Influencia de mallas sombreadoras sobre características morfológicas, fisiológicas y productivas de Vaccinium corymbosum L. (CV. Elliott).

49 p.Ensayos previos de nuestro grupo han mostrado que las mallas sombreadoras pueden aumentar rendimiento en arándanos, pero se requiere más información respecto a su impacto sobre las variables fotosintéticas de este cultivo. Plantas de arándano de arbusto alto cv. Elliott (7 años de edad, con un marco de plantación de 3 x 1 m) fueron cultivadas en un suelo franco arenoso correspondiente a un huerto comercial de la Sociedad Agrícola y Ganadera Río Cato (km. 20 camino Tres esquinas, provincia de Ñuble, VIII región. 36º 32´ 33” S; 71º 47´38” O). Sobre las plantas se dispusieron mallas sombreadoras de diferentes colores (blancas, rojas y negras; más un sector sin mallas que se utilizó como tratamiento control), y densidades de tramado (25%, 50% y 70% de sombra). Los tratamientos fueron asignados aleatoriamente con 3 repeticiones por tratamiento, y 6 plantas por repetición. El ensayo se llevó a cabo por dos temporadas sucesivas (2006-2007 y 2007-2008). En cada temporada, las mallas permanecieron puestas sobre las plantas a una altura de 3 m. sobre el nivel del suelo, desde octubre a abril del año siguiente. Los mayores niveles de actividad fotosintética (Amax) y puntos de saturación se registraron en hojas expuestas a pleno sol, los que fueron estadísticamente superiores que hojas sombreadas. La tasa fotosintética bajo mallas a condiciones de luz ambiente se redujo linealmente con el sombreamiento. El color de malla también afectó la tasa de asimilación foliar de CO2, siendo las mallas negras las que lograron niveles superiores de fotosíntesis en la hoja. A diferencia de lo esperado, el contenido de clorofilas (a, b, total y relación clorofila a/b), no se vio afectado significativamente con una reducción de la radiación. Valores de Fv/Fm luego de las 15:00 h. descendieron linealmente con la reducción en los niveles de RFA incidente. Hojas de plantas testigo presentaron a las 15:00 y 18:00 h, valores de Fv/Fm inferiores a 0.8, rango indicado como índice de estrés. Una reducción en la RFA disminuyó el rendimiento por planta, independiente del color de malla. El peso del fruto aumentó como efecto del uso de mallas; así, mallas negro 25% tuvieron peso de frutos significativamente mayores. Frutos bajo mallas negras y rojas mostraron el mayor calibre ecuatorial de fruto. Los sólidos solubles aumentaron proporcionalmente con la intensidad de la radiación. Frutos provenientes de plantas con mayor nivel de sombreamiento presentaron mayor firmeza de fruto a cosecha./ABSTRACT: Previous experiments have shown that shading nets can increase yields in blueberries, but more information is needed regarding the effect of shading nets on photosynthetic performance of this crop. Seven-year-old `Elliott´ highbush blueberry plants established at 3 x 1 m grown in a sandy loam soil of a commercial field belonging to “Sociedad Agrícola y Ganadera Río Cato” (km 20 road to Tres Esquinas), Ñuble Province, VIII region, 36º 32´ 33" S; 71° 47´ 38" W) were used for this experiment. Colored shading nets (white, red and black) of different shading levels (25%, 50% and 70% shade) were placed over the plants at 3m height. A control treatment (no shade) was included. Treatments were assigned randomly with 3 replicates per treatment, and 6 plants per replication. The trial was carried out for two successive seasons (2006-2007 and 2007-2008). In each season, nets remained over the plants from October to April of the following year. The highest photosynthetic activities (Amax) were recorded in leaves exposed to full sun. Amax and saturation values were statistically higher in fully exposed leaves (control). Under ambient light conditions the photosynthetic rate was linearly reduced as shading increased. The color of nets also affected leaf CO2 assimilation rate, with black nets achieving higher photosynthetic levels. Contrary to expected, chlorophyll contents (a, b, total and chlorophyll a/b ratio), in contrast to expectations, was not significantly affected by radiation levels. Fv/Fm declined linearly after 15:00 h with the reduction in incident PAR. Between 15:00 and 18:00 h, leaves of control plants had Fv/Fm values lower than 0.8, which is a range indicative of stress. Reductions in PAR decreased yield per plant, independent of net color. Fruit weight was higher under nets, with black net of 25% shade having significantly higher fruit weight. Soluble solids increased proportionately with radiation intensity. Shading increased fruit firmness at harvest. Fruit under red and black nets had higher fruit equatorial diameter

Estudio del potencial de acumulación de metales pesados de plantas nativas peruanas para la fitorremediación de pasivos mineros

