Summary
The tempo and mode of adaptive evolution determine how natural selection shapes patterns of genetic diversity in DNA polymorphism data. While slow mutation‐limited adaptation leads to ...classical footprints of ‘hard’ selective sweeps, these patterns are different when adaptation responds quickly to a novel selection pressure, acting either on standing genetic variation or on recurrent new mutation. In the past decade, corresponding footprints of ‘soft’ selective sweeps have been described both in theoretical models and in empirical data.
Here, we summarize the key theoretical concepts and contrast model predictions with observed patterns in Drosophila, humans, and microbes.
Evidence in all cases shows that ‘soft’ patterns of rapid adaptation are frequent. However, theory and data also point to a role of complex adaptive histories in rapid evolution.
While existing theory allows for important implications on the tempo and mode of the adaptive process, complex footprints observed in data are, as yet, insufficiently covered by models. They call for in‐depth empirical study and further model development.
ABSTRACT
Phoresy is a type of interaction in which one species, the phoront, uses another species, the dispersal host, for transportation to new habitats or resources. Despite being a widespread ...behaviour, little is known about the ecology and evolution of phoresy. Our goal is to provide a comprehensive review of phoretic dispersal in animals and to bring renewed attention to this subject. We surveyed literature published between 1900 and 2020 to understand the extent of known higher‐level taxonomic diversity (phyla, classes, and orders) and functional aspects of animals that use phoretic dispersal. Species dispersing phoretically have been observed in at least 13 animal phyla, 25 classes, and 60 orders. The majority of known phoronts are arthropods (Phylum Euarthropoda) in terrestrial habitats, but phoronts also occur in freshwater and marine environments. Marine phoronts may be severely under‐represented in the literature due to the relative difficulty of studying these systems. Phoronts are generally small with low mobility and use habitats or resources that are ephemeral and/or widely dispersed. Many phoronts are also parasites. In general, animals that engage in phoresy use a wide variety of morphological and behavioural traits for locating, attaching to, and detaching from dispersal hosts, but the exact mechanisms behind these activities are largely unknown. In addition to diversity, we discuss the evolution of phoresy including the long‐standing idea that it can be a precursor to parasitism and other forms of symbioses. Finally, we suggest several areas of future research to improve our understanding of phoresy and its ecological and evolutionary significance.
A linear reversing control strategy based on the stable and feasible domains of a hitch angle is proposed to address the linear reversing problem with expectation caused by unstable open-loop ...conditions of semi-trailer trains during reverse driving. In the reversing process, the coupling relationship amongst the location parameters, such as hitch angle, semi-trailer posture angle and axis offset, including the influence of these parameters on the reversing stability and feasibility of semi-trailer trains, is analysed. The stable and feasible domains of the hitch angle when the semi-trailer is reversed in an expected straight line are determined. Based on this, the semi-trailer linear reversing control strategy is established. The tracking control of the linear reversing path is adopted by the variable universe fuzzy control, and the co-simulation based on ADAMS and MATLAB/Simulink and the subsequent actual vehicle experiment are conducted. Simulation and experimental results show that the proposed linear reversing control strategy of the semi-trailer based on the hitch angle stable and feasible domains can accurately realise the linear reverse-path tracking of the semi-trailer train, effectively avoiding the problems of jack-knife and trailer swing during the reversing process. Thus, the difficulty of the straight reverse operation is substantially reduced.
•The coupling relationship amongst the reversing positioning parameters is analysed.•The stable and feasible domains of the hitch angle are determined.•The control strategy is established by using the variable universe fuzzy control.•Verification of simulation and experiment in multiple working conditions.
Surgical knots are particularly challenged by high-strength suture material. It was hypothesized that sutures in a double-stranded looped configuration present mechanical advantages.
This in vitro ...biomechanical study repeatedly tested 12 different knots with a static distraction material testing machine with a constant tensile speed. The cow hitch, its altered version, and conventional half hitches were also tested on bovine tendon. Suture material was braided polyblend non-bioresorbable polyester. Primary outcome was knot security (stiffness) at clinical failure (≥3mm displacement). Secondary outcomes were knot size and loop security.
