Does ABS ensure good performance in emergency braking for less skilled motorcyclists?

This study aims to investigate whether motorcyclists are able to use the full potential of anti-lock braking systems (ABS) in demanding braking situations that maintain the natural coupling of action and perception of emergency events, or whether instead the lack of braking skills in riders makes ABS almost ineffective and comparable to non-ABS brakes on dry pavement. Six experienced riders performed two experimental tests. First test included 12 emergency braking trials in a realistic scenario using a mock-up of an intersection conflict with a car initiating a left turn manoeuvre across the path (LTAP) of a motorcycle approaching from the opposite direction as an unpredicted moving hazard. Second test included three trials in a planned self-timed hard braking. The speed at the onset of braking was 35-45 km/h. The braking performance was measured from the initiation of brake pressure until the full stop of the vehicle. Front wheel ABS usage was determined by the pressure in the master cylinder and wheel callipers. The testing resulted in 85 data runs with full stop braking manoeuvres. Results revealed four categories of riders classified by their front wheel ABS usage during the emergency braking tests, which included two riders who underused front wheel ABS (9.6% and 27.4% of braking time on average). The worst case resulted in a significantly longer braking distance (braking deceleration of 5.2 m/s2). The highest skilled rider, who reached initial jerks close to 30 m/s3, used the ABS of the front wheel 93.7% of the braking time on average, resulting in a braking deceleration of 7.71 m/s2. Overall, the best braking performance was achieved in trials where the front ABS was activated for more than 80% of the braking. In planned self-timed hard braking test, where riders have more time to plan the braking manoeuvre, the experience rider with lowest performance during the emergency braking test improved braking efficiency and was able to increase ABS activation from 9.6% to 26.8% of the time, achieving a deceleration of 6.24 m/s2. ABS is demonstrated to reduce stopping distances and to improve stability under all braking conditions, but such features are not enough to guarantee a good braking performance in emergency events if the riders have not the skills to utilize the full braking power of the motorcycle. Less skilled riders, even with ABS, may not have the confidence to increase braking power further when reaching high decelerations that push them to the limit of their stabilisation control in emergency braking, thus increasing braking distance with potentially life-threatening consequences. Our results suggest that many experience riders still need knowledge and skill to make the ABS work to its optimum in emergency events to avoid crashes. Further research with larger sample sizes including the full diversity of the motorcyclist population is recommended to determine the actual proportion of motorcyclists underusing ABS.

Orthognathic surgery and aligners. A comparative assessment of periodontal health and quality of life in postsurgical orthodontic treatment with aligners versus traditional fixed appliances: a randomized controlled trial.

BACKGROUND: Removable clear aligners have become very popular in the last few decades, but they are still little used in the field of orthognathic surgery (OS). The objective of this study was to compare periodontal health and quality of life (QoL) associated to postsurgical orthodontic treatment. MATERIAL AND METHODS: Patients with dentofacial deformities undergoing OS were randomly allocated to receive postsurgical orthodontic treatment with either fixed orthodontic appliances or Invisalign. The main outcomes were periodontal health and QoL. Plaque index, probing depth and bleeding on probing were assessed as periodontal health indicators. QoL was assessed through the Orthognathic Quality of Life Questionnaire (OQLQ-22) and the Oral Health Impact Profile (OHIP-14). Data were analyzed before surgery and end of treatment. Total duration of treatment was also recorded. RESULTS: Twenty-eight patients were randomized, (16 women, 12 men). Periodontal assessment showed better outcomes for the Invisalign group: bleeding on probing (p=0.013), plaque index (p=0.001) and probing depth (p<0.001). The QoL questionnaires showed significant differences in favor of the Invisalign group: OHIP-14 (p=0.004) and OQLQ-22 (p=0.002). Total duration of treatment was similar in both groups (p=0.575). CONCLUSIONS: Compared to traditional orthodontics with fixed appliances, patients managed with clear aligners after OS (surgery-first approach) had better periodontal health and QoL outcomes.

The combined coronal-transconjunctival approach: an innovative surgical access for orbital exenteration in craniofacial resection.

Malignant tumours arising in the paranasal sinuses or maxilla usually spread to the surrounding regions. The skull base and the anterior cranial fossa are frequently affected as well. When the resection of a tumour involves an orbital exenteration, a transconjunctival-perilimbic incision can be added to a coronal approach in order to preserve the eyelids and the conjunctiva, avoiding cutaneous midfacial incisions. Patients with a diagnosis of malignant tumour affecting the orbit, upper jaw, paranasal sinuses, and/or anterior skull base were eligible for this technique. Tumoural invasion of the eyelids, conjunctiva, lacrimal system, or surrounding skin was considered a contraindication for this technique. A retrospective study of the clinical records was performed and age, type of tumour, location, and reconstructive technique were evaluated. Eight patients referred to the study department between 2015 and 2019 were selected. All patients underwent craniofacial surgery and orbital exenteration. The transconjunctival-perilimbic approach was combined with a coronal incision in all cases. In our experience, the transconjunctival-perilimbic approach to orbital exenteration proposed in this paper can be used successfully in skull base surgery. Combined with a coronal and transmandibular approach, it allows wide access to the facial skeleton/anterior skull base while avoiding skin incisions in the midface.

