bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Realization of Python Professional English Translator
Authors: Yang Wenge , Zhao Xue
Published: April 2021

The main purpose of professional English translator is to translate more ambiguity and more professional words and sentences to meet the needs of the work. This article combines web crawler based on Python language, and analyzes Python programming and online crawler implementation. This article uses this as a basis to study how to design a professional English translator, and study the structure, business workflow, and functions of the translator. The test results prove that the designed program can effectively realize the crawler function, so that it can obtain a large amount of consistent data in a very short time, and return these related data to the user through the interface connection design. This can not only meet the needs of users for quick translation and search of English words and sentences, but also meet the needs of actual work.
The Rainfall and Meteorological Data Mining Model Based on Multi-Dimensional Precipitation Time Series
Authors: Ding Sizhe
Published: April 2021

In order to study the relationship between rainfall and related meteorological elements in rainy weather, find out the changes of related meteorological elements before and after rainfall, a multi-dimensional time series data mining model is proposed. The model first performs dimension selection pre-processing on the time series of meteorological elements to remove irrelevant and redundant dimensions, then uses the proposed extreme slope piecewise linear fitting method to segment the time series, data compression and eigenvalue extraction, and finally uses k-means clustering algorithm to symbolize the processed multi-dimensional sequence, and uses rules to extract the rainfall weather model. Experimental results show that the model has good practical value.
Research on the technology of preventing illegal terminal access
Authors: Shu ZhiMeng , Liu YongGuang , Wang HuiNan , Sun ChaoLiang , He ShanShan
Published: April 2021

As an important part of energy Internet construction, power consumption information acquisition system, as the “total entrance of power information data acquisition and the total exit of control instruction execution”, plays an increasingly important role in the safe and stable operation of the system. At present, the on-site access equipment is diversified, but there is a lack of unified active security defense early warning module, and there is no perfect security monitoring system. There are security risks such as illegal replacement of on-site terminals and private upgrade of terminals. In order to further improve the security and stability of smart grid operation, this paper makes an in-depth study on the existing security problems of the acquisition terminal and the online security monitoring of the acquisition terminal, and adopts the device fingerprint technology and password technology to meet the needs of the security protection of the acquisition terminal.
Improved ORB matching algorithm based on adaptive threshold
Authors: Li Shiji , Wang Qing , Li Jiayue
Published: April 2021

Aiming at the problem of ORB feature matching algorithm extracting background pixels as feature points and matching wrong feature points in a complex background environment, an improved ORB algorithm based on adaptive threshold is proposed, and GMS algorithm is used to screen out mismatches in the feature matching stage. First, the algorithm calculates the mean and standard deviation of the image to be matched and the reference image. Then it inputs the obtained data into the adaptive threshold calculation stage to obtain the adaptive threshold. Finally it inputs the adaptive threshold into the feature extraction and matching stage. The experimental results show that the improved ORB algorithm reduces the number of features extracted from the background of the exhibits in the complex environment of the museum, and the matching algorithm combined with the ORB algorithm and GMS increases the correct matching on the basis of slightly shorter time than the original algorithm. The algorithm has strong robustness and real-time performance.
Study on Molten Salt Corrosion Behavior of Several Stainless Steel Alloys
Authors: Men Dandan , Xiong Jian , Peng Wenyi , Bai Lingyun
Published: April 2021

Molten salt corrosion tests were performed on several stainless steels, which were 622,316, A59,625, 686,2#825,3#825 and M400. After corrosion at 680°C for 120 h, the sequence of alloys’ mass loss was 625<3#825<A59<622< 2#825<316<686<M400. SEM/EDS analysis was used to observe the surface and cross-section morphologies of the corroded samples. The alloys with high molten salt corrosion resistance formed Cr2O3 oxide layers on the surfaces of the samples, the formation of TiO2 could also enhance the corrosion resistance. However, Mn element was harmful to the alloys used in chlorine induced corrosion environment.
Research of release characteristics of ship attached fouling
Authors: Hu Xiaodong , Liu Xiaotong , Zong Dandan , Dong Shiyun
Published: April 2021

Marine fouling increases navigation resistance and restricts the performance of hulls. Based on the fluid-structure coupling theory, the release characteristics of fouling barnacles attached to the silicone coating were studied by a numerical analysis method according to the antifouling performance parameters, such as coating thickness and elastic modulus. The simulation results show that the influence of coating thickness and elastic modulus on barnacle release is far less than that of composite variable (E/T)0.5. For the hull coating with a small (E/T)0.5 value, the barnacle more easily peels off under small external forces. This provides a reference for the selection of silicone antifouling coatings for ships.
Finite element analysis of flexural performance of self-compacting recycled concrete beams with FRP slag
Authors: Liu Yi , Pei Changchun
Published: April 2021

