bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent Saiga Population Crash in China Highlights How Conservation of Migratory Species Can Only Succeed with International Collaboration
Authors: Jiang Zhigang , Mallon David , Foggen Marc , Li Chunwang , Cui Shaopeng , Zeng Yan , Ping Xiaoge
Published: February 2020

Saiga (Saiga tatarica) was extirpated in China. Since Mid-1980s, attempts have been made for revival the species in the country, however, only a breeding herd of Saiga was successfully established at Wuwei, Gansu, China. The reintroduced Saiga population experienced a bumpy growth. Then, the population collapsed following the catastrophe die-off in the Saiga ranging countries in Central Asia. After reviewing the population trend and conservation breeding of Saiga in China, we concluded that to establish a migratory species that needs vast range size like Saiga on central Asia steppe, an international collaboration is needed. We recommend China to ratify the CMS in order to facilitate international conservation efforts to restoring the species in its former range.
Rapid Design of a Bait Capture Platform for Culture- and Amplification-Free Next-Generation Sequencing of SARS-CoV-2
Authors: Nasir Jalees A. , Speicher David J. , Kozak Robert A. , Poinar Hendrik N. , Miller Matthew S. , McArthur Andrew G.
Published: February 2020

SARS-CoV-2 is a novel betacoronavirus and the aetiological agent of the current COVID-19 outbreak that originated in Hubei Province, China. While polymerase chain reaction is the front-line tool for SARS-CoV-2 surveillance, application of amplification-free and culture-free methods for isolation of SARS-CoV-2 RNA, partnered with next-generation sequencing, would provide a useful tool for both surveillance and research of SARS-CoV-2. We here release into the public domain a set of bait capture hybridization probe sequences for enrichment of SARS-CoV-2 RNA from complex biological samples. These probe sequences have been designed using rigorous bioinformatics methods to provide sensitivity, accuracy, and minimal off-target hybridization. Probe design was based on existing, validated approaches for detecting antimicrobial resistance genes in complex samples and it is our hope that this SARS-CoV-2 bait capture platform, once validated by those with samples in hand, will be of aid in combating the current outbreak.
RİSK ODAKLI İÇ DENETİMİN STRATEJİK YÖNETİM ANLAYIŞI AÇISINDAN DEĞERLENDİRİLMESİ
Authors: ÇARIKÇI Oğuzhan , YILDIRIM Ahmet
Published: February 2020

Günümüz iş dünyasında işletmeler değişim hızından her zamankinden daha fazla etkilenmektedir. Bir yönetim tekniği ve tercihi olarak değerlendirilen stratejik yönetim anlayışı bu süreçte, işletmeler açısından geleceği kurgulayabilmek için etkili bir şekilde kullanılmaktadır. Stratejik yönetim, işletmelerin yönetsel açıdan olduğu kadar denetim süreçlerinin yapılandırılmasında da etkin rol oynamaktadır. Küreselleşmeyle birlikte artan iş yoğunluğu, işletmelerin geleneksel denetim uygulamalarını yetersiz hale getirmiştir. İşletmeler için riskli faaliyetlerin artması ile birlikte iç denetim uygulamalarından, risk odaklı iç denetim uygulamalarına geçiş gerçekleşmiştir. İşletmelerin gelecekte karşılaşma ihtimali bulunan riskli alanlara yönelmesi, işletmelerin en az kayıpla en fazla kazancı elde etmesi açısından önem taşımaktadır. Söz konusu avantaj ancak, işletmelerin risk barındıran faaliyetleri önceden tespit etmesi ile mümkün olabilecektir. Bu çalışmanın amacı örgütlerde geleceğe yönelik planlanan hedefler ve alınması gereken kararların sağlıklı ve güvenilir bir şekilde gerçekleştirilmesi için risk odaklı iç denetim anlayışına yönelik uygulamamalarından ne düzeyde faydalanılması gerektiğine dair tespitler yapılmasıdır. Bu bağlamda çalışmada nitel araştırma yöntemlerinden doküman incelemesi tekniği kullanılmıştır. Çalışmada iç denetim, risk odaklı denetim, risk yönetimi, stratejik yönetim açısından risk odaklı iç denetim konuları ve ilişkileri incelenmiştir. Çalışma sonucunda özellikle dinamik bir yapı barındıran bazı sektörlerde risk odaklı iç denetim anlayışına dönük bir yönetim kültürünün örgütlere ciddi katkı sağlayabileceği öngörülmektedir.
Microalgas como alternativa sostenible para la producción de biodiesel
Authors: Castellanos Isabel Cristina , González-Peralta Kenia , Pinzón-Torres Santiago Jose
Published: February 2020

