bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution of candidate transcriptional regulatory motifs since the human-chimpanzee divergence
Authors: Donaldson Ian J , Göttgens Berthold 
Published: July 2012

Abstract
Background
Despite the recent completion of the chimpanzee genome project, few functionally significant sequence differences between humans and chimpanzees have thus far been identified. Alteration in transcriptional regulatory mechanisms represents an important platform for evolutionary change, suggesting that a significant proportion of functional human-chimpanzee sequence differences may affect regulatory elements.

Results
To explore this hypothesis, we performed genome-wide identification of conserved candidate transcription-factor binding sites that have evolved since the divergence of humans and chimpanzees. Analysis of candidate transcription-factor binding sites conserved between mouse and chimpanzee yet absent in human indicated that loss of candidate transcription-factor binding sites in the human lineage was not random but instead correlated with the biologic functions of associated genes.

Conclusion
Our data support the notion that changes in transcriptional regulation have contributed to the recent evolution of humans. Moreover, genes associated with mutated candidate transcription-factor binding sites highlight potential pathways underlying human-chimpanzee divergence.
Digital soil mapping of compositional particle-size fractions using proximal and remotely sensed ancillary data
Authors: Buchanan S. , Triantafilis J. , Odeh I. O. A. , Subansinghe R. 
Published: July 2012

The soil particle-size fractions (PSFs) are one of the most important attributes to influence soil physical (e.g., soil hydraulic properties) and chemical (e.g., cation exchange) processes. There is an increasing need, therefore, for high-resolution digital prediction of PSFs to improve our ability to manage agricultural land. Consequently, use of ancillary data to make cheaper high-resolution predictions of soil properties is becoming popular. This approach is known as “digital soil mapping.” However, most commonly employed techniques (e.g., multiple linear regression or MLR) do not consider the special requirements of a regionalized composition, namely PSF; (1) should be nonnegative (2) should sum to a constant at each location, and (3) estimation should be constrained to produce an unbiased estimation, to avoid false interpretation. Previous studies have shown that the use of the additive log-ratio transformation (ALR) is an appropriate technique to meet the requirements of a composition. In this study, we investigated the use of ancillary data (i.e., electromagnetic (EM), gamma-ray spectrometry, Landsat TM, and a digital elevation model to predict soil PSF using MLR and generalized additive models (GAM) in a standard form and with an ALR transformation applied to the optimal method (GAM-ALR). The results show that the use of ancillary data improved prediction precision by around 30% for clay, 30% for sand, and 7% for silt for all techniques (MLR, GAM, and GAM-ALR) when compared to ordinary kriging. However, the ALR technique had the advantage of adhering to the special requirements of a composition, with all predicted values nonnegative and PSFs summing to unity at each prediction point and giving more accurate textural prediction.
Cartographical Quandaries: the Limits of Knowledge Production in Burton's and Speke's Search for the Source of the Nile
Authors: Wisnicki Adrian S. 
Published: July 2012

When he sighted the southern end of Lake Victoria on 3 August 1858, John Hanning Speke (1859b:397) realized that he had discovered the “source” of the White Nile, the most important tributary of the Nile proper, and so had “almost, if not entirely, solved a problem which it has been the first geographical desideratum of many thousand years to ascertain, and the ambition of the first monarchs of the world to unravel.” That Speke was an unknown explorer and that he had made his discovery on a solo “flying trip” during the East African Expedition of 1856-59, which, under the command of the renowned explorer Richard Francis Burton, had already also discovered Lake Tanganyika, made Speke's accomplishment all the more remarkable.As contemporaries soon asserted, Speke's discovery culminated a historical series of excursions, real and imagined, into the interior of Africa and placed Speke at the pinnacle of a line of explorers and geographers that ran from Herodotus, Julius Caesar, and Ptolemy to, in more recent times, James Bruce (the Scotsman who “discovered” the source of the Blue Nile, the second most important tributary of the Nile, in 1770), the German missionaries Ludwig Krapf and Johannes Rebmann (who “discovered,” respectively, the snow-capped mountains of Kilimanjaro in 1848 and Kenya in 1849), and noted “armchair geographers” like W.D. Cooley, Charles Beke, and James M'Queen.
Spoken Reminiscences of Political Agents in Northern Nigeria II
Authors: Afeadie Philip Atsu 
Published: July 2012

