bluuebunny/crossref_metadata_2025 huggingface dataset:
Multifrequency full-waveform sonic logging in the screened interval of a large-diameter production well
Authors: Almalki Majed , Harris Brett , Dupuis J. Christian
Published: September 2013

A set of field experiments using multiple transmitter center frequencies was completed to test the application potential of low-frequency full-waveform sonic logging in large-diameter production wells. Wireline logs were acquired in a simple open drillhole and a high-yield large diameter production well completed with wire-wound sand screens at an aquifer storage and recovery site in Perth, Western Australia. Phase-shift transform methods were applied to obtain phase-velocity dispersion images for frequencies of up to 4 kHz. A 3D representation of phase-velocity dispersion was developed to assist in the analysis of possible connections between low-frequency wave propagation modes and the distribution of hydraulic properties. For sandstone intervals in the test well, the highest hydraulic conductivity intervals were typically correlated with the lowest phase velocities. The main characteristics of dispersion images obtained from the sand-screened well were highly comparable with those obtained at the same depth level in a nearby simple drillhole open to the formation. The sand-screened well and the open-hole displayed an expected and substantial difference between dispersion in sand- and clay-dominated intervals. It appears that for clay-dominated formations, the rate of change of phase velocity can be associated to clay content. We demonstrated that with appropriate acquisition and processing, multifrequency full-waveform sonic logging applied in existing large-diameter sand-screened wells can produce valuable results. There are few wireline logging technologies that can be applied in this setting. The techniques that we used would be highly suitable for time-lapse applications in high-volume production wells or for reassessing formation properties behind existing historical production wells.
President's Page
Authors: Monk Dave
Published: September 2013

My term as president has been short. With the Annual Meeting of 2012 being in November and the 2013 meeting being in September, I have found myself as president for only nine months. Much shorter than my predecessor, Bob Hardage, who passed onto me a Society with new bylaws, and a reinvigorated Council as well as a Board of Directors much bigger than the previous Executive Committees. Bob continued to serve on the Board, as past president, and I have been glad of his advice and guidance during the year.
SEAM Update
Authors: Oristaglio Michael
Published: September 2013

The Foothills Model is the third, and final, digital Earth model being built by the SEAM Phase II consortium on Land Seismic Challenges. Two SEAM updates earlier this year covered the other Phase II models: the Unconventional Model, which contains shale-gas reservoirs set in a stratigraphic section resembling the Arkoma basin of North America (see the March 2013 issue of TLE) and the Arid Model, which places these same shale reservoirs underneath a 500-m thick surface layer with desert features patterned after the karsts, wadis, and topography of the Saudi Arabian peninsula (see the June 2013 issue of TLE). This update describes the Foothills Model, which, as suggested by the name, was designed to represent challenges of seismic exploration in mountainous regions.
An introduction to this special section: Full-waveform inversion and the way forward
Authors: Guitton Antoine , Alkhalifah Tariq
Published: September 2013

Lost in the endless valleys and hills of the full-waveform inversion (FWI) misfit functional, we tend to stop and wonder: Are we heading in the right direction? Are we in the right valley? Or within a bigger context, is FWI the way to go? The practice of updating an Earth model and generating synthetic data from it that we can compare to the field data is an appealing concept. If the two data sets (the modeled and field) match, using some measure of misfit, we might have found a good Earth model. This process depends on our ability to fully replicate (simulate) the physics of wave propagation inside the Earth. In principle, our field data carry information from every point in the Earth, but these data are also constrained by the geometry of seismic acquisition.
Data-domain and image-domain wavefield tomography
Authors: Díaz Esteban , Sava Paul , Yang Tongning
Published: September 2013

Waveform inversion (FWI) requires a good starting model and/or data at very low frequency (<1 Hz) for convergence. However, this is not a necessary condition, but an artifact of the objective function defined using differences of observed and simulated data. Image-domain tomographic methods using the same wavefields and wave equations can converge to a reasonable solution from poor starting models and without long-offset and/or low-frequency data. Cascading image-domain and data-domain wavefield tomography eliminates the need for extremely low-frequency in the acquired data.
Frugal full-waveform inversion: From theory to a practical algorithm
Authors: Herrmann Felix J. , Hanlon Ian , Kumar Rajiv , Leeuwen Tristan van , Li Xiang , Smithyman Brendan , Wason Haneet , Calvert Andrew J. , Javanmehri Mostafa , Takougang Eric Takam
Published: September 2013

As conventional oil and gas fields are maturing, our profession is challenged to come up with the next-generation of more and more sophisticated exploration tools. In exploration seismology this trend has let to the emergence of wave-equation-based inversion technologies such as reverse time migration and full-waveform inversion. While significant progress has been made in wave-equation-based inversion, major challenges remain in the development of robust and computationally feasible workflows that give reliable results in geophysically challenging areas that may include ultralow shear-velocity zones or high-velocity salt. Moreover, subsalt production carries risks that need mitigation, which raises the bar from creating subsalt images to inverting for subsalt overpressure.
Subsurface model estimation using Laplace-domain inversion methods
Authors: Shin Changsoo , Ha Wansoo , Kim Youngseo
Published: September 2013

