bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Condensed Tannins on Leaf Processing in Mid-Latitude and Tropical Streams: A Theoretical Approach
Authors: Stout R. Jean
Published: August 2008

Differences in the dynamics of allochthonous leaf processing in tropical streams are compared with those at mid-latitudes. Phytochemical differences are linked with transferral of energy in stream ecosystems. Condensed tannins, defensive secondary compounds that remain in leaves after cellular death, are suggested as inhibiting and altering leaf processing microorganisms. Comparisons between condensed tannin concentrations and leaf processing rates in mid-latitude and tropical streams support this view. Although many data are available for leaf processing rates per day in mid-latitude streams, there are few quantitative data on plant secondary compounds. The reverse is true for research in tropical regions. Leaf transfer experiments between Costa Rica and Michigan showed the interpretations based on processing rates per day may mask phytochemical differences in cross-biome studies. Processing rates normalized for temperature as degree days for such studies are preferred, as temperature differences then can be distinguished from biotic differences.
Geographic Variation in the Occurrence of Red- and White-Fleshed Chinook Salmon (Oncorhynchus tshawytscha) in Western North America
Authors: Hard Jeffrey J. , Wertheimer Alex C. , Johnson William F.
Published: August 2008

Flesh color, as reported by fishery processors, was surveyed in coded-wire tagged chinook salmon (Oncorhynchus tshawytscha) sampled from the 1983–85 Southeast Alaska commercial troll fisheries. Flesh color data were collected from 11 373 fish originating from 95 locations in western North America between southcentral Alaska and central California. White-fleshed chinook salmon were most common in stocks from coastal British Columbia, Southeast Alaska, and the tributaries of the Fraser River, British Columbia. Heterogeneity between neighboring locations was also greatest in this region, the most recently glaciated area of western North America. Differences in flesh color proportions are consistent with the hypothesis that chinook from the Pacific refuge colonized rivers in British Columbia and Southeast Alaska after the recession of the last Pleistocene glaciation. Genetic drift of populations founded by small numbers of parents is one explanation of the pattern of occurrence of white-fleshed chinook salmon. An alternate explanation is that geographic variation in the occurrence of red- and white-fleshed chinook salmon reflects evolutionary adaptations of these fish during early life history to local freshwater environments.
Mass Flux and "Nutritional Composition" of settling Epilimnetic Particles in Lake Michigan
Authors: Gardner Wayne S. , Eadie Brian J. , Chandler Joann F. , Parrish Christopher C. , Malczyk John M.
Published: August 2008

A series of sediment-trap samples, collected at a 30-m depth in southeastern Lake Michigan, was analyzed to evaluate the seasonal flux and nutritional value of settling epilimnetic particles as potential food for benthic organisms. Flux was highest in the spring (due in part to resuspension), lowest in the summer during stratification, and intermediate during autumn months. Organic content of the particles ranged from 10% ash free dry weight (AFDW) in March through May samples to 17–19% in July–August samples. During the summer, microbial degradation of organic materials occurred in the trap bottles without added preservative, as evidenced by less AFDW in nonpreserved trap bottles than in similar chloroform-preserved bottles. The percentage of AFDW occuring as lipid ranged from 3.5% in April–May up to 14% during May through August. Dominant lipid classes were hydrocarbons, polar lipids including phospholipids and chlorophyll a, and free fatty acids. The ratio of n-alkane C-17 (algal indicator) to n-alkane C-29 (terrestrial or resuspension indicator) and the ratio of biogenic silica to AFDW in preserved samples both reached a maximum in May, shortly before lipid content peaked in the benthic amphipod, Pontoporeia hoyi. This observation agrees with the hypothesis that P. hoyi receives much of its nutrition from the spring algal bloom.
Effects of Food Removal on Nutrient Release Rates and Lipid Content of Lake Michigan Pontoporeia hoyi
Authors: Gauvin Jeffery M. , Gardner Wayne S. , Quigley Michael A.
Published: August 2008

Pontoporeia hoyi, the dominant benthic invertebrate in the upper Great Lakes, appears to be well adapted to environments with seasonal inputs of high-quality food such as those supplied by the spring diatom bloom. Ammonium and phosphate excretion rates and lipid content were examined in P. hoyi under the following conditions: (1) field animals sampled seasonally, (2) food-deprived animals in filtered lake water, and (3) control animals held in native sediments without new food inputs. Nutrient excretion rates for P. hoyi (0.5 to 2 nmole NH4 (milligrams dry weight)−1∙h−1 and 0 to 0.15 nmole PO4 (milligrams dry weight)−1∙h−1) were low relative to rates previously reported for other benthic and pelagic invertebrates and varied little among the three treatment groups. In contrast to the animals held in the laboratory without new food inputs, field-collected P. hoyi accumulated increased levels of lipids following the spring diatom bloom. However, after lipid levels in field animals peaked in May, they decreased during the rest of the season at rates similar to those of starved and control animals. P. hoyi's low nutrient-excretion rates, and its ability to accumulate and store energy as lipids, for periods when food is not abundant, appear to be important factors allowing this animal to thrive in temperate lakes with spring diatom blooms.
Determination of Picogram Levels of Methylmercury by Aqueous Phase Ethylation, Followed by Cryogenic Gas Chromatography with Cold Vapour Atomic Fluorescence Detection
Authors: Bloom Nicolas
Published: August 2008

