285 research outputs found
Surface wax composition of wild and cultivated Northern berries
ArticleSurface wax of plants is the outer layer, which protects the plant from dehydration,
extreme temperatures, UV radiation and changes in the environment, as well as attacks from
moulds and bacteria. Studies of berry surface wax are of importance to understand metabolism
character (factors affecting wax layer composition in different berry species) as well as to increase
the shelf life of berries and increase the microbial resistance. The aim of this study was analysis
of surface wax composition of commercially grown 8 blueberry (Vaccinium corymbosum)
varieties, wild bilberry (Vaccinium myrtillus L.) and bog bilberry (Vaccinium uliginosum L.).
More than 80 different compounds were identified and quantified belonging to 9 groups of
compounds, namely, alkanes, phytosterols, alcohols, fatty acids, phenolic acids, ketones,
aldehydes, esters and tocopherols. Significant differences were found between blueberry
(Vaccinium corymbosum) and bog bilberry (Vaccinium uliginosum L.) surface wax composition.
Amongst studied berries differences were found in concentrations of triterpenes (up to 62% in
blueberries), and fatty acids (up to 26% in bilberries) identifying species related differences
influencing associated functional properties of berry wax (antimicrobial activity, stress caused by
environmental changes). Blueberry variety ‘Polaris’ had the highest amount of ursolic acid
(9.30 g 100 g
-1
), alpha-amyrin (11.07 g 100 g
-1
) and lupeol (10.2 g 100 g
-1
). Research on berry
surface wax composition could help reduce loss of commercially produced berries due to
environmental impacts or microbial attacks, prolonging shelf life and overall quality of fruits and
vegetables post-harvest
Sapropel processing approaches towards high added-value products
ArticleSapropel
is
an organic
sediment from
fresh
water bodies that is
widely
distributed
in
the northern regions of the w
orld. The distribution and
unique properties
of sapropel
make
it an
important
natural
resource that can
be used in agriculture
,
horticulture, forestry
and
farming
directly as obtained.
The aim of this study was to investigat
e the extraction possibilities of
sapropel and potential applications of its extracts. Humic substances constitute an important
ingredient of sapropel, and they
can be extracted by mild alkaline extraction. Humic substances
from peaty sapropel have signifi
cant differences in composition and properties, thus
demonstrating the impact of precursor biological materials on the properties of humic substances
formed in the humification process
UAV as a Reliable Wingman: A Flight Demonstration
In this brief, we present the results from a flight experiment demonstrating two significant advances in software enabled control: optimization-based control using real-time trajectory generation and logical programming environments for formal analysis of control software. Our demonstration platform consisted of a human-piloted F-15 jet flying together with an autonomous T-33 jet. We describe the behavior of the system in two scenarios. In the first, nominal state communications were present and the autonomous aircraft maintained formation as the human pilot flew maneuvers. In the second, we imposed the loss of high-rate communications and demonstrated an autonomous safe “lost wingman” procedure to increase separation and reacquire contact. The flight demonstration included both a nominal formation flight component and an execution of the lost wingman scenario
Physical-chemical properties and possible applications of clay minerals and humic acid composite materials
ArticlePollution caused by pharmaceuticals has become an increasingly serious issue,
therefore innovative and cost – effective methods of pharmaceutical’s removal must be studied.
Clay – humic acid composite materials can be considered as prospective and low cost sorbents
for contaminants. The aim of this study is to develop clay mineral and humic acid composite
materials and to characterise their possible applications. For this research, three types of clay
minerals (montmorillonite, kaolinite and bentonite) were modified with three types of humic
substances: technical humic acid from lignite, humic substances extracted from raised bog peat
and technical K humate from lignite. The sorption was characterised according to the chosen clay
mineral and humic acid type and concentration. The obtained material was characterised by
Fourier Transform Infrared spectroscopy and Scanning Electron microscopy. The composite
materials were tested for sorption of pharmaceuticals (chloropromazine hydrochloride). The
obtained results characterise clay mineral and humic acid composite materials’ possible
applications as sorbents for removal of pharmacologically active substances
Role of humic substances in agriculture and variability of their content in freshwater lake sapropel
ArticleThe term ‘humic substances’ (HS) refers to a general category of naturally occurring,
biogenic, heterogeneous organic substances. They create the most widespread natural organic
matter found in sediments, soils and waters. Organic carbon in soil (up to 70%) and peat (up to
90%) usually occurs in the form of HS. HS influence the formation process of fossil fuels, as well
as they are involved in the plant nutrition process, have an influence on availability and toxicity
of metallic and other elements. Furthermore, HS play a significant role in the global carbon
geochemical cycle. Properties and application efficiency of humus depend on the source of HS.
