bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance Comparison of Sand Jet Perforating to Explosive Perforating for Multistage Hydraulic Fracturing of Coal Bed Methane Wells
Authors: Dotson Thomas , Gupta Tanya , Sharma Anshit , Marwah Devashish
Published: April 2017

Multi-stage hydraulic fracturing of coal bed methane wells using coiled tubing in Raniganj Coal Bed fields in the eastern part of India has been steadily increasing over the last several years. The completion process of these wells involves various kinds of explosive perforating and sand jet perforating (SJP) prior to the hydraulic fracturing process. Communication with the reservoir is vitally important to the success of the hydraulic fracture. Sand jet perforating is a process that uses high pressure fluid slurry to perforate the casing and cement of an oil or gas well, and extend a cavity into the reservoir. This paper examines the performance of traditional explosive perforating versus sand jet perforating through an examination of case history using both technologies in the same zones. Different operating parameters of sand jet perforating are evaluated. Performance evaluation includes the production of the well.

The paper describes various methods for hydraulic fracturing of coal bed methane formations using a bottom hole assembly with perforator on coiled tubing. The generalized stimulation method for perforating employs the following steps: Run the bottom hole assembly (BHA) to the zone to be treated.Perforate the zone.Perform the hydraulic fracturing of the zone.Isolate the zone.Pull up to the next zone and begin again.

The procedures and process of each completion method will be discussed in detail.

Case history is used from a coal bed methane well in the Raniganji Coal Bed Methane Field, to compare the different parameters of the hydraulic fracturing process in coal beds for traditional explosive perforating versus sand jet perforating. The effectiveness of the treatment process as it relates to production and cost of the treatment is compared.

New techniques for sand jet perforating were employed in the subject wells to improve the communication between the wellbore and the formation. Variations in pressure, and flow through the bottom hole assembly, sand concentration, and total sand delivered are compared and conclusions will be made for optimizing the treatment process.
Degradable Thermoset Polymer Composite for Intervention-Less Downhole Tools
Authors: Khatiwada Suman , Duan Ping , Garza Ramon , Sadana Anil K.
Published: April 2017

Commercially available polymeric frac balls and other downhole tools made with polyglycolic acid (PGA), a thermoplastic, have severe application limitations owing to their low Tg of approximately 104°F as well as high cost. A thermoset polymer composite made from cyanate ester resin has been developed that exhibits hot-water degradability as well as excellent mechanical properties. This polymer composite demonstrates excellent potential for use in structural components of downhole tools for intervention-less operations. A degradable composite with cyanate ester resin with a glass transition temperature (Tg) of 536°F was prepared by adding inorganic fillers and glass fibers. A new process was developed to prepare a bulk molding compound from this composite that enabled fabrication of parts via compression molding. Molded parts were tested for their mechanical properties and for their degradability in water and brines. The composite with one quarter inch chopped glass fiber has a compressive strength of 41.88 ksi, tensile strength of 15.83 ksi, tensile modulus of 3.62 Msi and an elongation-at-break of 0.48%. Composite degradation occurs at 200°F and above, with a higher rate of degradation observed as the temperature increases.
Optimizing Proppant Surface Properties to Improve Formation Flow in Offshore Frac-Packs
Authors: Bestaoui-Spurr Naima , Stanley David , Williams Vanessa , Usie Marty , Nguyen Hanh , Hoffpauir Erik
Published: April 2017

The objective of this study is to introduce a new neutral wettability proppant that improves flow and cleanup of the proppant pack. It is known that the proppant pack permeability is the primary factor that affects the productivity of a fractured well. In such operations, fracturing fluid (cross-linked or linear) is used to deposit the proppant. In order to transport proppant within the fracture, fracturing fluid rheological properties must be attained based on fracture type, job design metrics, formation characteristics, proppant properties and proppant loading. These fluid properties are typically adjusted by using gelling agents and other chemical additives to ensure transport capability. The types and concentration of gelling agents, cross-linkers, and breakers, are known to affect the permeability of the pack. If these fluids are not removed, they build up in the proppant pack. This fluid retention leads to decreased permeability and reduced effective half-length of the fracture. In this paper a neutral wettability proppant that is neither oil wet nor water wet was used to (1) eliminate capillary pressure within the proppant pack and (2) alter the interaction between aqueous/organic (hydrocarbons) and the proppant surfaces by decreasing the intra-molecular interactions between the fluids and the proppant surfaces thus resulting in improved flow compared to native surfaces.

Light weight ceramic proppant was permanently surface modified to a neutral wettability state. This new proppant was evaluated in the laboratory and in the field for compatibility with the fracturing fluid, clean-up properties through the proppant pack and recorded flow back of treatment fluids after a frac-pack operation.

