bluuebunny/crossref_metadata_2025 huggingface dataset:
High‐resolution seismic reflection imaging of a thin, diamondiferous kimberlite dyke
Authors: Hammer Philip T. C. , Clowes Ron M. , Ramachandran Kumar
Published: September 2004

Seismic reflection techniques are, for the first time, used to image a thin, diamondiferous kimberlite dyke from subcrop to depths greater than 1300 m. Geophysical exploration for kimberlite deposits typically involves airborne potential field surveys that are well suited for detecting vertical outcropping pipes but often fail to reveal thin, subhorizontal dykes and sills. Because seismic techniques are especially well suited for mapping structures that have shallow dips and strong impedance contrasts, a feasibility study and seismic reflection survey were undertaken on the diamondiferous Snap Lake dyke (Northwest Territories, Canada) to evaluate the potential for using seismic techniques on these targets. The dyke (average thickness 2–3 m) provides an excellent test site because a drilling program has defined the gross dyke geometry and provides core samples from the kimberlite and host rocks. The feasibility study involved measuring P‐velocity and density of selected cores. Using these data, reflectivity and finite‐difference synthetic seismogram techniques were used to explore the resolution limitations and determine the acquisition parameters for a reflection survey. The seismic survey included two 2D lines designed to obtain comparative data sets from different sources (explosives and vibroseis) and ground types (land or lake‐ice). The explosive‐source land data yielded a superb image of the thin dyke. The vibroseis data, however, detected the dyke only when sources and geophones were on land; the dyke was not imaged beneath the ice due to reverberation and attenuation effects. Correlations are observed between reflection attributes and dyke properties (thickness, structure, and physical properties). The results demonstrate that, in the appropriate situation, seismic methods have great potential for use in kimberlite exploration, subsurface mapping, and detailed imaging for mine development purposes.
Joint inversion of transient‐pressure and dc resistivity measurements acquired with in‐situ permanent sensors: A numerical study
Authors: Alpak Faruk O. , Torres‐Verdín Carlos , Habashy Tarek M.
Published: September 2004

We develop a quantitative methodology to interpret jointly in‐situ transient‐pressure and dc resistivity measurements acquired in a hypothetical water injection experiment, with the goal of displacing oil in a hydrocarbon‐bearing formation. The assumed measurement acquisition system consists of enforcing time‐variable flow rates while injecting water into the surrounding rock formations, thereby producing a sequence of repeated transient‐pressure pulses. In‐situ dc resistivity measurements are acquired at the end of every flow‐rate pulsing sequence. The objective of the experiment is to estimate the spatial distributions of absolute fluid permeability and electrical resistivity. Geophysical inverse theory is used to account for the presence of noisy measurements.

Synthetic data with noise are inverted to assess the relative benefits of different types of sensor geometries in axisymmetric models of permeability and electrical resistivity. Results strongly suggest that cooperative inversion of in‐situ transient‐pressure and dc resistivity measurements reduces nonuniqueness in the estimation of resistivity and absolute permeability governed by dynamic fluid‐flow phenomena. This leads to a more accurate estimate of permeability and resistivity compared to separate inversion of each data type.
Effect of bird maneuver on frequency‐domain helicopter EM response
Authors: Fitterman David V. , Yin Changchun
Published: September 2004

Bird maneuver, the rotation of the coil‐carrying instrument pod used for frequency‐domain helicopter electromagnetic surveys, changes the nominal geometric relationship between the bird‐coil system and the ground. These changes affect electromagnetic coupling and can introduce errors in helicopter electromagnetic (HEM) data. We analyze these effects for a layered half‐space for three coil configurations: vertical coaxial, vertical coplanar, and horizontal coplanar. Maneuver effect is shown to have two components: one that is purely geometric and another that is inductive in nature. The geometric component is significantly larger. A correction procedure is developed using an iterative approach that uses standard HEM inversion routines. The maneuver effect correction reduces inversion misfit error and produces laterally smoother cross sections than obtained from uncorrected data.
Inversion of 3D electromagnetic data in frequency and time domain using an inexact all‐at‐once approach
Authors: Haber Eldad , Ascher Uri M. , Oldenburg Douglas W.
Published: September 2004

We present a general formulation for inverting frequency‐ or time‐domain electromagnetic data using an all‐at‐once approach. In this methodology, the forward modeling equations are incorporated as constraints and, thus, we need to solve a constrained optimization problem where the parameters are the electromagnetic fields, the conductivity model, and a set of Lagrange multipliers. This leads to a much larger problem than the traditional unconstrained formulation where only the conductivities are sought. Nevertheless, experience shows that the constrained problem can be solved faster than the unconstrained one. The primary reasons are that the forward problem does not have to be solved exactly until the very end of the optimization process, and that permitting the fields to be away from their constrained values in the initial stages introduces flexibility so that a stationary point of the objective function is found more quickly. In this paper, we outline the all‐at‐once approach and apply it to electromagnetic problems in both frequency and time domains. This is facilitated by a unified representation for forward modeling for these two types of data. The optimization problem is solved by finding a stationary point of the Lagrangian. Numerically, this leads to a nonlinear system that is solved iteratively using a Gauss‐Newton strategy. At each iteration, a large, indefinite matrix is inverted, and we discuss how this can be accomplished. As a test, we invert frequency‐domain synthetic data from a grounded electrode system that emulates a field CSAMT survey. For the time domain, we invert borehole data obtained from a current loop on thesurface.
A comparison of the inductive‐limit footprints of airborne electromagnetic configurations
Authors: Reid James E. , Vrbancich Julian
Published: September 2004

