bluuebunny/crossref_metadata_2025 huggingface dataset:
Combining Step-Rate Well Test with Transient-Pressure Test: Is it Possible?
Authors: Silin Dmitriy , Robin George
Published: March 2009

The step rate well test (SRT) is a well-established tool for estimating formation parting pressure. The procedure consists of a sequence of injection intervals, on each of which the injection rate is constant. The rate increments between the intervals are usually the same, and the time durations of these intervals are equal to each other. A conventional transient pressure test requires the well to be shut-in for a substantial period of time in order to estimate hydraulic formation properties in the vicinity of the wellbore. Combining these two tests in one offers great benefits, since each test requires interruption of regular operations and providing storage capacities for storing the injectate until operations can be resumed.

Step-rate test evaluation is based on a single data point for each interval. However, if one saves the data points covering transition from one rate to another, this information can be used for transient analysis. Moreover, transient analysis of SRT data can provide an estimate of the parting pressure with a higher accuracy. We will present a theoretical justification of this statement, and show examples of transient analysis of SRT data using the ODA (Operations Data Analysis) code.
Cost-Effective Production-Enhancement Solution for Heavy Oil
Authors: Gorham Tim , Rodriguez Samuel E. , Wise John , Ripley Michael , Dyer Richard J.
Published: March 2009

Heavy oil, oil < 17o API, accounts for a growing percentage of the production and reserve portfolios of North American Oil Producing Companies. A key challenge in the production of heavy oil is that its properties provide a greater likelihood of common damage mechanisms and result in a drop in production rates.

Historically, operators of heavy oil reservoirs have used several options to address the common damage mechanisms of asphaltene, paraffin and inorganic scale depositions, as well as wettability changes in order to increase the production of their existing wells. However these options are generally limited to costly and resource consuming methods such as cyclic steam injection and workover rig based liner or perforation washes.

A cost effective alternative production enhancement process to these types of well interventions has been implemented in the Midway Sunset heavy oil field (Kern County, California). This alternative production enhancement process is based on a combination of candidate selection practices and a unique blend of solvents, surfactants, and acid. To date 2,500+ individual well treatments have been performed in a field wide application of this technology. A 27% average increase in oil production rates was observed for the wells that were treated. On a well by well basis a 73% economic success rate was achieved with an overall project economic return of greater than 500% ROI. This process significantly reduces the reliance solely upon workover rigs and steam for stimulation purposes. Additionally production downtime is limited to twenty four to forty eight hours and repeat applications to maintain increased production are only required every 90-120 days.

As with many tools and techniques in the oilfield, proper well selection and application directly affects the effectiveness of the tool or technology. The modifiable, multifunctional treatment fluid allows for the remediation of depositional damage mechanisms such as asphaltenes, paraffin, and inorganic scales and allows for wettability modification to restore the near-wellbore region to a water wet state.
Continued Development of Mature Heavy-Oil Field With Strong Waterdrive Using Mechanistic Reservoir Simulation
Authors: Han Mei , Tajer Ehsan S. , Fox Carrie M. , Behm Ed J.
Published: March 2009

Recent success with horizontal infill wells is evaluated using mechanistic modeling to aid in the understanding of observed performance and then assesses potential for unswept regions and additional drilling opportunties.

A mechanistic simulation approach is used to model the reservoir because few modern logs and only key production rates are available. Historical reservoir pressure, oil rates and water cuts of vertical and recent horizontal wells were modeled successfully. The model shows that edge-water drive has limited effect on oil displacement in the upper-section of reservoir with proximity to the aquifer. Early vertical wells drilled in this area had low oil recovery because of the bottom water. Recent horizontal well production performance has bolstered confidence to drill near the edges of the field to provide additional incremental production. Recent drilling results support these findings.

Mechanistic simulation approach was successfully used as a fast and efficient technique to understand recovery mechanisms and exploit potential.
Reserves in Unconventional Reservoirs: Effect of New SEC Rules
Authors: Lee W. John
Published: March 2009

The United States Securities and Exchange Commission, on December 29 2008, adopted new rules for disclosing oil and gas reserves. The definitions contained within these rules are broadly consistent with the SPE Petroleum Resources Management System (PRMS); the definitions in the previous rules differed from PRMS in a number of specific instances. A notable difference in the new rules is inclusion of more unconventional resources as potential oil and gas reserves rather than as mining reserves. These new rules offer enhanced opportunities for investors to understand the potential values of oil and gas companies and for companies to access the capital markets in the United States more efficiently.

