A multi-scale distribution model for non-equilibrium populations suggests resource limitation in an endangered rodent.

Species distributions are known to be limited by biotic and abiotic factors at multiple temporal and spatial scales. Species distribution models, however, frequently assume a population at equilibrium in both time and space. Studies of habitat selection have repeatedly shown the difficulty of estimating resource selection if the scale or extent of analysis is incorrect. Here, we present a multi-step approach to estimate the realized and potential distribution of the endangered giant kangaroo rat. First, we estimate the potential distribution by modeling suitability at a range-wide scale using static bioclimatic variables. We then examine annual changes in extent at a population-level. We define available habitat based on the total suitable potential distribution at the range-wide scale. Then, within the available habitat, model changes in population extent driven by multiple measures of resource availability. By modeling distributions for a population with robust estimates of population extent through time, and ecologically relevant predictor variables, we improved the predictive ability of SDMs, as well as revealed an unanticipated relationship between population extent and precipitation at multiple scales. At a range-wide scale, the best model indicated the giant kangaroo rat was limited to areas that received little to no precipitation in the summer months. In contrast, the best model for shorter time scales showed a positive relation with resource abundance, driven by precipitation, in the current and previous year. These results suggest that the distribution of the giant kangaroo rat was limited to the wettest parts of the drier areas within the study region. This multi-step approach reinforces the differing relationship species may have with environmental variables at different scales, provides a novel method for defining available habitat in habitat selection studies, and suggests a way to create distribution models at spatial and temporal scales relevant to theoretical and applied ecologists

Study of basic bio-electrochemistry Sixth monthly progress report, 1-31 Aug. 1963

Contribution of hydrogen peroxide to electrode reaction in electrochemical cell by considering effect of catalyst on cell curren

Superconductor strip in a closed magnetic environment: exact analytic representation of the critical state

An exact analytic representation of the critical state of a current-carrying type-II superconductor strip located inside a cylindrical magnetic cavity of high permeability is derived. The obtained results show that, when the cavity radius is small, penetration of magnetic flux fronts is strongly reduced as compared to the situation in an isolated strip. From our generic representation it is possible to establish current profiles in closed cavities of various other geometries too by means of conformal mapping of the basic configuration addressed.Comment: 2 pages, 1 figure; accepted in Physica C for the Proceedings of M2S-HTSC, Dresden, 200

A framework to combine low- and high-resolution spectroscopy for the atmospheres of transiting exoplanets

Current observations of the atmospheres of close-in exoplanets are predominantly obtained with two techniques: low-resolution spectroscopy with space telescopes and high-resolution spectroscopy from the ground. Although the observables delivered by the two methods are in principle highly complementary, no attempt has ever been made to combine them, perhaps due to the different modeling approaches that are typically used in their interpretation. Here we present the first combined analysis of previously-published dayside spectra of the exoplanet HD 209458b obtained at low resolution with HST/WFC3 and Spitzer/IRAC, and at high resolution with VLT/CRIRES. By utilizing a novel retrieval algorithm capable of computing the joint probability distribution of low- and high-resolution spectra, we obtain tight constraints on the chemical composition of the planet's atmosphere. In contrast to the WFC3 data, we do not confidently detect H2O at high spectral resolution. The retrieved water abundance from the combined analysis deviates by 1.9 sigma from the expectations for a solar-composition atmosphere in chemical equilibrium. Measured relative molecular abundances of CO and H2O strongly favor an oxygen-rich atmosphere (C/O<1 at 3.5 sigma) for the planet when compared to equilibrium calculations including O rainout. From the abundances of the seven molecular species included in this study we constrain the planet metallicity to 0.1-1.0x the stellar value (1 sigma). This study opens the way to coordinated exoplanet surveys between the flagship ground- and space-based facilities, which ultimately will be crucial for characterizing potentially-habitable planets.Comment: 7 pages, 5 figures, accepted for publication in ApJL. Section 4 largely updated from previous version, Figure 2 updated to contain information on the T-p profil

The iron ore deposits of Ulu Rompin, Malaya

The Ulu Rompin iron deposits are located in an area of rugged topography in the State of Pahang, Malaya. There are several high grade primary ore bodies and superficial sheets of lateritic ore. The area is underlain by sheared alkalic rhyolite lavas and tuffs in which there are small lenses of sedimentary rocks, carbonates being the most important. There are several small stocks of hornblende granodiorite which probably merge into one larger parental mass at depth. The Bt Ibam ore body, which is the largest, is a tabular mass of magnetite in a highly magnesian gangue, originally chlorite and actinolite but now largely altered to talc. Underneath the ore there is a thin intermittent layer of calcic skarn, while massive chlorite appears along parts of the hanging wall. A short distance below the footwall there is granodiorite. The Bt. Batu Puteh deposit is magnetite associated with calcite marble, and at Bt. Hitam magnetite is found just above granodiorite. At Bt. Pesagi and BT. Sanlong the primary ore is haematite with very little magnetite. These bodies are located in shear zones in the volcanic rocks, and are not associated with calcic or magnesian minerals. All the ore bodies and country rocks have been pyritized, and other sulphides and sulphosalts have impregnated the Bt. Ibam body. These have produced zones, contaminated by copper and zinc, and to a lesser degree bismuth and lead. Hypogene and supergene alteration have extensively affected the iron ores and rocks and caused some redistribution of the impurity elements. The iron ores probably originated in the cooling granodiorite magma and were transported as chlorides or chloride complexes. The control over the loci of mineralization was partly lithological - magnetite bodies in calcic and magnesian rocks, and partly structural - haematite bodies in shear zones