An inductive‐limit model has been used to determine footprint sizes for a variety of common airborne electromagnetic‐survey geometries. The model accounts both for variations in the height and orientation of the electromagnetic transmitter, and for electromagnetic coupling between the induced current system and the receiver. Horizontal magnetic‐dipole transmitters are shown to have a smaller footprint than vertical magnetic‐dipole sources. We show that footprint sizes for the vertical coaxial and vertical coplanar geometries are essentially identical, provided the transmitter‐receiver separation is much less than the transmitter height. The inductive‐limit horizontal‐component footprint for a fixed‐wing horizontal‐loop transmitter with a towed‐bird receiver is shown to be two‐thirds of that for the vertical component.
Inversion of gravity‐field inclination to map the basement relief of sedimentary basins
Authors: Mendonça Carlos Alberto
Published: September 2004

This paper presents a method to map the basement relief of homogeneous sedimentary basins that does not require the knowledge of the basin density contrast. To reach this task, the proposed method relies on the invariance of the inclination of the anomalous gravity field with the density contrast caused by models constituted by two homogeneous media. This invariance occurs because the density contrast appears as a constant factor in both vertical and horizontal gravity components, therefore being canceled out when these components are divided during the evaluation of the field inclination. For such media, the field inclination is independent of the density contrast, thus allowing the source geometry reconstruction even when the density contrast is unknown. As the inclination is rarely measured, the gravity anomaly (i.e., the field vertical component) is initially used to compute the horizontal component of the gravity field by applying a suitable linear transform. The field inclination is estimated from both components and then used to invert the source geometry by fitting the inclination values under the geologic constraints attributed to the causative sources. In this process, the density contrast is not required nor introduced as an unknown parameter in the formulated inverse problem. Moreover, it can be estimated later by solving a new inverse problem where the source geometry determined from the inverted inclination is fixed and the constant density contrast is determined by fitting the gravity anomaly. This paper applies such ideas to map the basement relief of a sedimentary basin and to estimate its density contrast. The inversion is implemented by a random search procedure that excludes extreme models, and imposes constraints that the unknown interface is smooth everywhere and assumes known depth values at isolated points investigated by wells. The proposed technique is tested with synthetic noisy data from homogeneous and heterogeneous basin models and is applied to invert a gravity profile from the Recôncavo Basin, Brazil. The results from the real data application are compared with well data and previously published results.
Seismic‐while‐drilling by using dual sensors in drill strings
Authors: Poletto Flavio , Malusa Massimo , Miranda Francesco , Tinivella Umberta
Published: September 2004

Drill‐string waves can be successfully used as reference pilot signals for drill‐bit seismic‐while‐drilling (SWD) purposes. The seismic signals obtained by correlating pilot and geophone measurements are disturbed by the drill‐string reverberations because the pilot waves are reflected at each interface between string sections with different acoustic impedances. Inverse filtering of these reflections, using a reference‐pilot deconvolution calculated in the presence of additional noise, may cause signal distortion. To overcome this problem, we consider using dual‐sensor measurements in the drill string to remove the reflections of the drill‐bit waves in the acquisition phase and to improve pilot deconvolution. We measure acceleration and strain of drill‐string dual fields, which have opposite reflection coefficients and, in a string of constant elastic properties, the same transmission coefficients. These quantities are scaled to fit the amplitude of the direct arrivals, summed to remove the reflections in the drill string and in the rig, and may be deconvolved by Einstein deconvolution to characterize the reflection coefficient between the drill bit and the formation. Synthetic numerical examples and real measurements acquired downhole in a location close to the bit show that upgoing and downgoing drill‐string pilots can be separated using dual fields and jointly used to improve the SWD seismograms.
The optimization approach to lithological tomography: Combining seismic data and petrophysics for porosity prediction
Authors: Bosch Miguel
Published: September 2004

Least‐squares model optimization methods are commonly used to estimate physical media properties by fitting geophysical data with nonlinear models. I extend this formulation to joint estimation of physical properties and lithological description of the media. Incorporation of petrophysical information within the inversion scheme provides the coupling between lithology and media physics by describing the geostatistical relation between them. The resulting procedure adjusts iteratively the joint model to simultaneously fit geophysical data, the petrophysical statistical medium description, and prior information on the lithology, following equations derived for the Newton's optimization method. Although more calculations are required to incorporate the additional information and estimate the model update, the algebraic system of linearized equations can be transformed appropriately to remain within the same dimensions of the conventional inverse formulation. In the particular case when the petrophysical transform is linear (i.e., the function of lithological parameters that provides the expected values of the physical parameters), the lithological inversion equations are equivalent to the corresponding equations of a conventional inversion followed with the inverse petrophysical transform. I illustrate the methodology with synthetic examples of porosity‐impedance estimation from zero offset seismic data, using Wyllie's transform to construct the statistical relationship between porosity and impedance. When the porosity range of the test models is on the nonlinear part of the petrophysical transform, the lithological inversion performs significantly better than the conventional inversion. When the porosity range is on an almost linear part of the transform, the performances are equivalent for both approaches.
Angle‐domain common‐image gathers for migration velocity analysis by wavefield‐continuation imaging
Authors: Biondi Biondo , Symes William W.
Published: September 2004

We analyze the kinematic properties of offset‐domain common image gathers (CIGs) and angle‐domain CIGs (ADCIGs) computed by wavefield‐continuation migration. Our results are valid regardless of whether the CIGs were obtained by using the correct migration velocity. They thus can be used as a theoretical basis for developing migration velocity analysis (MVA) methods that exploit the velocity information contained in ADCIGs.

