排序方式: 共有122条查询结果,搜索用时 625 毫秒
31.
Eti Herman David Nicholas David Clark Chérifa Boukacem-Zeghmouri Blanca Rodríguez-Bravo Abdullah Abrizah David Sims Anthony Watkinson Jie Xu Galina Serbina Marzena Świgoń Hamid R. Jamali Carol Tenopir Suzie Allard 《Learned Publishing》2023,36(2):141-155
Presents findings from a study into the attitudes and practices of pandemic-era early career researchers (ECRs) in regard to obtaining access to the formally published scholarly literature, which focused on alternative providers, notably ResearchGate and Sci-Hub. The study is a part of the Harbingers project that has been exploring the work lives and scholarly communication practices of ECRs in pre-pandemic times and during the pandemic, and utilizes data from two rounds of interviews with around 170 ECRs from the sciences and social sciences in eight countries. Findings show that alternative providers, as represented by ResearchGate and Sci-Hub, have become established and appear to be gaining ground. However, there are considerable country- and discipline-associated differences. ECRs' country-specific level of usage of the alternative providers is partly traceable to the adequacy of library provisions, although there are other factors at play in shaping ECRs' attitudes and practices, most notably convenience and time saving, as well as the fact that these platforms have become embedded in the scholarly dashboard. There is a dearth of evidence of the impact of the pandemic on ECRs' ways of obtaining scholarly papers. 相似文献
32.
Sheikhattari P Stephenson R Assasi N Eftekhar H Zamani Q Maleki B Kiabayan H 《Child abuse & neglect》2006,30(3):231-245
OBJECTIVE: This study examines the determinants of three types of child maltreatment: physical maltreatment, mental maltreatment, and child neglect among school children in the Kurdistan Province of Iran. The analysis examines the impact of socioeconomic, familial, demographic, and household dynamic factors on the three child maltreatment outcomes, and compares the differential impact of these factors across the three types of child maltreatment. A greater understanding of the factors associated with child maltreatment has the potential to inform public health interventions aimed at reducing specific forms of maltreatment and at identifying at risk populations. METHODS: Data were collected from 1,370 school students, age 11-18. Separate logistic models are fitted for six binary outcomes examining self-reported experiences of physical maltreatment in the home or school, mental maltreatment in the home or school, and child neglect in the home or school. RESULTS: Male children were more likely to report experiencing any kind of child maltreatment than girls. Residency in a rural area, poor parental relationships and the use of addictive substances by household members were associated with increased odds of reporting child maltreatment. Poor school performance was associated with the reporting of experiencing maltreatment at school. CONCLUSION: Each of the forms of child maltreatment is highly correlated with socioeconomic, demographic, and living condition factors. The results point to the strong influence that familial factors have in shaping a child's likelihood of reporting maltreatment. Characteristics of the mother were associated with maltreatment, but not characteristics of the father. The results highlight a number of mechanisms through which public health interventions may seek to reduce the prevalence of child maltreatment in Kurdistan; different approaches are needed to reduce child maltreatment in the home and school environments. 相似文献
33.
David Nicholas Paul Huntington Bill Russell Anthony Watkinson Hamid R. Jamali Carol Tenopir 《Learned Publishing》2005,18(4):251-257
This paper describes the highlights of an exploratory deep log analysis of journal usage on OhioLINK, conducted as part of the MaxData project. OhioLINK, the original ‘Big Deal’, provides a single digital platform of nearly 6,000 full‐text journals for more than 600,000 people in Ohio and the investigation aimed to assess it after approximately 10 years. The data was generated from an SPSS analysis of the raw (unprocessed) server logs for June 2004 to December 2004. Approximately 1,215,000 items were viewed on campus in October 2004 and 1,894,000 items viewed off campus between June and December 2004. There are a number of usage analyses including: demand and activity; number and name of journal; date of publication; subject/discipline of journal and method of searching/navigating. 相似文献
34.
