Negative, neutral, and positive interactions among nonnative plants: patterns, processes, and management implications

2014 ◽  
Vol 21 (2) ◽  
pp. 926-934 ◽  
Author(s):  
Sara E. Kuebbing ◽  
Martin A. Nuñez
1981 ◽  
Vol 12 (4) ◽  
pp. 216-232 ◽  
Author(s):  
Suzanne Evans Morris

The mealtime setting can be creatively used by the speech-language pathologist to increase the positive interactions between the child and caregiver and to establish the basic prerequisites for the development of communication. Specific program suggestions are provided to enable the speech-language pathologist to utilize the mealtime setting to integrate both vocal and nonvocal communicative objectives. The roots of interaction and communication which underly both vocal and nonvocal systems are described.


2003 ◽  
Vol 774 ◽  
Author(s):  
Janice L. McKenzie ◽  
Michael C. Waid ◽  
Riyi Shi ◽  
Thomas J. Webster

AbstractCarbon nanofibers possess excellent conductivity properties, which may be beneficial in the design of more effective neural prostheses, however, limited evidence on their cytocompatibility properties exists. The objective of the present in vitro study was to determine cytocompatibility and material properties of formulations containing carbon nanofibers to predict the gliotic scar tissue response. Poly-carbonate urethane was combined with carbon nanofibers in varying weight percentages to provide a supportive matrix with beneficial bulk electrical and mechanical properties. The substrates were tested for mechanical properties and conductivity. Astrocytes (glial scar tissue-forming cells) were seeded onto the substrates for adhesion. Results provided the first evidence that astrocytes preferentially adhered to the composite material that contained the lowest weight percentage of carbon nanofibers. Positive interactions with neurons, and, at the same time, limited astrocyte functions leading to decreased gliotic scar tissue formation are essential for increased neuronal implant efficacy.


1992 ◽  
Vol 26 (9-11) ◽  
pp. 2345-2348 ◽  
Author(s):  
C. N. Haas

A new method for the quantitative analysis of multiple toxicity data is described and illustrated using a data set on metal exposure to copepods. Positive interactions are observed for Ni-Pb and Pb-Cr, with weak negative interactions observed for Ni-Cr.


1995 ◽  
Vol 269 (4) ◽  
pp. R739-R748 ◽  
Author(s):  
C. De Rouffignac

The kidney is the main organ regulating composition of body fluids. A considerable number of hormones control the activity of renal cells to maintain hydromineral equilibrium. It becomes more and more difficult to interpret this multihormonal control in terms of regulatory processes. To illustrate this complexity, the hormonal regulation of electrolyte transport in the nephron thick ascending limb is taken as an example. This nephron segment is largely responsible for two kidney functions: the urinary-concentrating ability (by its capacity to deliver hypertonic sodium chloride into the medullary interstitium) and regulation of magnesium excretion into final urine. Six hormones are presently identified as acting on the transport of both sodium chloride and magnesium ions in this nephron segment. Therefore, the pertinent question is how the thick ascending limb and, hence, the kidney, is capable of regulating water balance independently from magnesium balance. It is proposed that the hormones act in combination: circulating levels of the individual hormones acting on these cells may determine the configuration of the paracellular and transcellular transport pathways of the epithelium either in the “sodium” or “magnesium” mode. The configuration would depend on the distribution and activity of the receptor at the surface of the basolateral membrane in contact with the circulating hormones. This distribution along with stimulation of respective signal transduction pathways would lead to the final biological effects. It is already known that the distribution of cell receptors may vary according to factors such as age, nutritional variability, hormonal status, degree of desensitization of the receptors, etc. The modulation of hormonal responses would depend therefore on the degree of coupling of hormone-receptor complexes to different intracellular transduction pathways and on the resulting negative and/or positive interactions between these pathways.


2020 ◽  
pp. 1-44
Author(s):  
CHRISTOF DEJUNG

Abstract This article examines the history of the Swiss merchant house Volkart Bros., which was one of the most important exporters of Indian raw cotton and one of the biggest trading firms in South Asia during the colonial period. The study allows for a fresh look at Indian economic history by putting forth two main arguments. First, it charts the history of a continental European firm that was active in South Asia to offer a better understanding of the economic entanglements of the subcontinent with the wider world, which often had a reach beyond the empire. This ties in with recent research initiatives that aim to examine the history of imperialism from a transnational perspective. Second, the history of a private company helps in developing a micro-perspective on the often ambiguous relation between the business goals of individual enterprises and colonial rule. The article argues that this may be evidence of the fact that capitalism and imperialism were two different, although sometimes converging, spatial structures, each with a distinct logic of its own. What is more, the positive interactions between European and Indian businessmen, fostered by a cosmopolitan attitude among business elites, point to the fact that even in the age of empire, the class background of actors could be more important for the establishing of cooperative ventures than the colour of their skin or their geographical origin. It is argued that this offers the possibility of examining the history of world trade in terms of global social history.


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