Explore the vast range of titles available.

Studies involving retrograde orbits have been an emerging field in recent years, particularly in the case where there are resonances between objects orbiting in opposite directions. The high amount of data from space exploration missions increases the possibility of observing binary stellar systems which may have additional bodies with retrograde orbits. Furthermore, such orbits are relevant to understanding the dynamics of spacecrafts around binary asteroids, being essential to planning exploratory missions. In this work, we survey retrograde orbits around binary systems with mass ratio between 0.01 (hierarchical) and 0.5 (equal masses) in the framework of the planar circular restricted three-body problem (PCR3BP). We build surfaces of section and identify retrograde resonances up to fifth order, namely the 2/−1, 3/−2, 1/−1, 2/−3, 1/−2, 1/−3 and 1/−4 resonances. We conclude that retrograde resonances occur in binary systems at high mass ratio, including the co-orbital (1/−1) resonance. Period doubling bifurcations occur for the 1/−1 resonance, and period doubling and period tripling bifurcations are observed for the 1/−2 resonance. Asymmetric retrograde resonances of the type 1/−n occur for almost equal masses of the binary system. This study may be used for identifying retrograde planets in extrasolar systems and may possibly have applications to astrodynamics mission planning.

The study of resonances in celestial mechanics is crucial for understanding the dynamics of planetary or stellar systems. This study focuses on presenting a method for investigating the topology and resonant structures of a dynamical system. To illustrate the strength of the method, we have applied our method to retrograde resonances in the planar circular restricted three-body problem within binary star systems. Because of the high mass ratio systems, the techniques based on perturbation of the two-body orbit are not the ideal to analyze the system. Consequently, resonant angles could be meaningless, necessitating alternative methods for resonance identification. To address this challenge, an image classification-based machine learning model is implemented to identify resonances based on the shape of orbits in the rotating frame. Initially, the model is trained on empirical cases with low mass ratios using the resonant angle as a starting point for resonance identification. The model’s performance is validated against existing literature results. The model results demonstrate successful classification and identification of retrograde resonances in both empirical and non-empirical cases. The model accurately captures the resonance patterns and provides initial insights into the short-term stability of the corresponding resonances.

The natural satellite of Jupiter, Io, is one of the most interesting bodies in the solar system and deserves to be studied in detail. Up to now, no man-made vehicle has orbited Io because the level of radiation is too high for an orbiter to stay nearby for longer periods of time. In that sense, only flyby missions have studied this body. With the advance of technology, an important step in Solar System research is to develop shields that are strong enough to make orbiter missions around Io possible in the near future. With that in mind, the present paper has the goal, as first step, of mapping possible stable orbits around Io that can accommodate a spacecraft and that do not require station-keeping maneuvers to survive. The dynamical system considers the gravity fields of the Sun, Jupiter, Saturn, Europa, Ganymede, Callisto and the non-spherical shape of Jupiter and Io. To help in this search and to better explain the reasons of stability, integral indices are used to map the less perturbed orbits to guide the numerical searches for stable orbits. We observe several regions of bounded orbits around Io. In these orbits, a relation between the perturbation indices and the duration of stability is found, demonstrating the importance of this tool in mission analyses. Several regions of bounded orbits are found in this system.

We present a numerical study on the stability of the 1/2, 2/1 and 1/1 retrograde mean motion resonances in the 3-body problem composed of a solar mass star, a Jupiter mass planet and an additional body with zero mass (elliptic restricted 3-body problem) or masses corresponding to either Neptune, Saturn or Jupiter (planetary 3-body problem). For each system we obtain stability maps using the n-body numerical integrator REBOUND and computing the chaos indicator mean exponential growth factor of nearby orbits (MEGNO). We show that families of periodic orbits exist in all configurations and they correspond to the libration of either a single resonant argument or all resonant arguments (fixed points). We compare the results obtained in the elliptic restricted 3-body problem with previous results in the literature and we show the differences and similarities between the phase space topology for these retrograde resonances in the circular restricted, elliptic restricted and planetary 3-body problems.