Disclaimer

The opinions expressed in this paper are mine alone, and represent neither the opinions of the United States Securities and Exchange Commission nor of its staff members.
Diversity and Mega‐Targets of Selection from the Characterization of a Barley Collection
Authors: Gutiérrez Lucía , Nason John D. , Jannink Jean‐Luc
Published: March 2009

Germplasm exchange is essential for assuring genetic gain in a breeding program. Two aspects of breeding programs are relevant to making them compatible for germplasm exchange: the amount of genetic diversity within programs and the identification of breeding programs with similar breeding objectives and environments of selection (i.e., mega‐targets of selection). The objective of this study was to develop a data‐driven method to group breeding programs likely to be compatible for germplasm exchange and to use phenotypic characterization data of barley (Hordeum vulgare L.) from breeding programs to illustrate this method. In two locations in Uruguay we evaluated 20 traits in 353 genotypes of barley from 23 private and public breeding programs distributed worldwide. We found significant amounts of genetic diversity for all traits, but differences in diversity among programs for only seven traits. We identified programs with high (Western Australia Department of Agriculture; University of Saskatchewan; and Svalöf Weibull Ab, Sweden) and low diversity (winter program of Osijek Agricultural Institute, Croatia; spring program of Osijek Agricultural Institute, Croatia; Saatzucht Josef Breun, Germany; Busch Agricultural Resources; USDA‐ARS, Aberdeen, ID; and University of Minnesota). We developed a methodology that groups programs with similar performance and response to the environments. We used the methodology to group the 23 breeding programs of barley into sets that might benefit most from germplasm exchange. The identification of compatible programs for germplasm exchange could be relevant for improving genetic gains in breeding programs.
Population Structure and Genetic Diversity of the Trinitario Cacao (Theobroma cacao L.) from Trinidad and Tobago
Authors: Johnson Elizabeth S. , Bekele Frances L. , Brown Steven J. , Song Qijian , Zhang Dapeng , Meinhardt Lyndel W. , Schnell Raymond J.
Published: March 2009

Population structure of the old Trinitario cacao (Theobroma cacao L.) in Trinidad was evaluated from the 35‐microsatellite multilocus profile of 32 relict clones from abandoned cocoa estates in Trinidad (TRD) and 88 Imperial College selections (ICS) clones conserved in the International Cocoa Genebank, Trinidad. Ancestry was derived by comparison to 34 representative genotypes of Criollo, Central American, and Lower and Upper Amazon origin. The 154 individuals separated into four populations in this study, labeled Population 1—Upper Amazon; Population 2—Ecuadorian; Population 3—Lower Amazon; and Population 4—Trinitario. Over 90% of the individuals demonstrated 70 to 99% membership to their respective populations. The ICS and TRD clones formed a genetically homogenous group, 84% of which clustered in Population 4 with clones of pure Criollo descent. Another 10% clustered in Population 1 containing clones of Upper Amazon descent. The cacao population of Trinidad is genetically different from clones of Ecuadorian and Lower Amazon descent, Populations 2 and 3, respectively. The 10 most discriminating loci for each population were different as shown by polymorphism information content values for each of the 35 microsatellite loci. This is the first report to provide a strong genetic basis for the industry flavor distinction of Trinitario and Ecuadorian cacaos. These findings significantly impact germplasm fingerprinting and curatorship and maintenance of industry flavor classes while breeding for disease resistance in cacao.
Enhanced Tolerance to Oxidative Stress with Elevated Antioxidant Capacity in Doubled Haploid Maize Derived from Microspores Exposed to Paraquat
Authors: Darkó Éva , Ambrus Helga , Fodor József , Király Zoltán , Barnabás Beáta
Published: March 2009

To improve the oxidative stress tolerance of maize (Zea mays L.), doubled‐haploid (DH) plants were regenerated from in vitro selected microspores exposed to paraquat. The efficiency of in vitro selection was tested by physiological and biochemical investigations, in which the tolerance to paraquat‐mediated oxidative damage and antioxidant capacity of the second generation of fertile microspore‐selected lines (DH2) were determined. In the leaves of paraquat‐selected DH2 lines, reduced accumulation of reactive oxygen species, lower rates of chlorophyll bleaching, protein breakdown and membrane damage, but higher photosynthetic activity were detected on exposure to paraquat stress than either in the leaves of nonselected DH2 lines or in the original hybrid used as controls. The tolerant DH2 plants showed elevated activities of antioxidant enzymes such as superoxide dismutase, ascorbate peroxidase, glutathione reductase, glutathione S‐transferase, and catalase as compared to both controls. These results suggest that elevated antioxidant capacity may contribute to the paraquat tolerance of the paraquat‐selected DH2 lines and that in vitro microspore selection represents a potential way to improve oxidative stress tolerance in maize.
Morphology and Genetics of Biomass in Little Bluestem
Authors: Boe Arvid , Bortnem Robin
Published: March 2009

Little bluestem [Schizachyrium scoparium (Michx.) Nash] was the most important dominant species of uplands in the tallgrass prairie. Presently, it is a dominant species, most significantly on coarse‐textured soils, in the mixed‐grass prairie region of the United States and Canada. This wide geographical adaptation to dry soils suggests little bluestem has potential for biomass production in areas unsuitable for most other grass species in the North American steppe. Primary objectives of this research were to (i) describe the morphology and determine the distribution of biomass among main stem and axillary components of little bluestem, and (ii) determine genetic variation for morphology and biomass production in ‘Camper’ little bluestem. Morphological analysis was conducted on tillers collected from natural populations in South Dakota and Montana and from swards of Camper and ‘Badlands’ ecotype in eastern South Dakota. Sixteen genotypes of Camper were evaluated for three years at two locations for determination of genotypic variation for biomass and biomass components. Quadratic models explained relationships between phytomer position and leaf and internode lengths and mass of individual phytomers of natural and selected populations. Genotypic variation occurred for phytomers per tiller, tillers per plant, mass per tiller, axillary branches per tiller, and biomass (range: 102–387 g plant−1). However, the correlation between locations for biomass was not significant for genotypes due to genetic variation for phenotypic plasticity. High frequency of survival over two winters for all genotypes indicated Camper has adequate winter hardiness to serve as a source population for cultivar development for biomass in the northern Great Plains.
Introgression of Wild Species Germplasm with Extreme Resistance to Cold Sweetening into the Cultivated Potato
Authors: Hamernik A. J. , Hanneman R. E. , Jansky S. H.
Published: March 2009

