bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of the efficiency of the Onderstepoort‐ and Centres for Disease Control ultraviolet light traps for the collection of livestock associated Culicoides species in South Africa
Authors: Venter G. J. , Sebitsang S. S. , Swart V. R. , Boikanyo S. N. B. , de Beer C. J.
Published: November 2021

Comparative monitoring of the abundance and distribution of Culicoides biting midges (Diptera: Ceratopogonidae), the biological vectors of the causative agents of several diseases of global veterinary importance, will be crucial in determining the risk of disease outbreak and spread. Ultraviolet (UV) suction traps have become the most frequent method used for the monitoring of Culicoides diversity and abundance. The current study compared the trapping efficiency of the two most used UV suction light traps, i.e., the Onderstepoort (OP)‐ and the Centres for Disease Control trap, for the collection of livestock associated Culicoides species in South Africa. The study confirmed the superiority of the OP trap and indicated a correlation in species composition and age grading results as determine with the two trap types. Substantial variations in the comparative trap efficiency, as found between areas and sites within an area, suggest that a universal conversion factor between the two trap types may not be advisable as it is unclear to what extent species composition and environmental factors may influence the conversion factor. Light traps, independent of trap model, can be considered acceptable for determining the serial comparison of population numbers for seasonal fluctuation and species abundance in distribution surveys.
Phytochrome interacting factor 3 regulates pollen mitotic division through auxin signalling and sugar metabolism pathways in tomato
Authors: Yang Dandan , Liu Yue , Ali Muhammad , Ye Lei , Pan Changtian , Li Mengzhuo , Zhao Xiaolin , Yu Fangjie , Zhao Xinai , Lu Gang
Published: November 2021

The development of viable pollen determines male fertility, and is crucial for reproduction in flowering plants. Phytochrome interacting factor 3 (PIF3) acts as a central regulator of plant growth and development, but its relationship with pollen development has not been determined.

Through genetic, histological and transcriptomic analyses, we identified an essential role for SlPIF3 in regulating tomato (Solanum lycopersicum) pollen development. Knocking out SlPIF3 using clustered regularly interspaced short palindromic repeats/CRISPR‐associated protein 9 resulted in pollen mitosis I arrest, and a failure to form viable pollen. We further demonstrated that both glutamate synthase 1 (SlGLT1) and cell wall invertase 9 (SlCWIN9), involved in auxin and sugar homeostasis, respectively, colocalised with SlPIF3 in the anthers and were directly regulated by SlPIF3. Knockout of either SlGLT1 or SlCWIN9 phenocopied the pollen phenotype of SlPIF3 knockout (Slpif3) lines.

Slpif3 fertility was partially restored by exogenous auxin indole‐3‐acetic acid in a dose‐dependent manner.

This study reveals a mechanism by which SlPIF3 regulates pollen development and highlights a new strategy for creating hormone‐regulated genic male sterile lines for tomato hybrid seed production.
Data‐Driven Newsvendor Problems Regularized by a Profit Risk Constraint
Authors: Lin Shaochong , Chen Youhua (Frank) , Li Yanzhi , Shen Zuo‐Jun Max
Published: November 2021

We study a risk‐averse newsvendor problem where demand distribution is unknown. The focal product is new, and only the historical demand information of related products is available. The newsvendor aims to maximize its expected profit subject to a profit risk constraint. We develop a model with a value‐at‐risk constraint and propose a data‐driven approximation to the theoretical risk‐averse newsvendor model. Specifically, we use machine learning methods to weight the similarity between the new product and the previous ones based on covariates. The sample‐dependent weights are then embedded to approximate the expected profit and the profit risk constraint. We show that the data‐driven risk‐averse newsvendor solution entails a closed‐form quantile structure and can be efficiently computed. Finally, we prove that this data‐driven solution is asymptotically optimal. Experiments based on real data and synthetic data demonstrate the effectiveness of our approach. We observe that under data‐driven decision‐making, the average realized profit may benefit from a stronger risk aversion, contrary to that in the theoretical risk‐averse newsvendor model. In fact, even a risk‐neutral newsvendor can benefit from incorporating a risk constraint under data‐driven decision‐making. This situation is due to the value‐at‐risk constraint that effectively plays a regularizing role (via reducing the variance of order quantities) in mitigating issues of data‐driven decision‐making, such as sampling error and model misspecification. However, the above‐mentioned effects diminish with the increase in the size of the training data set, as the asymptotic optimality result implies.
PRESENTATION OF ANUÁRIO DO INSTITUTO DE GEOCIÊNCIAS, Volume 44
Authors: Dereczynski Claudine Pereira
Published: November 2021

Abstract
Performance Analysis of a Novel Cascade Vapor Compression System for Small-Scale Desalination and Cooling
Authors: Alkhulaifi Yousif M. , Alsadah Jihad H. , Mokheimer Esmail M. A.
Published: November 2021

