bluuebunny/crossref_metadata_2025 huggingface dataset:
Unraveling volcanic and related processes using remotely sensed data sets: Perspectives from a Miocene-aged volcanic terrain in northwest Arizona
Authors: Lang* Nicholas P. , McDowell Susanne M. , Nypaver Cole A. , Gibson Brandt M. , Li-Vidal Briana , Miller Calvin F. , Claiborne Lily L. , Helfrich Autumn , McCosby Joseph , Schwat Eli , Thompson Ian P. , Wallrich Blake , Foley Michelle , McGuinness Sarah , Gomez Carlos
Published: November 2019

This field trip will visit the southern Black Mountains volcanic center (SBMVC) and its associated products in northwestern Arizona. Post-volcanic extension and erosion of this semi-arid area afford the opportunity to examine a Miocene-aged (ca. 19–17 Ma) volcanic terrain in detail, using an approach that integrates fieldwork, petrography and geochemistry, and remotely sensed data. This approach was recently used in a three-year National Science Foundation Research Experience for Undergraduate (NSF REU) program, from which some results will be highlighted. This integrated approach can provide insight into the amounts and types of information that can be gleaned from various types of remotely sensed data of a volcanic terrain. Over three days, we will work our way through the volcanic section associated with the SBMVC as exposed near Oatman and Kingman, Arizona, to observe: (1) felsic to mafic shallow intrusions; (2) deposits from felsic to intermediate explosive and effusive eruptions; (3) deposits from sedimentary processes; and (4) the results of subsequent extensional faulting. The petrologic, physical volcanic, and morphologic characteristics of observed outcrops will be discussed at each field stop, and will be used as points of discussion while in the field, for observations of presumably volcanic terrains on other planetary bodies. An appended road log serves as a geologic guide to this volcanic center and associated rocks.
Regional-scale evolution of the Laramide arc and porphyry copper province, southwestern North America
Authors: Greig Roy E. , Barton Mark D.
Published: November 2019

Porphyry copper provinces are time-space clusters of porphyry copper deposits (PCDs) that form in magmatic arcs. The evolution of the Laramide arc of southwestern North America, which hosts the Laramide porphyry copper province—the second-largest in the world—provides insight into factors contributing to its transient and localized metallogenic fertility. Regional-scale patterns are evident based on new and compiled U-Pb geochronological and whole-rock geochemical data, collected as part of an ongoing study. The migration of the locus of PCD formation coupled with shut-off of the magmatic arc and other geological evidence suggest localization of PCD formation near the southern margin of a shallowly subducting portion of the Farallon plate. Trends in increasing maximum size of PCDs and increasing SiO2 content of magmas with time correlate with the duration of arc activity in a given locale. Collectively, these trends suggest a variety of processes, including (1) uncertain ones related to local tectonic configuration, and (2) variations in crustal assimilation and/or metasomatism, which are correlated to the local duration of arc magmatism, contributed to the richness of the Laramide porphyry copper province.
Mesozoic to Cenozoic sedimentation, tectonics, and metallogeny of Sonora, Mexico
Authors: Price* Jason B. , Calmus Thierry , Bennett Scott E.K. , Ochoa-Landín Lucas
Published: November 2019

We will embark on a five-day journey through northern, western, and central Sonora, in which we will see excellent examples of mostly Mesozoic to Cenozoic tectonics, sedimentation, and metallogeny. On Day 1, we will visit the porphyry copper deposit at Ajo, Arizona, and several Pleistocene cinder cones and maar craters in the Pinacate Biosphere Reserve. On Day 2, we will see L- and L-S tectonites at the type locality of the Mojave-Sonora megashear in Sierra Los Tanques, Noche Buena orogenic gold deposit, Ediacaran Gamuza beds in Caborca, and have an overview of the Carnero detachment fault on the south side of Sierra La Gloria. Day 3 will explore faults and related sedimentary and volcanic rocks associated with the late Miocene oblique opening of the Gulf of California rift and visit outcrops that record late Miocene timing constraints for flooding of the Gulf of California seaway, including several localities on southern Isla Tiburón accessible only by boat. Day 4 will visit exposures of Permian sedimentary to Paleogene igneous rocks in Hermosillo (Cerro La Campana); Puerto del Sol detachment fault zone; Aconchi batholith and a hot spring localized on a Basin and Range normal fault; Santa Elena low-sulfidation epithermal gold mine; and the Upper Jurassic Cucurpe Formation. On Day 5, we will visit several exposures of different crustal levels of the Magdalena-Madera metamorphic core complex, including the spectacular stretched pebble conglomerates in Arroyo Amolares.
Back to the Jurassic: Architecture of eolian, wadi, microbialite, and disturbed facies, Carmel Formation and Navajo Sandstone, Kane County, south-central Utah
Authors: Caputo Mario V. , Anderson Thomas B.
Published: November 2019

