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Trophic state indexes (TSI) guide management strategies regarding eutrophication control worldwide. Such indexes usually consider chlorophyll-a (Chl-a), total phosphorus (TP), and Secchi disk depth (SDD) as independent variables for estimating aquatic productivity and the degree of impairment. TSIs for each of these components are frequently averaged to produce a single TSI value associated with a trophic state classification (e.g., oligotrophic, mesotrophic, or eutrophic). The potential divergence among equations and classification systems originally developed for temperate lakes or tropical/subtropical reservoirs might be particularly relevant in the tropics, where there is a lack of data and the use of equations originally developed for temperate systems may be inappropriate. We calculated two widely used TSIs for temperate lakes (TSItemp) or tropical reservoirs (TSItrop) and explored the deviations among TSI components in Brazilian reservoirs. When applied to our tropical/subtropical reservoirs, the TSItemp provided a conservative approach, with lower limits anticipating increasing trophic state classification. TSI components for Chl-a and SDD significantly deviated for both sets of equations, and these discrepancies were related to turbidity, water temperature, and cyanobacterial biomass. For TSItemp, but not for TSItrop, TSI values in relation to Chl-a and TP were also significantly different. All such deviations have important management implications especially when Chl-a, TP, and SDD are averaged in a single TSI, representing loss of information and less useful trophic state classifications. Our results demonstrate that tropical water bodies may respond to drivers of eutrophication differently than temperate systems, highlighting the need for more data to better inform management of these understudied ecosystems. As managers collect data from more tropical water bodies, regional models may offer even better understanding of factors influencing trophic state.

Individual Secchi disk measurements (975,760) were gathered from across the United States to understand regional distribution in water transparency. Compiled Secchi disk measurements represented 14,421 US waterbodies. Average water transparency ranged from 3.5 m) were in Alaska, Maine, Montana, New Hampshire, and Vermont. Regional differences in water transparency were identified across the US Environmental Protection Agency ecoregions (Level III), with lower water transparencies occurring in nutrient-rich regions and higher water transparencies occurring in nutrient-poor regions. Reg...

Advances in biological engineering are likely to have substantial impacts on global society. To explore these potential impacts we ran a horizon scanning exercise to capture a range of perspectives on the opportunities and risks presented by biological engineering. We first identified 70 potential issues, and then used an iterative process to prioritise 20 issues that we considered to be emerging, to have potential global impact, and to be relatively unknown outside the field of biological engineering. The issues identified may be of interest to researchers, businesses and policy makers in sectors such as health, energy, agriculture and the environment.

This article builds on a growing literature about collaborative environmental policymaking and assesses its use in relation to a major element of American water pollution policy—the total maximum daily load (TMDL) program. It extends current literature by tying collaborative policymaking to a key element of the federal Clean Water Act and by compiling information on the implementation of actions recommended in TMDL reports. We find that recommendations contained in TMDL reports are being implemented in many—but not all—of the TMDL-limited watersheds in Ohio and West Virginia. In addition, we find that the presence of a collaborative watershed group is positively associated with perceived progress in TMDL implementation. However, we also find that current efforts are far from sufficient, and we suggest that future efforts to understand collaborative watershed management should take account of TMDL processes and the federal policy structures in which they are embedded.

Graphical methods are presented that can identify relationships between the trophic state variables, total phosphorus, total nitrogen, chlorophyll, and Secchi depth. The graphical approach extends the use of empirical models beyond predictions based solely on local data. Instead, the authors suggest comparing the data against an established set of predictive equations. These equations serve as a “standard model” from which deviations can be observed and inter-preted. The goal of the use of deviations from a standard model is to enhance our ability to understand relationships between important nutrient, transparency, and biological variables and to adjust our predictive models and manage-ment decisions accordingly. Examples are given of interpretations of deviations caused by nitrogen limitation, non-algal turbidity, zooplankton grazing, and dissolved water color.

We used three different sizes of trap nets (small, medium, and large sizes of both mesh and throats) sampled at 6-h intervals to determine peak activity time(s) for fish along the deep vegetation line in Sandy Lake, Portage County, Ohio. Over 90% of the total catch comprised bluegill Lepomis macrochirus, largemouth bass Micropterus salmoides, pumpkinseed L. gibbosus, and black crappie Pomoxis nigromaculatus. All four species had their lowest catch per unit effort (CPUE) at night (2200–0400 hours). Different length-classes of pumpkinseeds and black crappies had peak CPUE during different times of the day. Smaller length-classes of all species (i.e., those captured in small and medium trap nets) had peak CPUE during either dawn (0400–1000 hours) or midday (1000–1600 hours), whereas the only piscivores captured in high abundance (black crappies 150–303 mm total length captured in large trap nets) had higher CPUE at dusk (1600–2200 hours) than during any other time of the day. It is possible that the...

