bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of anthropogenic food on the spatial behaviour of small Indian mongooses (Herpestes javanicus) in a subtropical rainforest
Authors: Quinn Jessica H. , Whisson Desley A.
Published: November 2005

The aim of this study was to determine the extent to which mongooses Herpestes javanicus in the Caribbean National Forest use areas of high human use, and to compare space use patterns in these areas to those in areas of low human use. It was expected that the abundance of anthropogenic food in areas of high human use would lead to (1) higher population densities; (2) smaller home ranges; (3) more extensive range overlap and reduced territorial behaviour, than areas of low use. During the dry season, 14 mongooses were radio‐collared and tracked in each of two areas: an area of high human use and an area of low human use. Six of these mongooses, one in an area of low human use and five in an area of high human use, were also tracked during the wet season. In both seasons, mongooses in the area of high human use used picnic areas more than expected based on availability. In the dry season, mongooses in the area of high human use had smaller home ranges than those in the area of low human use. Ranges overlapped extensively in both areas, and slightly more so in the area of low human use. However, individuals avoided each other spatially within the shared area of their ranges, and core home ranges overlapped little. In the wet (breeding) season, home‐range size and overlap increased more for males than for females. Such differences in behaviour and population dynamics in these two areas have implications for rabies transmission rates and management throughout the forest.
A comparative study of environmental factors that affect nesting in Australian and North American freshwater turtles
Authors: Bowen Kenneth D. , Spencer Ricky‐John , Janzen Fredric J.
Published: November 2005

The timing of reproductive events is critical for fitness, and these events are often linked to weather and climate. Weather components are thought to influence the nesting behaviour of freshwater turtles, but to date there have been few quantitative studies and no comparative studies. We compared the environmental cues used by nesting Australian (Emydura macquariiandChelodina expansa) and North American (Chrysemys picta) freshwater turtles, and quantified the differences in weather between days with and without nesting activity within the nesting season. We also characterized the diel time of nesting for each species. The results suggest that nesting behaviour is related to warm air and water temperatures inC. pictaand to rainfall inE. macquariiandC. expansa.Chrysemys pictaprimarily nests in the afternoon and evening,E. macquariiis a crepuscular nester, andC. expansanests diurnally. While changes in life history resulting from climate change are difficult to predict, we suggest that an increase in the number of El Niño events may have adverse effects on the two Australian species, whereas increases in environmental temperature may expand the number of nesting opportunities forC. picta.
Natal dispersal of Eurasian lynx (Lynx lynx) in Switzerland
Authors: Zimmermann Fridolin , Breitenmoser‐Würsten Christine , Breitenmoser Urs
Published: November 2005

Dispersal influences the dynamics and persistence of populations, the distribution and abundance of species, and gives the communities and ecosystems their characteristic texture in space and time. The Eurasian lynx Lynx lynx is a medium‐sized solitary carnivore that has been re‐introduced in central Europe and currently occurs in rather small populations, where dispersal is believed to play a prominent role for the recolonization of unsettled areas and persistence of subpopulations. Between 1988 and 2001 the spatio‐temporal behaviour of sub‐adult Eurasian lynx was studied in two re‐introduced populations in Switzerland, based on 31 juveniles of which 24 were radio‐tagged to find out which factors influence dispersal. Age at independence ranged from 8.1 to 10.7 months and did not differ between populations or sex. Independence began from January to the beginning of May with a peak in April. After independence, sub‐adults stayed a few days in the maternal home range. Age at dispersal differed between the areas of origin and was possibly affected by sex and the presence of new progeny. Dispersers of both sexes established transient home ranges; however, only one male in the saturated population established a transient home range. Although only females took over the maternal home range, there was no significant sex bias in the proportion of individuals that dispersed in both populations. Successful dispersers settled in a territory at distances that differed between populations with effects of sex, but not condition. The mean dispersal distance in the high‐density population was 25.9 km compared to 63.1 km in the low‐density population. Dispersal distances in the high‐density population – shorter than those reported in other Eurasian lynx studies but comparable to those observed in an Iberian lynx population – are limited by habitat restrictions hindering connections with a neighbouring population.
‘Island syndrome’ in a population of Arctic foxes (Alopex lagopus) from Mednyi Island
Authors: Goltsman Mikhail , Kruchenkova Elena P. , Sergeev Sergei , Volodin Ilja , Macdonald David W.
Published: November 2005

Comparative analysis of the biology of insular and mainland populations has demonstrated a number of differences in characteristics of insular populations, termed the ‘island syndrome’. A subspecies of Arctic fox on the Commander Islands (Alopex lagopus semenovion Mednyi Island) has been isolated for an evolutionarily significant time in small territories at the periphery of the species' range. The number of foxes on Mednyi had been observed to be very high since the islands were discovered in 1741, but a drastic decline in population density in the late 1970s, owing to mange, has left the population low. The aim of the study was to determine whether the Mednyi Arctic fox population exhibited the features expected in an isolated insular population, such as difference in body size, increased population density, larger social groups, lower tendency to disperse and lower fertility, and whether any behavioural changes were evolutionarily reinforced or were a temporal response to current ecological factors on the island. Eight predictions were identified based on the island syndrome, of which the Mednyi Arctic foxes conformed to seven. We suggest a new prediction, namely that the tendency for increased sex dimorphism in dispersal may also be a distinguishing feature of insular populations. All the features displayed by the insular population on Mednyi – conservative use of space, increased tendency to form complex groups, decreased fertility and dispersal – seemed to be preserved regardless of the currently comparatively low populations. Thus, although foxes have been below carrying capacity for at least 10 generations, island syndrome characteristics have persisted.
Kinematic analysis of swimming in Australian box jellyfish, Chiropsalmus sp. and Chironex fleckeri (Cubozoa, Cnidaria: Chirodropidae)
Authors: Shorten Marc , Davenport John , Seymour James E. , Cross Mary C. , Carrette Teresa J. , Woodward Guy , Cross Thomas F.
Published: November 2005

