14 research outputs found

    Simbiotske zvijezde

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    Soil reaction_ a crucial preconditions for choosing horticultural plants

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    Da bismo vanjski prostor što ljepše i ekonomičnije uredili, potrebno je dobro poznavati tlo i biljku, ali i sve one čimbenike koji na njih utječu. Oblikovanje prostora, bilo da se radi o okućnici ili bilo kojem drugom segmentu krajolika: voćnjaku, vinogradu, povrtnjaku, cvjetnjaku ili travnjaku, a to znači hortikulturi u njezinom punom značenju, zahtijeva pomno planiranje i pripremu. Jedan od vrlo važnih čimbenika u pripremi tla je dobro poznavanje reakcije tla (pH). Reakcija tla značajno utječe na primanje svih hraniva, a varira ovisno o potrebama kultura od kiselog do alkalnog. Cilj ovog rada je detaljno obraditi potrebe pojedinih ukrasnih vrsta za reakcijom tla, koristeći rezultate terenskih istraživanja i uspoređujući ih s navodima u literaturi. U tu svrhu korištene su kemijske analize (reakcija tla u 1M KCl) koje je proveo Zavod za ishranu bilja, Agronomskog fakulteta Sveučilišta u Zagrebu, uz vizualno praćenje u okolišu. Prema dobivenim rezultatima istraživanja 47% od ukupno 131 očitanog uzorka spada u neutralna tla (D). U alkalna tla (E) spada 37%, u slabo kisela (C) spada 11%, u kisela tla (B) 5 %, a u kategoriju jako kiselih tala (A) ušao je samo jedan uzorak. Stoga rezultati naših istraživanja ukazuju da često puta navodi u literaturi za pojedine ukrasne vrste nisu apsolutno primjenjivi u datim okolnostima, odnosno da su primjenjivi uz manje ili veće korekcije. Općenito se za krajobrazno uređenje individualnih i javnih površina preporuča slabo kisela do neutralna reakcija tla (5,5,-7,2 – CD), jer većina ukrasnog bilja uspješno raste u tom rasponu. Za vrste koje više vole ekstremnu pH reakciju tla, potrebno je provesti korekciju primjenom adekvatnih gnojiva ili supstrata. Tako se Erica sp. i Rhododendron sp. preporučuju za jako kisela i kisela tla (pH 4,0-5,5 – AB) dok za slabo kisela tla (5,5-6,5 – C) predlažemo Abies sp., Cupressus sp., Juniperus sp., Pinus sp., te trave. Za kiselo tlo (4,5-5,5 – B) predlažemo Hydrangeu (plavu), Ilex sp., te Picea sp. Za slabo kiselo i neutralno tlo (5,5-7,2 – CD) Chrysanthemum sp., Magnolia sp., Quercus sp., Rosa sp. i Hedera sp. Neutralna reakcija (6,5-7,2 – D) optimalna je za rodove Chamaecyparis i Prunus. Za tla neutralne i alkalne reakcije (6,5-7,2 – DE) predlažemo nešto veći broj vrsta iz rodova Acer, Araucaria, Buxus, Crataegus, Forsythia, Hydrangea (roza i bijela), Lavandula, Thuja, te Vinca. Širok raspon reakcije tla (5,5-7,5 – CDE) podnose vrste iz roda Carpinus, Cedrus, Corylus, Cotinus, Cotoneaster i Taxus.Economy and aesthetic quality of landscaping require a good knowledge of soil and plant, but also of all the factors that affect them. Landscaping, wether a private holding or any other segment of the landscape: orchard, vineyard, vegetable garden, flower garden or lawn, which means horticulture in the full sense of the word, requires careful planning and preparation. One of the very important factors in soil preparation is a good understanding of soil reaction (pH). Soil reaction has a strong influence on all nutrients uptake and varies, dependending on crop requirements, from acid to alkaline. The aim of this paper is to deal in detail with the soil reaction requirements of particular ornamental species, using the results of field research and comparing them with the literature reports. For this purpose, use was made of the chemical analyses (soil reaction in 1M KCl) made in the Department of Plant Nutrition, Faculty of Agriculture, University of Zagreb, along with visual monitoring in the landscape. According to the research results, 47% of the 131 analyzed samples are neutral soils (D), 37% alkaline soils (E), 11% weakly acid soils (C), 5% acid soils (B), while only one sample belongs to the category of very acid soils (A). Hence our results show that literature reports for particular ornamental species are often not absolutely applicable in the given conditions, or that their application requires certain corrections. Weakly acid to neutral soil reaction (5,5-7,2 – CD) is generally recommended for landscape planning of individual and public areas, because most ornamental plants grow well within this range. For species that prefer extreme pH reaction of the soil, corrections should be made by applying adequate fertilizers or substrates. Thus, Erica sp. and Rhododendron sp. are recommended for very acid and acid soils (pH 4,0-5,5 – AB) while we suggest Abies sp., Cupressus sp., Juniperus sp., Pinus sp., and grasses for weakly acid soils (5,5-6,5 – C). Hydrangea (blue), Ilex sp., and Picea sp. are recommended for acid soils (4,5-5,5 – B). Chrysanthemum sp., Magnolia sp., Quercus sp., Rosa sp. and Hedera sp. are recommended for weakly acid and neutral soils (5,5-7,2 – CD). Neutral reaction (6,5-7,2 – D) is optimal for genera Chamaecyparis and Prunus. A larger number of species from the genera Acer, Araucaria, Buxus, Crataegus, Forsythia, Hydrangea (pink and white), Lavandula, Thuja, and Vinca are recommended for soils of neutral and alkaline reaction (6,5-7,2 – DE). Species of the genera Carpinus, Cedrus, Corylus, Cotinus, Cotoneaster and Taxus tolerate a wide range of soil reaction (5,5-7,5 – CDE)

