Abstract：
:How do arm-swinging apes locomote effectively over a variety of speeds? One way to reduce the metabolic energy cost of locomotion is to transfer energy between reversible mechanical modes. In terrestrial animals, at least two transfer mechanisms have been identified: 1) a pendulum-like mechanism for walking, with exchange between gravitational potential energy and translational kinetic energy, and 2) a spring-like mechanism for running, where the elastic strain energy of stretched muscle and tendon is largely returned to reaccelerate the animal. At slower speeds, a brachiator will always have at least one limb in contact with the support, similar to the overlap of foot contact in bipedal walking. At faster speeds, brachiators exhibit an aerial phase, similar to that seen in bipedal running. Are there two distinct brachiation gaits even though the animal appears to simply swing beneath its overhead support? If so, are different exchange mechanisms employed? Our kinetic analysis of brachiation in a white-handed gibbon (Hylobates lar) indicates that brachiation is indeed comprised of two mechanically distinct gaits. At slower speeds in "continuous contact" brachiation, the gibbon utilizes a simple pendulum-like transfer of mechanical energy within each stride. At faster speeds in "ricochetal" brachiation, translational and rotational kinetic energy are exchanged in a novel "whip-like" transfer. We propose that brachiators utilize the transfer between translational and rotational kinetic energy to control the dynamics of their swing. This maneuver may allow muscle action at the shoulder to control the transfer and adjust the ballistic portion of the step to meet the requirements for the next hand contact.
journal_name
Am J Phys Anthropoljournal_title
American journal of physical anthropologyauthors
Bertram JE,Chang YHdoi
10.1002/ajpa.1088subject
Has Abstractpub_date
2001-08-01 00:00:00pages
319-26issue
4eissn
0002-9483issn
1096-8644journal_volume
115pub_type
杂志文章abstract：:This paper is one in a series which explores the possibility of using the non-destructive CT technique to identify patterns in tooth enamel distribution and structure of hominid molars from Plio-Pleistocene sites in South Africa, notably Swartkrans, Sterkfontein, and Kromdraai. Whereas previous investigators have emph...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.1330890202
更新日期：1992-10-01 00:00:00
abstract：:During the 1992 and 1993 field seasons, several new specimens of Branisella boliviana, the oldest fossil platyrrhine, were discovered in the late Oligocene deposits at Salla, northwestern Bolivia. The new materials are two maxillary fragments and seven mandibular fragments, including P3 and P2, neither of which have p...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/(SICI)1096-8644(199602)99:2<301::AID-AJPA7
更新日期：1996-02-01 00:00:00
abstract：:It is unclear whether earlier age at menarche is associated with higher body mass index (BMI) because they share a common genetic underpinning. We investigated the impact of single nucleotide polymorphisms (SNPs) influencing menarche timing on peripubertal BMI. For 556 Fels Longitudinal Study children (277 boys/279 gi...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.22121
更新日期：2013-01-01 00:00:00
abstract：:Pair-bonding in the genus Papio seems to be the result of fusion of troops as well as fission. When troop segments regularly split and join again, males who permanently maintain exclusive access to a few females may have an advantage over males who compete for all females who are in estrus. When two or more troops reg...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.1330600104
更新日期：1983-01-01 00:00:00
abstract：:Large body size has been traditionally seen as the primary dietary adaptation of gorillas, facilitating their consumption of fibrous foods (Schaller ¿1963 The Mountain Gorilla; Watts ¿1990 Int. J. Primatol. 11:21-45). Nevertheless, recent research has emphasized frugivory among western lowland gorillas, as well as the...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/(SICI)1096-8644(2000)112:2<171::AID-AJPA4>
更新日期：2000-06-01 00:00:00
abstract：:Excavations at hearth levels at the Molare Shelter in 1985 yielded the mandible of a 3-4-year-old child. The associated lithic artifacts recovered with it are Mousterian. Its features, although quite archaic, are within the known range of variation of Neandertals. Four deciduous molars are still preserved in the mandi...
