RESUMO-A temperatura retal (TR), freqüência respiratória (FR) e temperatura da superfície corporal (TS) foram avaliadas em vacas ½, ¾ e 7 / 8 Holandês-Zebu (HZ) durante dois verões e dois invernos nos períodos da manhã e da tarde no Município de Coronel Pacheco-MG, Brasil. O objetivo nesta pesquisa foi estimar níveis críticos superiores do índice de temperatura e umidade (ITU) para os grupos genéticos pesquisados. As medidas para análise de correlação e de regressão múltipla entre as variáveis foram obtidas de um grupo de 15 vacas em lactação por estação estudada, sendo cinco de cada um dos grupos genéticos ½, ¾ e 7 / 8 HZ. Os resultados obtidos na análise de correlação evidenciaram que a freqüência respiratória (FR) é um indicador de estresse térmico melhor que a temperatura retal (TR). Com base na TR, foram estimados valores críticos superiores de ITU iguais a 80, 77 e 75 para os grupos genéticos ½, ¾ e 7 / 8 HZ, respectivamente. Considerando-se a FR, os valores críticos superiores de ITU estimados para os referidos grupos genéticos foram 79, 77 e 76, respectivamente. Com base na TS, estimou-se valor crítico superior de ITU igual a 79 para os três grupos genéticos estudados. Vacas do grupo genético ½HZ demonstraram maior tolerância ao calor que as 7 / 8 HZ, enquanto as ¾HZ se situaram em posição intermediária. Palavras-chave: bovinos, fisiologia, índice de conforto ABSTRACT-The objective of this trial was to estimate the upper critical levels of the temperature-humidity index (TUI) measuring morning and afternoon rectal temperature (RT), respiratory rate (RF), and hair coat surface temperature (ST) of ½, ¾ and 7/8Holstein-Zebu (HZ) dairy cows during two consecutive years (two summers and two winters) in Coronel Pacheco, MG, Brazil. Correlation and multiple analysis were determined using data obtained from 15 dairy crossbreed cows/season; five from each genetic group (GG). Results showed that RF was more reliable than RT as an indicator of heat stress based on both correlation and regression analysis. Estimated upper critical values of the TUI were 80, 77, and 75 using RT and 79, 77, and 76 using RF for ½HZ, ¾HZ, and 7/8HZ dairy cows, respectively. When ST was used the estimated upper critical values of the TUI were very similar among the three GG averaging 79. The ½HZ dairy cows were more heat tolerant than those in the 7/8HZ GG while the ¾HZ were intermediate. Introdução Aproximadamente dois terços do território brasileiro estão situados na faixa tropical do planeta, onde predo-minam temperaturas elevadas, como conseqüência da grande intensidade da radiação solar incidente. Em torno de 64% dos bovinos no mundo são criados nessa região. Não obstante, a produtividade é menor que aquela das regiões temperadas, ocorrendo lentas taxas de cresci-mento e baixa produção de leite (Baccari Jr., 1990). Entre as causas desse menor rendimento produtivo, inclui-se o baixo valor nutritivo das pastagens, as doen-ças e parasitas e o estresse por calor (Tizikara, 1985). Esse tipo de estresse provoca redução na produção de leit...

The leaf area measurement is an important parameter in understanding the growth and physiology of a plant. Therefore, this study aimed to develop the best leaf area estimation model for tomato plants grown in plastic greenhouse conditions. The artificial neural network (ANN) and regression analysis techniques were used in the formation of a leaf area estimation model by using the leaf width and leaf length measurements determined by the linear measurement method. The plant material for the study consisted of 420 leaf samples of the Typhoon F1 tomato type grown in plastic greenhouse conditions. In the comparison of the created models according to both methods, the criteria of selecting low values for the root mean square error (RMSE), the mean absolute error (MAE), and the mean absolute percentage error (MAPE), and high value for the determination coefficient (R 2) were taken into account, and the best estimation models were determined. In the comparison made according to these criteria, it was concluded that the error values of the ANN model [R 2 = 0.96, RMSE = 3.30, MAE = 1.94, and MAPE = 0.05] were lower than those of the regression model [R 2 = 0.92, RMSE = 4.71, MAE = 3.31, and MAPE = 0.08], and that the ANN method provided a better fit to the actual values; therefore, the ANN model can be used as an alternative method in estimating the leaf area.

The efficiencies of the two fish passages of River Ceyhan (Turkey) were investigated by using trap catches, external tags (T-bar anchor tags), PIT telemetry and radio telemetry. According to the results of the study, the pool and weir type fish passage were not effective; no fish entered the trap in this fish passage. Further, it was observed that none of the 50 external tagged fishes, 44 PIT-tagged fishes, and 47 radio-tagged fishes passed through this fish passage. A total of 900 Capoeta damascina and 520 Alburnus adanensis entered the trap installed in the vertical slot fish passage. A relationship was found between the gender ratio of the migratory C. damascina and their migration times. Fish passage performance was different according to the applications. These differences in fish passage success among the applications originated from the sizes of the tagged fish. Because the sizes of the radio-tagged fish were much larger than that of the external tagged fish and PIT-tagged fish so the success of the fish passage according to the radio telemetry was estimated higher than that of the other applications. The further passing ratio of the fish over 20 cm in length was higher than that of the small individuals.

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