Two sites in Kane County, south-central Utah, were selected for this two-day field trip. Stunning outcrop examples of the internal structure of eolian, wadi, and microbialite beds are accessible in the Middle Jurassic Carmel Formation at White House camp along the Paria River, and outcrop details of deformed bedding are accessible in the Lower Jurassic Navajo Sandstone on Wire Pass/Coyote Wash trail. Respective facies are described and interpreted within a theme of “back to basics in sedimentology” and within a landscape framework of the Grand Staircase and the East Kaibab monocline. A tan, cross-bedded facies of coastal eolian origin and a red lenticular facies of wadi origin in the Thousand Pockets Member, Carmel Formation, were coeval with a wavy laminated facies of organo-sedimentary origin in the Judd Hollow Tongue of the Carmel Formation. Grainflow, wind-ripple, and grainfall processes conspired on Jurassic dunes to deposit a cross-bed array of eolian sandflow, wind-ripple, and grainfall foreset strata, and wind-ripple and possibly grainfall toeset strata in the tan cross-bedded facies. Episodes of wadi flooding are preserved in the red lenticular facies as cyclical, upward-fining sandstones-mudstones punctuated by exposure and mudcrack fills. They locally and temporarily interrupted eolian sedimentation before being overrun and buried by eolian dunes. Ripples and microbes built up the wavy laminated facies at a supratidal marine shoreline of the Middle Jurassic seaway. Ground-shaking from an earthquake or extraterrestrial impact triggered severe deformation of eolian dune sand in the disturbed facies of the Navajo Sandstone.
The “Holey Tour” planetary geology field trip, Arizona
Authors: Greeley† Ronald
Published: November 2019

Arizona has a wide variety of geological features relevant to planetary geology. The “Holey Tour” is a 2 d field trip (Phoenix-Flagstaff-Phoenix) that introduces participants to crater forms (hence the “holes” of the tour), including a maar, karst sinkhole, pit crater, cinder-cone craters, a volcano-tectonic depression, and the classic impact structure Meteor Crater. The Apollo astronaut field training site near Flagstaff is examined, which includes a terrain that was artificially generated to simulate a cratered lunar surface. In addition, planetary volcanism is discussed with stops that include a shield volcano, composite cone, silicic dome, and cinder cones; considerations include key variables in volcanic morphology, such as lava composition and rates of effusion. The general geology of Arizona is discussed throughout the trip and includes parts of the Colorado Plateau, the Basin and Range Province, and the Central Highlands (also called the “transition” zone). The trip can be adapted to meet the needs of any group, from secondary school students to established planetary scientists.

This field trip generally follows the GSA guide published in GSA Special Paper 483 (available at https://pubs.geoscienceworld.org/gsa):

Greeley, R., 2011, The “Holey Tour” planetary geology field trip, Arizona, in Garry, W.B., and Bleacher, J.E., eds., Analogs for Planetary Exploration: Geological Society of America Special Paper 483, p. 377–391, https://doi.org/10.1130/2011.2483(23).
Histopathology of retinoblastoma eyes enucleated after intra-arterial chemotherapy
Authors: Biewald Eva Maria , Bornfeld Norbert , Metz Klaus A , Schlüter Sabrina , Kiefer Tobias , Radbruch Alexander , Göricke Sophia , Sirin Selma , Ketteler Petra , Bechrakis Nikolaos E
Published: November 2019

Background

To demonstrate histopathological findings in retinoblastoma eyes enucleated after intra-arterial chemotherapy (IAC) with special emphasis on vascular toxicity and local tumour control.

Methods

Retrospective study with a consecutive series of 23 retinoblastoma eyes enucleated after IAC where histopathological work-up was available.

Results

From November 2010 to June 2019 23 eyes were enucleated after the attempt of eye salvaging therapy with IAC using melphalan. IAC was the first line treatment in nine and salvage treatment in 14 eyes. Doses of melphalan ranged from 3 to 7.5 mg, whereby a strict protocol with age-appropriate dosage was not used until 2015. The mean number of treatment cycles was 1.8. The main indications for enucleation were poor treatment response or tumour progression in 14 eyes, severe vascular complications in five eyes and a total exudative retinal detachment with amaurosis in the remaining four eyes. We found active disease in 15 eyes with an indication for adjuvant chemotherapy due to high risk factors for metastases in four eyes. To date none of these patients developed metastatic disease. Concerning vascular toxicity, we detected a central retinal artery occlusion in three eyes, severe vasculitis in another three, ischaemic outer retina atrophy and choroidal ischaemia in seven eyes with one eye developing a severe proliferative retinopathy.

Conclusion

IAC is a highly effective treatment option for advanced retinoblastoma, but the described potential risks should be kept in mind. These include severe vascular complications, as well as the possibility of persisting vital tumour cells fulfilling high-risk criteria for adjuvant chemotherapy.
Redefining typhoid diagnosis: what would an improved test need to look like?
Authors: Mather Richard G , Hopkins Heidi , Parry Christopher M , Dittrich Sabine
Published: November 2019

Introduction

Typhoid fever is one of the most common bacterial causes of acute febrile illness in the developing world, with an estimated 10.9 million new cases and 116.8 thousand deaths in 2017. Typhoid point-of-care (POC) diagnostic tests are widely used but have poor sensitivity and specificity, resulting in antibiotic overuse that has led to the emergence and spread of multidrug-resistant strains. With recent advances in typhoid surveillance and detection, this is the ideal time to produce a target product profile (TPP) that guides product development and ensure that a next-generation test meets the needs of users in the resource-limited settings where typhoid is endemic.

