Behavioural and electrophysiological responses of female Anopheles gambiae mosquitoes to volatiles from a mango bait

Attractive Toxic Sugar Baits (ATSB) are used in a “lure-and-kill” approach for management of the malaria vector Anopheles gambiae, but the active chemicals were previously unknown. Here we collected volatiles from a mango, Mangifera indica, juice bait which is used in ATSBs in Tanzania and tested mosquito responses. In a Y-tube olfactometer, female mosquitoes were attracted to the mango volatiles collected 24–48 h, 48–72 h and 72–96 h after preparing the bait but volatiles collected at 96–120 h were no longer attractive. Volatile analysis revealed emission of 23 compounds in different chemical classes including alcohols, aldehydes, alkanes, benzenoids, monoterpenes, sesquiterpenes and oxygenated terpenes. Coupled GC-electroantennogram (GCEAG) recordings from the antennae of An. gambiae showed robust responses to 4 compounds: humulene, (E)-caryophyllene, terpinolene and myrcene. In olfactometer bioassays, mosquitoes were attracted to humulene and terpinolene. (E)-caryophyllene was marginally attractive while myrcene elicited an avoidance response with female mosquitoes. A blend of humulene, (E)- caryophyllene and terpinolene was highly attractive to females (P < 0.001) when tested against a solvent blank. Furthermore, there was no preference when this synthetic blend was offered as a choice against the natural sample. Our study has identified the key compounds from mango juice baits that attract An. gambiae and this information may help to improve the ATSBs currently used against malaria vectors

A twin-disc study of the role of the surface quality achieved by grinding on the wear resistance and rolling contact fatigue behavior of wheel/rail pairs

The tribological behavior of wheel and rail material twin-disc samples prepared under laboratory-controlled grinding operations was studied. A laboratory grinding device was designed and validated to produce similar results to those found in the field in terms of surface quality and presence of white etching layer (WEL). The test samples were evaluated in a twin-disc machine under dry and lubricated conditions. The results showed that the surface finishing parameters and the microstructure change greatly depending on the surface preparation procedure, and that such changes affect the tribological response of the samples. The wear rates of the tribological tests for the different rail surface qualities showed a reduction of 47.4% for the lubricated tests and 7.3% for the dry tests when the surfaces of the rail specimens were finished by grinding. This is only applied when the WEL thickness was less than 4 μm

Numerical modelling of multi-directional thin-ply carbon/glass hybrid composites with open holes under tension

Many researchers have used continuum damage mechanics for modelling damage in standard composites. This approach is intrinsically suitable for modelling the progress of damage modes spread over the specimen, which has been widely reported in pseudo-ductile hybrid composites. To the authors' best knowledge, this paper is the first numerical model based on continuum damage mechanics proposed for pseudo-ductile hybrid composites. The proposed constitutive model uses a thermodynamically consistent approach to compute the damage progression in the material. Experimental stress-strain curves and the failure pattern of carbon/glass hybrid lay-ups with gradual failure taken from the literature are compared against the numerical results to validate the model. The model provides a mesh-independent solution with a good prediction of the damage sequence and the overall stress-strain curves of the notched samples. A good correlation in size, location and type of damage mechanism was found between numerical and experimental results. This study indicates that the proposed model can provide a good prediction of the onset and propagation of the damage in notched hybrid composite laminates

Comportamiento microestructural de una fundición de magnesio puro con control en la temperatura de solidificación

The study of the microstructural behavior of pure magnesium (Mg) after a casting process conducted in a furnace of own manufacture with controlled atmosphere and solidification temperature control is presented. This study aimed to determine the change in the composition of the Mg by SEM/EDS, owing to the protective atmosphere used. Besides, the change in the microstructure of Mg was studied by performing solidification in a mold at temperature of 200°C within the casting system, in which a poor oxygen atmosphere was used with a mixture of CO2 and SF6. Through the compositional evaluation was evident a change in the material owing to the gases used and the elements that interacted with the Mg. It was possible to see a change in the microstructure of the Mg by optical microscopy analysis and SEM, observing differences in the amount and distribution of particles and inclusions present in the Mg. After casting process, the generation of a dendritic structure was observed, but not in the base material. Finally, using the manufactured casting system was possible to obtain an ingot of Mg with similar conditions to the base material, in addition to obtain a microstructure with finer grain and better distribution of particles in the matrix.En este trabajo se estudió el comportamiento microestructural del magnesio (Mg) puro luego de ser sometido a un proceso de fundición realizado en un horno con control de atmósfera de fabricación propia y con control de la temperatura de solidificación. Con este trabajo se buscó determinar el cambio en la composición del Mg debido a la atmosfera protectora utilizada mediante SEM/EDS  y se estudió el cambio en la microestructura del Mg puro luego de realizar una solidificación en una lingotera a una temperatura de 200°C dentro del sistema de fundición, en el cuál se utilizó una atmósfera pobre en oxígeno con una mezcla de CO2 y SF6. De la evaluación composicional se evidenció un cambio en el material debido a los gases usados y los elementos con los que interactuó el Mg. Se pudo observar un cambio en la microestructura del Mg por medio de análisis de microscopía óptica y SEM, observando diferencias en la cantidad y distribución de inclusiones y partículas presentes en el Mg. Además, se observó la generación de una estructura dendrítica tras el proceso de fundición, lo cual no se evidenció en el material base. Finalmente, con el sistema de fundición fabricado se logró obtener un lingote de Mg con condiciones similares al material base, además obtener una microestructura con granos más finos y una mejor distribución de partículas en la matriz

