bluuebunny/crossref_metadata_2025 huggingface dataset:
Cross-cultural adaptation and validation of the Arabic version of the knee and hip health-related quality of life (Mini-OAKHQOL) questionnaire in male Saudi patients with osteoarthritis: a methodological observational design
Authors: Alharbi Madi Talal , Ateef Mahamed , Alanazi Ahmad , Alzhrani Msaad
Published: September 2024

Background

Osteoarthritis (OA) is common in Saudi Arabia, has a significant impact on quality of life (QoL), and lacks a specific questionnaire to measure QoL. The primary objective of this study was to translate and cross-culturally adapt the Mini Osteoarthritis Knee and Hip Quality of Life (Mini-OAKHQOL) questionnaire into Arabic and to determine its psychometric properties among OA knee and/or hip patients in Saudi Arabia.

Methods

A methodological observational design was conducted and followed standard guidelines for cross-cultural adaptation of Mini-OAKHQOL into Saudi Arabic. Two hundred and eight primary OA knee and/or hip male participants aged between 45 and 80 years with a mean age of 58.65 ± 13.8 years and a BMI of 29.5 ± 1.2 kg/m2 were included and performed the stages of translation to target Arabic language (forward T1 and T2), synthesized an Arabic draft (T12), then back-translated to English (BT1 and BT2), followed by expert committee review to rectify the deficiencies leading to a prefinal stage involving a pilot test on native Arabic speakers, thereby finalized a final Arabic version. The Arabic Mini-OAKHQOL, Arabic Short Form 12 (SF12), and visual analog scale (VAS) were administered to analyze internal consistency (IC), test–retest reliability at baseline as well as one week later (up to the 10th day). The construct validity was tested using Spearman’s rank correlation, and factor analysis was done to establish a five-factor fit model. Homogeneity was determined using principal component analysis (PCA). Floor and ceiling effects calculated in percentages.

Results

The Arabic Mini-OAKHQOL showed an excellent Cronbach’s alpha of the overall scale (α = 0.931) for its internal consistency and an excellent intraclass correlation coefficient (ICC) of 0.947 for its retest reliability, with a high response rate of 93.75%. The construct validity of this scale was good with Ar-SF12 and VAS pain. A five-factor model fit was considered acceptable, and factor loading for each item found within the permissible limits confirmed the factorial validity. None of the items, dimensions, or overall scale showed either a floor or ceiling effect.

Conclusion

The adapted and tested Arabic Mini-OAKHQOL is a reliable and valid questionnaire to measure the impact of knee and/or hip OA on quality of life in the Saudi Arabian male OA population to reduce the respondent’s burden for use in clinical and prospective studies.
Inefficacy of mallard flight responses to approaching vehicles
Authors: Guenin Shane , Pakula Carson J. , Skaggs Jonathon , Fernández-Juricic Esteban , DeVault Travis L.
Published: September 2024

Vehicle collisions with birds are financially costly and dangerous to humans and animals. To reduce collisions, it is necessary to understand how birds respond to approaching vehicles. We used simulated (i.e., animals exposed to video playback) and real vehicle approaches with mallards (Anas platyrynchos) to quantify flight behavior and probability of collision under different vehicle speeds and times of day (day vs. night). Birds exposed to simulated nighttime approaches exhibited reduced probability of attempting escape, but when escape was attempted, fled with more time before collision compared to birds exposed to simulated daytime approaches. The lower probability of flight may indicate that the visual stimulus of vehicle approaches at night (i.e., looming headlights) is perceived as less threatening than when the full vehicle is more visible during the day; alternatively, the mallard visual system might be incompatible with vehicle lighting in dark settings. Mallards approached by a real vehicle exhibited a delayed margin of safety (both flight initiation distance and time before collision decreased with speed); they are the first bird species found to exhibit this response to vehicle approach. Our findings suggest mallards are poorly equipped to adequately respond to fast-moving vehicles and demonstrate the need for continued research into methods promoting effective avian avoidance behaviors.
Comparative postoperative prognosis of ceramic-on-ceramic and ceramic-on-polyethylene for total hip arthroplasty: an updated systematic review and meta-analysis
Authors: Wu Tingyu , Jiang Yaping , Shi Weipeng , Wang Yingzhen , Li Tao
Published: September 2024

Objective

To compare the clinical outcomes between ceramic-on-ceramic (CoC) and ceramic-on-polyethylene (CoP) bearing surfaces in patients undergoing total hip arthroplasty (THA) through a pooled analysis and evidence update.

Methods

We performed a systematic literature search using PubMed, Embase, Cochrane Library and Web of Science up to March 2023 for studies that compared the bearing surfaces of CoC and CoP in patients undergoing THA. The primary outcomes were the incidence of common postoperative complications and the rate of postoperative revision. The secondary outcome was the Harris Hip Score.

Results

A total of 10 eligible studies involving 1,946 patients (1.192 CoC-THA versus 906 CoP-THA) were included in the evidence synthesis. Pooled analysis showed no significant difference in the rates of common postoperative complications (dislocation, deep vein thrombosis, infection, wear debris or osteolysis) and of revision. After eliminating heterogeneity, the postoperative Harris Hip Score was higher in the CoC group than in the CoP group. However, the strength of evidence was moderate for the Harris Hip Score.

