bluuebunny/crossref_metadata_2025 huggingface dataset:
Micromechanics of Tension‐Compression Asymmetry of Polycrystalline Shape‐Memory‐Alloys
Authors: Hackl K. , Zhang W. , Schmidt‐Baldassari M. , Hoppe U.
Published: April 2004

The asymmetry associated with martensitic transformations observed in tension/compression experiments of shape‐memory‐alloys (SMAs) is investigated on the basis of a recently suggested micromechanical model. The approach is based on crystallographic theory and utilizes a framework of energy minimization in a finite deformation context. Polycrystalline NiTi under tension demonstrates smaller phase‐transformation start‐strain, differe phase‐transformation stress‐levels and flatter phase‐transformation stress‐strain slopes than that under compression in our numerical simulation. The phase‐transformation start‐stress is followed to have a linear relationship with respect to the temperature within a certain range. These results agree well with experimental results reported in the literature.
An Eulerian Model for Pseudoelastic Shape Memory Alloys
Authors: Müller Ch. , Bruhns O.T.
Published: April 2004

A thermodynamic model describing pseudoelasticity is proposed. The kinematics are based on a self‐consistent Eulerian theory of finite deformations using the logarithmic rate. The thermomechanical state of the material is described by means of the mass fraction of martensite as internal state variable. From the Helmholtz free energy of the two‐phase solid, a kinetic law for the evolution of martensite is derived, taking into account the heat generated during phase transition. The material model is implemented into a finite element code in an updated Lagrangian scheme. Its parameters are calibrated to experimental data. The characteristics of the model are illustrated by simulations under different loading conditions.
Drilling of NiTi Shape Memory Alloys
Authors: Weinert K. , Petzoldt V. , Kötter D. , Buschka M.
Published: April 2004

The machinability of NiTi based shape memory alloys has been examined by conducting drilling experiments. For this reason the cutting parameters cutting speed and feed were varied within a wide range. The machining process was evaluated in terms of tool wear, cutting forces and machining quality. The tool wear was analysed with a scanning electron microscope and the influence of machining on the subsurface zone was evaluated by micro hardness measurements.
Superoxide production and the activity of MnSOD in rat brain after intrahippocampal kainate‐induced seizure
Authors: Radenovic Lidija , Jovanovic Marina , Vasiljevic Ivana , Selakovic Vesna
Published: April 2004

Glutamate neurotoxicity has been hypothesized to underlie several types of acute brain injury. Free radical reactions are implicated in a variety of physiological and pathological processes and abnormalities associated with superoxide dismutase (SOD) have been recently documented in several neurodegenerative processes. We investigated superoxide production and MnSOD activity after kainate injection into the CA3 region of the rat hippocampus. The measurements take place at different times in the hippocampus, forebrain cortex, straitum and cerebellum homogenates. Free radicals including superoxide are responsible for postlesional cytotoxicity. The increase of MnSOD in distinct brain regions, which are functionally connected via afferents and efferents, suggests that these regions are affected by the injury. It suggests that MnSOD protects the cells in these regions from superoxide‐induced damage and therefore may limit the retrograde and anterograde spread of neurotoxicity.
Laminar distribution of neurofilament inclusions and swollen achromatic neurons in neurofilament inclusion disease (NID)
Authors: Cairns N.J. , Jaros E. , Perry R.H. , Armstrong R.A.
Published: April 2004

The laminar distribution of the neurofilament inclusions (NI) and swollen achromatic neurons (SN) was studied in gyri of the temporal cortex in four patients with neurofilament inclusion disease (NID). In 84% of gyri analysed, the density of the NI was maximal in the lower cortical laminae. The distribution of the SN was more variable than the NI. Density was maximal in the lower cortex in 46% of gyri, in the upper cortical laminae in 8% of gyri, and a bimodal distribution of 15% of gyri. In the remaining gyri, there was a more even distribution of SN with cortical depth. In 31% of gyri, the vertical density of the NI was positively correlated with that of the SN. The data suggest that cortical degeneration in the temporal lobe of NID initially affects neurons in the lower laminae. Subsequently, the pathology may spread to affect much of the cortical profile, the SN preceding the appearance of the NI.
Benzodiazepines and injury: a risk adjusted model
Authors: French Dustin D. , Campbell Robert , Spehar Andrea , Angaran David M.
Published: April 2004

Background

Benzodiazepines (BZD) are one class of medications that are generally acknowledged to be a risk factor for injuries.

Objective

Our objective was to link outpatient prescription data with clinical data in order to develop a risk adjusted binary model that associates BZD usage with the risk for a healthcare encounter for an injury.

Methods

In total, 3 years of outpatient BZD prescription data, totaling 133 872 outpatient BZD prescriptions for 13 745 patients for a VA medical center, were combined with data from inpatient and outpatient administrative databases. The model incorporated Elixhauser comorbidity measures with 1‐year look back period, along with hospital discharges, marital status, age, mean arterial pressure and body mass index. The model also included the dose of the drug, converted to valium equivalents and its duration. The model was analyzed using generalized estimation equations (GEE).

Results

Dose, duration, discharges and various comorbidities were associated with an increased risk for injury, while being married reduced the risk. Increased body mass was associated with increased injury risk. Increased mean arterial pressure was associated with decreased risk.