We demonstrate that in an ADCIG cube, the image point lies on the normal to the apparent reflector dip that passes through the point where the source ray intersects the receiver ray. The image‐point position on the normal depends on the velocity error; when the velocity is correct, the image point coincides with the point where the source ray intersects the receiver ray. Starting from this geometric result, we derive an analytical expression for the expected movements of the image points in ADCIGs as functions of the traveltime perturbation caused by velocity errors. By applying this analytical result and assuming stationary raypaths (i.e., small velocity errors), we then derive two expressions for the residual moveout (RMO) function in ADCIGs. We verify our theoretical results and test the accuracy of the proposed RMO functions by analyzing the migration results of a synthetic data set with a wide range of reflector dips.

Our kinematic analysis leads also to the development of a new method for computing ADCIGs when significant geological dips cause strong artifacts in the ADCIGs computed by conventional methods. The proposed method is based on the computation of offset‐domain CIGs along the vertical‐offset axis and on the “optimal” combination of these new CIGs with conventional CIGs. We demonstrate the need for and the advantages of the proposed method on a real data set acquired in the North Sea.
Fast migration/inversion with multivalued ray fields: Part 1—Method, validation test, and application in 2D to Marmousi
Authors: Xu Sheng , Lambaré Gilles
Published: September 2004

We address the problem of building an efficient algorithm for ray‐based migration/inversion in complex media characterized by multivalued traveltime. Since the multivalued ray maps can be computed by wavefront construction, the key point lies in the interpolation of these multivalued coarse maps. For this goal we propose two new strategies. The first one is based on an interpolation of the ray field after identifying the ray branches on the elementary cells of the coarse grid; the second is based on an extrapolation of the arrivals from the coarse grid points. Both strategies are evaluated in two dimensions with the Marmousi data set, demonstrating the CPU efficiency and accuracy of both approaches. Since they both consider multiarrivals locally, the associated overhead cost with respect to a single‐arrival implementation is quite low (twice the computing time of the Marmousi test case). The application also reveals that the new interpolation strategy is more efficient in terms of CPU time compared to the extrapolation strategy but at the expense of a more complex numerical implementation and less accurate results.
Zn/CeCl3.7H2O-TBPB: A New and ‘Green’ Promoter System for Rapid and Regioselective Thiolyzation of 1,2-Epoxides with Aryl Disulfides
Authors: Khosropour Ahmad R , Khodaei Mohammad M , Ghozati Kazem
Published: September 2004

A new, efficient, clean, and regioselective ‘one-pot’ procedure for thiolyzation of epoxides with aryl disulfides catalyzed by cerium(III) chloride heptahydrate immobilized on tetrabutyl phosphonium bromide as an ionic liquid is reported.
Crystallization Process of TiO2 Nanoparticles in an Acidic Solution
Authors: Shin Hyunho , Jung Hyun Suk , Hong Kug Sun , Lee Jung-Kun
Published: September 2004

Hydrolysis of titanium tetraisopropoxide followed by condensation at 30 °C yields amorphous TiO2. Addition of nitric acid for peptization greatly accelerates the rate of amorphous to anatase conversion, resulting in an anatase with locally imperfect atomic structure. Further conversion to rutile in acidic solution has been observed and a plausible phase transformation process has been postulated.
Synthesis and Characterization of Barium Sulfate Nanotubes
Authors: Lu Xiao-Jing , Wei Xian-Wen , Sun Jian , Ni Yong-Hong , Zhao Guang-Chao , Ye Yin
Published: September 2004

Tubular barium sulfate, having diameters in the range of 200–350 nm and length up to 30 microns, was fabricated by a nanochannel reactor and characterized by scanning electron microscope, transmission electron microscope, and X-ray diffractometer. The process is very simple, efficient and easy to control, which can be used to prepare a wide range of tubular inorganic nanomaterials.
Microwave-assisted Synthesis of Nanocrystalline Metal Sulfides Using an Ionic Liquid
Authors: Jiang Ya , Zhu Ying-Jie
Published: September 2004

Nanoparticles of metal sulfides (ZnS and CdS) have been successfully synthesized using an ionic liquid 1-n-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) under microwave heating at 100 °C for 10 min. The products were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM).
Preparation and Enhanced Electrochromic Property of Three-dimensional Ordered Mesostructured Mixed Tungsten–Titanium Oxides
Authors: Yuan Minjia , Lu Yidong , Tian Bozhi , Yang Haifeng , Tu Bo , Kong Jilie , Zhao Dongyuan
Published: September 2004

Ordered three-dimensional (3-D) cage-like mesoporous mixed tungsten–titanium oxides (WO3–TiO2) with relatively high surface area (152 m2g−1) have been synthesized by employing Pluronic F108 triblock copolymer as a structure-directing agent via “acid-base pairs” strategy. Such materials exhibit enhanced electrochromic properties with the contrast ratio (Tb/Tc) of ≈1.8 at 550 nm.
Synthesis of Dense Y-zeolite Bulks with Large Surface Area Using a Hydrothermal Hot-pressing (HHP) Process
Authors: Nakahira Atsushi , Takezoe Shinichi , Yamasaki Yuki
Published: September 2004