We analyse how the impact of determinants of inter-firm knowledge transfers in alliances can be moderated by the proximity of the resources pooled by partners. Six factors are examined: relative absorptive capacity (RAC), inter-partner trust, cultural distance between allies, knowledge ambiguity, knowledge protection, and the partners’ learning intent. We distinguish alliances mobilizing similar resources by partners (called ‘endogamies’ as allies build on their similarities) from alliances pooling different resources (called ‘exogamies’ as allies build on their differences). We propose that: (a) the impact of RAC on knowledge transfers is reinforced in exogamies, but reduced in endogamies; (b) the knowledge ambiguity and cultural distance effect is less in endogamies than in exogamies; (c) the trust and knowledge protection impact is stronger in exogamies than in endogamies; (d) the learning intent impact on knowledge transfers is similar in endogamies and exogamies. 相似文献
35.
Harisha Ramachandraiah Sahar Ardabili Asim M. Faridi Jesper Gantelius Jacob M. Kowalewski Gustaf M?rtensson Aman Russom 《Biomicrofluidics》2014,8(3)
Passive particle focusing based on inertial microfluidics was recently introduced as a
high-throughput alternative to active focusing methods that require an external force field to
manipulate particles. In inertial microfluidics, dominant inertial forces cause particles to move
across streamlines and occupy equilibrium positions along the faces of walls in flows through
straight micro channels. In this study, we systematically analyzed the addition of secondary Dean
forces by introducing curvature and show how randomly distributed particles entering a simple
u-shaped curved channel are focused to a fixed lateral position exiting the curvature. We found the
lateral particle focusing position to be fixed and largely independent of radius of curvature and
whether particles entering the curvature are pre-focused (at equilibrium) or randomly distributed.
Unlike focusing in straight channels, where focusing typically is limited to channel cross-sections
in the range of particle size to create single focusing point, we report here particle focusing in a
large cross-section area (channel aspect ratio 1:10). Furthermore, we describe a simple u-shaped
curved channel, with single inlet and four outlets, for filtration applications. We demonstrate
continuous focusing and filtration of 10 μm particles (with >90% filtration
efficiency) from a suspension mixture at throughputs several orders of magnitude higher than flow
through straight channels (volume flow rate of 4.25 ml/min). Finally, as an example of high
throughput cell processing application, white blood cells were continuously processed with a
filtration efficiency of 78% with maintained high viability. We expect the study will aid in the
fundamental understanding of flow through curved channels and open the door for the development of a
whole set of bio-analytical applications. 相似文献
36.
Mohammad Sadegh Cheri Hamidreza Shahraki Jalal Sadeghi Mohammadreza Salehi Moghaddam Hamid Latifi 《Biomicrofluidics》2014,8(5)
Measurement and control of pressure-driven flow (PDF) has a great potential to enhance the performance of chemical and biological experiments in Lab on a Chip technology. In this paper, we present an optofluidic flow sensor for real-time measurement and control of PDF. The optofluidic flow sensor consists of an on-chip micro Venturi and two optical Fabry-Pérot (FP) interferometers. Flow rate was measured from the fringe shift of FP interferometers resulted from movement fluid in the on-chip micro Venturi. The experimental results show that the optofluidic flow sensor has a minimum detectable flow change of 5 nl/min that is suitable for real time monitoring and control of fluids in many chemical and biological experiments. A Finite Element Method is used to solve the three dimensional (3D) Navier–Stokes and continuity equations to validate the experimental results. 相似文献
37.
Jing-qing Liu Zhi-feng Luo Ke Liu Yi-fu Zhang Hong-xi Peng Bao-lan Hu Hong-xing Ren Xiao-yan Zhou Shang-de Qiu Xiao-fang He Ping Ye Hamid Bastani Li-ping Lou 《浙江大学学报(A卷英文版)》2017,18(4):313-328
Biofilm detachment caused by flushing can result in secondary contamination in drinking water distribution systems (DWDSs). To evaluate the impact of flushing on biofilm detachment, actual water supply pipes including ductile cast iron pipes (DCIPs), gray cast iron pipes (GCIPs), and stainless steel compound pipes (SSCPs) were used in this study. Real-time quantitative polymerase chain reaction and 454 pyrosequencing were used to quantify bacteria and analyse microbial community composition, respectively. The results showed that the pipe material greatly influences the resistance of a biofilm to flushing. Biofilms attached to DCIPs were able to resist quite strong flushing, while those attached to GCIPs and SSCPs were sensitive to flushing. Both flush-resistant and flush-sensitive bacteria were present in all the biofilms, but their frequency differed among the different metal pipes. Thus, the resistance to flushing of bacteria is related not only to the nature of the bacteria, but also to the pipe material. Although flushing can remove some of the biofilm and may be a good way to clean the DWDS, the shear stress needed to remove the biofilm differs among different pipe types. The results of this study provide technical support for the management and operation of DWDS. 相似文献
38.
