bluuebunny/crossref_metadata_2025 huggingface dataset:
An Adapted Ring Shear Apparatus for Testing Partly Saturated Soils in the High Suction Range
Authors: Merchán Vladimir , Romero Enrique , Vaunat Jean
Published: July 2011

The paper presents an adapted experimental setup to study the residual shear strength properties of clays under unsaturated state conditions. This issue is of geotechnical concern in stability analysis of slopes in fissured rocks with unsaturated clayey fills and also, in a more fundamental way, as an indicator of microstructural changes of clays undergoing drying paths. To this end, a commercial ring shear apparatus (Bromhead type) was instrumented and adapted to control total suction in a wide range by using vapor transfer technique. In addition, by using simulation-aided techniques, the time evolution of suction at local state and axial deformation was studied to overcome the experimental difficulty associated with the determination of the suction equalization time. The simulated equalization period agreed well with the experimental information based on a mechanical stabilization criterion (time required to attain vertical strain rates lower than 0.1%/day). Relevant test results showing the main capabilities of the adapted apparatus are presented, which bring up the important changes observed in residual friction angle when testing a clayey soil at different hydraulic states (total suctions ranging from nearly 0 up to 140 MPa).
Effects of immunizing ewes against bone morphogenetic protein 15 on their responses to exogenous gonadotrophins to induce multiple ovulations
Authors: Juengel Jennifer L , Quirke Laurel D , Lun Stan , Heath Derek A , Johnstone Peter D , McNatty Kenneth P
Published: July 2011

Sheep with a heterozygous inactivating mutation in the bone morphogenetic protein 15 (BMP15) gene experience an increased ovulation rate during either a natural oestrous cycle or a cycle in which exogenous FSH and eCG (gonadotrophins) are given to induce multiple ovulations. The primary aim of these studies was to determine whether ewes immunised against BMP15 would also show an improved superovulation rate following exogenous gonadotrophin treatment. A secondary aim was to determine the effects of BMP15 immunisation on ovarian follicular characteristics. In most ewes (i.e. >75%) immunised with a BMP15-keyhole limpet haemocyanin peptide in an oil-based adjuvant in order to completely neutralise BMP15 bioactivity, there was no superovulation response to exogenous gonadotrophins. In ewes treated with exogenous gonadotrophins following a BMP15-BSA peptide immunisation in a water-based adjuvant to partially neutralise BMP15 bioactivity, the ovulation rate response was similar to the control superovulation treatment groups. Characterisation of follicular function revealed that the water-based BMP15-immunised animals had fewer non-atretic follicles 2.5–3.5 or >4.5 mm in diameter compared with controls. Basal concentrations of cAMP were higher in granulosa cells from animals immunised against BMP15 than control animals. There were no significant differences in the concentrations of cAMP between granulosa cells from BMP15- and control-immunised animals when given FSH or hCG, although there were differences in the proportions of follicles in different size classes that responded to FSH or hCG. Thus, immunisation against BMP15 may have been causing premature luteinisation and thereby limiting the numbers of follicles recruited for ovulation following treatment with exogenous gonadotrophins.
Joint Inference of Population Assignment and Demographic History
Authors: Choi Sang Chul , Hey Jody
Published: July 2011

A new approach to assigning individuals to populations using genetic data is described. Most existing methods work by maximizing Hardy–Weinberg and linkage equilibrium within populations, neither of which will apply for many demographic histories. By including a demographic model, within a likelihood framework based on coalescent theory, we can jointly study demographic history and population assignment. Genealogies and population assignments are sampled from a posterior distribution using a general isolation-with-migration model for multiple populations. A measure of partition distance between assignments facilitates not only the summary of a posterior sample of assignments, but also the estimation of the posterior density for the demographic history. It is shown that joint estimates of assignment and demographic history are possible, including estimation of population phylogeny for samples from three populations. The new method is compared to results of a widely used assignment method, using simulated and published empirical data sets.
A Conserved Long Noncoding RNA Affects Sleep Behavior inDrosophila
Authors: Soshnev Alexey A , Ishimoto Hiroshi , McAllister Bryant F , Li Xingguo , Wehling Misty D , Kitamoto Toshihiro , Geyer Pamela K
Published: July 2011

Metazoan genomes encode an abundant collection of mRNA-like, long noncoding (lnc)RNAs. Although lncRNAs greatly expand the transcriptional repertoire, we have a limited understanding of how these RNAs contribute to developmental regulation. Here, we investigate the function of the Drosophila lncRNA called yellow-achaete intergenic  RNA (yar). Comparative sequence analyses show that the yar gene is conserved in Drosophila species representing 40–60 million years of evolution, with one of the conserved sequence motifs encompassing the yar promoter. Further, the timing of yar expression in Drosophila virilis parallels that in D. melanogaster, suggesting that transcriptional regulation of yar is conserved. The function of yar was defined by generating null alleles. Flies lacking yar RNAs are viable and show no overt morphological defects, consistent with maintained transcriptional regulation of the adjacent yellow (y) and achaete (ac) genes. The location of yar within a neural gene cluster led to the investigation of effects of yar in behavioral assays. These studies demonstrated that loss of yar alters sleep regulation in the context of a normal circadian rhythm. Nighttime sleep was reduced and fragmented, with yar mutants displaying diminished sleep rebound following sleep deprivation. Importantly, these defects were rescued by a yar transgene. These data provide the first example of a lncRNA gene involved in Drosophila sleep regulation. We find that yar is a cytoplasmic lncRNA, suggesting that yar may regulate sleep by affecting stabilization or translational regulation of mRNAs. Such functions of lncRNAs may extend to vertebrates, as lncRNAs are abundant in neural tissues.
emb-1 Encodes the APC16 Subunit of the Caenorhabditis elegans Anaphase-Promoting Complex
Authors: Shakes Diane C , Allen Anna K , Albert Kelsey M , Golden Andy
Published: July 2011

