bluuebunny/crossref_metadata_2025_split huggingface dataset:
Maternal serum levels of dehydroepiandrosterone sulfate and labor induction in postterm pregnancies
Authors: Doğanay M. , Erdemoglu E. , Avşar A.F. , Aksakal O.S. 
Published: February 2004

AbstractObjectives: To study the relationship between maternal endogenous dehydroepiandrosterone sulfate (DHEAS) levels, success of labor induction, and Bishop scores in postterm pregnancies. Methods: There were 65 postterm pregnancies. Group 1 consisted of women spontaneously in the active phase of labor, and group 2 of women with hypotonic uterine contractions whose labor was inducted by oxytocin. Levels of DHEAS were studied from venous blood samples. Demographic data and Bishop scores were recorded. Results: The demographic characteristics of patients were similar, but DHEAS levels were higher in group 1 than in group 2 (P<0.001). Linear regression analysis showed a significant relationship between DHEAS and Bishop scores. DHEAS levels in women delivered vaginally were significantly higher than in women delivered by cesarean section. From the receiver operating characteristics (ROC) curve, DHEAS levels might determine the mode of delivery and success of labor induction; however, Bishop scores do not. Conclusions: DHEAS levels may be an important factor influencing the efficiency of labor and the success of labor induction in postterm pregnancies.
Landscape linkages and conservation planning for the black bear in west‐central Florida
Authors: Larkin Jeffery L. , Maehr David S. , Hoctor Thomas S. , Orlando Michael A. , Whitney Karen 
Published: February 2004

AbstractThe Greater Chassahowitzka black bear population is the smallest documented in North America with fewer than 20 individuals. Its future depends on landscape linkages with other bear populations that are separated by denatured habitat. We used a Geographic Information System (GIS) to identify potential landscape linkages between this isolated population and six others in Florida. Pathway lengths ranged from 60–194 km with varying potentials for facilitating black bear dispersal. Each pathway incorporated 35–88% conservation land and encountered at least 11 dispersal bottlenecks. Even pathways that incorporated extensive conservation land encountered bottlenecks that make these linkages potentially unviable. All six pathways, however, passed through ≥95% core black bear habitat. Thus, the infrastructure for a conservation network is still largely intact. The Suwannee pathway provides the best opportunity to restore connectivity between the Greater Chassahowitzka Ecosystem (GCE) and a southward colonising bear population in the Big Bend region. However, intensification of development poses an immediate threat to maintaining connectivity between the GCE and other bear populations in Florida. Through immediate strategic planning and active conservation and restoration measures, many of the generated pathways can provide long‐term connectivity. Least‐cost path analyses can aid in the conservation of wide‐ranging animals by providing managers with a science‐based, empirically derived blueprint of potential landscape linkages.
Developing recovery and monitoring strategies for the endemic Mount Graham red squirrels (Tamiasciurus hudsonicus grahamensis) in Arizona
Authors: Buenau Kate E. , Gerber Leah R. 
Published: February 2004

AbstractAn important challenge in conservation biology is extracting pertinent information from the available data for endangered species. Rarely do we have enough information to precisely determine an organism's risk of extinction and other factors that affect its management. How, then, can we use limited information to make responsible conservation decisions on controversial species such as the Mount Graham red squirrel? We used several analytical approaches to examine 15 years of abundance data for the Mount Graham red squirrel in order to propose recovery criteria and to evaluate alternative conservation strategies. We analysed the historical population dynamics using a diffusion approximation model and showed that the main threat to the population was not the overall growth rate (which may well be greater than 1) but rather the wide range of variation in annual growth rates. We used information on the distribution of growth rates and abundance to classify the species as threatened under the Endangered Species Act (ESA). We then presented a simple demographic model to examine the effects of proportional changes in vital rates on the population growth rate (λ). The elasticity values obtained for Mount Graham red squirrels indicate that the population is far more sensitive to changes in survival rates (particularly adult survival) compared to reproduction. Our analyses suggest that management should focus on refining monitoring techniques, reducing sources of variability, improving the survival of adult animals and filling the gaps in the currently available data.
The molecular systematics and conservation of an endangered carnivore, the Owston's palm civet Chrotogale owstoni (Thomas, 1912) (Carnivora, Viverridae, Hemigalinae)
Authors: Veron G. , Rosenthal S. Heard , Long B. , Roberton S. 
Published: February 2004

