310 research outputs found
More than one dynamic crossover in protein hydration water
Studies of liquid water in its supercooled region have led to many insights
into the structure and behavior of water. While bulk water freezes at its
homogeneous nucleation temperature of approximately 235 K, for protein
hydration water, the binding of water molecules to the protein avoids
crystallization. Here we study the dynamics of the hydrogen bond (HB) network
of a percolating layer of water molecules, comparing measurements of a hydrated
globular protein with the results of a coarse-grained model that has been shown
to successfully reproduce the properties of hydration water. With dielectric
spectroscopy we measure the temperature dependence of the relaxation time of
protons charge fluctuations. These fluctuations are associated to the dynamics
of the HB network of water molecules adsorbed on the protein surface. With
Monte Carlo (MC) simulations and mean--field (MF) calculations we study the
dynamics and thermodynamics of the model. In both experimental and model
analyses we find two dynamic crossovers: (i) one at about 252 K, and (ii) one
at about 181 K. The agreement of the experiments with the model allows us to
relate the two crossovers to the presence of two specific heat maxima at
ambient pressure. The first is due to fluctuations in the HB formation, and the
second, at lower temperature, is due to the cooperative reordering of the HB
network
Identification and density of ichthyoplankton in Laft Creeks (Hormuzgan province)
During a series of Ichthyoplankton survey from May 1998 to April 1999 Ichthyoplankton samples were collected at 12 stations in Laft creeks by 500 micron bongonet with oblique towing from bottom to water surface. Twenty-two families Ichthyoplanktons were identified (and two unidentified) during 12 months. Clupeiidae (31, 32%), gobiidae (26, 71%), scianidae (16, 55%), leiognathidae (11, 9%) were common and dominant families in all sampling stations. The creeks was divided in two branches: In east branch gobiidae (44.75%), clupeiidae (17.42%), scianida (13.5%) were more abundant than other families and in west branch clupeiidae (34.22%), gobiidae (23.77%), scianidae (16.34%) showed leiognathidae (13.26%) more abundance than other families, too. Some families e.g hemiramphidae, engrauilidae, blenidae, bothidae only occur in west branch, pleuronectidae family only occur in west branch. The highest density was found in winter season
USCID fourth international conference
Presented at the Role of irrigation and drainage in a sustainable future: USCID fourth international conference on irrigation and drainage on October 3-6, 2007 in Sacramento, California.Includes bibliographical references.Based on the shortage of water resources in Iran and the high evapotranspiration rate in Khuzestan region (2044 mm/year), an irrigation system on Estamaran palm tree in the Experimental Farm of Shahid Rajaee of Omidiyeh plain was conducted. This study had two purposes, namely irrigation frequency and suitable depth of irrigation application of the Estamaran palm trees in Omidiyeh region. This study had two objectives. Irrigation frequency was the primary treatment and the evapotranspiration estimating methods was the secondary treatment. Three irrigation levels. i.e. one day long (A1), two day long (A2) and three day long (A3), were used as irrigation frequency. Also the evapotranspiration estimating methods used were, Penman-Montith 100% (B1), Penman-Montith 70% (B2), class A pan 100% (B3) and class A pan 70% (B4). Since this study had three replications, 36 palm trees were selected for this experiment. Cropwat software V.4 for windows, was applied for the evapotranspiration estimating from Penman-Montieth method. Irrigation scheduling was done according to SCS recommendations. Experimental design was according to split plot method in a randomized block. Finally by measuring the different growth indices of palm trees (leaf number, barb number and leaflet length) at a definite time, the best treatment was determined. The results showed that as a whole all the treatments in this experiment did not show a significant difference (up to 5% level) for the indicated indices. However, at the end of 4 month since the beginning of this study, the growth indices of trees in A2B1, A1B2 and A1B1 increased compared to other treatments. The result also indicated that, A1B2 was the best treatment of all. In comparison with the traditional irrigation by local farmers, using A1B2 treatment for all the palm trees (from Aug to Nov), will have 28422.34 m3 water saving in 3.87 hectare per month
Privacy issues and protection in secure data outsourcing