Potato (Solanum tuberosum L.) breeders are interested in developing chipping cultivars that can be stored at cold temperatures to reduce storage losses and increase profitability for potato producers. Commercial cultivars accumulate reducing sugars during cold storage, resulting in unacceptably dark chips when processed. In this study, we have identified diploid wild Solanum species accessions that are resistant to cold‐induced sweetening at very low storage temperatures (2°C). Selected accessions were crossed as males to haploids (2n = 2x) of S. tuberosum to produce adapted hybrids, some of which produce acceptable chips following 3 mo of storage at 2°C. Reconditioning for 6 d at 20 to 22°C increased the number of clones with acceptable chip scores by threefold. The best wild species parents were S. raphanifolium 296126, 310998, and 210048. While parental chip scores help to predict offspring performance, progeny testing is important to identify the best cross combinations. The best hybrids have been introgressed into diploid and tetraploid breeding clones. These hybrids produce good tuber type and low levels of reducing sugars under extremely low storage temperatures.
Salinity Effects on Seed Germination and Vegetative Growth of Greens‐Type Poa annua Relative to Other Cool‐Season Turfgrass Species
Authors: Dai Jing , Huff David R. , Schlossberg Maxim J.
Published: March 2009

Seed germination and vegetative growth studies were conducted to determine relative salinity tolerance of greens‐type Poa annua L. compared with other cool‐season turfgrass species. Effects of increasing salinity stress on final germination percentage (FGP), germination rate (GR), clipping yield dry weight (CYD), verdure dry weight (VD), root dry weight (RD), and the longest root length (LRL) were evaluated for nine experimental lines of greens‐type P. annua, two cultivars of Kentucky bluegrass (P. pratensis L.), three cultivars of creeping bentgrass (Agrostis stolonifera L.), and one cultivar of perennial ryegrass (Lolium perenne L.). Generally, FGP, GR, CYD, VD, and RD declined with increasing salinity; LRL increased at lower salinity levels but decreased at higher levels. Perennial ryegrass ‘Charger II’ and creeping bentgrass ‘Mariner’ exhibited the most salinity tolerance while Kentucky bluegrass cultivars exhibited the least. Salinity tolerance of greens‐type P. annua was intermediate; however, some experimental lines exhibited nearly equal salinity tolerance to that of Mariner. Our data suggest greens‐type P. annua possesses moderate to good salinity tolerance during seed germination and vegetative growth relative to other cool‐season turfgrass species and has potential to be used on golf courses with moderate salt problems affecting turf establishment and maintenance.
Genetic Diversity for Pink Snow Mold Resistance in Greens‐Type Annual Bluegrass
Authors: Bertrand Annick , Castonguay Yves , Cloutier Jean , Couture Luc , Hsiang Tom , Dionne Julie , Laberge Serge
Published: March 2009

Unseeded annual bluegrass (Poa annua L.) is an important component of golf greens in many regions of Canada and the United States. Although this turfgrass species has desirable playing attributes, it suffers from susceptibility to environmental and biological stresses including subfreezing temperatures and snow molds. In this study, we compared 29 genotypes collected from golf greens located in Québec and Ontario for their resistance to pink snow mold (SM). Plants were inoculated with Microdochium nivale [(Fries) Samuels & Hallett], causal agent of SM, and incubated under controlled conditions. High levels of variation in SM resistance were detected within the collection and between genotypes. Analysis of the relationship between climatic parameters at the sites of origin and SM susceptibility revealed that level of resistance was positively correlated to the duration of snow cover. Genetic diversity within the Poa collection was estimated using the sequence related amplified polymorphism (SRAP) technique. The UPGMA (unweighted‐pair group method arithmetic average) dendrogram yielded two main clusters that differed markedly in their proportion of SM‐resistant genotypes. Our results show that SM disease is a major selection pressure for the generation of genetic diversity among annual bluegrass biotypes that evolved on golf greens in northern climates. SRAP polymorphisms between bulked genotypes with contrasting resistance to SM were identified and could be used as markers for SM resistance in annual bluegrass.
Prairie and Turfgrass Buffer Strips Modify Water Infiltration and Leachate Resulting from Impervious Surface Runoff
Authors: Steinke K. , Stier J.C. , Kussow W.R.
Published: March 2009