Conclusion

CoC articulations are more commonly used in younger, healthier, and more active patients. While the performance of conventional polyethylene is indeed inferior to highly cross-linked polyethylene, there is currently a lack of sufficient research comparing the outcomes between highly cross-linked polyethylene and CoC bearing surfaces. This area should be a focal point for future research, and it is hoped that more relevant articles will emerge. Given the limited number of studies included, the heterogeneity and potential bias of those included in the analysis, orthopaedic surgeons should select a THA material based on their experience and patient-specific factors, and large multicentre clinical trials with >15 years of follow-up are needed to provide more evidence on the optimal bearing surface for initial THA.
Preoperative fibrinogen level predicts the risk and prognosis of patients with native valve infective endocarditis undergoing valve surgery
Authors: Li Jia , Zhao Junyong , Sun Ning , Zhang Lijiao , Su Qing , Xu Wei , Luo Xiaolin , Gao Zhichun , Zhu Keting , Zhou Renjie , Qin Zhexue
Published: September 2024

Aim

The aim of this study was to assess the clinical significance and prognostic value of the preoperative fibrinogen (FBG) level in patients with native valve infective endocarditis (NVIE) who underwent valve surgery.

Methods

This retrospective study included a total of 163 consecutive patients who were diagnosed with NVIE and underwent valve surgery from January 2019 to January 2022 in our hospital. The primary endpoint was all-cause mortality.

Results

All-cause mortality was observed in 9.2% of the patients (n = 15). Body mass index (BMI) was lower in the survival group (p = 0.025), whereas FBG (p = 0.008) and platelet count (p = 0.044) were significantly greater in the survival group than in the death group. Multivariate Cox proportional hazards analysis revealed that FBG (HR, 0.55; 95% CI, [0.32–0.94]; p = 0.029) was an independent prognostic factor for all-cause mortality. Furthermore, Kaplan‒Meier survival curve analysis revealed that patients with low FBG levels (<3.28 g/L) had a significantly greater mortality rate (p = 0.034) than did those with high FBG levels (>3.99 g/L). In the trend analysis, the FBG tertiles were significantly related to all-cause mortality in all three adjusted models, and the p values for trend were 0.017, 0.016, and 0.028, respectively.

Conclusion

Preoperative FBG may serve as a prognostic factor for all-cause mortality, and an FBG concentration less than 3.28 g/L was associated with a greater risk of all-cause mortality in NVIE patients undergoing valve surgery.
Content quality and reliablity of YouTube™ videos as a source of information about good oral hygiene practices in adults
Authors: Ince Kuka Gizem , Gursoy Hare
Published: September 2024

Background

Good oral hygiene is crucial for preventing dental caries and periodontal diseases. However, proper and regular application of oral hygiene practices requires adequate knowledge. In recent years, the internet has become one of the most popular places to find health-related information, necessitating studies that analyze the quality of the content available online. The purpose of the present study was to analyze the content quality and reliability of YouTube™ videos on the topic of adult oral hygiene practices and to guide oral health care professionals who use this platform for patient education.

Methods

A YouTube™ search was performed of the most frequent search term, ‘dental hygiene’. A total of 150 videos were screened, and 51 were included in the final study. The characteristics, sources, and content of the videos were analyzed using the Global Quality Score (GQS) and DISCERN reliability indices. The IBM SPSS 25 program was used for statistical analyses.

Results

Most of the included videos were uploaded by oral health care professionals (63%). GQS revealed only 17.6% of the videos were excellent quality whereas 23.5% of them were poor quality. In the content analysis, 62.7% of the videos were deemed moderately useful. Video duration, total content score, and interaction indices were all significantly higher in the useful and very useful groups compared to the slightly useful group (p = 0.020, p < 0.001, p = 0.040). GQS had a positive, low-medium statistically significant correlation with both video duration and total content scores (r = 0.235, r = 0.517; p < 0.05). DISCERN score also had a positive, low-medium statistically significant correlation with total content score (r = 0.500; p < 0.05).

Conclusion

The study concluded that most YouTube™ videos on oral hygiene practices for adults are moderately useful. When using YouTube™ for patient education, oral health care professionals and organizations should be aware of low-quality videos and seek out accurate, useful videos. There is also a need for quality videos with expanded oral health content.
Optimization of Mango Leaf Disease Detection Using a Hybrid Machine Learning Approach
Authors: Ballo Abou Bakary , Coulibaly Adama , Diaby Moustapha
Published: September 2024

Mango cultivation is essential in northern Côte d'Ivoire, substantially contributing to the national economy. However, microbial diseases affecting mango leaves represent a significant challenge for farmers. Early detection of these diseases is crucial for effective crop management and plantation protection. Infrastructure constraints limit the ability to detect mango leaf diseases early. To deal with this challenge, a new approach based on artificial intelligence has been developed to detect and classify mango leaf diseases. The study is based on two methodological approaches. Firstly, we use machine learning algorithms, including Random Forests, Support Vector Machines (SVMs), and eXtreme Gradient Boosting (XGBoosting). In parallel, a second approach incorporates Convolutional Neural Networks (CNNs) to extract complex visual features from leaf images. These features are combined with the three machine learning algorithms mentioned above for classification. The results show that the second approach, which combines CNNs with machine learning algorithms, outperforms the first. In particular, the accuracy of the second approach, with CNNs combined with SVMs, stands out, achieving the highest accuracy scores. The performance of the VGG16-SVM, ResNet-SVM, and VGG19-SVM models are evaluated with high precision and accuracy scores, respectively. These results offer promising prospects for the practical application of these techniques in fields such as medical image classification, materials analysis, and other areas where spectroscopy is used as a classification tool.
Physiotherapy as Holistic Care in Pregnancy: A Literature Review
Authors: Bhatia Smriti , Bhargava Nilesh , Sharma Pooja , Chauhan Sarvotam
Published: September 2024

