Abstract
We present the first version of the Automatic Learning for the Rapid Classification of Events (ALeRCE) broker light curve classifier. ALeRCE is currently processing the Zwicky Transient ...Facility (ZTF) alert stream, in preparation for the Vera C. Rubin Observatory. The ALeRCE light curve classifier uses variability features computed from the ZTF alert stream and colors obtained from AllWISE and ZTF photometry. We apply a balanced random forest algorithm with a two-level scheme where the top level classifies each source as periodic, stochastic, or transient, and the bottom level further resolves each of these hierarchical classes among 15 total classes. This classifier corresponds to the first attempt to classify multiple classes of stochastic variables (including core- and host-dominated active galactic nuclei, blazars, young stellar objects, and cataclysmic variables) in addition to different classes of periodic and transient sources, using real data. We created a labeled set using various public catalogs (such as the Catalina Surveys and Gaia DR2 variable stars catalogs, and the Million Quasars catalog), and we classify all objects with ≥6
g
-band or ≥6
r
-band detections in ZTF (868,371 sources as of 2020 June 9), providing updated classifications for sources with new alerts every day. For the top level we obtain macro-averaged precision and recall scores of 0.96 and 0.99, respectively, and for the bottom level we obtain macro-averaged precision and recall scores of 0.57 and 0.76, respectively. Updated classifications from the light curve classifier can be found at the ALeRCE Explorer website (
http://alerce.online
).
Theories attempting to explain species coexistence in plant communities have argued in favour of species' capacities to occupy a multidimensional niche with spatial, temporal and biotic axes. We used ...the concept of hydrological niche segregation to learn how ecological niches are structured both spatially and temporally and whether small scale humidity gradients between adjacent niches are the main factor explaining water partitioning among tree species in a highly water‐limited semiarid forest ecosystem. By combining geophysical methods, isotopic ecology, plant ecophysiology and anatomical measurements, we show how coexisting pine and oak species share, use and temporally switch between diverse spatially distinct niches by employing a set of functionally coupled plant traits in response to changing environmental signals. We identified four geospatial niches that turned into nine, when considering the temporal dynamics of the wetting/drying cycles in the substrate and the particular plant species adaptations to garner, transfer, store and use water. Under water scarcity, pine and oak exhibited water use segregation from different niches, yet under maximum drought when oak trees crossed physiological thresholds, niche overlap occurred. The identification of niches and mechanistic understanding of when and how species use them will help unify theories of plant coexistence and competition.
Pine and oak used anatomical, morphological and physiological traits to acquire spatially and temporally water availability. We identified up to nine spatial and temporal hydraulic niches that helped these forest species to reduce resource use overlapping and permit coexistence.
Abstract
This paper, of the network parity situation of photovoltaic solar energy with conventional electrical energy sources, such as hydroelectric and thermoelectric for Peru is analyzed. For this ...purpose, a review of how the electrical tariff is set for the residential end-user of conventional energy sources has been made. Furthermore, it is shown what it consists about, the cost leveled of energy for the case of photovoltaic solar energy and how this has been used for the calculation of the electric rate of this type of source. A review of the auctions of photovoltaic solar plants that are installed in: Moquegua, Tacna and Arequipa is carried out. The solar photovoltaic tariff has been obtained by auctions, between the year 2010 to 2016, these have decreased significantly until reaching network parity. The costs of both energy sources are compared.
It is well known that inherent characteristics of forest species constitute the main control of litter decomposition. In mixed forest, chemical interactions occurring through precipitation turn ...mechanisms of litter decomposition very uncertain and difficult to predict. Early-stage leaf litter decomposition of Quercus potosina and Pinus cembroides and their controls were examined based on Ostrofsky’s decomposition mechanisms. From June 2007 to May 2008, litterbags with pure and mixed leaf-litter of Q. potosina and P. cembroides were incubated in situ in monospecific and mixed tree stands, respectively. Sampling was carried out 3, 6, 9, and 12 months after incubation. After 12 months, two phases of decomposition of pure and mixed litter were identified; an early phase with a greater rate of mass loss of the labile litter fraction (k L ; soluble compounds) and a later phase with a lower rate of mass loss of the recalcitrant litter fraction (k R; lignin). The labile fraction lost was observed at three and 6 months of incubation, which coincided with the months of highest rainfall likely triggering a rapid release of soluble carbon compounds from leaf litter. Results also indicate that leaf-litter from Q. potosina had higher concentration of soluble compounds and lower lignin concentration than leaf litter from P. cembroides. Observed facilitative and inhibitory mechanisms for mass loss in Q. potosina and P. cembroides were controlled by interaction between physico-chemical litter characteristics and rainfall.
The study of proportional relationships between size, shape, and function of part of or the whole organism is traditionally known as allometry. Examination of correlative changes in the size of ...interbranch distances (IBDs) at different root orders may help to identify root branching rules. Root morphological and functional characteristics in three range grasses {bluebunch wheatgrass Pseudoroegneria spicata (Pursh) Löve, crested wheatgrass Agropyron desertorum (Fisch. ex Link) Schult.×A. cristatum (L.) Gaert., and cheatgrass (Bromus tectorum L.)} were examined in response to a soil nutrient gradient. Interbranch distances along the main root axis and the first-order laterals as well as other morphological and allocation root traits were determined. A model of nutrient diffusivity parameterized with root length and root diameter for the three grasses was used to estimate root functional properties (exploitation efficiency and exploitation potential). The results showed a significant negative allometric relationship between the main root axis and first-order lateral IBD (P ≤0.05), but only for bluebunch wheatgrass. The main root axis IBD was positively related to the number and length of roots, estimated exploitation efficiency of second-order roots, and specific root length, and was negatively related to estimated exploitation potential of first-order roots. Conversely, crested wheatgrass and cheatgrass, which rely mainly on root proliferation responses, exhibited fewer allometric relationships. Thus, the results suggested that species such as bluebunch wheatgrass, which display slow root growth and architectural root plasticity rather than opportunistic root proliferation and rapid growth, exhibit correlative allometry between the main axis IBD and morphological, allocation, and functional traits of roots.
