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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Weed research 45 (2005), S. 0 
    ISSN: 1365-3180
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The critical period of weed interference in one variety of chickpea was determined in field experiments carried out at two sites, Tabriz 2002 and Kermanshah 2003, Iran. Chickpea culture was either kept free of weeds for 0, 12, 24, 36, 48 and 60 days after crop emergence (DAE) or weeds were allowed to grow for 0, 12, 24, 36, 48 and 60 DAE. In these experiments, chickpea yield increased with increasing duration of weed-free period and was reduced by increasing duration of weed-infested period. Unweeded conditions for the entire growing season caused 66.4% and 48.3% seed yield reduction when compared with the treatment that was weed-free throughout the growing season, at Tabriz 2002 and Kermanshah 2003, respectively. The results indicated that chickpea must be kept weed-free between the five-leaf and full flowering stages (24–48 DAE) and from the four-leaf to beginning of flowering stages (17–49 DAE) at the two sites, respectively, in order to prevent 〉10% seed yield loss. At both sites, reduction in seed yield, because of the increased weed interference period, was accompanied by simultaneous reduction in plant dry weight, number of branches, pods per plant and 100-seed weight. This was supported by significant and positive correlations between these traits and chickpea seed yield. There was no significant correlation between the number of seeds per pod and seed yield. A linear regression model was used to describe the relationship between weed dry weight and seed yield loss.
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2018-03-13
    Description: The impact of two principal parasitic digenetic trematodes, Meiogymnophallus minutus and Himasthla spp., on the growth (weight and length) of the cockle, Cerastoderma edule, in Arcachon Bay (France) was studied. The experiment was conducted in the land-based mesocosms. The velocity of infestation with both trematodes was far more rapid during summer in the cockles already parasitized with these trematodes (0.35 to 0.45 metacercariae day-1) than those of healthy ones (approximately 0.01 metacercariae day-1). The parasitism had also an effect on the growth rates of cockles. During 190 days of the experiment, the daily growth speed varied from 0.001mm.da/ to 0.021mm.day-1. On average, the growth was slightly more important in healthy cockles after the start of experiments (0.014mm.day-1) than those initially infested cockles (0.011 mm.day-1). The experiment also showed that infestation of hosts with trematodes could perhaps disturb their immunity system, as the intensification with trematode parasites had been favored by already infested cockles.
    Keywords: Biology ; Fisheries
    Repository Name: Aquatic Commons
    Type: Article , PeerReviewed
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  • 3
    Publication Date: 2018-03-01
    Description: Short-term oxygen consumption and filtration rate experiments were conducted to evaluate the response of edible cockle Cerastoderma edule when infested by the Digenean trematod Labratrema minimus. In this experiment the metabolic activities of bivalves were measured to detennine this particular aspect of the host-parasite interaction. We have used the Bucephalidae digenea Labratrema minimus infestation as a factor which can alter the metabolic rates of its host: the edible cockle Cerastoderma edule from Arcachon bay (France). The results show that specific oxygen consumption of infested cockles decreases in comparison with that of healthy ones. This decrease in specific pumping rate is partly due to increase in the total cockle biomass measured, which is due to the presence of the parasite and can represent 20% of a healthy cockle's O2 consumption (it can constitute up to 92% of live mass in high infestation ii1tensities(personal observations; 1996) but consume little oxygen. In addition, the disease provoked by infestation can reduce the true metabolic activities. The results show that pumping rate is related to the intensity of the infestation with greater infestation associated with lower oxygen consumption. We also demonstrate that L. minimus is capable of oxygen consumption regulation. The consumption rate is maintained below 0.3 mmol O2 min-1 g-1 FDW (Fresh Dry Weight) in all external oxygen concentrations experimented.
