bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation of Behaviour of an Energy Storage Device During Installation Process in Lake Ontario
Authors: Zaman M. Hasanat , Akinturk Ayhan , McGillis Andrew
Published: September 2018

A model of a compressed air energy storage unit is tested for tow-out and installation in the Ocean, Coastal & River Engineering (OCRE) Portfolio of the National Research Council of Canada (NRC). The proposed prototype accumulator is a cylinder of 36 m in diameter and 12 m in height, which will be installed at the bottom of Lake Ontario at about 60 m water depth. The model of the accumulator with scale 1:21.5 was fabricated at the Design and Fabrication Unit of NRC. Appropriate ballast systems were designed and applied for the tow out, installations and release mechanism tests. The model scale test was conducted to examine the hydrodynamic behavior of the accumulator during tow-out and set down operations. NRC’s Towing Tank and Offshore Engineering Basin test facilities were used for the tasks. In this paper only the installation case of the accumulator is reported and discussed. Relevant numerical simulations are also carried out. Comparisons of the numerical results with the experimental results show good agreement for the compared cases.
The Research and Application of ECA Technology for Large Diameter Thick Wall Subsea Pipeline in a Gas Field in Deep Water of South China Sea
Authors: Hou Jing
Published: September 2018

In order to ensure the integrity of subsea pipeline in the whole design life, it is very important to carry out quality evaluation for the girth welding since severe ocean environment and installation conditions. In this paper, based on the principle of “suitable for use”, the level 2B, British BS7910 standard fracture assessment criterion is adopted. According to the mechanical properties of the pipe joint, welding method and installation load conditions, the Engineering Critical Assessment (ECA) has been carried out for an export subsea pipeline in a gas field in deep water of South China Sea. Larger allowable initial weld flaws can be accepted through ECA evaluation, the acceptable criterion for AUT inspection in the process of pipeline laying is obtained, which effectively reduce the welding repair rate with significant cost saving and improve installation efficiency.
Experimental Study on Hydrodynamics of Hybrid Deep-V Monohull With Different Built-Up Appendages
Authors: Sun Shuzheng , Li Hui , Ong Muk Chen
Published: September 2018

The hydrodynamic characteristics of a hybrid deep-V monohull with different built-up appendages are investigated experimentally in order to improve the resistance and seakeeping performance. Model tests have been carried out to study the hydrodynamic performance between a bare deep-V vessel and a deep-V monohull with different built-up appendage configurations (i.e. a hybrid deep-V monohull). From the model test results, it is found that the existence of the appendages will reduce the amplitude of pitching angle and bow vertical acceleration compared to that of the bare deep-V vessel in heading regular waves. However, the resistances for the hybrid deep-V monohull with built-up appendages are increased 15.6% for Fn = 0.264, and 0.1% for Fn = 0.441 compared to the resistance of the bare deep-V vessel. The model test results of seakeeping performance in irregular waves show that the hybrid deep-V monohull gives a better seakeeping performance than the deep-V vessel. The pitching angle and bow vertical acceleration of the hybrid deep-V monohull containing a built-up appendage are reduced 15.3% and 20.6% compared to the deep-V monohull in irregular waves at Fn = 0.441 in 6th class sea state (H1/3 = 6m).
Experimental Study and Modeling of Heating Effect in Electrical Submersible Pump Operating With Ultra-Heavy Oil
Authors: Biazussi Jorge Luiz , Estrada Cristhian Porcel , Verde William Monte , Bannwart Antonio Carlos , Estevam Valdir , Rocha Paulo S. , Neto Salvador J. A. , Tavares Alexandre
Published: September 2018

A notable trend in the realm of oil production in harsh environments is the increasing use of Electrical Submersible Pump (ESP) systems. ESPs have even been used as an artificial-lift method for extracting high-viscosity oils in deep offshore fields. As a way of reducing workover costs, an ESP system may be installed at the well bottom or on the seabed. A critical factor, however, in deep-water production is the low temperature at the seabed. In fact, these low temperatures constitute the main source for many flow-assurance problems, such as the increase in friction losses due to high viscosity. Oil viscosity impacts pump performance, reducing the head and increasing the shaft power. This study investigates the influence of a temperature increase of ultra-heavy oil on ESP performance and the heating effect through a 10-stage ESP. Using several flow rates, tests are performed at four rotational speeds and with four viscosity levels. At each rotational speed curve, researchers keep constant the inlet temperature and viscosity. The study compares the resulting data with a simple heat model developed to estimate the oil outlet temperature as functions of ESP performance parameters. The experimental data is represented by a one-dimensional model that also simulates a 100-stage ESP. The simulations demonstrate that as the oil heat flows through the pump, the pump’s efficiency increases.
Validation of Adaptive Gaussian Process Regression Model Used for SIF Prediction
Authors: Keprate Arvind , Ratnayake R. M. Chandima , Sankararaman Shankar
Published: September 2018