A technique is presented, which allows the rapid and precise determination of methylmercury in aqueous samples. The sample is first reacted with sodium tetraethylborate, to convert the nonvolatile monomethyl mercury to gaseous methylethylmercury. The volatile adduct is then purged from solution, and recollected on a graphitic carbon column at room temperature. The methylethylmercury is then thermally desorbed from the column, and analyzed by cryogenic gas chromatography with cold vapour atomic fluorescence detection. The method allows the simultaneous determination of labile Hg(II) species, through the formation of diethylmercury, and of dimethylmercury, which is not ethylated. The methylmercury detection limit is about 0.6 pg Hg, or 0.003 ng∙L−1 for a 200-mL sample. The technique has been successfully applied directly to a wide variety of freshwater samples and alkaline tissue digestates. Seawater is analyzed following a simple extraction step to separate the methylmercury from the interfering chloride matrix. Analyses of natural surface waters have shown methylmercury levels typically in the range of 0.02–0.10 ng∙L−1, with values as high as 0.64 ng∙L−1 in a polluted urban lake. Waters collected from the anoxic bottom waters of a stratified remote lake have shown methylmercury levels as high as 4 ng∙L−1 as Hg.
Mechanism and Occurrence of Focal Scale Resorption among Chum Salmon (Oncorhynchus keta) of the North Pacific Ocean
Authors: Bigler Brian
Published: August 2008

A recently documented scale characteristic of chum salmon (Oncorhynchus keta) originating from Hokkaido, Japan, has been found distributed almost exclusively among stocks of Asian origin. Scales from 10 544 chum salmon collected from 25 near-shore locations throughout the North Pacific Ocean were examined. Resorption of the scale focus, including instances where an easily visible hole had been formed, was found among 10.8% of Japanese chum salmon and 15.9% of chum salmon originating from the Soviet Union. In North America, this trait was infrequent (< 0.5%) among populations north of the Aleutian Islands, British Columbia, and Puget Sound, and was not found in Cook Inlet, Prince William Sound, and Southeast Alaska. Focal scale resorption arises from osteoclastic cellular activity, most likely following the first winter of life, and remains as a permanent mark thereafter. This unique, uniformly occurring, easily identifiable scale characteristic will provide a valuable tool for stock identification. Evidence of focal scale resorption is also reported in sockeye (O. nerka), coho (O. kisutch), and king salmon (O. tshawytscha), but was not found in pink salmon (O. gorbuscha), sampled from locations in Alaska.
Growth, Mortality, and Secondary Production in Natural Populations of the Blue Mussel, Mytilus edulis
Authors: Mallet A. L. , Carver C. E. A.
Published: August 2008

Juveniles (17–26 mm) from 11 natural populations of the blue mussel Mytilus edulis were each transplanted to nine sites along the coast of Nova Scotia, Canada. Production was determined from the growth and mortality profiles of each stock over the period from November 1985 to December 1986. Stock and stock by season explained 26.6% of the variance in production whereas site and site by season accounted for 24.1%. Stock and its interactions explained most of the variance in mortality, while site and its interactions were more important in explaining the variance in growth. Growth, rather than mortality, was the primary determinant of production.
Sigmoid Relationships between Nutrients and Chlorophyll among Lakes
Authors: McCauley Edward , Downing John A. , Watson Susan
Published: August 2008

Previous studies of freshwater eutrophication have shown that algal biomass tends to increase with the supply of dissolved phosphorus. This concept has been condensed into empirical relationships between chlorophyll a and total phosphorus concentrations (convenient measures of algal biomass and phosphorus availability) which have become essential tools in theoretical and applied limnology. With few exceptions, ecologists accept the idea that chlorophyll concentration rises linearly with phosphorus concentration among lakes. Such a suggestion runs counter to Liebigian principles of fertilization however, and contradicts laboratory and field research indicating the influence of other nutrients. Our analysis of two large independent phosphorus–chlorophyll data sets from temperate-zone lakes shows that log phosphorus–log chlorophyll relationships are sigmoid in shape and that a second nutrient, nitrogen, has a significant impact on chlorophyll concentrations when phosphorus availability is high. Our new empirical relationships indicate that mechanisms regulating algal biomass change with enrichment, and suggest new management strategies for polluted lakes.
Unifying Nutrient–Chlorophyll Relationships in Lakes
Authors: Prairie Yves T. , Duarte Carlos M. , Kalff Jacob
Published: August 2008

