Building consensus for riparian users: toward the twenty-first century

Society\u27s definition of the acceptable use of riparian areas changes over time. Land managers must accept these changes and find ways to help rangeland users work together to develop shared visions for all resources. One approach that has worked for the Oregon Watershed Improvement Coalition (OWIC) is the use of abundance theory and the coalition-building process. Abundance theory focuses attention on the needs of the people and on the importance of understanding one another. This method helps to allay the fear with which many resource users approach on another on resource issues. By using abundance theory and coalition building, OWIC has successfully improved the management and shared vision of Oregon\u27s watersheds and associated riparian areas

Variation in the four-spined stickleback.

Thesis (M.A.)--Boston UniversityThe four-spined stickleback shows a variation of 30-33 vertebrae, 9-14 dorsal fin rays, 7-ll anal fin rays, and 2-6 dorsal spines. No correlation exists between any of the characters except dorsal and anal rays, which are strongly correlated. Vertebrae show a sligltt tendency to decrease in number from north to south, while dorsal and anal rays and dorsal spines vary irregularly throughout the range of the species, with no significant difference between populations at either end of the range. Individual differences, however, are sufficient to divide the species into subspecies and races, using the criteria of modern taxonomists. But the presence of clines, plus the fact, that between any two populations, no matter how divergent, intergrading populations can be found throughout the range of the species, suggests that the variation encountered may be environmental and not genetic. Numerous field and experimental studies, reported in the literature, have revealed many different and often contrasting correlations between environmental factors and meristic characters. Taning (1952) showed that each meristic character in Salmo trutta has its own phenocritical period, and was able to produce a range in means of 3.2 vertebrae in offspring of the same parents by varying the temperature during the phenocritical period. The phenocritical period for anal rays was found to overlap slightly with that of the vertebrae, while dorsal and pectoral rays are determined much later. Taning found that vertebrae, and in part anal rays, are mainly determined genotypically, while dorsal and pectoral rays are determined phenotypically. Heuts (1947) showed that there exists in the European stickleback, Gasterosteus aculeatus, the phenomenon of two adaptive peaks. Natural selection favors those individuals with low mean plate numbers in waters of low salinity, and those with high mean plate numbers at high salinities. Heuts (1949) found that fin ray numbers in both types are similarly modifiable by temperature within their own respective habitats. The findings of Taning and Heuts may help to explain the pattern of variation in Apeltes quadracus. The variation encountered in mean vertebral numbers may be due to the temperature lability of a single genotype, indicating that no intraspecific categories should be recognized. Since dorsal and anal rays are correlated with each other but not with vertebrae or spines, they probably develop at about the same time in ontogeny and may be highly modifiable by temperature. As spines show no correlation with the other characters considered, a different explanation for their variation is offered. Cox (1923) found a distinct correlation between spine number and salinity in Apeltes quadracus in the Maritime Provinces. I have found a similar, though imperfect correlation in several localities, with four-spined individuals more abundant at high salinities, and five-spined individuals predominant at low salinities. A selective mechanism similar to the one described by Heuts is believed responsible, with many-spined individuals being selected for at low salinities, and fewer-spined individuals being favored at high salinities. The explanations offered here are conjectural, and alternatives could be given. Only further study, especially experimental work, may fully explain the variation in Apeltes quadracus. [TRUNCATED

Agriculture and riparian areas

Agriculture has historically been based in the subirrigated riparian ecosystems. Often the engineering and agricultural practices have altered the systems and many of the associated ecological processes. In the Western United States, the most common agricultural practices affecting riparian systems has been livestock grazing. Effects have been both positive and negative. Lack of management has deteriorated many of these systems. Current research has shown what types of management have been successful in allowing grazing by livestock to improve the grazing capacity

Biodiversity as a facet of rangeland research

Biodiversity is only partially a scientific issue. Philosophical and political value systems drive much of the debate and action. Better science would, however, help expose much of what is presently intuitive but may be false. A topic upon which range scientists have much to contribute is how plant diversity relates to successional status of woodlands, grasslands, shrub steppe, and deserts. Correspondence of vegetational change to animal habitats and soil erosion follows. Closer monitoring of large blocks of land under multiple use could lead to a blending of research with management. Definitive understanding of mechanisms will, however, require well-designed manipulated experiments with adequate controls maintained over longer time spans than has been the case in the past