Development and Psychometrics of Instruments to Assess School Personnel's Bystander Action in Situations of Teen Relationship Abuse and Sexual Assault.

This article describes recently developed instruments that assess school personnel's bystander barriers and intentions in situations of teen relationship abuse, sexual assault, and sexual harassment, as well as perceptions of school readiness specific to relationship abuse, sexual assault, and sexual harassment prevention and response. Participants were 1,150 high school personnel from 25 schools in New Hampshire, Massachusetts, and Maine. Specific instruments focused on bystander intentions, bystander action, barriers to bystander action, and perceptions of school readiness. Participants were randomly divided into two groups for analysis-the exploratory sample (ES; n = 575) and the confirmatory sample (CS; n = 575). Overall, the measures demonstrated acceptable fit indices. Results suggested that most measures and subscales had adequate reliability, but a few subscales had less than ideal internal consistency, which can likely be attributed to the small number of items. More work is needed, but these measures act as a starting point by which the role of school personnel in prevention initiatives and bystander intervention can be evaluated.

Measurement Tools to Assess Relationship Abuse and Sexual Assault Prevention Program Effectiveness Among Youth.

OBJECTIVE: This article describes the adaptation, development, and psychometric properties of survey instruments to assess outcomes of bystander-focused violence prevention efforts among high school students, including media literacy, rape myths, bystander readiness, bystander barriers and facilitators of bystander action, bystander intentions, perceptions of school personnel helping, perceptions of peer helping, and victim empathy. METHOD: The study was based on data collected from 3,172 high school students across 25 schools in northern New England. RESULTS: Overall, the measures demonstrated acceptable fit indices in multilevel exploratory and confirmatory factor analyses. Whereas most measures and subscales had adequate reliability, several measures had less than ideal internal consistency, likely because of the limited number of items. CONCLUSION: Although additional measurement work is needed, these measures provide researchers and practitioners with foundational tools for basic research and program evaluation.

Study of guided wave propagation on a plate between two solid bodies with imperfect contact conditions.

In this work, fundamental symmetric Lamb wave S0 mode is characterized in terms of its velocity variation as function of the interfacial conditions between solid bodies in contact. Imperfect contact conditions are numerically and experimentally determined by using ultrasonic Lamb wave propagation parameters. For the study, an experimental system was used, formed by two solid aluminum rods (25.4mm in diameter) axially loading a thin aluminum plate to control contact interfacial stiffness. The axially applied load on the aluminum plate was varied from 0MPa to 10MPa. Experimental Lamb wave signals were excited on the plate through two longitudinal contact transducers (1MHz of central frequency) using a pitch-catch configuration. Numerical simulations of contact conditions and Lamb wave propagation were performed through Finite Element Analysis (FEA) in commercial software, ANSYS 15®. Simulated Lamb wave signals were generated by means of a 5 cycles tone burst signals with different frequency values. Results indicate a velocity change in both, experimental and simulated Lamb wave signals as function of the applied load. Finally, a comparison between numerical results and experimental measurements was performed obtaining a good agreement.

Antiferromagnetic-like coupling in the cationic iron cluster of thirteen atoms.

We explore, within the density functional theory in the generalized gradient approximation to exchange and correlation, the map of spin isomers of the cationic Fe13(+) cluster in connection with recent X-ray magnetic circular dichroism spectroscopy experiments [M. Niemeyer et al., Phys. Rev. Lett. 2012, 108, 057201] which showed an anomalous low magnetic moment per number of 3d holes in this cluster. We systematically explore the low-lying magnetic excitations and correlate them with structural rearrangements and stability indicators. We obtain the observed low magnetic moment per 3d hole as the ground state of Fe13(+) and we demonstrate that, as supposed by the experimentalists, the cluster undergoes a magnetic transition from a ferromagnetic-like configuration to an antiferromagnetic-like one upon ionization. We unravel this unexpected magnetic behavior showing that it is concomitant with a Th-deformation of the icosahedral structure together with the electronic filling of this particular iron cluster. The spin-orbit interaction preserves this magnetic configuration which is essentially due to the spin. Our computed magnetic anisotropy energy supports the experimental interpretation of the cluster as fluxional due to the very weak coupling of the magnetic moment to an easy axis.

Cervical necrotizing fasciitis and diabetic ketoacidosis: literature review and case report.

