Effects of biotic and abiotic factors on forest biomass fractions     

Renfei Chen  Jinzhi Ran  Weigang Hu  Longwei Dong  Mingfei Ji  Xin Jia  Jingli Lu  Haiyang Gong  Muhammad Aqeel  Shuran Yao  Lizhe An  Jin-Sheng He  Karl J Niklas  Jianming Deng 《国家科学评论(英文版)》2021,8(10)

The extent to which key factors at the global scale influence plant biomass allocation patterns remains unclear. Here, we provide a theory about how biotic and abiotic factors influence plant biomass allocation and evaluate its predictions using a large global database for forested communities. Our analyses confirm theoretical predictions that temperature, precipitation, and plant height and density jointly regulate the quotient of leaf biomass and total biomass, and that they have a much weaker effect on shoot (leaf plus stem) biomass fractions at a global scale. Moreover, biotic factors have larger effects than abiotic factors. Climatic variables act equally on shoot and root growth, and differences in plant body size and age, as well as community species composition, which vary with climate in ways that drown out the variations in biomass fractions. The theory and data presented here provide mechanistic explanations of why climate has little effect on biomass fractions.  相似文献   

Relationships of Some Personality Variables to Academic Attainment of Secondary School Pupils     

Muhammad Maqsud 《教育心理学》1993,13(1):11-18

The study examined the relationship of extraversion (E), neuroticism (N), psychoticism (P), academic self‐concept and locus of control to academic attainment of lower secondary school pupils in a cross‐cultural context. Measures of E, N, P, academic self‐concept, locus of control and academic attainment were taken from 120 pupils (60 boys, 60 girls) of Standard 7 in a middle school in Bophuthatswana (Southern African region). The analysis of results revealed that E, N and P are significantly negatively related to academic attainment, while academic self‐concept and internality are significantly positively associated with measures of academic attainment. No significant sex differences were found. It was also observed that mean E and N scores of the subjects of this study were significantly lower than those given in Eysenck and Eysenck's (1975) normative data for English children of the same age.  相似文献   

The moderating role of intrinsic motivation in cloud computing adoption in online education in a developing country: a structural equation model     

Shahzad  Fakhar  Xiu  GuoYi  Khan  Imran  Shahbaz  Muhammad  Riaz  Muhammad Usman  Abbas  Adnan 《Asia Pacific Education Review》2020,21(1):121-141

Asia Pacific Education Review - In the provision of massive open online courses (MOOCs), cloud computing services enable students to synchronize their study materials anywhere, anytime, and using...  相似文献   

Microbial control of diamondback moth, Plutella xylostella L.(Lepidoptera:Yponomeutidae) using bacteria (Xenorhabdus nematophila) and its metabolites from the entomopathogenic nematode Steinernema carpocapsae     

MAHAR Ali Nawaz  MUNIR Muhammad  ELAWAD Sami  GOWEN Simon Richard  HAGUE Nigel Graham Meckenzi 《浙江大学学报(A卷英文版)》2004,5(10)

Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to larvae of the diamondback moth Plutella xylostella. Their application on leaves of Chinese cabbage indicated that the cells can penetrate into the insects in the absence of the nematode vector. Cell-free solutions containing metabolites were also proved as effective as bacterial cells suspension. The application of aqueous suspensions of cells of X. nematophila or solutions containing its toxic metabolites to the leaves represents a possible new strategy for controlling insect pests on foliage.  相似文献   

Mitigating the urban–rural educational gap in developing countries through mobile technology-supported learning     

Sharifullah Khan  Gwo-Jen Hwang  Muhammad Azeem Abbas  Arshia Rehman 《British journal of educational technology : journal of the Council for Educational Technology》2019,50(2):735-749

One form of educational inequality is the disparity that exists between urban and rural settings. Equal distribution of quality education is a challenge for developing countries due to the unavailability of resources. Various approaches to equal distribution are distance learning, telecast learning and e-learning; however, these approaches cannot achieve the desired objectives due to their limitations. This research aimed to investigate the interesting question of whether mobile technology can bring urban and rural settings closer together. A mobile application for learning Urdu grammar was designed to measure the learning gains of fourth-grade students at two different schools from urban and rural settings. A quantitative technique, the quasi-experimental pre-test and post-test method, was used to measure the effectiveness of the mobile application. The comparison of the students’ performances at the urban and rural schools illustrated the role of mobile technology in mitigating the educational gap. The present study provides evidence that children from different social backgrounds may benefit equally from mobile technology.  相似文献   

Using think-aloud protocols and interviews in investigating writers’ composing processes: combining concurrent and retrospective data     

Muhammad M. M. Abdel Latif 《International Journal of Research & Method in Education》2019,42(2):111-123

Research comparing the use of retrospective interviews (RIs) and think-aloud protocols (TAPs) as two data sources of writers’ composing processes is almost nonexistent. Trying to address this research gap, the present study examined the data obtained from the task-specific RIs and TAPs about the composing processes of 30 second language (L2) writers. Each participant thought aloud by concurrently verbalizing thoughts while performing an argumentative writing task, and then was interviewed immediately after the think-aloud session about their composing processes. The RI and TAP data was analyzed and compared in terms of five aspects of L2 writers’ composing: pre-writing stage, while-writing planning, first language (L1) use, composing problems and problem-solving, and text reviewing and changing. Though the results generally indicate that concurrent verbalizations provide much richer data than RIs about L2 writers’ composing processes, RIs were found to be a valuable source for revealing the ‘why’ of such processes. Besides, the gap between the data provided by the two sources differed from one composing aspect to another. Recommendations for how to optimally combine and make use of the two data sources in writing process research are provided.  相似文献   

