bluuebunny/crossref_metadata_2025 huggingface dataset:
Detailed Documentation of a Holocene Sea-Level Record in the Perth Region, Southern Western Australia
Authors: Searle D. J. , Woods P. J.
Published: December 2004

Holocene prograded coastal sequences at Becher/Rockingham, southern Western Australia, contain a detailed record of sea level over the last 6400 yr. Radiocarbon dating and use of a distinct stratigraphic indicator as a sea-level marker permit reconstruction of sea-level history and suggest that the sea was at least 2.5 m above present datum about 6400 yr B.P. before falling to its present level. No evidence was found for eustatic fluctuations of the scale proposed by R. W. Fairbridge [1961,in“Physics and Chemistry of the Earth” (L. H. Ahrens, F. Press, K. Rankema, and S. K. Runcorn, Eds.), Vol. 4, pp. 99–185, Pergamon, Oxford]. The sea-level record preserved on this coast can be explained by hydro-isostasy, tectonism, or eustasy, acting individually or in concert. Without a fixed reference point or analogous data from other locations, a firm conclusion on which mechanism(s) has(have) operated could not be reached. Published sea-level data from this and other coasts are often insufficiently detailed to compare with this study. Application of the techniques of this study to analogous sedimentary sequences elsewhere will provide data of comparable accuracy that would contribute to a more precise understanding of relative sea-level movements in the late Quaternary.
Lateral-Moraine Stratigraphy and Neoglacial History of Bugaboo Glacier, British Columbia
Authors: Osborn Gerald
Published: December 2004

Most studies of alpine glacial history have concentrated on terminal moraines, but such moraines provide dates only for maximum extents of glaciers. Some lateral moraines have the potential for providing more complete glacial histories, because deposition by distal-flank accretion may result in sequences of stacked tills. Interpretation is aided by (1) the approximation that any continuous surface within the moraine parallel to the moraine's distal flank is isochronous, (2) inset gulley-fill deposits, which provide information on ice-margin history, and (3) incorporated organic material which can be radiocarbon dated. Lateral moraine stratigraphy of Bugaboo Glacier in southeastern British Columbia suggests that the glacier was fairly close to its maximum Neoglacial extent about 2500 14C yr B.P. A slow general expansion punctuated by at least one minor retreat continued from that time and culminated probably in the last century.
Red Spruce Tree-Ring Widths and Densities in Eastern North America as Indicators of Past Climate
Authors: Conkey Laura E.
Published: December 2004

Dendroclimatological studies in eastern North America are enhanced by the use of long-time series of maximum latewood densities determined by x-ray densitometry. The densities show higher correlation from tree to tree and site to site than do ring-width measurements from the same trees. Based on the macroclimatic link thus implied, maximum density and width series of Picea rubens Sarg. from high elevations in Maine are used to reconstruct up to 310 yr of past spring temperatures at nearby climate stations. The regression equations explain from 33 to 47% of calibrated variance, and verification testing of the reconstructions produces highly significant correlations and high, positive reduction of error statistics. The climate-wood density relationships are considered in light of tree physiological factors that may explain them. Results from this study are applicable to (1) an increased understanding of the relationship of climate to the formation of wood density and (2) further development of paleoclimatological and paleoenvironmental studies via tree rings in mesic regions such as northeastern North America.
Stratigraphy and Isotope Records of Middle and Late Pleistocene Mollusks from a Continuous Corehole in the Hula Basin, Northern Jordan Valley, Israel
Authors: Moshkovitz Shimon , Magaritz Mordeckai
Published: December 2004

Morphological changes in Melanopsis shells and the sudden disappearance of Viviparus were observed in a continuous core, representing about 700,000 yr, taken from the L-12 corehole in the Hula Basin, northern Jordan Valley, Israel. Two major events in δ18O values are recorded. The first, at about 435,000 yr B.P., is accompanied by a shift in δ13C values and indicates a shallowing phase with slightly higher evaporation. This event is concurrent with the abundant occurrence of a monotypic “distorted” Melanopsis, suggesting an “ecophenotypic event” during deposition of the lake's Pleistocene lower Lacustrine beds. The second major isotopic event is evidenced in the lower part of the section as a gradual depletion in 18O toward the bottom of the corehole. Minor shifts of 1–20‰ in the oxygen isotope content along the core may represent changes in the δ18O values of the water from glacial to interglacial periods representing the major climatic cycles of the Pleistocene. Five of these cycles were observed along the core.
Sea-Level History, 45,000 to 30,000 yr B.P., Inferred from Benthic Foraminifera, Gulf St. Vincent, South Australia
Authors: Cann John H. , Belperio Antonio P. , Gostin Victor A. , Murray-Wallace Colin V.
Published: December 2004