Locomotion of the box jellyfish Chiropsalmus sp. (cf quadrigatus)1 (Haeckel) and Chironex fleckeri (Southcott) was analysed using digital video. Specimens of Chiropsalmus sp. and C. fleckeri were collected in 2001 and 2002, respectively, from coastal waters of Northern Queensland, Australia. Chiropsalmus sp. animals were videoed swimming in an aquarium, and C. fleckeri in a large outdoor tank. Locomotor sequences of nine Chiropsalmus sp. and seven C. fleckeri individuals were analysed using video techniques. A subset of animals had fluorescent dye injected into the sub‐umbrellar cavity, to allow observation of water movements during ejection from the bell. Both species used an intermittent style of jet propulsion similar to that documented for some other species of cubozoan medusae. Computer analysis allowed examination of positions of bell parts over time intervals (0.04 s) by comparing coordinates of nodes marked on various bell parts using imaging software. Examination of node coordinates allowed a detailed qualitative description of gait, in addition to quantitative statistical analyses. General linear modelling showed that interspecific differences in locomotion were explicable in terms of body size. Larger animals of both species tended to swim faster, and with a lower pulse frequency, than smaller individuals. Smaller animals also tended to swim faster relative to their bell diameter.
Does prey size induce head skeleton phenotypic plasticity during early ontogeny in the snake Boa constrictor?
Authors: Schuett Gordon W. , Hardy David L. , Earley Ryan L. , Greene Harry W.
Published: November 2005

Diet was manipulated in juveniles of the snake Boa constrictor (Serpentes: Boidae) to test the hypothesis of whether prey size induces phenotypic plasticity of the head skeleton. Additionally, the onset of sexual size dimorphisms (SSDs) was determined under a feeding schedule where total prey mass consumed by snakes was held constant. Twenty‐three neonatal B. constrictor from a single‐sired litter were placed into two treatment groups but maintained under identical environmental conditions. Group 1 (small‐food treatment) was fed weanling mice throughout the entire study; group 2 (large‐food treatment) was fed weanling mice, followed by rats of increasing size as the size of the snakes increased. At the termination of the study, group 1 consumed more meals but both groups consumed an equivalent mass of rodents. The snakes were measured twice during the study (5 weeks and 58 weeks). All measurements were obtained while the snakes were under general anaesthesia. Linear measurements of the head skeleton (premaxilla–basioccipital (rostrum–occipital) length, ROL; mandible length, ML) were derived from radiographs. The remaining measurements were snout–vent length (SVL), body length (BL), tail length (TL), and body mass (BM). Treatment effects between groups were equivalent, with the exception of BM and TL (group 1>group 2), and interactions between main effects were not statistically significant. Between‐group differences in ROL and ML were not significant; thus, prey size did not exert an influence on growth of the head skeleton. In contrast, significant sex effects on SVL and BL (females>males) and TL (males>females) were detected, and sex effects on BM (females>males) approached significance. Because SSDs emerged during early ontogeny under conditions where prey mass consumed was held constant, a genetic role is implicated.
Synchrony and timing of breeding influences sexual segregation in western grey and red kangaroos (Macropus fuliginosus and M. rufus)
Authors: MacFarlane Abigail M. , Coulson Graeme
Published: November 2005

We examined whether synchrony and timing of breeding influenced magnitude and timing of sexual segregation in sympatric western grey kangaroos Macropus fuliginosus and red kangaroos M. rufus, at Hattah‐Kulkyne National Park, in south‐eastern Australia. These species vary in the synchrony and timing of their mating activity: western grey kangaroos mate during a relatively synchronous period, predominantly during spring, while red kangaroos mate throughout the year. Surveys were conducted during autumn and spring 2000 to examine seasonal patterns of mating activity, group composition, spatial distribution, and habitat selection of adults of both species. Habitat selection was also examined by analysing data from culls conducted from 1998 to 2002. Mating activity occurred synchronously in western grey kangaroos, thus, like in many ungulate species, there was a time of peak segregation, during autumn, when females were in lactational anoestrus, and a time of peak aggregation, during the period of peak mating activity in spring. In red kangaroos, mating activity occurred during both seasons, but showed a slight peak during autumn. Consequently, segregation was weaker than in western grey kangaroos but occurred through‐out the year, with a slight peak during spring. The degree of social and spatial segregation in western grey and red kangaroos was comparable to that in ungulates, while habitat segregation was considerably lower than is typically seen in ungulates. These results indicate that breeding phenology is a major factor involved in sexual segregation, and highlight the importance of directing attention at the general conditions underlying this phenomenon.
Network Dynamics in Sustainable: a robotic sound installation
Authors: BIRCHFIELD DAVID , LORIG DAVID , PHILLIPS KELLY
Published: November 2005

