bluuebunny/crossref_metadata_2025 huggingface dataset:
Creating user interfaces using programming by example, visual programming, and constraints
Authors: Myers Brad A.
Published: October 2002

Peridot is an experimental tool that allows designers to create user interface components without conventional programming. The designer draws pictures of what the interface should look like and then uses the mouse and other input devices to demonstrate how the interface should operate. Peridot generalizes from these example pictures and actions to create parameterized procedures, such as those found in conventional user interface libraries such as the Macintosh Toolbox. Peridot uses visual programming, programming by example, constraints, and plausible inferencing to allow nonprogrammers to create menus, buttons, scroll bars, and many other interaction techniques easily and quickly. Peridot created its own interface and can create almost all of the interaction techniques in the Macintosh Toolbox. Therefore, Peridot demonstrates that it is possible to provide sophisticated programming capabilities to nonprogrammers in an easy-to-use manner and still have sufficient power to generate interesting and useful programs.
Receptor Kinase Signaling in Plant Development
Authors: Becraft Philip W.
Published: October 2002

▪ Abstract  The Arabidopsis genome sequence has revealed that plants contain a much larger complement of receptor kinase genes than other organisms. Early analysis of these genes revealed involvement in a diverse array of developmental and defense functions that included gametophyte development, pollen-pistil interactions, shoot apical meristem equilibrium, hormone perception, and cell morphogenesis. Amino acid sequence motifs and binding studies indicate that the ectodomains are capable of binding, either directly or indirectly, various classes of molecules including proteins, carbohydrates, and steroids. Genetic and biochemical approaches have begun to identify other components of several signal transduction pathways. Some receptor-like kinases (RLKs) appear to function with coreceptors lacking kinase domains, and genome analysis suggests this might be true for many RLKs. The KAPP protein phosphatase functions as a negative regulator of at least two RLK systems, and in vitro studies suggest it could be a common component of more. Whether plant signaling systems display a modularity similar to animal systems remains to be determined. Future efforts will reveal unknown functions of other RLKs and elucidate the relationships among their signaling networks.
Myogenic Regulatory Factors and the Specification of Muscle Progenitors in Vertebrate Embryos
Authors: Pownall Mary Elizabeth , Gustafsson Marcus K. , Emerson Charles P.
Published: October 2002

▪ Abstract  Embryological and genetic studies of mouse, bird, zebrafish, and frog embryos are providing new insights into the regulatory functions of the myogenic regulatory factors, MyoD, Myf5, Myogenin, and MRF4, and the transcriptional and signaling mechanisms that control their expression during the specification and differentiation of muscle progenitors. Myf5 and MyoD genes have genetically redundant, but developmentally distinct regulatory functions in the specification and the differentiation of somite and head muscle progenitor lineages. Myogenin and MRF4 have later functions in muscle differentiation, and Pax and Hox genes coordinate the migration and specification of somite progenitors at sites of hypaxial and limb muscle formation in the embryo body. Transcription enhancers that control Myf5 and MyoD activation in muscle progenitors and maintain their expression during muscle differentiation have been identified by transgenic analysis. In epaxial, hypaxial, limb, and head muscle progenitors, Myf5 is controlled by lineage-specific transcription enhancers, providing evidence that multiple mechanisms control progenitor specification at different sites of myogenesis in the embryo. Developmental signaling ligands and their signal transduction effectors function both interactively and independently to control Myf5 and MyoD activation in muscle progenitor lineages, likely through direct regulation of their transcription enhancers. Future investigations of the signaling and transcriptional mechanisms that control Myf5 and MyoD in the muscle progenitor lineages of different vertebrate embryos can be expected to provide a detailed understanding of the developmental and evolutionary mechanisms for anatomical muscles formation in vertebrates. This knowledge will be a foundation for development of stem cell therapies to repair diseased and damaged muscles.
Striated Muscle Cytoarchitecture: An Intricate Web of Form and Function
Authors: Clark Kathleen A. , McElhinny Abigail S. , Beckerle Mary C. , Gregorio Carol C.
Published: October 2002

▪ Abstract  Striated muscle is an intricate, efficient, and precise machine that contains complex interconnected cytoskeletal networks critical for its contractile activity. The individual units of the sarcomere, the basic contractile unit of myofibrils, include the thin, thick, titin, and nebulin filaments. These filament systems have been investigated intensely for some time, but the details of their functions, as well as how they are connected to other cytoskeletal elements, are just beginning to be elucidated. These investigations have advanced significantly in recent years through the identification of novel sarcomeric and sarcomeric-associated proteins and their subsequent functional analyses in model systems. Mutations in these cytoskeletal components account for a large percentage of human myopathies, and thus insight into the normal functions of these proteins has provided a much needed mechanistic understanding of these disorders. In this review, we highlight the components of striated muscle cytoarchitecture with respect to their interactions, dynamics, links to signaling pathways, and functions. The exciting conclusion is that the striated muscle cytoskeleton, an exquisitely tuned, dynamic molecular machine, is capable of responding to subtle changes in cellular physiology.
The Chlamydial Inclusion: Escape from the Endocytic Pathway
Authors: Fields Kenneth A. , Hackstadt Ted
Published: October 2002

