bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi-Stage Heavy Pill Displacement Using Managed Pressure Tripping Technique in High Pressure-High Temperature Well with Narrow Drilling Margin - A Case Study in Haynesville Shale
Authors: Aliyev Fuad , Yousefi Sadat Ali , Cody Shawn , Huggard Brad , Dametz Sebastian
Published: April 2023

The narrow drilling window of a High Pressure-High Temperature (HPHT) formation creates challenges in managing bottom hole pressure (BHP) during drilling and tripping operations. Managed Pressure Drilling (MPD) techniques have proven effective in accurately controlling downhole pressure, especially in HPHT environments. This study evaluates the capability of automated Managed Pressure Tripping (MPT) techniques in the Haynesville shale gas. The results show that this approach effectively controls the BHP while tripping, resulting in significantly improved operational efficiency, cost, and safety.

MPD hydraulics are developed primarily based on the well profile, mud properties, and drill string dimensions. It uses analytical formulation to compute annular pressure losses along the wellbore every second. Subsequently, the required mud volume, pumping schedule, and applicable surface back pressures (SBP) for the displacement of the heavy pill are simulated to accurately follow the narrow drilling margin. This technique is provided to the field as guidance, and the heavy pill is displaced in multiple stages while maintaining constant bottom-hole pressure through MPD. This method is fully automated, given accurate drilling parameters, and can be controlled remotely from a remote operations center (ROC).

Drilling the deepest HPHT Haynesville wells with a narrow drilling window was successful by using MPD techniques with a mud weight of 16.0 ppg. The pore pressure / stability limit of 17.0 ppg was less than 2% of the formation integrity test (FIT) limit of 17.3 ppg. The MPD hydraulics simulator enables real-time BHP calculations, coupled with a pre-engineered mud schedule, which improves overall tripping efficiency. The heavy pill was displaced in multiple stages during casing and drilling BHA runs based on FIT results. This method resulted in smooth tripping procedures with no reported wellbore stability issues or fluid loss concerns. In comparison to conventional tripping, managing adequate SBP along with a mud pumping schedule allows tripping execution within such a narrow margin. There were no reported observations of wellbore stability issues nor any significant fluid loss concerns. In this case study, the well was drilled to a total depth of 24,100ft MD, and the production casing was successfully run to the planned depth using a multi-stage displacement technique.
Increasing Production by Using A 2-Stages Filtration System with a Gas Separator in Rod Pump
Authors: Vyas Shivani , Wadman Travis , Guanacas Luis , Gonzalez Gustavo
Published: April 2023

To deal with gas and sand problems in their conversion and rod pump wells an operator company in south Texas started introducing a combined technology of two-stages filtration with a modified poor boy gas separator obtaining excellent results. This paper explains the technology used and shares the information used to design the tools and the results achieved in the first wells completed. The screening process to choose the best technology started trying different technologies for gas and sand control below the rod pump. Different technologies were revised sharing data like sand particle size, pump design, fluid production expected and wellbore configuration to get the best design from different companies. The technical and economic evaluation determined the combined system with two-stages filtration and gas separation was the best technology among all the installations. After the results, same technology was applied to other wells changing the configuration based on the well conditions but maintaining the same principle of operation.

After the installation of this technology in each well, it was clear that there was a substantial increase in production among the wells that was caused for the improvement in the pump cards after the installation. The downhole equipment has been able to handle better gas production and no sand problems have been reported so far. The success of this technology has extended the operational capabilities of the pumps allowing the engineers to operate their wells better. Pump cards before and after the installations are summarized in the presentation to show evidence of the good results obtained. After the wells are converted from ESP to rod pump or when the gas represents an issue in the rod pumped wells, the production engineers are limited in the drawdown and the production they can get out of the wells. We are presenting an alternative for the operators to optimize the production's BHA and overcomsand and gas problems that limit the ability to increase the income of the oil fields.
Recommended Practice for Determining the Maximum Surface Injection Pressure for Saltwater Disposal Wells
Authors: Childers David R. , Wu Xingru Wu
Published: April 2023

As more and more water is being co-produced with hydrocarbon, saltwater management has become an important enterprise. Out of many available tools in water management, saltwater disposal through Type II wells is critical to handling large quantities of produced brine. Since the produced water usually contains impurities such as solids, oil and grease, and bacteria, the well's injectivity deteriorates over time as the skin factor develops. Injecting over the formation parting pressure (FPP) gradient may lead to a matrix bypass event and other geohazards; accurately determining the FPP of the target formation is needed to maintain safe injection operations. However, using the step rate test (SRT) doesn't warrant an accurate result. As the target formations can have multilayers with distinct properties, we often find that SRT is often misused.