The network serves as a conceptual, metaphorical, practical and musical force that drives Sustainable, a dynamic robotic sound installation. The piece is comprised of seven autonomous water gong nodes that are networked together by water tubes to distribute water throughout the system. A water resource allocation algorithm guides this distribution process and produces an ever-evolving sonic and visual texture. A simple set of behaviours govern the individual gongs, and the system as a whole exhibits emergent properties that yield local and large-scale forms in sound and light that are visually and musically compelling.
Interactive Network Performance: a dream worth dreaming?
Authors: KAPUR AJAY , WANG GE , DAVIDSON PHILIP , COOK PERRY R.
Published: November 2005

This paper questions and examines the validity and future of interactive network performance. The history of research in the area is described as well as experiments with our own system. Our custom-built networked framework, known as GIGAPOPR, transfers high-quality audio, video and MIDI data over a network connection to enable live musical performances to occur in two or more distinct locations. One of our first sensor-augmented Indian instruments, The Electronic Dholak (EDholak) is a multi-player networked percussion controller that is modelled after the traditional Indian Dholak. The EDholaks trigger sound, including samples and physical models, and visualisation, using our custom-built networked visualisation software, known as veldt.
Local Performance Networks: musical interdependency through gestures and controllers
Authors: WEINBERG GIL
Published: November 2005

Informed by a proposed theoretical framework for the field of interconnected musical networks (Weinberg 2005), I describe a set of local musical networks that utilise novel gestural controllers for interdependent collaborative performance. The paper begins by contextualising developments in the field of musical networks in correlation with development of technological innovations, leading to the utilisations of gestural controllers in local musical networks. This introduction leads to the definition and categorisation of theoretical and practical approaches for the design of local gestural networks, addressing motivations, social strategies, network architectures, musical content, and control software and hardware. Based on this theoretical framework I describe the evolution of four local musical networks that utilise newly developed gestural controllers, titled ‘Squeezables’, ‘Musical Fireflies’, ‘Beatbugs’ and ‘Voice Patterns’. The paper discusses the design and development process of these projects and ends with a comparative analysis of the networks and controllers based on conceptual and practical criteria.
Berufsgruppenübergreifende Kooperation in der medizinischen Rehabilitation
Authors: Körner Mirjam , Schüpbach Heinz , Bengel Jürgen
Published: November 2005

Zusammenfassung. Die berufsgruppenübergreifende Kooperation gilt als ein bedeutendes Qualitätsmerkmal in der medizinischen Rehabilitation. Zur Charakterisierung der Zusammenarbeit im Rehabilitationsteam sind verschiedene Teammodelle denkbar. Am häufigsten werden das multi- und interdisziplinäre Teammodell differenziert. Diese beiden Teamformen unterscheiden sich bezüglich der Kriterien “Organisation und Management“ und “Kommunikationsstruktur“. Für Teamanalysen sollten neben dem Teammodell der Teamprozess und der Teamerfolg sowie deren Zusammenhänge erfasst werden. Derzeit fehlen sowohl konzeptuelle als auch methodische Grundlagen für die Durchführung von systematischen Teamanalysen. Die Konzeption eines heuristischen Modells zur Erfassung und Bewertung der berufsgruppenübergreifenden Kooperation in Teams der medizinischen Rehabilitation und damit die Schaffung einer Basis für die Implementierung und Evaluation von Teamentwicklungsmaßnahmen wird vorgestellt.
Das Gletscherbahnunglück von Kaprun in Österreich im Jahr 2000
Authors: Brauchle Gernot
Published: November 2005

Zusammenfassung. Es werden die Zusammenhänge zwischen Posttraumatischen Belastungsstörungen, Copingstrategien sowie intrusiven Erinnerungen bei Kriminalbeamten nach dem Gletscherbahnunglück von Kaprun, Österreich (2000) untersucht. In einer prospektiven Längsschnittuntersuchung wurden über zwei Zeitpunkte hinweg, sechs Wochen (t1) und sechs Monate (t2), 74 Kriminalbeamte mit Hilfe der “Posttraumatic Stress Diagnostic Scale“ (PDS), dem “Coping Strategies Questionnaire“ sowie dem “Response to Intrusion Questionnaire“ (RIQ, Clohessy & Ehlers, 1999 ) untersucht. Sechs Wochen bzw. sechs Monate nach dem Ereignis war bei sechs Kriminalbeamten (9.4%) eine Posttraumatische Belastungsstörung feststellbar. Wunschdenken, Vermeidung, emotionale Katharsis und Positive Re-Interpretation korrelierten mit Symptomen der Posttraumatischen Belastungsstörung zum Messzeitpunkt t2. Negative Einschätzungen intrusiver Erinnerungen und Dissoziation erklärten 35% (t1) bzw. 22% (t2) der Varianz Posttraumatischer Belastungsstörungen. Psychologische Faktoren wie Negative Interpretationen intrusiver Erinnerungen und Dissoziation tragen wesentlich zur Entwicklung und Aufrechterhaltung posttraumatischer Belastungssymptome bei.
Variations in the rotation rate of Venus due to orbital eccentricity modulation of solar tidal torques
Authors: Bills Bruce G.
Published: November 2005