In the nematode Caenorhabditis elegans, temperature-sensitive mutants of emb-1 arrest as one-cell embryos in metaphase of meiosis I in a manner that is indistinguishable from embryos that have been depleted of known subunits of the anaphase-promoting complex or cyclosome (APC/C). Here we show that the emb-1 phenotype is enhanced in double mutant combinations with known APC/C subunits and suppressed in double mutant combinations with known APC/C suppressors. In addition to its meiotic function, emb-1 is required for mitotic proliferation of the germline. These studies reveal that emb-1 encodes K10D2.4, a homolog of the small, recently discovered APC/C subunit, APC16.
Simulations of cyclic shearing of sand at low effective stress
Authors: SANDS C.M. , CHANDLER H.W.
Published: July 2011

This paper presents a very simple soil model of reduced dimensionality, that, using only two adjustable parameters, captures all the essential features of a set of six undrained cyclic torsional shear tests carried out on Toyoura sand by Oka and co-workers. The same values for all the model parameters (all but two of which are obtained from published data) are used for all six tests and very good agreement between the experimental test results and the simulations is achieved. Simulations of drained tests are also presented. The model uses a parameter that stores the recent strain history of the soil and that the authors show can be related to Houlsby's anisotropy parameter. The relationship between the volume and shear strain increments contains two terms. The first term simulates continual compaction while the second can predict additional compaction or dilatancy, depending on the direction of the shear strain increment. These two terms cancel each other out during continuous deformation at the critical state, but reinforce each other on reversal to predict the rapid densification observed experimentally.
Effect of shaft on resistance of a ball penetrometer
Authors: ZHOU H. , RANDOLPH M.F.
Published: July 2011

The influence of the shaft on the resistance of a ball penetrometer was examined using a large deformation finite-element approach. A range of ball–shaft diameter ratios between infinitely large (no shaft) to 1 were examined in terms of resistance during monotonic penetration and extraction. It was found that the steady-state resistance decreased with decreasing ball–shaft diameter ratio, and that greater displacement (as a proportion of the shaft diameter) was required to reach a steady state. The finite-element results were matched closely using an upper bound approach, treating the shaft and outer part of the ball separately. It was also found that the rigidity index of the soil affected the penetration resistance of the shafted ball, but the influence was much less than for a cone penetrometer, being essentially proportional to the shaft–ball area ratio. Finally cyclic penetration and extraction tests were modelled comparing results for the no-shaft ball and a shafted ball with ball–shaft diameter ratios of 2 and 3. The presence of the shaft was found to have minimal influence on the resistance and cyclic degradation curves, although at the later stage of cycling the penetration resistance becomes greater than the extraction resistance. The corresponding resistance ratio of extraction to penetration for each cycle reduces with decreasing ball–shaft diameter ratio and increasing soil sensitivity. In terms of the change in mean total stress, however, the presence of the shaft introduces a pronounced gradient with respect to displacement during cyclic penetration and extraction, while increasing the changes in mean stress significantly during initial penetration.
Sand on Demand: A Laboratory Investigation on Improving Productivity in Horizontal Wells Under Heavy-Oil Primary Production
Authors: Meza-Díaz Brígida , Sawatzky Ronald , Kuru Ergun , Oldakowski Kaz
Published: July 2011

The cold-production recovery process, also known as cold heavy-oil production with sand (CHOPS), is a method for enhancing primary heavy-oil production by aggressively producing sand (massively and persistently). It is a successful commercial recovery process in western Canada using vertical (or slanted or deviated) wells. Applications of cold-production technology with aggressive sand production in horizontal wells, however, have not met with commercial success.

This paper presents the results of experiments performed to assess the feasibility of applying cold heavy-oil production with horizontal wells using less-aggressive (i.e., controlled) sand-production strategies. Specifically, the effects of slot size, confining stress, fluid velocity, and sand-grain sorting on sand production have been investigated.

Preliminary results indicate that slot-size selection is critical for establishing "sand on demand." For proper slot-size selection, it is essential to know the grain-size distribution of the sand—in particular, attributes such as the size of the coarsest fraction of the sand and the sorting (uniformity coefficient) of the sand. For example, it was observed in the sand-production experiments that the critical pressure gradient for maintaining continuous sand production is much lower for well-sorted sands (narrow size distribution) than for poorly sorted sands (wide size distribution). Ultimately, poorly sorted sands may require criteria different from those for well-sorted sands for slot-size selection.

