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Non-normal real estate return distributions by property type in the U.K.
Investment risk models with infinite variance provide a better description of distributions of individual property returns in the IPD database over the period 1981 to 2003 than Normally distributed risk models, which mirrors results in the U.S. and Australia using identical methodology. Real estate investment risk is heteroscedastic, but the Characteristic Exponent of the investment risk function is constant across time yet may vary by property type. Asset diversification is far less effective at reducing the impact of non-systematic investment risk on real estate portfolios than in the case of assets with Normally distributed investment risk. Multi-risk factor portfolio allocation models based on measures of investment codependence from finite-variance statistics are ineffectual in the real estate context
The Effects of Private Self-Consciousness and Perspective Taking on Satisfaction in Close Relationships.
131 heterosexual student couples, aged 17â32 yrs, 30 of whom were married or engaged answered questions concerning themselves and their relationships. It was predicted that individual differences in private self-consciousness would be positively related to relationship satisfaction because of the greater self-disclosure resulting from that heightened self-attention. It was further predicted that individual differences in perspective taking would foster relationship satisfaction, independent of any influence of self-disclosure. Both expectations were confirmed. Scores on the private self-consciousness scale were predictive of reported self-disclosure, and self-disclosure was predictive of satisfaction in the relationship. Once the influence of self-disclosure was removed, no effect of self-consciousness on satisfaction remained. In contrast, after disclosure was controlled, perspective-taking scores were significantly related to satisfaction and were in fact unrelated to disclosure at all. Findings indicate that 2 personality characteristics having to do with habitual attention to behavioral tendencies, emotions, and motivations significantly enhance the quality of close heterosexual relationships in different ways
Review of \u3ci\u3eThe Midwestern Native Garden: Native Alternatives to Nonnative Flowers and Plants, An Illustrated Guide. \u3c/i\u3eBy Charlotte Adelman and Bernard L. Schwartz.
Native plants are important for maintaining biodiversity and supporting birds, mammals, and insects in a particular region. The interaction of plants with other organisms is what makes up food webs, and a shift in one will result in change in the other, change that is often detrimental to both. Invasive plant species, which include many nonnative types, can alter ecosystems with lasting effects on hydrology, nutrient cycling, and habitat. Similar to other regions, the Central Plains is increasingly threatened by the establishment of invasive plant species. The reintroduction of native plant species not only in large natural areas, but also in smaller settings such as home gardens, small pastures, and urban centers, will be critical in combating the advancement of invasive plant species. In The Midwestern Native Garden, Adelman and Schwartz set forth a simple and timely strategy for reducing invasive plant species: plant natives, thereby helping to restore critical ecosystem function in a range of settings. The book is ideal for plant enthusiasts, home gardeners, and anyone who manages landscapes in rural and urban areas of the Central Plains and neighboring regions. The authors have put together a list of nonnative and potentially invasive plants currently available at retail outlets and unknowingly used for display in private and public settings. For each nonnative plant, at least three to four native alternatives are suggested, along with written and pictorial information on plant characteristics and beneficial insects. Other key features that make the book especially useful are its notes, glossary, and bibliography sections, as well as a detailed index
Beyond Precision Weed Control: A Model for True Integration
Precision means being exact and accurate and is an important management component for cropping systems. However, precision does not mean integration, which encompasses spatial and temporal dimensions and is a necessary practice rivaling precision. True IWM merges precision and integration by incorporating advanced technology that allows for greater flexibility of inputs and enhanced responsiveness to field conditions. Examples of this approach are non-existent due to a lack of suitable technological tools and a need for a paradigm shift. Herein a potential model startup company is offered as a guide to advance beyond precision weed control to true integration. The critical components of such a company include grower connections, investor support, proven and reliable technology, and adaptability and innovation in the agricultural technology market. The company with the vision and incentive to make true IWM a reality will be the first to more fully integrate available tools using technology, thus helping many growers overcome ongoing challenges associated with resistance, soil erosion, drift, and weed seedbanks
What contributions are invasive plant species making to ecosystem services?
