The Galactic disk mass function: reconciliation of the HST and nearby determinations

We derive and parametrize the Galactic mass function (MF) below 1 \msol characteristic of both single objects and binary systems. We resolve the long standing discrepancy between the MFs derived from the HST and from the nearby luminosity functions, respectively. We show that this discrepancy stemmed from {\it two} cumulative effects, namely (i) incorrect color-magnitude determined distances, due a substantial fraction of M dwarfs in the HST sample belonging to the metal-depleted, thick-disk population, as corrected recently by Zheng et al. and (ii) unresolved binaries. We show that both the nearby and HST MF for unresolved systems are consistent with a fraction $\sim$50% of M-dwarf binaries, with the mass of both the primaries and the companions originating from the same underlying single MF. This implies that $\sim$30% of M dwarfs should have an M dwarf companion and $\sim$20% should have a brown dwarf companion, in agreement with recent determinations. The present calculations show that the so-called "brown-dwarf desert" should be reinterpreted as a lack of high mass-ratio (m_2/m_1\la 0.1) systems, and does not preclude a substantial fraction of brown dwarfs as companions of M dwarfs or for other brown dwarfs.Comment: 16 pages, Latex file, uses aasms4.sty, to appear in ApJ Letter

Caracterización química, perfil de ácidos grasos y actividad antioxidante del mesocarpio de la fruta Gustavia macarenensis y su aceite de la región amazónica de Ecuador como fuente no convencional de aceite vegetal

To our knowledge, this study is the first to report on the nutritional characterization, bioactive compounds and antioxidant activity of Amazonian G. macarenensis fruit. The fatty acid profile was determined using a high performance liquid chromatography analysis. The total phenolic content and antioxidant activity were determined using Folin Ciocalteu’s method and by radical scavenging activity, respectively. Moreover, a cluster analysis was carried out in order to classify the G. macarenensis fruit oil according to its fatty acid profile. Seven Fisher linear discriminant functions were obtained from the discriminant analysis. These models allow one to classify new fruits on the basis of their fatty acid profile. A high value for total lipids was obtained (53.57%). Its main components were palmitic and oleic acid. The TPC value (156.49 ± 2.62 mg GAE/Kg of oil) obtained from the G. macarenensis fruit pulp oil is higher than what was reported for some olive oil and Brazilian mango oil varieties.Hasta donde sabemos, este estudio sería el primero sobre la caracterización nutricional, los compuestos bioactivos y la actividad antioxidante de la fruta amazónica G. macarenensis. El perfil de ácidos grasos se determinó mediante análisis de cromatografía líquida de alta resolución. El contenido fenólico total y la actividad antioxidante se determinaron utilizando el método de Folin Ciocalteu y la medida de la actividad de eliminación de radicales, respectivamente. Además, se realizó un análisis de conglomerados para clasificar el aceite de fruta G. macarenensis según su perfil de ácidos grasos. Se obtuvieron siete funciones discriminantes lineales de Fisher a partir del análisis discriminante. Estos modelos permiten clasificar frutas nuevas en función de su perfil de ácidos grasos. Se obtuvo un alto valor para el total de lípidos (53.57%). Sus componentes principales son los ácidos palmítico y oleico. El valor TPC (156.49 ± 2.62 mg GAE/Kg de aceite) obtenido del aceite de pulpa de fruta de G. macarenensis es más alto que el que se reporta para algunas variedades de aceite de oliva y aceite de mango brasileño

Datos sobre la vegetación del centro del Perú

Datos sobre la vegetación del centro del Perú. El presente artículo trata de aportar algunas novedades fitosociológicas sobre los valles centrales del Departamento de Lima (Perú). Como resultado de los inventarios fitosociológicos levantados en los valles de Santa Eulalia, Rimac, Chillón y San Bartolomé, se describen 6 asociaciones (Baccharido salicifoliae-Gynerietum sagittati, Equiseto gigantei-Salicetum humboldtianae, Caricetum candicantis, Matucano haynei-Tillandsietum humilis, Aristeguietio discoloris-Baccharidetum latifoliae y Jungietum axillaris), 3 alianzas (Pityrogrammo trifoliatae-Baccharidion salicifoliae, Adiantion poiretii y Jungion axillaris) y 1 orden (Baccharidetalia salicifoliae). Además se comentan 5 nuevas subasociaciones, 5 comunidades y algunos aspectos fragmentarios de la vegetación (comunidades basales, BC y comunidades derivadas, DC). También se presenta un mapa preliminar de las series de vegetación en el centro del Perú (Departamento de Lima)