In order to use glass powder steel slag recycled concrete in building structures, improve the recycling rate of industrial waste, and reduce environmental pollution, this paper replaces part of cement with glass powder and steel slag instead of some fine aggregates. The effect of glass powder steel slag is studied by ANSYS finite element simulation. Influence of self-compacting recycled concrete beams on flexural performance. The research result suggested: at the initial stage of cracking, the mid-span moment and mid-span deflection of C1, C2 and C3 groups of beams constructed with recycled concrete incorporating milled glass and steel slag were significantly improved compared with those of baseline group of beams and with increasing steel slag, their mid-span moment was not much changed but mid-span deflection was increased; at the yield stage, the mid-span moment and mid-span deflection of C1, C2 and C3 groups of beams constructed with recycled concrete incorporating milled glass and steel slag were significantly improved compared with those of baseline group of beams and were further increased with increasing steel slag. In this paper, the bending performance of the beam is best when 20% glass powder is used instead of cement and 80% steel slag is used instead of fine aggregate.
Experimental Study on Early Drying Shrinkage of Self-compacting Barite Concrete
Authors: Shi Jianjun , Li Qi , Zhang Zhiheng , Liu Hualiang , Yang Xiaofeng , Zhang Zhijun , Li Zhujing , Yan Wei
Published: April 2021

In this paper, raw materials such as fly ash-S95 grade mineral powder composite mineral admixture, barite coarse and fine aggregate and polycarboxylic acid water reducer are selected to successfully formulate C30 self-compacting barite concrete with good performance. It also analyzes the development law of early drying shrinkage of self-compacting barite concrete with age, and discusses the effects of fly ash and slag mixing ratio and water reducer content on concrete work, compressive strength and early drying shrinkage. The results show that: the drying shrinkage of self-compacting barite concrete develops rapidly within 1 day of age, and the drying shrinkage rate at 1 day accounts for 50% to 66% of that at 7 days of age, and then the growth trend is slow; as the proportion of fly ash increases, the performance of the concrete mixture improves. While the strength of concrete decreases in the early and mid-term, the strength gradually increases in the later period, and the shrinkage strain of concrete in the early stage also increases significantly; the proper amount of water-reducing agent can greatly improve the fluidity of the mixture. In the dosage range of 1.2%~1.4%, with the increase of the amount of water reducing agent, the compressive strength first increases and then decreases, reaching the maximum when the dosage is 1.3%, and the early drying shrinkage strain of concrete increases slightly.
A Special Thermal Fatigue Failure Mode of Pipe in Nuclear Power Plant and Its Countermeasures
Authors: Yin Qin , Feng Huixing , Xue Donglin , Shu Guo
Published: April 2021

Thermal fatigue phenomenon is well known and feedbacked in the nuclear power industry. Targeted screening principles has been developed and applied. However, a thermal fatigue failure, “Swirl Penetration” of small-diameter pipeline, was identified through a Reactor Coolant System (RCS) leakage in a nuclear power plant. Unexpectedly, this failure is not within the scope of previous screening principles of thermal fatigue. It is characterized in that the high-temperature main piping is connected downward with a certain length of vertical small-diameter piping, and then the vertical piping turns horizontally through an elbow. The reactor coolant in the lower pipeline does not flow under normal operation conditions. Subject to long-term cyclic thermal fatigue, cracks initiate and propagate in the elbow. Through researches, corrective measures are put forward to prevent, mitigate or discover it.
Focusing neutron guide design for Engineering Materials Diffractometer at CSNS
Authors: Zhan X. , Gao J. , Ma Y. , Gong Z. , Wang C. , Zhang P. , Yang H. , Hu C. , Zhou L. , Zhang S.
Published: April 2021

Engineering Materials Diffractometer (EMD) is included in
Project Phase Two of the China Spallation Neutron Source (CSNS),
which focuses on strain scanning, thermomechanical investigation and
phase transformation analysis under different sample environments,
as well as other novel industrial research for engineering
materials. After a comprehensive analysis and optimization, the
total length of EMD is designed to be 51.5 m where the primary and
secondary flight path are 49.5 m and 2 m, respectively. The
neutron optical components mainly consist of insert guides, curved
guides, bandwidth choppers, straight guides (including both straight
and focusing sections), slits, collimators, detectors, etc. Particularly, an individual 9 m logarithmic spiral focusing guide
to optimize instrument performance was confirmed by Monte Carlo
simulation with the McStas package. Under the target power of
100 kW, for high resolution mode, the resolution Δ d/d is
about 0.25% for 2θ=90∘ and the neutron flux is
4.5× 106 n/cm2/s at the sample position; for high
intensity mode, the neutron flux is 1.4× 107 n/cm2/s
and the resolution is about 0.50%. The high instrument flexibility
could allow and extend a broad of applications in materials science
and engineering fields in the future. This paper will discuss the
details of EMD instrument optical system design especially the
focusing guide and combinations of slits.
Synergistic optimization of renewable energy installations through evolution strategy
Authors: Dujardin Jérôme , Kahl Annelen , Lehning Michael
Published: April 2021

With large parts of the world moving toward renewable energies, there is an urgent need to organize this large-scale transition effectively. This paper presents a new methodology to guide the planning and siting of renewable electricity generation for countries or larger geographical regions. Its flexible approach accounts for the specific boundary conditions, constraints and available resources of the region of interest and enables solutions that optimize the interplay between the various types of generation. Evolution strategy permits a simultaneous optimization of the placement and the share of renewable electricity generation technologies that are to be added to a system, while most efficiently combining the new with the existing electricity generation and respecting the constraints of the electrical grid. Using Switzerland as case study, we demonstrate the method’s ability to devise national installation scenarios that are efficient, realistic with respect to land use and grid infrastructure and reduce significantly the need for seasonal storage. We show how the spatio-temporal variability of weather-driven electricity generation can be exploited to benefit the electrical system as a whole.
Identifying increasing risks of hazards for northern land-users caused by permafrost thaw: integrating scientific and community-based research approaches
Authors: Gibson Carolyn M , Brinkman Todd , Cold Helen , Brown Dana , Turetsky Merritt
Published: April 2021