Freshwater sapropel is a huge reservoir of HS with superior biological activity, although their
total content is lower than in peat. The aim of this paper, firstly, was to present the information
about the options of HS in agriculture and their main effects on plant growth. Secondly,
determination and characterization of HS content in freshwater lake sapropel was performed as
sapropel nowadays becomes a popular natural organic-mineral fertilizer and soil conditioner.
Sapropel samples were derived from Lake Pilvelis, Lake Pilcines, Lake Vevers, Lake Liducis and
Lake Padelis situated in Eastern Latvia. Investigation of HS content in sapropel is significant for
the Baltic States and Northern Europe due to wide distribution and availability of sapropel in
freshwater bodies. That promotes a search for new ways of extraction methods and
bioeconomically effective utilization of this natural resource, obtainable in economically
significant amounts, with high opportunities of its use especially in agriculture. Contemporary
agriculture strongly desiderates in new products of high effectivity enhancing soil and crop
productivity and quality hand in hand with sustainable development and careful attitude to the
nature and surrounding environment, thus, one of the ways how it can be achieved is
understanding how, where and how much HS preparations can be applied
Properties of soil and peat humic substances from Latvia
ArticleThe acidity, elemental, functional and spectral (UV, fluorescence, IR spectra)
characteristics of humic substances isolated from soils of different origin and peat in Latvia are
described and compared with values common for humic substances of different origin, to evaluate
the character of processes during humification. Substantial dependence of properties of humic
substances on the humification conditions are found
A comparative study of the properties of industrially produced humic substances
Humic substances (HSs) are produced industrially in large quantities from low rank
coal, weathered coal, peat, also from soils, composts and other sources. Considering that the
applications of industrially produced HSs also include food, pharmaceutical applications and
environmental technologies, it is important to evaluate their composition and quality and to
identify their sources. The aim of the present study is to compare the properties of industrially
produced HS samples. HSs were characterised using spectroscopic and other methods. For the
identification of origin of HSs, different methods can be used, such as elemental analysis and
ratios of light stable isotopes. The results of the study indicate that many industrially produced
HSs are of poor quality (low concentration of basic substance, admixture of undesirable
substances, pollutants, no quality indications). In this situation, rigorous quality control should
be implemented, providing detailed characteristics of the product. The composition of materials
suggested for agricultural applications has not been analysed much. Most of the studied materials
were designated as HAs, followed by fulvic acids (FAs) and HSs. However, an analysis of the
humic matter types indicates that the majority of substances offered on the market are in fact
mixtures of HAs and FAs; so, it would be more appropriate to designate them as HSs or their
salts. This study identifies the main quality problems of industrially produced humic substances:
1) lack of strict quality indicators, 2) absence of indication of source materials/origins of HSs
Noteworthy records and natural history comments on rare and threatened bird species from Santa Cruz province, Patagonia, Argentina
Santa Cruz province is the second largest province in Argentina, and also the least populated. !is province makes up the southern tip of continental Argentina. Althought it has low population density and is remote from big cities, in the past it received well-deserved attention from researchers. !is was probably due to the presence of many interesting species, among them some threatened, with taxonomic singularities, and/or endemism. !e goal of this work is to update knowledge of the distribution and natural history of 21 species from Santa Cruz, including five new to the province.Fil: Roesler, Carlos Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Imberti, Santiago. Asociación Ambiente Sur; ArgentinaFil: Casañas, Hernán E.. Asociación Ornitológica del Plata; ArgentinaFil: Hernandez, Pablo M.. Fundación Flora y Fauna Argentina; ArgentinaFil: Klavins, Juan M..Fil: Pagano, Luis G.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados; Argentin
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