AbstractThe Owston's palm civet (Chrotogale owstoni) is one of the least known viverrids. In order to assess the degree of intraspecific variation, we sequenced a fragment of mitochondrial cytochrome b in 26 individuals. We identified 23 haplotypes, indicating a fairly high level of genetic diversity. The phylogenetic analysis yielded two clades supported by eight synapomorphies, suggestive of a north/south geographical divide. Recommendations for captive management cannot be made on the basis of the study results, but the high level of genetic diversity is very encouraging for both field conservation and captive breeding efforts.
Preliminary assessment of the flagship species concept at a small scale
Authors: Caro Tim , Engilis Andrew , Fitzherbert Emily , Gardner Toby 
Published: February 2004

AbstractFlagship species are charismatic species that serve as a symbol and rallying point to stimulate conservation awareness and action but are often used synonymously as de facto umbrella species to delineate reserve boundaries. We tested the extent to which the presence of a flagship species would protect other ‘background species’ at the local scale at which practical decisions about small reserves are often made. Using long term sightings, we identified four 1 km2 sites that are frequently visited by jaguars and by tapirs (flagship species), and by white‐lipped peccaries and spider monkeys (non‐flagship species) in neotropical rainforest in Belize. We then made inventories of five vertebrate taxonomic groups at each site. We found no consistent differences in species richness or abundances of frogs, phyllostomid bats, terrestrial mammals, scansorial mammals or birds across the four sites, except that frog diversity and abundance was higher close to a river at the flagship site where tapirs were found. Since these classic Latin American flagship species fail to encompass particularly high numbers or abundances of vertebrate species at a local scale, they appear to be a poor conservation tool when co‐opted as umbrella species for delineating the location of very small reserves in the neotropics.
Species richness and community composition of songbirds in a tropical forest‐agricultural landscape
Authors: Naidoo Robin 
Published: February 2004

AbstractManagement strategies that attempt to mitigate tropical biodiversity loss require detailed studies of biodiversity in different land‐uses. In this study the community structure and species richness of songbirds was characterised along with the vegetation structure, in three land‐use types in and around a tropical forest reserve in Uganda (intact, mature forest; regenerating secondary forest; smallholder agriculture). Each land‐use type had 30–35 count stations that were sampled twice by means of a 15‐min recording session. In total, 118 bird species were recorded from 192 station counts. Number of species/station was similar in intact and regenerating forest and lower in smallholder agriculture. Songbird communities in intact forest were highly distinct from those in smallholder agriculture and were composed of forest‐dependent species. Communities in regenerating forest were intermediate between intact forest and agriculture, although much closer to intact forest. Generalised Linear Model (GLM) modelling revealed that tree density and distance to the nearest intact forest had strong positive and non‐linear effects on the community composition and forest species richness of songbirds. Simulations using these models showed that agroforestry programmes would not raise tree densities to levels that would shift agricultural songbird communities towards forest communities. Current and best‐case agricultural practices are therefore unlikely to contribute to the conservation of the songbird component of forest biodiversity in this area.
Seroprevalence of pathogens in domestic carnivores on the border of Madidi National Park, Bolivia
Authors: Fiorello Christine V. , Deem Sharon L. , Gompper Matthew E. , Dubovi Edward J. 
Published: February 2004

AbstractThe importance of diseases of domestic animals in the conservation of wildlife is increasingly being recognised. Wild carnivores are susceptible to many of the pathogens carried by domestic dogs and cats and some of these pathogens have caused disease outbreaks and severe population declines in threatened species. The risk of disease spillover from domestic to wild carnivores in South America has not been extensively investigated. This study examined the disease exposure of domestic carnivores living near a protected area in Bolivia. Forty dogs and 14 cats living in three towns on the eastern border of Madidi National Park were sampled. High levels of exposure to canine distemper virus, canine parvovirus, Sarcoptes scabiei and Toxoplasma gondii were found among domestic dogs, with similarly high levels of exposure to feline parvovirus, feline calicivirus and T. gondii being found among domestic cats. If contact occurs between domestic and wild carnivores, disease spillover may represent an important risk for the persistence of wild carnivores in the region. Additional research is therefore necessary to determine if wild carnivores living in proximity to these domestic carnivore populations are being exposed to these pathogens.
Genetic and morphological evolution following a founder event in the dark‐eyed junco,Junco hyemalis thurberi
Authors: Rasner C. A. , Yeh P. , Eggert L. S. , Hunt K. E. , Woodruff D. S. , Price T. D. 
Published: February 2004

