bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determining Pore Level Mechanisms of Alkaline Surfactant Polymer Flooding using a Micromodel
Authors: AlDousary Salem 
Published: January 2013

Abstract
Primary recovery methods such as water flooding recover as much as 50% of the original oil in place and therefore end up leaving remaining oil that is less likely to be produced behind in the reservoir. In fractured reservoirs, the recovery efficiency is even lower as water prefers to channel leaving a considerable amount of uswept reservoir. New techniques have been introduced in order to access this unrecoverable potential; these techniques are assembled in what is called Enhanced Oil Recovery (EOR). Enhanced oil recovery processes play a major role in increasing the recovery efficiency and extracting the inaccessible oil that has been trapped in a reservoir. One type of enhanced oil recovery applicable to waterflood reservoirs is alkali surfactant polymer (ASP) flooding. Polymer flooding (PF) and alkaline/surfactant/polymer (ASP) flooding have been known and in practice for more than 20 years. These processes have shown successful results during large-scale implementations in China, for instance. ASP flooding is a form of chemical enhanced oil recovery (EOR) that allows operators to extend reservoir pool life and extract incremental reserves currently inaccessible by conventional EOR techniques such as water flooding. The combination of all three chemicals is synergetic. The surfactant is ultimately used to lower the interfacial tension between the oil and the injected water. The alkali reacts with the acidic portion of oil to produce in-situ soap (surfactant) and the polymer increases the injection water viscosity to reduce the possibility of channeling and viscous fingering during the process. The objective of this study is to grasp a better understanding of the mechanisms of ASP flooding will by conducting several experiments in carbonate micromodels. A micromdel is a two dimensional porous medium created by etching a pore network into silicon. Pore-level mechanisms are observed directly using a micromodel. The challenge is to understand how the combination of alkali, surfactant, and polymer allows us to best access the matrix and efficiently sweep the oil. Therefore, a screeting study was conducted to evaluate diverse surfactants of concentrations ranging from 0.5 to 5.0 % by measuring the interfacial tensions in order to select one compatible with light crude oil (27°API). Both secondary and tertiary flooding of the ASP slug was tested at realistic flood rates of 0.1 m/day Darcy velocity. Greater flow rates were later attempted to maximize recovery, within the reasonable pressure range that the micromdel can handle, to maximize recovery. The results are presented in the form of image analysis of microscopic pictures taken at different locations to estimate the oil recovery. The ASP displacement experiments conducted yields reasonable improvement of recovery for all cases.
Simplified Modelling of Downhole Pressure Surges for Bingham Fluids in Tripping Operations
Authors: Gjerstad Kristian 
Published: January 2013

Abstract
Flow of Bingham fluids in plane Couette-Poiseuille flow is studied. We present a set of analytically flow equations for flow between parallel plates/slots in a most compact form, and use this set as a basis for developing simpler flow equations. The new equations approximate the full analytical solution over a wide range of flow rates, and they are explicit in the frictional pressure gradient. Thus, they are well suited for application in fast dynamic flow models, where the implicit analytical solution is not applicable. We illustrate the application of the new equations in a dynamic model of the tripping operation in oil well drilling. The accuracy is shown to be absolutely satisfactory. Such a model may be coupled with control system theory and parameter estimation techniques, which enables automatic pressure control and adaptation of unknown model parameters.
Pointwise definable models of set theory
Authors: Hamkins Joel David , Linetsky David , Reitz Jonas 
Published: January 2013

AbstractA pointwise definable model is one in which every object is definable without parameters. In a model of set theory, this property strengthens V = HOD, but is not first-order expressible. Nevertheless, if ZFC is consistent, then there are continuum many pointwise definable models of ZFC. If there is a transitive model of ZFC, then there are continuum many pointwise definable transitive models of ZFC. What is more, every countable model of ZFC has a class forcing extension that is pointwise definable. Indeed, for the main contribution of this article, every countable model of Gödel-Bernays set theory has a pointwise definable extension, in which every set and class is first-order definable without parameters.
25-Hydroxyvitamin D in Obese Youth Across the Spectrum of Glucose Tolerance From Normal to Prediabetes to Type 2 Diabetes
Authors: de las Heras Javier , Rajakumar Kumaravel , Lee SoJung , Bacha Fida , Holick Michael F. , Arslanian Silva A. 
Published: January 2013

OBJECTIVE
To 1) determine if plasma 25-hydroxyvitamin D (25[OH]D) concentrations differ among obese youth with normal glucose tolerance (NGT) versus prediabetes versus type 2 diabetes and 2) assess the relationships between 25(OH)D and in vivo insulin sensitivity and β-cell function in this cohort.

