A novel determination of the local dark matter density

We present a novel study on the problem of constructing mass models for the Milky Way, concentrating on features regarding the dark matter halo component. We have considered a variegated sample of dynamical observables for the Galaxy, including several results which have appeared recently, and studied a 7- or 8-dimensional parameter space - defining the Galaxy model - by implementing a Bayesian approach to the parameter estimation based on a Markov Chain Monte Carlo method. The main result of this analysis is a novel determination of the local dark matter halo density which, assuming spherical symmetry and either an Einasto or an NFW density profile is found to be around 0.39 GeV cm$^{-3}$ with a 1-$\sigma$ error bar of about 7%; more precisely we find a $\rho_{DM}(R_0) = 0.385 \pm 0.027 \rm GeV cm^{-3}$ for the Einasto profile and $\rho_{DM}(R_0) = 0.389 \pm 0.025 \rm GeV cm^{-3}$ for the NFW. This is in contrast to the standard assumption that $\rho_{DM}(R_0)$ is about 0.3 GeV cm$^{-3}$ with an uncertainty of a factor of 2 to 3. A very precise determination of the local halo density is very important for interpreting direct dark matter detection experiments. Indeed the results we produced, together with the recent accurate determination of the local circular velocity, should be very useful to considerably narrow astrophysical uncertainties on direct dark matter detection.Comment: 31 pages,11 figures; minor changes in the text; two figures adde

TRY plant trait database – enhanced coverage and open access

Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

Ages of evolved low mass stars: Central stars of planetary nebulae and white dwarfs

We have developed several methods to estimate the ages of central stars of planetary nebulae (CSPN), which are based either on observed nebular properties or on data from the stars themselves. Our goal is to derive the age distribution of these stars and compare the results with empirical distributions for CSPN and white dwarfs. We have initially developed three methods based on nebular abundances, using (i) an age-metallicity relation which is also a function of the galactocentric distance; (ii) an age-metallicity relation obtained for the galactic disk, and (iii) the central star masses derived from the observed nitrogen abundances. In this work we present two new, more accurate methods, which are based on kinematic properties: (I) in this method, the expected rotation velocities of the nebulae around the galactic centre at their galactocentric distances are compared with the predicted values for the galactic rotation curve, and the differences are attributed to the different ages of the evolved stars; (II) we determine directly the U, V, W, velocity components of the stars, as well as the velocity dispersions, and use the dispersion-age relation by the Geneva-Copenhagen survey. These methods were applied to two large samples of galactic CSPN. We conclude that most CSPN in the galactic disk have ages under 5 Gyr, and that the age distribution is peaked around 1 to 3 Gyr

Diagnosis Of A Compacted Area For Mining Through The Mechanical Resistance To The Penetration Using Geostatistical Methods In The Amazon Forest

The mining process promotes land modification and complete landscape alteration. Those alterations in the surface are shown more obviously in the aesthetical aspect as the visual elements of form, texture, climbs, complexity and color which composes the landscape. As a consequence, mining has impacts on the topography, in the soil, in the vegetation and in the area's drainage, with a direct influence on the enterprise. A quite common problem in the recovery of degraded areas in mineral exploration is the compaction of the soil due to the intense traffic of machines and earth movement. The most common problem of the compaction of a degraded surface is an increase of the mechanical resistance to the penetration of plant roots, a reduction of the aeration, an alteration of the flow of water and heat, also in the availability of water and nutrients. Thus, the present work had the basic objective of diagnosing the compaction of an area degraded by mining in a spacial way, through the mechanical resistance and the penetration, to guide the future subsoiling in the area requiring recovery. Through the studies, it was concluded that the krigagem method in agreement with the space variation allows the division of the area under study into sub areas facilitating a future work to reduce costs and unnecessary interference to the atmosphere. The method was shown to be quite appropriate and it can be used in the diagnosis of compaction in a degraded area by mining, foreseeing the subsoiling requirement.4149(1997) S313.2: Soil Cone Penetrometer, p. 2. , St Joseph, MIBrussard, L., Van Faassen, H.G., (1984) Effects of Compaction on Soil Biota and Soil Biological Processes. Soil Compaction in Croup Production, pp. 215-235. , London: ElsevierDe Camargo, O.A., Alleaoni, L.R.F., (1997) Compactação do Solo e o Desenvolvimento das Plantas, p. 132. , PiracicabaCambardella, C.A., Moorman, T.B., Novak, I.M., Parkin, T.B., Karlen, D.L., Turco, R.F., Konopka, A.E., Field-scale variability of soil properties in Central Iowa Soils (1994) Soil Science Society of America Journal, 58, pp. 1501-1511Canarache, A., Penetr-Generalized semi-empirical model estimating soil resistance to penetration (1990) Soil Till. Res., 16, pp. 56-70. , AmsterdamCarpanezzi, A.A., Costa, L.G.S., Kageyama, P.Y., Castro, C.F.A., Espécies pioneiras para recuperação de áreas degradadasobservações de laboratóries naturais (1990) Congresso Florestal Brasileiro, 60, pp. 216-221. , Campos do Jordão, AnaisFrança, J.T., (1991) Estudos da Sucessão Secundária em Áreas Contíguas a Mineração de Cassiterita na Floresta Nacional do Jamari-RO, p. 169. , Dissertação de mestrado apresentada a ESALQ/USP. Piracicaba(2002) GS+ Geostattistics for the Environmental Sciences, , http://www.gammadesign.com, 01 JulGuerra, P.A.G., (1988) Geoestatística Operacional, p. 145. , Brasilia: Ministério das Minas e Energia, Departamento de Produção MineralLal, R., Stewart, B.A., Need for land restoration (1992) Advanced in Soil Science, 17, pp. 1-9(1990) Manual de Recuperação de Áreas Degradadas pela Mineração:técnicas de Revegetação., , IBAMA. BrasíliaOdum, E.P., (1993) Ecology and Our Endangered Life-support Systems. 2nd. Ed.(1978) Radambrasil. Folha SC-20, p. 661. , Porto Velho. Rio de Janeiro, Departamento Nacional de Produção Mineral, (Levantamento de Recursos Naturais, 16)Saadi, A., Os sertões que viram desertes (2000) Boletim Informative. Sociedade Brasileira de Ciência do Solo, 25 (1), pp. 10-17. , Viçosa,MG. 2000Souza, J.A., (1997) Avaliação das Estratégias de Recuperação de Áreas Degradadas pela Mineração de Bauxita em Poços de Caldas (MG), p. 104. , Lavras: Universidade Federal de Lavras, (Tese de Doutorado)Trangmar, B.B., Yost, R.S., Uehara, G., Application of geostatistics to spatial studies of soil properties (1985) Advances in Soil Science, 38, pp. 45-94Warrick, A.W., Nielsen, D.R., Spacial variability of soil physical properties in the field (1980) Application of Soil Physic, 13, pp. 139-144. , Hilled, D. ed. New York: Academic Pres

