 months before the pericenter of the DSO/G2). The decay of the faint flaring rate is difficult to explain by the tidal disruption of the DSO/G2, whose stellar nature is now well established, since it occurred well before its pericenter. Moreover, a mass transfer from the DSO/G2 to Sgr A* is not required to produce the rise in the bright flaring rate since the energy saved by the decay of the number of faint flares during a long time period may be later released by several bright flares during a shorter time period. (abridged)Comment: Accepted in A&A in 2017 April 2

Functional specialization of calreticulin domains

Calreticulin is a Ca2+-binding chaperone in the endoplasmic reticulum (ER), and calreticulin gene knockout is embryonic lethal. Here, we used calreticulin-deficient mouse embryonic fibroblasts to examine the function of calreticulin as a regulator of Ca2+ homeostasis. In cells without calreticulin, the ER has a lower capacity for Ca2+ storage, although the free ER luminal Ca2+ concentration is unchanged. Calreticulin-deficient cells show inhibited Ca2+ release in response to bradykinin, yet they release Ca2+ upon direct activation with the inositol 1,4,5-trisphosphate (InsP3). These cells fail to produce a measurable level of InsP3 upon stimulation with bradykinin, likely because the binding of bradykinin to its cell surface receptor is impaired. Bradykinin binding and bradykinin-induced Ca2+ release are both restored by expression of full-length calreticulin and the N + P domain of the protein. Expression of the P + C domain of calreticulin does not affect bradykinin-induced Ca2+ release but restores the ER Ca2+ storage capacity. Our results indicate that calreticulin may play a role in folding of the bradykinin receptor, which affects its ability to initiate InsP3-dependent Ca2+ release in calreticulin-deficient cells. We concluded that the C domain of calreticulin plays a role in Ca2+ storage and that the N domain may participate in its chaperone functions

Donor outcomes in anonymous live liver donation

BackgroundDeath rates on liver transplant waiting lists range from 5%-25%. Herein, we report a unique experience with 50 anonymous persons who volunteered to address this gap by offering to donate part of their liver to a recipient with whom they had no biological connection or prior relationship (A-LLD).MethodsCandidates were screened to confirm excellent physical, mental, social, and financial health. Demographics and surgical outcomes were analyzed. Qualitative interviews after donation examined motivation and experiences. Validated self-reported questionnaires assessed personality traits and psychological impact.Results50 A-LLD liver transplants (LT) were performed between 2005 and 2017. Most donors had a university education, a middle-class income, and a history of prior altruism. Half were women. Median age was 38.5 years (range 20-59 yrs.). Thirty-three (70%) learned about this opportunity through public or social media. Saving a life, helping others, generativity, and reciprocity for past generosity were motivators. Social, financial, healthcare, and legal supports in Canada were identified as facilitators. A-LLD identified most with the personality traits of agreeableness and conscientiousness. The median hospital stay was six days. There was one Dindo-Clavien Grade 3 complication that completely resolved. One-year recipient survival was 91% in 22 adults and 97% in 28 children. No A-LLD reported regretting their decision.ConclusionsThis is the first and only report of the motivations and facilitators of A-LLD in a large cohort. With rigorous protocols, outcomes are excellent. A-LLD has significant potential to reduce the gap between transplant organ demand and availability