Reasoning with direction and rate of change in vegetation state transition modelling

Better integration in land planning and management can be supported through the use of suitable model-based tools. Vegetation state transition models have been noted as being useful in this context, providing a simple, useful means of capturing available ecological knowledge. We describe a simple ‘proof of concept’ rule-based system developed to contribute methodologically to management-oriented modelling of vegetated landscapes. The system is based upon a clear separation of direction from rate of change and the use of a general temporal reasoning system, a feature that facilitates modelling of situations where environmental change occurs causing an increase or decrease in rate without affecting direction of vegetation change. To ease model development and use the system represents vegetation dynamics in a way that has a close correspondence to the structure of understanding communicated by vegetation ecologists. A test model is described and run under different conditions to demonstrate the system. The results show that although the rule-based system and in particular the temporal reasoning system used operate successfully, there are a number of deficiencies in the modelling system as currently implemented. Future development possibilities are detailed along with a broader discussion regarding the needs of management-oriented modelling and the utility of state transition approaches.     

Large differences in substitutional pattern and evolutionary rate of 12S ribosomal RNA genes

We demonstrate using Drosophila, periodical cicadas, and hominid primates, that the molecular clock based on animal mitochondrial small-subunit (12S) rRNA genes ticks at significantly different relative rates depending on which taxa and which region of the gene are examined. Drosophila, which are commonly used as model taxa, are evolving in a highly peculiar manner with the majority of sites in the 3' half of the 12S gene apparently invariant. The analogous 3' half of the mitochondrial large-subunit rRNA gene (16S) appears to be similarly constrained. It is surprising that these regions that are already highly constrained in all animals should be even more constrained in Drosophila, especially when the Drosophila mitochondrial genome as a whole does not display a similar rate slowdown. This extreme 12S rate slowdown is not apparent in periodical cicadas or hominid primates and appears to be related to strong structural and functional constraints rather than a depressed mutation rate. Finally, the slow average rate of evolution in the third domain of Drosophila does not imply that the few variable sites lack multiple hits.     

Millimeter-wave radars for remotely sensing clouds andprecipitation

Millimeter-wave radars have been used since the early 1950s to study clouds and precipitation, but until recently these early instruments were limited to simple backscatter power measurements and were plagued by hardware problems. However, development of solid-state millimeter-wave componentry and high-power klystron amplifiers has spurred the evolution of reliable, coherent radars operating up to 95 GHz. In addition, advances in digital signal processing technology have resulted in single-card processors that can simultaneously execute algorithms to compute reflectivity, Doppler, and polarimetric quantities in real time. A review of the current state of the art in millimeter-wave cloud radars is presented, including a discussion of transmitters, antennas, and receiver components. Two radar systems built by the University of Massachusetts are described, including a mobile, dual-frequency (33- and 95-GHz) polarimetric radar, and an airborne 95-GHz polarimetric radar that was recently flown in a cooperative experiment with the University of Wyoming. Spaceborne applications are also discussed, especially the use of satellite-based 95-GHz radars for measuring the vertical distribution of clouds     

What is core? Guidelines for the core curriculum in paediatrics

This multicentre, randomised, double-blind, double-dummy, parallel group study was investigated in order to compare on 3 days the efficacy and the safety of the 16 mg once a day (od) ondansetron suppository (suppository group) with the recommended ondansetron treatment, i.e. 8 mg intravenous (i.v.) ondansetron on day 1 followed by 8 mg tablet (p.o.) twice daily (i.v. + p.o. group) on days 2 and 3 in patients receiving cisplatin (> or = 50 mg/m2) containing chemotherapy. In the 420 patients included in the intent-to-treat population, 209 received the 16 mg suppository and 211 the i.v. + p.o. treatment. The number of emetic episodes and the nausea score were recorded each day. Concerning the primary criterion, both treatments provided good anti-emetic control with 87% of all patients having a complete or major response (0-2 emetic episodes) on day 1 in the suppository group and 92% in the i.v. + p.o. group (P = 0.058). The 90% confidence interval for the difference between the two treatments for complete or major control was included in the interval (-15%, 15%) and showed that the treatment groups could be regarded as equivalent. Small differences in favour of the i.v. + p.o. group were observed concerning the secondary parameters. Both treatments were well tolerated. The results of this study show that both treatments are equivalent in the prevention of cisplatin-containing chemotherapy induced emesis for the primary efficacy criteria and that the ondansetron suppository is efficient and well tolerated and is a suitable alternative to the anti-emetic treatment combining the intravenous and oral routes.     