Laplace-domain full-waveform inversion is used to estimate subsurface macro-velocity models from seismic data. This method can be applied to marine or land data and combined with the frequency-domain technique for a higher resolution. Laplace-domain full-waveform inversion is robust with respect to a lack of low-frequency information in the seismic data. This method can be used as an alternative or complement to conventional full-waveform inversion methods; however, several important aspects must be considered when inverting data in the Laplace domain. This article provides an overview of the Laplace-domain full-waveform inversion method and related techniques that have been developed to date.
Simultaneous-source full-wavefield inversion
Authors: Bansal Rishi , Krebs Jerry , Routh Partha , Lee Sunwoong , Anderson John , Baumstein Anatoly , Mullur Anoop , Lazaratos Spyros , Chikichev Ivan , McAdow David
Published: September 2013

Seismic data acquired for exploration, development or production surveys are typically densely sampled, often driven by high-resolution imaging objectives. It is common to have tens or hundreds of thousands of shots in a marine survey. This poses a significant computational challenge for full-wavefield inversion (FWI), because each shot needs to be simulated individually. Even with the fastest computing systems, the cost increases tremendously while incorporating complex physics and inverting higher frequencies in the data. For example, the cost of 3D finite-difference elastic simulation is roughly 50 times the cost of acoustic simulation. And it increases by a factor of 16 if the frequency of the simulation is doubled. For 3D acoustic wavefield simulation, the cost is 256 times higher at 40 Hz than at 10 Hz. Therefore, large-scale 3D application of FWI is a challenging problem. The method involves several forward modeling and gradient computations of each field gather by numerically solving the wave equation. Even in a large computer environment, for an average seismic survey, the turnaround time for FWI can be significant. Furthermore, most FWI applications require several trial runs to choose suitable parameters to tune the inversion for a stable solution. The key to making FWI practical is to reduce the number of individual shots, thereby providing computational savings for both forward modeling and gradient computations.
Ultralong-offset data acquisition can complement full-waveform inversion and lead to improved subsalt imaging
Authors: Vigh Denes , Moldoveanu Nick , Jiao Kun , Huang Wei , Kapoor Jerry
Published: September 2013

Full-waveform inversion (FWI) has proved itself as a valuable tool for updating and improving the accuracy of subsurface velocity models. For optimum performance, particularly in complex geological environments such as subsalt targets in the Gulf of Mexico (GOM), FWI requires 3D seismic data containing low frequencies and long offsets. For onshore seismic surveys, it is relatively straightforward and cost-effective to record long-offset data; however, for offshore surveys it can incur the additional cost of ocean-bottom cable (OBC) acquisition or multivessel towed-streamer techniques. The recent introduction of dual-coil-shooting multivessel full-azimuth acquisition has provided a highly efficient method of delivering marine 3D seismic data sets with long offsets. Tests using synthetic data and a real GOM dual-coil acquisition data set with full-azimuth distribution and long (up to 14.3-km) offsets demonstrate significant potential for improving the accuracy of velocity models and the reliability of the resulting depth images. The results indicate that the long offsets and low frequencies provided by the dual-coil acquisition method are of particular benefit in helping FWI to enhance the shallow section of the model. Furthermore, lower frequencies and longer offsets mitigate the sensitivity of the inversion process to the initial velocity model by enabling FWI to update the low-wavenumber component of the velocity model.
Geometric bore variations and their harmonic nuances in musical instruments
Authors: Pershing Harrison R.
Published: September 2013

Pressure waves, whether generated by humans or by natural processes, are a fundamental tool in the exploration of the Earth. The interaction between pressure waves and subsurface structures is complex, and diagnosing structure from observations of pressure waves is an active area of research. Many early studies of pressure waves and harmonic oscillations were motivated by a fascination with musical sounds, and musical instruments are still an excellent modeling system for exploring pressure-wave dynamics.
Change proposed in membership requirements
Authors: Dave Monk
Published: September 2013

Our Bylaws state that one of the roles of the president is to present to the Council “matters for which Council approval is sought.” This includes changes to the Bylaws of the Society, which must be approved by the Council. At our last Annual Meeting, we established a new governance structure, so it is not surprising that this year I will put before the Council suggested “housekeeping” changes to the Bylaws, which have been found during the year to clean up the Bylaws and keep them in line with what is obvious practice. These changes follow.
GEOPHYSICS BRIGHT SPOTS
Authors: Stockwell John W.
Published: September 2013

Why read Geophysics? This month's Bright Spots are an eclectic mix of integrated geophysics and innovative techniques for geophysical data processing and modeling, theory and case studies.
Reviews
Authors: Avakian Robert
Published: September 2013

The Lost World of Fossil Lake: Snapshots from Deep Time, by L. Grande, ISBN13: 978-0-226-92296-6, University of Chicago Press, 2013 432 pp., US $45.00. Solved Problems in Geophysics, by E. Buforn, C. Pro, and A. Udías, ISBN13: 978-1-107-60271-7, Cambridge University Press, 2012, 366 pp., US $50 (e-book available).
The Digital Library goes mobile
Authors: Farley Isaac
Published: September 2013