Introduction: Physiotherapy deals with the overall physicaldevelopment of an individual. In pregnancy, there are pregnancy related disorders, such as gestational weight gain, gestational diabetes, pelvic muscle dysfunction and incontinence. Regular physical exercise during pregnancy is associated with numerous benefits. Aim: To gather best evidence about the effectiveness of exercise and modalities during pregnancy. Materials and Methods: Random controlled trails and studies from Google scholar, Pubmed and Physiotherapy Evidence Database (PEDro) that were published from 2019-2023 were reviewed. These studies included the trail of modalities during parturition and various forms of exercises during pregnancy. After reviews from these studies, a concise review has been formed suggesting the effectiveness of physiotherapy in pregnancy. Results: Out of 15 papers that were selected 13 showed a positive impact of exercise and TENS in pregnancy and parturition respectively. Physiotherapy in case of pregnancy had shown a significant impact on gestational period, parturition Pelvic floor strengthening held in easy carrying of the foetus and exercises were found to prevent the gestational weight gain along with it, Pelvic floor strengthening helped in management of stress incontinence. Conclusion: The whole study showed a positive impact of physiotherapy during pregnancy. The implementation of physiotherapy and modalities has the potential to reduce labor pain. Pregnant women who exercise have been shown to have a shorter labor and easier deliveries and possesses greater selfesteem.
Impact of Aerobic Exercise Training on Sleep Quality in Adults with Somatic Dysfunction
Authors: Batra Aryan , Goyal Kanu , Goyal Manu
Published: September 2024

Introduction: It has been demonstrated that aerobic exercise improves cardiovascular health and endurance. Patients with somatic dysfunction have low quality sleep, and training in aerobic exercise is important for enhancing the quality of the patients’ sleep. Training with aerobic exercises includes cycling, running, and brisk walking. Aim: To study that aerobic exercise improves sleep quality in adults with somatic dysfunction. Materials and Methods: Databases such as PubMed/Medline, Google Scholar, Scopus, Cochrane were explored to uncover fulltext publications authored in English and were searched to retrieve desired articles. In addition, reference list of the retrieved article were searched in the analysis process. Result: A total 278 articles are retrieved after removing duplicates articles, only 3 articles were evaluated in this literature review. Conclusion: It has been concluded that aerobic exercise training improves sleep quality in adults with somatic dysfunction. Aerobic exercise training has shown promising effects on sleep quality among adults with somatic dysfunction. Research indicates that regular aerobic activity can improve sleep duration, efficiency, and overall quality. By reducing stress and promoting relaxation, aerobic exercise contributes to better sleep patterns, potentially enhancing the well-being of individuals with somatic dysfunction. Implementation: Aerobic exercise protocols are employed to raise physical health and improve sleep quality in adults.
Attitude of Onion Growers towards Drip Irrigation System in Tamil Nadu, India
Authors: M Asokhan, , Abinaya A. , T.N.Sujeetha
Published: September 2024

The drip irrigation system is a kind of micro-irrigation system that has the potential to salvage the water and other nutrients by entrance water to drip gradually to the main roots if plants and other plant parts, which is from on the soil surface or buried inside the soil surface. The main aim of drip irrigation is to place water directly into the main root zone and decrease the water vapour. This study investigates the attitude of Onion growing farmers towards drip irrigation system. The survey was conducted to collect primary data from 119 onion growing farmers in Thondamuthur block of Coimbatore district. Findings reveal that less than three-fifths (57.14%) of the respondents expressed neutral attitude level towards drip irrigation system followed by 21.85 per cent had favourable and 21.01 per cent of the respondents had un-favourable attitude level towards drip irrigation system respectively. This study recommends the implementation of an extensive agricultural institution with more prevalent and periodic visits to drip owners should be established in order to provide regular technical advice and valuable data on the maintenance and repair of the drip irrigation scheme. Such initiatives could enhance the livelihood status of the onion growing farmers in Tamil Nadu.
Effect of Enriched Phosphocompost on Soil Biological Properties of Pearl Millet in Vertisols
Authors: M. Dhokchawle Kanchan , S. Thakare Ritu , B. Margal Prasad
Published: September 2024

