bluuebunny/crossref_metadata_2025_split huggingface dataset:
Environmental and vegetation variables have a greater influence than habitat fragmentation in structuring lizard communities in remnant urban bushland
Authors: JELLINEK S. , DRISCOLL D. A. , KIRKPATRICK J. B. 
Published: May 2004

Abstract  The expansion of urban areas and adjacent farming land into natural landscapes modifies habitats and produces small isolated pockets of native vegetation. This fragmentation of the natural habitat subdivides animal communities, reduces population sizes and increases vulnerability to extinction. In this paper we investigate whether fragmentation decreases lizard species richness, composition, overall abundance and abundance at the species level. Urban remnants consisting of five small (< 10 ha) and four large (> 10 ha) fragments of natural bushland were paired with continuous bushland areas located near Hobart, Tasmania, Australia. These remnants were surveyed six times, using pitfall traps, from November 2001 to March 2002. Lizard species richness and abundance were not significantly influenced by habitat fragmentation or fragment size. Egernia whitii was the only lizard species significantly influenced by fragment size, and was only present in large fragments and continuous bush. Vegetation type and structure as well as environmental variables (geology and aspect) influenced the structure of reptile communities. Lizard species that were able to use a number of different habitat types were found to persist at most sites, irrespective of fragment size. Edge environment did not significantly influence lizard species richness or abundance in remnant areas. Lizard species richness was significantly lower in sites that had a high ratio of exotic to native plant species. Therefore, if remnants continue to be invaded by exotic plants, lizard species that require native plant communities will become increasingly vulnerable to local extinction. Our results suggest that lizard species requiring specialized habitats, such as E. whitii, may persist in large urban remnants rather than small urban remnants because large reserves are more likely to encompass rare habitats, such as rocky outcrops. Habitat heterogeneity, rather than size, may be the key to their persistence.
Distribution of plant‐dwelling spiders: Inflorescences versus vegetative branches
Authors: SOUZA ANDRÉA LÚCIA TEIXEIRA DE , MARTINS ROGÉRIO PARENTONI 
Published: May 2004

Abstract  The influence of the architecture of vegetative branches on the distribution of plant‐dwelling spiders has been intensively studied, and the effects on the aggregation of individuals in several spider species on plants include variation in prey abundance, availability of predator‐free refuges and smoother microclimate conditions. The emergence of inflorescences at the reproductive time of the plants changes branch architecture, and could provide higher prey abundance for the spiders. The distribution of spiders between inflorescences and vegetative branches was compared on four widespread plant species in a Brazilian savannah‐like system. Inflorescences attracted more spiders than vegetative branches for all plant species sampled. The influence of branch type (inflorescence and vegetative) on spider distribution was also evaluated by monitoring branches of Baccharis dracunculifolia DC. in vegetative and flowering periods for 1 year, and through a field experiment carried out during the same period where artificial inflorescences were available for spider colonization. Artificial inflorescences attached to B. dracunculifolia branches attracted more spiders than non‐manipulated vegetative branches for most of the year. However, this pattern differed among spider guilds. Foliage‐runners and stalkers occurred preferentially on artificial inflorescences relative to control branches. The frequencies of ambushers and web‐builders were not significantly different between treatment and control branches. However, most ambush spiders (65%) occurred only during the flowering period of B. dracunculifolia, suggesting that this guild was influenced only by natural inflorescences. The experimental treatment also influenced the size distribution of spiders: larger spiders were more abundant on artificial inflorescences than on vegetative branches. The hypothesis that habitat architecture can influence the spider assemblage was supported. In addition, our observational and experimental data strongly suggest that inflorescences can be a higher quality microhabitat than non‐reproductive branches for most plant‐dwelling spiders.
Variations in the configuration of algae in subtidal forests: Implications for invertebrate assemblages
Authors: GOODSELL P. J. , FOWLER‐WALKER M. J. , GILLANDERS B. M. , CONNELL S. D. 
Published: May 2004

