Growth and mortality of Ozark bass (Ambloplites constellatus) in streams of the Ozark Highlands

The Ozark bass (Ambloplites constellatus) is endemic to the Upper White River Basin, and a limited amount of information exists on the Ozark bass population, including growth and mortality characteristics. The purpose of this study was to determine growth and mortality of Ozark bass in the Upper White River Basin, compare growth of Ozark bass to other Ambloplites species, and compare growth and mortality of Ozark bass between sample sites. Sampling occurred in Crooked Creek and in the Lower Wilderness Area (LWA) of the Buffalo River, with multiple collections from each body of water. Sampling occurred during summer 2013 via electroshocking from a boat. Length and weight data were recorded while sampling, and fish ages were determined through otolith retrieval. Ozark bass exhibited similar growth patterns to Shadow bass (Ambloplites ariommus); however, Rock bass (Ambloplites rupestris) grew faster and larger. Growth of Ozark bass appeared to be similar between Crooked Creek and the LWA of the Buffalo River until 5 years of age. After age 5, the growth of fish collected from the LWA of the Buffalo River slowed compared to 5 and older fish collected from Crooked Creek. Ozark bass of the LWA of the Buffalo River had an overall greater mortality rate than those in Crooked Creek; however, one of two sites sampled on Crooked Creek had a comparable fish mortality rate to that measured in the LWA of the Buffalo River. Results indicated that size-selected mortality may have occurred in the LWA of the Buffalo River and at least one location sampled in Crooked Creek, possibly due to fishing mortality and angler popularity at the sites. Data collected in this study were part of a long-term attempt by the Arkansas Game and Fish Commission to gather baseline data on the Ozark bass population and to determine the efficacy of current harvest regulations for that species in the Upper White River Basin. Baseline data will be used in the future to determine whether local fish populations respond to climate change or other impacts to the watershed

Martian dust threshold measurements: Simulations under heated surface conditions

Diurnal changes in solar radiation on Mars set up a cycle of cooling and heating of the planetary boundary layer, this effect strongly influences the wind field. The stratification of the air layer is stable in early morning since the ground is cooler than the air above it. When the ground is heated and becomes warmer than the air its heat is transferred to the air above it. The heated parcels of air near the surface will, in effect, increase the near surface wind speed or increase the aeolian surface stress the wind has upon the surface when compared to an unheated or cooled surface. This means that for the same wind speed at a fixed height above the surface, ground-level shear stress will be greater for the heated surface than an unheated surface. Thus, it is possible to obtain saltation threshold conditions at lower mean wind speeds when the surface is heated. Even though the mean wind speed is less when the surface is heated, the surface shear stress required to initiate particle movement remains the same in both cases. To investigate this phenomenon, low-density surface dust aeolian threshold measurements have been made in the MARSWIT wind tunnel located at NASA Ames Research Center, Moffett Field, California. The first series of tests examined threshold values of the 100 micron sand material. At 13 mb surface pressure the unheated surface had a threshold friction speed of 2.93 m/s (and approximately corresponded to a velocity of 41.4 m/s at a height of 1 meter) while the heated surface equivalent bulk Richardson number of -0.02, yielded a threshold friction speed of 2.67 m/s (and approximately corresponded to a velocity of 38.0 m/s at a height of 1 meter). This change represents an 8.8 percent decrease in threshold conditions for the heated case. The values of velocities are well within the threshold range as observed by Arvidson et al., 1983. As the surface was heated the threshold decreased. At a value of bulk Richardson number equal to -0.02 the threshold friction speed and threshold wind speed appears to level-off to a constant value. This trend also was observed in the MARSWIT experiments involving the 11 micron sized-silt material

A 3-component laser-Doppler velocimeter data acquisition and reduction system

A laser doppler velocimeter capable of measuring all three components of velocity simultaneously in low-speed flows is described. All the mean velocities, Reynolds stresses, and higher-order products can be evaluated. The approach followed is to split one of the two colors used in a 2-D system, thus creating a third set of beams which is then focused in the flow from an off-axis direction. The third velocity component is computed from the known geometry of the system. The laser optical hardware and the data acquisition electronics are described in detail. In addition, full operating procedures and listings of the software (written in BASIC and ASSEMBLY languages) are also included. Some typical measurements obtained with this system in a vortex/mixing layer interaction are presented and compared directly to those obtained with a cross-wire system