Surficial sediments of Gulf St. Vincent, South Australia, are predominantly bioclastic, cool-temperate carbonates. Benthic foraminifera are abundant and distribution of species is closely related to water depth. For example, Massilina milletti is most common at depths ca. 40 m, while Discorbis dimidiatus is characteristics of shallow, subtidal environments. Elphidium crispum, a shallow-water species, and E. macelliforme, favoring deeper water, provide a useful numerical ratio. Their logarithmic relative abundance, in the sediment size fraction 0.50–0.25 mm, correlates strongly with water depth. Vibrocores SV 4 and SV 5 recovered undisturbed sections of Quaternary strata from the deepest part (ca. 40 m) of Gulf St. Vincent. Amino acid racemization and radiocarbon age determinations show that late Pleistocene sections of the cores were deposited over the time ca. 45,000 to 30,000 yr B.P. Species of fossil foraminifera, recovered from these sections, are mostly extant in modern Gulf St. Vincent, thus allowing paleoecological inferences of late Pleistocene sea levels. These inferred sea-level maxima can be correlated with those determined from study of Huon Peninsula coral reef terraces. Initial estimates of tectonically corrected sea levels for transgressions in Gulf St. Vincent at 40,000 and 31,000 yr B.P. are −22.5 m and −22 m, respectively. The intervening regression lowered sea level to −28 m.
South Carolina Interglacial Sites and Stage 5 Sea Levels
Authors: Hollin John T. , Hearty Paul J.
Published: December 2004

Amino acid and other studies have been made on the 30-km Pleistocene sections of the Intracoastal Waterway between Myrtle Beach and Little River, South Carolina. Our ratios differentiate the long-established Waccamaw (oldest), Canepatch, and Socastee formations. The ratios from the four laboratories that have worked in this area agree very well, and apparent conflicts with U-series dates may merely reflect an abundance of reworked corals. Our amino acid correlations with U-series coral dates in South Carolina, Bermuda, and the Mediterranean all argue that the classical Canepatch and its Horry Clay date from isotope stage 5e and not, as has been implied, from stage 7, 9, 11, or 13. Excavations and erosion have increased position-fixing problems along the Waterway, and “Canepatch” amino acid ratios and U-series dates (460,000 ± 100,000 yr B.P.) at “ICW5” may be from an older unit. The Canepatch shows the double marine transgression visible in many stage 5e deposits. Pollen shows that the second transgression occurred late in the interglaciation, and stratigraphic studies show that it reached 14 m. It therefore fits very well Antarctic ice-surge models of stage 5 sea level and climate. The Socastee adds to the evidence for one or more sea levels above 0 m late in stage 5.
Pleistocene glaciation of the King Valley, Western Tasmania, Australia
Authors: Fitzsimons Sean J. , Colhoun Eric A.
Published: December 2004

Analysis of the geomorphology, geology, and palynology of deposits in the King Valley permits the identification of four glaciations and two interglaciations and has led to a revision of the Pleistocene stratigraphy of the West Coast Range. The oldest late-Cenozoic deposits in the valley appear to predate glaciation, contain extinct pollen types, and are probably of late-Tertiary age. Overlying deposits of the Linda Glaciation show intense chemical weathering and have a reversed detrital remanent magnetization indicating deposition before 730,000 yr B.P. The highly weathered tills are conformably overlain by organic deposits of the Regency Interglaciation which show a transition from montane scrub rainforest to lowland temperate rainforest. Deposits formed during the later Moore Glaciation record advances of the King Glacier and glaciers from the West Coast Range. A pollen-bearing fluvial deposit records an interstade during this glaciation. On the basis of weathering rinds, amino acid dating, and palaeomagnetism the deposits are estimated to have formed between 730,000 and 390,000 yr B.P. The Moore Glaciation deposits are overlain by sediments of the Henty Glaciation which are believed to predate 130,000 yr B.P. These deposits record multiple advances of the King Glacier and the development of a large lake during an interstade. Deposits of the subsequent Pieman Interglaciation consist of organic fine sands and silts that record a lowland scrub rainforest. Deposits of the last (Margaret) glaciation are restricted to small areas in the northern part of the valley. Although the most recent ice advance culminated after 19,000 yr B.P., evidence of older deposits of the Margaret Glaciation suggests that an early last-glaciation ice advance may have occurred. When combined with earlier studies, the recent work in the King Valley has provided one of the more complete records of Pleistocene glaciation in the Southern Hemisphere. Comparison of the deposits with the record of glaciation in southern South America and Westland, New Zealand, suggests some similarities exist between pre-last-glaciation events and indicates that glacial events in Southern Hemisphere middle latitude areas were synchronous during the last glaciation.
Gene expression of nAChR, SNAP‐25 and GAP‐43 in skeletal muscles following botulinum toxin A injection: A study in rats
Authors: Ma Jianjun , Shen Jian , Lee Cassandra A. , Elsaidi Gamal A. , Smith Thomas L. , Walker Francis O. , Rushing Julia T. , Tan Kim H. , Koman L. Andrew , Smith Beth P.
Published: December 2004

Purpose: Botulinum toxin A (BoNT‐A) is used to manage spasticity in cerebral palsy. BoNT‐A cleaves SNAP‐25 protein, blocking acetylcholine release and weakening the muscle. Nicotinic acetylcholine receptors (nAChR) including alpha, beta, delta, gamma, and epsilon subunits, and GAP‐43 protein are associated with functional recovery of neuromuscular junctions (NMJ) following BoNT‐A. To better understand the mechanism behind this functional recovery, this study attempted to (1) document changes in NMJ morphometry following BoNT‐A, and (2) determine the gene expression of nAChR subunits, SNAP‐25, and GAP‐43 protein.

Methods: In this rat study (46 rats), 6 units/kg body weight of BoNT‐A was injected into the gastrocnimus. NMJ morphometry and the time course of gene expression of nAChR subunits, SNAP‐25, and GAP‐43 were evaluated up to 1 year post‐injection.

