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Scientific Reports Sep 2023Terror birds (Aves, Phorusrhacidae) comprise the most outstanding group of South American Cenozoic avifauna, and have been considered dominant predators. Terrestrial...
Terror birds (Aves, Phorusrhacidae) comprise the most outstanding group of South American Cenozoic avifauna, and have been considered dominant predators. Terrestrial habits were inferred using the reduction of their forelimbs and high body mass. Phorusrhacids were considered functionally tridactyl with three relatively short digits II-IV and a small, elevated digit I. The function of the ungual phalanges of digit II have been debated, including the utility of the ungual for retention or stabbing of prey. Incomplete or lack of preservation of foot bones have hampered understanding of the evolution and diversification of Phorusrhacidae. Here we show the first known and well-preserved footprints of Phorusrhacidae with a didactyl posture, which are named Rionegrina pozosaladensis igen. et isp. nov. These footprints yield unprecedented information on the locomotor habits of the group. The finding implies that medium-sized, Late Miocene (~ 8 Ma) phorusrhacids developed strong cursorial adaptations; achieved through reduction of digit II, raised metatarso-phalangeal pad, main body support in a large and thick digit III, and digit IV as outrigger. Raised and long claw of digit II was probably used in pining of prey. Phorusrhacid footprints differ from the Early Cretaceous didactyl footprints of deinonychosaurian dinosaur affinity by its larger size and strong mesaxony.
Topics: Animals; Fossils; Dinosaurs; Birds; Forelimb; Posture; Biological Evolution
PubMed: 37777554
DOI: 10.1038/s41598-023-43771-x -
Early Human Development Dec 2020Prenatal sex hormones may not exclusively determine effects of hand preference on digit ratios. Genetic determination is an alternative possibility.
BACKGROUND
Prenatal sex hormones may not exclusively determine effects of hand preference on digit ratios. Genetic determination is an alternative possibility.
AIM
To study the likelihood of similar effects of hand preference on digit lengths and digit ratios.
METHODS
We selected similar numbers of left-handers and right-handers in samples of kindergarten children (N = 101, age range: 3.5-7 years) and adults (N = 189, age range: 17-28 years) and measured digit lengths (excluding the thumb) directly on the palmar hand.
RESULTS
Compared to right-handers, left-handers had longer digits and lower third-to-fourth (3D:4D) digit ratios among children, whereas an opposite pattern of handedness differences occurred among adults.
CONCLUSIONS
Effects of hand preference on digit lengths and ratios might be genetically/ontogenetically determined. Also discussed are implications of this set of findings for digit ratio research.
Topics: Adolescent; Adult; Child; Child, Preschool; Female; Fingers; Functional Laterality; Humans; Male
PubMed: 33059164
DOI: 10.1016/j.earlhumdev.2020.105204 -
Zoology (Jena, Germany) Jun 2020This study considered possible sexual dimorphism in the relative lengths of the second, third and fourth digits (digit ratio), in calves. Furthermore, a different length...
This study considered possible sexual dimorphism in the relative lengths of the second, third and fourth digits (digit ratio), in calves. Furthermore, a different length of the bone structures of the third (3D) and of the fourth (4D) digits has been examined as an evolutionary adaptation to locomotion on soft ground. The length of the digital bones of the right fore-limb of 33 females and 15 male calves was measured in vivo using a portable X-ray machine. The vestigial structure of the second digit (2D), and 3D and 4D, from metacarpus to the third phalanx were considered in a mixed model, as well as some ratios between 2D and different parts of 3D or 4D (2D:3D and 2D:4D). A covariate for the mean finger length was considered for digit ratios to control for possible biases due to shape allometry. Shorter first phalanx and trotter were found in 3D than in 4D, and the reverse for the third phalanx. The 2D was significantly shorter in females, as well as the second phalanges of 3D and 4D. Significant sex differences in 2D:3D and 2D:4D were found for some digit parts of 3D and 4D and for the first phalanges of 3D:4D. These ratios were always shorter in females, in contrast to that found in most mammals. The asymmetry between 3D and 4D could mean a functional adaptation for locomotion. Sex differences in 2D:4D and 3D:4D were found, but with a reverse pattern than in most mammal species (males > females rather than males < females). In this regard digit ratio in calves was similar to that of Old World monkeys. This study is the first investigation of digit ratio in Ungulates, whose limbs differ from the limbs of most mammals, maintaining five digits. The reverse pattern of sex differences (digit ratios: males> females) could be due to the peculiar nature of the vestigial dewclaw of 2D and to the hormone patterns acting on this digit during development, but further research is required around this topic.