Recovery Of Degraded Areas Using Topsoil In The Amazon Rainforest

This study is aimed at evaluating the effect of placing the top soil cover areas, such as tailings degraded by tin mining, in the Amazon rainforest in Brazil. The evaluations of the planting sites occurred in areas where tin mining was carried out, basically planting native trees over a period of seven years. This work did not come from a pre-decreed methodology of experimental design, and data was collected only seven years after planting. Thus, it was not possible to identify all variables that contributed to a better recovery of the areas. Sampling was done about seven years after placing the " top soil " and is determined: pH, organic matter content, P, K, Ca, Mg, Al, cation exchange capacity (T), base saturation (V%), B, Fe, Zn, Cu and Mn. The native forest species existing at the site were evaluated in relation to height (in meters) and diameter of the base. For all sites where the surface layer of soil was applied, there were significant differences in the growth of native species. A fundamental aspect in the rehabilitation of areas degraded by mining, in general, is the knowledge about the soil where that recovery must be conducted. The specific procedures in the rehabilitation of those areas depend essentially on the physical, chemical, biological and mineralogical properties of the soil, which must present conditions for the adequate development of the plants. The initial idea of implanting a project of recovery of soils degraded by mining in the Amazon Forest emerged from a first visit to the field, carried out in 1998. The conditions of the already mined areas, in comparison to the exuberant forest of the surroundings caught our attention. The mining company that acts in the area had already been trying for some time to implant a plan of recovery of these mining areas, however without reaching any significant positive results. The loss of organic matter is one of the main problems of degraded areas in Brazil. The storage and reuse of a blanket of soil (topsoil) produce excellent results, but most of the miners consider this technique expensive and difficult because of operational costs and the sharp topographical condition of the mine site. Therefore, a research project was elaborated prioritizing the recovery of the soil degraded by the tin mining as a prior step to the recovery activities with native forest species. The formation of a superficial pseudo-horizon that supported the vegetation and the time that it would take for its establishment became the main objective of this research. The objective of this work is to verify the levels of elements and their traces in areas where top soils were applied for the remediation of degraded areas with local re-vegetation. © 2011 WIT Press.167481485Fontes, M.P.F., Estudo pedológico reduz impacto da mineração (1991) Revista Da Cetesb De Tecnologia, pp. 58-61. , AMBIENTE, São PauloRibeiro, Admilson, I., (2005) Mecanização Do Preparo De Solo Em Áreas Degradadas Por Mineração Na Floresta Do Jamari, p. 135. , Rondônia, Brasil. FEAGRI, UNICAMP, Campinas-SP, (Tese de doutoradoVance, E.D., Brookes, P.C., Jenkinson, A.S., Na extraction method for measuring soil microbial biomass C (1982) Soil Biologic Biochemical, Oxford, 19, pp. 703-707Banzatto, D.A., Kronka, S.N., (1992) Experimentação Agrícola, p. 247. , 2.ed. Jaboticabal: Ed. Fune