SRT is often recommended based on oil field operational experience because it is easy to execute and interpret. One fundamental assumption for SRT is that the target formation is a single layer with relative isotropic properties; however, this isn't always true for saltwater disposal wells (SWDs), which usually penetrate through multilayers with very heterogeneous properties. To illustrate our concept, we present a case study using SRT results from an active SWD well located in the Anadarko Basin. We recommend a geomechanical model to determine the operating surface pressure in this paper. The geomechanical model considers the original stresses, variation of geomechanical parameters, injection pressure, and temperature. To consider the uncertainties of these parameters, we demonstrate how to use Monte Carlo simulation to determine the maximum operating surface pressure. We recommend several analyses for the collected data to determine the well's injectivity variation. The Monte Carlo simulation result yields a possible fracturing gradient and presents the probability of each fracturing gradient. Probability is crucial in decision-making as different operators/fields may have different risks, tolerance, and uncertainties. The recommended practice is an integration of data sets and analysis that yield the maximum injection pressure to maintain the well and formation integrity with different risk tolerance levels.
Experimental Study of the Impact of Injection Pressure and Permeability on CO2 Injection into Light Oil Reservoirs
Authors: Enab Khaled Ahmed
Published: April 2023

The miscible gas injection has been a successful technique to overcome the low oil recovery by improving the oil mobility due to viscosity reduction. While many experimental studies defined the fundamentals of gas injection in heavy oil reservoirs, experimental studies of gas injection into condensate oil reservoirs are scarce. Therefore, this study provides a comprehensive investigation of the impact of the injection pressure and reservoir permeability on the efficiency of CO2 to improve oil recovery from oil condensate reservoirs. The efficiency of the injected gas at different injection pressure into different permeability rocks is evaluated as a function of the recovery factor and the viscosity reduction experimentally.

Miscible gas injection experiments of different shale rock samples with different permeabilities saturated with condensate oil were conducted at 5 different injection pressures. The recovery factor will be used to investigate the effect of injection pressure in two distinctly saturated rock samples. These samples are saturated with condensate oil from the Eagle Ford formation. The Minimum Miscible Pressure is predicted from the compositions of the fluids, which is determined using gas chromatography. The gas is injected at different pressures, and the recovery factor is calculated at the gas breakthrough, the end of the injection (Injecting 3 PV), and at the abandonment pressure (100 psi). The viscosity of the collected oil at the end of each run is measured to determine the viscosity reduction value.

The experimental results proved the success of CO2 injection in improving condensate oil production. A proportional relationship between the injection pressure and the recovery factor was observed. Moreover, a proportional relation was observed between the production and the permeability. However, the permeability and the viscosity reduction were observed to be inversely proportional. This observation was extended to the immiscible injection, where the oil viscosity was reduced by a small percentage. This reduction is translated to an existence of some level of miscibility within the pores of the lower permeability sample. This phenomenon could be caused due to the higher nanopore confinement pressure in the lower permeability samples.
Real-Time MPD Hydraulics Simulator: An Alternative Solution to the Conventional Pressure While Drilling Tool - A Case Study
Authors: Pitkanen Jace , Yousefi Sadat Ali , Cody Shawn
Published: April 2023

Narrow pore/stability pressure and fracture pressure margins (narrow operating window) can create severe complications during drilling operations. A slight change in the bottom hole pressure conditions can lead to significant Non-Productive Time (NPT) events like stuck pipe, fluid influx or lost circulation. In many cases, long wells with a narrow gap between pore/stability pressure and fracture pressure are impossible to drill with conventional practices because the annular friction pressure losses (difference between the dynamic and static pressure) are larger than the pore/fracture margin (Arnone & Vieira, 2009). Managed Pressure Drilling (MPD) enables operators to carefully balance between the pore and fracture pressure gradient by counteracting the lack of annular pressure losses (APL) when not circulating with the application of surface back pressure (SBP). MPD has the capability of providing a nearly constant bottomhole pressure with the proper compensation of pressure changes at surface. An accurate and real time determination of change in bottom hole pressure from dynamic effects is necessary to apply the correct SBP. This work investigates the accuracy of a novel approach in real-time MPD hydraulics modelling, which provides an alternative solution to the Pressure-While-Drilling (PWD) tool that measures the downhole annular pressure while drilling. The real-time hydraulics modelling proved to be accurate and allow for adjustments to be continuously made towards optimizing drilling efficiency, reliability, and safety without additional downhole tools.
Biomineralization: Surface Injection Eliminates Bradenhead Pressure
Authors: Hiebert Dwight Randy , Griffin John
Published: April 2023

An oil well in Ohio in the process of being decommissioned had pressure on the 13-3/8" × 9-5/8" annulus. Ohio Department of Natural Resources (ODNR) regulations require gas flow be eliminated prior to abandonment, prompting remediation. Several cement plugs had already been set in the well, preventing access for a traditional perf and squeeze technique to treat the leak without drilling out the plugs.

A biomineralization company was contracted by an operator in Ohio to apply their proprietary biomineralization technology to seal leakage pathways in the cemented annulus via direct injection into the annulus at surface. The operator prepared the well for surface injection by adding lines and valves to the 13-3/8" × 9-5/8" annulus to allow for pumping in the inlet and out the outlet. Biomineralizing fluids were then pumped into the well, where they formed crystalline calcium carbonate in the micro annuli.

