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At least 37 records · Page 2Linked to original sources
USGS1975

Hepatic microsomal N-oxidation and N-demethylation of N,N-dimethylaniline in red-winged blackbird compared with rat and other birds

Hepatic microsomes prepared from red-winged blackbirds and albino rats were incubated with N,N-dimethylaniline (DMA)_in complete incubation mixtures at pH 7.9 and 37?C for 10 min. Formaldehyde and N,N-dimethylaniline--oxide produced from DMA were measured. Redwings were found to have significantly lower N-demethylation activities than rats, and redwings had only marginal or no N-oxidation activities. Hepatic microsomes from redwings did not further metabolize the N-oxide. The N-oxidation and N-demethylation activities of brown-headed cowbirds, common grackles, and starlings were similar to those of redwings.

Life Sciences↗
USGS2011

The hormonal control of osmoregulation in teleost fish

Hormones are critical to the physiological alterations necessary for ion homeostasis when fish move between freshwater and seawater. Cortisol promotes seawater acclimation through differentiation of salt-secreting mitochondrion-rich cells and ion transport proteins in the gill. The growth hormone/insulin-like growth factor I axis is also important in seawater acclimation and acts in synergy with cortisol. Prolactin (PRL) is important in freshwater acclimation through regulation of ion and water permeability in the gill, gut, and kidney. Cortisol also promotes ion uptake and may interact with PRL during freshwater acclimation. For many species of fish, growth hormone promotes acclimation to seawater, PRL promotes acclimation to freshwater, and cortisol interacts with both hormones, thus having a dual osmoregulatory function.

Life Sciences↗
USGS2015

Quantification of 15 bile acids in lake charr feces by ultra-high performance liquid chromatography–tandem mass spectrometry

Many fishes are hypothesized to use bile acids (BAs) as chemical cues, yet quantification of BAs in biological samples and the required methods remain limited. Here, we present an UHPLC–MS/MS method for simultaneous, sensitive, and rapid quantification of 15 BAs, including free, taurine, and glycine conjugated BAs, and application of the method to fecal samples from lake charr ( Salvelinus namaycush ). The analytes were separated on a C 18 column with acetonitrile–water (containing 7.5 mM ammonium acetate and 0.1% formic acid) as mobile phase at a flow rate of 0.25 mL/min for 12 min. BAs were monitored with a negative electrospray triple quadrupole mass spectrometer (Xevo TQ-S™). Calibration curves of 15 BAs were linear over the concentration range of 1.00–5,000 ng/mL. Validation revealed that the method was specific, accurate, and precise. The method was applied to quantitative analysis of feces extract of fry lake charr and the food they were eating. The concentrations of analytes CA, TCDCA, TCA, and CDCA were 242.3, 81.2, 60.7, and 36.2 ng/mg, respectively. However, other taurine conjugated BAs, TUDCA, TDCA, and THDCA, were not detected in feces of lake charr. Interestingly, TCA and TCDCA were detected at high concentrations in food pellets, at 71.9 and 38.2 ng/mg, respectively. Application of the method to feces samples from lake charr supported a role of BAs as chemical cues, and will enhance further investigation of BAs as chemical cues in other fish species.

Journal of Chromatography B: Analytical Technologi↗
USGS2002

Liquid chromatographic determination of florfenicol in the plasma of multiple species of fish

A simple method was developed for determining florfenicol concentration in a small volume (250 μl) of plasma from five phylogenetically diverse species of freshwater fish. Florfenicol was isolated from the plasma matrix through C 18 solid-phase extraction and quantified by reversed-phase high-performance liquid chromatography with UV detection. The accuracy (84–104%), precision (%RSD⩽8), and sensitivity (quantitation limit <30 ng/ml) of the method indicate its usefulness for conducting pharmacokinetic studies on a variety of freshwater fish.

Journal of Chromatography B: Analytical Technologi↗
USGS2016

Arsenite as an electron donor for anoxygenic photosynthesis: Description of three strains of Ectothiorhodospria from Mono Lake, California, and Big Soda Lake, Nevada