Methods

A structured literature review was conducted to develop a draft TPP for a next-generation typhoid diagnostic test with minimal and optimal desired characteristics for 36 test parameters. The TPP was refined using feedback collected from a Delphi survey of key stakeholders in clinical medicine, microbiology, diagnostics and public and global health.

Results

A next-generation typhoid diagnostic test should improve patient management through the diagnosis and treatment of infection with acuteSalmonella entericaserovars Typhi or Paratyphi with a sensitivity ≥90% and specificity ≥95%. The test would ideally be used at the lowest level of the healthcare system in settings without a reliable power or water supply and provide results in <15 min at a cost of <US$1.00.

Conclusion

This report outlines the first comprehensive TPP for typhoid fever and is intended to guide the development of a next-generation typhoid diagnostic test. An accurate POC test will reduce the morbidity and mortality of typhoid fever through rapid diagnosis and treatment and will have the greatest impact in reducing antimicrobial resistance if it is combined with diagnostics for other causes of acute febrile illness in a treatment algorithm.
Over-the-counter antibiotic dispensing by pharmacies: a standardised patient study in Udupi district, India
Authors: Nafade Vaidehi , Huddart Sophie , Sulis Giorgia , Daftary Amrita , Miraj Sonal Sekhar , Saravu Kavitha , Pai Madhukar
Published: November 2019

Background

Antimicrobial resistance is a global health emergency, and one of the contributing factors is overuse and misuse of antibiotics. India is one of the world’s largest consumers of antibiotics, and inappropriate use is potentially widespread. This study aimed to use standardised patients (SPs) to measure over-the-counter antibiotic dispensing in one region.

Methods

Three adults from the local community in Udupi, India, were recruited and trained as SPs. Three conditions, in both adults and children, were considered: diarrhoea, upper respiratory tract infection and acute fever. Adult SPs were used as proxies for the paediatric cases.

Results

A total of 1522 SP interactions were successfully completed from 279 pharmacies. The proportion of SP interactions resulting in the provision of an antibiotic was 4.34% (95% CI 3.04% to 6.08%) for adult SPs and 2.89% (95% CI 1.8% to 4.4%) for child SPs. In the model, referral to another provider was associated with an OR 0.38 (95% CI 0.18 to 0.79), the number of questions asked was associated with an OR 1.54 (95% CI 1.30 to 1.84) and an SP–pharmacist interaction lasting longer than 3 min was associated with an OR 3.03 (95% CI 1.11 to 8.27) as compared with an interaction lasting less than 1 min.

Conclusion

Over-the-counter antibiotic dispensing rate was low in Udupi district and substantially lower than previously published SP studies in other regions of India. Dispensing was lowest when pharmacies referred to a doctor, and higher when pharmacies asked more questions or spent more time with clients.
The effect of chronic, non-specific low back pain on superficial lumbar muscle activity: a protocol for a systematic review and meta-analysis
Authors: Sanderson Andy , Rushton Alison B , Martinez Valdes Eduardo , Heneghan Nicola R , Gallina Alessio , Falla Deborah
Published: November 2019

Introduction

Chronic, non-specific low back pain is a major global cause of disability. One factor which might potentially contribute to ongoing pain is maladaptive variation in the level of activity in the lumbar musculature. Several studies have investigated this activity using surface electromyography, in varied muscles and during a number of functional activities. Due to differences in the applied methodology, the results have been difficult to compare, and previous reviews have been limited in scope. In this protocol, we aim to perform a comprehensive review of the effect of chronic low back pain on lumbar muscle activity.

Methods and analysis

This protocol was informed by the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols (PRISMA-P) and results will be reported in line with the PRISMA. Searches will be conducted on the Web of Science, PubMed, MEDLINE, EMBASE, ZETOC and CINAHL databases, along with a comprehensive review of grey literature and key journals. One reviewer will conduct the searches, but two independent reviewers will screen potential studies and assess the risk of bias within studies which meet the inclusion criteria. The Newcastle-Ottawa risk of bias tool, and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) guidelines will be used to assess the quality of the data. Meta-analysis will be conducted where appropriate on groups of studies with homogenous methodology. Where studies are too heterogeneous to allow for meta-analysis, meta-synthesis will instead be completed, comparing results in terms of net increases or decreases of activity.

Ethics and dissemination

This review aims to identify common adaptations of muscle activity in people with low back pain and it is expected that the results will influence future research directions and future rehabilitation approaches. The results will be submitted for publication in a peer-reviewed journal and presented at conferences.

Prospero registration number

CRD42019125156
Recent adverse mortality trends in Scotland: comparison with other high-income countries
Authors: Fenton Lynda , Minton Jon , Ramsay Julie , Kaye-Bardgett Maria , Fischbacher Colin , Wyper Grant M A , McCartney Gerry
Published: November 2019

Objective

Gains in life expectancy have faltered in several high-income countries in recent years. Scotland has consistently had a lower life expectancy than many other high-income countries over the past 70 years. We aim to compare life expectancy trends in Scotland to those seen internationally and to assess the timing and importance of any recent changes in mortality trends for Scotland.

Setting

Austria, Croatia, Czech Republic, Denmark, England and Wales, Estonia, France, Germany, Hungary, Iceland, Israel, Japan, Korea, Latvia, Lithuania, Netherlands, Northern Ireland, Poland, Scotland, Slovakia, Spain, Sweden, Switzerland and USA.