Q. Sir, I would like to know something about messengers and interpreters like Adamu Jakada.A. Adamu Jakada was the messenger between Emir Abbas and the Europeans. Some of the messengers and interpreters were employed by the emir, and they were royal slaves. Whenever they did something wrong they were replaced by others. Adamu was a slave of the emir.Q. Where and when was he born?A. He was born in Kano, and he came from the family of slaves.Q. Is there any story about him?A. All we know is that he was chosen by the District Officer (D.O.) He would take messages from the emir to the white men and return with the white man's reply to the emir.Q. Were messengers and interpreters powerful?A. Yes, indeed.Q. Were they nice people?A. It is when they became powerful that issues of misunderstanding occurred. You know when somebody becomes powerful the person would demonstrate good and bad qualities. Some of the messengers and interpreters were like that.Q. Were they wealthy?A. They were slaves of the emir. Everything that they owned, they took them from the servants of the emir. Also, they were paid by government.Q. What did people think of their work?A. People respected and feared them because of their closeness to the emir and the Europeans.Q. Did they speak or write in English?A. Before they learnt English they used to work as servants to the Europeans. So they learned English from them.
Examining Text Sediments–Commending a Pioneer Historian as an “African Herodotus”: On the Making of the New Annotated Edition of C.C. Reindorf'sHistory of the Gold Coast and Asante
Authors: Hauser-Renner Heinz 
Published: July 2012

In 1995 Paul Jenkins, the former Basel Mission archivist, called my attention to Carl Christian Reindorf's Ga manuscripts kept at the archives in Basel, knowing that I had lived and worked in Ghana in the 1980s and that I was able to speak, read, and write the Gã language of Accra and its neigborhood. Of course I already knew Reindorf and his monumentalHistory of the Gold Coast and Asantepublished in 1895 in English, as I had written my M.A. thesis on late-nineteenth-century Asante history, and moreover I was very much interested in Gã history. Reindorf's massive, substantive, and systematic work about the people of modern southern Ghana may be considered a pioneering intellectual achievement because it was one of the first large-scale historical work about an African region written by an African, and it was highly innovative, including both written sources and oral historical narratives and new methods for the reconstruction of African history. The book has excited interest ever since it first appeared 110 years ago because it contains an unrivaled wealth of information on the history and culture of southern Ghana.A preliminary glimpse at the two heaps of folios wrapped with linen ropes at the archives showed that the manuscripts-none of them were dated–contained two different versions of the EnglishHistory. That day, when I first laid my hands on the brownish, carefully folded papers, I was not aware that I was to embark on an intensive period of arduous transcribing and translating work (sometimes “lost in translation”), breathtaking archival investigations in Basel, London, and Accra, and of an exciting text/context research (unearthing sources, excavating informants, examining sediments/versions).
The Historiography of HIV and AIDS in Uganda
Authors: Kuhanen Jan 
Published: July 2012

Uganda has been in the world headlines since the mid-1980s, first as a nation severely hit by HIV and AIDS, and later, from the late 1990s onwards, as the first country in sub-Saharan Africa that has managed to reverse a generalised HIV epidemic. Countless newspaper articles, television and radio documentaries and broadcasts, papers, books, and films have been produced about AIDS in Uganda, making the epidemic one of the most thoroughly researched and documented in the world. Medical doctors, virologists, epidemiologists and social and behavioral scientists, both Ugandan and expatriate, have produced massive amounts of scientific information about it since the early 1980s, in addition to which there have been policy papers, evaluation reports, and action plans produced by various government ministries, international donor agencies, and national and international NGOs and relief organizations which document the epidemic from administrative, developmental, and humanitarian perspectives.Uganda's AIDS epidemic has been publicized worldwide through the news media and various international agencies. It is being constantly monitored not only by national authorities and international health experts, but by myriads of Ugandan and international organizations, media, academics, and concerned members of the public using modern means of communication. Some of these national and international bodies not only monitor, report and educate, but demand their say in how the epidemic should be managed. Uganda has become a testing ground for medical and behavioral interventions, as exemplified by AIDS vaccination trials, the social marketing of condoms, antiretroviral treatment, and, recently, by the male circumcision trial. Positive results have then been marketed to other countries in sub-Saharan Africa as successful AIDS prevention strategies.
Mombasa Cathedral and the CMS Compound: the Years of the East Africa Protectorate
Authors: Frankl P. J. L. 
Published: July 2012