RESEARCH DESIGN AND METHODS
Plasma 25(OH)D concentrations were examined in banked specimens in 9- to 20-year-old obese youth (n = 175; male 42.3%, black 46.3%) (NGT, n = 105; impaired glucose tolerance [IGT], n = 43; type 2 diabetes, n = 27) who had in vivo insulin sensitivity and secretion measured by hyperinsulinemic-euglycemic and hyperglycemic clamp techniques and had an assessment of total body composition and abdominal adiposity.

RESULTS
The mean age and BMI of the subjects were 14.3 ± 2.1 years and 35.7 ± 5.6 kg/m2, respectively. BMI, plasma 25(OH)D, and the proportion of vitamin D–deficient and –insufficient children did not differ across the three groups. Furthermore, there was no association between 25(OH)D and in vivo insulin sensitivity or β-cell function relative to insulin sensitivity (disposition index) in all groups combined or in each group separately.

CONCLUSIONS
Our data in obese youth show 1) no differences in plasma 25(OH)D concentrations across the glucose tolerance groups and 2) no relationship between 25(OH)D and in vivo insulin sensitivity and β-cell function relative to insulin sensitivity in any of the groups. It remains uncertain if enhancement of the vitamin D status could improve pathophysiological mechanisms of prediabetes and type 2 diabetes in obese youth.
Prevalence of Morphometric Vertebral Fractures in Patients With Type 1 Diabetes
Authors: Zhukouskaya Volha V. , Eller-Vainicher Cristina , Vadzianava Volha V. , Shepelkevich Alla P. , Zhurava Irina V. , Korolenko Galina G. , Salko Olga B. , Cairoli Elisa , Beck-Peccoz Paolo , Chiodini Iacopo 
Published: January 2013

OBJECTIVE
Several studies showed low bone mineral density (BMD) and elevated risk of symptomatic fractures in patients with type 1 diabetes (T1D). To our knowledge, there has been no investigation on the prevalence of asymptomatic vertebral fractures (VFx) in T1D. In the current study, we assessed BMD and the prevalence of VFx in T1D.

RESEARCH DESIGN AND METHODS
We evaluated 82 T1D patients (26 males and 56 females, aged 31.1 ± 8.6 years, BMI 23.5 ± 3.3 kg/m2, disease duration 12.8 ± 8.3 years) and 82 controls (22 females and 60 males, aged 32.9 ± 5.8 years, BMI 23.9 ± 4.8 kg/m2). Spinal and femoral BMD (as Z-score, Z-LS and Z-FN, respectively) and the prevalence of VFx were evaluated by dual X-ray absorptiometry.

RESULTS
T1D patients had lower Z-LS and Z-FN than controls (−0.55 ± 1.3 vs. 0.35 ± 1.0, P &lt; 0.0001, and −0.64 ± 1.1 vs. 0.29 ± 0.9, P &lt; 0.0001, respectively) and a higher prevalence of VFx (24.4 vs. 6.1%, P = 0.002). Age, diabetes duration, age at diabetes manifestation, glycosylated hemoglobin, Z-LS, Z-FN, and the prevalence of chronic complications were similar for patients with and without VFx. In the logistic regression analysis, the presence of VFx was associated with the presence of T1D but not with lumbar spine BMD. Whereas moderate or severe VFx was associated with low lumbar spine BMD in the whole combined group of T1D patients and controls, there was no association between moderate or severe VFx and lumbar spine BMD in the T1D group.

CONCLUSIONS
T1D patients have low BMD and elevated prevalence of asymptomatic VFx, which is associated with the presence of T1D independently of BMD.
Identification of Minimal Clinically Important Difference Scores of the PedsQL in Children, Adolescents, and Young Adults With Type 1 and Type 2 Diabetes
Authors: Hilliard Marisa E. , Lawrence Jean M. , Modi Avani C. , Anderson Andrea , Crume Tessa , Dolan Lawrence M. , Merchant Anwar T. , Yi-Frazier Joyce P. , Hood Korey K. ,   for the SEARCH for Diabetes in Youth Study Group
Published: January 2013