Thirty-six hours after the start of treatment, the injection rate had dropped by several orders of magnitude. Subsequent monitoring by a ODNR personnel determined gas flow had been eliminated and the well was approved for permanent abandonment.
Experimental Investigation of Amphoteric and Microbial Surfactants for Enhanced Oil Recovery in Shaly Sandstones
Authors: Pandey Rishabh , Tinni Ali Ousseini , Rai Chandra Shekhar
Published: April 2023

To meet the increasing demand for oil and gas, surfactants have been used to increase hydrocarbon recovery. Use of surfactants reduces the Interfacial Tension (IFT) at fluid/fluid interface and wettability at rock/fluid interface and mobilizes trapped oil out of the pores. However, there are two main limitations of the surfactant flooding process—first, high reservoir temperature & salinity, and second, adsorption of surfactants on the rock surface. Surfactant adsorption alters wettability of reservoir rock from oil-wet to water-wet. However, it may not increase oil recovery, especially in conventional reservoirs with high Total Dissolved Solids (TDS) and temperature due to excess surfactant adsorption. This study tested two synthetic amphoteric surfactants, one nonionic biosurfactant, and a base case with produced brine to understand wettability, IFT, surfactant adsorption, and their effect on oil recovery in shaly sandstone formation. Produced brine has a TDS of 238,000 ppm. First, surfactant stability tests were performed on the three surfactants. Then, IFT measurements were performed between crude oil and surfactant solutions along with produced brine. Next, wettability alteration was studied by measuring contact angle on oil saturated rock samples before and after being exposed with surfactants and produced brine. Then, surfactant adsorption experiments were performed using UV-Vis spectrophotometer to calculate the amount of surfactant adsorbed on the rock sample. Next, surfactants and produced brine imbibition experiments were performed on plug samples at 145°F and 500 psi pressure, and oil recovery was quantified using 12MHz Nuclear Magnetic Resonance (NMR) spectrometer. Results showed that all three surfactants reduced IFT and altered wettability, but biosurfactant showed most reduction of IFT, much lower surfactant adsorption, and made the sample most water wet as compared to amphoteric surfactants. Imbibition experiments showed that biosurfactant have the highest oil recovery, while amphoteric surfactants have oil recovery even lower than produced brine. This study shows that surfactant adsorption effects oil recovery, which can lead to loss of surfactants from solution to the rock surface. This study suggests that biosurfactants with glycolipids can be effectively used in shaly sandstone at high TDS and temperature.
Accessing Healthcare During the COVID-19 Pandemic: Experiences of NYC residents living in North and Central Brooklyn, the South Bronx, and East and Central Harlem
Authors: Dorvil Sheena , Nieves Christina , Valdez Jocelyn , Pierre Jennifer , Dannefer Rachel , Shiman Lauren , Diallo Fatoumata
Published: April 2023

BackgroundThe COVID-19 pandemic has disproportionately affected some New York City (NYC) neighborhoods that primarily consist of Black, Indigenous, and Latino residents. This has been attributed to a longstanding history of structural racism and disinvestment in these communities, resulting in chronic and infectious disease inequities. To help address these health inequities, the NYC Department of Health and Mental Hygiene have utilized placed-based approaches and operated within NYC’s most affected neighborhoods of North and Central Brooklyn, South Bronx, and East and Central Harlem. During the pandemic, these neighborhoods experienced high hospitalization and COVID-related death rates when compared to the rest of NYC. While stay-at-home orders were implemented to reduce the spread of COVID-19, this may have also affected utilization of non-COVID related healthcare services.MethodsTo assess the impact of the pandemic on health and social conditions, the NYC Health Department administered the COVID-19 Community Recovery Survey from September 30, 2021 to November 4, 2021, to 1,358 residents in a subset of these neighborhoods. The survey aimed to assess the prevalence of and reasons for delaying non-COVID related healthcare services during the first 18 months of the pandemic. Quantitative analyses were conducted in SAS Enterprise Guide 7.115 and SAS-Callable SUDAAN and weighted with 2015-2019 American Community Survey 5-year estimates. Qualitative analyses were conducted in Microsoft Excel.ResultsMore than half of participants (54%) delayed routine healthcare or mental health services. Fear of contracting COVID-19 (61%), stay-at-home policies (40%), belief that care could safely be postponed (35%), and appointment challenges (34%) were among reasons for delaying routine healthcare. Fear of contracting COVID-19 (38%) and reduced hours of service (36%) were primary reasons for delaying mental healthcare. Reported reasons for the sustained delay of care past 18 months involved COVID concerns, appointment, and insurance challenges.ConclusionsThe delay of non-COVID related healthcare throughout the pandemic may result in the further widening of the health inequity gap among NYC residents dealing with a higher chronic disease burden before the start of the COVID-19 pandemic in March 2020. Findings from this study can support equitable COVID-19 recovery and guide efforts with health promotion.
A Context Aware Personalized Recommendation System for Home Automation based on Unsupervised and Supervised Learning Algorithms
Authors: Dilekh Tahar , Benharzallah Saber , Mokeddem Ayoub , Kerdoudi Saoueb
Published: April 2023

this paper describes the challenges associated with autonomous home automation systems, which can be inflexible and anxiety-provoking for users who want control over their smart home devices. To address this, the paper proposes a personalized recommender system that considers the user's current state and contextual preferences to suggest relevant automation services for smart home devices. The system uses an unsupervised algorithm to extract behavior rules from past interactions and supervised algorithms to make recommendations based on those rules. Evaluations show that the system is accurate in its recommendations, with an average accuracy of 86.99%, a recall of 76.06%, and a precision of 82.67%.
Complex deformation of cartilage micropellets following mechanical stimulation promotes chondrocyte gene expression
Authors: Petitjean Noémie , Canadas Patrick , Jorgensen Christian , Royer Pascale , Floc'h Simon Le , Noël Danièle
Published: April 2023