Conclusions

These findings offer guidance on how specific combinations of risk factors and potential protective effects may impact accidental injury risk. Clinicians prescribing or adjusting BZDs can use these results to more accurately tailor medication regimens for a patient. Our findings suggest that clinicians should also consider the nature of the social support system available to the patient in assessing total injury risk. Copyright © 2004 John Wiley & Sons, Ltd.
Inverse modelling for estimating sorption and degradation parameters for pesticides
Authors: Dubus Igor G , Beulke Sabine , Brown Colin D , Gottesbüren Bernhard , Dieses Angelika
Published: April 2004

The leaching model PESTRAS was used to estimate sorption and degradation values for bentazone from three lysimeter datasets using the inverse modelling package PEST. Investigations were undertaken to assess the influence on calibration results of (1) values attributed to uncertain parameters not included in the calibration, and (2) starting values supplied to the inverse modelling package. Automatic calibrations with different realistic values for the Freundlich exponent nf yielded different combinations of Kom and DT50. Similarly, the supply of different starting values for Kom and DT50 revealed that different combinations of these two parameters equally calibrated PESTRAS for two of the three lysimeters. Examination of the error surface, ie the forward running of the model for different combinations of Kom and DT50 values, and the calculation of the goodness‐of‐fit to the experimental data, was found useful for identifying those instances where non‐uniqueness in the calibration is likely to occur. Although the derivation of sorption and degradation values through inverse modelling is expected to offer significant benefits over laboratory determinations, care should be exercised when examining values derived through this approach. Research is needed to identify data requirements for robust estimation of sorption and degradation parameters through calibration of pesticide fate models against leaching data. Copyright © 2004 Society of Chemical Industry
Pesticide adsorption in the vadose zone: a case study on Eocene and Quaternary materials in northern France
Authors: Coquet Yves , Ribière Catherine , Vachier Pierre
Published: April 2004

We present a set of adsorption coefficients measured on various Eocene and Quaternary materials sampled from the vadose zone of a catchment in Northern France for three herbicides, atrazine, isoproturon and metamitron. Some vadose zone materials were found to have higher adsorption coefficients than the topsoil. The adsorption coefficients were strongly dependent on the clay content of the material. From 83% to 97% of the variability in the adsorption coefficients could be explained by a linear relationship to the clay content. Adsorption coefficients normalized for clay content, Kclay, ranged between 1.6 and 17.6 litre kg−1 for atrazine. Neglecting the adsorption properties of the vadose zone and relying exclusively on Koc values to predict mobility may bias regional or local risk assessment of groundwater contamination by pesticides. More information on the adsorption properties of geological materials should be collected to improve our ability to predict pesticide concentrations in groundwaters. Copyright © 2004 Society of Chemical Industry
Optimizing precision overhead for x86 processors
Authors: Ogasawara Takeshi , Komatsu Hideaki , Nakatani Toshio
Published: April 2004

It is a major challenge for a Java JIT compiler to perform single‐precision floating‐point operations efficiently for the x86 processors. In previous research, the double‐precision mode is set as the default precision mode when methods are invoked. Sophisticated approaches then use heuristic approaches to optimization by considering the trade‐offs between roundings and mode switches. However, this convention introduces redundant mode switches across method boundaries. Furthermore, methods that include both single‐ and double‐precision operations cannot switch the mode, even if single‐precision operations are dominant. We propose a new approach to these problems. We eliminate redundant mode switches by ignoring the default precision mode and calling a method in the same precision mode as the caller. For methods that include both single‐ and double‐precision methods, we reduce the overhead of rounding by isolating code segments of a given method that should be executed in the single‐precision mode. We implemented our approach in IBM's Just‐in‐Time compiler, and obtained experimental results demonstrating that, in SPECjvm98, it consistently shows the best performance in any configuration of benchmark programs, inline policies, and processor architectures compared with previous research approaches. Copyright © 2004 John Wiley & Sons, Ltd.
Generation of test sequences from formal specifications: GSM 11‐11 standard case study
Authors: Bernard Eddy , Legeard Bruno , Luck Xavier , Peureux Fabien
Published: April 2004

This paper presents the results of a case study on generating test cases for a fragment of the smart card GSM 11‐11 standard. The generation method is based on an original approach using the B notation and techniques of constraint logic programming with sets. The GSM 11‐11 technical specifications were formalized with the B notation. From this B specification, a system of constraints was derived, equivalent to this formal model. Using a set constraint solver, boundary states were computed and test cases were obtained by traversing the constrained reachability graph of the specifications. The purpose of this project was to evaluate the contribution of this testing environment, called B‐TESTING‐TOOLS, in an industrial process on a real life‐size application, by comparing the generated test sequences with the already used and high‐quality manually‐designed tests. This comparison enabled us to validate our approach and showed its effectiveness in the validation process of critical applications: the case study gives a wide coverage (about 85%) of the generated tests compared to the pre‐existing tests and a saving of 30% in test design time. Copyright © 2004 John Wiley & Sons, Ltd.
Facilitating faculty learning communities: A compact guide to creating change and inspiring community
Authors: Petrone Martha C. , Ortquist‐Ahrens Leslie
Published: April 2004