AbstractAn isolated population of dark‐eyed juncos,Junco hyemalis,became established on the campus of the University of California at San Diego (UCSD), probably in the early 1980s. It now numbers about 70 breeding pairs. Populations across the entire natural range of the subspeciesJ. h. thurberiare weakly differentiated from each other at five microsatellite loci (FST = 0.01). The UCSD population is significantly different from these populations, the closest of which is 70 km away. It has 88% of the genetic heterozygosity and 63% of the allelic richness of populations in the montane range of the subspecies, consistent with a harmonic mean effective population size of 32 (but with 95% confidence limits from four to > 70) over the eight generations since founding. Results suggest a moderate bottleneck in the early establishment phase but with more than seven effective founders. Individuals in the UCSD population have shorter wings and tails than those in the nearby mountains and a common garden experiment indicates that the morphological differences are genetically based. The moderate effective population size is not sufficient for the observed morphological differences to have evolved as a consequence of genetic drift, indicating a major role for selection subsequent to the founding of the UCSD population.
Experimental Study of the Higher π → π* Transitions of Benzene in Low-Temperature Matrices
Authors: Katz Benjamin , Brith Malka , Sharf Benjamin , Jortner Joshua 
Published: February 2004

In this paper we present the results of an experimental study of the absorption spectrum of benzene and deuterated benzenes in solid Ar, Kr, Xe, and N2 in the spectral region 2800–1700 Å, with special reference to the 2100- and to the 1850-Å transitions. Our main results are:
(a) On the basis of the observed vibrational structure the second excited singlet state of the benzene molecule is assigned to the A1g1 → 1B1u rather than to the A1g1 → 1E2g excitation.
(b) Theoretical calculations of the dynamic electronic–vibrational coupling between the B1u1 and the E1u1 states support the B1u1 assignment of the 2100-Å transition.
(c) The vibrational structure of the 1850-Å A1g1 → 1E1u transition was resolved.
(d) No experimental evidence for Jahn–Teller coupling in the π → π* 1E1u state was observed, in agreement with theoretical analysis.
(e) Information on site splittings for the higher π → π* excitation of benzene in rare-gas solids has accumulated.
(f) Analysis of matrix shifts for the A1g1 → 1B1u and A1g1 → 1E1u transitions indicates that the “solvent effect” is dominated by dispersion interactions.
(g) Information on deuteration effects on the B1u1 and E1u1 energy levels was obtained.
(h) Qualitative information on intramolecular radiationless decay in the two higher π → π* excited states of the benzene molecule has been inferred from the linewidths in the absorption spectrum.
Nature of the External Heavy-Atom Effect on Radiative and Nonradiative Singlet–Triplet Transitions
Authors: Giachino Gary G. , Kearns David R. 
Published: February 2004

The nature of the external heavy-atom effect on radiative and nonradiative singlet–triplet transitions in aromatic hydrocarbons has been investigated experimentally and theoretically. From studies of the perturbed phosphorescence of aromatic hydrocarbons in rigid glass and mixed-crystal systems we conclude that:
(i) Radiative T1 ↔ S0 transitions are much more susceptible to a heavy-atom effect than are the corresponding radiationless transitions.
(ii) The enhancement of the radiative T1 ↔ S0 transitions is due to mixing of excited singlet states associated with the perturber molecule into the triplet state of the perturbed molecule.
(iii) The important pertuber states appear to be highly localized on the heavy atom rather than states which are essentially delocalized [e.g., (π, π*) states].
(iv) It does not seem necessary to invoke charge-transfer interactions to account for the enhancement.
Application of the Coherent Potential Approximation to the Excited Electronic States of Substitutionally Disordered Molecular Crystals
Authors: Hoshen Joseph , Jortner Joshua 
Published: February 2004