journal_title：American journal of physical anthropology
pub_type： 历史文章,杂志文章
doi：10.1002/ajpa.1330790404
更新日期：1989-08-01 00:00:00
abstract：:The objective of this study is to present the characteristics of a collection of identified infants and young children housed in the Laboratory of Anthropology of the University of Granada, Spain. The sample, which is still being enlarged, is currently composed of 230 complete skeletons aged from 5 months of gestation...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.22165
更新日期：2012-12-01 00:00:00
abstract：:This study analyzes the distribution of ten protein genetic polymorphisms in eighteen populations from the most densely inhabited areas of Cameroon. The languages spoken belong to three different linguistic families [Afro-Asiatic (AA), Nilo-Saharan (NS) and Niger-Kordofanian (NK)]. The analysis of variation of allele ...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/(SICI)1096-8644(199910)110:2<143::AID-AJPA
更新日期：1999-10-01 00:00:00
abstract：:Sibling correlations for size attained in height, weight, sitting height, estimated leg length, the triceps skinfold, arm circumference, and estimated midarm muscle circumference were compared in 6- through 13-year-old schoolchildren grouped by household socioeconomic status. The children were residents of a Zapotec-s...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.1330710110
更新日期：1986-09-01 00:00:00
abstract：:Height and weight were compared across five birth decades (1850-1899) among 1,121 Harvard athletes who were lettermen in various sports. There were considerable differences in the magnitude of the secular trend among the sport categories (crew, baseball, football, track, ice hockey, and two or more sports). Comparing ...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.1330420318
更新日期：1975-05-01 00:00:00
abstract：:A new partial skeleton of Proconsul nyanzae from Mfangano Island, Kenya (KNM-MW 13142) includes five lumbar vertebrae, a partial sacrum, and nearly complete hipbone. Until recently, little was known of the axial and pelvic skeletons of Proconsul, or any early Miocene hominoid. Because torso morphology directly reflect...
journal_title：American journal of physical anthropology
pub_type： 历史文章,杂志文章
doi：10.1002/ajpa.1330920306
更新日期：1993-11-01 00:00:00
abstract：:The adventus Saxonum is a crucial event in English protohistory. Scholars from a range of disciplines dispute the scale and demographic profile of the purported colonizing population. The 5th-7th century burial ground at West Heslerton, North Yorkshire, is one of the few Anglian cemeteries where an associated settleme...
journal_title：American journal of physical anthropology
pub_type： 历史文章,杂志文章
doi：10.1002/ajpa.20111
更新日期：2005-02-01 00:00:00
abstract：:Various workers, including T. D. Stewart, claim that the aboriginal Americas were relatively disease-free because of the bering Strait cold-screen, eliminating many pathogens, and the paucity of zoonotic infections because of few domestic animals. Evidence of varying validity suggests that precontact Americns had thei...
journal_title：American journal of physical anthropology
pub_type： 历史文章,杂志文章
doi：10.1002/ajpa.1330450333
更新日期：1976-11-01 00:00:00
abstract：:As a part of a research project on molecular variation in Central Africa, we have analyzed 10 microsatellites (CD4, CSFO, D3S1358, D18S51, D21S11, F13A1, FES, TH01, TPOX, and VWA) in the Bamileke and Ewondo from Cameroon and the Sanga and Mbenzele Pygmies from the Central African Republic (a total of 390 chromosomes)....
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/1096-8644(200007)112:3<319::AID-AJPA4>3.0.
更新日期：2000-07-01 00:00:00
abstract：:The robustness index (RI) is determined by multiplying dental mesiodistal and buccolingual diameters, and is used to estimate occlusal area. However, because teeth are not rectangular its calculation consistently causes overestimations. Moreover, teeth, in particular molars, are not identically shaped so overestimatio...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.21511
更新日期：2011-06-01 00:00:00
abstract：:Histomorphometric analysis of femoral and tibial diaphyseal fragments from seven Late Archaic and three Early Modern humans are compared with those of the Pecos, a pre-Columbian Native American population. The ten samples, from Broken Hill (EM-793), Shanidar 2, 3, 4, 5, and 6, Tabun 1, and Skhul 3, 6, and 7, provide a...
journal_title：American journal of physical anthropology
pub_type： 历史文章,杂志文章
doi：10.1002/(SICI)1096-8644(199604)99:4<585::AID-AJPA5
更新日期：1996-04-01 00:00:00
abstract：:Bilateral tooth measurements in twins are partitioned into three orthogonal contrasts, each associated with one degree of freedom, to estimate three parameters: discordance, asymmetry, and mirror imagery. The probability levels of the within-pair variance ratios were used to test for significance of these estimates. T...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.1330440303
更新日期：1976-05-01 00:00:00
abstract：:The Miles system of ageing, based upon analysis of the rate of molar wear, was evaluated using the available dental sample from Tepe Hissar, Iran. The independently estimated ages for the mandibles and maxillae of the same individuals were found to be highly correlated (r = 0.87, p less than 0.001). Ages of a subsampl...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.1330490216
更新日期：1978-08-01 00:00:00
abstract：:Callitrichids use their tongue in various social, ecological, and hygienic contexts. Using a noninvasive measuring device, we obtained data on the operational tongue length (OTL) in seven species from the family Callitrichidae. OTL (defined as the maximum tongue extension into the device) varied significantly between ...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.21038
更新日期：2009-07-01 00:00:00
abstract：OBJECTIVES:The Early Neolithic involved an important social and economic shift that can be tested not only with the material culture, but also through biomolecular approaches. The Iberian Peninsula presents few Early Neolithic sites where fauna and humans can be analyzed together from an isotopic perspective. Here we p...
