Off-Road Vehicle Recreation in the West: Implications of a Wyoming Analysis

Community/Rural/Urban Development, Resource /Energy Economics and Policy,

Modifications to the Aesop's Fable paradigm change New Caledonian crow performances

While humans are able to understand much about causality, it is unclear to what extent non-human animals can do the same. The Aesop's Fable paradigm requires an animal to drop stones into a water-filled tube to bring a floating food reward within reach. Rook, Eurasian jay, and New Caledonian crow performances are similar to those of children under seven years of age when solving this task. However, we know very little about the cognition underpinning these birds' performances. Here, we address several limitations of previous Aesop's Fable studies to gain insight into the causal cognition of New Caledonian crows. Our results provide the first evidence that any non-human animal can solve the U-tube task and can discriminate between water-filled tubes of different volumes. However, our results do not provide support for the hypothesis that these crows can infer the presence of a hidden causal mechanism. They also call into question previous object-discrimination performances. The methodologies outlined here should allow for more powerful comparisons between humans and other animal species and thus help us to determine which aspects of causal cognition are distinct to humans.Publisher PDFPeer reviewe

South Dakota Farmer-Based Reduced Till Crop Budgets

The use of reduced tillage practices in the U.S. has expanded a great deal over the past 15 years (USDA, 1986) . In 1985, roughly a quarter of South Dakota\u27s corn acreage was reported to be under reduced tillage (S25medra and Delvo, 1986) . A 1985 survey by South Dakota State University (SDSU) showed 69% of the farmer respondents to be using some type of reduced tillage on at least part of their acreage (Allen, 1987). Primary motivations for farmers adopting reduced tillage practices are to reduce machine costs, conserve moisture, and control soil erosion losses. Problems of weed control are usually accentuated under reduced tillage. Greater expenditures for chemical weed control are almost inevitable with reduced tillage. Some studies show interconnections between reduced tillage and fertilizer nutrient requirements

Evolution and Relationships of the Conifer Seed Cone Telemachus: Evidence from the Triassic of Antarctica

This is the publisher's version, also available electronically from http://www.jstor.org/stable/10.1086/651948The seed cone Telemachus is known from several Triassic localities in Gondwana. New specimens from two localities in Antarctica provide additional information about the type species, Telemachus elongatus, based on details of morphology and anatomy revealed by using a modified transfer technique on the compressed plants. Seed cones of T. elongatus are up to 6.0 cm long and characterized by conspicuous, elongate bracts. A second Antarctic species, described here as Telemachus antarcticus, is segregated, based on a shorter bract and differences in cone size. Newly recognized features of the genus include the shape, size, and disposition of the ovules; vascularization of the ovuliferous complex; and scale and bract histology. As a result of this new information, it is now possible to compare Telemachus with the permineralized Middle Triassic conifer seed cone Parasciadopitys from the Central Transantarctic Mountains. The similarities between the two genera make it possible to relate organs in different preservational modes and to develop a more complete concept for this widely distributed Gondwana conifer. Placing the Telemachus plant within a phylogenetic context makes it possible to evaluate the relationship with other so‐called transitional conifers, an informal group that has been interpreted as intermediate between Paleozoic and modern conifers

Feshbach Spectroscopy of a Shape Resonance

We present a new spectroscopy technique for studying cold-collision properties. The technique is based on the association and dissociation of ultracold molecules using a magnetically tunable Feshbach resonance. The energy and lifetime of a shape resonance are determined from a measurement of the dissociation rate. Additional spectroscopic information is obtained from the observation of a spatial interference pattern between an outgoing s wave and d wave. The experimental data agree well with the results from a new model, in which the dissociation process is connected to a scattering gedanken experiment, which is analyzed using a coupled-channels calculation.Comment: Introduction rewritte

Seasonality in Digestive-Gland Size and Metabolism in Relation to Reproduction in Haliotis kamtschatkana

A novel method of isolating digestive gland cells in abalone was used to provide information on the metabolic activity of this gland in Haliotis kamtschatkana. Activity, expressed as percent ·change in Vo2 of isolated cells before and after the addi­tion of glucose and amino acid substrates, was studied in relation to sex and to seasonal changes in gonad and digestive gland indices. At 3- to 4-mo intervals between May 1995 and July 1996, five collections of 10 adult abalone (equal sexes) were made from the West Coast of Vancouver Island, British Columbia. Each animal\u27s live mass (without shell) was recorded, and its gonad was aspirated from the digestive gland into a known volume (and mass) of seawater. The digestive gland was sliced free of its attachment, weighed, and related to shell-less body mass as percent digestive gland index (DGI). The gonad live mass was determined from the mass of aspirated mix of gonad and seawater, and related to shell-less body mass to give a percent gonad index (GI). Digestive gland cells were prepared and maintained in a special buffer, and their Vo2 \u27s measured in microrespirometers. There was no sex effect on seasonal DGI, but significant seasonal differences in DGls correlated perfectly with metabolic activity of digestive-gland cells with glucose substrate. Thus, when digestive glands were largest relative to body size, metabolic activity of their cells was greatest. Gls were significantly higher for males than females. There was a significant seasonal effect on Gls, with values being high in springtime be­ fore spawning (April to May, 10-11%) and low in winter (December, 6%), but with statistical overlap between these and sum­mer values (July to August, 7-8%). Metabolic response of the digestive gland cells was highest with glucose substrate (75% increase over presubstrate resting levels as compared with 4% for amino acid substrate), reflecting the carbohydrate-based metabolism of abalone

Shaped nozzles for cryogenic buffer gas beam sources

Cryogenic buffer gas beams are important sources of cold molecules. In this work we explore the use of a converging-diverging nozzle with a buffer-gas beam. We find that, under appropriate circumstances, the use of a nozzle can produce a beam with improved collimation, lower transverse temperatures, and higher fluxes per solid angle

Discriminating Stay-Green Grasses Using Hyperspectral Imaging and Chemometrics

Screening of plant collections for traits can be expensive, in terms of the number of plants to be screened, the duration of the plant lifecycle and the required observations. This study describes the application of a non-invasive method, hyperspectral imaging, combined with multivariate analysis, to distinguish between homozygous wild-type (YY) Lolium multiflorum and Lolium multiflorum F2 back cross plants heterozygous for y, a recessive Festuca pratensis stay-green gene (Thomas et al., 1997)

Dynamics of D1-brane in I-brane Background

This paper is devoted to the study of the effective field theory description of the probe D1-brane in the background of the system of two stacks of fivebranes in type IIB theory that intersect on $R^{1,1}$. We study the properties of the Dirac-Born-Infeld action for D1-brane moving in this background. We will argue that this action is invariant under an additional symmetry in the near horizon limit and that this new symmetry is closely related to the enhanced symmetry of the I-brane background considered recently in [hep-th/0508025]. We also solve explicitly the equation of motion of D1-brane in the near horizon limit.Comment: 21 pages, references adde