Right this second, tens if not hundreds of millions of people around the world are searching, skimming, downloading, and sharing digital offerings on mobile devices that fit in a pocket. SEG members are included in these numbers; we are aware of this fact. Thus, it should be no surprise that we are happy to introduce the mobile SEG Digital Library.
Solvent-dependent Photoisomerization Quantum Yield of 2-Phenylazo-1-alkyl-3-methylimidazolium Cations in Ionic Liquids under S1(n, π*) Excitation
Authors: Yoshida Tsuyoshi , Monji Tomoo , Kawamori Daiki , Akai Nobuyuki , Shibuya Kazuhiko , Kawai Akio
Published: September 2013

Photoisomerization quantum yields (ΦE–Z) of phenylazo-substituted imidazolium cations, which are counterparts of recently developed photochromic ionic liquids, were measured under S1(n, π*) excitation. The ΦE–Z values are lower in imidazolium-type ionic liquids than those in conventional solvents and in tert-alkylammonium-type ionic liquids. This observation was argued based on solute–solvent complex formation at imidazolium rings.
Training and Supervision of Residential Staff in Community-based Treatment Facilities
Authors: Axer Henryk , Donohue Michael , Moore David , Welch Tom
Published: September 2013

Abstract: Oregon's Public Mental Health System employs a large number of unlicensed personnel with limited formal mental health training, both in state hospitals and in residential treatment programs. These mental health paraprofessionals often have the most frequent and direct contact with seriously mentally ill individuals, and therefore have significant impact on their lives. The authors describe organization as well as clinical and administrative supervision of a mostly paraprofessional team working with severely and persistently mentally ill (SPMI) criminal offenders. The purpose of this article is to delineate the most important factors allowing for effective and safe utilization of the fairy unsophisticated personnel in the community based-secure treatment facility for individuals under criminal commitment, conditionally released from Oregon State Hospital.
Stress coping mechanisms in patients with chronic dermatoses.
Authors: Korabel Hanna , Grabski Bartosz , Dudek Dominika , Jaworek Andrzej , Gierowski Józef , Kiejna Andrzej , Wojas-Pelc Anna
Published: September 2013

Aim of the study

The results of numerous studies of today confirm that persons suffering from psychosomatic disorders are not able to effectively cope with stress. The experience of stress is also frequently combined with the occurrence or aggravation of various skin diseases.
The goal of our study was to identify the predominant ways of coping with stress in the group of patients with chronic dermatoses.

Subject or material and methods

The group under study included patients receiving treatment in the Dermatology Clinic of Collegium Medicum, Jagiellonian University. They were either hospitalized patients or those who came for control examinations at the Outpatient Clinic. Evaluation of the forms of coping with stress was conducted with the help of the Endler and Parker Questionnaire – CISS.

Results

stress. They significantly more often apply the style of coping focused on avoiding (p-value= 0.0056). It also turned out that the patients in the dermatological groups manifested a constant tendency to get involved in vicarious activities (p-value=0.0247).

Discussion

The results of the presented study indicate that there is a statistically significant difference between the patients with dermatological disorders and those in the control group as regards their ways of coping with stress.

Conclusions

The results obtained in the discussed study may be a starting point for designing a complex support for the patients with skin diseases. The therapeutic technique that may prove helpful for this group of patients is the cognitive-behavioral therapy (CTB).
Television: Horror’s ‘original’ home
Authors: Schmidt Lisa
Published: September 2013

Unquestionably, horror has always existed on television. Nevertheless, a number of scholars and critics have argued that the horror genre belongs properly to film, that television is too much a product of the industrial conditions that both regulate and create it to achieve ‘true’ horror. Not only is this position no longer viable (if it ever was) but it is based upon an assumption about what the horror genre is or should be. If we consider modern horror in relation to the Gothic novel and its immediate counterparts the stage melodrama and the sensation novel/drama, it soon becomes clear that television has a special and perhaps unique affinity with the genre as cultural and literary product. Television can do what film cannot, through its historical and contemporary strengths in the deployment of melodrama, particularly in serialized form. Through seriality, television horror reveals the melodramatic nature of the genre. Moreover, it (re)creates that original horror in a way that speaks, perhaps, to some of horror’s less appreciated pleasures and less acknowledged audiences. This article examines this claim through a sketch of Gothic and melodramatic traditions, tracing these through sensation novels, early film melodrama and ultimately contemporary serialized genre television, particularly the CW series Supernatural and The Vampire Diaries. In both series, the Gothic elements are manifested in the show’s manipulation of any and all elements of fantastic lore alongside plentiful gore and intense family drama.
The truth is in their faces: MTV’s Fear and the rise of ‘Personal Affect’ in paranormal horror
Authors: Zolides Andrew
Published: September 2013

Looking to capture the popularity and excitement surrounding the first truly successful ‘found footage’ horror film The Blair Witch Project (1999), in 2000 MTV began airing Fear, a reality competition-style television series that found contestants completing dares while exploring a haunted location to win money. Continuing the early tradition of MTV pushing boundaries and inventing formulas, Fear utilized the aesthetics made popular in Blair Witch and combined them with the increasingly popular reality competition format. While this union of seemingly disparate concepts did not last long in its own right, Fear set the standard for future paranormal reality television shows in terms of affective programming. Fear had a unique relationship between producer, consumer and technology, as the contestants filmed the show themselves, as well as utilizing surveillance cameras. This results in a more personal, amateur presentation that is indicative of a larger cultural trend in the twenty-first century, with a convergence of audience and performer, consumer and producer. Most interesting for Fear is that these lines are blurred not by ideology, but affect.
‘Make Me Believe!’: Ghost-hunting technology and the postmodern fantastic
Authors: Lauro Sarah Juliet , Paul Catherine
Published: September 2013