A field experiment was laid out with ten treatments replicated thrice in Randomized Block Design. Treatments comprised of  T1: control, T2: 100% RDF, T3: 100% RDF + 2.5 t bajra straw phosphocompost ha-1, T4: 100% RDF + 2.5 t cotton stalk phosphocompost ha-1, T5: 100% RDF + 2.5 t FYM ha-1, T6: 100% RDF + 5 t FYM ha-1, T7: 75% RDF + 2.5 t bajra straw phosphocompost ha-1, T8: 75% RDF + 2.5 t cotton stalk phosphocompost ha-1, T9: 75% RDF + 2.5 t FYM ha-1 and T10: 75% RDF + 2.5 t FYM ha-1. Soil biological properties were estimated at sowing, at flowering and harvesting of pearl millet. The experimental findings indicated that the soil microbial biomass were found to be increased at flowering than at sowing and further, gradually declined at harvest but higher than sowing stage. The significantly maximum soil microbial biomass C (212.42 µg C g-1 soil), N (70.72 µg N g-1 soil) and P (40.25 µg P g-1) soil contents were recorded with 100% RDF + 2.5 t cotton stalks phosphocompost ha-1 (T4) followed by 100% RDF + 2.5 t bajra straw phosphocompost ha-1 (T3) at flowering. Among the FYM treatments, the higher SMBC, N and P were noted with 100% RDF + 5 t FYM ha-1 over 100% RDF alone. Further, it was noticed that C and N mineralization rate were increased at flowering stage and then declined at harvest as compare to sowing stage. However, at harvest, the highest C (9.12 µg C g-1 soil d-1) and N (0.86 µg N g-1 soil d-1) mineralization were recorded with 100% RDF + 2.5 t cotton stalks phosphocompost ha-1 (T4) followed by 100% RDF + 2.5 t bajra straw phosphocompost ha-1 (T3). Significantly maximum dehydrogenase activity (61.17 µg TPF g-1 soil 24 hr-1), alkaline phosphatase activity (90.43µgP- Nitrophenol g-1 soil 24 hr-1), fungal (23 × 104cfu g-1 soil), bacterial (43 × 107cfu g-1 soil) and actinomycetes (41 × 106cfu g-1 soil) population were noted in the treatment receiving 100% RDF + 2.5 t cotton stalks phosphocompost ha-1 (T4).
Effect of Biostimulants and Nutrient Management on Soil Nutrients Level in Onion (Allium cepa L.)
Authors: Saini Anubha , Kumari Santosh , Chaudhary Parveen
Published: September 2024

During rabi season of 2021, a field experiment was conducted by embracing different organic manures, inorganic fertilizers and biostimulants (Pseudomonas fluorescens and Bacillus subtilis) over growth, yield, quality and persisting soil fertility of onion in the mineralized soils of Himachal Pradesh. The study was organized in thirteen treatments. The analysis revealed that lowest soil pH (6.94), electrical conductivity (0.186 dSm-1), highest soil organic carbon (0.85%), available nitrogen (257.79 kg/ha) and available phosphorus (26.14 kg/ha) were recorded with treatment T7 [75% RDF + 40 kg S/ha + Bacillus subtilis + FYM (250 q/ha)]. The highest available potassium was recorded in treatment T12 [100% RDF (125:75:60 kg/ha)] and highest available sulphur was recorded in treatment in T11 [100% RDF + 40 kg S/ha].
A Multi-criterian Approach to Identify Groundwater Potential Zones in the Subarnarekha River Basin Using Integrated Analytical Hierarchy Process and Geospatial Technology
Authors: Sharma Rupa , Pandey Rahul Kumar , Singh Abhay Krishna
Published: September 2024

The intense extraction of groundwater and changing climate patterns have strained global groundwater supplies. As the demand for drinkable water rises worldwide, assessing groundwater availability and aquifer output becomes increasingly important. Geographic information systems (GIS) are being used more frequently for groundwater exploration due to their speed and provision of preliminary data. This study focuses on mapping groundwater availability in a minor tropical river basin in India, using a combination of GIS and the analytical hierarchy process (AHP). Ten thematic layers were generated and analyzed, including Geology, Geomorphology, Land use and land cover (LULC), Lineament density, Drainage density, Rainfall, Soil type, Slope, Topographic Wetness Index ( TWI), and curvature to delineate groundwater potential zones. AHP was employed to assign weights to each category based on their water retention properties. The resulting map was validated against existing groundwater data, demonstrating an accuracy of approximately 85%. The groundwater potential zones were classified as high, moderate, and, low. The moderate potential zone covered 59% of the basin, while the low and high potential zones constituted 29% and 11% respectively. High and low potential regions were limited to small sections of the basin. In conclusion, this research successfully mapped the groundwater availability in the Rarhu River watershed using GIS and AHP. The findings highlight the distribution of different groundwater potential zones, providing valuable information for sustainable water resource management in the area.
AP Statistic for Identification of Outliers in Multi-Response Experiments with Correlated Errors
Authors: Prem Gaddala , Ojha Sankalpa
Published: September 2024

In multi response experiments where correlated errors are present, identification of outliers becomes a complex yet crucial task. Outliers not only distort the estimation of model parameters but also jeopardize the validity of statistical inferences drawn from the data. In the present study the statistic given by Andrews and Pregibon (AP) (1978) for detection of influential observations in linear regression is suitably modified for detection of outliers in multi – response experiments with correlated errors. The statistic was developed considering the data structure of auto – regressive order 1.  The outlier detection is based on mean – shift method, in which the expected value of the outlying observation is different from the expected values of other observations. The developed statistic is successful in detection of outliers when tested upon simulated datasets.
Split‐BioID: a proximity biotinylation assay for dimerization‐dependent protein interactions
Authors: De Munter Sofie , Görnemann Janina , Derua Rita , Lesage Bart , Qian Junbin , Heroes Ewald , Waelkens Etienne , Van Eynde Aleyde , Beullens Monique , Bollen Mathieu
Published: December 2016

