1,060 research outputs found
Role of stocking density of tilapia (Oreochromis aureus) on fish growth, water quality and tomato (Solanum lycopersicum) plant biomass in the aquaponic system
The present study reports the results of the production of Nile tilapia (Oreochromis aureus) and tomato (Solanum lycopersicum) in the classical aquaponic system (one-loop) with different fish density. The experiment as the first scientific aquaponics study in Turkey was conducted at the Ankara University, Faculty of Agriculture, using in-door, small-scale classical aquaponic systems. Ninety six tilapia juveniles (O. aureus) were stocked at different ratio; 25 kg/m3 (Group I), 35 kg/m3 (Group II) and 50 kg/m3 (Group III) and fed with 45% raw protein feed at the level of 2% body weight for 126 days. Fish density affected the fish growth parameters and the most densiest group showed the best results in terms of fish growth and feed efficiency. Water quality parameters measured fluctated during the experiment even the exceed of the optimal ranges for the fish. However, tilapia tolerated the changes of water quality. Total plant biomass was low with the various limiting factors including insufficient lighting of in-door aquaponics system and low level of water potassium. The results of this study clearly illustrate the fish stocking rate has an impact on total biomass in the aquaponics and in one-loop aquaponics the water quality fluctation is the main challenging factor
Performance of Some Forages Species (\u3cem\u3eFestuca arundinacea\u3c/em\u3e L., \u3cem\u3eChloris gayana\u3c/em\u3e var. Katambora, \u3cem\u3eLotus corniculatus\u3c/em\u3e L. and \u3cem\u3eMedicago sativa\u3c/em\u3e L.) in Saline Soil
Salinity is a soil degradation process which reduces plant diversity and agricultural productivity, decreases fertility and devalues the land in regions with arid and semi-arid climate. This process inhibits water and nutrient intake of plants from soil due to changeable nitrogen percentage and/or the intensity of soluble salt concentration. When the fact that agricultural lands are limited around the world and that the need for nutrition increases incrementally is taken into consideration, it is obvious that available lands should be used more effectively. Hence, it is quite crucial to reclaim saline soil and utilize it more economically (Woods 1996)
Studıes on determınatıon the effects of some practıcable classıfıcatıon methods on seed germınatıon of crımean junıper (juniperus excelsa bieb.) before sowıng process
Bu çalışmada, renklerine, büyüklüklerine, sakaroz çözeltisinde ve suda yüzme özelliklerine göre 8 sınıfa (IA: Açık renkli, IB: Koyu renkli, IIA: Büyük, IIB: Küçük, IIIA: Sakaroz çözeltisinde dibe çöken, IIIB: Sakaroz çözeltisinde yüzen, IVA: Suda dibe çöken, IVB: Suda yüzen tohumlar) ayrılan Boylu Ardıç (Juniperus excelsa Bieb.) tohumlarının fidanlık koşullarında çimlenme yetenekleri karşılaştırılmıştır. Açık hava koşullarında 45 cm x 35 cm boyutlarındaki ENSO tipi kaplarda gerçekleştirilen ekimler, “Tesadüf Parselleri Deneme Deseni”ne uygun ve 3 yinelemeli olarak yapılmıştır. Tohum sınıflarına ait çimlenme yüzdeleri ve fidecik sayılarına ait veriler “SPSS İstatistik Paket Programı”nda değerlendirilmiştir. Buna göre; en yüksek çimlenme yüzdesi (%51.3), koyu renkli tohum sınıfında (IB) elde edilmiştir. Ekonomik ve aynı zamanda uygulamaya dönük olması açısından Boylu Ardıç fidanı üretiminde, tohumların suda yüzdürülerek sınıflandırılabileceği ve buna bağlı olarak da yüzen tohumların dibe çökenlere kıyasla daha fazla çimlenme kabiliyetinde oldukları ortaya çıkmıştır.In this study, the germination and seedling percent of Crimean Juniper (Juniperus excelsa Bieb.) seeds which were classified into eight classes according to their colours (IA: light-coloured and IB: darkcoloured seeds), morphological appearance (IIA: large-sized and IIB: small-sized seeds), floating ability in saccharine solution (IIIA: floated and IIIB: sunken seeds) and water (IVA: floated and IVB: sunken seeds) were investigated. The seeds were sown to germinate in open-field conditions with sowing Enso-potray of 45x35 cm in size, and the experimental design was “Completely Randomised Design” with three replications. Germination data on seed classes were analyzed using SSPS statistical software. Analysis of variance and Duncan test showed that the highest germination percent (51.3%) was provided by dark-coloured (IB) seeds. In conclusion, as it is easy to practice and economical method for production of Crimean Juniper Seedlings in forest nurseries, the seeds could be classified by floating process in water. It could be said that the germination ability of the floated seeds in water are much better than those of the sunken seeds
