Papers by Joshua G Davimes
Annals of anatomy, Apr 1, 2024
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Legal medicine, May 1, 2024
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Surgical and Radiologic Anatomy, Aug 21, 2023
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Annals of Anatomy - Anatomischer Anzeiger, Dec 31, 2023
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IBRO Neuroscience Reports
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Translational Research in Anatomy, Dec 31, 2023
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Asian Spine Journal
Study Design: A descriptive cross-sectional study of the anatomical variations, morphometry, and ... more Study Design: A descriptive cross-sectional study of the anatomical variations, morphometry, and histology of the iliolumbar veins (ILVs).Purpose: This study aimed to describe the anatomical variations of the ILVs and determine their tissue composition in South African cadavers of European descent.Overview of Literature: A safe anterior surgical approach to the L4/L5 intervertebral disc space requires understanding the anatomy of the ILVs. Limited understanding of ILVs and their variations may lead to inadvertent avulsion of veins with subsequent hemorrhage and damage to the adjacent nerves intraoperatively. Variations in ILVs are population specific, but such reports are limited in the South African population.Methods: Eighty-nine adult cadavers were dissected to reveal ILV patterns. The variations (origin, course, and drainage pattern), morphometries, and topography of the ILVs were studied. A total of 19 (10 proximal, nine distal) ILVs were processed for hematoxylin and eosin, Ma...
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Full dataset is located at http://wiredspace.wits.ac.za/handle/10539/29924. The human face is imp... more Full dataset is located at http://wiredspace.wits.ac.za/handle/10539/29924. The human face is important in social, cultural and recognition contexts. Many research fields make use of faces to understand human interaction and identify individuals. Studies relying on facial image data often make use of ad hoc datasets specifically created for those studies as there is a dearth of large scale controlled and matching facial image databases. Actualistic (taken in a real life, natural setting) and standardised databases of facial images can be of extreme value to many research areas, such as facial identification and recognition. While multiple face databases are available, the majority, if not all, are developed in order to address very specific questions and hypotheses with limited standardisation, severely limiting their potential applicability. The Wits Face Database was developed as a generic, yet actualistic dataset of facial images obtained from consenting young adult South African...
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F1000Research, 2021
Forensic facial comparison is a commonly used, yet under-evaluated method employed in medicolegal... more Forensic facial comparison is a commonly used, yet under-evaluated method employed in medicolegal contexts across the world. Testing the accuracy and reliability of facial comparisons requires large scale controlled and matching facial image databases. Databases that contain images of individuals on closed-circuit television (CCTV), with matching formal and informal photographs are needed for this type of research. Although many databases are available, the majority if not all are developed in order to improve facial recognition and face detection algorithms through machine learning, with very limited if any measure of standardisation. This paper aims to review the available databases and describe the development of a high resolution, standardised facial photograph and CCTV recording database of male Africans. The database is composed of a total of 6220 standardised and uncontrolled suboptimal facial photographs of 622 matching individuals in five different views, as well as corresp...
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The evolution and function of sleep remains an enigma in modern science. Significant variation ca... more The evolution and function of sleep remains an enigma in modern science. Significant variation can be observed within species and across taxa. Little is understood about how sleep exists, or presents itself in species surviving in extreme conditions. For example, harsh desert ecosystems with notably lower survival rates for resident species. It has been hypothesized that specialized sleep-related behaviours impact thermoregulation to promote survival advantage. The threatened Arabian oryx (Oryx leucoryx), a member of the Cetartiodactyl superorder, is a large desert dwelling ungulate species successfully residing in the arid zones of the Middle East. Arabian Oryx exhibit numerous morphophysiological adaptations and capabilities to cope with their harsh environment. The current thesis provides an examination of the neuroanatomy, physiology and behavioural patterns related to sleep in wild, free-roaming Arabian oryx under natural conditions. It was our objective to determine whether the extreme conditions and climate of the Arabian Desert has led to novelties within the organization of the oryx’s sleep related neuronal architecture, seasonal behaviour patterns and sleep physiology. Using immunohistochemistry and stereology our results indicate the sleep related nuclei in the brain of the oryx exhibit a typical mammalian organizational plan with additional order-specific and novel, species- specific features. Actigraphy revealed that oryx exhibit temporal niche switching patterns seasonally presenting with winter diurnal- and summer nocturnal activity and intermittent patterns during the transitional periods of spring and autumn. Polysomnography results indicate novel sleep patterns between seasons and physiologically confirm activity-based temporal niche switching at a seasonal level. Our work covers the first examination of the Arabian oryx brain sleep centers as well as its year-long activity patterns. Importantly, it is the first examination of physiological sleep in wild mammals within a desert environment. Our results suggest that ambient temperature acts a dominant driving force for the adaptive behavioural and physiological features described. The Arabian oryx is a remarkable species, well adapted to such an extreme environment and its highly plastic survival mechanisms appear unique. Considering the continual desertification of our planet and the predicted consequences of climate change, knowledge of such species and their continued conservation is of vital importance.