In this paper we apply the coherent potential approximation for the calculation of the density of excited electronic states and of the optical properties of a variety of isotopically mixed molecular crystals where the pure crystal exciton band structure and density of state is determined by one, two, and three dimensional interactions. The crystal Hamiltonian is characterized by a random diagonal part and by a translationally invariant off diagonal part. Numerical results are provided for the following systems:
(a) a one dimensional chain in the amalgamation limit, in the persistence case and in the separated bands limit;
(b) the lowest triplet state of naphthalene in the separated bands case;
(c) the lowest singlet state of naphthalene in the amalgamation limit, in the persistence case and in the separated bands limit.
(d) The lowest singlet state of benzene in the persistence case and in the separated bands limit.
These calculations demonstrated the general features of the density of states in substitutionally disordered crystals, such as the erosion of the Van Hove singularities in the band(s), and the nature of the intensity distribution such as number of Davydov components, their relative intensities, location, and widths. The predictions of the CPA for the moments of the density of states and for the optical properties concur with the predictions of the general moment expansion method for a configurationally averaged crystal. A general CPA scheme is provided to handle tertiary mixed crystals, which are of some experimental interest. To account for the concentration dependence of the optical properties of isotopically mixed benzene, we provide a semiquantitative extension of the CPA scheme, where the isotope effect on the environmental shift term is incorporated into the virtual crystal Hamiltonian resulting in concentration dependent diagonal terms in the crystal Hamiltonian.
Hyperfine Spectra of 7Li35Cl and 7Li37Cl
Authors: Gallagher Thomas F. , Hilborn Robert C. , Ramsey Norman F. 
Published: February 2004

Using a newly constructed electric resonance molecular beam apparatus the hyperfine spectra of 7Li35Cl and 7Li37Cl have been measured. At present the most distinctive feature of the apparatus is its 212-m-long C region, allowing linewidths of 300 Hz in this experiment. Some of the details of the design and operation of the apparatus are presented. The spectra were measured in zero magnetic and low electric fields with the results listed below.
Lithium chloride hyperfine constants in kilohertz 7Li35Clν =0ν=1ν=2ν=3eqQCl−3059.51(15)−3442.1(9)−3808(7)−4175(7)eqQLi249.93(50)244.6(20)237(10)225(10)cCl1.946(20)1.98(7)cLi0.956(3)0.92(9)c30.511(20)0.55(6)c40.025(20)0.03(6)7Li37CleqQCl−2410.9(6)−2711(7)eqQLi250.0(10)250(10)cCl1.66(5)cLi1.03(6)c30.42(4)c40.02(3)
Measurements of hyperpolarizabilities for some halogenated methanes
Authors: Finn R. S. , Ward J. F. 
Published: February 2004

dc Electric-field induced optical second-harmonic generation has been measured for CH4, CH3F, CH2F2, CHF3, CF4, CClF3, and CBrF3. For CH4 and CF4 the third order hyperpolarizability χ(−2ω; 0,ω,ω) is obtained directly. For the other (dipolar) molecules, a bond additivity estimate for χ(−2ω; 0,ω,ω) is used to extract the second order hyperpolarizability χ(−2ω;ω,ω).
Results are compared with various data from the literature: calculated hyperpolarizabilities, and measurements of optical harmonic generation, optical mixing and the Kerr effect. The degree of consistency of the experimental data with a bond additivity model is discussed.
Convergent Evolution of Disease Resistance Gene Specificity in Two Flowering Plant Families[W]
Authors: Ashfield Tom , Ong Laura E. , Nobuta Kan , Schneider Christopher M. , Innes Roger W. 
Published: February 2004