Understanding the causes and consequences of environmental change is one of the key challenges facing researchers today as both types of information are required for decision making and adaptation planning. This need is particularly poignant in high latitude regions where permafrost thaw is causing widespread changes to local environments and the land-users who must adapt to changing conditions to sustain their livelihoods. The inextricable link between humans and their environments is recognized through socio-ecological systems research, yet many of these approaches employ top-down solutions that can lead to local irrelevance and create tensions amongst groups. We present and employ a framework for the use both of scientific and community-based knowledge sources that provides an enriched and thematic understanding of how permafrost thaw will affect northern land-users. Using geospatial modeling of permafrost vulnerability with community-based data from nine rural communities in Alaska, we show that permafrost thaw is a major driver of hazards for land-users and accounts for one-third to half of the hazards reported by community participants. This study develops an integrated permafrost-land-user system, providing a framework for thematic inquiry for future studies that will add value to large-scale institutional efforts and locally relevant observations of environmental change.
Daugavet- and delta-points in Banach spaces with unconditional bases
Authors: Abrahamsen Trond , Lima Vegard , Martiny André , Troyanski Stanimir
Published: April 2021

We study the existence of Daugavet- and delta-points in the unit sphere of Banach spaces with a

1
1

-unconditional basis. A norm one element

x
x

in a Banach space is a Daugavet-point (resp. delta-point) if every element in the unit ball (resp.

x
x

itself) is in the closed convex hull of unit ball elements that are almost at distance

2
2

from

x
x

. A Banach space has the Daugavet property (resp. diametral local diameter two property) if and only if every norm one element is a Daugavet-point (resp. delta-point). It is well-known that a Banach space with the Daugavet property does not have an unconditional basis. Similarly spaces with the diametral local diameter two property do not have an unconditional basis with suppression unconditional constant strictly less than

2
2

.

We show that no Banach space with a subsymmetric basis can have delta-points. In contrast we construct a Banach space with a

1
1

-unconditional basis with delta-points, but with no Daugavet-points, and a Banach space with a

1
1

-unconditional basis with a unit ball in which the Daugavet-points are weakly dense.
Homotopical rigidity of the pre-Lie operad
Authors: Dotsenko Vladimir , Khoroshkin Anton
Published: April 2021

We show that the celebrated operad of pre-Lie algebras is very rigid: it has no “non-obvious” degrees of freedom from either of the three points of view: deformations of maps to and from the “three graces of operad theory”, homotopy automorphisms, and operadic twisting. Examining the latter, it is possible to answer two questions of Markl from 2005 [Czechoslovak Math. J. 57 (2007), pp. 253–268; J. Lie Theory 17 (2007), pp. 241–261], including a Lie-theoretic version of the Deligne conjecture.
Almost reducibility for families of sequences of matrices
Authors: Barreira Luis , Valls Claudia
Published: April 2021

We consider the almost reducibility property of a nonautonomous dynamics with discrete time defined by a sequence of matrices. This corresponds to the reduction of the original nonautonomous dynamics to an autonomous dynamics via a coordinate change that preserves the Lyapunov exponents. In particular, we give a characterization of the almost reducibility of a sequence to a diagonal matrix and we use this result to characterize the class of matrices to which a given sequence is almost reducible. We also consider continuous

1
1

-parameter families of sequences of matrices and we show that the almost reducibility set of such a family is always an

F

σ
δ

F_{\sigma \delta }

-set. In addition, we show that for any

F

σ
δ

F_{\sigma \delta }

-set containing zero there exists a family with this set as its almost reducibility set.
Valproic acid-induced changes of 4D nuclear morphology in astrocyte cells
Authors: Kalinin Alexandr A. , Hou Xinhai , Ade Alex S. , Fon Gordon-Victor , Meixner Walter , Higgins Gerald A. , Sexton Jonathan Z. , Wan Xiang , Dinov Ivo D. , O’Meara Matthew J. , Athey Brian D.
Published: April 2021

Valproic acid-induced chromatin remodeling is reflected in time-dependent changes of 3D nuclear morphology of astrocyte cells potentially pertinent to astrocyte-to-neurons reprogramming. 4D morphometry allows accurate characterization of these changes, including increased nuclear size and higher shape irregularity under VPA treatment.
Agro-morphological and metabolomics analysis of low nitrogen stress response in Axonopus compressus
Authors: He Li , Teng Li , Tang Xiaomin , Long Wanwan , Wang Zhiyong , Wu Yang , Liao Li
Published: April 2021

