Seasonal variation in testicular and fat-body weight and plasma testosterone and androstenedione concentration in the lizard Cordylus polyzonus (Sauria: Cordylidae)

Seasonal variation in testicular and fat-body weight and plasma testosterone and androstenedione concentration of the lizard Cordylus polyzonus is described. Testicular recrudescence commenced in autumn (April), reaching a peak in early spring (September) and regression followed during mid-spring to early autumn (October-March). The onset of testicular recrudescence coincided with decreasing ambient temperature and photoperiod and increasing rainfall. Fat-body weight was small during most of the testicular recrudescence phase, with an increase commencing in spring (September). A peak in fat-body weight was reached during late spring - midsummer (October-December) and followed by a progressive decline to baseline values in winter. Plasma testosterone and androstenedione concentrations followed a bimodal annual pattern, a first peak occurring in late summer/early autumn (February/March) and the second in spring (September/October).The first peak coincided with the onset of testicular recrudescence and the second with maximum testicular weight

Seasonal variation in plasma and corpus luteum oestradiol-17β and progesterone concentrations of the lizard Cordylus p. polyzonus (Sauria: Cordylidae)

Seasonal variation in plasma and corpus luleum oestradiol-17β and progesterone concentrations of the viviparous lizard Cordylus p. polyzonus is described. Sleroid concentrations were measured by radioimmunoassay. Plasma oeslradiol-17β concentration increased from basal values in late autumn (May) and peaked in mid-spring (October), during which time females were vitellogenin Plasma oestradiol-17β concentration declined to basal values in late spring (November) when females ovulale, remaining low until the onset of the nexl vitellogenic phase in autumn. Plasma progesterone concentrations of previlellogenic and early vilellogenic females (April-July) were basal, but increased during the laler slagas of vilellogenesis (August-October). Following ovulation in November, plasma progesterone concentrations were high throughout pregnancy, declining to basal values in April when parturition occurred. Oestradio-17β was detectable in freshly formed corpora lutea (corpora haemorargica) during the first month of pregnancy (November), but declined to undetectable values thereafter. Corpus luleum progesterone concentration gradually increased as pregnancy proceeded, reaching a peak two months before birth, bul declined thereafter. Progesterone concentration of postpartum degenerating corpora lutea (corpora albicantia) was considerably lower than that of corpora lutea during geslation

National strategy for serological diagnosis of HIV infection

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Observation and Assignment of Silent and Higher Order Vibrations in the Infrared Transmission of C60 Crystals

We report the measurement of infrared transmission of large C60 single crystals. The spectra exhibit a very rich structure with over 180 vibrational absorptions visible in the 100 - 4000 cm-1 range. Many silent modes are observed to have become weakly IR-active. We also observe a large number of higher order combination modes. The temperature (77K - 300K) and pressure (0 - 25KBar) dependencies of these modes were measured and are presented. Careful analysis of the IR spectra in conjunction with Raman scattering data showing second order modes and neutron scattering data, allow the selection of the 46 vibrational modes C60. We are able to fit *all* of the first and second order data seen in the present IR spectra and the previously published Raman data (~300 lines total), using these 46 modes and their group theory allowed second order combinations.Comment: REVTEX v3.0 in LaTeX. 12 pages. 8 Figures by request. c60lon

Study of doubly strange systems using stored antiprotons

Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the P‾ANDA experiment at FAIR. For the first time, high resolution γ-spectroscopy of doubly strange ΛΛ-hypernuclei will be performed, thus complementing measurements of ground state decays of ΛΛ-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Ξ−-atoms will be feasible and even the production of Ω−-atoms will be within reach. The latter might open the door to the |S|=3 world in strangeness nuclear physics, by the study of the hadronic Ω−-nucleus interaction. For the first time it will be possible to study the behavior of Ξ‾+ in nuclear systems under well controlled conditions

Seasonal variation in plasma and corpus luteum oestradiol-17B and progesterone concentrations of the lizard Cordylus p. polyzonus (Sauria: Cordylidae)

The original publication is available at http://africanzoology.journals.ac.za/pubSeasonal variation in plasma and corpus luteum oestradiol-17B and progesterone concentrations of the viviparous lizard Cordylus p. potyzonus is described. Steroid concentrations were measured by radioimmunoassay. Plasma oestradiol-17B concentration increased from basal values in late autumn (May) and peaked in mid-spring (October), during which time females were vitellogenic. Plasma oestradiol-17B concentration declined to basal values in the late spring (November) when female ovulate, remaining low until the onset of tne next vitellofenic phase in autum. Plasma progesterone concentrations of previtellogenic and early vitellogenic females (April-July) were basal, but increased during the later stages of vitellogenesis (August-October). Following ovulation in November, plasma progesteronec oncentrations were high throughout pregnancy, declining to basal values in April when parturition occurred. Oestradiol-17B was detectable in freshly formed corpora lutea (corpora haemorargica) during the first month of pregnancy (November), but declined to undetectable values thereafter. Corpus luteum progesterone concentratlon gradually increased as pregnancy proceeded, reaching a peak two months before birth, but declined thereafter. Progesterone concentration of postpartum degenerating corpora lutea (corpora albicantia) was considerably lower than that of corpora lutea during gestation.Publisher's versio