This article presents the rationale for and development of the Connected Classroom Climate Inventory (CCCI) designed to measure connectedness among students in the university classroom. The original inventory contained 20 items plus four validity items. Based on factor analysis and reliability analysis, two of the original 20 items were dropped from consideration. The resulting 18‐item CCCI scale was found to contain a single factor, to have an overall reliability of alpha = .94, and to show initial evidence of validity. The CCCI showed no scale score differences among class sections or based on teacher/student sex. These findings and implications for future communication research are discussed.

The Human Genome Project (“HGP-read”), nominally completed in 2004, aimed to sequence the human genome and to improve the technology, cost, and quality of DNA sequencing ( 1 , 2 ). It was biology's first genome-scale project and at the time was considered controversial by some. Now, it is recognized as one of the great feats of exploration, one that has revolutionized science and medicine.

Trap nets of varying design are commonly used to assess fish populations, but the effect of the design on gear selectivity is not well known. In particular, it may be advantageous to use multiple net designs with different mesh and throat sizes to maximize the catch of specific length-classes and to minimize the risk of predation on small fish by larger fish. We compared the species composition, catch rate, and length distribution of fishes caught by three trap net designs with dimensions differing only in mesh size and throat size (0.6-cm delta mesh and 3.8-cm × 3.8-cm square throats, 1.3-cm square mesh and 7.6-cm × 7.6-cm square throats, or 2.5-cm square mesh and 12.7-cm × 12.7-cm square throats). A total of 3,473 fish of 18 species were captured from Sandy Lake, Portage County, Ohio, during 24 sample dates from June to August 1999. The large net design had a significantly higher average number of species captured (mean = 11) than the medium or small net design (means = 9 and 8, respectively). ...

Little is known about nocturnal habitat selection by fishes under the risk of predation. Using a photoperiod of 15 h light : 9 h dark, we quantified the diel use of artificial macrophytes and open water by two size-classes of bluegill Lepomis macrochirus when the open water was empty (control), contained food, or contained both a caged predator and food. Small bluegills (6.2–7.7 cm total length) spent significantly more time in macrophytes in the predator and food treatment than in the control, followed by the food-only treatment. In addition, small bluegills spent significantly more time in macrophytes during the day than at night in all treatments. The frequency with which small bluegills were found in the same location in subsequent observations was significantly higher in the predator and food treatment during the day than in any other treatment and light combination. Large bluegills (10.2–13.0 cm total length) showed no difference in habitat use among treatments but spent significantly less ...

Urinary monitoring of exposed workers by either analytic chemical methods or radioimmunoassay suggests that urinary levels of 2,4-dichlorophenoxyacetic acid (2,4-D) exceeding 30 ppb are indicative of occupational exposure. However, the current methods do not lend themselves to clinical laboratory use in the rural medical setting. The major goal of this project was to provide medical practitioners who care for members of the agricultural community with a cost-efficient way to conduct exposure assessment. This project used a direct 2,4-D enzyme immunoassay (EIA) and measurement of the ratio between 2,4-D-spiked and non-spiked samples of the same urine to quantify 2,4-D levels. This simplified approach minimizes the effects of non-specific interfering substances in urine and eliminates the need for sample extraction and clean-up. Possible urine co-contaminants (2,4-dichlorophenol and 2,5-dichlorophenol) do not significantly interfere with this immunoassay. Twenty-two forest pesticide applicators who apply and use chlorophenoxy herbicides in their work and 14 comparable control subjects were studied to validate the assay in the occupational setting. Coded urine specimens were examined for levels of 2,4-D by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and compared with immunoassay results from the same specimens. A correlation coefficient of r = 0.982 with a P value of .0001 for a plot of HPLC-MS/MS versus immunoassay demonstrated that the results from these methods were comparable over urinary dose levels ranging from not detectable (

We carried out an experiment to measure the relationship between tensile force in the tendoachilles and plantar fascia strain, and how this relationship is affected by the metatarsophalangeal joint dorsiflexion angle. Eight cadaver lower extremity specimens underwent biomechanical testing. Using a servo-hydraulic testing machine, a tensile force up to 500 N was applied to the tendoachilles while the strain on the plantar fascia was measured using an extensometer. The experiment was repeated at four different metatarsophalangeal joint dorsiflexion angles (0 degrees, 5 degrees, 30 degrees, and 45 degrees). Measurements and calculations showed that dorsiflexion of the toes tightens the plantar fascia (the windlass effect) and increases the effect that a tensile force in the tendoachilles has on the tensile strain and tensile force in the plantar fascia.

