234 research outputs found
Diallel : Programa de anĂĄlisis estadĂstico para cruzamientos dialĂ©licos
A program in Pascal language was developed, to perform the analysisi of variance
and to estimate the combining abilities of diallelic crosses among lines according
to the methodology proposed by B. Griffing. The program considers eight different
cases related to four experimental methods and two models. A numerical example
is presented.Con base en Ia metodologĂa propuesta por B. Griffing se desarrollĂł un programa,
en el lenguaje Pascal, para efectuar el anĂĄlisis de varianza y estimar las habilidades
combinatorias de los cruces dialĂ©licos efectuados entre lineas de especies agrĂcolas o pecuarias. El programa contempla ocho casos diferentes de acuerdo a los cuatro mĂ©todos experimentales y los dos modelos existentes. Se presenta un ejemplo
numérico de uno de los casos
Recent discovery of an argyrolagid (Mammalia, Metatheria) for the Marplatan stage (middle Pliocene-early Pleistocene) of northwestern Argentina
We present the first remains of an argyrolagid from the UquĂa Formation (middle Pliocene-early Pleistocene; Marplatan) recovered at San Roque, Humahuaca, Jujuy Province, Argentina. The material is part of a microvertebrate fossil assemblage generated by trophic activity of predator birds that also includes amphibians, lizards, birds, rodents and didelphids. The remains represent three individuals and include fragments of maxilla and dentaries, and postcranial fragmentary bones (humeri, astragali, calcanei, and ungueal phalanges). The upper teeth show a simplified occlusal morphology, typical of this family. The most conspicuous features of lower teeth are: the presence of procumbent incisors, a mesiolabial expansion defining a shallow groove on m1, deep lingual groove absent on m1 and m2 but present on m3 and m4, m4 reduced with a deep labial groove and a shallow distal concavity. The morphology of lower molars (particularly, on m4 the deep labial groove and the distal shallow concavity) allows us to refer the material to Microtragulus bolivianus Hoffstetter and Villarroel. This species differs from other species of Microtragulus by: the absence of lingual groove on m1, labial groove of mesial lobe on m2, and lingual groove on m2, and the presence of larger m4 with a labial groove (M. reigi Simpson); its larger size, the deepest labial groove, and the presence of lingual groove on m3 and labial groove on m4 (M. catamarcensis [Kraglievich]); and by the absence of lingual groove on m1 and the presence of deeper labial grooves (M. rusconii Goin, Montalvo and Visconti). Rodents recorded in this assemblage (Microcavia, octodontids) are nowadays typical dwellers of dry and open areas, suggesting similar paleoenvironmental conditions for these levels of the UquĂa Formation. The presence of Microtragulus bolivianus in western Bolivia and northwestern Argentina suggests that a continuous area of xeric conditions was already established in this region by the end of the Pliocene.Sesiones libresFacultad de Ciencias Naturales y Muse
Effects of herbaceous covers and mineral fertilizers on the nutrient stocks and fluxes in a Mediterranean olive grove
Altres ajuts: acord transformatiu CRUE-CSICThe preservation of nutrient capital, soil fertility, and carbon (C) sequestration capacity in Mediterranean olive groves requires evaluation of agricultural practices beyond short-term productivity. We aim to contribute with a mechanistic understanding on the effects that the preservation of herbaceous cover and the use of chemical fertilizers have on the performance of olive trees and on the biogeochemical cycles of the agroecosystem. We compared nutrient fluxes and aboveground leafy stocks in an olive grove that had been organically managed for more than 60 years, in a treatment in which the annual spontaneous herbaceous cover was maintained (H), and after two years of shift to conventional management treatments in which the growth of herbaceous vegetation was avoided by the use of herbicides (NH), and where exclusion of the herbaceous cover is also combined with the supply of mineral fertilizers (NHF). Maintenance of herbaceous vegetation in H contributed to the retention of a high aboveground capital of C and nutrients, particularly nitrogen, (N), phosphorus (P) and potassium (K) that were about 2.9, 3.9 and 7.4 times greater than in NH, respectively. The permanence of herbaceous cover stimulated olive tree leaf litter decomposition rates by about 86 % and increased nutrient release. However, the H treatment led to a 37 % decrease in olive yield and lowered olive foliar N and P content as negative short-term effects. The addition of fertilizers (N, P, K, and Mg) in mineral and solid form in NHF resulted inefficient to improve olive tree nutritional status and olive production, and decelerated olive tree litter decomposition rates by 21 % and nutrient release. The nutrient retention in organic forms in the fast-growing species of herbaceous covers and the progressive nutrient release as litter decomposes may contribute to regulate and better adapt nutrient availability to the nutrient requirements of olive trees
A fossil lizard (Iguanoidea) from the upper Pliocene of northwestern Argentina
The Uquia Formation (middle Pliocene-lower Pleistocene) crops out in Quebrada de Humahuaca (Jujuy Province, northwestern Argentina) and contains an important record of fossil vertebrates that documents the event known as the Great American Biotic Interchange (GABI). We present a new fossil lizard from San Roque locality, near Humahuaca town, recovered in levels referred to late Pliocene. The material consists of one premaxilla, one maxilla, and several dentaries bearing teeth belonging to at least three individuals. The remains were part of a microvertebrate fossil assemblage that also includes amphibians, birds, rodents, and marsupials. Corrosion signals on the enamel of rodent teeth indicate that this assemblage was formed by the trophic activities of predatory birds. The phylogenetic analysis performed with 396 morphological characters places this new lizard as the sister taxon of a clade composed by Liolaemidae, Leiocephalidae, and Tropiduridae. Its uncertain position and substantial morphological differences justify its placement in a new genus. The results of this analysis support the monophyletic status of Iguanoidea and support other groups within Iguania. This is the first record of a Squamata for the Uquia Formation levels, which mainly contain medium to large sized mammals. The presence of extant rodent genera in the assemblage indicates arid paleoenvironmental conditions, similar to that currently found in the area.Sesiones libresFacultad de Ciencias Naturales y Muse
Large introns in relation to alternative splicing and gene evolution: a case study of Drosophila bruno-3
Background:
Alternative splicing (AS) of maturing mRNA can generate structurally and functionally distinct transcripts from the same gene. Recent bioinformatic analyses of available genome databases inferred a positive correlation between intron length and AS. To study the interplay between intron length and AS empirically and in more detail, we analyzed the diversity of alternatively spliced transcripts (ASTs) in the Drosophila RNA-binding Bruno-3 (Bru-3) gene. This gene was known to encode thirteen exons separated by introns of diverse sizes, ranging from 71 to 41,973 nucleotides in D. melanogaster. Although Bru-3's structure is expected to be conducive to AS, only two ASTs of this gene were previously described.