Concerns over NO3–N concentrations in drinking water and potential subsurface transport of P to surface waters are driving legislation on precautionary N and P application restrictions on turfgrass areas and in recommendations for vegetative plantings within urban environments. Two plant communities and three impervious:pervious surface ratios were examined for effects on leachate water quantity and quality over a 3‐yr period. A Kentucky bluegrass blend (Poa pratensis L.) and a mixed forb and grass prairie were monitored for 3 yr for total leachate volumes, total dissolved N (TDN) loading, and soluble PO4–P loading. Both types of vegetation provided similar annual groundwater recharge rates. Annual TDN losses from fertilized turf and unfertilized prairie were similar during and after establishment, with postestablishment losses averaging 3.6 and 2.2 kg ha−1, respectively. Mean annual soluble PO4–P losses postestablishment were 0.6 and 0.7 kg ha−1 for fertilized turf and unfertilized prairie, respectively. When compared with the absence of a buffer area, pervious surfaces at least one‐half the size of impervious surfaces resulted in at least a 50% reduction in drainage water volumes. Fertilized turfgrass and unfertilized prairie vegetation provided similar groundwater protection and recharge abilities, and both resulted in some natural biogeochemical nutrient cycling.
Mapping and Comparison of Quantitative Trait Loci for Oleic Acid Seed Content in Two Segregating Soybean Populations
Authors: Bachlava Eleni , Dewey Ralph E. , Burton Joseph W. , Cardinal Andrea J.
Published: March 2009

Soybean [Glycine max (L.) Merr.] produces 29.4% of the world's edible vegetable oil. An important determinant of the nutritional value and the oxidative stability of soybean oil is the oleic acid content. Elevation of the oleate content levels leads to the improvement of soybean oil quality. However, our knowledge of the genetic factors underlying oleate variation in soybean seeds remains incomplete, hampering the use of marker‐assisted selection in soybean breeding programs. We used a whole‐genome scan approach to identify oleate quantitative trait loci (QTLs) in a soybean population segregating for oleic acid content and a cognate segregating population to confirm oleate QTL. A novel oleate QTL with moderate effects was revealed on linkage group F in the proximity of the simple sequence repeat marker sat_309, which was confirmed in both populations across all environments tested. Furthermore, this study verified the existence of an oleate QTL with moderate effects in the proximity of FAD2‐1B isoform on linkage group I, which interacted epistatically with the oleate QTL on linkage group F. Oleate QTLs with moderate effects were also detected on linkage groups A2 and N only in one of the populations under study. Minor QTLs on linkage groups E, L, A1, and D2 confirmed previous mapping studies for oleate content in soybean.
Effects of Long‐Term Selection for Kernel Oil Concentration in KYHO, a High‐Oil Maize Population
Authors: Wang Hong‐Wu , Wu Bang‐Yang , Song Tong‐Ming , Chen Shao‐Jiang
Published: March 2009

A high‐oil maize (Zea mays L.) (HOM) population, KYHO, was developed across 10 generations by selective breeding. The objectives of this investigation were to evaluate the effects of selection for kernel oil on correlated traits and measure the genetic variance of kernel oil content (KOC). Kernel oil content, kernel protein content (KPC), and kernel starch content (KSC) were estimated by near‐infrared reflectance spectroscopy (NIRS); palmitic, stearic, oleic, linoleic, linolenic, and arachidic fatty acids were analyzed by gas chromatography. Also measured at the appropriate time during the growth cycle were plant anthesis (AT), plant height (PH), ear height (EH), 100 kernels weight (KW), and red ear cob ratio (RCR). Sampling and measurement of the various parameters occurred under the same conditions for each generation for three years. Kernel oil content greatly increased from 3.53% in cycle 0 to 12.66% in cycle 10; the predicted selection response per cycle was 1.01 ± 0.05%. The realized heritability (h2R) and broad‐sense heritability (h2B) of KOC in KYHO were 0.38 and 0.99 respectively, suggesting significant genetic variability, especially additive variance, across 11 selection cycles. The correlated traits of stearic, oleic, unsaturated fatty acid, and KPC and RCR increased steadily from the original generation to the final cycle (C10), whereas the remaining parameters decreased. There were significant (P ≤ 0.01) genotypic and phenotypic correlations between KOC and all measured traits, with the exception of arachidic acid. Red ear cob ratio was significantly positively correlated with KOC, and increased 7.41% with each 1% KOC increase.
The Putative Mesoamerican Domestication Center of Phaseolus vulgaris Is Located in the Lerma–Santiago Basin of Mexico
Authors: Kwak Myounghai , Kami James A. , Gepts Paul
Published: March 2009

Mesoamerican food agriculture is defined by the milpa cropping system, consisting of maize (Zea mays L.), common bean (Phaseolus vulgaris L.), and squash (Cucurbita spp.). In recent years, a domestication center for maize has been proposed in the Balsas River basin in west‐central Mexico, raising the question whether the Balsas basin was also the center of origin for Mesoamerican food agriculture in general. We conducted a survey of genetic diversity for 26 microsatellite markers in a representative sample of 155 wild and domesticated common bean from its Mesoamerican gene pool. Microsatellite diversity was analyzed with STRUCTURE, neighbor‐joining tree construction, and principal coordinate analysis. Most Mesoamerican domesticated accessions clustered in a single group, suggesting a single domestication. Furthermore, the most closely related wild beans to the domesticated clade originated from a restricted region in the Rio Lerma–Rio Grande de Santiago basin in west‐central Mexico, distinct from the Balsas basin. Although wild maize and Phaseolus beans grow together in the wild, they appear to have been domesticated in different regions to be reunited later on in a single cropping system. Crop domestications in Mesoamerica may therefore have a diffuse rather than a single geographic origin. Archaeological and ecological investigations into the origins of agriculture should be refocused from the arid eastern half of Mexico to the west‐central part of the country.
Money creation, employment and economic stability: The monetary theory of unemployment and inflation
Authors: Parguez Alain
Published: March 2009