Flow rates are also crucial for managing sand production because a critical pressure gradient is required for initiating sand production and maintaining continuous sand production. The critical pressure gradient decreases as the slot width or confining pressure increases. Large permeability increases were observed in the sand-production region. Persistent sand production led to the growth of a channel and/or the presence of a dilated zone that had an elliptic shape.
Method for Determining the Bioconcentration Factor of Linear Alcohol Ethoxylates
Authors: Fraser Greig
Published: July 2011

Determination of the potential of surfactants to bioaccumulate in marine species has long been problematic in the chemical-hazard and environmental-impact assessments performed for offshore operations. Recently, this issue has become increasingly significant because regulators have invoked the precautionary principle and assume that all surfactants with molecular weight of less than 700 will bioaccumulate, leading to an increased number of oilfield-chemical products labeled as environmentally unacceptable.

The relationship between the bioconcentration factor (BCF) of nonsurfactant substances and their corresponding octanol/water partition coefficient (Pow) value is well studied, and many relationships have been developed. Log Pow is generally, therefore, used as a surrogate for the BCF of nonsurfactant substances.

This methodology cannot be applied directly to surfactants because the formal log Pow of such substances is difficult, if not impossible, to determine accurately. By their very nature, surfactants tend to form emulsions or accumulate at interfaces; therefore, the standard OECD 107 [Test No. 107: Partition Coefficient (n-octanol /water): Shake Flask Method 1995] or OECD 117 [Test No. 117: Partition Coefficient (n-octanol /water), HPLC Method 2004] protocols cannot be used.

This paper describes a simple method for accurately determining the BCF of linear alcohol ethoxylates (LAEs), an important group of nonionic surfactants that are commonly used in the oil industry. Quantitative structure-activity relationship (QSAR) software built on fragment contributions averaged over a large number of mostly nonsurfactant substances is initially used to calculate a "log pseudoPow" value. This hydrophobic parameter is then correlated to BCF values determined in flow-through experiments, with excellent agreement (R2 > 0.99). The method involves no animal testing, is inexpensive to set up and perform, is accessible to all, is quick and easy to use and verify, and gives clear output.
Laboratory Study of Diversion Using Polymer-Based In-Situ-Gelled Acids
Authors: Gomaa A.M. M , Mahmoud M.A.. A. , Nasr-El-Din H.A.. A.
Published: July 2011

In-situ-gelled acids that are based on polymers have been used in the field for several years and were the subject of many laboratory studies. These acids are used in stages to block the treated zone and force the next regular-acid stages to the untreated zones. An extensive literature survey reveals that there are conflicting opinions about using these acids. On one hand, these acids were used in the field, with mixed results. On the other hand, recent laboratory work indicated that these acids can cause damage under certain conditions.

The ability of polymer-based in-situ-gelled acids to divert regular acids was studied using a parallel-coreflood setup. The sequence of the injection involved in-situ-gelled acid at 5 wt% hydrochloric acid (HCl) stage followed by regular acid at 15 wt% HCl until acid breakthrough. Experimental results show that flow was initially distributed between the two cores according to the preacid permeability ratio. Permeability grew slightly faster in the higher-permeability core until breakthrough occurred. Therefore, diversion was needed for all acid treatments. At an injection rate of 1 cm3/min, in-situ-gelled acid plugged the two cores. For low permeability contrast (1:2), polymer was able to divert the acid, with permeability enhancement in both cores.

For high permeability contrast (1:20 up to 1:25), in-situ-gelled acid was able to divert the acid only at an injection rate less than 10 cm3/min. However, at higher injection rates, in-situ-gelled acid was not able to build enough pressure to force the regular acid into the low-permeability core. Increasing the injection rate reduced the viscosity of the in-situ-gelled acid. Therefore, acid-injection rate should be determined on the basis of the expected fluid viscosity in the formation. The results obtained can be used to design acid treatments in carbonate reservoirs better.
Methods for Enhancing Far-Field Complexity in Fracturing Operations
Authors: East Loyd , Soliman M.Y.. Y. , Augustine Jody
Published: July 2011

For decades, the oil industry has struggled to overcome nearwellbore-fracture complexity during fracturing treatments, particularly in low-permeability, naturally fractured hard-rock reservoirs. A number of techniques have been created to diagnose and remediate these conditions to enable the extension of created fractures and successful placement of proppant deep in the reservoir. Microseismic-fracture-mapping (MSFM) technology has revealed the creation of far-field complex fracture networks in hard-rock reservoirs during fracture extension. This revelation offers the opportunity to hydraulically connect to a much larger volume of rock, provided that appropriate treatment techniques are applied to ensure the fracture network is adequately connected to the main fracture. Additionally, techniques have been developed and can be applied during the fracture treatments to facilitate and enhance the fracture-network creation. Net fracture-extension pressure analysis combined with real-time MSFM allows for identification of the degree of fracturing-network creation and provides a decisionmaking tool for engineers to modify treatment schedules or apply complexity-enhancing methods on the fly on the basis of desired treatment objectives and rock responses to the fracture treatment.

