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• Multiple studies reported inter-strain recombination events in Treponema pallidum. • Treponema pallidum lacks vectors for horizontal DNA transfer. • Here, we elucidate the first step in recombination as a coinfection with two strains. • No compelling evidence of coinfection by two Treponema strains was reported so far. • PCR chimeric clones amplified from the sample resembled recombinant treponemal loci. The etiological agent of yaws is the spirochete Treponema pallidum (TP) subsp. pertenue (TPE) and infects the children of Papua New Guinea, causing ulcerative skin lesions that impairs normal growth and development. Closely related strains of Treponema pallidum subsp. pertenue, J E 11, and T E 13 were detected in an ulcer biospecimen derived from a 5-year-old yaws patient. Cloning experiments validated the presence of two distinct but similar genotypes, namely T E 13 and J E 11, co-occurring within a single host. While coinfection with highly related TPE strains has only limited epidemiological and clinical relevance, this is the first documented coinfection with genetically distinct TP strains in a single patient. Similar coinfections in the past were explained by the existence of over a dozen recombinant loci present in the TP genomes as a result of inter-strain or inter-subspecies recombination events following an anticipated scenario of TP coinfection, i.e., uptake of foreign DNA and DNA recombination. [Display omitted] [ABSTRACT FROM AUTHOR]

Yaw error measurements using a new designed yaw sensor were carried out to determine the characteristics of yaw errors and analyze the behavior of the structural guide. Laser interferometers have generally been used in calibration laboratories for the angular measurement of measuring tape calibration systems, and their performance must be verified to determine whether it meets the laboratory specifications. The yaw sensor technique is identical to the error compensation used in a measuring tape calibration, and also has some special parameters. Although the yaw error observation period is very short, it is sufficiently accurate for a carriage yaw sensor. The results of a yaw error measurement comparison between a yaw sensor and the angular measurement system of a laser interferometer were satisfactory. The measurement uncertainty of a yaw sensor calibration was approximately U  = 40 arcsec at a confidence level of 95%. [ABSTRACT FROM AUTHOR]

This paper presents an experimental investigation on 6-DOF vortex-induced motion response of a tethered buoyancy can under conditions of different tether lengths. The buoyancy can was mounted vertically, with the diameter of 150 mm and the length of 700 mm. The responses of trajectory, amplitude, frequency and other parameters were analyzed in detail under conditions of different tether lengths and height above the water. In addition, during the experiment, obvious yaw motion is observed and the yaw characteristics were investigated. The results show that when the reduced velocity is small (less than about 3.5), the motion amplitude is small and irregular and when the reduced velocity is large (3.5< U r < 15), the in-line vibration frequency is two times the transverse vibration frequency and the trajectory of the cylinder is in “figure 8” shape. A strong connection between the yaw motion frequency and the vibration frequency was also found. Moreover, the mean drag coefficient of the buoyancy can was measured and the amplification effect of VIV on drag coefficient was observed. [ABSTRACT FROM AUTHOR]

Many neglected tropical diseases (NTDs) affect the skin, causing considerable disability, stigma, and exacerbation of poverty. However, there has been relatively little investment into laboratory research, epidemiology, diagnostic tools or management strategies to control tropical skin disease. Integration may advance the control of skin disease across a range of domains, including mapping, diagnosis, clinical management, and community control measures such as mass drug administration. Examples of successful integration strategies include programs targeting scabies, impetigo, yaws, and diseases causing lymphoedema. Future strategies should build on these experiences and the experience of integration of other NTDs, strengthen existing health systems, and contribute toward the attainment of Universal Health Coverage. Strong partnerships and political support and will be necessary to achieve these goals. [ABSTRACT FROM AUTHOR]

