Mode mixing in asymmetric double trench photonic crystal waveguides

e investigate both experimentally and theoretically the waveguiding properties of a novel double trench waveguide where a conventional single-mode strip waveguide is embedded in a two dimensional photonic crystal (PhC) slab formed in silicon on insulator (SOI) wafers. We demonstrate that the bandwidth for relatively low-loss (50dB/cm) waveguiding is significantly expanded to 250nm covering almost all the photonic band gap owing to nearly linear dispersion of the TE-like waveguiding mode. The flat transmission spectrum however is interrupted by numerous narrow stop bands. We found that these stop bands can be attributed to anti-crossing between TE-like (positive parity) and TM-like (negative parity) modes. This effect is a direct result of the strong asymmetry of the waveguides that have an upper cladding of air and lower cladding of oxide. To our knowledge this is the first demonstration of the effects of cladding asymmetry on the transmission characteristics of the PhC slab waveguides.Comment: 7 pages, 6 figure

Data Recovery from SCATHA Satellite

This document gives a brief description of the SCATHA (P78-2) satellite and consolidates into one location information relevant to the generation of the SCATHA Summary Data parameters for the European Space Agency (ESA), under ESTEC Contract No. 11006/94/NL/CC, and the National Aeronautics and Space Administration (NASA), under Grant No. NAGW-414 1. Included are descriptions of the instruments from which the Summary Data parameters are generated, their derivation, and archival. Any questions pertaining to the Summary Data parameters should be directed to Dr. Joseph Fennell

Managing Dynamic User Communities in a Grid of Autonomous Resources

One of the fundamental concepts in Grid computing is the creation of Virtual Organizations (VO's): a set of resource consumers and providers that join forces to solve a common problem. Typical examples of Virtual Organizations include collaborations formed around the Large Hadron Collider (LHC) experiments. To date, Grid computing has been applied on a relatively small scale, linking dozens of users to a dozen resources, and management of these VO's was a largely manual operation. With the advance of large collaboration, linking more than 10000 users with a 1000 sites in 150 counties, a comprehensive, automated management system is required. It should be simple enough not to deter users, while at the same time ensuring local site autonomy. The VO Management Service (VOMS), developed by the EU DataGrid and DataTAG projects[1, 2], is a secured system for managing authorization for users and resources in virtual organizations. It extends the existing Grid Security Infrastructure[3] architecture with embedded VO affiliation assertions that can be independently verified by all VO members and resource providers. Within the EU DataGrid project, Grid services for job submission, file- and database access are being equipped with fine- grained authorization systems that take VO membership into account. These also give resource owners the ability to ensure site security and enforce local access policies. This paper will describe the EU DataGrid security architecture, the VO membership service and the local site enforcement mechanisms Local Centre Authorization Service (LCAS), Local Credential Mapping Service(LCMAPS) and the Java Trust and Authorization Manager.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 7 pages, LaTeX, 5 eps figures. PSN TUBT00

The Allometry of Daily Energy Expenditure in Hummingbirds: An Energy Budget Approach

1. Within-clade allometric relationships represent standard laws of scaling between energy and size, and their outliers provide new avenues for physiological and ecological research. According to the metabolic-level boundaries hypothesis, metabolic rates as a function of mass are expected to scale closer to 0.67 when driven by surface-related processes (e.g. heat or water flux), while volume-related processes (e.g. activity) generate slopes closer to one. 2. In birds, daily energy expenditure (DEE) scales with body mass (M) in the relationship log (DEE)=2.35+0.68×log (M), consistent with surface-level processes driving the relationship. However, taxon-specific patterns differ from the scaling slope of all birds. 3. Hummingbirds have the highest mass-specific metabolic rates among all vertebrates. Previous studies on a few hummingbird species, without accounting for the phylogeny, estimated that the DEE–body mass relationship for hummingbirds was log (DEE)=1.72+1.21×log (M). In Contrast to the theoretical expectations, this slope \u3e1 indicates that larger hummingbirds are less metabolically efficient than smaller hummingbirds. 4. We collected DEE and mass data for 12 hummingbird species, which, combined with published data, represented 17 hummingbird species in eight of nine hummingbird clades over a sixfold size range of body size (2.7–17.5 g). 5. After accounting for phylogenetic relatedness, we found DEE scales with body mass as log(DEE)=2.04+0.95×log (M). This slope of 0.95 is lower than previously estimated for hummingbirds, but much higher than the slope for all birds (0.68). The high slopes of torpor, hovering and flight potentially explain the high interspecific DEE slope for hummingbirds compared to other endotherms

Reply to “Geochemical Characteristics of Anatolian Basalts: Comment on ‘Neogene Uplift and Magmatism of Anatolia: Insights from Drainage Analysis and Basaltic Geochemistry’ by McNab et al.”