Methods

We used life expectancy data from the Human Mortality Database (HMD) to calculate the mean annual life expectancy change for 24 high-income countries over 5-year periods from 1992 to 2016. Linear regression was used to assess the association between life expectancy in 2011 and mean life expectancy change over the subsequent 5 years. One-break and two-break segmented regression models were used to test the timing of mortality rate changes in Scotland between 1990 and 2018.

Results

Mean improvements in life expectancy in 2012–2016 were smallest among women (<2 weeks/year) in Northern Ireland, Iceland, England and Wales, and the USA and among men (<5 weeks/year) in Iceland, USA, England and Wales, and Scotland. Japan, Korea and countries of Eastern Europe had substantial gains in life expectancy over the same period. The best estimate of when mortality rates changed to a slower rate of improvement in Scotland was the year to 2012 quarter 4 for men and the year to 2014 quarter 2 for women.

Conclusions

Life expectancy improvement has stalled across many, but not all, high-income countries. The recent change in the mortality trend in Scotland occurred within the period 2012–2014. Further research is required to understand these trends, but governments must also take timely action on plausible contributors.
Effects of physical activity and sedentary behaviour on cardiometabolic risk factors and cognitive function in children: protocol for a cohort study
Authors: Lv Yajie , Cai Li , Gui Zhaohuan , Zeng Xia , Tan Minyi , Wan Nianqing , Lai Lijuan , Lu Shaomin , Tan Weiqing , Chen Yajun
Published: November 2019

Introduction

Although studies showed that physical activity (PA) and sedentary behaviour (SB) were associated with cardiometabolic risk factors and cognitive function, both independent and combined associations among them are inconsistent. Cardiometabolic risk factors are also associated with cognitive function, but research of children is limited. Additionally, the brain level mechanisms have not been fully established. The proposed study aims to explore the associations and mechanisms of PA and SB on cognitive function and cardiometabolic risk factors in children.

Methods and analysis

This is a school-based prospective cohort study. A total of 8324 participants of this study are primary school students aged 7–12 years old who are followed up every 2 years from January 2017 to December 2026. We used a stratified cluster random sampling to select five primary schools in Guangzhou, China. There are three phases at baseline. At phase I, we collect PA, SB and cognitive function by questionnaires and also conduct anthropometric and biochemical measurements in all participants. At phase II, PA, SB and cognitive function are measured respectively by accelerometers and cognitive tasks among participants randomly selected from four subgroups with different SB and PA levels. At phase III, event-related potentials are recorded using electroencephalogram during a cognitive task among participants randomly selected from phase II. We plan to follow-up all participants until they graduate from high school. The process applied at baseline and follow-up are approximately identical.

Ethics and dissemination

Procedures described in this manuscript have been approved by the Ethical Review Committee for Biomedical Research, School of Public Health, Sun Yat-sen University (L2016-010). All parents or guardians of participants signed the informed consent form voluntarily before participating in the study. The findings of the study will be published in peer-reviewed journals.

Trial registration number

NCT03582709
Association of Intestinal Permeability with Admission Vitamin D Deficiency in Patients who are Critically Ill
Authors: Eslamian Ghazaleh , Ardehali Seyed Hossein , Hajimohammadebrahim-Ketabforoush Melika , Vahdat Shariatpanahi Zahra
Published: November 2019

Emerging data have led to the hypothesis that vitamin D plays a role in promoting epithelial barrier dysfunction. Therefore, intestinal permeability becomes a significant determiner in the future of patients hospitalized in intensive care unit (ICU). The relationship between vitamin D and intestinal permeability remains unclear in patients who are critically ill. The aim of the study is to document the relationship between the admission vitamin D deficiency and markers of intestinal permeability in the critical care setting. This was a single-center, observational, prospective study in the general ICU of a university-affiliated hospital. A sample of 144 ICU-hospitalized adult patients was recruited between January and May 2018. The admission serum 25-hydroxyvitamin D levels were measured and categorized as <20 and ≥20 ng/dL, respectively. Moreover, the admission plasma endotoxin and zonulin concentrations as markers of intestinal permeability were determined in stringent conditions. The association between markers of intestinal permeability and 25-hydroxyvitamin D levels was assessed adjusting for potential confounders through an estimation of a binary logistic regression model. Our results showed that median plasma endotoxin and zonulin decreased with increasing serum levels of vitamin D categories (p=0.001) in the overall study population. Multivariate binary logistic regression analyses showed a significant association between the plasma endotoxin (OR 0.12, 95% CI 0.03 to 0.52) and zonulin (OR 0.91, 95% CI 0.87 to 0.99) levels with serum levels of vitamin D categories in the overall population. Our finding suggests a relationship between vitamin D deficiency and early alterations in intestinal permeability. Thus, evaluating vitamin D levels in patients who are critically ill may be warranted.
IntronicSMCHD1variants in FSHD: testing the potential for CRISPR-Cas9 genome editing
Authors: Goossens Remko , van den Boogaard Marlinde L , Lemmers Richard J L F , Balog Judit , van der Vliet Patrick J , Willemsen Iris M , Schouten Julie , Maggio Ignazio , van der Stoep Nienke , Hoeben Rob C , Tapscott Stephen J , Geijsen Niels , Gonçalves Manuel A F V , Sacconi Sabrina , Tawil Rabi , van der Maarel Silvère M
Published: November 2019

Background

Facioscapulohumeral dystrophy (FSHD) is associated with partial chromatin relaxation of theDUX4retrogene containing D4Z4 macrosatellite repeats on chromosome 4, and transcriptional de-repression ofDUX4in skeletal muscle. The common form of FSHD, FSHD1, is caused by a D4Z4 repeat array contraction. The less common form, FSHD2, is generally caused by heterozygous variants inSMCHD1.