Prevention of infection and disruption of the pathogen transfer chain in elective surgery

The COVID-19 pandemic has caused us all to stop our normal activities and consider how we can safely return to caring for our patients. There are many common practices (such as an increased use of personal protective equipment) which we are all familiar with that can be easily incorporated into our daily routines. Other actions, such as cleaning more surfaces with solutions such as dilute povidone iodine or changing the air filtration systems used within operating room theaters, may require more extensive efforts on our behalf. In this article, we have attempted to highlight some of the changes that arthroplasty surgeons may need to instigate when we are able to resume elective joint arthroplasty procedures in an effort to disrupt the chain of pathogen transfer

Performance of Airborne Precision Spacing Under Realistic Wind Conditions and Limited Surveillance Range

With the expected worldwide increase of air traffic during the coming decade, both the Federal Aviation Administration's (FAA's) Next Generation Air Transportation System (NextGen), as well as Eurocontrol's Single European Sky ATM Research (SESAR) program have, as part of their plans, air traffic management (ATM) solutions that can increase performance without requiring time-consuming and expensive infrastructure changes. One such solution involves the ability of both controllers and flight crews to deliver aircraft to the runway with greater accuracy than they can today. Previous research has shown that time-based spacing techniques, wherein the controller assigns a time spacing to each pair of arriving aircraft, can achieve this goal by providing greater runway delivery accuracy and producing a concomitant increase in system-wide performance. The research described herein focuses on one specific application of time-based spacing, called Airborne Precision Spacing (APS), which has evolved over the past ten years. This research furthers APS understanding by studying its performance with realistic wind conditions obtained from atmospheric sounding data and with realistic wind forecasts obtained from the Rapid Update Cycle (RUC) short-range weather forecast. In addition, this study investigates APS performance with limited surveillance range, as provided by the Automatic Dependent Surveillance-Broadcast (ADS-B) system, and with an algorithm designed to improve APS performance when ADS-B surveillance data is unavailable. The results presented herein quantify the runway threshold delivery accuracy of APS under these conditions, and also quantify resulting workload metrics such as the number of speed changes required to maintain spacing

Genetic and Environmental Contributions to the Association Between Anthropometric Measures and IQ: A Study of Minnesota Twins at Age 11 and 17

Peer reviewe

Hydrodynamic Fin Function of Brief Squid, Lolliguncula Brevis

Although the pulsed jet is often considered the foundation of a squid\u27s locomotive system, the lateral fins also probably play an important role in swimming, potentially providing thrust, lift and dynamic stability as needed. Fin morphology and movement vary greatly among squid species, but the locomotive role of the fins is not well understood. To begin to elucidate the locomotive role of the fins in squids, fin hydrodynamics were studied in the brief squid Lolliguncula brevis, a species that exhibits a wide range of fin movements depending on swimming speed. Individual squid were trained to swim in both the arms-first and tail-first orientations against currents in a water tunnel seeded with light-reflective particles. Particle-laden water around the fins was illuminated with lasers and videotaped so that flow dynamics around the fins could be analyzed using digital particle image velocimetry (DPIV). Time-averaged forces generated by the fin were quantified from vorticity fields of the fin wake. During the low swimming speeds considered in this study [\u3c2.5 dorsal mantle lengths (DML) per second], L. brevis exhibited four unique fin wake patterns, each with distinctive vortical structures: (1) fin mode I, in which one vortex is shed with each downstroke, generally occurring at low speeds; (2) fin mode II, an undulatory mode in which a continuous linked chain of vortices is produced; (3) fin mode III, in which one vortex is shed with each downstroke and upstroke, and; (4) fin mode IV, in which a discontinuous chain of linked double vortex structures is produced. All modes were detected during tail-first swimming but only fin modes II and III were observed during arms-first swimming. The fins produced horizontal and vertical forces of varying degrees depending on stroke phase, swimming speed, and swimming orientation. During tail-first swimming, the fins functioned primarily as stabilizers at low speeds before shifting to propulsors as speed increased, all while generating net lift. During arms-first swimming, the fins primarily provided lift with thrust production playing a reduced role. These results demonstrate the lateral fins are an integral component of the complex locomotive system of L. brevis, producing lift and thrust forces through different locomotive modes