Biomedical subjects

Carsten Niemitz

Publications and source records attributed to Carsten Niemitz.

7 recordsLinked to original sources

PubMed2006

Recurrence plot analyses suggest a novel reference system involved in newborn spontaneous movements.

The movements of newborns have been thoroughly studied in terms of reflexes, muscle synergies, leg coordination, and target-directed arm/hand movements. Since these approaches have concentrated mainly on separate accomplishments, there has remained a clear need for more integrated investigations. Here, we report an inquiry in which we explicitly concentrated on taking such a perspective and, additionally, were guided by the methodological concept of home base behavior, which Ilan Golani developed for studies of exploratory behavior in animals. Methods from nonlinear dynamics, such as symbolic dynamics and recurrence plot analyses of kinematic data received from audiovisual newborn recordings, yielded new insights into the spatial and temporal organization of limb movements. In the framework of home base behavior, our approach uncovered a novel reference system of spontaneous newborn movements.

Biomechanical Phenomena↗

PubMed2004

Female sexual behavior, but not sex skin swelling, reliably indicates the timing of the fertile phase in wild long-tailed macaques (Macaca fascicularis).

The extent to which catharrine primate males are able to discern the fertile phase during the female ovarian cycle under natural conditions is still debated. In a recent study, we showed that wild male long-tailed macaques are able to detect the fertile phase, but the cues males used to assess female reproductive status remained unclear. In the present study, we tested female sex skin swelling and specific female behaviors for their reliability in signaling the fertile phase, as determined by measurement of fecal estrogens (E) and progestogens (P) during nine ovulatory cycles in seven free-ranging females. We found that changes in sex skin swellings showed a significant positive correlation to the E/P ratio, but swelling size did not significantly differ between cycle phases. In contrast, the frequency of two of the tested female behaviors, namely initiation of sexual interactions and reaching back for the male during copulation, was not only correlated with female reproductive hormones, but was significantly elevated during the fertile phase compared to nonfertile phases of the cycle. We thus conclude that female sex skin swelling does not reliably indicate the timing of the fertile phase in long-tailed macaques, whereas certain female behaviors do. Since cycles differed considerably in the number of males with which females had sexual interactions as well as in the number of sexual interactions with dominant males, the signaling character of these specific female behaviors appears to be robust against inconsistencies in these social variables. Female behavior might therefore play an important role in the recognition of the fertile phase by male macaques under natural conditions.

Anal Canal↗

PubMed2003

"Right-trunkers" and "left-trunkers": side preferences of trunk movements in wild Asian elephants (Elephas maximus).

In this article, the side preferences of feeding-related trunk movements of free-ranging Asian elephants (Elephas maximus) were investigated for the first time. It is hypothesized that a functional asymmetry of the trunk is necessary to perform skillful feeding movements more efficiently. This might be connected with a corresponding hemispheric specialization. Video recordings of 41 wild elephants provided frequencies and durations of the following trunk-movement categories: object contact, retrieval, and reaching. In each category, individual side preferences were found. The strength of side preferences varied between the trunk-movement categories and the sexes. Mean durations of retrieval and reaching correlated negatively with the strength of side biases. Comparing the side preferences in the unpaired trunk with analogous phenomena in other unpaired grasping organs and in primate handedness. the authors discuss possible explanations for the evolution of asymmetries in unpaired grasping organs.

Animals↗

PubMed2003

Age structure and selected pathological aspects of a series of skeletons of late medieval Bernau (Brandenburg, Germany).

The age distribution of an excavation site from the late Middle Ages (beginning of the 13th century until 1598) in Bernau (Brandenburg, Germany) that contained 252 skeletons shows a mortality maximum at the age classes infants I and mature. The lowest mortality was calculated for the adult age class. 51.6% of the individuals died before the age of 20 years. The mortality rate of young women was higher than that of young men. The life expectancy of the total population was 25 years. Altogether, 87 adult skeletons were examined for degenerative joint diseases. Many of the examined joints showed indications of beginning osteoarthritis; the intensity of the disease was low or medium severe. The highest values were found for the hip joint, followed by the elbow and the knee. For all joints examined, women were less often and to a lesser extent affected than men, which was noticeable best in the upper extremity. Harris lines were found in 75% of the children, 4.7 per average individual. No such lines were found by the age of one year, the peak value of the frequency being recorded at the age between 2 and 3 years. This can be correlated to the weaning period. The comparison to a rural population yielded a higher load with Harris lines in the small village, which, however, was not correlated to a higher mortality. Altogether, the population of Bernau is characterised by good living conditions and a considerable chance of survival for the children, as well as by a labour system, dominated by crafts and farming.