Utilizing database encryption to safeguard data in several conditions where access control is not sufficient is unavoidable. Database encryption offers an extra layer of security to traditional access control methods. It stops users that are unauthorized, such as hackers breaking into a system, and observing private data. Consequently, data is safe even when the database is stolen or attacked. Nevertheless, the process of data decryption and encryption causes degradation in the database performance. In conditions where the entire information is kept in an encrypted format, it is not possible to choose the database content any longer. The data must be first decrypted, and as such, the unwilling and forced tradeoff occurs between the function and the security. The suitable methods to improve the function are techniques that directly deal with the data that is encrypted without having to decrypt them first. In this study, we determined privacy protection and issues that each organization should consider when it decides to outsource own data
Improved battery life for context awareness application in smart-phones
The new smart-phones with new operating system and portable sensors support the basis for context awareness systems and applications for handling user activity and user privacy. Nowadays, individuals need new services and real time information anywhere and anytime. Context awareness is an emerging service, which could be able to improve the user experiences in current situation. Context awareness can be considered as location, calendar, user activity and etc. The review of the literature proves that context awareness in mobile phone can be useful and studied as unavoidable service in next generation of smart-phone applications. In this paper, a short review about context awareness in mobile phone is studied, furthermore, we critically analyzed related works of context awareness in smart-phones. The review shows that the most important context in mobile phone is location, which is mostly obtained by using Global Positioning System (GPS) sensor in mobile phones but GPS can significantly increases battery consumption in mobile phones. In this regard, a framework as Improved Battery life in Context Awareness System (IBCS) is proposed to improve battery life and reduce cost of using GPS in context awareness applications based on smart-phones. The review argues the weakness and strength of these studies, and aims to (a) indicate the most important context in mobile phone, (b) reduce the battery consumption of GPS sensor in mobile phone
USCID fourth international conference
Presented at the Role of irrigation and drainage in a sustainable future: USCID fourth international conference on irrigation and drainage on October 3-6, 2007 in Sacramento, California.Includes bibliographical references.Backpropagation Neural Network is applied to establish the relationship between meteorological factors and evapotranspiration, which is then used to predict the evapotranspiration in ChiaNan irrigated area, Taiwan. It takes the weather data from Irrigation Experiment Station of ChiaNan Irrigation Association as the input layer, which include the following weather factors: (1) the highest temperature; (2) the lowest temperature; (3) average temperature; (4) relative humidity; (5) wind speed; (6) sunlight hours; (7) solar radiation amount; (8) dew point; (9) forenoon ground temperature; (10) afternoon ground temperature. From the result it can be known that the correlation coefficient reaches 0.993 between the evapotranspiration in 2004 calculated by FAO56 Penman-Monteith method and the one predicted by the neural network model with a hidden layer of 10 nodes. The actual evapotranspiration is 911.6cm and the prediction by the neural network is 864.4, between which the error ratio is 1.67%. The correlation coefficient is 0.708 between the actual evaporation in 2004 and the prediction by the neural network with a hidden layer of 10 nodes and an output layer with the pan evaporation as its target output. The pan evaporation is 1674.1cm, while the prediction by the neural network is 1451.7cm, between which the error ratio is 13.23%
A survey of algal bloom impacts on abundance and distribution of macro benthos in Hormozgan province coastal waters