OBJECTIVETo establish minimal clinically important difference (MCID) scores representing the smallest detectable change in quality of life (QOL), using the Pediatric Quality of Life Inventory (PedsQL) Generic Core and Diabetes Module among youth with diabetes and their parents, and to identify demographic and clinical correlates of QOL change over 1 year.RESEARCH DESIGN AND METHODSParticipants in the SEARCH for Diabetes in Youth Study aged &gt;5 years and parents of youth aged &lt;18 years completed PedsQL surveys at their initial and 12-month study visits. MCIDs for each PedsQL module were calculated using one standard error of measurement. Demographic and clinical characteristics associated with QOL change were identified through multiple linear and logistic regression analyses.RESULTSThe sample comprised 5,004 youth (mean age, 12.5 ± 4.7 years; mean diabetes duration, 3.4 ± 3.7 years). Of 100 possible points, PedsQL total score MCIDs for youth with type 1 and type 2 diabetes, respectively, were Generic Core, 4.88, 6.27 (parent) and 4.72, 5.41 (youth); Diabetes Module, 4.54, 6.06 (parent) and 5.27, 5.96 (youth). Among 1,402 youth with a follow-up visit, lower baseline QOL, male sex, private insurance, having type 1 diabetes, longer diabetes duration, and better glycemic control predicted improvements in youth- and parent-reported PedsQL total scores over 1 year. Clinically meaningful (≥1 MCID) improvements in total score for at least one PedsQL module were predicted by private insurance, lower BMI, and lower A1C at baseline.CONCLUSIONSThese diabetes-specific reference points to interpret clinically meaningful change in PedsQL scores can be used in clinical care and research for youth with type 1 and type 2 diabetes.
Prospective Association Between Inflammatory Markers and Progression of Coronary Artery Calcification in Adults With and Without Type 1 Diabetes
Authors: Alman Amy C. , Kinney Gregory L. , Tracy Russell P. , Maahs David M. , Hokanson John E. , Rewers Marian J. , Snell-Bergeon Janet K. 
Published: January 2013

OBJECTIVE
The role of inflammation in the increased risk of cardiovascular disease in type 1 diabetes is unclear. We examined the association of inflammation and progression of coronary artery calcification (CAC)—a marker of subclinical atherosclerosis—in adults with and without type 1 diabetes.

RESEARCH DESIGN AND METHODS
A nested case-control study was performed within the prospective cohort of the Coronary Artery Calcification in Type 1 Diabetes (CACTI) study. Participants underwent two CAC measurements ∼2.5 years apart. Case subjects (n = 204) were those with significant progression of CAC. Control subjects (n = 258) were frequency-matched to case subjects on diabetes status, sex, age, and baseline CAC status. Inflammatory marker assessments were performed on stored blood samples from baseline. A principal components analysis (PCA) was performed and a composite score derived from that analysis. The composite score was constructed by assigning a value of 1 for each PCA component where at least one of the markers exceeded the 75th percentile (range 0–4). Conditional logistic regression was used for the matching strategy.

RESULTS
The first two components of the PCA were modestly (odds ratio 1.38 [95% CI 1.08–1.77] and 1.27 [1.02–1.59], respectively) associated with CAC progression after adjustment for other risk factors. The composite score was more strongly associated with CAC progression for those with elevated markers in three or four of the principal components compared with those with none.

CONCLUSIONS
Measures of inflammation were associated with progression of CAC in a population of adults with and without type 1 diabetes.
Visit-to-Visit Blood Pressure Variability Is a Novel Risk Factor for the Development and Progression of Diabetic Nephropathy in Patients With Type 2 Diabetes
Authors: Okada Hiroshi , Fukui Michiaki , Tanaka Muhei , Matsumoto Shinobu , Mineoka Yusuke , Nakanishi Naoko , Asano Mai , Yamazaki Masahiro , Hasegawa Goji , Nakamura Naoto 
Published: January 2013

OBJECTIVE
Recent study has suggested that not only the presence of hypertension but also the variability in systolic blood pressure (SBP) are risk factors for vascular disease and organ damage. The aim of this study was to investigate the relationship between visit-to-visit variability in SBP and change in urinary albumin excretion (UAE) or development of albuminuria in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS
We measured SBP in 354 consecutive patients at every visit during 1 year and calculated the coefficient of variation (CV) of SBP. We performed a follow-up study to assess change in UAE or development of albuminuria, the mean interval of which was 3.76 ± 0.71 years. Then, we evaluated relationships of variability of SBP to diabetic nephropathy using multiple regression analysis and multiple Cox regression model.

RESULTS
Multiple regression analysis demonstrated that CV of SBP was independently associated with change in UAE (β = 0.1758; P = 0.0108). Adjusted Cox regression analyses demonstrated that CV of SBP was associated with an increased hazard of development of albuminuria; hazard ratio was 1.143 (95% CI 1.008–1.302).

