Pleistocene phylogeographic effects on avian populations and the speciation process.

Pleistocene biogeographic events have traditionally been ascribed a major role in promoting speciations and in sculpting the present-day diversity and distributions of vertebrate taxa. However, this paradigm has recently come under challenge from a review of interspecific mtDNA genetic distances in birds: most sister-species separations dated to the Pliocene. Here we summarize the literature on intraspecific mtDNA phylogeographic patterns in birds and reinterpret the molecular evidence bearing on Pleistocene influences. At least 37 of the 63 avian species surveyed (59%) are sundered into recognizable phylogeographic units, and 28 of these separations (76%) trace to the Pleistocene. Furthermore, use of phylogroup separation times within species as minimum estimates of 'speciation durations' also indicates that many protracted speciations, considered individually, probably extended through time from Pliocene origins to Pleistocene completions. When avian speciation is viewed properly as an extended temporal process rather than as a point event, Pleistocene conditions appear to have played an active role both in initiating major phylogeographic separations within species, and in completing speciations that had been inaugurated earlier. Whether the Pleistocene was exceptional in these regards compared with other geological times remains to be determined

Sex-linked markers facilitate genetic parentage analyses in knobbed whelk broods.

To explore the potential of sex-linked polymorphisms for genetic parentage analyses in natural populations, we have employed a recently discovered "X-linked" microsatellite marker (in conjunction with polymorphic autosomal loci) to deduce biological paternity and maternity for large numbers of encapsulated embryos within individual broods of the knobbed whelk (Busycon carica). Empirical findings illustrate how such sex-linked genetic tags can in special instances find at least three novel utilities in genetic dissections of large-clutch species: clarification of paternity assignments that had remained ambiguous from di-locus autosomal data alone; elucidation of linkage relationships among pairs of autosomal loci; and illumination of maternity (and thereby paternity also) in broods for which neither biological parent was known from independent evidence

Comparison of human uterine cervical electrical impedance measurements derived using two tetrapolar probes of different sizes

BACKGROUND We sought to compare uterine cervical electrical impedance spectroscopy measurements employing two probes of different sizes, and to employ a finite element model to predict and compare the fraction of electrical current derived from subepithelial stromal tissue. METHODS Cervical impedance was measured in 12 subjects during early pregnancy using 2 different sizes of the probes on each subject. RESULTS Mean cervical resistivity was significantly higher (5.4 vs. 2.8 Ωm; p < 0.001) with the smaller probe in the frequency rage of 4–819 kHz. There was no difference in the short-term intra-observer variability between the two probes. The cervical impedance measurements derived in vivo followed the pattern predicted by the finite element model. CONCLUSION Inter-electrode distance on the probes for measuring cervical impedance influences the tissue resistivity values obtained. Determining the appropriate probe size is necessary when conducting clinical studies of resistivity of the cervix and other human tissues

Multiple paternity and female sperm usage along egg-case strings of the knobbed whelk, Busycon carica (Mollusca; Melongenidae)

We used genotypic data from three highly polymorphic microsatellite loci (two autosomal and one sex-linked) to examine micro-spatial and temporal arrangements of genetic paternity for more than 1,500 embryos housed along 12 egg-case strings of the knobbed whelk, Busycon carica. Multiple paternity proved to be the norm in these single-dam families, with genetic contributions of several sires (at least 3.5 on average) being represented among embryos within individual egg capsules as well as along the string. Two strings were studied in much greater detail; five and seven fathers were identified, none of which was among the several males found in consort with the female at her time of egg-laying. Each deduced sire had fathered roughly constant proportions of embryos along most of the string, but those proportions differed consistently among fathers. A few significant paternity shifts at specifiable positions along an egg-case string were also observed. Although the precise physical mechanisms inside a female whelk's reproductive tract remain unknown, our genetic findings indicate that successive fertilization events (and/or depositions of zygotes into egg capsules) normally occur as near-random draws from a well-but-not-perfectly blended pool of gametes (or zygotes) stemming from stored ejaculates, perhaps in different titers, of a dam's several mates. © 2006 Springer-Verlag