▪ Abstract  Chlamydiae, bacterial obligate intracellular pathogens, are the etiologic agents of several human diseases. A large part of the chlamydial intracellular survival strategy involves the formation of a unique organelle called the inclusion that provides a protected site within which they replicate. The chlamydial inclusion is effectively isolated from endocytic pathways but is fusogenic with a subset of exocytic vesicles that deliver sphingomyelin from the Golgi apparatus to the plasma membrane. A combination of host and parasite functions contribute to the biogenesis of this compartment. Establishment of the mature inclusion is accompanied by the insertion of multiple chlamydial proteins, suggesting that chlamydiae actively modify the inclusion to define its interactions with the eukaryotic host cell. Despite being sequestered within a membrane-bound vacuole, chlamydiae clearly communicate with and manipulate the host cell from within this privileged intracellular niche.
Ionic and Cellular Basis for the Predominance of the Brugada Syndrome Phenotype in Males
Authors: Di Diego José M. , Cordeiro Jonathan M. , Goodrow Robert J. , Fish Jeffrey M. , Zygmunt Andrew C. , Pérez Guillermo J. , Scornik Fabiana S. , Antzelevitch Charles
Published: October 2002

Background—

The Brugada syndrome displays an autosomal dominant mode of transmission with low penetrance. Despite equal genetic transmission of the disease, the clinical phenotype is 8 to 10 times more prevalent in males than in females. The basis for this intriguing sex-related distinction is unknown. The present study tests the hypothesis that the disparity in expression of the Brugada phenotype is a result of a more prominent
I
to
-mediated action potential notch in the right ventricular (RV) epicardium of males versus females.

Methods and Results—

We studied epicardial tissue slices, arterially perfused wedge preparations, and dissociated epicardial myocytes isolated from male and female canine hearts. RV epicardium action potential phase 1 amplitude was 64.8±2.0% of that of phase 2 in males compared with 73.8±4.4% in females (
P
<0.05) at a cycle length of 2000 ms.
I
to
density was 26% smaller and time constant for inactivation 17% smaller at +40 mV in female versus male RV epicardial cells (
P
<0.05). The other functional characteristics of
I
to
, including the voltage dependence of inactivation and time course of reactivation, were no different between the sexes. Pinacidil caused loss of action potential dome in male, but not female, RV epicardial tissue slices. Terfenadine (5 μmol/L) induced phase 2 reentry in 6 of 7 male but only 2 of 7 female arterially perfused wedge preparations. Two of 6 male and 1 of 2 female preparations developed polymorphic ventricular tachycardia/ventricular fibrillation.

Conclusions—

Our results suggest that the predominance of the Brugada phenotype in males is a result of the presence of a more prominent
I
to
in males versus females.
Supplementation With Conjugated Linoleic Acid Causes Isomer-Dependent Oxidative Stress and Elevated C-Reactive Protein
Authors: Risérus Ulf , Basu Samar , Jovinge Stefan , Fredrikson Gunilla Nordin , Ärnlöv Johan , Vessby Bengt
Published: October 2002

Background—

Conjugated linoleic acids (CLAs), a group of fatty acids shown to have beneficial effects in animals, are also used as weight loss supplements. Recently, we reported that the
t
10
c
12 CLA-isomer caused insulin resistance in abdominally obese men via unknown mechanisms. The aim of the present study was to examine whether CLA has isomer-specific effects on oxidative stress or inflammatory biomarkers and to investigate the relationship between these factors and induced insulin resistance.

Methods and Results—

In a double-blind placebo-controlled trial, 60 men with metabolic syndrome were randomized to one of 3 groups receiving
t
10
c
12 CLA, a CLA mixture, or placebo for 12 weeks. Insulin sensitivity (euglycemic clamp), serum lipids, in vivo lipid peroxidation (determined as urinary 8-iso-PGF
2α
[F2-isoprostanes]), 15-ketodihydro PGF
2α
, plasma vitamin E, plasma C-reactive protein, tumor necrosis factor-α, and interleukin-6 were assessed before and after treatment. Supplementation with
t
10
c
12 CLA markedly increased 8-iso-PGF
2α
(578%) and C-reactive protein (110%) compared with placebo (
P
<0.0001 and
P
<0.01, respectively) and independent of changes in hyperglycemia or dyslipidemia. The increases in 8-iso-PGF
2α
, but not in C-reactive protein, were significantly and independently related to aggravated insulin resistance. Oxidative stress was related to increased vitamin E levels, suggesting a compensatory mechanism.

Conclusions—

t
10
c
12 CLA supplementation increases oxidative stress and inflammatory biomarkers in obese men. The oxidative stress seems closely related to induced insulin resistance, suggesting a link between the fatty acid-induced lipid peroxidation seen in the present study and insulin resistance. These unfavorable effects of
t
10
c
12 CLA might be of clinical importance with regard to cardiovascular disease, in consideration of the widespread use of dietary supplements containing this fatty acid.
Alternans of Atrial Action Potentials During Atrial Flutter as a Precursor to Atrial Fibrillation
Authors: Narayan Sanjiv M. , Bode Frank , Karasik Pamela L. , Franz Michael R.
Published: October 2002

Background—

The mechanisms underlying the transition of typical atrial flutter (Afl) to fibrillation (AF) remain unclear. We set out to test the hypothesis that Afl disorganizes to AF via alternans of atrial action potentials.

