We present the results of an optical light-curve survey of 114 Jovian Trojan asteroids conducted to determine the fraction of contact binaries. Sparse sampling was used to assess the photometric ...range of the asteroids, and those showing the largest ranges were targeted for detailed follow-up observations. This survey led to the discovery of two Trojan asteroids, (17365) and (29314), displaying large light-curve ranges (~1 mag) and long rotation periods (<2 rotations day-1) consistent with a contact binary nature. The optical light curves of both asteroids are well matched by Roche binary equilibrium models. Using these binary models, we find low densities of ~600 and 800 kg m-3, suggestive of porous interiors. The fraction of contact binaries is estimated to be between 6% and 10%, comparable to the fraction in the Kuiper Belt. The total binary fraction in the Trojan clouds (including both wide and close pairs) must be higher.
The planets of our solar system formed from a gas-dust disk. However, there are some properties of the solar system that are peculiar in this context. First, the cumulative mass of all objects beyond ...Neptune (trans-Neptunian objects TNOs) is only a fraction of what one would expect. Second, unlike the planets themselves, the TNOs do not orbit on coplanar, circular orbits around the Sun, but move mostly on inclined, eccentric orbits and are distributed in a complex way. This implies that some process restructured the outer solar system after its formation. However, some of the TNOs, referred to as Sednoids, move outside the zone of influence of the planets. Thus, external forces must have played an important part in the restructuring of the outer solar system. The study presented here shows that a close fly-by of a neighboring star can simultaneously lead to the observed lower mass density outside 30 au and excite the TNOs onto eccentric, inclined orbits, including the family of Sednoids. In the past it was estimated that such close fly-bys are rare during the relevant development stage. However, our numerical simulations show that such a scenario is much more likely than previously anticipated. A fly-by also naturally explains the puzzling fact that Neptune has a higher mass than Uranus. Our simulations suggest that many additional Sednoids at high inclinations still await discovery, perhaps including bodies like the postulated planet X.
We present the results of a search for the reactivation of active asteroid 176P/LINEAR during its 2011 perihelion passage using deep optical observations obtained before, during, and after that ...perihelion passage. Deep composite images of 176P constructed from data obtained between 2011 June and 2011 December show no visible signs of activity, while photometric measurements of the object during this period also show no significant brightness enhancements similar to that observed for 176P between 2005 November and 2005 December when it was previously observed to be active. An azimuthal search for dust emission likewise reveals no evidence for directed emission (i.e., a tail, as was previously observed for 176P), while a one-dimensional surface brightness profile analysis shows no indication of a spherically symmetric coma at any time in 2011. We conclude that 176P did not in fact exhibit activity in 2011, at least not on the level on which it exhibited activity in 2005, and suggest that this could be due to the devolatization or mantling of the active site responsible for its activity in 2005.
Cast Ni-Si-B alloys have the potential for high-temperature applications because of their high resistance to wear, impact, corrosion, and oxidation at elevated temperatures due to an appropriate ...balance of hard phases and austenite that ensures a good compromise between toughness and hardness. In this work, NiSi3B2 specimens, fabricated by the lost-wax casting process, were investigated. Given the complex multiphase cast microstructure, a differential scanning calorimeter (DSC-TGA) analysis was employed to characterize the reactions that occur during solidification and the resulting phases were characterized using scanning electron microscopy (SEM), with energy-dispersive microanalysis (EDS) and backscattered electron (BSE) image and X-ray diffraction (XRD). Due to the presence of hard phases, machining of the Ni-Si-B components can pose additional difficulties. Therefore, the conditions of the solution heat treatment, which might lead to the homogenization of the microstructure, consequently improving its machinability, were also investigated. The results of the heat-treated samples indicated that the dissolution of the eutectic constituent is accompanied by a significant decrease in the hardness (approximately 17%). It is important to emphasize that the solution heat treatments carried out reduced the hardness without affecting the percentage of borides, which will allow improving the machinability without adversely affecting the alloy performance in service.
We present time-resolved near-infrared (J and H) photometry of the extreme Kuiper belt object (136108) Haumea (formerly 2003 EL61) taken to further investigate rotational variability of this object. ...The new data show that the near-infrared peak-to-peak photometric range is similar to the value at visible wavelengths, mR = 0.30 ± 0.02 mag. Detailed analysis of the new and previous data reveals subtle visible/near-infrared color variations across the surface of Haumea. The color variations are spatially correlated with a previously identified surface region, redder in B - R and darker than the mean surface. Our photometry indicates that the J - H colors of Haumea (J - H = -0.057 ± 0.016 mag) and its brightest satellite Hi'iaka (J - H = -0.399 ± 0.034 mag) are significantly (greater than 9s) different. The satellite Hi'iaka is unusually blue in J - H, consistent with strong 1.5 mm water-ice absorption. The phase coefficient of Haumea is found to increase monotonically with wavelength in the range 0.4 < l < 1.3. We compare our findings with other solar system objects and discuss implications regarding the surface of Haumea.