Methods

We employed whole exome sequencing combined with Sanger sequencing to screen uncharacterised FSHD2 patients for extra-exonicSMCHD1mutations. We also used CRISPR-Cas9 genome editing to repair a pathogenic intronicSMCHD1variant from patient myoblasts.

Results

We identified intronicSMCHD1variants in two FSHD families. In the first family, an intronic variant resulted in partial intron retention and inclusion of the distal 14 nucleotides of intron 13 into the transcript. In the second family, a deep intronic variant in intron 34 resulted in exonisation of 53 nucleotides of intron 34. In both families, the aberrant transcripts are predicted to be non-functional. Deleting the pseudo-exon by CRISPR-Cas9 mediated genome editing in primary and immortalised myoblasts from the index case of the second family restored wild-type SMCHD1 expression to a level that resulted in efficient suppression ofDUX4.

Conclusions

The estimated intronic mutation frequency of almost 2% in FSHD2, as exemplified by the two novel intronicSMCHD1variants identified here, emphasises the importance of screening for intronic variants inSMCHD1. Furthermore, the efficient suppression ofDUX4after restoring SMCHD1 levels by genome editing of the mutant allele provides further guidance for therapeutic strategies.
Jean McKinlay Anderson
Authors: Munro Helen , Duncanson Graham ,   Jean's family
Published: November 2019

A pioneering vet who enjoyed a remarkable career. After working in large mixed practices in the UK, her sense of adventure took her to Kenya, where she became the first female in the state's vet service.
Tensile strength of sands treated with microbially induced carbonate precipitation
Authors: Nafisi Ashkan , Mocelin Douglas , Montoya Brina M. , Underwood Shane
Published: November 2019

During large earthquake events where bending moments within soil cements are induced, the tensile strength of cemented soil may govern the deformational behavior of improved ground. Several studies have been conducted to assess the tensile strength of artificially cemented sands that use Portland cement or gypsum; however, the tensile strength of microbially induced carbonate precipitation (MICP)-treated sands with various particle sizes measured through direct tension tests has not been evaluated. MICP is a biomediated improvement technique that binds soil particles through carbonate precipitation. In this study, the tensile strength of nine specimens were measured by conducting direct tension tests. Three types of sand (coarse, medium, and fine) were cemented to reach a heavy level of cementation (e.g., shear wave velocity of ∼900 m/s or higher). The results show that the tensile strength varies between 210 and 710 kPa depending on sand type and mass of carbonate. Unconfined compressive strength (UCS) tests were performed for each sand type to assess the ratio between tensile strength and UCS in MICP-treated sands. Scanning electron microscopy (SEM) images and surface energy measurements were used to determine the predominant failure mode at particle contacts under tensile loading condition.
Effect of different sediment dewatering techniques on subsequent particle sizes in industrial derived effluent
Authors: Alimohammadi M. , Tackley H.A. , Lake C.B. , Spooner I. , Walker T.R. , Jamieson R. , Gan C. , Bossy K.
Published: November 2019

A paucity of literature has compared geotextile dewatering methods to more conventional dewatering methods (i.e., centrifuge, sedimentation) in the context of how geotextile dewatering performs at reducing particulate matter in dewatering effluent. Particulate matter is the primary source of inorganic and organic contaminants (i.e., dioxins and furans) in an unconsolidated sediment (estimated 577 000 m3) that has accumulated in a wastewater stabilization basin in Nova Scotia, Canada. Physical and chemical properties of contaminated sediment were initially characterized, and subsequent laboratory experiments were carried out for three common dewatering methods: sedimentation, centrifugation, and geotextile filtration. Filtrate quality of suspended solids (number, particle size distribution of particles) was examined for differences based on three dewatering techniques assessed. All three methods provided effective removal of particulate matter during dewatering, but geotextile dewatering could be a more cost-effective and practical solution for dewatering of these sediments.
Evidence of volcanic activity in the growth rings of trees at the Tacaná volcano, Mexico–Guatemala border
Authors: Carlón Allende Teodoro , Macías José Luis , Mendoza Manuel E. , Villanueva Díaz José
Published: November 2019

Volcanic activity can have a significant effect on the growth and survival of trees. The objective of our research was to analyze the effects of the 1855–1856 eruption of the Tacaná volcano and the ashfall from the 1902 eruption of the Santa María volcano, Guatemala, on the radial growth of trees at Tacaná. Dendrochronological sampling was carried out on sites covered by Pinus hartwegii Lindl., and a ring-width chronology was built using 102 increment cores from 75 trees. The ring-width chronology shows two statistically significant suppression events. One of these events occurred from 1857 to 1868 and was potentially caused by the historic eruption of Tacaná (1855–1856). The second suppression event occurred from 1903 to 1908, during which tree growth was affected 1 year after the ashfall caused by the 1902 eruption of Santa María. The growth suppression did not have the same magnitude in all sampled trees and may be related to the thickness of the ash layer deposited around each tree. For the first time, we show that tree growth at Tacaná is reduced by ashfall from volcanic eruptions. Our results may contribute to the evaluation of risks associated with the volcanic activity of the Tacaná volcano.
Traffic dynamics on two-layer multiplex networks with limited queue resource
Authors: Ma Jinlong , Wang Huiling , Ren Hao , Xu Xiangyang , Zhang Dongwen , Liu Guangyuan
Published: November 2019

