Spatial Synchrony of Monarch Butterflies

I examined spatial synchrony in Populations of monarch butterflies (Danaus plexippus) during the summer breeding season across North America and while overwintering along the Pacific Coast. Spatial synchrony was observed in all analyses, but was particularly great among eastern summer populations and among overwintering populations on the Pacific Coast. Thus, in a year when relatively large numbers of monarchs were found at a particular breeding or wintering site in these populations, other sites within a wide area were likely to have relatively large numbers of monarchs as well. Spatial structure, measured by the decline in synchrony with distance, was relatively strong among summer populations in eastern North America, weaker, but present, among western Summering populations and virtually nonexistent among overwintering populations along the Pacific Coast. Spatial synchrony in mean temperatures during the relevant time periods was generally much greater than that observed in the monarchs, consistent with the hypothesis that environmental factors (the Moran effect) may be playing a central role in causing the observed population sync,irony. However, differences in spatial structure between monarch populations and mean temperature during the summer suggest that other factors, possibly post-migratory dispersal, are also affecting synchrony. Dispersal is particularly likely to be important in determining the amusual lack of spatial Structure observed in overwintering populations of monarchs, which are believed to mix over wide areas during fall migration

A circularly polarized corner reflector antenna

Image theory is used to develop the far field and polarization equations for a ninety degree corner reflector antenna. These equations are in terms of spherical coordinates, the length of the dipole element, the distance of the dipole from the corner of the reflector, and the angle of tilt of the dipole element with the apex of the corner. The equations are simplified to give the far fields in the vertical and horizontal planes for the special case of a half-wavelength dipole. An expression to calculate the distance of the dipole from the corner necessary to give circular polarization broadside to the antenna in terms of the tilt angle of the dipole is derived. This distance is plotted against the tilt angle. Plots are made of the far field in the vertical and horizontal planes for various values of distance and tilt angle, maintaining circular polarizations broadside --Abstract, page ii

The Jewish Festivals Mentioned in the New Testament

As far as the life of the New Testament believer is concerned, the ancient festivals of the Jews are null and void. All Old Testament rites and ceremonies, which were only a shadow of things to come” (Col. 2,16), have been abrogated by the coming of God\u27s Son into the flesh. But even though the Jewish festivals are no longer to be observed by us, we cannot afford to forget all about them. Leaving the Old Testament out of the question altogether, the proper understanding of the New Testament alone demands a thorough investigation of all that is connected with those old festivals. It is impossible, for example, to view the life of Christ correctly without having as background the knowledge of Jewish religious life in His time. The subject of this thesis, therefore, is well worthy of consideration

Brief Studies

Luther As a Student of Hebre

Multiport synthesis with multi-layered distributed parameter RC networks

Synthesis and design techniques for multiport, multilayered, distributed parameter RC networks are investigated in this dissertation. The basic building block is a network section of uniform width consisting of alternate layers of resistive and dielectric materials on top of a perfectly conducting plane. The resulting network is composed of a cascade of these sections with all access terminals at one end of the cascaded network. The terminals at the other end are either open circuited or short circuited. A method is discussed for synthesizing a network from a prescribed network admittance matrix. An approximation technique is given for obtaining a realizable network immittance matrix from Bode plots of the short circuit admittance parameters for the four-layered case. Since this approximation technique may be difficult to implement in practical engineering problems, high and low frequency asymptotic relationships are given which are useful in practical design of networks. Design suggestions are given for notch, low pass, and high pass networks --Abstract, page ii

New Mexico Daily Lobo, Volume 088, No 131, 4/9/1984

New Mexico Daily Lobo, Volume 088, No 131, 4/9/1984https://digitalrepository.unm.edu/daily_lobo_1984/1056/thumbnail.jp

Temporal Variability and cooperative Breeding: Testing the Bet-Hedging Hypothesis in the Acorn Woodpecker