The investigation of the algal bloom effects on Macro benthos abundance and diversity was seasonally carried out in coastline waters of Hormozgan province in 1391. Fourteen stations were selected for sampling; as 8 stations in coast of Bandar Abbas, 3 in Jask Port (east of Hormozgan) and 3 stations in Lengeh Port (west of Hormozgan). Polychaets, oligochaets, mollusks, crustacean and others like nematodes, nemertean’s, foraminifera’s, and ophiuroides were identified. Crustacean with 333950 ind.^-2 were dominant group whereas nemertean with 5050 ind.^-2 were minimum in density. Results showed that mean abundance of macro benthos was at most in spring (5614±3992 end) ^-2 and with 1244±380 ind.-2 was at least in autumn. Related results to stations showed that mean abundance in Jask Port and Lengeh Port were more than Bandar Abbas City. Among 8 stations in Bandar Abbas, Langargah with 168±977 ind.^ -2 was at most and Posht-e- shahr was at least in abundance (82±256 ind. ^-2). In Lengeh and Jask ports the stations far from coasts showed more abundance than station near coast. Monthly investigation showed that Macro benthos community was much more in April with 1011±6783 ind.-2 than December with 6±28 ind.^-2 , respectively. Shannon -Winner diversity index was low (0.61.2) in three stations, Evenness ranged from 0.1 to 0.4 and Margalof ranged from 2 to 4. Among four stations, mean wet weight varied from 12.18±6/95 gr in Jask Port (maximum) to 6.24±3/85gr in Bandar Abbas (minimum) .Seasonally, in spring the wet weight of macro benthos was 15.15±16/32 (maximum) and with 1.43±0.88 gr showed the minimum value in summer. There was a negative correlation between silt and macro benthos abundance and a positive correlation existed between macro benthos community and sand. There was no significant correlation between macro benthos community and TOM. To pay attention to results like diversity, abundance, wet biomass and correlation; it seems that algal bloom has no obvious negative effect on Macro benthos communities
Carbon combustion synthesis of Janus-like particles of magnetoelectric cobalt ferrite and barium titanate
Carbon combustion synthesis of oxides was applied for quick and energy efficient production of multiferroic composite of cobalt ferrite and barium titanate to form Janus-like particles matrix structure. The exothermic oxidation of carbon nanoparticles with an average size of 5 nm and a specific surface area of 110 m2/g generates a self-propagating thermal wave with peak temperature of up to 1000 °C. The thermal front rapidly propagates through the mixture of solid reactants (magnetic- CoFe2O4 and ferroelectric-BaTiO3) and results in localized hot-spot sintering of magneto-electric phases to form a nanocomposite structure. Carbon is not incorporated in the product and is emitted as a gaseous CO2. Existence of discrete CoFe2O4 and BaTiO3phases in the composites nanostructures was confirmed using X-ray powder diffraction along with SEM and TEM analysis. We estimated the activation energy for the combustion synthesis of Janus-like particles to be 112 ± 3.3 kJ/mol, indicating that the barium titanate and cobalt ferrite presence decrease the activation energy barrier of carbon oxidation and facilitate the ignition process of the combustion synthesis. We observe that the as-synthesized samples show magnetoelectric coupling on multiferroic cobalt ferrite–barium titanate ceramic composites
Determination of effective parameters on growth and bloom forming of Cochlodinium polykrikoides
Harmful algal blooms resulting in red discoloration of coastal waters in the Persian Gulf, Iran were first observed in January 2007. The species responsible for the bloom, which was identified as Cochlodinium polykrikoides, coincided with massive aquatic organisms’ mortalities in the Persian Gulf. In order to provide optimum growth and bloom forming, C. polykrikoides cells were sampled during the bloom conditions in the coastal waters of Persian Gulf. After adaptation in filtered seawater, they isolated by positive phototropism characteristic of this species to light. They were grown in modified media culture at different salinity (30, 32 and 35ppt), temperature (20, 23, 26 and 28ºC) and intensity (35, 70 and 90 µmol m^-2 s^-1) with an initial cell density of 50 cell mL^−1. The results of the present study clearly showed that the highest alga biomass was obtained following culture by using A^2 medium under the 32ppt salinity, 26°C temperature, and under a 11h light:13h dark photoperiod regime at a light intensity of 90 µmol m^-2 s^-1 provided by cool white fluorescent tubes. Mean cell density of C. polykrikoides in a 60 liter tank for ten days reached to 32 × 10^6 cell L^−1. Moreover, individual C. polykrikoides chain with 18 cells was observed for the first time in cultures. Based on the results from the present study, as mentioned above, providing suitable media culture and physical condition (light intensity and temperature), bloom forming of C. polykrikoides start from day 8 to 10 and will be continued until day 24 t0 28. In the other hand, C. polykrikoide cells immediately crashed and destroyed
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