Previous FLC facilitators share experiences and insights about group process and provide their advice for facilitating successful communities.
Trace element zoning in pyrite determined by PIXE elemental mapping: evidence for varying ore–fluid composition and electrochemical precipitation of gold at the Spitskop deposit, Saldania Belt, South Africa
Authors: Belcher R. W. , Rozendaal A. , Przybylowicz W. J.
Published: April 2004

The geochemistry of pyrite associated with mesothermal ‘invisible’ gold mineralization in the Neoproterozoic Saldania Belt was studied with micro‐PIXE. The petrologically observed weak zoning of pyrite was clearly visible on elemental maps generated by this analytical method. It also allowed the positive identification of two generations of pyrite. Early, irregular pre‐ to syn‐tectonic grains are As‐poor and display strongly zoned later, possibly post‐tectonic, overgrowths rich in As, Ni, Sb and Pb. This late phase also produced a generation of individual, distinctly zoned euhedral grains of similar composition. Gold is extremely fine‐grained and hosted by the zoned pyrite grains as submicroscopic specks located on the boundary between As‐poor and As‐rich bands. This association is indicative of the electrochemical precipitation of gold. Zoning of the elements Ni, Sb and Pb in the late‐stage pyrite is attributed to selective precipitation in response to changes in composition and physico‐chemical conditions of the mineralizing fluids that have been derived from devolatilization of the enclosing metamorphosed volcano‐sedimentary pile. Copyright © 2004 John Wiley & Sons, Ltd.
The most general constitutive equation in motions with constant stretch history and its approximative application in numerical simulations
Authors: Brunn P.O. , Asoud H. , Ryssel E.
Published: April 2004

In this paper we utilize the fact that in motions with constant stretch history (csh) the constitutive equation for the stress tensor can always be cast in explicit form. Great simplifications are possible in two dimensional as well as in nonswirling axisymmetric flows. For these flows one obtains the CEF equation, but the material functions depend not only on the shear rate, but on other parameters as well. For two dimensional flow this implies that the viscosity function can account for shear thinning and extension thickening. For the flow of a dilute polymer solution through a sudden contraction numerical results qualitatively agree with experimental results, quite in contrast to predictions which result if the customary generalized Newtonian fluid is used.
In Whose Interest? Pressure Group Politics, Economic Competition and Environmental Regulation
Authors: BERNAUER THOMAS , CADUFF LADINA
Published: April 2004

One school of thought in the literature on regulatory competition in environmental and consumer policy argues that inter-jurisdictional competition promotes regulatory laxity. The other highlights rent-seeking as a major driving force, implying that regulatory laxity is rare because rent-seeking is omnipresent. We observe that in most areas of environmental and consumer policy in advanced industrialized countries regulation has become much stricter since the 1970s. What then has been driving environmental and consumer risk regulation up? A popular explanation holds that large green jurisdictions have been forcing their trading partners to trade or ratchet up their regulation. In addition, political economists have developed bottom up explanations focusing on interest group politics and corporate behaviour. This article adds to the latter line by endogenising public perceptions and by exploring the effects of corporate environmental performance strategies on environmental and consumer risk policy. The empirical relevance of propositions is illustrated with case studies on growth hormones, electronic waste, and food safety.
Trading Up in the Transatlantic Relationship
Authors: PRINCEN SEBASTIAAN
Published: April 2004

This article analyses the conditions under which a race to the top or California effect is likely to take place. To that end, it examines two cases in which the EU restricted or threatened to restrict imports from the United States and Canada because of differences in regulatory standards. In one case, the European data protection directive, a California effect occurred. In the other case, the EU ban on hormone-treated beef, no California effect occurred. An analysis of these two cases leads to two additions to existing explanations of the California effect. The analysis also has a number of implications for the debate on the race to the bottom thesis.
Lithostratigraphy and volcanic evolution of Deception Island, South Shetland Islands
Authors: Smellie J.L.
Published: April 2004

Deception Island is the most active volcano in the Antarctic Peninsula region. It is a large basalt–andesite shield volcano with a 10 km-wide restless caldera (Port Foster) and a complicated history of pre- and post-caldera eruptions. There has been no modern volcanological investigation of the entire island and it remains a largely unknown volcanic hazard. The pre-caldera period on the island began with the low-energy eruption of tephras from multiple centres (Fumarole Bay Formation), possibly by subaqueous fire fountaining during shoaling and likely initial emergence of the volcano. It was followed by subaerial effusive to weakly pyroclastic (Strombolian/Hawaiian) activity that constructed a small basaltic shield (Basaltic Shield Formation), and a large eruption that vented about 30 km3 of magma (Outer Coast Tuff Formation). The latter eruption may have been triggered by an influx of compositionally different magma into the main chamber feeding the volcano, and the evidence suggests that it was associated with a significant involvement with water (seawater?). The eruption was followed by caldera collapse, and there have been several small incremental caldera “collapses” subsequently. Post-caldera eruptions were all small-volume and predominantly phreatomagmatic (Baily Head and Pendulum Cove formations), but magmatic eruptions constructed several small lava deltas around the coast and also produced a local carapace of scoria and thin lavas, particularly around the caldera rim (Stonethrow Ridge Formation). Although the caldera is presently resurging, interpretation of the eruptive history of the island suggests that future eruptions are likely to be small in volume and will have only a limited regional impact.
Age and growth of high Antarctic notothenioid fish
Authors: Mesa M. La , Vacchi M.
Published: April 2004

