José F. Gómez

A GLOBAL EVALUATION OF METABOLIC THEORY AS AN EXPLANATION FOR TERRESTRIAL SPECIES RICHNESS GRADIENTS

We compiled 46 broadscale data sets of species richness for a wide range of terrestrial plant, invertebrate, and ectothermic vertebrate groups in all parts of the world to test the ability of metabolic theory to account for observed diversity gradients. The theory makes two related predictions: (1) In-transformed richness is linearly associated with a linear, inverse transformation of annual temperature, and (2) the slope of the relationship is near -0.65. Of the 46 data sets, 14 had no significant relationship; of the remaining 32, nine were linear, meeting prediction 1. Model I (ordinary least squares, OLS) and model II (reduced major axis, RMA) regressions then tested the linear slopes against prediction 2. In the 23 data sets having nonlinear relationships between richness and temperature, split-line regression divided the data into linear components, and regressions were done on each component to test prediction 2 for subsets of the data. Of the 46 data sets analyzed in their entirety using OLS regression, one was consistent with metabolic theory (meeting both predictions), and one was possibly consistent. Using RMA regression, no data sets were consistent. Of 67 analyses of prediction 2 using OLS regression on all linear data sets and subsets, two were consistent with the prediction, and four were possibly consistent. Using RMA regression, one was consistent (albeit weakly), and four were possibly consistent. We also found that the relationship between richness and temperature is both taxonomically and geographically conditional, and there is no evidence for a universal response of diversity to temperature. Meta-analyses confirmed significant heterogeneity in slopes among data sets, and the combined slopes across studies were significantly lower than the range of slopes predicted by metabolic theory based on both OLS and RMA regressions. We conclude that metabolic theory, as currently formulated, is a poor predictor of observed diversity gradients in most terrestrial systems.

Radio Continuum-H2O Maser Systems in NGC 2071: H2O Masers Tracing a Jet (IRS 1) and a Rotating Proto-Planetary Disk of Radius 20 AU (IRS 3)

We have observed simultaneously the 1.3 cm continuum and H2O maser emission toward the core of the star-forming region NGC 2071 using the Very Large Array in its A configuration. Two 1.3 cm continuum sources have been detected in the region, coinciding with the infrared sources IRS 1 and IRS 3, respectively. The radio emission in IRS 3 is consistent with an ionized thermal bipolar radio jet. Two clusters of H2O maser spots are detected, one associated with IRS 1 (22 spots) and the other one associated with IRS 3 (13 spots). The H2O maser distribution in IRS 1 seems to be tracing at scales of 300 AU the larger scale H2 outflow observed at a few thousands of AU from the exciting source. On the other hand, the H2O masers in IRS 3 are distributed as an apparent disk of 005 (20 AU) radius, oriented almost perpendicular to the major axis of the radio jet. There is a clear velocity gradient (0.35 km s-1 AU-1) along the major axis of the H2O maser distribution, which can be gravitationally bound by a central mass of 1 M☉. These results, together with the low-mass and early evolutionary stage of IRS 3, suggest that masers around this source are tracing a rotating proto-planetary disk within a proto-solar-like system. This represents direct kinematic evidence of the smallest rotating circumstellar disk ever observed around a young stellar object (YSO). We discuss the dichotomy of H2O masers tracing either outflows or disks around YSOs, based on the evolutionary scheme proposed in our earlier work. We suggested that systems in which H2O masers trace disks are less evolved than those in which masers trace outflows. In this scheme, IRS 3 would then represent a relatively less evolved object than IRS 1. This prediction is consistent with independent infrared observations showing that IRS 3 is at an earlier phase of evolution.