    Keywords: Biology ; Fisheries
    Repository Name: Aquatic Commons
    Type: Article , PeerReviewed
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  • 4
    Publication Date: 2018-03-06
    Description: In order to demonstrate filtration rate of edible cockle Cerastoderma edule under different salinity and temperature conditions, two groups namely healthy and infested with the parasite Labratrema minimus (Bucephallidae; Digenea) were compared. Results showed that the parasite-infested ones had difficulties in adaptation to the extreme conditions of salinity and temperature. Our results also showed that a healthy cockle could filter 78 ml min-1g-1 Flesh Dry Weight (FDW) seawater at 200e temperature and 34% salinity while an infested one processed 15.4 ml min-1g-1 FDW under the same conditions. In low salinity, which could happen during a rainy day and low tide, the healthy cockles processed 14.5 ml min-1g-1 FDW while infested cockles filtered 18.9 ml min-1g-1 FDW. Differences were not significant, however. Filtration rate of healthy cockles at a constant salinity but high temperature was 101.9 ml min-1g-1 FDW while the infested ones rated 27.2 ml min-1g-1 FDW. There was not a significant difference between their filtration rates at 20oC and 30oC. Our results showed that the parasite-infested cockles were unable to adapt to extreme conditions when an increase in temperature or a decrease in salinity occurred. If these results could be extrapolated to natural situations, the ecological cause of mortality due to parasites could be proved and explained.
    Keywords: Biology ; Fisheries
    Repository Name: Aquatic Commons
    Type: Article , PeerReviewed
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  • 5
    Publication Date: 2018-09-03
    Description: The present project in related to survey of factors and hydrology and hydrochemical features (water temperature, dissolve oxygen saturation, pH, clearance, salinity, nitrogen, phosphorus and silicon) hydrobiology (zooplankton, phytoplankton, macrobenthos) and survey of bio environment pollution (oil, heavy metal, detergent) executed in lower 10m in different water larger in southern Caspian Sea in 2002-2003. For sampling 8 lines number were vertical on coast that selected from Astra in west to Gomishan in east in southern Caspian Sea basin. The result indicated the average physical factors such as pH were 8.11 and salinity12.12 ppt ,and disolve oxygen6.7 mg/l. Average chemical factors such as NO_2 , NO_3 and NH_4 were 1.2 µg/l, 25.7 µg/l, 13 µg/l respectively.Total nitogen and organic nitrogen and inorganic nitrogen were 690.2 µg/l , 667.6 µg/l , 41.6 µg/l. Average silicat were recrded 266.35 µg/l . Total Phosphorus was observed 37.35 µg/l and average of organic Phosphorus concentration was and 20.25 µg/l .Average of Total organic matter (T.O.M) was 4.98% maximum amount were observed in Lisar and minimum in Nooshahr . Concentration of heavy metal during sampling were respectively ,Fe〉Mn〉Zn〉Cr〉Ph〉Co〉Cd〉Cu. Maximum concentration of Fe were determined in winter in Nooshahr and Babolsar respectively 13/3 µg/l 17/1 µg/l. In many stations and different Season, the amount of heavy meta were lower standard of in marine water. The concentration of oil hydrocarborate (PAHs) in autumn was 0/13 ppb and in winter 0/12 ppb. The amount of (PAHs) in Southern Caspian Sea were Lower than other parts of Caspian Sea. The average of detergent concentration (LAS) was 0/036 µg/l that was two fold higher than determined in 2001. Total 107 species of phytoplankton belong to 5 phylum were identified. The numbers of species of phytoplankton groups were respectively, chrysophyta (42 species), cyanophyta (17 species), pyruphyta (17 species), chlorophyta (21 species) and euglenophyta (9 species). The maximum diversity of phytoplankton observed in summer and minimum in autumn. High diversity of chrysophta and cyanophyta observed in summer and phyrophyta and chrlophyta in spring. The composition of phytoplanhkton groups were respectively, chrysophyta (70%), phyrophyta (9%) and chlorophyta (7%) and euglonophyta (1%). Maximum density of phytoplankton was observed in autumn and minimum in winter. Total 19 species of Zooplankton were identified. Maximum diversity was observed in summer and minimum in winter. Zooplankton changes during sampling, showed amount of density of zooplankton in 5m were more than 10 m depths. Total (17 species macrobenthos were identified. The composition of macrobenthos groups were respectively , Annalida (92/7% ) , Bivalvia (2/7%) gumarida (108%) cumacea ( 1/5%) , Balanidae 103% . max . density were observed in Astara and min . in Sefied roud Average of density were 1218 0/851 ind /m^2 and biomass 14 15 g/m^2 High density were recorded in autumn and low density in winter . Correlation of phytoplankton and zooplankton with physicochemical parameter and also relation between total organic matter and sediment grain size were calculated.Ecological indicies (simpson diversity evenns diversity and shanoon-wiever diversity) were calculated for macrobenthos. Data were shown impact of cetenephora (Mnenemiopsis leidyi) on zooplankton and phytoplankton and macrobenthos density.