Background Articular cartilage (AC)‘s main function is to resist to a stressful mechanical environment and chondrocytes are responding to mechanical stress for the development and homeostasis of this tissue. However, current knowledge on processes involved in response to mechanical stimulation is still limited. These mechanisms are commonly investigated in engineered cartilage models where the chondrocytes are included in an exogeneous biomaterial different from their natural extracellular matrix. The aim of the present study is to better understand the impact of mechanical stimulation on mesenchymal stromal cells (MSCs) derived chondrocytes generated in their own extracellular matrix.
Methods A fluidic custom-made device was used for the mechanical stimulation of cartilage micropellets obtained from human MSCs by culture in a chondrogenic medium for 21 days. Six micropellets were positioned into the conical wells of the device chamber and stimulated with different signals of positive pressure (amplitude, frequency and duration). A camera was used to record the sinking of each micropellet into their cone and micropellet deformation was analyzed using a finite element model. Micropellets were harvested at different time points after stimulation for RT-qPCR and histology analysis.
Results Moderate micropellet deformation was observed during stimulation with square pressure signals as mean Von Mises strains between 6.39% and 14.35% were estimated for amplitudes of 1.75 to 14 kPa superimposed on a base pressure of 50% of the amplitude. The compression, tension and shear observed during deformation did not alter micropellet microstructure as shown by histological staining. A rapid and transient increase in the expression of chondrocyte markers (SOX9, AGG and COL2B) was measured after a single 30-min stimulation with a square pressure signal of 3.5 kPa amplitude superimposed on a minimum pressure of 1.75 kPa, at 1 Hz. A small change of 1% of cyclical deformations when using a square pressure signal instead of a constant pressure signal induced a great fold change of 2 to 3 of chondrogenic gene expression. Moreover, the expression of fibrocartilage (COL I) or hypertrophic cartilage (COL X, MMP13 and ADAMTS5) was not significantly regulated, except for COL X.
ConclusionsOur data demonstrate the interest of fluidic-based compression to stimulate mechanically the growth of cartilage micropellets and set the basis for further investigation of chondrocyte mechanobiology and cartilage-like tissue growth.
Safety profile of rivaroxaban in first-time users treated for venous thromboembolism (deep vein thrombosis and pulmonary embolism) in four European countries
Authors: Ruigómez Ana , Schink Tania , Voss Annemarie , Herings Ron M. C. , Smits Elisabeth , Swart-Polinder Karin , Balabanova Yanina , Brobert Gunnar , Suzart-Woischnik Kiliana , Rodríguez Luis Alberto García
Published: April 2023

BackgroundThe European rivaroxaban post-authorization safety study evaluated bleeding risk among patients initiated on rivaroxaban or vitamin K antagonists for the treatment and secondary prevention of venous thromboembolism in routine clinical practice.MethodsCohorts were created using healthcare databases from the UK, the Netherlands, Germany and Sweden. Patients given a first prescription of rivaroxaban or vitamin K antagonist during the period from December 2011 (in the UK, January 2012) to December 2017 (in Germany, December 2016) for venous thromboembolism indication, with no record of atrial fibrillation or recent cancer history, were observed until the occurrence of each safety outcome that led to hospitalization (intracranial, gastrointestinal, urogenital or other bleeding), or death or until study end (December 2018; in Germany, December 2017). Crude incidence rates of each outcome per 100 person-years were computed, and adjusted odds ratios for risk factors were generated from nested case-control analyses.ResultsOverall, 44 737 rivaroxaban and 45 842 vitamin K antagonist patients were enrolled. Incidence rates were similar between rivaroxaban and vitamin K antagonist users with some exceptions, including higher numerical incidence rates for gastrointestinal bleeding in rivaroxaban users than for vitamin K antagonist users. Rivaroxaban and vitamin K antagonist use was associated with increased bleeding risk compared with non-use. Gastrointestinal bleeding exhibited the most consistent odds ratios (95% confidence interval) across countries, ranging from 2.24 (1.79–2.82) to 4.10 (1.90–8.87) and from 2.24 (1.76–2.84) to 6.76 (2.20–20.80) for rivaroxaban use and vitamin K antagonist use, respectively. Bleeding risks decreased with increasing treatment duration. Among rivaroxaban users, mortality and bleeding risk generally increased with age, renal impairment and diabetes.ConclusionsThese data broadly support safety findings from randomized clinical trials; no unexpected safety concerns related to bleeding risks were found.
Carbon persistence of soils with long-term biosolids amendments in California agroecosystems
Authors: Villa Yocelyn Briceyda , Phosalath Eddie , Ryals Rebecca
Published: April 2023

