bluuebunny/crossref_metadata_2025_split huggingface dataset:
The hunger to fill an empty space An investigation of primordial affects and meaning‐making in the drive to conceive through repeated use of ART
Authors: Barone‐Chapman Maryann 
Published: August 2007

Abstract:  This research aims to investigate the drive to conceive through repeated use of Assisted Reproductive Technology (ART) in relation to the affective and meaning‐making processes related to this drive, through the use of the participants’ memories of mother and being mothered, the choices they made regarding sex, intimacy and non‐uterine activity in early adulthood and their fantasies of how a child would change their lives.Though prepared for an MSc dissertation it is a pilot empirical study using interpretative phenomenological analysis and applications of Jungian analytic and psychoanalytical theory. The collected data consists of three semi‐structured interviews analysed through recurrent themes and amplification. Developmental and archetypal thinking has been suggested as a means of understanding. The results are strongly suggestive of two main themes across the interviews and further research is underway. The first theme is the importance of the relationship to mother and the quality of the mothering received in contributing to a woman's availability to become a mother at a time in her life when she is most fertile. The second theme of the pilot suggested that the crisis of infertility is a mask for another crisis of identity that also had links to the personal mother. At the core of these issues with mother there is an absence of father and an intra‐psychic couple. Repeated infertility treatment becomes a transformative process necessitating repetition until something new can be created.
Aquatic versus terrestrial locomotion: comparative performance of two ecologically contrasting species of European natricine snakes
Authors: Isaac L. A. , Gregory P. T. 
Published: August 2007

AbstractOne indicator of ecological differences between species is differential locomotory performance in different media. In this study, we compare locomotory speed of two species of natricine snakes on land and in water at a range of temperatures in the laboratory. As expected, both species moved more quickly at higher temperatures and both swam faster than they moved on land. However, the difference between aquatic and terrestrial speed was much greater for the aquatic species, Natrix maura, than for the semi‐aquatic Natrix natrix. Furthermore, although N. maura was significantly faster than N. natrix in water, the opposite was true on land. In fact, N. maura was reluctant to move very far on land at all and would not complete a 2 m terrestrial course. Although we found no evidence of a negative correlation between the aquatic and terrestrial speeds of individual N. natrix, this interspecific comparison is consistent with the notion of a tradeoff between performance abilities on land and in water.
Sperm dumping in a haplogyne spider
Authors: Burger M. 
Published: August 2007

AbstractThe present study shows that females of Silhouettella loricatula (Arachnida: Araneae: Oonopidae) manage to process sperm in an unusual and previously unknown way. The male ejaculate consisting of spermatozoa and globular secretion is enclosed in a secretory sac. This may avoid the mixing of sperm from different males and at least severely limit sperm competition. The process of sperm enclosure occurs within the female's sperm storage site (receptaculum) as the ejaculate is not surrounded by a sac inside the male's sperm‐transferring organs (palpal bulbs). The secretion forming the sac is produced by glands adjoining the receptaculum. The possibility that globular secretions in the male palpal bulbs partly contribute to the sac cannot be ruled out completely. It is suggested that in S. loricatula, the main function of sperm enclosure in a sac is enabling females to dump the ejaculate of a male. The present study represents the first report on sperm dumping in the family Oonopidae. During five first and three second copulations in the laboratory, the dumping of a sac was observed. One dumped sac was sectioned and contained spermatozoa. Two couples were flash‐fixed with liquid nitrogen early during copulation, which revealed the mechanism of the sac dumping. By muscle contractions, the receptaculum is bent backwards and the sac moved into the genital opening. The actual sac dumping occurs most probably in cooperation with the male, which moves his pedipalps rhythmically during the entire copulation. Extensions and furrows on the emboli suggest that they may additionally be used as copulatory courtship devices. The enclosure of sperm from the current male in secretion takes place during or immediately following copulation as all mated females sacrificed after copulation had a new sac containing spermatozoa in the receptaculum. Dumping sperm of a previous male during the next copulation may allow females to bias sperm precedence.
Skeletal and dental growth and development in chimpanzees of the Taï National Park, Côte D'Ivoire
Authors: Zihlman A. L. , Bolter D. R. , Boesch C. 
Published: August 2007