Los recientes problemas ambientales asociados a la contaminación atmosférica evocan un especial énfasis investigativo en la búsqueda de fuentes de energía que remplacen los combustibles fósiles, uno de los mayores generadores de contaminación. Desde hace varios años el biodiesel se ha convertido en una alternativa para esta problemática. Este biocombustible se puede producir a partir de diferentes materias primas que minimizan la generación de contaminantes, no obstante, el uso de aceites vegetales o grasas animales como materia prima origina problemáticas asociadas a la deforestación con relación al monocultivo y la promoción de actividades ganaderas.Bajo este panorama, la producción de biodiesel con base en microalgas como fuente de lípidos se ha proyectado como una alternativa sostenible para la industria de biocombustibles. Esta revisión presenta la producción de lípidos a partir de microalgas y plantea nuevos retos dentro de la industria energética, ya que las microalgas se postulan como una fuente de biodiesel renovable que es capaz de satisfacer la demanda mundial de combustibles para el transporte, sin poner en riesgo aspectos sociales ni ambientales. Las microalgas, además de ser la materia prima para el biodiesel, brindan una alternativa en la descontaminación del ambiente, especialmente del aire y del agua. Su producción es económicamente viable, equitativa dentro de la sociedad y ambientalmente soportable; en una palabra, es sostenible.
Verification and Validation of Sensors and Systems Using Systems Engineering Methods
Authors: de Wardt John , Wood Paul
Published: February 2020

The demand for ensuring the reliability and accuracy of drilling sensor data is rapidly increasing with the rise of data analytics and automation. Proven systems engineering methodologies used in the aerospace industry offer the drilling industry a solution for assuring the reliability of sensor data and software processing of this data. This paper describes an approach for verification and validation (V&V) of sensors and systems leveraging experiences from the aerospace industry. Both oil and gas (O&G) and aerospace have high-value assets where failures can lead to significant loss of life and huge financial impacts. Commercial aviation, in particular, has achieved a remarkable improvement in safety over many decades through design standards requiring functions be precisely defined and their implementation be verified against those requirements.

Avaition industry standards, such as DO-178C for Software Considerations in Airborne Systems and Equipment Certification, acknowledge that not all aircraft systems require the same attention. The standards define a range of classification from the most critical, such as autopilots, to the least critical, such as entertainment systems. This paper describes how mapping levels and requirements from DO-178C to oil and gas can assist in the improvement of data quality to the higher standards now required in drilling operations. A range of criticality provides the ability to seek a balance of costs vs. benefits for application to drilling systems to achieve the needed data quality.
An Experimental Study on the Influence of the Chemical Composition of Electrolytes on the SP Curve
Authors: Gondouin M. , Tixier M.P. , Simard G.L.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 210, 1957, pages 58–72.

In the quantitative interpretation of the S.P. logs, the electrochemical component is generally taken equal to -K log Rmf/Rw, where K has the theoretical value corresponding to solutions of pure sodium chloride. This method may be misleading when relatively large quantities of salts other than NaCl are present in formation waters, - as is generally the case for low salinities, - or in gyp-base muds. In such cases recourse is made in the field to changing the K value or to adding a correction term to the equation on the basis of local experience. An investigation has been made in the laboratory of the influence of HCO3, SO4, Ca++ and Mg++ on the amplitude of the S.P. deflection, which included in particular determinations of the activity coefficients of Ca++ and Mg++. The theory, the experimental techniques and a tentative method for applying the results are described. So far, applications to actual field cases where chemical analyses of waters were available have provided an excellent confirmation of the proposed method. The case of the S.P. in very salty brines is also considered and it is shown that the use of activity data for sodium gives satisfactory results.

Historical

In early times of electrical logging, the SP curve was used exclusively as a tool for the location of permeable beds and the definition of their boundaries. Later, with the introduction of methods of quantitative analysis, attention was called to the possibility of deriving from the SP log some information on the formation water resistivity, which constitutes one essential element for the computation of water saturation from log data. The first laboratory experiments in 1932 had shown that, as a result of electrochemical phenomena arising at the contact of the mud and the formation, the amplitude of the deflection of the SP curve was, at least partly, a function of the salt concentration of interstitial water and accordingly of its resistivity. It was indicated that the amplitude of the electrochemical component of the SP should be equal to -K log R1/R2, R1 and R2 being the resistivities of the mud and of the formation water respectively.
A Compositional Material Balance Method for Prediction of Recovery from Volatile Oil Depletion Drive Reservoirs
Authors: Reudelhuber F.O. , Hinds Richard F.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 210, 1957, pages 19–26.

Application of the conventional depletion drive calculation methods to volatile oil reservoirs results in erroneous estimates of ultimate recovery. In view of the increasing number and importance of volatile oil reservoirs, a special technique has been developed which will result in more realistic predictions using laboratory data obtained from reservoir fluid studies of a specific type. The experimental data are designed to permit continuous material accounting and, therefrom, provide the hydrocarbon composition of both the flowing oil and gas phases. The resultant well-stream composition data are then used directly in surface recovery calculations utilizing equilibrium ratios. A step by step procedure, specifically designed for routine use by the practicing reservoir engineer, is presented in an appendix. An actual study performed on a deep Mid-Continent reservoir is used as an illustrative example.