Highly dense and large bulk Y-zeolites (1.5 mm in thickness and 20 mm in diameter) with a significantly large surface area over 700 m2/g were obtained by a short-term hydrothermal hot-pressing (HHP) treatment at 423 K for 2 h, comparable with the Y-zeolite powder.
The Macroeconomics of Labor and Credit Market Imperfections
Authors: Wasmer Etienne , Weil Philippe
Published: September 2004

Credit market imperfections influence the labor market and aggregate economic activity. In turn, macroeconomic factors have an impact on the credit sector. To assess these effects in a tractable general-equilibrium framework, we introduce endogenous search frictions, in the spirit of Peter Diamond (1990), in both credit and labor markets. We demonstrate that credit frictions amplify macroeconomic volatility through a financial accelerator. The magnitude of this general-equilibrium accelerator is proportional to the credit gap, defined as the deviation of actual output from its perfect credit market level. We explore various extensions, notably endogenous wages.
The Politician and the Judge: Accountability in Government
Authors: Maskin Eric , Tirole Jean
Published: September 2004

We build a simple model to capture the major virtues and drawbacks of making public officials accountable (i.e., subjecting them to reelection): On the one hand, accountability allows the public to screen and discipline their officials; on the other, it may induce those officials to pander to public opinion and put too little weight on minority welfare. We study when decision-making powers should be allocated to the public directly (direct democracy), to accountable officials (called “politicians”), or to nonaccountable officials (called “judges”).
A New Measure of Monetary Shocks: Derivation and Implications
Authors: Romer Christina D , Romer David H
Published: September 2004

This paper develops a measure of U.S. monetary policy shocks for the period 1969–1996 that is relatively free of endogenous and anticipatory movements. Quantitative and narrative records are used to infer the Federal Reserve's intentions for the federal funds rate around FOMC meetings. This series is regressed on the Federal Reserve's internal forecasts to derive a measure free of systematic responses to information about future developments. Estimates using the new measure indicate that policy has large, relatively rapid, and statistically significant effects on both output and inflation. The effects are substantially stronger and quicker than those obtained using conventional indicators.
Sunk Investments Lead to Unpredictable Prices
Authors: Mailath George J , Postlewaite Andrew , Samuelson Larry
Published: September 2004

We study transactions that require investments before trading in a competitive market, when forward contracts fixing the transaction price are absent. We show that, despite the market being perfectly competitive and subject to arbitrarily little uncertainty, the inability to jointly determine investment levels and prices may make it impossible for buyers and sellers to predict the prices at which they will trade, leading to inefficient levels of investment and trade.
Desegregation and Black Dropout Rates
Authors: Guryan Jonathan
Published: September 2004

In 1954 the United States Supreme Court ruled that separate schools for black and white children were “inherently unequal.” This paper studies whether the desegregation plans of the next 30 years benefited black and white students in desegregated school districts. Data from the 1970 and 1980 censuses suggest desegregation plans of the 1970's reduced high school dropout rates of blacks by two to three percentage points during this decade. No significant change is observed among whites. The results are robust to controls for family income, parental education, and state- and region-specific trends, as well as to tests for selective migration.
The Opportunity Criterion: Consumer Sovereignty Without the Assumption of Coherent Preferences
Authors: Sugden Robert
Published: September 2004

This paper proposes a formulation of consumer sovereignty, for use in normative economics, which does not presuppose individuals' preferences to be coherent. The fundamental intuition, that opportunity and responsibility have moral value, is formalized as an “opportunity criterion” for assessing resource allocation systems. A model of an exchange economy is presented in which rational arbitrageurs compete to make profits by trading with nonrational consumers. In equilibrium, this economy satisfies the opportunity criterion. One interpretation of this result is that, in a competitive environment, the overall effects of money pumps are benign, even if individuals' preferences are unstable or incoherent.
Inequality Aversion, Efficiency, and Maximin Preferences in Simple Distribution Experiments
Authors: Engelmann Dirk , Strobel Martin
Published: September 2004

We present simple one-shot distribution experiments comparing the relative importance of efficiency concerns, maximin preferences, and inequality aversion, as well as the relative performance of the fairness theories by Gary E Bolton and Axel Ockenfels and by Ernst Fehr and Klaus M. Schmidt. While the Fehr-Schmidt theory performs better in a direct comparison, this appears to be due to being in line with maximin preferences. More importantly, we find that a combination of efficiency concerns, maximin preferences, and selfishness can rationalize most of the data while the Bolton-Ockenfels and Fehr-Schmidt theories are unable to explain important patterns.
Oestrogen: brain ageing, cognition and neuropsychiatric disorder
Authors: Norbury Ray , Craig Michael , Cutter William J. , Whitehead Malcolm , Murphy Declan GM
Published: September 2004

The effects of oestrogen on brain ageing, cognition and neuropsychiatric disorder are an important public health issue, which, despite intensive research, has yet to be resolved. Evidence from basic science demonstrates that oestrogen has multiple protective effects on neurons and neurotransmitter systems. However, the evidence for oestrogen having a clinical role in the treatment and prevention of neuropsychiatric disorders is not well established. Here we review research into the effects of oestrogen on brain maturation and function and discuss the role for oestrogen replacement therapy (ERT) as a therapeutic tool.
Inequality, Segregation, and the Overrepresentation of African Americans in School Suspensions
Authors: Eitle Tamela McNulty , Eitle David James
Published: September 2004