Methods and Results—

In 38 patients with Afl, monophasic action potentials (MAPs) were recorded at the isthmus and either high or low right atrium (HRA, LRA) during overdrive pacing to 160 ms or to the initiation of AF, whichever came first. MAP duration measured at 90% repolarization was longer at the isthmus in all patients, and failed to shorten with rate, compared with the HRA (n=38) or LRA (n=5). In 20 patients who developed AF, progressive pacing first caused alternans of isthmus MAP duration and amplitude at mean cycle length of 219±45 ms, followed by AF at a mean onset cycle length of 184±38 ms. Subsets of this group showed spontaneous action potential duration alternans at the isthmus (11 of 20 patients) and 2:1 isthmus conduction block immediately preceding AF (4 of 20 patients). In the 18 patients who did not develop AF, MAP alternans was less common (9 of 18 patients;
P
<0.0003), and occurred only at faster pacing (cycle length=169±25 ms;
P
<0.05).

Conclusions—

In patients with typical Afl, action potential duration rate maladaptation at the isthmus may lead to action potential duration alternans and conduction block preceding the transition to AF. These isthmus characteristics may enable the spontaneous initiation of AF through wavefront fractionation and may explain the benefits of isthmus ablation in preventing AF recurrence.
The Incredible Shrinking Man Essay & Board Game: a collaborative publication project
Authors:   Goat Island and the Students of the Sunflower Community School, Chicago
Published: October 2002

A creative collective known for their theatre-dance works gives TDR readers an “offshoot publication” that is both an essay and a board game.
Late Pleistocene Vertebrates and Other Fossils from Epiguruk, Northwestern Alaska
Authors: Hamilton Thomas D. , Ashley Gail M. , Reed Katherine M. , Schweger Charles E.
Published: October 2002

Sediments exposed at Epiguruk, a large cutbank on the Kobuk River about 170 km inland from Kotzebue Sound, record multiple episodes of glacial-age alluviation followed by interstadial downcutting and formation of paleosols. Vertebrate remains from Epiguruk include mammoth, bison, caribou, an equid, a canid, arctic ground squirrel, lemmings, and voles. Radiocarbon ages of bone validated by concordant ages of peat and wood span the interval between about 37,000 and 14,000 yr B.P. The late Pleistocene pollen record is dominated by Cyperaceae, with Artemisia, Salix, Betula, and Gramineae also generally abundant. The fossil record from Epiguruk indicates that the Kobuk River valley supported tundra vegetation with abundant riparian willows during middle and late Wisconsin time. Large herbivores were present during the height of late Wisconsin glaciation as well as during its waning stage and the preceding interstadial interval. The Kobuk River valley would have been a favorable refugium for plants, animals, and possibly humans throughout the last glaciation.
Deglacial Flood Origin of the Charleston Alluvial Fan, Lower Mississippi Alluvial Valley
Authors: Porter Donna A. , Guccione Margaret J.
Published: October 2002

Large-magnitude flooding of the Mississippi River from proglacial lakes Agassiz and Superior most likely occurred between 11,300 and 10,900 and 9900 and 9500 yr B.P. The Charleston alluvial fan, a depositional remnant of one of these floods, is located at the head of a wide alluvial plain near Charleston, Missouri. The fan is an elongate, convex-up sand body (16 × 24 km) composed of medium- and fine-grained sand at least 8 m thick. This sand contrasts with the older coarse-grained sand of the braided stream surface to the west and south and younger silty clay of the meandering stream level to the north and east. A weakly developed soil separates the underlying braided steam deposits from the alluvial fan. A bulk-soil radiocarbon date of 10,590 ± 200 yr B.P. from the contact between the fan and clays of the meandering stream system indicates that the Charleston fan was deposited near the end of the early interval of flooding from Lake Agassiz about 10,900 yr B.P. If the Charleston fan is the last remnant of deglacial flooding in the lower Mississippi Valley, then deposition of significant quantities of sediment from largemagnitude floods between 10,000 and 9500 yr B.P. did not extend into the lower Mississippi Valley through Thebes Gap.
Late Wisconsinan Vegetation and Environment of the Tunica Hills Region, Louisiana/Mississippi
Authors: Jackson Stephen T. , Givens Charles R.
Published: October 2002

Pollen, plant macrofossil, and radiocarbon-dating studies of seven exposures of fluvial sediments in the Tunica Hills region of southeastern Louisiana and southwestern Mississippi provide new information on late Wisconsinan vegetation, flora, and environment of the region. The assemblages date between 25,250 and 17,530 yr B.P. Pollen and macrofossil assemblages are dominated byPicea,which comprises 40-70% of the pollen assemblages.AbiesandLarixpollen and macrofossils are absent, in contrast to sites to the north in the central Mississippi Valley. Deciduous hardwoods (Quercus, Fagus, Fraxinus, Carya, Juglans nigra, Acer, Ulmus) are minor components of both pollen and macrofossil assemblages. Radiocarbon dates ofPiceaandQuercuswood indicate that these two genera grew contemporaneously in the region. Regional upland forests were dominated byPicea. Piceacones and cone fragments are not typical of any extant North American species, and probably represent either an extinct species or an extinct variety or subspecies ofPicea glauca.Late Wisconsinan climate of the region was cooler than present, but not necessarily as cool as implied byP. glaucaor other "boreal" taxa.
The Potential Role of Peatland Dynamics in Ice-Age Initiation
Authors: Klinger Lee F. , Taylor John A. , Franzen Lars G.
Published: October 2002