Simulation of annual plankton productivity cycle in the Black Sea by a one-dimensional physical-biological model
The annual cycle of the plankton dynamics in the central Black Sea is studied by a one-dimensional vertically resolved physical-biological upper ocean model, coupled with the Mellor-Yamada level 2.5 turbulence closure scheme. The biological model involves interactions between the inorganic nitrogen (nitrate, ammonium), phytoplankton and herbivorous zooplankton biomasses, and detritus. Given a knowledge of physical forcing, the model simulates main observed seasonal and vertical characteristic features, in particular, formation of the cold intermediate water mass and yearly evolution of the upper layer stratification, the annual cycle of production with the fall and the spring blooms, and the subsurface phytoplankton maximum layer in summer, as well as realistic patterns of particulate organic carbon and nitrogen. The computed seasonal cycles of the chlorophyll and primary production distributions over the euphotic layer compare reasonably well with the data. Initiation of the spring bloom is shown to be critically dependent on the water column stability. It commences as soon as the convective mixing process weakens and before the seasonal stratification of surface waters begins to develop. It is followed by a weaker phytoplankton production at the time of establishment of the seasonal thermocline in April. While summer nutrient concentrations in the mixed layer are low enough to limit production, the layer between the thermocline and the base of the euphotic zone provides sufficient light and nutrient to support subsurface phytoplankton development. The autumn bloom takes place some time between October and December depending on environmental conditions. In the case of weaker grazing pressure to control the growth rate, the autumn bloom shifts to December-January and emerges as the winter bloom or, in some cases, is connected with the spring bloom to form one unified continuous bloom structure during the January-March period. These bloom structures are similar to the year-to-year variabilities present in the data
Simulation of annual plankton productivity cycle in the Black Sea by a one-dimensional physical-biological model
The annual cycle of the plankton dynamics in the central Black Sea is studied by a one-dimensional vertically resolved physical-biological upper ocean model, coupled with the Mellor-Yamada level 2.5 turbulence closure scheme. The biological model involves interactions between the inorganic nitrogen (nitrate, ammonium), phytoplankton and herbivorous zooplankton biomasses, and detritus. Given a knowledge of physical forcing, the model simulates main observed seasonal and vertical characteristic features, in particular, formation of the cold intermediate water mass and yearly evolution of the upper layer stratification, the annual cycle of production with the fall and the spring blooms, and the subsurface phytoplankton maximum layer in summer, as well as realistic patterns of particulate organic carbon and nitrogen. The computed seasonal cycles of the chlorophyll and primary production distributions over the euphotic layer compare reasonably well with the data. Initiation of the spring bloom is shown to be critically dependent on the water column stability. It commences as soon as the convective mixing process weakens and before the seasonal stratification of surface waters begins to develop. It is followed by a weaker phytoplankton production at the time of establishment of the seasonal thermocline in April. While summer nutrient concentrations in the mixed layer are low enough to limit production, the layer between the thermocline and the base of the euphotic zone provides sufficient light and nutrient to support subsurface phytoplankton development. The autumn bloom takes place some time between October and December depending on environmental conditions. In the case of weaker grazing pressure to control the growth rate, the autumn bloom shifts to December-January and emerges as the winter bloom or, in some cases, is connected with the spring bloom to form one unified continuous bloom structure during the January-March period. These bloom structures are similar to the year-to-year variabilities present in the data