The main aim of this paper is to perform the validation of the adaptive Gaussian process regression model (AGPRM) developed by the authors for the Stress Intensity Factor (SIF) prediction of a crack propagating in topside piping. For validation purposes, the values of SIF obtained from experiments available in the literature are used. Sixty-six data points (consisting of L, a, c and SIF values obtained by experiments) are used to train the AGPRM, while four independent data sets are used for validation purposes. The experimental validation of the AGPRM also consists of the comparison of the prediction accuracy of AGPRM and Finite Element Method (FEM) relative to the experimentally derived SIF values. Four metrics, namely, Root Mean Square Error (RMSE), Average Absolute Error (AAE), Maximum Absolute Error (MAE), and Coefficient of Determination (R2), are used to compare the accuracy. A case study illustrating the development and experimental validation of the AGPRM is presented. Results indicate that the prediction accuracy of the AGPRM is comparable with and even higher than that of the FEM, provided the training points of the AGPRM are aptly chosen.
Wells Turbine With Variable Blade Profile for Wave Energy Conversion
Authors: Miguel González Celia , Rodríguez Fuertes Ginés , García Díaz Manuel , Pereiras García Bruno , Castro Francisco , Fernández Oro Jesus Manuel
Published: September 2018

It is well known among the researchers involved in the field of turbines for Oscillating Water Column systems (OWC) that the main problem for Wells turbines is the stall, which appears when the main flow incidence angle exceeds certain value and leads to a sharp drop in the efficiency. It also causes problems during the starting, driving the turbine to not reach the designing rotation speed.

Delaying the stall apparition is the key to improve the performance of the Wells turbine. is necessary to delay the flow separation at the trailing edge because it is the reason which leads to the sharp efficiency drop at the stall point.

One of the solutions proposed by researchers in this field is using a variable blade profile instead of the traditional ones, built using constant chord and profile from hub to tip. This work tries to dig deeper in this line by analysing a blade with variable chord and shape among the blade span.

The work has been developed numerically by using commercial software ANSYS FLUENT®. A CFD code was created in order to obtain the performance curve of the turbine proposed to be compared with those assumed as reference, which were taken from the bibliography and also used to validate the numerical model.

The results have shown that an improvement has been achieved. It confirms that using a variable blade profile is a suitable solution to delay the stall apparition.
Research on Trailing Cavity of Underwater Vehicles Based on Potential Flow Theory
Authors: Shi Zeyu , Yao Xiongliang , Zhao Jiaolong , Sun Longquan , Tian Yue
Published: September 2018

In the exceeding water process of underwater vehicles, the existing of trailing cavity will have distinct effects on the hydrodynamic characteristics of vehicles. Recent researches mostly leave gravity effect out of consideration, while the gravity will affect trailing cavity characteristics and then affect the hydrodynamic characteristics of vehicles. In this study, we research the effect of gravity on the trailing cavity of underwater vehicles. Firstly, a complex boundary model which taken partial cavity into consideration is established based on potential flow theory and a program according to this model is written. Because all flow parameter has nothing to do with the radial location, the research problem can be simplified as a two-dimensional problem and studied in polar coordinates. With regularization of the length of the navigation calculation model, infinity to flow velocity and the distance pressure, research domain can be represented by plane in the containing slit. The program is proved to be effective by comparison the results with the data in existing papers. Finally, we calculate the trailing cavity forms of a cone and an underwater vehicle under different cavitation numbers and Froude numbers to study the rules of trailing cavity forms changing with cavitation number and Froude number. Under the same number of Froude, the cavity size of the rear part of vehicle gradually decreases with the increasing cavitation number, and the maximum radius of the cavity equals to the biggest size of the tail radius of the vehicle. Under the same cavitation number bodies, vehicle trailing cavity length gradually increases with the increase of Froude number, but radius of the cavity of the vehicle changed little, the largest radius is equivalent to the tail radius of the vehicle.
Out-of-Plane Bending Moment-Induced Hotspot Stress Evaluation Using Advanced Numerical Technique
Authors: Lee Jae-bin , Koo Weoncheol , Choung Joonmo
Published: September 2018

There have been various studies to predict out-of-plane bending (OPB) moment-induced stresses in mooring chain links. Recently, the BV guideline as one of the deliverables from OPB JIP reported empirical formulas to predict the nominal OPB moment-induced stress with suitable concentration factors (SCFs) so that prediction of the OPB moment-induced hotspot stresses can be available. A non-linear finite element analysis technique has been developed to more accurately estimate the OPB moment-induced hotspot stress. There has been no choice but to apply prescribed rotation to generate the OPB moment in this numerical technique (existing approach). Pointing out some disadvantages in the BV guideline and existing approach, an advanced numerical was proposed to simulate more realistic tension-induced OPB mechanism. In the present paper, basic differences were presented in terms of numerical simulation techniques, nominal OPB moments, and hotspot OPB stresses. In order to show differences of the stress distributions and the hotspot OPB stresses between existing and advanced approaches, a benchmark chain link model was constructed in which the nominal diameter was 107mm. From the comparison of stress distributions in straight parts of the link, significant differences were found between the existing and advanced approaches. The existing approach more developed the compressive stresses due to the prescribed rotation-induced OPB moment than the advanced approach. This also led to more increased hotspot OPB moments.
Probabilistic Response of Composite Plates for Damage Initiation due to Low Velocity Impact
Authors: Patel Shivdayal , Ahmad Suhail
Published: September 2018