Physical and chemical coupling of peatland vegetation, soils and landforms, and atmosphere creates feedbacks which may be important in ice-age initiation. A box diffusion CO2 exchange model shows that a transient forcing of 500 Gt C (the amount proposed to have accumulated in peatlands during the last interglacial–glacial transition) over 5000 yr results in a lowering of atmospheric CO2 by about 40 ppm. Proxy data indicate that a decrease in atmospheric CO2 may have occurred over the last 5000 yr up to preindustrial times, and the amount is similar to that calculated from Holocene peatland expansion (∼22 ppm). These results suggest that models should consider the role of peatlands in ice-age initiation.
Sea Surface Temperature Changes in the Northeastern Pacific Ocean during the Past 20,000 Years and Their Relationship to Climate Change in Northwestern North America
Authors: Sabin Ann L. , Pisias Nicklas G.
Published: October 2002

Modern ocean–atmosphere interactions in the northeastern Pacific Ocean have a significant effect on the climate of the west coast of North America. We present radiolarian microfossil-based temperature reconstructions for the eastern North Pacific spanning the past 20,000 yr to examine possible correlations and linkages between continental climate change and changes in sea surface temperature (SST) in the northeastern Pacific Ocean on millennial time scales. The reconstructions indicate that the regional pattern of ocean circulation off the west coast of North America was further south 15,000 cal yr B.P. than it is today, and reached its present location 13,000 cal yr B.P. The North Pacific Drift and Transition Zone were further south as a result of a more southerly North Pacific high pressure cell prior to 13,000 cal yr B.P. While two continental paleoclimate records from northwestern North America show regional differences, they also can be correlated to the SST changes. A coastal site at 48°N shows similar patterns in summer temperatures, as observed in offshore marine records of SSTs. However, an inland continental record seems to reflect more-regional-scale changes in sea surface conditions showing a thermal maximum centered at 10,000 cal yr B.P which is observed in the marine transect south of 42°N. We conclude, based on the pattern of oceanographic change as reflected in radiolarian assemblages, that changes in the past latitudinal position of the North Pacific Drift played a significant role in controlling continental climate immediately to its east, as it does in the present environment. We also conclude that during the past 20,000 yr much of the evolution of oceanographic change is related to the migration of the atmospheric pressure cells (the North Pacific high and Aleutian low) of the northeastern Pacific.
Comparison and Contrast of Processes of Soil Formation in the San Timoteo Badlands with Chronosequences in California
Authors: Kendrick Katherine J. , McFadden Leslie D.
Published: October 2002

The degree of soil development associated with geomorphic surfaces in the San Timoteo Badlands area (STB), California allows correlation of the surfaces. Soil development indices, based on field descriptions and laboratory analysis, provide a basis for comparison of these soils to each other and to dated soil chronosequences at Cajon Pass, Merced, and Anza, California. The soils in this study record a complex tectonic and climatic history, include preserved surfaces intermediate in soil development to those at Cajon Pass, and do not preserve a record of the major late Pleistocene to early Holocene aggradational event observed elsewhere in the region. Pedogenesis is similar to that of regional soils in southern California. With time, the profiles develop progressively thicker argillic horizons, and they increase in redness, clay, and secondary iron oxide content, and amount and thickness of clay films. With increasing soil age the ratio of dithionite-extractable Fe to total Fe increases, while the ratios of Fe2+to Fe3+and of oxalate- to dithionite-extractable Fe decrease. These trends are more subdued in the STB than elsewhere in the region, perhaps because the slightly higher temperature and lower precipitation of the STB may slow the rate of transformation of ferrihydrite to hematite. We use weighted means of soil development indices and rubification index values to compare the soils of this study to those at Cajon Pass, Merced, and Anza. Wide-range age estimates using the maximum limits of these values result in 27,500–305,000 yr for surface Q1, 43,000–570,000 yr for surface Q2, and 300,000–700,000 yr for surfaces Q3 and Q4. Weighing most heavily the nearest dated chronosequences, Anza and Cajon Pass, yields best estimates of age. This method constrains the time of formation of the Q1 surface to between 27,500 and 67,000 yr and the Q2 surface to 43,000–67,000 yr, and does not change the age estimates of the older surfaces.
Palynological Evidence for Late- and Postglacial Environmental Change in Central Colorado
Authors: Vierling Lee A.
Published: October 2002

A sediment core recovered from Lost Park (39°17′30″N, 105°32′30″W; elevation 3079 m) provides palynological evidence for postglacial vegetational and environmental change in the central Front Range of Colorado. Pine–spruce woodland was the dominant vegetation type throughout the ∼12,000-yr-long record. Nonarboreal taxa, however, showed substantial changes. From 11,800 to 9100 14C yr B.P., high Artemisia levels suggest steppe vegetation indicative of a climate cooler than that at present with an annual precipitation regime dominated by winter moisture. The pollen spectra of this interval resemble modern spectra at two sites within Colorado and Wyoming; comparisons of modern climatic data suggest that Lost Park may have experienced winter temperatures 3° to 3.5°C colder than those at present and monthly winter precipitation levels 3.5 cm higher than those at present during this late-glacial time. Lower Artemisia, coupled with increases in Poaceae pollen, suggest a shift to warmer conditions dominated by summer (monsoon) precipitation around 9100 14C yr B.P. Increased charcoal occurrences between ∼6000 and ∼4000 14C yr B.P. may suggest the onset of drier summer conditions that would be expected with a waning summer monsoon circulation at that time. Since 180014C yr B.P., a resurgence in Artemisia pollen suggests a return to relatively cool and/or dry conditions similar to the present climate.
Geochemical Characterization of Late Pleistocene and Holocene Tephra Layers from the Basin of Mexico, Central Mexico
Authors: Ortega-Guerrero Beatriz , Newton Anthony J.
Published: October 2002

