Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Slaves”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed2006

Analysis of a master-slave architecture for distributed evolutionary computations.

This paper introduces a new mathematical model of the master-slave architecture for distributed evolutionary computations (EC). This model is validated using a concrete implementation based on the Distributed BEAGLE C++ framework. Results show that contrary to (current) popular belief, master-slave architectures are able to scale well over local area networks of workstations using off-the-shelf networking equipment. The main properties of the master-slave are also compared with those of the more mainstream island-model.

Artificial Intelligence↗
PubMedDate not supplied

Development of anthropomorphic multi-D.O.F. master-slave arm for mutual telexistence.

We developed a robotic arm for a master-slave system to support "mutual telexistence," which realizes remote dexterous manipulation tasks and close physical communication with other people using gestures. In this paper, we describe the specifications of the experimental setup of the master-slave arm to demonstrate the feasibility of the mutual telexistence concept. We developed the master arm of a telexistence robot for interpersonal communication. The last degree of the 7-degree-of-freedom slave arm is resolved by placing a small orientation sensor on the operators arm. This master arm is made light and impedance control is applied in order to grant the operator as much freedom of movement as possible. For this development stage, we compared three control methods and confirmed that the impedance control method is the most appropriate to this system.

Arm↗
PubMed1971

Chemical communication and "propaganda" in slave-maker ants.

Slave-maker ants of the Formica sanguinea group direct their raids by means of odor trails. Artificial trails made from whole-body extracts and extracts of Dufour's glands and hindguts can be used to guide columns of workers to selected target colonies and to initiate raids. In workers of F. pergandei and F. subintegra, members of the F. sanguinea group, the Dufour's glands are hypertrophied and contain large quantities of three acetates (decyl, dodecyl, and tetradecyl), which are discharged at defending workers during the slave raids. The acetates produce very efficient, long-lasting alarm signals that attract the slave-makers but disperse the defenders; in effect, therefore, they are "propaganda substances."

Acetates↗
PubMed2002

The peopling of São Tomé (Gulf of Guinea): origins of slave settlers and admixture with the Portuguese.

The geographic origins of African slave settlers and the Portuguese genetic contribution to the population of São Tomé (Gulf of Guinea) were assessed through the analysis of beta-globin haplotypes in 44 chromosomes bearing the betaS allele and through the study of the genetic variation in eight autosomal markers (APOA1, AT3, FY, LPL, OCA2, RB1, Sb19.3, and GC) informative for admixture in a sample of 224 individuals. The observed betaS haplotype distribution (36.4% Bantu, 52.3% Benin, 4.5% Cameroon, 4.5% Senegal, and 2.3% atypical) is in accordance with the historical information on the major geographic sources of slave settlers of São Tomé, although it captures a more important contribution of Central-West Africa regions than previously anticipated. European admixture, estimated to be 10.7 +/- 0.9%, has created a considerable level of genetic structure, as indicated by the finding of significant linkage disequilibrium between 33% of unlinked marker loci pairs. Recent admixture was found to have an important contribution to these values, since removal of individuals with Portuguese or Cape Verdian parents or grandparents from the sample dropped the miscegenation level to 6.5 +/- 0.8% and reduced significant linkage disequilibrium to 11% of unlinked marker pairs. Taken together, these results indicate that the peopling of São Tomé might have provided one of the first examples of the combination of diverse African contributions and European admixture that emerged from the overseas population relocations promoted by the Atlantic slave trade.

Africa↗
PubMed2006

MtDNA haplogroup analysis of black Brazilian and sub-Saharan populations: implications for the Atlantic slave trade.

Seventy individuals from two African and four black Brazilian populations were studied for the first hypervariable segment of mtDNA. To delineate a more complete phylogeographic scenario of the African mtDNA haplogroups in Brazil and to provide additional information on the nature of the Atlantic slave trade, we analyzed our data together with previously published data. The results indicate different sources of African slaves for the four major Brazilian regions. In addition, the data revealed patterns that differ from those expected on the basis of historical registers, thus suggesting the role of ethnic sex differences in the slave trade.