Nadeem Hera Malan Pieter Khan Amir Asif Mohd Ahmad Siddiqui Mansoor Tuhafeni Angombe Simon Ahmad Faheem 《Journal of Zhejiang University. Science. B》2021,22(7):563-574
This study focused, for the first time, on the effect of ultrasonic features on the extraction efficiency of secondary metabolites in mustard seed cake(MSC). The nematostatic potential of sonicated seed cake was examined against the second-stage juveniles(J2 s) of root-knot nematode, Meloidogyne javanica. The results show that a 35 ppm(parts per million) concentration of a sonicated extract(SE) sample of MSC caused 65% J2 s mortality at 18 h exposure period in vitro. It also significantly suppressed the root-knot index(RKI=0.94) in tomato roots. The lethal concentration values for SE were 51.76, 29.79, and 13.34 ppm,respectively, at 6, 12, and 18 h of the exposure period, and the lethal concentration values for the non-sonicated extract(NSE)sample were 116.95, 76.38, and 55.59 ppm, respectively, at similar exposure time. Sinapine and gluconapin were identified as the major compounds in ultrasonic-assisted MSC. Because of the high extraction efficiency of metabolites in the SE, all treatments of SE were shown to be antagonistic to J2 s. Thus, this study of ultrasonication activity-based profiling of MSC may help generate target-based compounds at a scale relevant to the control of disease caused by nematodes in economic crops. 相似文献
39.
Nina Sokolovic Andre Plamondon Michelle Rodrigues Sahar Borairi Michal Perlman Jennifer M. Jenkins 《Child development》2021,92(2):e143-e157
Are mother–child conflict discussions shaped by time-varying, reciprocal influences, even after accounting for stable contributions from each individual? Mothers were filmed discussing a conflict for 5 min, separately with their younger (ages 5–9, N = 217) and older (ages 7–13, N = 220) children. Each person’s conflict constructiveness was coded in 20-s intervals and data were analyzed using dynamic structural equation modeling, which separates individual and influence effects. Children influenced their mothers’ behavior under certain conditions, with evidence for developmental differences in the magnitude and direction of influence, whereas mothers did not influence their children under any circumstance. Results are discussed in the context of child effects on parent behavior and changes in parenting across middle childhood. 相似文献
40.
Lin Tang Wei-jun Luo Zhen-li He Hanumanth Kumar Gurajala Yasir Hamid Kiran Yasmin Khan Xiao-e Yang 《Journal of Zhejiang University. Science. B》2018,19(2):147-158
Vegetables are important constituents of the human diet. Heavy metals and nitrate are among the major contaminants of vegetables. Consumption of vegetables and fruits with accumulated heavy metals and nitrate has the potential to damage different body organs leading to unwanted effects. Breeding vegetables with low heavy metal and nitrate contaminants is a cost-effective approach. We investigated 38 water spinach genotypes for low Cd and nitrate co-accumulation. Four genotypes, i.e. JXDY, GZQL, XGDB, and B888, were found to have low co-accumulation of Cd (<0.71 mg/kg dry weight) and nitrate (<3100 mg/kg fresh weight) in the edible parts when grown in soils with moderate contamination of both Cd (1.10 mg/kg) and nitrate (235.2 mg/kg). These genotypes should be appropriate with minimized risk to humans who consume them. The Cd levels in the edible parts of water spinach were positively correlated with the concentration of Pb or Zn, but Cd, Pb, or Zn was negatively correlated with P concentration. These results indicate that these three heavy metals may be absorbed into the plant in similar proportions or in combination, minimizing the influx to aerial parts. Increasing P fertilizer application rates appears to prevent heavy metal and nitrate translocation to shoot tissues and the edible parts of water spinach on co-contaminated soils. 相似文献