John D Polk
Datos Biográficos
| ID | 3527832 |
|---|---|
| NOMBRE | John D Polk |
| NOMBRES | John D |
| APELLIDO | Polk |
| FIRMA | POLK J D |
| AFILIACIONES | University of Illinois Urbana-Champaign |
| ORCID | 0000-0002-8977-6635 |
| VERIFICADO | Sí |
| TOTAL DE OBRAS | 16 |
| TOTAL DE CITAS | 188 |
| TOTAL COMO AUTOR | 16 |
| TOTAL COMO EDITOR | 0 |
| PRIMER AÑO DE PUBLICACIÓN | 2000 |
| AÑO MÁS RECIENTE DE PUBLICACIÓN | 2021 |
| ÍNDICE H | 5 |
Scaling of linear anthropometric dimensions in living humans
OBJECTIVES: Some previous studies suggest that humans do not conform to geometric similarity (isometry) in anthropometric dimensions of the upper and lower limbs. Researchers often rely on a single statistical approach to the study of scaling patterns, and it is unclear whether these methods produce similar results and are equally robust. This study used one bivariate and one multivariate method to examine how linear anthropometric dimensions sca…
BDNF, endurance activity, and mechanisms underlying the evolution of hominin brains
OBJECTIVES: As a complex, polygenic trait, brain size has likely been influenced by a range of direct and indirect selection pressures for both cognitive and non-cognitive functions and capabilities. It has been hypothesized that hominin brain expansion was, in part, a correlated response to selection acting on aerobic capacity (Raichlen & Polk, 2013). According to this hypothesis, selection for aerobic capacity increased the activity of various …
Humans Crawl
Ontogenetic scaling of fore limb and hind limb joint posture and limb bone cross‐sectional geometry in vervets and baboons
OBJECTIVES: Previous studies suggest that the postures habitually adopted by an animal influence the mechanical loading of its long bones. Relatively extended limb postures in larger animals should preferentially reduce anteroposterior (A-P) relative to mediolateral (M-L) bending of the limb bones and therefore decrease A-P/M-L rigidity. We test this hypothesis by examining growth-related changes in limb bone structure in two primate taxa that di…
The primate vaginal microbiome
The primate body hosts trillions of microbes. Interactions between primate hosts and these microbes profoundly affect primate physiology, reproduction, health, survival, and ultimately, evolution. It is increasingly clear that primate health cannot be understood fully without knowledge of host‐microbial interactions. Our goals here are to review what is known about microbiomes of the female reproductive tract and to explore several factors that i…
Divergent Patterns of Integration and Reduced Constraint in the Human Hip and the Origins of Bipedalism
When compared to other hominids--great apes including humans--the human pelvis reveals a fundamental reorganization of bony morphology comprised of multiple trait-level changes, many of which are associated with bipedal locomotion. Establishing how patterns of integration--correlations and covariances among traits--within the pelvis have evolved in concert with morphology is essential to explaining this evolutionary transition because integration…
Subchondral Bone Apparent Density and Locomotor Behavior in Extant Primates and Subfossil Lemurs Hadropithecus and Pachylemur
Distal Forelimb Kinematics in Erythrocebus patas and Papio anubis During Walking and Galloping
Body size and joint posture in primates
Body mass has been shown in experimental and comparative morphological studies to have a significant effect on joint posture in major limb joints. The generalizability of experimental studies is limited by their use of small sample sizes and limited size ranges. In contrast, while comparative morphological studies often have increased sample sizes, the connection between joint posture and morphological variables is often indirect. The current stu…
Trabecular bone in the bird knee responds with high sensitivity to changes in load orientation
Wolff's law of trajectorial orientation proposes that trabecular struts align with the orientation of dominant compressive loads within a joint. Although widely considered in skeletal biology, Wolff's law has never been experimentally tested while controlling for ontogenetic stage, activity level,and species differences, all factors that may affect trabecular bone growth. Here we report an experimental test of Wolff's law using a within-species d…
Forelimb and hindlimb forces in walking and galloping primates
One trait that distinguishes the walking gaits of most primates from those of most mammalian nonprimates is the distribution of weight between the forelimbs and hindlimbs. Nonprimate mammals generally experience higher vertical peak substrate reaction forces on the forelimb than on the hindlimb. Primates, in contrast, generally experience higher vertical peak substrate reaction forces on the hindlimb than on the forelimb. It is currently unclear …
Sampling frequencies and measurement error for linear and temporal gait parameters in primate locomotion
Predicting long bone loading from cross‐sectional geometry