Results indicated that the new proppant surfaces not only reduced water saturation but also improved oil mobility. These observations showed the promises of permanently modifying surfaces as next-generation products for improved flow and decreasing the risk of formation damage due to the fracturing fluids left behind after treatment. When this proppant was applied in a frac-pack completion, flow back was efficient with rapid recovery of all pumped fluids. In this case the surface of the proppant reduced the intra-molecular forces between the proppant and the fracturing fluid, eliminating capillary pressure within the frac-pack and leading to a more efficient and quicker fracturing fluid flow back compared to using proppant in its native state. First oil breakthrough was earlier than other wells in the same area.
Characterization of Wet Gas Flows
Authors: Subramani Hariprasad J. , Sambath Krishnaraj , Rhyne Lee D. , Nadge Pankaj , Vedapuri Damodaran
Published: April 2017

Presently, several large deep water natural gas fields are designed to produce over 1000 MMSCFD of gas with low liquid content <20 BBL/MMSCF. Such deep water facilities are typically comprised of ~8-10" diameter well manifolds and 30-40" in diameter 100 mile long flow lines that are operated at high pressure and temperature conditions. Key CAPEX and OPEX decisions for deep water gas facilities include: wellbore tubing and subsea flow line sizing, subsea flow line routing, pigging frequency, pipeline materials, range of allowable operating rates and large production rate variations, and subsea asset integrity management. Key design decisions require knowledge of variations in flow regime over field life, liquid hold-up in the flow lines, liquid entrainment and sand in the fluids in the subsea facilities that may result in erosion at the high operating limit and sand deposition concerns at low operating limit. Given the scarcity of data at conditions similar to wet gas field conditions, current industry-standard multiphase flow simulators predict flow behaviors with a high degree of uncertainty and hence, are known to have been inadequately validated. This paper presents a unique set of high quality wet gas multiphase flow data in a 16" diameter flow loop operated at ambient conditions including several salient measurements such as pressure drop, liquid hold-up, liquid film velocity as a function of liquid film depth, average liquid film velocity, etc. using state-of-the-art instrumentation.
Study of Anti-Agglomerant Low Dosage Hydrate Inhibitor Performance
Authors: Salmin Davi Costa , Majid Ahmad A. A. , Wells Jonathan , Sloan E. Dendy , Estanga Douglas , Kusinski Greg , Rivero Mayela , Gomes Joseph , Wu David T. , Zerpa Luis E. , Koh Carolyn A.
Published: April 2017

Gas hydrates can form in subsea oil and gas flowlines, where the depths of seawater and ocean conditions provide the thermodynamic environment for hydrate stability. Hydrates present a major flow assurance problem due to the relatively fast timescales at which they can form, grow/agglomerate, and plug a flowline. The common strategy for preventing hydrate formation uses thermodynamic inhibitors (THIs). However, THIs can be cost prohibitive or impractical as the water content in the flowline and its seawater depth increases. Therefore, there is growing interest in the use of alternative hydrate management strategies, such as the injection of low dosage hydrate inhibitors (LDHIs), which are active at considerably lower concentrations than THIs (e.g. 2 vol.% of LDHI versus 50 vol.% of THI). Anti-agglomerants (AAs) are a type of LDHI that prevent agglomeration and allow hydrates to flow as a slurry in oil and gas subsea flowlines. Before field deployment, AAs are screened and selected using laboratory set-ups, mimicking field conditions, in order to evaluate their performance and determine the effective dosage. Current hydrate agglomeration characterization methods implemented in the industry are non-uniform and qualitative, which can lead to conservative recommendations.

In this work, the possibility of quantifying hydrate agglomeration in the presence of AAs is investigated, along with studies of the mechanisms via which AAs may operate. One mineral oil and two crude oils were used with a commercial AA in a high pressure stirred autoclave, equipped with particle imaging probes. Motor current input at a fixed RPM was monitored throughout the experiments and serves as an indicator of relative viscosity of the hydrate slurry. This investigation enabled the development of a comprehensive AA performance evaluation. Hydrate agglomeration was detected and quantified by simultaneous increases in the relative motor current and chord length distribution.
Hydrate Management for Systems with High Salinity Brines at Ultra-High Pressures
Authors: Sum Amadeu K. , Hu Yue , Lee Bo Ram , Karanjkar Prasad , Gomes Joseph , Kusinski Greg
Published: April 2017

Reliable prediction of hydrate phase equilibrium is necessary for operations in deepwater oil and gas production which go beyond hydrate management in pipe flow, such as, setting depth of surface-controlled subsurface safety valve (SCSSV) and identification of effective risk mitigation. There are a number of fields being developed and producing with brines with salt concentration near/at saturation, creating conditions where hydrate formation may lead to salt precipitation. High salinity brines coupled with high pressures (> 10,000 psia) are conditions for which no hydrate phase equilibrium data exist in the open literature. This study, funded by DeepStar®, quantified the impact of high salinity brines in the formation of hydrates by the measurements of hydrate stability conditions in saline systems with under-saturated to saturated concentration through newly designed apparatus and development of correlation based on hydrate suppression temperature,providing reliable prediction results for hydrate phase equilibria in both NaCl and CaCl2 systems up to near-saturated concentrations.
Technology Development Journey of Deepwater Technologies Portfolio
Authors: Batra Rajan , Miranda Crystal. R. , Osako Ichiro
Published: April 2017