This study considered changes in the plankton communities of 50 Adirondack Mountain lakes, along an acidity gradient from pH 7.3 to 4.2. The objective was to test the hypothesis that changes in the biomass of certain species are compensated by opposite changes in the biomass of other species having similar ecosystem functions. This hypothesis was proposed by Frost et al. (1995) ; Linking Species and Ecosystems. Chapman and Hall, NY, pp. 224–239.) and referred to as `complementarity'. Results from the multi-lake survey, as well as data from two experimental studies, provide support for the hypothesis. With increasing acidity, there were declines in the number of plankton species, and pronounced changes in taxonomic composition. There were also reductions in food web complexity, measured as number of trophic links per species. The most acidic lakes displayed extreme dominance of a few taxa per trophic level, and characteristic acid-tolerant species such as Diaptomus leptopus (a calanoid copepod), Keratella taurocephala (a rotifer), and Chlamydomonas sp. (a chlorophyte alga). In contrast, the total biomass of producers and herbivores was unrelated to lakewater acidity. Acid lakes contained levels of phytoplankton biomass (chlorophyll a ) consistent with measured levels of nutrients, and zooplankton biomass was consistent with its resource base (the phytoplankton). Experimental results indicated that complementary changes can occur rapidly at lower trophic levels when replacement species are already present in the community.

A simple and easy to use system has been developed for rapid screening of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) in a variety of situations. The system uses a competitive inhibition Enzyme ImmunoAssay (EIA) based on a previously described mouse monoclonal antibody which is specific for 2,3,7,8-TCDD and related congeners. Two formats have been developed, a rapid tube test and a microplate test. Respective sensitivities are 100 pg/tube and 25 pg/well of 2,3,7,8-TCDD. Congener specificity of the tube test roughly correlates with 1-TEF. The concept of TEQ screening is validated by comparing TEQ values for a set of soil samples to the EIA responses predicted for those samples. Actual analysis of crude extracts of some of the same soils indicated some clean-up is required to remove interferences. Rapid extraction and sample clean-up methods for soil and other matrices are being developed. Potential implementation of the EIA in a fixed lab is discussed. The EIA system offers significant improvements in speed, sample throughput, and cost compared to GC-MS. This system should be useful for screening environmental samples in many situations.

This study reports on relationships between teachers' immediacy and students' evaluations of the course and teacher, and differences among these variables based on teachers' and students' gender. Analysis showed that for 197 undergraduate students (105 women and 92 men) immediacy, course evaluation, and evaluations of their teachers (104 men and 92 women) were positively correlated. There were no differences by gender for immediacy, but three gender differences were found—female instructors received higher teacher and course ratings than their male peers, and female students with male instructors rated the course lower than any other gender grouping.

Polychlorinated biphenyls (PCBs) are ubiquitous environmental pollutants with diverse toxic, teratogenic, reproductive, immunotoxic, and tumorigenic effects. Three of the least abundant of the 209 PCB isomers (congeners) are the most toxic and most difficult to quantify. These are 3,4,3',4'-tetrachlorobiphenyl, 3,4,3',4',5'-pentachlorobiphenyl, and 3,4,5,3',4',5'-hexachlorobiphenyl (IU-PAC No. 77, 126, and 169, respectively). An immunizing hapten was designed to retain the 3,4,3',4' chlorine-substitution pattern and coplanarity characteristic of these toxic congeners. The optimal competitors for immunoassay were weaker binding distinctive single-ring fragments of the PCBs. A monoclonal antibody designated S2B1 was derived and used in direct (antibody-capture) competitive enzyme immunoassays (EIAs). The EIAs are highly specific for non-ortho-substituted congeners and do not recognize the more prevalent but much less toxic noncoplanar PCB congeners or 2,3,7,8-tetrachlorodibenzo-p-dioxin, 2,3,7,8-tetrachlorodibenzofuran, or dichlorobenzenes. Hapten and competitor design for this assay suggests a basis for development of sensitive EIAs for other classes of PCB congeners.