It has been a practice for many years to utilize the conventional material balance methods in conjunction with relative permeability concepts for the prediction of recovery from solution gas drive reservoirs. Those who have performed such calculations recognize that compromises of several types are necessary in order to reduce the calculations to a reasonable degree of complexity. The most serious assumption involved results from the necessity of treating the produced oil and gas as separate fluids, independent of each other in their behavior. It is further assumed that the gas which is evolved in the reservoir as a result of pressure decline will not yield liquid upon the reduction of pressure and temperature resulting from production through surface equipment. Although these shortcomings have been recognized, it has been difficult to attempt refinement of calculation procedures since the laboratory data available normally were not of the proper type or extent to permit such calculations. Three general procedures have been available for depletion drive calculations when laboratory fluid data are of the conventional type.
A Laboratory Investigation of the Effect of Rate on Recovery of Oil by Water Flooding
Authors: Richardson J.G. , Perkins F.M.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 210, 1957, pages 114–121.

Results and procedures are presented covering a laboratory investigation of the effect of rate of water advance on the displacement of oil from clean water-wet sands. The experiments included water floods at atmospheric pressure with and without gas present over a range of flow rates from reservoir rates to rates ten thousand-fold higher. Water floods were also conducted at various rates at elevated pressure with no gas present. Other tests were made at elevated pressures by forming a free gas saturation by evolution of gas from solution in the oil before water flooding. Recovery of oil was found to be independent of the rate of water advance with or without gas present and independent of the pressure level of the water flood.

A dimensionally-scaled model of a reservoir composed of a thick uniform sand was used to study the effect of rate on the tendency of water to underrun the oil because of the greater density of the water. Another model was used to study the effect of rate on the tendency of water to channel down the more permeable sand in a stratified reservoir composed of sands of different permeability in intimate contact. The effect of the presence of gas on the flooding conformance was studied with both models. The results obtained using these simple models provide a basis for predicting behavior in more complicated systems.

Introduction

In spite of the great amount of research on the flow of fluids in porous rocks, there still exists some disagreement as to the influence of the rate of water advance on the displacement of oil by water flooding. Various investigators have found that increasing the rate of water injection would decrease, increase, or have no effect on recovery of oil. One reason for this disagreement has been a lack of understanding of the effects of the capillary forces which influence the results obtained in the laboratory at low rates with short columns. Other causes of the disagreement have undoubtedly been inconstancy and uncertainty of the wetting properties of the porous media studied, inaccurate saturation determinations, and in some instances conclusions based on insufficient data.
The Predicted Performance of a Gas-Condensate System Washington Field, Louisiana
Authors: Berryman James E.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 210, 1957, pages 102–107.

A method is presented for calculating the pressure depletion performance of a gas-condensate reservoir from the original reservoir fluid composition using the laboratory determined pressure-production history and retrograde liquid accumulation as guides. Equilibrium vaporization ratios for this calculation were modified from published data until the calculated dew point pressure and retrograde liquid accumulation agreed with the values observed in the laboratory.

The calculated results are compared with the produced gas composition determined by low temperature analysis during constant volume laboratory experiments of pressure depletion behavior. This comparison shows that the calculation procedure is adequate for determination of gas phase composition.

Data from field separation tests in low temperature separators are presented which verify the applicability of published equilibrium vaporization ratios for a wide range of separator conditions.

Introduction

A reliable prediction of the pressure depletion performance of a gas-condensate reservoir is necessary in determining reserves and evaluating field separation methods. The predicted performance is also used in planning future operations and studying the economics of projects for increasing liquid recovery. Because the flow of fluid in a volumetric gas-condensate reservoir is usually single phase flow, the pressure-depletion performance is primarily a function of the phase behavior of the reservoir fluid.

The properties of a gas-condensate system of major importance are:compressibility factor at reservoir temperature and pressure;dew point pressure;composition changes of the vapor phase with pressure depletion;recovery of original in-place hydrocarbons at any pressure; andretrograde condensate accumulation.

These properties are most generally determined by a pressure depletion-type experiment on recombined separator gas and liquid samples in the laboratory. Ideally the pressure-depletion performance can be calculated from the composition of the original reservoir fluid if the reservoir temperature and initial pressure are known.
Reservoir Volumetric Parameters Defined by Capillary Pressure Studies
Authors: Rockwood S.H. , Lair G.H. , Langford B.J.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 210, 1957, pages 252–259.

Volumetric reservoir analysis is dependent upon a firm relationship between porosity, connate water, and net pay. Capillary pressure data on core samples interrelate these three factors. It is shown that other reservoir problems may be resolved:whether water production is indigenous or extraneous to the oil producing interval,an oil-water contact is being approached, andwhether the oil-water contact is remotely situated.