In order to meet the challenges of today's evolving oil and gas industry, it is imperative to develop new technologies that can support harsher operational environments such as producing in deepwater safely & reliably. Additionally, the current product price environment adds more complexity and cost challenges to successfully developing new technologies. One of Chevron's key strategies is to differentiate performance through technology. Technology development is performed to reduce uncertainty as well as the risk associated with new technologies. By analysing the system into subsystems and/or components, the risk associated with each new component can be determined and evaluated. Emphasis is placed on subsystems and components with the highest degree of uncertainty because this offers the greatest opportunity for risk reduction. Technology development activities support the company's worldwide operations and major capital projects by developing and deploying technology solutions that drive business growth and efficiency. Chevron's Deepwater business unit is utilizing a portfolio development approach for maturing technologies for a range of Deepwater projects while maintaining enough flexibility to cater to specific project technology requirements. Using a portfolio approach enables better understanding of technology needs and timing, assessment of its current state, and development strategies. The focus of this paper is to describe a process to cost effectively advance a portfolio of technologies for use in offshore deepwater applications. This paper will provide some limited examples to demonstrate the fit-for-purpose technology development approach and tools (i.e. technology gap brainstorm workshop) for technology management in a major capital project environment. In addition, development strategies and lessons learned while managing one of the largest and diverse Deepwater technology portfolios (topsides, subsea and subsurface technologies) will be discussed.
Framework for Prediction of NPT causes using Unstructured Reports
Authors: Priyadarshy Satyam , Taylor Aimee , Dev Ashwani , Venugopal Suresh , Nair Geetha Gopakumar
Published: April 2017

Drilling capital expenditure represents significant portion of any oil and gas project. Drilling investment accounts to about 40% of the cost of the well. Therefore monitoring the health of equipments and processess associated with rigs are critical in bringing down both the cost of the well and the Non Productive Time (NPT). At the moment there are several Key Performance Indicators (KPIs) to monitor NPT but they are reactive in nature. Proactive measures can be taken to avoid NPT and reduce Invisible Lost Time (ILT) by exploiting the power of big data. The scope of this work is to create a framework to predict NPT and ILT causes from massive degree of unstructured data collected during the drilling operations. KPIs and performance values come from numerical metrics. In addition, the industry has also gathered an enormous amount of unstructured data from drilling and other reports. In many industries, Natural Language Processing (NLP) has been used to create value from unstructured data. Upstream reports are not exactly natural language ready reports. Our approach on generating value from these reports has two major steps (1) transforming NLP challenge to Technology language processing (TLP) in drilling context, and (2) classification of NPT causes.

The two-step approach mentioned above results in a framework for mining unstructured reports to detect anomalies like symptoms, events, and actions. A modified NLP, referred here as TLP in the drilling context is used to achieve the first set of data extraction. Furthermore, a predictive model for classification of NPT and ILT causes is performed on the extracted data. The accuracy of these predictive models is an on-going effort, as it is dependent upon the transformation and detection of complex technical language that is inconsistent due to multiple reasons. However, this framework provides a foundation for predicting NPT / ILT during different phases of drilling operations. Use cases that predict attributes related to hole packoff or equipment failure shows the accuracy in the range of 50% to 70% due to a limited amount of extracted technical terms that are relevant. The framework calls for continual improvement of employing deep learning algorithm based on enhanced recovery of correlated technical terms across unstructured reports.

While there are many attempts in using NLP for mining data in E&P sector, in this paper we present a framework for mining unstructured reports that leverage contextual Technology Language processing a step ahead NLP. Our framework incorporates the use of various machine learning algorithms to detect multiple attributes necessary to calculate NPT and ILT, and guides on how to enhance the predictive model.
DeepStar® Global Offshore Technology Development Program 12505 Analysis of Current Technology and Capabilities for Shearing
Authors: Gomes J. , Kusinski G. , Freitas F.
Published: April 2017

This work shares some of the impactful collaborative efforts completed within DeepStar® Global Deepwater Technology Development Program as part of Phase XII projects in X500 Drilling & Completions committees. It will lead to gap identification and provide a current baseline of shearing technologies.

The goal of this research was to survey the BOP industry and gather information about the current state-of-the-art of shearing systems as well as future shearing technologies. The work includes: development of a survey form/table, data collection, and reporting.

A survey table has been developed as part of the present project. The survey table includes: equipment specification (description/type, rated pressure, rams type, etc.), equipment capabilities (water depth rating, compatibility with H2S environment, working temperature range, etc.), equipment options to improve performance (customizable options to enhance shearing performance ram capabilities and/or options for specific applications such as sour service), and testing (repeatability of shearing and durability performance, tested pipe sizes, wall thicknesses, material grades, evidence of testing, etc.).