Contemporary representations of the paranormal are framed both as fiction and reality. Many primetime programmes showcase paranormal phenomena while positing themselves as documentary television. This article looks at one subgenre of paranormal reality shows, ghost hunting, and specifically at its uses of technology as a way of positioning the art of ghost hunting as a scientific endeavour. At the same time, we consider the rhetorical technologies that are put into place, not only in such ghost-hunting programmes, but also in the ghost tourism industry, in order to, as one of the brothers on the show Ghost Lab said defiantly to the invisible specters with whom he was trying to communicate: ‘Make me believe!’ Putting paranormal reality television in dialogue with historical records of the spiritualist movement of the nineteenth and early twentieth centuries, we explore the differences between the Gothic, Victorian, Modern and (what we might call) Postmodern Fantastic: contemporary paranormal narratives that offer its viewers the ability to sustain the sense of ambivalence produced in the Fantastic indefinitely, by allowing them to believe without being believers.
On a congruence prime criterion for cusp forms on GL2 over number fields
Authors: Namikawa Kenichi
Published: September 2013

Let f be a normalized Hecke eigenform on GL2 over a number field F and let 𝔓 be a prime ideal of a number field which contains the Galois closure of the number field which is generated by all Fourier coefficients of f over F. In this paper, we give a sufficient condition for 𝔓 to be a congruence prime for f.
This criterion is a generalization of congruence prime criteria which were known for the case of elliptic cusp forms by Hida,
for the case where F is an imaginary quadratic field by Urban
and for the case of Hilbert cusp forms by Ghate and Dimitrov to arbitrary number fields.
Artin's conjecture and systems of diagonal equations
Authors: Wooley Trevor D.
Published: September 2013

We show that Artin's conjecture concerning p-adic solubility of Diophantine equations fails for infinitely many systems of r homogeneous diagonal equations whenever r ≥ 2.
Stressed to death – mechanisms of ER stress-induced cell death
Authors: Sovolyova Natalia , Healy Sandra , Samali Afshin , Logue Susan E.
Published: September 2013

The endoplasmic reticulum (ER) is a highly dynamic organelle of fundamental importance present in all eukaryotic cells. The majority of synthesized structural and secreted proteins undergo post-translational modification, folding and oligomerization in the ER lumen, enabling proteins to carry out their physiological functions. Therefore, maintenance of ER homeostasis and function is imperative for proper cellular function. Physiological and pathological conditions can disturb ER homeostasis and thus negatively impact upon protein folding, resulting in an accumulation of unfolded proteins. Examples include hypoxia, hypo- and hyperglycemia, acidosis, and fluxes in calcium levels. Increased levels of unfolded/misfolded proteins within the ER lumen triggers a condition commonly referred to as ‘ER stress’. To combat ER stress, cells have evolved a highly conserved adaptive stress response referred to as the unfolded protein response (UPR). UPR signaling affords the cell a ‘window of opportunity’ for stress resolution however, if prolonged or excessive the UPR is insufficient and ER stress-induced cell death ensues. This review discusses the role of ER stress sensors IRE1, PERK and ATF6, describing their role in ER stress-induced death signaling with specific emphasis placed upon the importance of the intrinsic cell death pathway and Bcl-2 family regulation.
The role of GRASPs in morphological alterations of Golgi apparatus: mechanisms and effects
Authors: Ji Guang , Ji Hui , Mo Xiaoye , Li Ting , Yu Yaduo , Hu Zhiping
Published: September 2013

The Golgi apparatus (GA) is a pivotal organelle in cell metabolism, functioning not only in the processing and transportation of cargoes but also in ion homeostasis, cell apoptosis, and stress sensing. We are interested in the intricate role of GA and the recently present novel concept of ‘GA stress’. GA shows various morphological alterations in many neurodegenerative diseases and cell apoptosis induced by biochemical reagents, mechanisms in which oxidative stress is strongly involved. In turn, the structural changes and morphological alterations of the GA could also transduce stress signals. Therefore, besides the biochemical changes, more attention should be paid to the morphological alterations of the GA itself during pathological processes and diseases. The Golgi reassembly and stacking proteins (GRASPs) have been identified as important components acting in the transformation of Golgi structure, and they may thus affect the Golgi functions and cell behavior. In this review, we will discuss the intricate role of the GRASPs in remodeling the GA morphology and focus on their mechanisms and effects in the processes of Golgi stacking, mitosis, cell apoptosis, and cargo secretion. We would also like to provide a further prospective of their potential biological values in neurodegenerative diseases.
Testosterone deficiency is associated with increased risk of mortality and testosterone replacement improves survival in men with type 2 diabetes
Authors: Muraleedharan Vakkat , Marsh Hazel , Kapoor Dheeraj , Channer Kevin S , Jones T Hugh
Published: September 2013

Objective

Men with type 2 diabetes are known to have a high prevalence of testosterone deficiency. No long-term data are available regarding testosterone and mortality in men with type 2 diabetes or any effect of testosterone replacement therapy (TRT). We report a 6-year follow-up study to examine the effect of baseline testosterone and TRT on all-cause mortality in men with type 2 diabetes and low testosterone.

