bluuebunny/crossref_metadata_2025_split huggingface dataset:
Field and laboratory biology of the stem‐feeding beetle Thamnurgus euphorbiae (Küster) (Col., Scolytidae) in Italy, a potential biological control candidate of leafy spurge in the USA and Canada
Authors: Campobasso G. , Terragitti G. , Mann K. , Quimby P. C. 
Published: February 2004

Abstract: Thamnurgus euphorbiae overwinters as adults in dry stems of Euphorbia characias until the end of March before exiting through circular holes cut with their mandibles. Females and males appeared in the field at the same time, and the first pairs were observed on 28 March on new stems of E. characias having the open‐flower at the beginning of its development. Throughout the rest of April it was possible to find and collect the fairly abundant adults. Mating occurs on new stems of the host plant and females walk up towards the top of the stem and start to mine the centre of it in order to penetrate. Oviposition occurs in new stems and eggs are laid singly along the interior of the stem; females laid 35–85 eggs. Upon hatching, larvae started feeding on vascular bundles and the inner cortex. There are three larval instars, and pupation occurred in the stem of the host plant; this insect is univoltine. Thamnurgus euphorbiae has been accepted by the Technical Advisory Group for Biological Control Agents of Weeds for release as a biological control agent of leafy spurge in the US. Prior to this study the biology of T. euphorbiae was unknown.
Comparative growth inhibitory and antifeedant effects of plant extracts and pure allelochemicals on four phytophagous insect species
Authors: Akhtar Y. , Isman M. B. 
Published: February 2004

Abstract:Antifeedant and growth inhibitory effects of crude plant extracts (Melia volkensii and Origanum vulgare) and pure allelochemicals (digitoxin, cymarin, xanthotoxin, toosendanin, thymol and trans‐anethole) were investigated in the cabbage looper (Trichoplusia ni), and in the armyworm (Pseudaletia unipuncta) using different bioassays. Antifeedant effects of M. volkensii, O. vulgare and thymol were investigated in larvae of the diamondback moth (Plutella xylostella), and of O. vulgare and thymol in the Mexican bean beetle (Epilachna varivestis), using leaf disc choice bioassays. M. volkensii was the most potent growth inhibitor for T. ni and P. unipuncta (dietary EC50 = 7.6 and 12.5 p.p.m., respectively) of all the test substances. Cymarin was the second most potent growth inhibitor (EC50 = 132.0 p.p.m.) for T. ni. The most effective feeding deterrents for third instar T. ni larvae were xanthotoxin andM. volkensii (DC50 = 0.9 and 8.3 μg/cm2, respectively). M. volkensii was also the most potent feeding deterrent for third instar P. unipuncta, P. xylostella and adult E. varivestis (DC50 = 10.5, 20.7 and 2.3 μg/cm2, respectively). Because of interspecific differences in response to feeding deterrents and the lack of a strong relationship between EC50 and DC50 values, we recommend testing a battery of bioassay species with candidate compounds and the use of more than one bioassay. Based on their growth inhibitory and feeding deterrent properties, some of these plant extracts and pure allelochemicals have potential for use as alternative crop protectants against a number of pest species.
Near Hartree—Fock Calculations of the Force Constants and Dipole Moment Derivatives in Methane
Authors: Meyer W. , Pulay P. 
Published: February 2004

The complete force field of methane is calculated from SCF—MO wavefunctions by applying the force method. Many different Gaussian basis sets are used, and the influence of different types of atomic functions on the force constants is discussed. The deviation of the calculated force constants from the observed values is similar for all treated basis sets. Therefore it is concluded that the deviation is mainly due to the neglect of correlation effects, and that there is little point in using very extended basis sets in Hartree-Fock calculations. The energy of our best calculation is estimated to be at most 0.01 a.u. above the HF limit. The results of this calculation are as follows (experimental values in brackets):
(1) Force constants in millidynes per angstrom: F11=5.578(5.842), F22=0.537(0.486), F33=5.382(5.383), F34=0.202(0.206), F44=0.512(0.458);
(2) Dipole moment derivatives in debyes per angstrom: μ3=−0.977 (± 0.833), μ4=−0.329 (± 0.373).
The interpretation of the force field is discussed on the basis of a population analysis.
Some new energy formulas for atoms and molecules
Authors: Politzer Peter , Parr Robert G. 
Published: February 2004