The desired outcome of the present work includes DeepStar® operators members being allowed access to performance information regarding current state-of-the-art shearing systems summarized in one report. The report will facilitate discussion about the available shearing capabilities as well as future technologies. This document can also be helpful in selecting BOP providers (and/or future technology providers that will be able to operate in 20 ksi pressure conditions).
A Class Based Approach for Utilizing Existing Data to Demonstrate Compliance and Equipment Availability
Authors: Torstensen Are , John Michael
Published: April 2017

Modern drilling systems have a significant number of sensors already integrated into their design. However, this data is generally underutilized with respect to maintaining class notations or periodic survey activities. Analyzing existing data can yield reductions in non-productive time (NPT) in an era where efficiency is the key to success in offshore exploration and production. A Joint Development Project (JDP) with class, rig operator and equipment vendors was established to understand how data analytics may support class requirements while also increasing availability and reliability through condition based monitoring. This paper describes the approach taken in the JDP and the main findings from this real-world example of data analytics applied to current sensor and logging data

Methods, Procedures, Process: The JDP looked to utilize data from 15,000 sensors onboard a drill ship which generated 36 billion data points from the vessels. The sensor data was combined with unstructured data from operational logs and maintenance records to find ways to demonstrate compliance to class and regulatory requirements via digital techniques. Ultimately this approach could remove the need for calendar based inspections while optimizing preventative maintenance tasks and frequencies, both of which increase equipment availability of drilling systems.

The JDP resulted in several significant deliverables. The first is a draft assurance framework as to how data streams can be used by drilling units to support classification requirements without the need for intrusive inspections. The second delivery was a data quality assessment report to demonstrate how data quality can be measured and ensure that there is high confidence in alternative compliance approaches. The third delivery was an optimized preventative maintenance based on analytics of the existing data streams. The fourth deliverable involved creating "Big Data" analytic models (i.e., machine learning) for anomaly detection and failure mitigation.

The JDP demonstrated that data analytics on existing data streams can be used to demonstrate compliance with classification survey requirements and increase availability. An assurance process for data quality creates trust in the analytics before important decisions about inspections and maintenance are made. This is especially true for safety critical systems where machine learning models may be used to mitigate and address reliability issues. This paper describes the approach taken in the JDP and the main findings from this real-world example of data analytics applied to current sensor and logging data.

The project's major novel development issues were the development of an assurance framework, data quality assessment framework and an approach on how sensor based information can be used in this context classification. The use and treatment of sensor data in general is on the exploratory level and leading edge of such applications in the industry.
Offshore Standardization Process and Criteria Development for EPC Project
Authors: Lee Hoseong Daniel , Son Jin-Seong , Kim In-Ho , Jeong Hak-Nam
Published: April 2017

The Offshore Standardization JIP has been progressed with input from participants representing shipyards, oil and gas companies, engineering companies and classification societies. The goal of the JIP is to develop offshore design standards that help to improve safety and increase efficiency. The scope of work includes developing processes and criteria for bulk materials and equipment packages, construction procedures and quality management.

The standard specifications have been developed for the selected components to reduce the construction cost and increase predictability without compromising safety by carrying out a gap analysis among local regulations, industry standards and major offshore project specifications. For verification of the standard specification, risk assessment of the standardized items is performed to identify the critical issues, and business case studies have been performed to evaluate design and construction consequences of the standardization.

The standardization process includes item selection based on project execution risk assessment and lessons learned. The gap analysis has been performed to the various project specifications and compliance to local and global regulations, and class requirement on offshore structures have been reviewed. The applicable criteria for standardization focus on cost, weight, construction efficiency, compatibility, safety requirement and operational maintenance.

The standard specifications for bulk materials, welding procedure qualifications, inspection requirements have been performed for industrial application on EPC project. Proposed standard specifications have been reviewed with feedback process by a technical advisory group within the JIP that is made up of oil and gas and engineering companies. The proposed specifications are accepted by industry as appropriate and will become a guideline for reducing construction cost and inspection time and improving safety and quality through efficient procurement and project management.
Application of Gas Industrial Technologies Offshore
Authors: Saavedra Carlos G.
Published: April 2017

Present an Overview of Available Options for Gas Monetization Offshore at the "OTC Houston 2017" Conference.

The ups and downs of the gas prices associated to the oil glut and the increasing strength of the environmental regulations, the adherence to green aspects of daily living, drastic changes in the world weather due to global warming and the growing respect of nature, make increasingly more difficult, less friendly and less convenient to flare. This presents a big challenge and an opportunity to increase the study and design activities for implementation of alternative gas utilization processes for application onshore and offshore, with particular interest in the later, especially in remote locations of the world. Gas reinjection and transportation by pipelines are the main methods of gas handling as flaring is opposed by governments and the civil society. Reinjection is costly and not always needed and pipelines for long distances could become uneconomical.

The alternative gas handling methods to be summarized in this paper will be floating Liquefied Natural Gas (FLNG), Floating Gas To Liquids (FGTL), floating Methanol (FML), other gas conversion processes and Floating Power Generation or Gas to Wire (FGTW), addressing technologies and processes other than the traditional options, which would enhance the feasibility and enable oil and gas projects in remote areas. This paper will briefly indicate various other alternatives such as Compressed Natural Gas (CNG), Gas-to-Hydrates (GTH), and Gas to ammonia/methanol/DME but will not be formally presented. An evaluation will be made of the gas handling alternatives with regards to: feasibility for remote areas, the technology readiness level (TRL), relative footprint, weights and CAPEX for each alternative.