A computer model to assess fire hazards in tunnels (FASIT)

A computer model that simulates fire growth movement in tunnels is described, and a brief overview of tunnel systems is presented. The methods for predicting mass flows, velocities, smoke concentrations, and heat transfer are presented, along with a list of hazard output parameters. The validation of the model against experiment, and possible directions for future work are also presented.(previously with AEA Consultancy Services)     

Partial-SOI isolation structure for reduced bipolar transistorparasitics

A bipolar isolation structure with the capability of significantly reducing collector-base capacitance and base resistance is presented. Partial SOI, with SOI surrounding the collector opening, can be used to reduce the collector window width in combination with any emitter-base self-aligned bipolar device structure, and in particular for device structures that feature sublithographic emitter width. Near-ideal transistor Gummel characteristics and a minimum ECL gate delay of 24 ps have been achieved with a nonoptimized lateral device layout, and simulations suggest that sub-20-ps delay at reduced switch current will be possible by using the optimized partial-SOI isolation structure     

An airborne 95 GHz dual-polarized radar for cloud studies

A 95 GHz dual-polarization radar system was developed and flown on the University of Wyoming King Air research aircraft, from which it measured reflectivity, depolarization, and Doppler-derived velocity mean and standard deviation of a variety of clouds. This paper describes the radar and a data acquisition system that uses commercially available digitizers, signal processors, and signal generators. The authors also describe the tradeoffs between spatial resolution and ability to estimate reflectivity and velocity. This paper presents the first known airborne measurements of clouds made at 95 GHz; these are thought to be the most highly resolved millimeter-wave cloud images made to date. Depolarization, measured in terms of the linear depolarization ratio (LDR), was especially high in the melting band and in regions containing pristine ice crystals. These measurements demonstrate the advantages that high-spatial-resolution airborne millimeter-wave radars offer for the study of cloud microphysical properties     

Membranes,minerals, and proteins of developing vertebrate enamel

Developing tooth enamel is formed as organized mineral in a specialized protein matrix. In order to analyze patterns of enamel mineralization and enamel protein expression in species representative of the main extant vertebrate lineages, we investigated developing teeth in a chondrichthyan, the horn shark, a teleost, the guppy, a urodele amphibian, the Mexican axolotl, an anuran amphibian, the leopard frog, two lepidosauria, a gecko and an iguana, and two mammals, a marsupial, the South American short-tailed gray opossum, and the house mouse. Electron microscopic analysis documented the presence of a distinct basal lamina in all species investigated. Subsequent stages of enamel biomineralization featured highly organized long and parallel enamel crystals in mammals, lepidosaurians, the frog, and the shark, while amorphous mineral deposits and/or randomly oriented crystals were observed in the guppy and the axolotl. In situ hybridization using a full-length mouse probe for amelogenin mRNA resulted in amelogenin specific signals in mouse, opossum, gecko, frog, axolotl, and shark. Using immunohistochemistry, amelogenin and tuftelin enamel proteins were detected in the enamel organ of many species investigated, but tuftelin epitopes were also found in other tissues. The anti-M179 antibody, however, did not react with the guppy and axolotl enameloid matrix. We conclude that basic features of vertebrate enamel/enameloid formation such as the presence of enamel proteins or the mineral deposition along the dentin-enamel junction were highly conserved in vertebrates. There were also differences in terms of enamel protein distribution and mineral organization between the vertebrates lineages. Our findings indicated a correlation between the presence of amelogenins and the presence of long and parallel hydroxyapatite crystals in tetrapods and shark.     

Identifying and understanding header file hotspots in C/C++ build processes

Software developers rely on a fast build system to incrementally compile their source code changes and produce modified deliverables for testing and deployment. Header files, which tend to trigger slow rebuild processes, are most problematic if they also change frequently during the development process, and hence, need to be rebuilt often. In this paper, we propose an approach that analyzes the build dependency graph (i.e., the data structure used to determine the minimal list of commands that must be executed when a source code file is modified), and the change history of a software system to pinpoint header file hotspots—header files that change frequently and trigger long rebuild processes. Through a case study on the GLib, PostgreSQL, Qt, and Ruby systems, we show that our approach identifies header file hotspots that, if improved, will provide greater improvement to the total future build cost of a system than just focusing on the files that trigger the slowest rebuild processes, change the most frequently, or are used the most throughout the codebase. Furthermore, regression models built using architectural and code properties of source files can explain 32–57 % of these hotspots, identifying subsystems that are particularly hotspot-prone and would benefit the most from architectural refinement.