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Journal of Neurochemistry
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Surgical and Radiologic Anatomy
The sternalis muscle is an infrequent, non-pathological anatomical variant typically misrepresent... more The sternalis muscle is an infrequent, non-pathological anatomical variant typically misrepresented in a clinical context. It presents with 3–8% prevalence, according to cadaveric studies. The muscles were identified during routine cadaver prosection at the School of Anatomical Sciences, University of the Witwatersrand. Here, we report two cases of the sternalis muscle in two South African White cadavers. Analysis of the sternalis muscles revealed unilaterally present, distinctly defined muscle masses on the right (case number 1, female) and left (case number 2, male) hemithorax, lateral to the sternum. The muscles occurred with a prevalence of 2.25% within the cadaveric population examined. The prevalence of the sternalis muscle is generally low, especially in the European population. Their presence represents the remnants of the cutaneous muscles in the ventral thorax of lower animals. Clinically, the sternalis muscle may be misinterpreted as a pathological mass or lesion, thus accurate knowledge regarding its variations and prevalence is of importance.
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Transactions of the Royal Society of South Africa
The hand metrics of Palaeolithic artists show a number of distinctive features that contrast with... more The hand metrics of Palaeolithic artists show a number of distinctive features that contrast with the low-variance hand metrics of modern Europeans, and with the majority of other modern humans. For example, the D2/D4 ratio in the Palaeolithic artists has a much greater spread of values and a greater degree of sexual dimorphism. We find that living San people, who represent the minority of modern humans that have high-variance genetics, also have a hand metric phenotype like the Palaeolithic artists, different from modern Europeans and other low-variance genetics modern humans. The increased variance and sexual dimorphism of the phenotypic D2/D4 ratio in the San measurements are in keeping with genetic evidence that the San represent one of the oldest human lineages with the greatest genetic diversity. The findings have the implication that the European Palaeolithic cave artists may have been derived from San-like migrants who brought an established artistic tradition from Africa to Europe, only to be replaced as a population, leaving no evidence of their genetics in modern Europeans, as observed for other Palaeolithic genes such as Oase 1.
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Journal of biological rhythms, Aug 6, 2016
The Arabian oryx inhabits an environment where summer ambient temperatures can exceed 40 °C for e... more The Arabian oryx inhabits an environment where summer ambient temperatures can exceed 40 °C for extended periods of time. While the oryx uses a suite of adaptations that aid survival, the effects of this extreme environment on inactivity are unknown. To determine how the oryx manages inactivity seasonally, we measured the daily rhythm of body temperature and used fine-grain actigraphy, in 10 animals, to reveal when the animals were inactive in relation to ambient temperature and photoperiod. We demonstrate that during the cooler winter months, the oryx was inactive during the cooler parts of the 24-h day (predawn hours), showing a nighttime (nocturnal) inactivity pattern. In contrast, in the warmer summer months, the oryx displayed a bimodal inactivity pattern, with major inactivity bouts (those greater than 1 h) occurring equally during both the coolest part of the night (predawn hours) and the warmest part of the day (afternoon hours). Of note, the timing of the daily rhythm of bo...