Comportamiento microestructural de una fundición de magnesio puro con control en la temperatura de solidificación

The study of the microstructural behavior of pure magnesium (Mg) after a casting process conducted in a furnace of own manufacture with controlled atmosphere and solidification temperature control is presented. This study aimed to determine the change in the composition of the Mg by SEM/EDS, owing to the protective atmosphere used. Besides, the change in the microstructure of Mg was studied by performing solidification in a mold at temperature of 200°C within the casting system, in which a poor oxygen atmosphere was used with a mixture of CO2 and SF6. Through the compositional evaluation was evident a change in the material owing to the gases used and the elements that interacted with the Mg. It was possible to see a change in the microstructure of the Mg by optical microscopy analysis and SEM, observing differences in the amount and distribution of particles and inclusions present in the Mg. After casting process, the generation of a dendritic structure was observed, but not in the base material. Finally, using the manufactured casting system was possible to obtain an ingot of Mg with similar conditions to the base material, in addition to obtain a microstructure with finer grain and better distribution of particles in the matrix.En este trabajo se estudió el comportamiento microestructural del magnesio (Mg) puro luego de ser sometido a un proceso de fundición realizado en un horno con control de atmósfera de fabricación propia y con control de la temperatura de solidificación. Con este trabajo se buscó determinar el cambio en la composición del Mg debido a la atmosfera protectora utilizada mediante SEM/EDS  y se estudió el cambio en la microestructura del Mg puro luego de realizar una solidificación en una lingotera a una temperatura de 200°C dentro del sistema de fundición, en el cuál se utilizó una atmósfera pobre en oxígeno con una mezcla de CO2 y SF6. De la evaluación composicional se evidenció un cambio en el material debido a los gases usados y los elementos con los que interactuó el Mg. Se pudo observar un cambio en la microestructura del Mg por medio de análisis de microscopía óptica y SEM, observando diferencias en la cantidad y distribución de inclusiones y partículas presentes en el Mg. Además, se observó la generación de una estructura dendrítica tras el proceso de fundición, lo cual no se evidenció en el material base. Finalmente, con el sistema de fundición fabricado se logró obtener un lingote de Mg con condiciones similares al material base, además obtener una microestructura con granos más finos y una mejor distribución de partículas en la matriz

Comparing benefits from many possible computed tomography lung cancer screening programs: Extrapolating from the National Lung Screening Trial using comparative modeling

Background: The National Lung Screening Trial (NLST) demonstrated that in current and former smokers aged 55 to 74 years, with at least 30 pack-years of cigarette smoking history and who had quit smoking no more than 15 years ago, 3 annual computed tomography (CT) screens reduced lung cancer-specific mortality by 20% relative to 3 annual chest X-ray screens. We compared the benefits achievable with 576 lung cancer screening programs that varied CT screen number and frequency, ages of screening, and eligibility based on smoking. Methods and Findings: We used five independent microsimulation models with lung cancer natural history parameters previously calibrated to the NLST to simulate life histories of the US cohort born in 1950 under all 576 programs. 'Efficient' (within model) programs prevented the greatest number of lung cancer deaths, compared to no screening, for a given number of CT screens. Among 120 'consensus efficient' (identified as efficient across models) programs, the average starting age was 55 years, the stopping age was 80 or 85 years, the average minimum pack-years was 27, and the maximum years since quitting was 20. Among consensus efficient programs, 11% to 40% of the cohort was screened, and 153 to 846 lung cancer deaths were averted per 100,000 people. In all models, annual screening based on age and smoking eligibility in NLST was not efficient; continuing screening to age 80 or 85 years was more efficient. Conclusions: Consensus results from five models identified a set of efficient screening programs that include annual CT lung cancer screening using criteria like NLST eligibility but extended to older ages. Guidelines for screening should also consider harms of screening and individual patient characteristics

Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy

We review HB stars in a broad astrophysical context, including both variable and non-variable stars. A reassessment of the Oosterhoff dichotomy is presented, which provides unprecedented detail regarding its origin and systematics. We show that the Oosterhoff dichotomy and the distribution of globular clusters (GCs) in the HB morphology-metallicity plane both exclude, with high statistical significance, the possibility that the Galactic halo may have formed from the accretion of dwarf galaxies resembling present-day Milky Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the second-parameter problem is presented. A technique is proposed to estimate the HB types of extragalactic GCs on the basis of integrated far-UV photometry. The relationship between the absolute V magnitude of the HB at the RR Lyrae level and metallicity, as obtained on the basis of trigonometric parallax measurements for the star RR Lyrae, is also revisited, giving a distance modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are studied. Finally, the conductive opacities used in evolutionary calculations of low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and Space Scienc

Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum

We report a first measurement for ultra-high energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the `ankle' at $\lg(E/{\rm eV})=18.5-19.0$ differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass $A > 4$. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report Numbe

The large trans-Neptunian object 2002 TC302 from combined stellar occultation, photometry, and astrometry data

Context. Deriving physical properties of trans-Neptunian objects is important for the understanding of our Solar System. This requires observational efforts and the development of techniques suitable for these studies. Aims. Our aim is to characterize the large trans-Neptunian object (TNO) 2002 TC302. Methods. Stellar occultations offer unique opportunities to determine key physical properties of TNOs. On 28 January 2018, 2002 TC302 occulted a mv ~ 15.3 star with designation 593-005847 in the UCAC4 stellar catalog, corresponding to Gaia source 130957813463146112. Twelve positive occultation chords were obtained from Italy, France, Slovenia, and Switzerland. Also, four negative detections were obtained near the north and south limbs. This represents the best observed stellar occultation by a TNO other than Pluto in terms of the number of chords published thus far. From the 12 chords, an accurate elliptical fit to the instantaneous projection of the body can be obtained that is compatible with the near misses. Results. The resulting ellipse has major and minor axes of 543 ± 18 km and 460 ± 11 km, respectively, with a position angle of 3 ± 1 degrees for the minor axis. This information, combined with rotational light curves obtained with the 1.5 m telescope at Sierra Nevada Observatory and the 1.23 m telescope at Calar Alto observatory, allows us to derive possible three-dimensional shapes and density estimations for the body based on hydrostatic equilibrium assumptions. The effective diameter in equivalent area is around 84 km smaller than the radiometrically derived diameter using thermal data from Herschel and Spitzer Space Telescopes. This might indicate the existence of an unresolved satellite of up to ~300 km in diameter, which is required to account for all the thermal flux, although the occultation and thermal diameters are compatible within their error bars given the considerable uncertainty of the thermal results. The existence of a potential satellite also appears to be consistent with other ground-based data presented here. From the effective occultation diameter combined with absolute magnitude measurements we derive a geometric albedo of 0.147 ± 0.005, which would be somewhat smaller if 2002 TC302 has a satellite. The best occultation light curves do not show any signs of ring features or any signatures of a global atmosphere.Funding from Spanish projects AYA2014-56637-C2-1-P, AYA2017-89637-R, from FEDER, and Proyecto de Excelencia de la Junta de Andalucía 2012-FQM1776 is acknowledged. We would like to acknowledge financial support by the Spanish grant AYA-RTI2018-098657-JI00 “LEO-SBNAF” (MCIU/AEI/FEDER, UE) and the financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV- 2017-0709). Part of the research received funding from the European Union’s Horizon 2020 Research and Innovation Programme, under grant agreement no. 687378 and from the ERC programme under Grant Agreement no. 669416 Lucky Star. The following authors acknowledge the respective CNPq grants: FB-R 309578/2017-5; RV-M 304544/2017-5, 401903/2016-8; J.I.B.C. 308150/2016-3; MA 427700/2018-3, 310683/2017-3, 473002/2013-2. This study was financed in part by the Coordenação de Aperfeiaçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001 and the National Institute of Science and Technology of the e-Universe project (INCT do e-Universo, CNPq grant 465376/2014-2). GBR acknowledges CAPES-FAPERJ/PAPDRJ grant E26/203.173/2016, MA FAPERJ grant E-26/111.488/2013 and ARGJr FAPESP grant 2018/11239-8. E.F.-V. acknowledges support from the 2017 Preeminent Postdoctoral Program (P3) at UCF. C.K., R.S., A.F-T., and G.M. have been supported by the K-125015 and GINOP-2.3.2-15-2016-00003 grants of the Hungarian National Research, Development and Innovation Office (NKFIH), Hungary. G.M. was also supported by the Hungarian National Research, Development and Innovation Office (NKFIH) grant PD-128 360. R.K. and T.P. were supported by the VEGA 2/0031/18 grant