Constraining scalar fields with stellar kinematics and collisional dark matter

The existence and detection of scalar fields could provide solutions to long-standing puzzles about the nature of dark matter, the dark compact objects at the centre of most galaxies, and other phenomena. Yet, self-interacting scalar fields are very poorly constrained by astronomical observations, leading to great uncertainties in estimates of the mass $m_\phi$ and the self-interacting coupling constant $\lambda$ of these fields. To counter this, we have systematically employed available astronomical observations to develop new constraints, considerably restricting this parameter space. In particular, by exploiting precise observations of stellar dynamics at the centre of our Galaxy and assuming that these dynamics can be explained by a single boson star, we determine an upper limit for the boson star compactness and impose significant limits on the values of the properties of possible scalar fields. Requiring the scalar field particle to follow a collisional dark matter model further narrows these constraints. Most importantly, we find that if a scalar dark matter particle does exist, then it cannot account for both the dark-matter halos and the existence of dark compact objects in galactic nucleiComment: 23 pages, 8 figures; accepted for publication by JCAP after minor change

Knowledge and organizational performance in franchised restaurants in Colombia

Purpose: The aim of this study is to analyze the importance of knowledge in reaching organizational objectives (long-term organizational goals) and in constructing competitive advantage (value-added) and identifying the impact of this knowledge on organizational performance of franchised restaurants in an emerging market. Design/methodology/approach: Likert-scale surveys were applied to 50 managers representing 80% of the franchised restaurant business in Bogotá, Colombia. Data processing was performed through descriptive statistics, multiple correspondences analysis (MCA) and logit regression (LR). Findings: Results indicate that 1) of the set of factors that contribute to the achievement of franchise objectives, personnel motivation and continuous environmental scanning are the most important; 2) the primary sources of knowledge for construction of competitive advantage are clients and providers; and 3) the most significant impact of knowledge occurs in human resource and organizational development and in increased earnings. Practical implications: The study provides evidence of the role and the impact of knowledge in the performance of franchised restaurants and thereby contributes to academic analysis and managerial decision-making. Originality: This study provides aggregated and disaggregated analysis of empirical data on the role of knowledge in franchised restaurants, a sector with limited extant research in the context of emerging markets. © 2020, Emerald Publishing Limited

Caractérisation des systèmes de production ovine dans la zone de "Sierra del Segura y la Sagra", Espagne

[FR] Le présent article se propose d¿analyser les caractéristiques les plus saillantes du secteur ovin dans une partie de la zone géographique sous Indication Géographique Protégée (IGP) "Cordero de Segura y la Sagra". Une enquête a été menée sur 93 propriétaires d¿élevages, dans l'objectif de connaître la situation du secteur dans cette zone. Les questions concernaient les sujets suivants: caractéristiques du troupeau, âge, niveau d'études, ouvriers à la ferme, continuité des activités de la ferme. La taille moyenne du troupeau est de 378 animaux et la race "Segureña" est prédominante (99%). Dans 93,4% des cas l¿éleveur travaille à temps plein dans l¿exploitation et le revenu principal est la vente d¿agneaux pour la viande, mais seulement 9,7% des éleveurs font partie d¿une coopérative pour la commercialisation. L'âge moyen du fermier est de 50 ans et 87,1% des éleveurs n¿ont pas d¿études ou de faible niveau. La moyenne du travail employé est de 1,31 UTA, essentiellement de type familial. Seulement dans 12% des cas il existe une sécurité de la continuité de l'activité. Les résultats obtenus montrent qu'il est nécessaire de parvenir à de meilleures conditions socioéconomiques pour les exploitations dans la zone étudiée. L'IGP "Cordero de Segura y la Sagra" pourrait être utile pour améliorer ces aspects.[EN] The aim of this study is to present the basic characteristics which define the sheep systems in some zones of the PGI Cordero de Segura y la Sagra protected area, in order to bring about actions to improve the competitiveness of such systems. A survey has been conducted among 93 farm owners. The questionnaire included questions regarding herd characteristics, age, educational level, workers, and continuity of the farm activity. The average herd size is 378 animals and the Segureña breed sheep is predominant (99 percent). In 93.5 percent of cases the owner works full time on the farm and the main economic benefit is the sale of lambs for meat, but only 9.7 percent of farmers belong to some kind of marketing cooperative. The average farmer's age is 50 years old and a high percentage (87.1 percent) has no education or a very basic one. The year work unit (YWU) is 1.31 and the work is mainly of family type. In only 12 percent of the cases the continuity of the activity is assured. The above analysed aspects show that it is necessary to achieve better socioeconomic conditions of farms. The PGI Cordero de Segura y la Sagra could be useful to improve these aspects. Therefore we suggest that the PGI must be promoted among farmers, especially among young people.Navarro-Ríos, M.; Marín-Bernal, A.; Martí, A.; Fernández Martínez, CJ. (2011). Characterizacion of Segureña sheep production system in the area of Sierra del Segura y la Sagra, Spain. Options Mediterraneennes. Serie A: Seminaires Mediterraneens. (100):211-216. http://hdl.handle.net/10251/107315S21121610