Axonopus compressus also known as carpet grass is a robust, stoloniferous grass that can grow in minimal fertilization and resists well to abiotic and biotic stresses including low nitrogen (LN) stress. This study aimed at characterizing the agro-morphological and metabolome responses to LN in carpet grass leaves. Under LN stress, carpet grass increased yellowness of leaves and root dry matter while reduced turf quality and shoot dry weight. The metabolome comparison between samples from optimum and LN conditions indicated 304 differentially accumulated metabolites (DAMs), which could be classified into 12 major and 31 subclasses. The results revealed that the leaf tissues accumulated more anthocyanins and other flavonoid metabolites under LN stress. Conversely, amino acids, nucleic acids and their derivatives were reduced in response to LN stress. The overall evaluation of individual metabolites and pathways, and previous studies on metabolomes indicated that carpet grass reduced its energy consumption in leaves and increased the level of organic acid metabolism and secondary metabolism in order to resist LN stress conditions.
O78: SARCOPENIA IN LOCALLY ADVANCED BREAST CANCER: PREVALENCE, AND IMPACT ON CLINICAL AND ONCOLOGIC OUTCOMES
Authors: Collins PM , Elliott JA , Brennan MJ , McNamara M , O'Malley E , Barry K , Sweeney K , Malone C , Lowery A , McLaughlin R , Kerin MJ
Published: April 2021

Introduction

Sarcopenia in cancer may confer negative outcomes, but its prevalence and impact in the modern multimodal management of locally advanced breast cancer have not been systematically studied.

Method

Patients undergoing neoadjuvant therapy and surgery for locally advanced breast cancer between 2010 and 2015 were studied. Skeletal muscle index (SMI) and lean body mass (LBM) were determined. Sarcopenia was defined by computed tomography (CT) at L3 as SMI<38.5cm2/m2. Multivariable linear, logistic, and Cox regression analysis was undertaken to determine the independent impact of sarcopenia on clinical and oncologic outcome.

Result

258 patients were studied. Sarcopenia was present in 23.0%, 7.8% and 0.0% of patients with normal weight, overweight and obesity, respectively (P=0.001). Sarcopenia was not associated with baseline cT and cN stage, tumour grade, histologic type or receptor status. Patients with sarcopenia exhibited equivalent indices of neoadjuvant therapy response including ypT and ypN stage, pathologic complete response and Sataloff grade following surgical resection. Postoperatively, sarcopenia was not independently associated with comprehensive complications index (P=0.242), length of stay (P=0.716) or overall morbidity (P=0.365). However, on multivariable analysis, lower LBM independently predicted reduced invasive disease-free (P=0.049,HR0.93[95%CI0.87-1.00]) and overall (P=0.028,HR0.92[0.85-0.99]), but not disease-specific survival (P=0.070).

Conclusion

Consistent with a lack of association with baseline and post-treatment pathologic features, sarcopenia in locally advanced breast cancer is associated with reduced overall, but not disease-specific, survival. These data indicate that the prognostic impact of sarcopenia may be mediated by impaired performance status and increased non-cancer mortality.

Take-home message

Consistent with a lack of association with baseline and post-treatment pathologic features, sarcopenia in locally advanced breast cancer is associated with reduced overall, but not disease-specific, survival. These data indicate that the prognostic impact of sarcopenia may be mediated by impaired performance status and increased non-cancer mortality.
Reward, Salience, and Agency in Event-Related Potentials for Appetitive and Aversive Contexts
Authors: Stewardson Harry J , Sambrook Thomas D
Published: April 2021

Cognitive architectures tasked with swiftly and adaptively processing biologically important events are likely to classify these on two central axes: motivational salience, that is, those events’ importance and unexpectedness, and motivational value, the utility they hold, relative to that expected. Because of its temporal precision, electroencephalography provides an opportunity to resolve processes associated with these two axes. A focus of attention for the last two decades has been the feedback-related negativity (FRN), a frontocentral component occurring 240–340 ms after valenced events that are not fully predicted. Both motivational salience and value are present in such events and competing claims have been made for which of these is encoded by the FRN. The present study suggests that motivational value, in the form of a reward prediction error, is the primary determinant of the FRN in active contexts, while in both passive and active contexts, a weaker and earlier overlapping motivational salience component may be present.
Forecasting Trachoma Control and Identifying Transmission-Hotspots
Authors: Blumberg Seth , Prada Joaquin M , Tedijanto Christine , Deiner Michael S , Godwin William W , Emerson Paul M , Hooper Pamela J , Borlase Anna , Hollingsworth T Deirdre , Oldenburg Catherine E , Porco Travis C , Arnold Benjamin F , Lietman Thomas M
Published: April 2021

Background

Tremendous progress towards elimination of trachoma as a public health problem has been made. However, there are areas where the clinical indicator of disease, trachomatous inflammation—follicular (TF), remains prevalent. We quantify the progress that has been made, and forecast how TF prevalence will evolve with current interventions. We also determine the probability that a district is a transmission-hotspot based on its TF prevalence (ie, reproduction number greater than one).

Methods

Data on trachoma prevalence come from the GET2020 global repository organized by the World Health Organization and the International Trachoma Initiative. Forecasts of TF prevalence and the percent of districts with local control is achieved by regressing the coefficients of a fitted exponential distribution for the year-by-year distribution of TF prevalence. The probability of a district being a transmission-hotspot is extrapolated from the residuals of the regression.

Results

Forecasts suggest that with current interventions, 96.5% of surveyed districts will have TF prevalence among children aged 1–9 years <5% by 2030 (95% CI: 86.6%–100.0%). Districts with TF prevalence < 20% appear unlikely to be transmission-hotspots. However, a district having TF prevalence of over 28% in 2016–2019 corresponds to at least 50% probability of being a transmission-hotspot.

