bluuebunny/crossref_metadata_2025 huggingface dataset:
Convergence of carbohydrate-biased intake targets in caged worker honeybees fed different protein sources
Authors: Altaye Solomon Z. , Pirk Christian W. W. , Crewe Robin M. , Nicolson Susan W.
Published: September 2010

The nutritional needs of bees are supplied by nectar carbohydrates and by protein and other nutrients in pollen but little is known of how bees achieve nutritional balance. Using newly emerged caged worker honeybees (Apis mellifera scutellata), we investigated whether bees maintain their intake target when confined to pairs of imbalanced complementary diets varying in protein to carbohydrate (P:C) ratio. Diets were formulated using three protein sources [casein, royal jelly or Feed-Bee® (a natural pollen substitute)] and sucrose. Within each protein type, honeybees switched between complementary diets and converged on the same P:C intake target. However, this target differed between protein types: P:C ratios were 1:12, 1:14 and 1:11 on casein, royal jelly and Feed-Bee® diets, respectively. Except for an early peak in protein consumption on royal jelly diets, these strongly convergent ratios remained constant over the 14 day experiment. This is probably due to the absence of brood, reflected in relatively stable values measured for haemolymph protein concentration and hypopharyngeal gland activation in bees on Feed-Bee® diets. Performance of caged workers was also assessed in terms of survival and ovarian activation. Survival was highest on casein diets and lowest on Feed-Bee® diets but ovarian activation was highest on royal jelly diets and lowest on casein diets. This may be due to additional components in Feed-Bee® and royal jelly (e.g. fatty acids), which are needed to activate the ovaries but also reduce survival. Nutrient intake of broodless workers is directly related to their own physiological requirements, and the strong carbohydrate bias may reflect the high metabolic rate of honeybees even under resting conditions.
Deal or No Deal: Hormones and the Mergers and Acquisitions Game
Authors: Levi Maurice , Li Kai , Zhang Feng
Published: September 2010

Young male CEOs appear to be combative: they are 4% more likely to be acquisitive and, having initiated an acquisition, they are over 20% more likely to withdraw an offer. Furthermore, a young target male CEO is 2% more likely to force a bidder to resort to a tender offer. We argue that this combative nature is a result of testosterone levels that are higher in young males. Testosterone, a hormone associated with male dominance seeking, has been shown to influence prospects for a cooperative outcome of the ultimatum game. Specifically, high-testosterone responders tend to reject low offers even though this is against their interest. It has been argued that this is consistent with a low offer being seen as dominance seeking. The acts of attempting or resisting an acquisition can be viewed as striving to achieve dominance. We argue that the evidence reported in this paper is consistent with the presence of a significant hormone effect in mergers and acquisitions.
Trading Higher Software Piracy for Higher Profits: The Case of Phantom Piracy
Authors: Gopal Ram D. , Gupta Alok
Published: September 2010

Faced with the sustained problem of piracy that costs nearly $40 billion in annual revenue losses, the software industry has adopted a number of technical, legal, and economic strategies to curb piracy and stem the resulting losses. Our work complements and contributes to the existing literature by exploring the possible effect of another economic lever—product bundling—on the relationship governing piracy and seller profits. The traditional economic rationale of demand pooling from bundling that enables sellers to extract higher surplus and its particular attractiveness for information goods with negligible marginal and bundling costs carry over to our analysis. However, the presence of piracy injects several new facets to our analysis. Bundling creates a shared level of piracy of disparate products, and under certain conditions to the detriment of one of the products. We argue that by construction of the copyright laws, the act of bundling itself can have a deterrence effect. This deterrence effect, along with shared piracy of products and demand pooling are ingredients that together dictate the overall piracy, pricing, profit, and welfare outcomes. Our analysis reveals several interesting insights. Bundling can be profitable even when the very act of bundling increases the piracy level of one of the products in the bundle. Termed phantom piracy, this represents a situation where sellers trade off higher piracy for one product in favor of lower piracy for the other product while deriving overall higher profits. Extensive simulation analysis shows that the region of phantom piracy is vastly expanded when additional products are introduced to the bundle. Conversely, under certain conditions, a profit maximizing seller opts not to bundle even when bundling can serve to lower the overall level of piracy. Price discounts that are typically offered by bundling are sharply deepened when piracy enters the equation. When piracy is a phenomenon to contend with, product bundling always increases consumer surplus even in scenarios where the seller may not realize higher profits. Unlike other forms of price discrimination that are often viewed by consumers with a jaundiced eye as they attempt to extract additional surplus from the consumers, product bundling in the software context can be a win-win scenario for both the buyers and the sellers.
Qualitative detection of the Marburg I alloenzyme of factor VII-activating protease by an immunoassay and its comparison to PCR testing
Authors: Schwarz Herbert , Stephan Sina , Sidelmann Johannes J. , Fischer Bodo , Althaus Harald , Hahn Martin , Kappel Andreas , Ehm Matthias , Vitzthum Frank
Published: September 2010

Background: The Marburg I (MRI) single nucleotide poly-morphism (SNP) of the factor VII-activating protease (FSAP) gene has been associated with thrombophilia, thromboembolism, atherosclerosis, and the incidence and progression of carotid stenosis. At present, MRI SNP testing is mainly performed using costly nucleic acid analysis. The ratio between FSAP activity and antigen concentrations in citrated plasma has been used to assess the FSAP genotype.