The rotational state of Venus is presumably determined by a balance between two different solar tidal torques: an atmospheric thermal tide yields a torque which acts in the same direction as the retrograde rotation of Venus and a gravitational solid body tide yields a torque which opposes the current rotation. The strengths of these opposing torques both depend on the eccentricity of the orbit of Venus but with different sensitivities. Thus variations in the orbital eccentricity cause fluctuations in the rotation rate at which the tidal torques balance. If Venus is considered to be a single rigid body, the rotational velocity will change by amounts equivalent to ∼1 km/yr at the equator, over timescales of 106 years. Allowance for differential rotation between the core, mantle, and atmosphere increases the range over which the solid surface rotation rate varies. For plausible values of the strength of viscous coupling at the atmosphere‐mantle boundary and the core‐mantle boundary the variations in solid surface rotational velocity can be 2–3 times larger than in the rigid coupling case. When these long‐period forced variations in rotation rate are considered, the present rotation rate of Venus is seen to be close enough to a resonant spin‐orbit interaction with the Earth that it may occasionally pass through that resonance.
Extreme interplanetary rotational discontinuities at 1 AU
Authors: Lepping R. P. , Wu C.‐C.
Published: November 2005

This study is concerned with the identification and description of a special subset of four Wind interplanetary rotational discontinuities (from an earlier study of 134 directional discontinuities by Lepping et al. (2003)) with some “extreme” characteristics, in the sense that every case has (1) an almost planar current sheet surface, (2) a very large discontinuity angle (ω), (3) at least moderately strong normal field components (>0.8 nT), and (4) the overall set has a very broad range of transition layer thicknesses, with one being as thick as 50REand another at the other extreme being 1.6RE, most being much thicker than are usually studied. Each example has a well‐determined surface normal (n) according to minimum variance analysis and corroborated via time delay checking of the discontinuity with observations at IMP 8 by employing the local surface planarity. From the variance analyses, most of these cases had unusually large ratios of intermediate‐to‐minimum eigenvalues (λI/λmin), being on average 32 for three cases (with a fourth being much larger), indicating compact current sheet transition zones, another (the fifth) extreme property. For many years there has been a controversy as to the relative distribution of rotational (RDs) to tangential discontinuities (TDs) in the solar wind at 1 AU (and elsewhere, such as between the Sun and Earth), even to the point where some authors have suggested that RDs with large ∣Bn∣s are probably not generated or, if generated, are unstable and therefore very rare. Some of this disagreement apparently has been due to the different selection criteria used, e.g., some allowed eigenvalue ratios (λI/λmin) to be almost an order of magnitude lower than 32 in estimatingn, usually introducing unacceptable error innand therefore also in ∣Bn∣. However, we suggest that RDs may not be so rare at 1 AU, but good quality cases (where ∣Bn∣ confidently exceeds the error in ∣Bn∣) appear to be uncommon, and further, cases of large ∣Bn∣ may indeed be rare. Finally, the issue of estimating the number of RDs‐to‐TDs was revisited using the full 134 events of the original Lepping et al. (2003) study (which utilized the RDs' propagation speeds for this estimation, an unconventional approach) but now by considering only normal field components, the more conventional approach. This resulted in slightly different conclusions, depending on specific assumptions used, making the unconventional approach suspect.
A simple model of the auroral kilometric radiation visibility
Authors: Schreiber R.
Published: November 2005

Examples of data collected with Polrad swept frequency analyzer during almost 2.5 years of Interball‐2 mission are used to demonstrate directivity properties of the auroral kilometric radiation (AKR) observed in the Northern Hemisphere. In contrast to the previous, mostly statistical studies, single dynamic spectra have been analyzed. Simple modeling of AKR source visibility from the location of the observer reproduces the overall form of the dynamic spectrum with a single set of AKR source parameters valid during up to tens of minutes. Cases of filled and partially filled emission cones as well as smaller emission cones embedded in the main cone are found. Anisotropic AKR beams as thin as 10° and sometimes narrower are consistent with our model.
ICESat validation of SRTM C‐band digital elevation models
Authors: Carabajal Claudia C. , Harding David J.
Published: November 2005

The Geoscience Laser Altimeter System (GLAS) on the Ice, Cloud, and land Elevation Satellite (ICESat) provides a globally‐distributed data set well suited for evaluating the vertical accuracy of Shuttle Radar Topography Mission (SRTM) digital elevation models (DEMs). The horizontal error (2.4 ± 7.3 m) and vertical error (0.04 ± 0.13 m per degree of incidence angle) for the ICESat data used are small compared to those for SRTM. Using GLAS echo waveforms we document differences between the SRTM C‐band phase center and the highest, centroid, and lowest elevations within ICESat laser footprints in the western United States. In areas of low relief and sparse tree cover, the mean and standard deviation of elevation differences between the ICESat centroid and SRTM are −0.60 ± 3.46 m. The differences are −5.61 ± 15.68 m in high relief, sparse tree cover areas, and −3.53 ± 8.04 m in flat areas with dense tree cover. The largest differences occur in rugged, densely‐vegetated regions.
D region ionization by lightning‐induced electromagnetic pulses
Authors: Mende S. B. , Frey H. U. , Hsu R. R. , Su H. T. , Chen A. B. , Lee L. C. , Sentman D. D. , Takahashi Y. , Fukunishi H.
Published: November 2005

