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V Palmer

Publications and source records attributed to V Palmer.

9 recordsLinked to original sources
PubMed1999

Identification of gender in domestic-cat faces with and without training: perceptual learning of a natural categorization task.

Three experiments were conducted to determine whether human observers could identify the gender of 40 domestic cats (20 female, 20 male) depicted in individual color photographs. In experiment 1a, observers performed at chance for photographs depicting whole cats, cat heads (bodies occluded), and cat bodies (heads occluded). Experiment 1b showed that chance performance was also obtained when the photographs were full-face close-ups of the cats. Experiment 2a revealed that even with gender-identification training on 30 (15 female, 15 male) of the 40 face close-ups, observers were unable to generalize their training to reliably identify the gender of the 10 remaining test faces (5 female, 5 male). However, experiment 2b showed that gender-identification training with the 14 most accurately identified faces from experiment 1b (7 female, 7 male) was successful in raising gender identification of the 10 test faces above chance. Experiments 3a and 3b extended this facilitative effect of gender-identification training to a population of animal-care workers. The findings indicate that, with appropriate training, human observers can identify the gender of cat faces at an above-chance level. A perceptual category learning account emphasizing the on-line formation of differentiated male versus female prototypes during training is offered as an explanation of the findings.

Adolescent↗
PubMed1995

Dietary calorie restriction in the Emory mouse: effects on lifespan, eye lens cataract prevalence and progression, levels of ascorbate, glutathione, glucose, and glycohemoglobin, tail collagen breaktime, DNA and RNA oxidation, skin integrity, fecundity, and cancer.

The Emory mouse is the best model for age-related cataract. In this work we compare the effects of feeding a control diet (C) with a diet restricted (R) by 40% relative to C animals. In the R animals, median lifespan was extended by 40%. The proportion of R mice with advanced cataract was lower than C mice as early as 5 months of age. The mean grade of cataract was lower in R animals, beginning at 11 months and continuing until the end of the study. Ascorbate levels in R plasma and liver were 41-56% of C animals. There was no difference between diet groups with respect to lens ascorbate. Aging was associated with a decrease in ascorbate in lenses and kidneys in C and R mice. By 22 months, R animals had 48% higher liver glutathione levels than C mice. Liver glutathione levels were maximal at 12 months. Plasma glucose levels were > 27% lower in R animals at 6.5 and 22 months, and there was a 14% increase in glucose levels upon aging for both diet groups. In R mice, glycohemoglobin levels were 51% lower and tail collagen breaktime was decreased by 40%, even in younger animals. Collagen breaktime increased > 360% upon aging for both diet groups. Rates of production of urinary oxo8dG and oxo8G were higher in R animals compared with C animals, and increased upon aging. C animals exhibited more cancer and dermatological lesions, but less tail tip necrosis and inflamed genitals than R mice. These data allow evaluation of several theories of aging.

Animals↗
PubMed1994

Mullerian-inhibiting substance secretion is delayed in XX sex-reversed dog embryos.

Sertoli cell secretion of Mullerian-inhibiting substance (MIS) begins shortly after testis differentiation. Mullerian ducts regress following MIS exposure during an embryonic critical period. In dogs with XX sex reversal, Mullerian ducts persist in the presence of testicular tissue. This study was conducted to determine whether MIS is present in ovotestes of XX sex-reversed embryos during the period for Mullerian duct regression in normal males. XX sex-reversed embryos and normal littermates were identified by a combination of karyotype and gonadal histology. The degree of regression in the adjacent Mullerian duct was scored. Immunohistochemical staining was used to detect MIS in the contralateral gonad. Testicular differentiation and MIS secretion were identified in XY embryos at all ages studied (35-46 days). Seminiferous tubules were not observed in gonads of embryos at risk of XX sex reversal between 35-38 days (n = 15), but were observed at 40 and 46 days (n = 3). Although positive staining for MIS was observed in ovotestes, adjacent Mullerian ducts persisted. The degree of seminiferous tubule development was reduced and MIS secretion was delayed in ovotestes, compared to normal testes. Mullerian duct persistence in this model is apparently due to an abnormality in the quantity and timing of MIS secretion during embryonic development.

Animals↗
PubMed1993

Cataract incidence and analysis of lens crystallins in the water-, urea- and SDS-soluble fractions of Emory mice fed a diet restricted by 40% in calories.

Restriction of dietary calorie intake is associated with life extension and with the delay of age-related disorders. Preliminary studies demonstrated that by feeding the Emory mouse a diet restricted by 21% in calories cataract and insolubilization of protein could also be delayed. To observe the effects of calorie restriction over prolonged portions of adulthood, Emory mice were fed the control diet (C) or a diet restricted by 40% in calories (R). Feeding the R diet was associated with delayed formation or progress of cataract over virtually the entire second half of life. At 11 months of age, bilateral grade 5 cataracts were present in 17% and 2% of C and R lenses, respectively. At 22 months of age, bilateral grade 5 cataracts were present in 90% and 18% of C and R lenses, respectively. The distribution of alpha-, beta-, and gamma- crystallins in the water-soluble, urea-soluble, and SDS-soluble fractions indicates more similarities than differences between C and R lenses with a specific grade of cataract or of a given age. However, there were significant and abrupt (after grade 4 cataract) losses of particular gamma-crystallins; gamma-crystallins which were not prominent at earlier stages became the major gamma-crystallin moieties. Losses of alpha-crystallins were also noted upon cataract formation or aging in most of the fractions. Aggregates including gamma- and alpha-crystallins also accumulate faster in the C group.

Aging↗