Detecting hot stars in the Galactic centre with combined near- and mid-infrared photometry

{The Galactic centre (GC) is a unique astrophysical laboratory to study the stellar population of galactic nuclei because it is the only galactic nucleus whose stars can be resolved down to milliparsec scales. However, the extreme and spatially highly variable interstellar extinction towards the GC poses a serious obstacle to photometric stellar classification.} {Our goal is to identify hot, massive stars in the nuclear stellar disc (NSD) region through combining near-infrared (NIR) and mid-infrared (MIR) photometry, and thus to demonstrate the feasibility of this technique, which may gain great importance with the arrival of the James Webb Space Telescope (JWST).} {We combined the GALACTICNUCLEUS NIR survey with the IRAC/Spitzer MIR survey of the GC. We applied the so-called Rayleigh-Jeans colour excess (RJCE) de-reddening method to our combined NIR-MIR data to identify potential hot stars in colour-magnitude diagrams (CMDs).} {Despite the very low angular resolution of IRAC we find 12 clear candidates for young massive stars among the $1\,065$ sources that meet our selection criteria. Seven out of these 12 stars are previously known hot, massive stars belonging to the Arches and Quintuplet clusters, as well as sources detected by the Hubble Space Telescope/NICMOS Paschen-$\alpha$ survey. Five of our massive star candidates have not been previously reported in the literature.} {We show that the RJCE method is a valuable tool to identify hot stars in the GC using photometry alone. Upcoming instruments with high angular resolution MIR imaging capabilities such as the JWST could surely make more substantial use of this de-reddening method and help establish a far more complete census of hot, young stars in the GC area than what is possible at the moment.}Comment: 6 pages, 6 figures, accepted for publication in A&

Compact Radio Sources within 30" of Sgr A*: Proper Motions, Stellar Winds and the Accretion Rate onto Sgr A*

Recent broad-band 34 and 44 GHz radio continuum observations of the Galactic center have revealed 41 massive stars identified with near-IR counterparts, as well as 44 proplyd candidates within 30" of Sgr A*. Radio observations obtained in 2011 and 2014 have been used to derive proper motions of eight young stars near Sgr A*. The accuracy of proper motion estimates based on near-IR observations by Lu et al. and Paumard et al. have been investigated by using their proper motions to predict the 2014 epoch positions of near-IR stars and comparing the predicted positions with those of radio counterparts in the 2014 radio observations. Predicted positions from Lu et al. show an rms scatter of 6 mas relative to the radio positions, while those from Paumard et al. show rms residuals of 20 mas, which is mainly due to uncertainties in the IR-based proper motions. Under the assumption of homogeneous ionized winds, we also determine the mass-loss rates of 11 radio stars, finding rates that are on average $\sim$2 times smaller than those determined from model atmosphere calculations and near-IR data. Clumpiness of ionized winds would reduce the mass loss rate of WR and O stars by additional factors of 3 and 10, respectively. One important implication of this is a reduction in the expected mass accretion rate onto Sgr A* from stellar winds by nearly an order of magnitude to a value of few$\times10^{-7}$ \msol\ yr$^{-1}$. Finally, we present the positions of 318 compact 34.5 GHz radio sources within 30\arcs\ of Sgr A*. At least 45 of these have stellar counterparts in the near-IR $K_s$ (2.18 $\mu$m) and $L'$ (3.8$\mu$m) bands.Comment: 30 pages, 4 figures, ApJ (in press

Interaction of diesel engine soot with NO2 and O2 at diesel exhaust conditions. Effect of fuel and engine operation mode

This work shows a study of the reactivity of twelve different types of soot with either NO2 or O2 under reacting conditions typically present in diesel particulate filters (DPFs). The soot samples were obtained from the combustion of four conventional and alternative fuels (diesel, biodiesel and two paraffinic fuels) in a diesel engine bench operated under three different engine operation modes: a typical urban-driving mode and two variations to this mode to assess the effect of the injection settings. The main objective of the work is to relate the oxidative reactivity of the soot to the nature and the origin of each sample. The possible simultaneous elimination of soot and NOx at typical diesel exhaust conditions is examined, as well. The reactivity tests were performed in a laboratory quartz gas flow reactor, discontinuous for the solid. The soot-NO2 interaction was studied with 200 ppm of NO2 at 500 °C and the soot-O2 interaction was studied with 5% O2 at 500 °C and 600 °C. The experimental results were used to determine the time needed for the complete conversion of carbon (t) through the use of the equations of the Shrinking Core Model for solid-gas reactions with decreasing size particle and chemical reaction control. In general, the t values show that the diesel fuel generates a less reactive soot than biodiesel or the alternative paraffinic fuels. In addition, increasing the injection pressure or adding a post-injection to the original injection strategy generates a more reactive soot. These findings point out that there is potential to achieve efficient regeneration processes in DPFs through other fuels than conventional ones and via engine calibration