Introduction

Volumetric analysis of carbonate reservoirs challenges the ingenuity of the reservoir engineer due to an absence of data on the minimum oil-bearing and oil-producing pores of a given reservoir rock. Many studies with this as the ultimate objective are available on the physical characteristics and fluid-flow behaviors of the carbonate reservoir. Some of these publications are: Hassler, Brunner and Deahl's study of the role of capillarity in oil production; Jan Law's and A. C. Bulnes statistical treatment of core analysis data; Chalkley's method for estimating specific surface areas and porosity; Walter Rose's report on porosity, reserves, and recovery; Archie's textural classification of carbonate rocks; Stewart and Spurlock's large core analysis; Purcell's mercury injection method in studying capillary pressure phenomena; Stewart, Craig, and Morse's model multiple-phase flow test in investigating the relative permeability effect; and Fatt's illuminating network model of porous media.

The present study shows that the static reservoir parameters of porosity, connate water, and net productive thickness may be interrelated by utilizing a statistical arrangement of mercury capillary pressure data in addition to routine core analysis. This report summarizes the techniques that are followed to obtain these relations which are applicable to carbonate and sandstone reservoirs that do not contain clays. Capillary pressure statistical studies may be extended to include clay-bearing rocks by utilizing water capillary pressure data.
A Laboratory Study of Solvent Flooding
Authors: Hall H.N. , Geffen T.M.
Published: February 2020

Published in Petroleum Transactions, Volume 210, 1957, pages 48–57.

One-third to one-half of the original oil is left in most reservoirs even after thorough gas drying oar waterflooding. In contrast, essentially all of the oil contacted can be recovered by flooding with a solvent (a fluid miscible with the reservoir oil). It is not economical to fill a reservoir with solvent since the value of the solvent would very likely exceed that of the oil. A practical method would be to inject a small bank of solvent to displace the oil. This solvent bank in turn could be driven through the rock by a less valuable scavenging fluid, such as natural gas which is also miscible with the solvent. Such a method of oil recovery was studied in the laboratory using long (up to 95 feet) core systems.

It was found that, as the solvent moves through the reservoir, the front end of the solvent bank becomes mixed with the oil and forms a relatively short mixing zone between undiluted crude oil and pure solvent. An engineering correlation was obtained which can be used to predict the length of this zone.

Displacement of the solvent by natural gas can be achieved with complete miscibility (above the critical pressure of the gas-solvent system at reservoir temperature) or with partial miscibility at lower pressures. Under conditions of complete miscibility, it was found that length of the gas-solvent mixing zone could be predicted from the correlation developed for the solvent-oil mixing zone. With partial miscibility, two phases exist and the solvent is displaced by a modified gas drive in which vaporization and condensation occur. Equations are developed to predict the performance of this type of displacement.
A Field Test of the Gas-Driven Liquid Propane Method of Oil Recovery
Authors: Jenks Loren H. , Campbell John B. , Binder George G.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 210, 1957, pages 34–39.

Conventional methods of producing crude oil generally leave in the depleted reservoir 1 to 3 bbl of oil for every barrel brought to the surface. This paper describes a field test which explores the possibility of using gas-driven liquid propane to improve oil recovery efficiency.

Laboratory theoretical and experimental studies leading to the field test indicated that low residual oil values could be obtained using limited amounts of propane driven by gas. The field test involvedrepressuring the reservoir to the vapor pressure of liquid propane,injecting the liquid propane, andinjecting dry natural gas to drive the propane and oil to the producing wells.

Considerable preliminary work, including new drilling, work-overs, and a pressure survey was necessary.

During the test, oil production rates have averaged about nine times the final primary rates. The field average GOR is still below the pre-test value. Oil recovery to date is 112,000 STB. About one-third of the 143,000 bbl of propane injected has been produced to date. Results of the C-2 block test are encouraging and larger, more definitive field projects are indicated.

Introduction

The cost of finding new crude oil reservoirs continues to increase. Today the oil industry is drilling more and deeper wells and making fewer big discoveries. Nevertheless, the demand for oil and oil products increases each year. It is natural that oil companies, faced with this situation, concentrate on recovering more of the oil existing in our known crude oil reservoirs. There is room for much improvement. For every barrel of oil brought to the surface by present day methods of producing crude oil, generally 1 to 3 bbl are left behind in the depleted reservoirs.
Miscible Slug Process
Authors: Koch H.A. , Slobod R.L.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 210, 1957, pages 40–47.

This paper discusses a new oil recovery process called the "miscible slug process." This process involves the injection of propane or LPG into the reservoir prior to gas injection. The operating conditions are maintained so that the slug is miscible with both the reservoir oil and the injected gas phase. Thus, a miscible phase displacement is achieved, and high recoveries are obtained from the area of the reservoir contacted.

The most striking discovery of the laboratory study which included displacements from cores up to 125 ft in length was that relatively small slugs of LPQ are effective over reservoir distances in the miscible displacement of oil. This snakes possible the commercial-application of the process.

The important factors controlling the size of the slug are:reservoir length,reservoir fluid composition, andreservoir pressure at the displacement front.