Invasive plant species can establish in diverse environments, and, with the increase in human mobility, they are no longer restricted to isolated pockets in remote parts of the world. Cheatgrass (Bromus tectorum L.) in rangelands, purple loosestrife (Lythrum salicaria L.) in wetlands, and tamarisk (Tamarix spp.) in riparian areas are examples of invasive plant species that are common to the United States and can be found in monocultures and patches covering many thousands of hectares. Across the world, invasive plant species like water hyacinth (Eichhornia crassipes), cogon grass (Imperata cylindrica), and mile-a-minute weed (Persicaria perfoliata L.) have choked waterways, altered fire regimes, or caused the abandonment of farmland due to their dominating andpersistent characteristics.
Clearly, the effects of invasive plant species have reached global scales and their related costs have been estimated in the billions of dollars (Pejchar and Mooney 2009). While the control of invasive plant species is warranted in many natural and man-made environments, these species do provide services to these ecosystems, which have yet to be quantified on a range of scales
Psychoanalytic approaches to qualitative psychology
The possible syncretism of contemporary social psychology and psychoanalysis has a number of facets, relating particularly to a shared concern with language or communication as the medium through which people compose themselves. The âaffective turnâ in the social sciences has opened this out still further, despite some radical criticisms of âsocial psychoanalysisâ developed therein. This chapter explores the issues involved in this âsyncretismâ and in the critiques, and examines practical issues around the deployment of notions such as reflexivity, transference and countertransference in research. We present an example from recent research on âbrotheringâ and argue both for the productivity of the application of psychoanalysis to qualitative material and for its problems. We argue that the use of psychoanalytic understanding must be tentative, rooted both in biographical information and in a dynamic contact with research participants that allows space for emotional connectedness and observation and thoughtful reflection on the relationship that arises. As with other forms of qualitative research, analysis of textual material must be rigorous and cautious, employing psychoanalytic concepts but grounding them in clearly observable textual moves âhowever open these might be to alternative readings as well
The Paper Trail: An Arid Connection & A Book of a Thousand Plants
Following my Ph.D., I moved on to Nebraska, where as a beginning faculty member I was able to start a research program in ecology and continue to study what intrigued me most: plant competition and stress. It was during this time that I came across the paper by Peter Alpert (see his article below) and his colleagues on âInvasiveness, invasibility, and the role of environmental stress in preventing the spread of non-native plantsâ (Perspectives in Plant Ecology, Evolution and Systematics 3:52â66). It was an âahaâ moment in reading about biological invasion research and the current consensus at that time regarding invasiveness and invasibility in plant species and communities. I had seen first-hand or at least I had thought about things like nonnatives remaining noninvasive for long periods, the relationship between plasticity and invasiveness, and the âunlike invaderâ hypothesis, which were all touched on in the paper. Add to this the discussion on the topic of stress (e.g., drought) affecting invasibility and the conceptual diagrams showing hypothetical responses of native and nonnatives under minimum and maximum levels, and I was convinced that my ideas were similar to those of others. For the first time, I did not feel alone in my thinking. In a way, it was a newfound freedom that allowed me to ponder more deeply the effects of stress on invasive plants. Extreme drought is a type of stress or selection pressure imposed on plants and communities of plants that can reveal fitness and plasticity differences that if understood could have profound impacts on invasion and community assembly theory
Invasion of Plant Communities
Due to numerous human activities, organisms have been transported and either accidentally or deliberately introduced all around the globe. Biological invasions are now considered to be one of the main drivers of global change because many invasive plants have severe ecological, economic, and health consequences. Thus, there is an ever-growing need to better understand invasions to determine how specific plant species are able to establish in communities and, in many cases, expand their range. Here, we describe the invasion process and how it contributes to the invasion of plant communities. We present an invasion-factor framework (IFF) model that uses three factors (climate dynamics, ecosystem resistance, and invader fitness) to explain how each plays a role in the introduction of plants and their ultimate failure or success (i.e., becoming invasive). The invasion of plant communities starts with the uptake of propagules from the native