We used data drawn from the literature to test some basic predictions derived from nutrient limitation theory. Contrary to expectation, nitrogen was not better correlated to chlorophyll in nitrogen limited lakes (as measured by the total nitrogen:total phosphorus (TN:TP) ratio). We also examined whether the variability in published relationships between chlorophyll a (Chla) and nutrient levels in lakes can be explained by differences in the relative concentrations of nitrogen and phosphorus (TN:TP ratio). Our results show that the coefficients and precision of the Chla = f(TP) and Chla = f(TN) regression equations vary systematically and concomitantly with TN:TP ratios, and are highest for lakes with TN:TP ratios of 23–28 (by weight). These findings were confirmed with independent data and explain the variability of published Chla = f(TP) relationships. We propose a model that predicts the coefficients of Chla = f(TP) and Chla = f(TN) equations for lakes with different TN:TP ratios. This model proved useful in predicting the chlorophyll trajectories of lakes over time. The results imply an "optimal" TN:TP ratio beyond which the relative rates of increase in chlorophyll with increasing nutrient concentrations are reduced.
Pennate Diatom Nitzschia pungens as the Primary Source of Domoic Acid, a Toxin in Shellfish from Eastern Prince Edward Island, Canada
Authors: Bates S. S. , Bird C J. , Freitas A. S. W. de , Foxall R. , Gilgan M. , Hanic L. A. , Johnson G. R. , McCulloch A. W. , Odense P. , Pocklington R. , Quilliam M. A. , Sim P. G. , Smith J. C. , Rao D. V. Subba , Todd E. C. D. , Walter J. A. , Wright J. L. C.
Published: August 2008

An outbreak of food poisoning in Canada during autumn 1987 was traced to cultured blue mussels (Mytilus edulis) from the Cardigan Bay region of eastern Prince Edward Island (P.E.I.). The toxin, identified as domoic acid, had not previously been found in any shellfish and this outbreak represents the first known occurrence of human poisoning by this neurotoxin. A plankton bloom at the time of the outbreak consisted almost entirely of the pennate diatom, Nitzschia pungens f. multiseries, and a positive correlation was found between the number of N. pungens cells and the concentration of domoic acid in the plankton. Nitzschia pungens f. multiseries isolated from Cardigan Bay produced domoic acid in culture at levels (1 to 20 pg∙cell−1) comparable with values estimated for N. pungens in the plankton samples. Isolates of several Cardigan Bay phytoplankton, including the closely related species Nitzschia seriata, failed to produce domoic acid. Other Nitzschia spp. and two Amphora coffeaeformis isolates also failed to produce domoic acid. We conclude that N. pungens was the major source of the domoic acid in toxic mussels in eastern P.E.I. The recurrence, in November 1988, of a monospecific bloom of N. pungens and the presence of domoic acid in plankton and mussels reinforced this conclusion.
Spatial and Temporal Patterns of Hydrogen Peroxide in Lake Waters
Authors: Cooper W. J. , Lean D. R. S. , Carey J. H.
Published: August 2008

Depth profiles of H2O2 concentration were measured at three stations in Lake Erie, one in Lake Ontario and in Jacks Lake. Epilimnetic concentrations followed changes in solar radiation suggesting that the formation resulted from photochemical or perhaps photoautotrophic processes. Mid-day H2O2 concentrations of 100–200 nM were observed at all locations. Dark decay of H2O2, determined at several depths at two locations, followed apparent first order kinetics with half lives from 10–22 h. H2O2 may be useful as a tracer for short term mixing processes and as a powerful oxidizing agent can influence metal speciation, degradation of some organic pollutants, as well as the survival and behavior of organisms.
Mesoscale Aggregations of Euphausiid Sound Scattering Layers on the Continental Shelf of Vancouver Island
Authors: Simard Yvan , Mackas David L.
Published: August 2008

High frequency acoustics (104 kHz) and stratified (BIONESS) net tows were used to map the vertical and horizontal distribution of macrozooplankton scattering layers on and seaward of the continental shelf off Vancouver Island, in June and August of 1986. The macrozooplankton scattering layers were dominated by euphausiids, primarily Euphausia pacifica and Thysanoessa spinifera. During both surveys, dense aggregations were found in the same two general regions. The first was along the shelf break, where highest biomass was observed (averages over a few kilometres of transect reaching to about 200 mg dry weight∙m−3 = about 40 individuals∙m−3 and > 4 g dry weight∙m−2). A second, broader and more diffuse aggregation occupied the deeper southeast end of the shelf (area about 200 km2, biomass 1–2 g∙m−2). The scattering layers showed a consistent diel vertical migration. Daytime depth was deeper at the shelf break (~ 150–200 m) than on the shelf (~ 100–150 m) and occasionally extended to the bottom. These day-depths corresponded to the California Undercurrent waters of 6–7 °C, a salinity of 33.75–34‰ and sigma-T > 26.5. Distribution patterns were coincident with those of upwelled regions, high phytoplankton biomass, and high hake and herring biomass. They were also associated with the shelf break jet and the recurrent Tully eddy. There is a strong possibility of aggregation in restricted areas through the coupling of advection and vertical swimming behavior of the animals.
Foraging Mode Switches in the Golden Shiner (Notemigonus crysoleucas)
Authors: Ehlinger Timothy J.
Published: August 2008

Golden shiners (Notemigonus crysoleucas) use two distinct foraging modes when feeding on zooplankton. Shiners particulate-feed on large cladocerans, visually locating and attacking individual prey items. Shiners also pump filter-feed on high densities of small zooplankton, using no apparent visual cues to detect prey. Particulate-feeding and filter-feeding functional response curves were determined from laboratory experiments. Particulate-feeding rates on Daphnia pulex increased with shiner size, but filter-feeding rates on Bosmina decreased with shiner size. Experiments with both prey types present simultaneously revealed that shiners can switch between foraging modes on a short time scale which increases their total foraging return by filter-feeding on Bosmina in between Daphnia encounters. This behavioral flexibility has consequences for both fish and zooplankton community structure in winterkill lakes. The ability to switch feeding modes on a short time scale allows shiners to exist in lakes that are dominated by small zooplankton yet still provides a mechanism to effectively remove large cladocerans when they are encountered.
FURTHER TEST MASS CHARGING SIMULATIONS FOR ASTROD I
Authors: BAO GANG , NI WEI-TOU , SHAUL D. N. A. , ARAUJO H. M. , LIU LEI , SUMNER T. J.
Published: August 2008