Ancient Andean Headgear: Medium and Measure of Cultural Identity

From the earliest recorded periods of southern Andean history, distinctive clothing styles have served to identity specific socio-cultural groups and provide clues about cultural origins. Unique environmental conditions, especially present along the arid Pacific coast of South America, have allowed the preservation of a vast archive of usually perishable material. From the far south coast of Peru to the northern desert regions of Chile, textiles, and especially headgear forms were worn to distinguish between the diverse populations who established permanent settlements along the narrow river valleys linking highland regions and the coast. The south central Andes region has always known a considerable amount of cultural contact, and a similar widespread textile tradition developed within the area. In most archaeological collections, warp-faced woven camelid-fiber cloth predominates, created with 2-ply yarns first spun in the Z direction and plied S. It is generally assumed that during many periods highland cultures based around Lake Titicaca exerted considerable influence upon the coast, and this basic woven tradition may have originated there. However, the criteria used to identify highland and coastal traits remains elusive. Textiles, the artifacts most useful in discussing cultural and ethnic identity, are preserved only along the coast. Perishable materials are rarely found in highland contexts, where seasonal rains destroy organic artifacts. The most easily recognized highland traits are those found in designs which imitate images carved on highland stone sculptures or painted on ceramics. However, most textile remains are simple, unpatterned fabrics. Within archaeological collections, we must identify traits, other than design, which might be site- or region-specific, and which might suggest borrowing between regions, or blending of cultural groups; traits such as form, fiber, and structure. In an attempt to read the message of cultural identity with the medium of archaeological textiles, we present data from collections excavated in two separate river valleys, representing two distinct periods in Andean cultural history. Evidence of an early coastal-related culture (dated 800 BC–AD 100) has been found at the Caserones site in the Tarapaca Valley of northern Chile, while the late prehistoric Estuquina site in the Moquegua Valley of far southern Peru (dated AD 1100–1450) is a small, locally adapted, mid-valley village with basic highland attributes. To illuminate the specific ways in which pre-conquest Andeans presented themselves to others, we have chosen to examine headgear, or gorros, a traditional male Andean accessory and an object especially sensitive to ethnic identity

Physics of windblown particles

A laboratory facility proposed for the Space Station to investigate fundamental aspects of windblown particles is described. The experiments would take advantage of the environment afforded in earth orbit and would be an extension of research currently being conducted on the geology and physics of windblown sediments on earth, Mars, and Venus. Aeolian (wind) processes are reviewed in the planetary context, the scientific rational is given for specific experiments to be conducted, the experiment apparatus (the Carousel Wind Tunnel, or CWT) is described, and a plan presented for implementing the proposed research program

The Use of 2,4-Dinitrophenylhydrazine Derivatives of Ovarian Ketosteroids in Steroid Analysis

This paper reports the development of a technically simple analytical technique for the characterization and quantitative determination of ovarian ketosteroids employing derivative formation with 2,4-dinitrophenylhydrazine (2,4-DNP), separation by thin-layer chromatography (TLC), and quantitative determination by spectrophotometry. The chemical identities of the derivatives were established by nitrogen analysis. The melting point, chromatographic mobilities of the free steroids and their derivatives on silica gel G in three systems, wavelength of maximum absorption in chloroform and ethanol, and molar absorption coefficient are reported for the 2,4-DNP derivatives of ovarian ketosteroids. The relationship between the absorption maximum in chloroform and the chemical structure of the derivatives has been analyzed

Assessment of the plume theory predictions of crown scorch using transport models

The aim of our work is to study numerically crown scorch as the effectsof a fire line spreading through surface fuel under a tree canopy. Theobjective was to assess the usual assumptions made when one uses the Van Wagner criteria, which are indeed simple predictive models for crown scorch height, to estimate crown scorch. For this purpose the FIRESTAR 2D and FIRETEC wildfire simulators are used. We simulated the fire line by a heat source at ground level and mainly investigated the temperature field. As a first step, we ran computations of thermal plumes with no-wind and with no canopy, for first comparison to plume theory. The influence of crown existence on the temperature field above the heat source, as well as on crown scorch, was then investigated. As a second step, the effect of a wind to the plume, as well as to crown scorch, was shown for the no-canopy and canopy cases

Geographic variation in dispersal distance facilitates range expansion of a lake shore plant in response to climate change

AimGeographic variation in dispersal abilities is widespread and likely to affect species’ range dynamics in response to climate change. However, distribution models that predict climate‐induced range shifts do not account for spatial variation in dispersal. We developed an eco‐genetic model to investigate how variation in dispersal distances across a species’ range could interact with climate‐induced selection and alter predicted range dynamics in a species with documented variation in dispersal traits.LocationWe investigated the range of an annual plant, Cakile edentula var. lacustris, which occupies beaches spanning a 555 km latitudinal gradient along the Laurentian Great Lakes.MethodsWe built a hybrid model that combines climatic niche modelling, based on decadal climate projections, with an individual‐based model that allows for evolutionary processes to act upon a heritable dispersal kernel. We evaluated how spatial variation in dispersal distance and dispersal evolution influenced range dynamics, spatial and temporal variation in dispersal, and the distribution of neutral genetic variation. The model was parametrized with data on C. edentula’s distribution, life history and dispersal characteristics.ResultsGeographic variation in dispersal distance, adaptive dispersal evolution and dispersal distance increased the potential for local populations of C. edentula to keep pace with changing climatic conditions through range shifts. Dispersal distances always increased at the expanding and contracting range edges when dispersal was allowed to evolve. Furthermore, scenarios where dispersal distances were initially lower at the range edges resulted in the largest evolutionary changes over 105 years (>1.5 km increase in mean distance at northern edge). Adaptive dispersal evolution always reduced neutral genetic diversity across the species’ range.Main conclusionsVariation in dispersal abilities across C. edentula’s range and adaptive evolution led to different predicted outcomes in range dynamics during climate change illustrating the importance of including spatial variation in dispersal into species distribution models.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151269/1/ddi12951.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151269/2/ddi12951_am.pd

Velvet Longhorned Beetle (Trichoferus campestris (Faldermann)

The velvet longhorned beetle is an invasive wood-boring pest that is native to Asia and Russia. It infests fruit, forest, and ornamental trees, as well as green and dry wood, such as timber and lumber. This fact sheet provides a description, and information on life history, plant hosts, injury symptoms, monitoring, and management