The electromagnetic pulses (EMP) from tropospheric lightning produce transient luminous events (TLEs), known as elves, in the 80–90 km region above the lightning. The luminosity is evidence that the EMP carries sufficient electric field to excite optical emissions at these altitudes; however, it is still unknown whether the field is sufficient to ionize the atmosphere. The first multiwavelength, quantitative observatory on a free‐flying satellite dedicated to observing TLEs, the Imager of Sprites and Upper Atmospheric Lightning (ISUAL) instrument on FORMOSAT‐2, formerly called ROCSAT‐2, confirmed that a significant number of lightning events are accompanied by elves. The instrument consists of a low light level imager and a set of multichannel photometers. In a few cases where the lightning occurred beyond the solid Earth limb, pure spectral measurements of the elves were obtained. Here we analyze such an event and show that the elves contained significant 391.4 nm emission of the N2+ ion. This is clear evidence that ionization takes place in elves. The ratio of cross sections for N2 ionization and the production of the upper state of 391.4 nm emission is not a constant for low‐energy electrons found in TLEs. We attempted to find this ratio by comparing our photometric measurements of the TLE produced emissions to theoretically derived emission intensities. The electron energy distribution and the ratios of the modeled N2 Lyman‐Birge‐Hopfield (LBH) and the N2+ first negative to the second positive were computed as a function of the reduced electric field. From these ratios it was possible to obtain the reduced electric field from the ratios. We estimated that the reduced electric field, which characterizes the local electron energy distribution, was >200 Td. We also made comparisons of the theoretically derived intensities to our measurements of the N2+ first positive and Lyman‐Birge‐Hopfield (LBH) band emission in the elves. On the basis of the ratio between the N2+ first negative emission and the time‐integrated ionization production, we estimate that the elves produced an average electron density of 210 electrons cm−3 over a large (165 km diameter) circular region having an assumed 10 km altitude extent. These observations indicate that thunderstorms are a significant source of ionization in the low‐ to midlatitude nighttime D region.
Auroral kilometric radiation activity during magnetically quiet periods
Authors: Morioka A. , Miyoshi Y. S. , Tsuchiya F. , Misawa H. , Kumamoto A. , Oya H. , Matsumoto H. , Hashimoto K. , Mukai T.
Published: November 2005

The behavior of auroral kilometric radiation (AKR) during magnetically quiet periods is investigated. A clear AKR onset sometimes occurs without any typical substorm signatures characterized by auroral electrojet enhancement on the ground, tail current disruption in the near‐Earth plasma sheet, and energetic particle injection from the plasma sheet. However, the onset is accompanied by auroral brightening on the contracted oval, Pi2 pulsation on the ground, and fast plasma flow in the plasma sheet. These features of quiet‐time AKR seem consistent with a contracted oval substorm, indicating that the onset of AKR is one of the elementary components of the contracted substorm. Unexpected features showing that AKR spectra do not always depend on the substorm magnitude are also presented: (1) the AKR intensity during the magnetically quiet period was sometimes comparable with the usual substorm AKR, and (2) the frequency‐bandwidth expansion of AKR at the time of onset, which is considered to be related with the vertical development of the field‐aligned potential during the substorm, was sometimes comparable between quiet‐ and disturbed‐period AKR.
Topographic control of hydrogen deposits at low latitudes to midlatitudes of Mars
Authors: Feldman W. C. , Prettyman T. H. , Maurice S. , Nelli S. , Elphic R. , Funsten H. O. , Gasnault O. , Lawrence D. J. , Murphy J. R. , Tokar R. L. , Vaniman D. T.
Published: November 2005

Correlations between the longitudinal wave number two distribution of water‐equivalent hydrogen (WEH) at low latitudes to midlatitudes of Mars with variations in topography, surface albedo, thermal inertia, regional dust storms, and atmospheric water vapor are explored to provide guidance in determining the mechanisms that recharge or maintain these WEH reservoirs. The closest match is with low thermal inertia coupled with orographic control of the present‐day atmospheric circulation dynamics. The engine for the simulated longitudinal two‐wave pattern (maxima in Arabia and Tharsis) is relatively cold nighttime surface temperatures and large‐amplitude temperature inversions that concentrate water ice over these regions. Geologically recent precipitated water ice, by itself, is insufficient to account for the observed distribution of WEH. Retention of precipitate by hydratable minerals is necessary. While current research cannot presently identify the hydration mechanism for the WEH distribution (whether it be from a past obliquity, present climate conditions, or some convolution of both), this research suggests that current climatic conditions can sustain, if not emplace, the observed longitudinally constrained distribution of equatorial WEH.
The Effect of SNP Marker Density on the Efficacy of Haplotype Tagging SNPs – a Warning
Authors: Iles Mark M.
Published: November 2005