Results: NMJ morphometry: gutter depth was reduced vs. the control side at two months, and normalizing by 6 months following BoNT. nAChR alpha mRNA and gamma mRNA increased by 3 days, peaked at 7 days and returned to control levels; delta mRNA peaked at 3 days. Epsilon mRNA peaked by 7 days. SNAP‐25 mRNA increased from 60 to 90 days, returning to control levels by 6 months. GAP‐43 mRNA was unchanged.

Conclusions: Specific nAChR subunit mRNA expression up‐regulates and then returns to normal within two weeks, preceding changes in NMJ morphometry. Although GAP‐43 participates in nerve sprouting, no increase of GAP‐43 mRNA occurred following BoNT‐A. Delayed up‐regulation of SNAP‐25 mRNA might be associated with muscle functional recovery. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Type I and II collagen regulation of chondrogenic differentiation by mesenchymal progenitor cells
Authors: Chen C. W. , Tsai Y. H. , Deng W. P. , Shih S. N. , Fang C. L. , Burch J. G. , Chen W. H. , Lai W. F.
Published: December 2004

Chondrogenic differentiation by mesenchymal progenitor cells (MPCs) is associated with cytokines such as transforming growth factor‐beta 1 (TGF‐β1) and dexamethasone. Extracellular matrix (ECM) also regulates the differentiation by MPCs. To define whether ECM plays a functional role in regulation of the chondrogenic differentiation by MPCs, an in vitro model was used. That model exposed to dexamethasone, recombinant human TGF‐β1(rhTGF‐β1) and collagens. The results showed that MPCs incorporated with dexamethasone and rhTGF‐β1 increased proliferation and expression of glycosaminoglycan (GAG) after 14 days. Type II collagen enhanced the GAG synthesis, but did not increase alkaline phosphatase (ALP) activity. When adding dexamethasone and rhTGF‐β1 MPCs increased mRNA expression of Sox9. Incorporation with type II collagen, dexamethasone and rhTGF‐β1, MPCs induced mRNA expression of aggrecan and enhanced levels of type II collagen, and Sox9 mRNA. In contrast, incorporation with type I collagen, dexamethasone and rhTGF‐β1 MPCs reduced levels of aggrecan, and Sox9 mRNA, and showed no type II collagen mRNA. Altogether, these results indicate that type I and II collagen, in addition to the cytokine effect, may play a functional role in regulating of chondrogenic differentiation by MPCs. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
A model of melt pond evolution on sea ice
Authors: Taylor P. D. , Feltham D. L.
Published: December 2004

A one‐dimensional, thermodynamic, and radiative model of a melt pond on sea ice is presented that explicitly treats the melt pond as an extra phase. A two‐stream radiation model, which allows albedo to be determined from bulk optical properties, and a parameterization of the summertime evolution of optical properties, is used. Heat transport within the sea ice is described using an equation describing heat transport in a mushy layer of a binary alloy (salt water). The model is tested by comparison of numerical simulations with SHEBA data and previous modeling. The presence of melt ponds on the sea ice surface is demonstrated to have a significant effect on the heat and mass balance. Sensitivity tests indicate that the maximum melt pond depth is highly sensitive to optical parameters and drainage.
Observations of particle formation and growth in a mountainous forest region in central Europe
Authors: Held A. , Nowak A. , Birmili W. , Wiedensohler A. , Forkel R. , Klemm O.
Published: December 2004

In the summers of 2001 and 2002, particle formation and growth were observed at a forest ecosystem research site in the “Fichtelgebirge” mountain range in NE Bavaria, Germany. Atmospheric nucleation events, identified through detailed analysis of the time evolution of submicron particle size distributions, differed considerably from nonevent days with respect to ultrafine particle concentrations and meteorological parameters. Particle diameter growth rates, as quantified through the geometric mean diameter development of the 3–60 nm particle fraction, ranged from 2.2 to 5.7 nm h−1. While H2SO4 concentrations typically explained less than 10% of the observed growth rates, a significant fraction of particle growth may be explained through condensation of organic vapors from α‐pinene oxidation. On several days, cocondensation of H2SO4 and α‐pinene oxidation products was sufficient to fully explain the observed growth dynamics. While BVOC emissions from the tree vegetation may contribute to particle formation, the forest also acts as an effective sink for particles. This is reflected in the dominance of particle deposition to the forest over emission, with the strongest deposition fluxes occurring during particle formation events.
Accelerated electron populations formed by Langmuir wave-caviton interactions
Authors: Sircombe N. J. , Arber T. D. , Dendy R. O.
Published: December 2004

Direct numerical simulations of electron dynamics in externally driven electrostatic waves have been carried out using a relativistic two-fluid one-dimensional Vlasov–Poisson code. When the driver wave has sufficiently large amplitude, ion density holes (cavitons) form. The interaction between these cavitons and other incoming Langmuir waves gives rise to substantial local acceleration of groups of electrons, and fine jetlike structures arise in electron phase space. We show that these jets are caused by wave breaking when finite amplitude Langmuir waves experience the ion density gradient at the leading edge of the holes, and are not caused by caviton burnout. An analytical two-fluid model gives the critical density gradient and caviton depth for which this process can occur. In particular, the density gradient critically affects the rate at which a Langmuir wave, moving into the caviton, undergoes Landau damping. This treatment also enables us to derive analytical estimates for the maximum energy of accelerated electrons, and for the energy spectrum along a phase-space jet. These are confirmed by direct numerical simulations.
Shear dispersion and turbulence decorrelation by differential rotation
Authors: Garcia O. E. , Bian N. H.
Published: December 2004