AbstractAn extraordinary collection of 22 immature skeletons from Taï National Park, Côte d'Ivoire, has provided a rare opportunity to establish the timing of dental eruption and its correlation with skeletal fusion and morphometrics in wild chimpanzees of known chronological ages. Comparison of the immature Taï chimpanzeesPan troglodytes veruswith adults from the same population show that sex differences in skeletal maturation apparently appear during the Juvenile II stage, about age 8. A few skeletons from other chimpanzee field sites conform to the dental and skeletal growth in Taï chimpanzees. The tempo of wild chimpanzee growth contrasts sharply with the rate demonstrated for captive individuals. Captive chimpanzees may mature as much as 3 years earlier. The ability to link physical development with field observations of immature chimpanzees increases our understanding of their life‐history stages. These data provide an improved dataset for comparing the rates of growth among chimpanzees,Homo sapiensand fossil hominids.
When east met west: the sub‐fossil footprints of the west European hedgehog and the northern white‐breasted hedgehog during the Late Quaternary in Europe
Authors: Sommer R. S. 
Published: August 2007

AbstractThe distinct distribution of the west European hedgehog Erinaceus europaeus and the northern white‐breasted hedgehog Erinaceus roumanicus and their separate refugial origins after the Pleistocene is a well‐known example in the zoogeography of the Holarctic. Among the Late Quaternary faunal assemblages, the west European hedgehog is recorded at 269 sites whereas the northern white‐breasted hedgehog is recorded only at 52 sites in Europe. The distribution patterns of the temporal and spatial Glacial records of the west European hedgehog show a general trend: a strong restriction to glacial refugia (the Iberian and Italian Peninsulas) during the Weichselian Glacial until the end of the Last Glacial Maximum, and a colonization of southern France during the early Late Glacial between 14 000 and 125 00 14C years BP (15 000–12 800 cal. BC). Whereas the British Isles could have already been colonised by the end of the Pre‐Boreal, in the rest of Central Europe E. europaeus was clearly distributed there in the Boreal for the first time. The west European hedgehog is an absolute Holocene faunal element in Central Europe. It appears in most parts of Central Europe during the Early Holocene, when the west European hedgehog met its eastern relative, which probably was similarly sensitive. After meeting each other, the distribution limit of both Erinaceus species in Central Europe seems to have been relatively constant in its geographic extent. Because of the clear climatic correlation, E. europaeus should be considered as an indicator species for temperate climatic conditions of the Holocene fauna. This should be considered during the reconstruction of climatic conditions with the help of the analysis of quaternary faunal material.
Trafficking and potential assembly patterns of ε‐containing GABAA receptors
Authors: Jones Brian L. , Henderson Leslie P. 
Published: August 2007

AbstractIncorporation of the ε subunit into the GABAA receptor has been suggested to confer unusual, but variable, biophysical and pharmacological characteristics to both recombinant and native receptors. Due to their structural similarity with the γ subunits, ε subunits have been assumed to substitute at the single position of the γ subunit in assembled receptors. However, prior work suggests that functional variability in ε‐containing receptors may reflect alternative sites of incorporation and of not just one, but possibly multiple ε subunits in the pentameric receptor complex. Here we present data indicating that increased expression of ε, in conjunction with α2 and β3 subunits, results in expression of GABAA receptors with correspondingly altered rectification, deactivation and levels of spontaneous openings, but not increased total current density. We also provide data that the ε subunit, like the β3 subunit, can self‐export and data from chimeric receptors suggesting that similarities between the assembly domains of the β3 and the ε subunits may allow the ε subunit to replace the β, as well as the γ, subunit. The substitution of an ε for a β, as well as the γ subunit and formation of receptors with alternative patterns of assembly with respect to ε incorporation may underlie the observed variability in both biophysical and pharmacological properties noted not only in recombinant, but also in native receptors.
TRPV1 expression‐dependent initiation and regulation of filopodia
Authors: Goswami C. , Hucho T. 
Published: August 2007