In this contribution we characterize the spatial diversity of bird populations in a heterogeneous landscape with respect to vegetation in the northern Pantanal region of Brazil. The method of additive partitioning of species diversity (γ = α + β) was used. Samples were collected in a grid with 30 sampling plots within a 25 km² area (5 x 5 km). A total of 163 bird species were found, comprising 114 resident species and 49 regional migrants. Most species were restricted spatially, with 58% found in a maximum of five sampling plots, while 15% were found in only one plot. The beta diversity comprised 77% of total diversity and was lower for residents than for regional migrants (66% and 88%, respectively). This suggests greater spatial heterogeneity in diversity patterns for regional migrants. Seasonal availability of resources caused by changing water levels as well as anthropogenic influences may also play a role in species diversity patterns by influencing species composition across sampling plots. High beta diversity and species-specific habitat occupancy suggest that conservation and management strategies should be implemented at a regional spatial scale and focus on the conservation of this environmental mosaic.

Suppression of transposable elements (TEs) is paramount to maintain genomic integrity and organismal fitness. In D . melanogaster , the flamenco locus is a master suppressor of TEs, preventing the mobilization of certain endogenous retrovirus-like TEs from somatic ovarian support cells to the germline. It is transcribed by Pol II as a long (100s of kb), single-stranded, primary transcript, and metabolized into ~24–32 nt Piwi-interacting RNAs (piRNAs) that target active TEs via antisense complementarity. flamenco is thought to operate as a trap, owing to its high content of recent horizontally transferred TEs that are enriched in antisense orientation. Using newly-generated long read genome data, which is critical for accurate assembly of repetitive sequences, we find that flamenco has undergone radical transformations in sequence content and even copy number across simulans clade Drosophilid species. Drosophila simulans flamenco has duplicated and diverged, and neither copy exhibits synteny with D . melanogaster beyond the core promoter. Moreover, flamenco organization is highly variable across D . simulans individuals. Next, we find that D . simulans and D . mauritiana flamenco display signatures of a dual-stranded cluster, with ping-pong signals in the testis and/or embryo. This is accompanied by increased copy numbers of germline TEs, consistent with these regions operating as functional dual-stranded clusters. Overall, the physical and functional diversity of flamenco orthologs is testament to the extremely dynamic consequences of TE arms races on genome organization, not only amongst highly related species, but even amongst individuals.

Estimates of influenza-associated mortality are important for national and international decision making on public health priorities. Previous estimates of 250 000–500 000 annual influenza deaths are outdated. We updated the estimated number of global annual influenza-associated respiratory deaths using country-specific influenza-associated excess respiratory mortality estimates from 1999–2015. We estimated country-specific influenza-associated respiratory excess mortality rates (EMR) for 33 countries using time series log-linear regression models with vital death records and influenza surveillance data. To extrapolate estimates to countries without data, we divided countries into three analytic divisions for three age groups (<65 years, 65–74 years, and ≥75 years) using WHO Global Health Estimate (GHE) respiratory infection mortality rates. We calculated mortality rate ratios (MRR) to account for differences in risk of influenza death across countries by comparing GHE respiratory infection mortality rates from countries without EMR estimates with those with estimates. To calculate death estimates for individual countries within each age-specific analytic division, we multiplied randomly selected mean annual EMRs by the country's MRR and population. Global 95% credible interval (CrI) estimates were obtained from the posterior distribution of the sum of country-specific estimates to represent the range of possible influenza-associated deaths in a season or year. We calculated influenza-associated deaths for children younger than 5 years for 92 countries with high rates of mortality due to respiratory infection using the same methods. EMR-contributing countries represented 57% of the global population. The estimated mean annual influenza-associated respiratory EMR ranged from 0·1 to 6·4 per 100 000 individuals for people younger than 65 years, 2·9 to 44·0 per 100 000 individuals for people aged between 65 and 74 years, and 17·9 to 223·5 per 100 000 for people older than 75 years. We estimated that 291 243–645 832 seasonal influenza-associated respiratory deaths (4·0–8·8 per 100 000 individuals) occur annually. The highest mortality rates were estimated in sub-Saharan Africa (2·8–16·5 per 100 000 individuals), southeast Asia (3·5–9·2 per 100 000 individuals), and among people aged 75 years or older (51·3–99·4 per 100 000 individuals). For 92 countries, we estimated that among children younger than 5 years, 9243–105 690 influenza-associated respiratory deaths occur annually. These global influenza-associated respiratory mortality estimates are higher than previously reported, suggesting that previous estimates might have underestimated disease burden. The contribution of non-respiratory causes of death to global influenza-associated mortality should be investigated. None.