The shear enhanced dispersion of a passive scalar field subject to differential rotation is investigated analytically and interpretations are given in terms of turbulence shear decorrelation. Using the method of advected coordinates, the enhanced dispersion caused by steady and oscillatory flows with uniform shear is derived and the well-known turbulence shear decorrelation theory is recovered. The additional role of kinetic energy transfer due to differential advection of vorticity is also pointed out. Finally, the shear enhanced dispersion due to flows with periodic variations in space as well as time is given. It is found that radially alternating flows may significantly reduce the turbulence decorrelation time provided the root mean square flow shear is larger than the flow oscillation frequency. In the opposite limit of fast flow oscillations there is no turbulence decorrelation.
Hi and Galaxy Formation in Loose Groups
Authors: Pisano Daniel J.
Published: December 2004

Models of hierarchical galaxy formation predict that large numbers of low-mass, dark matter halos remain around galaxies today. These models predict an order of magnitude more halos than observed stellar satellites in the Local Group. One possible solution to this discrepancy is that the high-velocity clouds (HVCs) around the Milky Way may be associated with the excess dark matter halos and be the gaseous remnants of the galaxy formation process. If this is the case, then analogues to the HVCs should be visible in other groups. In this paper, I review the observations of Hi clouds lacking stars around other galaxies and in groups, present early results from our Hi survey of loose groups analogous to the Local Group, and discuss implications for the nature of HVCs and galaxy formation.
Nav1.5 E1053K mutation causing Brugada syndrome blocks binding to ankyrin-G and expression of Nav1.5 on the surface of cardiomyocytes
Authors: Mohler Peter J. , Rivolta Ilaria , Napolitano Carlo , LeMaillet Guy , Lambert Stephen , Priori Silvia G. , Bennett Vann
Published: December 2004

We identify a human mutation (E1053K) in the ankyrin-binding motif of Nav1.5 that is associated with Brugada syndrome, a fatal cardiac arrhythmia caused by altered function of Nav1.5. The E1053K mutation abolishes binding of Nav1.5 to ankyrin-G, and also prevents accumulation of Nav1.5 at cell surface sites in ventricular cardiomyocytes. Ankyrin-G and Nav1.5 are both localized at intercalated disc and T-tubule membranes in cardiomyocytes, and Nav1.5 coimmunoprecipitates with 190-kDa ankyrin-G from detergent-soluble lysates from rat heart. These data suggest that Nav1.5 associates with ankyrin-G and that ankyrin-G is required for Nav1.5 localization at excitable membranes in cardiomyocytes. Together with previous work in neurons, these results in cardiomyocytes suggest that ankyrin-G participates in a common pathway for localization of voltage-gated Navchannels at sites of function in multiple excitable cell types.
The kinesin Eg5 drives poleward microtubule flux in Xenopus laevis egg extract spindles
Authors: Miyamoto David T. , Perlman Zachary E. , Burbank Kendra S. , Groen Aaron C. , Mitchison Timothy J.
Published: December 2004

Although mitotic and meiotic spindles maintain a steady-state length during metaphase, their antiparallel microtubules slide toward spindle poles at a constant rate. This “poleward flux” of microtubules occurs in many organisms and may provide part of the force for chromosome segregation. We use quantitative image analysis to examine the role of the kinesin Eg5 in poleward flux in metaphase Xenopus laevis egg extract spindles. Pharmacological inhibition of Eg5 results in a dose–responsive slowing of flux, and biochemical depletion of Eg5 significantly decreases the flux rate. Our results suggest that ensembles of nonprocessive Eg5 motors drive flux in metaphase Xenopus extract spindles.
Vesicles carry most exocyst subunits to exocytic sites marked by the remaining two subunits, Sec3p and Exo70p
Authors: Boyd Charles , Hughes Thom , Pypaert Marc , Novick Peter
Published: December 2004

Exocytosis in the budding yeast Saccharomyces cerevisiae occurs at discrete domains of the plasma membrane. The protein complex that tethers incoming vesicles to sites of secretion is known as the exocyst. We have used photobleaching recovery experiments to characterize the dynamic behavior of the eight subunits that make up the exocyst. One subset (Sec5p, Sec6p, Sec8p, Sec10p, Sec15p, and Exo84p) exhibits mobility similar to that of the vesicle-bound Rab family protein Sec4p, whereas Sec3p and Exo70p exhibit substantially more stability. Disruption of actin assembly abolishes the ability of the first subset of subunits to recover after photobleaching, whereas Sec3p and Exo70p are resistant. Immunogold electron microscopy and epifluorescence video microscopy indicate that all exocyst subunits, except for Sec3p, are associated with secretory vesicles as they arrive at exocytic sites. Assembly of the exocyst occurs when the first subset of subunits, delivered on vesicles, joins Sec3p and Exo70p on the plasma membrane. Exocyst assembly serves to both target and tether vesicles to sites of exocytosis.
Identification of the Arabidopsis Palmitoyl-Monogalactosyldiacylglycerol Δ7-Desaturase Gene FAD5, and Effects of Plastidial Retargeting of Arabidopsis Desaturases on the fad5 Mutant Phenotype
Authors: Heilmann Ingo , Mekhedov Sergei , King Barbara , Browse John , Shanklin John
Published: December 2004