Biosolids can build soil organic matter, but their ability to increase carbon and nitrogen in persistent fractions in deep soil is not well understood. We aimed to assess the mechanisms that influence soil carbon and nitrogen dynamics at three sites: Sacramento (irrigated, grazed grassland), Solano (rainfed, grazed grassland), and Merced (feed cropping system with alfalfa-corn rotation), where soils were amended with biosolids for 20 years using density fractionations, organo-mineral extractions, and correlations between calcium and soil organic carbon at three depths (0–10 cm, 30–50 cm, 75–100 cm). We found that amended soils had higher carbon and nitrogen content in the free-and occluded light fractions at all depths relative to the control in the Sacramento and Solano sites; however, the Merced site had a greater relative increase of carbon and nitrogen associated with the heavy fraction. Effect sizes show that biosolids increase carbon and nitrogen content in free- and occluded light fractions in the surface soil (0–10 cm), and in both light and heavy fractions in the deep soil layer (75–100 cm). Ratios of carbon to iron and aluminum show that chelation is an important mechanism of carbon stabilization in Sacramento and Solano sites throughout the soil profile. No (0–10 cm) to negative (75–100 cm) correlations were observed between calcium and soil carbon in the amended soils in the Merced site. Our results indicate that, while biosolids are typically incorporated at shallow depths, long-term application of biosolids can increase the amount of free- and occluded-light carbon fractions in deep soil.
Evolutionary suicide and reversal of prey species in a harvested prey-predator system
Authors: Bandyopadhyay Richik , Chattopadhyay Joydev
Published: April 2023

Self-extinction of a species due to evolution is the consequence of the event whenever a mutant prey closer to extinction boundary are at advantage with respect to the resident. In response to the threat of predation, the foraging effort of prey can be considered as an evolving trait. The effects of harvesting in the long-term evolutionary scenario was not investigated theoretically in any of the previous models studied before. Hence we incorporate constant-effort prey and predator harvesting in the model. We also considered individual logistic growth of predator. Our model exhibits i) Evolutionary suicide via a saddle-node bifurcation where, evolution of foraging of prey results in lower forager mutant invasion consequently resulting extinction of prey and ii) Evolutionary reversal via a subcritical Hopf bifurcation where the opposite values of selection gradient at the two alternative demographic attractors causes the cyclic evolution of prey. These contrasting evolutionary scenario is observed due to variation in the choices of harvesting parameters keeping the other parameters fixed which makes the model a study of interest.
Investigating electronic, optical, and structural properties of beryllium oxide zigzag nanotube's using DFT
Authors: Khosravi Mostafa , Badehian Hojat Allah , Zarifi Abbas
Published: April 2023

In this paper, the Electronic and optical properties of beryllium oxide (BeO) zigzag nanotubes (n,0) with n = 6, 8, 10, 12,14, 16 have been studied using GGA and LDA functionals with Siesta code in the framework of density functional theory. According to our findings, these nanotubes exhibit a band gap between 5.0 and 5.7 eV, a buckling of less than 0.063 Å, and a refractive index between 1.05 and 1.1, which is in good agreement with the experimental data of the BeO monolayers. We found that the calculated optical and electronic properties of BeO zigzag nanotubes by GGA-WC, are closer to the monolayer experimental data in comparison to the other functionals.
Udder Traits as a predictor of milk yield in Abergelle Goats: Waghimra zone, Northern Ethiopia
Authors: Aklog Wubneh , Wondim Bekahign , Limeneh Tigabu , Gobeze Mulatu , Wale Yeshwas , Demelie Alemu
Published: April 2023

Milk production and growth are traits with adequate genetic variation to allow selection responses. Accurate prediction of milk yield is a prerequisite for every effective genetic improvement program. This study was conducted to predict milk yield using udder traits in Abergelle goats in the Waghimra zone. Data on milk yield, linear udder score, and udder measurement were collected from 259 healthy and mastitis-free goats at 14-day intervals after one week of parturition, with two measurements in each of the three lactation stages. Linear score traits were scored subjectively using a nine-point linear scale. Parity and management were considered explanatory variables to determine milk yield. The animals were classified into six parity groups. A GLM procedure using SAS/STAT® Software, version 9 of the SAS system for Windows (SAS Institute, Inc., 2002), was used for data analysis. Best-fit models were selected based on the coefficient of determination (R2), correlation coefficient (r), and applicability to farm conditions. As parity increases, milk yield, udder depth, width and teat length increase. When Milk yield was regressed to linear udder measurements, udder circumference explained about 70% of the variation in milk yield. The second udder measurement was udder depth, which contributed 73% of the variation in average daily milk yield. Hence, udder circumference has a predictive ability for milk production, is simple to measure, and is consistent with lactation stage and parity. While adding the depth of the udder to the circumference of the udder could improve the accuracy of the prediction.
Which Mountains Matter to Global Meridional Overturning Circulation?
Authors: Yang Haijun , Huang Jianping , Jiang Rui , Wen Qin , Liu Yimin , Wu Guoxiong
Published: April 2023