Research design and methods

A total of 581 men with type 2 diabetes who had testosterone levels performed between 2002 and 2005 were followed up for a mean period of 5.8±1.3 s.d. years. Mortality rates were compared between total testosterone >10.4 nmol/l (300 ng/dl; n=343) and testosterone ≤10.4 nmol/l (n=238). The effect of TRT (as per normal clinical practise: 85.9% testosterone gel and 14.1% intramuscular testosterone undecanoate) was assessed retrospectively within the low testosterone group.

Results

Mortality was increased in the low testosterone group (17.2%) compared with the normal testosterone group (9%; P=0.003) when controlled for covariates. In the Cox regression model, multivariate-adjusted hazard ratio (HR) for decreased survival was 2.02 (P=0.009, 95% CI 1.2–3.4). TRT (mean duration 41.6±20.7 months; n=64) was associated with a reduced mortality of 8.4% compared with 19.2% (P=0.002) in the untreated group (n=174). The multivariate-adjusted HR for decreased survival in the untreated group was 2.3 (95% CI 1.3–3.9, P=0.004).

Conclusions

Low testosterone levels predict an increase in all-cause mortality during long-term follow-up. Testosterone replacement may improve survival in hypogonadal men with type 2 diabetes.
Central effects of GLP-1: new opportunities for treatments of neurodegenerative diseases
Authors: Hölscher Christian
Published: September 2013

The incretin hormone glucagon-like peptide 1 (GLP-1) has many effects in the body. It is best known for the ‘incretin effect’, facilitating insulin release from the pancreas under hyperglycaemic conditions. Building on this, GLP-1 mimetics have been developed as a treatment for type 2 diabetes. In the course of monitoring of patients, it has become apparent that GLP-1 mimetics have a range of other physiological effects in the body. In preclinical trials, a substantial body of evidence has been built that these mimetics have neuroprotective and anti-inflammatory effects. GLP-1 also has very similar growth-factor-like properties to insulin, which is presumably the underlying basis of the neuroprotective effects. In preclinical studies of Alzheimer's disease (AD), Parkinson's disease (PD), stroke and other neurodegenerative disorders, it has been shown that most GLP-1 mimetics cross the blood–brain barrier and show impressive neuroprotective effects in numerous studies. In animal models of AD, GLP-1 mimetics such as exendin-4, liraglutide and lixisenatide have shown protective effects in the CNS by reducing β-amyloid plaques, preventing loss of synapses and memory impairments, and reducing oxidative stress and the chronic inflammatory response in the brain. In animal models of PD, exendin-4 showed protection of dopaminergic neurons in the substantia nigra and prevention of dopamine loss in the basal ganglia while preserving motor control. These encouraging findings have spawned several clinical trials, some of which have shown encouraging initial results. Therefore, GLP-1 mimetics show great promise as a novel treatment for neurodegenerative conditions.
Medication Adherence and Health Care Utilization in Pediatric Chronic Illness: A Systematic Review
Authors: McGrady Meghan E. , Hommel Kevin A.
Published: September 2013

BACKGROUND AND OBJECTIVE:

Advanced understanding of modifiable predictors of health care use in pediatric chronic illness is critical to reducing health care costs. We examined the relationship between medication non-adherence and health care use in children and adolescents who have a chronic medical condition.

METHODS:

A systematic review of articles by using PubMed, PsycINFO, and CINAHL was conducted. Additional studies were identified by searching reference sections of relevant manuscripts. Studies that tested the relationship between medication non-adherence and health care use (ie, hospitalizations, emergency department visits, outpatient visits) or cost in children and adolescents (mean age ≤18 years) who have a chronic medical condition were included. Extraction of articles was completed by using predefined data fields.

RESULTS:

Ten studies met our inclusion criteria. Nine of the 10 studies reviewed (90%) demonstrated a relationship between medication non-adherence and increased health care use. The directionality of this relationship varied depending on the outcome variable of interest.

CONCLUSIONS:

Medication non-adherence is related to increased health care use in children and adolescents who have a chronic medical condition and should be addressed in clinical care. Future studies should include randomized controlled trials examining the impact of adherence promotion efforts on health care use and costs.
Positive Biomechanical Effects of Titanium Oxide for Sandblasting Implant Surface as an Alternative to Aluminium Oxide
Authors: Gehrke Sergio Alexandre , Taschieri Silvio , Del Fabbro Massimo , Coelho Paulo Guilherme
Published: September 2013