Modeling multiple complex systems as multiplex networks has refreshed our opinions about the structure and dynamics of assorted real-world systems. By studying the traffic dynamics of two-layer multiplex networks, it can be found that the limited buffer queue length of each node in both the logical and physical layers is one of the factors that restrict the whole network traffic capacity. Since high degree nodes in the network may bear heavier load, it is necessary to allocate a larger buffer queue to them. In order to enhance the transport efficiency, a new queue allocation strategy is proposed to alleviate the congestion of the two-layer multiplex networks. By extensive computer simulations, the proposed strategy can effectively improve the traffic capacity of the multiplex networks.
Chiral solitons of the (1 + 2)-dimensional nonlinear Schrodinger’s equation
Authors: Javid Ahmad , Raza Nauman
Published: November 2019

In this work, dark and singular soliton solutions of the (1[Formula: see text]+[Formula: see text]2)-dimensional chiral nonlinear Schrödinger’s equation are obtained and analyzed dynamically along with graphical depictions. The extraction of these chiral solitons is carried out using two integration tools such as the modified simple equation method and the [Formula: see text]-expansion method. The validity conditions for the existence of these solitons are also retrieved. It is highlighted that the solitons retrieved here are of chiral nature.
Structural stability of nematic liquid crystal droplets in the light of the catastrophe theory
Authors: Parshin Alexander M.
Published: November 2019

Dynamical systems and defects in liquid crystals (LCs) are described using topological methods. Meanwhile, the director field distribution in LC droplets is affected by many bulk and surface factors that are difficult to take into account in the topological analysis. Therefore, the structural instability of a LC droplet formed in a magnetic field has been investigated by us in the framework of the catastrophe theory. The effect of temperature on the control parameters of the cusp catastrophe, which leads to the transition from a bipolar structure with extended poles to the homogeneous or radial configuration, has been estimated. It has been established from the potential curves that the transition is induced by the variation in the LC director orientation between the potential minima related to the LC polymer anchoring energy and magnetic field. The interplay of the cusp catastrophe control parameters and anchoring parameters has been elucidated.
Dynamics of rational solutions in a new generalized Kadomtsev–Petviashvili equation
Authors: Hosseini K. , Aligoli M. , Mirzazadeh M. , Eslami M. , Gómez-Aguilar J. F.
Published: November 2019

Rational solutions of nonlinear evolution (NLE) equations have been the subject of numerous research papers. In this paper, a new generalized Kadomtsev–Petviashvili (KP) equation with diverse applications is investigated analytically. Multiple solitons, breather and rogue waves, and complexitons as special cases of rational solutions to the new generalized KP equation are formally extracted with the help of symbolic computations. Some two- and three-dimensional figures are considered to show the dynamics of rational solutions in the new generalized KP equation.
The complexity of the equation solvability and equivalence problems over finite groups
Authors: Földvári Attila , Horváth Gábor
Published: November 2019

We provide a polynomial time algorithm for deciding the equation solvability problem over finite groups that are semidirect products of a [Formula: see text]-group and an Abelian group. As a consequence, we obtain a polynomial time algorithm for deciding the equivalence problem over semidirect products of a finite nilpotent group and a finite Abelian group. The key ingredient of the proof is to represent group expressions using a special polycyclic presentation of these finite solvable groups.
Matrix Method for Buckling Analysis of Partially Composite Layered Columns Based on Hencky Bar-Chain Model
Authors: Huang Xiaokun , Cui Mingzhe , Liu Qiang , Nie Jianguo
Published: November 2019

The buckling behavior of partially composite layered columns (PCLCs) under axial compressive load is significantly influenced by the slip at the interface of load carrying layers, which brings complexity to the analysis. In this paper, a matrix method based on the Hencky bar-chain model (HBM) is developed for the buckling analysis of PCLCs. The conventional assumption of HBM is modified to consider the interfacial slip properly. Three illustrative problems are presented to show the solving procedure of the HBM-based matrix method. The results are compared to those obtained through analytical formula or finite element method (FEM), and the applicability of the developed method in the buckling analysis of PCLCs with various sectional compositions and boundary conditions is validated. It is proved that the buckling load can be predicted accurately by the developed method. The method is easy to handle, highly adaptable and widely applicable, thus is a promising tool for the buckling analysis of PCLCs.
Finite Bending and Straightening of Hyperelastic Materials: Analytical Solution and FEM
Authors: Sheikhi Sara , Shojaeifard Mohammad , Baghani Mostafa
Published: November 2019

