Evidence for a 304-day Orbital Period for GX 1+4

In this paper we report strong evidence for a ~304-day periodicity in the spin history of the accretion-powered pulsar GX 1+4 that is very likely to be a signature of the orbital period of the system. Using BATSE public-domain data, we show a highly-significant periodic modulation of the pulsar frequency from 1991 to date which is in excellent agreement with the ephemeris proposed by Cutler, Dennis & Dolan in 1986, which were based on a few events of enhanced spin-up that occurred during the pulsar's spin-up era in the 1970s. Our results indicate that the orbital period of GX 1+4 is 303.8+-1.1 days, making it by far the widest low-mass X-ray binary system known. A likely scenario for this system is an elliptical orbit in which the neutron star decreases its spin-down rate (or even exhibits a momentary spin-up behavior) at periastron passages due to the higher torque exerted by the accretion disk onto the magnetosphere of the neutron star.Comment: 5 pages, 2 figures, 1 single PS file, to appear in "Proceedings of the 5th Compton Symposium on Gamma-Ray Astrophysics", AI

Discovery of optical pulsations in V2116 Ophiuchi/GX 1+4

We report the detection of pulsations with $\sim 124$ s period in V2116 Oph, the optical counterpart of the low-mass X-ray binary GX 1+4. The pulsations are sinusoidal with modulation amplitude of up to 4% in blue light and were observed in ten different observing sessions during 1996 April-August using a CCD photometer at the 1.6-m and 0.6-m telescopes of Laborat\'orio Nacional de Astrof\'{\i}sica, in Brazil. The pulsations were also observed with the $UBVRI$ fast photometer. With only one exception the observed optical periods are consistent with those observed by the BATSE instrument on board the Compton Gamma Ray Observatory at the same epoch. There is a definite correlation between the observability of pulsations and the optical brightness of the system: V2116~Oph had $R$ magnitude in the range $15.3-15.5$ when the pulsed signal was detected, and $R = 16.0-17.7$ when no pulsations were present. The discovery makes GX 1+4 only the third of $\sim 35$ accretion-powered X-ray pulsars to be firmly detected as a pulsating source in the optical. The presence of flickering and pulsations in V2116 Oph adds strong evidence for an accretion disk scenario in this system. The absolute magnitude of the pulsed component on 1996 May 27 is estimated to be $M_V \sim -1.5$. The implied dimensions for the emitting region are 1.1 R_{\sun}, 3.2 R_{\sun}, and 7.0 R_{\sun}, for black-body spectral distributions with $T = 10^5$ K, $2 \times 10^4$ K, and $1 \times 10^4$ K, respectively.Comment: 9 pages, 3 figures in PostScript, latex, accepted for publication on the Astrophysical Journal Letter

The protoMIRAX Hard X-ray Imaging Balloon Experiment

The protoMIRAX hard X-ray imaging telescope is a balloon-borne experiment developed as a pathfinder for the MIRAX satellite mission. The experiment consists essentially in a coded-aperture hard X-ray (30-200 keV) imager with a square array (13$\times$13) of 2mm-thick planar CZT detectors with a total area of 169 cm$^2$. The total, fully-coded field-of-view is $21^{\circ}\times 21^{\circ}$ and the angular resolution is 1$^{\circ}$43'. In this paper we describe the protoMIRAX instrument and all the subsystems of its balloon gondola, and we show simulated results of the instrument performance. The main objective of protoMIRAX is to carry out imaging spectroscopy of selected bright sources to demonstrate the performance of a prototype of the MIRAX hard X-ray imager. Detailed background and imaging simulations have been performed for protoMIRAX balloon flights. The 3$\sigma$ sensitivity for the 30-200 keV range is ~1.9 $\times$ 10$^{-5}$ photons cm$^{-2}$ s$^{-1}$ for an integration time of 8 hs at an atmospheric depth of 2.7 g cm$^{-2}$ and an average zenith angle of 30$^{\circ}$. We have developed an attitude control system for the balloon gondola and new data handling and ground systems that also include prototypes for the MIRAX satellite. We present the results of Monte Carlo simulations of the camera response at balloon altitudes, showing the expected background level and the detailed sensitivity of protoMIRAX. We also present the results of imaging simulations of the Crab region. The results show that protoMIRAX is capable of making spectral and imaging observations of bright hard X-ray source fields. Furthermore, the balloon observations will carry out very important tests and demonstrations of MIRAX hardware and software in a near space environment.Comment: 9 pages, 13 figures, accepted for publication in Astronomy & Astrophysic

