Linear Approximations and Tests of Conditional Pricing Models

We construct a simple reduced-form example of a conditional pricing model with modest intrinsic nonlinearity. The theoretical magnitude of the pricing errors (alphas) induced by the application of standard linear conditioning are derived as a direct consequence of an omitted variables bias. When the model is calibrated to either characteristics sorted or industry portfolios, we find that the alphas generated by approximation-induced specification error are economically large. A Monte Carlo analysis shows that finite-sample alphas are even larger. It also shows that the power to detect omitted nonlinear factors through tests based on estimated risk premiums can sometimes be quite low, even when the effect of misspecification on alphas is large.

Sandhill Crane Roost Selection, Human Disturbance, and Forage Resources

Sites used for roosting represent a key habitat requirement for many species of birds because availability and quality of roost sites can influence individual fitness. Birds select roost sites based on numerous factors, requirements, and motivations, and selection of roosts can be dynamic in time and space because of various ecological and environmental influences. For sandhill cranes (Antigone canadensis) at their main spring staging area along the Platte River in south-central Nebraska, USA, past investigations of roosting cranes focuse donphysical channel characteristics related to perceived security as motivating roost distribution.We used 6,310 roost sites selected by 313 sandhill cranes over 5 spring migration seasons (2003–2007) to quantify resource selection functions of roost sites on the central Platte River using a discrete choice analysis. Sandhill cranes generally showed stronger selection for wider channels with shorter bank vegetation situated farther from potential human disturbance features such as roads, bridges, and dwellings.Furthermore, selection for roost sites with preferable physical characteristics (wide channels with short bank vegetation) was more resilient to nearby disturbance features than more narrow channels with taller bank vegetation. The amount of cornfields surrounding sandhill crane roost sites positively influenced relative probability of use but only for more narrow channels \u3c100m and those with shorter bank vegetation. We confirmed key resource features that sandhill cranes selected at river channels along the Platte River, and after incorporating spatial variation due to human disturbance, our understanding of roost site selection was more robust, providing insights on how disturbance may interact with physical habitat features. Managers can use information on roost-site selection when developing plans to increase probability of crane use at existing roost sites and to identify new areas for potential use if existing sites become limited

USE OF SATELLITE TELEMETRY TO IDENTIFY TEMPORAL AND SPATIAL DISTRIBUTION OF THE MIDCONTINENT SANDHILL CRANE POPULATION THROUGHOUT THE ANNUAL CYCLE

Effective management of the midcontinent sandhill crane (Grus canadensis) population requires having detailed information available on the distribution of subspecies and subpopulations throughout the annual cycle. The current study is being undertaken in partnership with several federal and state agencies and private organizations to obtain key information not currently available. We are monitoring crane movements throughout the year by attaching Platform Transmitting Terminals (PTTs) to plastic leg bands and with the aid of equipment on board orbiting NOAA weather satellites relocating the radiomarked individuals at 4-10 day intervals throughout the year. Twenty-one cranes were captured and radio-marked in the Central Platte River Valley in early spring 1998 and 1999. Results to date indicate the technique is well suited for obtaining the types of information being sought. Most of the radio-marked cranes after departing from the Platte River in spring staged again at sites in southern Saskatchewan but those of the Canadian subspecies (G. c. rowan i) breeding in Manitoba and Ontario staged in northwestern Minnesota. Distnbution of radio-marked individuals on the breeding grounds suggests that northeastern Russia may be a more important breeding area for lesser sandhill cranes (G. c. canadensis) than previously thought; 50% of lesser sandhill cranes tagged to date (6 of 12) migrated to locations in northeastern Siberia. Onset offall migration occurred from mid-August to mid-September depending on latitude; fall staging was centered primarily in 3 areas of southern Saskatchewan with fewer radio-marked cranes staging in southwestern Manitoba and central North Dakota. Most radio-marked cranes have spent winter in west Texas, 2 (both G. c. rowani) have occupied sites near the Texas Gulf Coast, and 1 each spent winter at sites in Arizona and New Mexico (both G. c. canadensis breeding in northeastern Siberia). Habitats occupied by cranes are being identified throughout the annual cycle with the aid of GIS methodology as are temporal and spatial patterns of use of the Central Platte River Valley. Information obtained from the study will be used to delineate breeding ranges, migration corridors, staging areas, and wintering grounds of subspecies and subpopulations to allow crane managers to better meet the needs of the midcontinent population. Current plans are to gather information on a total of 200 sandhill cranes over the study period with 42 cranes to be radio marked in 2000. Those interested in following the radio-marked cranes during their annual cycle or learning more about the crane study can do so by logging on our web site at www.npwrc.usgs.gov/perm/cranemov/cranmov.htm

THE IMPACT OF MARKING ON CRANES: AN ISSUE PAPER

As crane researchers and conservationists, our overarching objective is to learn and gather information about our study subjects while doing as little harm as possible. New technologies may be emerging too rapidly for researchers to assess the effectiveness or potential adverse effects of the devices, despite the ease and increasing accuracy of the information they provide. Researchers need to be able to gather information to answer various questions in a way that balances ethics and expense. With marking of cranes as a focal point, we discuss issues surrounding crane research based on various techniques, some health issues that are a direct result of marking cranes, and consultation with telemetry companies to improve design of devices to be deployed on cranes. We submit a Call to Action: create a global crane research working group under the oversight of the International Union for Conservation of Nature (IUCN) Crane Specialist Group (CSG), a group dedicated to promoting the study and conservation of the world’s 15 crane species

