546 research outputs found
Surface runoff and phosphorus (P) loss from bamboo (Phyllostachys pubescens) forest ecosystem in southeast China
The effect of different fertilization treatments on runoff and nutrient losses under field conditions was investigated through setting runoff plots in bamboo (Phyllostachys pubescens) forests in a catchment of Taihu Lake. The results showed that, the runoff loss reached 356, 361 and 342 m3/hm2, while the soil particle loss reached 393, 392 and 442 kg/hm2, respectively, in the period from June 2009 to May 2010, under the treatments of control (CK), site-specific nutrient management (SSNM) and farmers’ fertilizer practice (FFP). The runoff and soil particle losses were highly correlated with the precipitation during the period. The largest phosphorus losses happened in August, when it had the largest rainfall of that year. The total phosphorus (TP) concentration of the 95% of the observed runoff samples exceeded 0.10 mg/l. The average bioavailable phosphorus (BAP) concentration of the runoff was 0.23 mg/l and the various phosphorus forms lost was strongly inter-correlated. Compared with FFP, the SSNM treatment reduced total P (TP) by 5%, total dissolved phosphorus (DP) loss by 15% and total bioavailable phosphorus (BAP) loss by 8%.Key words: Phyllostachys pubescens, ecosystem, surface runoff, phosphorus (P) loss
Effects of water temperature and migration time on some fecundity indices and fertilization rate of female Kutum, Rutilus frisii kutum,migratory to Shiroud River in the southwest Caspian Sea
Kutum, Rutilus frisii kutum, is an commercially important fish in the Caspian Sea. The fish enters the rivers leading to the Caspian Sea for spawning. One of these rivers is Shiroud River. In the artificial propagation process of Kutum, different factors are involved in quality and quantity of female broods eggs and also in the best temperature and migration time for spawning. The influence of temperature and migration time on some fecundity indices and fertilization rate of female kutum in Shiroud River was studied in the spawning season. In this study, 90 individual females were studied from February to May 2007. Averages of total length, weight and age were 43.26 cm, 832.08 g, and 4.41 respectively. Results showed that maximum egg diameter (1.86 mm), number of eggs per each gram of body weight (309.12), relative fecundity (56.21) and fertilization rate (95.82 %) were obtained from 5 to 20 April (15.95°C). Maximum ovary weight (201.00 g) and absolute fecundity of eggs (49987.18) were obtained from 6 to 20 March (17.74°C). Relationship between temperature and migration time and fecundity indices was linear and weak
Sensory texture of date fruits as a function of physicochemical properties and its use in date classification
Eight descriptive sensory textural attributes of whole date fruit were evaluated by twenty trained panel members and correlated with sixteen physicochemical properties. All sensory parameters, except gumminess, significantly correlated (Ps<0.05) with pectin, crude fibre, and moisture content. In addition, sensory hardness, cohesiveness, elasticity, and resilience correlated significantly with length of whole fruit (P<0.05), sensory adhesiveness with glucose content (P<0.05), sensory chewiness with mass of whole fruit (P<0.05), and sensory gumminess with fructose, glucose, and total sugar content (P<0.10). Sweetness, however, correlated only with moisture content (P<0.05). CA and the biplot (i.e. including all products, their sensory texture and physicochemical attributes) generated through PCA recognized three groups of dates as hard-chewy, soft-(medium-chewy), and soft-(non-adhesive)
Psychometric Properties of the Persian Version of Death Attitude Profile
Introduction: The type of human attitude toward death, as an unavoidable event, can affect the human approach to the themes of the worldly life and the afterlife. This study aimed to identify the factor structure of Persian version of Death Attitude Profile. Methods: In this descriptive survey research, 444 students of Jamia al-Zahra Seminary and Khomein Azad University, were selected by convenient sampling method. They responded to Persian version of the Death Attitude Profile. Results: Analysis of the findings indicated the Persian version of this profile, while deleting some items, supports the same 5-factor structure of the original form. Cronbach's alpha coefficient was 0.79 in the research sample. Conclusion: The obtained psychometric properties indicated the validity and reliability of this scale in Iranian society. Therefore, It can be used to measure the attitudinal properties of individuals to death. Declaration of Interest: None
Biosynthesis of Silver Nanoparticles from Desmodium triflorum: A Novel Approach Towards Weed Utilization
A single-step environmental friendly approach is employed to synthesize silver nanoparticles. The biomolecules found in plants induce the reduction of Ag+ ions from silver nitrate to silver nanoparticles (AgNPs). UV-visible spectrum of the aqueous medium containing silver ions demonstrated a peak at 425 nm corresponding to the plasmon absorbance of silver nanoparticles. Transmission electron microscopy (TEM) showed the formation of well-dispersed silver nanoparticles in the range of 5–20 nm. X-ray diffraction (XRD) spectrum of the AgNPs exhibited 2θ values corresponding to the silver nanocrystal. The process of reduction is extracellular and fast which may lead to the development of easy biosynthesis of silver nanoparticles. Plants during glycolysis produce a large amount of H+ ions along with NAD which acts as a strong redoxing agent; this seems to be responsible for the formation of AgNPs. Water-soluble antioxidative agents like ascorbic acids further seem to be responsible for the reduction of AgNPs. These AgNPs produced show good antimicrobial activity against common pathogens
Examining Dark Triad traits in relation to mental toughness and physical activity in young adults
Objective:
The Dark Triad (DT) describes a set of three closely related personality traits: Machiavellianism, narcissism, and psychopathy. Mental toughness (MT) refers to a psychological construct combining confidence, commitment, control, and challenge. High MT is related to greater physical activity (PA) and, relative to men, women have lower MT scores. The aims of the present study were 1) to investigate the association between DT, MT, and PA, and 2) to compare the DT, MT, and PA scores of men and women.