Assessment of marine debris ingestion by sea turtles is important, especially to ensure their survival. From January to December 2011, 23 specimens of five species of sea turtles were found dead or ...dying after being rehabilitated, along the coast of the municipality of Rio de Janeiro, Brazil. To detect the presence of marine debris in the digestive tract of these turtles, we conducted a postmortem examination from the esophagus until the distal portion of the large intestine for each specimen. Of the total number of turtles, 39% had ingested marine debris such as soft plastic, hard plastic, metal, polyethylene terephthalate (PET) bottle caps, human hair, tampons, and latex condoms. Five of the seven sea turtles species are found along the Brazilian coast, where they feed and breed. A large number of animals are exposed to various kinds of threats, including debris ingestion.
•Were examined 23 specimens of five different species.•There were found marine debris such as plastic, metal, PET bottle caps, human hair, tampons, and latex condoms.•Of all specimens that had eaten marine debris, 89% were of the species Chelonia mydas.•We believe the waste consumption can be the main cause of mortality of a huge number of sea turtles in Brazil.
Pseudohermaphroditism is an anomaly in the development of the reproductive system, and scarcely reported in Veterinary Medicine. Its etiology is not well elucidated, but studies show that it can be ...congenital or hereditary. Animals that have this condition have distinct phenotypic characteristics of their gonadal tissue. The study reports a bitch with no defined breed, nine months old and without a history of estrus, who presents external female genitalia and a penis in the vaginal canal. The patient was referred for ultrasound examination, which found the presence of testicles in subcutaneous and intrabdominal topography, without evidence of a uterus or ovaries. The patient was referred for exploratory laparotomy, orchiectomy and penectomy. Based on the phenotypic, sonographic and histological characteristics, it is concluded that this is a dog with male pseudohermaphroditism.
O pseudo-hermafroditismo é uma anomalia no desenvolvimento do sistema reprodutor pouco relatada na medicina veterinária. Sua etiologia não é bem elucidada, podendo ser congênita ou hereditária, onde os animais com essa condição apresentam características fenotípicas distintas de seu tecido gonadal. O estudo relata o caso de uma cadela sem raça definida, nove meses de idade, sem histórico de cio, apresentando genitália externa de fêmea e pênis no canal vaginal. Ao exame ultrassonográfico, constatou-se a presença de testículos em topografia subcutânea e intrabdominal, sem evidências de útero e ovários. Realizou-se laparotomia exploratória, orquiectomia e penectomia. Baseado nas características fenotípicas, ultrassonográficas e histológicas, conclui-se que o animal era pseudo-hermafrotida masculino.
Malaria is the world’s most widespread protozoan infection, being responsible for more than 445,000 annual deaths. Among the malaria parasites,
Plasmodium falciparum
is the most prevalent and lethal. ...In this context, the search for new antimalarial drugs is urgently needed.
P. falciparum
superoxide dismutase (PfSOD) is an important enzyme involved in the defense mechanism against oxidative stress. The goal of this study was to identify through hierarchical screening on pharmacophore models and molecular dynamics (MD), promising allosteric PfSOD inhibitors that do not show structural requirements for human inhibition. MD simulations of 1000 ps were performed on PfSOD using GROMACS 5.1.2. For this, the AMBER99SB-ILDN force field was adapted to describe the metal-containing system. The simulations indicated stability in the developed system. Therefore, a covariance matrix was generated, in which it was possible to identify residues with correlated and anticorrelated movements with the active site. These results were associated with the results found in the predictor of allosteric sites, AlloSitePro, which affirmed the ability of these residues to delimit an allosteric site. Then, after successive filtering of the Sigma-Aldrich® compounds database for HsSOD1 and PfSOD pharmacophores, 152 compounds were selected, also obeying Lipinski’s rule of 5. Further filtering of those compounds based on molecular docking results, toxicity essays, availability, and price filtering led to the selection of a best compound, which was then submitted to MD simulations of 20,000 ps on the allosteric site. The study concludes that the ZINC00626080 compound could be assayed against SODs.
Graphical Abstract
Plasmodium falciparum
superoxide dismutase
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