range, followed by their transport to and release into a new territory, where they become established and can spread or expand. Propagule pressure, prior adaptation, anthropogenically induced adaptation to invade, and post-introduction evolution are several theories that have been posed to explain the establishment of invasive plants. Further, traits of invasive plants, either before (existing) or after (developed) introduction, provide a mechanistic understanding with direct ties to the three factors of the IFF. The IFF is a general guide with which to study the invasion process based on specific factors for individual invaders and their target communities. The IFF combines (a) climatic dynamics, analogous to environmental filters; (b) ecosystem resistance, which prevents invasive plants from becoming established even if they are able to overcome the climate factor; and (c) invader fitness, relating to the genetic diversity of invasive plants, which allows them to become established after overcoming climate and ecosystem resistance factors. Case studies from the literature provide examples of research investigating each of the three factors of the IFF, but none exist that describe all the factors at once for any given invasive plant species. The application of the IFF for management is most appropriate once an invasive plant has become established, as preventative measures before this point rely only on accurate identification (detection) and removal (response). The IFF model should be considered as a tool to establish research priorities and identify components in the invasion process and inform restoration efforts. We advocate that the IFF should be integrated into management practices to help in the decision-making process that contributes to more effective practices that reduce the occurrence and impacts of invasive plants in a range of communities
Invasion during Extreme Weather: Success and Failure in a Temperate Perennial Grassland
Invasive and native plant species compete for resources in similar pools, with disturbances often favoring the invader. Yet, increased climate variability may be shifting the competitive edge back toward the natives. We conducted field studies in perennial grasslands to determine the effects of clipping and drought on resource availability (light and moisture) and subsequent establishment of Carduus nutans. We measured light penetration and soil moisture content in C. nutans monoculture, clipped and non clipped grassland with C. nutans, and bare ground control plots. We also tracked phenology of the invader and grasses. Our studies revealed that light was a limiting resource in normal precipitation years; removing biomass (e.g., clipped grassland plots) allowed C. nutans to successfully establish, while not removing biomass (e.g., nonclipped grassland plots) resulted in premature death. Similarly, soil moisture was a limiting resource when light was abundant; a lack of precipitation in the second year reduced grass growth, which opened the canopy and allowed adequate light for C. nutans seedlings that also died prematurely under extremely low soil moisture levels. We found that C. nutans was unable to compensate for the low light and soil moisture in offsetting, yet consecutive seasons and failed to establish in a nonclipped grassland. The emergence of C. nutans in a temperate perennial grassland is not a sure sign of success. Ifleft undisturbed, C. nutans seedlings may eventually die without having a significant impact on grasses
Invasion during Extreme Weather: Success and Failure in a Temperate Perennial Grassland
Invasive and native plant species compete for resources in similar pools, with disturbances often favoring the invader. Yet, increased climate variability may be shifting the competitive edge back toward the natives. We conducted field studies in perennial grasslands to determine the effects of clipping and drought on resource availability (light and moisture) and subsequent establishment of Carduus nutans. We measured light penetration and soil moisture content in C. nutans monoculture, clipped and non clipped grassland with C. nutans, and bare ground control plots. We also tracked phenology of the invader and grasses. Our studies revealed that light was a limiting resource in normal precipitation years; removing biomass (e.g., clipped grassland plots) allowed C. nutans to successfully establish, while not removing biomass (e.g., nonclipped grassland plots) resulted in premature death. Similarly, soil moisture was a limiting resource when light was abundant; a lack of precipitation in the second year reduced grass growth, which opened the canopy and allowed adequate light for C. nutans seedlings that also died prematurely under extremely low soil moisture levels. We found that C. nutans was unable to compensate for the low light and soil moisture in offsetting, yet consecutive seasons and failed to establish in a nonclipped grassland. The emergence of C. nutans in a temperate perennial grassland is not a sure sign of success. Ifleft undisturbed, C. nutans seedlings may eventually die without having a significant impact on grasses
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