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91.
Canwei Xia Jiayu Liu Per Alström Qiao Wu Yanyun Zhang 《Ethology : formerly Zeitschrift fur Tierpsychologie》2013,119(8):653-661
Soft songs have been detected in many songbirds, but in most species, research on soft songs has lagged behind studies of broadcast songs. In this study, we describe the acoustic features of a soft song in the brownish‐flanked bush warbler Cettia fortipes. Compared with the broadcast song, the warbler's soft song was characterized by a lower minimum frequency and longer duration, and it had a higher proportion of rapid frequency modulation notes. Using playback experiments, some in combination with mounted specimens, we found different responses to soft and broadcast songs, and we found that soft song can predict aggressive escalation (attack). We conclude that the soft song is an aggressive signal in this species. 相似文献
92.
Although there are generalized conceptual models that predict how above and belowground biomass increase during secondary succession after abandonment from agriculture, there are few data to test these models for fine roots (defined as ≤2 mm diameter) in tropical forests. We measured live and dead fine roots (0–10 cm depth) in 18 plots of regenerating tropical dry forest in Costa Rica that varied in age from 5 to 60 yrs, as well as in soil properties. We predicted that both stand age and soil fertility would affect fine roots, with greater values in older forests on low fertility soils. Across two sampling dates and locations, live fine roots varied from 0.35 to 3.53 Mg/ha and dead roots varied from 0.15 to 0.93 Mg/ha. Surprisingly, there was little evidence that surface fine roots varied between sampling dates or in relation to stand age. By contrast, total, live, and dead fine roots averaged across sampling dates within plots were negatively correlated with a multivariate index of soil fertility (Pearson correlations coefficients were ?0.64, ?0.58, and ?0.68, respectively; P < 0.01) and other individual edaphic variables including pH, silt, calcium, magnesium, nitrogen, and phosphorus. These results suggest that soil fertility is a more important determinant of fine roots than forest age in tropical dry forests in Costa Rica, and that one‐way these plant communities respond to low soil fertility is by increasing fine roots. Thus, simple conceptual models of forest responses to abandonment from agriculture may not be appropriate for surface fine roots. 相似文献
93.
Irene Stranden Løvdal Per Einar Granum Jan Thomas Rosnes Trond Løvdal 《Antonie van Leeuwenhoek》2013,103(3):693-700
The time/temperature profiles experienced by spores on the track from their natural sporulation environment to consumable food products may be highly diverse. Temperature has been documented as an important factor that may activate spores, i.e. potentiates spores to germinate. There is, however, limited knowledge about the relationship between the expected temperature history and the subsequent germination characteristics of bacterial spores. We show here that the germination rate of five different Bacillus spore populations, represented by strains of Bacillus cereus, Bacillus weihenstephanensis, Bacillus pumilus, Bacillus licheniformis and Bacillus subtilis could be increased following 1 week storage at moderately elevated temperatures, 30–33 °C, compared to spores stored at 3–8 °C. The results imply that spores contamination routes to foods, specifically the temperature history, could be highly relevant data in predictive modeling of food spoilage and safety. Activation at these moderately elevated temperatures may be a native form of spore activation in their natural habitats, knowledge that also could be useful in development of decontamination strategies for mildly heated foods. 相似文献
94.
Semicontinuous registration of the normal airborne bacteria flora during a one-year period was carried out at an inland and a coastal station near Stockholm. The sampling apparatus were FOA-slitsamplers that work on the impaction principle with a moving solid agar medium as collecting surface. At both localities meteorological variables were also recorded. The concentration of airborne bacteria ranged for the inland station from 0-500 bacteria/m3 with an average of 51 bacteria/m3 and for the coastal station from 0-250 bacteria/m3 with an average of 16 bacteria/m3. The diurnal pattern of variation varies with the time of year but there is a statistical difference between the day-average and night-average for the inland station but not for the coastal station. In the material studied the relative humidity followed by the wind velocity were factors of importance for the variation in the number of viable airborne bacteria. 相似文献
95.
Xifu Liang Gunnar Grue-Sørensen Kristoffer Månsson Per Vedsø Anke Soor Martin Stahlhut Malene Bertelsen Karen Margrethe Engell Thomas Högberg 《Bioorganic & medicinal chemistry letters》2013,23(20):5624-5629
Ingenol mebutate is the active ingredient in Picato® a new drug for the treatment of actinic keratosis. A number of derivatives related to ingenol mebutate were prepared by chemical synthesis from ingenol with the purpose of investigating the SAR and potency in assays relating to pro-inflammatory effects (induction of PMN oxidative burst and keratinocyte cytokine release), the potential of cell death induction, as well as the chemical stability. By modifications of the ingenol scaffold several prerequisites for activity were identified. The chemical stability of the compounds could be linked to an acyl migration mechanism. We were able to find analogues of ingenol mebutate with comparable in vitro properties. Some key features for potent and more stable ingenol derivatives have been identified. 相似文献
96.
