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151.
With the increase in urbanization globally, there is an increased need to understand the ecology of forest fragments in urban
and urbanizing landscapes. Although urban forests are known to be relatively lacking in plants whose seeds are dispersed by
ants, little is known about the effects of urbanization on the community composition and behaviour of forest dwelling ants.
Ant communities in forest fragments along an urban–rural gradient were described using a rapid quadrat search technique and
multivariate analysis. Interactions between the ants and seeds of the myrmecochorous Viola pubescens within a subset of these forests were described using a series of cafeteria experiments. Urbanization was found to be associated
with changes in microhabitat characteristics and a concomitant simplification of the ant community. Despite this, the removal
rate of V. pubescens seeds actually increased in urban forests, which may be a result of the foraging behaviour of the remaining species.
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Bill ThompsonEmail: |
152.
153.
Philip B. Holden Neil R. Edwards Paul H. Garthwaite Richard D. Wilkinson 《Journal of applied statistics》2015,42(9):2038-2055
Running complex computer models can be expensive in computer time, while learning about the relationships between input and output variables can be difficult. An emulator is a fast approximation to a computationally expensive model that can be used as a surrogate for the model, to quantify uncertainty or to improve process understanding. Here, we examine emulators based on singular value decompositions (SVDs) and use them to emulate global climate and vegetation fields, examining how these fields are affected by changes in the Earth's orbit. The vegetation field may be emulated directly from the orbital variables, but an appealing alternative is to relate it to emulations of the climate fields, which involves high-dimensional input and output. The SVDs radically reduce the dimensionality of the input and output spaces and are shown to clarify the relationships between them. The method could potentially be useful for any complex process with correlated, high-dimensional inputs and/or outputs. 相似文献
154.
This study assessed the utility of the Child Sexual Behavior Inventory (CSBI) in a child welfare sample. In this study, 97 children from ages 10 to 12 from either foster boarding homes or a residential treatment center participated. Researchers interviewed foster parents or primary therapists about children's sexual behavior, traumatic events, clinical symptoms, and their attitudes toward the child. Findings revealed that problematic sexualized behaviors were more prevalent in the residential treatment center (RTC) sample than they were in a normative sample. The pattern of associations between sexual behavior problems, traumatic events, and clinical syndromes in both the RTC and the foster boarding home (FBH) samples was similar to what has been found in samples in which biological custodial parents were the respondents. Analyses comparing youth who met the criterion for having problematic sexualized behaviors and youth who did not meet the criterion revealed that the two groups differed on clinical symptoms, prior traumatic events, and negative reports by caregivers. Results confirm the utility of the CSBI measure for this population and highlight several important clinical and programmatic concerns for addressing problematic sexual behavior in children in the child welfare system. 相似文献
155.
Bill Stone 《Child Abuse Review》1998,7(2):87-96
The research described here is an exploratory study of child neglect which focuses on practitioners' perspectives. The study was conducted in two stages. The first stage was a practitioner workshop from which data were obtained about perceptions of neglect. The second stage consisted of a sample survey of 20 cases registered in the category of neglect. Key workers of these cases were interviewed using semi-structured interview schedules based on material derived from the workshop. Major findings are that neglect is multifactorial and long term. Factors relating to parents/caregivers emerge as being integral to the way practitioners define neglect. Emotional/relational factors are seen to be central to practitioners' understandings of how children come to be neglected and the association between deprivation and neglect is underlined. © 1998 John Wiley & Sons, Ltd. 相似文献
156.
Performance measurement in industrial R&D 总被引:1,自引:0,他引:1
Currently, the need for R&D performance measurements that are both practically useful and theoretically sound seems to be generally acknowledged; indeed, the rising cost of R&D, greater emphasis on value management and a trend towards decentralization are escalating the need for ways of evaluating the contribution of R&D to corporate performance. However, although recent research and writing on the subject shows that the challenge of developing such sound measurements has been taken up by many academics and organizations, it is also clear that there is no generally applicable approach.
In this review, we consider various approaches for measuring the performance in industrial R&D and identify their key characteristics. We also include a brief summary of the 'history' of performance measurement in R&D, which shows that although there are some new ways of looking at the issue there are many examples from the past that can contribute to our current thinking.
The approaches found in the literature and practice are very varied in their application, some being more suitable for the project level, others for the R&D department, and some for the development process or for the organization as a whole. Furthermore, the uses of the approaches tend to be different. For example, some approaches are intended to justify the continuation of investment in R&D to upper management, whilst others are more suited to support learning and self-correction by empowered R&D teams. In this paper these uses, or 'functions', of performance measurement and a taxonomy of typical subjects of measurement in R&D environments are explored.
Finally, we conclude the review with a discussion of some limitations of the growing literature on R&D performance measurement. 相似文献
In this review, we consider various approaches for measuring the performance in industrial R&D and identify their key characteristics. We also include a brief summary of the 'history' of performance measurement in R&D, which shows that although there are some new ways of looking at the issue there are many examples from the past that can contribute to our current thinking.
