Search results for "Systematics"

Origin and distribution of suspended organic matter as inferred from carbon isotope composition in a Mediterranean semi-enclosed marine system

1999

The origin and distribution of suspended organic matter, the trophic features and the stable carbon isotopic composition of particulate organic carbon (POC) were studied monthly in a Western Mediterranean semi-enclosed basin. Sampling stations were selected as a function of wind-exposure and the degree of vegetation cover and then compared with an adjacent unvegetated site. The predominant vegetation was seagrass (Posidonia oceanica and Cymodocea nodosa) and Caulerpa prolifera. Water samples were analyzed for total suspended matter (inorganic and organic fractions), photosynthetic pigments (chlorophyll-a and phaeopigments), dissolved organic carbon, particulate organic carbon and their isot…

Sources of carbon and dietary habits of new Lessepsian entry Brachidontes pharaonis (Bivalvia, Mytilidae) in the western Mediterranean

2003

The sources of carbon and the dietary habits of Brachidontes pharaonis (Mollusca, Bivalvia), a new Lessepsian entry in the western Mediterranean, living in a cooling vat of a saltworks system in western Sicily (MED), were assessed by estimating throughout a season the relative abundance of a stable carbon isotope (δ13C) in particulate organic matter (POM), sedimentary organic matter (SOM), primary organic matter sources (seagrasses, sand microflora, macroalgae), Brachidontes pharaonis and its biodeposition material. In the saltworks the most enriched primary food source potentially fuelling the saltworks food web was Cymodocea nodosa (seasonal average -7.9±0.6‰), Laurencia papillosa and Cys…

�ber den 3,5-Tage-Effekt bei der R�ntgenbestrahlung von H�hnerembryonen

1962

In order to observe the development and vitality of chicken embryos before and after irradiation without halting the growth, the eggs were provided with plate glass windows. The results showed that at irradiation doses of 800 to 2400 r, the survival of the 13-somite stage embryos drops abruptly from 98 to 6%. These results had good reproducibility. This sharp decrease in the percentage survival corresponds to the 3.5-day effect in mice. In addition to the reduced survival, a dose-dependent retardation of the morphological development was also observed. (J.S.R.)

MARTX ofVibrio vulnificusbiotype 2 is a virulence and survival factor

2012

Vibrio vulnificus biotype 2 is a polyphyletic group whose virulence for fish relies on a plasmid. This plasmid contains an rtxA gene duplicated in the small chromosome that encodes a MARTX (Multifunctional, Autoprocessing Repeats-in-Toxin) unique within the species in domain structure (MARTX type III). To discover the role of this toxin in the fitness of this biotype in the fish-farming environment, single- and double-knockout mutants were isolated from a zoonotic strain and analysed in a series of in vivo and in vitro experiments with eel, fish cell lines and amoebae isolated from gills. Mice, murine and human cell lines were also assayed for comparative purposes. The results suggest that …

Determination of trace elements in water by metal chelate capillary gas chromatography

1981

Typification of the names Anethum pusillum and Meum segetum (Apiaceae)

2022

Recent works (Jimenez-Mejias & Vargas 2015, Frankiewicz et al. 2021) have improved our knowledge about systematics and phylogeny of the Apiaceae: in detail, the Authors suggested the opportunity to merge several genera within Anethum Linnaeus (1753: 263), namely: Foeniculum Miller (1754: [513]), Ridolfia Moris (1841: 43), Pseudoridolfia Reduron, Mathez & S. R. Downie in Reduron et al. (2009: 496), and Schoenoselinum Jimenez-Mejias & Vargas (2015: 75). In this framework, we think that it is important to typify the names Anethum pusillum All. (Allioni 1773: 28) and Meum segetum Guss. (Gussone 1827: 346), both belonging to this “Anethum alliance” (as defined by Jimenez-Mejias &…

The Centaurea parlatoris complex (Asteraceae): taxonomic checklist and typifications

2021

A taxonomic account of the Centaurea parlatoris complex (Asteraceae), endemic to Sicily, is presented. This complex includes six taxa, three described in the 19th century (C. parlatoris, C. parlatoris var. tomentosa and C. parlatoris var. virescens) and three recently described (C. sicana, C. giardinae and C. heywoodiana). Starting from the designation of the types for the oldest plant names that have not been typified yet, taxonomic considerations are formulated and C. parlatoris var. virescens is elevated to the rank of species. An identification key and a distribution map complete this account.

Risk exposure to vibration and noise in the use of agricultural track-laying tractors.

2016

Human exposure to mechanical vibration may represent a significant risk factor for exposed workers in the agricultural sector. Also, noise in agriculture is one of the risk factors to be taken into account in the evaluation of workers’ health and safety. One of the major sources of discomfort for the workers operating a tractors is the noise to which they are exposed during work. The aim of this study was to evaluate the risk of exposure to whole-body vibration for the operator driving track-laying tractors in vineyard orchard and the noise level. The experimental tests were performed with six different track-laying tractors coupled with the same rototilling machine. The results showed that…

Antifeedant activity of neo-clerodane diterpenoids from Teucrium arduini

2002

Honeybees can recognise images of complex natural scenes for use as potential landmarks

2008

SUMMARY The ability to navigate long distances to find rewarding flowers and return home is a key factor in the survival of honeybees (Apis mellifera). To reliably perform this task, bees combine both odometric and landmark cues,which potentially creates a dilemma since environments rich in odometric cues might be poor in salient landmark cues, and vice versa. In the present study, honeybees were provided with differential conditioning to images of complex natural scenes, in order to determine if they could reliably learn to discriminate between very similar scenes, and to recognise a learnt scene from a novel distractor scene. Choices made by individual bees were modelled with signal detec…