Comparıson of seed sources of crımean junıper (juniperus excelsa bieb.) ın the lakes dıstrıct ın terms of morphologıcal seedlıng qualıty crıterıa
Bu çalışmada, Göller Yöresi’nden örneklenen beş Boylu Ardıç (Juniperus excelsa Bieb.) orijini, bazı morfolojik fidan kalite kriterleri bakımından karşılaştırılmıştır. Bu amaçla, Barla, Sultandağı, Tota, Burdur, Söğüt orijinlerinden tohum toplanmıştır. Her orijine ait tohumlar, Eğirdir Orman Fidanlığı’nda açık hava koşulları altında özel olarak hazırlanan ekim yastıklarına ekilmiştir. Denemede, üç yinelemeli Tesadüf Parseller Deneme Deseni Kullanılmıştır. Her orijine ait bir yaşlı fidanlarda fidan boyu, kök boğazı çapı, gövde ve kök kuru ağırlıkları ile gövde/kök kuru ağırlık oranı belirlenmiştir. Bu amaçla her orijinden her bir yinelemede on fidan ölçülmüştür. Elde edilen veriler, SPSS paket programında değerlendirilmiştir. Yapılan varyans analizi ve Duncan testi, orijinlerin, ölçülen fidan karakterleri bakımından birbirinden farklı olduklarını göstermiştir. Buna göre, yeni ve daha kapsamlı çalışmalar sonuçlanana kadar, Eğirdir Orman Fidanlığı’nda yapılan Boylu Ardıç fidanı yetiştirme çalışmalarında kullanılacak tohumların öncelikle Tota ve Barla orijinlerinden toplanması durumunda kalite kriterleri bakımından daha üstün özelliklere sahip fidanların yetiştirilebileceği ortaya çıkmıştır.Bu sonuç, çalışmanın gerçekleştirildiği Eğirdir Orman Fidanlığı için geçerlidir.In this study, five seed provenances of Crimean Juniper sampled from Lakes District were compared in terms of some seed quality criterions. For this purpose, seeds were collected from Barla, Sultandağı, Tota, Burdur and Söğüt. The seeds from each provenance were sown in Eğirdir Forest Nursery under the open-air environment and the sowing bed was prepared specially. The experiments were carried out according to “Completely Randomized Design” with three replications. Seedling height, root collar diameter and oven-dry stem/root ratios of ten seedlings were measured from each replication after the seedlings were one-year old. Data were analyzed by using SPSS statistical software program. Analysis of variance (ANOVA) and Duncan test results showed that the seed provenances were different from each other in terms of measured characteristics. Until the new and extensive study results are obtained, the seeds should be collected from the provenances of Tota and Barla because those seedlings are better than the others. However, these results are valid only Eğirdir Forest Nursery and its environment should not be generalized for the other nurseries
CAST: Recent results & future outlook
Çetin, Serkant Ali (Dogus Author) -- Ezer, Cemile (Dogus Author) -- Yıldız, Süleyman Cenk (Dogus Author) -- Conference full title: 6th Patras Workshop on Axions, WIMPs and WISPs, PATRAS 2010; Zurich; Switzerland; 5 July 2010 through 9 July 2010.The CAST (CERN Axion Solar Telescope) experiment is searching for solar axions by their conversion into photons inside the magnet pipes of an LHC dipole. The analysis of data taken so far has shown no signal above the background, thus implying an upper limit to the axion-photon coupling of ga < 0.85 × 10-10GeV -1 at 95% CL for ma < 0.02 eV/c2. Ongoing measurements, with the magnet bores filled with a buffer gas (3He), are improving the sensitivity of the experiment for higher axion masses towards 1 eV/c2. Recent results, new ideas for Axion-Like Particle (WISPs) searches with CAST in the near future and the prospects of a new generation Helioscope are presented here
First principles modelling of magnesium titanium hydrides
Mixing Mg with Ti leads to a hydride Mg(x)Ti(1-x)H2 with markedly improved
(de)hydrogenation properties for x < 0.8, as compared to MgH2. Optically, thin