Long bone loading histories are commonly evaluated using a beam model by calculating cross‐sectional second moments of areas (SMAs). Without in vivo strain data, SMA analyses commonly make two explicit or implicit assumptions. First, while it has long been known that axial compression superimposed on bending shifts neutral axes away from cross‐sectional area centroids, most analyses assume that cross‐sectional properties calculated through the ar…
Influences of limb proportions and body size on locomotor kinematics in terrestrial primates and fossil hominins
Abstracts of AAPA poster and podium presentations
The human face differs from most other primates in that it lacks a rostrum and is oriented primarily in the coronal plane. These differences may influence biomechanical resistance to torsional, shearing, and bending forces generated during mastication that are known to affect the growth of the maxillary and mandibular arches. We tested the effects of facial retraction on facial strain patterns using in vivo strain data collected from rock hyraxes…
A comparison of primate, carnivoran and rodent limb bone cross-sectional properties
Predicting long bone loading from cross‐sectional geometry
Long bone loading histories are commonly evaluated using a beam model by calculating cross‐sectional second moments of areas (SMAs). Without in vivo strain data, SMA analyses commonly make two explicit or implicit assumptions. First, while it has long been known that axial compression superimposed on bending shifts neutral axes away from cross‐sectional area centroids, most analyses assume that cross‐sectional properties calculated through the ar…
A comparison of primate, carnivoran and rodent limb bone cross-sectional properties
Influences of limb proportions and body size on locomotor kinematics in terrestrial primates and fossil hominins
Forelimb and hindlimb forces in walking and galloping primates
One trait that distinguishes the walking gaits of most primates from those of most mammalian nonprimates is the distribution of weight between the forelimbs and hindlimbs. Nonprimate mammals generally experience higher vertical peak substrate reaction forces on the forelimb than on the hindlimb. Primates, in contrast, generally experience higher vertical peak substrate reaction forces on the hindlimb than on the forelimb. It is currently unclear …
Body size and joint posture in primates
Body mass has been shown in experimental and comparative morphological studies to have a significant effect on joint posture in major limb joints. The generalizability of experimental studies is limited by their use of small sample sizes and limited size ranges. In contrast, while comparative morphological studies often have increased sample sizes, the connection between joint posture and morphological variables is often indirect. The current stu…
Distal Forelimb Kinematics in Erythrocebus patas and Papio anubis During Walking and Galloping
Sampling frequencies and measurement error for linear and temporal gait parameters in primate locomotion
Ontogenetic scaling of fore limb and hind limb joint posture and limb bone cross‐sectional geometry in vervets and baboons
OBJECTIVES: Previous studies suggest that the postures habitually adopted by an animal influence the mechanical loading of its long bones. Relatively extended limb postures in larger animals should preferentially reduce anteroposterior (A-P) relative to mediolateral (M-L) bending of the limb bones and therefore decrease A-P/M-L rigidity. We test this hypothesis by examining growth-related changes in limb bone structure in two primate taxa that di…
The primate vaginal microbiome
The primate body hosts trillions of microbes. Interactions between primate hosts and these microbes profoundly affect primate physiology, reproduction, health, survival, and ultimately, evolution. It is increasingly clear that primate health cannot be understood fully without knowledge of host‐microbial interactions. Our goals here are to review what is known about microbiomes of the female reproductive tract and to explore several factors that i…
Subchondral Bone Apparent Density and Locomotor Behavior in Extant Primates and Subfossil Lemurs Hadropithecus and Pachylemur
Abstracts of AAPA poster and podium presentations
The human face differs from most other primates in that it lacks a rostrum and is oriented primarily in the coronal plane. These differences may influence biomechanical resistance to torsional, shearing, and bending forces generated during mastication that are known to affect the growth of the maxillary and mandibular arches. We tested the effects of facial retraction on facial strain patterns using in vivo strain data collected from rock hyraxes…
A comparison of primate, carnivoran and rodent limb bone cross-sectional properties
Abstracts of AAPA poster and podium presentations
The human face differs from most other primates in that it lacks a rostrum and is oriented primarily in the coronal plane. These differences may influence biomechanical resistance to torsional, shearing, and bending forces generated during mastication that are known to affect the growth of the maxillary and mandibular arches. We tested the effects of facial retraction on facial strain patterns using in vivo strain data collected from rock hyraxes…
Predicting long bone loading from cross‐sectional geometry