Africa South of the Sahara↗
PubMed2000

[Surgery using master-slave manipulators and telementoring].

Master-slave manipulators enhance surgeons' dexterity and improve the precision of surgical techniques by filtering out surgeons' tremors and scaling the movements of surgical instruments. Among clinically available master-slave manipulators, the epoch-making system called "da Vinci" developed by Intuitive Surgical Inc. (Mountain View, CA, USA), equipped with 2 articulated joints at the tip of the surgical instruments allowing 7 degrees of freedom, mimics the movements of surgeons' wrists and fingers in the abdominal or thoracic cavity. Today advanced telecommunications technology provides us excellent motion images using only 3-ISDN telephone lines. Experienced surgeons at primary surgical sites have been able to perform complex procedures successfully by consulting specialists at remote sites. Because telecommunications costs have become lower each year, telementoring will be come a routine surgical practice in the near future. The usefulness of surgical telementoring has been greatly enhanced by the development of a technique to illustrate on video images from two directions. Moreover, remote advisory surgeons will be able to provide the optimal operative field to operating surgeons using robotic camera holders with voice-recognition systems. In the near future, when master-slave manipulators will also be coupled with telementoring systems, remote experts could actually perform complex surgical procedures.

Humans↗
PubMed2002

[A comparison of master eye operation with slave eye operation on patients with large-angle exotropia].

OBJECTIVE: To search for an excellent therapy for patients with large-angle exotropia. METHODS: Strabotomy was performed on the master eyes in the 41 cases (master eye group) and slave eyes in the other 41 cases (slave eye group) with large-angle exotropia (>/= 60(Delta)). The post-operative visual acuity, ocular position, visual function and fixation, the average surgical amount and the frequency of strabotomy were statistically compared between the two groups. RESULTS: Post-operatively, orthophoria occurred in 39 cases and mild exotropia remained in 2 cases in each group. The statistic analyses showed that the surgical results were better in the master eye group in the visual acuity (P < 0.05), visual function (P < 0.05), average surgical amount and frequency (P < 0.01). CONCLUSIONS: The surgical results of strabotomy performed on the master eye in cases with large-angle exotropia are better than that on the slave eye, and the surgical damage in the master eye is less. Thus, the master eye strabotomy is especially suitable for children with large-angle exotropia under general anesthesia.

Adolescent↗
PubMed2005

Reproductive conflict in social insects: male production by workers in a slave-making ant.

In insect societies, workers cooperate but may also pursue their individual interests, such as laying viable male eggs. The case of obligatory slave-making ants is of particular interest because workers do not engage in maintenance activities and foraging. Therefore, worker egg laying is expected to be less detrimental for colony efficiency than in related, nonparasitic species. Furthermore, as slave-making workers usually do not perform brood care and thus might have little power in manipulating sex allocation, they might be more strongly selected to increase their direct fitness by producing their own sons than workers in nonparasitic species. In this study we investigated worker reproduction in four natural colonies of the slave-making ant Polyergus rufescens, using highly variable microsatellite markers. Our results show that workers produce up to 100% of the males. This study thus presents the first direct evidence of an almost complete takeover of male reproduction by workers in ants.

Animals↗
PubMed1987

Implications of tooth root hypercementosis in a Barbados slave skeletal collection.

A 17th- to 19th-century cemetery sample of 104 slaves from Newton Plantation (Barbados) shows uniquely high hypercementosis prevalence, as well as unexpectedly high and variable skeletal lead content. A variety of biological and archeological factors indicates that individuals with lower amounts of these anomalies (relative to age at death) were probably African-born, first-generation slaves. The hypercementosis is related to the progression of periodontal disease as assessed from alveolar bone. Although the hypercementosis is endemic in the Caribbean black population, it does not as yet have a clear explanation. We suggest the etiology might relate to chronic malnutrition involving periodic, seasonal rehabilitation.

Black or African American↗
PubMed1989

Small tooth sizes in a nineteenth century South Carolina plantation slave series.