The low velocity impact (LVI) result of laminated targets is an imperative study to evaluate its failure for applications to inconsequential structures. The work has extensive applications to off shore and naval industry. Safety and reliability assessment as per the international standards is one of the basic objectives of the study. LVI on composite plates is performed taking the material parameters and loading condition as random variables. Graphite fiber reinforced laminated plates are vulnerable to damage due to impact by foreign objects and in plane loading. In order to evaluate the safe load carrying capacity and the reliability under impact, dynamic analysis of composite plate subjected to LVI is carried out. Probabilistic finite element method (PFEM) is performed to determine the stochastic response. During impact, the in-plane damage modes such as matrix cracking, fiber failure and shear cracking are modeled using a failure criterion. The out of plane de-lamination is modeled using cohesive surfaces. The randomness associated with the system properties due to the inherent scatter in the geometric and material properties and input loads are modeled in a stochastic fashion. Random parameters represent various characteristics appearing in the performance function. The stochastic response and reliability forecast of the system is determined by Gaussian processes response surface method (GPRSM) and validity of method for the present problem is establish using Monte Carlo simulation (MCS) procedure. The safety level qualification is achieved in terms of reliability level targeted.
Vertical Motion Response of a Submerged Body Induced by Interfacial Solitary Waves
Authors: Gou Y. , Wang R. , Teng B.
Published: September 2018

A simple time-domain numerical model is established to consider the interfacial solitary wave actions on submerged body and the body’s vertical motion. The vertical drag and inertial force on the moving submerged body induced by interfacial solitary wave is computed by Morison equation. The motion equation is solved by the fourth-order Runge-Kutta method. A horizontal submerged slender circular cylinder beneath the interface with forward speed is considered in this paper. The calculations show that when the depression internal solitary wave keeps close to the submerged body, the vertical forces on the body, including interfacial solitary wave force and buoyance, change greatly and the body moves downward with a great displacement in a short time. The main reason which results in the great vertical motion is the decrease of buoyance when submerged body moves into the less density water layer. It can be concluded that the great threat to submarine’s navigation is the density variation caused by interfacial solitary wave. The parameter effect of forward speed of the submerged body is also investigated.
Reliable Estimation of Low-Frequency Viscous Damping for a Turret-Moored FLNG in Current
Authors: Huang Z. , Ryu S. , Lee D. , Hughes C. S.
Published: September 2018

For a turret-moored Floating Liquefied Natural Gas Plant (FLNG), it is important to use confidently derived low frequency viscous damping coefficients in the prediction of its motions and mooring loads in wind, wave and current conditions. In this paper we present our recent experimental work on the low frequency sway and yaw viscous damping in calm water and in current. In general, damping force is a relatively small portion of the total hydrodynamic force on an oscillatory model. In a previous ExxonMobil damping test in calm water (Huang et al., 2010), i.e. without current and wave, a deeply submerged double-body model was forced to oscillate to avoid surface wave contamination. An inertia compensation system was also designed to cancel the inertia force and the restoring force during oscillations, then the measured force was mainly damping force. Because of the schedule constraints of the present study, it was not possible to perform the submerged oscillation test. Instead, a forced oscillation test in water surface was performed based on KC-number and β-number. In order to obtain reliable damping coefficients, we had to carefully design the test conditions, i.e. current speeds, oscillation amplitudes and frequencies so that an adequate portion of damping force within the total force could be achieved with no significant surface waves that could contaminate the damping results being generated by the oscillating model. Good damping results were obtained. To check the acceptance of the test method based on Froude scaling, a limited number of tests were performed in which the oscillation amplitudes and frequencies were scaled down based on the Froude scaling. Magnitudes of the measured force and moment are significantly low. The time series of the measurements have drifting and significant noise. We could not confidently determine viscous damping results from the measurements.
Evaluation of Aluminum-Coated Flexible Pipe Armour Wires Exposed to a Sour Environment
Authors: Bertoncello João C. B. , Tagliari Mariana R. , Coser Tiago B. , Kerpen Felippe S. , Santana Luciano M. , Paes Marcelo T. P. , Kwietniewski Carlos E. F.
Published: September 2018

In general, tensile armour wires of flexible pipes that are designed for sour applications have their strength limited to 850 MPa due to the possibility of embrittlement phenomena to occur. A Thermally Sprayed Aluminum (TSA) coating 250 μm thick was applied to high strength steels with UTS of 1470 MPa and YS of 1280 MPa. Three specimens conditions were evaluated: full coating, no coating and coating with a designed defect. The load was applied using a four point bending fixture, maintaining a constant stress of 90% of material’s yield strength. All tests were performed in accordance with recommendations of NACE TM 0177 method B. The test solution was distilled water with NaCl 5.0% saturated with a gas mixture of 10,000 ppm of H2S in balance with CO2 during 720 hours. It was observed that samples without coating were more susceptible to the effect of the environment presenting higher degradation and failure. The fractures presented typical characteristic of the Sulfide Stress Corrosion Cracking (SSCC). Furthermore, it was detected parallel cracks to the surface of the wires indicating the embrittlement phenomenon of Hydrogen-Induced Cracking (HIC). On the other hand, coated samples with and without defects did not fail during the 720 hours of testing. A posterior non-destructive testing and a metallographic analysis did not identify the presence of cracks. These results were attributed to the physical barrier of the aluminum coating and the cathodic protection generated by the preferential aluminum corrosion. This preliminary study shows that TSA coatings can be a good alternative to increase the corrosion resistance of armour wires in sour environments allowing the application of higher strength steels.
Stabilized Water-Cut in Carbonate Naturally-Fractured Reservoirs With Bottom Water With an Implication in Well Spacing Design for Recovery Optimization
Authors: Prasun Samir , Wojtanowicz A. K.
Published: September 2018