Methods: This article describes the development of a prototype ELISA for the detection of the MRI FSAP alloenzyme, and its correlation to FSAP genotypes to assess whether a positive MRI FSAP ELISA result may be used as a surrogate marker for the presence of the MRI SNP.

Results: ELISA results were correlated with FSAP genotypes from 523 blood donors measured using PCR. Diagnostic sensitivity and specificity of the assay for determina-tion of the genotype were 100% (95% confidence interval [CI]: 93.36–100) and 99.79% (95% CI: 98.80–99.96), respectively. Maximum run-to-run, within-run, and total coefficients of variation were 7.8%, 7.9%, and 9.9%, respectively. No cross-reactivities with homologues of the MRI FSAP alloenzyme were observed. Test performance was not affected by typical interfering compounds.

Conclusions: The data demonstrate that an immunoassay applying antibodies specific to the MRI FSAP alloenzyme can provide sufficiently accurate detection of the MRI SNP. This will significantly simplify MRI FSAP testing, particularly in large cohorts.

Clin Chem Lab Med 2010;48:1745–9.
Quantification of coagulation factor XIII activity by a thio-NADH based assay using factor XIII immuno-depleted plasma as a diluent for calibration
Authors: Kappel Andreas , Stephan Sina , Christ Gerlinde , Pechmann Lena , Duwe Christa , Fischer Bodo , Hahn Martin , Althaus Harald , Ehm Matthias , Schwarz Herbert , Vitzthum Frank
Published: September 2010

Background: Accurate determination of factor XIII (FXIII) activity is crucial for replacement therapy. FXIII activity is typically determined using a coupled enzymatic reaction that measures nicotinamide adenine dinucleotide hydride (NADH) consumption at 340 nm.

Methods: Here, we describe the development of a prototype for a novel FXIII activity assay for detection at 405 nm by replacing NADH with thio-NADH, and the application of FXIII immuno-depleted plasma as a diluent for calibration.

Results: Performance data show up to two-fold lower susceptibility of the prototype assay to interferences from hemolyzed, icteric, and lipemic samples when compared to a NADH assay format. In addition, the use of FXIII immuno-depleted plasma as diluent for calibration improved recovery almost two-fold in the lower measurement range. The novel prototype assay correlates well with a conventional assay (r=0.98, y=0.99·x+2.17% FXIII, n=173).

Conclusions: The described prototype assay has the potential to (a) increase trueness of measurement of low levels of FXIII, (b) improve robustness due to reduction from interferences, and (c) can be used on a broad range of coagulation instruments due to its detection at 405 nm.

Clin Chem Lab Med 2010;48:1739–43.
Two Tests for Supplier Selection Based on Process Yield
Authors: Pearn W. L. , Liao Mou-Yuan , Wu Chien-Wei , Chu Yao-Tsung
Published: September 2010

Market share is highly corrected with customer satisfaction and business success; many companies increase their outsourcing level to keep their core competition. Supplier selection problems have become an important issue of production management. Process yield is a standard criterion in the manufacturing industry as a common measure on process performance. The index SPK provides an exact measure on the process yield for normal processes. However, most studies considered the assessment of index SPK for just one single supplier; the testing procedure for suppliers selection has not been done at present. Hence, the principal purpose of this research is to determine the more capable process between two competing suppliers. Two tests are presented based on SPK, and four bootstrap methods are used for obtaining the test statistics. By Monte Carlo simulations, performance comparisons of these methods are performed in terms of empirical size and selection power. Finally, a case on the color filter manufacturing process is investigated to demonstrate the applicability of the proposed method.
Developing a New Foresight Model for Future Technology Evaluation in Electric Vehicle Industry
Authors: Shiue Yih-Chearng , Lin Chun-Yueh
Published: September 2010

Scenario analysis (SA) is one of the methodologies utilized for forecasting issues within long-term events. Past researches have typically used SA to attain foresight into future issues that focus on a short-term time frame. Nevertheless, SA implies some weaknesses in that it is unable to define the transition between time states clearly and it cannot meaningfully explain how to forecast long-term uncertainty effectively and how to link present and future situations. Based on these weaknesses, we established a Markov SA (MASA) model that integrates the concept of vision, linking analysis planning, Markov chain, and SA so that we can improve the existing model for SA. The MASA model not only solves our insufficient information problem for a complete SA model but also classifies four categories for forecasting future events. The four categories that can confirm a future trend are (1) state of constancy, (2) state of disappearance, (3) state of change, and (4) state of uncertainty. This paper introduces the principles and application of the MASA model. A sample case study is given to explain how the MASA model can be applied.
Why Do We Pay? A National Survey of Investigators and IRB Chairpersons
Authors: Ripley Elizabeth , Macrina Francis , Markowitz Monika , Gennings Chris
Published: September 2010