    Role of supstrate preparation in nursery production

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    Svakodnevno smo svjedoci rasta zahtjeva tržišta za kvalitetnim i novim vrstama ukrasnog bilja. Međutim, u dosadašnjoj praksi nedovoljno se vodilo računa o stvaranju povoljnih uzgojnih uvjeta, uzgojnoj tehnologiji, te o zahtjevima tržišta. Naročito se to odnosi na pripremu kvalitetnog uzgojnog supstrata, koji se razlikuju za različite biljne vrste i različite faze rasta i razvoja biljaka. Uglavnom je prevladavalo mišljenje da se problem uzgojnog supstrata može riješiti u tijeku proizvodnje, gnojidbom organskim i mineralnim gnojivima. Rezultat toga su nepovoljna fizikalna svojstva (zbijenost, slaba vodopropusnost i mali kapacitet tla za zrak) i/ili loša kemijska svojstava tla (nepovoljna pH reakcija, neadekvatna opskrbljenost hranivima, visoka razina soli i visoka količina fiziološki aktivnog vapna). U cilju utvrđivanja utjecaja pripreme tla na rast i razvoj biljaka provedena su brojna istraživanja u rasadnicima i na većem broju lokaliteta gdje su se pojavili problemi u uzgoju ukrasnog bilja. U tu svrhu, prosječni uzorci tla uzeti su u rasadnicima Markuševac i Jankomir - Zrinjevac d.o.o., rasadniku Krnjić d.d. u Popovači, u više parkova u gradu Zadru, Zagrebu i Koprivnici, te s više okućnica. Zajednička karakteristika svih analiziranih tala su nepovoljna fizikalna i kemijska svojstva koja su rezultirala slabijim rastom i razvojem biljaka, a u ekstremnijim slučajevima i sušenjem biljaka. Da se ovakvi neželjeni efekti ne bi pojavljivali u budućnosti predlažemo analizu fizikalno-kemijskih svojstava tla kao prvi korak kod podizanja rasadnika ili sadnje biljaka na trajno mjesto uzgoja.There is an increasing demand for new and good-quality species of ornamental plants. In practice so far, however, insufficient attention has been paid to provision of favourable growing conditions, production technology, and market demands. This especially applies to the preparation of good growing substrates, which differs for different plant species and different stages of plant growth and development. It was generally thought that the substrate problem could be solved in the course of production by the application of organic and mineral fertilizers. Such practice resulted in unfavourable physical properties (compactness, poor water permeability and low air capacity) and/or poor chemical properties of soil (unfavourable pH reaction, inadequate nutrient availability, high salt levels and a high amount of physiologically active lime). To determine the influence of soil preparation on plant growth and development, numerous investigations were conducted in nurseries and at a number of localities where problems were encountered in the production of ornamental plants. For this purpose, average samples of soil and plant material (Chamaecyparis sp. and Thuja sp.) were taken from the nurseries Markuševac and Jankomir, owned by the company Zrinjevac d.o.o., the nursery Krnjić d.d. at Popovača, and from the main square and the park in Koprivnica, the islands of Pag, Vir, Prvić, as well as from Trsat and several locations in the cities of Zadar and Zagreb. The common characteristic of all the analyzed soils are their unfavourable physical and/or chemical properties, resulting in poorer growth and development of plants, and in extreme cases in plant drying. To prevent such undesirable effects in the future, the authors propose analysis of soil physical and chemical properties as the first step in setting up nurseries or plant production at a permanent location