The oceanic meridional overturning circulation (MOC) is a key player in the global climate system, while continental topography provides an essential backdrop to the Earth's climate. In this study, we investigate the influence of various mountain ranges on the global thermohaline circulation through a series of coupled model experiments. Our findings reveal that the Tibetan Plateau (TP) exerts the most significant impact on the global thermohaline circulation, serving as a necessary condition for the establishment of the Atlantic MOC (AMOC) and a sufficient condition for the collapse of the Pacific MOC (PMOC). Additionally, the Antarctic continent plays a vital role in facilitating the TP to form the AMOC. Although no individual mountain range can give rise to the AMOC independently, the TP alone can suppress the development of the PMOC. Through altering the global hydrological cycle, the TP may have played a pivotal role in shaping the global thermohaline circulation.
Facility staffing associated with potentially avoidable hospitalizations in nursing home residents in Japan: A retrospective cohort study.
Authors: Hamasaki Yoko , Sakata Nobuo , Jin Xueying , Sugiyama Takehiro , Morita Kojiro , Uda Kazuaki , Matsuda Shinya , Tamiya Nanako
Published: April 2023

Background Wide variations in facility staffing may lead to differences in care, and consequently, adverse outcomes such as hospitalizations. However, few studies focused on types of occupations. Therefore, we aimed to examine the association between a wide variety of facility staffing and potentially avoidable hospitalizations of nursing home residents in Japan.Methods In this retrospective cohort study using long-term care and medical insurance claims data in Ibaraki Prefecture from April 2018 to March 2019, we identified individuals aged 65 years and above who were newly admitted to nursing homes. In addition, facility characteristic data were obtained from the long-term care insurance service disclosure system. Subsequently, we conducted a multivariable Cox regression analysis and evaluated the association between facility staffing and potentially avoidable hospitalizations.Results A total of 2909 residents from 235 nursing homes were included. The cumulative incidence of potentially avoidable hospitalizations at 180 days was 14.2% (95% confidence interval [CI] 12.7–15.8). Facilities with full-time physicians (adjusted hazard ratio [HR]: 0.59, 95% CI: 0.37–0.94) and a higher number of dietitians (HR: 0.72, 95% CI: 0.54–0.97) were significantly associated with a lower likelihood of potentially avoidable hospitalizations. In contrast, having nurses or trained caregivers during the night shift (HR: 1.72, 95% CI: 1.25–2.36) and a higher number of care managers (HR: 1.37, 95% CI: 1.03–1.83) were significantly associated with a high probability of potentially avoidable hospitalizations.Conclusions We revealed that variations in facility staffing were associated with potentially avoidable hospitalizations. The results suggest that optimal allocation of human resources, such as dietitians and physicians, may be essential to reduce potentially avoidable hospitalizations. To provide appropriate care to nursing home residents, it is necessary to establish a system to effectively allocate limited resources. Further research is warranted on the causal relationship between staff allocation and unnecessary hospitalizations, considering the confounding factors.
Pricing Multi-event Triggered Catastrophe Bonds Based on Copula-POT Model
Authors: Tang Yifan , Ling Chengxiu , Wen Conghua , Zhang Yuqing
Published: April 2023

The constantly expanding losses caused by frequent natural disasters pose many challenges to the traditional catastrophe insurance market. The purpose of this paper is to develop an innovative framework for pricing catastrophic bonds triggered by multiple events with extreme dependence structure. Due to the bond's low cash flow contingencies and the CAT bond's high return, the multiple-event CAT bond may successfully transfer the catastrophe risk to the huge financial markets to meet the diversification of capital allocations for most potential investors. The designed hybrid trigger mechanism helps reduce moral hazard and improve bond attractiveness with CIR stochastic rate, displaying the co-movement of the wiped-off coupon and principal, the magnitude and intensity of the natural disaster events involved. As the trigger indicators resulted from the potential catastrophic disaster might be associated with heavy tailed margins, nested Archimedean copulas are introduced with marginal distributions modeled by POT-GP distribution for excess data and common parametric models for moderate risks. To illustrate our theoretical pricing framework, we conduct a statistical analysis of pricing a three-event rainstorm CAT bond based on the resulted losses of rainstorms in China during 2006--2020. Monte Carlo simulations are carried out to analyse the sensitivity of the rainstorm CAT bond price in trigger attachment levels, maturity date, catastrophe intensity, and numbers of trigger indicators.
Mechanical and Durability Assessment of Rockwool-Bamboo Reinforced Ceiling Boards
Authors: Atoyebi Olumoyewa , Kolajo Oluwafemi O. , Alabi Olayinka O. , Aina Salome O
Published: April 2023