Assertion-based Analysis via Slicing with ABETS

[EN] We present ABETS, an assertion-based, dynamic analyzer that helps diagnose errors in Maude programs. ABETS uses slicing to automatically create reduced versions of both a run's execution trace and executed program, reduced versions in which any information that is not relevant to the bug currently being diagnosed is removed. In addition, ABETS employs runtime assertion checking to automate the identification of bugs so that whenever an assertion is violated, the system automatically infers accurate slicing criteria from the failure. We summarize the main services provided by ABETS, which also include a novel assertionbased facility for program repair that generates suitable program fixes when a state invariant is violated. Finally, we provide an experimental evaluation that shows the performance and effectiveness of the system.This work has been partially supported by the EU (FEDER) and Spanish MINECO grant TIN2015-69175-C4-1-R, and by Generalitat Valenciana PROMETEOII/2015/013. J. Sapina was supported by FPI-UPV grant SP2013-0083.Alpuente Frasnedo, M.; Frechina, F.; Sapiña Sanchis, J.; Ballis, D. (2016). Assertion-based Analysis via Slicing with ABETS. Theory and Practice of Logic Programming. 16(5):515-532. https://doi.org/10.1017/S1471068416000375S51553216

Exploiting Term Hiding to Reduce Run-time Checking Overhead

One of the most attractive features of untyped languages is the flexibility in term creation and manipulation. However, with such power comes the responsibility of ensuring the correctness of these operations. A solution is adding run-time checks to the program via assertions, but this can introduce overheads that are in many cases impractical. While static analysis can greatly reduce such overheads, the gains depend strongly on the quality of the information inferred. Reusable libraries, i.e., library modules that are pre-compiled independently of the client, pose special challenges in this context. We propose a technique which takes advantage of module systems which can hide a selected set of functor symbols to significantly enrich the shape information that can be inferred for reusable libraries, as well as an improved run-time checking approach that leverages the proposed mechanisms to achieve large reductions in overhead, closer to those of static languages, even in the reusable-library context. While the approach is general and system-independent, we present it for concreteness in the context of the Ciao assertion language and combined static/dynamic checking framework. Our method maintains the full expressiveness of the assertion language in this context. In contrast to other approaches it does not introduce the need to switch the language to a (static) type system, which is known to change the semantics in languages like Prolog. We also study the approach experimentally and evaluate the overhead reduction achieved in the run-time checks.Comment: 26 pages, 10 figures, 2 tables; an extension of the paper version accepted to PADL'18 (includes proofs, extra figures and examples omitted due to space reasons

Porosities and dimensions of measures

We introduce a concept of porosity for measures and study relations between dimensions and porosities for two classes of measures: measures on $R^n$ which satisfy the doubling condition and strongly porous measures on $R$.Comment: Jarvenpaa = J\"arvenp\"a\"

The mass surface density in the local disk and the chemical evolution of the Galaxy

We have studied the effect of adopting different values of the total baryonic mass surface density in the local disk at the present time in a model for the chemical evolution of the Galaxy. We have compared our model results with the G-dwarf metallicity distribution, the amounts of gas, stars, stellar remnants, infall rate and SN rate in the solar vicinity, and with the radial abundance gradients and gas distribution in the disk. This comparison strongly suggests that the value of the total baryonic mass surface density in the local disk which best fits the observational properties should lie in the range 50-75 Msun pc-2, and that values outside this range should be ruled out.Comment: 6 pages, LaTeX, 3 figures, accepted for publication in the Astrophysical Journal, uses emulateapj.st

Microlensing optical depth towards the Galactic bulge from MOA observations during 2000 with Difference Image Analysis

We analyze the data of the gravitational microlensing survey carried out by by the MOA group during 2000 towards the Galactic Bulge (GB). Our observations are designed to detect efficiently high magnification events with faint source stars and short timescale events, by increasing the the sampling rate up to 6 times per night and using Difference Image Analysis (DIA). We detect 28 microlensing candidates in 12 GB fields corresponding to 16 deg^2. We use Monte Carlo simulations to estimate our microlensing event detection efficiency, where we construct the I-band extinction map of our GB fields in order to find dereddened magnitudes. We find a systematic bias and large uncertainty in the measured value of the timescale $t_{\rm Eout}$ in our simulations. They are associated with blending and unresolved sources, and are allowed for in our measurements. We compute an optical depth tau = 2.59_{-0.64}^{+0.84} \times 10^{-6} towards the GB for events with timescales 0.3<t_E<200 days. We consider disk-disk lensing, and obtain an optical depth tau_{bulge} = 3.36_{-0.81}^{+1.11} \times 10^{-6}[0.77/(1-f_{disk})] for the bulge component assuming a 23% stellar contribution from disk stars. These observed optical depths are consistent with previous measurements by the MACHO and OGLE groups, and still higher than those predicted by existing Galactic models. We present the timescale distribution of the observed events, and find there are no significant short events of a few days, in spite of our high detection efficiency for short timescale events down to t_E = 0.3 days. We find that half of all our detected events have high magnification (>10). These events are useful for studies of extra-solar planets.Comment: 65 pages and 30 figures, accepted for publication in ApJ. A systematic bias and uncertainty in the optical depth measurement has been quantified by simulation