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Biology
Global escalation of crime has necessitated the use of digital imagery to aid the identification ... more Global escalation of crime has necessitated the use of digital imagery to aid the identification of perpetrators. Forensic facial comparison (FFC) is increasingly employed, often relying on poor-quality images. In the absence of standardized criteria, especially in terms of video recordings, verification of the methodology is needed. This paper addresses aspects of FFC, discussing relevant terminology, investigating the validity and reliability of the FISWG morphological feature list using a new South African database, and advising on standards for CCTV equipment. Suboptimal conditions, including poor resolution, unfavorable angle of incidence, color, and lighting, affected the accuracy of FFC. Morphological analysis of photographs, standard CCTV, and eye-level CCTV showed improved performance in a strict iteration analysis, but not when using analogue CCTV images. Therefore, both strict and lenient iterations should be conducted, but FFC must be abandoned when a strict iteration pe...
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IBRO Neuroscience Reports
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The Anatomical Record
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Journal of chemical neuroanatomy, Apr 1, 2017
The Arabian oryx, Oryx leucoryx, is a member of the superorder Cetartiodactyla and is native to t... more The Arabian oryx, Oryx leucoryx, is a member of the superorder Cetartiodactyla and is native to the Arabian Desert. The desert environment can be considered extreme in which to sleep, as the ranges of temperatures experienced are beyond what most mammals encounter. The current study describes the nuclear organization and neuronal morphology of the systems that have been implicated in sleep control in other mammals for the Arabian oryx. The nuclei delineated include those revealed immunohistochemically as belonging to the cholinergic, catecholaminergic, serotonergic and orexinergic systems within the basal forebrain, hypothalamus, midbrain and pons. In addition, we examined the GABAergic neurons and their terminal networks surrounding or within these nuclei. The majority of the neuronal systems examined followed the typical mammalian organizational plan, but some differences were observed: (1) the neuronal morphology of the cholinergic laterodorsal tegmental (LDT) and pedunculopontin...
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Sleep, 2018
Study Objectives
The Arabian oryx lives under hyperarid conditions in the Arabian Desert and exhi... more Study Objectives
The Arabian oryx lives under hyperarid conditions in the Arabian Desert and exhibits temporal niche switching of activity patterns at a seasonal level. The objective of the current study was to provide a polysomnographic-based study of sleep in free-roaming Arabian oryx in their natural habitat to determine whether extreme seasonal climate variations resulted in changes in sleep patterns and physiology associated with the seasonal switching of temporal niches.
Methods
Electroencephalography, nuchal electromyography, actigraphy, and subcutaneous temperature were recorded in free-roaming Arabian oryx in the Mahazat as-Sayd Protected Area, Kingdom of Saudi Arabia during winter and summer.
Results:
Total daily sleep time in winter was 6.69 and 3.77 hr in summer. In winter, oryx exhibited nocturnal sleep typical of artiodactyls of around 60 kg body mass. In summer, oryx slept mostly during the day and subcutaneous temperature was seen to rise during sleep, but not as rapidly as the rises observed in ambient air temperature. Rapid eye movement sleep formed a very small percentage of total sleep time, especially so in the summer.
Conclusions
The unusual sleep patterns and physiology during summer appear to be related to high ambient air temperatures that affect both intrinsic and extrinsic factors necessary for survival. The Arabian oryx appears to use sleep physiology as an adaptive thermoregulatory mechanism in the hot summer months.