It has become important to explore means of reducing deforestation in our environment by sourcing alternatives for timber in the forest. Bamboo (Bambusa vulgaris) as a type of grass grows abundantly in tropical regions around the world. It is known for its strength and flexibility, which makes it a popular material for construction, furniture, and other uses which are still being explored. This paper evaluated the use of bamboo for the design of ceiling boards based on the physical and mechanical properties of bamboo. The research explored the use of bamboo powder, bamboo fibre, and bamboo sticks which are usually wasted during construction activities. Rock wool was used as a fire-resistance agent, and urea-formaldehyde was used as a binding agent. The bamboo ceiling boards were tested for their physical (water absorption, thickness, swelling, and density) and mechanical (modulus of rupture and modulus of elasticity) properties. The results showed the resulting board has the lowest value of 41.885% and the highest value of 86.37% of water absorption and the highest value of 97.564% and the lowest value of 41.885% of water absorption when immersed in water for 2hrs and 24hrs respectively, the modulus of rupture recorded was 78.915 N/mm2 and highest density value of 0.424kg/m3. It was concluded that bamboo is a suitable material for the production of particle and ceiling boards.
Neoadjuvant PD-1/PD-L1 inhibitors combined with chemotherapy had a higher ORR than mono-immunotherapy in untreated HNSCC: Meta-analysis
Authors: Chen Shaoshi , Yang Yifan , Wang Ru , Fang Jugao
Published: April 2023

Background: HNSCC is one of the most common types of cancer worldwide and immune checkpoint inhibitor has shown favorable therapeutic effect in R/M HNSC. However, the application of immunotherapy in untreated HNSCC still needs to be discovered since most R/M HNSCC patients have been treated before and their drug susceptibility and immune tumor microenvironment have changed. This meta-analysis tries to compare immunotherapy and immunochemotherapy in untreated HNSCC and give a reference for clinic application.
Methods: Electronic databases, including PubMed, Embase, and Web of Science, were systematically searched from inception through August 31, 2022. The primary outcomes were efficacy, evaluated by objective response rate, 1-year OS and 1-year PFS, and safety, evaluated by grade 3–4 adverse reaction rate.
Results: A total of 1092 patients from twenty-four studies were included, 282 (25.8%) of which had ORR reported. The average ORR was 37% (95%CI = 26%-49%). Immunochemotherapy could have higher ORR than immunotherapy patients (ORR: 61% vs 22%), and favorable 1-year overall survival from PD-L1 inhibitor (OS = 84%, 95%CI 76%-93%). Radiotherapy after neoadjuvant immunotherapy was equal with the other treatments like chemotherapy and surgery (84% vs 88%, subgroup df p = 0.7). There was no apparent difference between immunotherapy and immunochemotherapy (32% vs 42%, subgroup df p = 0.60).
Conclusion: HNSCC patients could benefit more from neoadjuvant immunochemotherapy.
AMST2: Aggregated Multi-Level Spatial and Temporal Context-Based Transformer for Robust Aerial Tracking
Authors: Park Hasil , Lee Injae , Jeong Dasol , Paik Joonki
Published: April 2023

Recently, many existing visual trackers have made significant progress by incorporating either spatial information from multi-level convolution layers or temporal information for tracking. However, the complementary advantages of both spatial and temporal information cannot be leveraged when these two types of information are used separately. In this paper, we present a new approach for robust visual tracking using a transformer-based model that incorporates both spatial and temporal context information at multiple levels. To integrate the refined similarity maps through multi-level spatial and temporal encoders, we propose an aggregation encoder. Consequently, the output of the proposed aggregation encoder contains useful features that integrate the global contexts of multi-level spatial and the temporal contexts. The contrasting yet complementary representation of multi-level spatial and temporal contexts provided by this feature can help prevent tracking failures in a range of complex aerial scenarios, including occlusion, motion blur, and scale variations. Additionally, the proposed architecture can achieve more robust object tracking against significant variations by updating the features of the latest object while retaining the initial template information. Extensive experiments on five challenging short-term and long-term aerial tracking benchmarks have demonstrated that the proposed tracker outperforms state-of-the-art tracking methods in terms of both real-time processing speed and performance.
Effect of using corn industry wastewater as irrigation water in potato crops (Solanum tuberosum)
Authors: Bacame-Valenzuela Francisco Javier , García-Méndez Liliana Monserrat , Sandoval-Salas Fabiola , Perez-García Jesús Alberto , Aceves-Diez Angel , Reyes-Vidal Yolanda
Published: April 2023

Water scarcity affects more than 40% of the population, in addition, 70% of all water extracted from aquifers is used for irrigation, reducing its availability for human consumption. Therefore, irrigation of crops with wastewater helps reduce water scarcity. In Mexico, high COD-value wastewater is generated by the cooking process of corn (Zea mays). In this work, the use of this effluent for the irrigation of potato crops (Solanum tuberosum) is proposed. Four treatments were applied (A) water, (B) water with fertilizer, (C) 100% residual water, and (D) 50% residual water. In the determination of biomass, in the number of leaves there were no differences between the treatments, instead for the height of the plants, A and B were higher for day 32. Treatment B obtained the highest production of tubers, followed by treatment A. Treatment C achieved 80% of the production of treatment A, suggesting that the components of the wastewater can be used as nutrients by potato plants. Being necessary a study on the affectation on soil fertility.
Adjusting N-doping to balance conductivity and polarization for superb electromagnetic wave absorption properties of SiO2
Authors: He Yunfei , Li Xinyu , Liu Dongdong , Fu Wenbo , Su Qiang , Zhong Bo , Xia Long , Huang Xiaoxiao
Published: April 2023