The principle that payment to participants should not be undue or coercive is the consensus of international and national guidelines and ethical debates; however, what this means in practice is unclear. This study determined the attitudes and practices of IRB chairpersons and investigators regarding participant payment. One thousand six hundred investigators and 1900 IRB chairpersons received an invitation to participate in a web-based survey. Four hundred and fifty-five investigators (28.3%) and 395 IRB chairpersons (18.6%) responded. The survey was designed to gather considerations that govern payment determination and practical application of these considerations in hypothetical case studies. The survey asked best answer, multiple choice, and open text questions. Short hypothetical case scenarios where presented, and participants were asked to rate factors in the study that might impact payment and then determine their recommended payment. A predictive model was developed for each case to determine factors which affected payment. Although compensation was the primary reason given to justify payment by both investigators and IRB chairpersons, the cases suggested that, in practice, payment is often guided by incentive, as shown by the impact of anticipated difficulty recruiting, inconvenience, and risk in determining payment. Payment models varied by type of study. Ranges for recommended payments by both groups for different types of procedures and studies are presented.
Who's Doing the Math? Are We Really Compensating Research Participants?
Authors: Ripley Elizabeth , Macrina Francis , Markowitz Monika , Gennings Chris
Published: September 2010

Although compensation for expenses to participants in research projects is considered important and the primary reason for paying, there is no evidence to support that investigators and IRB members actually calculate participant cost. Payment recommendations for six hypothetical studies were obtained from a national survey of IRB chairpersons (N = 353) and investigators (N = 495). Survey respondents also recommended payment for specific study procedures. We calculated participant cost for the six hypothetical cases both by procedures and by time involvement. A large percentage recommended only token payments for survey, registry, and medical record review studies. Most chose payment for pharmaceutical studies but the recommended payment did not compensate for calculated costs. Results suggest that compensation and reimbursement as the primary reasons for paying research participants may not match actual practice.
The Importance of Organizational Justice in Ensuring Research Integrity
Authors: Martinson Brian C. , Crain A. Lauren , De Vries Raymond , Anderson Melissa S.
Published: September 2010

The professional behavior of scientists, for good or ill, is likely associated with their perceptions of whether they are treated fairly in their work environments, including their academic department and university and by relevant regulatory bodies. These relationships may also be influenced by their own personal characteristics, such as being overcommitted to their work, and by the interactions between these factors. Theory also suggests that such associations may be mediated by negative or positive affect. We examined these issues using data from a national, mail-based survey administered in 2006 and 2007 to 5,000 randomly selected faculty from biomedical and social science departments at 50 top-tier research universities in the United States. We found that perceptions of justice in one's workplace (organizational justice) are positively associated with self-report of “ideal” behaviors and negatively associated with self-report of misbehavior and misconduct. By contrast, researchers who perceive that they are being unfairly treated are less likely to report engaging in “ideal” behaviors and more likely to report misbehavior and misconduct. Overcommitment to one's work is also associated with negative affect and interacts with perceptions of unfair treatment in ways that are associated with higher self-report of misbehavior. Thus, perceptions of fair treatment in the work environment appear to play important roles in fostering—or undermining—research integrity.
Glad You Asked: Participants' Opinions of Re-Consent for DbGap Data Submission
Authors: Ludman Evette J. , Fullerton Stephanie M. , Spangler Leslie , Trinidad Susan Brown , Fujii Monica M. , Jarvik Gail P. , Larson Eric B. , Burke Wylie
Published: September 2010

No consensus exists about when researchers need additional participant consent (re-consent) to submit existing data to the federal database of Genotypes and Phenotypes (dbGaP). Re-consent for submission of their data to dbGaP was sought from 1,340 study participants, 1,159 (86%) of whom agreed. We invited the first 400 of those who agreed to complete a telephone survey about their reasoning for their consent decision and their satisfaction with the re-consent process; 365 participants completed the survey. Respondents reported that it was very (69%) or somewhat (21%) important that they were asked for their permission. Many respondents considered alternatives to consent, such as notification-only or opt-out, to be unacceptable (67% and 40%, respectively). These results suggest that re-consent for dbGaP deposition may be advisable in certain cases to anticipate and honor participant preferences.
Newborn TSH concentration and its association with cognitive development in healthy boys
Authors: Freire Carmen , Ramos Rosa , Amaya Esperanza , Fernández Mariana F , Santiago-Fernández Piedad , Lopez-Espinosa Maria-Jose , Arrebola Juan-Pedro , Olea Nicolas
Published: September 2010

Objective

An association between thyroid function during pregnancy or infancy and neurodevelopment in children has been demonstrated. We aimed to investigate whether newborn TSH concentrations are related to subsequent neurocognitive development.

Design

We conducted a longitudinal study on 178 children from a general population birth cohort in Granada (Spain) born in 2000–2002.

Methods

TSH concentrations were measured in umbilical cord blood, and cognitive functions were assessed at 4 years of age using the McCarthy's scales of children's abilities (MSCA). Organochlorine (OC) compound concentrations and the combined oestrogenicity (total effective xeno-oestrogenic burden (TEXB)) were also determined in the placentae.