An exact formula for the nonrelativistic ground-state energy of an atom or molecule is derived: E=12 ∑ A ZA2(∂ φA∂ rA)rA=0−12 ∑ A ∫ Z′ZAA=0 Z′A2[∂∂Z′A(∂φA∂rA)rA=0]NdZ′A.
The function φA is defined for each nucleus A by φA = rA V/ZA, where ZA is the nuclear charge and V is the total electrostatic potential produced by the electrons and nuclei at a point rA measured from nucleus A. φA represents the screening of nucleus A by the electrons and other nuclei. The integration must be carried out over an isoelectronic path, the number of electrons being equal to the actual number N in the atom or molecule being considered. Equation (I) gives the molecular energy as a sum of atomiclike terms. It is shown that atomic energies can be calculated with remarkable accuracy with the equation E=37Z2(∂ φ / ∂ r)r=0, using Hartree-Fock values for (∂φ/∂r)r=0. Equation (II) is identical in form with a relationship in the Thomas-Fermi theory of atoms. These equations emphasize the dependence of atomic and molecular energies upon the electrostatic potentials at the nuclei. This is further discussed and illustrated. A semiempirical formula for the energy of an atom as a power series in Z1/3 is also presented.
Hydrogen Flash Lamps
Authors: Berlman I. B. , Steingraber O. J. , Benson M. J. 
Published: February 2004

Many hydrogen-filled lamps have been tested and the effect of each of several parameters on the intensity and shape of the radiation pulse determined. The parameters were gas pressure, type of gas (hydrogen or deuterium), tube voltage, and electrode gap distance. A flash lamp has been designed and built which is simple, inexpensive, and easily disassembled.
Our results show that deuterium-filled tubes with 2 mm gaps emit about (65±10)% more photons per discharge than hydrogen-filled tubes operated under similar conditions. The parameters favorable for a high intensity discharge are large gap with deuterium gas—for a rapid discharge, high pressure and voltage.
Diet, nutrition and the prevention of cancer
Authors: Key Timothy J , Schatzkin Arthur , Willett Walter C , Allen Naomi E , Spencer Elizabeth A , Travis Ruth C 
Published: February 2004

AbstractObjective:To assess the epidemiological evidence on diet and cancer and make public health recommendations.Design:Review of published studies, concentrating on recent systematic reviews, meta-analyses and large prospective studies.Conclusions and recommendations:Overweight/obesity increases the risk for cancers of the oesophagus (adenocarcinoma), colorectum, breast (postmenopausal), endometrium and kidney; body weight should be maintained in the body mass index range of 18.5–25?kg/m2, and weight gain in adulthood avoided. Alcohol causes cancers of the oral cavity, pharynx, oesophagus and liver, and a small increase in the risk for breast cancer; if consumed, alcohol intake should not exceed 2?units/d. Aflatoxin in foods causes liver cancer, although its importance in the absence of hepatitis virus infections is not clear; exposure to aflatoxin in foods should be minimised. Chinese-style salted fish increases the risk for nasopharyngeal cancer, particularly if eaten during childhood, and should be eaten only in moderation. Fruits and vegetables probably reduce the risk for cancers of the oral cavity, oesophagus, stomach and colorectum, and diets should include at least 400?g/d of total fruits and vegetables. Preserved meat and red meat probably increase the risk for colorectal cancer; if eaten, consumption of these foods should be moderate. Salt preserved foods and high salt intake probably increase the risk for stomach cancer; overall consumption of salt preserved foods and salt should be moderate. Very hot drinks and foods probably increase the risk for cancers of the oral cavity, pharynx and oesophagus; drinks and foods should not be consumed when they are scalding hot. Physical activity, the main determinant of energy expenditure, reduces the risk for colorectal cancer and probably reduces the risk for breast cancer; regular physical activity should be taken.
The Arabidopsis thaliana Dihydroxyacetone Phosphate Reductase Gene SUPPRESSOR OF FATTY ACID DESATURASE DEFICIENCY1 Is Required for Glycerolipid Metabolism and for the Activation of Systemic Acquired Resistance[W]
Authors: Nandi Ashis , Welti Ruth , Shah Jyoti 
Published: February 2004