In this research, an incompressible, isotropic, nonlinear elastic rectangular block and a circular cylindrical sector are studied under bending and straightening moments, respectively. Analytical approaches are presented on implementing of the left Cauchy–Green tensor and Cauchy stresses. In addition, finite element analysis of both problems is carried out using UHYPER user-defined subroutine in ABAQUS to verify the analytical methods. Four different invariant-based strain energy functions, including neo-Hookean, Mooney–Rivlin, Arruda–Boyce, and recently proposed polynomial Exp-Exp models, are examined, and the results are compared. Material parameters of silicon rubber for the strain energy functions are identified by applying an optimization procedure. Finite element method results confirmed the analytical approach with great compatibility. Results showed that the length of the unbent beam does not affect the stress. Likewise, the initial angle of curved structure does not affect the unbending moment and stresses. Moreover, the Exp-Exp model had a slightly different result rather than other strain energies, which means that this model is more conservative than its counterparts. Furthermore, the Exp-Exp strain energy function is calibrated for tissue-like phantom and is compared with experimental data.
Effect of Dispersion Forces on Dynamic Stability of Electrostatically Actuated Micro/Nano-Beams in Presence of Mechanical Shocks
Authors: Hajarian Amin , Zand Mahdi Moghimi , Zolfaghari Naeem
Published: November 2019

Dispersion forces such as van der Waals and Casimir interactions become important when the size of structures shrinks. Therefore, the effective design of micro and nano-sized structures depends on appropriate consideration of these forces. In the current research, we analyzed the effect of dispersion forces on the dynamic behavior of a micro/nanobeam actuated by electrostatic forces subject to a mechanical shock. We used the Euler–Bernoulli beam theory including nonlinearities due to mid-plane stretching in our model. The equation of motion is solved using time-dependent finite element method, and pull-in forces are calculated. The stability regimes are evaluated as the set of three force parameters in which the beam elasticity overcomes the external forces, and the beam is able to vibrate without hitting the substrate. Results show that the design of the beam should be such that the three sets of non-dimensional parameters that determine the intensity of shock, dispersion, and electrostatic force do not fall above the stability limit to avoid pull-in instability. Our results have applications in the design of electrostatically actuated micro/nanobeams in mechanical shock environments such as accelerometers.
Introduction to the thematic collection: Naturally Fractured Reservoirs
Authors: Finkbeiner Thomas , Bertotti Giovanni , Geiger Sebastian
Published: November 2019

Thematic collection:
This article is part of the Naturally Fractured Reservoirs collection available at:
https://www.lyellcollection.org/cc/naturally-fractured-reservoirs
Computational quantification of patient-specific changes in ventricular dynamics associated with pulmonary hypertension
Authors: Finsberg Henrik , Xi Ce , Zhao Xiaodan , Tan Ju Le , Genet Martin , Sundnes Joakim , Lee Lik Chuan , Zhong Liang , Wall Samuel T.
Published: November 2019

Pulmonary arterial hypertension (PAH) causes an increase in the mechanical loading imposed on the right ventricle (RV) that results in progressive changes to its mechanics and function. Here, we quantify the mechanical changes associated with PAH by assimilating clinical data consisting of reconstructed three-dimensional geometry, pressure, and volume waveforms, as well as regional strains measured in patients with PAH ( n = 12) and controls ( n = 6) within a computational modeling framework of the ventricles. Modeling parameters reflecting regional passive stiffness and load-independent contractility as indexed by the tissue active tension were optimized so that simulation results matched the measurements. The optimized parameters were compared with clinical metrics to find usable indicators associated with the underlying mechanical changes. Peak contractility of the RV free wall (RVFW) γRVFW,max was found to be strongly correlated and had an inverse relationship with the RV and left ventricle (LV) end-diastolic volume ratio (i.e., RVEDV/LVEDV) (RVEDV/LVEDV)+ 0.44, R2 = 0.77). Correlation with RV ejection fraction ( R2 = 0.50) and end-diastolic volume index ( R2 = 0.40) were comparatively weaker. Patients with with RVEDV/LVEDV > 1.5 had 25% lower γRVFW,max ( P < 0.05) than that of the control. On average, RVFW passive stiffness progressively increased with the degree of remodeling as indexed by RVEDV/LVEDV. These results suggest a mechanical basis of using RVEDV/LVEDV as a clinical index for delineating disease severity and estimating RVFW contractility in patients with PAH.

NEW & NOTEWORTHY This article presents patient-specific data assimilation of a patient cohort and physical description of clinical observations.
Acute reduction in cerebral blood velocity on supine-to-stand transition increases postural instability in young adults
Authors: Fitzgibbon-Collins Laura K. , Noguchi Mamiko , Heckman George A. , Hughson Richard L. , Robertson Andrew D.
Published: November 2019

We tested the hypothesis that transient deficits in cerebral blood flow are associated with postural sway. In 19 young, healthy adults, we examined the association between the drop in cerebral blood flow during supine-to-stand transitions, indexed by transcranial Doppler ultrasound [middle cerebral artery blood velocity at diastole (MCAdv)] and near-infrared spectroscopy [tissue saturation index (TSI)] and the center of pressure displacement while standing. Participants performed transitions under three conditions aimed at progressively increasing the drop in MCAdv, in a randomized order: 1) a control transition (Con); 2) a transition that coincided with deflation of bilateral thigh cuffs; and 3) a transition that coincided with both thigh-cuff deflation and 90 s of prior hyperventilation (HTC). The deficit in diastolic blood velocity (MCAdv deficit) was quantified as the difference between MCAdv and its preceding baseline value, summed over 10 s, beginning at the MCAdv nadir. Compared with Con, HTC led to greater drops in MCAdv ( P = 0.003) and TSI ( P < 0.001) at nadir. The MCAdv deficit was positively associated with the center of pressure displacement vector-average using repeated-measures correlation (repeated-measures correlation coefficient = 0.56, P < 0.001). An a posteriori analysis identified a sub-group of participants that showed an exaggerated increase in MCAdv deficit and greater postural instability in both the anterior-posterior ( P = 0.002) and medial-lateral ( P = 0.021) directions in response to the interventions. These findings support the theory that individuals who experience greater initial cerebral hypoperfusion on standing may be at a greater risk for falls.