The Thermal Radio Jet of Cepheus A HW2 and the Water Maser Distribution at 0.″08 Scale (60 AU)

We report observations of the thermal radio jet in Cepheus A HW2, and the associated water masers, carried out with the highest (008) angular resolution available to date at the VLA (A configuration at λ = 1.3 cm). To calibrate the 1.3 cm continuum emission, we used the strong (~1000 Jy) H2O maser source as the reference, thus correcting the amplitude and phase instabilities introduced by the atmosphere. This powerful technique, first applied here to a star-forming region, allowed us to achieve a dynamic range of 15,000:1 for the strongest maser feature, a signal-to-noise ratio (S/N) of 70:1 for the radio jet and an accuracy of the order of 1 mas in the relative positions between the radio-continuum jet and the H2O masers in the region. We resolved the 1.3 cm jet into two maxima plus a fainter tail to the southwest. The separation between these two maxima (014) and the total size of the jet (039) are both consistent with models for a biconical ionized jet. The observed flux density (39 mJy) is, however, higher than expected. We detected 39 H2O maser spots toward the Cepheus A region, 28 of which are associated with the HW2 object, most of them distributed on either sides of the radio jet. We suggest that these latter maser features might be tracing a circumstellar molecular disk of radius ~300 AU, nearly perpendicular to the radio jet. The velocity gradient of 30 ± 10 km s-1 observed in the H2O spots over 600 AU along the axis perpendicular to the radio jet could be gravitationally bound by a central mass of 70 ± 40 M☉.

Challenging species distribution models : the case of Maculinea nausithous in the Iberian Peninsula

Maculinea nausithousis the most endangered Iberian butterfly, being included in the Bern and Habitat directives and in the Spanish Red Book for invertebrates. We map its potential distribution in the Iberian Peninsula, identifying potentially suitable areas where to focus future surveys. Using presence/absence data and a set of environmental variables, the distribution of M. nausithous was modelled using Generalized Additive Models. Model results were filtered using land cover data to identify the anthropogenic grasslands inhabited by the species. The model obtained indicates that some Iberian areas that currently do not support M. nausithous populations could be environmentally suitable for the species. The reasons for these absences are discussed. Indeed, field surveys identified possible sources of uncertainty at finer scale, highlighting that deficiencies in land use GIS data might constitute an important source of error, able to explain both commission and omission errors (i.e., over and underpredictions) of the model.

The molecular cores in the L1287, AFGL 5142, and IRAS 20126 + 4104 regions

The NH 3 (J, K)=(1, 1) and (2, 2) line emission was mapped toward three regions with molecular outflows, L1287, AFGL 5142, and IRAS 20126+4104, using the Effelsberg 100 m telescope. Additional C 18 O (J=2→1) and CS (J=3→2) observations of L1287 were carried out with the IRAM 30 m telescope. For the three regions, the high-density molecular core, as traced by the ammonia emission, peaks very close to the position of the proposed powering sources of the outflows. In AFGL 5142 we flavor the radio continuum source proposed by Torrelles et al. (1992b) as the powering source of the outflow. The molecular cores best resolved by the telescope beam are elongated in a direction perpendicular to the outflow axis

On the nature of the excitation of Herbig-Haro object 2

VLA observations of the NH 3 (1, 1) and NH 3 (2, 2) lines toward the HH 2 object using the D configuration are presented. Several small (∼20) clumps located near HH 2 are detected. These clumps are cold, T R (2, 2; 1, 1) ≤20 k, and with narrow line widths, ΔV ≤ 1 km/s. It is found that these clumps appear a few arcseconds downwind with respect to the HH 2 optical knots and the H 2 [S(1), v = 1→0] line emission. The low temperatures and narrow line widths found in the ammonia clumps imply that they cannot be ambient clump compressed as a whole by a shock wave

Imaging the inner and outer gaps of the pre-transitional disk of HD 169142 at 7 mm