CONCLUSIONS
Visit-to-visit variability in SBP could be a novel risk factor for the development and progression of diabetic nephropathy in patients with type 2 diabetes.
Impact of Pre-Therapy Viral Load on Virological Response to Modern First-Line Haart
Authors: Santoro Maria Mercedes , Armenia Daniele , Alteri Claudia , Flandre Philippe , Calcagno Andrea , Santoro Mario , Gori Caterina , Fabeni Lavinia , Bellagamba Rita , Borghi Vanni , Forbici Federica , Latini Alessandra , Palamara Guido , Libertone Raffaella , Tozzi Valerio , Boumis Evangelo , Tommasi Chiara , Pinnetti Carmela , Ammassari Adriana , Nicastri Emanuele , Buonomini Annarita , Svicher Valentina , Andreoni Massimo , Narciso Pasquale , Mussini Cristina , Antinori Andrea , Ceccherini-Silberstein Francesca , Perri Giovanni Di , Perno Carlo Federico 
Published: January 2013

Background We tested whether pre-HAART viraemia affects the achievement and maintenance of virological success in HIV-1-infected patients starting modern first-line therapies. Methods A total of 1,430 patients starting their first HAART (genotype-tailored) in 2008 (median; IQR: 2006–2009) were grouped according to levels of pre-HAART viraemia (≤30,000, 30,001–100,000, 100,001–300,000, 300,001–500,000 and >500,000 copies/ml). The impact of pre-therapy viraemia on the time to virological success (viraemia ≤50 copies/ml) and on the time to virological rebound (first of two consecutive viraemia values >50 copies/ml after virological success) were evaluated by Kaplan–Meier curves and Cox regression analyses. Results Median pre-HAART viraemia was 5.1 log10 copies/ml (IQR 4.5–5.5), and 53% of patients had viraemia >100,000 copies/ml. By week 48, the prevalence of patients reaching virological success was >90% in all pre-HAART viraemia ranges, with the only exception of range >500,000 copies/ml (virological success =83%; P<0.001). Higher pre-HAART viraemia was tightly correlated with longer median time to achieve virological success. Cox multivariable estimates confirmed this result: patients with pre-HAART viraemia >500,000 copies/ml showed the lowest hazard of virological undetectability after adjusting for age, gender, pre-HAART CD4+ T-cell count, transmitted drug resistance, calendar year and third drug administered (adjusted hazard ratio [95% CI]: 0.27 [0.21, 0.35]; P<0.001). Pre-HAART viraemia >500,000 copies/ml was also associated with higher probability of virological rebound compared with patients belonging to lower viraemia strata at weeks 4, 12 and 24 ( P=0.050). Conclusions At the time of modern HAART, and even though an average >90% of virological success, high pre-HAART viraemia remains an independent factor associated with delayed and decreased virological success. Patients starting HAART with >500,000 copies/ml represent a significant population that may deserve special attention.
Correlation of Topometric and Tomographic Indices with Visual Acuity in Patients with Keratoconus
Authors: Ramos Isaac C , Lopes Bernardo T , Faria-Correia Fernando , Valbon Bruno de Freitas , Belin Michael Wellington , Ambrósio Renato 
Published: January 2013

ABSTRACT

Purpose
To evaluate the correlations of Pentacam keratometric, topometric (derived from front surface curvature) and tomographic (derived from 3D corneal shape analysis) indices with best corrected visual acuity in patients with keratoconus.

Materials and methods
One eye randomly selected of 123 patients with bilateral keratoconus was retrospectively enrolled. All patients underwent a comprehensive ophthalmic examination including subjective refraction, distance best-spectacle corrected visual acuity (DCVA) measurement, and rotating Scheimpflug corneal tomography (Pentacam HR; Oculus, Wetzlar, Germany) at the same office visit. The correlations between the logarithm of the minimum angle of resolution (LogMAR) of DCVA and keratometric indices, topometric indices and tomographic indices were tested with nonparametric Spearman correlation coefficients (?).

Results
The mean LogMAR DCVA was 0.32 (~20/42) ±0.27 [range: −0.10 (20/15) to 1.30 (20/400)]. There were strong correlations between DCVA and many keratometric, topometric and tomographic indices. A strong positive correlation was found between DCVA and BAD-Df (ρ = 0.648, p < 0.001), BAD-Db (ρ = 0.633, p < 0.001), K2 (ρ = 0.643, p < 0.001), Kmax (ρ = 0.608, p < 0.001), TKC (ρ = 0.558, p < 0.001), BAD-D (ρ = 0.577, p < 0.001), ISV (ρ = 0.573, p < 0.001), CKI (ρ = 0.530, p < 0.001), KI (ρ = 0.531, p < 0.001). A strong negative correlation was seen between DCVA and Asph Q front 30° (ρ = −0.521, p < 0.001).