Hexadeca 7,10,13-trienoic acid (16:3Δ7,10,13) is one of the most abundant fatty acids in Arabidopsis (Arabidopsis thaliana) and a functional component of thylakoid membranes, where it is found as an sn-2 ester of monogalactosyldiacylglycerol. The Arabidopsis fad5 mutant lacks activity of the plastidial palmitoyl-monogalactosyldiacylglycerol Δ7-desaturase FAD5, and is characterized biochemically by the absence of 16:3Δ7,10,13 and physiologically by reduced chlorophyll content and a reduced recovery rate after photoinhibition. While the fad5 mutation has been mapped, the FAD5 gene was not unambiguously identified, and a formal functional characterization by complementation of fad5 mutant phenotypes has not been reported. Two candidate genes (At3g15850 and At3g15870) predicted to encode plastid-targeted desaturases at the fad5 chromosomal locus were cloned from fad5 plants and sequenced. A nonsense mutation changing codon TGG (Trp-98) into TGA (stop) was identified in At3g15850 (ADS3), whereas the fad5 At3g15870 allele was identical to wild type (after correction of a sequencing error in the published wild-type genomic At3g15870 sequence). Expression of a genomic clone or cDNA for wild-type At3g15850 conferred on fad5 plants the ability to synthesize 16:3Δ7,10,13 and restored leaf chlorophyll content. Arabidopsis carrying a T-DNA insertion in At3g15870 had wild-type levels of both 16:3Δ7,10,13 and chlorophyll. Together, these data formally prove that At3g15850 is FAD5. Interestingly, the fad5 phenotype was partially complemented when extraplastidial Δ9-desaturases of the Arabidopsis desaturase (ADS) family were expressed as fusions with a plastidial transit peptide. Tight correlation between leaf 16:3Δ7,10,13 levels and chlorophyll content suggests a role for plastidial fatty acid desaturases in thylakoid formation.
The Arabidopsis ATR1 Myb Transcription Factor Controls Indolic Glucosinolate Homeostasis
Authors: Celenza John L. , Quiel Juan A. , Smolen Gromoslaw A. , Merrikh Houra , Silvestro Angela R. , Normanly Jennifer , Bender Judith
Published: December 2004

Plants derive a number of important secondary metabolites from the amino acid tryptophan (Trp), including the growth regulator indole-3-acetic acid (IAA) and defense compounds against pathogens and herbivores. In previous work, we found that a dominant overexpression allele of the Arabidopsis (Arabidopsis thaliana) Myb transcription factor ATR1, atr1D, activates expression of a Trp synthesis gene as well as the Trp-metabolizing genes CYP79B2, CYP79B3, and CYP83B1, which encode enzymes implicated in production of IAA and indolic glucosinolate (IG) antiherbivore compounds. Here, we show that ATR1 overexpression confers elevated levels of IAA and IGs. In addition, we show that an atr1 loss-of-function mutation impairs expression of IG synthesis genes and confers reduced IG levels. Furthermore, the atr1-defective mutation suppresses Trp gene dysregulation in a cyp83B1 mutant background. Together, this work implicates ATR1 as a key homeostatic regulator of Trp metabolism and suggests that ATR1 can be manipulated to coordinately control the suite of enzymes that synthesize IGs.
Characterization of Antirrhinum Petal Development and Identification of Target Genes of the Class B MADS Box GeneDEFICIENS [W]
Authors: Bey Melanie , Stüber Kurt , Fellenberg Kurt , Schwarz-Sommer Zsuzsanna , Sommer Hans , Saedler Heinz , Zachgo Sabine
Published: December 2004

The class B MADS box transcription factors DEFICIENS (DEF) and GLOBOSA (GLO) of Antirrhinum majus together control the organogenesis of petals and stamens. Toward an understanding of how the downstream molecular mechanisms controlled by DEF contribute to petal organogenesis, we conducted expression profiling experiments using macroarrays comprising >11,600 annotated Antirrhinum unigenes. First, four late petal developmental stages were compared with sepals. More than 500 ESTs were identified that comprise a large number of stage-specifically regulated genes and reveal a highly dynamic transcriptional regulation. For identification of DEF target genes that might be directly controlled by DEF, we took advantage of the temperature-sensitive def-101 mutant. To enhance the sensitivity of the profiling experiments, one petal developmental stage was selected, characterized by increased transcriptome changes that reflect the onset of cell elongation processes replacing cell division processes. Upon reduction of the DEF function, 49 upregulated and 52 downregulated petal target genes were recovered. Eight target genes were further characterized in detail by RT-PCR and in situ studies. Expression of genes responding rapidly toward an altered DEF activity is confined to different petal tissues, demonstrating the complexity of the DEF function regulating diverse basic processes throughout petal morphogenesis.
Arabidopsis WPP-Domain Proteins Are Developmentally Associated with the Nuclear Envelope and Promote Cell Division[W]
Authors: Patel Shalaka , Rose Annkatrin , Meulia Tea , Dixit Ram , Cyr Richard J. , Meier Iris
Published: December 2004

