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Maternal inbreeding reduces parental care in the zebra finch, <i>Taeniopygia guttata</i>
Increased embryo mortality is the most commonly cited cause of reduced fitness in inbred organisms. Reduced embryo survival may be the result of reduced parental expenditure by inbred individuals and here we tested the hypothesis that inbreeding results in impaired incubation behaviour in captive zebra finches. We compared incubation attentiveness of inbred female zebra finches (derived from full-sibling mating) with that of control females (derived from unrelated parents) and found a statistically significant inbreeding depression of 17% in incubation attentiveness. This shows that inbreeding can significantly influence parental behaviour. Despite a reduction in the amount of time inbred females spent incubating, their partners were able to compensate for the reduced incubation attentiveness. Incubation temperature also did not differ between inbred and control females. To test for the effect of incubation behaviour, we fostered eggs laid by control females to either inbred or control females at the end of laying. Eggs that were incubated by inbred females had an 8.5% lower hatching success than eggs incubated by control females and, although based on a relatively small sample and not statistically significant, the magnitude of the difference was consistent with differences in hatching success observed in the wild under relatively benign environmental conditions. Thus, under more challenging environmental conditions usually encountered in the wild, the reduced incubation attentiveness of inbred females could provide one proximate explanation for the consistent finding of decreased hatching success with increasing maternal inbreeding in birds
Activation of type II calcium/calmodulin-dependent protein kinase by Ca^(2+)/calmodulin is inhibited by autophosphorylation of threonine within the calmodulin-binding domain
It is now well established that autophosphorylation of a threonine residue located next to each calmodulin-binding domain in the subunits of type II Ca^(2+)/calmodulin-dependent protein kinase causes the kinase to remain active, although at a reduced rate, after Ca^(2+) is removed from the reaction. This autophosphorylated form of the kinase is still sensitive to Ca2+/calmodulin, which is required for a maximum catalytic rate. After removal of Ca^(2+), new sites are autophosphorylated by the partially active kinase. Autophosphorylation of these sites abolishes sensitivity of the kinase to Ca^(2+)/calmodulin (Hashimoto, Y., Schworer, C. M., Colbran, R. J., and Soderling, T. R. (1987) J. Biol. Chem. 262, 8051-8055). We have identified two pairs of homologous residues, Thr^(305) and Ser^(314) in the alpha subunit and Thr^(306) and Ser^(315) in the beta subunit, that are autophosphorylated only after removal of Ca^(2+) from an autophosphorylation reaction. The sites were identified by direct sequencing of labeled tryptic phosphopeptides isolated by reverse-phase high pressure liquid chromatography. Thr^(305-306) is rapidly dephosphorylated by purified protein phosphatases 1 and 2A, whereas Ser^(314-315) is resistant to dephosphorylation. We have shown by selective dephosphorylation that the presence of phosphate on Thr^(305-306) blocks sensitivity of the kinase to Ca^(2+)/calmodulin. In contrast, the presence of phosphate on Ser^(314-315) is associated with an increase in the Kact for Ca^(2+)/calmodulin of only about 2-fold, producing a relatively small decrease in sensitivity to Ca^(2+)/calmodulin
The Isotope Effect in the Displacement of Tritium and Hydrogen From a Nickel Surface
Desorption of chemisorbed tritiated hydrogen by mercury vapour has been investigated to determine whether the surfaces of evaporated nickel films are homogeneous or heterogeneous in chemisorption at 2
Scattering of Woods-Saxon Potential in Schrodinger Equation
The scattering solutions of the one-dimensional Schrodinger equation for the
Woods-Saxon potential are obtained within the position-dependent mass
formalism. The wave functions, transmission and reflection coefficients are
calculated in terms of Heun's function. These results are also studied for the
constant mass case in detail.Comment: 14 page
Making the small oblique parameters large
We compute the oblique parameters, including the three new parameters ,
and introduced recently by the Montreal group, for the case of one
scalar multiplet of arbitrary weak isospin and weak hypercharge . We
show that, when the masses of the heaviest and lightest components of the
multiplet remain constant, but increases, the oblique parameter and
the three new oblique parameters increase like , while only
increases like . For large multiplets with masses not much higher than , the oblique parameters and may become much larger than
and .Comment: 9 pages, standard LATEX, 3 figures available from the authors, report
CMU-HEP93-17 and DOE-ER/40682-4
Fast field-cycling NMR of cartilage : a way toward molecular imaging
Peer reviewedPublisher PD
The Woods-Saxon Potential in the Dirac Equation
The two-component approach to the one-dimensional Dirac equation is applied
to the Woods-Saxon potential. The scattering and bound state solutions are
derived and the conditions for a transmission resonance (when the transmission
coefficient is unity) and supercriticality (when the particle bound state is at
E=-m) are then derived. The square potential limit is discussed. The recent
result that a finite-range symmetric potential barrier will have a transmission
resonance of zero-momentum when the corresponding well supports a half-bound
state at E=-m is demonstrated.Comment: 8 pages, 4 figures. Submitted to JPhys
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