Using school, district, and county data from the State of Florida Department of Education and the U.S. Census, we examine the relationship between school segregation and the overrepresentation of black students among those suspended. We explore two competing hypotheses about the nature of this relationship: (1) an overall racial inequality hypothesis that suggests schools located in districts with relatively high levels of segregation among students also have the largest black suspension imbalances and (2) a resegregation hypothesis that suggests schools situated in relatively highly segregated districts have the lowest rates of black imbalances in suspension. Results from a multilevel analysis indicated that higher levels of school segregation corresponded with lower levels of the black suspension imbalance and provided support for the resegregation hypothesis.
The Role of Identity Salience and Commitment in the Stress Process
Authors: Marcussen Kristen , Ritter Christian , Safron Deborah J.
Published: September 2004

The relationship between identity and stress has been the focus of numerous studies. An assumption of much of this research is that the impact of stress on psychological distress is exacerbated when it threatens identities that are important to an individual's self-definition. In this study we investigate the moderating effect of identity in the stress process. Specifically, we examine whether identity salience and commitment influence the relationship between role-strain and depression, as well as between strain and self-evaluation (i.e., self-esteem and mastery). Using longitudinal data, we find some support that commitment moderates the relationship between strain in the student identity and both mastery and depression. Our findings indicate that the extent to which identity meaning exacerbates the effect of strain on self-evaluation and well-being depends on the type of strain, the particular identity characteristic, and the outcome variable examined.
The Ideal Type of Authority in the United States and Germany
Authors: Schneider Andreas
Published: September 2004

Using affect control theory, an ideal type of authority is developed from the literature identifying three dimensions of meaning. This ideal type is then used to compare U.S. and German subjects. Because their power is legitimated by cultural rules, authorities are positively evaluated despite their ability to coerce. Because it is understood, authorities need not engage in expressive action to demonstrate their power. The affective meaning of role identities reflects their structural meaning, such as authority. Role identities, rated on three-dimensional semantic differential scales of affective meaning, are classified using a K-means clustering algorithm to empirically generate clusters of structural meaning. The cluster discussed here corresponds to the ideal typical authority category of potent, positively evaluated, and not expressive role identities. In the two studies reported here involving more than 1,700 U.S. and German subjects, I find a high degree of cross-cultural agreement on what is classified as authority. However, U.S. and German youth differ significantly in confirming the ideal type of authority. German youth dislike the power potential of authorities more than their U.S. counterparts do.
Kadmium-szennyezés utóhatása a talajra és növényekre egy barna erdőtalajon
Authors: Máthéné Gáspár Gabriella , Szabó Lajos , Anton Attila , Máthé Péter , Orgoványi Balázs
Published: September 2004

Kadmium-szennyezés (270 kg/ha CdSO4) utóhatását vizsgáltuk a talaj Cd-tartalmára, humuszfrakcióira, a talajlégzés intenzitására, tenyészedényben nevelt hat növényfaj növekedésére és a hajtások elemtartalmára. A méréseink alapjául szolgáló barna erdotalajt szabadföldi nehézfém-szennyezéses tartamkísérlet Cd-terhelt és kontrollparcelláinak felso 20 cm-es rétegébol vettük, a terhelés utáni nyolcadik évben a Gyöngyös melletti Taspusztán (Károly Róbert Foiskola kísérleti tere). A kiszárított, kezelésenként homogenizált talajmintákból meghatároztuk a királyvízzel és ammónium-acetát + EDTA-val kioldott elemtartalmat (23 elemre). A légzésintenzitást elektronikus manométerrel 20 másodpercenként rögzített nyomásadatok alapján állapítottuk meg a 70%-ra nedvesített és 30 napig inkubált talajból. A talaj szerves anyagainak meghatározását az ún. két oldószeres eljárással (NaOH és NaF) végeztük.  A Cd-szennyezett és kontrolltalajon hat növényfajjal (retek, repcsény, sárga viola, sóska, laboda, oroszlánszáj) tenyészedény-kísérletet végeztünk. A 60 napig nevelt növények hajtásfejlodését, növekedését és elemtartalmát (salétromsavas roncsolás után) vizsgáltuk. Az elemanalízist minden esetben ICP-vel végeztük. Eredményeinkbol a következo megállapításokat tehetjük.  - A talaj Cd-szennyezése a nyolcadik évben is kimutatható volt a talaj felso rétegében, értéke (2,3 mg/kg) meghaladta az ún. “B-határértéket” (1,0 mg/kg).  - A talaj-mikroorganizmusok légzésintenzitása a szennyezett talajban magasabb volt a kontrollénál. A kadmium légzést serkento hatása visszavezetheto a Cd-kezelt talaj labilis humusztartalmának növekedésére, azaz egy korábbi, magasabb Cd-szintnél valószínusítheto gátlásra.  - A vizsgált hat növényfaj kelése, fejlodése és növekedése a szennyezést nem jelezte. A növényfajok hajtásának különbözo mértékben, de kivétel nélkül szignifikánsan nott a Cd-tartalma, s kisebb-nagyobb mértékben változott az egyéb elemtartalma is. Csökkent a Zn-tartalom (három fajnál megbízhatóan), többnyire nott a Ni-koncentráció, egy fajnál nott, egynél pedig csökkent a Mn-tartalom. A vizsgált növényfajok Cd-tartalma pozitív összefüggést mutatott S- és P-tartalmuk összegével.  - Megállapítható volt, hogy a Cd-szennyezés utóhatása még a szennyezés utáni nyolcadik évben is jelentos, s mind a talaj-mikroorganizmusok muködésében, mind a növények elemfelvételében megmutatkozik.
Indikációs modellek és alkalmazásuk a talajökológiában
Authors: Dombos Miklós , Szalkai Tímea
Published: September 2004