We present Very Large Array observations at 7 mm that trace the thermal emission of large dust grains in the HD 169142 protoplanetary disk. Our images show a ring of enhanced emission of radius ∼25-30 AU, whose inner region is devoid of detectable 7 mm emission. We interpret this ring as tracing the rim of an inner cavity or gap, possibly created by a planet or a substellar companion. The ring appears asymmetric, with the western part significantly brighter than the eastern one. This azimuthal asymmetry is reminiscent of the lopsided structures that are expected to be produced as a consequence of trapping of large dust grains. Our observations also reveal an outer annular gap at radii from ∼40 to ∼70 AU. Unlike other sources, the radii of the inner cavity, the ring, and the outer gap observed in the 7 mm images, which trace preferentially the distribution of large (millimeter/centimeter sized) dust grains, coincide with those obtained from a previous near-infrared polarimetric image, which traces scattered light from small (micron-sized) dust grains. We model the broadband spectral energy distribution and the 7 mm images to constrain the disk physical structure. From this modeling we infer the presence of a small (radius ∼0.6 AU) residual disk inside morexa0» the central cavity, indicating that the HD 169142 disk is a pre-transitional disk. The distribution of dust in three annuli with gaps in between them suggests that the disk in HD 169142 is being disrupted by at least two planets or substellar objects. «xa0less

The powering sources of the molecular outflows in the AFGL 437, AFGL 5142, and AFGL 5157 regions

VLA 3.6 cm continuum and water maser observations are presented toward the central region of three molecular outflows for which the position of the powering sources was not clearly established: AFGL 437, AFGL 5142, and AFGL 5157. In these regions, continuum and H 2 O maser emission has been detected near the peak of the associated high-density molecular cores. These data indicate a close association between the molecular cores, the radio continuum sources, and the H 2 O masers

IRAS 18113–2503: THE WATER FOUNTAIN WITH THE FASTEST JET?

We present Expanded Very Large Array water maser observations at 22 GHz toward the source IRAS 18113-2503. Maser components span over a very high velocity range of {approx_equal} 500 km s{sup -1}, the second largest found in a Galactic maser, only surpassed by the high-mass star-forming region W49N. Maser components are grouped into a blueshifted and a redshifted cluster, separated by 0.12. Further mid-IR and radio data suggest that IRAS 18113-2503 is a post-asymptotic giant branch star, thus a new bona fide member of the rare class of water fountains (WFs). It is the evolved object with the largest total velocity spread in its water masers and with the highest velocity dispersion within its redshifted and blueshifted lobes ({approx_equal} 170 km s{sup -1}). The large total velocity range of emission probably indicates that IRAS 18113-2503 has the fastest jet among the known WF stars. On the other hand, the remarkably high velocity dispersion within each lobe may be interpreted in terms of shocks produced by an episode of mass ejection whose velocity increased up to very high values or, alternatively, by projection effects in a jet with a large opening angle and/or precessing motions.

Which leaf beetles have not yet been described? Determinants of the description of Western Palaearctic Aphthona species (Coleoptera: Chrysomelidae)

The degree of completeness of the western Palaearctic inventory of the genus Aphthona and the factors that have determined the process of species description in the region were analysed. The historic species accumulation curve shows no asymptotic trend so no accurate estimations could be made of the number of species to be discovered in the future, but the shape of the curve indicates that a significant proportion of the taxa remains yet-to-be-described and thus further taxonomic effort will be needed. In order to optimise this taxonomic work, several morphologic, trophic and geographic variables of Aphthona species were analysed, in a search for the factors that have influenced the probability of discovery of taxa and thus to estimate the characteristics of the yet-to-be-described species. General Regression Models and variation partitioning were used to assess the influence on the process of species description of body size and colour, trophic range, number of host plants, geographic range size, maximum and minimum latitude and longitude. Morphological variables are not statistically significant in explaining the variation in the year of description, whereas trophic and geographic variables are essential determinants. The pure effects of geographic range size, trophic variables and geographic location of taxa are negligible, but the shared effects between the three groups of variables account for important portions of the variation; the whole model explains 64% of the variance. Widely distributed and trophic generalist species living in northern and western areas of the western Palaearctic region were described first. Extrapolation of the observed pattern should yield an estimate of the probable features and location of the yet-to-be-described species. New Aphthona should be searched for southwards and eastwards, distributed in small areas and living on a single, or very few, host plants.