The biotin identification (BioID) protocol uses a mutant of the biotin ligase BirA (BirA*) fused to a protein‐of‐interest to biotinylate proximate proteins in intact cells. Here, we show that two inactive halves of BirA* separately fused to a catalytic and regulatory subunit of protein phosphatase PP1 reconstitute a functional BirA* enzyme upon heterodimerization of the phosphatase subunits. We also demonstrate that this BirA* fragment complementation approach, termed split‐BioID, can be used to screen for substrates and other protein interactors of PP1 holoenzymes. Split‐BioID is a novel and versatile tool for the identification of (transient) interactors of protein dimers.
A preliminary 1‐D model investigation of tidal variations of temperature and chlorinity at the Grotto mound, Endeavour Segment, Juan de Fuca Ridge
Authors: Xu G. , Larson B. I. , Bemis K. G. , Lilley Marvin D.
Published: December 2016

Tidal oscillations of venting temperature and chlorinity have been observed in the long‐term time series data recorded by the Benthic and Resistivity Sensors (BARS) at the Grotto mound on the Juan de Fuca Ridge. In this study, we use a one‐dimensional two‐layer poroelastic model to conduct a preliminary investigation of three hypothetical scenarios in which seafloor tidal loading can modulate the venting temperature and chlorinity at Grotto through the mechanisms of subsurface tidal mixing and/or subsurface tidal pumping. For the first scenario, our results demonstrate that it is unlikely for subsurface tidal mixing to cause coupled tidal oscillations in venting temperature and chlorinity of the observed amplitudes. For the second scenario, the model results suggest that it is plausible that the tidal oscillations in venting temperature and chlorinity are decoupled with the former caused by subsurface tidal pumping and the latter caused by subsurface tidal mixing, although the mixing depth is not well constrained. For the third scenario, our results suggest that it is plausible for subsurface tidal pumping to cause coupled tidal oscillations in venting temperature and chlorinity. In this case, the observed tidal phase lag between venting temperature and chlorinity is close to the poroelastic model prediction if brine storage occurs throughout the upflow zone under the premise that layers 2A and 2B have similar crustal permeabilities. However, the predicted phase lag is poorly constrained if brine storage is limited to layer 2B as would be expected when its crustal permeability is much smaller than that of layer 2A.
Rapid variations in fluid chemistry constrain hydrothermal phase separation at the Main Endeavour Field
Authors: Love Brooke , Lilley Marvin , Butterfield David , Olson Eric , Larson Benjamin
Published: December 2016

Previous work at the Main Endeavour Field (MEF) has shown that chloride concentration in high‐temperature vent fluids has not exceeded 510 mmol/kg (94% of seawater), which is consistent with brine condensation and loss at depth, followed by upward flow of a vapor phase toward the seafloor. Magmatic and seismic events have been shown to affect fluid temperature and composition and these effects help narrow the possibilities for sub‐surface processes. However, chloride‐temperature data alone are insufficient to determine details of phase separation in the upflow zone. Here we use variation in chloride and gas content in a set of fluid samples collected over several days from one sulfide chimney structure in the MEF to constrain processes of mixing and phase separation. The combination of gas (primarily magmatic CO2 and seawater‐derived Ar) and chloride data, indicate that neither variation in the amount of brine lost, nor mixing of the vapor phase produced at depth with variable quantities of (i) brine or (ii) altered gas rich seawater that has not undergone phase separation, can explain the co‐variation of gas and chloride content. The gas‐chloride data require additional phase separation of the ascending vapor‐like fluid. Mixing and gas partitioning calculations show that near‐critical temperature and pressure conditions can produce the fluid compositions observed at Sully vent as a vapor‐liquid conjugate pair or as vapor‐liquid pair with some remixing, and that the gas partition coefficients implied agree with theoretically predicted values.
Geochemical and microstructural evidence for interseismic changes in fault zone permeability and strength, Alpine Fault, New Zealand
Authors: Boulton Carolyn , Menzies Catriona D. , Toy Virginia G. , Townend John , Sutherland Rupert
Published: December 2016

Oblique dextral motion on the central Alpine Fault in the last circa 5 Ma has exhumed garnet‐oligoclase facies mylonitic fault rocks from ∼35 km depth. During exhumation, deformation, accompanied by fluid infiltration, has generated complex lithological variations in fault‐related rocks retrieved during Deep Fault Drilling Project (DFDP‐1) drilling at Gaunt Creek, South Island, New Zealand. Lithological, geochemical, and mineralogical results reveal that the fault comprises a core of highly comminuted cataclasites and fault gouges bounded by a damage zone containing cataclasites, protocataclasites, and fractured mylonites. The fault core‐alteration zone extends ∼20–30 m from the principal slip zone (PSZ) and is characterized by alteration of primary phases to phyllosilicate minerals. Alteration associated with distinct mineral phases occurred proximal the brittle‐to‐plastic transition (T ≤ 300–400°C, 6–10 km depth) and at shallow depths (T = 20–150°C, 0–3 km depth). Within the fault core‐alteration zone, fractures have been sealed by precipitation of calcite and phyllosilicates. This sealing has decreased fault normal permeability and increased rock mass competency, potentially promoting interseismic strain buildup.
Formation of hydrothermal pits and the role of seamounts in the Guatemala Basin (Equatorial East Pacific) from heat flow, seismic, and core studies
Authors: Villinger H. W. , Pichler T. , Kaul N. , Stephan S. , Pälike H. , Stephan F.
Published: December 2016