This paper by building on the general theory of the monetary circuit, proves that money-as a pure bank credit liability-exists to overcome constraints on required expenditures by firms, household and mainly the State. From this perspective the paper derives the employment function in the modern monetary economy. Thereby it is explained that full employment policy is both always possible and required. It is proven that this conclusion holds in a perfectly open economy. Ultimately it is explained that there is no trade-off between full employment and sustainable price stability.
Goodbye Washington Consensus, hello Washington confusion?: A review of the World Bank's 'Economic growth in the 1990s: Learning from a decade of reform'
Authors: Rodrik Dani
Published: March 2009

Proponents and critics alike agree that the policies spawned by the Washington Consensus have not produced the desired results. The debate now is not over whether the Washington Consensus is dead or alive, but over what will replace it. An important marker in this intellectual terrain is the World Bank's Economic Growth in the 1990s- Learning from a Decade of Reform (2005).With its emphasis on humility, policy diversity, selective and modest reforms, and experimentation, this is a rather extraordinary document demonstrating the extent to which the thinking of the development policy community has been transformed over the years. But there are other competing perspectives as well. One (trumpeted elsewhere in Washington) puts faith on extensive institutional reform, and another (exemplified by the U.N. Millennium Report) puts faith on foreign aid. Sorting intelligently among these diverse perspectives requires an explicitly diagnostic approach that recognizes that the binding constraints on growth differ from setting to setting. .
A new era for the music industry: How new technologies and the internet affect the way music is valued and have an impact on output quality
Authors: Patokos Tassos
Published: March 2009

Since its early days, the Internet has been used by the music industry as a powerful marketing tool to promote artists and their products. Nevertheless, technology developments of the past ten years, and especially the ever-growing phenomenon of file sharing, have created the general impression that the Internet is responsible for a crisis within the industry, on the grounds that music piracy has become more serious than it has ever been. The purpose of this paper is to present the impact of new technologies and the Internet on the three main actors of the music industry: consumers, artists and record companies. It is claimed that the Internet has changed the way music is valued, and also, that it may have a direct effect on the quality of the music produced, as perceived by both artists and consumers alike.
Zasto ce evro postati rival dolaru
Authors: Chinn Menzie , Frankel Jeffrey
Published: March 2009

nema
The co-integration of European stock markets after the launch of the euro
Authors: da Soares
Published: March 2009

This article studies the international integration of the national stock markets of sixteen European countries. The international financial market is represented by two indices: a European index and a World index. The methodology of co-integration, used in this article, is the proper econometrical solution for the treatment of non-stationary series as those used in the present research. Complementarily, co-integration offers the possibility of distinguishing the long-term and the short-term interdependence, which very important when the variables are financial market indices. The empirical tests in this research have shown that both European and non European international factors are necessary to explain the international integration of the national stock markets under analysis. .
The demand for currency substitution
Authors: Seater John
Published: March 2009

nema
On genocide, economic reasons vs. ethnic passion
Authors: Ballet Jérôme , Bazin Damien , François-Régis Mahieu
Published: March 2009

The traditional vision of genocide is exogenous. In this framework, ethnics have a real sense. The economic approach of conflicts has expressed slight differences in the relation between ethnics and conflicts. However it does not reject this explanation. Here we propose an alternative approach, an endogenous vision of genocide. Genocide appears in society where social capital plays a major role in solidarities. But social capital is a weak asset in the individual portfolio. Economic and social shocks may have impacts on the assets structure and may produce conflicts such as genocide. In this new framework, policy makers may have to adopt prudential rules. .
New Cu(II), Co(II), and Ni(II) complexes with thieno[2,3-b]pyridine and 2-methylthieno[2,3-b]pyridine as ligands: Synthesis and crystal structures
Authors: Halgaš Ján , Kolenová Viera , Števíková Zuzana , Perašínová Lucia , Kožíšek Jozef
Published: March 2009

Although thienopyridines attract attention because of their biological activities, they have not been used as ligands in coordination compounds. Thieno[2,3-b]pyridine was prepared by known procedures; by reduction of 2-nitrothiophene, and reaction of the resulting 2-thienyl ammonium salt with malondialdehyde tetramethylacetal in the presence of zinc chloride. The same procedure was used for the preparation of a new derivative, 2-methylthieno[2,3-b]pyridine, starting from 2-methyl-5-nitrothiophene. The thienopyridines were used in the synthesis of coordination compounds. Chlorides, isothiocyanates, acetates, and chloroacetates of copper(II), nickel(II), or cobalt(II) were used as starting salts. The prepared complexes were characterized by elemental analysis and FT IR. Structures of the four complexes were determined by single-crystal X-ray diffraction analysis.
Global optimization for parameter estimation of differential-algebraic systems
Authors: Čižniar Michal , Podmajerský Marián , Hirmajer Tomáš , Fikar Miroslav , Latifi Abderrazak
Published: March 2009