Available literature data on age and growth of high Antarctic fish is reviewed and discussed in relation to environmental seasonality. Except for Antarctic toothfish Dissostichus mawsoni, with maximum total length (TL) more than 170 cm, high Antarctic notothenioids are predominantly small species of less than 45 cm TL. Maximum ages reported for small Trematomus species were generally high (18–23 years), and probably comparable to those of some larger channichthyids. Highest longevity is attained by large nototheniids, such as Aethotaxis mitopteryx and D. mawsoni, of more than 30 years. Most high Antarctic fish spawn for the first time at 50–80% of maximum age. Males of some Trematomus species reach spawning maturity earlier than females, but at a higher percentage of maximum age. Pauly's index of growth performance P has been used to compare growth. P for nototheniids is typically between 1 and 2, whereas in channichthyids it is between 2 and 3. Generally, high Antarctic notothenioids exhibit a lower P than those further north. In high Antarctic nototheniids, between 19 and 42 cm maximum theoretical length, growth performance seems to increase from pelagic to benthic fish habit. Thus, although low temperature is a constraint on growth, other ecological factors linked to life style, such as food availability and physiological adaptations, may explain differences in growth performance between fish from the seasonal pack-ice zone and the high Antarctic zone.
Holocene and pre-Holocene temporary disappearance of the George VI Ice Shelf, Antarctic Peninsula
Authors: Hjort C. , Bentley M.J. , Ingólfsson Ó.
Published: April 2004

We present evidence for the absence of the George VI Ice Shelf during a brief period in the mid-Holocene and during one or more earlier interstadials or interglacials. Barnacle Bathylasma corolliforme shells sampled from ice shelf moraines at Two Step Cliffs on Alexander Island have been dated to c, 5750–6000 14C yr BP(c. 6550–6850 cal yr BP) and imply seasonally open water in the George VI Sound during this period. Other shells are beyond the range of radiocarbon dating and imply open water during one or more previous interglacial or interstadial period, prior to 40 000 14C yr BP. Our results show that the ongoing collapse of some Antarctic Peninsula ice shelves is not unprecedented.
Participation in the winter haulout by southern elephant seals (Mirounga leonina)
Authors: Kirkman S.P. , Bester M.N. , Pistorius P.A. , Hofmeyr G.J.G. , Owen R. , Mecenero S.
Published: April 2004

Southern elephant seals haulout on land to moult, breed and for a third, unknown reason, which we refer to as the winter haulout. We used long-term mark-recapture data to estimate participation levels in the winter haulout by southern elephant seals at Marion Island. There was no evidence that participation levels varied between cohorts or between years. Participation differed between sexes, with males being more likely to haulout in winter, except in the first year of life where participation was equal. Within each sex, both age and reproductive status influenced participation, but age seemed to be the most influential determinant. Generally, immature male individuals hauled out year after year in winter. The results did not allow speculation as to the purpose(s) of the winter haulout.
Estimates of sulphate reduction rates in Lake Vanda, Antarctica support the proposed recent history of the lake
Authors: Purdy K.J. , Hawes I. , Bryant C.L. , Fallick A.E. , Nedwell D.B.
Published: April 2004

Lake Vanda, a perennially ice-covered Antarctic lake has a highly stratified structure with a pronounced density gradient from 45 m and is anoxic from 68 m down. In order to gain a greater understanding of the carbon cycling in the lake we attempted to measure sulphate reduction in the summer of 1994, but rates were below detectable limits of 1.2 × 106 mol sulphate yr−1. Therefore sulphate reduction was estimated by calculating the rate of sulphide diffusion from the anoxic zone. Sulphate reduction rates were estimated to be 17.7 × 103 mol sulphate yr−1, accounting for 30% of planktonic primary production over the whole lake, but over 100% of primary productivity in the deep chlorophyll maximum. Radiocarbon dating of organic matter in the sediment (565 ± 50 yr bp), suggests that little new organic carbon reaches the sediment from the upper water column. Oxygen diffusion into the anoxic zone could account for only 44% of sulphide reoxidation; therefore, alternative oxidizing potential presumably accounted for the remainder. Sulphate concentration may be controlled by the solubility limit for a mineral phase, perhaps gypsum, as it shows a positive correlation with conductivity. The sulphur species in the anoxic zone are highly enriched in 34S (sulphate δ34S = + 42 to + 46%0, sulphide δ34S = + 13.9%0) which may be explained by either selective removal of sulphide at the oxic/anoxic interface by precipitation of metal sulphides or previous loss ofH2S to the atmosphere. While sulphate reduction is an important part of the carbon cycle within the lake, the oligotrophic nature of Lake Vanda means that all microbiological process rates are very low. The data presented suggest a dynamic and complex history for Lake Vanda and are entirely consistent with present theories of the lake's history.
An analysis of the limnology and sedimentary diatom flora of fourteen lakes and ponds from the Windmill Islands, East Antarctica
Authors: Roberts D. , McMinn A. , Johnston N. , Gore D.B. , Melles M. , Cremer H.
Published: April 2004