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Physiology & behavior, Jan 18, 2017
The Arabian oryx, a moderately large mammal that inhabits a harsh desert environment, has been sh... more The Arabian oryx, a moderately large mammal that inhabits a harsh desert environment, has been shown to exhibit seasonal variations in activity and inactivity patterns. Here we analyzed the continuous year-round activity patterns of twelve free-roaming Arabian oryx under natural conditions from two varying desert environments in Saudi Arabia using abdominally implanted activity meters. We simultaneously recorded weather parameters at both sites to determine whether environmental factors are responsible for temporal niche switching as well as the seasonal structuring and timing of this behavioural plasticity. Our results demonstrate that Arabian oryx undergo temporal niche switching of 24 h activity patterns at a seasonal level and exhibit distinct nocturnal/crepuscular activity during summer, diurnal activity during winter and intermittent patterns of behaviour during the transitional seasons of autumn and spring. In addition, the oryx exhibited inter- and intra-seasonal variations in the temporal budgeting of 24 h activity patterns. Strong relationships with both photoperiod and ambient temperatures were found and in some instances suggested that increasing ambient temperatures are a primary driving force behind seasonal shifts in activity patterns. These adaptive patterns may be dictated by the availability of food and water, which in turn are strongly influenced by seasonal climate variations. Overall, the adaptive responses of free-roaming Arabian oryx in such harsh and non-laboratorial conditions provide a framework for comparing wild populations as well as aiding conservation efforts.
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Papers by Joshua G Davimes
The Arabian oryx lives under hyperarid conditions in the Arabian Desert and exhibits temporal niche switching of activity patterns at a seasonal level. The objective of the current study was to provide a polysomnographic-based study of sleep in free-roaming Arabian oryx in their natural habitat to determine whether extreme seasonal climate variations resulted in changes in sleep patterns and physiology associated with the seasonal switching of temporal niches.
Methods
Electroencephalography, nuchal electromyography, actigraphy, and subcutaneous temperature were recorded in free-roaming Arabian oryx in the Mahazat as-Sayd Protected Area, Kingdom of Saudi Arabia during winter and summer.
Results:
Total daily sleep time in winter was 6.69 and 3.77 hr in summer. In winter, oryx exhibited nocturnal sleep typical of artiodactyls of around 60 kg body mass. In summer, oryx slept mostly during the day and subcutaneous temperature was seen to rise during sleep, but not as rapidly as the rises observed in ambient air temperature. Rapid eye movement sleep formed a very small percentage of total sleep time, especially so in the summer.
Conclusions
The unusual sleep patterns and physiology during summer appear to be related to high ambient air temperatures that affect both intrinsic and extrinsic factors necessary for survival. The Arabian oryx appears to use sleep physiology as an adaptive thermoregulatory mechanism in the hot summer months.
The Arabian oryx lives under hyperarid conditions in the Arabian Desert and exhibits temporal niche switching of activity patterns at a seasonal level. The objective of the current study was to provide a polysomnographic-based study of sleep in free-roaming Arabian oryx in their natural habitat to determine whether extreme seasonal climate variations resulted in changes in sleep patterns and physiology associated with the seasonal switching of temporal niches.
Methods
Electroencephalography, nuchal electromyography, actigraphy, and subcutaneous temperature were recorded in free-roaming Arabian oryx in the Mahazat as-Sayd Protected Area, Kingdom of Saudi Arabia during winter and summer.
Results:
Total daily sleep time in winter was 6.69 and 3.77 hr in summer. In winter, oryx exhibited nocturnal sleep typical of artiodactyls of around 60 kg body mass. In summer, oryx slept mostly during the day and subcutaneous temperature was seen to rise during sleep, but not as rapidly as the rises observed in ambient air temperature. Rapid eye movement sleep formed a very small percentage of total sleep time, especially so in the summer.
Conclusions
The unusual sleep patterns and physiology during summer appear to be related to high ambient air temperatures that affect both intrinsic and extrinsic factors necessary for survival. The Arabian oryx appears to use sleep physiology as an adaptive thermoregulatory mechanism in the hot summer months.
sleep in wild mammals within a desert environment. Our results suggest that ambient temperature acts a dominant driving force for the adaptive behavioural and physiological features described. The Arabian oryx is a remarkable species, well adapted to such an extreme environment and its highly plastic survival mechanisms appear unique. Considering the continual desertification of our planet and the predicted consequences of climate change, knowledge of such species and their continued conservation is of vital importance.