Information Seeking Anxiety: Background,Research, and Implications     

Muhammad Asif Naveed 《International Information and Library Review》2017,49(4):266-273

This research aims to provide an analytic and critical review of research on information seeking anxiety (ISA) with a view to inform the information professionals, especially those engaged in information literacy instructions about the existing situation. This study established the background of the proposed phenomenon, provided integrated analysis of the available research, and discussed the theoretical and practical implications of ISA on information services, especially information literacy instruction. Although the results from previous studies were not comparable, directly due to varied geographical contexts and research methods, it was nevertheless possible to draw some common conclusions regarding the users’ anxiety related to information seeking tasks. This review overwhelmingly indicated the manifestation and prevalence of ISA among students in the digital environment. Some personal and academics variables of students appear to be correlated with ISA. The results of reviewed studies indicated the necessity for a need-based information literacy curriculum for alleviation of anxiety related to students’ information-seeking tasks.  相似文献   

Pakistani University Library Web Sites: Features,Contents, and Maintenance Issues     

Muhammad Abbas Ganaee  Muhammad Rafiq 《Journal of Web Librarianship》2016,10(4):294-315

ABSTRACT

This study explores the current status and features of Pakistan's academic library Web sites. A checklist describing features and content was prepared based on a review of the literature related to academic libraries’ Web sites. Then, all 85 library Web sites of Pakistani universities and degree-awarding institutions recognized by the Higher Education Commission (HEC) of Pakistan were surveyed and analyzed using the checklist. Interviews with library professionals were conducted to learn more about the problems and issues with building and maintaining library Web sites. Results indicate that Pakistani academic library Web sites have effective features such as contrasting color schemes, easily readable text, minimal use of horizontal scrolling, and English-language text. Staff information, OPACs, and navigation features are also widely found on the Web sites. Features found less frequently include the use of Web 2.0 technologies, Web site aid tools, information about library buildings, and general library information. By offering information about the status of Pakistani academic library Web sites, the study can serve as a foundation for discussion between libraries and other parts of the university, as well as a benchmark for evaluating the progress of academic library Web sites in Pakistan  相似文献   

Which US and European Higher Education Institutions are visible in ResearchGate and what affects their RG score?     

Benedetto Lepori  Michael Thelwall  Bareerah Hafeez Hoorani 《Journal of Informetrics》2018,12(3):806-818

While ResearchGate has become the most popular academic social networking site in terms of regular users, not all institutions have joined and the scores it assigns to academics and institutions are controversial. This paper assesses the presence in ResearchGate of higher education institutions in Europe and the US in 2017, and the extent to which institutional ResearchGate Scores reflect institutional academic impact. Most of the 2258 European and 4355 US higher educational institutions included in the sample had an institutional ResearchGate profile, with near universal coverage for PhD-awarding institutions found in the Web of Science (WoS). For non-PhD awarding institutions that did not publish, size (number of staff members) was most associated with presence in ResearchGate. For PhD-awarding institutions in WoS, presence in RG was strongly related to the number of WoS publications. In conclusion, a) institutional RG scores reflect research volume more than visibility and b) this indicator is highly correlated to the number of WoS publications. Hence, the value of RG Scores for institutional comparisons is limited.  相似文献   

Endophytes from medicinal plants and their potential for producing indole acetic acid,improving seed germination and mitigating oxidative stress     

Abdul Latif Khan  Syed Abdullah Gilani  Muhammad Waqas  Khadija Al-Hosni  Salima Al-Khiziri  Yoon-Ha Kim  Liaqat Ali  Sang-Mo Kang  Sajjad Asaf  Raheem Shahzad  Javid Hussain  In-Jung Lee  Ahmed Al-Harrasi 《Journal of Zhejiang University. Science. B》2017,18(2):125-137

Medicinal plants have been used by marginal communities to treat various ailments. However, the potential of endophytes within these bio-prospective medicinal plants remains unknown. The present study elucidates the endophytic diversity of medicinal plants (Caralluma acutangula, Rhazya stricta, and Moringa peregrina) and the endophyte role in seed growth and oxidative stress. Various organs of medicinal plants yielded ten endophytes, which were identified as Phoma sp. (6 isolates), Alternaria sp. (2), Bipolaris sp. (1), and Cladosporium sp. (1) based on 18S rDNA sequencing and phylogenetic analysis. The culture filtrates (CFs; 25%, 50%, and 100% concentrations) from these endophytes were tested against the growth of normal and dwarf mutant rice lines. Endophytic CF exhibited dose-dependent growth stimulation and suppression effects. CF (100%) of Phoma sp. significantly increased rice seed germination and growth compared to controls and other endophytes. This growth-promoting effect was due to the presence of indole acetic acid in endophytic CF. The gas chromatography/mass spectrometry (GC/MS) analysis showed the highest indole acetic acid content ((54.31±0.21) μmol/L) in Bipolaris sp. In addition, the isolate of Bipolaris sp. exhibited significantly higher radical scavenging and anti-lipid peroxidation activity than the other isolates. Bipolaris sp. and Phoma sp. also exhibited significantly higher flavonoid and phenolic contents. The medicinal plants exhibited the presence of bio-prospective endophytic strains, which could be used for the improvement of crop growth and the mitigation of oxidative stresses.  相似文献