Generalizations of Ripley's K-function with Application to Space Curves

The intensity function and Ripley's K-function have been used extensively in the literature to describe the first and second moment structure of spatial point sets. This has many applications including describing the statistical structure of synaptic vesicles. Some attempts have been made to extend Ripley's K-function to curve pieces. Such an extension can be used to describe the statistical structure of muscle fibers and brain fiber tracks. In this paper, we take a computational perspective and construct new and very general variants of Ripley's K-function for curves pieces, surface patches etc. We discuss the method from [Chiu, Stoyan, Kendall, & Mecke 2013] and compare it with our generalizations theoretically, and we give examples demonstrating the difference in their ability to separate sets of curve pieces.Comment: 9 pages & 8 figure

The Search for the Missing Baryons at Low Redshift

At low redshift, only about one-tenth of the known baryons lie in galaxies or the hot gas seen in galaxy clusters and groups. Models posit that these "missing baryons" are in gaseous form in overdense filaments that connect the much denser virialized groups and clusters. About 30% are cool (<1E5 K) and are detected in Ly alpha absorption studies, but about half is predicted to lie in the 1E5-1E7 K regime. Gas is detected in the 2-5E5 K range through OVI absorption studies (7% of the baryons) and possibly near 1E5 K from broad Ly absorption (20% of the baryons). Hotter gas (0.5-2E6 K) is detected at zero redshift by OVII and OVIII K X-ray absorption, and the OVII line strengths seem to correlate with the Galactic soft X-ray background, so it is probably produced by Galactic Halo gas, rather than a Local Group medium. There are no compelling detections of the intergalactic hot gas (0.5-10E6 K) either in absorption or emission and these upper limits are consistent with theoretical models. Claimed X-ray absorption lines are not confirmed, while most of the claims of soft emission are attributable to artifacts of background subtraction and field-flattening. The missing baryons should become detectable with moderate improvements in instrumental sensitivity.Comment: To appear in Annual Review of Astronomy and Astrophysics, Vol 45 (Sept 2007) 44 pages, including 11 figure

Electronic prescribing - how does it affect the ward pharmacist?

It is likely that electronic prescribing will be a common feature in tomorrow’s hospitals. However, we do not yet know how its introduction will affect the practice of hospital pharmacists. We are evaluating a closed-loop electronic prescribing, automated dispensing, bar-coded administration system (ServeRx) on one surgical ward. As part of this evaluation, we wanted to explore its impact on the ward pharmacist. Our objectives were to assess the impact of ServeRx on the time spent providing a ward pharmacy service, and on the activities undertaken

Dark Matter at the Center and in the Halo of the Galaxy

All presently known stellar-dynamical constraints on the size and mass of the supermassive compact dark object at the Galactic center are consistent with a ball of self-gravitating, nearly non-interacting, degenerate fermions with mass between 76 and 491 keV, for degeneracy factor g=2. Sterile neutrinos of 76 keV mass, which are mixed with at least one of the active neutrinos with a mixing angele ~10^{-7}, are produced in about the right amount in the early Universe by incoherent resonant and non-resonant scattering of active neutrinos having asymmetry of ~0.01. The former process yields sterile neutrinos with a quasi-degenerate spectrum while the latter leads to a thermal spectrum. As the production mechanism of the sterile neutrino is consistent with the constraints from large scale structure formation, core collapse supernovae, and diffuse X-ray background, it could be the dark matter particle of the Universe.Comment: 6 pages, to appear in the Beyond 2003 conference proceeding

Dense Packings of Congruent Circles in Rectangles with a Variable Aspect Ratio

We use computational experiments to find the rectangles of minimum area into which a given number n of non-overlapping congruent circles can be packed. No assumption is made on the shape of the rectangles. Most of the packings found have the usual regular square or hexagonal pattern. However, for 1495 values of n in the tested range n =< 5000, specifically, for n = 49, 61, 79, 97, 107,... 4999, we prove that the optimum cannot possibly be achieved by such regular arrangements. The evidence suggests that the limiting height-to-width ratio of rectangles containing an optimal hexagonal packing of circles tends to 2-sqrt(3) as n tends to infinity, if the limit exists.Comment: 21 pages, 13 figure

The application of self-limiting transgenic insects in managing resistance in experimental metapopulations

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.Data sharing: raw data for this study are available as supplementary data files.1. The mass release of transgenic insects carrying female lethal self-limiting genes can reduce pest insect populations. Theoretically, substantial releases can be a novel resistance management tool, since wild type alleles conferring susceptibility to pesticides can dilute resistance alleles in target populations. A potential barrier to the deployment of this technology is the need for large-scale area wide releases. Here we address whether localized releases of transgenic insects could provide an alternative, means of population suppression and resistance management, without serious loss of efficacy. 2. We used experimental mesocosms constituting insect metapopulations to explore the evolution of resistance to the Bacillus thuringiensis toxin Cry1Ac in a high-dose/refugia landscape in the insect Plutella xylostella. We ran two selection experiments, the first compared the efficacy of ‘everywhere’ releases and negative controls to a spatially density-dependent or ‘whack-a-mole’ strategy that concentrated release of transgenic insects in sub-populations with high levels of resistance. The second experiment tested the relative efficacy of whack-a-mole and everywhere releases under spatially homogenous and heterogeneous selection pressure. 3. The whack-a-mole releases were less effective than everywhere releases in terms of slowing the evolution of resistance, which in the first experiment, largely prevented the evolution of resistance. In contrast to predictions, heterogeneous whack-a-mole releases were not more effective under heterogeneous selection pressure. Heterogeneous selection pressure did, however, reduce total insect population sizes 4. Whack-a-mole releases provided early population suppression that was indistinguishable from homogeneous everywhere releases. However, insect population densities tracked the evolution of resistance in this system, as phenotypic resistance provides access to the 90% of experimental diet containing the toxin Cry1Ac. Thus, as resistance levels diverged between treatments, carrying capacities diverged and population sizes increased under the whack- a-mole approach. Synthesis and Applications Spatially density-dependent releases of transgenic insects, particularly those targeting source populations at landscape level, could suppress pest populations in the absence of blanket area-wide management. The resistance management benefits of self-limiting transgenic insects are, however, reduced in spatially localized releases, suggesting that they are not best suited for spatially restricted ‘spot’ treatment of problematic resistance. Nevertheless, area-wide and spatially heterogeneous releases could be used to support other resistance management interventions.This work was supported by the Biotechnology and Biological Sciences Research Council [grant numbers BB/L00948X/1 to MBB and NA, and BB/L00819X/1&2 to BR]