Exactly when Islam arrived on the Swahili coast is difficult to say, but Mombasa was a Muslim town long before the arrival of Vasco da Gama in 1498. During the two centuries or so that the Portuguese-Christians occupied this part of the sea route from Europe to India there were churches in Mombasa and elsewhere in Swahililand, but none has endured. Modern Christianity dates from 1844, when Ludwig Krapf arrived in Mombasa. Before then Mombasa was a “wholly Mohammedan” town. Krapf, a German Lutheran, was employed by the Church Missionary Society (CMS) based in London. Failing to make any converts on the island, Krapf moved into the coastal hinterland, among the Nyika, where Islam was less in evidence and where, therefore, Krapf was more hopeful of success. With remarkable perspicacity he wrote: “Christianity and civilisation ever go hand in hand…. A black bishop and black clergy of the Protestant Church may, ere long, become a necessity in the civilisation of Africa.”In England, when attention was drawn to the east African slave trade, a settlement of liberated slaves was established on the mainland north of Mombasa island in 1875, and a church built (Emmanuel Church, Frere Town)—the first parcel of land in central Swahililand to be owned by European-Christians. There was still no church on the island. However, this was the zenith of the British imperial power and in the capital of almost every major British overseas possession, it was de rigueur—alongside the Secretariat and the Club—to have a Church of England cathedral.
Biodiesel-based Drilling Fluids
Authors: Wang Meishan , Sun Mingbo , Shang Hongyan , Fan Songlin , Liu Meiquan , Liu Fupeng 
Published: July 2012

Abstract
The rheological properties of biodiese and white oil were compared at normal temperature and high temperature in this paper. The ability of biodiesel to inhibit shale expansion was investigated. The results showed that the rheological properties of biodiese were better than white oil. Biodiese also showed better resistance to high temperature and shale expansion. Organo- lignite and vegetable pitch were used to reduce the filtration in biodiesel-based drilling fluids system. The optimum formulation of biodiesel-based drilling fluids was determined by experiments. In order to simulate the contamination of calcium and dry soil, CaSO4·2H2O and sodium-based bentonite were added to the system, and the experimental results showed that the tolerance of biodiesel-based drilling fluids to the contamination of calcium and dry soil is desirable.
Applications of New Coiled Tubing Multi-staged Fracturing Technology
Authors: Xiude Lu , Dengsheng Ye , Juhui Zhu , Dan Song , Congbin Yin , Guan Bin , Wang Guigang 
Published: July 2012

Abstract
Multiple new technologies of stimulations have been successfully developed and used in domestic low permeability reservoirs over the last few years. A new staged fracturing technique with bottom annular packer on coiled tubing (CT) has been extensively used in the fields of Sichuan. This process employs a new bottomhole tool assembly (BHA) on the CT, which offers the opportunity to achieve hydro-jet perforating, annular packing and fracturing multiple pay zones with a single entry of the CT string. This technique has proven effective in stimulating thin interbedded reservoirs individually to open pay zones and improve gas production optimally. Following the final CT stimulating stage, the well is cleaned out and for subsequent production. This paper describes the unique features of the coiled tubing staged fracturing technology with bottom annular packer. Case studies of seven well are presented on this paper. The key procedure controls and surface process enhancements during the applications of the new CT stimulation technique will also be analyzed and summarized.
Study on Reaming Technology of Sidetrack Drilling Horizontal Well at Liaohe Oilfield
Authors: Ding Wenzheng , Peng Gang , Cao Sheng , Wu Sheng , Zhang Shijun , Luo Da , Li Zhuang 
Published: July 2012