Conclusions

Sustainable control of trachoma appears achievable. However there are transmission-hotspots that are not responding to annual mass drug administration of azithromycin and require enhanced treatment in order to reach local control.
Gaze Estimation Using Neural Network And Logistic Regression
Authors: Xia Yifan , Liang Baosheng , Li Zhaotong , Gao Song
Published: April 2021

Currently, a large number of mature methods are available for gaze estimation. However, most regular gaze estimation approaches require additional hardware or platforms with professional equipment for data collection or computing that typically involve high costs and are relatively tedious. Besides, the implementation is particularly complex. Traditional gaze estimation approaches usually require systematic prior knowledge or expertise for practical operations. Moreover, they are primarily based on the characteristics of pupil and iris, which uses pupil shapes or infrared light and iris glint to estimate gaze, requiring high-quality images shot in special environments and other light source or professional equipment. We herein propose a two-stage gaze estimation method that relies on deep learning methods and logistic regression, which can be applied to various mobile platforms without additional hardware devices or systematic prior knowledge. A set of automatic and fast data collection mechanism is designed for collecting gaze images through a mobile platform camera. Additionally, we propose a new annotation method that improves the prediction accuracy and outperforms the traditional gridding annotation method. Our method achieves good results and can be adapted to different applications.
Neuronal nitric oxide synthase regulates regional brain perfusion in healthy humans
Authors: O’Gallagher Kevin , Puledda Francesca , O’Daly Owen , Ryan Matthew , Dancy Luke , Chowienczyk Philip J , Zelaya Fernando , Goadsby Peter J , Shah Ajay M
Published: April 2021

Aims

Neuronal nitric oxide synthase (nNOS) is highly expressed within the cardiovascular and nervous systems. Studies in genetically modified mice suggest roles in brain blood flow regulation while dysfunctional nNOS signalling is implicated in cerebrovascular ischaemia and migraine. Previous human studies have investigated the effects of non-selective NOS inhibition but there has been no direct investigation of the role of nNOS in human cerebrovascular regulation. We hypothesized that inhibition of the tonic effects of nNOS would result in global or localized changes in cerebral blood flow (CBF), as well as changes in functional brain connectivity.

Methods and results

We investigated the acute effects of a selective nNOS inhibitor, S-methyl-L-thiocitrulline (SMTC), on CBF and brain functional connectivity in healthy human volunteers (n = 19). We performed a randomized, placebo-controlled, crossover study with either intravenous SMTC or placebo, using magnetic resonance imaging protocols with arterial spin labelling and functional resting state neuroimaging. SMTC infusion induced an ∼4% decrease in resting global CBF [−2.3 (−0.3, −4.2) mL/100g/min, mean (95% confidence interval, CI), P = 0.02]. In a whole-brain voxel-wise factorial-design comparison of CBF maps, we identified a localized decrease in regional blood flow in the right hippocampus and parahippocampal gyrus following SMTC vs. placebo (2921 voxels; T = 7.0; x = 36; y = −32; z = −12; P < 0.001). This was accompanied by a decrease in functional connectivity to the left superior parietal lobule vs. placebo (484 voxels; T = 5.02; x = −14; y = −56; z = 74; P = 0.009). These analyses adjusted for the modest changes in mean arterial blood pressure induced by SMTC as compared to placebo [+8.7 mmHg (+1.8, +15.6), mean (95% CI), P = 0.009].

Conclusions

These data suggest a fundamental physiological role of nNOS in regulating regional CBF and functional connectivity in the human hippocampus. Our findings have relevance to the role of nNOS in the regulation of cerebral perfusion in health and disease.
Comprehensive cardiac rehabilitation for patients following infective endocarditis: results of the randomized CopenHeartIE trial
Authors: Rasmussen Trine Bernholdt , Zwisler Ann-Dorthe , Risom Signe Stelling , Sibilitz Kirstine Lærum , Christensen Jan , Bundgaard Henning , Moons Philip , Thygesen Lau Caspar , Lindschou Jane , Norekvål Tone Merete , Berg Selina Kikkenborg
Published: April 2021

Aims

Infective endocarditis is a complex and highly mortal disease requiring lengthy treatment. Physical and mental deconditioning is common. Nonetheless, rehabilitation is virtually unexplored in this population. The aim of this trial was therefore to investigate the effects of cardiac rehabilitation in patients following endocarditis.

Methods and results

In a randomized trial, adults with left-sided or cardiac device endocarditis were randomized 1:1 to 12 weeks of physical exercise training and five psycho-educational consultations (cardiac rehabilitation) vs. usual care without rehabilitation (control). Primary outcome was mental health measured by SF-36 Mental Component Summary (MCS) at 6 months. Secondary outcome was physical capacity measured by peak oxygen uptake (VO2) at 4 months. Exploratory outcomes were investigated. Low inclusion rate resulted in trial termination before reaching the target sample size. A total of 117 participants (mean age: 60 years, 81% male) were randomized to cardiac rehabilitation (n = 58) or to control (n = 59). Mental health and physical capacity at baseline were generally poor (MCS: 38.9–42.2 points, VO2 peak: 16.1–16.6 mL/kg/min). Cardiac rehabilitation compared with control showed no effect on mental health (MCS: 44.6 points vs. 48.8 points, P = 0.41) or physical capacity (VO2 peak: 19.9 mL/kg/min vs. 18.0 mL/kg/min, P = 0.09). Effects favouring the intervention were identified in exploratory outcomes including general fatigue (P = 0.005), and physical capacity as maximal power (W) (P = 0.005). Adherence to the intervention was 28%.