We investigate here the efficacy of selecting haplotype tagging SNPs at different marker densities (2kb‐10kb). Our results are based on publicly available data on 5324 markers with a median spacing of 1kb from chromosome 20. We find that whatever density of SNPs is used, htSNP analysis indicates in most cases that at least 80% of the variation can be captured using a subset of SNPs. However, as marker density decreases these htSNPs become increasingly unreliable. In this dataset htSNPs were selected to capture at least 80% of the variation at every observed SNP. At an observed SNP density of 2kb, htSNP analysis suggests that the htSNPs capture on average 95% of the observed variation, when in fact they capture 88% of the unobserved variation. At a density of 10kb, htSNP analysis suggests that 93% of the observed variation was captured, when in fact they capture on average only 78%. Our results indicate that htSNP analysis is only reliable when markers are dense – a spacing of even 2kb shows a considerable loss of information. Such findings are important both for individual studies utilising htSNPs to reduce costs, and for projects such as HapMap which try to characterise human genomic variation using htSNPs.
The Y‐chromosomal Heritage of the Azores Islands Population
Authors: Pacheco P. R. , Branco C. C. , Cabral R. , Costa S. , Araújo A. L. , Peixoto B. R. , Mendonça P. , Mota‐Vieira L.
Published: November 2005

The Azores, a Portuguese archipelago located in the north Atlantic Ocean, had no native population when the Portuguese first arrived in the 15th century. The islands were populated mainly by the Portuguese, but Jews, Moorish prisoners, African slaves, Flemish, French and Spaniards also contributed to the initial settlement. To understand the paternal origins and diversity of the extant Azorean population, we typed genomic DNA samples from 172 individuals using a combination of 10 Y‐biallelic markers (YAP, SRY‐1532, SRY‐2627, 92R7, M9, sY81, Tat, SRY‐8299, 12f2 and LLY22g) and the following Y‐chromosomal STR systems: DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393 and DYS385. We identified nine different haplogroups, most of which are frequent in Europe. Haplogroup J* is the second most frequent in the Azores (13.4%), but it is modestly represented in mainland Portugal (6.8%). The other non‐European haplogroups, N3 and E3a, which are prevalent in Asia and sub‐Saharan Africa, respectively, have been found in the Azores (0.6% and 1.2%, respectively) but not in mainland Portugal. Microsatellite data indicate that the mean gene diversity (D) value for all the loci analysed in our sample set is 0.590, while haplotype diversity is 0.9994. Taken together, our analysis suggests that the current paternal pool of the Azorean population is, to a great extent, of Portuguese descent with significant contributions from people with other genetic backgrounds.
Spinal Muscular Atrophy Carrier Screening by Multiplex Polymerase Chain Reaction using Dried Blood Spot on Filter Paper
Authors: Majumdar R. , Rehana Z. , Jumah M. Al , Fetaini N.
Published: November 2005

Spinal muscular atrophy (SMA) is a common, often fetal, autosomal recessively inherited disease leading to progressive muscle wasting and paralysis as a result of degeneration of anterior horn cells of the spinal cord. The SMA‐determining gene, called the survival of motor neuron gene (SMN), is present on 5q13 in two nearly identical copies, telomeric SMN (SMN1) and centromeric SMN (SMN2). It has been established that SMA is caused by mutations in SMN1 whereas homozygous deletion of SMN2 has apparently no pathological consequences. The aim of this study is to develop an easy and inexpensive method for the isolation of high‐quality template DNA from blood samples for SMA carrier screening by multiplex polymerase chain reaction. We have developed a protocol that optimizes detection of the SMN1 copy number in the human genome, producing a specific and sensitive assay using DNA extracted from a dried blood spot on IsoCode™ paper.
A Method for Pooling Alleles from Different Genotyping Experiments
Authors: Aulchenko Y. S. , Bertoli‐Avella A. M. , Van Duijn C. M.
Published: November 2005

Single tandem repeat (STR) polymorphisms are widely used in linkage and association studies. One of the drawbacks of using these markers is that genetic data coming from different experiments cannot be easily pooled together, because both allele length and binning distance may change. As large studies with multiple series of subjects sequentially included become more and more common, there is an increasing interest in pooling the genetic data obtained in different experiments. Correct reconstruction of allelic correspondences between genotyping experiments is particularly crucial for association‐oriented studies, such as candidate gene studies and genome‐wide association studies in isolated populations.

Here, we suggest a maximum‐likelihood framework to find the best correspondence between alleles typed in different genotyping experiments. We also address the issue of goodness‐of‐fit and robustness. We perform a study simulating results obtained in a genome scan using 787 STR markers. The simulations show that the suggested method yields good results with respect to the error rate, even if the sizes of the samples to be pooled are as low as 10 subjects (3% errors), though only 9% of alleles pass our tests. As sample sizes increase to 250 subjects the proportion of alleles pooled reaches 96% with an error rate of <0.1%.
Generating Genetic Risk Scores from Intermediate Phenotypes for Use in Association Studies of Clinically Significant Endpoints
Authors: Horne B. D. , Anderson J. L. , Carlquist J. F. , Muhlestein J. B. , Renlund D. G. , Bair T. L. , Pearson R. R. , Camp N. J.
Published: November 2005