Invasive implantation and intimate placental associations in a placentotrophic African lizard, Trachylepis ivensi (Scincidae)

In the viviparous lizard Trachylepis ivensi (Scincidae) of central Africa, reproducing females ovulate tiny ~1 mm eggs and supply the nutrients for development by placental means. Histological study shows that this species has evolved an extraordinary placental pattern long thought to be confined to mammals, in which fetal tissues invade the uterine lining to contact maternal blood vessels. The vestigial shell membrane disappears very early in development, allowing the egg to absorb uterine secretions. The yolk is enveloped precocially by the trilaminar yolk sac and no isolated yolk mass or yolk cleft develops. Early placentas are formed from the chorion and choriovitelline membranes during the neurula through pharyngula stages. During implantation, cells of the chorionic ectoderm penetrate between uterine epithelial cells. The penetrating tissue undergoes hypertrophy and hyperplasia, giving rise to sheets of epithelial tissue that invade beneath the uterine epithelium, stripping it away. As a result, fetal epithelium entirely replaces the uterine epithelium, and lies in direct contact with maternal capillaries and connective tissue. Placentation is endotheliochorial and fundamentally different from that of all other viviparous reptiles known. Further, the pattern of fetal membrane development (with successive loss and re-establishment of an extensive choriovitelline membrane) is unique among vertebrates. T. ivensi represents a new extreme in placental specializations of reptiles, and is the most striking case of convergence on the developmental features of viviparous mammals known. © 2011 Wiley Periodicals, Inc

Geographic variation in sexual size dimorphism in the rock agama, Agama atra (Sauria: Agamidae)

Significant sexual dimorphism in overall size occurs in the rock agama, Agama atra (Sauria; Agamidae), with males growing larger than females. Geographic variation in the degree of sexual size dimorphism also exists, males growing significantly larger than females in Namaqualand and Namibia compared to populations in other areas. Sexual differences in scaling of head, limb and tail dimensions were mainly the result of differential asymptotic sizes reached by the sexes. Head size was also influenced by a faster increase in head dimensions with increasing snout to vent length in males compared to females, probably as a result of sexual selection. In females, scaling of limb and tail dimensions was decreased compared to males, possibly a result of differential energy allocation to reproduction.Articl

Geographic variation in sexual size dimorphism in the rock agama, Agama atra (Sauria: Agamidae)

Significant sexual dimorphism in overall size occurs in the rock agama, Agama atra (Sauria; Agamidae), with males growing larger than females. Geographic variation in the degree of sexual size dimorphism also exists, males growing significantly larger than females in Namaqualand and Namibia compared to populations in other areas. Sexual differences in scaling of head, limb and tail dimensions were mainly the result of differential asymptotic sizes reached by the sexes. Head size was also influenced by a faster increase in head dimensions with increasing snout to vent length in males compared to females, probably as a result of sexual selection. In females, scaling of limb and tail dimensions was decreased compared to males, possibly a result of differential energy allocation to reproduction.Key words: sexual size dimorphism, head size, limb size, tail size, scaling

Grouping behaviour, tail-biting behaviour and sexual dimorphism in the armadillo lizard (Cordylus cataphractus) from South Africa

Grouping behaviour, tail-biting behaviour and sexual dimorphism were investigated in Cordylus cataphractus, a rock-dwelling lizard from South Africa. Eighty-five per cent of individuals collected during different seasons occurred in groups of two or more, which shows that grouping behaviour is a year-round phenomenon in this species. Group size ranged from one to approximately 30. Groups smaller than nine individuals normally included only one adult male, but larger groups often had more than one. Sixty-eight per cent of lone individuals were adult males. All individuals (n = 134) attempted to bite their tails and roll into a ball on collection. Cordylus cataphractus prefers horizontal crevices with an accompanying ledge on which animals can perch in close proximity to the crevice. Males apparently reach larger asymptotic body sizes than females and also have larger heads and longer tails. The higher incidence of scars among males suggests that sexual dimorphism could result from sexual selection, but sexual differences in scaling of head and tail dimensions, however, suggest that the dimorphism may be the result of differential energy allocation by females. Unlike most other Cordylus species which have female-biased sex ratios, the ratio is close to one in C cataphractus.Articl