Conclusions

Results indicate no effect of cardiac rehabilitation in patients following endocarditis; however, lack of statistical power and poor adherence render findings inconclusive. Valuable insight into patients’ capabilities and safety was gained, and further investigations into rehabilitation needs and modes of delivery in this high-need population should be a future priority.

Registration

The trial is registered at ClinicalTrials.gov, NCT01512615
Sequence-Tagged-Site (STS) Markers of Arbitrary Genes: Development, Characterization and Analysis of Linkage in Black Spruce
Authors: Perry Daniel J , Bousquet Jean
Published: April 2021

Sequence-tagged-site (STS) markers of arbitrary genes were investigated in black spruce [Picea mariana (Mill.) B.S.P.]. Thirty-nine pairs of PCR primers were used to screen diverse panels of haploid and diploid DNAs for variation that could be detected by standard agarose gel electrophoresis without further manipulation of amplification products. Codominant length polymorphisms were revealed at 15 loci. Three of these loci also had null amplification alleles as did 3 other loci that had no apparent product-length variation. Dominant length polymorphisms were observed at 2 other loci. Alleles of codominant markers differed in size by as little as 1 bp to as much as an estimated 175 bp with nearly all insertions/deletions found in noncoding regions. Polymorphisms at 3 loci involved large (33 bp to at least 114 bp) direct repeats and similar repeats were found in 7 of 51 cDNAs sequenced. Allelic segregation was in accordance with Mendelian inheritance and linkage was detected for 5 of 63 pairwise combinations of loci tested. Codominant STS markers of 12 loci revealed an average heterozygosity of 0.26 and an average of 2.8 alleles in a range-wide sample of 22 trees.
The Number of Self-Incompatibility Alleles in a Finite, Subdivided Population
Authors: Schierup Mikkel Heide
Published: April 2021

The actual and effective number of gametophytic self-incompatibility alleles maintained at mutation-drift-selection equilibrium in a finite population subdivided as in the island model is investigated by stochastic simulations. The existing theory founded by Wright predicts that for a given population size the number of alleles maintained increases monotonically with decreasing migration as is the case for neutral alleles. The simulation results here show that this is not true. At migration rates above Nm = 0.01–0.1, the actual and effective number of alleles is lower than for an undivided population with the same number of individuals, and, contrary to Wright's theoretical expectation, the number of alleles is not much higher than for an undivided population unless Nm < 0.001. The same pattern is observed in a model where the alleles display symmetrical overdominant selection. This broadens the applicability of the results to include proposed models for the major histocompatibility (MHC) loci. For a subdivided population over a large range of migration rates, it appears that the number of self-incompatibility alleles (or MHC-alleles) observed can provide a rough estimate of the total number of individuals in the population but it underestimates the neutral effective size of the subdivided population.
Isolation of New Arabidopsis Mutants With Enhanced Disease Susceptibility to Pseudomonas syringae by Direct Screening
Authors: Volko Sigrid M , Boller Thomas , Ausubel Frederick M
Published: April 2021

To identify plant defense components that are important in restricting the growth of virulent pathogens, we screened for Arabidopsis mutants in the accession Columbia (carrying the transgene BGL2-GUS) that display enhanced disease susceptibility to the virulent bacterial pathogen Pseudomonas syringae pv. maculicola (Psm) ES4326. Among six (out of a total of 11 isolated) enhanced disease susceptibility (eds) mutants that were studied in detail, we identified one allele of the previously described npr1/nim1/sai1 mutation, which is affected in mounting a systemic acquired resistance response, one allele of the previously identified EDS5 gene, and four EDS genes that have not been previously described. The six eds mutants studied in detail (npr1-4, eds5-2, eds10-1, eds11-1, eds12-1, and eds13-1) displayed different patterns of enhanced susceptibility to a variety of phytopathogenic bacteria and to the obligate biotrophic fungal pathogen Erysiphe orontii, suggesting that particular EDS genes have pathogen-specific roles in conferring resistance. All six eds mutants retained the ability to mount a hypersensitive response and to restrict the growth of the avirulent strain Psm ES4326/avrRpt2. With the exception of npr1-4, the mutants were able to initiate a systemic acquired resistance (SAR) response, although enhanced growth of Psm ES4326 was still detectable in leaves of SAR-induced plants. The data presented here indicate that eds genes define a variety of components involved in limiting pathogen growth, that many additional EDS genes remain to be discovered, and that direct screens for mutants with altered susceptibility to pathogens are helpful in the dissection of complex pathogen response pathways in plants.
cot1: A Regulator of Arabidopsis Trichome Initiation
Authors: Szymanski Daniel B , Klis Daniel A , Larkin John C , Marks M David
Published: April 2021