Our objective was to describe the risk of hospital admission for virologically confirmed dengue (VCD) and the risk of clinically severe hospitalized VCD occurring up to 4 years after the first dose ...(years 1 to 4) in three randomized clinical trials comparing tetravalent dengue vaccine with placebo.
The relative risks (RR) for hospitalized VCD from first dose to year 4 were estimated by year and age-group in individual and combined studies.
Overall, from Year 1 to Year 4, 233 and 228 participants had at least one episode of hospitalized VCD in the vaccinated (n = 22 603) and placebo (n = 11 301) groups, respectively (RR = 0.511, 95% CI 0.42–0.62). Among these, 48 and 47 cases, respectively, were classified as clinically severe. In children aged ≥9 years, 88 and 136 participants had at least one episode of hospitalized VCD in the vaccinated (n = 17 629) and placebo (n = 8821) groups, respectively (RR = 0.324; 95% CI 0.24–0.43). In vaccinated participants aged <9 years, particularly in those aged 2–5 years, there were more hospitalized VCD cases compared with the control participants in Year 3 but not in Year 4. The overall RR in those aged <9 years for Year 1 to Year 4 was 0.786 (95% CI 0.60–1.03), with a higher protective effect in the 6–8 year olds than in the 2–5 year olds.
The overall benefit-risk remained positive in those aged ≥9 years up to year 4, although the protective effect was lower in years 3 and 4 than in years 1 and 2.
Trees growing on shallow rocky soils must have exceptional adaptations when underlying weathered bedrock has no deep fractures for water storage. Under semiarid conditions, hydrology of shallow soils ...is expected to decouple from plant hydrology, as soils dry out as a result of rapid evaporation and competition for water increases between coexisting tree species.
Gas exchange and plant–water relations were monitored for 15 months for Pinus cembroides and Quercus potosina tree species in a tropical semiarid forest growing on c. 20-cm-deep soils over impermeable volcanic bedrock.
Soil and leaf water potential maintained a relatively constant offset throughout the year in spite of high intra-annual fluctuations reaching up to 5 MPa. Thus, hydrology of shallow soils did not decouple from hydrology of trees even in the driest period. A combination of redistribution mechanisms of water stored in weathered bedrock and hypodermic flow accessible to oak provided the source of water supply to shallow soils, where most of the actively growing roots occurred.
This study demonstrates a unique geoecohydrological mechanism that maintains a tightly coupled hydrology between shallow rocky soils and trees, as well as species coexistence in this mixed forest, where oak facilitates water access to pine.
Abstract
The classic classification scheme for active galactic nuclei (AGNs) was recently challenged by the discovery of the so-called changing-state (changing-look) AGNs. The physical mechanism ...behind this phenomenon is still a matter of open debate and the samples are too small and of serendipitous nature to provide robust answers. In order to tackle this problem, we need to design methods that are able to detect AGNs right in the act of changing state. Here we present an anomaly-detection technique designed to identify AGN light curves with anomalous behaviors in massive data sets. The main aim of this technique is to identify CSAGN at different stages of the transition, but it can also be used for more general purposes, such as cleaning massive data sets for AGN variability analyses. We used light curves from the Zwicky Transient Facility data release 5 (ZTF DR5), containing a sample of 230,451 AGNs of different classes. The ZTF DR5 light curves were modeled with a Variational Recurrent Autoencoder (VRAE) architecture, that allowed us to obtain a set of attributes from the VRAE latent space that describes the general behavior of our sample. These attributes were then used as features for an Isolation Forest (IF) algorithm that is an anomaly detector for a “one class” kind of problem. We used the VRAE reconstruction errors and the IF anomaly score to select a sample of 8809 anomalies. These anomalies are dominated by bogus candidates, but we were able to identify 75 promising CSAGN candidates.
High-protein diets (HPDs) offer health benefits, such as weight management and improved metabolic profiles. The effects of HPD on cardiac arrhythmogenesis remain unclear. Atrial fibrillation (AF), ...the most common arrhythmia, is associated with inflammasome activation. The role of the Absent-in-Melanoma 2 (AIM2) inflammasome in AF pathogenesis remains unexplored. In this study, we discovered that HPD increased susceptibility to AF. To demonstrate the involvement of AIM2 signaling in the pathogenesis of HPD-induced AF, wildtype (WT) and
mice were fed normal-chow (NC) and HPD, respectively. Four weeks later, inflammasome activity was upregulated in the atria of WT-HPD mice, but not in the
-HPD mice. The increased AF vulnerability in WT-HPD mice was associated with abnormal sarcoplasmic reticulum (SR) Ca
-release events in atrial myocytes. HPD increased the cytoplasmic double-strand (ds) DNA level, causing AIM2 activation. Genetic inhibition of AIM2 in
mice reduced susceptibility to AF, cytoplasmic dsDNA level, mitochondrial ROS production, and abnormal SR Ca
-release in atrial myocytes. These data suggest that HPD creates a substrate conducive to AF development by activating the AIM2-inflammasome, which is associated with mitochondrial oxidative stress along with proarrhythmic SR Ca
-release. Our data imply that targeting the AIM2 inflammasome might constitute a novel anti-AF strategy in certain patient subpopulations.
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