In this article, the researchers investigate reliability and validity of a variety of speech evaluation instruments used in public speaking classes. Raters from diverse backgrounds and experience evaluated videotaped speeches using various evaluation forms. Results indicate student speeches can be evaluated reliably and validly using any of a number of different evaluation forms that address the fundamental speech constructs of content and delivery. In addition, lack of extensive rater training and experience do not appear to have a major negative impact on the evaluation process.

Trihalomethanes (THMs) form when chlorine reacts with certain naturally-occurring organic molecules (THM precursors) during the disinfection of drinking water. THMs are believed to have significant carcinogenic and mutagenic properties. The elucidation of THM precursor sources is important because source management may lower costs and increase effectiveness of in-plant treatments. This study investigated the importance of lake and reservoir sediments as a THM precursor source. Sediments collected from littoral and profundal areas of Lake Rockwell Reservoir (Portage County, Ohio) and from a nearby natural lake (East Twin Lake) were kept in the dark for 21 days at 20°C to estimate release rates of THM precursors. All sediments had significant THM precursor releases relative to non-sediment controls. Anaerobic conditions produced significantly less precursors than during an aerobic incubation. Littoral sediment precursor release rate (μg THMs/m2/day) was significantly greater than precursor release rates for lake and reservoir profundal sediments. The importance of sediment THM precursor release relative to other sources is discussed.

College students enrolled in either an introductory level computer course or a basic public speaking course completed the Computer Attitude Scale (measuring computer anxiety, liking, confidence, and usefulness) and the Personal Report of Communication Apprehension — 24 (a measure of communication apprehension) during the first and last weeks of a semester. Pre-and post-course measures were obtained from 181 students (90 speech and 91 computer students). Among the major results of the study were the following. A small significant positive relationship ( r = .22) was found between computer anxiety and communication apprehension. The examined introductory computer and public speaking courses appear to have no effect on common elements between the two types of anxiety. However, completion of the basic public speaking course lowered communication apprehension; completion of the basic computer course increased computer anxiety. A recommendation is made that the issue of anxiety be acknowledged and addressed in introductory computer courses.

This paper describes the construction of a combinatorial artificial receptor array (CARA) and the application of the array to differentiation of proteins based on their binding patterns. Microarrays displaying 5035 unique binding environments were prepared using a library of 19 small molecule building blocks. Each building block was equipped with a carboxylic acid handle, allowing mixtures of the building blocks to be spotted onto the surface of an amine functionalized glass slide for covalent immobilization as subunits of the binding environments. This strategy employs the microarray surface as the receptor synthesis platform, which allows for flexibility in array preparation and agility in application. An advantage of the CARA strategy is the enormous flexibility it enables in the construction of alternate microarray configurations, which facilitates rapid access to the breadth and depth of binding space. Four fluorescently labeled proteins, ubiquitin, myoglobin, alpha-1-acid glycoprotein and lysozyme, were incubated with the arrays to demonstrate the reproducibility of binding and the level of differentiation that can be achieved. The binding environments are stable, scalable, and adaptable to other formats.

The work of Lee Shulman and his colleagues in the Teacher Assessment Program, supported by the Carnegie Corporation, has led to new conceptions of teaching and teacher assessment (Shulman, 1986, 1987a, 1987b). A key feature of these new conceptions is the proposition that pedagogical content knowledge is an important category of the knowledge base for teaching (Shulman, 1987a). This article describes some issues related to the development of test items to assess pedagogical content knowledge for an elementary teacher licensure test, the Connecticut Elementary Education Certification Examination. Following a brief description of the exam, pedagogical content knowledge is defined. Next is a discussion of three issues that arose when attempting to develop a teacher licensure test that includes assessment of pedagogical content knowledge. Finally, a number of item types that seem to be useful for assessing pedagogical content knowledge are described briefly.