Abstract  The ecology of Australia's most extensive canopy‐forming alga, Ecklonia radiata, is often studied with little regard as to whether it occurs in monospecific stands or as part of a mixed assemblage of canopy‐forming algae. We tested the hypothesis that E. radiata does not primarily occur as monospecific stands, rather it occurs more often in stands of mixed algae. At a 1‐m2 scale we recognized three main configurations within forests of algae (hereafter called stands): E. radiata that occurs as (i) monospecific stands; (ii) clumps (four or more individuals together) surrounded by species of Fucales; or (iii) individual plants (or clusters of fewer than three plants) interspersed among species of Fucales. All three types of stand occurred in similar proportions (percentage cover) across two regions of Australia's southern coastline (Western and South Australia). We also tested the hypothesis that these three types of stands (identified at 1 m2) contain different assemblages of invertebrates associated with the holdfast of E. radiata. Assemblages of invertebrates varied between monospecific and interspersed stands, but not between monospecific and clumped stands. These results suggest that variation in the configuration of subtidal algae (stands measured at a 1‐m2 scale) has the potential to influence the composition and abundance of associated biota. We suggest that although studies in stands of monospecific E. radiata may provide useful information for the majority of forests containing E. radiata (monospecific and clumped stands made up 65% of forests sampled), caution must be used when extrapolating to stands of mixed, interspersed algae (>31% of forests sampled).
Delayed gastric emptying in the obese: an assessment using the non‐invasive 13C‐octanoic acid breath test
Authors: Jackson S. J. , Leahy F. E. , McGowan A. A. , Bluck L. J. C. , Coward W. A. , Jebb S. A. 
Published: May 2004

Aim:  Much of the controversy surrounding the correlation between obesity and gastric emptying lies in the inconsistency of methodology and analysis. This study was designed to overcome some of the discrepancies encountered in previous studies and to test the hypothesis that obese individuals have altered gastric emptying compared to lean individuals.Methods:  Gastric emptying was measured using the 13C‐octanoic acid breath test in 16 lean and 16 obese women pair‐matched for age. Following an overnight fast, subjects were given a standard 2 MJ egg meal labelled with 100 µl of [1‐13C]‐octanoic acid. Breath samples were collected at regular intervals over a 6‐h period. 13C‐isotopic enrichment in the breath was analysed using isotope ratio mass spectrometry and the data fitted to the established gastric emptying model. The lag times (tlag), half excretion times (t1/2), latency phase (tlat) and ascension times (tasc) were calculated.Results:  The mean t1/2‐values (±standard error of the mean) were 3.67 ± 0.14 h and 4.23 ± 0.18 h for lean and obese respectively, indicating significantly delayed gastric emptying in the obese (p = 0.019). The obese group also showed a significantly slower lag time (tlag, p = 0.005) and latency phase (tlat, p = 0.005), but no significant difference was found in the ascension time (tasc, p = 0.154). Within groups, no correlation was found between half excretion times and body weight or half excretion times and body mass index.Conclusions:  The present study demonstrated a prolonged lag phase and delayed gastric emptying in obese women when compared to lean women. This delay may be as a consequence of high‐fat diets, a sedentary lifestyle and increased gastric distension associated with obesity, or a contributing factor in the pathogenesis of obesity resulting from the inactivation of gastrointestinal satiety signals and in an increase in food intake.
Thiazolidinedione therapy in the prevention/delay of type 2 diabetes in patients with impaired glucose tolerance and insulin resistance
Authors: Durbin R. J. 
Published: May 2004