Improving the design of nozzles used in zamak high-pressure die-casting process

The injection of light alloys is an activity that requires a high effort on the part of Engineering to maintain its competitiveness. Due to the temperatures used, the wear of the components connected to this manufacturing process is quite intense, requiring a constant updating effort. This work was developed with a view to solving problems related to the excessive wear of injection nozzles used in the die casting process, and corresponding electrical resistances, with a view to increase its lifetime and improve the competitiveness of the process in the injection of low-cost parts in zamak for the automotive industry. To study and solve the problems of premature wear of the injection nozzles, the action-research method was used, which, through several iterations, allowed to arrive at an improved design of the nozzle, as well as the corresponding electrical resistance, thus increasing the life span of these components, also improving safety around the process and generating knowledge that can be transferable to other similar situations.The authors would like to thank Mr. Mário Cardoso from FicoCables, Lda. for his continuous support, proving interesting challenges for applied research. Authors would like to thank Ing. Fátima Andrade due to her help in preparing the samples and collecting images in the optical microscope. Authors would also thank INEGI - Instituto de Ciência e Inovação em Engenharia Mecânica e Engenharia Industrial, Porto, Portugal, due to its continuous support.info:eu-repo/semantics/publishedVersio

Dry Matter Yield of Promising \u3cem\u3ePanicum maximum\u3c/em\u3e Genotypes in Response to Phosphorus and Liming on Brazilian Savannah

Soil fertility of the Brazilian savannah Cerrado is naturally poor. Extensive areas of pastures located in the central part of territory are cultivated with Brachiaria grasses which are less demanding for soil nutrients and lime (Rao et al. 1998). On the other hand, Panicum maximum cultivars such as the high yielding Mombaça grass recommended to intensive beef and dairy cattle systems (Euclides et al. 2008), must be seeded with a higher amount of fertilizer, especially phosphorus (P). Consequently there is an effort for selection of P. maximum genotypes with low P demand and high responsiveness. The objective of this study was to evaluate dry matter yield of genotypes of P. maximum in response to doses of P and lime in the Brazilian Cerrado

Influence of copper on nickel-based catalysts in the conversion of glycerol

The catalytic transformation of glycerol to value-added compounds was investigated over bimetallic Ni-Cu/gamma-Al2O3 catalysts with Ni/Cu atomic ratios of 8/1, 4/1, 2/1, 1/1, 1/2, 1/4, and 1/8. XPS analysis revealed that the surface composition of the catalyst exhibited progressive enrichment of Cu as its content in the catalyst increased. H-2-chemisorption indicated that the total number of exposed Ni atoms decreased as the Cu content increased. As a result, deep hydrogenolysis to produce CH4 was inhibited by the addition of Cu to the Ni catalyst, yielding higher selectivity toward the dehydration products of glycerol such as hydroxyacetone.; FTIR spectra of adsorbed CO reveal that Cu asserts both geometric and electronic effects on the adsorption properties of Ni. The geometrical effect is visualized by the progressive disappearance of the bridge bound adsorbed CO on metallic Ni by the incorporation of Cu. This suggests that the deep hydrogenolysis of glycerol to CH4 formation requires an ensemble of adjacent active Ni atoms. The electronic effect of Cu on Ni is indicated by the red shift of the IR peak of adsorbed CO as the Cu content increases. The electronic interaction between Cu and Ni species was also substantiated by XANES results. HTREM revealed metal particles very well distributed on the support with particle size of 1.5 to 5 nm. The Ni Cu samples were not a total intermetallic alloys. (C) 2014 Elsevier B.V. All rights reserved.Postprint (published version