Uslular and Gençalioglu-Kuscu [2018] have written a lengthy, and highly critical, comment about McNab et al. [2018] which states that our data compilation for Neogene (and Quaternary) volcanic rocks from Anatolia is selective, inconsistent, and not fit for purpose. We state for the record that our compilation is not based on analyses from the published GEOROC database. Uslular and Gençalioglu-Kuscu [2018] also state that our sub-division of this database into three broad longitudinal categories is unrealistic since it does not consider the full range of different tectonic units. They conclude that our interpretation of the link between Neogene-Quaternary volcanism and uplift of Anatolia is erroneous. We refute this rather strongly worded comment by carefully addressing the five substantive issues raised

Reply to “Geochemical Characteristics of Anatolian Basalts: Comment on ‘Neogene Uplift and Magmatism of Anatolia: Insights from Drainage Analysis and Basaltic Geochemistry’ by McNab et al.”

Uslular and Gençalioğlu‐Kuşcu (2018) have written a lengthy, and highly critical, comment about McNab et al. (2018, https://doi.org/10.1002/2017GC007251) which states that our data compilation for Neogene (and Quaternary) volcanic rocks from Anatolia is selective, inconsistent, and not fit for purpose. We state for the record that our compilation is not based on analyses from the published GEOROC database. Uslular and Gençalioğlu‐Kuşcu (2018) also state that our subdivision of this database into three broad longitudinal categories is unrealistic since it does not consider the full range of different tectonic units. They conclude that our interpretation of the link between Neogene‐Quaternary volcanism and uplift of Anatolia is erroneous. We refute this rather strongly worded comment by carefully addressing the five substantive issues raised

Comparative physiology of Australian quolls (Dasyurus; Marsupialia)

Quolls (Dasyurus) are medium-sized carnivorous dasyurid marsupials. Tiger (3,840 g) and eastern quolls (780 g) are mesic zone species, northern quolls (516 g) are tropical zone, and chuditch (1,385 g) were once widespread through the Australian arid zone. We found that standard physiological variables of these quolls are consistent with allometric expectations for marsupials. Nevertheless, inter-specific patterns amongst the quolls are consistent with their different environments. The lower T ^sub b^ of northern quolls (34°C) may provide scope for adaptive hyperthermia in the tropics, and they use torpor for energy/water conservation, whereas the larger mesic species (eastern and tiger quolls) do not appear to. Thermolability varied from little in eastern (0.035°C °C^sup -1^) and tiger quolls (0.051°C ºC^sup -1^) to substantial in northern quolls (0.100°C ºC^sup -1^) and chuditch (0.146°C ºC^sup -1^), reflecting body mass and environment. Basal metabolic rate was higher for eastern quolls (0.662 ± 0.033 ml O^sub 2^ g^sup -1^ h^sup -1^), presumably reflecting their naturally cool environment. Respiratory ventilation closely matched metabolic demand, except at high ambient temperatures where quolls hyperventilated to facilitate evaporative heat loss; tiger and eastern quolls also salivated. A higher evaporative water loss for eastern quolls (1.43 ± 0.212 mg H^sub 2^O g^sup -1^ h^sup -1^) presumably reflects their more mesic distribution. The point of relative water economy was low for tiger (-1.3°C), eastern (-12.5°C) and northern (+3.3) quolls, and highest for the chuditch (+22.6°C). We suggest that these differences in water economy reflect lower expired air temperatures and hence lower respiratory evaporative water loss for the arid-zone chuditch relative to tropical and mesic quolls

Convergence of dynamic vegetation net productivity responses to precipitation variability from 10 years of MODIS EVI

According to Global Climate Models (GCMs) the occurrence of extreme events of precipitation will be more frequent in the future. Therefore, important challenges arise regarding climate variability, which are mainly related to the understanding of ecosystem responses to changes in precipitation patterns. Previous studies have found that Above-ground Net Primary Productivity (ANPP) was positively related to increases in annual precipitation and this relation may converge across biomes during dry years. One challenge in studying this ecosystem response at the continental scale is the lack of ANPP field measurements over extended areas. In this study, the MODIS EVI was utilized as a surrogate for ANPP and combined with precipitation datasets from twelve different experimental sites across the United States over a 10-year period. Results from this analysis confirmed that integrated-EVI for different biomes converged toward common precipitation use efficiency during water-limited periods and may be a viable surrogate for ANPP measurements for further ecological research