The estimation of parameters in semi-empirical models is essential in numerous areas of engineering and applied science. In many cases, these models are described by a set of ordinary-differential equations or by a set of differential-algebraic equations. Due to the presence of non-convexities of functions participating in these equations, current gradient-based optimization methods can guarantee only locally optimal solutions. This deficiency can have a marked impact on the operation of chemical processes from the economical, environmental and safety points of view and it thus motivates the development of global optimization algorithms. This paper presents a global optimization method which guarantees ɛ-convergence to the global solution. The approach consists in the transformation of the dynamic optimization problem into a nonlinear programming problem (NLP) using the method of orthogonal collocation on finite elements. Rigorous convex underestimators of the nonconvex NLP problem are employed within the spatial branch-and-bound method and solved to global optimality. The proposed method was applied to two example problems dealing with parameter estimation from time series data.
Determination of alkaloids in Corydalis yanhusuo using hollow-fibre liquid phase microextraction and high performance liquid chromatography
Authors: Lu Huawei , Sun Huanquan , Liu Xia , Jiang Shengxiang
Published: March 2009

Hollow fibre based liquid phase microextraction (HF-LPME) with high performance liquid chromatography (HPLC) was developed for the determination of alkaloids in Corydalis yanhusuo. Three alkaloids (protopine, tetrahydropalmatine, tetrahydroberberine) were extracted from a 10 mL alkaline sample (donor phase) to an organic phase impregnated in the pores of the hollow fibre, and then, they were extracted to an acidic solution (acceptor phase) in the lumen of the fibre. The extract was determined directly by HPLC. Parameters affecting the HF-LPME include the organic solvent, pH of the donor and the acceptor phase, the extraction time and the stirring speed were investigated systematically. To minimize the error of the injection, palmatine was added as an internal standard (I.S.). Under optimal conditions, calibration curves were obtained in the range of 0.1–1.0 mg L−1 with a reasonable linearity (r 2 > 0.993) and the limits of detection (LODs) ranged between 10.0 × 10−3 mg L−1 and 13.7 × 10−3 mg L−1. Additionally, enrichment factors with 100 to 184-fold were obtained. The method was then applied to the crude extract of Corydalis yanhusuo successfully.
A rapid in vitro assay of cobalamin in human urine and medical tablets using ICP-MS
Authors: Zhang Gai , Liu Jianbo , Meng Zuchao , Wang Xin
Published: March 2009

A rapid and simple as well as sensitive inductively coupled plasma mass spectrometry (ICP-MS) method for the determination of cobalamin is described. Cobalamin in human urine and medicine tablet solutions was converted on-line into free cobalt ions in acid medium, the cobalt ions were then detected by ICP-MS. Cobalamin was determined by measuring the increase of integral counts per second intensity, which was linear over the cobalamin concentration range of 1.0 × 10−10 g mL−1 to 8.0 × 10−5 g mL−1, and the limit of detection was 0.05 ng mL−1 (3σ). At the pump rate of 30 rotations per minute, one analysis cycle of cobalamin, including sampling and washing, could be accomplished in 0.5 min with the relative standard deviations of less than 5 %. The proposed procedure was applied successfully in monitoring cobalamin in human urine without any pretreatment process and in rapid determination of cobalamin in multivitamin tablets.
A simple flow injection spectrophotometric determination method for iron(III) based on O-acetylsalicylhydroxamic acid complexation
Authors: Andac Muberra , Asan Adem , Isildak Ibrahim
Published: March 2009

A simple and rapid flow-injection spectrophotometric method for the determination of iron(III) and total iron is proposed. The method is based on the reaction between iron(III) and O-acetylsalicylhydroxamic acid (AcSHA) in a 2 % methanol solution resulting in an intense violet complex with strong absorption at 475 nm. Optimum conditions for the determination of iron(III) and the interfering ions were tested. The relative standard deviation for the determination of 5 μg L−1 iron(III) was 0.85 % (n = 10), and the limit of detection (blank signal plus three times the standard deviation of the blank) was 0.5 μg L−1, both based on the injection volumes of 20 μL. The method was successfully applied in the determination of iron(III) and total iron in water and ore samples. The method was verified by analysing a certified reference material Zn/Al/Cu 43XZ3F and also by the AAS method.
Deciding Between Acquisition and Joint Venture: Intangible Resources and Similarity
Authors: Montoro‐Sanchez Ángeles , Ortiz‐de‐Urbina‐Criado Marta
Published: March 2009

The aim of this paper is to analyze the influence of intangible assets and similarity of resources on the choice between acquisitions and joint ventures and whether it is different in domestic and European operations. In order to test these relations, a sample of domestic and European growth deals was selected (563 deals, of which 449 are acquisitions and 114 are joint ventures). Results demonstrate that it is more probable that firms will choose acquisitions if there is a close similarity between the resources of the firms. Also, if the operation is domestic, companies with higher proportions of intangible resources prefer acquisitions.
Barriers and Facilitators to Knowledge Management in University Research Centers: An Exploratory Study
Authors: Rego Arménio , Pinho Isabel , Pedrosa Júlio , Pina E. Cunha Miguel
Published: March 2009