Three novel strains of photosynthetic bacteria from the family Ectothiorhodospiraceae were isolated from soda lakes of the Great Basin Desert, USA by employing arsenite (As(III)) as the sole electron donor in the enrichment/isolation process. Strain PHS-1 was previously isolated from a hot spring in Mono Lake, while strain MLW-1 was obtained from Mono Lake sediment, and strain BSL-9 was isolated from Big Soda Lake. Strains PHS-1, MLW-1, and BSL-9 were all capable of As(III)-dependent growth via anoxygenic photosynthesis and contained homologs of arxA, but displayed different phenotypes. Comparisons were made with three related species: Ectothiorhodospira shaposhnikovii DSM 2111, Ectothiorhodospira shaposhnikovii DSM 243 T , and Halorhodospira halophila DSM 244. All three type cultures oxidized arsenite to arsenate but did not grow with As(III) as the sole electron donor. DNA–DNA hybridization indicated that strain PHS-1 belongs to the same species as Ect. shaposhnikovii DSM 2111 (81.1% sequence similarity), distinct from Ect. shaposhnikovii DSM 243 T (58.1% sequence similarity). These results suggest that the capacity for light-driven As(III) oxidation is a common phenomenon among purple photosynthetic bacteria in soda lakes. However, the use of As(III) as a sole electron donor to sustain growth via anoxygenic photosynthesis is confined to novel isolates that were screened for by this selective cultivation criterion.

Life Sciences↗
USGS1986

Management of the life and death of an earth-science database: some examples from geotherm

Productive earth-science databases require managers who are familiar with and skilled at using available software developed specifically for database management. There also should be a primary user with a clearly understood mission. The geologic phenomenon addressed by the database must be sufficiently understood, and adequate appropriate data must be available to construct a useful database. The database manager, in concert with the primary user, must ensure that data of adequate quality are available in the database, as well as prepare for mechanisms of releasing the data when the database is terminated. The primary user needs to be held accountable along with the database manager to ensure that a useful database will be created. Quality of data and maintenance of database relevancy to the user's mission are important issues during the database's lifetime. Products prepared at termination may be used more than the operational database and thus are of critical importance. These concepts are based, in part, on both the shortcomings and successes of GEOTHERM, a comprehensive system of databases and software used to store, locate, and evaluate the geology, geochemistry, and hydrology of geothermal systems. ?? 1986.

Computers & Geosciences↗
USGS2019

Bayesian statistics for beginners: A step-by-step approach

Bayesian statistics is currently undergoing something of a renaissance. At its heart is a method of statistical inference in which Bayes' theorem is used to update the probability for a hypothesis as more evidence or information becomes available. It is an approach that is ideally suited to making initial assessments based on incomplete or imperfect information; as that information is gathered and disseminated, the Bayesian approach corrects or replaces the assumptions and alters its decision-making accordingly to generate a new set of probabilities. As new data/evidence becomes available the probability for a particular hypothesis can therefore be steadily refined and revised. It is very well-suited to the scientific method in general and is widely used across the social, biological, medical, and physical sciences. Key to this book's novel and informal perspective is its unique pedagogy, a question and answer approach that utilizes accessible language, humor, plentiful illustrations, and frequent reference to on-line resources. Bayesian Statistics for Beginners is an introductory textbook suitable for senior undergraduate and graduate students, professional researchers, and practitioners seeking to improve their understanding of the Bayesian statistical techniques they routinely use for data analysis in the life and medical sciences, psychology, public health, business, and other fields.

Book↗
USGS2017

Opinion: Why we need a centralized repository for isotopic data

Stable isotopes encode and integrate the origin of matter; thus, their analysis offers tremendous potential to address questions across diverse scientific disciplines ( 1 , 2 ). Indeed, the broad applicability of stable isotopes, coupled with advancements in high-throughput analysis, have created a scientific field that is growing exponentially, and generating data at a rate paralleling the explosive rise of DNA sequencing and genomics ( 3 ). Centralized data repositories, such as GenBank, have become increasingly important as a means for archiving information, and “Big Data” analytics of these resources are revolutionizing science and everyday life.

Proceedings of the National Academy of Sciences of↗
USGS2017

Science advancements key to increasing management value of life stage monitoring networks for endangered Sacramento River winter-run Chinook salmon in California