Tuning reaction products by constrained optimisation

We describe an effective means of defining optimisation criteria for self-optimising reactors, applicable to situations where a compromise is sought between several competing objectives. The problem is framed as a constrained optimisation, in which a lead property is optimised subject to constraints on the values that other properties may assume. Compared to conventional methods (using weighted-sum- and weighted-product-based merit functions), the approach described here is more intuitive, easier to implement, and yields an optimised solution that more faithfully reflects user preferences. The method is applied here to the synthesis of o-xylenyl adducts of Buckminsterfullerene, using a cascadic reaction of the form X0 → X1 → X2 → … XN. Specifically, we selectively target the formation of the (technologically useful) first- and second-order adducts X1 and X2, while at the same time suppressing the formation of unwanted higher-order products. More generally, the approach is applicable to any chemical optimisation involving a trade-off between competing criteria. To assist with implementation we provide a self-contained software package for carrying out constrained optimisation, together with detailed tutorial-style instructions

Comparative metabolism as a key driver of wildlife species sensitivity to human and veterinary pharmaceuticals

Human and veterinary drug development addresses absorption, distribution, metabolism, elimination and toxicology (ADMET) of the Active Pharmaceutical Ingredient (API) in the target species. Metabolism is an important factor in controlling circulating plasma and target tissue API concentrations and in generating metabolites which are more easily eliminated in bile, faeces and urine. The essential purpose of xenobiotic metabolism is to convert lipid-soluble, non-polar and non-excretable chemicals into water soluble, polar molecules that are readily excreted. Xenobiotic metabolism is classified into Phase I enzymatic reactions (which add or expose reactive functional groups on xenobiotic molecules), Phase II reactions (resulting in xenobiotic conjugation with large water-soluble, polar molecules) and Phase III cellular efflux transport processes. The human-fish plasma model provides a useful approach to understanding the pharmacokinetics of APIs (e.g. diclofenac, ibuprofen and propranolol) in freshwater fish, where gill and liver metabolism of APIs have been shown to be of importance. By contrast, wildlife species with low metabolic competency may exhibit zero-order metabolic (pharmacokinetic) profiles and thus high API toxicity, as in the case of diclofenac and the dramatic decline of vulture populations across the Indian subcontinent. A similar threat looms for African Cape Griffon vultures exposed to ketoprofen and meloxicam, recent studies indicating toxicity relates to zero-order metabolism (suggesting P450 Phase I enzyme system or Phase II glucuronidation deficiencies). While all aspects of ADMET are important in toxicity evaluations, these observations demonstrate the importance of methods for predicting API comparative metabolism as a central part of environmental risk assessment

Origin Gaps and the Eternal Sunshine of the Second-Order Pendulum

The rich experiences of an intentional, goal-oriented life emerge, in an unpredictable fashion, from the basic laws of physics. Here I argue that this unpredictability is no mirage: there are true gaps between life and non-life, mind and mindlessness, and even between functional societies and groups of Hobbesian individuals. These gaps, I suggest, emerge from the mathematics of self-reference, and the logical barriers to prediction that self-referring systems present. Still, a mathematical truth does not imply a physical one: the universe need not have made self-reference possible. It did, and the question then is how. In the second half of this essay, I show how a basic move in physics, known as renormalization, transforms the "forgetful" second-order equations of fundamental physics into a rich, self-referential world that makes possible the major transitions we care so much about. While the universe runs in assembly code, the coarse-grained version runs in LISP, and it is from that the world of aim and intention grows.Comment: FQXI Prize Essay 2017. 18 pages, including afterword on Ostrogradsky's Theorem and an exchange with John Bova, Dresden Craig, and Paul Livingsto

Severe transient left ventricular dysfunction induced by thyrotoxicosis

We report on a 44-year-old woman presenting with chest pain and dyspnoea without previous stress-related events. By means of echocardiography severe left ventricular dysfunction and wall motion abnormalities resembling stress-induced cardiomyopathy (Tako Tsubo) were seen. Laboratory investigation revealed thyrotoxicosis and elevated cardiac markers. Six days after starting medical treatment, complete restoration of the left ventricular function was observed. The transient left ventricular dysfunction was induced by thyrotoxicosis resembling stress-induced cardiomyopathy that resolved completely after medical treatment