    PLANT NUTRIENT CAPACITY OF SOILS AT VRANA VALLEY

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    Kontrola plodnosti tla kao prvi korak u ostvarenju cilja optimalne i harmonične ishranjenosti povrćarskih kultura provedena je na 730 ha otvorenih površina \u27\u27Vrana d.o.o.\u27\u27 tijekom 2004. godine, na četiri lokaliteta: Jankolovica, Jasen, Sokoluša i Tinj (550, 106, 30 i 44 ha), te na 6 ha stakleničke proizvodnje. Cilj provedenih istraživanja je bio utvrditi kemijska svojstva i biljno hranidbeni kapacitet tala te na temelju istih i potreba pojednih povrćarskih kultura dati preporuku za gnojidbu tla organskim i mineralnim gnojivima. Utvrđeno je da se radi o tlima neutralne do alkalne reakcije (pHKCl 7,1 – 7,8), bogato do vrlo bogato opskrbljenim humusom (4,2 – 16,0 %) i ukupnim dušikom (0,22 – 0,65 %). Vrlo slaba do slaba opskrbljenost tla fosforom (<10 mg/100 g) utvrđena je AL-metodom u 90 % uzoraka na lokalitetu Jankolovica, u svim uzorcima tla na lokalitetu Jasen i u 40 % uzoraka na lokalitertu Tinj. Opskrbljenost tla kalijem je umjerena do vrlo bogata u 92 % uzoraka na lokalitetu Jankolovica i u 68 % uzoraka na lokalitetu Jasen te vrlo bogata u 80 % uzoraka na lokalitetu Tinj. Količina fiziološki aktivnog vapna je umjerena do vrlo visoka (14 – 49 % CaO), što može predstavljati probleme u primanju magnezija, fosfora te mikroelemenata. Kako se radi o tlima bogato opskrbljenim kalijem i vapnom, a slabo opskrbljenim fosform, postoji potreba za napuštanjem ustaljene gnojidbe tla NPK gnojivima. Na većini lokacija gnojidba bi se trebala provoditi pojedinačnim fosfornim gnojivima.Soil fertility control, as the first step towards achieving the goal of optimal and harmonious nutrition of vegetable crops, was applied on 730 ha open areas of «Vrana» d.o.o. in 2004, on four localities: Jankolovica, Jasen, Sokoluša i Tinj (550, 106, 30 i 44 ha) and 6 ha greenhouses. with the aim to determine the chemical properties and plant nutrient capacity of the soils, which would be used to recommend soil fertilization with organic and mineral fertilizers. Results of chemical analyses showed that the soils are of neutral to alkaline reaction (pHKCl 7.1 – 7.8), richly to very richly supplied with humus (4.2 – 16.0 %) and total nitrogen (0.22-0.65 %). Very poor to poor soil phosphorus supply (<10 mg/100 g) was determined by the AL-method in 90 % soil samples from Jankolovica locality, in all samples from Jasen locality and in 40 % samples from Tinj locality. Soil supply of potassium was moderate to very rich in 92 % samples from Jankolovica and in 68 % samples from Jasen, and very rich in 80 % samples from Tinj. Available lime levels are very high (14–49 % CaO), which may cause problems in the uptake of magnesium, phosphorus, and microelements. Since the studied soils are rich in potassium and lime, and poorly supplied with phosphorus, it is recommendable to abandon the established fertilization with NPK fertilizers. The majority of production areas should be fertilized with particular phosphorus fertilizers