Results

Mean newborn TSH was 3.55 mU/l (range=0.24–17 mU/l). In multivariate regression analyses, adjusting for maternal and child characteristics, higher newborn TSH concentrations showed a decrease of 3.51 and 3.15 points on the MSCA general cognitive and executive function scores respectively and were associated with a higher risk of scoring below the 20th percentile (P20) on the quantitative score (odds ratio (OR)=2.64). Children with TSH in the upper quartile (4.19–17.0 mU/l) were at higher risk of scoring <P20 on span memory (OR=5.73), whereas children with TSH in the second quartile (2.05–2.95 mU/l) were at lower risk of scoring <P20 on the verbal scale (OR=0.24). Neonatal TSH status was also associated with general cognitive and executive function outcomes when controlling for prenatal exposure to OCs or placental TEXB.

Conclusions

Newborn thyroid hormone status expressed by TSH in cord blood may adversely affect later cognitive function. A more thorough screening for neonatal thyroid deficiency is warranted.
Effect of weight reduction on insulin sensitivity, sex hormone-binding globulin, sex hormones and gonadotrophins in obese children
Authors: Birkebæk N H , Lange A , Holland-Fischer P , Kristensen K , Rittig S , Vilstrup H , Handberg A , Gronbaek H
Published: September 2010

Objective

Obesity in men is associated with reduced insulin sensitivity and hypoandrogenism, while obesity in women is associated with reduced insulin sensitivity and hyperandrogenism. In children, the effect of obesity and weight reduction on the hypothalamo-pituitary–gonadal axis is rarely investigated. The aim of the present study was to investigate the effect of weight reduction in obese Caucasian children on insulin sensitivity, sex hormone-binding globulin (SHBG), DHEAS and the hypothalamo-pituitary–gonadal axis.

Methods

One hundred and sixteen (65 females) obese children with a median age of 12.3 (7–15) years were examined before and after a 10-week stay at a weight loss camp. Examination included anthropometry and fasting blood samples measuring plasma glucose, serum insulin, SHBG, DHEAS, testosterone, 17β-oestradiol, FSH and LH.

Results

Body mass index (BMI) decreased (P<0.01), insulin sensitivity and SHBG increased (P<0.01), independent of gender and puberty. The changes in insulin sensitivity and the changes in SHBG correlated significantly (P<0.01) independent of gender, puberty and the changes in BMI. Testosterone increased in boys (P<0.01) and tended to decrease in girls (P=0.05, in girls after menarche (P=0.03)). FSH increased in boys and girls. LH increased in boys and was unchanged in girls.

Conclusions

During weight loss, insulin sensitivity and SHBG increased significantly in obese children, and the changes in insulin sensitivity and the changes in SHBG correlated significantly independent of gender, puberty and the changes in BMI. There was sexual dimorphism in the changes of testosterone, with the changes in boys towards increased virilisation and the changes in girls towards less virilisation.
Effects of light and nutrients on different germination phases of the Cosmopolitan moss Bryum argenteum Hedw. (Bryaceae)
Authors: Silva Adaíses Simone Maciel da , Pôrto Kátia Cavalcanti , Simabukuro Eliana Akie
Published: September 2010

The influence of light and nutrients on the different germination phases of Bryum argenteum spores was studied. The following treatments were used: distilled water and nutrient solution under light (12 h) and continuous darkness. The spores germinated when exposed to light, independent of both medium used. Under darkness, the spores swelled and became chlorophyllous. In the presence of nutrient solution, the germination occurred earlier (after two days) when compared to the distilled water (after more than three days). Nutrients were needed to complete the last germination phase in the majority of spores and to provide the protonemal growth.
Nictemeral variations for pacu Caranha, Piaractus mesopotamicus (Holmberg, 1887) culture in single - phase
Authors: Barreto Luiz Eduardo Guimarães de Sá , Igarashi Marco Antonio , Hayashi Carmino
Published: September 2010

Studies related to nictemeral variation were executed in a fish growing pond, during all the seasons of the year, collecting data for dissolved oxygen; temperature; pH and electrical conductivity at the feeding channel on pond's surface, bottom and at streamlet bed. The results showed that Autumn was the season which had the lowest values of water temperature, the interval points, during Spring time, had superior average values of temperature when compared to the ones that were observed at external points. The lowest and highest index of pH were during Autumn season. The electrical conductivity didn't show significant differences during Autumn season. The samples obtained from the streamlet had very high significant differences with the samples of fish pond inner part, showing that there was an influence on external environment from the effluent which came from the inner part of the fish pond on limnology variables.
Elevated Plasma Homocysteine Levels in Chronic Periodontitis: A Hospital‐Based Case‐Control Study
Authors: Joseph Rosamma , Nath Sameera G. , Joseraj M. G.
Published: September 2010

Background: Plasma homocysteine (Hcy), a novel risk factor for cardiovascular disease, has been found to be increased in inflammatory diseases, such as rheumatoid arthritis. Our study investigates the association between chronic periodontitis and plasma Hcy.