The aim of this study was to evaluate the physico-chemical properties and the in vivo host response of a surface sandblasted with particles of titanium oxide (TiO2) followed by acid etching as an alternative to aluminium oxide. Thirty titanium disks manufactured in the same conditions as the implants and 24 conventional cylindrical implants were used. Half of the implants had a machined surface (Gcon) while in the other half; the surface was treated with particles of TiO2 followed by acid etching (Gexp). Surface characterization was assessed by scanning electron microscope (SEM), energy dispersive X-ray spectrometry (EDS), profilometry, and wettability. For the in vivo test, 12 implants of each group were implanted in the tibia of 6 rabbits, and were reverse torque tested after periods of 30 or 60 days after implantation. Following torque, SEM was utilized to assess residual bone-implant contact. The surface characterization by SEM showed a very homogeneous surface with uniform irregularities for Gexp and a small amount of residues of the blasting procedure, while Gcon presented a surface with minimal irregularities from the machining tools. Wettability test showed decreased contact angle for the Gcon relative to the Gexp. The Gexp removal torque at 30 and 60 days was 28.7%, and 33.2% higher relative to the Gcon, respectively. Blasting the surface with particles of TiO2 represents an adequate option for the surface treatment of dental implants, with minimal risk of contamination by the residual debris from the blasting procedure.
Modeling the impacts of life‐history traits, canopy gaps, and establishment location on woodland shrub invasions
Authors: Iannone Basil V. , Zellner Moira L. , Wise David H.
Published: September 2013

We used an individual‐based model to identify how localized patterns of woodland invasions by exotic shrubs are likely influenced by (1) observed variation in age at first reproduction and fecundity, (2) hypothesized effects of canopy gaps on these life‐history traits and dispersal, and (3) initial establishment location. Rates of spread accelerated nearly twofold as age at first reproduction decreased from eight to three years or fecundity increased from 3 to 20 offspring per year, illustrating the need to better understand the factors that influence these life‐history traits. Canopy gaps facilitated spread by influencing these life‐history traits, but not through their effects on dispersal. Invasions starting at the woodland center spread more rapidly than do those starting along the woodland edge. These findings suggest that managers should not only prioritize the removal of shrubs that reproduce the earliest or produce the most offspring, but they should also focus on the invasions in woodlands with high canopy openness and/or that are located in woodland interiors. Investigated factors also affected other invasion characteristics, often in surprising ways. For example, those changes in age at first reproduction and fecundity that increased the rate of spread produced nonparallel patterns of change in the proportions of invasion reproducing, whether or not invasions exhibited clumped or scattered spatial arrangements, and invasional lag. Additionally, canopy gaps influenced these characteristics by increasing fecundity, but not by decreasing age at first reproduction or altering dispersal, suggesting that canopy gaps affect local patterns of exotic‐shrub invasions primarily through their positive effects on fruit production.
Comparison of the Proportion of Non‐Classic (CD14+CD16+) Monocytes/Macrophages in Peripheral Blood and Gingiva of Healthy Individuals and Patients With Chronic Periodontitis
Authors: Jagannathan Raghunathan , Lavu Vamsi , Rao Suresh Ranga
Published: September 2013

Background: Monocyte subsets with low CD14 expression that coexpress CD16 (CD14+CD16+) are called non‐classic or hyperinflammatory monocytes. Previous studies have reported an increase in the percentage of CD14+CD16+ monocytes in the peripheral blood of patients with chronic periodontitis (CP). To our knowledge, there are no reports demonstrating the presence of CD14+CD16+ monocyte–derived macrophages (MDMs) in the gingival tissue. The objective of this study is to identify the proportion of non‐classic (CD14+CD16+) monocytes/macrophages in peripheral blood and gingiva of healthy individuals and patients with CP.

Methods: A total of 60 individuals (n = 30 per group) were recruited for the study. Group 1 included 30 individuals with healthy gingiva, and group 2 included 30 patients with CP. Direct immunofluorescent staining was done in 200 μL whole‐blood and single‐cell suspensions obtained from gingival tissue, with fluorochrome‐conjugated monoclonal antibodies against CD14, CD16, and human leukocyte antigen‐DR (HLA‐DR), and subjected to flow cytometric analysis.

Results: The mean percentage of CD14+CD16+ monocytes in the peripheral blood of healthy individuals was 9.10% ± 1.39%, and for patients with CP it was 14.18% ± 2.69% (P <0.05). The mean percentage of CD14+CD16+ MDMs in the gingival tissue of healthy individuals was found to be 0.93% ± 0.33%, whereas in patients with CP, it was 1.92% ± 0.78% (P <0.01). Non‐classic monocytes/macrophages showed a high median fluorescent intensity for HLA‐DR (DR++).

Conclusion: This study demonstrates an increased proportion of CD14+CD16+HLA‐DR++ monocytes/macrophages in the peripheral blood and gingiva of patients with CP.
Population‐Based 5‐Year Follow‐Up Study in Taiwan of Osteoporosis and Risk of Periodontitis
Authors: Chang Wei‐Pin , Chang Wei‐Chiao , Wu Mei‐Shin , Pai Jei‐Tsung , Guo Yuh‐Cherng , Chen Ku‐Chung , Liu Mu‐En , Chiu Wen‐Ta , Hung Kuo‐Sheng
Published: September 2013

Background: Osteoporosis and periodontitis are both considered global health issues that threaten postmenopausal women and the older population. However, the correlation between osteoporosis and periodontitis is still unclear.