The demand for improving living standards has led to increasing freshwater consumption and comfort cooling, requiring significant performance improvements. In this regard, a novel and efficient cascade refrigeration system (CRS) for simultaneous generation of considerable freshwater and cooling effect is proposed. The system does not require dedicated components for desalinating seawater because it is a by-product of the proposed CRS. Utilizing the cascade configuration enhances energy efficiency by lowering the compression work while improving energy recovery by utilizing the heat rejected from the condenser of low-temperature cycle to vaporize seawater for desalination in the evaporator of the high-temperature cycle of the proposed cascade system. A mathematical model of the innovative system based on thermodynamic and economic principles has been developed and utilized to predict the proposed system's thermal performance and cost-savings. A comprehensive analysis has been conducted to study the effect of multiple parameters such as the evaporator, condenser, and brine boiling temperatures. The main studied parameters were coefficient of performance (COP), gain output ratio (GOR), freshwater production, and total cost-savings. For a 10 tons of refrigeration (TR) unit, the freshwater production was between 56.11 and 73.36 kg/h, with cost-savings reaching 2226 US$/year. It was found that the freshwater production increased with condenser and brine boiling temperature but decreased with evaporator temperature. The COP improvement can be as much as 26% over the reference cooling system without desalination.
Characterization of the Flagellar Collar Reveals Structural Plasticity Essential for Spirochete Motility
Authors: Chang Yunjie , Xu Hui , Motaleb Md A. , Liu Jun
Published: November 2021

Many spirochetes cause serious human diseases. They are well recognized by their distinct morphology and motility.
Leveraging Fungal and Human Calcineurin-Inhibitor Structures, Biophysical Data, and Dynamics To Design Selective and Nonimmunosuppressive FK506 Analogs
Authors: Gobeil Sophie M.-C. , Bobay Benjamin G. , Juvvadi Praveen R. , Cole D. Christopher , Heitman Joseph , Steinbach William J. , Venters Ronald A. , Spicer Leonard D.
Published: November 2021

Invasive fungal infections are a leading cause of death in the immunocompromised patient population. The rise in drug resistance to current antifungals highlights the urgent need to develop more efficacious and highly selective agents.
A Genetic Trap in Yeast for Inhibitors of SARS-CoV-2 Main Protease
Authors: Alalam Hanna , Sigurdardóttir Sunniva , Bourgard Catarina , Tiukova Ievgeniia , King Ross D. , Grøtli Morten , Sunnerhagen Per
Published: November 2021

The COVID-19 pandemic may continue for several years before vaccination campaigns can put an end to it globally. Thus, the need for discovery of new antiviral drug candidates will remain.
Dying with dignity: the challenges of end-of-life care in patients with substance use disorders
Authors: Datta Prasun , Kruk Jeffrey S , Jordan Kylie , Fisher Karen A
Published: November 2021

Substance use disorder is a chronic disease carrying a high risk of morbidity and mortality. We report a case of a patient on long-term opioid agonist treatment who was diagnosed with metastatic cholangiocarcinoma and was referred to palliative care services almost contemporaneously with this diagnosis. In this report, we explore the challenges posed in offering holistic care during the end of life of a patient with a history of opioid dependence. A coordinated approach by addiction medicine and palliative care teams can allow patients from this complex cohort to ultimately die with dignity.
Impact of COVID-19 on the stroke rehabilitation pathway: multidisciplinary team reflections on a patient and carer journey from acute to community stroke services
Authors: Lucas Lauren , Gordon Sophie , Heyes Ruth
Published: November 2021

A 62-year old man attended accident and emergency in June 2020 with dense right sided weakness, aphasia and confusion. Investigations revealed a left middle cerebral artery infarct, and he was admitted under the stroke team for ongoing inpatient rehabilitation. He was discharged home in September 2020 and received community stroke rehabilitation from physiotherapy, nursing, occupational therapy and speech and language therapy. He is now working towards a graded discharge from the Community Stroke and Neuro Rehab Team, after achieving his rehabilitation goals. In this case, the multidisciplinary team adopted different ways of working to accommodate the patients’ priorities while also negotiating the COVID-19 pandemic. This included taking a transdisciplinary approach to rehabilitation and considering alternative supported self-management strategies. This case highlighted several learning points, particularly the potential benefits of shared goal setting for patients with communication difficulties and transdisciplinary approaches to community stroke rehabilitation.
Diaphragmatic paralysis in COVID-19: a rare cause of postacute sequelae of COVID-19 dyspnoea
Authors: Dandawate Nupur , Humphreys Christopher , Gordan Patrick , Okin Daniel
Published: November 2021

We describe a 56-year-old female patient hospitalised with COVID-19 in April 2020 who had persistent respiratory symptoms after radiographic and microbiologic recovery. X-ray of the chest demonstrated an elevated right hemidiaphragm while fluoroscopy confirmed unilateral diaphragmatic paralysis. Symptoms resolved gradually, concurrent with restoration of right hemidiaphragm function. Thus, we describe a rare cause of postacute sequelae of COVID-19 dyspnoea.
Conjunctival ultraviolet autofluorescence area decreases with age and sunglasses use
Authors: Lingham Gareth , Kugelman Jason , Charng Jason , Lee Samantha SY , Yazar Seyhan , McKnight Charlotte M , Coroneo Minas T , Lucas Robyn M , Brown Holly , Stevenson Louis J , Mackey David A , Alonso-Caneiro David
Published: November 2021

Background

Conjunctival ultraviolet autofluorescence (CUVAF) is a method of detecting conjunctival damage related to ultraviolet radiation exposure. In cross-sectional studies, CUVAF area is positively associated with self-reported time spent outdoors and pterygium and negatively associated with myopia; however, longitudinal studies are scarce.