Methods: This case‐control study involves 85 age‐ and sex‐matched subjects with chronic periodontitis and 91 healthy controls. Patients were grouped into moderate and severe periodontitis. Plaque index, calculus component of simplified oral hygiene index, and modified gingival index were recorded. Body mass index, fasting blood sugar, total cholesterol, triglycerides, high‐density lipoprotein, low‐density lipoprotein, very‐low‐density lipoprotein, and plasma Hcy were also assessed.

Results: Case and control groups had similar levels of fasting blood sugar, lipid profile, and body mass index. The mean plasma Hcy was found to be 19.22 ± 8.27 and 10.27 ± 2.50 μmol/L for cases and controls, respectively. A significant elevation in plasma Hcy levels was observed in cases (P <0.05). No significant differences were observed in plasma Hcy levels between moderate and severe chronic periodontitis (P = 0.722).

Conclusions: Elevated levels of plasma Hcy were observed in patients with chronic periodontitis. Future research should be directed on the effect of periodontal therapy on plasma Hcy levels.
Stability of Contour Augmentation and Esthetic Outcomes of Implant‐Supported Single Crowns in the Esthetic Zone: 3‐Year Results of a Prospective Study With Early Implant Placement Postextraction
Authors: Buser Daniel , Wittneben Julia , Bornstein Michael M. , Grütter Linda , Chappuis Vivianne , Belser Urs C.
Published: September 2010

Background: Early implant placement is one of the treatment options after tooth extraction. Implant surgery is performed after a healing period of 4 to 8 weeks and combined with a simultaneous contour augmentation using the guided bone regeneration technique to rebuild stable esthetic facial hard‐ and soft‐tissue contours.

Methods: In this prospective study, 20 patients were treated with an implant‐born single crown and followed for 3 years. Clinical, radiologic, and esthetic parameters were recorded to assess treatment outcomes.

Results: At the 3‐year examination, all 20 implants were successfully integrated, demonstrating ankylotic stability and healthy peri‐implant soft tissues as documented by standard clinical parameters. Esthetic outcomes were assessed by the pink esthetic score (PES) and white esthetic score (WES) and confirmed pleasing results overall. WES values were slightly superior to PES values. Periapical radiographs showed minimal crestal bone loss around used bone‐level implants with a mean bone loss of 0.18 mm at 3 years. Only two implants revealed bone loss between 0.5 and 1.0 mm. One of these implants had minor mucosal recession <1.0 mm.

Conclusions: This prospective study evaluates the concept of early implant placement and demonstrated successful tissue integration for all 20 implants and stable bone‐crest levels around implant–abutment interfaces according to the platform‐switching concept. The midterm 3‐year follow‐up revealed pleasing esthetic outcomes and stable facial soft tissues. The risk of mucosal recession was low, with only one patient showing minor recession of the facial mucosa. These encouraging results need to be confirmed with a 5‐year follow‐up examination.
An Experimental Investigation of Interactions Between Supercritical CO2, Aspheltenic Crude Oil, and Reservoir Brine in Carbonate Cores
Authors: Zekri Abdulrazag Y. , Shedid Shedid A. , Almehaideb Reyadh A.
Published: September 2010

Asphaltene precipitation and rock dissolution can significantly hinder the success of carbon dioxide flooding of asphaltenic crude in carbonate formation. It is essential during CO2 flooding when both processes exist to study separately the effect of each phenomenon on the flooding process.

Core flooding experiments under high pressure and temperature conditions (250 °F, and 4000 psia) were conducted to evaluate each phenomenon separately. Actual cores representing different areas of carbonate oil field and actual fluids (crude oil and brine) were used to evaluate the interaction between CO2, rock and fluids. Asphaltene content of the produced crude oil, water and mineralogical rock analysis, and pores micro-photos were performed to evaluate the effect of SC CO2 flood on the petrophysical characteristics of the limestone cores. Results indicate that the amount of damage depends on the fabric of the rocks, salinity of the brine, core permeability and damage is due to interaction between CO2 and rock. Fluids assessment should be conducted to different areas of the field.
16S rRNA: Genes Comparative Analysis of Microbial Communities in Oil Reservoir with Nutrients Injection by Terminal Restriction Fragment Length Polymorphism Method
Authors: Haiying Cheng , Weidong Wang
Published: September 2010

A quantitative molecular method was developed for rapid analysis of microbial community structure in oil reservoir environments. For monitoring the dynamic of microbial community under simulated oil reservoir conditions, the effect of nutrients injection on the structure of oil reservoir microbial community was investigated by the analysis of the amplified 16S rRNA genes applying a cultivation- and clone-independent molecular method―terminal restriction fragment length polymorphism (T-RFLP). Using bacterial and archaeal primer pairs in which forward primers were fluorescently labeled at the 5’ end, 16S rRNA genes were amplified from total community DNA by polymerase chain reaction (PCR). The PCR products was digested with restriction endonucleases RsaI plus MspI, the 5’ labeled terminal restriction fragments was then efficiently separated by capillary gel electrophoresis and sensitively detected by laser-induced fluorescence detector for determining the length and abundance of each unique T-RF. Results from T-RFLP pattern comparisons between samples with different incubation time showed that number and abundance of T-RFs were significantly increased after incubation and structures of microbial community were distinctly different. This indicated that species and abundances of microorganisms in oil reservoir were under a dynamic transition after nutrients injection. Totally, results demonstrated that T-RFLP is a powerful tool for assessing the diversity of oil reservoir microbial community, instantaneous monitoring and successively following the dynamic of microbial community in studies on EOR using indigenous microorganisms. In field test design, T-RFLP method could be used to optimize nutrient systems and to evaluate contribution of different microbial population to EOR.
Alteration of Sand Wettability by Corrosion Inhibitors and Its Effect on Formation of Sand Deposits
Authors: Gulbrandsen E. , Pedersen A.
Published: September 2010