This new approach to fracture stimulation requires a new focus on rock mechanics that includes defining the brittleness of the rock matrix, determining the existence and magnitude of the principal-stress anisotropy, designing the optimum spacing between fractures, and defining the optimum fracture-treatment parameters. Once the completion design is implemented, the designed treatment parameters can be adjusted in real time to meet the objectives of the completion on the basis of actual rock responses to the treatment. These rock responses are measured in real time using net fracture-extension pressure and MSFM diagnostics. Adjustments made to the fracture treatment are varied and include treatment-rate adjustments, proppant concentration, proppant-slug placement, diversion techniques to ensure opening of natural fractures, viscous-fluid spacers, acid spacers, and incremental stop/start pumping schedules. The proppant-concentration adjustments are enabled for immediate downhole changes through a unique coiled-tubing (CT) fracturing process that incorporates liquid/sand concentrate slurries.

Examples of actual completion designs of these applications are discussed.
Optimum Injection Rate of A New Chelate That Can Be Used To Stimulate Carbonate Reservoirs
Authors: Mahmoud M.A.. A. , Nasr-El-Din H.A.. A. , De Wolf C.A.. A. , LePage J.N.. N.
Published: July 2011

Different chelating agents were used as alternatives for hydrochloric acid (HCl) in matrix acidizing to create wormholes in carbonate formations. Previous studies demonstrated the use of ethylenediaminetetraacetic acid (EDTA), hydroxy ethylenediaminetriacetic (HEDTA), and glutamic acid-N,N-diacetic acid (GLDA) as standalone stimulation fluids to stimulate carbonate reservoirs. The main problem of using EDTA and HEDTA is their low bio-degradability.

GLDA was introduced as a standalone stimulation fluid for deep carbonate reservoirs where HCl can cause corrosion and face dissolution problems. In this study, calcite cores 1.5 in. in diameter and 6 or 20 in. in length were used to determine the optimum conditions where the GLDA can break through the core and form wormholes. GLDA solutions with pH values of 1.7, 3, and 3.8 were used. The optimum conditions of injection rate and pH were determined using coreflood experiments. Damköhler number was determined using the wormhole length and diameter from the CT scan 3D and 2D images. GLDA was compared with chelates that are used in the oil industry such as EDTA and HEDTA. GLDA also was used to stimulate parallel cores with different permeability ratios (up to 6.25).

GLDA was found to be very effective in creating wormholes at pH = 1.7, 3, and 3.8; at different injection rates; and at temperatures up to 300°F. Increasing the temperature increased the reaction rate and less volume of GLDA was required to break through the core and form wormholes. Unlike HCl, in GLDA there was no face dissolution or washout in the cores even at low injection rates (0.5 cm3/min). An optimum injection rate and Damköhler number were found at which the pore volume (PV) required to create wormholes was the minimum. GLDA at pH 1.7 and 3 created wormholes with a small number of PV (at 1 cm3/min, GLDA at pH 1.7 required 1.5 PV at 300°F, and at pH 3 it required 1.8 PV). Compared with acetic acid, the volume of GLDA at pH 3 required to create wormholes was less than that required with acetic acid at the same conditions. GLDA was found to be effective in stimulating parallel cores up to 6.25 permeability contrast (final permeability/initial permeability).
New Perspective on Gas-Well Liquid Loading and Unloading
Authors: Veeken C.A.M.. A.M. , Belfroid S.P.C.. P.C.
Published: July 2011

This paper discusses the multiphase-flow mechanism responsible for gas-well liquid loading. It shows that the conventional idea of droplet-flow reversal (Turner et al. 1969) does not fully describe reality and that liquid-loading observations appear more compatible with film-flow reversal. This paper subsequently explores how film-flow reversal changed views on existing gas-well liquidunloading techniques such as continuous foam injection, and it discusses new methods of gas-well deliquefication that specifically aim to delay film-flow reversal. The benefits of different types of tubing-wall modification have been evaluated through small-scale laboratory testing. Most promising, hydrophobic coating of tubing reduces the gas rate below which liquid loading occurs by approximately 50%. The benefits of hydrophobic coating are translated to representative field conditions.
Stochastic Analysis of Resource Plays: Maximizing Portfolio Value and Mitigating Risks
Authors: Allan Paul D.
Published: July 2011

This paper outlines a method for applying stochastic representations of key macroeconomic parameters and risks in evaluating the portfolio value of resource plays. Stochastic pricing, costs forecasts, and regulatory uncertainties are often neglected or are applied improperly when evaluating what are typically considered to be low-risk resource opportunities. Portfolio allocation and project-development timing may be critically dependent upon these macroeconomic variables, particularly given the long production life and operationally intensive nature of many resource opportunities. The techniques described in this paper will allow corporate planners and exploration-and-production (E&P) executives to better leverage their opportunity inventory and ensure that resource-play development plans are in alignment with stochastic pricing or other macroeconomic forecasts. A model of a typical E&P portfolio with numerous resource plays will be used to demonstrate the basic methodologies and the insights made possible through application of these techniques. This will include analysis of leasing options, pilot-project evaluation, development-timing and -pacing options, and portfolio balance under various macroeconomic conditions. The characteristics of project-level analysis will be contrasted to the decisions and insights made possible through a holistic portfolio-based approach.
Net CO2 Stored in North American EOR Projects
Authors: Faltinson John E. , Gunter Bill
Published: July 2011

