Human-Environmental Influences and Interactions in Shifting Agriculture When Farmers Form Expectations Rationally

1993 ◽  
Vol 25 (1) ◽  
pp. 121-136 ◽  
Author(s):  
D W Jones ◽  
R V O'Neill
Keyword(s):  
Interest Rates ◽  
Environmental Changes ◽  
Initial Period ◽  
Environmental Parameters ◽  
Land Rent ◽  
Fallow Period ◽  
Shifting Agriculture ◽  
Current Period ◽  
Expectations Formation ◽  
Future Value

This paper contains a study of the response of shifting agriculture to several social and environmental changes in circumstances in which farmers form in a relatively sophisticated manner their expectations of the future values of key economic variables. Farmers are ‘given’ a model of expectations formation in which the expected future value of variables interact in the same manner as in the current period. With this structure of expectations, the responses of the length of fallow period (the inverse of the percentage of available land cultivated in the initial period), the total area of land under cultivation and lying fallow in the initial period of a rotational cycle, and the initial-period wage rate and spatial structure of land rent to changes in several social and environmental parameters are examined. Several salient characteristics commonly attributed to shifting, or rotational, agriculture are replicated. Higher crop prices and increased population shorten fallow periods. Those same changes also increase the total area of land under shifting agriculture. Higher interest rates also shorten fallow periods. Fallows are longer at locations farther from central markets. Less commonly recognized is that social feedbacks operate to reduce pressure on more fragile land, although this does not imply that, other things being equal, fragile tropical land will not be ‘overused’ in an ecological sense.

scholarly journals Can the subterranean fauna be used as proxy for past environmental changes? – the example of the Carpathians cave fauna

2018 ◽  
Vol 1 ◽  
Author(s):  
Oana Teodora Moldovan ◽  
Ionut Cornel Mirea ◽  
Marius Kenesz
Keyword(s):  
Environmental Changes ◽  
Regional Scale ◽  
Environmental Parameters ◽  
General View ◽  
Carpathian Mountains ◽  
Small Areas ◽  
The Carpathians ◽  
Cave Fauna ◽  
Historical Processes ◽  
Geological Units

Carpathian Mountains were one of the main refuge areas during the climate changes of the Pleistocene and the Holocene in Europe and one of the richest regions in the world in subterranean (caves and associated habitats) endemic species. Nevertheless, the Carpathian Mountains subterranean fauna importance is underestimated especially due to dispersed information on its diversity and the scarcity of molecular studies in the area. Here, we present a first general view of the cave fauna hotspot represented by the Romanian Carpathians and the geological and historical processes that shaped the patterns of subterranean distribution and diversity at regional scale. The Carpathians are an amalgam of various geological units with complex paleogeographical evolution that is reflected in completely different species assemblages dominated by unit specific fauna groups. Phylogeography of Coleoptera and environmental parameters are adding to the general view at regional scale and offer additional explanation for this exceptional subterranean diversification in a non-Mediterranean region. We also use the example of the Carpathians cave fauna as proxy for past environmental changes in the area. Troglobionts are endemic on small areas and by studying their present distributions and phylogeny, past processes of landscape evolution on the surface can be better understood.

Diagnosis of the Operation of Power Plants

2007 ◽  
Author(s):  
Jose´ Miguel Gonza´lez-Santalo´ ◽  
Abigail Gonza´lez-Di´az ◽  
Carlos Alberto Marin˜o-Lo´pez
Keyword(s):  
Power Plants ◽  
Environmental Changes ◽  
Environmental Parameters ◽  
Combined Cycle ◽  
Characteristic Parameters ◽  
Operating Variables ◽  
Design Values ◽  
The Individual ◽  
The Impact

A system was developed to diagnose the operation of combined cycle power plants and to determine, when deviations are found, which components are causing the deviations and the impact of each component deviation. The system works by comparing the values of the actual operating variables with some reference values that are calculated by a model that was adjusted to the design heat balances. The model can use the actual values of the environmental parameters as well as the design values, so the effect of environmental changes can be quantified and separated. The determination of the individual equipment impacts is done by adjusting the equipment parameters in order to reproduce the values of the measured variables. The adjustment is done by varying the values of the characteristic parameters of the equipment in order to minimize the sum of the squares of the differences between the values of the measured variables and the calculated values from the model.

scholarly journals The Cell Membrane of Sulfolobus spp.—Homeoviscous Adaption and Biotechnological Applications

2020 ◽  
Vol 21 (11) ◽  
pp. 3935 ◽  
Author(s):  
Kerstin Rastädter ◽  
David J. Wurm ◽  
Oliver Spadiut ◽  
Julian Quehenberger
Keyword(s):  
Cell Membrane ◽  
Environmental Changes ◽  
Specific Growth ◽  
Membrane Lipids ◽  
Environmental Parameters ◽  
Coping Mechanism ◽  
Biotechnological Applications ◽  
Head Groups ◽  
Tetraether Lipids ◽  
Archaeal Lipids

The microbial cell membrane is affected by physicochemical parameters, such as temperature and pH, but also by the specific growth rate of the host organism. Homeoviscous adaption describes the process of maintaining membrane fluidity and permeability throughout these environmental changes. Archaea, and thereby, Sulfolobus spp. exhibit a unique lipid composition of ether lipids, which are altered in regard to the ratio of diether to tetraether lipids, number of cyclopentane rings and type of head groups, as a coping mechanism against environmental changes. The main biotechnological application of the membrane lipids of Sulfolobus spp. are so called archaeosomes. Archaeosomes are liposomes which are fully or partly generated from archaeal lipids and harbor the potential to be used as drug delivery systems for vaccines, proteins, peptides and nucleic acids. This review summarizes the influence of environmental parameters on the cell membrane of Sulfolobus spp. and the biotechnological applications of their membrane lipids.