In Arabidopsis, the timing and spatial arrangement of trichome initiation is tightly regulated and requires the activity of the GLABROUS1 (GL1) gene. The COTYLEDON TRICHOME 1 (COT1) gene affects trichome initiation during late stages of leaf development and is described in this article. In the wild-type background, cot1 has no observable effect on trichome initiation. GL1 overexpression in wild-type plants leads to a modest number of ectopic trichomes and to a decrease in trichome number on the adaxial leaf surface. The cot1 mutation enhances GL1-overexpression-dependent ectopic trichome formation and also induces increased leaf trichome initiation. The expressivity of the cot1 phenotype is sensitive to cot1 and 35S::GL1 gene dosage, and the most severe phenotypes are observed when cot1 and 35S::GL1 are homozygous. The COT1 locus is located on chromosome 2 15.3 cM north of er. Analysis of the interaction between cot1, try, and 35S::GL1 suggests that COT1 is part of a complex signal transduction pathway that regulates GL1-dependent adoption of the trichome cell fate.
A Genetic Screen for Modifiers of UFO Meristem Activity Identifies Three Novel FUSED FLORAL ORGANS Genes Required for Early Flower Development in Arabidopsis
Authors: Levin Joshua Z , Fletcher Jennifer C , Chen Xuemei , Meyerowitz Elliot M
Published: April 2021

In a screen to identify novel genes required for early Arabidopsis flower development, we isolated four independent mutations that enhance the Ufo phenotype toward the production of filamentous structures in place of flowers. The mutants fall into three complementation groups, which we have termed FUSED FLORAL ORGANS (FFO) loci. ffo mutants have specific defects in floral organ separation and/or positioning; thus, the FFO genes identify components of a boundary formation mechanism(s)acting between developing floral organ primordia. FFO1 and FFO3 have specific functions in cauline leaf/stem separation and in first- and third-whorl floral organ separation, with FFO3 likely acting to establish and FFO1 to maintain floral organ boundaries. FFO2 acts at early floral stages to regulate floral organ number and positioning and to control organ separation within and between whorls. Plants doubly mutant for two ffo alleles display additive phenotypes, indicating that the FFO genes may act in separate pathways. Plants doubly mutant for an ffo gene and for ufo, lfy, or clv3 reveal that the FFO genes play roles related to those of UFO and LFY in floral meristem initiation and that FFO2 and FFO3 may act to control cell proliferation late in inflorescence development.
Major Chromosomal Rearrangements Induced by T-DNA Transformation in Arabidopsis
Authors: Nacry Philippe , Camilleri Christine , Courtial Béatrice , Caboche Michel , Bouchez David
Published: April 2021

We show that major chromosomal rearrangements can occur upon T-DNA transformation of Arabidopsis thaliana. In the ACL4 line, two T-DNA insertion loci were found; one is a tandem T-DNA insert in a head-to-head orientation, and the other is a truncated insert with only the left part of the T-region. The four flanking DNA regions were isolated and located on the Arabidopsis chromosomes; for both inserts, one side of the T-DNA maps to chromosome 2, whereas the other side maps to chromosome 3. Both chromosome 3 flanking regions map to the same location, despite a 1.4-kb deletion at this point, whereas chromosome 2 flanking regions are located 40 cM apart on the bottom arm of chromosome 2. These results strongly suggest a reciprocal translocation between chromosomes 2 and 3, with the breakpoints located at the T-DNA insertion sites. The interchanged fragments roughly correspond to the 20-cM distal ends of both chromosomes. Moreover, a large inversion, spanning 40 cM on the genetic map, occurs on the bottom arm of chromosome 2. This was confirmed by genetic analyses that demonstrated a strong reduction of recombination in the inverted region. Models for T-DNA integration and the consequences for T-DNA tagging are discussed in light of these results.
Potential Retroviruses in Plants: Tat1 Is Related to a Group of Arabidopsis thaliana Ty3/gypsy Retrotransposons That Encode Envelope-Like Proteins
Authors: Wright David A , Voytas Daniel F
Published: April 2021

Tat1 was originally identified as an insertion near the Arabidopsis thaliana SAM1 gene. We provide evidence that Tat1 is a retrotransposon and that previously described insertions are solo long terminal repeats (LTRs) left behind after the deletion of coding regions of full-length elements. Three Tat1 insertions were characterized that have retrotransposon features, including a primer binding site complementary to an A. thaliana asparagine tRNA and an open reading frame (ORF) with ~44% amino acid sequence similarity to the gag protein of the Zea mays retrotransposon Zeon-1. Tat1 elements have large, polymorphic 3′ noncoding regions that may contain transduced DNA sequences; a 477-base insertion in the 3′ noncoding region of the Tat1-3 element contains part of a related retrotransposon and sequences similar to the nontranslated leader sequence of AT-P5C1, a gene for pyrroline-5-carboxylate reductase. Analysis of DNA sequences generated by the A. thaliana genome project identified 10 families of Ty3/gypsy retrotransposons, which share up to 51 and 62% amino-acid similarity to the ORFs of Tat1 and the A. thaliana Athila element, respectively. Phylogenetic analyses resolved the plant Ty3/gypsy elements into two lineages, one of which includes homologs of Tat1 and Athila. Four families of A. thaliana elements within the Tat/Athila lineage encode a conserved ORF after integrase at a position occupied by the envelope gene in retroviruses and in some insect Ty3/gypsy retrotransposons. Like retroviral envelope genes, this ORF encodes a transmembrane domain and, in some insertions, a putative secretory signal sequence. This suggests that Tat/Athila retrotransposons may produce enveloped virions and may be infectious.
Analysis of Natural Allelic Variation at Flowering Time Loci in the Landsberg erecta and Cape Verde Islands Ecotypes of Arabidopsis thaliana
Authors: Alonso-Blanco Carlos , El-Assal Salah El-Din , Coupland George , Koornneef Maarten
Published: April 2021