One promising method for reducing carbon dioxide (CO2) emissions when storing CO2 in oil reservoirs is CO2 enhanced oil recovery (EOR). In order to make a significant contribution to mitigating climate change from emissions of greenhouse gases (GHGs), CO2 EOR must actually reduce CO2 emissions by storing net positive volumes of CO2. This requires that CO2-EOR schemes store more CO2 in the subsurface than the execution of the project emits (net positive storage of CO2). Fugitive emissions associated with CO2 EOR primarily include the burning of fossil fuels (fuel gas) to power CO2-injection compressors and the on-site consumption of electric power, which results in CO2 emissions off site, where the power was generated. Evaluating the effectiveness of CO2 EOR in reducing CO2 emissions must be conducted in an unbiased way in which only relevant fugitive emissions that are directly connected with the CO2-EOR project are deducted. It has been suggested that fugitive emissions from downstream oil refining and consumption of the transportation products should be deducted from the net CO2 stored by CO2-EOR projects. This presumes that these emissions (refining and consumption) are incremental to world aggregate oil-consumption emissions and would not occur if the EOR project was not executed. World oil production is determined by world oil demand and if CO2-EOR projects were not undertaken, some other source of oil would step forward and fill the gap. Therefore, executing CO2-EOR projects will not result in incremental aggregate refining and consumption emissions. When downstream-refining and product-consumption fugitive emissions are excluded from the calculation of project-life-cycle CO2-EOR storage, it is clear that CO2 EOR does result in net positive CO2 storage.
Modeling the Application of Scale-Inhibitor-Squeeze-Retention-Enhancing Additives
Authors: Vazquez O.. , Thanasutives P.. , Eliasson C.. , Fleming N.. , Mackay E..
Published: July 2011

The most common method for preventing scale formation is by applying a scale-inhibitor (SI) squeeze treatment. In this process, an SI solution is injected down a producer well into the near-wellbore formation. In the last few years, several publications have presented experimental results, field data, and treatment methods showing enhanced squeeze lifetime because of the use of squeeze enhancers.

The main purpose of this paper is to model the effect of SI-retention-enhancing additives. These additives are normally deployed in reservoirs where the SI shows poor retention in the formation matrix in order to reduce well interventions. In the last few years, a number of techniques to enhance the SI retention have been reported in the literature, such as precipitation squeezes using calcium and/or pH-increasing additives, use of an additive package that enhances SI adsorption by crosslinking, and the injection of nondamaging concentrations of kaolinite, calcium carbonate, and organosilane (a solids-fixation agent). The effect of the SI-retention enhancer is modeled as a function of the adsorption level of the additive. A sensitivity study is then presented on the effect of deploying the additive in the different stages; normally, they are deployed in the preflush stage. However, the aim of this paper is to investigate how the treatment could be optimized to achieve the longest squeeze lifetime with a fixed amount of additive. An example of modeling a specific field treatment injecting organosi-lane is included. The results are compared with the field return profiles and clearly demonstrate the value such modeling can bring to the interpretation and design of field squeezes.
Moving the Energy Business From Smart to Genius by Building Corporate IQ
Authors: Weijermars Ruud
Published: July 2011

Moving the energy business from smart asset developers to genius organizations by building corporate intelligence quotient (IQ) is advocated in this study. A company's overall effectiveness in creating primary business value from the available knowledge resources (internally and externally) can be expressed as a corporate IQ score in the framework defined here, using a new questionnaire comprising 140 questions. This questionnaire has now been applied to seven energy companies: five oil operators, one service company, and one natural-gas transmission-service operator. The sample groups are still small, but an interesting pattern emerges that confirms the general notion that internationally operating companies are best at developing organizational intelligence. Their higher corporate IQ is essential to enable them to operate effectively in a highly competitive market. The new data reported here may provide useful insight for national oil companies (NOCs) that wish to improve their organizational intelligence if required by an ambition to internationalize their operations. Companies that excel at organizational learning are better prepared to outperform their competitors. International oil companies (IOCs) also can strive to further the enhancement of their corporate IQ by use of the periodic assessments and interventions outlined in this study.
Livestock Mandatory Price Reporting: A Literature Review and Synthesis of Related Market Information Research
Authors: Koontz Stephen R , Ward Clement E
Published: July 2011

Congress passed into law the Livestock Mandatory Reporting Act in 1999 and a mandatory pricing reporting system for livestock and meat began in 2001. The implementation was problematic. It is also difficult to find any research prior to the legislation that demonstrated inadequacies in the voluntary price reporting system that had been in existence since the Agricultural Marketing Act of 1946. Thus, there is little evidence upon which to evaluate the new system. Available research suggests mandatory price reporting increased transparency and information at the national level and across cash and non-cash market choices, reduced price information in regional markets, and increased spatial and vertical market integration. Research shows diverse opinions on the success of the new system. Research also shows the potential for retail meat scanner data to significantly improve the accuracy of reported retail meat prices. Related research suggests clear benefits of the new system will be hard to measure. A primary conclusion from the literature is that benefits were unforeseen and unintended consequences were large. And that continued cost/benefit oriented research of the policy and legislation would be useful.
The growth of maize seedlings as function of free energy and redox potential
Authors: Dragicevic Vesna , Sredojevic Slobodanka , Spasic Mihajlo
Published: July 2011