In order to aid palaeoenvironmental research of Late Pleistocene and Holocene deposits of central Mexico, tephra layers collected from the sediments of the Texcoco and Chalco sub-basins, in the southern part of the Basin of Mexico, are geochemically characterized and used as stratigraphic markers. The tephra layers range in composition from basaltic andesites to rhyolites and are calc-alkaline. The tephras range in age from >34,000 to ca. 260014C yr B.P. New names are used informally to designate correlated tephras. The Tlahuac tephra is present in Chalco, at a depth of 18 m; in the southeastern part of Texcoco, at a depth of around 10 m; and at the Tlapacoya archaeological site, where it had been mistakenly described as basaltic. This basalt–andesite tephra is dated to at least 34,00014C yr B.P. The Tlapacoya 1 tephra is dated to between 15,020 ± 450 and 14,430 ± 190 yr B.P. and is present in all Chalco sections. The Tlapacoya 2 tephra corresponds to the previously described “pomez gruesa con fragmentos de andesita” (ca. 14,400 yr B.P.) and is present in all Chalco and Texcoco sections. The likely source of these three tephras is the volcano Popocatepetl. Tephra II at Chalco dates to 12,520 ± 135 yr B.P. and correlates with the Upper Toluca Pumice from Nevado de Toluca volcano. These represent the first geochemical glass-shard analysis of tephras from the Basin of Mexico, and so further research is necessary before a reliable tephrochronology can be established.
A system for the heterologous expression of complex redox proteins in Rhodobacter capsulatus: characterisation of recombinant sulphite:cytochrome c oxidoreductase from Starkeya novella
Authors: Kappler Ulrike , McEwan Alastair G.
Published: October 2002

The phototrophic purple non‐sulfur bacterium Rhodobacter capsulatus expresses a wide variety of complex redox proteins in response to changing environmental conditions. Here we report the construction and evaluation of an expression system for recombinant proteins in that organism which makes use of the dor promoter from the same organism. A generic expression vector, pDorEX, was constructed and used to express sulphite:cytochrome c oxidoreductase from Starkeya novella, a heterodimeric protein containing both molybdenum and haem c. The recombinant protein was secreted to the periplasm and its biochemical properties were very similar to those of the native enzyme. The pDorEX system therefore seems to be potentially useful for heterologous expression of multi‐subunit proteins containing complex redox cofactors.
The activation of nuclear phosphoinositide 3‐kinase C2β in all‐trans‐retinoic acid‐differentiated HL‐60 cells
Authors: Višnjić Dora , Crljen Vladiana , Ćurić Josip , Batinić Drago , Volinia Stefano , Banfić Hrvoje
Published: October 2002

The activity of nuclear phosphoinositide 3‐kinase C2β (PI3K‐C2β) was investigated in HL‐60 cells induced to differentiate along granulocytic or monocytic lineages. A significant increase in the activity of immunoprecipitated PI3K‐C2β was observed in the nuclei and nuclear envelopes isolated from all‐trans‐retinoic acid (ATRA)‐differentiated cells which was inhibited by the presence of PI3K inhibitor LY 294002. High‐performance liquid chromatography analysis of inositol lipids showed an increased incorporation of radiolabelled phosphate in both PtdIns(3)P and PtdIns(3,4,5)P3 with no changes in the levels of PtdIns(4)P, PtdIns(3,4)P2 and PtdIns(4,5)P2. Western blot analysis of the PI3K‐C2β immunoprecipitates with anti‐P‐Tyr antibody revealed a significant increase in the level of the immunoreactive band corresponding to PI3K‐C2β in the nuclei and nuclear envelopes isolated from ATRA‐differentiated cells.
Recombinant Escherichia coli biotin synthase is a [2Fe–2S]2+ protein in whole cells
Authors: Cosper Michele Mader , Jameson Guy N.L , Eidsness Marly K , Huynh Boi Hanh , Johnson Michael K
Published: October 2002

EPR and Mössbauer spectroscopies have been used to determine the type and properties of the iron–sulfur clusters present in homologously expressed recombinant Escherichia coli BioB in whole cells prior to purification. Difference EPR spectra of samples of whole cells from a strain over‐expressing E. coli BioB and a strain containing the same plasmid but without the bioB insertion showed an axial S=1/2 resonance that was attributed to the [2Fe–2S]+ cluster of the E. coli iron–sulfur cluster assembly 2Fe ferredoxin, based on principal g‐values, linewidths and relaxation behavior. Comparison of the Mössbauer spectra of whole cells with and without the bioB insertion revealed that the E. coli cells with over‐expressed BioB contain an additional species that exhibits a spectrum identical to that of the [2Fe–2S]2+ cluster in purified recombinant BioB. The concentration of this [2Fe–2S]2+ species in the whole cell sample was quantified using a Mössbauer standard and found to be approximately 260 μM, which was comparable to the BioB protein concentration estimated for the cell paste. The results demonstrate that the [2Fe–2S]2+ cluster found in purified samples of recombinant BioB is not an artifact of the protein purification procedure, and indicate that recombinant BioB is over‐expressed in an inactive form during aerobic growth.
The impact of social‐responsibility screens on investment performance: Evidence from the Domini 400 social index and Domini Equity Mutual Fund
Authors: Sauer David A.
Published: October 2002