Effects of Residue Background Events in Direct Dark Matter Detection Experiments on the Determination of the WIMP Mass

In the earlier work on the development of a model-independent data analysis method for determining the mass of Weakly Interacting Massive Particles (WIMPs) by using measured recoil energies from direct Dark Matter detection experiments directly, it was assumed that the analyzed data sets are background-free, i.e., all events are WIMP signals. In this article, as a more realistic study, we take into account a fraction of possible residue background events, which pass all discrimination criteria and then mix with other real WIMP-induced events in our data sets. Our simulations show that, for the determination of the WIMP mass, the maximal acceptable fraction of residue background events in the analyzed data sets of O(50) total events is ~20%, for background windows of the entire experimental possible energy ranges, or in low energy ranges; while, for background windows in relatively higher energy ranges, this maximal acceptable fraction of residue background events can not be larger than ~10%. For a WIMP mass of 100 GeV with 20% background events in the windows of the entire experimental possible energy ranges, the reconstructed WIMP mass and the 1-sigma statistical uncertainty are ~97 GeV^{+61%}_{-35%} (~94 GeV^{+55%}_{-33%} for background-free data sets).Comment: 27 pages, 22 eps figures; v2: revised version for publication, references added and update

Thermal Diffusivity Measurements In Vegetable Oils With Thermal Lens Technique

The thermal lens technique to measure the thermal diffusivity in vegetable oils was discussed. The Amazonian species and olive oils were used as samples. The time resolved spectra were measured using an automatic system and the obtained data were used to solve the thermal property of each oil.741 II697699Gordon, J.P., Leite, R.C.C., Moore, R.S., Porto, S.P.S., Whinery, J.R., (1965) J. Appl. Phys., 36, p. 3Andrade, A.A., Tenorio, E., Catunda, T., Baesso, M.L., Cassanho, A., Jenssen, H.P., (1999) J. Opt. Soc. Am. B, 16, p. 395Baesso, M.L., Bento, A.C., Andrade, A.A., Sampaio, J.A., Pecorato, E., Nunes, L.A.O., Catunda, T., Gama, S., (1998) Phys. Rev. B, 57, p. 10545Brown, S.M., Baesso, M.L., Shen, J., Snook, R.D., (1993) Anal. Chim. Acta, 282, p. 711Bento, A.C., Palangana, A.J., Evangelista, L.R., Baesso, M.L., Pereira, J.R.D., Da Silva, E.C., Mansanares, A.M., (1996) Appl. Phys. Lett., 68, p. 3371Pereira, J.R.D., Mansanares, A.M., Palangana, A.J., Baesso, M.L., (1999) Mol. Cryst. Liq. Cryst. Sci. Technol., Sect. A, 332, p. 3079Shen, J., Love, R.D., Snook, R.D., (1992) Chem. Phys., 165, p. 385Baesso, M.L., Shen, J., Snook, R.D., (1992) Chem. Phys. Lett., 197, p. 25

I Congreso internacional de la SECAH. Ex officina Hispana. Cádiz Mayo 2011

Acta del I Congreso Internacional de la Sociedad de Estudios de Cerámica antigua en Hispani