Necrotizing fasciitis (NF) is a rare polymicrobial infection that can be life-threatening. It is a rapidly progressive inflammatory process affecting the deep fascia, with secondary necrosis of the subcutaneous tissue. It is characterized by its fulminant course and its high mortality rate. Most cases of NF affect the abdomen, groin, and extremities. NF in the neck is reported to be rare and most cases are odontogenic in origin. Misdiagnosis and delayed treatment can result in death from sepsis, mediastinitis, carotid artery erosion, jugular vein thrombophlebitis, or aspiration pneumonia. The diagnosis is based on a combination of clinical history and predisposing factors, Gram staining and culture, imaging, and surgical exploration. Early and aggressive surgical treatment and intensive medical care are essential. The aim of this article is to report a case of severe and extensive cervical NF worsened by a diabetic ketoacidosis as a first appearance of diabetes mellitus.

Temperature-sensitive poly(N-isopropyl-acrylamide) microgel particles: a light scattering study.

We present a light scattering study of aqueous suspensions of microgel particles consisting of poly(N-Isopropyl-Acrylamide) cross-linked gels. The solvent quality for the particles depends on temperature and thus allows tuning of the particle size. The particle synthesis parameters are chosen such that the resulting high surface charge of the particles prevents aggregation even in the maximally collapsed state. We present results on static and dynamic light scattering (SLS/DLS) for a highly diluted sample and for diffuse optical transmission on a more concentrated system. In the maximally collapsed state the scattering properties are well described by Mie theory for homogenous hard spheres. Upon swelling we find that a radially inhomogeneous density profile develops.

Magnetic properties of a pair of V4 interacting clusters in a Fe matrix.

The magnetic properties of a pair V4 atomic clusters embedded in bulk Fe are determined by using a realistic spd-band Hubbard-like model. The spin density distribution is calculated self-consistenly in the unrestricted Hartree-Fock approximation. The local magnetic moments mu(i) are obtained at various atoms i of the cluster and of the surrounding Fe matrix. We consider two different geometrical arrangements for V clusters, collinear (C) and non-collinear (NC). In all the cases studied the magnetic coupling in the interface cluster-matrix is antiferromagnetic, and the ferromagnetic order of the matrix is not broken by the presence of the V atoms, although the local magnetic moments of Fe atoms at the interface cluster-matrix, are reduced respect to Fe bulk magnetization (2.22 microB) about 8%-20%. We compare the results with those of just one V4 atomic cluster embedded in bulk Fe.

Sero-prevalence of Taenia solium cysticercosis and Taenia solium taeniasis in California, USA.

OBJECTIVES: Taenia solium Cysticercosis is a leading cause of epilepsy and neurological disability in the developing world. It is caused by ingestion of the eggs of the tapeworm, T. solium Taeniasis. The prevalence of either T. solium Cysticercosis or T. solium Taeniasis in the United States in populations at risk is poorly understood. The primary objectives of this study are to perform the first study of the sero-prevalence of T. solium Cysticercosis and T. solium Taeniasis in an at-risk community in the USA, specifically rural Southern California; identify T. solium Taeniasis positive individuals, and treat positive individuals for the tapeworm T. solium Taeniasis. METHODS: Community based sero-prevalence study of antibodies to T. solium Cysticercosis and T. solium Taeniasis in 449 subjects living in a federally funded, predominantly Hispanic residential community; and in two migrant farm worker camps in rural Ventura County, California, USA. For this study, fingerstick blood samples were obtained. Serum immunoblots for both T. solium Cysticercosis and T. solium Taeniasis were performed. RESULTS: The sero-prevalence of T. solium Cysticercosis was 1.8% and the sero-prevalence of T. solium Taeniasis by serum immunoblot was 1.1%. Taenia solium Cysticercosis and T. solium Taeniasis antibodies were not detected in children. The sero-prevalence of T. solium Taeniasis was highest in the migrant farm worker community. Handwashing frequency was correlated with T. solium Taeniasis sero-positivity. CONCLUSION: The sero-prevalence of T. solium Cysticercosis and T. solium Taeniasis in this population, as detected by serum immunoblot, approximates the prevalence in some endemic areas of Latin America. Importantly, most patients likely had prior exposure, not active infection. This study establishes for the first time, the relative sero-prevalence of T. solium Cysticercosis and T. solium Taeniasis in at-risk populations in the United States.

[Dental caries in an animal model]. / Caries dental en un modelo animal.

Sprague-Dawley rats were inoculated with Streptococcus mutans (serotype g) and the effect of different concentrations (20, 40 and 56%) of sucrose in the diet on the establishment of this strain into the oral cavity of rats was studied. The Streptococcus mutans was well established in all the experimental groups and we found an almost linear correlation between the sucrose concentration and the severity of dental caries. Another factor that played an important role on the establishment of Streptococcus mutans into the mouth of rats was the inoculum size used. In this work a concentration of 4 x 10(10) showed a consistent establishment onto the teeth of this animal model.