Treponema pallidum infections causing yaws disease and venereal syphilis are globally widespread in human populations, infecting hundreds of thousands and millions annually respectively; endemic syphilis is much less common, and pinta has not been observed in decades. We discuss controversy surrounding the origin, evolution and history of these pathogens in light of available molecular and anthropological evidence. These bacteria (or close relatives) seem to affect many wild African nonhuman primate (NHP) species, though to date only a single NHP Treponema pallidum genome has been published, hindering detection of spillover events and our understanding of potential wildlife reservoirs. Similarly, only ten genomes of Treponema pallidum infecting humans have been published, impeding a full understanding of their diversity and evolutionary history. Research efforts have been hampered by the difficulty of culturing and propagating Treponema pallidum. Here we highlight avenues of research recently opened by the coupling of hybridization capture and next-generation sequencing. We present data generated with such an approach suggesting that asymptomatic bones from NHP occasionally contain enough treponemal DNA to recover large fractions of their genomes. We expect that these methods, which naturally can be applied to modern biopsy samples and ancient human bones, will soon considerably improve our understanding of these enigmatic pathogens and lay rest to old yet unresolved controversies. [ABSTRACT FROM AUTHOR]

Yaws is a chronic infection caused by the bacterium Treponema pallidum susp. pertenue (TPE) that was thought to be an exclusive human pathogen but was recently found and confirmed in nonhuman primates. In this paper, we develop the first compartmental ODE model for TPE infection with treatment of wild olive baboons. We solve for disease-free and endemic equilibria and give conditions on local and global stability of the disease-free equilibrium. We calibrate the model based on the data from Lake Manyara National Park in Tanzania. We use the model to help the park managers devise an effective strategy for treatment. We show that an increasing treatment rate yields a decrease in disease prevalence. This indicates that TPE can be eliminated through intense management in closed population. Specifically, we show that if the whole population is treated at least once every 5-6 years, a disease-free equilibrium can be reached. Furthermore, we demonstrate that to see a substantial decrease of TPE infection to near-elimination levels within 15 years, the whole population needs to be treated every 2-3 years. • A first ODE model for Treponema (TPE) infection with treatment of wild baboons. • TPE can be eliminated through management in a closed population. • The population needs to be treated once every 2-3 years over 15 years. • Long term field studies on behavioural and infectious disease research are needed. [ABSTRACT FROM AUTHOR]

Three-dimensional transient CFD (Computational Fluid Dynamics) simulations are performed to study the hydrodynamic performance of an ocean current turbine with a 3.0 m diameter 3-bladed rotor. Simulations are based on the RANS (Reynolds Averaged Navier–Stokes) equations and the shear stress transport k-ω turbulent model is utilized. The influence of yaw angle and upstream TI (turbulence intensity) on the turbine performance is studied. The CFD method is first validated using existing experimental data and good agreement is obtained. The performance of the turbine, including power, thrust and wake characteristics are then studied at different TSR (tip speed ratios). The turbine obtains a maximum coefficient of power ( C p ) of 0.4642 at TSR = 6 and the coefficient of thrust ( C t ) increases over the entire evaluated TSR range to a value of 0.8788 at a TSR = 10. Simulations are also performed at four different yaw angles, 0°, 5°, 10° and 15° which show that both C p and C t decrease as yaw angle increases. Finally simulations of three different TIs, 3%, 6% and 9%, are performed and analyzed. Results show that TI minimally affects C p and C t for the considered TI range, but greatly influences the downstream wake structure. [ABSTRACT FROM AUTHOR]

Deep-draft design of semi-submersibles improves vertical motions but leads to critical vortex-induced motions (VIM) attributable to fluctuating loads on columns. As characteristic components, both columns and pontoons produce complex wake interference and thus have significant influences on the VIM of semi-submersibles. This paper presents an experimental study on VIM of deep-draft semi-submersibles (DDS) to examine the effects of pontoons and column configuration. There were four test models including four-pontoon DDS, two-pontoon DDS, four-square-column structure and four-rhombic-column structure with no pontoons. A number of current headings and reduced velocities were considered. The main results reveal that the two-pontoon DDS can generate larger lift forces in comparison with the four-pontoon DDS; consequently, the transverse motion amplitudes at high reduced velocities are larger. However, the four-square-column structure with no pontoons shows the most significant transverse and yaw responses owing to the largest excitation forces induced by the well-established wake. On the other hand, similar trend and values in the transverse response are observed for the four-square-column structure at the 45° current heading and for the four-rhombic-column structure at the 0° current heading. The incidence angle related to columns has more significant effect on the VIM of DDS than that related to the platform. [ABSTRACT FROM AUTHOR]