The limnology and sedimentary diatom flora of fourteen lakes and ponds from the Windmill Islands, East Antarctica, is presented. Saline lakes, saline ponds and freshwater ponds are represented in this dataset. The Windmill Island lake diatom flora represents an intermediate floral assemblage between that of the freshwater lakes of the Larsemann Hills and the saline lakes of Vestfold Hills, East Antarctica. Variations within this assemblage are related to water chemistry variables in the Windmill Island lakes. In particular, a lakewater salinity/phosphate gradient can explain the variation observed in the sedimentary diatom flora of the lakes and ponds included in this study.
The tanaidacean fauna of the Beagle Channel (southern Chile) and its relationship to the fauna of the Antarctic continental shelf
Authors: Schmidt Anja , Brandt Angelika
Published: April 2004

In November 1994 epibenthic sledge samples were taken in the Beagle Channel. This study presents the first systematic account of Tanaidacea of the Beagle Channel and an adjacent area on the Atlantic continental slope. The material of this part from the Magellan Strait comprised 2175 specimens and 27 species of eight families of Tanaidomorpha and two families of Apseudomorpha. Eleven species were sampled in the Magellan region for the first time. The genus Stenotanais (Anarthruridae) was reported for the first time in the Southern Hemisphere and, the bathymetric range of seven species was extended. The tanaidacean fauna in the Beagle Channel is highly heterogeneous with 36 tanaidacean species now known from the Magellan region. On the basis of a zoogeographic comparison of the Magellan region with sub-Antarctica and Antarctica, Sieg's (1988) hypothesis of a phylogenetically young, derived Antarctic tanaidacean fauna is examined and the zoogeographic relationship between the Magellanic Tanaidacea and the Antarctic tanaidaceans is discussed.
Unexpected effects of climate change on the predation of Antarctic petrels
Authors: Franeker Jan A. Van , Creuwels Jeroen C.S. , Veer Willem Van Der , Cleland Sam , Robertson Graham
Published: April 2004

Antarctic petrels Thalassoica antarctica on Ardery Island, Antarctica (66°S, 110°E), experienced major reductions in breeding success and breeder survival over four seasons between 1984/85 and 1996/97. In 1996 the reason was revealed. A large snowdrift covered part of the study colony on the cliffs. Southern giant petrels Macronectes giganteus, normally lacking access to this area, exploited the snow for soft ‘crash landings”. After landing they waited for the disturbed birds to resettle on their nests and then used surprise to seize and kill a victim. Predation continued into the egg period, and only stopped after the snowdrift had melted. Giant petrels showed no interest in the eggs but, during the panic caused by their activities, South Polar skuas Catharacta maccormicki took the deserted eggs. Antarctic petrel mortality due to predation within the 1996/97 season amounted to 15.4% of experienced breeders, and breeding success was reduced to virtually zero. Weather data from the nearby Casey station over the 1980–96 period showed that a significant increase in precipitation has occurred, in combination with shifts in speed and direction of winds. We conclude that the decreases in breeding success and survival in earlier seasons were also related to increased snowfall and predation. Although similar predation behaviour by giant petrels has not been reported before, we think that it is long established and explains why nesting of the smaller fulmarine petrels is limited to steeper cliffs or sheltered sites. The complexity of the response seems unlikely to be predicted by our present understanding of how climate change affects ecosystems.
Influence of photoperiod on visual prey detection in the Antarctic fish Notothenia neglecta
Authors: Donatti Lucélia , Fanta Edith
Published: April 2004

Reaction to the presence of prey, after visual stimulation, was tested in the Antarctic nototheniid fish Notothenia neglecta Nybelin under four different simulated Antarctic seasons - photoperiods of 24 hours light, 22 light/2 darkness, 12 light/12 darkness, and 24 hours darkness. Live Lepidonotothen nudifrons were used for visual stimulation, with exclusion of chemical and mechanical signals. The photoperiod showed significant correlation with the number of individuals stimulated and with the latency time of the first response to the presence of prey, but not with the number of attacks or pursuits. However, there were more pursuits in darkness than in light. Notothenia neglecta presumably perceive a large spectrum of wavelengths, because they had the shortest reaction time under red light, used to simulate darkness. The tests proved that N. neglecta are capable of detecting prey using only vision, in all seasons of the year, but that the optimal reactions occur in a photoperiod corresponding to the Antarctic autumn or spring.
Demography of krill in the Elephant Island area during summer 2001 and its significance for stock recruitment
Authors: Siegel V. , Bergström B. , Mühlenhardt-Siegel U. , Thomasson M.
Published: April 2004

A net sampling survey was carried out for krill in a standard station grid around Elephant Island during 27 January to 4 February 2001. In comparison with recent years the station grid was extended south, where a large proportion of small size classes, one-year-old juvenile krill was found. Results show a spatial separation of the juvenile krill and the spawning stock, Krill density was significantly higher than during the past years (229 krill 1000 m−3 or 13.0 g m−2). The proportional recruitment index for the entire survey area for the 1999/2000 year class was R1 = 0.573, which is among the highest values recorded during the past 20 years. The maturation index (based on the proportion of gravid stages) was G = 0.99, indicating an early initiation of the spawning season. The results indicate a turning point after a succession of years with poor recruitment success and low stock biomass. This is thought to be the first step for a successful spawning event and a later potential recruitment success of the 2000/01 year-class. The spatial extent of the station grid is discussed in the light of a representative coverage of the stock and the estimated recruitment index.
Palaeozoic to Mesozoic polyphase deformation of the Patuxent Range, Pensacola Mountains, Antarctica
Authors: Curtis Michael L.
Published: April 2004