The nuclear envelope (NE) acts as a selective barrier to macromolecule trafficking between the nucleus and the cytoplasm and undergoes a complex reorganization during mitosis. Different eukaryotic kingdoms show specializations in NE function and composition. In contrast with vertebrates, the protein composition of the NE and the function of NE proteins are barely understood in plants. MFP1 attachment factor 1 (MAF1) is a plant-specific NE-associated protein first identified in tomato (Lycopersicon esculentum). Here, we demonstrate that two Arabidopsis thaliana MAF1 homologs, WPP1 and WPP2, are associated with the NE specifically in undifferentiated cells of the root tip. Reentry into cell cycle after callus induction from differentiated root segments reprograms their NE association. Based on green fluorescent protein fusions and immunogold labeling data, the proteins are associated with the outer NE and the nuclear pores in interphase cells and with the immature cell plate during cytokinesis. RNA interference–based suppression of the Arabidopsis WPP family causes shorter primary roots, a reduced number of lateral roots, and reduced mitotic activity of the root meristem. Together, these data demonstrate the existence of regulated NE targeting in plants and identify a class of plant-specific NE proteins involved in mitotic activity.
Diversification and Alteration of Recognition Specificity of the Pollen Ligand SP11/SCR in Self-Incompatibility of Brassica and Raphanus[W]
Authors: Sato Yutaka , Okamoto Shunsuke , Nishio Takeshi
Published: December 2004

The recognition specificity of the pollen ligand of self-incompatibility (SP11/SCR) was investigated using Brassica rapa transgenic plants expressing SP11 transgenes, and SP11 of Raphanus sativus S-21 was found to have the same recognition specificity as that of B. rapa S-9. In a set of three S haplotypes, whose sequence identities of SP11 and SRK are fairly high, R. sativus S-6 showed the same recognition specificity as Brassica oleracea S-18 and a slightly different specificity from B. rapa S-52. B. oleracea S-18, however, showed a different specificity from B. rapa S-52. Using these similar S haplotypes, chimeric SP11 proteins were produced by domain swapping. Bioassay using the chimeric SP11 proteins revealed that the incompatibility response induction activity was altered by the replacement of Region III and Region V. Pollen grains of Brassica transgenic plants expressing chimeric SP11 of the B. oleracea SP11-18 sequence with Region III and Region V from B. rapa SP11-52 (chimeric BoSP11-18[52]) were partially incompatible with the B. rapa S-52 stigmas, and those expressing the R. sativus SP11-6 sequence with Region III and Region V from B. rapa SP11-52 (chimeric RsSP11-6[52]) were completely incompatible with the stigmas having B. rapa S-52. However, the transgenic plant expressing chimeric RsSP11-6(52) also showed incompatibility with B. oleracea S-18 stigmas. These results suggest that Regions III and Region V of SP11 are important for determining the recognition specificity, but not the sole determinant. A possible process of the generation of a new S haplotype is herein discussed.
Validation of Surrogate Markers in Multiple Randomized Clinical Trials with Repeated Measurements: Canonical Correlation Approach
Authors: Alonso Ariel , Geys Helena , Molenberghs Geert , Kenward Michael G. , Vangeneugden Tony
Published: December 2004

Summary Part of the recent literature on the evaluation of biomarkers as surrogate endpoints starts from a multitrial context, which leads to a definition of validity in terms of the quality of both trial‐level and individual‐level association between the surrogate and true endpoints (Buyse et al., 2000, Biostatistics1, 49–67). These authors concentrated on cross‐sectional continuous responses. However, in many randomized clinical studies, repeated measurements are encountered on either or both endpoints. A challenge in this setting is the formulation of a simple and meaningful concept of “surrogacy.”Alonso et al. (2003, Biometrical Journal45, 931–945) proposed the variance reduction factor (VRF) to evaluate surrogacy at the individual level. They also showed how and when this concept should be extended to study surrogacy at the trial level. Here, we approach the problem from the natural canonical correlation perspective. We define a class of canonical correlation functions that can be used to study surrogacy at the trial and individual level. We show that the VRF and the

R2 measure defined by Buyse et al. (2000) follow as special cases. Simulations are conducted to evaluate the performance of different members of this family. The methodology is illustrated on data from a meta‐analysis of five clinical trials comparing antipsychotic agents for the treatment of chronic schizophrenia.
A General Model for the Analysis of Mark‐Resight, Mark‐Recapture, and Band‐Recovery Data under Tag Loss
Authors: Conn Paul B. , Kendall William L. , Samuel Michael D.
Published: December 2004

Summary Estimates of waterfowl demographic parameters often come from resighting studies where birds fit with individually identifiable neck collars are resighted at a distance. Concerns have been raised about the effects of collar loss on parameter estimates, and the reliability of extrapolating from collared individuals to the population. Models previously proposed to account for collar loss do not allow survival or harvest parameters to depend on neck collar presence or absence. Also, few models have incorporated recent advances in mark‐recapture theory that allow for multiple states or auxiliary encounters such as band recoveries. We propose a multistate model for tag loss in which the presence or absence of a collar is considered as a state variable. In this framework, demographic parameters are corrected for tag loss and questions related to collar effects on survival and recovery rates can be addressed. Encounters of individuals between closed sampling periods also can be incorporated in the analysis. We discuss data requirements for answering questions related to tag loss and sampling designs that lend themselves to this purpose. We illustrate the application of our model using a study of lesser snow geese (Chen caerulescens caerulescens).
Estimation of a Parameter and Its Exact Confidence Interval Following Sequential Sample Size Reestimation Trials
Authors: Cheng Yi , Shen Yu
Published: December 2004