Maximum stabilized water-cut (WC), also known as ultimate water-cut in a reservoir with bottom-water coning, provides important information to decide if reservoir development is economical. To date, theory and determination of stabilized water-cut consider only single-permeability systems so there is a need to extend this concept to Naturally Fractured Reservoirs (NFRs) in carbonate rocks — known for severe bottom water invasion. This work provides insight of the water coning mechanism in NFR and proposes an analytical method for computing stabilized water-cut and relating to well-spacing design.

Simulated experiments on a variety of bottom-water hydrophobic NFRs have been designed, conducted, and analyzed using dual-porosity/dual-permeability (DPDP) commercial software. They show a pattern of water cut development in NFR comprising the early water breakthrough and very rapid increase followed by water cut-stabilization stage, and the final stage with progressive water-cut. The initial steply increase of water-cut corresponds to water invading the fractures. The stabilized WC production stage occurs when oil is displaced at a constant rate from matrix to the water-producing fractures. During this stage water invades matrix at small values of capillary forces so they do not oppose water invasion. In contrast, during the final stage (with progressing water cut) the capillary forces grow significantly so they effectively oppose water invasion resulting in progressive water cut.

A simple analytical model explains the constant rate of oil displacement by considering the driving effect of gravity and viscous forces at a very small value of capillary pressure. The constant oil displacement effect is confirmed with a designed series of simulation experiments for a variety of bottom-water NFRs. Statistical analysis of the results correlates the duration of the stabilized WC stage with production rate and well-spacing and provides the basis for optimizing the recovery. Results show that stabilized water-cut stage does not significantly contribute to recovery, so the stage needs to be avoided. Proposed is a new method for finding the optimum well spacing that eliminates the stabilized WC stage while maximizing recovery. The method is demonstrated for the base-case NFR.
Efficacious Analogs of the Lantibiotic Mutacin 1140 against a Systemic Methicillin-Resistant Staphylococcus aureus Infection
Authors: Geng Mengxin , Ravichandran Akshaya , Escano Jerome , Smith Leif
Published: September 2018

Mutacin 1140, a member of the epidermin family of type AI lantibiotics, has a broad spectrum of activity against Gram-positive bacteria. It blocks cell wall synthesis by binding to lipid II.
Draft Genome Sequences of Pseudomonas MWU13-2625 and MWU12-2115, Isolated from a Wild Cranberry Bog at the Cape Cod National Seashore
Authors: Ebadzadsahrai Ghazal , Thomson Jonathon , Soby Scott
Published: September 2018

Two highly similar
Pseudomonas
sp. genome sequences from wetland bog soil isolates with draft genomes of ~6.3 Mbp are reported.
Complete Genome Sequence of a Wild-Type Isolate of Caulobacter vibrioides Strain CB1
Authors: Scott Derrick C. , Wilson Kiesha , Ross Keshawn , Ingram Damyen , Lewter Tajah , Herring Jasmine , Duncan David , Aikins Anthea , Ely Bert
Published: September 2018

The complete genome sequence of
Caulobacter vibrioides
strain CB1 consists of a chromosome of 4,137,285 bp, with a GC content of 67.2% and 3,990 coding DNA sequences. This strain contains the typical genome rearrangement that is characteristic of the
Caulobacter
strains that are currently sequenced.
Gossypiboma: a ghastly find
Authors: de Gea Rico Aitor , Krishna Priya , Devlin Hannah Louise , Rohatgi Ashish
Published: September 2018

A gossypiboma is a mass within a patient’s body comprising a cotton matrix surrounded by a foreign body granuloma. We describe an unusual presentation of a gossypiboma presenting in a 32-year-old man with acute epigastric pain and haematemesis. His surgical history revealed an emergency laparotomy following a road traffic accident 16 years ago. Initial gastroscopy showed extrinsic stomach compression. An abdominal ultrasound scan followed by a CT scan evidenced a large, well-defined, predominantly cystic mass with some solid areas occupying the left hypochondrium. Conservative management with insertion of a percutaneous drain proved to be inefficient. A laparotomy was performed; intraoperatively, the cyst was found to be ruptured and within it, a large surgical gauze was found. This was removed but required a distal pancreatectomy and gastrectomy for complete excision. He was discharged on day 74 of admission with outpatient follow-up.
Association between physician
US News & World Report
medical school ranking and patient outcomes and costs of care: observational study
Authors: Tsugawa Yusuke , Blumenthal Daniel M , Jha Ashish K , Orav E John , Jena Anupam B
Published: September 2018

Objective

To investigate whether the
US News & World Report
(USNWR) ranking of the medical school a physician attended is associated with patient outcomes and healthcare spending.

