Astrometric performance of the Gemini multi-conjugate adaptive optics system in crowded fields

The Gemini Multi-conjugate adaptive optics System (GeMS) is a facility instrument for the Gemini-South telescope. It delivers uniform, near-diffraction-limited image quality at near-infrared wavelengths over a 2 arcminute field of view. Together with the Gemini South Adaptive Optics Imager (GSAOI), a near-infrared wide field camera, GeMS/GSAOI's combination of high spatial resolution and a large field of view will make it a premier facility for precision astrometry. Potential astrometric science cases cover a broad range of topics including exo-planets, star formation, stellar evolution, star clusters, nearby galaxies, black holes and neutron stars, and the Galactic center. In this paper, we assess the astrometric performance and limitations of GeMS/GSAOI. In particular, we analyze deep, mono-epoch images, multi-epoch data and distortion calibration. We find that for single-epoch, un-dithered data, an astrometric error below 0.2 mas can be achieved for exposure times exceeding one minute, provided enough stars are available to remove high-order distortions. We show however that such performance is not reproducible for multi-epoch observations, and an additional systematic error of ~0.4 mas is evidenced. This systematic multi-epoch error is the dominant error term in the GeMS/GSAOI astrometric error budget, and it is thought to be due to time-variable distortion induced by gravity flexure.Comment: 16 pages, 22 figures, accepted for publication in MNRA

The stellar mass - size relation for cluster galaxies at z=1 with high angular resolution from the Gemini/GeMS multi-conjugate adaptive optics system

We present the stellar mass - size relation for 49 galaxies within the $z$ = 1.067 cluster SPT-CL J0546$-$5345, with FWHM $\sim$80-120 mas $K_{\mathrm s}$-band data from the Gemini multi-conjugate adaptive optics system (GeMS/GSAOI). This is the first such measurement in a cluster environment, performed at sub-kpc resolution at rest-frame wavelengths dominated by the light of the underlying old stellar populations. The observed stellar mass - size relation is offset from the local relation by 0.21 dex, corresponding to a size evolution proportional to $(1+z)^{-1.25}$, consistent with the literature. The slope of the stellar mass - size relation $\beta$ = 0.74 $\pm$ 0.06, consistent with the local relation. The absence of slope evolution indicates that the amount of size growth is constant with stellar mass. This suggests that galaxies in massive clusters such as SPT-CL J0546$-$5345 grow via processes that increase the size without significant morphological interference, such as minor mergers and/or adiabatic expansion. The slope of the cluster stellar mass - size relation is significantly shallower if measured in $HST$/ACS imaging at wavelengths blueward of the Balmer break, similar to rest-frame UV relations at $z$ = 1 in the literature. The stellar mass - size relation must be measured at redder wavelengths, which are more sensitive to the old stellar population that dominates the stellar mass of the galaxies. The slope is unchanged when GeMS $K_s$-band imaging is degraded to the resolution of $K$-band HST/NICMOS resolution but dramatically affected when degraded to $K_s$-band Magellan/FourStar resolution. Such measurements must be made with AO in order to accurately characterise the sizes of compact, $z$ = 1 galaxies.Comment: 24 pages, 13 figures, 3 tables. Accepted for publication in MNRAS. Typos corrected, DOI adde

Synchronized Artificial Natures: The Secret Life of Trees Connecting York, Delft and Alicante

This paper presents an experiment that explored teaching limits in architecture and computational arts. Three universities (York, Tu-Delft and Alicante) collaborated, commissioning and producing three Interactive scenographic spaces. These were formed by visitors, artificial trees as well as reactive technologies and emulated the way in which fungi communicate by connecting their roots underground. Over the four months of duration of the experiment, students learnt about programming resources in contemporary musical scenographic creation; graphic resources and digital manufacturing for 3D printing; component design; Arduino programming; and interfaces such as the “Game of Life” to explain the project in terms of cooperating particles. Theoretical backgrounds such as the architecture of contingency, readings such as “the secret life of the trees” by Wohlleben and performance practices such as “A-volve” by Mignonneau and Sommerer or “Hylozoic series” by Philip Beesley were approached in the workshop. The ultimate goals of this teaching practice described more explicitly in the paper include: understanding the ways in which communities cooperate; synchronous communication between scenic spaces as well as transparent design processes; and efforts to reduce excessive subject learning encapsulation in new Degrees based on the Bologna model

