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J M Mateo

Publications and source records attributed to J M Mateo.

5 recordsLinked to original sources
PubMed2000

Kin recognition and the 'armpit effect': evidence of self-referent phenotype matching.

In species with multiple paternity or maternity, animals may best assess their relatedness to unfamiliar conspecifics by comparing their own phenotype(s) with those of unidentified individuals. Yet whether animals can recognize kin through self-matching is controversial. Because golden hamsters (Mesocricetus auratus) mate multiply and can produce multiply sired litters, they were tested for their ability to use self-matching for kin recognition. Hamsters that were reared only with non-kin since birth responded differentially to odours of unfamiliar relatives and non-relatives. Postnatal association with kin was not necessary for this discrimination. Prenatal learning was unlikely because of delayed production and perception of social odours. To our knowledge, this is the first demonstration that a vertebrate can use its own phenotype for kin-recognition purposes without prior experience with kin. By using itself as a referent, rather than its siblings or parents, a golden hamster may be better able to direct nepotism towards the most appropriate individuals. Kin discrimination via self-inspection may be especially important in nepotistic contexts (to identify most closely related conspecifics), whereas inclusion of the phenotypes of close kin as referents may be favoured in mate-choice contexts (to identify all related individuals).

Animals↗
PubMed1996

Early auditory experience and the ontogeny of alarm-call discrimination in Belding's ground squirrels (Spermophilus beldingi).

Because young ground squirrels are vulnerable to predation, selection would favor the early ability to respond to alarm calls. This requires discrimination of classes of alarm calls from each other as well as from non-alarm calls. Pre-emergent auditory experience may influence the development of discrimination. As a means of determining when Belding's ground squirrels (Spermophilus beldingi) can discriminate among calls, cardiac responses to alarm calls and control stimuli were recorded from 2 rearing groups that differed in the frequency of alarm-call exposure. Results suggest that before natal emergence, young can discriminate between 2 classes of alarm calls but they may not discriminate these calls from control stimuli. No differences in responses were found between the rearing groups; thus experience with calls may not influence the onset of discrimination. Early discrimination may facilitate the rapid development of post-emergent behavioral alarm-call responses.

Aging↗
PubMed1994

Sexual maturation in male prairie voles: effects of the social environment.

The effects of various social contexts on sexual maturation in captive male prairie voles were investigated. Sexual maturity was assessed as the ability of a young male to produce urine capable of activating a diestrous adult female into estrus, as females remain anestrus until they ingest a male urinary chemosignal. In five experiments the postweaning social environments of developing males were manipulated (e.g., presence or absence of dam, sire, or junior litter, exposure to unfamiliar adult voles, social isolation) to determine if the age at which males begin to produce potent urine was sensitive to social effects. In general, there was no difference in the age of potent urine production as a function of social environment. Findings are discussed in the context of dispersal, inbreeding avoidance, and mate acquisition.

Animals↗
PubMedDate not supplied

Innovative new concepts in augmentative breast surgery.

The female breast is seen as a badge of feminine beauty in our society. While it can vary over time and with fashions, the perfect breast will always be symmetrically balanced and proportionate to the rest of the body. To create an aesthetic and symmetrically balanced breast using implants to enhance them is not an easy task. Surgery must combine the concepts of an ideal breast with the desires of the patient in terms of size. The satisfactory breast should remain soft, well positioned, and mobile to respond to gravity and postural changes. In attempting to construct an "ideal breast," certain basic aesthetic anatomical proportions should be taken into account: natural positioning of the breast in the thorax; symmetry; the position of the nipple-areola complex as the focal point of the breast in the frontal view; a side profile of the breast with a natural soft fall; and, overall, the position of the new inframammary crease in the standing position, while lying down, and while moving.

Adolescent↗