Design

Observational study.

Setting

Medicare, 2011-15.

Participants

20% random sample of Medicare fee-for-service beneficiaries aged 65 years or older (n=996 212), who were admitted as an emergency to hospital with a medical condition and treated by general internists.

Main outcome measures

Association between the USNWR ranking of the medical school a physician attended and the physician’s patient outcomes (30 day mortality and 30 day readmission rates) and Medicare Part B spending, adjusted for patient and physician characteristics and hospital fixed effects (which effectively compared physicians practicing within the same hospital). A sensitivity analysis employed a natural experiment by focusing on patients treated by hospitalists, because patients are plausibly randomly assigned to hospitalists based on their specific work schedules. Alternative rankings of medical schools based on social mission score or National Institute of Health (NIH) funding were also investigated.

Results

996 212 admissions treated by 30 322 physicians were examined for the analysis of mortality. When using USNWR primary care rankings, physicians who graduated from higher ranked schools had slightly lower 30 day readmission rates (adjusted rate 15.7% for top 10 schools
v
16.1% for schools ranked ≥50; adjusted risk difference 0.4%, 95% confidence interval 0.1% to 0.8%; P for trend=0.005) and lower spending (adjusted Part B spending $1029 (£790; €881)
v
$1066; adjusted difference $36, 95% confidence interval $20 to $52; P for trend <0.001) compared with graduates of lower ranked schools, but no difference in 30 day mortality. When using USNWR research rankings, physicians graduating from higher ranked schools had slightly lower healthcare spending than graduates from lower ranked schools, but no differences in patient mortality or readmissions. A sensitivity analysis restricted to patients treated by hospitalists yielded similar findings. Little or no relation was found between alternative rankings (based on social mission score or NIH funding) and patient outcomes or costs of care.

Conclusions

Overall, little or no relation was found between the USNWR ranking of the medical school from which a physician graduated and subsequent patient mortality or readmission rates. Physicians who graduated from highly ranked medical schools had slightly lower spending than graduates of lower ranked schools.
Perioperative laryngospasm management in paediatrics: a high-fidelity simulation study
Authors: Michelet Daphné , Truchot Jennifer , Piot Marie-Aude , Drummond David , Ceccaldi Pierre-François , Plaisance Patrick , Tesnière Antoine , Dahmani Souhayl
Published: September 2018

Aim

Paediatric anaesthesia is a very specialised domain lacking training during the traditional curriculum. The laryngospasm is a stressful and life-threatening event that requires immediate action. The main objective of this study was to assess the effect of knowledge of a simple algorithm on the management of laryngospasm by trainee anaesthetists and nurse anaesthetists during a high-fidelity simulation session.

Method

Residents in paediatric anaesthesia and training nurse anaesthetists with similar curriculum were randomly allocated to undergo a simulation session of laryngospasm with the help of a simple algorithm administered to them 5 min before the simulation session (group A) or as taught in their curriculum (group C). The primary endpoint was the assessment score of laryngospasm management using 10 technical items (validated in experienced paediatric anaesthetists). Secondary endpoints were: the non-technical skills using the Anaesthetists' Non-Technical Skills (ANTS) score and timing of critical management steps. The correlation between the technical and non-technical scores was also studied. Data are expressed as median (range).

Results

72 participants (18 teams in each group) were included in this study. There was a statistically significant difference between group A and C on the primary endpoint: 8.5 (2–10) vs 5 (2–8), respectively (p<0.0001). There was also a significant difference between the two groups for the ANTS score 12 (7–16) vs 8 (6–12), respectively (p<0.0001). No difference in timing of management was observed. Finally, there was a strong correlation between the technical skills and all the non-technical skills categories in the A group.

Conclusion

A simple algorithm improved the technical and non-technical skills of students during the management of a simulated laryngospasm.
Long-term quality-adjusted survival following therapeutic bronchoscopy for malignant central airway obstruction
Authors: Ong Philip , Grosu Horiana B , Debiane Labib , Casal Roberto F , Eapen George A , Jimenez Carlos A , Noor Laila , Ost David E
Published: September 2018

Background

While therapeutic bronchoscopy has been used to treat malignant central (CAO) airway obstruction for >25 years, there are no studies quantifying the impact of therapeutic bronchoscopy on long-term quality-adjusted survival.

Methods

We conducted a prospective observational study of consecutive patients undergoing therapeutic bronchoscopy for CAO. Patients had follow-up at 1 week and monthly thereafter until death. Outcomes included technical success (ie, relief of anatomic obstruction), dyspnoea, health-related quality of life (HRQOL) and quality-adjusted survival.