Abstract
Liaohe oilfield has come to its late-mid exploitation period after 40 years’ exploration and development, tapping potentialities for more benefits and enhancing oil recovery have been emphasized in oilfield exploration. Sidetrack horizontal well technology has advantages of sidetrack well and horizontal well, and now it has become an important technique for oilfield to tap potentialities for more benefits. The development of sidetrack horizontal well technology has been restricted because of small annulus, complex well track, difficulties of tripping in casing pipe and bad cementing quality, in order to solve these problem, reaming technology has been used to enlarge open well diameter of sidetrack horizontal well by gWdC.
So far, GWDC has finished reaming process for about 800 wells, including 15 wells of sidetrack horizontal well. Open well diameter was enlarged after reaming, thus tail pipe can be tripped in smoothly without block, the strength of cement sheath and cement quality improved, oil well life prolonged and drilling cost saved obviously.
Reaming technology has facilitated sidetrack horizontal well technology to large-scale application, and provided forceful technical guarantee for dependable crop and synergy of oilfields.
Practicing and Learning of Shale Gas Staged Fracturing in Sichuan Basin – A Case for the W1 Horizontal Well
Authors: FU Yongqiang , XIAO Yongjun , CHEN Yuanlin , ZENG Lixin 
Published: July 2012

Abstract
Weiyuan&Changning marine shale reservoirs in Sichuan Basin have been included in the first national shale development industries demonstration area. This paper based on the premise of the pre-vertical well fracturing reconstruction of the demonstration area, learning the experience of the similar shale reservoir horizontal staged fracturing in the North American, and combining with the characteristic of shale formation in the demonstration area, we carried out the analysis of rock mechanics and developed the optimization and evaluation of the fracturing fluid system, and completed the staged fracturing design of the first shale horizontal W1 well, then successful carried into execution in situ. By the evaluation of staged fracturing technology and the analysis of the effect after fracturing, we summed up the adaptability of the North American shale staged fracturing technology used in the demonstration area, and some problems have been shown up in the horizontal staged fracturing in the Weiyuan shale reservoir of Sichuan Basin due to its own characteristics. This paper provides an overview of the completion and stimulation of the first shale horizontal well, describes the lessons learned along the way, and discusses the implications for the future Weiyuan shale gas horizontal well development.
Self-Oscillation Pulsed Percussive Rotary Tool Enhances Drilling Through Hard Igneous Formations
Authors: Cheng Rongchao , Ge Yunhua , Wang Haige , Ni Hongjian , Zhang Hongjun , Sun Qingren 
Published: July 2012

Abstract
As hydrocarbon development goes deeper and more complex in Songliao Basin, drilling engineering has been put at the forefront of cost reduction and efficiency enhancement. The unique challenges resulted from high abrasiveness in hard igneous formations have triggered years of efforts for cost-effective percussive rotary drilling technology. This paper will highlight the development and application of a self-oscillation pulsed percussive tool, with in-depth analysis of its active mechanism and numerical modeling results of pressure and velocity distribution inside the self-oscillation chamber.
A two-stage oscillator designed on acoustic philosophy is introduced in the tool to create hydraulic pulse after resonance, feedback, frequency selection and amplification of high speed flow downhole. The pulse immediately induces the periodic impact against bit with high frequency and low amplitude using an appropriate hydraulic energy transfer structure. The pulsed jet, mechanical percussion and rotation are integrated to enhance breaking of hard rocks. The vibration frequency, peak value and amplitude can be adjusted with respect to oscillator geometry, size of drive spindle, and the distance between oscillator outlet and spindle top.
The elimination of moving part like conventional percussion hammer significantly simplifies tool structure, allowing better assurance of security and reliability in harsh environment. Primary test in South Songliao and extended application in Sichuan and Tarim Basin demonstrate that the tool can deliver improved ROP by 20%-36% compared with offset wells, prolonged percussion durability of more than 150 hours, enhanced deviation control capability, favorable erosion resistance and HT resistance rated to 200. Meanwhile, the pulsed jet through bit nozzles helps to improve hole cleaning and decrease rock's fracture strength.
The tool and related operational procedure provides a new enabler to conquer drilling challenges in igneous rocks, as well as in tight shale, sandstone and huge-layer of gravel encountered in China.
LWD Azimuthal Laterolog Resistivity Logging in Unconventional Reservoirs
Authors: Sinclair Paul , Anzong Li , Otteman Aaron , Wennekamp Alisha 
Published: July 2012