Topics: Animals; Bone Development; Bone and Bones; Cattle; Female; Forelimb; Male; Sex Characteristics; Toes
PubMed: 32248058
DOI: 10.1016/j.zool.2020.125777 -
Cognition Nov 2020Converting a multi-digit number to quantity requires processing not only the digits but also the number's decimal structure, thus raising several issues. First, are all...
Converting a multi-digit number to quantity requires processing not only the digits but also the number's decimal structure, thus raising several issues. First, are all the digits processed in parallel, or serially from left to right? Second, given that the same digit at different places can represent different quantities (e.g., "2" can mean 2, 20, etc.), how is each digit assigned to its correct decimal role? We presented participants with two-digit numbers and asked them to point at the corresponding locations on a number line, while we recorded their pointing trajectory. Crucially, on some trials, the decade and unit digits did not appear simultaneously. When the decade digit was delayed, the decade effect on finger movement was delayed by the same amount. However, a lag in presenting the unit digit delayed the unit effect by 35 ms less than the lag duration, a pattern reminiscent of the psychological refractory period, indicating an idle time window of 35 ms in the units processing pathway. When a lag transiently caused a display of just one digit on screen, the unit effect increased and the decade effect decreased, suggesting errors in binding digits to decimal roles. We propose that a serial bottleneck is imposed by the creation of a syntactic frame for the multidigit number, a process launched by the leftmost digit. All other stages, including the binding of digits to decimal roles, quantification, and merging them into a whole-number quantity, appear to operate in parallel across digits, suggesting a remarkable degree of parallelism in expert readers.
Topics: Fingers; Language; Movement; Refractory Period, Psychological; Time Perception
PubMed: 32645520
DOI: 10.1016/j.cognition.2020.104387 -
Developmental Cell Sep 2022Hedgehog signaling has traditionally been considered to be a morphogen for digits. In this issue of Developmental Cell, Zhu et al. show that a brief exposure to Sonic...
Hedgehog signaling has traditionally been considered to be a morphogen for digits. In this issue of Developmental Cell, Zhu et al. show that a brief exposure to Sonic Hedgehog is sufficient for digit specification, and this finding suggests that it is not acting as a direct morphogen but rather as an initiator of this process.
Topics: Body Patterning; Dust; Gene Expression Regulation, Developmental; Hedgehog Proteins; Limb Buds
PubMed: 36099905
DOI: 10.1016/j.devcel.2022.08.007 -
Cognition May 2020Such is the consistency by which performance on measures of short-term memory (STM) increase with age that developmental increases in STM capacity are largely accepted...
Such is the consistency by which performance on measures of short-term memory (STM) increase with age that developmental increases in STM capacity are largely accepted as fact. However, our analysis of a robust but almost ignored finding - that span for digit sequences (the traditional measure of STM) increases at a far greater rate than span for other verbal material - fundamentally undermines the assumption that increased performance in STM tasks is underpinned by developmental increases in capacity. We show that this digit superiority with age effect is explained by the relatively greater linguistic exposure to random sequences of digits versus other stimuli such as words. A simple associative learning process that learns incrementally from exposure to language accounts for the effect, without any need to invoke an STM mechanism, much less one that increases in capacity with age. By extension, using corpus data directed at 2-3 year old children, 4-6 year old children, and adults, we show that age-related performance increases with other types of verbal material are equally driven by the same basic associative learning process operating on the expanding exposure to language experienced by the child. Our results question the idea that tests such as digit span are measuring a dedicated system for the temporary maintenance and manipulation of verbal material, and as such have implications for our understanding of those aspects of typical and atypical development that are usually accounted for with respect to the operation of such a system.
Topics: Adult; Child; Child, Preschool; Humans; Language; Learning; Memory, Short-Term
PubMed: 32004933
DOI: 10.1016/j.cognition.2020.104200 -
Cortex; a Journal Devoted To the Study... Jan 2021The visual analysis of letter strings and digit strings is done by two separate cognitive processes. Recent studies have hypothesized that these processes are not only...