Abstract
Systemic acquired resistance (SAR) is a broad-spectrum resistance mechanism in plants that is activated in naive organs after exposure of another organ to a necrotizing pathogen. The organs manifesting SAR exhibit an increase in levels of salicylic acid (SA) and expression of the PATHOGENESIS-RELATED1 (PR1) gene. SA signaling is required for the manifestation of SAR. We demonstrate here that the Arabidopsis thaliana suppressor of fatty acid desaturase deficiency1 (sfd1) mutation compromises the SAR-conferred enhanced resistance to Pseudomonas syringae pv maculicola. In addition, the sfd1 mutation diminished the SAR-associated accumulation of elevated levels of SA and PR1 gene transcript in the distal leaves of plants previously exposed to an avirulent pathogen. However, the basal resistance to virulent and avirulent strains of P. syringae and the accumulation of elevated levels of SA and PR1 gene transcript in the pathogen-inoculated leaves of sfd1 were not compromised. Furthermore, the application of the SA functional analog benzothiadiazole enhanced disease resistance in the sfd1 mutant plants. SFD1 encodes a putative dihydroxyacetone phosphate (DHAP) reductase, which complemented the glycerol-3-phosphate auxotrophy of the DHAP reductase–deficient Escherichia coli gpsA mutant. Plastid glycerolipid composition was altered in the sfd1 mutant plant, suggesting that SFD1 is involved in lipid metabolism and that an SFD1 product lipid(s) is important for the activation of SAR.
The WRKY70 Transcription Factor: A Node of Convergence for Jasmonate-Mediated and Salicylate-Mediated Signals in Plant Defense[W]
Authors: Li Jing , Brader Günter , Palva E. Tapio 
Published: February 2004

AbstractCross talk between salicylic acid (SA)– and jasmonic acid (JA)–dependent defense signaling has been well documented in plants, but how this cross talk is executed and the components involved remain to be elucidated. We demonstrate that the plant-specific transcription factor WRKY70 is a common component in SA- and JA-mediated signal pathways. Expression of WRKY70 is activated by SA and repressed by JA. The early induction of WRKY70 by SA is NPR1-independent, but functional NPR1 is required for full-scale induction. Epistasis analysis suggested that WRKY70 is downstream of NPR1 in an SA-dependent signal pathway. Modulation of WRKY70 transcript levels by constitutive overexpression increases resistance to virulent pathogens and results in constitutive expression of SA-induced pathogenesis-related genes. Conversely, antisense suppression of WRKY70 activates JA-responsive/COI1-dependent genes. The effect of WRKY70 is not caused by subsequent changes in SA or JA levels. We suggest that WRKY70 acts as an activator of SA-induced genes and a repressor of JA-responsive genes, integrating signals from these mutually antagonistic pathways.
TheArabidopsis thaliana ABSCISIC ACID-INSENSITIVE8Locus Encodes a Novel Protein Mediating Abscisic Acid and Sugar Responses Essential for Growth[W]
Authors: Brocard-Gifford Inès , Lynch Tim J. , Garcia M. Emily , Malhotra Bhupinder , Finkelstein Ruth R. 
Published: February 2004

AbstractAbscisic acid (ABA) regulates many aspects of plant growth and development, yet many ABA response mutants present only subtle phenotypic defects, especially in the absence of stress. By contrast, the ABA-insensitive8 (abi8) mutant, isolated on the basis of ABA-resistant germination, also displays severely stunted growth, defective stomatal regulation, altered ABA-responsive gene expression, delayed flowering, and male sterility. The stunted growth of the mutant is not rescued by gibberellin, brassinosteroid, or indoleacetic acid application and is not attributable to excessive ethylene response, but supplementing the medium with Glc improves viability and root growth. In addition to exhibiting Glc-dependent growth, reflecting decreased expression of sugar-mobilizing enzymes, abi8 mutants are resistant to Glc levels that induce developmental arrest of wild-type seedlings. Studies of genetic interactions demonstrate that ABA hypersensitivity conferred by the ABA-hypersensitive1 mutation or overexpression of ABI3 or ABI5 does not suppress the dwarfing and Glc dependence caused by abi8 but partially suppresses ABA-resistant germination. By contrast, the ABA-resistant germination of abi8 is epistatic to the hypersensitivity caused by ethylene-insensitive2 (ein2) and ein3 mutations, yet ABI8 appears to act in a distinct Glc response pathway from these EIN loci. ABI8 encodes a protein with no domains of known function but belongs to a small plant-specific protein family. Database searches indicate that it is allelic to two dwarf mutants, elongation defective1 and kobito1, previously shown to disrupt cell elongation, cellulose synthesis, vascular differentiation, and root meristem maintenance. The cell wall defects appear to be a secondary effect of the mutations because Glc treatment restores root growth and vascular differentiation but not cell elongation. Although the ABI8 transcript accumulates in all tested plant organs in both wild-type and ABA response mutants, an ABI8-β-glucuronidase fusion protein is localized primarily to the elongation zone of roots, suggesting substantial post-transcriptional regulation of ABI8 accumulation. This localization pattern is sufficient to complement the mutation, indicating that ABI8 acts either at very low concentrations or over long distances within the plant body.
Retarded protein folding of deficient human α1‐antitrypsin D256V and L41P variants
Authors: Jung Chan‐Hun , Na Yu‐Ran , Im Hana 
Published: February 2004