    Keywords: Ecology ; Pollution
    Repository Name: Aquatic Commons
    Type: Monograph or Serial Issue , NonPeerReviewed
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  • 6
    Publication Date: 2018-03-26
    Description: In the present study, changes in benthic communities due to seasonal changes in the water of the southern Caspian Basin were investigated. Sampling was conducted monthly, from March 2006 to March 2007, at six selected stations in Tajan River mouth located on south eastern Caspian Sea. Also secondary benthic production consumable for fish and other biota inhabiting the mouth and adjacent areas were estimated. Forcing and limiting factors were also discussed. Benthic communities comprised 9 taxa, of which Balanus sp., Chironomus plumosus and Cerastoderma lamarki were the main contributors to both overall biomass and secondary production. Annual secondary production varied from 3.8g AFDWm-2 y-1, in the upper part of the mouth, to 78.06g AFDWm-2 y-1 in the center of the estuary area. Multivariate correlations between environmental variables and the macro benthic biomass highlighted the role of the water level, temperature, organic carbon content and dissolved oxygen which resulted in separation of communities in the estuary. Composition, biomass and secondary annual production of macro benthic communities were dramatically affected by changes in water residence time and summer drought crises. The isolation of this habitat limits the recovery of other benthic fauna during drought periods. Only populations of two taxa, Balanus sp. (Cirripeda) and C. plumosus (Diptera) seemed to be able to recover quickly after the drought crises, which, in turn, could compromise the overall secondary production, which may have negative effects on fish and other superior organism’s survival. During summer water renewal, when agricultural activities are intense, nutrient inputs should be regulated in this estuary to reduce the risk of benthic mass mortality and to ensure a sustainable ecosystem.
    Keywords: Ecology ; Fisheries
    Repository Name: Aquatic Commons
    Type: Article , PeerReviewed
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  • 7
    Publication Date: 2018-08-23
    Description: In 1999 Mnemiopsis leidyi was introduced to the Caspian Sea from the Black Sea with ballast waters from the ships. The comprehensive study on probability of controlling Caspian Sea invasive Ctenophora planned after a remarkable of decreeing in Kilka fish catches stocks and fisheris community problems. This study focus on reproduction experiments of Beroe ovata as the best candidate for control of Mnemiopsis population size in the Caspian Sea that was performed in Turkey and Iran during 2002-2003. At 2002, 87 specimens of B. ovata, 10-50 mm transferred to Caspian sea ecology research center from Marmareh sea where acclimated with Caspian sea water gradually. At 2003, experiments were performed near to Black sea (at Sinop) with freshly collected Beroe ovata, 40-65 mm size in three salinity level treatment, the Black sea water 18 , Mixed water 15 and Caspian water 12 . 130 individuals of Beroe ovata were brought from Sinop (Turkey) to Iran during 2003. A number of Beroe specimens were sent to Guilan province for reproduction studies and another part were sent to Mazandaran province for both reproduction and mesocosem studies. For control we had 1 Beroe, length 30 mm in the Black Sea water that was alive during of study in Iran. The Jars were examined each day for ova and larvae and they were collected and put into glass container of Caspian water for hatching and developing survey, some of them were left without any handling for larvae developing. Also in another experiment the eggs collected from jars were placed in the same three treatments for studying of growth and survival. The results were unsuccessful on propagation experiments at 2002 since the spawning and hatching rates were very low (20 ova) and, none of the larvae developed into adults in Caspian Sea water. The spawning was more in Marmareh sea water with 138 ova where only 7 larvae was hatched. Results showed that Beroe specimens is able to survive and reproduce in Caspian water but was not as well as Black Sea also the Beroe larvae growth rate is low in the Caspian Sea water. Maximum fecundity of Beroe individual was 2212 and 235 ovae in Caspian Sea water in site Sinop and Iran respectively. Results showed 34-100% eggs in Caspian Sea water were destroyed and did not develop. In Iran we obtained only one larvae with 5 mm length, other larvae were at different stages of development but most of them were 1.2 2 mm. The results of mesocosm survey showed most of ova and larvae have been obtained from the tanks where individuals B. ovata were with Mnemiopsis. Fecundity of Beroe in the control with Black Sea water were between 17 to 1879 with average of 828 ± 112 ova. The poor results of B. ovata reproduction obtained in this survey in Caspian Sea may be due to transportation and acclimation stress and low salinity of Caspian Sea water.
