98 research outputs found
Tidal gravity observations at Mt. Etna and Stromboli: results concerning the modeled and observed tidal factors
Continuous gravity observations performed in the last few years, both at Mt. Etna and Stromboli, have prompted
the need to improve the tidal analysis in order to acquire the best corrected data for the detection of volcano
related signals. On Mt. Etna, the sites are very close to each other and the expected tidal factor differences are
negligible. It is thus useful to unify the tidal analysis results of the different data sets in a unique tidal model.
This tidal model, which can be independently confirmed by a modeling of the tidal parameters based on the elastic
response of the Earth to tidal forces and the computation of the ocean tides effects on gravity, is very useful
for the precise tidal gravity prediction required by absolute or relative discrete gravity measurements. The
change in time of the gravimeters’ sensitivity is also an important issue to be checked since it affects not only
the results of tidal analysis but also the accuracy of the observed gravity changes. Conversely, if a good tidal
model is available, the sensitivity variations can be accurately reconstructed so as to retune observed tidal
records with the synthetic tide, since the tidal parameters are assumed to be constant at a given location
The “resort effect”: Can tourist islands act as refuges for coral reef species?
There is global consensus that marine protected areas offer a plethora of benefits to the biodiversity within and around them. Nevertheless, many organisms threatened by human impacts also find shelter in unexpected or informally protected places. For coral reef organisms, refuges can be tourist resorts implementing local environment-friendly bottom-up management strategies. We used the coral reef ecosystem as a model to test whether such practices have positive effects on the biodiversity associated with de facto protected areas.USAI
Characterization of the Interactions between Fluoroquinolone Antibiotics and Lipids: a Multitechnique Approach
Probing drug/lipid interactions at the molecular level represents an important challenge in pharmaceutical research and membrane biophysics. Previous studies showed differences in accumulation and intracellular activity between two fluoroquinolones, ciprofloxacin and moxifloxacin, that may actually result from their differential susceptibility to efflux by the ciprofloxacin transporter. In view of the critical role of lipids for the drug cellular uptake and differences observed for the two closely related fluoroquinolones, we investigated the interactions of these two antibiotics with lipids, using an array of complementary techniques. Moxifloxacin induced, to a greater extent than ciprofloxacin, an erosion of the DPPC domains in the DOPC fluid phase (atomic force microscopy) and a shift of the surface pressure-area isotherms of DOPC/DPPC/fluoroquinolone monolayer toward lower area per molecule (Langmuir studies). These effects are related to a lower propensity of moxifloxacin to be released from lipid to aqueous phase (determined by phase transfer studies and conformational analysis) and a marked decrease of all-trans conformation of acyl-lipid chains of DPPC (determined by ATR-FTIR) without increase of lipid disorder and change in the tilt between the normal and the germanium surface (also determined by ATR-FTIR). All together, differences of ciprofloxacin as compared to moxifloxacin in their interactions with lipids could explain differences in their cellular accumulation and susceptibility to efflux transporters
Influence of phenological barriers and habitat differentiation on the population genetic structure of the balearic endemic Rhamnus ludovici-salvatoris Chodat and R. alaternus L