The electrostatic test mass charging in the ASTROD I (Astrodynamical Space Test of Relativity using Optical Devices I) mission can affect the quality of the science data due to spurious Coulomb and Lorentz forces. To estimate the size of the resultant disturbances, credible predictions of charging rates and the charging noise are required. Using the GEANT4 software toolkit, we present a detailed Monte Carlo simulation of ASTROD I test mass charging due to exposure of the spacecraft to galactic cosmic-ray (GCR) protons and alpha particles (3 He , 4 He ) in the space environment. A positive charging rate of 33.3 e+/s at solar minimum is predicted. The predicted rate reduces by 50% at solar maximum. Based on this charging rate and factoring in the contribution of minor cosmic-ray components, we calculate the acceleration noise and stiffness associated with charging. We conclude that the acceleration noise arising from Coulomb and Lorentz effects are well below the ASTROD I acceleration noise limit at 0.1 mHz both at solar minimum and maximum. The magnitude of coherent Fourier components due to charging are also estimated.
PROGRESS OF GROUND TEST OF INERTIAL SENSOR FOR ASTROD I
Authors: ZHOU Z. B. , QU S. B. , TU H. B. , BAI Y. Z. , WU S. C. , LUO J.
Published: August 2008

An electrostatically controlled torsion pendulum has been constructed to investigate the performance of the ASTROD I inertial sensor on the ground. The twist motion of the pendulum is monitored by a capacitive transducer and controlled by an electrostatic actuator. The preliminary experimental results show that the torque resolution of the pendulum is 2 × 10-12 N m Hz-1/2 at 3 mHz. Further improvements under consideration for the inertial sensor are discussed.
CHARGE MANAGEMENT FOR LISA AND LISA PATHFINDER
Authors: SHAUL D. N. A. , ARAÚJO H. M. , ROCHESTER G. K. , SCHULTE M. , SUMNER T. J. , TRENKEL C. , WASS P.
Published: August 2008

We present an overview of charge management for LISA, including a review of the problems caused by test mass charging and development of the LISA Pathfinder charge management device.
COORBITAL RESTRICTED PROBLEM AND ITS APPLICATION IN THE DESIGN OF THE ORBITS OF THE LISA SPACECRAFT
Authors: YI ZHAOHUA , LI GUANGYU , HEINZEL GERHARD , RÜDIGER ALBRECHT , JENNRICH OLIVER , WANG LI , XIA YAN , ZENG FEI , ZHAO HAIBIN
Published: August 2008

On the basis of many coorbital phenomena in astronomy and spacecraft motion, a dynamics model is proposed in this paper — treating the coorbital restricted problem together with method for obtaining a general approximate solution. The design of the LISA spacecraft orbits is a special 2+3 coorbital restricted problem. The problem is analyzed in two steps. First, the motion of the barycenter of the three spacecraft is analyzed, which is a planar coorbital restricted three-body problem. And an approximate analytical solution of the radius and the argument of the center is obtained consequently. Secondly, the configuration of the three spacecraft with minimum arm-length variation is analyzed. The motion of a single spacecraft is a near-planar coorbital restricted three-body problem, allowing approximate analytical solutions for the orbit radius and the argument of a spacecraft. Thus approximative expressions for the arm-length are given.
METHODS FOR ORBIT OPTIMIZATION FOR THE LISA GRAVITATIONAL WAVE OBSERVATORY
Authors: LI GUANGYU , YI ZHAOHUA , HEINZEL GERHARD , RÜDIGER ALBRECHT , JENNRICH OLIVER , WANG LI , XIA YAN , ZENG FEI , ZHAO HAIBIN
Published: August 2008

The Laser Interferometer Space Antenna (LISA) mission is a joint ESA-NASA mission for detecting low-frequency gravitational waves in the frequency range from 0.1 mHz to 1 Hz, by using accurate distance measurements with laser interferometry between three spacecraft, which will be launched around 2015 and one year later reach their orbits around the Sun. In order to operate successfully, it is crucial for the constellation of the three spacecraft to have extremely high stability. In this paper, several problems of the orbit optimization of the LISA constellation are discussed by using numerical and analytical methods for satisfying the requirements of accuracy. On the basis of the coorbital restricted problem, analytical expressions of the heliocentric distance and the trailing angle to the Earth of the constellation's barycenter are deduced, with the result that the approximate analytical solution of first order will meet the accuracy requirement of the spacecraft orbit design. It is proved that there is a value of the inclination of the constellation plane that will make the variation of the arm-length a minimum. The principle for selecting the optimum starting elements of orbits at any epoch is proposed. The method and programming principles of finding the optimized orbits are also presented together with examples of the optimization design.
SOME WORD ORDER BIASES FROM LIMITED BRAIN RESOURCES: A MATHEMATICAL APPROACH
Authors: FERRER-I-CANCHO RAMON
Published: August 2008