Aerodynamic drag is the main source of losses in cycling so improving the bicycle aerodynamic is a fundamental key factor to increase the performance. The aim of this research is to evaluate and compare the aerodynamic performance of racing bicycle wheels by means of CFD RANS numerical models: it is based on a previous work that reported the development of the numerical model. The aim of this work is to assess the capability of CFD RANS simulations to predict the aerodynamic performance of modern racing bicycle wheels. Drag and side forces are resolved over the range of different yaw angles. [ABSTRACT FROM AUTHOR]

This paper deals with the problem of a vehicle speed prediction from tire yaw marks. In forensic science, the evidences from accident scene in most cases are the main information preparing the accident report. Analysis of tire yaw marks when vehicle speed is too great to maintain the proposed circular path is the main object of this paper. Errors caused by yaw mark trajectory measurement could have influences on choice of calculation methodology and on obtained results. Photographs of traffic accident scene eliminate the uncertainties of evidences measurement and enable expert to use photogrammetric methods for determination of necessary geometrical parameters. [ABSTRACT FROM AUTHOR]

Yaws is endemic in west Africa, southeast Asia, and the Pacific region. To eradicate yaws by 2020, WHO has launched a campaign of mass treatment with azithromycin. Progress has been made towards achievement of this ambitious goal, including the validation of point-of-care and molecular diagnostic tests and piloting of the strategy in several countries, including Ghana, Vanuatu, and Papua New Guinea. Gaps in knowledge need to be addressed to allow refinement of the eradication strategy. Studies exploring determinants of the spatial distribution of yaws are needed to help with the completion of baseline mapping. The finding that Haemophilus ducreyi causes lesions similar to yaws is particularly important and further work is needed to assess the effect of azithromycin on these lesions. The integration of diagnostic tests into different stages of the eradication campaign needs investigation. Finally, studies must be done to inform the optimum mass-treatment strategy for sustainable interruption of transmission. [ABSTRACT FROM AUTHOR]

We present a description and differential diagnosis of pathological lesions observed on skeletal elements found during surface surveys of the Nagabaka site on Miyako-jima Island, Japan. The Nagabaka site served as a bone depository during the Early Modern period (c. AD 1600–1870). We evaluated remains via macroscopic inspection to classify infectious lesions according to criteria in Weston (2008) . We also obtained CT scans of three bone elements for more extensive lesion analysis and carried out a differential diagnosis utilizing paleopathological literature. Subsequent investigation yielded convincing evidence of treponemal infection on 23 skeletal elements. Based on known geographical spread and morphological comparisons of lesion patterning, we identified yaws as the pathogen most likely responsible, but refrained from calculating site-wide prevalence due to the taphonomical nature of the sample. Lastly, we review treponemal infection rates in other archaeological sites throughout Southeast Asia and Oceania, and assess similar ecological and cultural factors contributing to the observed pathologies. Nagabaka is the northernmost site in the world where yaws has so far been identified. Located between sites between Mainland China and Western Micronesia where this infection has been previously identified, Miyako-jima holds an important geographical position for research into the historical spread of pathogens. [ABSTRACT FROM AUTHOR]

More efficient agricultural machinery is needed as agricultural areas become more limited and energy and labor costs increase. To increase their efficiency, trajectory tracking problem of an autonomous tractor, as an agricultural production machine, has been investigated in this study. As a widely used model-based approach, model predictive control is preferred in this paper to control the yaw dynamics of the tractor which can deal with the constraints on the states and the actuators in a system. The yaw dynamics is identified by using nonlinear least squares frequency domain system identification. The speed is controlled by a proportional–integral–derivative controller and a kinematic trajectory controller is used to calculate the desired speed and the desired yaw rate signals for the subsystems in order to minimize the tracking errors in both the longitudinal and transversal directions. The experimental results show the accuracy and the efficiency of the proposed control scheme in which the euclidean error is below 40 cm for time-based straight line trajectories and 60 cm for time-based curved line trajectories, respectively. [ABSTRACT FROM AUTHOR]