A robust monitoring network that provides quantitative information about the status of imperiled species at key life stages and geographic locations over time is fundamental for sustainable management of fisheries resources. For anadromous species, management actions in one geographic domain can substantially affect abundance of subsequent life stages that span broad geographic regions. Quantitative metrics (e.g., abundance, movement, survival, life history diversity, and condition) at multiple life stages are needed to inform how management actions (e.g., hatcheries, harvest, hydrology, and habitat restoration) influence salmon population dynamics. The existing monitoring network for endangered Sacramento River winterrun Chinook Salmon (SRWRC, Oncorhynchus tshawytscha) in California’s Central Valley was compared to conceptual models developed for each life stage and geographic region of the life cycle to identify relevant SRWRC metrics. We concluded that the current monitoring network was insufficient to diagnose when (life stage) and where (geographic domain) chronic or episodic reductions in SRWRC cohorts occur, precluding within- and among-year comparisons. The strongest quantitative data exist in the Upper Sacramento River, where abundance estimates are generated for adult spawners and emigrating juveniles. However, once SRWRC leave the upper river, our knowledge of their identity, abundance, and condition diminishes, despite the juvenile monitoring enterprise. We identified six system-wide recommended actions to strengthen the value of data generated from the existing monitoring network to assess resource management actions: (1) incorporate genetic run identification; (2) develop juvenile abundance estimates; (3) collect data for life history diversity metrics at multiple life stages; (4) expand and enhance real-time fish survival and movement monitoring; (5) collect fish condition data; and (6) provide timely public access to monitoring data in open data formats. To illustrate how updated technologies can enhance the existing monitoring to provide quantitative data on SRWRC, we provide examples of how each recommendation can address specific management issues.

California↗
USGS2010

Southeast Ecological Science Center

Aquatic ecosystems, from deep sea reefs and coastal marshes to freshwater springs and wetlands, are home to diverse assemblages of life. These commercially and ecologically important systems are part of our national heritage, and are often treasured places or refuges that protect rare or threatened species. In the water-rich Southeastern United States, managers face the challenge of understanding how water and land use affect the region's aquatic life. The Southeast Ecological Science Center (SESC) helps address that challenge by providing objective science that can be used to evaluate proposed actions and develop management strategies.

Fact Sheet↗
USGS2005

Geospatial decision support systems for societal decision making

While science provides reliable information to describe and understand the earth and its natural processes, it can contribute more. There are many important societal issues in which scientific information can play a critical role. Science can add greatly to policy and management decisions to minimize loss of life and property from natural and man-made disasters, to manage water, biological, energy, and mineral resources, and in general, to enhance and protect our quality of life. However, the link between science and decision-making is often complicated and imperfect. Technical language and methods surround scientific research and the dissemination of its results. Scientific investigations often are conducted under different conditions, with different spatial boundaries, and in different timeframes than those needed to support specific policy and societal decisions. Uncertainty is not uniformly reported in scientific investigations. If society does not know that data exist, what the data mean, where to use the data, or how to include uncertainty when a decision has to be made, then science gets left out -or misused- in a decision making process. This paper is about using Geospatial Decision Support Systems (GDSS) for quantitative policy analysis. Integrated natural -social science methods and tools in a Geographic Information System that respond to decision-making needs can be used to close the gap between science and society. The GDSS has been developed so that nonscientists can pose "what if" scenarios to evaluate hypothetical outcomes of policy and management choices. In this approach decision makers can evaluate the financial and geographic distribution of potential policy options and their societal implications. Actions, based on scientific information, can be taken to mitigate hazards, protect our air and water quality, preserve the planet's biodiversity, promote balanced land use planning, and judiciously exploit natural resources. Applications using the GDSS have demonstrated the benefits of utilizing science for policy decisions. Investment in science reduces decision-making uncertainty and reducing that uncertainty has economic value.

Boletin Geologico y Minero↗
USGS2026

Future proofing black bass management: Modernizing the fisheries manager’s toolbox

Objectives A number of key factors are important to bass fisheries management. To adapt to a changing socioeconomic landscape and fish practices, bass fisheries managers can learn from past and current actions in an effort to incorporate new tools that are suitable for management in a changing landscape. Methods From existing generalized life cycles of fisheries coupled with the hierarchy of needs model of human development, I developed a life cycle of bass fisheries, which incorporates major trends in bass science, management, and utility over time. By visualizing past trends, one can visualize potential futures from which managers can proactively plan for management. Results The bass fisheries life cycle illustrates the change in perspective over time relative to bass utility in concert with the change in society from colonization to industrialization and modernization. Throughout this life cycle, science has had an interest in defining black bass species, with resolution affecting management. Over time, commercial interests in black bass as a food source predominated, followed by recreational interests. However, at the current stage, black bass fisheries appear to be dominated by two potentially conflicting interests: eradication–control of invasive bass populations and trophy-seeking. Using this model, I identified toolsets for black bass managers to incorporate into their toolboxes for the future. Conclusions The black bass life cycle suggests an increased emphasis in the future on managing for native populations in their natural habitat simultaneously with trophy fish management. In both cases, genetics tools will be necessary to aid their management. New population and habitat assessment tools will also likely be required beyond what has been currently typical. Additionally, human dimensions and conflict resolution skills will further enable black bass managers to work more efficiently in an increasingly dynamic landscape.