Aim:  The second‐generation thiazolidinediones (TZDs), rosiglitazone and pioglitazone, significantly decrease fasting plasma glucose and glycosylated haemoglobin (HbA1c) levels in patients with diabetes. Recent studies suggest that early treatment with TZDs may prevent the progression from insulin resistance (IR) to type 2 diabetes mellitus (T2DM). This prospective analysis examined the effect of early TZD treatment in the prevention or delay of T2DM in a multiethnic population with impaired glucose tolerance (IGT) and IR.Methods:  The analysis included 172 patients (aged 29–86 years) with IGT and IR (normal or borderline HbA1c, C‐peptide levels > 2 mg/ml, fasting blood sugar 100–125 mg/dl, and 2‐h postprandial blood glucose levels 140–200 mg/dl). Patients in the active treatment group (n = 101) had received troglitazone for an average of 10 months before being randomly switched to rosiglitazone (4 mg/day) or pioglitazone (30 mg/day). Patients were switched when troglitazone was withdrawn from the US market because of liver toxicity concerns. Patients with IGT and IR who received no antidiabetic medication served as a control group (n = 71). HbA1c and C‐peptide levels were measured at baseline (2 years) and study end point (3 years). Kaplan–Meier testing, using time to outcome as the main outcome variable, determined risk reduction in the TZD group relative to the control group.Results:  Mean HbA1c and C‐peptide levels decreased for patients receiving either TZD at the 2‐year assessment, and reductions were maintained at study end point. After 2 years, none of the patients receiving TZD therapy progressed to T2DM; three patients progressed to T2DM by study end point. In the control group, 11 patients became diabetic after 2 years and 19 patients became diabetic by the end of the study. The incidence (risk reduction) of diabetes after 3 years was 88.9% lower in the TZD group compared with the control group (p <  0.001).Conclusions:  The TZDs, rosiglitazone and pioglitazone, were effective in reducing HbA1c and C‐peptide levels in patients with IGT/IR. Progression of IR/IGT to T2DM appears to be significantly delayed or prevented with early TZD treatment.
Formulating for efficacy
Authors: Wiechers J. W. , Kelly C. L. , Blease T. G. , Chris Dederen J. 
Published: May 2004

Active ingredients have been around in cosmetics for a long time but have they really resulted in active cosmetic products? In order to achieve this, the right ingredient needs to be delivered to the right location at the right concentration for the correct period of time and the extent (and therefore the concentration) of this delivery depends on the formulation.From a rather theoretical approach based on the polarity of the active ingredient, the stratum corneum and the oil phase, the relative polarity index was established that enables the selection of a suitable emollient for ensuring skin penetration of the active ingredient. Practical examples subsequently show the validity of this approach that demonstrates that one can regulate the delivery of an active molecule (and therefore the efficacy of a cosmetic formulation) by selection and control of the emollient system. Cosmetic formulations are generally quite complex mixtures and subsequent experiments using different emulsifier systems indicated that this component of a cosmetic formulation could also have an impact on steering the active ingredient to the right layer of the skin, although it is too early to be able to derive general rules from this.
Fighting Spam With Statistics
Authors: Goodman Joshua , Heckerman David 
Published: May 2004

Abstract
Spam—unsolicited commercial e-mail—is a complex and growing problem, and threatens to derail the internet revolution. Joshua Goodman and David Heckerman of Microsoft Research describe some statistics-based methods for blocking spam, first by distinguishing it from wanted mail, and then by constructing puzzles they propose to use to challenge suspected spammers.
A Timely Measure of Unemployment
Authors: Thomas Ray 
Published: May 2004

Abstract
Conventional unemployment statistics have two dimensions—size and date. Population-at-risk unemployment rates add a third dimension—time. They are unlikely to revolutionise our picture of the nature of unemployment, says Ray Thomas. But they do give a more accurate and comprehensive picture than existing measures, and provide new insights into old problems, such as indicating the importance of statistics of entrants in helping to explain geographical variation in unemployment.
Requirements for Brome Mosaic Virus Subgenomic RNA Synthesis In Vivo and Replicase-Core Promoter Interactions In Vitro
Authors: Sivakumaran K. , Choi Seung-Kook , Hema Masarapu , Kao C. Cheng 
Published: May 2004