Socially responsible investors apply both financial and social criteria when evaluating investments in order to ensure that the securities selected are consistent with their personal value system and beliefs. This paper examines the potential impact these additional restrictions have on investment performance by comparing the performance characteristics of a carefully constructed, well diversified portfolio of socially screened stocks with two unrestricted benchmark portfolios. In contrast to prior research, the performance of the socially responsible portfolio examined in this paper is not subject to the confounding effects of trans‐ action costs, management fees, or differences in investment policy that are associated with actively managed mutual funds. Therefore, it is possible to more clearly isolate the potential performance implications associated with subjecting the investment opportunity set to social screening. Contrary to expectations, our findings indicate that application of social‐responsibility screens does not necessarily have an adverse impact on investment performance.
Prospect theory as an explanation of risky choice by professional investors: Some evidence
Authors: Olsen Robert A.
Published: October 2002

This paper examines the results of surveys of professional investment managers' risk perceptions and investment preferences. Managers are found to exhibit loss aversion, to be risk averse for gains and risk loving for loss; and to believe in time diversification. The results are consistent with the implications of the S‐shaped value function of Prospect Theory.
Effects of dietary supplements of algae, containing polyunsaturated fatty acids, on milk yield and the composition of milk products in dairy ewes
Authors: PAPADOPOULOS GEORGE , GOULAS CHRISTOS , APOSTOLAKI ELENI , ABRIL RUBEN
Published: October 2002

Thirty-two lactating Karagouniko ewes were allocated at random to four groups for 6 weeks, to examine the effect of four diets: C (control treatment, ration without algae); LA (ration with low level of algae); MA (ration with medium level of algae) and HA (ration with high level of algae); containing 0, 23·5, 47 and 94 g algae, respectively, on the enrichment of milk and dairy products. Addition of algae reduced (P<0·001) DM intake for treatments MA and HA. Milk yield did not differ between treatments but milk composition was significantly affected by dietary inclusion of algae. Milk fat content was significantly increased (P<0·001) for treatment HA whereas milk protein content was significantly increased (P<0·001) for all treatments containing algae. Milk from treatments LA, MA and HA was significantly enriched in the following PUFA: C20[ratio ]5 (n-3) (0·4–2·1%), C22[ratio ]5 (n-6) (0·8–4·1%), C22[ratio ]6 (n-3) (4·3–12·4%) (P<0·001) and C22[ratio ]5 (n-3) (2·1–3·1%) (P<0·05), which were not detected in control milk. Feta cheese and yogurts produced from the enriched milk had identical composition with the milk, and would be characterized as healthy foods. The ratio of n-6 to n-3 fatty acids was 2·5–4·5.
A preliminary analysis of the structure of benthic assemblages of surf zones on two morphodynamic types of beach
Authors: Barros F. , Underwood A.J. , Lindegarth M.
Published: October 2002

Predictions that there should be more benthic invertebrates and greater diversity in deeper areas and differences in the spatial structure of assemblages on different types of beaches were tested on two Reflective and two Intermediate (Transverse Bar and Rip) sandy beaches around Sydney, New South Wales, Australia. The macrofaunal assemblages of surf zones were more diverse and there were more invertebrates on Reflective than TBR beaches, and there was an increase in number of invertebrates and, significantly, in diversity from 1·5 to 2·5 m depths. There was significant variation in the structure of assemblages among beaches of the same type. Spatial variability in the structure of assemblages on Intermediate beaches was greater than on Reflective beaches. Macrofaunal assemblages varied significantly at a scale of tens of metres across shore, particularly on Reflective beaches.
The distribution of Ceratothoa steindachneri (Crustacea: Isopoda: Cymothoidae) parasitic in Echiichthys vipera in the north-east Atlantic
Authors: Horton Tammy , Okamura Beth
Published: October 2002

The distribution of the recently discovered association of the parasitic isopod Ceratothoa steindachneri (Isopoda: Cymothoidae) with the lesser weever fish (Echiichthys vipera) is reported. Ceratothoa steindachneri appears to have colonized the south-west coast of the UK between the 1960s and the 1980s, possibly as a result of range expansion due to climate change. The occurrence of C. steindachneri in E. vipera from Arcachon, France, indicates that this association has been occurring for over 100 years. Our data confirm that C. steindachneri is able to parasitize a broad range of fish hosts.
Reproductive cycle of Bolinus brandaris and penis and genital duct size variations in a population affected by imposex
Authors: Ramón Montserrat , Amor María José
Published: October 2002

The reproductive cycle of Bolinus brandaris (Gastropoda: Muricidae) was investigated.
Specimens were sampled monthly from a site off Sant Carles de la Ràpita, in the western
Mediterranean, between February 1999 and March 2000. A pattern was observed in the reproductive
cycle, with two reproductive peaks (April and June–July).
The first stages of gametogenesis began in September for males and November for
females. Mature males were found from December to April and from June to July.
Maximum ripening in females was attained at the end of June and during July,
coinciding with the spawning season. In May, there was a resting stage in females,
and for both sexes from August to October.