Sub-Saharan African (and derived) populations typically exhibit larger mean tooth crown diameters than whites in spite of considerable population variability. We report on a 19th century series of American black slaves from a single cemetery near Charleston, South Carolina, that possessed notably smaller crown sizes. Analysis identifies a characteristic set of differences compared to caucasians, including retention of large maxillary lateral incisors and disproportionately large premolars and molars. Regression of principal components scores (derived from the mesiodistal diameters) on the sum of all diameters (used here as a measure of overall tooth mass) confirms a basic ethnic difference between black and white odontometrics: significantly more of the tooth mass is apportioned to the cheek teeth (premolars, molars) in blacks than whites. The difference (expressed as residuals from linear regression on tooth mass) holds for the several groups assessed here despite considerable intergroup variability in tooth sizes. Potential explanations for the notably small diameters of this plantation series are speculative, but may involve kin-based divergences and/or reflect the natural intergroup differences extant in the African slave sources.

Adult↗
PubMed1993

Transcriptional entrainment between master-slave genes via sister chromatid exchanges.

The paper discusses a mechanism for the coordination of a differentiation path through activation of slave genes by transcriptional complexes (excitons) organised by master genes. Entrainment occurs when master-slave genes form partnerships of closely apposed entities. Sister chromatid exchanges provide the action necessary for successful entrainment. Although concerned mainly with normal hematopoietic (stem) cells, the model applies also to certain leukemic cells, regarding in particular retrodifferentiation back to the stem state followed by attenuation of malignancy.

Animals↗
PubMed2003

Native American Y chromosomes in Polynesia: the genetic impact of the Polynesian slave trade.

Since Thor Heyerdahl asserted that Polynesia was first colonized from the Americas (Heyerdahl 1950), geneticists have sought--but have not found--any evidence to support his theories. Here, Native American Y chromosomes are detected on the Polynesian island of Rapa. However, this, together with other odd features of the island's Y-chromosomal gene pool, is best explained as the genetic impact of a 19th century Peruvian slave trade in Polynesia. These findings underscore the need to account for history before turning to prehistory and the value of archival research to understanding modern genetic diversity. Although the impact of the Atlantic slave trade on the distribution of modern genetic diversity has been well appreciated, this represents the first study investigating the impact of this underappreciated episode on genetic diversity in the Pacific.

Chromosomes, Human, Y↗
PubMed2001

Coevolution in host-parasite systems: behavioural strategies of slave-making ants and their hosts.

Recently, avian brood parasites and their hosts have emerged as model systems for the study of host-parasite coevolution. However, empirical studies of the highly analogous social parasites, which use the workers of another eusocial species to raise their own young, have never explicitly examined the dynamics of these systems from a coevolutionary perspective. Here, we demonstrate interpopulational variation in behavioural interactions between a socially parasitic slave-maker ant and its host that is consistent with the expectations of host-parasite coevolution. Parasite pressure, as inferred by the size, abundance and raiding frequency of Protomognathus americanus colonies, was highest in a New York population of the host Leptothorax longispinosus and lowest in a West Virginia population. As host-parasite coevolutionary theory would predict, we found that the slave-makers and the hosts from New York were more effective at raiding and defending against raiders, respectively, than were conspecifics from the West Virginia population. Some of these variations in efficacy were brought about by apparently simple shifts in behaviour. These results demonstrate that defence mechanisms against social parasites can evolve, and they give the first indications of the existence of a coevolutionary arms race between a social parasite and its host.

Animals↗
PubMed2006

Robustly stable adaptive control of a tandem of master-slave robotic manipulators with force reflection by using a multiestimation scheme.

The problem of controlling a tandem of robotic manipulators composing a teleoperation system with force reflection is addressed in this paper. The final objective of this paper is twofold: 1) to design a robust control law capable of ensuring closed-loop stability for robots with uncertainties and 2) to use the so-obtained control law to improve the tracking of each robot to its corresponding reference model in comparison with previously existing controllers when the slave is interacting with the obstacle. In this way, a multiestimation-based adaptive controller is proposed. Thus, the master robot is able to follow more accurately the constrained motion defined by the slave when interacting with an obstacle than when a single-estimation-based controller is used, improving the transparency property of the teleoperation scheme. The closed-loop stability is guaranteed if a minimum residence time, which might be updated online when unknown, between different controller parameterizations is respected. Furthermore, the analysis of the teleoperation and stability capabilities of the overall scheme is carried out. Finally, some simulation examples showing the working of the multiestimation scheme complete this paper.

