Constraining DM through 21 cm observations

Beyond reionization epoch cosmic hydrogen is neutral and can be directly observed through its 21 cm line signal. If dark matter (DM) decays or annihilates the corresponding energy input affects the hydrogen kinetic temperature and ionized fraction, and contributes to the Ly_alpha background. The changes induced by these processes on the 21 cm signal can then be used to constrain the proposed DM candidates, among which we select the three most popular ones: (i) 25-keV decaying sterile neutrinos, (ii) 10-MeV decaying light dark matter (LDM) and (iii) 10-MeV annihilating LDM. Although we find that the DM effects are considerably smaller than found by previous studies (due to a more physical description of the energy transfer from DM to the gas), we conclude that combined observations of the 21 cm background and of its gradient should be able to put constrains at least on LDM candidates. In fact, LDM decays (annihilations) induce differential brightness temperature variations with respect to the non decaying/annihilating DM case up to Delta_delta T_b=8 (22) mK at about 50 (15) MHz. In principle this signal could be detected both by current single dish radio telescopes and future facilities as LOFAR; however, this assumes that ionospheric, interference and foreground issues can be properly taken care of.Comment: 9 pages, submitted to MNRA

Particle energy cascade in the intergalactic medium

We study the development of high-energy (Ein <= 1 TeV) cascades produced by a primary electron of energy Ein injected into the intergalactic medium (IGM). To this aim we have developed the new code MEDEA (Monte Carlo Energy Deposition Analysis) which includes Bremsstrahlung and inverse Compton (IC) processes, along with H/He collisional ionizations and excitations, and electron-electron collisions. The cascade energy partition into heating, excitations and ionizations depends primarily not only on the IGM ionized fraction, xe, but also on redshift, z, due to IC on cosmic microwave background (CMB) photons. While Bremsstrahlung is unimportant under most conditions, IC becomes largely dominant at energies Ein >= 1 MeV. The main effect of IC at injection energies Ein <= 100 MeV is a significant boost of the fraction of energy converted into low-energy photons (h\u3bd < 10.2 eV) which do not further interact with the IGM. For energies Ein >= 1 GeV CMB photons are preferentially upscattered within the X-ray spectrum (h\u3bd > 104 eV) and can free stream to the observer. Complete tables of the fractional energy depositions as a function of redshift, Ein and ionized fraction are given. Our results can be used in many astrophysical contexts, with an obvious application related to the study of decaying/annihilating dark matter (DM) candidates in the high-z Universe

II CONGRESO INTERNACIONAL DE EVALUACI 3N DEL DESEMPE 1O, VALORA 2017

Los conocimientos surgen de procesos que relaciona vivencias e informaci\uf3n que se adquiere a trav\ue9s de sistemas de informaci\uf3n metodol\uf3gicos y cotidianos, lo que impacta en formas creativas de interpretar realidades mediante procesos cognitivos, que involucren un cambio en la forma de ser de las personas para estar en sociedad, la socioformaci\uf3n aporta m\ue9todos acciones que implica utilizar vivencias de los alumnos, modificar la din\ue1mica del aprendizaje, lograr la comprensi\uf3n de una realidad cada m\ue1s difusa, la cual la globalizaci\uf3n es protagonista principal; el evento del II Congreso Internacional de Evaluaci\uf3n del Desempe\uf1o Valora 2017, llevado a cabo el d\ueda 6 y 7 de octubre, de manera virtual, como objetivo se promovieron propuestas de investigaci\uf3n y divulgaci\uf3n en el \ue1mbito educativo, los expertos proponen desarrollar una evaluaci\uf3n desde un concepto socioformativo, que impacte en el dise\uf1o de instrumentos, validaci\uf3n, evaluaci\uf3n, aplicaci\uf3n de pruebas, generar procesos sist\ue9micos sobre la evaluaci\uf3n del aprendizaje; los investigadores de instituciones educativas y de prestadoras de servicio, promueven metodolog\uedas que respondan a estos cambios e impacte en el docente y alumno para una eficiencia educativa real; los planes, programas, sistemas, teor\ueda, praxis, el ser, saber convivir son elementos generales que deben de integrarse a todo proceso educativo, presentados en planes de clase que sean promotores de una formaci\uf3n sostenible sobre todo que responda a las exigencias del entorno personal, en el \ue1mbito de poblaci\uf3n local, as\ued como con una asimilaci\uf3n de respuesta al proceso global. Palabras clave: desempe\uf1o, educaci\uf3n, evaluaci\uf3n, planeaci\uf3n, socioformaci\uf3n. ABSTRACT The knowledge arises from processes that relate experiences and information that is acquired through methodological and daily information systems, which impacts on creative ways of interpreting realities through cognitive processes, which involve a change in the way of being of people to be in society, socioformation provides methods that involve using students' experiences, modifying the dynamics of learning, achieving an understanding of a more diffuse reality, which globalization is the main protagonist; the event of the II International Congress of Evaluation of Performance Values 2017, held on October 6 and 7, in a virtual way, as an objective, research and dissemination proposals were promoted in the educational field, the experts propose to develop an evaluation from a socioformative concept, which impacts on the design of instruments, validation, evaluation, application of tests, generate systemic processes on the evaluation of learning; researchers from educational institutions and service providers promote methodologies that respond to these changes and impact the teacher and student for real educational efficiency; plans, programs, systems, theory, praxis, being, knowing how to live together are general elements that should be integrated into any educational process, presented in class plans that are promoters of sustainable training, especially that responds to the demands of the environment personnel, in the area of local population, as well as with an assimilation of response to the global process. Keywords: performance, education, evaluation, planning, socioformation. <br