Summary For confirmatory trials of regulatory decision making, it is important that adaptive designs under consideration provide inference with the correct nominal level, as well as unbiased estimates, and confidence intervals for the treatment comparisons in the actual trials. However, naive point estimate and its confidence interval are often biased in adaptive sequential designs. We develop a new procedure for estimation following a test from a sample size reestimation design. The method for obtaining an exact confidence interval and point estimate is based on a general distribution property of a pivot function of the Self‐designing group sequential clinical trial by Shen and Fisher (1999, Biometrics55, 190–197). A modified estimate is proposed to explicitly account for futility stopping boundary with reduced bias when block sizes are small. The proposed estimates are shown to be consistent. The computation of the estimates is straightforward. We also provide a modified weight function to improve the power of the test. Extensive simulation studies show that the exact confidence intervals have accurate nominal probability of coverage, and the proposed point estimates are nearly unbiased with practical sample sizes.
Modeling the Effects of a Bidirectional Latent Predictor from Multivariate Questionnaire Data
Authors: Herring Amy H. , Dunson David B. , Dole Nancy
Published: December 2004

SummaryResearchers often measure stress using questionnaire data on the occurrence of potentially stress‐inducing life events and the strength of reaction to these events, characterized as negative or positive and assigned an ordinal ranking. In studying the health effects of stress, one needs to obtain measures of an individual's negative and positive stress levels to be used as predictors. Motivated by data of this type, we propose a latent variable model, which is characterized by event‐specific negative and positive reaction scores. If the positive reaction score dominates the negative reaction score for an event, then the individual's reported response to that event will be positive, with an ordinal ranking determined by the value of the score. Measures of overall positive and negative stress can be obtained by summing the reactivity scores across the events that occur for an individual. By incorporating these measures as predictors in a regression model and fitting the stress and outcome models jointly using Bayesian methods, inferences can be conducted without the need to assume known weights for the different events. We propose an MCMC algorithm for posterior computation and apply the approach to study the effects of stress on preterm delivery.
Semiparametric Estimation of Marginal Hazard Function from Case–Control Family Studies
Authors: Hsu Li , Chen Lu , Gorfine Malka , Malone Kathleen
Published: December 2004

Summary Estimating marginal hazard function from the correlated failure time data arising from case–control family studies is complicated by noncohort study design and risk heterogeneity due to unmeasured, shared risk factors among the family members. Accounting for both factors in this article, we propose a two‐stage estimation procedure. At the first stage, we estimate the dependence parameter in the distribution for the risk heterogeneity without obtaining the marginal distribution first or simultaneously. Assuming that the dependence parameter is known, at the second stage we estimate the marginal hazard function by iterating between estimation of the risk heterogeneity (frailty) for each family and maximization of the partial likelihood function with an offset to account for the risk heterogeneity. We also propose an iterative procedure to improve the efficiency of the dependence parameter estimate. The simulation study shows that both methods perform well under finite sample sizes. We illustrate the method with a case–control family study of early onset breast cancer.
Analysis of Times to Repeated Events in Two‐Arm Randomized Trials with Noncompliance and Dependent Censoring
Authors: Matsui Shigeyuki
Published: December 2004

SummaryThis article develops randomization‐based methods for times to repeated events in two‐arm randomized trials with noncompliance and dependent censoring. Structural accelerated failure time models are assumed to capture causal effects on repeated event times and dependent censoring time, but the dependence structure among repeated event times and dependent censoring time is unspecified. Artificial censoring techniques to accommodate nonrandom noncompliance and dependent censoring are proposed. Estimation of the acceleration parameters are based on rank‐based estimating functions. A simulation study is conducted to evaluate the performance of the developed methods. An illustration of the methods using data from an acute myeloid leukemia trial is provided.
Sample Size/Power Calculation for Case–Cohort Studies
Authors: Cai Jianwen , Zeng Donglin
Published: December 2004

Summary In epidemiologic studies and disease prevention trials, interest often involves estimation of the relationship between some disease endpoints and individual exposure. In some studies, due to the rarity of the disease and the cost in collecting the exposure information for the entire cohort, a case–cohort design, which consists of a small random sample of the whole cohort and all the diseased subjects, is often used. Previous work has focused on analyzing data from the case–cohort design and few have discussed the sample size issues. In this article, we describe two tests for the case–cohort design, which can be treated as a natural generalization of log‐rank test in the full cohort design. We derive an explicit form for power/sample size calculation based on these two tests. A number of simulation studies have been used to illustrate the efficiency of the tests for the case–cohort design. An example is provided on how to use the formula.
OPEN ARCHITECTURE AND R&D INCENTIVES
Authors: Nahm Jae
Published: December 2004

In open systems, firms give up their property rights to technologies and permit other companies to use these technologies. We ask how an incumbent's architecture choice affects social welfare by altering R&D competition among firms. More specifically, we ask whether an incumbent, by adopting an open system, can establish its socially inefficient technology as the market standard, while an entrant is developing a more efficient technology. It is shown that an incumbent has an incentive to preempt an entrant's competing technology by choosing an open system, but that the open system might result in a premature market standard.
Contrasting Systems? 100 Years of Arbitration in Australia and New Zealand
Authors: Barry Michael , Wailes Nick
Published: December 2004

