Search

Se evaluó la precisión y exactitud en la estimación de la grasa corporal (%) por absorciometría dual de rayos X (DXA Lunar-DPX-MD) comparado con el modelo de cuatro compartimentos (4C) en 32 púberes (F=16) de 9 a 14 años. El sesgo entre la DXA y el modelo de 4C fue de -3.5% de grasa (r=0.25; p=0.171) con un intervalo de confianza de -1.9 a -5.1 (p=0.050). Los límites de concordancia al 95% fueron de +5% a -12% de grasa. El coeficiente de correlación de concordancia fue de pc=0.85. La prueba de exactitud por análisis de regresión mostró que el intercepto y la pendiente de las estimaciones de grasa corporal por DXA fueron diferentes al modelo de 4C (p>0.05). La precisión evaluada con el valor de R2 mostró que la DXA explicó el 83% de la varianza de la grasa corporal por el modelo de 4C con un error de 4.1%. El error total como medida de exactitud fue de 5.6%. La exactitud grupal evaluada por análisis de varianza no mostró interacción entre el método (DXA-4C) y el análisis por separado del sexo, el estado puberal y la presencia de sobrepeso. No obstante, hubo efecto del método (p=0.043) en presencia de sobrepeso (pThe objective of this study was to validate the estimation of body fat (%BF) by DXA (Dual-Energy X-Ray AbsorciomDPX-MD) against the four compartment model (4C) of body composition in 32 Mexican pubertal girls and boys (aged 9 - 14y; F=16). The mean of the difference between DXA and 4C model was -3.5 %BF (p=0.171). The limits of agreement (95% ± 2 SD) were +5% to -12%BF. The precision of estimated limits of y the confidence intervals were -1.9% to -5.1%BF (P=0.050). The concordance correlation coefficient was pc= 0.85. The test of accuracy for coincidence of slop intercepts between DXA and the 4C model showed no coincidence (p< 0.05). The precision by R2 explained 83% of the variance (SEE, 4.1 %). The individual accuracy assess by the total error was 5.6%. The group mean accuracy by two way analysis of variance of body fat did not show interaction between method (DXA-4C model) and separate analysis of gender and overweight. However, there was an effect of method (p=0.043) in the presence of overweight (p

Testou-se a hipótese de que animais bem alimentados durante a vida fetal e durante o período pós-parto apresentariam melhor desempenho reprodutivo que aqueles com alimentação restrita durante a vida fetal e/ou no pós-parto, sendo animais com menor idade à puberdade. Utilizaram-se 120 ovelhas Merino Australiano prenhes com 60 dias de gestação, distribuídas em fatorial 2x2, com quatro níveis nutricionais, tendo metade de seus grupos invertidos. Os animais foram pesados no nascimento, e as ovelhas que pariram fêmeas foram eliminadas e os machos identificados por brincos de cores diferentes (laranja, roxo, preto e verde) e distribuídos entre os tratamentos. O escore corporal manteve as mesmas relações observadas para o peso corporal entre os grupos. Os animais de brinco preto apresentaram menor perímetro escrotal aos 132 dias, com maior crescimento escrotal, decorrente da melhora nutricional desses animais em determinados períodos. Como condição de escore corporal, o perímetro escrotal manteve a mesma relação entre os grupos, como observado para o peso corporal, com o grupo laranja com maior perímetro, seguido pelo grupo roxo, pelo verde e pelo preto. Apenas 62,5% dos animais manifestaram puberdade até o final do experimento. Os animais atingiram a puberdade com escore, com perímetro e com idade semelhantes, entretanto tiveram pesos diferentes

he aim of this study was to investigate estrus synchronization in prepubertal and pubertal heifers (crossbred 1/2 Nelore x Red Angus - commercial herd) submitted to a long-term progesterone-based protocol for timed artificial insemination (TAI), as well as overall pregnancy rates. Four hundred forty-seven heifers underwent ultrasound examination of the ovaries and were assigned to one of 3 groups: (1) prepubertal heifers (PPNS; n = 114) with ovarian follicles <8 mm in diameter and no corpus luteum (CL) that were submitted to natural service (NS) by bulls for 10 days; (2) prepubertal heifers (PPTAI; n = 124) with follicles <8 mm in diameter and no CL that underwent estrus synchronization with injection of 4.0 mg estradiol benzoate (EB) and insertion of a controlled-release intravaginal progesterone (P4) device containing 0.558 g P4 on d 0, followed by P4 device removal and injection of 150 mg prostaglandin F2α and 0.6 mg estradiol cypionate (ECP) on d 8, and TAI on d 10; and (3) pubertal heifers (PTAI; n = 209) with follicles >8 mm in diameter and/or a CL that underwent the same protocol as PPTAI heifers. Overall pregnancy rate was determined by transrectal ultrasonography on d 45 after NS or TAI. Data were analyzed using the FREQ procedure of SAS (SAS Inst. Inc., Cary, NC). Pregnancy rates were as follows: 20.1% in PPNS, 37.0% in PPTAI, and 48.5% in PTAI (P < 0.05). In conclusion, TAI after estrus synchronization with a hormonal protocol using EB and ECP in prepubertal and pubertal heifers resulted in higher pregnancy rates than prepubertal heifers exposed to natural service, and exposure of prepubertal heifers to a long-term progesterone-based protocol effectively synchronized estrus. [ABSTRACT FROM AUTHOR]

This paper discusses the results of preliminary research on the representation of old age in children and teenagers. The conjunction of theoretical contributions from social psychology, social representational theory, and developmental psychology allows us to think about the way in which children assimilate the beliefs shared by the community. From a Piagetian approach, the subject builds the object of knowledge conferring different meanings according to each intellectual stage, but also in terms of the meanings assigned by social discourse. This research contributes to the discussion on a problem still open to debate regarding the social construction of knowledge, i.e., how children build and assimilate socially shared knowledge. [ABSTRACT FROM AUTHOR]