THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

Agriculture and urban activities are major sources of phosphorus and nitrogen to aquatic ecosystems. Atmospheric deposition further contributes as a source of N. These nonpoint inputs of nutrients are difficult to measure and regulate because they derive from activities dispersed over wide areas of land and are variable in time due to effects of weather. In aquatic ecosystems, these nutrients cause diverse problems such as toxic algal blooms, loss of oxygen, fish kills, loss of biodiversity (including species important for commerce and recreation), loss of aquatic plant beds and coral reefs, and other problems. Nutrient enrichment seriously degrades aquatic ecosystems and impairs the use of water for drinking, industry, agriculture, recreation, and other purposes.

Based on our review of the scientific literature, we are certain that (1) eutrophication is a widespread problem in rivers, lakes, estuaries, and coastal oceans, caused by overenrichment with P and N; (2) nonpoint pollution, a major source of P and N to surface waters of the United States, results primarily from agriculture and urban activity, including industry; (3) inputs of P and N to agriculture in the form of fertilizers exceed outputs in produce in the United States and many other nations; (4) nutrient flows to aquatic ecosystems are directly related to animal stocking densities, and under high livestock densities, manure production exceeds the needs of crops to which the manure is applied; (5) excess fertilization and manure production cause a P surplus to accumulate in soil, some of which is transported to aquatic ecosystems; and (6) excess fertilization and manure production on agricultural lands create surplus N, which is mobile in many soils and often leaches to downstream aquatic ecosystems, and which can also volatilize to the atmosphere, redepositing elsewhere and eventually reaching aquatic ecosystems.

If current practices continue, nonpoint pollution of surface waters is virtually certain to increase in the future. Such an outcome is not inevitable, however, because a number of technologies, land use practices, and conservation measures are capable of decreasing the flow of nonpoint P and N into surface waters.

From our review of the available scientific information, we are confident that: (1) nonpoint pollution of surface waters with P and N could be reduced by reducing surplus nutrient flows in agricultural systems and processes, reducing agricultural and urban runoff by diverse methods, and reducing N emissions from fossil fuel burning; and (2) eutrophication can be reversed by decreasing input rates of P and N to aquatic ecosystems, but rates of recovery are highly variable among water bodies. Often, the eutrophic state is persistent, and recovery is slow.

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Nonpoint pollution of surface waters with phosphorus and nitrogen

Partitioning of Nutrients During Pregnancy and Lactation: A Review of Mechanisms Involving Homeostasis and Homeorhesis

Effects of heat-stress on production in dairy cattle.

Economic losses from heat stress by us livestock industries

Influences of environment and its modification on dairy animal health and production.

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Large Dairy Herd Management

For an evaluation of the effects of heat stress during pregnancy on calf birth weight and postpartum maternal milk yield, 21 cows and 10 heifers were assigned to shade (S; n = 16) or no shade (NS; n = 15) treatments during the last trimester of pregnancy in June 1978. At parturition, all cows were removed from treatment and uniformly managed in the milking herd. At 4-d intervals from d 199 of pregnancy to parturition, respiration rates, rectal temperature, heart rate and Black Globe temperature were recorded and blood samples obtained via tail venipuncture between 1300 and 1600 h. Weekly prepartum body weights of dam, birth weight of calf and subsequent daily milk yield were recorded. Black Globe temperature, rectal temperature and respiration rates were higher in cows given NS. Calf birth weight was lower in the NS group. Milk yield was correlated in a linear manner with calf birth weight, and cows in group NS exhibited reduced lactation performance after calving. Plasma progestin concentrations were higher in heat-stressed cows (6.0 vs 5.1 ng/ml). Estrone-sulfate concentrations were reduced in plasma of NS cows (2,505 vs 4,433 pg/ml). Thus, hormone concentrations of maternal and fetal origin were altered by environment. Plasma thyroxine concentrations were lower in NS cows (51.2 vs 66.4 ng/ml), while plasma triiodothyronine concentrations were elevated (1.8 vs 1.5 ng/ml), indicating altered thyroid hormone metabolism in heat-stressed cows. Heat stress altered endocrine dynamics during pregnancy and reduced calf birth weight and may have indirectly altered subsequent milk yield.

C.J. Wilcox

Papers

Influences of environment and its modification on dairy animal health and production.

Large Dairy Herd Management

Effects of Heat Stress during Pregnancy on Maternal Hormone Concentrations, Calf Birth Weight and Postpartum Milk Yield of Holstein Cows

Effects of climatic and management factors on conception rate of dairy cattle in subtropical environment.

Postpartum estrus as an indicator of reproductive status in the dairy cow.