Among the main greenhouse gases (CO2, CH4 and N2O), N2O has the highest global warming potential. N2O emission is mainly connected to agricultural activities, increasing as nitrogen concentrations increase in the soil with nitrogen fertilizer application. We evaluated N2O emissions due to application of increasing doses of ammonium nitrate and urea in two sugarcane fields in the mid-southern region of Brazil: Piracicaba (São Paulo state) and Goianésia (Goiás state). In Piracicaba, N2O emissions exponentially increased with increasing N doses and were similar for urea and ammonium nitrate up to a dose of 107.9 kg ha−1 of N. From there on, emissions exponentially increased for ammonium nitrate, whereas for urea they stabilized. In Goianésia, N2O emissions were lower, although the behavior was similar to that at the Piracicaba site. Ammonium nitrate emissions increased linearly with N dose and urea emissions were adjusted to a quadratic equation with a maximum amount of 113.9 kg N ha−1. This first effort to measure fertilizer induced emissions in Brazilian sugarcane production not only helps to elucidate the behavior of N2O emissions promoted by different N sources frequently used in Brazilian sugarcane fields but also can be useful for future Brazilian ethanol carbon footprint studies.

Europe imports large amounts of soybean that are predominantly used for livestock feed, mainly sourced from Brazil, USA and Argentina. In addition, the demand for GM-free soybean for human consumption is project to increase. Soybean has higher protein quality and digestibility than other legumes, along with high concentrations of isoflavones, phytosterols and minerals that enhance the nutritional value as a human food ingredient. Here, we examine the potential to increase soybean production across Europe for livestock feed and direct human consumption, and review possible effects on the environment and human health. Simulations and field data indicate rainfed soybean yields of 3.1 ± 1.2 t ha −1 from southern UK through to southern Europe (compared to a 3.5 t ha −1 average from North America). Drought-prone southern regions and cooler northern regions require breeding to incorporate stress-tolerance traits. Literature synthesized in this work evidenced soybean properties important to human nutrition, health, and traits related to food processing compared to alternative protein sources. While acknowledging the uncertainties inherent in any modelling exercise, our findings suggest that further integrating soybean into European agriculture could reduce GHG emissions by 37–291 Mt CO 2e year −1 and fertiliser N use by 0.6–1.2 Mt year −1 , concurrently improving human health and nutrition.

We utilized a proteomic approach to investigate seed development in Medicago truncatula, cv Jemalong, line J5 at specific stages of seed filling corresponding to the acquisition of germination capacity and protein deposition. One hundred twenty proteins differing in kinetics of appearance were subjected to matrix-assisted laser desorption ionization time of flight mass spectrometry. These analyses provided peptide mass fingerprint data that identified 84 of them. Some of these proteins had previously been shown to accumulate during seed development in legumes (e.g. legumins, vicilins, convicilins, and lipoxygenases), confirming the validity of M. truncatula as a model for analysis of legume seed filling. The study also revealed proteins presumably involved in cell division during embryogenesis (beta-tubulin and annexin). Their abundance decreased before the accumulation of the major storage protein families, which itself occurs in a specific temporal order: vicilins (14 d after pollination [DAP]), legumins (16 DAP), and convicilins (18 DAP). Furthermore, the study showed an accumulation of enzymes of carbon metabolism (e.g. sucrose synthase, starch synthase) and of proteins involved in embryonic photosynthesis (e.g. chlorophyll a/b binding), which may play a role in providing cofactors for protein/lipid synthesis or for CO2 refixation during seed filling. Correlated with the reserve deposition phase was the accumulation of proteins associated with cell expansion (actin 7 and reversibly glycosylated polypeptide) and of components of the precursor accumulating vesicles, which give rise to a trypsin inhibitor on maturation. Finally, we revealed a differential accumulation of enzymes involved in methionine metabolism (S-adenosyl-methionine synthetase and S-adenosylhomo-cysteine hydrolase) and propose a role for these enzymes in the transition from a highly active to a quiescent state during seed development.