In this paper, we propose a mathematical framework for studying word order optimization. The framework relies on the well-known positive correlation between cognitive cost and the Euclidean distance between the elements (e.g. words) involved in a syntactic link. We study the conditions under which a certain word order is more economical than an alternative word order by proposing a mathematical approach. We apply our methodology to two different cases: (a) the ordering of subject (S), verb (V) and object (O), and (b) the covering of a root word by a syntactic link. For the former, we find that SVO and its symmetric, OVS, are more economical than OVS, SOV, VOS and VSO at least 2/3 of the time. For the latter, we find that uncovering the root word is more economical than covering it at least 1/2 of the time. With the help of our framework, one can explain some Greenbergian universals. Our findings provide further theoretical support for the hypothesis that the limited resources of the brain introduce biases toward certain word orders. Our theoretical findings could inspire or illuminate future psycholinguistics or corpus linguistics studies.
THE EFFECT OF TIME SCALE DIFFERENCES AND TIME DELAYS ON THE STRUCTURAL STABILITY OF OSCILLATIONS IN A TWO-GENE NETWORK
Authors: RADDE NICOLE
Published: August 2008

Biological networks are often modeled by systems of ordinary differential equations. In chemical reaction kinetics, for instance, sigmoid functions represent the regulation of gene expression via transcription factors. Solutions of these models tend to converge to a unique steady state, and feedback control mechanisms are required for a more complex dynamic behavior.

This paper focuses on periodic behavior in two-component regulatory networks. Here, a key issue is that oscillations in chemical reaction systems are usually not robust with respect to parameter variations. Small variations lead to bifurcations that change the system's overall qualitative dynamic behavior. This concerns the mechanisms stabilizing periodic behavior in living cells. Using a small sample network, we demonstrate that oscillations can efficiently be stabilized by large time scale differences that correspond to reactions with different velocities. Furthermore, the inclusion of a time delay, reflecting transport and diffusion processes, has a similar effect. This suggests that processes of this kind potentially play a crucial role in biological oscillators.
The Palaeo-Tokyo Bay concept
Authors: Yajima Michiko
Published: August 2008

Tokyo is situated in the southern part of the Kanto Plain, the largest plain in Japan. It is filled with thick marine Quaternary sediments deposited in the Palaeo-Tokyo Bay. The concept of a Palaeo-Tokyo Bay was proposed by
Hisakatsu Yabe in 1913
and
1914
, based on molluscan fossils, geography and tectonics. Palaeo-Tokyo Bay used to open to the east and, at the time of the high sea-level phase, perhaps also to the south, whereas the modern Tokyo Bay opens to the south. The Paleao-Tokyo Bay concept is supported by recent sedimentological evidence, sequence stratigraphy and tectonic studies, and is considered to have formed in a forearc basin near the triple junction of plates (the Pacific, Asian and Philippine plates) and trenches (Japan Trench, Sagami Trough and Izu-Ogasawara Trench) in the Quaternary. The bay is unique and shows evidence of repeated differential vertical movements during its formation.
Australia – a Cenozoic history
Authors: Branagan David
Published: August 2008

The study of the Quaternary events that shaped the surface of Australia cannot be separated from the previous 60 Ma of the Tertiary. This history has only begun to be clearly understood since about 1950. Explorers from the late seventeenth century to the mid-nineteenth century laid the groundwork for the later understanding by their observations, particularly under difficult conditions, and by their attempts to interpret what they recorded. The western and southwestern coasts provided evidence of relative uplift of land, while the northeastern coast (the Great Barrier Reef) indicated evidence of the opposite. Explorers of various nationalities provided the evidence. Knowledge of the dry inland began to emerge from the 1830s, with puzzlement about ‘hard crusts’. Evidence of limited Pleistocene glaciation and relatively young, but quite extensive, volcanic activity took somewhat longer to evaluate. A major interest for European savants was the discovery, in the late 1820s, of cave deposits of extinct vertebrates.
George Leslie Adkin (1888-1964): glaciation and earth movements in the Tararua Range, North Island, New Zealand
Authors: Brook Martin S.
Published: August 2008

In the northern hemisphere the broad extent of glaciation had been mostly accepted by the start of the twentieth century, but in New Zealand at that time even the general picture of glaciation was uncertain. Julius von Haast had established that in the South Island the glaciers had extended out considerably from the Southern Alps, but the extent of glaciation in the North Island was unknown. Two rival viewpoints were put forward in 1909. James Park thought that there was a widespread ice sheet, which covered the South Island, Cook Strait and much of the North Island; Patrick Marshall thought that the extent of ice was much less, and argued that much of Park's evidence was spurious. The argument was ‘somewhat resolved’ by a young amateur geologist, Leslie Adkin, who showed that glaciation in the North Island was at most modest, and largely confined to the uppermost part of the main axial ranges. Adkin was a farmer and had no university education, but he published nearly 40 articles in scientific journals on topics as varied as Maori archaeology, and glacial and tectonic geomorphology. This article examines the evidence he adduced for the occurrence of a limited Pleistocene glaciation in the Tararua Range in the south of the North Island, and considers the role of the amateur in New Zealand geology.
Origin and development of ideas on Pliocene and Quaternary glaciations in northern and eastern Europe, Iceland, Caucasus and Siberia
Authors: Milanovsky Evgeny E.
Published: August 2008

