Silent Spring - the lost call

The "silence" in Rachel Carson's Silent Spring1 alludes to the demise of bird populations through reproductive problems and death resulting from exposure to the pesticides of that time, many of which are endocrine active. Endocrine disrupting chemicals (EDCs) are compounds which may interfere with the endocrine system, producing effects that may disrupt the physiologic function of hormones. Early research on EDC exposure in humans and wildlife has focused mainly on reproductive effects of estrogenic chemicals, however recent studies have revealed that effects of estrogenic as well as non-estrogen active chemicals are often more far reaching than the reproductive system, and even mild exposures experienced early in development may have detrimental effects that are maintained throughout adulthood. Here we show trenbolone acetate, an androgen active environmental contaminant used as a growth promoter for cattle, to cause a literal silence in Japanese quail (Coturnix japonica) chicks following a one time embryonic exposure. Vocalizations were not merely lessened; this is the first study to demonstrate an environmental contaminant to cause a complete abolishment of the ability to vocalize. Since many reasons for vocalization in birds are directly linked to survival of the individual and species, the potential for detrimental population effects is a grave possibility for many avian species that may encounter androgen active chemicals in the environment. Many androgen active EDCs are persistent and ubiquitous in distribution, thereforechances for exposure to these chemicals in birds may be high. We hope that powerful, yet subtle effects like the ones presented here will encourage further research with EDCs to expand beyond the traditional focus of reproductive effects of estrogenic chemicals

The development of vocabulary exercises to accompany social studies textbooks in the intermediate grades.

Thesis (Ed.M.)--Boston Universit

Hotel industry in Boston.

Thesis (M.B.A.)--Boston Universit

The Mexican immigrant, a product of his background

Thesis (M.A.)--Boston University This item was digitized by the Internet Archive

Measuring Tutoring Effectiveness by Program Delivery Model: Small Group Tutoring Compared to Tutoring in Labs in Mathematics, Physics, and Accounting

This study examines the effectiveness of two common tutoring program delivery models by analyzing tutored and nontutored students\u27 grades and semester grade point averages in three subject areas. The effects of gender, age (if 25 years or older), course, duration of tutoring, tutoring contacts, and contacts per week are also measured. The approach to the ex post facto study is quantitative and utilizes data from the Student Information System at Appalachian State University and from tutoring contact sheets. Areas of data presentation include analysis of covariance results for experimental group, gender, age (if 25 years or older), and course; and correlational results for duration of tutoring, tutoring contacts, and contacts per week. Statistical results from this research rejected 10 of the 72 null hypotheses at the $p \u3c .05$ level, and four of the rejected hypotheses were directly linked to the effect of experimental group. Findings showed that students who received tutoring in labs in mathematics and accounting had the highest semester grade point averages, and females earned higher course grades in mathematics and accounting, regardless of whether they were tutored or not. Results also showed that students 25 years or older who were enrolled in a physics course earned higher semester grade point averages as compared to younger students, regardless of whether they were tutored or not. Conclusions of this study emphasize the need for additional research with more students in the subject area of physics and for qualitative approaches to answer the questions of why specific variables were significant. Results and conclusions have applicability for tutoring program administrators in other settings

Synthesis of 3-(Substituted-aryl)-1,2,3,4-oxatriazolium-5-olates As Potential Hypotensive Agents

Hypertension or high blood pressure is a major cause of illness and death in the United States today.1,2 An estimated thirty-six million people suffer from this disease.3 Prolonged hypertension and its attendant strain on various organs may cause heart failure, brain stroke or kidney damage.4 Usually, a pressure of 140/90 mm Hg is taken to be the dividing line between normotension and hypertension.5,6 The hypertensive condition is generally characterized as either primary (essential) hypertension or secondary hypertension.1 A specific cause can be identified in secondary hypertensive patients, such as, pheochromocytoma or adrenal tumor. These causes can typically be corrected by surgery. Essential hypertension occurs in about 90% of the hypertensive population. The etiology of essential hypertension is unknown.1,3,6 The increase in diastolic pressure in primary hypertension may take on either a gradual (benign) or accelerated (malignant) course. The prognosis of gradual hypertension is more favorable than that of the accelerated. Blood pressure in the essential hypertensive patient can almost always be controlled by drug therapy. It is currently accepted that in most hypertensive cases the primary abnormality is due to a high peripheral resistance.7 Numerous biological feedback mechanisms interact in trying to return the body to the normotensive state.8 Some factors involved in the maintenance of homeostasis are central and peripheral sympathetic activity, renal pressor and depressor mechanisms, antidiuretic hormone, sodium balance, baroreceptors, small blood vessel resistance, blood volume and viscosity.1,4,

Planned maintenance systems with respect to modern manufacturing strategies

To remain competitive in todays's increasingly automated environment, manufacturing industry must take a more proactive and strategic attitude towards maintenance. This thesis applies these concepts, as a case study? to Philips Components Durham an advanced manufacturing unit for colour television tubes. Consideration is first given to modern manufacturing strategies and the business objectives which the maintenance strategy must support. Recent organisational changes are then discussed and analysis made of the maintenance information systems infrastructure. Having related the maintenance department functional requirements to proprietary equipment management packages, the area of machine breakdown data collection is further discussed. To address the need for improved feedback on machine performance, a shop floor data collection and analysis system (Equipment Utilisation Improvement system) has been developed and commissioned. This system now provides more accurate and detailed information than was previously available. A further success of this system is that, as a pilot project, the system has highlighted many organisational and technical issues. These must be addressed before a more comprehensive equipment management package could be successfully implemented. Based on the knowledge gained from the implementation of this system, recommendations are made on the responsibilities for maintenance tasks, appropriate training for maintenance personnel and the further development of information systems to support the maintenance function

Friendly Peruasion, Good Salesmanship, or Undue Influence

Undue influence is the substituion of one person\u27s will for the true desires of another. Unlike common persuasion and sale techniques, fraud, duress, threats, or other deceits are often features of undue influence