films of Mg(x)Ti(1-x)H2 have a black appearance, which is remarkable for a
hydride material. In this paper we study the structure and stability of
Mg(x)Ti(1-x)H2, x= 0-1 by first-principles calculations at the level of density
functional theory. We give evidence for a fluorite to rutile phase transition
at a critical composition x(c)= 0.8-0.9, which correlates with the
experimentally observed sharp decrease in (de)hydrogenation rates at this
composition. The densities of states of Mg(x)Ti(1-x)H2 have a peak at the Fermi
level, composed of Ti d states. Disorder in the positions of the Ti atoms
easily destroys the metallic plasma, however, which suppresses the optical
reflection. Interband transitions result in a featureless optical absorption
over a large energy range, causing the black appearance of Mg(x)Ti(1-x)H2.Comment: 22 pages, 9 figures, 4 table
Examining the roles of child temperament and teacher-child relationships as predictors of Turkish children’s social competence and antisocial behavior
The present study examined the concurrent contribution of Turkish children’s temperament and teacher-child relationship quality to their social competence and antisocial behavior, with a specific focus on the moderating role of teacher-child relationships (closeness and conflict) on children’s temperament (inhibitory control and shyness) when predicting social competence and antisocial behavior. Participants were 94 children (56 boys) with mean age of 7.05 years (SD = .88) enrolled in 24 classrooms from five elementary schools in a suburban school district in Turkey. Mothers reported on children’s temperament and teachers reported on their relationships with children as well as children’s social competence and antisocial behavior. SAS PROC MIXED was used to test hierarchical regression models of children nested within classrooms. Results showed that high conflict teacher-child relationships moderated the association between low shyness and antisocial behavior. Less shy children displayed more antisocial behavior at higher levels of teacher-child conflict. In addition, at high levels of child shyness, social competence ratings improved as teacher-child closeness increased. Inhibitory control was positively correlated with social competence and negatively correlated with antisocial behavior. The qualities of teacher-child relationships can effectively support children’s social competence and antisocial behavior depending upon their temperamental characteristics. Limitations and future directions of the current study are discussed
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Acetylsalicylic Acid Reduces the Severity of Dextran Sodium Sulfate-Induced Colitis and Increases the Formation of Anti-Inflammatory Lipid Mediators
The role of non-steroidal anti-inflammatory drugs in inflammatory bowel disease is controversial, as they have been implicated in disease aggravation. Different from other cyclooxygenase inhibitors, acetylsalicylic acid (ASA) enhances the formation of anti-inflammatory and proresolution lipoxins derived from arachidonic acid as well as resolvins from omega-3 polyunsaturated fatty acids such as docosahexaenoic acid (DHA). In this study, we examined the effect of ASA on murine dextran sodium sulfate colitis. A mouse magnetic resonance imaging (MRI) protocol and post mortem assessment were used to assess disease severity, and lipid metabolites were measured using liquid chromatography-coupled tandem mass spectrometry. Decreased colitis activity was demonstrated by phenotype and MRI assessment in mice treated with ASA, and confirmed in postmortem analysis. Analysis of lipid mediators showed sustained formation of lipoxin A4 and an increase of DHA-derived 17-hydroxydocosahexaenoic acid (17-HDHA) after treatment with ASA. Furthermore, in vitro experiments in RAW264.7 murine macrophages demonstrated significantly increased phagocytosis activity after incubation with 17-HDHA, supporting its proresolution effect. These results show a protective effect of ASA in a murine colitis model and could give a rationale for a careful reassessment of ASA therapy in patients with inflammatory bowel disease and particularly ulcerative colitis, possibly combined with DHA supplementation
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