Of lesser importance are the effects of injection rate and porous medium type. Questions which have not been completely answered deal with the effects of gravity and reservoir inhomogeneities on the process.

Introduction

One of the major problems facing the oil industry today is recovery of the large fraction of the discovered oil which will remain unrecovered unless some new processes are found. Water-flooding has been one successful method used to increase recovery over natural depletion. But even successful water floods may leave 25–40 per cent of the pore space filled with residual oil.

Recently a process which involves the use of thermal energy has been reported which may prove useful in increasing recovery from shallow reservoirs containing highly viscous crudes. This paper deals with a new oil recovery process involving use of miscible phases to displace the oil from the reservoir. Miscible phase displacement of oil has been an intriguing idea because the elimination of capillary effects in the reservoir leads to 100 per cent recovery in the areas contacted by the miscible displacing phase. The big deterrent in the past to the practice of miscible phase displacement has been the high cost involved in using large volumes of solvent in the process. The use of high pressure gas to achieve a miscible phase displacement of reservoir oil has been reported as one economically feasible method. However, this process calls for the maintenance of pressures above 3,000 psi at the displacement front.
Rheological Measurements of Non-Newtonian Fluids
Authors: Melton Leonard L. , Saunders Calvin D.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 210, 1957, pages 196–201.

The design and performance of many operations common to the petroleum industry depend upon the unique properties of a class of materials known as non-Newtonian fluids. The art of measuring and describing these properties, called rheology, has fallen far behind the field application of these fluids in this industry. Empirical methods are still employed although theoretically sound methods of analysis are now available.

This paper illustrates a completely general method of analysis of the rheological properties of non-Newtonian fluids which is independent of the type of viscometer employed and also the rheological type of fluid encountered except those of a thixotropic or rheopectic nature.

Values of the rheological properties of a fluid obtained using this method of analysis are based upon an absolute scale of measurement, eliminating the necessity of employing arbitrary concepts of the flow properties of non-Newtonian fluids.

The fundamental nature of this method of analysis is further demonstrated by evaluating the precision with which measurements have been made of these rheological properties by employing a dimensionless criteria - the Fanning friction factor-Reynolds number correlation.

Introduction

Non-Newtonian fluids are not new in the petroleum industry. Particular properties of non-Newtonian materials have been recognized and used to advantage in drilling fluids and have found excellent application in the hydraulic fracturing process.

While usage of these fluids is not new in this industry, the art of measuring and describing their rheological properties is still in its infancy. This is reflected in the accepted method of evaluating drilling fluids, API RP 29, (1950), which recommends a one point "viscosity" measurement. These shortcomings are recognized by various groups in the industry and more adequate methods have been proposed.
Method for Predicting the Back-Pressure Behavior of Low Permeability Natural Gas Wells
Authors: Tek M.R. , Grove M.L. , Poettmann F.H.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 210, 1957, pages 302–309.

The general problem of single-phase natural gas flow through porous media has been considered both by mathematical analysis and field experiments. Theoretical studies on the fluid dynamics of natural gas wells resulted in derivations of expressions which permit a better understanding of the flow mechanism for conditions under which Darcy's law is no longer valid.

In applying these results to natural gas production and testing technology, special emphasis was placed on the study of low permeability, slowly stabilizing formations. These applications resulted in a method of predicting the performance coefficients of tight natural gas wells.

The calculation of the performance coefficient requires the determination of the "test-index", the drainage radius, and the effective wellbore radius.

Methods for estimating these parameters from field data were also developed.

Field data from 15 wells were collected and analyzed. The measured values of the performance coefficients were compared with the predicted values. This statistical evaluation gave a bias of 7.14 per cent and a standard deviation of 11.6 per cent.

Introduction

The performance of a natural gas well is determined by the physical properties of the reservoir rock, the extent and the geometry of the drainage area, the properties of the flowing fluid, and the conditions of pressure distribution within the drainage matrix.

The relation between the quantity of gas delivered and the pressure drop within the reservoir is characteristic of the behavior of each well and is often referred to as the back-pressure behavior of the well.

Important engineering and production problems such as calculation of gas deliverability into a pipeline at a predetermined line pressure, design and analysis of gas-gathering lines, determinations of spacing and number of wells to be drilled during field development to meet future market or contract obligations, etc., all depend, at least in part, on the availability and use of reliable back-pressure curves.
An Evaluation of the Procedures Used in the Determination of the Grain Densities of Petroleum Reservoir Minerals
Authors: Brooks C.S.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 210, 1957, pages 235–244.

Several of the commonly used methods for determination of effective grain densities of minerals have been evaluated for accuracy and precision, and their applicability to various types of petroleum reservoir minerals tested. Consideration was given to the effect of consolidation, swelling clay, and wettability on these grain-density determinations.

Procedures with helium displacement, a modified low-pressure Boyle's law porosimeter, and liquid displacement (water, n-decane, and n-octanol) were tested. The helium-displacement procedure was used primarily as an independent reference for which the effects of fluid-solid interaction, e.g., adsorption and wettability, were negligible. The procedures with the Boyle's law porosimeter and with liquid displacement are the methods in common use.