Methods: Using a nationwide Taiwanese population‐based database, data from patients with osteoporosis (2003 to 2005; n = 2,527) and 7,575 individuals who were matched to each patient by age and sex were analyzed. All participants were tracked for 5 years from the date of enrollment to observe the percentage of patients who developed periodontitis. Cox proportional hazard regressions were performed to evaluate 5‐year periodontitis‐free survival rates.

Results: Among the total sample, 3,060 individuals were diagnosed with periodontitis during the 5‐year follow‐up period: 792 in the study cohort and 2,268 in the comparison cohort. The adjusted hazard ratio for periodontitis in patients with osteoporosis compared with individuals without osteoporosis during the 5‐year follow‐up was 1.14 (95% confidence interval = 1.05 to 1.24, P <0.01).

Conclusion: This population‐based study indicated that patients with osteoporosis may have an increased risk of periodontitis.
Platelet‐Rich Plasma, Low‐Level Laser Therapy, or Their Combination Promotes Periodontal Regeneration in Fenestration Defects: A Preliminary In Vivo Study
Authors: Nagata Maria J.H. , de Campos Natália , Messora Michel R. , Pola Natália M. , Santinoni Carolina S. , Bomfim Suely R.M. , Fucini Stephen E. , Ervolino Edilson , de Almeida Juliano M. , Theodoro Letícia H. , Garcia Valdir G.
Published: September 2013

Background: This study histomorphometrically analyzes the influence of platelet‐rich plasma (PRP), low‐level laser therapy (LLLT), or their combination on the healing of periodontal fenestration defects (PFDs) in rats.

Methods: PFDs were surgically created in the mandibles of 80 rats. The animals were randomly divided into four groups: 1) C (control) and 2) PRP, defects were filled with blood clot or PRP, respectively; 3) LLLT and 4) PRP/LLLT, defects received laser irradiation, were filled with blood clot or PRP, respectively, and then irradiated again. Animals were euthanized at either 10 or 30 days post‐surgery. Percentage of new bone (NB), density of newly formed bone (DNB), new cementum (NC), and extension of remaining defect (ERD) were histomorphometrically evaluated. Data were statistically analyzed (analysis of variance; Tukey test, P <0.05).

Results: At 10 days, group PRP presented ERD significantly lower than group C. At 30 days, group PRP presented NB and DNB significantly greater than group C. Groups LLLT, PRP, and PRP/LLLT showed significant NC formation at 30 days, with collagen fibers inserted obliquely or perpendicularly to the root surface. NC formation was not observed in any group C specimen.

Conclusions: LLLT, PRP, or their combination all promoted NC formation with a functional periodontal ligament. The combination PRP/LLLT did not show additional positive effects compared to the use of either therapy alone.
Case History: Clay Free Invert Fluid in Norwegian High-Temperature Well Provides Consistent Low ECD Profile
Authors: Rødsjø Mads , Akutsu Erik , Morris Steven , Mikalsen Renate
Published: September 2013

Historically, invert emulsion drilling fluids (IEFs) require organophilic clays to provide viscosity and suspension characteristics. Whilst effective, these chemicals are prone to stratification in certain conditions, slow chemical reaction times, high pressure spikes, and high equivalent circulating densities (ECDs) attributed to the solids contribution and inherent chemistry of the fluid.

To help reduce such adverse effects, clay based chemicals used in IEFs can be replaced with highly sophisticated polymer viscosifiers, filtration agents, and emulsifiers, which provide a strong, stable emulsion, even with low-oil/water ratio (OWR) IEFs.

Legislation governing the energy industry’s use of chemicals in Norway prohibits use of certain products that are otherwise globally used in drilling fluids. To address such restrictions, extensive research and development has resulted in availability of environmentally acceptable chemicals that produce the unique rheological and suspension characteristics inherent to clay-free IEF systems.

This paper describes the first application of clay-free IEFs in the Norwegian continental shelf (NCS) with an emphasis on an impressively low ECD contribution far more consistent than previously recorded in comparable wells. Further, a treatment was developed to allow the IEFs to be used to drill into a section exhibiting temperatures greater than 160°C. Chemical consumption was substantially lower compared to previous wells using traditional IEF systems, thus reducing shipping requirements.

Before planning the subject well, the environmentally acceptable chemicals intended for use were approved by governing bodies. Consequently, a vertical exploration prospect was selected as the initial well to be drilled using a clay-free IEF. This well was comparable to a previously drilled high pressure/high-temperature HP/HT well, allowing direct comparison of several of the metrics.
The Use of Multi Rotor Remotely Opearated Aerial Vehicles (Roavs) as a Method of Close Visual Inspection (CVI) of Live and Difficult to Access Assets on Offshore Platforms
Authors: Buchan Philip , Connolly Malcolm
Published: September 2013

There is a continual requirement to carry out close visual inspections of plant and equipment on offshore installations for ongoing maintenance. Accessing structures at height or live systems on a process plant poses a number of challenges. ‘Traditional’ methods-of-access to carry out inspection of high or difficult to reach parts of an installation involve using rope access techniques, scaffolding or even full-size helicopters. Rope access inspection can be time-consuming and although it has an excellent safety record it is still potentially dangerous as it involves personnel working at height which is statistically the single biggest cause of workplace fatalities accounting for 25% (5). Scaffolding as an access method for inspection can be expensive, time-consuming and also involves a significant amount of working at height or manual handling operations. While full-size helicopter inspection can mean that many parts of a rig are simply uninspectable, for example the underdeck of a platform. These inspections can also put offshore platforms at a huge commercial disadvantage as assets such as flares need to be shutoff or drilling derricks require drilling activities to stop before the inspection can be completed.