A personal account, illustrated by the author's sketches, of ideas about glaciation, neotectonics and Quaternary geology, discussing the author's observations made during the course of his work undertaken in eastern Europe and Siberia, the Caucasus and Iceland. The paper is at the same time a contribution to autobiographical literature and to studies in the history of geoscience. The author's discovery of evidence for Pliocene glaciation in the Caucasus is noteworthy.
Quaternary research in the Baltic countries
Authors: Gaigalas Algirdas
Published: August 2008

The development of Quaternary research in the Baltic countries was determined by geopolitical position as well as by economical and social conditions, the formation of science centres, the progress of geological thought, the natural environment and the specific geological development of this area of Eastern Europe. One of the peculiarities of Baltic Quaternary research was that it was undertaken initially by French, German, Russian, English, Finnish and Polish scholars, and later by Lithuanian, Latvian and Estonian researchers. The different nationalities infused Quaternary research with a variety of ideas and methods of study. Thus, within the course of investigations of both Quaternary and bedrock geology, specific periods related to progress in science and historical events in the Baltic States can be recognized: (1) scholastic period, drift hypothesis, Ice Age, glacialism, polyglacialism (Russian Empire administration until 1914); (2) geomorphological investigations (independent republics interwar years 1918–1939); (3) detailed investigations and mapping (Soviet administration 1940–1990); and (4) modern Quaternary studies (restoration of independence of Baltic States from 1990).
Unwrap mosaics
Authors: Rav-Acha Alex , Kohli Pushmeet , Rother Carsten , Fitzgibbon Andrew
Published: August 2008

We introduce a new representation for video which facilitates a number of common editing tasks. The representation has some of the power of a full reconstruction of 3D surface models from video, but is designed to be easy to recover from
a priori
unseen and uncalibrated footage. By modelling the image-formation process as a 2D-to-2D transformation from an object's texture map to the image, modulated by an object-space occlusion mask, we can recover a representation which we term the "unwrap mosaic". Many editing operations can be performed on the unwrap mosaic, and then re-composited into the original sequence, for example resizing objects, repainting textures, copying/cutting/pasting objects, and attaching effects layers to deforming objects.
Larrabee
Authors: Seiler Larry , Carmean Doug , Sprangle Eric , Forsyth Tom , Abrash Michael , Dubey Pradeep , Junkins Stephen , Lake Adam , Sugerman Jeremy , Cavin Robert , Espasa Roger , Grochowski Ed , Juan Toni , Hanrahan Pat
Published: August 2008

This paper presents a many-core visual computing architecture code named Larrabee, a new software rendering pipeline, a manycore programming model, and performance analysis for several applications. Larrabee uses multiple in-order x86 CPU cores that are augmented by a wide vector processor unit, as well as some fixed function logic blocks. This provides dramatically higher performance per watt and per unit of area than out-of-order CPUs on highly parallel workloads. It also greatly increases the flexibility and programmability of the architecture as compared to standard GPUs. A coherent on-die 2
nd
level cache allows efficient inter-processor communication and high-bandwidth local data access by CPU cores. Task scheduling is performed entirely with software in Larrabee, rather than in fixed function logic. The customizable software graphics rendering pipeline for this architecture uses binning in order to reduce required memory bandwidth, minimize lock contention, and increase opportunities for parallelism relative to standard GPUs. The Larrabee native programming model supports a variety of highly parallel applications that use irregular data structures. Performance analysis on those applications demonstrates Larrabee's potential for a broad range of parallel computation.
Streaming multigrid for gradient-domain operations on large images
Authors: Kazhdan Michael , Hoppe Hugues
Published: August 2008

We introduce a new tool to solve the large linear systems arising from gradient-domain image processing. Specifically, we develop a streaming multigrid solver, which needs just two sequential passes over out-of-core data. This fast solution is enabled by a combination of three techniques: (1) use of second-order finite elements (rather than traditional finite differences) to reach sufficient accuracy in a single V-cycle, (2) temporally blocked relaxation, and (3) multi-level streaming to pipeline the restriction and prolongation phases into single streaming passes. A key contribution is the extension of the B-spline finite-element method to be compatible with the forward-difference gradient representation commonly used with images. Our streaming solver is also efficient for in-memory images, due to its fast convergence and excellent cache behavior. Remarkably, it can outperform spatially adaptive solvers that exploit application-specific knowledge. We demonstrate seamless stitching and tone-mapping of gigapixel images in about an hour on a notebook PC.
Spline joints for multibody dynamics
Authors: Lee Sung-Hee , Terzopoulos Demetri
Published: August 2008

Spline joints
are a novel class of joints that can model general scleronomic constraints for multibody dynamics based on the minimal-coordinates formulation. The main idea is to introduce spline curves and surfaces in the modeling of joints: We model 1-DOF joints using splines on SE(3), and construct multi-DOF joints as the product of exponentials of splines in Euclidean space. We present efficient recursive algorithms to compute the derivatives of the spline joint, as well as geometric algorithms to determine optimal parameters in order to achieve the desired joint motion. Our spline joints can be used to create interesting new simulated mechanisms for computer animation and they can more accurately model complex biomechanical joints such as the knee and shoulder.
Fast modal sounds with scalable frequency-domain synthesis
Authors: Bonneel Nicolas , Drettakis George , Tsingos Nicolas , Viaud-Delmon Isabelle , James Doug
Published: August 2008