We acquired seismic and heat flow data and collected sediment cores in three areas in the Guatemala Basin (Cocos Plate, Eastern Pacific) to investigate the process by which depressions (pits) in the sedimentary cover on young oceanic crust were formed. Median heat flow of 55 mW/m2 for the three areas is about half of the expected conductive cooling value. The heat deficit is caused by massive recharge of cold seawater into the upper crust through seamounts which is inferred from depressed heat flow in the vicinity of seamounts. Heat flow inside of pits is always elevated, in some cases up to three times (max. 300 mW/m2) relative to background. None of the geochemical pore water profiles from cores inside and outside of the pits show any evidence of active fluid flow inside the pits. All three areas originated within the high productivity equatorial zone and moved northwest over the past 15 to 18 Ma. Pits found in the working areas are likely relict dissolution structures formed by diffuse hydrothermal venting in a zone of high biogenic carbonate production which were sealed when they moved north. It is likely that these pits were discharge sites of “hydrothermal siphons” where recharging seamounts could feed cold seawater via the upper crust to several discharging pits. Probably pit density on the whole Cocos Plate is similar to the three working areas and which may explain the huge heat deficit of the Cocos Plate.
An experimental model of episodic gas release through fracture of fluid confined within a pressurized elastic reservoir
Authors: Rocco Stefano , Woods Andrew W. , Harrington Jon , Norris Simon
Published: December 2016

We present new experiments that identify a mechanism for episodic release of gas from a pressurized, deformable reservoir confined by a clay seal, as a result of the transition from bulk deformation to channel growth through the clay. Air is injected into the center of a thin cylindrical cell initially filled with a mixture of bentonite clay and water. For sufficiently dry mixtures, the pressure initially increases with little volume change. On reaching the yield stress of the clay‐water mixture, the lid of the cell then deforms elastically and an air‐filled void forms in the center of the cell as the clay is driven radially outward. With continued supply of air, the pressure continues to increase until reaching the fracture strength of the clay. A fracture‐like channel then forms and migrates to the outer edge of the cell, enabling the air to escape. The pressure then falls, and the clay flows back toward the center of the cell and seals the channel so the cycle can repeat. The phenomena may be relevant at mud volcanoes.
Automated force‐free flux rope identification
Authors: Smith A. W. , Slavin J. A. , Jackman C. M. , Fear R. C. , Poh G.‐K. , DiBraccio G. A. , Jasinski J. M. , Trenchi L.
Published: December 2016

We describe a method developed to automatically identify quasi force‐free magnetotail flux ropes from in situ spacecraft magnetometer data. The method locates significant (greater than 1σ) deflections of the north‐south component of the magnetic field coincident with enhancements in other field components. The magnetic field data around the deflections are then processed using Minimum Variance Analysis (MVA) to narrow the selection down to those that exhibit the characteristics of flux ropes. The subset of candidates that fulfills the requirements are then compared to a cylindrical, linear (constant‐α) force‐free model. Those that can be well approximated as force free are then accepted. The model fit also provides a measure of the physical parameters that describe the flux rope (i.e., core field and radius). This process allows for the creation of a repeatable, consistent catalog of flux ropes. Automation allows a greater volume of data to be covered, saving time and allowing the exploration of potential selection biases. The technique is applied to MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) magnetometer data in the Hermean magnetotail and successfully locates flux ropes, some of which match previously known encounters. Assumptions of the method and potential future applications are discussed.
Whistler mode waves upstream of Saturn
Authors: Sulaiman A. H. , Gurnett D. A. , Halekas J. S. , Yates J. N. , Kurth W. S. , Dougherty M. K.
Published: December 2016

Whistler mode waves are generated within and can propagate upstream of collisionless shocks. They are known to play a role in electron thermodynamics/acceleration and, under certain conditions, are markedly observed as wave trains preceding the shock ramp. In this paper, we take advantage of Cassini's presence at ~10 AU to explore the importance of whistler mode waves in a parameter regime typically characterized by higher Mach number (median of ~14) shocks, as well as a significantly different interplanetary magnetic field structure, compared to near Earth. We identify electromagnetic precursors preceding a small subset of bow shock crossings with properties which are consistent with whistler mode waves. We find these monochromatic, low‐frequency, and circularly polarized waves to have a typical frequency range of 0.2–0.4 Hz in the spacecraft frame. This is due to the lower ion and electron cyclotron frequencies near Saturn, between which whistler waves can develop. The waves are also observed as predominantly right handed in the spacecraft frame, the opposite sense to what is typically observed near Earth. This is attributed to the weaker Doppler shift, owing to the large angle between the solar wind velocity and magnetic field vectors at 10 AU. Our results on the low occurrence of whistler waves upstream of Saturn also underpin the predominantly supercritical bow shock of Saturn.
Comparison between low‐pressure laboratory discharges and atmospheric sprites
Authors: Robledo‐Martinez A. , Garcia‐Villarreal A. , Sobral H.
Published: December 2016