Conclusion
There are significant correlations between visual acuity and Pentacam parameters. Such parameters may be considered for improving staging of the disease, as well as for monitoring progression or treatment as outcome measures. There is a potential for combining parameters to enhance the correlations.

How to cite this article
Lopes BT, Ramos IC, Faria-Correia F, Luz A, de Freitas Valbon B, Belin MW, Ambrósio R Jr. Correlation of Topometric and Tomographic Indices with Visual Acuity in Patients with Keratoconus. Int J Kerat Ect Cor Dis 2012;1(3):167-172.
Izquierda uruguaya y culturas obreras. Propuestas al ‘aire libre’: pic-nics y paseos campestres en Montevideo, 1920-1950
Authors: Porrini Rodolfo 
Published: January 2013

El artículo presenta los resultados de una investigación sobre los vínculos entre las ideas y las prácticas de la izquierda uruguaya (anarquista, socialista y comunista) en el uso del tiempo libre por parte de los trabajadores y como esto genera un mundo cultural propio y en tensión con los de las otras clases. Se focaliza en las actividades al “aire libre” en Montevideo (Uruguay) en el tramo 1920-1950. En este trabajo se mostrará especialmente la importancia asignada a “conquistar los espacios” de la ciudad y explorar las bondades del “verde” de la misma, a través de los paseos campestres, pic-nics y excursiones organizados por estas izquierdas.Palabras clave: izquierdas - tiempo libre – picnics - Uruguay AbstractThe paper presents the results of a research work on relations between the ideas and the practices of Uruguayan left (anarchist, socialist and communist) in connection with workmen’s use of leisure time and how that use creates a cultural world of their own and in tension with the one of other social classes. The article focuses on “outdoor” activities in Montevideo between 1920 and 1950, showing especially the emphasis put by the left wing movements in “conquering urban spaces” and explore the goodnesses of the “green” of the same, through the walks campestres, pic-nics and excursions organized by these lefts. Key words: left –leisure time – picnics - Uruguay
“Sendo agora, como se fôssemos, uma família”: laços entre companheiros de viagem no navio negreiro Emília, no Rio de Janeiro e através do Mundo Atlântico
Authors: Hawthorne Walter 
Published: January 2013

Resumo: Este artigo analisa a vida dos africanos num navio negreiro, o Emília. O navio foi capturado pelafragata inglesa Morgiana em 1821 e levado ao Rio de Janeiro. No Rio, a comissão mista anglo-portuguesacondenou o navio pelo crime de comércio ilícito de escravos. Os africanos do Emília ficaram na condição de“africanos livres” sob a custódia do governo local por um período de quatorze anos. Foram distribuídos entreinstituições públicas e concessionários particulares para servir como “trabalhadores livres”. Na prática suasexperiências de trabalho foram semelhantes às de escravos. Depois de quatorze anos, um grupo dos africanoslivres do Emília voltou à África juntos. O artigo propõe que a identidade mais importante para reforçar asrelações entre os africanos não foi uma identidade étnica, mas sim uma identidade nascida no Emília, umaidentidade de companheiros de viagem. Abstract: This article analyzes the lives of a group of Africans from a slave ship, the Emilia. The ship was seizedby the British frigate Morgiana in 1821 and taken to Rio de Janeiro. There, it was condemned by the British andPortuguese mixed commission court for illegal slave trading. The recaptives from the Emilia became “liberatedAfricans” and remained under the custody of the local government for fourteen years. They were distributedamong public institutions and private hirers to serve as “free laborers”. In practice, their labor experiences wereclose to slavery. After fourteen years, a group of the Africans from the Emilia went back to Africa together. Thearticle claims that rather than an ethnic identity, the most important bond among them was the identity theycreated during the middle passage on board the Emília, a shipmate identity.
The Finance-Growth Nexus Revisited: From Origins to a Modern Theoretical Landscape
Authors: Stolbov Mikhail 
Published: January 2013

Abstract
The paper recounts the history of the finance-growth nexus research from its origins to the yearly 1990s. The contributions are analyzed in connection with the socioeconomic context and advances in economic theory. Many ideas first expressed decades ago are still subject to constant discussions and empirical checks, for example, causality direction between finance and economic growth which appeared on the agenda in the mid-1960s. Data improvement and theoretical advances, namely, breakthroughs in the economic theory of information in conjunction with endogenous growth models and growth regressions, shaped the modern landscape of this research program in the early 1990s.