Learning in the Repeated Secretary Problem

In the classical secretary problem, one attempts to find the maximum of an unknown and unlearnable distribution through sequential search. In many real-world searches, however, distributions are not entirely unknown and can be learned through experience. To investigate learning in such a repeated secretary problem we conduct a large-scale behavioral experiment in which people search repeatedly from fixed distributions. In contrast to prior investigations that find no evidence for learning in the classical scenario, in the repeated setting we observe substantial learning resulting in near-optimal stopping behavior. We conduct a Bayesian comparison of multiple behavioral models which shows that participants' behavior is best described by a class of threshold-based models that contains the theoretically optimal strategy. Fitting such a threshold-based model to data reveals players' estimated thresholds to be surprisingly close to the optimal thresholds after only a small number of games

Evidence for extended IR emission in NGC2798 and NGC6240

Extended emission at 10 and 20 microns can be used to distinguish starbursts from monsters as the underlying energy source driving the luminous infrared emission in the central regions of galaxies. The spatial extent of the mid infrared emission in the interacting galaxy NCG 2798 and the merger NGC 6240 were investigated. The 10 and 20 micron profiles of the IR source in NGC 2798 are significantly wider than beam profiles measured on a standard star, supporting a starburst interpretation of its IR luminosity. For NGC 6240 there is marginal evidence for an extended 10 micron source, suggesting that a significant fraction of its IR luminosity could be produced by a burst of star formation

Effect of Wave Action on Movement in the Owl Limpet, \u3cem\u3eLottia gigantea\u3c/em\u3e, in Santa Cruz, California

The critical role of wave energy in the ecology of nearshore organisms is widely accepted, based primarily on biotic correlations over large scales of time and space. Much less is known about how large waves impact the behavioral ecology of individual organisms. Theoretical considerations and measurements of tenacity predict that intertidal gastropods should minimize the chances of dislodgement during periods of high waves by remaining stationary. We tested this prediction by observing a population of the owl limpet, Lottia gigantea G. B. Sowerby I, 1834, in a range of sea conditions. We found the proportion of the population moving during high tide was reduced when maximum wave height exceeded 1 m. This relatively low threshold suggests that ambient sea state has a consistent influence on foraging strategy of intertidal limpets

Objective measurement of cough frequency during COPD exacerbation convalescence

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide. Cough and sputum production are associated with adverse outcomes in COPD and are common during COPD exacerbation (AE-COPD). This study of objective cough monitoring using the Hull Automated Cough Counter and Leicester Cough Monitor software confirms that this system has the ability to detect a significant decrease in cough frequency during AE-COPD convalescence. The ability to detect clinically meaningful change indicates a potential role in home monitoring of COPD patients

Infrared images of merging galaxies

Infrared imaging of interacting galaxies is especially interesting because their optical appearance is often so chaotic due to extinction by dust and emission from star formation regions, that it is impossible to locate the nuclei or determine the true stellar distribution. However, at near-infrared wavelengths extinction is considerably reduced, and most of the flux from galaxies originates from red giant stars that comprise the dominant stellar component by mass. Thus near infrared images offer the opportunity to study directly components of galactic structure which are otherwise inaccessible. Such images may ultimately provide the framework in which to understand the activity taking place in many of the mergers with high Infrared Astronomy Satellite (IRAS) luminosities. Infrared images have been useful in identifying double structures in the nuclei of interacting galaxies which have not even been hinted at by optical observations. A striking example of this is given by the K images of Arp 220. Graham et al. (1990) have used high resolution imaging to show that it has a double nucleus coincident with the radio sources in the middle of the dust lane. The results suggest that caution should be applied in the identification of optical bright spots as multiple nuclei in the absence of other evidence. They also illustrate the advantages of using infrared imaging to study the underlying structure in merging galaxies. The authors have begun a program to take near infrared images of galaxies which are believed to be mergers of disk galaxies because they have tidal tails and filaments. In many of these the merger is thought to have induced exceptionally luminous infrared emission (cf. Joseph and Wright 1985, Sanders et al. 1988). Although the optical images of the galaxies show spectacular dust lanes and filaments, the K images all have a very smooth distribution of light with an apparently single nucleus

Anagrus spp. (Hymenoptera: Mymaridae) reared from plants collected during winter in south central Washington and north central Oregon