Adolescent↗

PubMed2003

Results of an explorative empirical study on human mating in Germany: handsome men, not high-status men, succeed in courtship.

Recent research on human mating depicts men as searching for physical attractiveness (PA) and women as searching for status. To identify the mechanisms which lead to universal, biologically interpretable structures in social processes, we focused on the proximate causes for inter- and intrasexual differences in human mating preferences, attraction, and tactics. We collected data on 180 young singles (mean age 26.9 years) without a steady relationship. A questionnaire and a video sequence (20-30 seconds) of each subject was taken. Next, each video sequence was rated by approximately 20 individuals of the opposite sex, who also participated in this study. Surprisingly, the answers given by male and female subjects regarding sociosexual behaviour and mating preferences are predominantly congruent. Sex differences among preferences for good looking and high-status partners were small or even insignificant. Lower educated subjects had considerably higher status preferences than higher educated individuals. In both sexes, PA was much more preferred in a potential partner than status. For both sexes, physical appearance was decisive for the subject's dating attractiveness. Male, but not female dating attractiveness also correlates with a kind and charismatic appearance. Furthermore, there was a positive linear relationship between men's PA and their number of sexual partners within the last year. Men with more than four sexual partners were all above-average in PA, while the most attractive women had a medium number of sexual partners. However, in this respect, status had no influence. The results show that sex differences in mating are more complex than hitherto assumed.

Adult↗

PubMed2002

Kinematics and ontogeny of locomotion in monkeys and human babies.

Early ontogenetic stages are often assumed to reflect or to be similar to past phylogenetic stages within the evolution of man. Therefore, as a first step, the quadrupedal crawling locomotion of human children was analysed and compared to the quadrupedal walk of Macaca fascicularis. The movements of the human child were not only more irregular, they differed from the walk of the monkey mainly through extraordinarily short swing phases, and also through strong scoliotic movements of the spine. There is a compulsory synchronisation in the hip and knee joint movements of the human crawling baby. We conclude that human crawling may be a behavioural recapitulation of a quadrupedal evolutionary stage. However, with reference to kinematics, man is not only characterised by his unique, habitually bipedal, upright gait but also by a second, equally unique locomotion, namely crawling, which he assumes for a short phase during his first year of life.--The walking movements of the limbs in toddling infants were mainly characterised by i) rather stiff, abducted arms, which were moved mostly by spine torsions (similar to those of bipedally walking Gorilla) and not as a suspensory pendulum. However, they rather work as levers for the elastic torsion pendulum of the spine. ii) They are also characterised by frequently lacking the minor knee flexion, which occurs at about the heel strike within each stride of the adult human. Besides many other details of the results, foot movements differed from adult ones mainly in that the whole plantar surface was placed flat on the ground within a few milliseconds.

Aging↗

PubMed2002

A theory on the evolution of the habitual orthograde human bipedalism--the "Amphibische Generalistentheorie".

The theory is formulated that ubiquitous scarcity of energy is one of the main motors of evolution. It is concluded that our primate ancestors never came down from the trees, but rather they have always been (semi-)terrestrial. This habit is probably an old symplesiomorph trait, older than primates themselves. Terrestrial habits in primates correlate to body weight in small systematic groups (e.g., large genera, families) but are, overall, completely independent from individual body mass. An omnivorous, semiterrestrial quadrupedal locomotor generalist seems to be the most probable morpho- and eco-type for our ancestor at the threshold of a hominoid stage of our evolution. The theory presented here suggests that our hominoid ancestor lived in gallery forests and changed strata in order also to inhabit the savannah habitat as well as the shallow water of the rivers or coasts. Foraging in a wading manner was extremely favourable for an effective and, especially, seasonally independent, animal protein supply. Anatomical adaptations to orthogradism and proportions of the extremities are discussed in relation to the necessary and frequent change of habitat strata. Ultimately, human bipedalism is seen here to be derived as a consequence of the centre of body mass, which is, in primates, near the hind extremities. By contrast to other mammals entering the water, wading primates sink back on their hind limbs. Selective forces for habitat use, limb proportions and wading habits are discussed, as well as the phylogenetic origin of human affinity to water and shores in all peoples through all times, from australopithecine times through the Paleolithic until today.

Animals↗