While previous results of genetic association studies for common, complex diseases (eg., coronary artery disease, CAD) have been disappointing, examination of multiple related genes within a physiologic pathway may provide improved resolution. This paper describes a method of calculating a genetic risk score (GRS) for a clinical endpoint by integrating data from many candidate genes and multiple intermediate phenotypes (IPs). First, the association of all single nucleotide polymorphisms (SNPs) to an IP is determined and regression β‐coefficients are used to calculate an IP‐specific GRS for each individual, repeating this analysis for every IP. Next, the IPs are assessed by a second regression as predictors of the clinical endpoint. Each IP's individual GRS is then weighted by the regression β‐coefficients from the second step, creating a single, composite GRS. As an example, 3,172 patients undergoing coronary angiography were evaluated for 3 SNPs from the cholesterol metabolism pathway. Although these data provide only a preliminary example, the GRS method detected significant differences in CAD by GRS group, whereas separate genotypes did not. These results illustrate the potential of the GRS methodology for multigenic risk evaluation and suggest that such approaches deserve further examination in common, complex diseases such as CAD.
Effective density terms in proper integral equations
Authors: Dyer Kippi M. , Perkyns John S. , Pettitt B. Montgomery
Published: November 2005

Two complementary routes to a new integral equation theory for site-site molecular fluids are presented. First, a simple approximation to a subset of the atomic site bridge functions in the diagrammatically proper integral equation theory is presented. This in turn leads to a form analogous to the reactive fluid theory, in which the normalization of the intramolecular distribution function and the value of the off-diagonal elements in the density matrix of the proper integral equations are the means of propagating the bridge function approximation. Second, a derivation from a topological expansion of a model for the single-site activity followed by a topological reduction and low-order truncation is given. This leads to an approximate numerical value for the new density coefficient. The resulting equations give a substantial improvement over the standard construction as shown with a series of simple diatomic model calculations.
M
4
@
Si
28
(M=Al,Ga): Metal-encapsulated tetrahedral silicon fullerene
Authors: Gao Yi , Zeng X. C.
Published: November 2005

It is known that silicon fullerenes cannot maintain perfect cage structures like carbon fullerenes. Previous density-functional theory calculations have shown that even with encapsulated species, nearly all endohedral silicon fullerenes exhibit highly puckered cage structures in comparison with their carbon counterparts. In this work, we present theoretical evidences that the tetrahedral fullerene cage Si28 can be fully stabilized by encapsulating a tetrahedral metallic cluster (Al4 or Ga4). To our knowledge, this is the first predicted endohedral silicon fullerene that can retain perfectly the same cage structure (without puckering) as the carbon fullerene counterpart (Td-C28 fullerene). Density-functional theory calculations also suggest that the two endohedral metallosilicon fullerenes Td-M4@Si28 (M=Al and Ga) can be chemically stable because both clusters have a large highest occupied molecular orbital-lowest unoccupied molecular orbital energy gap (∼0.9eV), strong spherical aromaticity (nucleus-independent chemical shift value of −36 and −44), and large binding and embedding energies.
Cooperative versus dispersion effects: What is more important in an associated liquid such as water?
Authors: Kirchner Barbara
Published: November 2005

We implemented the quantum cluster equilibrium theory in our postprocessing program PEACEMAKER. This program may be run in conjunction with the very efficient vibrational frequency analysis code SNF and can therefore provide access to all electronic structure programs combined with this program. We applied the quantum cluster equilibrium theory in order to investigate the influence of a wide range of electronic structure models on the description of the liquid state. This investigation revealed much about the relevance of approximations in modern simulations of associated liquids such as water. While it is often claimed that the use of density-functional theory in condensed matter is leading to gravely erroneous results, we found that, contrary to these assertions, the exact exchange functional B3LYP and the gradient-corrected functional BP perform very well in combination with sizable basis sets as compared to second-order Møller-Plesset perturbation theory employing the same basis set. The use of density-functional theory with smaller basis sets does, in fact, lead to better results in the liquid state than the use of second-order Møller-Plesset perturbation theory in combination with these small basis sets. Most importantly, the neglect of cooperative effects disturbs a good description much more evenly if we apply second-order Møller-Plesset perturbation theory in combination with large basis sets than density-functional theory including cooperativity with smaller basis sets or Hartree-Fock using a very small basis set.
Laser gain properties of AlGaN quantum wells
Authors: Chow W. W. , Kneissl M.
Published: November 2005

Laser gain is investigated for AlGaN wurtzite quantum-well structures emitting in the wavelength range from ∼270to340nm. The calculations show that gain properties vary notably with aluminum concentration in the quantum well. The TE gain dominates over the entire spectral range, although an enhancement of TM gain is observed for AlGaN quantum wells with the high aluminum mole fraction. The calculations also predict an increase in threshold current density for the shorter-wavelength lasers.
Improved vibroacoustography imaging for nondestructive inspection of materials
Authors: Mitri F. G. , Fatemi M.
Published: November 2005

We report a method to improve image quality in the nondestructive investigation and visualization of defects using vibroacoustography (VA). Vibroacoustography is an ultrasound-based imaging technique that uses the dynamic (oscillatory) radiation force of low-frequency excitation (within kilohertz range) to remotely vibrate objects and detect the ensuing acoustic emission. This technique is nondestructive and noncontact and has shown numerous capabilities to produce high-resolution images of different types of materials. However, for reflective materials, ultrasound reflects back and forth between the object and transducer, thus establishing standing waves. This phenomenon produces an artifact in the shape of false contours in the VA images. The goal of this study is to investigate the formation of the standing wave artifacts and develop a process called chirp imaging to improve defect visibility and flaw detection capability. Chirp VA experiments are performed on a flawed fiber-reinforced ceramic composite plate and on an electronic chip. To assess the efficacy of the chirp imaging process in removing the standing-wave artifact, the resulting chirp images are compared to “fixed frequency” VA images. Results show that the false contour can be significantly reduced in the image, thus remarkably improving image quality and flaw detection.
Independent measurement of air-bearing pitch, roll, and vertical modulation
Authors: Kiely James D. , Hsia Yiao-Tee
Published: November 2005