The difference in the growth of maize seedlings originating from seeds
injured by accelerated ageing, as well as those altered by restoring with low
2,4-D (2,4-dichlorophenoxyacetic acid) concentrations was examined, from the
point of view of free energy and redox potential. The ageing decreased
germination ability, the seedling growth and free energy, with no remarkable
influence on the redox capacity. Meanwhile, the 2,4-D treatment increased the
germination percentage and the seedling growth, by better energy utilisation,
with shifting of the redox balance to a reducing environment. From this point
of view, the free energy and the redox potential are useful tools for the
determination of biological vitality.
Palynomorphological study of primrose (Primula vulgaris Huds.) grown in natural reserve Obedska bara (Serbia)
Authors: Macukanovic-Jocic Marina , Rancic Dragana , Dajic-Stevanovic Zora
Published: July 2011

The pollen morphology of primrose (Primula vulgaris, fam. Primulaceae) has
been investigated using light and scanning electron microscopy to contribute
to melissopalynological studies of honeys originating from the native
apiflora. Palynomorphological investigation included the examination of
pollen symmetry, polarity, ornamentation, aperturation, shape and size. The
pollen grains are isopolar, radially symmetric and shed as monads. The exine
ornamentation is reticulate. Analysis of pollen morphometric characteristics
revealed that grains are small to medium size and prolate in shape. Given the
aperturation, the number of colpi was mostly variable among individuals with
a different type of flower ranging from 6 to 9.
Selective breeding programme of common carp (Cyprinus carpio L.) in Serbia: Preliminary results
Authors: Spasic Milan , Poleksic Vesna , Stankovic Marko , Dulic Zorka , Raskovic Bozidar , Zivic Ivana , Ciric Milos , Relic Renata , Vukojevic Dalibor , Boskovic Dejan , Markovic Zoran
Published: July 2011

The aim of this study was to estimate heritability and genetic correlations
between weight, length and height of common carp in Serbia (Cyprinus carpio
L.) during 3-year growth period. The 50 families of common carp were produced
in 2007 and used for the estimation of genetic parameters. The fish were
measured at tagging for weight, length and height (W0, L0, H0), then during
the first autumn (W1, L1, H1) and during the second autumn (W2, L2, H2).
Based on univariate models heritability estimates were high for all traits
(0.39, 0.34 and 0.45 for W1, L1 and H1, respectively) and also for the second
production year (0.49, 0.47 and 0.44 for W2, L2 and H2, respectively). The
genetic correlations were estimated using multivariate models and they were
high between W1 and L1 and H1 (0.81 ? 0.06 and 0.91 ? 0.03 for L1 and H1,
respectively), while between H1 and L1 were moderately correlated (0.54 ?
0.12). In the second production year genetic correlations were also high,
between W2 and L2 and H2 (0.64 ? 0.09 and 0.74 ? 0.06, respectively), while
between length and height they were lower (0.24 ? 0.15). Based on the current
results improving growth rate of common carp through genetic selection is
expected to be effective.
Capillariosis in breeder discus (Symphysodon aequifasciatus) in Iran
Authors: Rahmati-Holasoo Hooman , Mousavi Ebrahimzadeh , Soltani Mehdi , Hosseini Seyedhossein , Ghadam Masoomeh , Samani Reza
Published: July 2011

The global ornamental fish trade is a rapidly growing industry. Cultivation
and propagation of ornamental fishes have been increasing in the last 20
years in Iran. Discus (Symphysodon aequifasciatus) from Cichlidae is one of
the most popular and expensive aquarium fish. In the past few years farming
of this fish has been well developed in Iran. Two breeder discus fish
(Symphysodon aequifasciatus) from two different propagation centres (with
high mortality) with signs of anorexia, loss of balance, moribundity and
darkness in skin colour were referred to Laboratory of Aquatic Diseases of
Veterinary Faculty, University of Tehran. After the survey of ectoparasites,
necropsy was performed under aseptic conditions; bacterial culture on
standard media was done and the alimentary canal was extruded. In both fish
no ectoparasite was detected and no bacteria from these cases grew on the
standard media. In internal survey 5 and 25 nematodes were detected in each
fish. A high number of free eggs were observed in intestine of fish.
Regarding morphological characteristics of the nematodes and their eggs, they
were identified as Capillaria sp. Treatment of other fish with levamisole was
effective and the loss was terminated. Some helminthes like Capillaria
pterophylli Heinze, 1933, can cause a high mortality in cichlid aquarium
fishes. This study showed that infection with some species of Capillaria
could cause a heavy loss in ornamental fish from Cichlidae. Diagnosis of
parasites of these fishes can help us to prevent high mortalities.
Principles of fish welfare assessment in farm rearing conditions
Authors: Relic Renata , Hristov Slavca , Vucinic Marijana , Poleksic Vesna , Markovic Zoran
Published: July 2011

For several decades fish welfare has been subject of many researches, and the
interest for this subject is connected with the fact that fish can feel pain
and suffering. In addition to this stressors? mechanisms of action and their
consequences are similar in mammals and fish. Assessment of welfare for
farmed fish is based on the same principles as for terrestrial farm animals.
However, special methods of collecting data are needed due to morphological
characteristics of fish and properties of their environment. In the world and
in our country, researches of different ways of fish welfare assessment are
being conducted, especially based on non-invasive techniques such as
monitoring of behaviour. In this paper a review of basic principles and
methods used in assessment of farmed fish welfare is given.
Prediction of size distribution of iron ore granules and permeability of its bed
Authors: Lv X. , Bai C. , Huang X. , Qiu G.
Published: July 2011