Aims

To use a novel deep learning-based tool to assess 8-year change in CUVAF area in young adults, investigate factors associated with this change and identify the number of new onset pterygia.

Methods

A deep learning-based CUVAF tool was developed to measure CUVAF area. CUVAF area and pterygium status were assessed at three study visits: baseline (participants were approximately 20 years old) and at 7-year and 8-year follow-ups. Participants self-reported sun protection behaviours and ocular history.

Results

CUVAF data were available for 1497 participants from at least one study visit; 633 (43%) participants had complete CUVAF data. Mean CUVAF areas at baseline and the 7-year and 8-year follow-ups were 48.4, 39.3 and 37.7 mm2, respectively. There was a decrease in mean CUVAF area over time (change in total CUVAF area=−0.96 mm2per year (95% CI: −1.07 to –0.86)). For participants who wore sunglasses ≥1/2 of the time, CUVAF area decreased by an additional −0.42 mm2per year (95% CI: −0.72 to –0.12) on average. Fourteen (1.5%) participants developed a pterygium.

Conclusions

In this young adult cohort, CUVAF area declined over an 8-year period. Wearing sunglasses was associated with a faster reduction in CUVAF area. Deep learning-based models can assist in accurate and efficient measurement of CUVAF area.
Relationship between Stress and Alexithymia, Emotional Processing and Negative/Positive Affect in Medical Staff Working amid the COVID-19 Pandemic
Authors: Warchoł-Biedermann Katarzyna , Bugajski Paweł , Budzicz Łukasz , Ziarko Michał , Jasielska Aleksandra , Samborski Włodzimierz , Daroszewski Przemysław , Greberski Krzysztof , Bączyk Grażyna , Karoń Jacek , Mojs Ewa
Published: November 2021

The psychological burden of the COVID-19 pandemic may have a lasting effect on emotional well-being of healthcare workers. Medical personnel working at the time of the pandemic may experience elevated occupational stress due to the uncontrollability of the virus, high perceived risk of infection, poor understanding of the novel virus transmission routes and unavailability of effective antiviral agents. This study used path analysis to analyze the relationship between stress and alexithymia, emotional processing and negative/positive affect in healthcare workers. The sample included 167 nurses, 65 physicians and 53 paramedics. Sixty-two (21.75 %) respondents worked in COVID-19-designated hospitals. Respondents were administered the Toronto Alexithymia Scale-20, Cohen's Perceived Stress Scale, Emotional Processing Scale, and the Positive and Negative Affect Schedule. The model showed excellent fit indices (χ2 (2)=2.642, p=0.267; CFI=0.999, RMSEA=0.034, SRMR=0.015). Multiple group path analysis demonstrated physicians differed from nurses and paramedics at the model level (X2diff (7)=14.155, p<0.05 and X2diff (7)=18.642, p<0.01, respectively). The relationship between alexithymia and emotional processing was stronger in nurses than in physicians (difference in beta=0.27; p<0.05). Individual path χ2 tests also revealed significantly different paths across these groups. The results of the study may be used to develop evidence-based intervention programs promoting healthcare workers’ mental health and well-being.
Cigarette dependence is more prevalent and increasing among US adolescents and adults who use cannabis, 2002–2019
Authors: Weinberger Andrea H , Dierker Lisa , Zhu Jiaqi , Levin Jacob , Goodwin Renee D
Published: November 2021

Significance

Cannabis use is increasing among cigarette smokers. If cannabis use is associated with cigarette dependence, a barrier to smoking cessation, this could have public health implications for tobacco control. The current study estimated the prevalence of cigarette dependence among US individuals who smoke cigarettes by cannabis use status, and investigated trends in cigarette dependence from 2002 to 2019 among cigarette smokers by cannabis use status and cigarette consumption (ie, cigarettes per day, CPD).

Methods

Data were drawn from the 2002–2019 annual National Survey on Drug Use and Health and included US individuals aged 12+ years who used cigarettes at least once in the past month (n=231 572). Logistic regression was used to estimate the prevalence of cigarette dependence, measured as time to first cigarette <30 min, by past-month cannabis use (no use, non-daily use, daily use), and to estimate trends in cigarette dependence from 2002 to 2019 overall and stratified by cannabis use and smoking level (light, 1–5 CPD; moderate, 6–15 CPD; heavy, 16+ CPD).

Results

Across all levels of cigarette use, cigarette dependence was significantly more common among individuals with daily cannabis use compared with those with non-daily or no cannabis use. From 2002 to 2019, cigarette dependence increased among cigarette smokers with non-daily cannabis use, and among light and moderate cigarette smokers with no cannabis use.