The Patuxent Range forms the most southerly third of the Pensacola Mountains, East Antarctica. Largely unstudied since the original geological survey work of the 1960s, the Patuxent Range was thought to expose metasediments deformed by a single Precambrian event. However, new structural data collected from two geographically separate areas in the central Patuxent Range reveal the presence of three distinct generations of structures. A synthesis of the regional geology together with new data suggests that the Patuxent Formation was mildly deformed during end Cambrian times as part of the late stage Ross Orogeny. However, the most intense deformation, although poorly constrained in age, probably occurred during the Permo-Triassic Gondwanian Orogeny. A third phase of deformation predates the intrusion of 183 Ma lamprophyre dykes and involved an inferred vertical axis rotation of the pre-existing D1 and D2 structures and the localized development of a spaced foliation and mesoscale folding. These D3 structures may be the first evidence of an Early Jurassic deformation event in the Transantarctic Mountains, which correlates with the Peninsula and Rangitata I orogenies of the Antarctic Peninsula and New Zealand, respectively.
Formation of a Metallabicyclo[10.3.0]pentadeca-triene System: Molecular Structure of Ru3(µ3-C2Ph2C12H16)(µ-CO)2(CO)6
Authors: Bruce Michael I. , Surynt Richard J. , Skelton Brian W. , White Allan H.
Published: April 2004

The reaction between
Ru3(µ-H)(µ3-C12H15)(CO)9
and C2Ph2 affords
Ru3(µ3-C2Ph2C12H16)(µ-
CO)2(CO)6, characterized by a
single-crystal X-ray structure determination. Addition of the alkyne to the
cluster-bonded C12 ligand gives a bicyclic 12/5
system incorporating the central ruthenium atom of a bent
Ru3 chain.
Development of innate CD4+α-chain variable gene segment 24 (Vα24) natural killer T cells in the early human fetal thymus is regulated by IL-7
Authors: Sandberg Johan K. , Stoddart Cheryl A. , Brilot Fabienne , Jordan Kimberly A. , Nixon Douglas F.
Published: April 2004

Natural killer (NK) T cells are innate CD1d-restricted immune cells involved in regulation of immune tolerance, tumor immunity, and immunity to infectious pathogens. Human α-chain variable gene segment 24 (Vα24) NK T cells exist in the periphery as two functionally distinct subsets: one CD4+and one CD4-subset. However, the developmental pathway of human Vα24 NK T cells is not well understood. Here, we show that Vα24 NK T cells develop in the fetal thymus. The relative number of intrathymic NK T cell precursors decline in a linear manner with gestational age, and they are very rare in the neonatal thymus, indicating that these cells preferentially develop in the early fetal thymus. Their restriction element, CD1d, is expressed by a vast majority of thymocytes. A majority of intrathymic Vα24 NK T cell progenitors are CD4+, whereas a minority are CD4/8+/+. CD4+Vα24 NK T cell precursors show features of mature NK T cells, such as high levels of their semiinvariant T cell receptor and CD3 and some expression of CD161, whereas the CD4/8+/+precursors seem less mature. The cytokine IL-7 shows a biphasic effect on Vα24 NK T cell progenitors in fetal thymic organ culture, with high doses driving proliferation of immature CD161-progenitors and low doses supporting survival and maturation. Thus, the data demonstrate that human Vα24 NK T cells of the CD4+, but not the CD4-, subset develop in the early fetal thymus. Furthermore, data suggest an intrathymic pathway of CD4+Vα24 NK T cell development that is regulated by IL-7.
Genome-wide transcription profile of field- and laboratory-selected dichlorodiphenyltrichloroethane (DDT)-resistant
Drosophila
Authors: Pedra J. H. F. , McIntyre L. M. , Scharf M. E. , Pittendrigh Barry R.
Published: April 2004

Genome-wide microarray analysis (Affymetrix array) was used (
i
) to determine whether only one gene, the cytochrome P450 enzyme
Cyp6g1
, is differentially transcribed in dichlorodiphenyltrichloroethane (DDT)-resistant vs. -susceptible
Drosophila
; and (
ii
) to profile common genes differentially transcribed across a DDT-resistant field isolate [

Rst(2)DDT
Wisconsin

] and a laboratory DDT-selected population [

Rst(2)DDT
91-R

]. Statistical analysis (ANOVA model) identified 158 probe sets that were differentially transcribed among

Rst(2)DDT
91-R

,

Rst(2)DDT
Wisconsin

, and the DDT-susceptible genotype Canton-S (
P
< 0.01). The cytochrome P450
Cyp6a2
and the
diazepam-binding inhibitor
gene (
Dbi
) were over transcribed in the two DDT-resistant genotypes when compared to the wild-type
Drosophila
, and this difference was significant at the most stringent statistical level, a Bonferroni correction. The list of potential candidates differentially transcribed also includes 63 probe sets for which molecular function ontology annotation of the probe sets did not exist. A total of four genes (
Cyp6a2
,
Dbi
,
Uhg1
, and
CG11176
) were significantly different (
P
< 5.6 e
-06
) between