AbstractTransient receptor potential vanilloid subtype 1 (TRPV1), a non‐selective cation channel, is present endogenously in dorsal root ganglia (DRG) neurons. It is involved in the recognition of various pain producing physical and chemical stimuli. In this work, we demonstrate that expression of TRPV1 induces neurite‐like structures and filopodia and that the expressed protein is localized at the filopodial tips. Exogenous expression of TRPV1 induces filopodia both in DRG neuron‐derived F11 cells and in non‐neuronal cells, such as HeLa and human embryonic kidney (HEK) cells. We find that some of the TRPV1 expression‐induced filopodia contain microtubules and microtubule‐associated components, and establish cell‐to‐cell extensions. Using live cell microscopy, we demonstrate that the filopodia are responsive to TRPV1‐specific ligands. But both, initiation and subsequent cell‐to‐cell extension formation, is independent of TRPV1 channel activity. The N‐terminal intracellular domain of TRPV1 is sufficient for filopodial structure initiation while the C‐terminal cytoplasmic domain is involved in the stabilization of microtubules within these structures. In addition, exogenous expression of TRPV1 results in altered cellular distribution and in enhanced endogenous expression of non‐conventional myosin motors, namely myosin IIA and myosin IIIA. These data indicate a novel role of TRPV1 in the regulation of cellular morphology and cellular contact formation.
A proposed structural basis for picrotoxinin and picrotin binding in the glycine receptor pore
Authors: Yang Zhe , Cromer Brett A. , Harvey Robert J. , Parker Michael W. , Lynch Joseph W. 
Published: August 2007

AbstractPicrotoxin, an antagonist of structurally‐rated GABAA receptors (GABAARs) and glycine receptors (GlyRs), is an equimolar mixture of picrotoxinin (PTXININ) and picrotin (PTN). These compounds share a common structure except that PTN contains a slightly larger dimethylmethanol in place of the PTXININ isopropenyl group. Although the homomeric α1 GlyR is equally sensitive to both compounds, we show here that homomeric α2 and α3 GlyRs, like most GABAARs, are selectively inhibited by PTXININ. As conservative mutations to pore‐lining 6′ threonines equally affect the sensitivity of the α1 GlyR to both compounds, we conclude that PTXININ and PTN bind to 6′ threonines by hydrogen bonding with exocyclic oxygens common to both molecules. In contrast, substitution of the 2′ pore‐lining glycine by serine selectively reduces PTN sensitivity, whereas the introduction of 2′ alanines selectively increases PTXININ sensitivity. These results define the orientation of PTXININ and PTN binding in the α1 GlyR pore and allow us to conclude that the relatively reduced sensitivity of PTN at GABAARs and α2 and α3 GlyRs is due predominantly to its larger size and reduced ability to form hydrophobic interactions with 2′ alanines.
Subtype selective antagonism of substantia nigra pars compacta Group I metabotropic glutamate receptors protects the nigrostriatal system against 6‐hydroxydopamine toxicityin vivo
Authors: Vernon Anthony C. , Zbarsky Virginia , Datla Krishna P. , Croucher Martin J. , Dexter David T. 
Published: August 2007

AbstractEvidence suggests that increased glutamatergic input to the substantia nigra pars compacta as a result of hyperactivity of subthalalmic nucleus output pathways may contribute to the progressive degeneration of nigral dopaminergic neurones in Parkinson’s disease (PD), a debilitating neurodegenerative disorder which affects ∼1% of people aged over 65. Substantial electrophysiological evidence suggests that the excitation of nigral dopaminergic neurones is regulated by the activation of Group I metabotropic glutamate receptors (mGluR), comprising mGluR1 and mGluR5 subtypes. As activation of these receptors by endogenous glutamate may promote multiple cascades leading to excitotoxic neuronal death, it may be hypothesised that functional antagonism of Group I mGluR should be neuroprotective and could form the basis of a novel neuroprotective treatment for PD. To investigate this hypothesis, the neuroprotective potential of the selective competitive mGlu1 antagonist (+)‐2‐methyl‐4‐carboxyphenylglycine ((S)‐(+)‐α‐amino‐4‐carboxy‐2‐methlybenzeneacetic acid; LY367385) and the selective allosteric mGlu5 antagonist 2‐methyl‐6‐(phenylethynyl)‐pyridine (MPEP) was tested in a rodent 6‐hydroxydopamine (6‐OHDA) model of PDin vivo. Both acute and subchronic intranigral administration of either LY367385 or MPEP resulted in significant neuroprotection of nigral tyrosine hydroxylase immunoreactive cell bodies, which correlated closely with prevention of striatal monoamine depletion following 6‐OHDA lesioning. This neuroprotective action of LY367385 and MPEP displayed a clear concentration‐dependent effect, suggesting a receptor‐mediated mechanism of action. LY367385 produced robust neuroprotection at all concentrations tested (40, 200 and 1000 nmol in 4 μL), whilst MPEP displayed a bell‐shaped neuroprotective profile with significant neuroprotection at low concentrations (2 and 10 nmol in 4 μL) but not at higher concentrations (50 nmol). Importantly, subchronic intranigral administration of MPEP and LY367385 appeared to slow the degeneration of remaining nigral dopaminergic neurones and prevented further striatal dopamine depletion in animals with established 6‐OHDA induced nigrostriatal lesions, suggesting that these compounds may significantly influence disease progression in this model.
PERMANENT GENETIC RESOURCES: Isolation of microsatellite loci from the endangered plant Sibara filifolia (Brassicaceae)
Authors: MCGLAUGHLIN MITCHELL E. , WALLACE LISA E. , HELENURM KAIUS 
Published: August 2007