This study shows how 152 researchers from several research centers of a Portuguese university perceive the facilitators and barriers to knowledge management. Three domains are considered – knowledge gathering, creation, and diffusion. Three dimensions of barriers and facilitators were considered – individuals, socio‐organizational processes, and technology. Regarding both barriers and facilitators, but mainly barriers, the findings suggest that researchers are more sensitive to the “soft” aspects of knowledge management (i.e., individuals, socio‐organizational processes) than to the “hard” ones (i.e., technology). This suggests that, although technology is an important facilitator, it is people and their interactions that create knowledge and promote the knowledge flow.
Birds of a Feather?: A Test of Cultural Homogeneity Among a Sample of Latin American Countries
Authors: Varela Otmar E. , Esqueda Sofia , Perez Olivia
Published: March 2009

This study tests the cultural invariance in Latin America utilizing a sample of four representative countries – Argentina, Colombia, Mexico, and Venezuela. With the participation of 915 individuals, samples were contrasted along seven cultural values (Schwartz, 1994) dictating the relationship of individuals with the society at large. Results challenge general notions conceiving of Latin America as a homogeneous bloc. Rather, outcomes indicate the presence of significant cultural disparities, adding to previous research by showing sample differentials in (1) mean importance ratings on values governing the behaviors of individuals beyond organizational settings and (2) the way values are behaviorally specified among samples. Findings are discussed in terms of restrictions in generalizing theories and managerial practices in the region. Avenues for future research are also highlighted.
The Psychological and Structural Determinants of Technology Integration in Organizations: An Empirical Study
Authors: Almeida Filipe , Sobral Filipe
Published: March 2009

The integration of information and communication technologies in a business context is currently an unquestionable strategic demand; however, companies do not always reveal identical information technology (IT) adoption levels. This paper addresses the manager’s attitude toward technology and the organizational structure as factors that may influence technological integration in a business context. The relationships among these variables are tested with a sample of Portuguese companies. Results support the hypothesis of manager’s attitude toward technology having an influence over the IT adoption level. However, the organizational structure adaptability seems not to have any influence on that same level. The results are discussed in light of current theory. This paper aims to highlight the important role of psychological and structural determinants in new technologies adoption processes in modern organizations.
Modulation of Iron-Regulatory Genes in Human Hepatocellular Carcinoma and Its Physiological Consequences
Authors: Tan Michelle Guet Khim , Kumarasinghe Marian Priyanthi , Wang Suk Mei , Ooi London Lucien P. J. , Aw Swee Eng , Hui Kam M.
Published: March 2009

Hepatocellular carcinoma (HCC) commonly develops in patients with underlying chronic liver disease. Additionally, the tumorous lesions of HCC patients are consistently characterized by the lack of iron accumulation even when arising in iron-loaded liver. However, the molecular mechanism leading to this observed phenomenon is currently poorly understood. In this study, all tumorous tissues from 24 HCC patients with chronic HBV infection were stained negative for iron when histologically assessed by Perls’ Prussian blue stain, whereas excess iron deposits were present in 17 of the 24 adjacent non-tumorous liver tissues. To elucidate the concerted regulation of iron homeostasis in these patients, we studied the gene expression profiling of 42 relevant iron-regulatory genes in the tumorous and adjacent non-tumorous liver tissues of these HCC patients along with 10 normal liver controls. Expression for most of the iron-regulatory genes, including hepcidin, transferrin receptor 2 (TfR2), transferrin (Tf), ceruloplasmin (Cp) and iron regulatory protein 1 (IRP1), were significantly down-regulated in the tumorous tissues of these patients compared to the adjacent non-tumorous liver tissues and normal liver controls. On the other hand, expression of hepcidin, TfR2, ferroportin 1 and DMT1 were significantly up-regulated in iron-loaded non-cirrhotic non-tumorous liver tissues as compared with normal liver controls. Hence, the reduction of hepcidin expression within the iron-depleted tumorous lesions likely reflects the physiological consequence of the obligate demand for iron in the rapidly growing neoplastic cells, whereas the up-regulation of hepcidin expression in the iron-loaded adjacent non-tumorous liver tissues is likely a physiological response.
Altered Mechanism of Adenosine-Induced Coronary Arteriolar Dilation in Early-Stage Metabolic Syndrome
Authors: Bender Shawn B. , Tune Johnathan D. , Borbouse Lena , Long Xin , Sturek Michael , Laughlin M. Harold
Published: March 2009