The surface chemical properties of solids particles strongly influence their behavior in multiphase flow, e.g. their tendency to be transported by the oil or water phase, or stick to the oil-water interfaces, or their tendency to aggregate. The behavior of the solid particles may influence various phenomena such as emulsion stability, oil-water separation, sedimentation of solids in a pipeline, corrosion under deposits, and erosion. The present paper focuses on the behavior of quartz sand in a simple oil-water system in presence of a model corrosion inhibitor compound; cetyltrimethylammonium bromide (CTAB). Refined, low-aromatic oil was used in the tests. Zeta-potential measurements on crushed sand particles demonstrated that CTAB adsorbed onto the sand particles. Wettability of the sand surface was measured by capillary rise velocity of water and oil in sand columns. Adsorption of the model corrosion inhibitor changed the sand surface from preferentially water wetting to intermediate wetting. Flow behavior of the sand was studied in stirred beakers with brine, oil and sand. Addition of corrosion inhibitor caused the sand to stick to the oil-water interface. Furthermore, the sand grains aggregated to form sticky deposits that contained hydrocarbon phase. The results demonstrate the effect of surfactants on the formation of deposits, and shows that surface-active chemicals like corrosion inhibitor may significantly affect the behavior of sand in multiphase flow. These findings are important with respect to testing procedures where solids are involved. Such chemicals should thus be included in studies of solids behavior in multiphase flow. The results may furthermore contribute to improved understanding of under-deposit corrosion.
Well Construction on Wireline
Authors: Karlsen Ole Eddie , Lothe Guthorm , Aasland Stig
Published: September 2010

A further evolution of wireline intervention technique has emerged allowing mechanical manipulation in horizontal wells using a combination of Wireline Stroker and field proven Wireline Tractor technology - best described as Well Construction on wireline in a highly deviated well.

This technology represents a cost-efficient method for setting and retrieving of specific downhole hardware (i.e. plugs and straddles) as a resource-efficient alternative to existing technologies.

This paper will present the following case history and the benefits of the operation, particularly in deviated wells, where tractor technology in combination with the Wireline Stroker exemplify the advantages of this technology.

In a well offshore Norway, producing since 1995, completed with 2 Sliding Side Doors (SSD) to control zone production, attempts had been made to close both SSD's in October 2003, but only the upper SSD was possible to close. A two-piece straddle was sat above the lower SSD, which however showed no change in production. PLT results showed an internal leakage in straddle and tubing; straddle was therefore retrieved in February 2006 and the well temporarily plugged.

Later in 2006, it was decided to perform a new intervention in order to remedy the situation and a Tractor/Stroker combination was considered optimal for performing the operation, as an alternative to a Coiled Tubing operation.
Challenges in Work Over Jobs During In-Situ Combustion Process in India—A Field Experience
Authors: Bhattacharya R. N. , Chattopadhyay S. K.
Published: September 2010

This paper describes the problems encountered during the different types of work over jobs viz. removal of artificial lift, optimization of the perforation interval suited to the process, cement squeeze jobs in the gas out wells, servicing of SRP, repair of gravel pack etc and their remedial solutions. Work over job is also required during planned conversion of injectors from dry phase to wet phase.

It has been observed that the time interval between the dry and wet phase is very crucial. The optimization of the time interval for conversion of the phases (Dry to Wet) is very much essential to avoid the high corrosion in tubing's, thermocouple wire clamps and burner assembly which results a long fishing job during work over operations, cost and time over run. The experiences gained in these jobs form the basis of this paper.
Rigless Abrasive Perforating and Fracturing in Horizontal Tight Gas Wells
Authors: Schnaidler G. , Naegel M. , Marozzini D. , Liberatore F. , Valdivia M.
Published: September 2010

This particular field is a mature gas field. It produces gas and condensates. The reservoir consists of low permeability sandstones deposited in a fluvio-tidal to littoral environment. The last one can be classified as "Tight Gas" reservoir, which requires fracture stimulation treatments.

The reservoir characteristics led to think about non-conventional designs of the wells and their completions. The approach of completing a ca 1700 m TVD / 3000 m MD cemented horizontal well was the challenge.

As a result of this process, new technologies were applied for the first time in the region. Among others, abrasive perforating using state of the art coiled tubing tools; multiple zones stimulation, creating orthogonal fractures in the horizontal section; the use of composite frac plugs and special sand bridge plugs for zonal isolation. On the other hand, the analysis and the inherent operational learning curve led to important logistic and economic benefits, ie a rig-less completion operation.

