2,037 research outputs found
Hands-On Physical Science for In-Service Teachers
The initiation of the Virginia Commonwealth University B.S. in Science program was reported in this journal Fall 1999 as a program designed to meet the academic content major of a teacher preparation program for elementary and middle school mathematics and science teachers [1]. This paper reports the current status of the interdisciplinary B.S. in Science degree program including program enrollment data and trends. Also described are refinements in the required curriculum, which include a newly developed geometry, a mathematical computing course, and an emerging teaching technology course featuring graphing calculators, CBLs, and computer software applications
Early maternal experience shapes offspring performance in the wild
Both the environments experienced by a mother as a juvenile and an adult can affect her investment in offspring. However, the implications of these maternal legacies, both juvenile and adult, for offspring fitness in natural populations are unclear. We investigated whether the juvenile growth rate and adult reproductive traits (length, body condition, and reproductive investment at spawning) of female wild Atlantic salmon (Salmo salar) were related to the growth and survival of their offspring. Adult salmon captured on their upstream migration were used to create experimental full-sib clutches of eggs, which were mixed and then placed in artificial nests in a natural stream that lacked salmon due to a migration barrier. Four months later we resampled the stream to obtain family-level estimates of offspring size and survival. Mothers that had grown slowly as juveniles (as determined by scalimetry) but had invested heavily in reproduction (egg production for a given body length) and were in relatively poor body condition (somatic mass for a given body length) at spawning produced the largest eggs. Larger eggs resulted in larger juveniles and higher juvenile survival. However, after controlling for egg size, offspring growth was positively related to maternal juvenile growth rate and reproductive investment. The predictors of offspring survival (i.e., reproductive success) varied with the juvenile growth rate of the mother: If females grew slowly as juveniles, their reproductive success was negatively related to their own body condition. In contrast, the reproductive success of females that grew quickly as juveniles was instead related positively to their own body condition. Our results show that maternal influences on offspring in the wild can be complex, with reproductive success related to the early life performance of the mother, as well as her state at the time of breeding
Interactions between parental traits, environmental harshness and growth rate in determining telomere length in wild juvenile salmon
A larger body size confers many benefits, such as increased reproductive success, ability to evade predators and increased competitive ability and social status. However, individuals rarely maximise their growth rates, suggesting that this carries costs. One such cost could be faster attrition of the telomeres that cap the ends of eukaryotic chromosomes and play an important role in chromosome protection. A relatively short telomere length is indicative of poor biological state, including poorer tissue and organ performance, reduced potential longevity and increased disease susceptibility. Telomere loss during growth may also be accelerated by environmental factors, but these have rarely been subjected to experimental manipulation in the natural environment. Using a wild system involving experimental manipulations of juvenile Atlantic salmon Salmo salar in Scottish streams, we found that telomere length in juvenile fish was influenced by parental traits and by direct environmental effects. We found that faster-growing fish had shorter telomeres and there was a greater cost (in terms of reduced telomere length) if the growth occurred in a harsher environment. We also found a positive association between offspring telomere length and the growth history of their fathers (but not mothers), represented by the number of years fathers had spent at sea. This suggests that there may be long term consequences of growth conditions and parental life history for individual longevity
Timing of Atlantic salmon Salmo salar smolt migration predicts successful passage through a reservoir
Around 30% of Atlantic salmon Salmo salar smolts successfully survived passage through Loch Meig, a reservoir in the north of Scotland, en route to the sea. However, this survival rate was in turn dependent on the timing of migration, with the earliest migrants in the spring having the best chance of survival. This could have implication for fisheries management, since the estimation of smolt downstream survival may be influenced by which time period of the smolt run is analysed
A Snow-tracking Protocol Used to Delineate Local Lynx, Lynx canadensis, Distributions
Determining Canada Lynx (Lynx canadensis) distribution is an important management need, especially at the southern extent of the species range where it is listed as threatened under the U. S. Endangered Species Act. We describe a systematic snowtrack based sampling framework that provides reliable distribution data for Canada Lynx. We used computer simulations to evaluate protocol efficacy. Based on these simulations, the probability of detecting lynx tracks during a single visit (8 km transect) to a survey unit ranged from approximately 0.23 for surveys conducted only one day after snowfall, to 0.78 for surveys conducted 7 days after a snowfall. If the survey effort was increased to three visits, then detection probabilities increased substantially from 0.58 for one day after snowfall to about 0.95 for surveys conducted 7 days after a snowfall. We tested the protocol in the Garnet Range, Montana, where most lynx were radio-collared. We documented a total of 189 lynx tracks during two winters (2001-2003). Lynx distribution based on snow-track surveys was coincident with the area defined through radio telemetry. Additionally, we conducted snow-track surveys in areas of western Wyoming where lynx were believed present but scarce. We detected a total of six lynx tracks during three winters (1999-2002). In Wyoming , where lynx presence was inferred from a few tracks, we verified species identification by securing genetic samples (hairs from daybeds) along track-lines
Broad-Scale Genetic And Compositional Monitoring Of Aquatic Vertebrate Populations: A Proof Of Concept In The Interior Columbia River And Upper Misouri River Basins
Monitoring fish and amphibian populations is essential for evaluating conservation efforts and the status and trends of individual species, but measuring abundance is time-consuming and problematic at large scales. Also, relations between fish populations and their surrogates, such as habitat characteristics, are often obscure. As an alternative, genetic assessment and monitoring offers promise as an indicator of population status and trends by providing information on genetic diversity, connectivity among populations, and the prevalence of hybridization with non-native species. We have undertaken intensive sampling of native and nonnative fishes and amphibians in streams monitored by the Pacfish/Infish Biological Opinion Monitoring Program, which includes a spatially comprehensive, random sample of subbasins in the interior Columbia River Basin and upper Missouri River Basin. We have also developed a panel of ~100 single nucleotide polymorphism markers for cutthroat trout, redband trout, and rainbow trout to describe patterns of hybridization and landscape genetic structure. If fully realized, analyses of tissues sampled from over 1500 streams in Montana, Idaho, eastern Oregon, and eastern Washington on federal lands should permit broad-scale evaluations of the status and distribution of much of the aquatic vertebrate fauna and enable detection of responses to climate change. Preliminary results of sampling at nearly 700 sites on almost 300 western Montana and northern Idaho streams indicate that westslope cutthroat trout occupy headwater sites in most of their historical range except in the Kootenai and Missouri River basins, brook trout are more widely distributed than previously recognized, and the taxonomic complexity of sculpins is underappreciated
Sustaining entrepreneurial business: a complexity perspective on processes that produce emergent practice
This article examines the management practices in an entrepreneurial small firm which sustain the business. Using a longitudinal qualitative case study, four general processes are identified (experimentation, reflexivity, organising and sensing), that together provide a mechanism to sustain the enterprise. The analysis draws on concepts from entrepreneurship and complexity science. We suggest that an entrepreneur’s awareness of the role of these parallel processes will facilitate their approaches to sustaining and developing enterprises. We also suggest that these processes operate in parallel at multiple levels, including the self, the business and inter-firm networks. This finding contributes to a general theory of entrepreneurship. A number of areas for further research are discussed arising from this result
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