Audio rendering of impact sounds, such as those caused by falling objects or explosion debris, adds realism to interactive 3D audiovisual applications, and can be convincingly achieved using modal sound synthesis. Unfortunately, mode-based computations can become prohibitively expensive when many objects, each with many modes, are impacted simultaneously. We introduce a fast sound synthesis approach, based on short-time Fourier Tranforms, that exploits the inherent sparsity of modal sounds in the frequency domain. For our test scenes, this "fast mode summation" can give speedups of 5--8 times compared to a time-domain solution, with slight degradation in quality. We discuss different reconstruction windows, affecting the quality of impact sound "attacks". Our Fourier-domain processing method allows us to introduce a scalable, real-time, audio processing pipeline for both recorded and modal sounds, with auditory masking and sound source clustering. To avoid abrupt computation peaks, such as during the simultaneous impacts of an explosion, we use crossmodal perception results on audiovisual synchrony to effect temporal scheduling. We also conducted a pilot perceptual user evaluation of our method. Our implementation results show that we can treat complex audiovisual scenes in real time with high quality.
Efficient multiple scattering in hair using spherical harmonics
Authors: Moon Jonathan T. , Walter Bruce , Marschner Steve
Published: August 2008

Previous research has shown that a global multiple scattering simulation is needed to achieve physically realistic renderings of hair, particularly light-colored hair with low absorption. However, previous methods have either sacrificed accuracy or have been too computationally expensive for practical use. In this paper we describe a physically based, volumetric rendering method that computes multiple scattering solutions, including directional effects, much faster than previous accurate methods. Our two-pass method first traces light paths through a volumetric representation of the hair, contributing power to a 3D grid of spherical harmonic coefficients that store the directional distribution of scattered radiance everywhere in the hair volume. Then, in a ray tracing pass, multiple scattering is computed by integrating the stored radiance against the scattering functions of visible fibers using an efficient matrix multiplication. Single scattering is computed using conventional direct illumination methods. In our comparisons the new method produces quality similar to that of the best previous methods, but computes multiple scattering more than 10 times faster.
Real-time, all-frequency shadows in dynamic scenes
Authors: Annen Thomas , Dong Zhao , Mertens Tom , Bekaert Philippe , Seidel Hans-Peter , Kautz Jan
Published: August 2008

Shadow computation in dynamic scenes under complex illumination is a challenging problem. Methods based on precomputation provide accurate, real-time solutions, but are hard to extend to dynamic scenes. Specialized approaches for soft shadows can deal with dynamic objects but are not fast enough to handle more than one light source. In this paper, we present a technique for rendering dynamic objects under arbitrary environment illumination, which does not require any precomputation. The key ingredient is a fast, approximate technique for computing soft shadows, which achieves several hundred frames per second for a single light source. This allows for approximating environment illumination with a sparse collection of area light sources and yields real-time frame rates.
Real-time smoke rendering using compensated ray marching
Authors: Zhou Kun , Ren Zhong , Lin Stephen , Bao Hujun , Guo Baining , Shum Heung-Yeung
Published: August 2008

We present a real-time algorithm calledcompensated ray marchingfor rendering of smoke under dynamic low-frequency environment lighting. Our approach is based on a decomposition of the input smoke animation, represented as a sequence of volumetric density fields, into a set of radial basis functions (RBFs) and a sequence of residual fields. To expedite rendering, the source radiance distribution within the smoke is computed from only the low-frequency RBF approximation of the density fields, since the high-frequency residuals have little impact on global illumination under low-frequency environment lighting. Furthermore, in computing source radiances the contributions from single and multiple scattering are evaluated at only the RBF centers and then approximated at other points in the volume using an RBF-based interpolation. A slice-based integration of these source radiances along each view ray is then performed to render the final image. The high-frequency residual fields, which are a critical component in the local appearance of smoke, are compensated back into the radiance integral during this ray march to generate images of high detail.

The runtime algorithm, which includes both light transfer simulation and ray marching, can be easily implemented on the GPU, and thus allows for real-time manipulation of viewpoint and lighting, as well as interactive editing of smoke attributes such as extinction cross section, scattering albedo, and phase function. Only moderate preprocessing time and storage is needed. This approach provides the first method for real-time smoke rendering that includes single and multiple scattering while generating results comparable in quality to offline algorithms like ray tracing.
Modeling anisotropic surface reflectance with example-based microfacet synthesis
Authors: Wang Jiaping , Zhao Shuang , Tong Xin , Snyder John , Guo Baining
Published: August 2008