A new method of inspecting live and difficult to access assets has now been developed that allows certain inspection tasks to be performed quicker, safer and more cost effectively than traditional methods. Similar to underwater Remote Operated Vehicles (ROVs), it involves allying engineering expertise to the use of Remotely Operated Aerial Vehicles (ROAVs) for topside and above the waterline inspection. These miniature flying vehicles use HD video, HD still and thermal cameras to provide detailed images for inspection purposes. ROAVs are operated by highly trained pilots in combination with qualified engineers and plant inspectors to create authoritative technical reports and analysis. Offshore operators now have another method available to them to gather information and understand the condition of their assets without shutting down operations allowing informed decision making.

The use of ROAVs for the visual and thermal inspection of onshore structures in refineries and chemical plants has become an established technique over the last 4 years. This technique is starting to become adopted as best practice by some operators for visual inspection of certain assets such as flare stacks. The potential of the technique of using ROAV for certain inspection tasks is now being recognised in an offshore context with the first use of this technology in the North Sea in January 2012.

This paper provides an introduction to the concept of inspection using ROAVs, overview of the technology, benefits of the technique, limitations of its application, safety considerations, case studies and a look to the future for the industry.
Offshore Horizontal Well Fracturing: Operational Optimisation in the Southern North Sea
Authors: Langford Marc , Holland Brian , Green Christopher A. , Bocaneala Bogdan , Norris Mark
Published: September 2013

Recently, there has been an increased interest in optimising horizontal multifrac completion technologies used to complete unconventional US onshore wells. The developing technologies and techniques are increasingly being used for offshore applications and have found widespread use in horizontal wells in areas such as the southern North Sea. This case history describes the application of two complementary technologies which have enabled the placement of 1.4 million pounds of proppant in four treatments within 4 consecutive days. Prior to this similar offshore completion operations have typically taken 12 to 25 days.

Historically, cemented liners and "plug-and-perf" completions have been used for horizontal fracturing in the southern North Sea. Such operations often involve extensive coiled tubing interventions between fracturing stages. This introduces unnecessary technical and associated operational risks due to the extended, long horizontal well architectures that are often used. An openhole, ball-activated multi-stage system, recently introduced into the North Sea, was applied in tandem with the application of a new environmentally-compliant seawater fracturing fluid. The use of the seawater-based system allowed sufficient fluid volume to be loaded and pumped for the placement of four hydraulic fracturing treatments on consecutive days, without the need for the vessel to disconnect and sail back to port to reload fresh water.

As a result of this dual development and correct application of the completion technologies, the requirement for coiled-tubing interventions between stages was eliminated, saving both vessel and rig time. Ultimately, such savings result in faster turnaround times for wells to be placed on production, thereby improving overall well economics. Following the success of the application of this technology the operator is actively pursuing similar new complimentary technologies. Such operational improvements will not only enhance well economics, but possibly define future North Sea fracturing operations.
Minimising Underwater Noise Impact from Offshore Activities
Authors: Fulton Natalia , Kuo Chengi
Published: September 2013

This paper is concerned with human activities relating to offshore exploration and exploitation that have adverse effects on marine animals. It addresses noise pollution caused by tasks such as piling, drilling, exploration etc. Loud noise produced during offshore operations can seriously affect one of the main senses – hearing. The paper examines sources of noise and methods of mitigating it to tolerable levels. Research is focused on the use of bubble curtains for noise reduction. The main conclusion is that the bubble curtain is a recognised noise reduction/shielding method and its effectiveness is dependent on bubble size and water depth in addition to water temperature, density and salinity.
Low Cycle Fatigue Analysis of Threaded Connectors for Subsea Drilling and Production
Authors: Zhu B. , Steen T. L. , Patterson W. R. , Thomas M. , Balaji Durai , G. Rajesh Kumar
Published: September 2013

Threaded connectors are utilized in a wide range of subsea oil & gas applications, from large diameter conductor casings to smaller diameter risers. As oil & gas drilling and production continues to progress into deeper waters the demand for reliable, cost effective, and high performance connectors will continue to grow. During the development phase of new threaded connectors Finite Element Analysis (FEA) is utilized to evaluate the structural capacity and performance of the connector under a wide range of load scenarios. When tension or bending loads are applied to a threaded connector, the start and end of the thread take significantly more load than the center of the thread. The stress in the thread resulting from this load distribution takes the form of a bathtub and is referred to as a "bathtub curve". Under high cyclic bending and/or tension loading, the start and end of the thread can yield, resulting in a more even load sharing between the entire thread. The magnitude of this re-distribution of load has been analyzed to illustrate its impact on the fatigue performance of threaded connectors.