Martin Mendez Thomas A. Jefferson Sergios‐Orestis Kolokotronis Michael Krützen Guido J. Parra Tim Collins Giana Minton Robert Baldwin Per Berggren Anna Särnblad Omar A. Amir Vic M. Peddemors Leszek Karczmarski Almeida Guissamulo Brian Smith Dipani Sutaria George Amato Howard C. Rosenbaum 《Molecular ecology》2013,22(23):5936-5948
The conservation of humpback dolphins, distributed in coastal waters of the Indo‐West Pacific and eastern Atlantic Oceans, has been hindered by a lack of understanding about the number of species in the genus (Sousa) and their population structure. To address this issue, we present a combined analysis of genetic and morphologic data collected from beach‐cast, remote‐biopsied and museum specimens from throughout the known Sousa range. We extracted genetic sequence data from 235 samples from extant populations and explored the mitochondrial control region and four nuclear introns through phylogenetic, population‐level and population aggregation frameworks. In addition, 180 cranial specimens from the same geographical regions allowed comparisons of 24 morphological characters through multivariate analyses. The genetic and morphological data showed significant and concordant patterns of geographical segregation, which are typical for the kind of demographic isolation displayed by species units, across the Sousa genus distribution range. Based on our combined genetic and morphological analyses, there is convincing evidence for at least four species within the genus (S. teuszii in the Atlantic off West Africa, S. plumbea in the central and western Indian Ocean, S. chinensis in the eastern Indian and West Pacific Oceans, and a new as‐yet‐unnamed species off northern Australia). 相似文献
97.
Eva Nordlund Anders Düker Stefan Karlsson Anna Ledin Per Sandén Karin Sundblad 《Chemical Speciation and Bioavailability》2013,25(2):57-63
ABSTRACTFormation of gel-like surface sediments has been observed during spring and autumn in small watersheds in boreal areas with pH <5.7 and concentrations of humic substances above 3 mg L?1. This structure efficiently accumulates dissolved, colloidal and particulate constituents. The gel consists of ferric (hydr)oxides and fulvic acid and has high viable counts of bacteria (notably Gallionella spp.) as well as fungal hyphae. The solid/solution distribution (log Kd; l kg?1) for trace metals (Cd, Cu, Pb, V, Zn) ranges from 4 to 6.5 which indicate an efficient accumulation during periods with gel. The concentrations of adsorbable organic halogens in the gel were not different from forest soils in general. 相似文献
98.
Sophie Sanchez Vincent Dupret Paul Tafforeau Katherine M. Trinajstic Bettina Ryll Pierre-Jean Gouttenoire Lovisa Wretman Louise Zylberberg Fran?oise Peyrin Per E. Ahlberg 《PloS one》2013,8(2)
Background
Firm attachments binding muscles to skeleton are crucial mechanical components of the vertebrate body. These attachments (entheses) are complex three-dimensional structures, containing distinctive arrangements of cells and fibre systems embedded in the bone, which can be modified during ontogeny. Until recently it has only been possible to obtain 2D surface and thin section images of entheses, leaving their 3D histology largely unstudied except by extrapolation from 2D data. Entheses are frequently preserved in fossil bones, but sectioning is inappropriate for rare or unique fossil material.Methodology/Principal Findings
Here we present the first non-destructive 3D investigation, by propagation phase contrast synchrotron microtomography (PPC-SRµCT), of enthesis histology in extant and fossil vertebrates. We are able to identify entheses in the humerus of the salamander Desmognathus from the organization of bone-cell lacunae and extrinsic fibres. Statistical analysis of the lacunae differentiates types of attachments, and the orientation of the fibres, reflect the approximate alignment of the muscle. Similar histological structures, including ontogenetically related pattern changes, are perfectly preserved in two 380 million year old fossil vertebrates, the placoderm Compagopiscis croucheri and the sarcopterygian fish Eusthenopteron foordi.Conclusions/Significance
We are able to determine the position of entheses in fossil vertebrates, the approximate orientation of the attached muscles, and aspects of their ontogenetic histories, from PPC-SRµCT data. Sub-micron microtomography thus provides a powerful tool for studying the structure, development, evolution and palaeobiology of muscle attachments. 相似文献99.
Alcohol consumption and alcohol problems after bariatric surgery in the swedish obese subjects study
100.