We describe a method of measuring the dynamic changes in pitch and roll angle of air-bearing sliders used in hard disk drive magnetic recording. The technique provides simultaneous, single-point measurements of the dynamic changes in pitch angle, roll angle, and vertical position. We apply the technique to characterize the dynamic responses of a slider reacting to an idealized disk defect and demonstrate how different translation and rotational modes get excited sequentially. Spectrogram analysis is then applied to illustrate the changes in frequency content of the three different modulation modes. We model the slider response as an impulse response to provide experimental determination of response frequencies and damping factors. We perform these analyses as a function of rotational velocity and find that response frequencies increase and damping factors decrease with decreasing velocity. These analyses provide insight into factors controlling slider dynamics and demonstrate the utility of the technique.
Simulating the thermal behavior and fragmentation mechanisms of exohedral and substitutional silicon-doped C60
Authors: Marcos P. A. , Alonso J. A. , López M. J.
Published: November 2005

Structures, thermal behavior, and fragmentation mechanisms of exohedral and substitutional silicon-doped C60 containing 1–12 Si atoms are investigated by extensive molecular-dynamics simulations. A nonorthogonal tight-binding model is used to mimic the interatomic interactions in the doped fullerenes. Beginning from the minimum-energy structures, the temperature of the doped fullerenes is slowly increased until fragmentation takes place. A correlation can be established between the exohedral and substitutional structures and the corresponding fragmentation mechanisms and fragmentation temperatures. Exohedral C60Sim fullerenes fragment into two homonuclear pieces, the Sim cluster and the C60 fullerene that remains intact. In contrast, the substitutional C60−mSim heterofullerenes undergo structural transformations, including the partial unraveling of the cage, prior to fragmentation. Then, ejection of atoms or small molecules takes place from the distorted structures. The slow heating rate used, combined with long simulation runs, allows us to determine the fragmentation temperature of exohedral and substitutional Si-doped fullerenes as a function of the number of silicon atoms. Substitutional Si-doped fullerenes exhibit much higher fragmentation temperatures (1000–1500 K higher) than the exohedral fullerenes. This can be understood from the different bonding of the Si atoms in both structures.
Influence of an external magnetic field on the singlet and triplet emissions of tris-(8-hydroxyquinoline)aluminum(III) (Alq3)
Authors: Gärditz Christoph , Mückl Anton G. , Cölle Michael
Published: November 2005

The effect of a magnetic field on the triplet emission in Alq3 was investigated by measuring the delayed electroluminescence (EL) and the phosphorescence in Alq3-based organic light-emitting diodes and amorphous films, respectively. The change of the delayed EL intensity in amorphous Alq3 is explained by Merrifield’s theory of mutual triplet-triplet annihilation known for molecular crystals. The intensity of the instantaneous EL shows an increase of up to +4.8% depending on the magnetic-field strength, which is due to the influence of the magnetic-field on the charge balance factor and thus on the injection of minority charge carriers.
Impact of the capping layers on lateral confinement in InAs∕InP quantum dots for 1.55μm laser applications studied by magnetophotoluminescence
Authors: Cornet C. , Levallois C. , Caroff P. , Folliot H. , Labbé C. , Even J. , Le Corre A. , Loualiche S. , Hayne M. , Moshchalkov V. V.
Published: November 2005

We have used magnetophotoluminescence to study the impact of different capping layer material combinations (InP, GaInAsP quaternary alloy, or both InP and quaternary alloy) on lateral confinement in InAs∕InP quantum dots (QDs) grown on (311)B orientated substrates. Exciton effective masses, Bohr radii, and binding energies are measured for these samples. Conclusions regarding the strength of the lateral confinement in the different samples are supported by photoluminescence at high excitation power. Contrary to theoretical predictions, InAs QDs in quaternary alloy are found to have better confinement properties than InAs∕InP QDs. This is attributed to a lack of lateral intermixing with the quaternary alloy, which is present when InP is used to (partially) cap the dots. The implications of the results for reducing the temperature sensitivity of QD lasers are discussed.
Emergence of asymmetry in constructal tree flow networks
Authors: Gosselin Louis , Bejan Adrian
Published: November 2005

In this paper, we demonstrate that asymmetry in fluid distribution tree networks emerges from power requirement minimization, under global volume constraint. We have discovered several levels of asymmetry in optimal trees: different pipe lengths at the same level of branching, different mass flow rates at junctions or bifurcations, and different main branches to build the optimal dendrite. The emergence of asymmetry in optimal tree networks (man-made or natural) is a result of the optimization: it is not an assumption or a modeling feature. The constructal method that we used to discover asymmetry is predictive, and this distinguishes it from descriptive methods such as fractal geometry.