Rst(2)DDT
91-R

and Canton-S. Additionally, two probe sets encoding
Cyp12d1
and
Dbi
were significantly different between

Rst(2)DDT
Wisconsin

and Canton-S after a Bonferroni correction. Fifty-two probe sets, including those associated with pesticide detoxification, ion transport, signal transduction, RNA transcription, and lipid metabolism, were commonly expressed in both resistant lines but were differentially transcribed in Canton-S. Our results suggest that more than
Cyp6g1
is overtranscribed in field and laboratory DDT-resistant genotypes, and the number of commonalities suggests that similar resistance mechanisms may exist between laboratory- and field-selected DDT-resistant fly lines.
The Six1 homeoprotein stimulates tumorigenesis by reactivation of cyclin A1
Authors: Coletta Ricardo D. , Christensen Kimberly , Reichenberger Kelly J. , Lamb Justin , Micomonaco Damian , Huang Lili , Wolf Douglas M. , Müller-Tidow Carsten , Golub Todd R. , Kawakami Kiyoshi , Ford Heide L.
Published: April 2004

Homeobox genes constitute a large family of transcription factors that are essential during normal development and are often dysregulated in cancer. However, the molecular mechanisms by which homeobox genes influence cancer remain largely unknown. Here we show that the tissue-restricted cyclin A1 is a transcriptional target of the Six1 homeoprotein. Both genes are expressed in the embryonic but not the terminally differentiated mammary gland, and Six1-knockout mice show a dramatic reduction of cyclin A1 in the embryonic mammary gland. In addition, both genes are reexpressed in breast cancers. Six1 overexpression increases cyclin A1 mRNA levels and activity, cell proliferation, and tumor volume, whereas Six1 down-regulation decreases cyclin A1 mRNA levels and proliferation. Overexpression of Six1 in wild-type mouse embryonic fibroblasts, but not in knockout variants lacking the cyclin A1 gene, induces cell proliferation. Furthermore, inhibition of cyclin A1 in Six1-overexpressing mammary carcinoma cells decreases proliferation. Together these results demonstrate that cyclin A1 is required for the proliferative effect of Six1. We conclude that Six1 overexpression reinstates an embryonic pathway of proliferation in breast cancer by up-regulating cyclin A1.
Projections from primary visual cortex to cytochrome oxidase thin stripes and interstripes of macaque visual area 2
Authors: Xiao Youping , Felleman Daniel J.
Published: April 2004

It has been controversial whether the cytochrome oxidase (CO)-dense blobs in primate primary visual cortex (V1) and CO-dense thin stripes in visual area 2 (V2) are parts of a cortical colorprocessing stream that is segregated from other functional streams. One of the key pieces of evidence for the segregated color stream is the previous report of specific connections between blobs and thin stripes, which is parallel to the connections between interblobs and interstripes. To study the degree of the segregation between the proposed different streams, in the current study, anatomical tracers were injected into different V2 compartments with the functional guidance of optical imaging. The spatial relationship between each labeled cell and the CO blobs in V1 were analyzed quantitatively. After tracer injections in the color-preferring modules in CO thin stripes, equal amounts of labeled cells were found in the blobs and interblobs. However, the density of the labeled cells was more than twice as high in the blobs as that in the interblobs, and most of the clusters of labeled cells partially overlapped with the blobs. Tracer injections in the interstripes labeled cells predominantly in the interblobs. Our results suggest that both the blobs and interblobs project to the thin stripes and call into question the proposition that different CO compartments in V1 and V2 are connected in parallel to form highly segregated functional streams.
The effect of reduced temperature and salinity on the blood physiology of juvenile Atlantic cod
Authors: Magill S. H. , Sayer M. D. J.
Published: April 2004

The osmolality and ionic composition of the blood of juvenile Atlantic cod Gadus morhua and their response to conditions of reduced temperature and salinity in summer‐ and winter‐acclimated individuals was investigated. Haematocrit percentage was relatively stable throughout the experimental procedures. Summer‐acclimated juvenile Atlantic cod had higher plasma osmolality than winter‐acclimated fish in ambient conditions. Plasma Na+ levels were, however, higher in winter conditions, while Cl− did not vary between seasons. Temperature reduction (12, 9 and 6° C in summer and to 6 and 4° C in winter) induced a significant response in plasma osmolality and Na+ levels in summer, but only in Na+ levels in winter‐acclimated fish. A pronounced effect was seen in the summer 6° C treatment. Salinity treatments (24, 16 and 8) had a significant effect on almost all the variables in both summer and winter and resulted generally in dilution of ionic and osmotic concentrations of the plasma. This effect was pronounced in the lowest temperature treatments, with the greatest reduction observed in the summer 6° C treatment. This could suggest that winter‐acclimated fish are physiologically adapted to cope with lower seawater temperatures as opposed to summer‐acclimated fish.
Variation in the sex ratio, size and age of longfinned eels within and among coastal catchments of south‐eastern Australia
Authors: Walsh C. T. , Pease B. C. , Booth D. J.
Published: April 2004