Methods:
A total of 341 adults (M=29 years; 51.6% women; range: 18–37 years) took part in the study. Participants completed a series of questionnaires assessing DT, MT, and PA.
Results:
Machiavellianism, narcissism, and psychopathy were all significantly associated with higher MT scores (rs =0.45, 0.50, and 0.20, respectively). DT traits and MT were associated with more vigorous PA. Compared to men, women participants had lower scores for DT traits (overall score and psychopathy), while no differences were found for MT or PA in both sexes.
Conclusion:
DT traits, high MT, and vigorous PA are interrelated. This pattern of results might explain why, for instance, successful professional athletes can at the same time be tough and ruthless
Promotion and updating of laboratories database for Iran Fisheries Research Organization
Creating a database of affiliated laboratories of the institute is organized with the aim of integrating information related to laboratories of research centers and their subsidiaries. The main objective of conducting this project in this stage is to upgrade it, establish and running one software system based on up-to-date technology of networking. In this way, in addition to organizing the centers database, a periodic report on various aspects can be done which help for implementing appropriate monitoring and management. Generally, the items that are designed and upgraded for this system include: Portal, bank of information, advanced possibilities for inputting data, searching and reporting on laboratory equipment and materials, information about calibration and repair and expiration dates of chemical materials, expertise and capabilities of personnel, providing laboratory services of institutes and research centers, direct order collecting of experiments from inside and outside of the institute, exchanging information, new test methods and sharing of new ideas and professional proposals, organizing laboratory materials, and exchange of expensive chemical materials. The advantages of this system compared to the previous version is that comprehensive, precise and updated reports can be collected easily from the general information of research institutes and centers, reports of the number of lab experts with different educational levels in affiliated centers, awareness of numbers and status of the chemical materials in the laboratories of each center, and the significant and important point is about economizing equipment, chemical materials and on time calibration, in time repairing of equipment and providing laboratories tariff and other matters
Contribution of Iran in COVID-19 studies: a bibliometrics analysis
Background: Iran is fighting heroically against COVID-19. Due to the importance of scientific publications in better dealing with this stubborn virus, this study was conducted aiming at reviewing COVID-19 publications by Iranian scientists. Methods: We searched for COVID-19 and all its related keywords in the Web of Science (WOS), Scopus and PubMed databases to find documents published by Iranian authors until July 10, 2020. Duplicates documents were excluded, and bibliographic parameters were evaluated. Co-authorship matrix was calculated using Bibexcel, and visualizations were done using VOSviewer. Results: A total of 849 documents from 3450 Iranian researchers (5.5 authors per document) were retrieved from WOS, PubMed, and Scopus and Iran ranked 12th and 13th in WOS and Scopus in terms of the number of publications. The average citation per document was 2.2 with the h-index of 18. Original articles and letters were the most common formats for Iranian publications. The Journal of Military Medicine has published the highest number of documents. Iranian authors have mostly collaborated with researchers from the United States, Italy, the UK, and Canada, respectively. The co-occurrence network for keywords represented five publication clusters in the collection, and the largest clusters were related to epidemiological studies and public health, followed by clinical studies on COVID-19. Conclusion: Iranian researchers have had a significant scientific contribution in various areas of the disease. However, the network of studies has not been sufficiently cohesive, and more coherent collaboration between researchers at the national and international levels should be on the agenda of research policymakers in the country
End-to-End Available Bandwidth Estimation Tools, An Experimental Comparison
Abstract. The available bandwidth of a network path impacts the per-formance of many applications, such as VoIP calls, video streaming and P2P content distribution systems. Several tools for bandwidth estimation have been proposed in the last years but there is still uncertainty in their accuracy and efficiency under different network conditions. Although a number of experimental evaluations have been carried out in order to compare some of these methods, a comprehensive evaluation of all the existing active tools for available bandwidth estimation is still missing. This article introduces an empirical comparison of most of the active esti-mation tools actually implemented and freely available nowadays. Abing, ASSOLO, DietTopp, IGI, pathChirp, Pathload, PTR, Spruce and Yaz have been compared in a controlled environment and in presence of dif-ferent sources of cross-traffic. The performance of each tool has been investigated in terms of accuracy, time and traffic injected into the net-work to perform an estimation.
ScreenTrack: Using a Visual History of a Computer Screen to Retrieve Documents and Web Pages
Computers are used for various purposes, so frequent context switching is
inevitable. In this setting, retrieving the documents, files, and web pages
that have been used for a task can be a challenge. While modern applications
provide a history of recent documents for users to resume work, this is not
sufficient to retrieve all the digital resources relevant to a given primary
document. The histories currently available do not take into account the
complex dependencies among resources across applications. To address this
problem, we tested the idea of using a visual history of a computer screen to
retrieve digital resources within a few days of their use through the
development of ScreenTrack. ScreenTrack is software that captures screenshots
of a computer at regular intervals. It then generates a time-lapse video from
the captured screenshots and lets users retrieve a recently opened document or
web page from a screenshot after recognizing the resource by its appearance. A
controlled user study found that participants were able to retrieve requested
information more quickly with ScreenTrack than under the baseline condition
with existing tools. A follow-up study showed that the participants used
ScreenTrack to retrieve previously used resources and to recover the context
for task resumption.Comment: CHI 2020, 10 pages, 7 figure
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