The ecoregion concept is a popular method of understanding the spatial distribution of the environment', however, it has yet to be adequately demonstrated that the environment is distributed in accordance with these bounded units. In this paper, we generated a testable hypothesis based on the current usage of ecoregions: the ecoregion classification will allow for discrimination between lakes of different water quality. The ecoregion classification should also be more effective better than a comparably scaled classification based on political boundaries, land-use class, or random grouping. To test this hypothesis we used the Environmental Monitoring and Assessment Program (EMAP) lake water chemistry data from the northeast United States. The water chemistry data were reduced to four components using principal component analysis. For comparison to an optimal grouping of these data we used K-means cluster analysis to define the extent at which these lakes could be segregated into distinct classes. Jackknifed discriminant analysis was used to determine the classification rate of ecoregions, the three alternative spatial classification methods, and the clustering algorithm. The classification based on ecoregions was successful for 35% of the lakes included in this study, in comparison to the clustered groups accuracy of 98%. These results suggest that the large scale spatial distribution of ecosystem types is more complicated than that suggested by the present ecoregion boundaries. Further tests of ecoregion delineations are needed and alternative large-scale management strategies should be investigated.

During a 12-year period in which 878 hallux valgus corrections were performed, 18 patients (21 feet) with symptomatic hallux valgus deformity and an increased distal metatarsal articular angle (DMAA) underwent periarticular osteotomies (double or triple first ray osteotomies). They were studied retrospectively at an average follow-up of 33 months. The surgical technique comprised a closing wedge distal first metatarsal osteotomy combined with either a proximal first metatarsal osteotomy or an opening wedge cuneiform osteotomy (double osteotomy). When a phalangeal osteotomy was added, the procedure was termed a "triple osteotomy." The average age of the patients at the time of surgery was 26 years. At final follow-up, the average hallux valgus correction measured 23 degrees and the average 1-2 intermetatarsal angle correction was 9 degrees. The DMAA averaged 23 degrees preoperatively and was corrected to an average of 9 degrees postoperatively. One patient developed a postoperative hallux varus deformity, and one patient developed a malunion, both of which required a second surgery. A hallux valgus deformity with an increased DMAA can be successfully treated with multiple first ray osteotomies that maintain articular congruity of the first metatarsophalangeal joint.

To determine the distribution and extent of myocardial edema resulting from ischemia and reperfusion, seven open-chest dogs underwent occlusion of the left circumflex coronary artery for 2 hours (group I), and 10 underwent occlusion for 2 hours and reperfusion for 2 hours (group II). Proton nuclear magnetic resonance spectroscopy (T1 and T2 relaxation times) and percent water content were determined to quantitate the amount of edema. There was a transmural increase of the T1 relaxation time of the central ischemic zone in groups I and II, although this increase was significantly greater in group II in both the subendocardium (group I = 707.8 +/- 12.5 msec, group II = 813.2 +/- 36.2 msec; p less than 0.01) and subepicardium (group I = 641.7 +/- 20.5 msec, group II = 760.5 +/- 34.7 msec; p less than 0.01). These increases were also observed in the T2 weighted relaxation time in the subendocardium (group I = 54.7 +/- 0.8 msec, group II = 78.7 +/- 6.3 msec; p less than 0.005) and subepicardium (group I = 54.0 +/- 1.4 msec, group II = 73.1 +/- 4.0 msec; p less than 0.001). Transmural differences were evident between the myocardial layers with increased T1 relaxation times (p less than 0.01) in the subendocardium in both groups. Similar increases were noted in the percent water content of the myocardium. Thus T1 and T2 relaxation times lengthened with an increase in myocardial water content following occlusion, and these relaxation times were augmented by reperfusion. We conclude that ischemia-induced edema occurs in a transmural distribution from subendocardium to subepicardium following occlusion, and this edema is further enhanced by reperfusion.

(1992). Global Freshwater Quality: A First Assessment. Transactions of the American Fisheries Society: Vol. 121, No. 1, pp. 141-141.

High-performance liquid chromatography has been used to study isoflavonoid accumulation in copper(II) chloride stressed Pisum sativum . Liquiritigenin, isoliquiritigenin, formononetin, pseudobaptigenin, afrormosin and anhydropisatin have been identified in addition to the pterocarpan phytoalexin pisatin. The relationships of these metabolites to isoflavonoid biosynthesis and stress response in pea are discussed.

Trophic state is fast becoming a nonconcept because of the confusion over its proper definition. The lack of agreement to trophic definition stems from its early typological origins, the fusion of causal factors with the resulting biological condition, and the assumption of the complex nature of the concept. A medical analogy of obesity is used to illustrate that trophic state can easily and unambiguously be determined by the measurement of plant biomass alone.