Conclusions

US individuals who use both cigarettes and cannabis report a higher prevalence of cigarette dependence relative to individuals who use cigarettes and do not use cannabis at virtually all levels of cigarette consumption. Further, cigarette dependence is increasing in the USA both among those who use and do not use cannabis. Given the increase in cannabis use among those using cigarettes, efforts to elucidate the nature of the association between cannabis and cigarette dependence are needed.
Genetic variation in westslope cutthroat trout reveals that widespread genetic rescue is warranted
Authors: Kovach Ryan P. , Leary Robb F. , Bell Donovan A. , Painter Sally , Lodmell Angela , Whiteley Andrew R.
Published: November 2021

Although human fragmentation of freshwater habitats is ubiquitous, the genetic consequences of isolation and a roadmap to address them are poorly documented for most fishes. This is unfortunate, because translocation for genetic rescue could help mitigate problems. We used genetic data (32 SNPs) from 203 populations of westslope cutthroat trout (Oncorhynchus clarkii lewisi) to (1) document the effect of fragmentation on genetic variation and population structure, (2) identify candidate populations for genetic rescue, and (3) quantify the potential benefits of strategic translocation efforts. Human-isolated populations had substantially lower genetic variation and elevated genetic differentiation, indicating that many populations are strongly influenced by random genetic drift. Based on simple criteria, 23 populations were candidates for genetic rescue, which represented a majority (51%) of suitable populations in one major region (Missouri drainage). Population genetic theory suggests that translocation of a small number of individuals (∼5 adults) from nearby populations could dramatically increase heterozygosity by up to 58% (average across populations). This effort provides a clear template for future conservation of westslope cutthroat trout, while simultaneously highlighting the potential need for similar efforts in many freshwater species.
Nullcone dual worldsheets and caustics of spacelike fronts in null de Sitter sphere
Authors: Song Xue , Pei Donghe
Published: November 2021

In physics, the application of the regular cases of spacelike fronts has been studied extensively; however, under the gravitational influence, the spacelike fronts can be singular. In this paper, we will consider the traveling trajectories of a set of parallel light rays as spacelike fronts with singularities in null de Sitter sphere. It is of great significance to investigate and explore the spacelike fronts which may have singularities in null de Sitter sphere. We also characterize the singularities of the nullcone dual worldsheets generated by spacelike fronts via the spherical curvature. Then we define the nullcone caustics and analyze the geometric properties of the nullcone caustics at singular points. Moreover, we establish the dual relationship between spacelike fronts and the nullcone dual worldsheets.
Bifurcation of Dividing Surfaces Constructed from a Pitchfork Bifurcation of Periodic Orbits in a Symmetric Potential Energy Surface with a Post-Transition-State Bifurcation
Authors: Katsanikas M. , Agaoglou M. , Wiggins S.
Published: November 2021

In this work, we analyze the bifurcation of dividing surfaces that occurs as a result of a pitchfork bifurcation of periodic orbits in a two degrees of freedom Hamiltonian System. The potential energy surface of the system that we consider has four critical points: two minima, a high energy saddle and a lower energy saddle separating two wells (minima). In this paper, we study the structure, the range, and the minimum and maximum extent of the periodic orbit dividing surfaces of the family of periodic orbits of the lower saddle as a function of the total energy.
Stability and Hopf Bifurcation Analysis of a Delayed Innovation Diffusion Model with Intra-Specific Competition
Authors: Kumar Rakesh , Sharma Anuj Kumar
Published: November 2021

This article is concerned with the diffusion of a sport in a region, and the innovation diffusion model comprising of population classes, viz. nonadopters class, information class and adopters class. A qualitative analysis is carried out to assess the global asymptotic stability of the interior equilibrium for null delay. It has also been proved that the parameter [Formula: see text] (age gaps among sportspersons) in the intra-specific competition between the new players and the senior players can even destabilize the otherwise globally stable interior equilibrium state and the coexistence of all the populations is possible through periodic solutions due to Hopf bifurcation. With the help of normal form theory and center manifold arguments, the stability of bifurcating periodic orbits is determined. Numerical simulations have been executed in support of the analytical findings.
Influence of the Fear Effect on a Holling Type II Prey–Predator System with a Michaelis–Menten Type Harvesting
Authors: Xie Binfeng , Zhang Zhengce , Zhang Na
Published: November 2021

In this work, a prey–predator system with Holling type II response function including a Michaelis–Menten type capture and fear effect is put forward to be studied. Firstly, the existence and stability of equilibria of the system are discussed. Then, by considering the harvesting coefficient as bifurcation parameter, the occurrence of Hopf bifurcation at the positive equilibrium point and the existence of limit cycle emerging through Hopf bifurcation are proved. Furthermore, through the analysis of fear effect and capture item, we find that: (i) the fear effect can either stabilize the system by excluding periodic solutions or destroy the stability of the system and produce periodic oscillation behavior; (ii) increasing the level of fear can reduce the final number of predators, but not lead to extinction; (iii) the harvesting coefficient also has significant influence on the persistence of the predator. Finally, numerical simulations are presented to illustrate the results.
Linear Li–Yorke Chaos in a Finite-Dimensional Space with Weak Topology
Authors: Zhang Xu , Chen Guanrong
Published: November 2021

It is well known that a finite-dimensional linear system cannot be chaotic. In this article, by introducing a weak topology into a two-dimensional Euclidean space, it shows that Li–Yorke chaos can be generated by a linear map, where the weak topology is induced by a linear functional. Some examples of linear systems are presented, some are chaotic while some others regular. Consequently, several open problems are posted.
A NONLINEAR STRAIN-DEPENDENT VARIABLE-ORDER FRACTIONAL MODEL WITH APPLICATIONS TO ALUMINUM FOAMS
Authors: CAI WEI , WANG PING
Published: November 2021