Several of the options would allow the gas to be transformed into a liquid that could be transported by ship or even spiked into the crude oil for transportation. The transportability of the alternative products in remote areas could alleviate overcoming the challenging distances to the ultimate markets. Other options would allow monetizing the gas at site providing useful product consumption by nearby projects, e.g. GTW or GTL. The paper will describe the value chain of each alternative and describe it including existing and near term applications, technologies utilized, current efforts to improve, highlighting how the project could be enhanced or even enabled.

The necessary further work to bring the technology to fruition will be discussed along with an overview of the current and future gas handling options; a comprehensive evaluation of the TRL, harsh environment inland and offshore cost and impact on projects; and recommended gas handling alternatives for proposed projects.
Acute Ankle Sprain in a Mouse Model: Changes in Knee-Joint Space
Authors: Hubbard-Turner Tricia , Wikstrom Erik A. , Guderian Sophie , Turner Michael J.
Published: April 2017

Context: 

Ankle sprains remain the most common orthopaedic injury. Conducting long-term studies in humans is difficult and costly, so the long-term consequences of an ankle sprain are not entirely known.

Objective: 

To measure knee-joint space after a single surgically induced ankle sprain in mice.

Design: 

Randomized controlled trial.

Setting: 

University research laboratory.

Patients or Other Participants: 

Thirty male mice (CBA/2J) were randomly placed into 1 of 3 surgical groups: the transected calcaneofibular ligament (CFL) group, the transected anterior talofibular ligament/CFL group, or a sham treatment group. The right ankle was operated on in all mice.

Main Outcome Measure(s): 

Three days after surgery, all of the mice were individually housed in cages containing a solid-surface running wheel, and daily running-wheel measurements were recorded. Before surgery and every 6 weeks after surgery, a diagnostic ultrasound was used to measure medial and lateral knee-joint space in both hind limbs.

Results: 

Right medial (P = .003), right lateral (P = .002), left medial (P = .03), and left lateral (P = .002) knee-joint spaces decreased across the life span. The mice in the anterior talofibular ligament/CFL group had decreased right medial (P = .004) joint space compared with the sham and CFL groups starting at 24 weeks of age and continuing throughout the life span. No differences occurred in contralateral knee-joint degeneration among any of the groups.

Conclusions: 

Based on current data, mice that sustained a surgically induced severe ankle sprain developed greater joint degeneration in the ipsilateral knee. Knee degeneration could result from accommodation to the laxity of the ankle or biomechanical alterations secondary to ankle instability. A single surgically induced ankle sprain could significantly affect knee-joint function.
The causes and nature of the June 2016 protests in the city of Tshwane: A practical theological reflection
Authors: Kgatle Mookgo S.
Published: April 2017

South Africa has recently experienced a series of public protests. The common element is that violence is becoming evident in these protests. This article uses the June 2016 protests in the city of Tshwane as an example to address the root causes of such protests. On 20 June 2016, the African National Congress (ANC) announced that the city of Tshwane mayoral candidate for the 3 August 2016 municipal elections in South Africa is the former public works minister and ANC National Executive Committee member, Thoko Didiza. Consequently, public protests in the city of Tshwane emerged immediately after this announcement. These public protests were very violent, such as protesters killed one another, burned buses, looted shops and barricaded roads. The root causes of these violent protests are identified as factionalism, tribalism, sexism, economic exclusion and patronage politics. The purpose of this article is a practical theological reflection on the root causes of June 2016 protests in the city of Tshwane. The main aim of this article is a practical theological solution to the general problem of violent protests.
Disseminated cutaneous histoplasmosis with laryngeal involvement in a setting of immune reconstitution inflammatory syndrome
Authors: Sacoor Mohamed F.
Published: April 2017