NEW & NOTEWORTHY Dizziness and risk for falls after standing might link directly to reduced delivery of oxygen to the brain. By introducing challenges that increased the drop in brain blood flow in healthy young adults, we have shown for the first time a direct link to greater postural instability. These results point to a need to measure cerebral blood flow and/or oxygenation after postural transitions in populations, such as older adults, to assist in fall risk assessment.
Modeling Tumor Evolutionary Dynamics to Predict Clinical Outcomes for Patients with Metastatic Colorectal Cancer: A Retrospective Analysis
Authors: Zhou Jiawei , Liu Yutong , Zhang Yubo , Li Quefeng , Cao Yanguang
Published: November 2019

Over 50% of colorectal cancer patients develop resistance after a transient response to therapy. Understanding tumor resistance from an evolutionary perspective leads to better predictions of treatment outcomes. The objectives of this study were to develop a computational framework to analyze tumor longitudinal measurements and recapitulate the individual evolutionary dynamics in metastatic colorectal cancer (mCRC) patients. A stochastic modeling framework was developed to depict the whole spectrum of tumor evolution prior to diagnosis and during and after therapy. The evolutionary model was optimized using a nonlinear mixed effect (NLME) method based on the longitudinal measurements of liver metastatic lesions from 599 mCRC patients. The deterministic limits in the NLME model were applied to optimize the stochastic model for each patient. Cox proportional hazards models coupled with the least absolute shrinkage and selection operator (LASSO) algorithm were applied to predict patients' progression-free survival (PFS) and overall survival (OS). The stochastic evolutionary model well described the longitudinal profiles of tumor sizes. The evolutionary parameters optimized for each patient indicated substantial interpatient variability. The number of resistant subclones at diagnosis was found to be a significant predictor to survival, and the hazard ratios with 95% CI were 1.09 (0.79–1.49) and 1.54 (1.01–2.34) for patients with three or more resistant subclones. Coupled with several patient characteristics, evolutionary parameters strongly predict patients' PFS and OS. A stochastic computational framework was successfully developed to recapitulate individual patient evolutionary dynamics, which could predict clinical survival outcomes in mCRC patients.

Significance:

A data analysis framework depicts the individual evolutionary dynamics of mCRC patients and can be generalized to project patient survival outcomes.
Pharmacokinetics of Nilotinib in Pediatric Patients with Philadelphia Chromosome–Positive Chronic Myeloid Leukemia or Acute Lymphoblastic Leukemia
Authors: Hijiya Nobuko , Zwaan C. Michel , Rizzari Carmelo , Foà Robin , Abbink Floor , Lancaster Donna , Landman-Parker Judith , Millot Frédéric , Moppett John , Nelken Brigitte , Caterina Putti Maria , Tian Xianbin , Sinclair Karen , Santanastasio Helene , Buchbinder Aby , Kearns Pamela
Published: November 2019

Purpose:

We investigated nilotinib exposure in pediatric patients with chronic myeloid leukemia (CML) or Philadelphia chromosome–positive (Ph+) acute lymphoblastic leukemia (ALL) resistant to, relapsed on, refractory to, or intolerant of previous treatment.

Patients and Methods:

Fifteen patients (aged 1–<18 years) with CML resistant to or intolerant of imatinib and/or dasatinib (n = 11) or Ph+ ALL relapsed on or refractory to standard therapy (n = 4) enrolled in this phase I study. Nilotinib (230 mg/m2 twice daily; equivalent to the adult 400-mg twice-daily dose) was administered orally in 12 or 24 cycles of 28 days. The primary objective was to characterize the pharmacokinetics of nilotinib in pediatric patients.

Results:

The area under the concentration–time curve at steady state was slightly lower in pediatric patients versus adults (14,751.4 vs. 17,102.9 ng/h/mL); the geometric mean ratio (GMR; pediatric:adult) was 0.86 [90% confidence interval (CI), 0.70–1.06]. Body surface area–adjusted systemic clearance was slightly higher in pediatric versus adult patients (GMR, 1.30; 90% CI, 1.04–1.62). Nilotinib was generally well tolerated. The most common adverse events were headache, vomiting, increased blood bilirubin, and rash. Three patients with CML achieved major molecular response, and three with Ph+ ALL achieved complete remission.

Conclusions:

Nilotinib 230 mg/m2 twice daily in pediatric patients provided a pharmacokinetics and safety profile comparable with the adult reference dose; clinical activity was demonstrated in both CML and Ph+ ALL. This dose is recommended for further evaluation in pediatric patients. The safety profile was consistent with that in adults.