Mortality in Aransas-Wood Buffalo Whooping Cranes: Timing, Location, and Causes

The Aransas-Wood Buffalo Population (AWBP) of Whooping Cranes (Grus americana) has experienced a population growth rate of approximately 4% for multiple decades (Butler et al., 2014a; Miller et al., 1974). Population growth for long-lived species of birds is generally highly sensitive to variation in adult mortality rates (Sæther and Bakke, 2000). A population model for endangered Red-crowned Cranes (Grus japonensis) in Japan conforms to this pattern, where growth rate is most sensitive to adult mortality (Masatomi et al., 2007). Earlier analyses observed that the AWBP growth rate increased in the mid-1950s and that this increase was likely caused by reduced annual mortality rates, even while the population experienced slightly decreasing natality (Binkley and Miller, 1988; Miller et al., 1974). A more contemporary analysis of the AWBP determined that approximately 50% of variation in annual population growth could be explained by variation in annual mortality (Butler et al., 2014a). Therefore, as a vital rate, mortality is critical to the maintained growth of the AWBP

Mortality in Aransas-Wood Buffalo Whooping Cranes: Timing, Location, and Causes

The Aransas-Wood Buffalo Population (AWBP) of Whooping Cranes (Grus americana) has experienced a population growth rate of approximately 4% for multiple decades (Butler et al., 2014a; Miller et al., 1974). Population growth for long-lived species of birds is generally highly sensitive to variation in adult mortality rates (Sæther and Bakke, 2000). A population model for endangered Red-crowned Cranes (Grus japonensis) in Japan conforms to this pattern, where growth rate is most sensitive to adult mortality (Masatomi et al., 2007). Earlier analyses observed that the AWBP growth rate increased in the mid-1950s and that this increase was likely caused by reduced annual mortality rates, even while the population experienced slightly decreasing natality (Binkley and Miller, 1988; Miller et al., 1974). A more contemporary analysis of the AWBP determined that approximately 50% of variation in annual population growth could be explained by variation in annual mortality (Butler et al., 2014a). Therefore, as a vital rate, mortality is critical to the maintained growth of the AWBP

Everolimus dosing recommendations for tuberous sclerosis complex–associated refractory seizures

ObjectiveThe present analysis examined the exposure-response relationship by means of the predose everolimus concentration (C-min) and the seizure response in patients with tuberous sclerosis complex-associated seizures in the EXIST-3 study. Recommendations have been made for the target C-min range of everolimus for therapeutic drug monitoring (TDM) and the doses necessary to achieve this target C-min

Mortality in Aransas-Wood Buffalo Whooping Cranes: Timing, Location, and Causes

The Aransas-Wood Buffalo Population (AWBP) of Whooping Cranes (Grus americana) has experienced a population growth rate of approximately 4% for multiple decades (Butler et al., 2014a; Miller et al., 1974). Population growth for long-lived species of birds is generally highly sensitive to variation in adult mortality rates (Sæther and Bakke, 2000). A population model for endangered Red-crowned Cranes (Grus japonensis) in Japan conforms to this pattern, where growth rate is most sensitive to adult mortality (Masatomi et al., 2007). Earlier analyses observed that the AWBP growth rate increased in the mid-1950s and that this increase was likely caused by reduced annual mortality rates, even while the population experienced slightly decreasing natality (Binkley and Miller, 1988; Miller et al., 1974). A more contemporary analysis of the AWBP determined that approximately 50% of variation in annual population growth could be explained by variation in annual mortality (Butler et al., 2014a). Therefore, as a vital rate, mortality is critical to the maintained growth of the AWBP

Interstitials, Vacancies, and Supersolid Order in Vortex Crystals

Interstitials and vacancies in the Abrikosov phase of clean Type II superconductors are line imperfections, which cannot extend across macroscopic equilibrated samples at low temperatures. We argue that the entropy associated with line wandering nevertheless can cause these defects to proliferate at a sharp transition which will exist if this occurs below the temperature at which the crystal actually melts. Vortices are both entangled and crystalline in the resulting ``supersolid'' phase, which in a dual ``boson'' analog system is closely related to a two-dimensional quantum crystal of He$^4$ with interstitials or vacancies in its ground state. The supersolid {\it must} occur for $B\gg B_\times$, where $B_\times$ is the decoupling field above which vortices begin to behave two-dimensionally. Numerical calculations show that interstitials, rather than vacancies, are the preferred defect for $B\gg \phi_0/\lambda_\perp^2$, and allow us to estimate whether proliferation also occurs for B\,\lot\,B_\times.The implications of the supersolid phase for transport measurements, dislocation configurations and neutron diffraction are discussed.Comment: 53 pages and 15 figures, available upon request, written in plain TE