Minerals investigated included calcite, West Texas limestone core samples, California sandstone core samples, and Wyoming bentonite. The number of samples tested, while not large, was adequate to permit application of statistical methods.

Grain-density measurements on calcite (Iceland spar) provided a basis of comparison for the accuracy and precision of the procedures under investigation for a material with a high degree of chemical and physical homogeneity and for which fluid-solid interactions were at a minimum.

Liquid-displacement procedures (water or n-decane) provided the greatest reliability and precision for measurement of the grain densities of the limestone tested.

Gas-displacement procedures (helium or Boyle's law porosimeter) provided the greatest reliability and experimental convenience, if not the greatest precision, for the measurement of the grain densities of the swelling clay, Wyoming bentonite, and the shaly sandstones which contained appreciable amounts of swelling, interstitial clays.

These experiments were designed to evaluate the applicability of the grain-density procedures in common use to some of the less tractable minerals-tight limestones, shaly sandstones, and swelling clays. The results should provide a useful basis for a selection of the method most suitable for application to the various petroleum reservoir minerals encountered and especially for use in the estimation of formation porosity.
Log Interpretation in Heterogeneous Carbonate Reservoirs
Authors: Winn R.H.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 210, 1957, pages 268–274.

Introduction

In this paper a heterogeneous carbonate reservoir is considered as a succession of layers of formations of radically different porosities, permeabilities, water saturations, and rock matrix types; i.e., the heterogeneity is vertical rather than radial to the wellbore. Presumably each layer is more or less homogeneous.

To determine the "et oil in place" in this reservoir it is desirable to know the porosity and water saturation of each layer. In addition, the section must be subdivided into that which will produce oil, that which will produce water, and that which will produce little or nothing.

In numerous wells drilled in these reservoirs radioactivity surveys, guard electrode surveys, and caliper surveys have been made. These logs have been compared with core analysis data, when available, and the analysis of the surveys compared with production data. This study, still in progress, is intended to provide improved analytical techniques if such are possible. This paper is a progress report on the work.

Determination of Porosity

The neutron-gamma log has long been recognized as a measure of hydrogen concentration. In reservoirs that are free of clay, shale, or other hydrogen containing matrices, it has been accepted as a measure of porosity. Empirical methods to relate relative neutron-gamma intensity to porosity are often employed.

To provide a more precise determination of porosity from the neutron-gamma log each instrument is calibrated immediately prior to each survey by a method which refers all tools to a hydrogenous cylinder. To insure stability a calibration check is made after each survey. These calibration records are printed as an integral part of the log that is recorded in standard counts per second. A detailed description of the calibration procedure is available in the literature. The procedure employed insures that each survey is numerically reproducible within the limits of statistical variation.

To relate the standard neutron counts per second to porosity and hole size, records were made in test wells constructed of blocks of limestone.
Density Logging with Gamma Rays
Authors: Baker P.E.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 210, 1957, pages 289–294.

An improved method of logging formation density has been developed in which the formation is bombarded with a collimated beam of gamma rays. By means of a scintillation detector and pulse height discriminator, the gamma-ray energy band is accepted and recorded which corresponds to deepest penetration into the formation. Laboratory tests on a field tool revealed no borehole diameter effect for smooth holes and no effect of formation chemistry, except insofar as chemistry affects density. In extensive field tests, the density log has exhibited satisfactory agreement with core measurements and has correlated accurately with other logs.

Introduction

This paper describes an improved method of logging formation density by means of back-scattered gamma rays to penetrate the formation together with energy discrimination to select only that energy (or frequency) range corresponding to deepest penetration into the formation. This method of density logging was developed at the La Habra laboratory of California Research Corp.

Field instruments have been built and tested by McCullough Tool Co. and commercial service has begun in some areas. All of the data discussed here were obtained for the original field tool.

The density log can be a valuable adjunct to existing logs because of its use in determining porosity quantitatively. It is useful also in connection with seismic and gravity surveys where formation density information is of interest.
Identification of NHXs in Gossypium species and the positive role of GhNHX1 in salt tolerance
Authors: Long Lu , Zhao Jing-Ruo , Guo Dan-dan , Ma Xiao-Nan , Xu Fu-Chun , Yang Wen-Wen , Gao Wei
Published: February 2020