    Relation between the luminosity of young stellar objects and their circumstellar environment

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    We present a new model-independent method of comparison of NIR visibility data of YSOs. The method is based on scaling the measured baseline with the YSO's distance and luminosity, which removes the dependence of visibility on these two variables. We use this method to compare all available NIR visibility data and demonstrate that it distinguishes YSOs of luminosity >1000L_sun (low-L) from YSOs of <1000L_sun (high-L). This confirms earlier suggestions, based on fits of image models to the visibility data, for the difference between the NIR sizes of these two luminosity groups. When plotted against the ``scaled'' baseline, the visibility creates the following data clusters: low-L Herbig Ae/Be stars, T Tauri stars, and high-L Herbig Be stars. The T Tau cluster is similar to the low-L Herbig Ae/Be cluster, which has ~7 times smaller ``scaled'' baselines than the high-L Herbig Be cluster. We model the shape and size of clusters with different image models and find that low-L Herbig stars are the best explained by the uniform brightness ring and the halo model, T Tauri stars with the halo model, and high-L Herbig stars with the accretion disk model. However, the plausibility of each model is not well established. Therefore, we try to build a descriptive model of the circumstellar environment consistent with various observed properties of YSOs. We argue that low-L YSOs have optically thick disks with the optically thin inner dust sublimation cavity and an optically thin dusty outflow above the inner disk regions. High-L YSOs have optically thick accretion disks with high accretion rates enabling gas to dominate the NIR emission over dust. Although observations would favor such a description of YSOs, the required dust distribution is not supported by our current understanding of dust dynamics.Comment: 20 pages, 12 figures, Accepted for publication in the Astrophysical Journa

    Near infrared and the inner regions of protoplanetary disks

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    We examine the ``puffed-up inner disk'' model (Dullemond, Dominik & Natta 2001), proposed for explaining the near-IR excess radiation from Herbig Ae/Be stars. Detailed model computations show that the observed near-IR excess requires more hot dust than is contained in the puffed-up disk rim. The rim can produce the observed near-IR excess only if its dust has perfectly gray opacity, but such dust is in conflict with the observed 10μ\mum spectral feature. We find that a compact (\sim 10 AU) tenuous (\tau_V \la 0.4) dusty halo around the disk inner regions contains enough dust to readily explain the observations. Furthermore, this model also resolves the puzzling relationship noted by Monnier and Millan-Gabet (2002) between luminosity and the interferometric inner radii of disks.Comment: 14 pages, 10 figures, accepted in Ap

    From Data to Software to Science with the Rubin Observatory LSST

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    The Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) dataset will dramatically alter our understanding of the Universe, from the origins of the Solar System to the nature of dark matter and dark energy. Much of this research will depend on the existence of robust, tested, and scalable algorithms, software, and services. Identifying and developing such tools ahead of time has the potential to significantly accelerate the delivery of early science from LSST. Developing these collaboratively, and making them broadly available, can enable more inclusive and equitable collaboration on LSST science. To facilitate such opportunities, a community workshop entitled "From Data to Software to Science with the Rubin Observatory LSST" was organized by the LSST Interdisciplinary Network for Collaboration and Computing (LINCC) and partners, and held at the Flatiron Institute in New York, March 28-30th 2022. The workshop included over 50 in-person attendees invited from over 300 applications. It identified seven key software areas of need: (i) scalable cross-matching and distributed joining of catalogs, (ii) robust photometric redshift determination, (iii) software for determination of selection functions, (iv) frameworks for scalable time-series analyses, (v) services for image access and reprocessing at scale, (vi) object image access (cutouts) and analysis at scale, and (vii) scalable job execution systems. This white paper summarizes the discussions of this workshop. It considers the motivating science use cases, identified cross-cutting algorithms, software, and services, their high-level technical specifications, and the principles of inclusive collaborations needed to develop them. We provide it as a useful roadmap of needs, as well as to spur action and collaboration between groups and individuals looking to develop reusable software for early LSST science.Comment: White paper from "From Data to Software to Science with the Rubin Observatory LSST" worksho