Determining the WIMP mass using the complementarity between direct and indirect searches and the ILC

We study the possibility of identifying dark matter properties from XENON-like 100 kg experiments and the GLAST satellite mission. We show that whereas direct detection experiments will probe efficiently light WIMPs, given a positive detection (at the 10% level for $m_{\chi} \lesssim 50$ GeV), GLAST will be able to confirm and even increase the precision in the case of a NFW profile, for a WIMP-nucleon cross-section $\sigma_{\chi-p} \lesssim 10^{-8}$ pb. We also predict the rate of production of a WIMP in the next generation of colliders (ILC), and compare their sensitivity to the WIMP mass with the XENON and GLAST projects.Comment: 32 pages, new figures and a more detailed statistical analysis. Final version to appear in JCA

Uncorrelated scattering approximation for the scattering and break-up of weakly bound nuclei on heavy targets

The scattering of a weakly bound (halo) projectile nucleus by a heavy target nucleus is investigated. A new approach, called the Uncorrelated Scattering Approximation, is proposed. The main approximation involved is to neglect the correlation between the fragments of the projectile in the region where the interaction with the target is important. The formalism makes use of hyper-spherical harmonics, Raynal-Revay coefficients and momentum-localized wave functions to expand projectile channel wave functions in terms of products of the channel wave function of the individual fragments. Within this approach, the kinetic energy and angular momentum of each fragment is conserved during the scattering process. The elastic, inelastic and break-up S-matrices are obtained as an analytic combination involving the bound wave function of the projectile and the product of the S-matrices of the fragments. The approach is applied to describe the scattering of deuteron on $^{58}$Ni at several energies. The results are compared with experimental data and continuum-discretized coupled-channels calculations.Comment: 34 pages, 5 figures, accepted for publication in Nucl. Phys.

Las termas y el Suburbium marítimo de Baelo Claudia. Avance de un reciente descubrimiento

Entre los años 2010 y 2012, la Universidad de Cádiz y la Junta de Andalucía han desarrollado investigaciones arqueológicas en la zona extramuros de la ciudad hispanorromana, en el marco del Proyecto General de Investigación “La economía marítima y las actividades haliéuticas en Baelo Claudia”. Se presentan en esta sede los primeros resultados, que han permitido identificar la existencia de un suburbium occidental en la ciudad, entre el cauce del arroyo de las Villas, la playa y la necrópolis oeste, cuya existencia se ha podido confirmar por datos geofísicos y arqueológicos. En él han podido ser excavadas parcialmente unas estructuras que se han identificado con unas termas suburbanas, activas entre el s. II y el V d.C., habiéndose excavado una piscina del frigidarium y algunas estancias calefactadas, con hallazgos muy significativos como parte de la decoración marmórea y escultórica del complejo, que en época tardorromana fue amortizado intencionalmente por motivos posiblemente religiosos. Estos hallazgos son de gran interés, pues además de verificar la existencia de un segundo complejo balneario público en la ciudad plantean la importancia del poblamiento periurbano, una línea de investigación totalmente inédita hasta la fechaBetween the year 2010 and 2012, the University of Cadiz and the Regional Government (Junta de Andalucía) have developed archaeological activities in the zone outside the hispano-roman city, in the frame of the General Project of Research titled “The maritime economy and the halieutic activities in Baelo Claudia”. We are presenting in this paper the first results, which have allowed to identify the existence of a western suburbium outside the city, between the riverbed of the so called “arroyo de las Villas”, the beach and the western necropolis, whose remains have been confirmed by geophysical and archaeological techniques. Inside this area a few structures have been excavated, identified as a Roman baths complex, active from the 2nd up to the 5th century a.D. A big pool, part of the frigidarium and some heated rooms have been unearthed, with very significant findings as part of the marmoreal and sculptural decoration of the complex, which in late roman times was intentionally broken into pieces possibly by religious motives. These findings are of great interest, since beside confirming the existence of the second public thermae of the city they raise the importance of the peri-urban buildings, a new line of research up to dat