Search results for "CLOCK"
showing 10 items of 230 documents
Nanda-Hamner Curves Show Huge Latitudinal Variation but No Circadian Components in Drosophila Montana Photoperiodism
2021
Insect species with a wide distribution offer a great opportunity to trace latitudinal variation in the photoperiodic regulation of traits important in reproduction and stress tolerances. We measured this variation in the photoperiodic time-measuring system underlying reproductive diapause in Drosophila montana, using a Nanda-Hamner (NH) protocol. None of the study strains showed diel rhythmicity in female diapause proportions under a constant day length (12 h) and varying night lengths in photoperiods ranging from 16 to 84 h at 16°C. In the northernmost strains (above 55°N), nearly all females entered diapause under all photoperiods and about half of them even in continuous darkness, while…
Arylalkylamine N-acetyltransferase gene expression in retina and pineal gland of rats under various photoperiods
2004
Abstract The present study examines how the circadian oscillators in the retina and the suprachiasmatic nucleus (SCN) respond to changes in photoperiod. ArylalkylamineN-acetyltransferase (aa-nat) gene expression studied by quantitative RT-PCR revealed that in adult Sprague–Dawley rats kept under different light–dark (LD) cycles for two weeks the temporal pattern of AA-NAT mRNA expression was identical in retina and pineal gland. In both tissues, the time span between the onset of darkness and the nocturnal rise in AA-NAT mRNA expression was 3 h under LD 20:4, 6 h under LD 12:12, and 15 h under LD 4:20. As aa-nat expression in the pineal gland is regulated by the circadian oscillator in SCN,…
<i>Microcnemum coralloides</i> (Chenopodiaceae- Salicornioideae): an example of intraspecific East-West disjunctions in the Mediterranean…
2008
Kadereit, G. & A.E. Yaprak. 2008. Microcnemum coralloides (Chenopodiaceae-Salicornioideae): an example of intraspecific East-West disjunctions in the Mediterranean region. Anales Jard. Bot. Madrid 65(2): 415-426. Microcnemum is a monotypic genus of Salicornioideae comprising rare, annual, hygrohalophytic herbs growing in hypersaline inland lagoons and salt pans. Microcnemum coralloides shows an East-West disjunction in the Mediterranean region: M. coralloides subsp. coralloides occurs in central and eastern Spain while M. coralloides subsp. anatolicum grows in Turkey, Syria, Armenia and Iran. We studied the phylogeny, biogeography and morphological differentiation of M. coralloides. Molecul…
Understanding Mediterranean‐Californian disjunctions: molecular evidence from Chenopodiaceae‐Betoideae
2006
Chenopodiaceae subfam. Betoideae is distributed in both western Eurasia (four genera) and western North America (one genus). To understand the origin of this disjunction, the phylogeny of the subfamily was reconstructed and dated using ndhF, matK/trnK, tmL-trnF spacer, and ITS sequence variation, penalized likelihood and Langley-Fitch, and calibration with three different fossils. Maximum Parsimony and Maximum Likelihood analyses of the molecular data show that Betoideae are monophyletic, but that relationships of the Himalayan Acroglochin, traditionally included in Betoideae because of the shared possession of a circumscissile capsule, are uncertain. Among the betoidean genera, Beta (excl.…
Systematics and phylogeography of the genus Tigriopus (Copepoda, Harpacticoida, Harpacticidae) in the basin of the Mediterranean Sea
2020
[ES] El género de copépodos Tigriopus Norman, 1869 se distribuye en todo el mundo en piscinas costeras de rocas y actualmente se considera que incluye 15 especies válidas. Tigriopus fulvus (Fischer, 1860), con su subespecie Tigriopus fulvus adriaticus Van Douwe 1913 y Tigriopus fulvus algiricus Monard 1935, actualmente se informa que ocurren en el área mediterránea, pero actualmente se desconoce la diversidad real del género. Nuestro objetivo fue evaluar la identidad real de las poblaciones mediterráneas de Tigriopus y dilucidar su taxonomía y patrón de diversidad genética. Para alcanzar estos objetivos, utilizamos dos enfoques diferentes. El primero, basado en la morfología, donde las posi…
Palaeomagnetism of the central Cuban Cretaceous Arc sequences and geodynamic implications
2009
Abstract A detailed palaeomagnetic study of Cretaceous age volcanic and sedimentary arc rocks from central Cuba has been carried out. Samples from 32 sites (12 localities) were subjected to detailed demagnetisation experiments. Nineteen sites from the Los Paso, Matagua, Provincial and Cabaiguan Formations yielded high unblocking temperature, dual polarity directions of magnetisation which pass the fold tests with confidence levels of 95% or more and are considered to be primary in origin. The palaeomagnetic inclinations are equivalent to palaeolatitudes of 9°N for the Aptian, 18°N for the Albian. A synfolding remanence identified in 5 sites from the younger Hilario Formation indicates a lat…
Interference between shallow and deep-seated structures in the Sicilian fold and thrust belt.
2010
Abstract: The fold and thrust belt in western Sicily is characterized by the presence and interference of shallow and deep-seated compressional structures, which were generated and developed at different structural levels. The shallow structures consist of imbricated thrusts and asymmetric folds, with a typical wavelength of 2 km, involving relatively thin deep-water units. These units are superimposed on thick platform carbonate units, along a wide and originally almost flat floor thrust. The axial trend of the folds is variable, as multi-phase folding often occurred, producing a characteristic interference pattern, reflecting continuous variations of the apparent transport direction durin…
A regional-scale discontinuity in western Sicily revealed by a multidisciplinary approach: A new piece for understanding the geodynamic puzzle of the…
2015
The results of an integrated stratigraphic, structural, geophysical, and geochemical study reveal the presence of a crustal discontinuity in western Sicily that, at present, runs roughly N-S along a band from San Vito Lo Capo to Sciacca (SVCS). The boundary between the two zones of this discontinuity is nearly orthogonal to the main thrust propagation of the Sicilian thrust-and-fold belt. The different Permian to Tertiary sedimentary evolution recorded by the two zones appears related to this discontinuity, with thick carbonate platforms in the western sector facing deep-water successions in the eastern one. The presence of Upper Triassic reefs, huge megabreccias bodies, and widespread subm…
Rift nucleation, rift propagation and the creation of basement micro-plates within active rifts
2008
Abstract In this contribution we study the dynamics of rift nucleation and the interaction of propagating rift segments. We use the East African Rift System (EARS) as a case study with special emphasis on the Albertine rift system situated within the western branch of the EARS with the 5000 m high Rwenzori horst, a basement block that was captured by two rift segments. Fieldwork in the Rwenzori mountains shows that the range is not only affected by range parallel faults but that major fault sets cut across the Rwenzoris. In order to understand these complex fault patterns and the dynamics of the process that leads to the capturing of basement blocks within the extending rift system we devel…
Mortality associations with DNA methylation-based biological aging and physical functioning measures across a 20-year follow-up period
2023
Background Measures of biological aging range from DNA methylation (DNAm)-based estimates to measures of physical abilities. The purpose of this study was to compare DNAm- and physical functioning-based measures of biological aging in predicting mortality. Methods We studied 63- to 76-year-old women (N = 395) from the Finnish Twin Study on Aging (FITSA). Participants’ biological age (epigenetic clocks DNAm GrimAge and DunedinPACE) was estimated using blood DNAm data. Tests of physical functioning conducted under standardized laboratory conditions included the Timed Up and Go (TUG) test and 10-m walk test. Mortality hazard ratios (HRs) were calculated per every one standard deviation (SD) in…