Abstractα1‐Antitrypsin is the most abundant protease inhibitor in plasma and is the archetype of the serine protease inhibitor superfamily. Genetic variants of human α1‐antitrypsin are associated with early‐onset emphysema and liver cirrhosis. However, the detailed molecular mechanism for the pathogenicity of most variant α1‐antitrypsin molecules is not known. Here we examined the structural basis of a dozen deficient α1‐antitrypsin variants. Unlike most α1‐antitrypsin variants, which were unstable, D256V and L41P variants exhibited extremely retarded protein folding as compared with the wild‐type molecule. Once folded, however, the stability and inhibitory activity of these variant proteins were comparable to those of the wild‐type molecule. Retarded protein folding may promote protein aggregation by allowing the accumulation of aggregation‐prone folding intermediates. Repeated observations of retarded protein folding indicate that it is an important mechanism causing α1‐antitrypsin deficiency by variant molecules, which have to fold into the metastable native form to be functional.
Read All About It! Understanding the Role of Media in Economic Development
Authors: Coyne Christopher J. , Leeson Peter T. 
Published: February 2004

SummaryThis paper explores the role of media in economic development. In particular, we seek to outline the conditions under which the media contributes to the successful adoption of policies aimed at economic progress. Our core thesis is that successful economic development requires the coordination of efforts by politicians with the interests of the populace on policies that bring about economic growth. However, the nature of the relationship between political actors in charge of reform is characterized by a conflict of interests. The role of media as a key mechanism for transforming these situations of conflict into situations of coordination between politicians and the populace is analyzed. Specifically, we consider four factors — media autonomy, legal structure, quality of the media and consumer demand — and how they impact media as a coordination‐enhancing mechanism.Historical examples of the media in developing countries provide further insight into the circumstances necessary for media to be an effective coordination‐enhancing mechanism. We consider the impact of a free media in cases where successful economic development has occurred — Hungary and Poland. We also consider the Ukraine as a case where media has failed to overcome the conflict characterizing the reform process, and Bulgaria as a situation where politicians and the populace have failed to coordinate around ‘good’ reforms despite having a free media. Our paper concludes with some policy recommendations regarding the achievement of a free and effective media.
The Institutional Determinants of Bilateral Trade Patterns
Authors: De Groot Henri L. F. , Linders Gert‐Jan , Rietveld Piet , Subramanian Uma 
Published: February 2004

SummaryThis paper studies the effect of institutions on trade flows, using a gravity model approach. Standard gravity equations incorporate factors such as geographical proximity, language, trade policy and common history as explanatory factors for variation in bilateral trade that reflect the costs of trade across geographical and cultural distance. We extend this type of analysis by focusing on the relevance of the quality of governance and the extent of familiarity with the resulting framework of rules and norms in explaining variation in bilateral trade patterns. More specifically, we test whether institutional homogeneity and institutional quality have an independent impact on the trade volume between pairs of countries. We find that having a similar institutional framework promotes bilateral trade by 13%, on average. Furthermore, a better quality of formal institutions tends to coincide with more trade. Depending on being either importer or exporter, an increase in overall institutional quality of one standard deviation from the mean leads to an estimated increase of 30–44% in bilateral trade.
Migration, Self‐Selection and Income Inequality: An International Analysis
Authors: Liebig Thomas , Sousa‐Poza Alfonso 
Published: February 2004

