4,656 research outputs found
Large volume hog production in the U.S. : a 1975 survey
Cover title."12/75/2.5M."Includes bibliographical references
Medium size and larger U.S. hog producers
Title from caption.Includes bibliographical references
New Records, Biogeography, and Habitat Protection Needs of Four Species of Potamon (Decapoda: Brachyura) in Greece
Objectives are to determine the occurrence of species of Potamon in eastern Crete and the Aegean Islands (Chios, Naxos, Paros, Mykonos, Tinos and Andros); generate phylogenetic relationships among species to propose a biogeographic hypothesis relative to current distributions of the four species of the freshwater crab genus, Potamon, in Greece; and comment on the need to protect habitat suitable for the survival of species of Potamon in the country. Our collections, made in areas not previously sampled by researchers, indicate the presence of Potamon fluviatile on Tinos, N axos, and Andros, and Potamon potamios from central to eastern Crete; and verified the presence of Potamon ibericum on Chios. Cladistic analyses resulted in a single parsimonious tree (CI=85, RI=75). Potamon in the Balkan peninsula and islands in the Mediterranean region is a monophyletic group composed of two main clades: Clade 1 (P. fluviatile andPotamon algeriense) and Clade 2 (P. ibericum and its sister group composed of Potamon rhodium and Potamon potamios). Vicariant events (e.g. marine transgression and regression, orogeny, volcanism) are hypothesized as major factors that have shaped current distributions of species of Potamon in the Balkan Peninsula, Asia Minor, and the islands of the North Aegean Sea, Eastern Sporades, the Cyclades, and Crete. We recommend an increase in environmental education and communication among older and younger generations, agriculturalists, politicians, policy writers, land developers and economists to create an understanding for the need to protect land and aquatic environments that harbor unique species and the potential benefits for economic activities such as ecotourism. We also recommend the creation of an action plan to develop ecotourism around conservation areas ( e.g. from the source of existing springs downstream for about 200 m before the installation of water withdrawal equipment for irrigation and potable supplies) to generate revenue for funding protection initiatives and to promote green economic development that is ecologically and socio-culturally sustainable
Predicting Fish Species Diversity in Lotic Freshwaters of Greece
Objectives were to test the hypothesis that stream order and stream width alone account for species diversity in drainages of Greece, and to create a mathematical model that predicts fish diversity in small and medium sized freshwater streams in the southern Balkan Peninsula in accord with the stream classification system proposed by the European Environmental Agency (EEA). Thirty-seven species of fishes in 12 families (Petromyzontidae, Anguillidae, Cyprinidae, Moronidae, Centrarchidae, and Blenniidae) were collected in five stream orders (1-5) from 19 river drainages in Greece in 1993 and from 2000-2002. Numbers of species were significantly correlated with stream order (+), width (+), and depth (+), and elevation (-). Results of stepwise regression indicated that stream order, elevation, stream depth, and river km were significant factors associated with ichthyofaunal diversity, and were used to create a regression model to predict species diversity (up to 5th order streams). We conclude that geo-specific factors (i.e., small, isolated drainages with limited water budgets, geological history, dry climate, and low annual rainfall) should be included in the EEA monitoring design for lotic waters in harsh environments of southern Mediterranean countries as these features differ from those of central, eastern, and northern European countries with larger watersheds
Recommended from our members
Oxygen diffusion in Sr<sub>0.75</sub>Y<sub>0.25</sub>CoO<sub>2.625</sub>: a molecular dynamics study
Oxygen diffusion in Sr0.75Y0.25CoO2.625 is investigated using molecular dynamics simulations in conjunction with an established set of Born model potentials. We predict an activation energy of diffusion for 1.56 eV in the temperature range of 1000-1400 K. We observe extensive disordering of the oxygen ions over a subset of lattice sites. Furthermore, oxygen ion diffusion both in the a-b plane and along the c axis requires the same set of rate-limiting ion hops. It is predicted that oxygen transport in Sr0.75Y0.25CoO2.625 is therefore isotropic
Fish Consumption Patterns of Populations in Vicinities of Lake Kastoria and Lake Pamvotis, Greece
Objectives are to establish fish consumption patterns of populations in vicinities of two lakes (Kastoria and Pamvotis) in Greece for use in the assessment of risks associated with consumption of fishes in these agri-chemically impaired lakes. Parameters measured were demographics (i.e., gender, age, weight, education level, occupation, residency), freshwater fish eating frequency, species and sizes of fishes consumed, and fish consumption habits [i.e., quantity, parts, and preparation method). All annual mean site-specific consumption rates of the four gender-age class sub-populations surveyed in vicinity of Lake Kastoria (avg. range= 0.103-0.29 kg/day) exceed those of Greece (0.066 kg/day), EU (0.068 kg/day), Spain (0.104 kg/day), Portugal (0.159 kg/day), and the USEPA default value (0.054 kg/day) with two exceptions. Female consumption rates (0.087-0.103 kg/day) of Perca fluviatilis were below annual consumption rates of Spain and Portugal. Similarly, annual mean site-specific consumption rates of Anguilla anguilla and Cyprinus carpio by male (0.199-0.210 kg/day) and female adults (0.096-0.157 kg/day) in vicinity of Lake Pamvotis exceeded those of Greece, EU, Spain, Portugal, and the USEPA default value. Survey results indicate better-educated Greeks to be higher consumers of fish; however, market availability appears to be a stronger determinant of food choice in comparison to health education. All populations in vicinities of both lakes preferred to eat fried fishes with one exception: grilled C. carpio from Lake Pamvotis was preferred by female and male adults
Influence of retardation effects on 2D magnetoplasmon spectrum
Within dissipationless limit the magnetic field dependence of magnetoplasmon
spectrum for unbounded 2DEG system found to intersect the cyclotron resonance
line, and, then approaches the frequency given by light dispersion relation.
Recent experiments done for macroscopic disc-shape 2DEG systems confirm theory
expectations.Comment: 2 pages,2 figure
Effects of Collection, Transport, and Redeployment Methods on Natural Mortality of Rangia cuneata (Mactridae) Used in Biomonitoring Studies
Sporadic, high mortality in test populations of wedge clams (Rangia cuneata) has limited the potential for using this otherwise desirable test organism in biomonitoring studies. To determine whether high mortality was due to ontogenic or experimental variables, a two-phased study was conducted. In phase I, mortality of collected and re-deployed wedge clams, subjected to varying transport conditions, was determined at 7, 14, 21 and 60 days re-deployment. The use of three transport times (1, 2, 3 hr.), two vehicle conditions (open, closed) and three transport treatments (open, closed, iced containers) yielded 18 test groups. Individual test group mortalities were below 10% through the 21 day re-deployment period and peaked at 13% at the 60 day re-deployment point. The low rates of mortality observed in phase I of this study indicate that reasonable collection and transport of wedge clams does not significantly increase natural mortality and suggests other parameters are more strongly correlated to test population mortality. In phase II of this study, percent survival of collected and acutely redeployed and acclimated redeployed wedge clams was determined. Acclimated re-deployment is the transfer of R. cuneata from saline to freshwater in decrements of 3-4 ppt/day in accord with recommendations in Bedford and Anderson (1972). Acute re-deployment is the placement of R. cuneata in lower salinity waters or freshwater without acclimation. Although percent survival of clams acutely deployed to the freshwater test site was significantly (
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