The carbon cycle in Mexico: past, present and future of C stocks and fluxes

PublishedThe Supplement related to this article is available online at doi:10.5194/bg-13-223-2016-supplement.We modeled the carbon (C) cycle in Mexico with a process-based approach. We used different available products (satellite data, field measurements, models and flux towers) to estimate C stocks and fluxes in the country at three different time frames: present (defined as the period 2000–2005), the past century (1901–2000) and the remainder of this century (2010–2100). Our estimate of the gross primary productivity (GPP) for the country was 2137 ± 1023 TgC yr−1 and a total C stock of 34 506 ± 7483 TgC, with 20 347 ± 4622 TgC in vegetation and 14 159 ± 3861 in the soil. Contrary to other current estimates for recent decades, our results showed that Mexico was a C sink over the period 1990–2009 (+31 TgC yr−1) and that C accumulation over the last century amounted to 1210 ± 1040 TgC. We attributed this sink to the CO2 fertilization effect on GPP, which led to an increase of 3408 ± 1060 TgC, while both climate and land use reduced the country C stocks by −458 ± 1001 and −1740 ± 878 TgC, respectively. Under different future scenarios, the C sink will likely continue over the 21st century, with decreasing C uptake as the climate forcing becomes more extreme. Our work provides valuable insights on relevant driving processes of the C cycle such as the role of drought in drylands (e.g., grasslands and shrublands) and the impact of climate change on the mean residence time of soil C in tropical ecosystems.The lead author (G. Murray-Tortarolo) thanks CONACYT-CECTI, the University of Exeter and Secretaría de Educación Pública (SEP) for their funding of this project. The authors extend their thanks to Carlos Ortiz Solorio and to the Colegio de Posgraduados for the field soil data and to the Alianza Redd+ Mexico for the field biomass data. This project would not have been possible without the valuable data from the CMIP5 models. A. Arneth, G. Murray-Tortarolo, A. Wiltshire and S. Sitch acknowledge the support of the European Commission-funded project LULCC4C (grant no. 603542). A. Wiltshire was partsupported by the Joint UK DECC/Defra Met Office Hadley Centre Climate Programme (GA01101)

Expressing Measurement Uncertainty in OCL/UML Datatypes

Uncertainty is an inherent property of any measure or estimation performed in any physical setting, and therefore it needs to be considered when modeling systems that manage real data. Although several modeling languages permit the representation of measurement uncertainty for describing certain system attributes, these aspects are not normally incorporated into their type systems. Thus, operating with uncertain values and propagating uncertainty are normally cumbersome processes, di cult to achieve at the model level. This paper proposes an extension of OCL and UML datatypes to incorporate data uncertainty coming from physical measurements or user estimations into the models, along with the set of operations de ned for the values of these types.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Mangarara Formation: exhumed remnants of a middle Miocene, temperate carbonate, submarine channel-fan system on the eastern margin of Taranaki Basin, New Zealand

The middle Miocene Mangarara Formation is a thin (1–60 m), laterally discontinuous unit of moderately to highly calcareous (40–90%) facies of sandy to pure limestone, bioclastic sandstone, and conglomerate that crops out in a few valleys in North Taranaki across the transition from King Country Basin into offshore Taranaki Basin. The unit occurs within hemipelagic (slope) mudstone of Manganui Formation, is stratigraphically associated with redeposited sandstone of Moki Formation, and is overlain by redeposited volcaniclastic sandstone of Mohakatino Formation. The calcareous facies of the Mangarara Formation are interpreted to be mainly mass-emplaced deposits having channelised and sheet-like geometries, sedimentary structures supportive of redeposition, mixed environment fossil associations, and stratigraphic enclosure within bathyal mudrocks and flysch. The carbonate component of the deposits consists mainly of bivalves, larger benthic foraminifers (especially Amphistegina), coralline red algae including rhodoliths (Lithothamnion and Mesophyllum), and bryozoans, a warm-temperate, shallow marine skeletal association. While sediment derivation was partly from an eastern contemporary shelf, the bulk of the skeletal carbonate is inferred to have been sourced from shoal carbonate factories around and upon isolated basement highs (Patea-Tongaporutu High) to the south. The Mangarara sediments were redeposited within slope gullies and broad open submarine channels and lobes in the vicinity of the channel-lobe transition zone of a submarine fan system. Different phases of sediment transport and deposition (lateral-accretion and aggradation stages) are identified in the channel infilling. Dual fan systems likely co-existed, one dominating and predominantly siliciclastic in nature (Moki Formation), and the other infrequent and involving the temperate calcareous deposits of Mangarara Formation. The Mangarara Formation is an outcrop analogue for middle Miocene-age carbonate slope-fan deposits elsewhere in subsurface Taranaki Basin, New Zealand