Introduction: Histoplasmosis is a systemic mycosis caused by the dimorphic fungus Histoplasma capsulatum. We report a case of disseminated cutaneous histoplasmosis with mucocutaneous involvement in an AIDS patient paradigmatic of the multifaceted nature of the disease, which is an expression of the immune reconstitution inflammatory syndrome (IRIS).Patient presentation: A 39-year-old man presented with a three month history of asymptomatic papules and nodules with necrotic centres involving the centrofacial region. The patient was diagnosed as being HIV-positive a month earlier and was commenced on antiretroviral treatment. Two weeks after the development of skin lesions, the patient complained of a sore throat and hoarseness of his voice. A fibre-optic laryngoscopy and biopsies of the skin, larynx and liver were performed.Management and outcome: The CD4 counts increased from 2 cells/µL to 124 cells/µL, whereas the viral load decreased from one million to less than 20 copies/mL. A fibre-optic laryngoscopy revealed a supraglottitis with ulceration on the epiglottis. Histology of the liver, larynx and sections of the skin demonstrated pandermal necrotising granulomatous inflammation. Grocott-Gomori methenamine silver and Periodic acid–Schiff (PAS) stains revealed a relative paucity of intracellular, narrow-neck budding fungal organisms. Culture findings confirmed the diagnosis of histoplasmosis. The patient was treated with intravenous amphotericin B for two weeks followed by oral itraconazole 100 mg twice a day, with an excellent response to treatment.Conclusion: We present this case to remind clinicians that disseminated histoplasmosis in AIDS patients may occur as an expression of IRIS. A sudden onset of hoarseness with cutaneous lesions in a patient with disseminated disease should alert one to possible laryngeal histoplasmosis. Prompt recognition and treatment will avert the potential fatal complications of this disease.
Projective Plane Bundles Over an Elliptic Curve
Authors: Takahashi Tomokuni
Published: April 2017

We calculate the dimension of cohomology groups for the holomorphic tangent bundles of each isomorphism class of the projective plane bundle over an elliptic curve. As an application, we construct the families of projective plane bundles, and prove that the families are effectively parametrized and complete.
Morphological study of prostate in different age groups of Indian population
Authors: Kayalvizhi I. , Bhoria S. , Khanagwal V. , Narayan R.
Published: April 2017

Introduction: The prostate is a pyramidal shaped, fibromuscular glandular organ which surrounds the prostatic urethra. Three pathologic processes affect the prostate gland: Inflammation, Benign prostatic (Nodular) hyperplasia, and tumours. Of these three, the benign nodular hyperplasia and prostatic carcinoma are prevalent worldwide. Main treatment for both the above mentioned condition till date is surgical extraction of the prostate. A clear concept is required about the morphological features and measurements of prostate as it will play a major role in defining the disease and for the diagnosis. Material and Methods: The present study was conducted in the Department of Anatomy utilizing 50 samples of human prostate, age ranging from 10 to 80 years. The various morphological parameters studied were length, transverse diameter, antero-posterior diameter and weight of prostate. Results: The lowest and highest mean value were 1.76-2.79 cm; 3.35-4.04 cm; 1.65-2.30 cm and 16.8-26.6 gm for length, transverse diameter, antero-posterior diameter and weight respectively. Statistical measurements included mean, standard deviation, range and correlation coeficients of different parameters. Conclusions: Length and transverse diameter of prostate were maximum in the American population, Antero-Posterior diameter was maximum for Bangladeshi and weight was found maximum in Indian population.
Distribution and presentation of Lyme borreliosis in Scotland – analysis of data from a national testing laboratory
Authors: Mavin S , Watson EJ , Evans R
Published: April 2017

This study examines the distribution of laboratory-confirmed cases of Lyme borreliosis in Scotland and the clinical spectrum of presentations within NHS Highland.

Methods

General demographic data (age/sex/referring Health Board) from all cases of Lyme borreliosis serologically confirmed by the National Lyme Borreliosis Testing Laboratory from 1 January 2008 to 31 December 2013 were analysed. Clinical features of confirmed cases were ascertained from questionnaires sent to referring clinicians within NHS Highland during the study period.

Results

The number of laboratory-confirmed cases of Lyme borreliosis in Scotland peaked at 440 in 2010. From 2008 to 2013 the estimated average annual incidence was 6.8 per 100,000 (44.1 per 100,000 in NHS Highland). Of 594 questionnaires from NHS Highland patients: 76% had clinically confirmed Lyme borreliosis; 48% erythema migrans; 17% rash, 25% joint, 15% neurological and 1% cardiac symptoms. Only 61% could recall a tick bite.

Conclusion

The incidence of Lyme borreliosis may be stabilising in Scotland but NHS Highland remains an area of high incidence. Lyme borreliosis should be considered in symptomatic patients that have had exposure to ticks and not just those with a definite tick bite.
Utility and prevalence of imaging for underlying cancer in unprovoked pulmonary embolism
Authors: Homewood R , Medford ARL
Published: April 2017

Current guidelines state that patients over 40 years of age with a first unprovoked pulmonary embolism should be offered limited screening for possible cancer and considered for intensive screening (abdomino-pelvic computed tomography and mammography), despite no evidence for the latter. The aim of this study was to evaluate the clinical utility and cost of intensive screening in routine clinical practice.

Methods

All patients diagnosed with a first unprovoked pulmonary embolism between January 2014 and June 2014 in a single large UK teaching hospital were included. The information management department searched for patients with an International Classification of Diseases 10 discharge diagnosis of pulmonary embolism and limited to ‘acute pulmonary embolism with/without cor pulmonale'. Only patients with unprovoked pulmonary embolism were included. Patients with chronic medical conditions predisposing to pulmonary embolism were excluded. NHS costs were obtained from the Trust Finance Department. These costs were used to generate the costs of limited versus intensive screening, and then scaled up using adult population census information and assuming the same incidence of idiopathic pulmonary embolism to estimate the annual NHS cost of intensive screening.