Treponema pallidum strains are closely related at the genome level but cause distinct diseases. Subspecies pallidum (TPA) is the causative agent of syphilis, subspecies pertenue (TPE) causes yaws while subspecies endemicum (TEN) causes bejel (endemic syphilis). Compared to the majority of treponemal genomic regions, several chromosomal loci were found to be more diverse. To assess genetic variability in diverse genomic positions, we have selected (based on published genomic data) and sequenced five variable loci, TP0304, TP0346, TP0488, TP0515 and TP0558, in 19 reference Treponema pallidum strains including all T. pallidum subspecies (TPA, TPE and TEN). Results of this multilocus analysis divided syphilitic isolates into two groups: SS14-like and Nichols-like. The SS14-like group is comprised of SS14, Grady, Mexico A and Philadelphia 1 strains. The Nichols-like group consisted of strains Nichols, Bal 73-1, DAL-1, MN-3, Philadelphia 2, Haiti B and Madras. The TP0558 locus was selected for further studies because it clearly distinguished between the SS14- and Nichols-like groups and because the phylogenetic tree derived from the TP0558 locus showed the same clustering pattern as the tree constructed from whole genome sequences. In addition, TP0558 was shown as the only tested locus that evolved under negative selection within TPA strains. Sequencing of a short fragment (573 bp) of the TP0558 locus in a set of 25 clinical isolates from 22 patients collected in the Czech Republic during 2012-2013 revealed that clinical isolates follow the SS14- and Nichols-like distribution. [ABSTRACT FROM AUTHOR]

Abstract: The behaviour of Tidal Stream Turbines (TST) in the dynamic flow field caused by waves and rotor misalignment to the incoming flow (yaw) is currently unclear. The dynamic loading applied to the turbine could drive the structural design of the power capture and support subsystems, device size and its proximity to the water surface and sea bed. In addition, the strongly bi-directional nature of the flow encountered at many tidal energy sites may lead to devices omitting yaw drives; accepting the additional dynamic loading associated with rotor misalignment and reduced power production in return for a reduction in device capital cost. Therefore it is imperative to quantify potential unsteady rotor loads so that the TST device design accommodates the inflow conditions and avoids an unacceptable increase in maintenance action or, more seriously, suffers sudden structural failure. The experiments presented in this paper were conducted using a 1:20th scale 3-bladed horizontal axis TST at a large towing tank facility. The turbine had the capability to measure rotor thrust and torque whilst one blade was instrumented to acquire blade root strain, azimuthal position and rotational speed all at high frequency. The maximum out-of-plane bending moment was found to be as much as 9.5 times the in-plane bending moment. A maximum loading range of 175% of the median out-of-plane bending moment and 100% of the median in-plane bending moment was observed for a turbine test case with zero rotor yaw, scaled wave height of 2 m and intrinsic wave period of 12.8 s. A new tidal turbine-specific Blade-Element Momentum (BEM) numerical model has been developed to account for wave motion and yawed flow effects. This model includes a new dynamic inflow correction which is shown to be in close agreement with the measured experimental loads. The gravitational component was significant to the experimental in-plane blade bending moment and was also included in the BEM model. Steady loading on an individual blade at positive yaw angles was found to be negligible in comparison to wave loading (for the range of experiments conducted), but becomes important for the turbine rotor as a whole, reducing power capture and rotor thrust. The inclusion of steady yaw effects (using the often-applied skewed axial inflow correction) in a BEM model should be neglected when waves are present or will result in poor load prediction reflected by increased loading amplitude in the 1P (once per revolution) phase. [Copyright &y& Elsevier]

Abstract: Syphilis gained notoriety in the 1500s, when it became widespread throughout Europe. While the origins of syphilis are not certain, recent data have shown that it may have originated in the Americas from a close relative that causes Yaws (Treponema pallidum pertenue). 1 For the past 500years, the disease has shown its various faces all over the world. The 19th century saw an entire medical subspecialty—syphilology (sometimes known as syphilography)—devoted to the study of the great disease, then known as “the great imitator.” Syphilis has an entire textbook of presentations and can mimic many other infections and immune-mediated processes. At the beginning of the 20th century, the many faces of the disease led to Sir William Osler’s well-known aphorism, “The physician who knows syphilis knows medicine."2 When penicillin was discovered, and used to treat syphilis in 1943, some thought that syphilis would go by the wayside, but syphilis continued what it has been doing for so many years . . . inconspicuously infecting humans. The United States has seen the incidence of syphilis increase numerous times throughout the past 70years. Every decrease in the incidence of syphilis is followed shortly by an increase. A marked shift in the epidemiology occurred from 1990 to 2000. In the 1990s, syphilis primarily occurred in heterosexual minority groups. In the new millennium, a majority of cases of syphilis are now transmitted among men who have sex with men (MSM).3 This contribution discusses the incidence of syphilis in the United States and the reasons these trends continue. [Copyright &y& Elsevier]