Results

Therapeutic bronchoscopy was performed on 102 patients with malignant CAO. Partial or complete technical success was achieved in 90% of patients. At 7 days postbronchoscopy, dyspnoea improved (mean ∆Borg-day-7=−1.8, 95% CI −2.2 to −1.3, p<0.0001) and HRQOL improved (median prebronchoscopy 0.618 utiles, 25%–75% IQR 0.569 to 0.699, mean ∆utility-day-7+0.047 utiles, 95% CI +0.023 to 0.071, p=0.0002). Improvements in dyspnoea and HRQOL were maintained long-term. Compared with the prebronchoscopy baseline, HRQOL per day of life postbronchoscopy improved (mean ∆utility-long-term+0.036 utiles, 95% CI +0.014 to 0.057, p=0.002). Median quality-adjusted survival was 109 quality-adjusted life-days (QALDs) (95% CI 74 to 201 QALDs). Factors associated with longer quality-adjusted survival included better functional status, treatment-naïve tumour, endobronchial disease, less dyspnoea, shorter time from diagnosis to bronchoscopy, absence of cardiac disease, bronchoscopic dilation and receiving chemotherapy.

Conclusions

Therapeutic bronchoscopy improves HRQOL as compared with baseline, resulting in approximately a 5.8% improvement in HRQOL per day of life. The risk-benefit profile in these carefully selected patients was very favourable.

Trial registration number

Results; NCT03326570.
Influence of streambank fencing on vegetation and soil of the Mixed prairie component in a complex corridor pasture
Authors: Miller J.J. , Curtis T. , Willms W.D. , Chanasyk D.S.
Published: September 2018

A 5 yr (2011–2015) field study was conducted to test the hypothesis that streambank fencing had a significant effect on selected vegetation and soil properties of the Mixed prairie component of a complex corridor pasture. The grazing treatments [ungrazed (UG) – periodic grazing (PG)] inside the corridor pasture were 11 yr (2001–2012) of cattle exclusion (UG), followed by 3 yr (2013–2015) of periodic grazing (PG) when the riparian soil was dry. A control treatment outside the fencing was continuous grazing (CG). Selected vegetation and soil properties were measured over the growing season at 10 paired locations in each treatment (nonreplicated) pasture over 5 yr (2011–2015), and rangeland health was measured in 2011. The UG–PG treatment significantly (P ≤ 0.10) increased the total biomass by 2- to 5-fold in all 5 yr compared with CG treatment and improved the rangeland health score of the UG phase of the UG–PG (63%) treatment compared with the CG treatment (50%) in 2011. It also significantly reduced surface soil temperature by 2.2–5.2 °C, significantly increased volumetric water content of the surface soil by 7%–10% in 3 of 5 yr, and significantly increased surface soil CO2 efflux (instantaneous) by 17%–60% in all 5 yr. Overall, the UG–PG treatment improved rangeland health, increased total biomass, soil water, and soil CO2 efflux of the Mixed prairie, but decreased soil temperature compared with the CG treatment. Excessive dead biomass, greater fire risk, and an increase in noxious weeds caused by cattle exclusion suggested that periodic grazing may be the preferred option.
Nonperturbative one-loop effective action for QED with Yukawa couplings
Authors: Jacobson Theodore N. , ter Veldhuis Tonnis
Published: September 2018

We derive the one-loop effective action for scalar, pseudoscalar, and electromagnetic fields coupled to a Dirac fermion in an extension of QED with Yukawa couplings. Using the Schwinger proper-time formalism and zeta-function regularization, we calculate the full nonperturbative effective action to one loop in the constant background field approximation. Our result is nonperturbative in the external fields, and goes beyond existing results in the literature which treat only the first nontrivial order involving the pseudoscalar. The result has an even and odd part, which are related to the modulus and phase of the fermion functional determinant. The even contribution to the effective action involves the modulus of the effective Yukawa couplings and is invariant under global chiral transformations while the odd contribution is proportional to the angle between the scalar and pseudoscalar couplings. In different limits the effective action reduces either to the Euler–Heisenberg effective action or the Coleman–Weinberg potential. We also comment on the relationship between the odd part of the effective action and the chiral anomaly in QED.
Research Notes: Binary Test-Suites Using Covering Arrays
Authors: Torres-Jimenez Jose , Avila-George Himer , Parra-González Ezra Federico
Published: September 2018

Software testing is an essential activity to ensure the quality of software systems. Combinatorial testing is a method that facilitates the software testing process; it is based on an empirical evidence where almost all faults in a software component are due to the interaction of very few parameters. The test generation problem for combinatorial testing can be represented as the construction of a matrix that has certain properties; typically this matrix is a covering array. Covering arrays have a small number of tests, in comparison with an exhaustive approach, and provide a level of interaction coverage among the parameters involved. This paper presents a repository that contains binary covering arrays involving many levels of interaction. Also, it discusses the importance of covering array repositories in the construction of better covering arrays. In most of the cases, the size of the covering arrays included in the repository reported here are the best upper bounds known, moreover, the files containing the matrices of these covering arrays are available to be downloaded. The final purpose of our Binary Covering Arrays Repository (BCAR) is to provide software testing practitioners the best-known binary test-suites.
Quadratic-monomial generated domains from mixed signed, directed graphs
Authors: Burr Michael A. , Lipman Drew J.
Published: September 2018

