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Biomedical subjects

J P Masson

Publications and source records attributed to J P Masson.

At least 19 recordsLinked to original sources
PubMed2005

A branching process, its application in biology: influence of demographic parameters on the social structure in mammal groups.

Branching processes are widely used in biology. This theoretical tool is used in cell dynamics, epidemics and population dynamics. In population dynamics, branching processes are mainly used to access extinction probabilities of populations, groups or families, with the Galton-Watson branching process. Many mammal species live in socially-structured groups, and the smallest units of these groups are lineages (or families) of kin-related individuals. In many primate species, these lineages are matrilines, as females remain in their natal groups most of the time, whereas males generally disperse. Lineage parameters, such as numbers of matrilines, size of each matriline and average degree of relatedness, could strongly influence the genetic composition of groups. Evidence indicates that division along matrilines could induce substantial differentiation among fission groups. Here, we develop a novel mathematical model based on the branching process theory describing demographic dynamics of groups. The main result of this model is an explicit analytical expression of the joint distribution of numbers of lineages and sizes of socially-structured groups. We investigated the influence of parameters such as natality and mortality on the outcome of the process, including extinction probability. Finally, we discuss this theoretical result with respect to biological significance.

Animals↗
PubMed1989

[Esthetics in periodontal surgery: description and discussion of an incision and suture technic].

One of the main aspects from a patient's standpoint regarding periodontal therapy is esthetics; the clinician who wants to control the disease by pocket elimination may underestimate this fact. This article describes a conservative surgical approach and a type of modified vertical mattress suture which allows repositioning of soft tissues to a preoperative level. A discussion follows on how such a conservative approach respects the philosophy of modern periodontal therapy.

Epithelial Attachment↗
PubMed1978

[Study of statistical test connections in non-orthogonal analysis of variance].

In the Analysis of Variance, we quite often split up the model to test different hypotheses about the model. However, when we analyse the results, we must not forget that the statistics used for the tests are not stochastically independent, either for an orthogonal design, because the test statistics have the same denominator, or for non-orthogonal design. In the latter case, test statistics have not only the same denominator but also not-independent numerators. The links between test statistics have been studied for orthogonal designs (Dall'Aglio, 1962) and for symmetrical Incomplete Block Design (Ballas and Webster, 1966). We shall give here results for the general case of the Analysis of Variance, treat more particularly the case of the Incomplete Block Design and show the joint distribution of two test statistics and, more simply, their correlation coefficient.

Analysis of Variance↗
PubMed1977

[Lumbar epidural veins. Normal radioanatomy (author's transl)].

Epidural venous system of the human corps are injected by a fortacryl-minium mixture then dissected with detail. These study confirms existence of two longitudinal venous plexus: one anterior and internal, one another anterior and external. There is no posterior longitudinal venous plexus.

Humans↗
PubMed1976

Cavum veli interpositi. Roentgen anatomy - pathology and physiology.

158 pneumoencephalographies of infants less than 2 years old were examined and 53 of them had a large cavum veli interpositi. A neuroradiological description of this cistern is given and a comparison made with injected anatomical specimens. A statistical comparison with 105 pneumoencephalographies without a cavum veli interpositi does not shown any correlation between the presence of this cistern and pathological conditions. This investigation indicates that a large cavum veli interpositi in the newborn has no relation to hydrocephalus or cerebral atrophy. The younger the child, the more frequent is the presence of this cistern, especially under eight months of age.

Brain↗
PubMed1976

[Lumbar epidural veins (anatomic study apropos of 31 cases)].

Using 31 corrosion preparations with fortacryl-minium, a new systematization of lumbar internal vertebral veins is suggested. The classical posterior longitudinal vein was not found. An anterior-lateral venous flow, composed of an anterior-internal venous canal and of an anterior-external venous canal was described. These venous canals jointly progress along internal face of the pedicle and leave a wider space between them in front of the exit foramina, to allow the passage of roots. The authors then study the transversal veins, the junction of the lumbar column with the sacral column and veins of the exit foramina.

Humans↗
PubMed1975

[Anatomo-radiological study of the spinal venous system of the lumbo-sacral junction].

Transfemoral ascending lumbar catheterization of the epidural veins is a new radiological method in lumbar disk disease. The technique and interpretation of the venogram offer some problems: Origin of ascending lumbar vein and internal vertebral venous structures are variable. The authors use 11 corrosion preparations and 18 venograms for the study of the ascending lumbar vein and internal vertebral venous system.

Humans↗