Males exhibited variation in penis length and vas deferens width related to the reproductive cycle. Sizes of both dimensions increased as maturation progressed. The variation was not found in imposex females.
Predation of guanacos (Lama guanicoe) by southernmost mountain lions (Puma concolor) during a historically severe winter in Torres del Paine National Park, Chile
Authors: Bank Michael S. , Sarno Ronald J. , Campbell Nichole K. , Franklin William L.
Published: October 2002

The effects of mountain lion Puma concolor predation on guanaco Lama guanicoe mortality was investigated during the historically severe winter of 1995 in Torres del Paine National Park, Chile. The 45 guanaco carcasses located represented 3% of the entire guanaco population of which 74% were mountain lion kills, 13% died from malnutrition, 2% died from fence entanglement and 11% died from unknown causes. Depleted bone marrow fat was observed in 20% of all carcasses. The number of guanaco deaths differed among sex and age classes, particularly in juveniles (< 1 year of age), which died more often than expected (P < 0.001). Fresh guanaco carcasses (n= 19) killed by mountain lions were located in tree and shrub habitats 79% of the time and were significantly greater than expected values based on the relative availability of these habitats (P < 0.001). Observations of the spatial distribution of mountain lion kills and guanaco mixed‐sex groups were similar (P= 0.10), suggesting that mountain lions responded to winter migratory movements made by guanacos. Overall, adult guanacos experienced surprisingly lower levels of mortality (adult male = 1%, adult female = 2%) than expected, despite the severe winter conditions, while juveniles experienced higher levels of mortality (13%) than expected. In comparison to other years (1991–96), the severe winter of 1995 (i.e. this investigation) had the greatest total mortality for juveniles, although the proportion of deaths caused by mountain lion predation for juveniles was greatest during other winters.
Home‐range use by white‐nosed coatis (Nasua narica): limited water and a test of the resource dispersion hypothesis
Authors: Valenzuela D. , Macdonald D. W.
Published: October 2002

The resource dispersion hypothesis (RDH) proposes that in a spatially and temporally heterogeneous environment the territory size of social carnivores increases as the dispersion of limited resources is more widely spaced, whereas group size is limited, independently, by the richness or abundance of those resources or key habitats. To assess if white‐nosed coatis Nasua narica behave in accordance with the RDH, the relationship between home‐range size and spatio‐temporal availability of resources in Mexican tropical dry forests with marked seasonal rainfall was examined. Specifically, home‐range sizes were compared at two study sites that were broadly similar but contrasting in resource abundance and dispersion. Home‐range estimates for seven white‐nosed coati bands varied between 45 and 362 ha. Home‐range size did not correlate with food resource abundance and was better explained by the dispersion of water sources during the dry season. Average home‐range size was three times greater at the site where water sources were more widely separated during the dry season. These results are in accordance with the predictions of the RDH, and provide an example where the critical resource determining range size and configuration is water.
Glow discharge with diminishing neutral plasma
Authors: Demokan O. , Akman S.
Published: October 2002

In this work, the anode–cathode distance in a direct current glow discharge is reduced manually to values smaller than the Child–Langmuir extent, while the discharge current, the discharge voltage and the Langmuir probe current are monitored continuously. The discharge current is observed to develop a large peak as soon as the sheath edge contacts with the anode, then decays to negligible values for a certain time interval, after which, this cycle starts repeating itself periodically. A model is described to interpret the behavior of all three quantities self-consistently. The experiment is performed with different anode–cathode distances and the implications of the observations regarding ion implantation processes are discussed.
Millimeter-wave spectroscopy of the internal-rotation band of the He–HCN complex and the intermolecular potential energy surface
Authors: Harada Kensuke , Tanaka Keiichi , Tanaka Takehiko , Nanbu Shinkoh , Aoyagi Mutsumi
Published: October 2002

Millimeter-wave absorption spectroscopy combined with a pulsed-jet expansion technique was applied to measure the internal-rotation band of He–HCN in the frequency region of 95–125 GHz. In total 13 rovibrational lines, split into nitrogen nuclear hyperfine structure, were observed for the fundamental internal-rotation band, j=1−0. The observed transition frequencies were analyzed including their hyperfine splitting to yield an intermolecular potential energy surface, as improved from the one given by a coupled-cluster single double (triple) ab initio calculation. The surface obtained has a global minimum in the linear configuration (He⋅⋅⋅H–C–N) with a well depth of 30.2 cm−1, and a saddle point located in the antilinear configuration (H–C–N⋅⋅⋅He) which is higher by 8.91 cm−1 in energy than the global minimum. The distance Rm between the He atom and the center of mass of HCN along the minimum energy path shows a strong angular dependence; Rm is 4.169 and 4.040 Å in the linear and antilinear forms, respectively, while it is 3.528 Å in a T-shaped configuration. In the first excited internal-rotation state (j=1), levels with l less than 4 are bound but not for the one with l = 5, according to the energy level diagram calculated from the present potential energy surface, where l denotes the quantum number for the end-over-end rotation of the complex. The energy level diagram is consistent with the millimeter-wave observation, in which the Δl=0 transitions with l=0∼4 were observed but not for those with l equal to or greater than 5. The band origin of the internal-rotation band, 98.70 GHz, as defined to be the same as the frequency of the R(0) transition, is larger by 11% than the J=1−0 rotational transition frequency of the free HCN molecule.
A density functional theory study of phosphorescence and triplet–triplet absorption for nonlinear absorption chromophores
Authors: Nguyen Kiet A. , Kennel Josh , Pachter Ruth
Published: October 2002