journal_title：American journal of physical anthropology
pub_type： 历史文章,杂志文章
doi：10.1002/ajpa.23622
更新日期：2018-10-01 00:00:00
abstract：:Pliopithecid remains from the Spanish locality of Torrent de Febulines (Late Vallesian, MN 10), consisting of right and left mandibular fragments with partial tooth rows and an isolated P(3) probably belonging to the same individual, are described and assigned to Egarapithecus narcisoi gen. et sp. nov. (Pliopithecidae...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.1043
更新日期：2001-04-01 00:00:00
abstract：:New data were obtained on mitochondrial DNA (mtDNA) from Guahibo from Venezuela, a group so far not studied using molecular data. A population sample (n = 59) was analyzed for mtDNA variation in two control-region hypervariable segments (HV1 and HV2) by sequencing. The presence or absence of a 9-bp polymorphism in the...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.20070
更新日期：2005-07-01 00:00:00
abstract：:This study uses data resampling to test the null hypothesis that the degree of variation in the cranial capacity of the Dmanisi hominid sample is within the range variation of a single species. The statistical significance of the variation in the Dmanisi sample is examined using simulated distributions based on compar...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.20105
更新日期：2005-07-01 00:00:00
abstract：OBJECTIVES:Vertical clinging and climbing have been integral to hypotheses about primate origins, yet little is known about how an animal with nails instead of claws resists gravity while on large, vertical, and cylindrical substrates. Here we test models of how force is applied to maintain posture, predicting (1) the ...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.22803
更新日期：2015-11-01 00:00:00
abstract：:The transferrin phenotypes of 256 rhesus monkeys and their parents were identified by polyacrylamide gel electrophoresis. The segregation ratio for phenotypes involving only alleles of high electrophoretic mobility was statistically significantly higher than expected and suggests that selection favors these more negat...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.1330580403
更新日期：1982-08-01 00:00:00
abstract：:Bone mass, as assessed by measurements of total subperiosteal diameter and medullary width of the second metacarpal bone on hand-wrist radiographs, was evaluated for 31 Guamanian patients (15 males, 16 females) with amyotrophic lateral sclerosis (ALS), 67 patients (39 males, 28 females) with parkinsonism-dementia (PD)...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.1330800112
更新日期：1989-09-01 00:00:00
abstract：OBJECTIVES:The diet of tufted capuchins (Sapajus) is characterized by annual or seasonal incorporation of mechanically protected foods. Reliance on these foods raises questions about the dietary strategies of young individuals that lack strength and experience to access these resources. Previous research has demonstrat...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.22865
更新日期：2016-02-01 00:00:00
abstract：:This study was designed to investigate the relationship between traditional skeletal cephalometric measurement and Fourier analysis of the lateral soft-tissue profile. A random sample of 121 untreated subjects of European descent, with wide ranges of malocclusions and underlying facial patterns, was selected in the Or...
journal_title：American journal of physical anthropology
pub_type： 临床试验,杂志文章,随机对照试验
doi：10.1002/ajpa.10173
更新日期：2003-06-01 00:00:00
abstract：:The Yakuts are a Turkic-speaking population from northeastern Siberia who are believed to have originated from ancient Turkic populations in South Siberia, based on archaeological and ethnohistorical evidence. In order to better understand Yakut origins, we modeled 25 demographic scenarios and tested by coalescent sim...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.21003
更新日期：2009-08-01 00:00:00
abstract：:Previous works on the inheritance of dental traits have traditionally followed Fisher's model for family data under the assumption that phenotypic similarity between relatives is due solely to genetic factors. This study uses recent causal models that incorporate the contribution of nonrandom environmental sources of ...
journal_title：American journal of physical anthropology
pub_type： 杂志文章
doi：10.1002/ajpa.1330610302
更新日期：1983-07-01 00:00:00