Results

Ninety-two patients were diagnosed with pulmonary embolism, and 25 met the inclusion criteria. Clinical examination was often incomplete (84%). Limited screening was often missed (urinalysis 100%, serum calcium 64%). Intensive screening was performed in the majority of cases (68%, all abdomino-pelvic computed tomography with no cancer detected) with an £88 excess cost per patient.

Conclusion

Intensive screening in first unprovoked pulmonary embolism has a low yield, is costly and should not replace thorough clinical examination and basic screening.
A retrospective study of seven-day consultant working: Reductions in mortality and length of stay
Authors: Leong KS , Titman A , Brown M , Powell R , Moore E , Bowen-Jones D
Published: April 2017

Weekend admission is associated with higher in-hospital mortality than weekday admission. Whether providing enhanced weekend staffing for acute medical inpatient services reduces mortality or length of stay is unknown

Methods

This paper describes a retrospective analysis of in-hospital mortality and length of stay before and after introduction of an enhanced, consultant-led weekend service in acute medicine in November 2012. In-hospital mortality was compared for matching admission calendar months before and after introduction of the new service, adjusted for case volume. Length of stay and 30-day post-discharge mortality were also compared; illness severity of patients admitted was assessed by cross-sectional acuity audits.

Results

Admission numbers increased from 6,304 (November 2011–July 2012) to 7,382 (November 2012–July 2013), with no change in acuity score in elderly medical patients but a small fall in younger patients. At the same time, however, a 57% increase in early-warning score triggered calls was seen in 2013 (410 calls vs 262 calls in 2012; p<0.01). Seven-day consultant working was associated with a reduction in in-hospital mortality from 11.4% to 8.8% (p<0.001). Mortality within 30 days of discharge fell from 2.4% to 2.0% (p=0.12). Length of stay fell by 1.9 days (95% CI 1.1–2.7; p=0.004) for elderly medicine wards and by 1.7 days (95% CI 0.8–2.6; p=0.008) for medical wards. Weekend discharges increased from general medical wards (from 13.6% to 18.8%, p<0.001) but did not increase from elderly medicine wards.

Conclusions

Introduction of an enhanced, consultant-led model of working at weekends was associated with reduced in-hospital and 30-day post discharge mortality rates as well as reduced length of stay. These results require confirmation in rigorously designed prospective studies.
Dilated cardiomyopathy: A preventable presentation of DiGeorge Syndrome
Authors: Jamieson A , Smith CJ
Published: April 2017

Patients with cardiac failure require careful evaluation to determine the precise nature of the cause of their illness. Genetic causes of dilated cardiomyopathy are well known but inherited conditions may lead to unexpected consequences through intermediate mechanisms not readily recognised as a feature of the inherited disorder. We describe a case of dilated cardiomyopathy resulting from prolonged hypocalcaemia due to previously undiagnosed hypoparathyroidism resulting from DiGeorge Syndrome and describe the features of this case and the treatment of hypoparathyroidism.
The secular and the supernatural: Madness and psychiatry in the short stories of Muriel Spark
Authors: Beveridge AW
Published: April 2017

Edinburgh-born Muriel Spark is one of modern Scotland's greatest writers. Examination of her work reveals that the subjects of madness and psychiatry are recurrent themes in her writing. She herself had a mental breakdown when she was a young woman and she took an interest in the world of psychiatry and psychoanalysis. In her short stories, Spark approaches the subject of madness in a variety of ways: she relates it to the supernatural; to writing fiction; and to religion. She frequently juxtaposes secular and supernatural explanations of mental disturbance. Spark adopts a sceptical and, at times, mocking view of psychiatrists and psychiatric treatment. Both psychoanalysis and pills are seen as problematic.
Enhanced hydrophobicity and volatility of submicron aerosols under severe emission control conditions in Beijing
Authors: Wang Yuying , Zhang Fang , Li Zhanqing , Tan Haobo , Xu Hanbing , Ren Jingye , Zhao Jian , Du Wei , Sun Yele
Published: April 2017