ABSTRACT

Based solely on in vitro results, two contrasting models have been proposed for the recognition of the brome mosaic virus (BMV) subgenomic core promoter by the replicase. The first posits that the replicase recognizes at least four key nucleotides in the core promoter, followed by an induced fit, wherein some of the nucleotides base pair prior to the initiation of RNA synthesis (S. Adkins and C. C. Kao, Virology
252:
1-8, 1998). The second model posits that a short RNA hairpin in the core promoter serves as a landing pad for the replicase and that at least some of the key nucleotides help form a stable hairpin (P. C. J. Haasnoot, F. Brederode, R. C. L. Olsthoorn, and J. Bol, RNA
6:
708-716, 2000; P. C. J. Haasnoot, R. C. L. Olsthoorn, and J. Bol, RNA
8:
110-122, 2002). We used transfected barley protoplasts to examine the recognition of the subgenomic core promoter by the BMV replicase. Key nucleotides required for subgenomic initiation in vitro were found to be important for RNA4 levels in protoplasts. In addition, additional residues not required in vitro and the formation of an RNA hairpin within the core promoter were correlated with wild-type RNA4 levels in cells. Using a template competition assay, the core promoter of ca. 20 nucleotides was found to be sufficient for replicase binding. Mutations of the key residues in the core promoter reduced replicase binding, but deletions that disrupt the predicted base pairing in the proposed stem retained binding at wild-type levels. Together, these results indicate that key nucleotides in the BMV subgenomic core promoter direct replicase recognition but that the formation of a stem-loop is required at a step after binding. Additional functional characterization of the subgenomic core promoter was performed. A portion of the promoter for BMV minus-strand RNA synthesis could substitute for the subgenomic core promoter in transfected cells. The comparable sequence from
Cowpea Chlorotic Mottle Virus
(CCMV) could also substitute for the BMV subgenomic core promoter. However, nucleotides in the CCMV core required for RNA synthesis are not identical to those in BMV, suggesting that the subgenomic core promoter can induce the BMV replicase in interactions needed for subgenomic RNA transcription in vivo.
Resting CD4+T Cells from Human Immunodeficiency Virus Type 1 (HIV-1)-Infected Individuals Carry Integrated HIV-1 Genomes within Actively Transcribed Host Genes
Authors: Han Yefei , Lassen Kara , Monie Daphne , Sedaghat Ahmad R. , Shimoji Shino , Liu Xiao , Pierson Theodore C. , Margolick Joseph B. , Siliciano Robert F. , Siliciano Janet D. 
Published: May 2004

ABSTRACTResting CD4+T-cell populations from human immunodeficiency virus type 1 (HIV-1)-infected individuals include cells with integrated HIV-1 DNA. In individuals showing suppression of viremia during highly active antiretroviral therapy (HAART), resting CD4+T-cell populations do not produce virus without cellular activation. To determine whether the nonproductive nature of the infection in resting CD4+T cells is due to retroviral integration into chromosomal regions that are repressive for transcription, we used inverse PCR to characterize the HIV-1 integration sites in vivo in resting CD4+T cells from patients on HAART. Of 74 integration sites from 16 patients, 93% resided within transcription units, usually within introns. Integration was random with respect to transcriptional orientation relative to the host gene and with respect to position within the host gene. Of integration sites within well-characterized genes, 91% (51 of 56) were in genes that were actively expressed in resting CD4+T cells, as directly demonstrated by reverse transcriptase PCR (RT-PCR). These results predict that HIV-1 sequences may be included in the primary transcripts of host genes as part of rapidly degraded introns. RT-PCR experiments confirmed the presence of HIV-1 sequences within transcripts initiating upstream of the HIV-1 transcription start site. Taken together, these results demonstrate that HIV-1 genomes reside within actively transcribed host genes in resting CD4+T cells in vivo.
Lack of Phenotypic and Functional Impairment in Dendritic Cells from Chimpanzees Chronically Infected with Hepatitis C Virus
Authors: Larsson Marie , Babcock Ethan , Grakoui Arash , Shoukry Naglaa , Lauer Georg , Rice Charles , Walker Christopher , Bhardwaj Nina 
Published: May 2004