Long bone loading histories are commonly evaluated using a beam model by calculating cross‐sectional second moments of areas (SMAs). Without in vivo strain data, SMA analyses commonly make two explicit or implicit assumptions. First, while it has long been known that axial compression superimposed on bending shifts neutral axes away from cross‐sectional area centroids, most analyses assume that cross‐sectional properties calculated through the ar…
Influences of limb proportions and body size on locomotor kinematics in terrestrial primates and fossil hominins
Sampling frequencies and measurement error for linear and temporal gait parameters in primate locomotion
Trabecular bone in the bird knee responds with high sensitivity to changes in load orientation
Wolff's law of trajectorial orientation proposes that trabecular struts align with the orientation of dominant compressive loads within a joint. Although widely considered in skeletal biology, Wolff's law has never been experimentally tested while controlling for ontogenetic stage, activity level,and species differences, all factors that may affect trabecular bone growth. Here we report an experimental test of Wolff's law using a within-species d…
Forelimb and hindlimb forces in walking and galloping primates
One trait that distinguishes the walking gaits of most primates from those of most mammalian nonprimates is the distribution of weight between the forelimbs and hindlimbs. Nonprimate mammals generally experience higher vertical peak substrate reaction forces on the forelimb than on the hindlimb. Primates, in contrast, generally experience higher vertical peak substrate reaction forces on the hindlimb than on the forelimb. It is currently unclear …
Body size and joint posture in primates
Body mass has been shown in experimental and comparative morphological studies to have a significant effect on joint posture in major limb joints. The generalizability of experimental studies is limited by their use of small sample sizes and limited size ranges. In contrast, while comparative morphological studies often have increased sample sizes, the connection between joint posture and morphological variables is often indirect. The current stu…
Subchondral Bone Apparent Density and Locomotor Behavior in Extant Primates and Subfossil Lemurs Hadropithecus and Pachylemur
Distal Forelimb Kinematics in Erythrocebus patas and Papio anubis During Walking and Galloping
Divergent Patterns of Integration and Reduced Constraint in the Human Hip and the Origins of Bipedalism
When compared to other hominids--great apes including humans--the human pelvis reveals a fundamental reorganization of bony morphology comprised of multiple trait-level changes, many of which are associated with bipedal locomotion. Establishing how patterns of integration--correlations and covariances among traits--within the pelvis have evolved in concert with morphology is essential to explaining this evolutionary transition because integration…
The primate vaginal microbiome
The primate body hosts trillions of microbes. Interactions between primate hosts and these microbes profoundly affect primate physiology, reproduction, health, survival, and ultimately, evolution. It is increasingly clear that primate health cannot be understood fully without knowledge of host‐microbial interactions. Our goals here are to review what is known about microbiomes of the female reproductive tract and to explore several factors that i…
Ontogenetic scaling of fore limb and hind limb joint posture and limb bone cross‐sectional geometry in vervets and baboons
OBJECTIVES: Previous studies suggest that the postures habitually adopted by an animal influence the mechanical loading of its long bones. Relatively extended limb postures in larger animals should preferentially reduce anteroposterior (A-P) relative to mediolateral (M-L) bending of the limb bones and therefore decrease A-P/M-L rigidity. We test this hypothesis by examining growth-related changes in limb bone structure in two primate taxa that di…
Humans Crawl
BDNF, endurance activity, and mechanisms underlying the evolution of hominin brains
OBJECTIVES: As a complex, polygenic trait, brain size has likely been influenced by a range of direct and indirect selection pressures for both cognitive and non-cognitive functions and capabilities. It has been hypothesized that hominin brain expansion was, in part, a correlated response to selection acting on aerobic capacity (Raichlen & Polk, 2013). According to this hypothesis, selection for aerobic capacity increased the activity of various …
Scaling of linear anthropometric dimensions in living humans
OBJECTIVES: Some previous studies suggest that humans do not conform to geometric similarity (isometry) in anthropometric dimensions of the upper and lower limbs. Researchers often rely on a single statistical approach to the study of scaling patterns, and it is unclear whether these methods produce similar results and are equally robust. This study used one bivariate and one multivariate method to examine how linear anthropometric dimensions sca…
Biology (13 obras) · Primate Behavior and Ecology (10 obras) · Anatomy (7 obras) · Anatomy (7 obras) · Mathematics (7 obras) · Primate (7 obras) · Medicine (6 obras) · Amphibian and Reptile Biology (5 obras) · Ecology (5 obras) · Ecology (4 obras)