Algorithms↗
PubMed1999

Effects of head-slaved and peripheral displays on lane-keeping performance and spatial orientation.

To improve the efficiency of images presented in low-cost vehicle simulators, the virtual viewing direction (i.e., the direction in which the image is rendered) can be head-slaved, the display can be surrounded with a less detailed peripheral image, or both. Three simulator experiments were used to evaluate the effect of these techniques on lane-keeping performance and spatial orientation. In Experiment 1, vehicle references or a head-slaved display (HSD) provided feedback on the virtual viewing direction. Vehicle references improved lane-keeping performance somewhat with a standard 50 degrees h x 50 degrees v display. An HSD (50 degrees h x 50 degrees v) allowed better steering performance, but not to the levels obtained with a wide display (150 degrees h x 50 degrees v). Experiments 2a and 2b evaluated the effects of surrounding the HSD with a less detailed peripheral image and of moving the HSD discretely or continuously. With the peripheral image, lane-keeping performance (Experiment 2a) and spatial orientation (Experiment 2b) were similar to those with a wide display. In both experiments, performance with the discretely moving HSD was superior to that with the continuously moving HSD. The results show that low-cost driving simulators can be equipped with more efficient displays that are as effective as wide displays for lane-keeping and spatial orientation.

Adult↗
PubMedDate not supplied

[The Pharaohs: slave merchants or organizers of an efficient welfare system? Re-writing history through new documentation and research].

The Authors have studied documents dating from the era of the Pharaohs, that is to say: the papyruses of Ebers and Smith, and have come to the conclusion that the recent claims by some archaeologists that the Egyptian workmen who built the Pyramids, were protected by health regulations and not treated as slaves, is true. This is a new interpretation of Egyptian history, because up to now, it has always been thought that the workmen were slaves. The construction of the Pharaoh's tomb was a team work including members of the upper classes (architects, physicians) and the lower classes (masons, workmen) and was the demonstration of a contribution and a symbol of recognition from all members of the team to the head of the society (the Pharaoh), who was their employer and took their interests into consideration e.g. health regulations. The Authors have also deduced from other sources of information that a public health system and welfare organization, comparable to our present day Legislative Decree 626/94, did in fact exist in the ancient world.

Egypt, Ancient↗
PubMed1989

Controversies on the subject of slave-raids in amazon ants (genus Polyergus).

The paper contains a polemic with the view expressed by Talbot, Wilson and Topoff and his co-workers, who maintain that the existence of scouts and their leading directing in slave-raids of the American Polyergus' species is fully proved. In particular we do not agree with Talbot's and Wilson's argument that following by the amazons of the scent-trail prepared from the crushed bodies of their nestmates indicates that the amazon raids follow the trails of scouts. Considering the results and notions of the above-mentioned authors, we maintain that the mechanism of slave-raids in the American amazons is far from clear.

Animals↗
PubMed1992

Congenital syphilis in the past: slaves at Newton Plantation, Barbados, West Indies.

Hutchinson's incisors and Moon's molars are specific lesions of congenital syphilis. The extensive but fragmentary clinical literature on these conditions describes reduced dimensions and thin enamel in the permanent incisors and first molars, crowding and infolding of the first molar cusps, notching of the upper incisors, and apical hypoplasias of the permanent canines. A Barbados slave cemetery (ca. 1660-1820 AD) includes three individuals with these features, suggesting a frequency at birth of congenital syphilis in the population approaching 10%. These three cases show triple the frequency of all hypoplasias and more than seven times the frequency of pitting hypoplasia present in the remainder of the series. The recognizable congenital syphilis cases account for much of the remarkably high frequency of hypoplasias in the series as a whole. We infer that syphilis contributed substantially to morbidity, infant mortality, and infertility in this population. Presence or absence of congenital syphilis may account for much of the variability in health and mortality seen among nineteenth century African-American populations.

Adolescent↗