In this paper, a power-law strain-dependent variable order is first incorporated into the fractional constitutive model and employed to describe mechanical behaviors of aluminum foams under quasi-static compression and tension. Comparative results illustrate that power-law strain-dependent variable order is capable of better describing stress–strain responses compared with the traditional linear one. The evolution of fractional order along with the porosities or relative densities can be well qualitatively interpreted by its physical meaning. Furthermore, the model is also extended to characterize the impact behaviors under large constant strain rates. It is observed that fractional model with sinusoidal variable order agrees well with the experimental data of aluminum foams with impact and non-impact surfaces.
Productive Capacities, Economic Growth and Economic Growth Volatility in Developing Countries: Does Structural Economic Vulnerability Matter?
Authors: Gnangnon Sena Kimm
Published: November 2021

Recent years’ global shocks (e.g., the 2008 financial crisis and the COVID-19 pandemic) and environmental shocks — such as natural disasters — have heightened the vulnerability of developing countries to future shocks, and can compromise their development prospects. International institutions and researchers have advocated that the strengthening of productive capacities in these countries would help enhance the resilience of their economies to shocks, and promote sustainable development. This paper has examined the effect of productive capacities on economic growth and economic growth volatility in developing countries, in particular when they face a high level of structural economic vulnerability. The analysis covers 117 developing countries over the period of 2000–2018. It shows that productive capacities not only promote economic growth, but also reduce economic growth volatility. On the other hand, structural economic vulnerability reduces economic growth (in particular when it exceeds a certain level), and induces greater volatility of economic growth. Interestingly, productive capacities promote economic growth and reduce economic growth volatility in countries that face a high degree of structural economic vulnerability. These findings support the recommendation by international institutions and researchers that if they were to enhance the resilience of their economies to shocks, and promote sustainable economic growth, developing countries (in particular the poorest ones) should strengthen their productive capacities.
First-principles study on controlling transport gap of graphene nanoribbons using hybrid Armchair–Zigzag nanostructures
Authors: Cuong Nguyen Tien
Published: November 2021

The electronic and transport properties of hybrid armchair–zigzag nanostructures, which include right-angles-shaped GNRs, U-shaped GNRs, and patterned nanopores structured GRNs, were studied by the combination of density functional theory and nonequilibrium Green’s function method. The density of state, electron transmission spectra, and molecular orbitals were analyzed. The obtained results show that right-angles-shaped GNRs junctions tend to open a transport gap when the numbers of right-angles are greater than or equal to 4. The gap increases insignificantly as the numbers of right-angles are greater than 4. It implies that the U-shaped GNR junction, corresponding to 4 right-angles structure, is a potential structure for controlling transport gap of GRNs. The transport gap of the U-shaped GNRs decreases as the length of horizontal edge increases. In contrast, the transport gap increases as the high of vertical edge increases. In addition, the patterned nanopore had an enormous influence on the electronic and transport properties though the armchair GNRs junctions, depending on the shape and size of nanopore. This research suggests that designed tailored GNRs based on hybrid armchair–zigzag nanostructures can be used to control the transport gap of graphene. The formation of quasi-bound states at zigzag edges of the hybrid nanostructures plays a key role.
All post-Cambrian ichnospecies of
Psammichnites
Torell, 1870 belong to
Olivellites
Fenton and Fenton, 1937
b
Authors: Pazos Pablo J. , Gutiérrez Carolina
Published: November 2021

The ichnogenus
Psammichnites
herein restricted to
Psammichnites gigas
is based on comparison of morphology, feeding behaviour, contrast between the burrows and the host rock and possible producers. The record of siphonal activity as a ‘snorkel device’ is discussed. The diagnosis of the ichnogenus
Olivellites
now is amended and includes all the records of
Psammichnites
in the post-Cambrian.
Olivellites
is now documented in successions other than the classical tidal flat facies of the Carboniferous of the USA. We propose that the producer of
Olivellites
was an animal with capacity for displacement to different shallow infaunal levels for different feeding strategies. An interpretation of detritus feeding behaviour with sediment displacement (pasichnia) is favoured here. The producer of
Olivellites
was likely a bivalved mollusc that evolved after the Late Ordovician mass extinction. It was euryhaline and lived in a broad bathymetric range, and is recorded in temperate to glacially related successions. The material of
Olivellites implexus
from western Argentina is the youngest record of the ichnogenus from Western Gondwana.
Dactyloidites ottoi
(Geinitz, 1849) in Bahamian Pleistocene carbonates: a shallowest-marine indicator
Authors: Curran H. Allen , Glumac Bosiljka
Published: November 2021