One of the final steps of this process, the completion of the first well, was carried out on December 2009. Six frac stages were successfully performed using sand jetting perforating technology, composite bridge plugs, enhanced proppant bridge plugs and ultra light weight proppant, among others.

This paper summarizes the process of selecting the best options for completion sizes for an optimized production, CT tools and strings, the design, operational planning and results of the application of the above described completion techniques.
Pressure Analysis of a Well with an Inclined Asymmetric Hydraulic Fracture Using Type Curves
Authors: Habte Azeb Demisi , Dinh Anh V. , Tiab Djebbar
Published: September 2010

Hydraulic fracturing is an effective well stimulation technique which is introduced in the 1950s and widely used in the oil and gas industry. Most of the works about hydraulic fracturing assumed that the fracture is symmetric and either vertical or horizontal. But, several field and laboratory observations show very complex fractures, inclined, multi-segmented, asymmetric, and multiple fractures.

The purpose of this study is to investigate the pressure behaviour of a uniform flux hydraulic fracture which is both inclined and asymmetric. This objective is achieved by using transient pressure and pressure derivative plots. Three cases are investigated; (a) the fracture is asymmetric only along the horizontal direction (X-axis), (b) the fracture is asymmetric only along the lateral direction (Y-axis), and (c ) the fracture is asymmetric along both horizontal and lateral directions.

Three flow regimes, Linear Flow Regime, Early-Radial Flow Regime, and Pseudo-Radial Flow Regime are observed when the asymmetry is not significant and for small θw and hD. As the asymmetry increases the behaviour the fracture also shows changes. For a fracture with high asymmetry, Bi-radial Flow Regime is observed in addition to the above flow regimes. As the asymmetry becomes significant the uniform flux fracture solution shows similar behaviour to infinite conductivity fracture.

Type curve matching technique was developed in this study using pressure and pressure derivative curves. This type curve matching technique can be used to obtain the following reservoir parameters: fracture half length, inclination angle, formation permeability and the pseudo-skin factor, caused by fracture inclination.
Investigating the Use of Nanoparticles in Enhancing Oil Recovery
Authors: Onyekonwu Mike O. , Ogolo Naomi A.
Published: September 2010

This paper is aimed at studying the ability of three different polysilicon nanoparticles (PSNP) to enhance oil recovery. Changing rock wettability is the target because wettability is a primary factor that affects recovery efficiency. The experiments conducted centered on laboratory coreflooding using two kinds of oil, brine and polysilicon nanofluids on water wet rocks obtained from the Niger Delta. The three kinds of PSNP used for this study were lipophobic and hydrophilic PSNP (LHPN), hydrophobic and lipophilic PSNP (HLPN) and neutrally wet PSNP (NWPN).

The results obtained indicate that NWPN and HLPN are good enhanced oil recovery (EOR) agents in water wet formations. Two mechanisms through which oil recovery is enhanced using NWPN and HLPN are change of rock wettability and reduction of interfacial tension by the improved quality of ethanol, the dispersing agent. Thus NWPN and HLPN dispersed in ethanol are recommended for use in EOR for water wet formations. LHPN which make already water wet rocks strongly water wet yield poor recovery factors indicating that its use for EOR should be restricted to oil wet formations.
An Applied High Temperature Sand Control Well Completion Technique for Horizontal Wells
Authors: Ruiyi Xu , Zhiqi Zhou , Xu Zhang
Published: September 2010

In last years, a number of horizontal wells has been drilled in Shengli Oilfield for increasing recoverable reserves, advancing economic benefits of new oilfield and developing previous unrecoverable resources, including extra-heavy oil in deep reservoir. Due to most of the heavy oil reservoirs are unconsolidated, it is needed to adopt the high temperature sand control completion technique to meet the requirements of the thermal recovery.

The high temperature pre-pack screen was used. It is a successful method for sand control, but the gravel liners breakdown easily while go through the bending intervals of the wells, thus, the effects and life of the liners will be decreased. In this case, a new metal-fiber screen was developed and used in 12 wells with different geological conditions. The success ratio for sand control reached 100%, and the oil production of individual wells achieved the expected volume. This method can be used in wells of 4265∼4921 ft depth and under high temperature more than 665°F.

This paper describes the completion and sand control methods for horizontal wells used in Shengli Oilfield with emphasis on the study and field application of the metal-fiber screen.
Practical and Robust Simulation for Anisotropic Reservoirs
Authors: Murakami Yuji , Namba Takao , Yamazaki Noboru
Published: September 2010

Significant areal heterogeneity and anisotropy are recognized in some fields, i.e. naturally fractured basement reservoirs in offshore South East Asia. In conventional Cartesian five point finite difference reservoir simulators, the coordinate system must coincide with the principal axes of permeability to eliminate tensor cross terms. As the simulators incorporating full tensor permeabilities are still not commercially available in the industry, a practical approach is necessary to represent complex and anisotropic reservoirs. In this paper, a modified grid scheme and interface permeability calculations are presented based on our in-house Voronoi-based flexible reservoir simulator (VERDI-3D). Numerical tests showed that the directional advances in pressure transients and water fronts can be represented by the proposed "pseudo-octagonal" grid system.
HSE Tools: Which Tools are Appropriate?
Authors: Hudson P. T. W. , van der Graaf G. C. , Parker D. , Lawton R. , Verschuur W. L. G.
Published: September 2010