The visual analysis of letter strings and digit strings is done by two separate cognitive processes. Recent studies have hypothesized that these processes are not only separate but also qualitatively different, in that they may encode information specific to numbers or to words. To examine this hypothesis and to shed further light on the visual analysis of numbers, we asked adults to read aloud multi-digit strings presented to them for brief durations. Their performance was better in digits on the number's left side than in digits farther to the right, with better performance in the two outer digits than their neighbors. This indicates the digits were processed serially, from left to right. Visual similarity of digits increased the likelihood of errors, and when a digit migrated to an incorrect position, it was most often to an adjacent location. Interestingly, the positions of 0 and 1 were encoded better than the positions of 2-9, and 2-9 were identified better when they were next to 0 or 1. To accommodate these findings, we propose a detailed model for the visual analysis of digit strings. The model assumes imperfect digit detectors in which a digit's visual information leaks to adjacent locations, and a compensation mechanism that inhibits this leakage. Crucially, the compensating inhibition is stronger for 0 and 1 than for the digits 2-9, presumably because of the importance of 0 and 1 in the number system. This sensitivity to 0 and 1 makes the visual analyzer specifically adapted to numbers, not words, and may be one of the brain's reasons to implement the visual analysis of numbers and words in two separate cognitive processes.
Topics: Adaptation, Physiological; Adult; Humans; Inhibition, Psychological; Pattern Recognition, Visual; Probability; Reading
PubMed: 33279810
DOI: 10.1016/j.cortex.2020.10.012 -
Journal of Ultrasound in Medicine :... Dec 2019Trigger finger is a common pathologic condition of the digital pulleys and flexor tendons in the hand. The key clinical finding is a transient blockage of the digit when... (Review)
Review
Trigger finger is a common pathologic condition of the digital pulleys and flexor tendons in the hand. The key clinical finding is a transient blockage of the digit when it is flexed with subsequent painful snapping when it is extended. Imaging is a helpful guide for establishing the severity of the disease, identifying the underlying cause, and deciding the appropriate management. This narrative review aims to recall the anatomic and pathologic bases and describe the ultrasound features of trigger finger, also including common ultrasound findings and complications after therapy. Ultrasound enables an accurate static and dynamic evaluation of trigger finger as well as a comparison with the adjacent normal digits and thus should be considered the radiologic modality of first choice for its diagnosis.
Topics: Humans; Trigger Finger Disorder; Ultrasonography
PubMed: 31106876
DOI: 10.1002/jum.15025 -
Journal of the American Veterinary... Nov 2021To describe clinical findings, treatments, and outcomes for cattle with complete traumatic exungulation.
OBJECTIVE
To describe clinical findings, treatments, and outcomes for cattle with complete traumatic exungulation.
ANIMALS
10 bovines.
PROCEDURES
Record databases of 2 teaching hospitals were searched to identify cattle treated for traumatic exungulation between January 1993 and December 2018. Information about signalment, clinical signs and findings, treatment, and outcome was extracted from the records or obtained by telephone communication with the owner.
RESULTS
Records for 5 bulls, 4 heifers, and 1 cow with a median age of 2 years (range, 1 day to 10 years) and weight of 379.1 kg (range, 30 to 909.1 kg) were reviewed. Duration of clinical signs ranged from ≤ 24 hours to 3.5 days. Five of 7 animals had a lameness score > 3/5. Complete exungulation occurred in 6 medial digits (3 hind limbs and 3 forelimbs) and 5 lateral digits (1 hind limb and 4 forelimbs); 1 calf had complete exungulation of both digits of a forelimb. Treatments included bandaging (n = 9), antimicrobials (9), anti-inflammatories (8), hoof block application to the adjacent digit (7), regional anesthesia (6), cast application (4), curettage of the third phalanx (3), regional antimicrobial perfusion (1), and local application of antimicrobial-impregnated beads (1). All 7 cattle with long-term (≥ 9 months) information available returned to their intended function; 6 had no residual lameness, and 3 required regular corrective trimming of the affected digit.
CONCLUSIONS AND CLINICAL RELEVANCE
Results suggested the prognosis for long-term survival and return to intended function is fair to good for cattle with complete exungulation.
Topics: Animals; Anti-Bacterial Agents; Cattle; Cattle Diseases; Female; Forelimb; Gait; Hindlimb; Hoof and Claw; Lameness, Animal; Male
PubMed: 34757941
DOI: 10.2460/javma.21.06.0300