Cooperative breeding is generally considered an adaptation to ecological constraints on dispersal and independent breeding, usually due to limited breeding opportunities. Although benefits of cooperative breeding are typically thought of in terms of increased mean reproductive success, it has recently been proposed that this phenomenonmay be a bet-hedging strategy that reduces variance in reproductive success (fecundity variance) inpopulations living inhighly variable environments. We tested this hypothesis using long-term data on the polygynandrous acorn woodpecker (Melanerpes formicivorus). In general, fecundity variance decreased with increasing sociality, at least when controlling for annual variation in ecological conditions. Nonetheless, decreased fecundity variance was insufficient to compensate for reduced per capita reproductive success of larger,more social groups, which typically suffered lower estimatedmean fitness.We did, however, find evidence that sociality in the form of larger group size resulted in increased fitness in years following a small acorn crop due to reduced fecundity variance. Bet-hedging, although not the factor driving sociality in general, may play a role in driving acorn woodpecker group living when acorns are scarce and ecological conditions are poor

Comparative reproductive success of Yellow-shafted, Red-shafted, and Hybrid Flickers across a hybrid zone

Alternative hypotheses of hybrid zones make specific predictions about reproductive components of fitness in the hybrids. The dynamic-equilibrium and reinforcement hypotheses are premised on reduced hybrid fitness, which should be apparent as reduced clutch or brood size or as increased embryonic mortality. The hybrid-superiority and introgression hypotheses predict normal clutch and brood size and embryonic mortality. Reproductive success was measured at four study sites on a transect across the hybrid zone between the Yellow- (Colaptes auratus auratus) and Red-shafted (C. a. cafer) subspecies of the Northern Flicker. Two additional clutch size samples representing pure Yellow- and Redshafted flickers were obtained from museum egg collections. Mean clutch size did not differ significantly among the six samples. Factorial ANOVAs showed that early clutches and broods are larger than late clutches and broods, but no significant difference was detected between hybrid and parental study sites. Analyses of the effect of phenotype (yellow-shafted, red-shafted, hybrid) also suggest that neither clutch size nor brood size is affected, with the exception that hybrid males sired significantly smaller broods. Finally, there were no significant effects of type of cross (red-shafted male x hybrid female, etc.) on the ratio broodsize / clutch-size. The only evidence for reduced hybrid fitness was in the test where males with hybrid phenotypes appear to have sired small broods. This may indicate that abnormal behavior of hybrid males affects female fecundity, but it is also plausible that this marginally significant result is a type I statistical error. The overall lack of evidence for reduced hybrid fitness is inconsistent with either the dynamic-equilibrium or reinforcement models. Of the two remaining alternatives, the bounded hybrid-superiority model appears the more likely explanation of the Northern Flicker hybrid zone because earlier work (Moore and Buchanan 1985) showed that the hybrid zone is not becoming broader, as predicted by the introgression model

Brooding, Provisioning, and Compensatory Care in the Cooperatively Breeding Acorn Woodpecker

We analyzed reproductive investment in parental care (brooding and the provisioning of nestlings) in the acorn woodpecker (Melanerpes formicivorus), a cooperatively breeding species in which both polygynandry and helping-at-the-nest are common. As predicted based on the strategies pursued by birds of different sex and status, breeders generally invested more in parental care than helpers, and breeder females invested more than breeder males. Contrary to expectations, however, the degree to which individuals reduced their effort with increasing group size (i.e., patterns of load lightening or compensatory care) did not match overall investment. Instead, as group size increased, there was no significant difference in compensation in either brooding or provisioning among the different categories of birds. Compensation, at least by breeders, was significantly lower during the first week of the nestling period than later on, supporting the hypothesis that compensatory reduction in care is less likely when brood reduction is more common and was not affected by the acorn crop, which had no significant effect on the incidence of brood reduction despite being important to overall reproductive success. Our results offer support for the hypothesis that levels of compensation are influenced by the relative importance of brood reduction. More theoretical work, however, will be needed in order to understand the basis for patterns of compensation among individuals of different sex and status