AbstractPlant disease resistance (R) genes that mediate recognition of the same pathogen determinant sometimes can be found in distantly related plant families. This observation implies that some R gene alleles may have been conserved throughout the diversification of land plants. To address this question, we have compared R genes from Glycine max (soybean), Rpg1-b, and Arabidopsis thaliana, RPM1, that mediate recognition of the same type III effector protein from Pseudomonas syringae, AvrB. RPM1 has been cloned previously, and here, we describe the isolation of Rpg1-b. Although RPM1 and Rpg1-b both belong to the coiled-coil nucleotide binding site (NBS) Leu-rich repeat (LRR) class of R genes, they share only limited sequence similarity outside the conserved domains characteristic of this class. Phylogenetic analyses of A. thaliana and legume NBS-LRR sequences demonstrate that Rpg1-b and RPM1 are not orthologous. We conclude that convergent evolution, rather than the conservation of an ancient specificity, is responsible for the generation of these AvrB-specific genes.
In-Depth Analysis of the Thylakoid Membrane Proteome ofArabidopsis thalianaChloroplasts: New Proteins, New Functions, and a Plastid Proteome Database[W]
Authors: Friso Giulia , Giacomelli Lisa , Ytterberg A. Jimmy , Peltier Jean-Benoit , Rudella Andrea , Sun Qi , Wijk Klaas J. van 
Published: February 2004

AbstractAn extensive analysis of the Arabidopsis thaliana peripheral and integral thylakoid membrane proteome was performed by sequential extractions with salt, detergent, and organic solvents, followed by multidimensional protein separation steps (reverse-phase HPLC and one- and two-dimensional electrophoresis gels), different enzymatic and nonenzymatic protein cleavage techniques, mass spectrometry, and bioinformatics. Altogether, 154 proteins were identified, of which 76 (49%) were α-helical integral membrane proteins. Twenty-seven new proteins without known function but with predicted chloroplast transit peptides were identified, of which 17 (63%) are integral membrane proteins. These new proteins, likely important in thylakoid biogenesis, include two rubredoxins, a potential metallochaperone, and a new DnaJ-like protein. The data were integrated with our analysis of the lumenal-enriched proteome. We identified 83 out of 100 known proteins of the thylakoid localized photosynthetic apparatus, including several new paralogues and some 20 proteins involved in protein insertion, assembly, folding, or proteolysis. An additional 16 proteins are involved in translation, demonstrating that the thylakoid membrane surface is an important site for protein synthesis. The high coverage of the photosynthetic apparatus and the identification of known hydrophobic proteins with low expression levels, such as cpSecE, Ohp1, and Ohp2, indicate an excellent dynamic resolution of the analysis. The sequential extraction process proved very helpful to validate transmembrane prediction. Our data also were cross-correlated to chloroplast subproteome analyses by other laboratories. All data are deposited in a new curated plastid proteome database (PPDB) with multiple search functions (http://cbsusrv01.tc.cornell.edu/users/ppdb/). This PPDB will serve as an expandable resource for the plant community.
TheYABBYGeneDROOPING LEAFRegulates Carpel Specification and Midrib Development inOryza sativa [W]
Authors: Yamaguchi Takahiro , Nagasawa Nobuhiro , Kawasaki Shinji , Matsuoka Makoto , Nagato Yasuo , Hirano Hiro-Yuki 
Published: February 2004

AbstractIn this article, we report that carpel specification in the Oryza sativa (rice) flower is regulated by the floral homeotic gene DROOPING LEAF (DL) that is distinct from the well-known ABC genes. Severe loss-of-function mutations of DL cause complete homeotic transformation of carpels into stamens. Molecular cloning reveals that DL is a member of the YABBY gene family and is closely related to the CRABS CLAW (CRC) gene of Arabidopsis thaliana. DL is expressed in the presumptive region (carpel anlagen), where carpel primordia would initiate, and in carpel primordia. These results suggest that carpel specification is regulated by DL in rice flower development. Whereas CRC plays only a partial role in carpel identity, DL may have been recruited to have the more essential function of specifying carpels during the evolution of rice. We also show that DL interacts antagonistically with class B genes and controls floral meristem determinacy. In addition, severe and weak dl alleles fail to form a midrib in the leaf. The phenotypic analysis of dl mutants, together with analyses of the spatial expression patterns and ectopic expression of DL, demonstrate that DL regulates midrib formation by promoting cell proliferation in the central region of the rice leaf.