Longfinned eels Anguilla reinhardtii were captured by both fishery‐dependent and independent sampling methods from three rivers in New South Wales, south‐eastern Australia. Sex ratios, catch per unit effort and population age and total length structure were examined in three zones (fresh water and upper and lower tidal) in the Hacking, Hawkesbury and Clarence Rivers. Females were found in relatively high proportions in all zones, ranging from 97% in a freshwater (non‐tidal) site down to 59% in a tidal site. Males were found primarily in tidal zones (only two of the 677 longfinned eels caught in non‐tidal fresh water were males), with the greatest proportions being found in the brackish upper tidal areas. The mean number of fish captured per trap was higher in the fresh water and upper tidal zones than in the lower tidal zones. The mean ± s.e. age, 17·9 ± 0·3 years, and age range, 5–52 years for females were significantly higher than those of males 12·2 ± 0·4 years; range 5–22 years, which is typical of other anguillid species. Longfinned eels captured in fresh water were found be significantly larger and older than those in tidal zones due to the almost exclusive predominance of females.
Does size matter? Assessment and fighting in small and large size‐matched pairs of adult male convict cichlids
Authors: Leiser J. K. , Gagliardi J. L. , Itzkowitz M.
Published: April 2004

Contests between matched pairs of sexually mature convict cichlids Archocentrus nigrofasciatus were staged to determine if size alone affected the ways in which the males fought. Both small and large contests began with a period of visual displays. As fights progressed, displays diminished, and were replaced by more escalated behaviours. Small and large contests were also of similar duration. Despite these consistencies with sequential assessment, large and small contests were not entirely alike. For example, large males engaged in more lateral displays and were slower to escalate than small males. Small males displayed less and escalated to biting sooner than large males. Two possible explanations are suggested for these contrasts in contest structure: absolute opponent size and differences in the males’ ages coupled with differences in experience.
Predation of whiting and haddock on sandeel: aggregative response, competition and diel periodicity
Authors: Temming A. , Götz S. , Mergardt N. , Ehrich S.
Published: April 2004

The predation of haddock Melanogrammus aeglefinus and whiting Merlangius merlangus on sandeel Ammodytes marinus was investigated based on intensive sampling [performed with a bottom trawl (GOV) equipped with a small meshed codend cover; sediment samples were taken with a van Veen grab] in a restricted area of c. 15 × 20 nautical miles in the northern North Sea during a 5 day period in July 1996. The analysis of the spatial distribution of predators revealed a pronounced aggregation of whiting in the south‐west part of the area, where sandeel catches were also highest. This pattern was thought to be the result of an aggregative behaviour of whiting. The sandeel concentration most likely reflected a restricted patch of coarse sediment of the preferred grain size for sandeels to bury in. In haddock the aggregation was less obvious. Both predators fed almost exclusively on sandeel in the south‐west part of the area with haddock stomachs containing more sandeel than whiting stomachs. The stomach contents in both predators increased rapidly during the night, indicating that the predators were targeting burying sandeels. This would explain the competitive advantage of the benthivorous haddock.
The function of agonistic display behaviours in Gnathonemus petersii
Authors: Terleph T. A.
Published: April 2004

In pairs of interacting Gnathonemus petersii, a mormyrid electric fish, dominant individuals were larger (longer body). Pairs of interacting fish of similar body size emitted more parallel displays at the onset of an interaction. Over the course of 10 min interactions, head butting increased and parallel display decreased. This decrease occurred primarily in pairs that contained a prior resident and intruder, as compared with two intruders. The patterns of electric organ discharge during parallel display, and the possible sensory modalities mediating this behaviour are discussed.
Autologous transfusion techniques: a systematic review of their efficacy
Authors: Carless P. , Moxey A. , O'Connell D. , Henry D.
Published: April 2004

summary Shortages of donor blood and fears of transmitted infections have prompted the use of a range of blood‐sparing techniques in the peri‐operative period. We conducted a systematic review of three techniques that involve the re‐infusion of a patient's blood – pre‐operative autologous blood deposit (PAD), acute normovolaemic haemodilution (ANH) and cell salvage (CS). We examined the effects of these interventions on the need for peri‐operative allogeneic red blood cell transfusion and on clinical outcomes. Controlled clinical studies were identified by computer searches of comprehensive electronic databases and bibliographic searches of published articles.

The literature search retrieved a total of 68 randomized trials (RCTs) and 81 controlled observational studies that included data from over 34 000 individuals. In summary, the RCTs found that autologous transfusion techniques consistently reduced the frequency of allogeneic transfusions, with intervention effect sizes ranging from a relative 63% reduction (95% CI 46–74%) with PAD, to 42% (27–53%) with CS and to 31% (16–44%) with ANH. Non‐randomized studies reported larger effect sizes than RCTs. PAD increased overall transfusion rates by 30% (95% CI 12–48%) and reduced pre‐operative haemoglobin levels by an average of 1·23 g dL−1. Intervention effects were substantially reduced when these techniques were performed under transfusion protocols. Interpretation of the studies was hampered by serious methodological weaknesses, particularly inadequate randomization techniques, unblinded measurements and the subjective nature of the outcome variables. The studies reported few clinical outcome and adverse event data. Previous claims regarding reduced rates of mortality and infection with autologous transfusions were not confirmed.