Development of the Innate Immune Response in NestlingTree Swallows (Tachycineta bicolor)

The innate immune system provides an immediate, short term, first line of defense from pathogens; its appearance early in development in vertebrates is evidence of its critical importance. Even so, few studies have investigated the development of the immune response as juveniles transition into adults. Ultimately, the ability to respond to pathogens confers fitness benefits in terms of health, survival, and reproductive success, and it follows that functions such as rapid growth cannot be fully met simultaneously since energy is a limiting resource. As a result, defense mechanisms are compromised at an early age due to energy allocation to rapid growth; therefore, immunity should increase as individuals mature. I studied the development of innate immunity in nestling Tree Swallows using microbicidal assays which were conducted in vitro to assess the ability of the immune system to kill E. coli via lysis. This research may provide insight into patterns of disease susceptibility, which in turn influence evolutionary fitness and population dynamics

Molecular ratchets - verification of the principle of detailed balance

We argue that the recent experiments of Kelly et. al.(Angew. Chem. Int. Ed. Engl. 36, 1866 (1997)) on molecular ratchets, in addition to being in agreement with the second law of thermodynamics, is a test of the principle of detailed balance for the ratchet. We suggest new experiments, using an asymmetric ratchet, to further test the principle. We also point out methods involving a time variation of the temperature to to give it a directional motion

Remote sensing of tidal networks and their relation to vegetation

The study of the morphology of tidal networks and their relation to salt marsh vegetation is currently an active area of research, and a number of theories have been developed which require validation using extensive observations. Conventional methods of measuring networks and associated vegetation can be cumbersome and subjective. Recent advances in remote sensing techniques mean that these can now often reduce measurement effort whilst at the same time increasing measurement scale. The status of remote sensing of tidal networks and their relation to vegetation is reviewed. The measurement of network planforms and their associated variables is possible to sufficient resolution using digital aerial photography and airborne scanning laser altimetry (LiDAR), with LiDAR also being able to measure channel depths. A multi-level knowledge-based technique is described to extract networks from LiDAR in a semi-automated fashion. This allows objective and detailed geomorphological information on networks to be obtained over large areas of the inter-tidal zone. It is illustrated using LIDAR data of the River Ems, Germany, the Venice lagoon, and Carnforth Marsh, Morecambe Bay, UK. Examples of geomorphological variables of networks extracted from LiDAR data are given. Associated marsh vegetation can be classified into its component species using airborne hyperspectral and satellite multispectral data. Other potential applications of remote sensing for network studies include determining spatial relationships between networks and vegetation, measuring marsh platform vegetation roughness, in-channel velocities and sediment processes, studying salt pans, and for marsh restoration schemes

Bioerosion on shore platforms developed in the Waitemata Formation, Auckland

Bioerosion - the removal of lithic substrate by the erosive activities of living organisms- has not previously been discussed for New Zealand shore platforms. This paper aims at drawing attention to bioerosion as a process active in shore platform development. Detailed reference is made to bioerosion occurring on the alternating sandstones and siltstones of the Waitemata Formation found outcropping on the coastline around Auckland. In this area several facets of shore platform morphology may be attributed to the direct effects of boring and browsing marine organisms. A classification of animals causing bioerosion, based on mechanism of erosion, is presented, and the geomorphic significance of the various groups discussed

Strontium isotope stratigraphy: LOWESS version 3: best fit to the marine Sr-isotope curve for 0-509 Ma and accompanying look-up table for deriving numerical age

An improved and updated version of the statistical LOWESS fit to the marine 87Sr/86Sr record and a revised look-up table (V3:10/99; available from [email protected]) based upon it enables straightforward conversion of 87Sr/86Sr to numerical age, and vice versa, for use in strontium isotope stratigraphy (SIS). The table includes 95% confidence intervals on predictions of numerical age from 87Sr/86Sr. This version includes the Triassic and Paleozoic record (0-509 Ma) omitted from previous versions because of the paucity of adequate data at the time of preparation. We highlight differences between the previous versions of the table and the current version and discuss some aspects of the 87Sr/86Sr record that may have geological significance. We give examples of how the table can be used and where it has proven useful