[EN] Rhamnus ludovici-salvatoris, endemic to the Gymnesian Islands, coexists with the related and widespread R. alaternus in Mallorca and Menorca. In both species, the population genetic structure using RAPD, and flowering during a 3-year period to check for possible phenological barriers, were analyzed. Rhamnus ludovici-salvatoris showed lower genetic diversity and stronger population structure than R. alaternus, the Cabrera population being less diverse and the most differentiated. Rhamnus ludovici-salvatoris flowered one month later, although flowering of both species coincided sporadically. These congeners seem to have diverged through isolation by time and differentiation in habitat. The population genetic structure of R. ludovici-salvatoris could mainly be due to the existence of small populations on the one hand, and a gene flow caused by rare hybridization events on the other, which may also explain the presence of morphologically intermediate individuals in Menorca. The conservation of R. ludovici-salvatoris populations may include population reinforcements and other in situ interventions.Ferriol Molina, M.; Llorens García, L.; Gil, L.; Boira Tortajada, H. (2009). Influence of phenological barriers and habitat differentiation on the population genetic structure of the balearic endemic Rhamnus ludovici-salvatoris Chodat and R. alaternus L. Plant Systematics and Evolution. 277(1-2):105-116. doi:10.1007/s00606-008-0110-3S1051162771-2Affre L, Thompson JD, Debussche M (1997) Genetic structure of continental and island populations of the Mediterranean endemic Cyclamen balearicum (Primulaceae). Amer J Bot 84(4): 437–451BOIB (2005) Decreto 75/2005. BOIB 106: 29–32Bolmgren K, Oxelman B (2004) Generic limits in Rhamnus L. s.l. (Rhamnaceae) inferred from nuclear and chloroplast DNA sequence phylogenies. Taxon 53(2):383–390Bolòs O, Molinier R (1958) Recherches phytosociologiques dans l’île de Majorque. Collectanea Botanica 34:699–865Cardona MA (1979) Consideracions sobre l’endemisme i l’origen de la flora de las Illes Balears. Butlletí del Institut Catalá de Historia Natural 44 (Sec. Bot. 3):7–15Cardona MA, Contandriopoulos J (1979) Endemism and evolution in the islands of the Western Mediterranean. In: Bramwell D (ed) Plants and islands. Academic Press, London, pp 133–169Chodat L (1924) Contributions à la Géo-Botanique de Majorque. PhD Thesis, Université de Genève—Institut de Botanique, SwitzerlandCollins D, Mill RR, Moller M (2003) Species separation of Taxus baccata, T. canadensis, and T. cuspidata (Taxaceae) and origins of their reputed hybrids inferred from RAPD and cpDNA data. Amer J Bot 90(2):175–182Cronk QCB (1997) Islands: stability, diversity, conservation. Biodivers Conserv 6(3):477–493Doyle JJ, Doyle JL (1990) Isolation of plant DNA from fresh tissue. Focus 12:13–15Ducarme V, Wesselingh RA (2005) Detecting hybridization in mixed populations of Rhinanthus minor and Rhinanthus angustifolius. Folia Geobot 40(2/3):151–161Englishloeb GM, Karban R (1992) Consequences of variation in flowering phenology for seed head herbivory and reproductive success in Erigeron glaucus (Compositae). Oecologia 89:588–595Gautier F, Caluzon G, Suk JP, Violanti D (1994) Age et durée de la crise de salinité Messinienne. Comptes Rendus de l’Académie des Sciences de Paris 318:1103–1109Gerard PR, Fernandez-Manjarres JF, Frascaria-Lacoste N (2006) Temporal cline in a hybrid zone population between Fraxinus excelsior L. and Fraxinus angustifolia Vahl. Molec Ecol 15:3655–3667Gil L, Llorens L, Tébar FJ, Costa M (1995) La vegetación de la isla de Cabrera. In: Guía de la excursión geobotánica de las XV Jornadas de Fitosociología. Datos sobre la vegetación de Cabrera. Palma de Mallorca: Universitat de les Illes Balears, pp 51–77Gulías J, Flexas J, Abadía A, Medrano H (2002) Photosynthetic responses to water deficit in six Mediterranean sclerophyll species: possible factors explaining the declining distribution of Rhamnus ludovici-salvatoris, and endemic Balearic species. Tree Physiol 22:687–697Gulías J, Traveset A, Riera N, Mus M (2004) Critical stages in the recruitment process of Rhamnus alaternus L. Ann Bot 93:723–731Gustafsson S, Sjögren-Gulve P (2002) Genetic diversity in the rare orchid, Gymnadenia odoratissima and a comparison with the more common congener, G. conopsea. Conserv Genet 3:225–234Gustafsson S (2003) Population genetic analyses in the orchid genus Gymnadenia—a conservation genetic perspective. PhD Thesis, Uppsala University, SwedenGustafsson S, Lönn M (2003) Genetic differentiation and habitat preference of flowering-time variants within Gymnadenia conopsea. Heredity 91:284–292Harris W (1996) Genecological aspects of flowering patterns of populations of Kunzea ericoides and K. sinclairii (Myrtaceae). New Zealand J Bot 34:333–354Hendry AP, Dray T (2005) Population structure attributable to reproductive time: isolation by time and adaptation by time. Molec Ecol 14:901–916Hosokawa K, Minami M, Kawahara K, Nakamura I, Shibata T (2000) Discrimination among three species of medicinal Scutellaria plants using RAPD markers. Pl Med 66:270–272Huang Z, Liu L, Zhou T, Ju B (2005) Effects of environmental factors on the population genetic structure in chukar partridge (Alectoris chukar). J Arid Environ 62:427–434Juan A, Crespo MB, Cowan RS, Lexer C, Fay F (2004) Patterns of variability and gene flow in Medicago citrina, an endangered endemic of islands in the western Mediterranean, as revealed by amplified fragment length polymorphism (AFLP). Molec Ecol 13:2679–2690Krijgsman W, Hilgen FJ, Raffi I, Sierro FJ, Wilson DS (1999) Chronology, causes and progression of the Messinian salinity crisis. Nature 400:652–655Lamont BB, He T, Enright NJ, Krauss SL, Miller BP (2003) Anthropogenic disturbance promotes hybridization between Banksia species by altering their biology. J Evol Biol 16:551–557Lennartsson T (1997) Seasonal differentiation—a conservative reproductive barrier in two grassland Gentianella (Gentianaceae) species. Pl Syst Evol 208:45–69Martinez-Solis I, Iranzo J, Estrelles E, Ibars AM (1993) Leaf domatia in the section Alaternus (Miller) DC. of the genus Rhamnus (Rhamnaceae). Bot J Linn Soc 112:311–318McIntosh ME (2002) Flowering phenology and reproductive output in two sister species of Ferocactus (Cactaceae). Pl Ecol 159:1–13Nei M (1973) Analysis of gene diversity in subdivided populations. Proc Natl Acad Sci USA 70:3321–3323Nei M (1978) Estimation of average heterozigosity and genetic distance from a small number of individuals. Genetics 89:583–590Nei M, Li W (1979) Mathematical model for studying genetic variation in terms of restriction endonucleases. Proc Natl Acad Sci USA 79:5269–5273Nybom H, Bartish IV (2000) Effects of life history traits and sampling strategies on genetic diversity estimates obtained with RAPD markers in plants. Perspect Pl Ecol Evol Syst 3(2):93–114Oostermeijer JGB, Luijten SH, Ellis-Adam AC, den Nijs JCM (2002) Future prospects for the rare, late-flowering Gentianella germanica and Gentianopsis ciliata in Dutch nutrient-poor calcareous grasslands. Biol Conserv 104:339–350Pease CM, Lande R, Bull JJ (1989) A model of population growth, dispersal and evolution in a changing environment. Ecology 70(6):1657–1664Perron M, Gordon AG, Bousquet J (1995) Species-specific RAPD fingerprints for the closely related Picea mariana and P. rubens. Theor Appl Genet 91:142–149Pierce S, Ceriani RM, Villa M, Cerabolini B (2006) Quantifying relative extinction risks and targeting intervention for the orchid flora of a natural park in the European prealps. Conserv Biol 20(6):1804–1810Richardson JE, Fay MF, Cronk QCB, Bowman D, Chase MW (2000) A phylogenetic analysis of Rhamnaceae using rbcL and trnL-F plastid DNA sequences. Amer J Bot 87(9):1309–1324Roselló JA, Sáez L (2000) Index Balearicum: an annotated check-list of the vascular plants described from the Balearic Islands. Collect Bot 25(1):3–203Roselló JA, Cebrián MC, Mayol M (2002) Testing taxonomic and biogeographical relationships in a narrow mediterranean endemic complex (Hippocrepis balearica) using RAPD markers. Ann Bot 89:321–327Sales E, Nebauer SG, Mus M, Segura J (2001) Population genetic study in the Balearic plant species Digitalis minor (Scrophulariaceae) using RAPD markers. Amer J Bot 88(10):1750–1759Sherwin WB, Moritz C (2000) Managing and monitoring genetic erosion. In: Young AG, Clarke GM (eds) Genetics, demography and viability of fragmented populations. Cambridge University Press, Cambridge, pp 9–34Sneath PHA, Sokal RR (1973) Numerical taxonomy. Freeman and Co., San FranciscoTraveset A, Gulías J, Riera N, Mus M (2003) Transition probabilities from pollination to establishment in a rare dioecious shrub species (Rhamnus ludovici-salvatoris) in two habitats. J Ecol 91:427–437Tutin TG, Heywood VH, Burges NA, Valentine DH, Walters SM, Webb DA (eds) (2001) Flora Europaea, vol 2. Rosaceae to Umbelliferae. Cambridge University Press, CambridgeWright S (1931) Evolution in Mendelian populations. Genetics 16:97–159Zimmerman M (1980a) Reproduction in Polemonium: pre-dispersal seed predation. Ecology 61:502–506Zimmerman M (1980b) Reproduction in Polemonium: competition for pollinators. Ecology 61:497–50
