General-purpose and special-purpose visual systems

The information that eyes supply supports a wide variety of functions, from the guidance systems that enable an animal to navigate successfully around the environment, to the detection and identification of predators, prey, and conspecifics. The eyes with which we are most familiar the single-chambered eyes of vertebrates and cephalopod molluscs, and the compound eyes of insects and higher crustaceans allow these animals to perform the full range of visual tasks. These eyes have evidently evolved in conjunction with brains that are capable of subjecting the raw visual information to many different kinds of analysis, depending on the nature of the task that the animal is engaged in. However, not all eyes evolved to provide such comprehensive information. For example, in bivalve molluscs we find eyes of very varied design (pinholes, concave mirrors, and apposition compound eyes) whose only function is to detect approaching predators and thereby allow the animal to protect itself by closing its shell. Thus, there are special-purpose eyes as well as eyes with multiple functions

The Operation of the Visual System in Relation to Action

Neurophysiologists studying the visual representation of the world in the parietal lobe generally find that it is based in a gaze-centred (retinotopic) frame. Students of orientation, however, find that the brain also contains a more panoramic egocentric representation that allows appropriate motor actions to take place independent of the orientation of the eyes and head. This representation can operate temporarily without visual input, but is updated from the vestibular system and from other modalities. In this minireview, I shall consider how these two representations are kept aligned with each other, and how they relate to the organisation of motor actions and to the phenomenal world that we see

Fairground rides and spatial updating

A simple experiment with a rotating office chair demonstrates that the extent of counter-rotation we experience when imposed rotation has stopped is the same as the angular inaccuracy of pointing to a previously fixated object. This suggests that our conscious percept of rotation and the updating signal for the egocentric model we use to guide motor actions are closely related

Detection of a Dipole in the Handedness of Spiral Galaxies with Redshifts z ~ 0.04

A preference for spiral galaxies in one sector of the sky to be left-handed or right-handed spirals would indicate a parity violating asymmetry in the overall universe and a preferred axis. This study uses 15158 spiral galaxies with redshifts <0.085 from the Sloan Digital Sky Survey. An unbinned analysis for a dipole component that made no prior assumptions for the dipole axis gives a dipole asymmetry of -0.0408\pm0.011 with a probability of occurring by chance of 7.9 x 10-4. A similar asymmetry is seen in the Southern Galaxy spin catalog of Iye and Sugai. The axis of the dipole asymmetry lies at approx. (l, b) =(52{\deg}, 68.5{\deg}), roughly along that of our Galaxy and close to alignments observed in the WMAP cosmic microwave background distributions. The observed spin correlation extends out to separations ~210 Mpc/h, while spirals with separations < 20 Mpc/h have smaller spin correlations.Comment: To be published in Physics Letters

Ways of seeing Visual Ecology Tom Cronin, Sönke Johnsen, Justin Marshall and Eric Warrant (Princeton University Press, Princeton, NJ; 2014) ISBN: 978-1-400853-021

Unknow

Methicillin-resistant Staphylococcus aureus prevalence: Current susceptibility patterns in Trinidad

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) has become one of the most widespread causes of nosocomial infections worldwide. Recently, reports have emerged that S. aureus strains recovered from community-acquired infections are also methicillin-resistant. This study was undertaken to analyze the prevalence of methicillin resistance among isolates at a regional hospital in Trinidad, and document the current resistance profile of MRSA and methicillin-sensitive Staphylococcus aureus (MSSA) to the commonly used anti-staphylococcal agents. METHODS: Over a 6-year period we analyzed 2430 isolates of S. aureus strains recovered from various clinical sources, from hospital and community practices. Antimicrobial susceptibility testing was done according to guideline recommendations of the National Committee for Clinical Laboratory Standards. RESULTS: The prevalence of MRSA from surgical/burn wounds, urine and pus/abscess were 60.1%, 15.5% and 6.6%, respectively. The major sources of MSSA were surgical/burn wounds, pus/abscess and upper respiratory tract specimens with rates of 32.9%, 17.1% and 14.3%, respectively. The greatest prevalence of resistance of MRSA was seen for erythromycin (86.7%), and clindamycin (75.3%). Resistance rates among MSSA were highest for ampicillin (70%). Resistance rates for tetracycline were similar among both MRSA (78.7%) and MSSA (73.5%). The MRSA recovery rates from nosocomial sources (20.8%) was significantly higher than that of previous years (12.5%) (p < 0.001), whereas rates among community isolates were relatively similar for the same period (4.1% versus 8.1%). CONCLUSION: The prevalence of MRSA in the hospital increased from 12.5% in 1999 to 20.8% in 2004. Most isolates were associated with infected surgical/burn wounds which may have become infected via the hands of HCPs during dressing exercises. Infection control measures aimed at the proper hand hygiene procedures may interrupt the spread of MRSA. HCPs may also be carriers of MRSA in their anterior nares. Surveillance cultures of both patients and HCPs may help to identify carriers who would be offered antibiotics to eradicate the organisms. Most MRSA are resistant to several non-β-lactam antibiotics. Frequent monitoring of susceptibility patterns of MRSA and the formulation of a definite antibiotic policy maybe helpful in decreasing the incidence of MRSA infection

Gross motor assessment tools for children 0-12 years of age using telehealth: a scoping review

Objective: The objective of this review was to understand the scope of evidence relating to the use of telehealth for gross motor assessment tools in children 0-12 years of age. Background: Telehealth has been widely used by physiotherapists since the start of the Covid-19 pandemic, however, little is known about the validity and reliability of using gross motor assessment tools via telehealth. Gross motor assessment tools are used by physiotherapists to understand motor function, support diagnoses of motor disorders, and plan and evaluate interventions. Qualitative research identifies a lack of confidence by physiotherapists in undertaking physical assessment via telehealth. Method: A comprehensive search was undertaken of MEDLINE, Scopus, CINAHL, Physiotherapy Evidence Database (PEDro) and OTseeker in August 2022. Grey searching was also implemented. Two independent reviewers identified articles for inclusion and critically appraised the articles. Data was analysed using a narrative review. Results: 34 studies met the inclusion criteria