The rosetted trace fossil
Dactyloidites ottoi
(
Geinitz, 1849
) is reported and described for the first time from late Pleistocene (MIS 5e) carbonates of the Bahama Archipelago in shallowing-upward, shelly calcarenites from Great Inagua and Great and Little Exuma islands. The distinctive, fan-shaped
D. ottoi
specimens from the Bahamas, while not preserved in fine detail and not revealing a shaft, compare favourably in shape and size with specimens from other localities around the world, including the oldest well-documented specimens from the Jurassic of Argentina.
D. ottoi
is interpreted as a fodinichnion formed by the activity of a deposit-feeding worm, probably a polychaete, consuming marine-plant remains within host sediment. The late Pleistocene palaeodepositional environment of these carbonate sediments is interpreted as within the lower foreshore–upper shoreface zone in full marine, tropical waters. This discovery of
D. ottoi
marks an addition to the Bahamian shallow-marine ichnocoenose within the Skolithos ichnofacies.
A Survey on Privacy Preservation in Fog-Enabled Internet of Things
Authors: Sarwar Kinza , Yongchareon Sira , Yu Jian , Ur Rehman Saeed
Published: November 2021

Despite the rapid growth and advancement in theInternet of Things (IoT), there are critical challenges that need to be addressed before the full adoption of the IoT. Data privacy is one of the hurdles towards the adoption of IoT as there might be potential misuse of users’ data and their identity in IoT applications. Several researchers have proposed different approaches to reduce privacy risks. However, most of the existing solutions still suffer from various drawbacks, such as huge bandwidth utilization and network latency, heavyweight cryptosystems, and policies that are applied on sensor devices and in the cloud. To address these issues, fog computing has been introduced for IoT network edges providing low latency, computation, and storage services. In this survey, we comprehensively review and classify privacy requirements for an in-depth understanding of privacy implications in IoT applications. Based on the classification, we highlight ongoing research efforts and limitations of the existing privacy-preservation techniques and map the existing IoT schemes with Fog-enabled IoT schemes to elaborate on the benefits and improvements that Fog-enabled IoT can bring to preserve data privacy in IoT applications. Lastly, we enumerate key research challenges and point out future research directions.
Secure Selections on Encrypted Multi-writer Streams
Authors: Perillo Angelo Massimo , Persiano Giuseppe , Trombetta Alberto
Published: November 2021

Performing searches over encrypted data is a very current and active area. Several efficient solutions have been provided for the
single-writer
scenario in which all sensitive data originate with one party (the
Data Owner
) that encrypts and uploads the data to a public repository. Subsequently, the Data Owner accesses the encrypted data through a
Query Processor
, which has direct access to the public encrypted repository. Motivated by the recent trend in pervasive data collection, we depart from this model and consider a
multi-writer
scenario in which the data originate with several and mutually untrusted parties, the
Data Sources
. In this new scenario, the Data Owner provides public parameters so that each Data Source can add encrypted items to the public encrypted stream; moreover, the Data Owner keeps some related secret information needed to generate
tokens
so that different
Query Sources
can decrypt different subsets of the encrypted stream, as specified by corresponding access policies.

We propose security model for this problem that we call
Secure Selective Stream
(
SSS
) and give a secure construction for it based on hard problems in Pairing-Based Cryptography. The cryptographic core of our construction is a new primitive,
Amortized Orthogonality Encryption
, that is crucial for the efficiency of the proposed implementation for
SSS
.
DNA End Resection: Mechanism and Control
Authors: Cejka Petr , Symington Lorraine S.
Published: November 2021

DNA double-strand breaks (DSBs) are cytotoxic lesions that threaten genome integrity and cell viability. Typically, cells repair DSBs by either nonhomologous end joining (NHEJ) or homologous recombination (HR). The relative use of these two pathways depends on many factors, including cell cycle stage and the nature of the DNA ends. A critical determinant of repair pathway selection is the initiation of 5′→3′ nucleolytic degradation of DNA ends, a process referred to as DNA end resection. End resection is essential to create single-stranded DNA overhangs, which serve as the substrate for the Rad51 recombinase to initiate HR and are refractory to NHEJ repair. Here, we review recent insights into the mechanisms of end resection, how it is regulated, and the pathological consequences of its dysregulation.
Variation and Evolution of Human Centromeres: A Field Guide and Perspective
Authors: Miga Karen H. , Alexandrov Ivan A.
Published: November 2021

We are entering a new era in genomics where entire centromeric regions are accurately represented in human reference assemblies. Access to these high-resolution maps will enable new surveys of sequence and epigenetic variation in the population and offer new insight into satellite array genomics and centromere function. Here, we focus on the sequence organization and evolution of alpha satellites, which are credited as the genetic and genomic definition of human centromeres due to their interaction with inner kinetochore proteins and their importance in the development of human artificial chromosome assays. We provide an overview of alpha satellite repeat structure and array organization in the context of these high-quality reference data sets; discuss the emergence of variation-based surveys; and provide perspective on the role of this new source of genetic and epigenetic variation in the context of chromosome biology, genome instability, and human disease.
Fatty Liver Disease: Diagnosis and Stratification
Authors: Saiman Yedidya , Duarte-Rojo Andres , Rinella Mary E.
Published: November 2021

Nonalcoholic fatty liver disease (NAFLD) is a major public health crisis affecting approximately 25% of the world's population. The spectrum of NAFLD ranges from bland steatosis to steatohepatitis with fibrosis; eventual development of cirrhosis in a subgroup of patients now represents the leading indication for liver transplant in women and in individuals older than 65. The development of noninvasive liver disease assessment tools has led to substantial progress in the diagnosis of NAFLD. Patients with NAFLD are at increased risk of cardiometabolic disease, which should therefore be an important part of the therapeutic approach. This review focuses on diagnosis and risk stratification of NAFLD across the full spectrum of disease, including important considerations in the approach to patients with cirrhosis.
Engineering β Cell Replacement Therapies for Type 1 Diabetes: Biomaterial Advances and Considerations for Macroscale Constructs
Authors: Quizon Michelle J. , García Andrés J.
Published: November 2021