Myocardial ischemia may be produced by limitation of blood flow as in abrupt coronary occlusion, termed supply-type ischemia, or by increasing myocardial oxygen demand in the setting of restricted flow, termed demand-type ischemia. To examine the comparative extent and severity of the dysfunction related to both forms of ischemia, we studied anesthetized, open-chest dogs by means of two-dimensional echocardiography and tracer microspheres. Supply-type ischemia was produced by total occlusion of the LCx (n = 7); demand-type ischemia was induced by infusion of dobutamine after creation of a critical LCx stenosis (n = 6). At the time of the production of ischemia, the group with demand-type ischemia had significant increases in both heart rate (p less than 0.05) and mean arterial pressure (p less than 0.05), whereas the group with supply-type ischemia had a decrease in mean arterial pressure (p less than 0.05). Subendocardial blood flow in the LCx region was severely depressed in supply-type ischemia (0.09 +/- 0.04 ml/min/gm) compared to demand-type ischemia (1.04 +/- 0.07 ml/min/gm; p less than 0.01). Although both groups of animals had an abnormality of left ventricular function during ischemia, as determined by two-dimensional echocardiography, the extent of the dysfunction in the group with supply-type ischemia was greater (146 +/- 12 degrees) compared to the group with demand-type ischemia (99 +/- 9 degrees; p less than 0.01). Similarly, the degree of left ventricular dysfunction in the group with supply-type ischemia was greater than that for the group with demand-type ischemia (p less than 0.05). Thus these data suggest that supply-type ischemia produced by coronary occlusion results in a greater extent and degree of left ventricular functional abnormality than pharmacologically induced demand-type ischemia.

Early NTE test-appraisal studies focused only on the extent to which the content covered on a test matched the content of teacher education curricula. Recently, there has been a shift in emphasis from adequacy of preparation, which is now seen by many as irrelevant to establishing the appropriateness of a teacher licensure examination, to job relatedness. The procedures used to collect and analyze job-relatedness judgments in many studies, however, seem designed to yield positive results. Alternative procedures are described in this article. They involve (a) focusing the judgments to be made on necessity for successful job performance, (b) asking for a total-test judgment, and (c) computing an average per-item score. These procedures pose a more rigorous test of a licensure examination's job relatedness. They incorporate the legal and professional requirements for appraising licensure tests, and they yield richer, more meaningful data regarding the appropriateness of using a test as a licensure requirement.

An HPLC study of copper(II) chloride treated Pisum sativum has shown that the cinnamylphenols obtustyrene [E-1-(4-hydroxy-2-methoxybenzyl)-2-phenylethylene] and xenognosin [E-1-(4-hydroxy-2-metboxy-benzyl)-2- (4-hydroxyphenyl)ethylene] as well as the chalcone 4,4′-dihydroxy-2′-methoxychalcone accumulate as de novo metabolites in the stressed plant. This chalcone has not previously been identified from a plant source. The biosynthetic and stress response relationships of these compounds are discussed.

A continuous dose of aluminum sulfate was applied to the Cuyahoga River 500 m upstream of Lake Rockwell, a northeastern Ohio reservoir, to decrease phosphorus loading. After one week of treatment benthic invertebrates were eliminated at a site 60 m downstream from the application site, possibly through toxicity of intermediate forms of aluminum, and/or from oxygen depletion in the floe, catastrophic drift induced by low pH or aluminum toxicity and the treatment acting as a partial barrier to drift. Small numbers of invertebrates returned to the site three weeks after the application was terminated. The alum floe accumulation seemed to favor the re-establishment of oligochaetes. Downstream sites had reduced numbers of invertebrates, particularly chironomids, after five weeks of treatment, perhaps caused by the alum treatment. Continuous applications of alum may be more toxic than single-dose treatments because of the continuous presence of transitory forms of aluminum.

A numerical trophic state index for lakes has been developed that incorporates most lakes in a scale of 0 to 100. Each major division ( 10, 20, 30, etc. ) represents a doubling in algal biomass. The index number can bc calculated from any of several parameters, including Secchi disk transparency, chlorophyll, and total phosphorus. My purpose here is to present a new approach to the trophic classification of lakes. This new approach was developed because of frustration in communicating to the public both the current nature or status of lakes and their future condition after restoration when the traditional trophic classification system is used. The system presented hcrc, termed a trophic state index (TSI), involves new methods both of defining trophic status and of determining that status in lakes. All trophic classification is based on the division of the trophic continuum, howcvcr this is defined, into a series of classes termed trophic states. Traditional systems divide the continuum into three classes: oligotrophic, mesotrophic, and cutrophic. There is often no clear delineation of these divisions. Determinations of trophic state are made from examination of several diverse criteria, such as shape of the oxygen curve, species composition of the bottom fauna or of the phytoplankton, conccntrations of nutrients, and various measures of biomass or production. Although each changes from oligotrophy to eutrophy, the changes do not occur at sharply defined places, nor do they all occur at the same place or at the same rate. Some lakes may be considered oligotrophic by one criterion and eutrophic by another; this problem is