Double-stranded looped knots were up to three times stronger than one and a half- and single-stranded knots. The cow hitch was stiffest (mean 185 95% CI 172–197Newton per millimeter N/mm) (p<0.001), followed by the Nice knot (169 154–183N/mm). It was stiffer than half hitches (65 53–78N/mm). These findings remained in tendons (82 77–86 and 40 32–49N/mm, p<0.001). The cow hitch (7.6mm3) and Nice knot (6.1mm3) were smaller than half hitches (9.5mm3). Loop security did not differ between the cow hitch and Nice knot, but was higher in the cow hitch than half hitch (158 120–196N and 85 57–113N, p<0.001).
Double-stranded knot configurations with a loop on one side are mechanically stronger and stiffer, less bulky, and preserve applied tension during tying better than conventional knots. The best performing and technically most simple knots best suited to exploit enormous mechanical capabilities of modern high-strength suture material are the cow hitch and Nice knot.
Not applicable due to the biomechanical nature of the study.
The real-time monitoring of the load in fanning by the sensor installed on the tractor's three-point hitch can effectively improve the fanning efficiency and force-position combined control, reduce ...the compaction risk of the wheel on the soil and reduce the fuel consumption in fanning process. However, the measurement and quantification of the loads on the three-point hitch have some problems remaining unresolved: testing the accuracy and reliability of a load measuring system is hard when the tractor works in a field, the mathematical model of spatial forces usually lacks a practical and effective validation, and the calibration process of the measurement system is inconvenient and incomplete while easily causing a low accuracy. Specifically, this paper builds a new spatial-force mathematical model based on the geometry of a three-point hitch. To eliminate the discrepancy of the geometric model with the actual structure and to refine the mathematical model, a calibration process is conducted by developing a calibration bench, which is equipped with a data acquisition system and a multi-parameter monitoring interface. The three-point hitch installed on this calibration bench is subject to steady-state loading. The loading force, angle of the lower drawbar, and three-component forces (three shaft pin sensors' forces) of the three-point hitch are well measured. With applying for the measured data to calibrate the theoretical mathematic model eventually derives the resultant force from all the three-component forces, a dynamical loading bench was developed to test the calculated resultant force for the three-point hitch during the sinusoidal and randomly variant dynamical loadings tests. A hitch force measurement system is also developed to collect real-time data and calculate the resultant force of measured three-component forces through the calibrated mathematical model. The results of the dynamical loading tests show that the average relative error MRE = 1.09% with an average force measurement time delay being Ar = 0.5 s, the root mean square error RMSE = 59.3 N, and the coefficient of determination R1 = 0.9903. As observed, the shape and the trend of the generated resultant force curve are basically the dynamical loading force. The dynamical loading test proves the high efficacy and reliability of the proposed indoor calibration method for calculating the load based on the three-component forces as measured on the three-point hitch. Besides, the preliminary study of the proposed method on the hitch load provides great potential to improve the indoor sixcomponent measurement and quantification of both the force and momentum acting on the three-point hitch.
Biallelic IMPAD1 pathogenic variants leads to deficiency of GPAPP (Golgi 3‐prime phosphoadenosine 5‐prime phosphate 3‐prime phosphatase) protein and clinically causes chondrodysplasia, which is ...characterized by short stature with short limbs, craniofacial malformations, cleft palate, hand and foot anomalies, and various radiographic skeletal manifestations. Here we describe prenatal presentation of GPAPP deficiency caused by novel biallelic pathogenic variants, 2 base pair duplication in exon 2 of IMAPD1 gene in a patient of Asian‐Indian origin. Further we report on diagnostic clues of prenatal presentation of GPAPP deficiency through ultrasonography, fetal MRI, and postmortem findings. We also provide evidence of pathophysiology of underlying GPAPP deficiency in the form of disorganization and dysplastic chondrocytes and reduced sulfation of glycoproteins through histopathology of cartilage similar to that described in mice IMPAD1 homozygous mutant model.