Results:
Cloning of RT-PCR products of the entire ORF from four species representing three diverged Drosophila lineages provided an evolutionary perspective, high sensitivity, and long-range contiguity of splice choices currently unattainable by high-throughput methods. Consequently, we identified three new exons, a new exon fragment and thirty-three previously unknown ASTs of Bru-3. All exon-skipping events in the gene were mapped to the exons surrounded by introns of at least 800 nucleotides, whereas exons split by introns of less than 250 nucleotides were always spliced contiguously in mRNA. Cases of exon loss and creation during Bru-3 evolution in Drosophila were also localized within large introns. Notably, we identified a true de novo exon gain: exon 8 was created along the lineage of the obscura group from intronic sequence between cryptic splice sites conserved among all Drosophila species surveyed. Exon 8 was included in mature mRNA by the species representing all the major branches of the obscura group. To our knowledge, the origin of exon 8 is the first documented case of exonization of intronic sequence outside vertebrates.
Conclusion:
We found that large introns can promote AS via exon-skipping and exon turnover during evolution likely due to frequent errors in their removal from maturing mRNA. Large introns could be a reservoir of genetic diversity, because they have a greater number of mutable sites than short introns. Taken together, gene structure can constrain and/or promote gene evolution
Human Rights and the Pink Tide in Latin America : Which Rights Matter?
Latin America witnessed the election of ânew Leftâ governments in the early 21 st century that, in different ways, sought to open a debate about alternatives to paradigms of neoliberal development. What has this meant for the way that human rights are understood and for patterns of human rights compliance? Using qualitative and quantitative evidence, this article discusses how human rights are imagined and the compliance records of new Left governments through the lens of the three âgenerationsâ of human rights â political and civil, social and economic, and cultural and environmental rights. The authors draw in particular on evidence from Andean countries and the Southern Cone. While basic civil and individual liberties are still far from guaranteed, especially in the Andean region, new Left countries show better overall performances in relation to socio-economic rights compared to the past and to other Latin American countries. All new Left governments also demonstrate an increasing interest in âthird generationâ (cultural and environmental) rights, though this is especially marked in the Andean Left. The authors discuss the tensions around interpretations and categories of human rights, reflect on the stagnation of first generation rights and note the difficulties associated with translating second and third generation rights into policy
The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment
The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in
operation since July 2014. This paper describes the second data release from
this phase, and the fourteenth from SDSS overall (making this, Data Release
Fourteen or DR14). This release makes public data taken by SDSS-IV in its first
two years of operation (July 2014-2016). Like all previous SDSS releases, DR14
is cumulative, including the most recent reductions and calibrations of all
data taken by SDSS since the first phase began operations in 2000. New in DR14
is the first public release of data from the extended Baryon Oscillation
Spectroscopic Survey (eBOSS); the first data from the second phase of the
Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2),
including stellar parameter estimates from an innovative data driven machine
learning algorithm known as "The Cannon"; and almost twice as many data cubes
from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous
release (N = 2812 in total). This paper describes the location and format of
the publicly available data from SDSS-IV surveys. We provide references to the
important technical papers describing how these data have been taken (both
targeting and observation details) and processed for scientific use. The SDSS
website (www.sdss.org) has been updated for this release, and provides links to
data downloads, as well as tutorials and examples of data use. SDSS-IV is
planning to continue to collect astronomical data until 2020, and will be
followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14
happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov
2017 (this is the "post-print" and "post-proofs" version; minor corrections
only from v1, and most of errors found in proofs corrected
Wood Utilization Is Dependent on Catalase Activities in the Filamentous Fungus Podospora anserina
Catalases are enzymes that play critical roles in protecting cells against the toxic effects of hydrogen peroxide. They are implicated in various physiological and pathological conditions but some of their functions remain unclear. In order to decipher the role(s) of catalases during the life cycle of Podospora anserina, we analyzed the role of the four monofunctional catalases and one bifunctional catalase-peroxidase genes present in its genome. The five genes were deleted and the phenotypes of each single and all multiple mutants were investigated. Intriguingly, although the genes are differently expressed during the life cycle, catalase activity is dispensable during both vegetative growth and sexual reproduction in laboratory conditions. Catalases are also not essential for cellulose or fatty acid assimilation. In contrast, they are strictly required for efficient utilization of more complex biomass like wood shavings by allowing growth in the presence of lignin. The secreted CATB and cytosolic CAT2 are the major catalases implicated in peroxide resistance, while CAT2 is the major player during complex biomass assimilation. Our results suggest that P. anserina produces external H2O2 to assimilate complex biomass and that catalases are necessary to protect the cells during this process. In addition, the phenotypes of strains lacking only one catalase gene suggest that a decrease of catalase activity improves the capacity of the fungus to degrade complex biomass
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