Search results for "transe"

Jūras kraukļu (Phalacrocorax carbo sinensis) ietekme uz Ežezera Siena salas vidi

2015

Jūras kraukļi (Phalacrocorax carbo sinensis) jeb kormorāni ir tipiski kolonijās dzīvojoši ūdensputni. Visbiežāk par mājvietu sev rod ezeru salas, kā rezultātā kolonijas nepārtrauktās ietekmes dēļ notiek pastiprināti traucējumi ekosistēmas darbībai un attīstībai. Kormorānu skaitam gan pasaulē kopumā, gan Latvijā ir tendence palielināties, kā rezultātā ietekmēto teritoriju skaits un to radītās sekas pieaug. Tiek nomākta, citos gadījumos arī iznīcināta - veģetācija, augsne tiek piesātināta ar mēslojumu un līdz ar to - papildus ķīmiskajiem savienojumiem, kas maina ne tikai tajā notiekušos procesus, bet arī notiek elementu un savienojumu migrācija uz gruntsūdeņiem, kā arī blakus esošajām ekosist…

Spatial models for monitoring the spatio-temporal evolution of ashes after fire-a case study of a burnt grassland in Lithuania

2013

Ash thickness is a key variable in the protection of soil against erosion agents after planned and unplanned fires. Ash thickness measurements were conducted along two transects (flat and sloping areas) following a grided experimental design. In order to interpolate data with accuracy and identify the techniques with the least bias, several interpolation methods were tested in the grided plot. Overall, the fire had a low severity. However, the fire significantly reduced the ground cover, especially on sloping areas, owing to the higher fire severity and/or less biomass previous to the fire. Ash thickness depended on fire severity and was thin where fire severity was higher and thicker in lo…

Recent changes in measured wind in the NE Atlantic and variability of correlation with NAO

2010

The paper deals with wind measurements, recorded since the 1950s, at twelve meteorological stations along a transect near the westernmost European border, between 64° and 44° N. Extreme wind speed tends to decrease sharply near the northern boundary (at Reykjavick), near the middle of the study area (at Shannon and Valentia) and near the southern boundary (at Brest and Cap Ferret), to increase at Thorshavn, with less significant trends at the other stations. Average wind speeds confirm the above tendencies, with an additional increasing speed at Lerwick, Kirkwall, Malin Head, Belle-Ile and Cap Ferret. To compare changes in wind activity, the data have been subdivided into three periods: unt…

Millennial-scale terrestrial ecosystem responses to Upper Pleistocene climatic changes: 4D-reconstruction of the Schwalbenberg Loess-Palaeosol-Sequen…

2021

Abstract Loess-Palaeosol-Sequences (LPS) in the Central European region provide outstanding terrestrial polygenetic and multiphase archives responding to past climate and environments over various spatial and temporal scales. As yet, however, the geomorphological and pedogenic processes involved in LPS formation, and their interplay with changes in ecological conditions, impede robust correlation with other palaeoenvironmental archives. The Schwalbenberg LPS, which drape a hillslope in the Middle Rhine Valley in western Central Europe, provide unique high-resolution records highly suitable for investigating the processes involved in their formation and the relationship to climatic influence…

Stand structure and spatial pattern of regeneration of Pinus sylvestris in a natural treed mire in Latvia

2009

We examined the regeneration patterns of Pinus sylvestris L. in a natural treed mire in the hemiboreal zone in Latvia. Data on tree stem age and size was collected in 207 fine-scale plots (10 m) and 4 medium-scale plots (400 m). Size structure of living and dead trees was also estimated on transects 180-m and 250-m length and 10-m width. In addition, the vegetation was described in 1-m plots to determine preferred microsites for P. sylvestris establishment. Pinus sylvestris showed continuous regeneration by an inverse J-shaped age and size structure. Pulses of mortality induced by fire were also evident. Regeneration of P. sylvestris was mostly on Sphagnum magellanicam Brid. hummocks free o…

Activity and body orientation of Gallotia galloti in different habitats and daily times

2011

Abstract In lizards, site selection is related to the acquisition of resources such as refuges, mates or prey, but also to the exploitation of sites suitable for thermoregulation. The latter process may be affected by lizard posture and body axis orientation in relation to the sun as a way to optimize heat exchange throughout the day. Specific postures and body orientations could also contribute to more efficient signal transmission in social contexts. In this paper we analyze activity and body axis orientation of adult males and females of the lacertid Gallotia galloti in two localities of Tenerife with different structural habitats. We performed transects at both sampling localities in t…

A novel phosphorus–carbon bond formation by ring opening with diethyl phosphite of oxazolines derived from serine

2004

Abstract A new reaction of oxazolines derived from serine with diethyl phosphite leading to ring opening products with P–C bond formation is reported. This reaction, which proceeds under neutral conditions and without the use of any halogenated intermediate, results in a mixture of racemic α- and β-phosphono alanines in an approximate 1:2 ratio, with isolated yields up to 77%. The mechanism involves the rearrangement of the oxazoline into the corresponding α-benzamido acrylate, followed by addition of the diethyl phosphite to the double bond. Since no significant transesterification is observed, this method constitutes a simple route for α- and β-phosphono amino acids bearing suitable prote…

DUAL APPLICATION OF DIVALENT ION-ANCHORED CATALYST: BIODIESEL SYNTHESIS AND PHOTOCATALYTIC DEGRADATION OF CARBAMAZEPINE

2019

Improving lipase activity in solvent-free media by interfacial activation-based molecular bioimprinting

1997

Abstract Nine lipases of mammalian, fungal and bacterial origin and two different model reactions, direct esterification and transesterification (alcoholysis), have been used to probe the potential in solvent-free media of the recently reported strategy of interfacial activation-based molecular (bio)imprinting (IAMI) [Mingarro et al., Proc. Natl. Acad. Sci. USA , 92 (1995) 3308]. The results demonstrate that the imprinting treatment permits nonaqueous rate accelerations which are lipase-dependent and span in some cases up to higher than two orders of magnitude. For several lipases, the method allows conversion yields after short reaction times (in either of the model reactions assayed) whic…

Neutron Scattering of Poly(ethylene terephthalate)

1986

Through the use of deuterium labeling, small angle neutron scattering (SANS) has been found to be an extremely effective tool for elucidating the structure of polymer molecules in the condensed matter state. In this study, the molecular morphology of poly(ethylene terephthalate) (PET) has been determined under four different conditions: (1) in the glassy state, (2) in the semicrystalline state, (3) after cold-drawing, and (4) after undergoing partial transesterification.