The approaches found in the literature and practice are very varied in their application, some being more suitable for the project level, others for the R&D department, and some for the development process or for the organization as a whole. Furthermore, the uses of the approaches tend to be different. For example, some approaches are intended to justify the continuation of investment in R&D to upper management, whilst others are more suited to support learning and self-correction by empowered R&D teams. In this paper these uses, or 'functions', of performance measurement and a taxonomy of typical subjects of measurement in R&D environments are explored.
Finally, we conclude the review with a discussion of some limitations of the growing literature on R&D performance measurement. 相似文献
157.
VanDerhei J Holden S Alonso L 《EBRI issue brief / Employee Benefit Research Institute》2010,(350):1-67
CONSISTENT SAMPLE: Because 401(k) balances can fluctuate with market returns from year to year, meaningful analysis of 401(k) plans must examine how participants' accounts have performed over the long term. Looking at consistent participants in the EBRI/ICI 401(k) database over the six-year period from 2003 to 2009 (which included one of the worst bear markets for stocks since the Great Depression), the study found: After rising in 2003 and for the next four consecutive years, the average 401(k) retirement account fell 27.8 percent in 2008, before rising 31.9 percent in 2009. The average 401(k) account balance moved up and down with stock market performance, but over the entire six-year time period increased at an average annual growth rate of 10.5 percent, attaining $109,723 at year-end 2009. The median (or midpoint, half above and half below) 401(k) account balance increased at an average annual growth rate of 14.7 percent over the 2003-2009 period to $59,381 at year-end 2009. THE BULK OF 401(K) ASSETS CONTINUED TO BE INVESTED IN STOCKS: On average, at year-end 2009, 60 percent of 401(k) participants' assets were invested in equity securities through equity funds, the equity portion of balanced funds, and company stock. Thirty-six percent was in fixed-income securities such as stable-value investments and bond and money funds. MORE THAN THREE-QUARTERS OF 401(K) PLANS INCLUDED TARGET-DATE FUNDS IN THEIR INVESTMENT LINEUP AT YEAR-END 2009: At year-end 2009, nearly 10 percent of the assets in the EBRI/ICI 401(k) database was invested in target-date funds and 33 percent of 401(k) participants held target-date funds. Also known as lifecycle funds, they are designed to simplify investing and to automate account rebalancing. NEW EMPLOYEES CONTINUED TO USE BALANCED FUNDS, INCLUDING TARGET-DATE FUNDS: Across all but the oldest age group, more new or recent hires invested their 401(k) assets in balanced funds, including target-date funds. At year-end 2009, about 42 percent of the account balances of recently hired participants in their 20s were invested in balanced funds, compared with 36 percent in 2008, and about 7 percent in 1998. At year-end 2009, 31 percent of the account balances of recently hired participants in their 20s was invested in lifecycle funds, compared with almost 23 percent at year-end 2008. 401(K) PARTICIPANTS CONTINUED TO SEEK DIVERSIFICATION OF THEIR INVESTMENTS: The share of 401(k) accounts invested in company stock continued to shrink, falling by half of a percentage point (to 9.2 percent) in 2009. That continued a steady decline that started in 1999. Recently hired 401(k) participants contributed to this trend: They tended to be less likely to hold employer stock. PARTICIPANTS' 401(K) LOAN ACTIVITY ROSE IN 2009: In 2009, 21 percent of all 401(k) participants eligible for loans had a loan outstanding against their 401(k) account, compared with 18 percent at year-end 2008 and year-end 2007. Loans outstanding amounted to 15 percent of the remaining account balance, on average, at year-end 2009, compared with 16 percent at year-end 2008. Loan amounts remained in line with the past few years in terms of typical dollar amounts. 相似文献
158.
Bill Rocque 《Disability & Society》2010,25(4):485-497
Based on the findings of a qualitative study, this article describes how mothers of children labeled with autism spectrum disorder (ASD) mediate for their children in interactions with those who are unfamiliar with ASD. Data were collected through in‐depth interviews and participant observations. Findings indicate that mothers mediate for their children because they perceive hostility and lack of accommodation for their children on the part of unfamiliars. As they mediate, mothers attempt to construct and maintain positive identities for their children by explaining and reframing their children’s behaviors to influence the interpretations and responses of unfamiliars. I argue that in these interactions mothers function as proxy selves for their children because they are attempting to influence the perceptions others develop of their children, thus shaping their children’s social identity in the process. The findings of this study demonstrate the active, interpretive role that many mothers of children with autism play as they continually sort and assess information in order to determine what is in the best interests of their children. Further, the findings presented here demonstrate the social nature of self‐hood and identity, that all people involve others in the performance of their self‐hood. In this way and others, people labeled with ASD have much in common with those considered normal. 相似文献
159.
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