We present a new technique for the visual modeling of spatiallyvarying anisotropic reflectance using data captured from a single view. Reflectance is represented using a microfacet-based BRDF which tabulates the facets' normal distribution (NDF) as a function of surface location. Data from a single view provides a 2D slice of the 4D BRDF at each surface point from which we fit a partial NDF. The fitted NDF is partial because the single view direction coupled with the set of light directions covers only a portion of the "half-angle" hemisphere. We complete the NDF at each point by applying a novel variant of texture synthesis using similar, overlapping partial NDFs from other points. Our similarity measure allows azimuthal rotation of partial NDFs, under the assumption that reflectance is spatially redundant but the local frame may be arbitrarily oriented. Our system includes a simple acquisition device that collects images over a 2D set of light directions by scanning a linear array of LEDs over a flat sample. Results demonstrate that our approach preserves spatial and directional BRDF details and generates a visually compelling match to measured materials.
Upright orientation of man-made objects
Authors: Fu Hongbo , Cohen-Or Daniel , Dror Gideon , Sheffer Alla
Published: August 2008

Humans usually associate an upright orientation with objects, placing them in a way that they are most commonly seen in our surroundings. While it is an open challenge to recover the functionality of a shape from its geometry alone, this paper shows that it is often possible to infer its upright orientation by analyzing its geometry. Our key idea is to reduce the two-dimensional (spherical) orientation space to a small set of orientation candidates using functionality-related geometric properties of the object, and then determine the best orientation using an assessment function of several functional geometric attributes defined with respect to each candidate. Specifically we focus on obtaining the upright orientation for man-made objects that typically stand on some flat surface (ground, floor, table, etc.), which include the vast majority of objects in our everyday surroundings. For these types of models orientation candidates can be defined according to static equilibrium. For each candidate, we introduce a set of discriminative attributes linking shape to function. We learn an assessment function of these attributes from a training set using a combination of Random Forest classifier and Support Vector Machine classifier. Experiments demonstrate that our method generalizes well and achieves about 90% prediction accuracy for both a 10-fold cross-validation over the training set and a validation with an independent test set.
Fast viscoelastic behavior with thin features
Authors: Wojtan Chris , Turk Greg
Published: August 2008

We introduce a method for efficiently animating a wide range of deformable materials. We combine a high resolution surface mesh with a tetrahedral finite element simulator that makes use of frequent re-meshing. This combination allows for fast and detailed simulations of complex elastic and plastic behavior. We significantly expand the range of physical parameters that can be simulated with a single technique, and the results are free from common artifacts such as volume-loss, smoothing, popping, and the absence of thin features like strands and sheets. Our decision to couple a high resolution surface with low-resolution physics leads to efficient simulation and detailed surface features, and our approach to creating the tetrahedral mesh leads to an order-of-magnitude speedup over previous techniques in the time spent re-meshing. We compute masses, collisions, and surface tension forces on the scale of the fine mesh, which helps avoid visual artifacts due to the differing mesh resolutions. The result is a method that can simulate a large array of different material behaviors with high resolution features in a short amount of time.
Wavelet turbulence for fluid simulation
Authors: Kim Theodore , Thürey Nils , James Doug , Gross Markus
Published: August 2008

We present a novel wavelet method for the simulation of fluids at high spatial resolution. The algorithm enables large- and small-scale detail to be edited separately, allowing high-resolution detail to be added as a post-processing step. Instead of solving the Navier-Stokes equations over a highly refined mesh, we use the wavelet decomposition of a low-resolution simulation to determine the location and energy characteristics of missing high-frequency components. We then synthesize these missing components using a novel incompressible turbulence function, and provide a method to maintain the temporal coherence of the resulting structures. There is no linear system to solve, so the method parallelizes trivially and requires only a few auxiliary arrays. The method guarantees that the new frequencies will not interfere with existing frequencies, allowing animators to set up a low resolution simulation quickly and later add details without changing the overall fluid motion.
Anisotropic noise
Authors: Goldberg Alexander , Zwicker Matthias , Durand Frédo
Published: August 2008

Programmable graphics hardware makes it possible to generate procedural noise textures on the fly for interactive rendering. However, filtering and antialiasing procedural noise involves a tradeoff between aliasing artifacts and loss of detail. In this paper we present a technique, targeted at interactive applications, that provides high-quality anisotropic filtering for noise textures. We generate noise tiles directly in the frequency domain by partitioning the frequency domain into oriented subbands. We then compute weighted sums of the subband textures to accurately approximate noise with a desired spectrum. This allows us to achieve high-quality anisotropic filtering. Our approach is based solely on 2D textures, avoiding the memory overhead of techniques based on 3D noise tiles. We devise a technique to compensate for texture distortions to generate uniform noise on arbitrary meshes. We develop a GPU-based implementation of our technique that achieves similar rendering performance as state-of-the-art algorithms for procedural noise. In addition, it provides anisotropic filtering and achieves superior image quality.
Programmable aperture photography
Authors: Liang Chia-Kai , Lin Tai-Hsu , Wong Bing-Yi , Liu Chi , Chen Homer H.
Published: August 2008

In this paper, we present a system including a novel component called programmable aperture and two associated post-processing algorithms for high-quality light field acquisition. The shape of the programmable aperture can be adjusted and used to capture light field at full sensor resolution through multiple exposures without any additional optics and without moving the camera. High acquisition efficiency is achieved by employing an optimal multiplexing scheme, and quality data is obtained by using the two post-processing algorithms designed for self calibration of photometric distortion and for multi-view depth estimation. View-dependent depth maps thus generated help boost the angular resolution of light field. Various post-exposure photographic effects are given to demonstrate the effectiveness of the system and the quality of the captured light field.