The discharge of a charged dielectric in low‐pressure air has characteristics that resemble some of the features of mesospheric discharges. The dielectric discharges in steps when the pressure of the surrounding air is gradually reduced from nearly atmospheric to ~0.01 torr. The setup employed here decouples the discharge from the power supply, and, thanks to that, unique properties of the discharge manifest themselves. For example, in the pressure interval ~10–100 torr streamers are emitted from the surface of the dielectric but when the pressure decreases to 2–16 torr these are replaced by spherically symmetrical discharges that we call peonies. These have interesting properties, like (a) they do not produce electrical field, (b) they remain static, and (c) their size increases with decreasing pressure. The peonies are a type of discharge that has not been reported before. They resemble sprite beads and are assumed to consist of large avalanches that do not lead to the formation of a streamer. At further lower pressures, in the interval 0.01–0.1 torr, diffuse volume discharges were observed that have some morphological similarities with sprite halos and the top of columnar sprites. The spectrographic measurements carried out show that the discharges have bands from the first and second positive systems in N2 as well as lines of N2+. Quenching of the first negative system of N2 was observed at 3 torr. In this work it was also observed how a cosmic ray can go on to trigger a discharge inside the experimentation chamber.
Tsunamis generated by long and thin granular landslides in a large flume
Authors: Miller Garrett S. , Andy Take W. , Mulligan Ryan P. , McDougall Scott
Published: December 2016

In this experimental study, granular material is released down slope to investigate landslide‐generated waves. Starting with a known volume and initial position of the landslide source, detailed data are obtained on the velocity and thickness of the granular flow, the shape and location of the submarine landslide deposit, the amplitude and shape of the near‐field wave, the far‐field wave evolution, and the wave runup elevation on a smooth impermeable slope. The experiments are performed on a 6.7 m long 30° slope on which gravity accelerates the landslides into a 2.1 m wide and 33.0 m long wave flume that terminates with a 27° runup ramp. For a fixed landslide volume of 0.34 m3, tests are conducted in a range of still water depths from 0.05 to 0.50 m. Observations from high‐speed cameras and measurements from wave probes indicate that the granular landslide moves as a long and thin train of material, and that only a portion of the landslide (termed the “effective mass”) is engaged in activating the leading wave. The wave behavior is highly dependent on the water depth relative to the size of the landslide. In deeper water, the near‐field wave behaves as a stable solitary‐like wave, while in shallower water, the wave behaves as a breaking dissipative bore. Overall, the physical model observations are in good agreement with the results of existing empirical equations when the effective mass is used to predict the maximum near‐field wave amplitude, the far‐field amplitude, and the runup of tsunamis generated by granular landslides.
Mixing efficiency in the thermocline of lakes observed from eddy correlation flux measurements
Authors: Weck Julika , Lorke Andreas
Published: December 2016

Vertical mixing in the thermocline of lakes is poorly understood and most of the current knowledge is based on ex situ methods like laboratory measurements and simulations. Here we used the eddy correlation technique (EC) to directly measure oxygen and buoyancy fluxes in the thermocline of two lakes (Lake Scharmützelsee and Lake Arendsee in 2012 and 2013, respectively). Additionally, sets of temperature microstructure profiles (SCAMP) were measured during the EC deployments. We used these data to quantify the mixing efficiency as well as the turbulent diffusivity. The derived turbulent diffusivities from EC for the Prandtl number of DO were one order of magnitude higher than predicted by commonly applied parameterization, while the diffusivities for the Prandtl number of heat confirmed the parameterization. The results from EC and SCAMP showed strong differences which we attribute to the fact that SCAMP measurements reflect snapshots of the instantaneous turbulence field while EC provides a temporal average of the prevailing turbulence. Finally, we discuss problems of the EC and the inertial dissipation method in a strongly stratified environment and propose how they could be improved to resolve the full temporal variability of mixing in thermoclines.
The importance of deep, basinwide measurements in optimized Atlantic Meridional Overturning Circulation observing arrays
Authors: McCarthy G. D. , Menary M. B. , Mecking J. V. , Moat B. I. , Johns W. E. , Andrews M. B. , Rayner D. , Smeed D. A.
Published: December 2016

The Atlantic Meridional Overturning Circulation (AMOC) is a key process in the global redistribution of heat. The AMOC is defined as the maximum of the overturning stream function, which typically occurs near 30°N in the North Atlantic. The RAPID mooring array has provided full‐depth, basinwide, continuous estimates of this quantity since 2004. Motivated by both the need to deliver near real‐time data and optimization of the array to reduce costs, we consider alternative configurations of the mooring array. Results suggest that the variability observed since 2004 could be reproduced by a single tall mooring on the western boundary and a mooring to 1500 m on the eastern boundary. We consider the potential future evolution of the AMOC in two generations of the Hadley Centre climate models and a suite of additional CMIP5 models. The modeling studies show that deep, basinwide measurements are essential to capture correctly the future decline of the AMOC. We conclude that, while a reduced array could be useful for estimates of the AMOC on subseasonal to decadal time scales as part of a near real‐time data delivery system, extreme caution must be applied to avoid the potential misinterpretation or absence of a climate time scale AMOC decline that is a key motivation for the maintenance of these observations.
Satellite observation of particulate organic carbon dynamics on the Louisiana continental shelf
Authors: Le Chengfeng , Lehrter John C. , Hu Chuanmin , MacIntyre Hugh , Beck Marcus W.
Published: December 2016