    Keywords: Ecology ; Fisheries
    Repository Name: Aquatic Commons
    Type: Monograph or Serial Issue , NonPeerReviewed
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  • 8
    Publication Date: 2017-12-03
    Description: The objective of this study was to determine the effect of human chorionic gonadotropin (hCG) on sexual maturation, plasma sex steroids [17β-estradiol, (E2) and 17α-hydroxy progesterone (17α_OHP)] and thyroid hormones (triiodothyronine, T3 and thyroxin, T4) levels in upstream - migrating Caspian lamprey. During the experiment, 36 fish (24 females and 12 males) in spring 2013 and 36 fish (24 females and 12 males) in fall 2013 were collected from the Shirud River estuary in Mazandaran Province, the Southern Caspian Sea during their upstream migration to the freshwater. All fish were injected with hCG at the doses of 1000, 1500 and 2000 IU.kg BW-1. The injection was a two - step process (50% of hormone in each step) by 12 h interval. After the first injection, fish were retained in the cages in the river beds and 24 hours after the second injection, fish were checked for egg and sperm release after mild abdomen pressure. Blood samples were taken for determining sex steroid levels. Results showed that hCG hormone injections caused increase in migration of germinal vesicle in the oocyte of female and sperm release in males. Significant differences were found in the serum E2 and 17α-OHP levels in hCG - injected fish compared to the control. However, no significant differences were found in serum T3 and T4 levels in the hCG -injected fish. According to the results, the appropriate hCG dosage to induce the reproduction acceleration in Caspian lamprey is 1500-2000 IU.kg BW-1.
    Keywords: Biology ; Fisheries
    Repository Name: Aquatic Commons
    Type: Article , PeerReviewed
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  • 9
    Publication Date: 2014-05-06
    Description: The synthesis of polysubstituted quinolines was accomplished through Friedländer annulation between 2-aminoaryl ketones and different active methylene compounds at room temperature using ball-milling technique in the presence of p -toluenesulfonic acid. The mechanism of the reaction investigated by density functional theory-based modeling is also reported. This study aims at giving insight into the mechanism of the Friedländer reaction in the presence of acid catalysts. Copyright © 2014 John Wiley & Sons, Ltd. The synthesis of polysubstituted quinolines was accomplished through Friedländer annulation between 2-aminoaryl ketones and different active methylene compounds at room temperature using ball-milling technique in the presence of p -toluenesulfonic acid. The mechanism of the reaction investigated by density functional theory-based modeling is also reported. This study aims at giving insight into the mechanism of the Friedländer reaction in the presence of acid catalysts.
    Print ISSN: 0894-3230
    Electronic ISSN: 1099-1395
    Topics: Chemistry and Pharmacology , Physics
    Published by Wiley
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  • 10
    Publication Date: 2019
    Description: In this study, a cooling/power cogeneration cycle consisting of vapor-compression refrigeration and organic Rankine cycles is proposed and investigated. Utilizing geothermal water as a low-temperature heat source, various operating fluids, including R134a, R22, and R143a, are considered for the system to study their effects on cycle performance. The proposed cycle is modeled and evaluated from thermodynamic and thermoeconomic viewpoints by the Engineering Equation Solver (EES) software. Thermodynamic properties as well as exergy cost rates for each stream are found separately. Using R143a as the working fluid, thermal and exergy efficiencies of 27.2% and 57.9%, respectively, are obtained for the cycle. Additionally, the total product unit cost is found to be 60.7 $/GJ. A parametric study is carried out to determine the effects of several parameters, such as turbine inlet pressure, condenser temperature and pressure, boiler inlet air temperature, and pinch-point temperature difference, on the cycle performance. The latter is characterized by such parameters as thermal and exergy efficiencies, refrigeration capacity, produced net power rate, exergy destruction rate, and the production unit cost rates. The results indicate that the system using R134a exhibits the lowest thermal and exergy efficiencies among other working fluids, while the systems using R22 and R143a exhibit the highest energy and exergy efficiencies, respectively. The boiler and turbine contribute the most to the total exergy destruction rate.
    Electronic ISSN: 2071-1050
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by MDPI
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