4,457 research outputs found
Transcription-mediated replication hindrance: a major driver of genome instability
Genome replication involves dealing with obstacles that
can result from DNA damage but also from chromatin alterations, topological stress, tightly bound proteins or
non-B DNA structures such as R loops. Experimental evidence reveals that an engaged transcription machinery at
the DNA can either enhance such obstacles or be an obstacle itself. Thus, transcription can become a potentially
hazardous process promoting localized replication fork
hindrance and stress, which would ultimately cause genome instability, a hallmark of cancer cells. Understanding the causes behind transcriptionâreplication conflicts
as well as how the cell resolves them to sustain genome
integrity is the aim of this review
Trade and Private R&D in Mexico
Using the National Survey on Employment, Wages, Technology and Training (Enestyc), this paper tries to find the relationship between increasing trade and the proportion of total income Mexican manufacturing firms invest on R&D. Based on two cross-sectional and a panel estimation procedures, the results confirm the idea that increasing the exposure to foreign markets affect the innovative efforts of Mexican firms. We also find that the firms engaging in some kind of R&D do not conform a random sample. More specifically, our results show that, in 1992, the probability of finding a firm engaging resources in some kind of R&D increased with size, a market diversification measure, and a measure of industrial market power at a 2-digit level, while the intensity of the R&D effort depended, on market power and an industry concentration measure. For the 1999 estimation our results show that the probability of R&D investment at a firm level increased with size, a market diversification measure, and exposure to foreign competition, while the magnitude of the R&D effort of a firm was determined by the decrease in average import tariffs at the industry level and by the exporting efforts of the firm. We find strong complementarities between public and private innovation efforts in both years, but find that younger firms are doing stronger R&D efforts in 1999. The 1992- 99 balanced panel results show that exporting firms invest more in R&D while import competing firms invest less, once size, market power and other control variables are taken into account. Our estimation indicates that exporting give firms a great incentive to innovate, and that not only large, but also small firms contribute to the R&D efforts of a nation.R&D, trade liberalization, foreign direct investment, exposure to foreing markets
Rpd3L and Hda1 histone deacetylases facilitate repair of broken forks by promoting sister chromatid cohesion
Genome stability involves accurate replication and DNA repair. Broken replication forks, such as those encountering a nick, lead to double strand breaks (DSBs), which are preferentially repaired by sister-chromatid recombination (SCR). To decipher the role of chromatin in eukaryotic DSB repair, here we analyze a collection of yeast chromatin-modifying mutants using a previously developed system for the molecular analysis of repair of replication-born DSBs by SCR based on a mini-HO site. We confirm the candidates through FLP-based systems based on a mutated version of the FLP flipase that causes nicks on either the leading or lagging DNA strands. We demonstrate that Rpd3L and Hda1 histone deacetylase (HDAC) complexes contribute to the repair of replication-born DSBs by facilitating cohesin loading, with no effect on other types of homology-dependent repair, thus preventing genome instability. We conclude that histone deacetylation favors general sister chromatid cohesion as a necessary step in SCR
"L'Umorismo" de Pirandello, una poética de tradición cervantina
El ensayo de Pirandello "L'umorismo" es muy importante para la literatura italiana del principio de este siglo, porque su poesĂa se explica claramente allĂ. La idea de humorismo es bastante diferente de la ironĂa y la comicidad, es un profundo pensamiento y produce un sentimiento contradictorio que el escritor utiliza para hacer su propia crĂtica de ficciĂłn. Este punto de vista fue una novedad en ese momento, sin embargo, Pirandello basa su arte en una gran tradiciĂłn donde Cervantes se revela como un maestro.Pirandello's essay âL'Umorismoâ is very important for the Italian Literature of the beginning of this century because his poetry is clearly explained there. The idea of humorism is rather different from irony and comicality, it is a deeply thought and produces a contradictory feeling that writer uses to do his own fictional criticism. This view was a novelty at that time, nevertheless, Pirandello bases his art on a large tradition where Cervantes is signed as a master.notPeerReviewe
Invisible pollution : emerging marine pollutants
Since the start of the Anthropocene, the planet has been threatened by a number of risks associated with human activity. Among them, chemical pollution is posing conceptual and technical challenges that are particularly difficult to characterise on a global scale. We must ask ourselves, what is a pollutant? What properties are relevant in their definition? Studies on the abundance, persistence, mobility in the environment, and bioaccumulation potential of the chemical compounds we use every day are changing the paradigm of what we consider pollutants. Thus, compounds that do not cause acute toxicity can still be dangerous for the ecosystem when they continually reach the environment, exist in very high concentrations, or disperse easily. Thus, raising awareness about the forgotten pollution that we unknowingly generate but which is affecting our oceans will be essential to protect the planet