A study into different HSE tools reveals why some tools may be better than others. Tools can be structured along two dimensions. One dimension loads on how much a tool is a managerial, long-term aid, providing information for improvement. The other dimension loads on the extent to which a tool is applicable at the workforce level, helping to manage immediate hazards and make current practices better. The appropriateness and acceptability of tools is also strongly determined by the company's safety culture and the national culture.

The analysis of why tools work found four crucial dimensions:

Proactive vs Reactive – Reactive tools are more appropriate in early stages, proactive tools are needed and effective only when the safety culture is sufficiently advanced. Hazard Recognition vs Hazard management – Some tools help people recognise the presence of their hazards, other tools help them to manage and prioritise. Behaviour vs Attitude – Early stages of safety culture require behaviour to lead attitude change; later stages are characterised by attitudes leading behaviour. Reward vs Punishment – Disciplinary methods have their place in abolishing specific bad practices, rewards help cultivate generally good practices but are easy to misapply.

Continuous striving for improvement creates a tension between how people think and feel about HSE and how they actually behave. This tension can be structured by the right tools to generate real improvement. Internal or mental models of what HSE management is about can only develop slowly. Proactive approaches rely on such models as positive attitudes become internalised.
Re-Development Issues and Challenges for a Very Old Oil Field, Masjed-I-Suleyman, South West Iran
Authors: Nguyen Hanh T. , Kelly Roy T. , Sodero Dario , Niakan Mohammad R.
Published: September 2010

This paper outlines the formulation of a re-development plan for the oldest producing field in the Middle East, Masjed-I-Suleyman, discovered in 1908 in the South West of the Islamic Republic of Iran and put into production in 1911. The field location is shown in Figure 1.

The difference between the volume and type of data acquired in 1908 versus that acquired now is in itself one of the greatest challenges to overcome when undertaking such a study. The field does not have a virgin reservoir fluid sample, nor early pressure measurements, or any measurement of produced gas volumes. However, these are key parameters which must be tested rigorously in the reservoir models.

The redevelopment plan revolves around a comprehensive reservoir study of the Asmari formation, a complex, fractured carbonate reservoir. The objectives of this study - the first on the field - are to gain a better understanding of the reservoir and its production and pressure performance over nearly a century and to develop a plan for further developing the field by drilling new vertical and horizontal wells. Reservoir characterization provides input data for a full field, dual porosity simulation model, which in turn verifies the input data. Complicated reservoir pressure and production history matches were successfully obtained to provide the basis for future production forecasts. Re-injection of gas and water to maintain reservoir pressure was also reviewed. Sensitivity studies on different locations for the new wells shows that a substantial incremental recovery can be recovered. Apart from the inherent geological complexity, the project faced tremendous data challenges such as the first field report having been written some 37 years after the start of production.
A Review of Elementary School-Based Substance Use Prevention Programs: Identifying Program Attributes
Authors: Hopfer S. , Shin Y. , Davis D. , Elek E. , Kam J. A. , Hecht M. L.
Published: September 2010

This article takes a systematic approach to reviewing substance use prevention programs introduced in elementary school (K-6th grade). Previous studies evaluating such programs among elementary school students showed mixed effects on subsequent substance use and related psychosocial factors. Thirty published evaluation studies of 24 elementary school-based substance use prevention programs were reviewed. The study selection criteria included searching for program evaluations from 1980 to 2008. Among 27 evaluation studies that examined program effects on substance use, 56% ( n = 15) found significant decreases. In addition, programs most often demonstrated effects on increasing negative substance use attitudes, increasing knowledge, decreasing perceptions of prevalence rates (i.e., descriptive norms), and improving resistance skills. These results have implications for the appropriateness and value of introducing substance use prevention programs to youth in elementary school.
The Prevalence of Evidence-Based Substance Use Prevention Curricula in the Nation's Elementary Schools
Authors: Hanley Sean M. , Ringwalt Chris , Ennett Susan T. , Vincus Amy A. , Bowling J. Michael , Haws Susan W. , Rohrbach Louise A.
Published: September 2010

Current guidelines for school-based substance use prevention suggest that prevention efforts should begin in elementary grades, before students begin using substances. Previous research suggests, however, that the use of evidence-based curricula in these grades may be low. Using a 2005 survey of public school districts in the United States that include elementary grades ( n = 1563), we assessed the prevalence of elementary curricula use, particularly those designated as evidence-based. We found that although 72% of districts administer a substance use prevention curriculum to their elementary students, only about 35% are using one that is evidence-based and only about 14% are using an evidence-based curriculum more so than any other prevention curriculum. We present prevalence estimates for specific evidence-based curricula and conclude by discussing possible reasons for and implications of our findings.