ABSTRACTDendritic cells (DCs), which are potent antigen-presenting cells (APCs), are used as adjuvants for the treatment of cancer and infectious diseases in human and nonhuman primates, with documented clinical efficacy. The hepatitis C virus (HCV)-chimpanzee model is the best available model for testing the immunotherapeutic effects of DCs in the setting of a chronic infection, as chimpanzees develop a persistent infection resembling that seen in humans. However, several reports have suggested that DCs derived from chronically infected individuals or nonhuman primates are functionally compromised. As a prelude to clinical studies, we evaluated whether functionally mature DCs could be generated in chimpanzee plasma by good manufacturing practice using CD14+mononuclear precursors from chronically infected chimpanzees. DCs generated in a medium with HCV-negative plasma and treated with a defined cocktail of cytokines or a CD40 ligand trimer matured fully, as measured by the induction of CD83 expression and the upregulation of costimulatory molecules. Furthermore, the expression of CCR7 was induced, suggesting an acquisition of migration capacity. Mature DCs were capable of stimulating allogeneic T cells, antigen-specific memory CD4+T cells, and HCV-specific CD8+-T-cell clones. In all cases, there was no evidence of HCV infection in DCs. Furthermore, these DCs maintained their phenotype and APC function after cryopreservation. Finally, no discernible differences were noted between DCs derived from HCV-infected and uninfected chimpanzees. In summary, precursor cells from HCV-infected chimpanzees are fully capable of differentiating into functional, mature DCs, which can now be reproducibly prepared for investigations of their immunotherapeutic potential in the setting of chronic HCV infection.
Mutational Analysis of the Influenza Virus cRNA Promoter and Identification of Nucleotides Critical for Replication
Authors: Crow Mandy , Deng Tao , Addley Mark , Brownlee George G. 
Published: May 2004

ABSTRACT
Replication of the influenza A virus virion RNA (vRNA) requires the synthesis of full-length cRNA, which in turn is used as a template for the synthesis of more vRNA. A “corkscrew” secondary-structure model of the cRNA promoter has been proposed recently. However the data in support of that model were indirect, since they were derived from measurement, by use of a chloramphenicol acetyltransferase (CAT) reporter in 293T cells, of mRNA levels from a modified cRNA promoter rather than the authentic cRNA promoter found in influenza A viruses. Here we measured steady-state cRNA and vRNA levels from a CAT reporter in 293T cells, directly measuring the replication of the authentic influenza A virus wild-type cRNA promoter. We found that (i) base pairing between the 5′ and 3′ ends and (ii) base pairing in the stems of both the 5′ and 3′ hairpin loops of the cRNA promoter were required for in vivo replication. Moreover, nucleotides in the tetraloop at positions 4, 5, and 7 and nucleotides forming the 2-9 base pair of the 3′ hairpin loop were crucial for promoter activity in vivo. However, the 3′ hairpin loop was not required for polymerase binding in vitro. Overall, our results suggest that the corkscrew secondary-structure model is required for authentic cRNA promoter activity in vivo, although the precise role of the 3′ hairpin loop remains unknown.
RNA Recombination In Vivo in the Absence of Viral Replication
Authors: Gallei Andreas , Pankraz Alexander , Thiel Heinz-Jürgen , Becher Paul 
Published: May 2004

ABSTRACT
To study fundamental aspects of RNA recombination, an in vivo RNA recombination system was established. This system allowed the efficient generation of recombinant cytopathogenic pestiviruses after transfection of synthetic, nonreplicatable, subgenomic transcripts in cells infected with a replicating noncytopathogenic virus. Studies addressing the interplay between RNA recombination and replication revealed that cotransfection of noninfected cells with various pairs of nonreplicatable RNA derivatives also led to the emergence of recombinant viral genomes. Remarkably, homologous and nonhomologous recombination occurred between two overlapping transcripts, each lacking different essential parts of the viral RNA-dependent RNA polymerase (RdRp) gene. Apart from the generally accepted viral replicative copy choice recombination, our results prove the existence of a viral RdRp-independent mechanism of RNA recombination that occurs in vivo. It appears likely that such a mechanism not only contributes to the evolution of RNA viruses but also leads to the generation of recombinant cellular RNAs.