Abstract Sibara filifolia (Brassicaceae) is a federally endangered annual herb found on two of the California Channel Islands. Previous studies based on allozymes revealed little genetic variability on San Clemente Island. Nine polymorphic microsatellite loci were isolated from individuals on San Clemente Island. We found low levels of allelic variation (mean NA = 2.3), with seven loci exhibiting significant deviations from Hardy–Weinberg equilibrium (P < 0.01) and 10 pairs of loci exhibiting significant linkage disequilibrium (P < 0.01). Most of the observed variability (mean HO = 0.003) occurred among populations or in rare homozygous individuals.
Chemical reactivity of microbe and mineral surfaces in hydrous ferric oxide depositing hydrothermal springs
Authors: LALONDE S. V. , AMSKOLD L. , MCDERMOTT T. R. , INSKEEP W. P. , KONHAUSER K. O. 
Published: August 2007

ABSTRACTThe hot springs in Yellowstone National Park, USA, provide concentrated microbial biomass and associated mineral crusts from which surface functional group (FG) concentrations and pKa distributions can be determined. To evaluate the importance of substratum surface reactivity for solute adsorption in a natural setting, samples of iron‐rich sediment were collected from three different springs; two of the springs were acid‐sulfate‐chloride (ASC) in composition, while the third was neutral‐chloride (NC). At one of the ASC springs, mats of Sº‐rich Hydrogenobaculum‐like streamers and green Cyanidia algae were also collected for comparison to the sediment. All samples were then titrated over a pH range of 3–11, and comparisons were made between the overall FG availability and the concentration of solutes bound to the samples under natural conditions. Sediments from ASC springs were composed of hydrous ferric oxides (HFO) that displayed surface FGs typical of synthetic HFO, while sediments from the NC spring were characterized by a lower functional group density, reflected by decreased excess charge over the titration range (i.e., lower surface reactivity). The latter also showed a lower apparent point of zero charge (PZC), likely due the presence of silica (up to 78 wt. %) in association with HFO. Variations in the overall HFO surface charge are manifest in the quantities and types of solutes complexed; the NC sediments bound more cations, while the ASC sediments retained significantly more arsenic, presumably in the form of arsenate (H2AsO4−). When the microbial biomass samples were analyzed, FG concentrations summed over the titratable range were found to be an order of magnitude lower for the Sº‐rich mats, relative to the algal and HFO samples that displayed similar FG concentrations on a dry weight basis. A diffuse‐layer surface complexation model was employed to further illustrate the importance of surface chemical parameters on adsorption reactions in complex natural systems.
Using Spatial Analysis to Study the Values of Variable Rate Technology and Information
Authors: Bullock David S. , Lowenberg‐DeBoer James 
Published: August 2007