Tanulmányunkban az indikációs módszerek három csoportját tekintettük át:  1. az életközösségek szerkezeti leírása,  2. a korrelációs elemzésekre épülo indikációs módszerek,  3. a muködési, hatás-alapú indikációs módszerek.  A korrelációs indikációs módszerek elterjedtek az ökológiai indikációban, azonban e módszercsalád korlátozottan alkalmazható az ökológiai hatás-tanulmányokban: egyrészt mivel nem arányskálán adja meg az érzékenységet, másrészt, mivel idoben nem alkalmas elore jelezni a várható ökológiai következményeket.  A hatás-alapú módszer módszertanában és felhasználhatóságában is lényegesen eltér az elozoekétol. A hatás-alapú indikációban részletes közvetlen ökológiai kapcsolatok rendszerébol idoben elore jósló modell épül fel, amely egy olyan eszköz a környezeti tervezés számára, mellyel szcenárió- és kockázati elemzéseket is el lehet végezni. Az EEA, illetve más európai léptéku monitoring fejlesztését végzo szervezetek és programok (pl. OECD, 2003) az indikációs eljárást, illetve a talajállapot jellemzésének módszertanát aDPSIRrendszer alapján határozták meg. Ez aDriving forces,Pressures, State,Impact,Responses, azaz a ható tényezok, a terhelések, az állapot, a hatás meghatározása és az adott válaszok együttes kezelését, a modellek szintjén történo integrálását és az intézkedések meghatározását és szabályozását jelenti. Az EU/EEA és az OECD által koordinált munkákban a talaj mezofaunáján alapuló talajökológiai indikáció jelentos szerepet kap, mely vizsgálatokról a Rómában 2003-ban megrendezett OECD konferencia publikációjából ismerkedhetünk meg. E munkákban a korrelációs és a hatás-alapú indikációs eljárásokat részesítik elonyben. Az európai léptéku talajmonitoring rendszer felépítésének tervezésénél, továbbá a hazai talaj-monitoring rendszer fejlesztésénél és harmonizációjánál lényeges elem, hogy a mért paraméterek alkalmazhatóak legyenek adekvát elemzo rendszerekhez.  A jövore nézve tehát mind a felhasználandó értékelo módszerek, mind az azt kiszolgáló adattermelo monitoring rendszerek tekintetében a nemzetközi viszonylatban kompatibilis módszerek fejlesztése lehet a cél.
Kukorica genotípusok vízellátottsága és vízhasznosítása
Authors: Rajkainé Végh Krisztina , Szundy Tamás
Published: September 2004

Erdőmaradványos csernozjom talajon beállított szabadföldi kísérletben három éven át vizsgáltuk hat kukorica genotípus - két hibrid és szülőtörzseik - vízellátottságát és vízhasznosítását. Megállapítottuk, hogy a vizsgált genotípu-sok jelentősen eltérő vízgazdálkodásúak. A hibridek vízfelvételi hatékonyságában és vízhasznosításában eltérő mechanizmusok is szerepet játszanak. Főbb megállapításaink az alábbiak: - A talajnedvesség- és gyökérprofilok eltérnek a különböző genotípusoknál. - Az Mv 444 nagy gyökérsűrűsége a mélyebb talajrétegekben előnyös a felső talajrétegek kiszáradása esetén. - A vízhasznosítási együttható legmagasabb értékeit a két hibridnél mutattuk ki. - Alacsony vízellátottságon egyéb mechanizmusok is közrejátszanak az alkalmazkodásban, úgymint különbségek a növekedési sebességben, tápanyag- igényben és transzspirációban, valamint a biomassza és tápanyag allokációban.
Foszfor-utóhatások erdőmaradványos csernozjom talajon a karbonátosság függvényében
Authors: Árendás Tamás , Bónis Péter , Molnár Dénes , Sarkadi János
Published: September 2004