Particulate organic carbon (POC) plays an important role in coastal carbon cycling and the formation of hypoxia. Yet, coastal POC dynamics are often poorly understood due to a lack of long‐term POC observations and the complexity of coastal hydrodynamic and biogeochemical processes that influence POC sources and sinks. Using field observations and satellite ocean color products, we developed a new multiple regression algorithm to estimate POC on the Louisiana Continental Shelf (LCS) from satellite observations. The algorithm had reliable performance with mean relative error (MRE) of ∼40% and root mean square error (RMSE) of ∼50% for MODIS and SeaWiFS images for POC ranging between ∼80 and ∼1200 mg m−3, and showed similar performance for a large estuary (Mobile Bay). Substantial spatiotemporal variability in the satellite‐derived POC was observed on the LCS, with high POC found on the inner shelf (<10 m depth) and lower POC on the middle (10–50 m depth) and outer shelf (50–200 m depth), and with high POC found in winter (January–March) and lower POC in summer to fall (August–October). Correlation analysis between long‐term POC time series and several potential influencing factors indicated that river discharge played a dominant role in POC dynamics on the LCS, while wind and surface currents also affected POC spatial patterns on short time scales. This study adds another example where satellite data with carefully developed algorithms can greatly increase the spatial and temporal observations of important biogeochemical variables on continental shelf and estuaries.
Low‐CCN concentration air masses over the eastern North Atlantic: Seasonality, meteorology, and drivers
Authors: Wood Robert , Stemmler Jayson D. , Rémillard Jasmine , Jefferson Anne
Published: December 2016

A 20 month cloud condensation nucleus concentration (NCCN) data set from Graciosa Island (39°N, 28°W) in the remote North Atlantic is used to characterize air masses with low cloud condensation nuclei (CCN) concentrations. Low‐CCN events are defined as 6 h periods with mean NCCN<20 cm−3 (0.1% supersaturation). A total of 47 low‐CCN events are identified. Surface, satellite, and reanalysis data are used to explore the meteorological and cloud context for low‐CCN air masses. Low‐CCN events occur in all seasons, but their frequency was 3 times higher in December–May than during June–November. Composites show that many of the low‐CCN events had a common meteorological basis that involves southerly low‐level flow and rather low wind speeds at Graciosa. Anomalously low pressure is situated to the west of Graciosa during these events, but back trajectories and lagged SLP composites indicate that low‐CCN air masses often originate as cold air outbreaks to the north and west of Graciosa. Low‐CCN events were associated with low cloud droplet concentrations (Nd) at Graciosa, but liquid water path (LWP) during low‐CCN events was not systematically different from that at other times. Satellite Nd and LWP estimates from MODIS collocated with Lagrangian back trajectories show systematically lower Nd and higher LWP several days prior to arrival at Graciosa, consistent with the hypothesis that observed low‐CCN air masses are often formed by coalescence scavenging in thick warm clouds, often in cold air outbreaks.
Contributions of volatile and nonvolatile compounds (at 300°C) to condensational growth of atmospheric nanoparticles: An assessment based on 8.5 years of observations at the Central Europe background site Melpitz
Authors: Wang Zhibin , Birmili Wolfram , Hamed Amar , Wehner Birgit , Spindler Gerald , Pei Xiangyu , Wu Zhijun , Cheng Yafang , Su Hang , Wiedensohler Alfred
Published: December 2016

Long‐term measurements of particle number size distributions in combination with thermodenuder analysis have been performed since July 2003 at the Central European station of Melpitz, Germany. Up to the end of 2011, 20% of all investigated days during the 8.5 years of measurements showed new particle formation and subsequent growth. To investigate the role of various chemical compound candidates for condensational nanoparticle growth, we focused on nucleation events in which the measured size distributions with and without thermodesorption both showed growth patterns (accounting for up to ~85% of all nucleation events). In this study, particulate compounds that volatilize at 300°C were specifically defined as “volatile,” in contrast to “nonvolatile” compounds, which remain in the particulate phase after being heated to 300°C. A strong correlation between ambient temperature and growth rate associated with volatile substances (except gaseous sulfuric acid) was found, which implies the importance of organics (possibly oxidized biogenic organic compounds) in particle growth at Melpitz. The contributions of the volatile compounds to the growth rate due to condensation of gaseous sulfuric acid and organics were found to be about 19% and 47%, respectively. The remaining ~25% was attributed to nonvolatile residuals, which appear to form gradually during the particle growth process and are characterized as extremely low‐volatility compounds. The growth rate associated with volatile components exhibited significant seasonal variation, with the highest value during summertime, whereas the growth rate associated with the nonvolatile fraction showed less fluctuation.