Highlights: [•] The forced oscillation apparatus designed for the dynamic wind tunnel experiment is presented. [•] A model is forced to oscillate with angular oscillation around its transversal axis (pitch or yaw). [•] High loads and limited space inside a wind tunnel model caused the use of a hydraulic drive. [•] Significant improvement is achieved by using the semiconductor strain gauges on the sensors. [•] All sensors on the apparatus enable measurements of very small amplitudes of the excitation moment. [Copyright &y& Elsevier]

Abstract: The amplified resonance called catastrophic yaw can be associated to large amplitude equilibrium points of slightly asymmetric spinning cruciform missiles. The steady-state equations of motion in body fixed system of axes permit the analysis of the equilibrium points that define the long-term behavior of the missile in order to avoid this flight condition. This paper presents the fundamental analysis of a simplified nonlinear model of motion capable of exhibiting this flight condition. The model can be used to derive the conservative design condition that assures the low amplitude of the single equilibrium point. [Copyright &y& Elsevier]

Abstract: A neglected disease with a nearly forgotten name is making a comeback following a global control programme that almost eradicated it more than forty years ago. Until the 1970s the prevalence of non-venereal treponematosis, including yaws, was greatly reduced after worldwide mass treatment. In 2005, cases were again reported in the Democratic Republic of the Congo. A deterministic model is formulated to investigate the impact of poverty on yaws eradication. Threshold parameters are determined and stabilities analysed. The reproductive number was also used to assess the impact of birth rate in resource-constrained families on the dynamics of yaws. The model was shown to be globally stable whenever the associated reproductive number is less than a unity. Using the Lyapunov function it was proved that whenever the associated reproductive number is greater than a unity an endemic equilibrium exists and is globally asymptotically stable. Results from this theoretical study suggests that if the population of children in the community is dominated by those from resource-constrained families, then yaws eradication will remain difficulty to attain. Thus, more needs to be done in addressing issues such as high fertility rate, overcrowding, poor sanitation, etc. and poverty in general so that yaws epidemic which was successfully controlled several decades ago will cease to reemerge and can easily be eradicated. [Copyright &y& Elsevier]

Summary Objective To describe the recalled medical history, clinical manifestations, and treatment of yaws and syphilis by syphilis seroreactive blood donors in Kumasi, Ghana. Methods Of the blood donors at Komfo Anokye Teaching Hospital, Kumasi, Ghana tested with the syphilis rapid diagnostic test (RDT) and later by rapid plasma reagin (RPR) test, 526 were seroreactive. Four hundred and seventy-one (89.5%) of these subjects were confirmed with the Ortho-Vitros Syphilis TP test as the gold standard and were interviewed to determine past or present clinical manifestations of yaws and syphilis. Results Of the 471 respondent donors, 28 (5.9%) gave a history of skin lesions and sores; four (14.3%) of these subjects, who were all male and RPR-positive, recalled a diagnosis of syphilis. All four reported having had skin lesions/bumps with slow-healing sores, but only one of them had had these symptoms before the age of 15 years. Conclusions A small proportion of confirmed seroreactive donors in this sample had any recall of symptoms or treatment for yaws or syphilis. These data suggest that clinical questioning adds little further information to the current screening algorithm. The relative contribution of yaws and syphilis to frequent positive tests in endemic areas remains speculative. [ABSTRACT FROM AUTHOR]

Treponemal diseases comprise venereal syphilis (Treponema pallidum subsp. pallidum) and the endemic (non-venereal) treponematoses, i.e. yaws (T. pallidum subsp. pertenue), endemic syphilis (T. pallidum subsp. endemicum) and pinta (T. carateum). Treponemal diseases are distinguished on the basis of epidemiological characteristics and clinical manifestations. They are at present indistinguishable by morphological, immunological or serological methods. Several minor genetic differences have been identified among the subspecies. The endemic treponematoses have not yet been eliminated and are currently thought to affect at least 2.5 million persons. Renewed action towards the elimination of these diseases should be undertaken. [Copyright &y& Elsevier]