Background: Plant Na+/H+ antiporters (NHXs) are membrane-localized proteins that maintain cellular Na+/K+ and pH homeostasis. Considerable evidence highlighted the critical roles of NHX family in plant development and salt response; however, NHXs in cotton are rarely studied.Results: The comprehensive and systematic comparative study of NHXs in three Gossypium species was performed. We identified 12, 12, and 23 putative NHX proteins from G. arboreum, G. raimondii, and G. hirsutum, respectively. Phylogenetic study revealed that repeated polyploidization of Gossypium spp. contributed to the expansion of NHX family. Gene structure analysis showed that cotton NHXs contain many introns, which will lead to alternative splicing and help plants to adapt to high salt concentrations in soil. The expression changes of NHXs indicate the possible differences in the roles of distinct NHXs in salt response. GhNHX1 was proved to be located in the vacuolar system and intensively induced by salt stress in cotton. Silencing of GhNHX1 resulted in enhanced sensitivity of cotton seedlings to high salt concentrations, which suggests that GhNHX1 positively regulates cotton tolerance to salt stress.Conclusion: We characterized the gene structure, phylogenetic relationship, chromosomal location, and expression pattern of NHX genes from G. arboreum, G. raimondii, and G. hirsutum. Our findings indicated that the cotton NHX genes are regulated meticulously and differently at the transcription level with possible alternative splicing. The tolerance of plants to salt stress may rely on the expression level of a particular NHX, rather than the number of NHXs in the genome. This study could provide significant insights into the function of plant NHXs, as well as propose promising candidate genes for breeding salt-resistant cotton cultivars.
Vector analysis of Contoura Vision for the correction of myopia and myopic astigmatism
Authors: Lin Ying , Su Huanjun , Wu Jianbin , Zhang Xia , Yuan Muzhi
Published: February 2020

Objective: To evaluate the visual outcomes of Contoura Vision with automatic eye tracking system in eyes with myopia and myopic astigmatism. Methods: In this prospective study, 40 consecutive patients (80 eyes) with moderate myopia and irregular astigmatism were included from January to August 2018 at Liuzhou Worker’s Hospital. Subjects were randomly divided into an experimental group (40 eyes) that underwent Contoura Vision FS-LASIK and a control group (40 eyes) that underwent wavefront-optimized FS-LASIK. Target refractions of all subjects were plano. Visual outcomes and astigmatic vector analysis were evaluated and compared between preoperatively and 3 months post-operatively. Results: The preoperative spherical and cylindrical refractive errors were similar in both groups (P>0.05). At 3 months postoperatively, cumulative uncorrected distance visual acuity (UDVA) was 20/16, 20/20, or 20/25 in 30 %, 95%, 100 % of patients in the experimental group, respectively. The experimental group was better than the control group in predictability of astigmatism correction at 3 months after operation. In the experimental group, 80% of eyes had deviation of astigmatic axis within 15° and 35% of eyes had deviation of astigmatic axis within 5°, both were better than those in the control group. The number of eyes with residual astigmatism within 0.5D were higher in the experimental group (60%, 24 eyes) than the control group (50%, 20 eyes). Compared with the preoperative, C7 significantly reduced to 0.056±0.030 in the experimental group at 3 months after the procedure (P<0.05), and were significantly lower than those in the control group (P<0.05). Conclusion: Contoura Vision with automatic eye tracking system was safe and effective for the correction of myopia and myopic astigmatism.
Service user and family participation in mental health policy making in Timor-Leste: a qualitative study with multiple stakeholders
Authors: Hall Teresa , Kakuma Ritsuko , Palmer Lisa , Minas Harry , Martins João , Armstrong Greg
Published: February 2020

Introduction Participation in mental health system strengthening by people with mental health problems and their families is a cornerstone of people-centred mental health care, yet there is a dearth of research about participation from low- and middle-income countries (LMICs), particularly from the Asia Pacific region. Hence, this study aimed to assess the current situation, challenges, enabling factors and future actions for service user and family participation in mental health policy making in Timor-Leste. Methods In-depth interviews were conducted with 85 adults (≥18 years) who were: (1) mental health service users (n = 20) and their families (n = 10); (2) government decision makers (n = 10); (3) mental health and social service providers (n = 23); (4) civil society (n = 9); and (5) other groups (n = 13). Interview data was analysed using framework analysis. Results There was limited service user, family and community participation in mental health policy making in Timor-Leste. Perceptions that policy making is a technical exercise and that people with mental health problems lack cognitive capacity, and a lack of supportive mechanisms challenged participation. Enabling factors were a strong focus on human rights within the social sector, and existing mechanisms for advocacy and representation of people with disabilities in social policy making. Participants suggested bolstering civil society representation of people with mental health problems, and increasing mental health awareness and literacy, including government competencies to facilitate service user participation. Conclusion The findings highlight the need for theoretical and practical focus on the role of family within mental health system development in LMICs. Global mental health research and practice should adopt a critical approach to mental health service user and family participation to ensure that the concept and strategies to achieve this are embedded in LMIC knowledge.
Transcriptomic analysis of bovine monocytes in response to non-cytopathic bovine viral diarrhea virus infection
Authors: HE Yanhua , HE Jinke , YANG Yajun , HUANG Xin , ZHANG Yunfen , XIAO Chencheng , ZHAO Xinxia , MA Xusheng , GUO Tao , ZHONG Fagang , CHEN Chuangfu
Published: February 2020