Radio views of cosmic reionization

We use numerical simulations of cosmic reionization and radiative processes related to the HI 21 cm emission line to produce synthetic radio maps as seen by next generation radio telescopes that will operate at low radio frequencies (e.g. LOFAR). Two different scenarios, in which the end of reionization occurs early (z approx 13) or late (z approx 8) depending on the Initial Mass Function (IMF) of the first stars and ionizing photon escape fraction, have been explored. For each of these models we produce synthetic HI 21 cm emission maps by convolving the simulation outputs with the provisional LOFAR sampling function in the frequency range 76-140 MHz. If reionization occurs late, LOFAR will be able to detect individual HI structures on arcmin scales, emitting at a brightness temperature of approx 35 mK as a 3-sigma signal in about 1000 hours of observing time. In the case of early reionization, the detection would be unlikely, due to decreased sensitivity and increased sky temperatures. These results assume that ionospheric, interference and foreground issues are fully under control.Comment: 6 pages, 3 figures, Minor changes following referee repor

Generation and analysis of an Eucalyptus globulus cDNA library constructed from seedlings subjected to low temperature conditions

Eucalyptus globulus is the most important commercial temperate hardwood in the world because of its wood properties and due to its characteristics for biofuel production. However, only a very low number of expressed sequence tags (ESTs) are publicly available for this tree species. We constructed a cDNA from E. globulus seedlings subjected to low temperature and sequenced 9,913 randomly selected clones, generating 8,737 curated ESTs. The assembly produced 1,062 contigs and 3,879 singletons forming a Eucalyptus unigene set. Based on BLASTX analysis, 89.3% of the contigs and 88.5% of the singletons had significant similarity to known genes in the non-redundant database of GenBank. The Eucalyptus unigene set generated is a valuable public resource that provides an initial model for genes and regulatory pathways involved in cell wall biosynthesis at low temperature

Effect of sulphate concentration and sulphide desorption on the combined removal of organic matter and sulphate from wastewaters using expanded granular sludge bed (EGSB) reactors

During the application of anaerobic processes to high sulphate concentration wastewaters, operational problems are expected due to the occurrence of sulphate reduction. Sulphide production reduces effluent quality and may produce inhibition. The application of Expanded Granular Sludge Bed (EGSB) reactors for the combined removal of organic matter and sulphate was studied at different COD/sulphate and 3 values of pH. During the EGSB reactor operation, most of the sulphide remains in the liquid phase reducing effluent quality. The inclusion of a desorption column in the recirculation of the EGSB reactor promotes mass transfer to the gas phase, reducing the sulphide concentration in the liquid phase, significantly decreasing the chemical oxygen demand of the effluent

Effect of a commercial pectinmethylesterase on tomato paste consistency

Background: Consistency is one of the main traits that define commercial quality and price of tomato paste. Pectins are partially responsible for consistency in tomato paste, therefore enzymatic pectin modification could be used to increase paste consistency. Results: This work reports the effects of a commercial enzymatic preparation of pectin-methyl-esterase (PME) (NovoShape\u2122) on tomato paste consistency taking into account variables as enzyme/substrate ratio (0,1% w/w - 1% w/w), reaction time (0 hr - 3 hrs) and reaction temperature (40\ubaC-60\ubaC). The results indicate that NovoShape\u2122 increased consistency when reaction temperature ranged from 40 to 50\ubaC with an enzyme/substrate ratio of 0.5 to 1 (l PME solution/g tomato paste on dry base). On the other hand, enzymatic treatment was not effective at 60\ubaC with an enzyme/substrate ratio of 0.1%. Conclusions: Based on these results, addition of NovoShape\u2122 is a good technological approach to increase tomato paste consistency

The application of polymerized lipid vesicles as colorimetric biosensors for real-time detection of pathogens in drinking water

The inadequate treatments given to the served waste water which are disposal to the rivers and sea coast are the major sources of faecal Microorganisms and enteric bacterial pathogens. They are among the most serious effects of water pollution bringing risks on public health. None of the current methods for detection of pathogens offer real-time on site solutions, are capable of delivering a simple visual detection signal, or can be easily instrumented as an indicator of the presence of a pathogen in water. The use of lipid vesicles incorporating Polydiacetylenes (PDAs) for the development of biosensors for \u201creal-time\u201d detection of pathogens has become an alternative, due to its potential for simple colorimetric response against harmful environmental effectors. However, its actual application in the field has been complicated because lipid vesicles are unable to respond specifically to environmental changes. In this paper, we report several experimental trials leading to improved response in the detection of flagellated pathogens in drinking water. Chromatic biomimetic membranes of TRCDA/DMPC and TRCDA/DMPC/Tryptophan were used in agar and liquid media, which were challenged with different amounts of Escherichia coli and Salmonella typhimurium . In addition, the effect of some divalent cations on the interaction with vesicles TRCDA/DMPC was investigated. The results indicated an improvement in the response times, both visually and quantitatively, through the use of TRIS-EDTA and proper growing conditions for E. coli and Salmonella. With the application of both conditions, it was possible by incubation at 35\ubaC to promote bacterial growth, therefore avoiding a dramatic effect on the colour change over control samples which may invalidate the test. Our experiments indicated that the minimum bacterial concentration necessary to produce the transition from blue to red on the vesicles as biosensor approaches 108 CFU/ml within 4 hrs, faster than traditional methods such as MPN or plate count agar. We present here incubations of samples of contaminated water at 35\ubaC, in agar plates containing chromatic biomimetic membranes of TRCDA/DMPC. A measurable colour transition is obtained within a reaction time of four hrs, which compares favourably with detection times between seven to 24 hrs corresponding to available tests