Martonvásáron, erdomaradványos csernozjom talajon beállított trágyázási tartamkísérlet 28 évének eredményei alapján, a muvelt réteg eltéro mésztartalma szerint elemeztük a vizsgálatokat megelozo 16 évben mutrágyákkal talajba juttatott, de a növények által fel nem vett foszfor utóhatását.  A vizsgálatok kezdetén a meghatározott AL-P2O5-tartalom a közepesen meszes talajokban 92-138, az erosen meszes parcellákon 127-152 mg×kg-1 volt. 12 év után a koncentráció 47-64, illetve 70-83 mg×kg-1-ra csökkent, majd ezeken a szinteken stabilizálódott.  A kumulált termések alapján az eltéro karbonátosság a korábbi PK-kezelés utóhatását tekintve volt a legkifejezettebb, amelynél a kevésbé meszes parcellákon a kontrollhoz viszonyított átlagos évenkénti utóhatás 0,64 t×ha-1-ral volt több, az erosen meszeshez viszonyítva. A négyéves periódusokra bontott kísérlet varianciaanalízisének eredményei szerint az elso három ciklusban a növekvo mésztartalom negatívan, a P-trágyák utóhatása pozitívan és közel azonos mértékben igazolhatóan befolyásolta a termoképességet. A talajban maradt foszfor termésnövelo hatása a negyedik trágyázási ciklustól kezdodoen a termesztett növények átlagában azonban már nem különbözött statisztikailag igazolhatóan az 1958 óta P-trágyázatlan parcellákétól. Az ún. vertikális összehasonlítás módszerét alkalmazva, a relatív termések idobeli változása alapján növényfajonként is elemeztük a P-utóhatásokat. A regresszió analízis alapján elkészített becslések szerint erosen meszes erdomaradványos csernozjom talajon a kukorica termése dikultúrában a termesztés 14., az oszi búza mennyisége a termesztés 23. évét követoen csökkent a P-trágyázatlan kontroll szintjére. Közepesen meszes erdomaradványos csernozjom talajon a kukorica P-reakciója a vizsgálatok 22. évében mérséklodött a kontroll szintjére. Oszi búzában az utóhatás teljes megszunése a relatív termésekhez illesztett logaritmusfüggvény paraméterei alapján a 36. évre prognosztizálható.
The Unilateral Euroisation Debate in Central and Eastern European EU Accession Countries
Authors: Wójcik C. , Backé P.
Published: September 2004

This paper provides an analysis of the economic benefits, costs and risks that a fast unilateral euroisation would have for the Central and Eastern European EU accession countries. In doing so, a comprehensive and broad overview of the euroisation debate is presented. The overall conclusion from the analysis is that, at this stage, the economics of a rapid unilateral euroisation are highly ambiguous and probably even harmful for the accession countries. However, there are good reasons to believe that the cost-benefit balance of full monetary integration will turn positive for some accession countries within a few years if sound macroeconomic policies are retained, the Maastricht criteria are fulfilled and structural reforms are carried on further to underpin the sustainability of convergence.
The Development of Competition Policy in the Ukraine
Authors: Stotyka Y.
Published: September 2004

In 1991 Ukraine became an independent state, abandoned central planning, and started the transformation of its economy. The country inherited a highly monopolised structure of economy from the Soviet Union, therefore demonopolisation and the development of competition have been among the main areas where structural changes were necessary. The present study gives a comprehensive picture of the development of antitrust policy in the Ukraine from 1992 to 2002 through an assessment of evolving competition policy and examination of the policy's implementation. On the one hand, the development of competition policy in the Ukraine included the establishment of rules and appropriate procedures, as well as the creation of a proper institutional framework. On the other hand, the lack of a unified state approach to the reformation of the economy in general and to the problems of the development of competition in particular could be observed. The actions of different state organs were not synchronised, and competition policy in the Ukraine failed to become the main element of the economic policy setup.
Hungary's Competitiveness in an International Comparison - A Supply-side Approach
Authors: Losoncz M.
Published: September 2004

The paper analyses Hungary's competitiveness in international comparison by focusing on the supply-side factors determining competitiveness. Although it attaches outstanding importance to the business-friendly general economic environment mainly in terms of the transition to the market economy and attracting foreign direct investments, the interrelationship among labour productivity, labour costs and nominal and real exchange rates are in its focal point. Its main conclusion is that it is labour productivity which determines international competitiveness in the long run. However, appropriate economic-policy measures are required to prevent the erosion of relative international competitiveness by increasing labour costs and the real appreciation of the national currency.
Conference Reports
Authors: Kapás Judit , Komáromi György , Czeglédi Pál , Jankovics László
Published: September 2004

Institutions and Change (ISNIE Conference)  - The International Society for New Institutional Economics (ISNIE) held its 7th annual conference in Budapest on 11-13 September 2003; The Link between Diversity and Development Paths (EACES Conference) - International conference on the Institutional and Policy Diversity - Its Role in Economic Development on 3-4 November 2003 in Debrecen, Hungary
Book Reviews
Authors: Halilov Merdan , Kudrna Zdenek , Kapás Judit
Published: September 2004

[Book reviews] Winiecki, J.: Transition Economies and Foreign Trade. London and New York: Routledge, 2002, 150 pp.; Olson, M.: Power and Prosperity: Outgrowing Communist and Capitalist Dictatorship. New York: Basic Books, 2000, 233 pp.; Krizsán, A. - Zentai, V. (eds): Reshaping Globalization - Multilateral Dialogues and New Initiatives. Budapest: Central European University Press, 2003, 327 pp.
Third coronary artery in monkey heart
Authors: Nikolić Valentina , Teofilovski-Parapid Gordana , Stanković Gordana , Parapid Biljana , Malobabić S. , Stojić V.
Published: September 2004