North American Journal of Fisheries Management↗
USGS2002

Effects of rearing temperature on immune functions in sockeye salmon (Oncorhynchus nerka)

To determine if the defences of sockeye salmon (Oncorhynchus nerka) raised in captivity are affected by the rearing temperature or their life-cycle stage, various indices of the humoral and cellular immune functions were measured in fish reared at either 8 or 12??C for their entire life-cycle. Measures of humoral immunity included the commonly used haematological parameters, as well as measurements of complement, and lysozyme activity. Cellular assays quantified the ability of macrophages from the anterior kidney to phagocytise Staphylococcus aureus cells, or the activities of certain bactericidal systems of those cells. The T-dependent antibody response to a recombinant 57 kDa protein of Renibacterium salmoninarum was used to quantify the specific immune response. Fish were sampled during the spring and fall of their second, third and fourth years, corresponding to a period that began just before smolting and ended at sexual maturation. Fish reared at 8??C tended to have a greater percentage of phagocytic kidney macrophages during the first 2 years of sampling than the fish reared at 12??C. During the last half of the study the complement activity of the fish reared at 8??C was greater than that of the 12??C fish. Conversely, a greater proportion of the blood leucocytes were lymphocytes in fish reared at 12??C compared to the fish reared at 8??C. Fish reared at 12??C also produced a greater antibody response than those reared at 8??C. Results suggested that the immune apparatus of sockeye salmon reared at 8??C relied more heavily on the non-specific immune response, while the specific immune response was used to a greater extent when the fish were reared at 12??C. Although a seasonal effect was not detected in any of the indices measured, varying effects were observed in some measurements during sexual maturation of fish in both temperature groups. At that time there were dramatic decreases in complement activity and lymphocyte numbers. This study was unique in its scope because it was the first quantitative assessment of salmon immune functions for an entire life-cycle. ?? 2002 Elsevier Science Ltd.

Fish and Shellfish Immunology↗
USGS1993

Understanding our fragile environment; Lessons from geochemical studies

An understanding of our fragile environment can begin with a recognition of the importance of certain elements, commonly called "minerals substances" (such as iron and zinc), in the lives of humans and animals and in the soils that support plants. This recognition is well deserved because these elements are essential for the life or optimum health of an organism. Some elements such as carbon, hydrogen, oxygen, magnesium, potassium, and phosphorus are required in relatively large amounts by organisms. However, others are required in smaller quantities; these are referred to as trace elements. Diseases have been related to the deficiency of about 20 elements in animals and humans and to the deficiency of approximately 13 elements in plants. At the same time, if these and other elements occur in quantities great enough, toxicity can result. An element, or any substance, that occurs in the environment and contains concentrations above what are considered to be background levels may be considered a contaminant. When contaminants occur at levels that are potentially harmful to organisms, they are labeled as hazards. Often the quantitative difference between essential amounts and toxic concentrations of these elements is very small. For example, the trace element selenium is required at a level of no less than 0.4 ppm in the diet of cattle but can be toxic at levels greater than approximately 4ppm. Elements that are required for survival by animals and plants are termed essential, while those not required are nonessential. Trace essential elements such as fluorine, copper, selenium, molybdenum, and others listed in the table on page 1 can be hazardous to life forms if present at high levels. Nonessential heavy metals such as arsenic, lead, mercury, cadmium, and chromium are usually toxic to organisms at much lower levels than trace essential elements. Depending on the association that these nonessential elements may form with natural geologic materials such as organic matter, other elements or minerals, and adsorbers (such as clays), these elements can range from being safe to being extremely toxic. The elemental composition of plants, animals, and humans correlates with the geologic makeup of the Earth, and life has evolved reflecting these natural occurrences. The science of environmental geochemistry examines the interrelationship of life with the physical and chemical Earth.