Determining whether an arbitrary subring [Formula: see text] of [Formula: see text] is a normal or Cohen-Macaulay domain is, in general, a nontrivial problem, even in the special case of a monomial generated domain. We provide a complete characterization of the normality, normalizations, and Serre’s [Formula: see text] condition for quadratic-monomial generated domains. For a quadratic-monomial generated domain [Formula: see text], we develop a combinatorial structure that assigns, to each quadratic monomial of the ring, an edge in a mixed signed, directed graph [Formula: see text], i.e. a graph with signed edges and directed edges. We classify the normality and the normalizations of such rings in terms of a generalization of the combinatorial odd cycle condition on [Formula: see text]. We also generalize and simplify a combinatorial classification of Serre’s [Formula: see text] condition for such rings and construct non-Cohen–Macaulay rings.
PRICING SOVEREIGN CONTINGENT CONVERTIBLE DEBT
Authors: CONSIGLIO ANDREA , TUMMINELLO MICHELE , ZENIOS STAVROS A.
Published: September 2018

We develop a pricing model for Sovereign Contingent Convertible bonds (S-CoCo) with payment standstills triggered by a sovereign’s Credit Default Swap (CDS) spread. We model CDS spread regime switching, which is prevalent during crises, as a hidden Markov process, coupled with a mean-reverting stochastic process of spread levels under fixed regimes, in order to obtain S-CoCo prices through simulation. The paper uses the pricing model in a Longstaff–Schwartz American option pricing framework to compute future state contingent S-CoCo prices for risk management. Dual trigger pricing is also discussed using the idiosyncratic CDS spread for the sovereign debt together with a broad market index. Numerical results are reported using S-CoCo designs for Greece, Italy and Germany with both the pricing and contingent pricing models.
Integration by parts formula for SPDEs with multiplicative noise and its applications
Authors: Huang Xing , Liu Li-Xia , Zhang Shao-Qin
Published: September 2018

By using the Malliavin calculus, the Driver-type integration by parts formula is established for the semigroup associated to SPDEs with Multiplicative Noise. Moreover, estimates on the logarithmic derivative of the transition probability measure are obtained. A concrete example to describe evolution of spin systems on discrete lattices is given to illustrate our main result.
Vertically Aligned WO3–CuO Core–Shell Nanorod Arrays for Ultrasensitive NH3 Detection
Authors: yan Wenjun , Hu Ming
Published: September 2018

Vertically aligned WO3–CuO core–shell nanorod arrays for NH3 sensing are prepared. The sensor is fabricated by preparing WO3–CuO nanorod arrays directly on silicon wafer with interdigital Pt electrodes. The WO3–CuO nanorod arrays are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The sensor based on the vertically aligned WO3–CuO nanorod arrays exhibits ultrasensitive NH3 detection, indicating [Formula: see text]-type behavior. The optimum sensing temperature is found to be about 150[Formula: see text]C. Both response and recovery time to NH3 ranging from 50[Formula: see text]ppm to 500[Formula: see text]ppm are around 10–15[Formula: see text]s. A possible NH3 sensing mechanism of the vertically aligned hybrid nanorod arrays is proposed.
Certain inequalities for the Casorati curvatures of submanifolds of generalized (k,μ)-space-forms
Authors: Hui Shyamal Kumar , Mandal Pradip , Alkhaldi Ali H. , Pal Tanumoy
Published: September 2018

The paper deals with the study of Casorati curvature of submanifolds of generalized [Formula: see text]-space-form with respect to Levi-Civita connection as well as semisymmetric metric connection and derived two optimal inequalities between scalar curvature and Casorati curvature of such space forms. The equality cases are also considered.
Multi-Objective Optimization of Energy Consumption of GUIs in Android Apps
Authors: Linares-Vásquez Mario , Bavota Gabriele , Bernal-Cárdenas Carlos , Penta Massimiliano Di , Oliveto Rocco , Poshyvanyk Denys
Published: September 2018

The number of mobile devices sold worldwide has exponentially increased in recent years, surpassing that of personal computers in 2011. Such devices daily download and run millions of apps that take advantage of modern hardware features (e.g., multi-core processors, large Organic Light-Emitting Diode—OLED—screens, etc.) to offer exciting user experiences. Clearly, there is a cost to pay in terms of energy consumption and, in particular, of reduced battery life. This has pushed researchers to investigate how to reduce the energy consumption of apps, for example, by optimizing the color palette used in the app’s GUI. Whilst past research in this area aimed at optimizing energy while keeping an acceptable level of contrast, this article proposes an approach, named Gui Energy Multi-objective optiMization for Android apps (GEMMA), for generating color palettes using a multi-objective optimization technique, which produces color solutions optimizing energy consumption and contrast while using consistent colors with respect to the original color palette. The empirical evaluation demonstrates (i) substantial improvements in terms of the three different objectives, (ii) a concrete reduction of the energy consumption as assessed by a hardware power monitor, (iii) the attractiveness of the generated color compositions for apps’ users, and (iv) the suitability of GEMMA to be adopted in industrial contexts.
Floating voxels provide new hope for 3D displays
Authors: Edwards Chris
Published: September 2018

In search of holograms that can be viewed from any angle.
The dangers of automating social programs
Authors: Shein Esther
Published: September 2018

Is it possible to keep bias out of a social program driven by one or more algorithms?
Looking Through Broken Windows: The Impact of Neighborhood Disorder on Aggression and Fear of Crime Is an Artifact of Research Design
Authors: O'Brien Daniel T. , Farrell Chelsea , Welsh Brandon C.
Published: September 2018