The objective of the present study was to determine the effects of follistatin addition on myostatin and follistatin gene expression patterns in C2C12 muscle cells. C2C12 cells were administered with 100 ng/ml recombinant human (rh) follistatin in Dulbecco's modified Eagle medium (DMEM) containing 10% fetal bovine serum (FBS), 4 mM glutamine and antibiotics daily for three days. Rh follistatin was not added in the control wells. Follistatin and myostatin gene cDNAs were synthesised by reverse transcriptase polymerase chain reaction (RT-PCR).The time course of follistatin gene expression pattern was similar in both the control and the follistatin-treated group. Myostatin mRNA level significantly increased in the follistatin-treated group after 24 h of culture (Fig. 3, P < 0.01). Amounts then sharply decreased (Fig. 3, P < 0.01) at 48 h of culture, whereas there was no significant difference between the control and the follistatin-treated group at 72 h of culture. Our results demonstrated that myostatin and follistatin mRNA were expressed in C2C12 cells and rh follistatin changed the myostatin expression pattern.
Thyroid hormones (th) and 5'-monodeiodinase (5'-md) activity in goat's milk from the early, mid- and late lactation period
Authors: Ślebodziński A. B. , Twardon J.
Published: September 2004

The physiological significance of thyroid hormones (TH) present in colostrum and milk is still under consideration. The present study was aimed at determining milk thyroxine (T4) and triiodothyronine (T3) levels in three lactation phases (early, mid- and late) of the goat, and to measure activity of the milk 5'-deiodinase (5'-MD) enzyme responsible for the intramammary conversion of pro-hormone T4 to its metabolically highly active form T3. Thirty-two milk goats (Polish White breed) fed a standard diet were used for milk sampling. The highest TH levels in mammary secretion were recorded during the first 2-3 days post partum. Then the hormone levels decreased, and by about Day 7 fluctuated around the overall mean for the early-lactation phase (Days 1 to 24 of lactation), recording 0.134 ± 0.059 µg T4 and 150.8 ± 2.80 ng T3 in 100 ml of the milk. Such T4 concentrations appeared to be comparable to those in the rabbit and human, whereas the concentration of T3 was higher than in the cow, pig and mare's milk. Milk 5'-MD activity was higher (P < 0.01) during early and late lactation, compared to the mid-lactation phase. It coincided with low T4 and high T3 milk levels during early lactation, and with high milk T4 and low T3 concentrations during late lactation. The quantity of T4 and T3 available to newborn kids in milk suggests that TH ingested with the colostrum may have a physiological role during the early postnatal life of suckling goats.
Genetic variation within and relationships among five subpopulations of Slovak Thoroughbred
Authors: Šátková-Jakabová Daniela , Trandžík J. , Hudecová-Kvasňáková Ľudmila , Hegedüšová-Zetochová Erika , Bugarský A. , Buleca Jr. J. , Zöldág L. , Jakab F. , Fľak P.
Published: September 2004

Genetic variation at six microsatellite loci was analysed for five Thoroughbred subpopulations to determine the magnitude of genetic differentiation and the genetic relationships among the subpopulations. Significant deviations from Hardy-Weinberg equilibrium were shown for a number of locus-population combinations, with all subpopulations. The genetic diversities and relationships of five Thoroughbred subpopulations were evaluated using six microsatellites recommended by the International Society of Animal Genetics (ISAG). The allele frequencies, the effective numbers of alleles, and the observed and expected heterozygosities were calculated. POPGENE v. 1.31 (Yeh et al., 1997) was used to test for deviations from the Hardy-Weinberg (H-W) equilibrium and to assign FISestimates (Weir, 1990). The utility of microsatellites for evaluating genetic diversity of horses is discussed.
Effectiveness of different adjuvants in stimulating Dichelobacter nodosus antibody in sheep vaccinated against ovine footrot
Authors: Martín-Palomino P. , Píriz S. , Jiménez Ruth , Serrano F. J. , Vadillo S.
Published: September 2004

This research consists of an evaluation of the effectiveness of different substances administered as adjuvants in the stimulation of humoral immune response induced by the vaccine composed of strains A1, A2 and C of Dichelobacter nodosus. To do this, a total of 120 Merino sheep were vaccinated and revaccinated. These sheep were selected from a farm located in the region of Extremadura (Spain), and they were divided into 12 groups of 10 animals each. An additional group with 10 sheep was used as control. The immune response (titre of antibodies) was determined by agglutination tests and ELISA. The most pronounced immune response was obtained by the use of Freund's incomplete adjuvant and aluminium hydroxide as adjuvants.
Study of programmed cell death in bovine herpesvirus 1 infected mdbk cells and the possible role of nitric oxide in this process
Authors: Yazici Zafer , Baskin Yasemin , Baskin H. , Gecer Ozlem , Hakki Bahar I. , Özkul Aykut
Published: September 2004

Bovine herpesvirus 1 (BHV-1) is the aetiological agent of many disease types and may predispose infected animals, possibly through immunosuppression, to secondary bacterial infections. Immunosuppression may directly be associated with the induction of programmed cell death (PCD) in some virus-infected cells. Nitric oxide (NO) has an important mediating role against fungal, bacterial, protozoal, viral pathogens and tumours. BHV-1 induced apoptosis between 0.5-3 h postinfection (PI) in MDBK cells; however, between 3 and 6 h PI the PCD response was found to be decreased. It was interesting to see that BHV-1 inhibited staurosporin-induced PCD after 1 h. These results showed similarities with those obtained from herpes simplex type 1 infections in human epithelial cells. PCD response decreased 1 h following caspase-3 inhibitor applications, whereas NO response increased 3 h following infection in the presence of caspase-8 and -9 inhibitory peptides. In conclusion, BHV-1 inhibited the staurosporin-induced apoptotic response and also the NO response. We propose that this inhibition is caspase-3 dependent.