    From Data to Software to Science with the Rubin Observatory LSST

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    editorial reviewedThe Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) dataset will dramatically alter our understanding of the Universe, from the origins of the Solar System to the nature of dark matter and dark energy. Much of this research will depend on the existence of robust, tested, and scalable algorithms, software, and services. Identifying and developing such tools ahead of time has the potential to significantly accelerate the delivery of early science from LSST. Developing these collaboratively, and making them broadly available, can enable more inclusive and equitable collaboration on LSST science. To facilitate such opportunities, a community workshop entitled "From Data to Software to Science with the Rubin Observatory LSST" was organized by the LSST Interdisciplinary Network for Collaboration and Computing (LINCC) and partners, and held at the Flatiron Institute in New York, March 28-30th 2022. The workshop included over 50 in-person attendees invited from over 300 applications. It identified seven key software areas of need: (i) scalable cross-matching and distributed joining of catalogs, (ii) robust photometric redshift determination, (iii) software for determination of selection functions, (iv) frameworks for scalable time-series analyses, (v) services for image access and reprocessing at scale, (vi) object image access (cutouts) and analysis at scale, and (vii) scalable job execution systems. This white paper summarizes the discussions of this workshop. It considers the motivating science use cases, identified cross-cutting algorithms, software, and services, their high-level technical specifications, and the principles of inclusive collaborations needed to develop them. We provide it as a useful roadmap of needs, as well as to spur action and collaboration between groups and individuals looking to develop reusable software for early LSST science

    Cargo operations systems on Oak Spirit

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    Važnost ovog rada temelji se na osvrtu drugog broda za prijevoz ukapljenog prirodnog plina koji je ikada sagrađen s ugrađenim ME-GI (Main Engine Gas Injection) pogonom, a to je Oak Spirit kompanije Teekay. U radu će se govoriti o sustavima za upravljanje teretom koji su u tadašnje vrijeme bili potpuno novi i inovativni, kao što su sustav za djelomično reukapljivanje, spojeni sustav inertnog plina i sustav za spaljivanje viška isparenog tereta, HiVAR (high pressure vaporizer) sustav i HiCOM (high pressure compressor) sustav. Posebna pažnja će se obratiti i na pumpe tereta i cjevovode te na način njihove izrade i rada koji je krucijalan za sigurno i djelotvorno rukovanje teretom pogotovo u izvanrednim situacijama.The importance of this work is based on a review of the second ever liquefied natural gas vessel with a built-in ME-GI (Main Engine Gas Injection) propulsion and that is the Oak Spirit from Teekay company. The work will discuss about cargo management systems that were completely new and innovative at the time, such as the partial reliquefaction system, the combined inert gas system and gas combustion unit, the HiVAR (high pressure vaporizer) system and HiCOM. (high pressure compressor) system. Special attention will be paid to cargo pumps and pipelines and to the way they are manufactured and operated, which is crucial for safe and efficient cargo handling, especially in emergency situations

    Cargo operations systems on Oak Spirit

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    Važnost ovog rada temelji se na osvrtu drugog broda za prijevoz ukapljenog prirodnog plina koji je ikada sagrađen s ugrađenim ME-GI (Main Engine Gas Injection) pogonom, a to je Oak Spirit kompanije Teekay. U radu će se govoriti o sustavima za upravljanje teretom koji su u tadašnje vrijeme bili potpuno novi i inovativni, kao što su sustav za djelomično reukapljivanje, spojeni sustav inertnog plina i sustav za spaljivanje viška isparenog tereta, HiVAR (high pressure vaporizer) sustav i HiCOM (high pressure compressor) sustav. Posebna pažnja će se obratiti i na pumpe tereta i cjevovode te na način njihove izrade i rada koji je krucijalan za sigurno i djelotvorno rukovanje teretom pogotovo u izvanrednim situacijama.The importance of this work is based on a review of the second ever liquefied natural gas vessel with a built-in ME-GI (Main Engine Gas Injection) propulsion and that is the Oak Spirit from Teekay company. The work will discuss about cargo management systems that were completely new and innovative at the time, such as the partial reliquefaction system, the combined inert gas system and gas combustion unit, the HiVAR (high pressure vaporizer) system and HiCOM. (high pressure compressor) system. Special attention will be paid to cargo pumps and pipelines and to the way they are manufactured and operated, which is crucial for safe and efficient cargo handling, especially in emergency situations
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