While significant progress has been made in treatments for type 1 diabetes (T1D) based on exogenous insulin, transplantation of insulin-producing cells (islets or stem cell–derived β cells) remains a promising curative strategy. The current paradigm for T1D cell therapy is clinical islet transplantation (CIT)—the infusion of islets into the liver—although this therapeutic modality comes with its own limitations that deteriorate islet health. Biomaterials can be leveraged to actively address the limitations of CIT, including undesired host inflammatory and immune responses, lack of vascularization, hypoxia, and the absence of native islet extracellular matrix cues. Moreover, in efforts toward a clinically translatable T1D cell therapy, much research now focuses on developing biomaterial platforms at the macroscale, at which implanted platforms can be easily retrieved and monitored. In this review, we discuss how biomaterials have recently been harnessed for macroscale T1D β cell replacement therapies.
On the Origin of Reversible and Irreversible Reactions in LiNixCo(1−x)/2Mn(1−x)/2O2
Authors: Kleiner Karin , Murray Claire A. , Grosu Cristina , Ying Bixian , Winter Martin , Nagel Peter , Schuppler Stefan , Merz Michael
Published: November 2021

Bond formation and breakage is crucial upon energy storage in lithium transition metal oxides (LiMeO2, Me = Ni, Co, Mn), i.e., the conventional cathode materials in Li ion batteries. Near-edge X-ray absorption finestructure spectroscopy (NEXAFS) of the Me L and O K edge performed upon the first discharge of LiNixCo(1−x)/2Mn(1−x)/2O2 (x = 0.33: NCM111, x = 0.6: NCM622, x = 0.8: NCM811) in combination with charge transfer multiplet (CTM) calculations provide unambiguous evidence that redox reactions in NCMs proceed via a reversible oxidation of Ni associated with the formation of covalent bonds to O neighbors, and not, as widely assumed, via pure cationic or more recently discussed, pure anionic redox processes. Correlating these electronic changes with crystallographic data using operando synchrotron X-ray powder diffraction (SXPD) shows that the amount of ionic Ni limits the reversible capacity— at states of charge where all ionic Ni is oxidized (above 155 mAh g−1), the lattice parameters collapse, and irreversible reactions are observed. Yet the covalence of the Ni–O bonds also triggers the electronic structure and thus the operation potential of the cathodes.
Tungsten Infused Grain Boundaries Enabling Universal Performance Enhancement of Co-Free Ni-Rich Cathode Materials
Authors: Rathore Divya , Geng Chenxi , Zaker Nafiseh , Hamam Ines , Liu Yulong , Xiao Penghao , Botton Gianluigi A. , Dahn Jeff , Yang Chongyin
Published: November 2021

Ni-rich cathode materials suffer from poor capacity retention due to micro-cracking and interfacial reactivity with electrolyte. Addition of tungsten (W) to some Ni-rich materials can improve capacity retention. Here, a WO3 surface coating is applied on Ni-rich hydroxide precursors before heating with lithium hydroxide. After heating in oxygen, Ni-rich materials with any of the commonly used dopants (magnesium, aluminum, manganese, etc.) show a “universal” improvement in capacity retention. Experimental characterization and theoretical modelling showed W was concentrated in the grain boundaries between the primary grains of secondary particles of the layered oxides, and W is incorporated in amorphous LixWyOz phases rather than as a substituent in the LiNiO2 lattice. This self-infusion of W in the grain boundaries during synthesis also significantly restricts primary crystallite grain growth. Along with smaller primary grain size, the LixWyOz phases in the grain boundaries lead to improved resistance to microcracking and reduced surface or interfacial reactivity. Improving the intrinsic properties of primary grains through doping of Mg, Al, or Mn and reinforcing the secondary particle structure mechanically and chemically using W or a similar element, M, that forms LixMOy phases and does not substitute into LiNiO2 is a universal strategy to improve polycrystalline Ni-rich materials.
Analysis on Thermal Runaway Behavior of Prismatic Lithium-Ion Batteries with Autoclave Calorimetry
Authors: Hoelle S. , Scharner S. , Asanin S. , Hinrichsen O.
Published: November 2021

A total number of 25 different types of prismatic lithium-ion cells with a capacity between 8 and 145 Ah are examined in an autoclave calorimetry experiment in order to analyze their behavior during thermal runaway (TR). The safety relevant parameters such as mass loss, venting gas production and heat generation during TR are determined in two experiments per cell type and the results are compared to literature. An approximately linear dependency of the three parameters on the cell capacity is observed and hence correlations are derived. Due to the wide range in cell properties the correlations can be used as input for simulations as well as to predict the behavior of future battery cells within the property range of those tested and therefore contribute to the design of a safer battery pack.
An Improved Louvain Algorithm for Community Detection
Authors: Zhang Jicun , Fei Jiyou , Song Xueping , Feng Jiawei
Published: November 2021