Anagrus daanei S. Triapitsyn, A. erythroneurae S. Trjapitzin and Chiappini, and A. frettakovae S. Triapitsyn parasitize Western grape leafllopper, Erythroneura elegantula Osborn, and Virginia creeper leafhopper, E. ziczac Walsh, eggs during the summer. These leafhoppers overwinter as adults and Anagrus overwinter in leafhopper eggs. Thus, Anagrus must find other leafhopper eggs in which to overwinter. To identify plants on which these parasitoids and their host eggs overwinter, we collected 31 species of plants from 52 sites in the grape growing region of south central Washington and north central Oregon during the winter from 2000 to 2007. A total of 733 female and 1066 male Anagrus was reared from the plants. Twelve plant species harboured Anagrus spp. during the winter. Anagrus erythroneurae was reared from blackberry, Rubus armeniacus Focke; willow, Salix spp.; Wood’s rose, Rosa woodsii Lindley; sweetbrier rose, R. eglanteria L.; rugose rose, R. rugosa Thunberg; and ornamental roses, Rosa spp. L. Anagrus tretiakovae was found on choke cherry, Prunus virginiana L.; rugose rose; Rosa spp.; and blackberry. Only one specimen, from omamental rose, was tentatively identified as A. daanei. Other specimens were identified as A. atomus L., A. avalae Soyka, A. nr. sp. avalae, A. nr. sp. columbi Perkins, A. nigriventris Girault, and A. nr. sp. nigriventris

Treatment for unicameral bone cysts in long bones: an evidence based review

The purpose of this paper is to perform an evidence based review for treatment of unicameral bone cysts. A search of MEDLINE (1966 to 2009) was conducted and the studies were classified according to levels of evidence. This review includes only comparative Level I-III studies. The systematic review identified 16 studies. There is one level I study, one level II study and the remaining 14 studies are level III. Seven of the sixteen studies had statistically different results: three studies indicated that steroid injection was superior to bone marrow injection or curettage and bone grafting; one study indicated that cannulated screws were superior to steroid injections; one study indicated resection and myoplasty was superior to steroid injection; one study indicated a combination of steroid, demineralized bone matrix and bone marrow aspirate, and curettage and bone grafting were superior to steroid injection; and one study indicated that curettage and bone grafting was superior to non-operative immobilization. Based on one Level I study, including a limited number of individuals, steroid injection seems to be superior to bone marrow injection. As steroid injections have already demonstrated superiority over bone marrow injections in a randomized clinical trial, the next step would be a prospective trial comparing steroid injections with other treatments

USCID fourth international conference

Presented at the Role of irrigation and drainage in a sustainable future: USCID fourth international conference on irrigation and drainage on October 3-6, 2007 in Sacramento, California.Includes bibliographical references.Evapotranspiration and net irrigation water requirements were determined for 123 weather station locations across the state of Idaho for available periods of record. Estimates were made for daily, monthly and annual timesteps. Updated methods were employed for calculating reference evapotranspiration (ETr) and crop coefficients (Kc). The ET estimates cover a wide range of agricultural crops grown in Idaho and, in addition, ET estimates have been made for a number of native plant systems including wetlands, rangeland, and riparian trees. Estimates have been made for evaporation from three types of open water surfaces ranging from deep reservoirs to small farm ponds. The ET and net irrigation water requirement calculations are intended for use in design and management of irrigation systems, for water rights management and consumptive water rights transfers and for hydrologic studies. ET calculations have been made for all times during the calendar year including winter to provide design and operation information for managing land application of agriculture, food processing and other waste streams. The weather stations evaluated include 107 National Weather Service (NWS) cooperative stations measuring primarily air temperature and precipitation and 16 AgriMet agricultural weather stations. The AgriMet stations measure a full complement of weather data affecting evapotranspiration and are located primarily in the southern part of the state. Estimates at many stations cover more than 80 to 100 year periods of air temperature data. Because only maximum and minimum air temperature are observed at the NWS cooperative stations, the solar radiation, humidity and wind speed data parameters required in the ASCE Penman-Monteith equation (ASCE-PM) were estimated similar to recommendations in ASCE-EWRI (2005) where estimates for solar radiation (Rs) were based on differences between daily maximum and minimum air temperature and estimates for daily dewpoint temperature were based on daily minimum air temperature. Estimates for wind speed were based on long-term mean monthly summaries from AgriMet stations in southern Idaho and some airport locations in central and northern Idaho. Crop evapotranspiration, abbreviated ETc, was calculated on a daily timestep basis for improved accuracy. Daily calculation timesteps allowed for the calculation of evaporation of water from wet soil surfaces following precipitation or irrigation events. ETc for monthly, growing season and annual periods were summed from the daily calculations. Basal crop coefficient curves were developed or organized for 42 crop and land-cover types. Scheduling of irrigations was simulated to estimate soil evaporation from irrigation wetting events using a root-zone water balance