Onset of the combined metabolic syndrome (MetS) is a complex progressive process involving numerous cardiovascular risk factors. Although patients with established MetS exhibit reduced coronary flow reserve and individual components of the MetS reduce microvascular vasodilation, little is known concerning the impact of early-stage MetS on the mechanisms of coronary flow control. Therefore, we tested the hypothesis that coronary arteriolar dilation to adenosine is attenuated in early-stage MetS by reduced A2receptor function and diminished K+channel involvement. Pigs were fed control or high-fat/cholesterol diet for 9 weeks to induce early-stage MetS. Coronary atheroma was determined in vivo with intravascular ultrasound. In vivo coronary dilation was determined by intracoronary adenosine infusion. Further, apical coronary arterioles were isolated, cannulated and pressurized to 60 cmH2O for in vitro pharmacologic assessment of adenosine dilation. Coronary atheroma was not different between groups, indicating early-stage MetS. Coronary arteriolar dilation to adenosine ( in vivo) and 2-chloroadenosine (2-CAD; in vitro) was similar between groups. In control arterioles, 2-CAD-mediated dilation was reduced only by selective A2Areceptor inhibition, whereas only dual A2A/2Binhibition reduced this response in MetS arterioles. Arteriolar A2B, but not A2A, receptor protein expression was reduced by MetS. Blockade of voltage-dependent K+(Kv) channels reduced arteriolar sensitivity to 2-CAD in both groups, whereas ATP-sensitive K+(KATP) channel inhibition reduced sensitivity only in control arterioles. Our data indicate that the mechanisms mediating coronary arteriolar dilation to adenosine are altered in early-stage MetS prior to overt decrements in coronary vasodilator reserve.
Evaluating Recent Changes in Homicide and Robbery Rates
Authors: Rosenfeld Richard , Oliver Brian E.
Published: March 2009

This paper evaluates the Police Executive Research Forum's (PERF) recent warnings of a “gathering storm” of criminal violence in the United States. We argue that increases in violent crime during 2005 and 2006 were the expected result of year-to-year changes in the economy and imprisonment. Our argument is supported by an analysis of changes in homicide and robbery rates between 1970 and 2006 showing that short-run variation in homicide and robbery rates are a function of changes in imprisonment, the age composition of the population, and the economy. But PERF's warning of a new crime wave may simply have been premature. The steep economic downturn of 2008 portends a crime rise that may dwarf the 2005 and 2006 increases. Local communities and criminal justice practitioners should demand better research on crime trends that can help them evaluate current practice and plan for the future.
Reprogramming cell fates: reconciling rarity with robustness
Authors: Huang Sui
Published: March 2009

The stunning possibility of “reprogramming” differentiated somatic cells to express a pluripotent stem cell phenotype (iPS, induced pluripotent stem cell) and the “ground state” character of pluripotency reveal fundamental features of cell fate regulation that lie beyond existing paradigms. The rarity of reprogramming events appears to contradict the robustness with which the unfathomably complex phenotype of stem cells can reliably be generated. This apparent paradox, however, is naturally explained by the rugged “epigenetic landscape” with valleys representing “preprogrammed” attractor states that emerge from the dynamical constraints of the gene regulatory network. This article provides a pedagogical primer to the fundamental principles of gene regulatory networks as integrated dynamic systems and reviews recent insights in gene expression noise and fate determination, thereby offering a formal framework that may help us to understand why cell fate reprogramming events are inherently rare and yet so robust.
Computational identification of altered metabolism using gene expression and metabolic pathways
Authors: Nam Hojung , Lee Jinwon , Lee Doheon
Published: March 2009

Understanding altered metabolism is an important issue because altered metabolism is often revealed as a cause or an effect in pathogenesis. It has also been shown to be an important factor in the manipulation of an organism's metabolism in metabolic engineering. Unfortunately, it is not yet possible to measure the concentration levels of all metabolites in the genome‐wide scale of a metabolic network; consequently, a method that infers the alteration of metabolism is beneficial. The present study proposes a computational method that identifies genome‐wide altered metabolism by analyzing functional units of KEGG pathways. As control of a metabolic pathway is accomplished by altering the activity of at least one rate‐determining step enzyme, not all gene expressions of enzymes in the pathway demonstrate significant changes even if the pathway is altered. Therefore, we measure the alteration levels of a metabolic pathway by selectively observing expression levels of significantly changed genes in a pathway. The proposed method was applied to two strains of Saccharomyces cerevisiae gene expression profiles measured in very high‐gravity (VHG) fermentation. The method identified altered metabolic pathways whose properties are related to ethanol and osmotic stress responses which had been known to be observed in VHG fermentation because of the high sugar concentration in growth media and high ethanol concentration in fermentation products. With the identified altered pathways, the proposed method achieved best accuracy and sensitivity rates for the Red Star (RS) strain compared to other three related studies (gene‐set enrichment analysis (GSEA), significance analysis of microarray to gene set (SAM‐GS), reporter metabolite), and for the CEN.PK 113‐7D (CEN) strain, the proposed method and the GSEA method showed comparably similar performances. Biotechnol. Bioeng. 2009;103: 835–843. © 2009 Wiley Periodicals, Inc.
Models of Solute Aggregation Using Cellular Automata
Authors: Kier Lemont B. , Cheng Cho‐Kun , Nelson Jean D.
Published: March 2009

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A series of models using cellular automata (CA) are created to examine the influences on the phenomenon of solute aggregation. The models used the variations in hydropathic states of the solutes to produce changes in the clustering patterns. It was found that an increase in the hydrophobic character of the solute molecules led to greater aggregation. The effect of concentration of solutes was also modeled. These preliminary models of solute aggregation serve as the basis for subsequent models relative to both biological receptor interactions, and the fate and transport of environmental contaminants of interest.