Due to its low relative permittivity and basically non-electromagnetic loss characteristics, SiO2, a typical electrical insulator, is frequently employed as a wave-transparent material. Hence, using SiO2 as a wave-absorbing material is a novel concept. In this study, a composite (SiO2-Nx) was created using a one-step solvothermal process, doped with N atoms and bound by Si-N bonds. Based on SiO2's imbalanced polarization ability, this research modifies the material's conductivity loss by doping it with N, which successfully balances the polarization and conductivity and turns SiO2-Nx into a wave-absorbing material. The resulting SiO2-N4 composite has a low matched thickness and a wide absorption band of 5.28 GHz with a minimum reflection loss value of -34.48 dB (2.5 mm). The addition of doped-N atoms, which on the one hand improves the impedance matching properties of SiO2-Nx, results in the balanced polarization relaxation and conductivity. The two dielectric loss mechanisms of polarization and conductivity loss, on the other hand, are enhanced to varying degrees by N-doping, which completes the improvement of the wave absorption capability. These outstanding findings offer original suggestions for the creation of SiO2-based electromagnetic wave absorption materials.
Low Coverage of Long Graphene Nanoribbons by On-surface Double Layer Polymerization on Au(111)
Authors: THUPAKULA Umamahesh , Soe We-Hyo , Joachim Christian , Dujardin Erik
Published: April 2023

The controlled surface annealing by steps of 50°C of graphene nanoribbon (GNR) precursors on Au(111) is characterized, during the GNR on-surface synthesis, using low-temperature ultrahigh vacuum scanning tunneling microscopy and dI/dV spectroscopy. The initial monomer coverage is increased up to 3 monolayers (MLs) and annealed at every 50°C. After the first annealing step, the monomers self-organize into 2 ML islands and, then, the Ullmann coupling reaction takes place in both 1st and 2nd MLs. An optimal initial monomer coverage of ~ 1.5 ML is necessary for reaching a final GNR length distribution up to 50 nm and a low surface coverage of 0.4 ML required for single GNR molecule experiments.
Preliminary archaeomagnetic studies of ancient bricks from northern Poland
Authors: Nawrocki Jerzy , Rosowiecka Olga , Wójcik Krystian , Chadima Martin , Werner Tomasz , Wasik Bogusz , Wiewióra Marcin
Published: April 2023

24 brick samples for archaeomagnetic studies were taken from teen historical buildings constructed between c.1280 AD and 1630 AD in northern Poland. Eight of them are from the gothic period. The Thellier-Thellier archaeointensity protocol was used in order to determine the ancient intensity and inclination registered by the bricks. 28 representative specimens from 16 bricks gave successful archaeointensity determination with category B of results quality. For 25 of them the corrections for anisotropy of thermoremanent magnetization and cooling rate were introduced. A large number of specimens classified as category C (48%) is due to a high value of relative additivity check error d(AC) caused most probably by the presence of multi-domain magnetite. Corrected data are convergent with the Central European master curve of archaeointensity. The corrections of raw data reduce their dispersion at specimen/sample level in most of sites.
Estimating Mortality Indicators and Causes of Death Using ANACoD Tool from Civil Registration Data of Iganga-Mayuge HDSS in Uganda
Authors: Habaasa Gilbert , Kajungu Dan
Published: April 2023

Background: Every country requires key population and mortality data to plan for its citizens. Using ANACoD tool, the current study presents the population structure changes for Iganga Mayuge HDSS site in Uganda for the years 2007-2016, computes basic mortality indicators and generates the leading causes of death by age and gender from the civil registration data.
Methods: Secondary data on verbal autopsies as well as the socio-economic data was analysed using Analysis of Mortality levels And Causes-of-Death (ANACoD) tool freely provided by the World Health Organisation.
Results: 3,947 deaths occurred with majority deaths for males (51.5%). Most deaths occurred among the elderly 60+ years (28.1%) and under one (infants) children (23.5%). The population structure has shifted from more infant mortalities (32.1 per 1000 live births) in the year 2007 to less infant mortality (28.1 per 1000 live births) in 2016. Crude Death rate reduced from 4.4 to 3.1 per 1000 population. Life expectancy has increased from 73.7 to 78.7 years. Malaria, HIV, accidents and NCDs remain the major causes of death among adults. In Children, malaria, birth trauma, prematurity and malnutrition are the leading causes of death.
Conclusion: In conclusion, malaria remains the main leading cause of death especially for under-five children for the IMHDSS in Uganda. There is need for strong public health programmes such as sleeping in treated insecticide mosquito nets. Among adults, injury and the Non-Communicable Diseases (NCDs) of Hypertensive disease and Diabetes mellitus have become the more life-threatening cause of death in recent years especially for the older population in the IMHDSS. Improvement in lifestyle among the population through balanced diet feeding and regular exercises is therefore key. Lastly, the paper calls for a strong Civil Registration and Vital Statistics System in Uganda where all deaths in the community and health facilities are effectively registered.