AbstractFor adoption of variable rate technology to increase, more knowledge of how crop yields respond to inputs is needed. As the necessary agronomic research involves approximating site‐specific yield response functions, data used inherently lend themselves to spatial analysis. We discuss the different types of spatial analyses that may be appropriate. Then we present a taxonomy for the discussion of the economics of technology and information, and use it to review studies that have contributed significantly to the literature over the past few years. We contend that longer‐term, multilocation agronomic experiments are needed for the estimation of site‐specificex anteoptimal variable input rates, and of expected profitability of variable rate technology and information.
Willingness to Pay for Rural Landscape Improvements: Combining Mixed Logit and Random‐Effects Models
Authors: Campbell Danny 
Published: August 2007

AbstractThis paper reports the findings from a discrete‐choice experiment designed to estimate the economic benefits associated with rural landscape improvements in Ireland. Using a mixed logit model, the panel nature of the dataset is exploited to retrieve willingness‐to‐pay values for every individual in the sample. This departs from customary approaches in which the willingness‐to‐pay estimates are normally expressed as measures of central tendency of an a priori distribution. Random‐effects models for panel data are subsequently used to identify the determinants of the individual‐specific willingness‐to‐pay estimates. In comparison with the standard methods used to incorporate individual‐specific variables into the analysis of discrete‐choice experiments, the analytical approach outlined in this paper is shown to add considerable explanatory power to the welfare estimates.
Segmenting the Wine Market Based on Price: Hedonic Regression when Different Prices mean Different Products
Authors: Costanigro Marco , McCluskey Jill J. , Mittelhammer Ron C. 
Published: August 2007

AbstractMany economists have estimated hedonic price functions for red and white wine. However, estimating a single hedonic price function imposes the assumption that the implicit prices of the attributes are the same for any red or white wine. We argue that even within these two categories, wines are differentiated, and disregarding this heterogeneity causes an aggregation bias in the estimated implicit prices. By estimating hedonic functions specific to price ranges, we show that the wine market is segmented into several product classes or market segments. We find that a model accounting for the existence of wine classes has greater ability to explain the variability in the data and produces more accurate and interpretable results regarding the implicit prices of the attributes.
Modelling Deforestation and Land‐Use Change: Sparse Data Environments
Authors: Pinto Alessandro De , Nelson Gerald C. 
Published: August 2007

AbstractLand‐use change in developing countries is of great interest to policy‐makers and researchers with diverse interests. Concerns about consequences of deforestation for global climate change and biodiversity have received the most publicity, but loss of wetlands, declining land productivity and watershed management are also problems facing developing countries. Analyses of these problems are especially constrained by lack of data. This article reviews modelling approaches for data‐constrained environments that involve discrete choice methods including neural nets and dynamic programming, and research results that link individual household survey data with satellite images using geographic positioning systems.
The Governance of Rural Land in a Liberalised World
Authors: Hodge Ian 
Published: August 2007

AbstractLiberalisation of agricultural policies reduces the influence of policy on land‐use decisions, but environmental policy objectives remain. Governance provides an approach that recognises the role of institutions and collective action. The formulation of environmental policy objectives in terms of the provision of public goods raises questions as to the role of economic valuation and as to whether the definition of ‘goods’ may misdirect policy attention. An alternative approach relates to ecosystem services and sees management issues in terms of ecosystem resilience and the adaptive governance of socio‐ecological systems. Governance involves a mix of regulation, markets, government incentives and collective action. Regulation sets the domain within which markets operate and social judgements as to property rights are required as a basis for exchanges. Depending on commodity prices, agri‐environment schemes may be required either to reduce agricultural production intensity or to keep land under production. The diffuse nature of the environmental benefits and costs of land uses, the complexity of ecosystems and the need to co‐ordinate land management decisions indicate a role for local adaptive co‐management of land resources. Governments play a major role in supporting the institutional framework within which this can take place.
Spatial Econometric Issues for Bio‐Economic and Land‐Use Modelling
Authors: Holloway Garth , Lacombe Donald , LeSage James P. 
Published: August 2007

AbstractWe survey the literature on spatial bio‐economic and land‐use modelling and assess its thematic development. Unobserved site‐specific heterogeneity is a feature of almost all the surveyed works, and this feature, it seems, has stimulated significant methodological innovation. In an attempt to improve the suitability with which the prototype incorporates heterogeneity, we consider modelling alternatives and extensions. We discuss solutions and conjecture others.