'Hurray for Mackenzie and Guilford for at last we have a pictorial guide to the rock-forming minerals! . . . such feasts of colour in mineralogy books are rare . . . an admirable guide'New Scientist
We report the first successful use of miniature Global Positioning System loggers to track the ocean‐going behaviour of a c. 400 g seabird, the Manx Shearwater Puffinus puffinus. Breeding birds were ...tracked over three field seasons during the incubation and chick‐rearing periods on their foraging excursions from the large colony on Skomer Island, Pembrokeshire, UK. Foraging effort was concentrated in the Irish Sea. Likely foraging areas were identified to the north, and more diffusely to the west of the colony. No foraging excursions were recorded significantly to the south of the colony, conflicting with the conclusions of earlier studies based on ringing recoveries and observations. We discuss several explanations including the hypothesis that foraging may have shifted substantially northwards in recent decades. We found no obvious relationship between birds’ positions and water depth, although there was a suggestion that observations at night were in shallower water than those during the day. We also found that, despite the fact that Shearwaters can be observed rafting off‐shore from their colonies in the hours prior to making landfall at night, breeding birds are usually located much further from the colony in the last 8 h before arrival, a finding that has significance for the likely effectiveness of marine protection areas if they are only local to the colony. Short sequences of precise second‐by‐second fixes showed that movement speeds were bimodal, corresponding to sitting on the water (most common at night and around midday) and flying (most common in the morning and evening), with flight behaviour separable into erratic (indicative of searching for food) and directional (indicative of travelling). We also provide a first direct measurement of mean flight speed during directional flight (c. 40 km/h), slower than a Shearwater's predicted maximum range velocity, suggesting that birds are exploiting wave or dynamic soaring during long‐distance travel.
Oil and gas are the main sources of energy in the United States. Part of their appeal is the high Energy Return on Energy Investment (EROI) when procuring them. We assessed data from the United ...States Bureau of the Census of Mineral Industries, the Energy Information Administration (EIA), the Oil and Gas Journal for the years 1919–2007 and from oil analyst Jean Laherrere to derive EROI for both finding and producing oil and gas. We found two general patterns in the relation of energy gains compared to energy costs: a gradual secular decrease in EROI and an inverse relation to drilling effort. EROI for finding oil and gas decreased exponentially from 1200:1 in 1919 to 5:1 in 2007. The EROI for production of the oil and gas industry was about 20:1 from 1919 to 1972, declined to about 8:1 in 1982 when peak drilling occurred, recovered to about 17:1 from 1986–2002 and declined sharply to about 11:1 in the mid to late 2000s. The slowly declining secular trend has been partly masked by changing effort: the lower the intensity of drilling, the higher the EROI compared to the secular trend. Fuel consumption within the oil and gas industry grew continuously from 1919 through the early 1980s, declined in the mid-1990s, and has increased recently, not surprisingly linked to the increased cost of finding and extracting oil.
•Younger AN/AI patients were interested in depression medications more than those 40 years of age and over.•AN/AI patients with more severe depression were more interested in lifestyle changes than ...those with mild depression.•Counseling and medications should be made more available earlier in the course of depression management.•Education on exercise, stress reduction, and healthy eating should be expanded in the primary care setting for AN/AI adults seeking care for depression.
Depression remains the second leading cause of disability worldwide. Symptoms of depression are expressed and experienced differently across cultural groups, impacting treatment decisions. Patient preferences predict service utilization, treatment selection and persistence, as well as health outcomes for medical and behavioral health conditions, including depression. We identified depression management preferences of Alaska Native and American Indian (AN/AI) people who receive care within a comprehensive, integrated, tribally owned and operated healthcare facility in Anchorage, Alaska.
Adult AN/AI patients who screened positive for depression (10 or greater on the Patient Health Questionnaire – 9 (PHQ-9)) completed a culturally-tailored decision-support tool to assess their depression management interests.
The 125 eligible patients, who screened positive for depression, preferred counseling and medications to peer support groups, herbal remedies, and spiritual support. Those 18–39 years of age were more likely to prefer medications and less likely to prefer spirituality and peer support than those 40 years of age and older. Patients with moderate and severe depression were more likely to prefer exercise, healthy eating, and stress reduction than individuals with mild depression.
Women comprised 78% of the sample. Responses may not adequately represent the views of men.
Counseling and medications should consistently be made available earlier in the course of depression management. Patient interest in exercise, stress reduction, and healthy eating to manage depression, especially among those with moderate and severe depression, offers opportunity for additional collaboration in an integrated care setting.
The homing ability of an intertidal fish, the shanny Lipophrys pholis, was investigated using two experiments that were based on the shanny’s natural propensity to home to a refuge. A displacement ...experiment demonstrated that the fish were able to accurately locate the previous position of a refuge once the shelter itself had been removed so that it could not be used as a cue to directly signal the goal location. This shows that the shanny can encode information about its familiar surroundings into a spatial map and use this information to home. A second experiment in which the cues internal and external to the experimental tank were put in conflict with one another suggested that the shanny can encode cues that are both intra‐ and external‐tank cues in its representation of space, but that there is individual variation in the type of cues that are used, or memorized.
Several studies have demonstrated female preference for elaborated secondary sexual characters in males. The idea that a well known product of discrimination training called peak-shift could also ...produce preferences for males with elaborated characteristics is discussed.
In a recent paper, Chua (1984) proposed a closed-form formula for calculating the duration of a bond. He effectively eliminated the summation signs from Macaulay's definition. The present analysis ...further simplifies the calculation of duration and suggests both a useful approximation and a unique interpretation. It is shown that duration can be written as a weighted average of 2 factors: 1. the present value interest factor of a one dollar annuity, and 2. the number of periods to maturity. The latter drops out of the equation when the bond is selling at par. The new equation is based on the Hicksian concept of duration as a measure of price sensitivity (risk). A numerical example is provided. It is also demonstrated that the present value interest factor of a one dollar annuity is a correct measure of elasticity for bonds selling at par and a good estimate of it for bonds selling close to par.
On the Linearity of Duration Babcock, Guilford C.
Financial analysts journal,
09/1986, Letnik:
42, Številka:
5
Journal Article
Recenzirano
It is demonstrated that the duration of every bond declines linearly between payment dates by an amount that exactly equals the time between such dates. Once the interest or coupon payment is ...received, duration rises abruptly to a recovery point that depends on the coupon, the yield, and the years to maturity of the individual bond. The duration of every bond follows the same downward path between payment dates, and every bond, except zero coupons, describes a sawtoothed pattern as its maturity shortens. This phenomenon is illustrated for the simple case of a 10-year bond with an annual coupon of $100. The time between payments is one year, and duration is shown to decrease by that amount in each and every year. The linear relation is both surprising and significant. The linearity stems from the fact that the compounding bond price is offset by a compounding interest payment. The relation is significant for the way in which the duration of fixed income portfolios is calculated and managed.
PDF