Supporters of collective employment regulation in New Zealand would have celebrated a centenary of arbitration a full decade before Australia, in 1994. Yet fate intervened and New Zealand’s arbitration system formally collapsed in 1991 following the introduction of the Employment Contracts Act. Despite a series of challenges during different periods, the Australian arbitration system has survived, if badly scathed, to see its 100- year anniversary. The present paper traces the historical similarities and differences in the advent, development and decline of the Australian and New Zealand systems of compulsory arbitration. Given the many structural similarities between the two systems, the paper explores important differences in the economic and political interests that both underlay the introduction and development of the two systems, and contributed to the earlier demise of the New Zealand system. The experience of the more extensive labour market reform in New Zealand provides some salutary lessons for those seeking further changes to weaken the Australian arbitration system.
Arbitration and Relations Between the Parties
Authors: Dabscheck Braham
Published: December 2004

Australia has developed a system, or systems of collective bargaining combining interactions between the parties, industrial tribunals, and political and legal processes. Arbitration has been one mechanism through which the parties have conducted their relationships. The nexus between arbitration and the parties is nuanced and fluid. It is not a simple command—obey relationship as characterised by Howard (1977) and Scherer (1985). Unions are not dependent on arbitration and tribunals have not been captured by union principles. Employer associations, in contradiction to Plowman (1988), have been proactive in pursuing the interests of employers. Following Mark Perlman (1954a, b), the successes of arbitration have been due to arbitrators being flexible and adaptable in fulfilling the diverse and changing needs of the parties. The inability of the federal tribunal to respond to the parties’ desire to adopt enterprise bargaining in the early 1990s, has resulted in a reduction in its role and influence.
Lower Branch Modes of the Compressible Boundary Layer Flow Due to a Rotating‐Disk
Authors: Turkyilmazoglu M.
Published: December 2004

In this article, a theoretical study is pursued to investigate the structure of the lower branch neutral stability modes of three‐dimensional small disturbances imposed on the compressible boundary layer flow due to a rotating‐disk. Special attention is focused on to the short‐wavelength stationary/nonstationary compressible crossflow vortex modes at sufficiently high Reynolds numbers with reasonably small scaled frequencies. Following closely the asymptotic framework introduced in [1] for the incompressible stationary modes, it is demonstrated here that the compressible modes having sufficiently long time scale can also be described by an asymptotic expansion procedure based on the triple‐deck approach. Making use of this rational asymptotic technique, which rigorously takes into account the nonparallel effects, the asymptotic structure of the nonstationary modes is shown to be adjusted by a balance between viscous and Coriolis forces, and resulted from the fact of vanishing shear stress at the disk surface, as in the incompressible Von Karman's flow. As a consequence of matching successive regions in the asymptotic procedure, it is found that the wavenumber and the orientation of the compressible lower branch modes are governed by an eigenrelation, which is akin to the one obtained previously in [1] for the incompressible stationary mode and in [2] for the compressible stationary modes. The nonparallel influences are toward destabilizing all the modes, though the wall insulation and heating are relatively stabilizing for the modes in the vicinity of the stationary mode, unlike the wall cooling. The asymptotic compressible data obtained at high Reynolds number limit compares fairly well with the numerical results generated directly solving the linearized compressible system with usual parallel flow approximation.
LIGHT INDEPENDENT CARBON FIXATION BY MARINE MACROALGAE1
Authors: Kremer Bruno P.
Published: December 2004

Several marine macroalgae representative of the Chlorophyceae, Rhodophyceae and Phaeophyceae were investigated for their potentials of photosynthesis and light independent (dark) carbon fixation. In addition, the activities of ribulose‐1,5‐bisphosphate carboxylase (RubP‐C; EC 4.1.1.39) and of phosphoenolpyruvate carboxykinase (PEP‐CK; EC 4.1.1.32) were studied. In contrast to the green and red algae investigated, all brown algae exhibited comparably high rates of dark fixation accounting for up to 20% of photosynthetic carbon uptake. These observations are confirmed by the activities of RubP‐C and PEP‐CK measured after extraction from different species and thallus regions. Dark fixed 14C was mainly recovered from aspartate, citrate, malate, glutamate, and alanine. Appreciable amounts of 14C were incorporated into insoluble (polymeric) constituents even after relatively short periods of dark fixation.
Local Government and Welfare Generosity: Municipality Spending on Social Welfare
Authors: Lien Sandra , Pettersen Per Arnt
Published: December 2004

Although it is difficult for local governments to give support for social welfare recipients top political priority, there are huge variations in the support recipients actually receive among Norwegian municipalities. However, local governments representing different party ideologies may prefer to support different dimensions of generosity. Some municipalities could have a liberal attitude to eligibility rules but be strict on time limits and the amount of money provided. Others may be generous regarding time limits or amounts received once one is accepted as a welfare client. Data from the mid 1990s indicate the variation in support is related to different generosity dimensions for different party groups. While the total number of clients seems unrelated to politics and basically correlates with local social problems, the duration and amount of support are related to the political composition of the municipality assembly. Devoid of any large variation, both time limits and the amount of support increase in accordance with socialist leanings, and the total budget used for social welfare support also increases with the proportion of women in the municipality assembly.