Background: Monocytes are significant players in the detection of invading pathogens, particularly in pathogen defense. Bovine Viral Diarrhea Virus (BVDV) can cause a persistent infection and immune suppression if animals are infected with an non-cytopathic (ncp) biotype. However, its exact role in ncp BVDV1-infected bovine monocytes remains poorly understood. Results: RNA sequencing (RNA-seq) was used to investigate the effect of ncp BVDV1 infection on the transcriptional profile of bovine monocytes. Compared with the non-infected cells, 9959 and 7977 differentially expressed gene (DEGs) were identified at 2 and 24 h hpi, respectively. These DEGs were associated with signal transduction, immune response, apoptotic process, cellular process , binding and cellular component. The differential expression profiles of select the type I interferon signaling pathway , interferon (IFN)-stimulated genes (ISGs), and genes involved in the innate immune response, including IRF7, DDX3X, TLR13, DDX58(RIG-I), MVAS, TLR9, TRAF6, IRF1, IFIT1, STAT1, ISG20, TRIM25, MX1,NLRX1, CYLD, SIKE1 and ZAP70 were confirmed by real-time quantitative PCR and consistent with the RNA-seq data. Conclusion: Our transciptome anslysis provides useful initial data towards better understanding of the infection mechanisms used by ncp BVDV1, while highlighting the potential molecular relationships occurring between the virus and the host’s immune response.
Nitric oxide is involved in the brassinolide-induced adventitious root development in cucumber
Authors: Yutong Li , Wu Yue , Liao Weibiao , Hu Linli , Dawuda Mohammed Mujitaba , Jin Xin , Tang Zhongqi , Yang Jianjun , Yu Jihua
Published: February 2020

Background: Brassinolide (BR), as a new type of plant hormones, is involved in the processes of plant growth and stress response. Previous studies have reported the roles of BR in regulating plant developmental processes and also response tolerance to abiotic stresses in plants. The main purpose of our study was to explore whether nitric oxide (NO) plays a role in the process of BR-induced adventitious root formation in cucumber (Cucumis sativus L.). Results: Exogenous application of 1 μM BR significantly promoted adventitious rooting, while high concentrations of BR (2-8 μM) effectively inhibited adventitious rooting. NO donor (S-nitroso-N-acerylpenicillamine, SNAP) promoted the occurrence of adventitious roots. Simultaneously, BR and SNAP applied together significantly promoted adventitious rooting and the combined effect was superior to the application of BR or SNAP alone. Moreover, NO scavenger (c-PTIO) and inhibitors (L-NAME and Tungstate) inhibited the positive effects of BR on adventitious rooting. BR at 1 μM also increased endogenous NO content, NO synthase (NOS-like) and Nitrate reductase (NR) activities, while BRz (a specific BR biosynthesis inhibitor) decreased these effects. In addition, the relative expression level of NR was up-regulated by BR and SNAP, whereas BRz down-regulated it. The application of NO inhibitor (Tungstate) in BR also inhibited the up-regulation of NR. Conclusion: BR promoted the formation of adventitious roots by inducing the production of endogenous NO in cucumber.
HIV-exposed infant follow-up in Mozambique: Formative research findings for the design of a cluster randomized controlled trial to improve testing and ART initiation
Authors: Vieira Lúcia C , Mahumane Arlete Miloque , Napua Manuel , Chale Falume Azamo , Manuel João Luís , Cowan Jessica Greenberg , Sherr Kenneth , Chapman Rachel R , Pfeiffer James T
Published: February 2020

Background: Early infant diagnosis (EID) of HIV-exposed and initiation of HIV-positive infants on anti-retroviral therapy (ART) requires a well-coordinated cascade of care. Loss-to-follow-up (LTFU) can occur at multiple steps and effective EID is impeded by human resource constraints, difficulty with patient tracking, and long waiting periods. The objective of this research was to conduct formative research to guide the development of an intervention to improve the pediatric HIV care cascade in central Mozambique. The study was conducted in Manica and Sofala Provinces where the adult HIV burden is higher than the national average. The research focused on 3 large clinics in each province, along the highly populated Beira corridor. Methods: The research was conducted in 2014 over 3 months at six facilities and consisted of 1) patient flow mapping and collection of health systems data from postpartum, child-at-risk, and ART service registries, 2) measurement of clinic waiting times, and 3) patient and health worker focus groups. Results: HIV testing and ART initiation coverage for mothers tends to be high, but EID and pediatric ART initiation are hampered by lack of patient tracking, long waiting times, and inadequate counseling to navigate the care cascade. About 76% of HIV-positive infants were LTFU and did not initiate ART. Conclusions: Effective interventions to reduce LTFU in EID and improve pediatric ART initiation should focus on patient tracking, active follow-up of defaulting patients, reduction in EID turn-around times for PCR results, and initiation of ART by nurses in child-at-risk services. TRIAL REGISTRATION: Retrospectively registered, ISRCTN67747315, July 24, 2019.