Bulk and single-molecule analysis of a bacterial DNA2-like helicase-nuclease reveals a single-stranded DNA looping motor

DNA2 is an essential enzyme involved in DNA replication and repair in eukaryotes. In a search for homologues of this protein, we identified and characterised Geobacillus stearothermophilus Bad, a bacterial DNA helicase-nuclease with similarity to human DNA2. We show that Bad contains an Fe-S cluster and identify four cysteine residues that are likely to co-ordinate the cluster by analogy to DNA2. The purified enzyme specifically recognises ss-dsDNA junctions and possesses ssDNA-dependent ATPase, ssDNA binding, ssDNA endonuclease, 5' to 3' ssDNA translocase and 5' to 3' helicase activity. Single molecule analysis reveals that Bad is a processive DNA motor capable of moving along DNA for distances of >4 kb at a rate of ∼200 bp per second at room temperature. Interestingly, as reported for the homologous human and yeast DNA2 proteins, the DNA unwinding activity of Bad is cryptic and can be unmasked by inactivating the intrinsic nuclease activity. Strikingly, our experiments show that the enzyme loops DNA while translocating, which is an emerging feature of processive DNA unwinding enzymes. The bacterial Bad enzymes will provide an excellent model system for understanding the biochemical properties of DNA2-like helicase-nucleases and DNA looping motor proteins in general.Wellcome Trust [100401/Z/12/Z to M.D.]; EuropeanResearch Council [681299 to F.M.-H.]; Spanish Min-istry of Economy and Competitiveness [BFU2017-83794-PAEI/FEDER, UE to F.M.-H.]; Comunidad de MadridTec4Bio [S2018/NMT-4443 to F.M.-H.]; NanoBioCancer[Y2018/BIO-4747 to F.M.-H.]. Funding for open accesscharge: Wellcome Trust [100401/Z/12/Z].Peer reviewe

Justicia del agua transfronteriza: una lectura combinada de la literatura crítica sobre la interacción del agua transfronteriza y la ‘justicia’, para el análisis y la diplomacia

Mediante la revisión y combinación de dos grandes cuerpos de investigación —el trabajo crítico sobre la interacción del agua transfronteriza y siglos de pensamiento sobre justicia social— este artículo busca contribuir a la diplomacia y al análisis internacional sobre la interacción del agua transfronteriza. Varias implicaciones para el análisis y la diplomacia transfronteriza suelen relacionarse con cuestiones de equidad, preocupaciones estructurales, y procesos y resultados. Esto incluye deficiencias en los análisis y las políticas basadas en presunciones infundadas de igualdad, así como en opciones que no son consideradas debido a la legitimación de unos conceptos particulares de justicia sobre otros. Debido a que se considera que la asimetría de poder permite o impide esfuerzos relacionados con la resolución de conflictos y la demanda de justicia, se defiende la importancia de garantizar resultados equitativos como prerrequisito para la cooperación. De manera similar, al menos procesualmente, la resolución de conflictos hídricos suele ser vista como más justa que la gestión del conflicto, por lo que, hasta cierto punto, puede estar respaldada por la legislación internacional del agua. Se sugieren una serie de objetivos analíticos para futuras investigaciones y políticas, entre las cuales se incluye un llamado a examinar la fuente de legitimidad de las vertientes de justicia invocadas. Dadas las múltiples perspectivas de justicia que existen en la red de actores relevantes, el potencial sesgo en la investigación y la diplomacia podría reducirse si todos los involucrados reconocieran públicamente los valores morales que sustentan su comprensión de “justicia”

Justicia del agua transfronteriza: una lectura combinada de la literatura crítica sobre la interacción del agua transfronteriza y la ‘justicia’, para el análisis y la diplomacia