This series of studies operationalized the concept of rhetorical sensitivity first discussed by Hart and Burks in 1972. A measuring instrument (RHETSEN) was developed and the attitudes‐toward‐communication held by several thousand individuals were thereby assessed. RHETSEN was found to have sufficient reliability and validity. When a national sample of college students responded to RHETSEN, it appeared that their feelings about encoding messages were related to their various sociocultural backgrounds. When a large group of adult nurses took the test, their responses seemed associated with their particular professional duties and life experiences.

Analysis of stool specimens from a patient with familial coproporphyria by high-performance liquid chromatography revealed that 112 microgram per gram of dry feces (14% of the total porphyrin present) was copper coproporphyrin. Examination of stool specimens from other patients with this disease confirmed the presence of significant amounts of both copper coproporphyrin and coproporphyrin. Further investigation showed that the copper coproporphyrin was probably formed by a nonenzymic incorporation of copper by the coproporphyrin in either the bile or feces.

Water velocity is commonly accepted as a factor in the development of benthic algal mats in streams. Within a stream, two different zones of velocity are observed: the free-water velocity of the open water and the local velocity near the stream substrate. A closed laboratory flume system was used to observe the taxonomic composition of benthic algal mats and corresponding changes in the local velocities under different free-water velocities. As the algal mat developed under each experimental velocity, local velocities diminished and eventually became equal in all sections, while free-water velocities remained different. After a period of maximum taxonomic diversity during the first 2 wk of mat development, taxonomic composition, relative abundance of the taxa, and dry weight biomass became increasingly similar in the three velocity regimes, although the mats appeared different upon casual observation. Differences in composition and morphology in natural algal mats may not result from differences in current velocity, and the idea of a "closed monolayer" algal mat may not be appropriate in all situations.

The reliability of criterion-referenced tests (CRTs) used in health program evaluations can be conceptualized in different ways. Classical conceptualizations of reliability have limited usefulness when applied to health-related CRTs. When a cut-score is set, the test's reliability can be represented as the consistency of mastery/nonmastery classifications. When a cut-score is not set, the size of the standard error of measurement (SEM) of a domain score estimate is a reflection of the test's reliability. Formulas are presented for estimating appropriate SEMsfor CRTs. The SEM can be used in computing confidence intervals for domain score estimates andfor a cut-score.

Eutrophication in lakes and reservoirs is a recreational problem and a drinking water quality problem. A major concern is trihalomethane (THM) formation from the reaction of chlorine, a disinfectant, with organic matter in natural water during drinking water treatment. Trihalomethanes, such as chloroform, are known or suspected carcinogens. Algae and allochthonous humic substances are known contributors to the THM precursor pool. Other in-reservoir precursor sources, macrophytes, and sediments, have not been investigated. The authors examined precursor generation in an Ohio water supply reservoir. A three-year input-output study demonstrated that 30 percent of the precursors entering the treatment plant were generated within the reservoir. Laboratory experiments revealed that macrophytes and sediments produce THM precursors. Estimated THM precursor contributions to the reservoir from macrophyte growth and sediment release were small, but algal productivity and macrophyte decomposition may contrib...

Lake Rockwell provides drinking water to Akron, Ohio. Algae and macrophytes cause increased treatment costs, user complaints, and concerns about water quality standards. The reservoir is very eutrophic. A diagnostic study performed in the laboratory with intact cores taken from littoral and anoxic sediments determined that oxic and anoxic sediments have a very high potential for phosphorus release. Only 19 percent of annual phosphorus external loading occurs between May and October, but apparently this summer loading triggers algal blooms in the upper reservoir that are transported downstream. Winter loading contributes to sediment phosphorus, and thus, to summer internal loading. Preliminary evaluations of proposed management steps revealed that harvesting of Myriophyllum spicatum that included root crown removal produced summer-long biomass control after a single harvest. Water quality deteriorated afterwards, however, suggesting that a late summer harvest might intercept senescence, and would ...