The granulation process, which is determined by many factors like properties
of the mixture and the operating parameters, is of very importance for
getting a good permeability of the burden in the sintering strand. The
prediction of the size distribution of the granules and the permeability of
its bed by the artificial neural network was studied in this paper. It was
found by the experiments that the order of significance in the granulation
process is water content added into the mixture, the mass fraction of the
particles of 0.7-3 mm, and the moisture capacity. The water content added in
the mixture and the mass fractions of the particles of 0.7-3 mm have the
positive relation to the permeability of granulation, While, the moisture
capacity has the negative relation to the permeability of granulation. Both
the moisture capacity and the water content added were used as the inputs in
the model of artificial neural network, which can give a good prediction on
the permeability and mass fraction of the granules of 3-8 mm, as well as the
tendency of the samples under instable raw materials conditions. These two
models can be used for optimization the granulation.
Monitoring of radionuclides in carbon steel blooms produced by EAF process
Authors: Sofilic T. , Barisic D. , Sofilic U. , Zivkovic J.
Published: July 2011

Because natural and artificial isotopes in steel might originate from steel
scrap or from the residue of the material that was used in the technological
process, thus monitoring especially artificial radionuclides 60Co, 137Cs and
192Ir deserve special attention. The analysis by g-spectrometry has been
applied to determine the presence of natural isotopes 40K, 226Ra, 232Th and
238U as well as of the artificial isotope 60Co, 137Cs and 192Ir and their
activity in the produced steel round blooms in the Steel Mill of CMC Sisak
d.o.o. At the same time the content of radionuclides in the other materials
(ferroalloys, bauxite, fluorite, lime, coke, graphite electrodes, refractory
blocks) used in the same steel making process was investigated. The measured
values regarding the presence of individual isotopes and their activity in
steel were as follows: 40K all values were less than 1.6 Bqkg-1; 232Th all
activities values were less than 0.02 Bqkg-1; 226Ra all activities values
were less than 0.01 Bqkg-1; 238U all activities values were less than 1.10
Bqkg-1; 60Co all activities values were less than 0.02 Bqkg-1; 192Ir all
activities values were less than 0.02 Bqkg-1 and 137Cs all activities values
were less than 0.30 Bqkg-1.
Analysis of natural radionuclides in coal, slag and ash in coal-fired power plants in Serbia
Authors: Jankovic M.M. , Todorovic D.J. , Nikolic J.D.
Published: July 2011

The radioactivity monitoring in the ?Nikola Tesla?, ?Kolubara?, ?Morava? and
?Kostolac? coal-fired power plants was performed by the Radiation and
Environmental Protection Laboratory, Vinca Institute of nuclear sciences in
the period 2003-2010. Monitoring included the analysis of soil, water, flying
ash, slag, coal and plants. This paper presents the results of the
radioactivity analysis of coal, ash and slag samples. Naturally occurring
radionuclides 226Ra, 232Th, 40K, 235U, 238U, and 210Pb as well as the
man-made radionuclide 137Cs were determined by gamma spectrometry using HPGe
detector. The concentrations of pairs of radionuclides were statistically
tested to determine the correlation between them. Based on the obtained
results, health effect due to the activity of these radionuclides was
estimated via radium equivalent (Raeq), external hazard index (Hex), external
gamma absorbed dose rate () and annual effective dose.
Synthesis and characterization of the Bi2-xHox/2Zr3x/8O3 compounds
Authors: Sulcová P. , Bystrzycki P. , Válek L. , Trojan M.
Published: July 2011

A series of novel environmentally inorganic pigments based on Bi2O3 doped by
metal ions such as Zr4+ and Ho3+ have been developed and characterized using
of methods of thermal analysis, Xray powder diffraction and CIE L
Avrami behavior of magnetite nanoparticles formation in co-precipitation process
Authors: Ahmadi R. , Hosseini Madaah , Masoudi A.
Published: July 2011

In this work, magnetite nanoparticles (mean particle size about 20 nm) were
synthesized via coprecipitation method. In order to investigate the kinetics
of nanoparticle formation, variation in the amount of reactants within the
process was measured using pH-meter and atomic absorption spectroscopy (AAS)
instruments. Results show that nanoparticle formation behavior can be
described by Avrami equations. Transmission electron microscopy (TEM) and
X-ray diffraction (XRD) were performed to study the chemical and
morphological characterization of nanoparticles. Some simplifying assumptions
were employed for estimating the nucleation and growth rate of magnetite
nanoparticles.
Ternary invariant point at 374°C in the three phase region AlSb-Al-Zn inside the Al-Sb-Zn ternary system
Authors: Klancnik G. , Medved J.
Published: July 2011

