Parental cooperation in a changing climate: fluctuating environments predict shifts in care division

Aim: Parental care improves the survival of offspring and therefore has a major impact on reproductive success. It is increasingly recognized that coordinated biparental care is necessary to ensure the survival of offspring in hostile environments, but little is known about the influence of environmental fluctuations on parental cooperation. Assessing the impacts of environmental stochasticity, however, is essential for understanding how populations will respond to climate change and the associated increasing frequencies of extreme weather events. Here we investigate the influence of environmental stochasticity on biparental incubation in a cosmopolitan ground-nesting avian genus. Location: Global. Methods: We assembled data on biparental care in 36 plover populations (Charadrius spp.) from six continents, collected between 1981 and 2012. Using a space-for-time approach we investigate how average temperature, temperature stochasticity (i.e. year-to-year variation) and seasonal temperature variation during the breeding season influence parental cooperation during incubation. Results: We show that both average ambient temperature and its fluctuations influence parental cooperation during incubation. Male care relative to female care increases with both mean ambient temperature and temperature stochasticity. Local climatic conditions explain within-species population differences in parental cooperation, probably reflecting phenotypic plasticity of behaviour. Main conclusions: The degree of flexibility in parental cooperation is likely to mediate the impacts of climate change on the demography and reproductive behaviour of wild animal populations.</p

Magnetic and medicinal properties of lanthanides

Two distinct projects involving the use of lanthanide metal ions are discussed in this thesis. In the first study, the magnetic interactions in heterometallic d/f complexes were investigated. The most powerful permanent magnet known to date consists of a Nd-Fe core; however, the magnetic exchange between these two metal ions is poorly understood. By purposeful design, new cationic d/f complexes using a multidentate amine phenol ligand were synthesized that selectively coordinate divalent first row d-block transition metal ions (TM) and lanthanides (Ln) in close proximity, a feature desirable for magnetic studies. The synthesis, characterization, and magnetic studies of the d/f cluster complexes with the formula [LnTM₂(bcn)₂]⁺, where H₃bcn = tris-N,N',N" -(2-hydroxybenzyl)-1,4,7-triazocyelononane), TM(II) = Zn, Cu and Ni, and Ln(III)= La, Nd, Gd, Dy and Yb are discussed herein. In addition, the core structure of [TM(Hbcn)], [TM₂(bcn)₃], [La(bcn)], and [La₃(bcn)₂] have been examined. Select magnetic studies were also completed on a similar trimetallic d/f species, [LnNi₂(tam)₂]⁺, where H₃tam = tris-1,1,1-(((2-hydroxybenzyl)amino) methyl)ethane, and Ln(III) = Gd, Dy and Yb, used to compare the magnetic behaviors between geometrically diverse TM(II)-Ln(III) systems. The second study illustrates the usefulness of Ln(III) in metallopharmaceuticals. La(III) ions are known to be functional mimics of Ca(II) ions and have been shown to affect the bone remodeling cycle. Exploiting this disruption to the homeostasis of bone has potential for the treatment of bone density disorders, such as osteoporosis. In an effort to find new orally active agents for these disorders, a series of Ln(III) containing complexes incorporating small, non-toxic, bidentate pyrone and pyridinone ligands have been synthesized and characterized (LnL₃, Ln(III) = La, Eu, Gd, Tb, Yb, L = 3-oxy-2-methyl-4-pyrone (ma-), 3-oxy-2-ethyl-4-pyrone (ema-), 3-oxy-1,2-dimethyl-4-pyridinone (dpp-) and 3-oxy-2-methyl-4(1H)-pyridinone (mpp-)). Preliminary biological analyses undertaken in this thesis include cytotoxicity, cell uptake and bidirectional transport studies in Caco-2 cells and in vitro hydroxyapatite (HA) binding studies analyzed by ICP-MS, fluorescence assays, UV-vis spectrophotometric assays and IR. The LnL₃ species were found to have IC₅₀ values at least 6 times greater than that of cisplatin, ≥98% HA-binding capacity, and permeability coefficients in the moderate range.Science, Faculty ofChemistry, Department ofGraduat

A Modular Laser Apparatus for Polarimetry Nephelometry, and Fluorimetry in General Chemistry

An introduction to lasers as early as a general chemistry course can be of great advantage to both major and non major students in chemistry, but often cost and other practical considerations prevent widespread use of lasers. A versatile laser apparatus suitable for the undergraduate teaching laboratory that may serve as polarimeter, nephelometer, or fluorimeter is described

A Modular Laser Apparatus for Polarimetry, Nephelometry, and Fluorimetry in General Chemistry

An introduction to lasers as early as a general chemistry course can be of great advantage to both major and non major students in chemistry, but often cost and other practical considerations prevent widespread use of lasers. A versatile laser apparatus suitable for the undergraduate teaching laboratory that may serve as polarimeter, nephelometer, or fluorimeter is described

Parental cooperation in a changing climate: fluctuating environments predict shifts in care division

K