Mantle-to-crust metal transfer by nanomelts

The transfer of chalcophile metals across the continental lithosphere has been traditionally modeled based on their chemical equilibrium partitioning in sulfide liquids and silicate magmas. Here, we report a suite of Ni-Fe-Cu sulfide droplets across a trans-lithospheric magmatic network linking the subcontinental lithospheric mantle to the overlying continental crust. Petrographic characteristics and numerical calculations both support that the sulfide droplets were mechanically scavenged from the mantle source during partial melting and transported upwards by alkaline magmas rising through the continental lithosphere. Nanoscale investigation by high-resolution transmission electron microscopy (HR-TEM) documents the presence of galena (PbS) nanoinclusions within the sulfide droplets that are involved in the mantle-to-crust magma route. The galena nanoinclusions show a range of microstructural features that are inconsistent with a derivation of PbS by exsolution from the solid products of the Ni-Fe-Cu sulfide liquid. It is argued that galena nanoinclusions crystallized from a precursor Pb(-Cu)-rich nanomelt, which was originally immiscible within the sulfide liquid even at Pb concentrations largely below those required for attaining galena saturation. We suggest that evidence of immiscibility between metal-rich nanomelts and sulfide liquids during magma transport would disrupt the classical way by which metal flux and ore genesis are interpreted, hinting for mechanical transfer of nanophases as a key mechanism for sourcing the amounts of mantle-derived metals that can be concentrated in the crust.This research was supported by the BES-2017-079949 Ph.D. fellowship to E.S. The Spanish projects PID2019-111715GB-I00/AEI/10.13039/501100011033, NANOMET PID2022-138768OB-I00, and MECOBE ProyExcel_00705 provided funding for field emission gun–environmental scanning electron microscopy (FEG-ESEM), focused-ion beam (FIB) and high-resolution transmission electron microscopy (HR-TEM). M.F. and F.P. acknowledge financial support from the Australian Research Council through ARC Linkage Project LP190100785

Cardiotoxicity in haematological diseases : are the tyrosine kinase inhibitors imatinib and nilotinib safe?

Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017.Introduction: Chemotherapy-induced cardiotoxicity is a growing concern. The true cardiotoxic impact of new drugs such as tyrosine kinase inhibitors is unknown, especially the ones used for chronic myeloid leukaemia. We aim to evaluate nilotinib and imatinib induced cardiotoxicity. Methods: Single-center prospective study of consecutive patients with chronic myeloid leukaemia treated with tyrosine kinase inhibitors during 2015. Patients underwent an initial clinical, laboratorial and echocardiographic evaluation, repeated one year after therapy initiation. Results: Eleven patients were included [60.0 (11) years, 63.6% of males; 7 patients treated with imatinib and 4 with nilotinib]. After one year of follow-up, all patients remained in functional NYHA class I, with a similar Minnesota quality of life score [21 (20) vs. 21 (19), p = NS]. Also there was no difference in the biomarkers evaluated: cystatin-C [0.9 (0.2) vs. 0.8 (0.2) mg/L, p = NS; NT-proBNP 46.0 (45.0) vs. 42.0 (34.0) pg/mL, p = NS]. Previous to the TKI treatment, all patients had normal left ventricular ejection fraction (LVEF) [(median 67% (63–69)], without structural abnormalities. During the follow-up, there weren't differences regarding the LVEF, left atrium volume, E/A ratio, deceleration time, septal e', lateral e', E/e' ratio and tricuspid annular plane systolic excursion. With regard to myocardial deformation, all patients presented normal values of longitudinal, circumferential and radial strain in the baseline study, without changes during follow-up [DML -21.3 (6, 1) vs. -21.7 (6.0)%, p = NS; DMC -20.0 (9.3) vs. -22.3 (5.3)%, p = NS; DMR 36.9 (21.3) vs. 39.2 (19.2)%, p = NS]. In addition, there were no differences between the two tyrosine kinase inhibitors used, considering all the aforementioned variables. Conclusion: No clinical, laboratory or echocardiographic evidence of nilotinib and imatinib induced cardiotoxicity was observed, even when myocardial deformation analysis was performed. However, these results should be confirmed in larger studies, ideally multicentre, given the low incidence of chronic myeloid leukaemia.info:eu-repo/semantics/publishedVersio

Epidemiology and molecular phylogeny of Babesia sp. in Little Penguins Eudyptula minor in Australia

Blood parasites are potential threats to the health of penguins and to their conservation and management. Little penguins Eudyptula minor are native to Australia and New Zealand, and are susceptible to piroplasmids (Babesia), hemosporidians (Haemoproteus, Leucocytozoon, Plasmodium) and kinetoplastids (Trypanosoma). We studied a total of 263 wild little penguins at 20 sites along the Australian southeastern coast, in addition to 16 captive-bred little penguins. Babesia sp. was identified in seven wild little penguins, with positive individuals recorded in New South Wales, Victoria and Tasmania. True prevalence was estimated between 3.4% and 4.5%. Only round forms of the parasite were observed, and gene sequencing confirmed the identity of the parasite and demonstrated it is closely related to Babesia poelea from boobies (Sula spp.) and B. uriae from murres (Uria aalge). None of the Babesia-positive penguins presented signs of disease, confirming earlier suggestions that chronic infections by these parasites are not substantially problematic to otherwise healthy little penguins. We searched also for kinetoplastids, and despite targeted sampling of little penguins near the location where Trypanosoma eudyptulae was originally reported, this parasite was not detected