The Enigma of Soil Animal Species Diversity Revisited: The Role of Small-Scale Heterogeneity
Peer reviewedPublisher PD
Conservation genetics of the annual hemiparasitic plant Melampyrum sylvaticum (Orobanchaceae) in the UK and Scandinavia
Melampyrum sylvaticum is an endangered annual hemiparasitic plant that is found in only 19 small and isolated populations in the United Kingdom (UK). To evaluate the genetic consequences of this patchy distribution we compared levels of diversity, inbreeding and differentiation from ten populations from the UK with eight relatively large populations from Sweden and Norway where the species is more continuously distributed. We demonstrate that in both the UK and Scandinavia, the species is highly inbreeding (global F IS = 0.899). Levels of population differentiation were high (F’ST = 0.892) and significantly higher amongst UK populations (F’ST = 0.949) than Scandinavian populations (F’ST = 0.762; P < 0.01). The isolated populations in the UK have, on average, lower genetic diversity (allelic richness, proportion of loci that are polymorphic, gene diversity) than Scandinavian populations, and this diversity difference is associated with the smaller census size and population area of UK populations. From a conservation perspective, the naturally inbreeding nature of the species may buffer the species against immediate effects of inbreeding depression, but the markedly lower levels of genetic diversity in UK populations may represent a genetic constraint to evolutionary change. In addition, the high levels of population differentiation suggest that gene flow among populations will not be effective at replenishing lost variation. We thus recommend supporting in situ conservation management with ex situ populations and human-mediated seed dispersal among selected populations in the UK
Juvenile “black teatfish” in Maldives
Juvenile holothurians remain poorly understood globally. This is likely the result of two main factors: they are rarely observed, and they are difficult to identify once found (given the changes in colouration of the body wall and ossicle morphology during growth). We report on the discovery of four holothurian individuals that have been provisionally described as juvenile “black teatfish”, Holothuria cf. nobilis. These juveniles were observed in August 2015
within the patch reef off Vavvaru on Lhaviyani Atoll in Maldives
An overview on wavelet multi-resolution decomposition compared with traditional frequency domain filtering for continuous gravity data denoising
Continuous gravity recordings in volcanic area could play a fundamental role in the
monitoring of active volcanoes and in the prediction of eruptive events too. This geophysical
methodology is utilized, on active volcanoes, in order to detect mass changes linked to magma
transfer processes and, thus, to recognize forerunners to paroxysmal volcanic events. Spring
gravimeters are still the most utilized instruments for microgravity studies because of their
relatively low cost and small size, which make them easy to transport and install. Continuous
gravity measurements are now increasingly performed at sites very close to active craters, where
there is the greatest opportunity to detect significant gravity changes due to a volcanic activity.
Unfortunately, spring gravity meters show a strong influence of meteorological parameters (i.e.
pressure, temperature and humidity), especially in the adverse environmental conditions usually
encountered at such places. As the gravity changes due to the volcanic activity are very small
compared to other geophysical or instrumental effects we need a new mathematical tool to get
reliable gravity residuals susceptible to reflect the volcanic effect. In the following we present and
discuss a preliminary work about the confrontation between the traditional filtering methodology
and the Wavelet transform. The overall results show that the performance of the wavelet-based filter
seems better than the Fourier one. Moreover, the possibility of getting a multi-resolution analysis
and study local features of the signal in the time domain makes the proposed methodology a
valuable tool for gravity data processing.Submittedope
Oribatid mites (Acari, Oribatida) in selected caves of the Kraków-Wieluń Upland (southern Poland)
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