Social network analysis has important research significance in sociology, business analysis, public security, and other fields. The traditional Louvain algorithm is a fast community detection algorithm with reliable results. The scale of complex networks is expanding larger all the time, and the efficiency of the Louvain algorithm will become lower. To improve the detection efficiency of large-scale networks, an improved Fast Louvain algorithm is proposed. The algorithm optimizes the iterative logic from the cyclic iteration to dynamic iteration, which speeds up the convergence speed and splits the local tree structure in the network. The split network is divided iteratively, then the tree structure is added to the partition results, and the results are optimized to reduce the computation. It has higher community aggregation, and the effect of community detection is improved. Through the experimental test of several groups of data, the Fast Louvain algorithm is superior to the traditional Louvain algorithm in partition effect and operation efficiency.
Study on Optimization of Delay Method of Wedge Cut Blasting in Tunnel
Authors: Gao Wenle , Liu Zhicheng , Wang Yanping , Yan Zhenwei , Zhang Zehua
Published: November 2021

Relying on the entrance section of a high‐speed railway tunnel blasting project, the fluid‐solid coupling algorithm based on ANSYS/LS‐DYNA was used to optimize the parameters of wedge cut blasting, and the vibration could be reduced on the basis of ensuring the blasting effect. Through the combination of visual numerical simulation results and rock‐breaking mechanism of wedge cut blasting, the maximum vibration velocity of different monitoring points in the model under different segmented time delay was analyzed. The results show that the best method for detonation is dividing the blastholes into three segments from upper to lower and dividing the left and right symmetrical blastholes into one segment. When the delay time is 10 ms, the average vibration reduction ratio is the best, which is reduced by 18% compared with the six‐hole simultaneous blasting. In addition, the actual surrounding rock stress has a clamping effect on the cut blasting area. The wedge cut blasting footage obtained by numerical simulation was basically consistent with the field results, which proved that the model is reasonable and effective. This study intuitively and accurately demonstrated the process of cut blasting, the superposition curve of vibration velocity and the vibration reduction results under different delay times, and the effect of cut blasting. The results can be directly applied to similar projects, and the optimal blasting parameters and related issues can be solved more accurately with the help of this engineering analysis method.
Secure Message Transmission for V2V Based on Mutual Authentication for VANETs
Authors: Mahmood Jabar , Duan Zongtao , Xue Heng , Yang Yun , Berwo Michael Abebe , Khan Sajjad Ahmad , Yassin Abd al Kader Ahmed
Published: November 2021

The advancements in Vehicular Ad Hoc Networks (VANETs) require more intelligent security protocols that ultimately provide unbreakable security to vehicles and other components of VANETs. VANETs face various types of security pitfalls due to the openness characteristics of the VANET communication infrastructure. Researchers have recently proposed different mutual authentication schemes that address security and privacy issues in vehicle‐to‐vehicle (V2V) communication. However, some V2V security schemes suffer from inadequate design and are hard to implement practically. In addition, some schemes face vehicle traceability and lack anonymity. Hence, this paper’s primary goal is to enhance privacy preservation through mutual authentication and to achieve better security and performance. Therefore, this article first describes the vulnerabilities of a very recent authentication scheme presented by Vasudev et al. Our analysis proves that the design of Vasudev et al.’s scheme is incorrect, and resultantly, the scheme does not provide mutual authentication between a vehicle and vehicle server when multiple vehicles are registered with the vehicle sever. Furthermore, this paper proposes a secure message transmission scheme for V2V in VANETs. The proposed scheme fulfills the security and performance requirements of VANETs. The security analysis of the proposed scheme using formal BAN and informal discussion on security features confirm that the proposed scheme fulfills the security requirements, and the performance comparisons show that the proposed scheme copes with the lightweightness requirements of VANETs.
An Improved Blade Vibration Parameter Identification Method considering Tip Clearance Variation
Authors: Zhang Liang , Wang Qidi , Li Xin
Published: November 2021

Blade tip timing (BTT) technology is the most effective means for real‐time monitoring of blade vibration. Accurately extracting the time of blade tip reaching the sensors is the key to ensure the accuracy of the BTT system. The tip clearance changes due to various complex forces during high‐speed rotation. The traditional BTT signal extraction method does not consider the influence of tip clearance change on timing accuracy and introduces large timing errors. To solve this problem, a quadratic curve fitting timing method was proposed. In addition, based on the measurement principle of the eddy current sensors, the relationship among the output voltage of the eddy current sensor, tip clearance, and the blade cutting magnetic line angle was calibrated. A multisensor vibration parameter identification algorithm based on arbitrary angular distribution was introduced. Finally, the experiments were conducted to prove the effectiveness of the proposed method. The results show that in the range of 0.4 to 1.05 mm tip clearance change, the maximum absolute error of the timing values calculated by the proposed method is 26.0359 us, which is much lower than the calculated error of 203.7459 us when using the traditional timing method. When the tip clearance changed, the constant speed synchronous vibration parameters of No. 0 blade were identified. The average value of the vibration amplitude is 1.0881 mm. Compared with the identification results without changing tip clearance, the average value error of the vibration amplitude is 0.0017 mm. It is proved that within the blade tip clearance variation of 0.4 to 0.9 mm, the timing values obtained by the proposed timing method can accurately identify the vibration parameters of the blade.