Broken windows theory (BWT) has heavily influenced social science and policy over the past 30 years. It posits that disorder in neighborhoods leads to elevated crime by inviting additional criminal activity and by discouraging the positive social behavior that prevents crime. Scholars have debated the veracity of BWT, and here we conduct a meta-analysis of 96 studies to examine the effects of disorder on residents’ ( a) general proclivities for aggressive behavior and ( b) perceptions of and attitudes toward their neighborhood (e.g., fear of crime), with particular attention to aspects of research design that might confound causal inference. We found no consistent evidence that disorder induces greater aggression or more negative attitudes toward the neighborhood. Studies that found such effects disproportionately utilized weaker research designs that omit key correlates or confound perceptions of disorder with other neighborhood attitudes. We explore implications for theory, research, and policy.
X-Chromosome Inactivation: A Crossroads Between Chromosome Architecture and Gene Regulation
Authors: Galupa Rafael , Heard Edith
Published: September 2018

In somatic nuclei of female therian mammals, the two X chromosomes display very different chromatin states: One X is typically euchromatic and transcriptionally active, and the other is mostly silent and forms a cytologically detectable heterochromatic structure termed the Barr body. These differences, which arise during female development as a result of X-chromosome inactivation (XCI), have been the focus of research for many decades. Initial approaches to define the structure of the inactive X chromosome (Xi) and its relationship to gene expression mainly involved microscopy-based approaches. More recently, with the advent of genomic techniques such as chromosome conformation capture, molecular details of the structure and expression of the Xi have been revealed. Here, we review our current knowledge of the 3D organization of the mammalian X-chromosome chromatin and discuss its relationship with gene activity in light of the initiation, spreading, and maintenance of XCI, as well as escape from gene silencing.
Evolving Concepts of Mitochondrial Dynamics
Authors: Dorn Gerald W.
Published: September 2018

The concept that mitochondria are highly dynamic is as widely accepted as it is untrue for a number of important contexts. Healthy mitochondria of the most energy-dependent and mitochondrial-rich mammalian organ, the heart, only rarely undergo fusion or fission and are seemingly static within cardiac myocytes. Here, we revisit mitochondrial dynamism with a fresh perspective developed from the recently discovered multifunctionality of mitochondrial fusion proteins and newly defined mechanisms for direct cross talk between mitochondrial dynamics, biogenesis, quality control, and trafficking pathways. Insights gained from comparing static mitochondrial biology in cardiac myocytes and dynamic mitochondrial biology in neurons are reviewed with the goal of understanding contextual fallacies of overly generalized characterizations of these essential and intriguing organelles.
Central Mechanisms for Thermoregulation
Authors: Morrison S.F. , Nakamura K.
Published: September 2018

Maintenance of a homeostatic body core temperature is a critical brain function accomplished by a central neural network. This orchestrates a complex behavioral and autonomic repertoire in response to environmental temperature challenges or declining energy homeostasis and in support of immune responses and many behavioral states. This review summarizes the anatomical, neurotransmitter, and functional relationships within the central neural network that controls the principal thermoeffectors: cutaneous vasoconstriction regulating heat loss and shivering and brown adipose tissue for heat production. The core thermoregulatory network regulating these thermoeffectors consists of parallel but distinct central efferent pathways that share a common peripheral thermal sensory input. Delineating the neural circuit mechanism underlying central thermoregulation provides a useful platform for exploring its functional organization, elucidating the molecular underpinnings of its neuronal interactions, and discovering novel therapeutic approaches to modulating body temperature and energy homeostasis.
Role of α1-adrenoceptor subtypes on corneal epithelial thickness and cell proliferation in mice
Authors: Musayeva Aytan , Manicam Caroline , Steege Andreas , Brochhausen Christoph , Straub Beate K. , Bell Katharina , Pfeiffer Norbert , Gericke Adrian
Published: September 2018

Adrenergic stimuli are important for corneal epithelial structure and healing. The purpose of the present study was to examine the hypothesis that the lack of a single α1-adrenoceptor (α1-AR) subtype affects corneal epithelial thickness and cell proliferation. Expression levels of α1-AR mRNA were determined in mouse cornea using real-time PCR. In mice devoid of one of the three α1-AR subtypes (α1A-AR−/−, α1B-AR−/−, α1D-AR−/−) and in wild-type controls, thickness of individual corneal layers, the number of epithelial cell layers, and average epithelial cell size were determined in cryosections. Endothelial cell density and morphology were calculated in corneal explants, and epithelial cell proliferation rate was determined with immunofluorescence microscopy. Moreover, the ultrastructure of the corneal epithelium was examined by transmission electron microscopy. Messenger RNA for all three α1-AR subtypes was expressed in whole cornea and in corneal epithelium from wild-type mice with a rank order of abundance of α1A ≥ α1B > α1D. In contrast, no α1-AR mRNA was detected in the stroma, and only α1B-AR mRNA was found in the Descemet endothelial complex. Remarkably, corneal epithelial thickness and mean epithelial cell size were reduced in α1A-AR−/− mice. Our findings suggest that the α1A-AR exerts growth effects in mouse corneal epithelial cells.