Video monitoring of Sparidae temporal rhythms: three-year study by OBSEA cabled observatory

The abundance and composition of fish assemblages varies at different temporal scales as a product of diel and annual rhythms. In this study, we used a video-wired observatory (OBSEA, www.obsea.es) to monitor annual rhythms in a coastal fish assemblage with a 3-year data set (2012-2014). The photographs were acquired at 30 min frequency. Five species of the family Sparidae were studied (i.e. Dentex dentex, Diplodus sargus, Diplodus vulgaris, Diplodus annularis and Diplodus puntazzo) together with water temperature and daylength. The results of the annual rhythmicity analysis indicated that most of the peaks of abundance occured in the autumn months. Results suggest differentially temporal use of the reproductive or trophic niche.Peer ReviewedPostprint (published version

The Efficacy and Effectiveness of Education for Preventing and Treating Non-Specific Low Back Pain in the Hispanic Cultural Setting: A Systematic Review

A systematic review was conducted to assess the efficacy and effectiveness of education programs to prevent and treat low back pain (LBP) in the Hispanic cultural setting. Electronic and manual searches identified 1148 unique references. Nine randomized clinical trials (RCTs) were included in this review. Methodological quality assessment and data extraction followed the recommendations from the Cochrane Back Pain Review Group. Education programs which were assessed focused on active management (3 studies), postural hygiene (7), exercise (4) and pain neurophysiology (1). Comparators were no intervention, usual care, exercise, other types of education, and different combinations of these procedures. Five RCTs had a low risk of bias. Results show that: (a) education programs in the school setting can transmit potentially useful knowledge for LBP prevention and (b) education programs for patients with LBP improve the outcomes of usual care, especially in terms of disability. Education on pain neurophysiology improves the results of education on exercise, and education on active management is more effective than “sham” education and education on postural hygiene. Future studies should assess the comparative or summatory effects of education on exercise, education on pain neurophysiology and education on active management, as well as explore their efficiency

A novel dense granule protein, GRA41, regulates timing of egress and calcium sensitivity in Toxoplasma gondii

Toxoplasma gondii is an obligate intracellular apicomplexan parasite with high seroprevalence in humans. Repeated lytic cycles of invasion, replication, and egress drive both the propagation and the virulence of this parasite. Key steps in this cycle, including invasion and egress, depend on tightly regulated calcium fluxes and, although many of the calcium-dependent effectors have been identified, the factors that detect and regulate the calcium fluxes are mostly unknown. To address this knowledge gap, we used a forward genetic approach to isolate mutants resistant to extracellular exposure to the calcium ionophore A23187. Through whole genome sequencing and complementation, we have determined that a nonsense mutation in a previously uncharacterised protein is responsible for the ionophore resistance of one of the mutants. The complete loss of this protein recapitulates the resistance phenotype and importantly shows defects in calcium regulation and in the timing of egress. The affected protein, GRA41, localises to the dense granules and is secreted into the parasitophorous vacuole where it associates with the tubulovesicular network. Our findings support a connection between the tubulovesicular network and ion homeostasis within the parasite, and thus a novel role for the vacuole of this important pathogen

The Efficacy and Effectiveness of Education for Preventing and Treating Non-Specific Low Back Pain in the Hispanic Cultural Setting: A Systematic Review

[EN] A systematic review was conducted to assess the efficacy and effectiveness of education programs to prevent and treat low back pain (LBP) in the Hispanic cultural setting. Electronic and manual searches identified 1148 unique references. Nine randomized clinical trials (RCTs) were included in this review. Methodological quality assessment and data extraction followed the recommendations from the Cochrane Back Pain Review Group. Education programs which were assessed focused on active management (3 studies), postural hygiene (7), exercise (4) and pain neurophysiology (1). Comparators were no intervention, usual care, exercise, other types of education, and different combinations of these procedures. Five RCTs had a low risk of bias. Results show that: (a) education programs in the school setting can transmit potentially useful knowledge for LBP prevention and (b) education programs for patients with LBP improve the outcomes of usual care, especially in terms of disability. Education on pain neurophysiology improves the results of education on exercise, and education on active management is more effective than “sham” education and education on postural hygiene. Future studies should assess the comparative or summatory effects of education on exercise, education on pain neurophysiology and education on active management, as well as explore their efficiency.S