We report a systematic study of the nonlinear absorption characteristics of π-conjugated chromophores using density functional theory (DFT), namely, the prediction of singlet–triplet splittings (S0–T1), vertical triplet–triplet (T1–Tn) excitation energies, and corresponding oscillator strengths. This is a first application of DFT/time-dependent DFT to a broad range of π-conjugated test molecules for the prediction of the T1–Tn excitation energies and oscillator strengths and the S0–T1 energies, using Becke’s three-parameter hybrid functional. Our results show a good agreement with experimental excitation energies and oscillator strengths. The range of errors obtained from the computed results is discussed in detail.
Characterization of silicon micro-oscillators by scanning laser vibrometry
Authors: Vignola J. F. , Liu X. , Morse S. F. , Houston B. H. , Bucaro J. A. , Marcus M. H. , Photiadis D. M. , Sekaric L.
Published: October 2002

The dynamics of single-crystal silicon ∼100 μm size rectangular paddle oscillators at room temperature have been studied using a recently developed high-resolution scanning laser vibrometer. The dynamic mechanical behavior is determined by scans of the entire device, providing both amplitude and phase spatial maps of the vibratory response. These reveal more than 16 normal modes below 500 kHz. In addition to simple translation and torsional motion, flexural modes of the paddle plate are observed. Quality factors ranging from 1×103 to 2×104 are measured and are found to be significantly lower than those expected from well-known intrinsic absorption mechanisms. The measurements reveal that there exists significant modification of the expected eigenfrequencies and mode shapes. It is speculated that this is caused by excessive undercutting of the support structure, and that the resulting energy flow into the support leads to increased oscillator loss. Indeed, some correlation is found between observed loss and energy levels resident in the supports. At frequencies where there is relatively little support motion, three-dimensional finite-element modeling accurately predicts the paddle modal behavior.
Current density in exchange-correlation functionals: Application to atomic states
Authors: Becke Axel D.
Published: October 2002

An old and yet unsolved problem in density-functional theory is the strong dependence of degenerate open-shell atomic energies on the occupancy of the atomic orbitals. This arises from the fact that degenerate atomic orbitals of different ml do not have equivalent densities. Approximate density functionals therefore give energies depending strongly on which orbitals are occupied. This problem is solved in the present work by incorporating current density into the calculations using a current-density dependent functional previously published by the author.
Semiclassical calculation of collisional dissociation cross sections for N+N2
Authors: Tully Catherine , Johnson Robert E.
Published: October 2002

Dissociation and doubly differential cross sections are calculated for N+N2 at near-threshold collision energies using a semiclassical wave packet method in which the vibrational motion of the molecule is treated quantum mechanically and the rotational and translational motions are treated classically. A three-bodied London–Eyring–Polanyi–Sato potential energy surface is used and results compared to those obtained using a purely repulsive power law potential. For a comparison of results, cross sections are also calculated using pure classical mechanics.
The aging of tungsten filaments and its effect on wire surface kinetics in hot-wire chemical vapor deposition
Authors: Holt Jason K. , Swiatek Maribeth , Goodwin David G. , Atwater Harry A.
Published: October 2002

Wire-desorbed radicals present during hot-wire chemical vapor deposition growth have been measured by quadrupole mass spectrometry. New wires produce Si as the predominant radical for temperatures above 1500 K, with a minor contribution from SiH3, consistent with previous measurements; the activation energy for the SiH3 signal suggests its formation is catalyzed. Aged wires also produce Si as the predominant radical (above 2100 K), but show profoundly different radical desorption kinetics. In particular, the Si signal exhibits a high temperature activation energy consistent with evaporation from liquid silicon. The relative abundance of the other SiHx species suggests that heterogeneous pyrolysis of SiH4 on the wire may be occurring to some extent. Chemical analysis of aged wires by Auger electron spectroscopy suggests that the aging process is related to the formation of a silicide at the surface, with silicon surface concentrations as high as 15 at. %. A limited amount (2 at. %) of silicon is observed in the interior as well, suggesting that diffusion into the wire occurs. Calculation of the relative rates for the various wire kinetic processes, coupled with experimental observations, reveals that silicon diffusion through the silicide is the slowest process, followed by Si evaporation, with SiH4 decomposition being the fastest.
Wrinkled polypyrrole electrode for electroactive polymer actuators
Authors: Watanabe Masashi , Shirai Hirofusa , Hirai Toshihiro
Published: October 2002

As an electrode for a bending-electrostrictive polyurethane actuator, we prepared a wrinkled polypyrrole electrode, expecting the following two effects because the wrinkled electrode could easily elongate by smoothing the wrinkles: (1) conductivity of the electrode would not decrease with the field-induced surface elongation of the actuator, and (2) the electrode would not constrain the actuation. The wrinkled electrode was prepared through in situ deposition of polypyrrole onto the polyurethane elastomer film that was being uniaxially drawn. After the deposition, the film was released from the drawing to make the electrode wrinkle. The conductivity of the wrinkled electrode did not decrease at elongation rates less than 40%. The bending actuation of the polyurethane film with the wrinkled electrode was improved more than twice that as compared with an unwrinkled one. In addition, doping the polyurethane with sodium acetate also improved the actuation. By these improvements, the bending actuation reached 7 mm in radius of curvature within 0.2 s when the applied voltage was 1000 V.