SummaryIn the context of an emerging focus on highly skilled migration throughout the OECD area, the question under which circumstances migrants can be expected to be relatively skilled is of particular importance. Borjas has analysed the relation between the income distribution and the skills of migrants. His self‐selection model predicts that immigrants from countries with a higher income inequality tend to be negatively selected (i.e., less skilled than the average worker in both host and source countries). According to other models based on the human capital theory of migration, however, migrants can be expected to be relatively skilled. Empirical tests of Borjas' much‐disputed negative self‐selection hypothesis generally rely on immigration data, particularly to the US, and may therefore be biased due to host‐country specifics such as network migration and the impact of migration policy. This paper analyses the relationship between country‐specific emigration propensities and each country's score on various indices of income inequality with a rich international microdata set. The main result is that highly‐skilled persons are more inclined to migrate, though a higher income inequality attenuates the positive selectivity.
Healthy improvement of ionic balance with industrial processing of vegetables
Authors: Martínez‐Tomé M. , Vera A. 
Published: February 2004

SummaryThe anion (chloride, nitrate, phosphate, sulphate and oxalate) composition of water used to wash spinach during processing (frozen and canned) was determined by Ion Chromatography (IC). The results showed the anions to increase in the water during washing of raw spinach and during the freezing and canning processes. Thus the anion content of the spinach itself was reduced. This observation has important health implications, particularly for people suffering with kidney stones for whom it is essential to seek ways of reducing oxalate intake. It is also important for improving quality and reducing the level of contaminants (such as nitrates) according to EU Commission proposed levels. The lower concentration of nitrates, oxalates and other toxic components is especially beneficial for those who follow the recommendation to eat five or more servings of a combination of vegetables and fruits, especially green and yellow vegetables and citrus fruits each day.
The accuracy of electronic working length determination
Authors: Hoer D. , Attin T. 
Published: February 2004

AbstractAim  To determine in vivo the accuracy of two impedance quotient apex locators under clinical conditions.Methodology  Electronic working length determination was carried out before extraction in 79 human teeth with 93 root canals. In 51 root canals, the determination was performed using the apex locator Justy II® (Hager & Werken, Duisburg, Germany); in 42 canals, the apex locator Endy 5000® (Loser, Leverkusen, Germany) was used. A root canal instrument was fixed at working length with composite material prior to extraction followed by the exposure of a radiograph. After histological preparation of the apical region, the teeth were examined under a light microscope. The distance of the file tips to the target intervals ‘minor foramen – major foramen’ and ‘apical canal constriction’ was determined. These values were compared with the calculated working lengths, determined by radiographic assessment. The data were statistically analysed by a paired t‐test.Results  For both apex locators and both target intervals, no significant differences between the electronic and radiographical assessments were recorded. The probability of determining the area between minor and major foramen was 82.4% for Justy II and 81% for Endy 5000. However, accurate determination of the apical constriction was only successful in 51% (Justy II) and 64.3% (Endy 5000) of canals. Variation of the inaccurate measurements was higher for Endy 5000 than for Justy II.Conclusions  Under clinical conditions, it is possible to determine the region between the minor and major apical foramen with electronic length measuring devices (ELD). However, use of these devices does not result in precise determination of the apical constriction.
The use of glass ionomer cements in both conventional and surgical endodontics
Authors: De Bruyne M. A. A. , De Moor R. J. G. 
Published: February 2004

AbstractThe capacity to bond to dental tissues, especially to dentine, their long‐term fluoride release and their biocompatibility make glass ionomer cements (GICs) advantageous for use in endodontics, as well as in restorative dentistry. This review provides information on the basic properties of GICs, such as adhesion, antimicrobial effects and biocompatibility, particularly as they relate to use in endodontics. Indications for the use of GICs in endodontics are orthograde root canal sealing, root‐end filling, repair of perforations and root resorption defects, treatment of vertical fractures and maintenance of the coronal seal. The paper includes a review on each of these indications. It is concluded that in spite of the critical handling characteristics and the inconclusive findings regarding sealing ability and antimicrobial activity, there is substantial evidence to confirm their satisfactory clinical performance. Both soft tissue and bone compatibility make them suitable for use during endodontic surgery.