Circular↗
USGS2006

Response of microbial community composition and function to soil climate change

Soil microbial communities mediate critical ecosystem carbon and nutrient cycles. How microbial communities will respond to changes in vegetation and climate, however, are not well understood. We reciprocally transplanted soil cores from under oak canopies and adjacent open grasslands in a California oak-grassland ecosystem to determine how microbial communities respond to changes in the soil environment and the potential consequences for the cycling of carbon. Every 3 months for up to 2 years, we monitored microbial community composition using phospholipid fatty acid analysis (PLFA), microbial biomass, respiration rates, microbial enzyme activities, and the activity of microbial groups by quantifying 13C uptake from a universal substrate (pyruvate) into PLFA biomarkers. Soil in the open grassland experienced higher maximum temperatures and lower soil water content than soil under the oak canopies. Soil microbial communities in soil under oak canopies were more sensitive to environmental change than those in adjacent soil from the open grassland. Oak canopy soil communities changed rapidly when cores were transplanted into the open grassland soil environment, but grassland soil communities did not change when transplanted into the oak canopy environment. Similarly, microbial biomass, enzyme activities, and microbial respiration decreased when microbial communities were transplanted from the oak canopy soils to the grassland environment, but not when the grassland communities were transplanted to the oak canopy environment. These data support the hypothesis that microbial community composition and function is altered when microbes are exposed to new extremes in environmental conditions; that is, environmental conditions outside of their "life history" envelopes. ?? 2006 Springer Science+Business Media, Inc.

Microbial Ecology↗
USGS2003

Benefits and costs of increased levels of corticosterone in seabird chicks

Seabird chicks respond to food shortages by increasing corticosterone (cort) secretion, which is probably associated with fitness benefits and costs. To examine this, we experimentally increased levels of circulating cort in captive black-legged kittiwake chicks fed ad libitum. We found that cort-implanted chicks begged more frequently and were more aggressive compared to controls. These behavioral modifications must be beneficial to chicks as they facilitate acquisition of food from the parents and might trigger brood reduction and reduced competition for food. Cort-implanted chicks also increased food intake; however, their growth rates were similar to controls. To examine the costs of chronically increased circulating levels of cort, we removed cort implants and, after a 10-day recovery period, tested cognitive abilities of young kittiwakes. We found that the ability of kittiwakes to associate a visual cue with the presence of food in a choice situation was compromised by the experimental elevation of cort during development. To examine the long-term costs of increased levels of cort, 8 months later we tested the performance of the same individuals in a spatial task requiring them to make a detour around a barrier in order to escape from an enclosure. Individuals treated with cort during development took significantly more time to solve this task compared to controls. The results of this study suggest that the adrenocortical response of a developing bird to environmental stressors is associated with both benefits (increased food intake, foraging behavior, and aggression) and costs (low growth efficiency and compromised cognitive abilities later in life). This provides an evolutionary framework for relating juvenile physiological traits to fitness of birds in subsequent life-history stages. ?? 2003 Elsevier Science (USA). All rights reserved.

Hormones and Behavior↗
USGS2007

Diseases of amphibians

The development and refinement of amphibian medicine comprise an ongoing science that reflects the unique life history of these animals and our growing knowledge of amphibian diseases. Amphibians are notoriously fastidious in terms of captive care requirements, and the majority of diseases of amphibians maintained in captivity will relate directly or indirectly to husbandry and management. Investigators have described many infectious and noninfectious diseases that occur among various species of captive and wild amphibians, and there is considerable overlap in the diseases of captive versus free-ranging populations. In this article, some of the more commonly reported infectious and noninfectious diseases as well as their etiological agents and causative factors are reviewed. Some of the more common amphibian diseases with bacterial etiologies include bacterial dermatosepticemia or “red leg syndrome,” flavobacteriosis, mycobacteriosis, and chlamydiosis. The most common viral diseases of amphibians are caused by the ranaviruses, which have an impact on many species of anurans and caudates. Mycotic and mycotic-like organisms cause a number of diseases among amphibians, including chytridiomycosis, zygomycoses, chromomycoses, saprolegniasis, and ichthyophoniasis. Protozoan parasites of amphibians include a variety of amoeba, ciliates, flagellates, and sporozoans Common metazoan parasites include various myxozoans, helminths (particularly trematodes and nematodes), and arthropods. Commonly encountered non-infectious disease etiologies for amphibians include neoplasia, absolute or specific nutritional deficiencies or overloads, chemical toxicities, and inadequate husbandry or environmental management.

ILAR Journal↗
USGS1974

Earthquake prediction; new studies yield promising results

On Agust 3, 1973, a small earthquake (magnitude 2.5) occurred near Blue Mountain Lake in the Adirondack region of northern New York State. This seemingly unimportant event was of great significance, however, because it was predicted. Seismologsits at the Lamont-Doherty geologcal Observatory of Columbia University accurately foretold the time, place, and magnitude of the event. Their prediction was based on certain pre-earthquake processes that are best explained by a hypothesis known as "dilatancy," a concept that has injected new life and direction into the science of earthquake prediction. Although much mroe reserach must be accomplished before we can expect to predict potentially damaging earthquakes with any degree of consistency, results such as this indicate that we are on a promising road.

Earthquake Information Bulletin (USGS)↗