Abstract
The development of unconventional oil and gas resources is critically dependent on accurate geosteering of horizontal wells. A new type of LWD Azimuthal Laterolog Resistivity logging tool has been introduced that is specifically designed for geosteering and formation evaluation in complex carbonates, shale-gas, shale-oil, and coal-bed methane formations.
The new tool is able to detect approach to a distant parallel bed-boundary of contrasting resistivity that is either higher or lower than the borehole environment. This enables predictive geosteering if the tool is not installed too far from the drill-bit. Conventional wave-propagation tools respond mainly to nearby conductive anomalies, which can limit their application in geosteering shale-oil wells where the target formation is often lower resistivity than those on upper or lower boundaries, or when the borehole traverses a fault and the target formation is higher resistivity and located in an unknown direction.
Laterolog types of tools are capable of accurate measurement over a wide range of resistivity from 0.2 – 20,000 ohm.meters, enabling hydrocarbon saturation calculation even in tight carbonate formations. Many carbonate formations, and most coal seams, produce from natural fractures or vugs. The new tool has thin-bed resolution of 0.14 meters, enabling it to image the more productive zones for real-time production analysis while drilling, with significant potential cost-savings.
The GRT tool has been commercial for two years, accumulating several thousands of hours of drilling time in operations provided by several independent MWD service companies. Successful geosteering jobs have been completed in the Montney, Bakken, Viking (Canada), Niobrara, and Avalon (USA) unconventional formations. The first test in China was in Talimu Oilfield, where the new tool was able to reproduce logs from a wireline Dual Laterolog in resistivities ranging from 20,000 – 100,000 ohm.meters. Tests have also been run in Tuha and Changqing (Sulige) oil and gas fields.
A description of the tool operating theory, design objectives, unique real-time geosteering display, and logging software is presented. Some results from three years of operations in North America and China will be discussed along with logs and brief case studies.
Double Shoulder Connection Technology Enables Exploration and Production of Ultra-Deep Prospects – Case Histories and Lessons Learned in Xinjiang, China
Authors: Zhao Jingmin , Ma Linhu , Plessis Guillaume , Zha Yongjin , Lu Qiang , Su Jianwen , Liu Peng 
Published: July 2012

Abstract
China oil and gas operators are more and more engaged in the exploration and production of much deeper oil and gas prospects that are pushing the boundaries and limits of the traditional drill stem. A high number of ultra-deep wells (above 7 000 meters) are being drilled in the Xinjiang area. In this part of China, there is a need to improve the hydraulic and mechanical performances of the drilling tubulars used in both large and slim hole size intervals.
A key feature in these products’ performances is the rotary shouldered connection (RSC). API RSC typically requires larger profiled tool joints to provide acceptable torque and tension capacity. However, this increase s pressure losses and restricts fishability. Double shoulder connection (DSC) technology has been successfully used to address this mutually exclusive need for both torque and hydraulics.
CNPC has greatly benefited from their decision to use a first generation double shoulder connection (1st gen DSC) on various sizes of drilling tubulars to successfully drill the deepest exploration well in the Jungar basin as well as numerous exploration and production wells in the Tarim basin.
This paper will first describe the DSC technology, how it contributes to the improved drilling performance, and will present supportive case histories. The 1st gen DSC performed very successfully. Looking ahead, deeper prospects are on the horizon and further enhancements in drill pipe and DSC technology will be necessary. Prospective future options will also be discussed in this paper.