We have analyzed the flowering behavior of two Arabidopsis ecotypes: the laboratory strain Landsberg erecta (Ler) and an ecotype from the tropical Cape Verde Islands (Cvi). They differ little in their flowering phenotypes and in their responses to photoperiod length changes and to vernalization treatment. However, segregating populations derived from crosses between them showed a much larger variation. An approach of quantitative trait locus (QTL) mapping in recombinant inbred lines (RILs) grown under three environments differing in day-length and/or vernalization treatment has been used to detect and locate flowering loci. Four main QTLs were identified, designated early day-length insensitive (EDI), flowering F, G, and H (FLF, FLG, and FLH, respectively), to which most of the flowering behavior differences could be attributed. To further characterize the individual loci, near isogenic lines were constructed by introgressing Cvi early alleles of EDI and FLH into the Ler genetic background. EDI-Cvi alleles produce earliness under both long- and short-day photoperiods, rendering Ler plants almost day-length neutral. In addition, RILs were selected to analyze FLF and FLG. These loci interact epistatically and RILs carrying late alleles at FLF and FLG were very responsive to vernalization and showed an increased response to photoperiod length changes. The possible role of these loci for the control of flowering is discussed in the context of the current Arabidopsis model.
Multiple Recombination Events Maintain Sequence Identity Among Members of the Nitrogenase Multigene Family in Rhizobium etli
Authors: Rodríguez César , Romero David
Published: April 2021

A distinctive characteristic of the Rhizobium genome is the frequent finding of reiterated sequences, which often constitute multigene families. Interestingly, these families usually maintain a high degree of nucleotide sequence identity. It is commonly assumed that apparent gene conversion between reiterated elements might lead to concerted variation among members of a multigene family. However, the operation of this mechanism has not yet been demonstrated in the Rhizobiaceae. In this work, we employed different genetic constructions to address the role of apparent gene conversion as a homogenizing mechanism between members of the plasmid-located nitrogenase multigene family in Rhizobium etli. Our results show that a 28-bp insertion into one of the nitrogenase reiterations can be corrected by multiple recombination events, including apparent gene conversion. The correction process was dependent on the presence of both a wild-type recA gene and wild-type copies of the nitrogenase reiterations. Frequencies of apparent gene conversion to the wild-type nitrogenase reiterations were the same when the insertion to be corrected was located either in cis or in trans, indicating that this event frequently occurs through intermolecular interactions. Interestingly, a high frequency of multiple crossovers was observed, suggesting that these large plasmid molecules are engaging repeatedly in recombination events, in a situation akin to phage recombination or recombination among small, high-copy number plasmids.
The Transcriptional Activator Imp2p Maintains Ion Homeostasis in Saccharomyces cerevisiae
Authors: Masson Jean-Yves , Ramotar Dindial
Published: April 2021

Yeast cells deficient in the transcriptional activator Imp2p are viable, but display marked hypersensitivity to a variety of oxidative agents. We now report that imp2 null mutants are also extremely sensitive to elevated levels of the monovalent ions, Na+ and Li+, as well as to the divalent ions Ca2+, Mn2+, Zn2+, and Cu2+, but not to Cd2+, Mg2+, Co2+, Ni2+, and Fe2+, as compared to the parent strain. We next searched for multicopy suppressor genes that would allow the imp2Δ mutant to grow under high salt conditions. Two genes that independently restored normal salt-resistance to the imp2Δ mutant, ENA1 and HAL3, were isolated. ENA1 encodes a P-type ion pump involved in monovalent ion efflux from the cell, while HAL3 encodes a protein required for activating the expression of Ena1p. Neither ENA1 nor HAL3 gene expression was positively regulated by Imp2p. Moreover, the imp2 ena1 double mutant was exquisitely sensitive to Na+/Li+ cations, as compared to either single mutant, implying that Imp2p mediates Na+/Li+ cation homeostasis independently of Ena1p.
Two Sites in the Delta Gene Region Contribute to Naturally Occurring Variation in Bristle Number in Drosophila melanogaster
Authors: Long Anthony D , Lyman Richard F , Langley Charles H , Mackay Trudy F C
Published: April 2021

A restriction enzyme survey of a 57-kb region including the gene Delta uncovered 53 polymorphic molecular markers in a sample of 55 naturally occurring chromosomes. A permutation test, which assesses the significance of the molecular marker with the largest effect on bristle variation in four genetic backgrounds relative to permuted data-sets, found two sites that were independently associated with variation in bristle number. A common site in the second intron of Delta affected only sternopleural bristle number, and another common site in the fifth intron affected only abdominal bristle number in females. Under an additive genetic model, the polymorphism in the second intron may account for 12% of the total genetic variation in sternopleural bristle number due to third chromosomes, and the site in the fifth intron may account for 6% of the total variation in female abdominal bristle number due to the third chromosomes. These results suggest the following: (1) models that incorporate balancing selection are more consistent with observations than deleterious mutation-selection equilibrium models, (2) mapped quantitative trait loci of large effect may not represent a single variable site at a genetic locus, and (3) linkage disequilibrium can be used as a tool for understanding the molecular basis of quantitative variation.