By reviewing and blending two main bodies of research (critical transboundary water interaction analysis and centuries of thought on social justice) this paper seeks to improve international transboundary water interaction analysis and diplomacy. Various implications for transboundary analysis and diplomacy are grouped under themes of equitability, process/outcomes, and structural concerns. These include shortcomings of analysis and policy based on unfounded assumptions of equality, and options excluded from consideration by the legitimisation of particular concepts of justice over others. As power asymmetry is seen to enable or disable justice claims and conflict resolution efforts, the importance of ensuring equitable outcomes as a pre condition for cooperation is asserted. Similarly, water conflict resolution is found to be more fair – procedurally – than is conflict management, and may be supported to a limited extent by international water law. A number of analytical tasks are suggested for future research and policy, including a call to scrutinise the source of legitimacy of strands of justice invoked. Given the very many perspectives on justice that exist in the network of relevant actors, potential bias in research and diplomacy could be reduced if all involved openly stated the morals underpinning their understanding of ‘justice’.Mediante la revisión y combinación de dos grandes cuerpos de investigación —el trabajo crítico sobre la interacción del agua transfronteriza y siglos de pensamiento sobre justicia social— este artículo busca contribuir a la diplomacia y al análisis internacional sobre la interacción del agua transfronteriza. Varias implicaciones para el análisis y la diplomacia transfronteriza suelen relacionarse con cuestiones de equidad, preocupaciones estructurales, y procesos y resultados. Esto incluye deficiencias en los análisis y las políticas basadas en presunciones infundadas de igualdad, así como en opciones que no son consideradas debido a la legitimación de unos conceptos particulares de justicia sobre otros. Debido a que se considera que la asimetría de poder permite o impide esfuerzos relacionados con la resolución de conflictos y la demanda de justicia, se defiende la importancia de garantizar resultados equitativos como prerrequisito para la cooperación. De manera similar, al menos procesualmente, la resolución de conflictos hídricos suele ser vista como más justa que la gestión del conflicto, por lo que, hasta cierto punto, puede estar respaldada por la legislación internacional del agua. Se sugieren una serie de objetivos analíticos para futuras investigaciones y políticas, entre las cuales se incluye un llamado a examinar la fuente de legitimidad de las vertientes de justicia invocadas. Dadas las múltiples perspectivas de justicia que existen en la red de actores relevantes, el potencial sesgo en la investigación y la diplomacia podría reducirse si todos los involucrados reconocieran públicamente los valores morales que sustentan su comprensión de “justicia”

El riesgo y crecimiento económico en el sector textil de Lima Metropolitana hacia los mercados emergentes periodo 2019 – 2022

La presente investigación titulada “El Riesgo y Crecimiento económico en el Sector Textil de Lima Metropolitana hacia los Mercados Emergentes periodo 2019-2022”. Tiene como objetivo Determinar el impacto del riesgo en base al crecimiento económico en el Sector Textil de Lima Metropolitana hacia los mercados emergentes periodo 2019-2022. La metodología es de tipo aplicada, con diseño no experimental y nivel longitudinal de tipo tendencia con enfoque cuantitativo. La técnica utilizada fue el análisis documental, como instrumento la ficha de recolección de datos estadísticos de fuentes secundarias relevantes de nuestras variables. Como resultado tuvo un grado de incidencia entre el riesgo y crecimiento económico en 0.5708, equivalente a 57.08%, puesto que el coeficiente se interpretó dentro del rango 0 y 1. Por lo que, el Crecimiento Económico estuvo en función al Riesgo en base al resultado del R2, implicando la aprobación de la hipótesis alterna que fue mayor al 50%. Concluyendo esta investigación, existe una correlación positiva entre el riesgo y crecimiento económico en el Sector Textil de Lima Metropolitana hacia los mercados emergentes periodo 2019-2022. Resultando un R²= 0.5708, representando más del 50% de los datos mostrados son significativos

Chi hotspots trigger a conformational change in the helicase-like domain of AddAB to activate homologous recombination

In bacteria, the repair of double-stranded DNA breaks is modulated by Chi sequences. These are recognised by helicase-nuclease complexes that process DNA ends for homologous recombination. Chi activates recombination by changing the biochemical properties of the helicase-nuclease, transforming it from a destructive exonuclease into a recombination-promoting repair enzyme. This transition is thought to be controlled by the Chi-dependent opening of a molecular latch, which enables part of the DNA substrate to evade degradation beyond Chi. Here, we show that disruption of the latch improves Chi recognition efficiency and stabilizes the interaction of AddAB with Chi, even in mutants that are impaired for Chi binding. Chi recognition elicits a structural change in AddAB that maps to a region of AddB which resembles a helicase domain, and which harbours both the Chi recognition locus and the latch. Mutation of the latch potentiates the change and moderately reduces the duration of a translocation pause at Chi. However, this mutant displays properties of Chi-modified AddAB even in the complete absence of bona fide hotspot sequences. The results are used to develop a model for AddAB regulation in which allosteric communication between Chi binding and latch opening ensures quality control during recombination hotspot recognition