Tourism Climatology: Past, Present and Future
Founded in 1999 at the 15th International Congress of Biometeorology, the Commission on Climate, Tourism and Recreation (CCTR) is an international working group that seeks to advance the current state of knowledge in the field of tourism/recreation climatology. Beginning in the 1970s, climatologists explored how climate impacts a myriad of economic sectors, including tourism, with research predominantly centered on how climatological information could be used within the context of tourism planning processes (Lamb 2002). After a brief decline in research activity in the 1980s, a new phase of research growth, propelled by climate change, emerged in the 1990s (Scott & Lemieux 2010). As noted by de Freitas (2017), the field is now truly multidisciplinary, with a range of disciplines contributing diverse methodologies to understand the climate and tourism nexus. Over the past five decades, the two-way relationship between climate and tourism that was once assumed is now empirically observed, objectively tested, and incorporates concepts and theoretical frameworks that support continued model development and global comparisons. The CCTR has facilitated and engaged the growing number of researchers in the field, building collaborative partnerships with industry leaders, identifying key knowledge gaps, and setting research priorities to continually advance the state of knowledg
Efficiently Storing Well-Composed Polyhedral Complexes Computed Over 3D Binary Images
A 3D binary image I can be naturally represented
by a combinatorial-algebraic structure called cubical complex
and denoted by Q(I ), whose basic building blocks are
vertices, edges, square faces and cubes. In Gonzalez-Diaz
et al. (Discret Appl Math 183:59â77, 2015), we presented a
method to âlocally repairâ Q(I ) to obtain a polyhedral complex
P(I ) (whose basic building blocks are vertices, edges,
specific polygons and polyhedra), homotopy equivalent to
Q(I ), satisfying that its boundary surface is a 2D manifold.
P(I ) is called a well-composed polyhedral complex over the
picture I . Besides, we developed a new codification system
for P(I ), encoding geometric information of the cells
of P(I ) under the form of a 3D grayscale image, and the
boundary face relations of the cells of P(I ) under the form
of a set of structuring elements. In this paper, we build upon
(Gonzalez-Diaz et al. 2015) and prove that, to retrieve topological
and geometric information of P(I ), it is enough to
store just one 3D point per polyhedron and hence neither
grayscale image nor set of structuring elements are needed.
From this âminimalâ codification of P(I ), we finally present
a method to compute the 2-cells in the boundary surface of
P(I ).Ministerio de EconomĂa y Competitividad MTM2015-67072-
Encoding Specific 3D Polyhedral Complexes Using 3D Binary Images
We build upon the work developed in [4] in which we presented
a method to âlocally repairâ the cubical complex Q(I) associated
to a 3D binary image I, to obtain a âwell-composedâ polyhedral complex
P(I), homotopy equivalent to Q(I). There, we developed a new codification
system for P(I), called ExtendedCubeMap (ECM) representation,
that encodes: (1) the (geometric) information of the cells of P(I) (i.e.,
which cells are presented and where), under the form of a 3D grayscale
image gP ; (2) the boundary face relations between the cells of P(I),
under the form of a set BP of structuring elements.
In this paper, we simplify ECM representations, proving that geometric
and topological information of cells can be encoded using just a 3D
binary image, without the need of using colors or sets of structuring
elements. We also outline a possible application in which well-composed
polyhedral complexes can be useful.Junta de AndalucĂa FQM-369Ministerio de EconomĂa y Competitividad MTM2012-32706Ministerio de EconomĂa y Competitividad MTM2015-67072-
Spatiotemporal Barcodes for Image Sequence Analysis
Taking as input a time-varying sequence of two-dimensional
(2D) binary images, we develop an algorithm for computing a spatiotemporal
0âbarcode encoding lifetime of connected components on the image
sequence over time. This information may not coincide with the one provided
by the 0âbarcode encoding the 0âpersistent homology, since the
latter does not respect the principle that it is not possible to move backwards
in time. A cell complex K is computed from the given sequence,
being the cells of K classified as spatial or temporal depending on whether
they connect two consecutive frames or not. A spatiotemporal path is
defined as a sequence of edges of K forming a path such that two edges
of the path cannot connect the same two consecutive frames. In our
algorithm, for each vertex v â K, a spatiotemporal path from v to the
âoldestâ spatiotemporally-connected vertex is computed and the corresponding
spatiotemporal 0âbar is added to the spatiotemporal 0âbarcode.Junta de AndalucĂa FQM-369Ministerio de EconomĂa y Competitividad MTM2012-3270
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