Abstract. A series of strict emission control measures was implemented in Beijing and the surrounding seven provinces to ensure good air quality during the 2015 China Victory Day parade, rendering a unique opportunity to investigate the anthropogenic impact of aerosol properties. Submicron aerosol hygroscopicity and volatility were measured during and after the control period using a hygroscopic and volatile tandem differential mobility analyzer (H/V-TDMA) system. Three periods, namely the control clean period (Clean1), the non-control clean period (Clean2), and the non-control pollution period (Pollution), were selected to study the effect of the emission control measures on aerosol hygroscopicity and volatility. Aerosol particles became more hydrophobic and volatile due to the emission control measures. The hygroscopicity parameter (κ) of 40–200 nm particles decreased by 32.0–8.5 % during the Clean1 period relative to the Clean2 period, while the volatile shrink factor (SF) of 40–300 nm particles decreased by 7.5–10.5 %. The emission controls also changed the diurnal variation patterns of both the probability density function of κ (κ-PDF) and the probability density function of SF (SF-PDF). During Clean1 the κ-PDF showed one nearly hydrophobic (NH) mode for particles in the nucleation mode, which was likely due to the dramatic reduction in industrial emissions of inorganic trace gases. Compared to the Pollution period, particles observed during the Clean1 and Clean2 periods exhibited a more significant nonvolatile (NV) mode throughout the day, suggesting a more externally mixed state particularly for the 150 nm particles. Aerosol hygroscopicities increased as particle sizes increased, with the greatest increases seen during the Pollution period. Accordingly, the aerosol volatility became weaker (i.e., SF increased) as particle sizes increased during the Clean1 and Clean2 periods, but no apparent trend was observed during the Pollution period. Based on a correlation analysis of the number fractions of NH and NV particles, we found that a higher number fraction of hydrophobic and volatile particles during the emission control period.
Influence of fuel ethanol content on primary emissions and secondary aerosol formation potential for a modern flex-fuel gasoline vehicle
Authors: Timonen Hilkka , Karjalainen Panu , Saukko Erkka , Saarikoski Sanna , Aakko-Saksa Päivi , Simonen Pauli , Murtonen Timo , Dal Maso Miikka , Kuuluvainen Heino , Bloss Matthew , Ahlberg Erik , Svenningsson Birgitta , Pagels Joakim , Brune William H. , Keskinen Jorma , Worsnop Douglas R. , Hillamo Risto , Rönkkö Topi
Published: April 2017

Abstract. The effect of fuel ethanol content (10, 85 and 100 %) on primary emissions and on subsequent secondary aerosol formation was investigated for a Euro 5 flex-fuel gasoline vehicle. Emissions were characterized during a New European Driving Cycle (NEDC) using a comprehensive set-up of high time-resolution instruments. A detailed chemical composition of the exhaust particulate matter (PM) was studied using a soot particle aerosol mass spectrometer (SP-AMS), and secondary aerosol formation was studied using a potential aerosol mass (PAM) chamber. For the primary gaseous compounds, an increase in total hydrocarbon emissions and a decrease in aromatic BTEX (benzene, toluene, ethylbenzene and xylenes) compounds was observed when the amount of ethanol in the fuel increased. In regard to particles, the largest primary particulate matter concentrations and potential for secondary particle formation was measured for the E10 fuel (10 % ethanol). As the ethanol content of the fuel increased, a significant decrease in the average primary particulate matter concentrations over the NEDC was found. The PM emissions were 0.45, 0.25 and 0.15 mg m−3 for E10, E85 and E100, respectively. Similarly, a clear decrease in secondary aerosol formation potential was observed with a larger contribution of ethanol in the fuel. The secondary-to-primary PM ratios were 13.4 and 1.5 for E10 and E85, respectively. For E100, a slight decrease in PM mass was observed after the PAM chamber, indicating that the PM produced by secondary aerosol formation was less than the PM lost through wall losses or the degradation of the primary organic aerosol (POA) in the chamber. For all fuel blends, the formed secondary aerosol consisted mostly of organic compounds. For E10, the contribution of organic compounds containing oxygen increased from 35 %, measured for primary organics, to 62 % after the PAM chamber. For E85, the contribution of organic compounds containing oxygen increased from 42 % (primary) to 57 % (after the PAM chamber), whereas for E100 the amount of oxidized organics remained the same (approximately 62 %) with the PAM chamber when compared to the primary emissions.
The influence of sea- and land-breeze circulations on the diurnal variability of precipitation over a tropical island
Authors: Zhu Lei , Meng Zhiyong , Zhang Fuqing , Markowski Paul M.
Published: April 2017

Abstract. This study examines the diurnal variation of precipitation over Hainan Island in the South China Sea using gauge observations from 1950 to 2010 and CMORPH satellite estimates from 2006 to 2015, as well as numerical simulations. Precipitation is most significant from April to October, and exhibits a strong diurnal cycle resulting from land/sea breeze circulations. More than 60 % of the total annual precipitation over the island is attributable to the diurnal cycle, with a significant monthly variability as well. The CMORPH and gauge datasets agree well, except that the CMORPH data underestimates precipitation and has a 1-h delay of peaks. The diurnal cycle of the rainfall and the related land/sea breeze circulations during May and June were well captured by convection-allowing numerical simulations with WRF, which were initiated from 10-year average ERA-interim reanalysis, despite slightly overall overestimation and 1-h delay of the rainfall peak. The diurnal precipitation is due to a diurnal cycle of moist convection, which initiates around noontime owing to low-level convergence associated with the sea breeze circulation. The precipitation intensifies rapidly thereafter and peaks in the afternoon with the collisions of sea breeze fronts from different sides of the island. Cold pools of the convective storms contribute to the inland propagation of the sea breeze. The precipitation dissipates quickly in the evening owing to the cooling and stabilization of the lower troposphere and decrease of boundary-layer moisture. Interestingly, the rather high island orography is not a dominant factor in the diurnal variation of the precipitation over the island.