Search results for "Lene"
showing 10 items of 4480 documents
Alarmist by bad design: Strongly popularized unsubstantiated claims undermine credibility of conservation science
2019
“Unless we change our ways of producing food, insects as a whole will go down the path of extinction in a few decades.” or “Our work reveals dramatic rates of decline that may lead to the extinction of 40% of the world's insect species over the next few decades.” These are verbatim conclusions of the recent paper by Sánchez-Bayoa and Wyckhuys (2019) in Biological Conservation. Because of fundamental methodological flaws, their conclusions are unsubstantiated. Like noted by The Guardian, the conclusions of the paper were set out in unusually forceful terms for a peer-reviewed scientific paper. The current case…
Brūklenes Vaccinium vitis-idaea (L.) sastopamības, seguma un vecumstruktūras salīdzinājums dažāda vecuma sila audzēs Ropažu un Upmales līdzenumos
2019
Brūklenes ir bieži sastopamas visā Latvijas teritorijā. Tāpēc svarīgi izpētīt veģetācijas, audzes vecuma un biezības ietekmējošo faktoru saistību ar salīdzinoši ekoloģiski plastisko brūkleni. Lai noskaidrotu kā dažāda vecuma sila audzēs mainās brūkleņu sastopamība, segums un vecums, 2018. gada augustā un septembrī divās teritorijās Latvijā – Ropažu un Upmales līdzenumā, ierīkoti astoņi objekti 24 audzēs. Pētījuma praktiskā daļa izstrādāta tādā meža tipā kā sils. Analizētas dažādas vecuma audzes. Lai raksturotu brūklenes sastopamību un segumu, mežaudzēs ierīkoja transektes ar sešiem 1x1 m parauglaukumiem. Katrā no sešiem 1x1 m parauglaukumiem veica veģetācijas raksturojumu, ievāca trīs brūkl…
Kritiskā flikera fūzijas frekvence kā redzes noguruma indikators
2015
Bakalaura darbs uzrakstīts latviešu valodā, uz 32 lapaspusēm, satur 20 attēlus, 4 tabulas, atsaucas uz 17literatūras avotiem un ietver 2 pielikumus. Mērķis: noteikt kritiskās flikera fūzijas frekvences robežas izmaiņas pirms un pēc redzes noguruma. Metode: Eksperimenta dalībniekiem tika pārbaudīta kritiskās flikera fūzijas frekvences slieksnis pirms un pēc redzes noguruma. Nogurdināšanas pamatā ir darbs ar datoru divu stundu garumā. Rezultāti: KFF frekvence samazinās pēc redzes noguruma uzdevuma, labāki rezultāti tiek uzrādīti pie zaļās krāsas stimula. KFF frekvences pamanīšanas sliekšņi mērot ar zaļas krāsas stimuluir 36,30 Hz, ar sarkanas krāsas stimulu 25,89 Hz, taču zilas krāsas stimulu…
Volumes of aqueous block copolymers based on poly(propylene oxides) and poly(ethylene oxides) in a large temperature range: A quantitative description
2006
The focus of this paper was on a quantitative comprehension of temperature effect on the volumes of aqueous di-block and triblock copolymers, based on propylene oxide (PO) and ethylene oxide (EO) units. To this purpose, literature data dealing with (EO316PO94 + water) and (EO13PO30EO13 + water) mixtures were analyzed. The volume vs. temperature trends were rationalized on the basis of the (unimers + aggregate) equilibrium by taking into account the temperature effect on both the partial molar volumes of the unimeric and the aggregated copolymer as well as the equilibrium constant of micellization. The analysis extended to the expansibility allowed to quantify the contribution for the shift …
Indian Yellow and Titanium White : A Material-centred Perspective on the Pigments Used by Artists Helene Schjerfbeck and Akseli Gallen-Kallela in the…
2022
This article presents the results of material studies focused on identifying and comparing the contents of the pigment palettes of two notable Finnish painters, Helene Schjerfbeck (1862–1946) and Akseli Gallen-Kallela (1865–1931). The research methods used comprise energydispersive X-ray fluorescence spectrometry (EDXRF) and polarised light microscopy (PLM). In addition, certain pigments have been identified in colour areas of the works using specular reflection FT-infrared spectrometry (FTIR) and Raman spectrometry. To support the results gathered using scientific analytical methods, archival research has been conducted in order to find notes and references to the pigments made by the arti…
Evaluation of biocidal potential of some plant species from the Mediterranean wild flora
Chemical Composition of the Essential Oil of Bupleurum Fontanesii (Apiaceae) Growing Wild in Sicily and its Activity on Microorganisms Affecting Hist…
2016
Hydrodistillation of the flowers (BpFl) of and fruits (BpFr) of Bupleurum fontanesii Guss. ex Caruel gave two oils that were analyzed by GC and GC-MS. The main components were α-elemol (16.7%), caryophyllene oxide (16.4%) and heptacosane (15.9%) in BpFl, and spathulenol (16.8%), caryophylladienol I (13.2%) and α-elemol (12.8%) in BpFr. A good antimicrobial activity against several microorganisms, including Bacillus subtilis, Staphylococcus aureus, Fusarium oxysporum and Aspergillus niger, all infesting historical art craft, was also determined.
EVALUATION OF BIODEGRADABILITY ON POLYSPARTAMIDE-POLYLACTIC ACID BASED NANOPARTICLES BY CHEMICAL HYDROLYSIS STUDIES POLYMER DEGRADATION AND STABILITY
2015
Here, the synthesis of two graft copolymers based on α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA) and poly(lactic acid) (PLA), the O-(2-aminoethyl)-O′-galactosyl polyethylene glycol (GAL-PEG-NH2) or the methoxypolyethylene glycol amine (H2N-PEG-OCH3) is described. Starting from the obtained PHEA-PLA-PEG-GAL and PHEA-PLA-PEG copolymers, polymeric nanoparticles were prepared by high pressure homogenization–solvent evaporation method. To demonstrate their biodegradability as a function of the matrix composition, a chemical stability study was carried out until 21 days by incubating systems in two media mimicking physiological compartments (pH 7.4 and pH 5.5). The degradability of both nan…