Over the past five or six decades, contamination and pollution of the world's enclosed seas, coastal waters and the wider open oceans by plastics and other synthetic, non-biodegradable materials ...(generally known as 'marine debris') has been an ever-increasing phenomenon. The sources of these polluting materials are both land- and marine-based, their origins may be local or distant, and the environmental consequences are many and varied. The more widely recognized problems are typically associated with entanglement, ingestion, suffocation and general debilitation, and are often related to stranding events and public perception. Among the less frequently recognized and recorded problems are global hazards to shipping, fisheries and other maritime activities. Today, there are rapidly developing research interests in the biota attracted to freely floating (i.e. pelagic) marine debris, commonly known as 'hangers-on and hitch-hikers' as well as material sinking to the sea floor despite being buoyant. Dispersal of aggressive alien and invasive species by these mechanisms leads one to reflect on the possibilities that ensuing invasions could endanger sensitive, or at-risk coastal environments (both marine and terrestrial) far from their native habitats.
When carrying out tillage with tractor, engine load includes ploughing load, rolling resistance, hydraulic system load and cooling system load. Traditional draft-position mixed control systems for ...controlling tractor tillage depth use tillage resistance sensors to monitor engine load, but this cannot accurately express load on the engine. A control method of tillage depth is proposed, which estimates the load on the engine through the engine throttle opening, engine speed and an engine load characteristic model. The engine can be adjusted to provide high power and low fuel consumption working conditions by controlling plough depth. Firstly, a tillage depth control system based on engine load characteristics is established. Taking JM804 tractor as an example, the load characteristics of the engine were analysed, the ideal working state for engine operation was set, and a control strategy was designed. Secondly, to verify the feasibility of the method, a tractor-plough tillage mechanics model was established, and a simulation model of the coordinated control of engine load characteristics and tillage depth was built. The simulation results show that the purpose of stabilising the engine load can be achieved by adjusting the tillage depth. Finally, a test bench system was built. Bench test results showed that when the soil resistance increases greatly, engine speed drops rapidly and leaves the set ideal operating range. The control system could reduce the tillage depth and tillage resistance by lifting the plough stabilising the engine speed to work within the high power and low fuel consumption range.
•Load estimated by engine load characteristics model.•Model based on accelerator pedal position and engine speed.•Control method combines engine load and tillage depth target.•The ideal state of engine working condition was created.
Purpose
To describe a novel modification of tuck-in Tenon's patch graft (TPG) using temporary horizontal mattress sutures and fibrin glue to hitch the graft in the management of corneal perforations.
...Design
Ambispective interventional case series.
Methods
Modified technique of autologous TPG was used to seal corneal perforations measuring 3–5 mm, using horizontal mattress sutures to hitch the graft in a lamellar pocket, followed by application of fibrin glue. The horizontal mattress sutures were removed after the reformation of the anterior chamber. The primary outcome measure was a well formed anterior chamber in the post-operative period and the secondary outcome was epithelization time.
Results
The surgery was performed in 22 eyes. The mean age was 43.86 ± 16.02 (26–66) years, with 14 males and eight females. The etiologies of corneal perforation included dry eye (n = 10), neurotrophic keratitis (n = 6), trauma (n = 2), chemical injury (n = 2) and exposure (n = 2). The mean size of the perforation with the thinned-out area was 4.3 mm (range 3–5 mm). The mean duration of epithelialization was 14.31 ± 2.63 days (7–21 days). No intraoperative complications were observed. All eyes had a well-formed anterior chamber in the immediate postoperative period. Postoperatively, two eyes had graft pseudoectasia due to a thick graft and supra tenon haemorrhage each; one eye each had graft thinning with the formation of pseudopterygium and graft melting.
Conclusion
Tenon's patch graft, along with the use of temporary horizontal mattress sutures and fibrin glue, is an effective modification of the technique for managing corneal perforations measuring 3–5 mm.
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