Testes asymmetry, condition and sexual selection in birds: an experimental test

The functional significance of the marked directional asymmetry in testes size observed in many bird species is obscure. Møller suggested that (i) the smaller of the two testes serves a compensatory role and increases in size (and hence reduces asymmetry) when the larger one is defective in some way, and (ii) as a consequence, the degree of directional asymmetry in testes size reflects male quality and covaries positively with the expression of secondary sexual traits.We conducted an experimental test of these two hypotheses in the zebra finch,Taeniopygia guttata. Neither hypothesis was supported. First, there was no significant relationship between the size of the left testis and relative testes asymmetry. Second, we obtained no support for the hypothesis that the degree of directional asymmetry in testes mass covaried with condition. On the contrary, directional asymmetry in testes mass was signifcantly greater in birds whose condition was experimentally reduced, compared with control birds. Moreover, we found no significant relationships between testes asymmetry and secondary sexual traits. We conclude that directional asymmetry in testes size does not reflect male condition in the zebra finch

Dust from Australia- A reappraisal

This paper reviews the meteorological events of October 1928 associated with severe duststorms in Australia and subsequent transport of dust to New Zealand. In the light of contemporary knowledge of the jet streams, and from reappraisal of the original synoptic charts, reported meteorological conditions and press reports pertaining to these duststorms, it is postulated that for dust to be deposited upon New Zealand within 24 hours, of duststorms in Australia it presumably travelled via the jet stream region of the' middle and upper troposphere

Dividing the Indivisible: Procedures for Allocating Cabinet Ministries to Political Parties in a Parliamentary System

Political parties in Northern Ireland recently used a divisor method of apportionment to choose, in sequence, ten cabinet ministries. If the parties have complete information about each others' preferences, we show that it may not be rational for them to act sincerely by choosing their most-preferred ministry that is available. One consequence of acting sophisticatedly is that the resulting allocation may not be Pareto-optimal, making all the parties worse off. Another is nonmonotonicty-choosing earlier may hurt rather than help a party. We introduce a mechanism that combines sequential choices with a structured form of trading that results in sincere choices for two parties. Although there are difficulties in extending this mechanism to more than two parties, other approaches are explored, such as permitting parties to making consecutive choices not prescribed by an apportionment method. But certain problems, such as eliminating envy, remain.APPORTIONMENT METHODS; CABINETS; SEQUENTIAL ALLOCATION; MECHANISM DESIGN; FAIRNESS

A common beta-sheet architecture underlies in vitro and in vivo beta(2)-microglobulin amyloid fibrils

Misfolding and aggregation of normally soluble proteins into amyloid fibrils and their deposition and accumulation underlies a variety of clinically significant diseases. Fibrillar aggregates with amyloid-like properties can also be generated in vitro from pure proteins and peptides, including those not known to be associated with amyloidosis. Whereas biophysical studies of amyloid-like fibrils formed in vitro have provided important insights into the molecular mechanisms of amyloid generation and the structural properties of the fibrils formed, amyloidogenic proteins are typically exposed to mild or more extreme denaturing conditions to induce rapid fibril formation in vitro. Whether the structure of the resulting assemblies is representative of their natural in vivo counterparts, thus, remains a fundamental unresolved issue. Here we show using Fourier transform infrared spectroscopy that amyloid-like fibrils formed in vitro from natively folded or unfolded β2-microglobulin (the protein associated with dialysis-related amyloidosis) adopt an identical β-sheet architecture. The same β-strand signature is observed whether fibril formation in vitro occurs spontaneously or from seeded reactions. Comparison of these spectra with those of amyloid fibrils extracted from patients with dialysis-related amyloidosis revealed an identical amide I' absorbance maximum, suggestive of a characteristic and conserved amyloid fold. Our results endorse the relevance of biophysical studies for the investigation of the molecular mechanisms of β2-microglobulin fibrillogenesis, knowledge about which may inform understanding of the pathobiology of this protein