Does Carrying a Rider Change Motor and Sensory Laterality in Horses?

Laterality in horses has been studied in recent decades. Although most horses are kept for riding purposes, there has been almost no research on how laterality may be affected by carrying a rider. In this study, 23 horses were tested for lateral preferences, both with and without a rider, in three different experiments. The rider gave minimal aids and rode on a long rein to allow the horse free choice. Firstly, motor laterality was assessed by observing forelimb preference when stepping over a pole. Secondly, sensory laterality was assessed by observing perceptual side preferences when the horse was confronted with (a) an unfamiliar person or (b) a novel object. After applying a generalised linear model, this preliminary study found that a rider increased the strength of motor laterality (p = 0.01) but did not affect sensory laterality (p = 0.8). This suggests that carrying a rider who is as passive as possible does not have an adverse effect on a horse's stress levels and mental state.

Laterality in Horse Training: Psychological and Physical Balance and Coordination and Strength Rather Than Straightness.

For centuries, a goal of training in many equestrian disciplines has been to straighten the horse, which is considered a key element in achieving its responsiveness and suppleness. However, laterality is a naturally occurring phenomenon in horses and encompasses body asymmetry, motor laterality and sensory laterality. Furthermore, forcibly counterbalancing motor laterality has been considered a cause of psychological imbalance in humans. Perhaps asymmetry and laterality should rather be accepted, with a focus on training psychological and physical balance, coordination and equal strength on both sides instead of enforcing "straightness". To explore this, we conducted a review of the literature on the function and causes of motor and sensory laterality in horses, especially in horses when trained on the ground or under a rider. The literature reveals that body asymmetry is innate but does not prevent the horse from performing at a high level under a rider. Motor laterality is equally distributed in feral horses, while in domestic horses, age, breed, training and carrying a rider may cause left leg preferences. Most horses initially observe novel persons and potentially threatening objects or situations with their left sensory organs. Pronounced preferences for the use of left sensory organs or limbs indicate that the horse is experiencing increased emotionality or stress, and long-term insufficiencies in welfare, housing or training may result in left shifts in motor and sensory laterality and pessimistic mentalities. Therefore, increasing laterality can be regarded as an indicator for insufficiencies in housing, handling and training. We propose that laterality be recognized as a welfare indicator and that straightening the horse should be achieved by conducting training focused on balance, coordination and equal strength on both sides.

Probable aerosol transmission of SARS-CoV-2 in a poorly ventilated courtroom.

There is increasing evidence of SARS-CoV-2 transmission via aerosol; the number of cases of transmission via this route reported in the literature remains however limited. This study examines a case of clustering that occurred in a courtroom, in which 5 of the 10 participants were tested positive within days of the hearing. Ventilation loss rates and dispersion of fine aerosols were measured through CO2 injections and lactose aerosol generation. Emission rate and influencing parameters were then computed using a well-mixed dispersion model. The emission rate from the index case was estimated at 130 quanta h-1 (interquartile (97-155 quanta h-1 ). Measured lactose concentrations in the room were found relatively homogenous (n = 8, mean 336 µg m-3 , SD = 39 µg m-3 ). Air renewal was found to play an important role for event durations greater than 0.5 h and loss rate below 2-3 h-1 . The estimated emission rate suggests a high viral load in the index case and/or a high SARS-CoV-2 infection coefficient. High probabilities of infection in similar indoor situations are related to unfavorable conditions of ventilation, emission rate, and event durations. Source emission control appears essential to reduce aerosolized infection in events lasting longer than 0.5 h.

Vertical root fractures in crowned teeth: a report of 32 cases.

OBJECTIVE: To clarify the mode of root fracture in 32 endodontically treated teeth that resulted in vertical root fracture (VRF) despite the provision of a crown for fracture prevention. METHOD AND MATERIALS: The teeth included in the study underwent root canal treatment and were restored with crowns without the use of an intracanal post. All teeth underwent photo documentation. Clinical signs and symptoms as well as the patients' ages were recorded. The diameters of the roots and the root canal fillings were measured on radiographs. Fractured roots were investigated using a scanning electron microscope (SEM). RESULTS: The mean patient age was 60.2 years. The VRFs in the group occurred most frequently in the mesial roots of the mandibular first molars. The fracture was predominantly buccolingual. The mean ratio measured between the diameters of the root canal obturations and the outer root surfaces in the radiographs was 33.2%. SEM evaluation showed that most fractures ran from the inner to the outer root surface, and the cracks predominantly ran apical to coronal. CONCLUSION: Endodontically treated and crowned teeth without root canal posts can develop VRFs. The cracks start at the root canal wall in the apical part of the root and extend toward the outer root surface and coronally. Further investigation is necessary to determine the possible causes and evidence of fracture development.

Reconstruction of a mandibular defect with autogenous, autoclaved bone grafts and tissue engineering: An in vivo pilot study.

Reconstruction of bone defects with autogenous, autoclaved bone grafts has already been described but does have one major insuperable problem-the loss of the ostoinductive potential of the graft. In this study, we investigated if autogenous, autoclaved grafts in combination with tissue engineered bone can overcome this problem. An en-bloc resection was done in the mandible of eight pigs. The grafts were autoclaved and filled with autogenous, osseogen differentiated bone marrow cells and compared with four animals without bone marrow cells. After 120 days, the specimens were qualitatively and quantitatively evaluated by means of microradiography and light microscopy. Within the experimental group, osseous remodeling was detected in all cases and new bone formation was visible. Quantitative assessment of the osseous bridging of the osteotomy sites was significantly higher in the test group in comparison with the control group (p = 0.03). The histological evaluation by means of an osseous integration of the grafts revealed a statistically significant difference between both groups as well (p = 0.01). The results of this study indicate that the method investigated hereby represents a further possibility in the therapy of bony defects, such as those arising as a result of tumor operations.