Las actividades mineras tienen una gran participación en la economía del país, y su presencia en diferentes regiones es histórica. Sin embargo, el impacto generado por minas abandonadas o el mal manejo de relaves han generado pasivos ambientales mineros (PAM), los cuales pueden producir un impacto en el medioambiente. En la búsqueda de soluciones sostenibles a largo plazo y más económicas que las usadas por la industria, la Fitorremediación se presenta como una alternativa investigada ampliamente en otros países, ya que permite hacer uso de especies vegetales para la acumulación de metales pesados. Es por ello que el presente trabajo tiene como objetivo analizar el potencial de plantas nativas como el Ichu y Cortadera, para la absorción de metales pesados de PAM. Para tal fin, se recolectan muestras de estas especies y de suelos de zonas específicas de la provincia de Hualgayoc, Cajamarca. A partir de eso, se construyen celdas a escala de laboratorio, en donde se siembran las plantas sobre las muestras de suelo. Una vez terminado el ciclo de 8 meses, se procede a retirar las especies y determinar las concentraciones finales de los metales pesados en la raíz y en las partes aéreas de la planta. En base a la información recopilada y al análisis realizado se concluye que las plantas presentan diferentes capacidades de acumulación de metales, siendo el Fe el que presenta la mayor absorción, seguido principalmente por el Cu y Zn, y en menor cantidad el Cd, Pb y Cr. De igual manera, se determina que la eficiencia de la remoción se incrementa cuando las plantas se exponen a suelos con pH menores a 7, a pesar de que la capacidad de absorción en las partes aéreas disminuye. En general, se aprecia que las plantas nativas son propicias para continuar con más investigaciones y con un proceso de Fitorremediación de PAM a mayor escala

Long-term follow-up observations of extreme coronal line emitting galaxies

We present new spectroscopic and photometric follow-up observations of the known sample of extreme coronal line emitting galaxies (ECLEs) identified in the Sloan Digital Sky Survey (SDSS). With these new data, observations of the ECLE sample now span a period of two decades following their initial SDSS detections. We confirm the nonrecurrence of the iron coronal line signatures in five of the seven objects, further supporting their identification as the transient light echoes of tidal disruption events (TDEs). Photometric observations of these objects in optical bands show little overall evolution. In contrast, mid-infrared (MIR) observations show ongoing long-term declines. The remaining two objects had been classified as active galactic nuclei (AGN) with unusually strong coronal lines rather than being TDE related, given the persistence of the coronal lines in earlier follow-up spectra. We confirm this classification, with our spectra continuing to show the presence of strong, unchanged coronal-line features and AGN-like MIR colours and behaviour. We have constructed spectral templates of both subtypes of ECLE to aid in distinguishing the likely origin of newly discovered ECLEs. We highlight the need for higher cadence, and more rapid, follow-up observations of such objects to better constrain their properties and evolution. We also discuss the relationships between ECLEs, TDEs, and other identified transients having significant MIR variability.Comment: Submitted to MNRAS. 33 pages, 15 figure

Long-term follow-up observations of extreme coronal line emitting galaxies

We present new spectroscopic and photometric follow-up observations of the known sample of extreme coronal line-emitting galaxies (ECLEs) identified in the Sloan Digital Sky Survey (SDSS). With these new data, observations of the ECLE sample now span a period of two decades following their initial SDSS detections. We confirm the non-recurrence of the iron coronal line signatures in five of the seven objects, further supporting their identification as the transient light echoes of tidal disruption events (TDEs). Photometric observations of these objects in optical bands show little overall evolution. In contrast, mid-infrared (MIR) observations show ongoing long-term declines consistent with power-law decay. The remaining two objects had been classified as active galactic nuclei (AGNs) with unusually strong coronal lines rather than being TDE related, given the persistence of the coronal lines in earlier follow-up spectra. We confirm this classification, with our spectra continuing to show the presence of strong, unchanged coronal line features and AGN-like MIR colours and behaviour. We have constructed spectral templates of both subtypes of ECLE to aid in distinguishing the likely origin of newly discovered ECLEs. We highlight the need for higher cadence, and more rapid, follow-up observations of such objects to better constrain their properties and evolution. We also discuss the relationships between ECLEs, TDEs, and other identified transients having significant MIR variability

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (μ̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ¯ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ¯ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),μ̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| &lt; 0.03 at 95% confidence level. [Figure not available: see fulltext.

The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease

Measurement of the Splitting Function in &ITpp &ITand Pb-Pb Collisions at root&ITsNN&IT=5.02 TeV

Data from heavy ion collisions suggest that the evolution of a parton shower is modified by interactions with the color charges in the dense partonic medium created in these collisions, but it is not known where in the shower evolution the modifications occur. The momentum ratio of the two leading partons, resolved as subjets, provides information about the parton shower evolution. This substructure observable, known as the splitting function, reflects the process of a parton splitting into two other partons and has been measured for jets with transverse momentum between 140 and 500 GeV, in pp and PbPb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. In central PbPb collisions, the splitting function indicates a more unbalanced momentum ratio, compared to peripheral PbPb and pp collisions.. The measurements are compared to various predictions from event generators and analytical calculations.Peer reviewe

Observation of the Production of Three Massive Gauge Bosons at root s=13 TeV

The first observation is reported of the combined production of three massive gauge bosons (VVV with V = W, Z) in proton-proton collisions at a center-of-mass energy of 13 TeV. The analysis is based on a data sample recorded by the CMS experiment at the CERN LHC corresponding to an integrated luminosity of 137 fb(-1). The searches for individualWWW, WWZ, WZZ, and ZZZ production are performed in final states with three, four, five, and six leptons (electrons or muons), or with two same-sign leptons plus one or two jets. The observed (expected) significance of the combinedVVV production signal is 5.7 (5.9) standard deviations and the corresponding measured cross section relative to the standard model prediction is 1.02(-0.23)(+0.26). The significances of the individual WWW and WWZ production are 3.3 and 3.4 standard deviations, respectively. Measured production cross sections for the individual triboson processes are also reported