Some Movements of Black-Tailed Jackrabbits in Northern Utah

This work describes the extent and pattern of some black-tailed jackrabbit (Lapus californicus) movements and areas of activity in northern Utah and their relationship to sex and age, and season of the year. Black-tailed jackrabbits are the most common lagomorphs in much of the western United States, particularly in that vegetational association descibed by McDougal (1908) as the sagebrush desert. Furthermore, Adams and Adams (1959) have suggested a correlation between sagebrush (Artemisia tridentata) incidence and jackrabbit density. Farmers often regard this species as a liability because of its depredations on alfalfa (Medicago sativa), crested wheatgrass (Agropyron cristatum) and cultivated crops (Lewis, 1946). Ranchers claim that hares compete with grazing stock and Vorhies and Taylor (1933) found such competition in Arizona. On the other hand, jackrabbit hunting provides year-round sport in many western states. If control or management of this species is necessary, movement information is essential, for Leopold (1933) stated: Mobility of a species determines the minimum unit of management. Censuses and density indices are the yardsticks of success in game management. Movement is a determinant of density, and movement data provide insight into phenomena of population dynamics as well as management information

OAM mode selection for high-speed optical communications : a bit loading approach

Occupying more channels increases transmission rate, however, crosstalk increases to an unacceptable level long before all 24 channels can be exploited. The crosstalk is not uniform between modes, hence occupying different subsets of channels leads to vastly different achievable transmission capacities. In addition to optimizing occupied subsets of channels, we adopt a bit loading approach. We examine several resource allocation strategies in a coherent detection system, starting with typical OAM mode group granularity (all channels in a group occupied) and ending with single channel granularity. By exhaustive search at mode group granularity, we find a bit load increasing the total capacity by ∼15% compared to a minimax solution for mode group allocation. Single channel granularity imposes great computational effort to optimize bit loading. We propose search algorithms that are computationally tractable and improve capacity by ∼30% vis-àvis the minimax solution for mode groups. Finally, we examine the impact of signal-to-noise ratio (SNR) and receiver digital signal processing (DSP) complexity on the overall capacity. We include a discussion of DSP with limited or with no multi-input, multioutput (MIMO) processing.Our algorithms could be applied to any mode multiplexing fiber, as it only relies on knowledge of the crosstalk matrix across modes

Habitat and Weather Effects on Northern Bobwhite Brood Movements

We observed radio-marked northern bobwhite (Colinus virginianus) broods (adults with chicks :S21 days old; n = 12) in Kansas during 1991-94 to test effects of weather (temperature and precipitation) and macrohabitat (composition, relative diversity, and mean distance to grassland) variables on brood home range size and daily movements at large (28.5 km2), intermediate (3.14 km2), and small (about 0.14 km2) spatial scales surrounding habitats available for broods. Principal component analyses followed by stepwise multiple linear regression indicated neither weather nor habitat influenced (P 2: 0.1) home range size at the large and intermediate scales. However, the principal component representing mean distance to grassland and percent cropland within the home range (i.e., at a small scale) was positively related to home range size. Neither temperature nor habitat influenced daily distance of movements. We concluded that brood mobility was independent of landscape-scale features, but that habitat management at smaller spatial scales could influence movements. To create optimal habitat for bobwhite, managers should consider relationships among habitat attributes and the movement of individuals, including the spatial scales at which these relationships are most important

The motivating operation and negatively reinforced problem behavior. A systematic review.

The concept of motivational operations exerts an increasing influence on the understanding and assessment of problem behavior in people with intellectual and developmental disability. In this systematic review of 59 methodologically robust studies of the influence of motivational operations in negative reinforcement paradigms in this population, we identify themes related to situational and biological variables that have implications for assessment, intervention, and further research. There is now good evidence that motivational operations of differing origins influence negatively reinforced problem behavior, and that these might be subject to manipulation to facilitate favorable outcomes. There is also good evidence that some biological variables warrant consideration in assessment procedures as they predispose the person's behavior to be influenced by specific motivational operations. The implications for assessment and intervention are made explicit with reference to variables that are open to manipulation or that require further research and conceptualization within causal models