Al-Sb-Zn ternary system was investigated in the three phase region
Al-AlSb-Zn, using differential thermal analysis (DTA), differential scanning
calorimetry (DSC) and scanning electron microscope equipped with energy
dispersive spectrometer (SEM-EDS). The position and temperature of the
invariant eutectic L ? AlSb + ?-Al + ? - Zn point inside Al-AlSb-Zn region
was experimentally determined. To confirm the obtained results X-ray powder
diffraction analysis or XRD was also done. All results were compared to the
calculated isopleth phase diagrams using Thermo-Calc software (TCW 5). All
calculations were done using the SSOL4 data base.
Crystallization kinetics accountability and the correspondingly developed glass-forming criteria: A personal recollection at the forty years anniversaries
Authors: Sesták J. , Kozmidis-Petrovic A. , Zivkovic Z.
Published: July 2011

The meaning of experimentally determined characteristic temperatures is
analyzed in terms of Hruby glass forming criterion. Despite various analyzed
modifications it reveals that the sensitivity of original criterion is
unsurpassable. The applicability of Sestak-Berggren empirical equation for
the description of crystallisation kinetics is comparable with the classical
modelling based on Johnson-Mehl-Avrami equation. Their employment is
certainly dependent to the purpose of evaluation showing their substitution
ability and limits.
On the five base quantities of nature and SI (The International System of Units)
Authors: Kaptay G.
Published: July 2011

It is shown here that five base quantities (and the corresponding five base
units) of nature are sufficient to define all derived quantities (and their
units) and to describe all natural phenomena. The base quantities (and their
base units) are: length (m), mass (kg), time (s), temperature (K) and
electric charge (C). The amount of substance (mole) is not taken as a base
quantity of nature and the Avogadro constant is not considered as a
fundamental constant of nature, as they are both based on an arbitrary
definition (due to the arbitrary value of 0.012 kg for the mass of 1 mole of
C-12 isotope). Therefore, the amount of substance (mole) is moved from the
list of base quantities to the category of the supplementary units (to be
re-created after its abrogation in 1995). Based on its definition, the
luminous intensity (cd) is not a base quantity (unit), therefore it is moved
to the list of derived quantities (units). The ampere and coulomb are
exchanged by places in the list of base and derived units, as ampere is a
speed of coulombs (but SI defines meter, not its speed as a base unit). The
five base quantities are re-defined in this paper by connecting them to five
fundamental constants of nature (the most accurately known frequency of the
hydrogen atom, the speed of light, the Planck constant, the Boltzmann
constant and the elementary charge) with their numerical values fixed in
accordance with their CODATA 2006 values (to be improved by further
experiments).
Olive leaf extract modulates cold restraint stress-induced oxidative changes in rat liver
Authors: Dekanski Dragana , Ristic Slavica , Radonjic Nevena , Petronijevic Natasa , Dekanski Aleksandar , Mitrovic Dusan
Published: July 2011

Recently, demonstrated the beneficial effects of different single doses of
standardized dry olive (Olea europaea L.) leaf extract (OLE) in cold
restraint stress (CRS)-induced gastric lesions in rats and its influence on
oxidative parameters in gastric mucosa were demonstrated. The present study
was undertaken to investigate the long-term pretreatment efficacy of OLE and
its potential in the modulation of CRS-induced oxidative changes at the liver
level. The experimental animals were divided into four groups, i.e., control,
OLE-treated, CRS non-treated and CRS treated with OLE (CRS+OLE) groups. CRS
caused severe gastric lesions in all non-pretreated animals and two-week
pretreatment with OLE (80 mg kg-1 b.w.) attenuated stress-induced gastric
lesions significantly. The malondialdehyde (MDA) level as an index of lipid
peroxidation, superoxide dismutase (SOD) and catalase (CAT) activities were
measured spectrophotometrically in liver tissue homogenates. The MDA level
was increased in the CRS group and significantly decreased in the CRS+OLE
group. The SOD and CAT activities were significantly decreased in the CRS
group. In the CRS+OLE group, the activities of these two enzymes were
significantly increased in comparison with the CRS group. The results
obtained indicate that long-term supplementation with OLE provides
oxidant/antioxidant balance in liver during stress condition.
Second demographic transition de-blocked?
Authors: Bobic Mirjana , Vukelic Jelisaveta
Published: July 2011

The text is re-examining the previously established dilemma related to
whether Serbia (without Kosovo and Metohija) is the country of second
demographic transition, i.e.: has the transition been de-blocked, under the
assumption that this is a worldwide historical process of transformation of
industrialized countries. The last thesis, around which there exists a lot of
controversy in the contemporary population theory, is however not dealt with
in detail; to the contrary, it is used as the general theoretical framework
for the exploration of the most recent tendencies in the transformation of
nuptiality and fertility regime in Serbia, as well as in the western and
countries in post-socialist transformation. Special attention is given to the
ideational changes, more precisely to the specific features of the value
profile of the Serbian population, which is one of the most important
determinants of the societal framework, that acts in the back of the afore
mentioned aggregate demographic indicators. Finally, the hypothesis is posed
(which should be further investigated by means of in-depth research and
complementary approach) that the speeding-up of the second demographic
transition and intensification of the individualisation not only of the
partnership but of the parenthood as well, accompanied with the rise of
living standard and social support to balancing work and family, would have
produced important emancipating and, concomitantly, positive socioeconomic
and demographic effects.