scholarly journals The Impact of Climate Change on Cholera: A Review on the Global Status and Future Challenges

Atmosphere ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 449
Author(s):  
Eirini Christaki ◽  
Panagiotis Dimitriou ◽  
Katerina Pantavou ◽  
Georgios K. Nikolopoulos
Keyword(s):  
Climate Change ◽  
Environmental Changes ◽  
Natural Habitat ◽  
Environmental Parameters ◽  
Surveillance Systems ◽  
Educational Strategies ◽  
Global Status ◽  
Water Ecosystems ◽  
Sanitation Systems ◽  
The Impact

Water ecosystems can be rather sensitive to evolving or sudden changes in weather parameters. These changes can result in alterations in the natural habitat of pathogens, vectors, and human hosts, as well as in the transmission dynamics and geographic distribution of infectious agents. However, the interaction between climate change and infectious disease is rather complicated and not deeply understood. In this narrative review, we discuss climate-driven changes in the epidemiology of Vibrio species-associated diseases with an emphasis on cholera. Changes in environmental parameters do shape the epidemiology of Vibrio cholerae. Outbreaks of cholera cause significant disease burden, especially in developing countries. Improved sanitation systems, access to clean water, educational strategies, and vaccination campaigns can help control vibriosis. In addition, real-time assessment of climatic parameters with remote-sensing technologies in combination with robust surveillance systems could help detect environmental changes in high-risk areas and result in early public health interventions that can mitigate potential outbreaks.

scholarly journals Mechanism of Dissociation Kinetics in Polyelectrolyte Complex Micelles

2019 ◽  
Author(s):  
Hao Wu ◽  
Jeffrey Ting ◽  
Matthew Tirrell
Keyword(s):  
Light Scattering ◽  
Polyelectrolyte Complex ◽  
Environmental Changes ◽  
Environmental Parameters ◽  
Underlying Mechanism ◽  
Scattering Data ◽  
Relaxation Rates ◽  
Dissociation Kinetics ◽  
Complex Micelles ◽  
Kinetics Of

<div> <div> <p>Polyelectrolyte-based nanoscale self-assemblies, such as micelles, possess diverse desirable attributes such as capability for sequestering and protecting biomacromolecules against inhospitable environments, responsiveness to external stimuli, and tunability of physical behavior. However, little is known on the mechanisms of dissociation when micelles encounter and respond to environmental changes. Using salt-jump, time-dependent, light scattering, the pathway of dissociation is observed in polyelectrolyte complex micelles that have complex cores and neutral coronas. The micelle dissociation kinetics appear to be a three-staged process, in good agreement with the scattering data. Using kinetic models of amphiphilic block copolymer micelles in polyelectrolyte complexation-driven micelles, we derive an analytical expression for dissociation relaxation rates as a function of solvent temperature, salt concentration, and the length of the charged polymer blocks. The theoretical predictions are compatible with the experimental data from light scattering experiments. This study demonstrates experimentally the relaxation kinetics of polyelectrolyte complex micelle dissociation and illustrates the underlying mechanism governing the dissociation kinetics. It is anticipated that these findings can be generalized to other electrostatic interaction-driven self-assemblies to better understand the relationship among the kinetics of dissociation, constituent polymer properties, and environmental parameters.<br></p> </div> </div>

scholarly journals Reflections on Post-graduate education in Social Work in Brazil through the staff profile

2017 ◽  
Vol 20 (2) ◽  
pp. 155-164
Author(s):  
Maria Lúcia Teixeira Garcia ◽  
Vera Maria Ribeiro Nogueira
Keyword(s):  
Social Work ◽  
Graduate Education ◽  
Graduate Programs ◽  
Initial Period ◽  
Teaching Staff ◽  
Current Profile ◽  
Post Graduate ◽  
Current Period ◽  
Social Work Programs ◽  
Year 2000

Abstract This article addresses issues related to the staff of Post-Graduate programs in Social Work in Brazil. Initially, it traces a retrospective of Post-Graduate education in the country and describes the structure of Social Work in three moments: the initial period, through the 1970’s and 1980’s; the period of expansion, between 1990 and 2005; and the current period, between 2006 and 2016. It points out the impasses experienced by the first programs in relation to the lack of Doctors. Next, it presents the current profile of the professors who are part of Social Work programs. Data were obtained from CAPES, Geocapes and program reports, and analyzed through descriptive statistical analysis and content analysis. In conclusion, it evidences a growing tendency towards qualification and a marked expansion of the number of teaching staff after the year 2000. The growth of doctoral courses is noteworthy, however, the relation between teaching staff and students did not change significantly in percentage terms.

scholarly journals Progressive Microbial Community Networks with Incremental Organic Loading Rates Underlie Higher Anaerobic Digestion Performance

mSystems ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Linwei Wu ◽  
Xiaoyu Shan ◽  
Si Chen ◽  
Qiuting Zhang ◽  
Qi Qi ◽  
...  
Keyword(s):  
Methane Production ◽  
Environmental Changes ◽  
Matrix Theory ◽  
Biotic Interactions ◽  
Environmental Parameters ◽  
Microbial Interactions ◽  
Microbial Interaction ◽  
Organic Loading ◽  
Loading Rates ◽  
Vs Removal

ABSTRACT Although biotic interactions among members of microbial communities have been conceived to be crucial for community assembly, it remains unclear how changes in environmental conditions affect microbial interaction and consequently system performance. Here, we adopted a random matrix theory-based network analysis to explore microbial interactions in triplicate anaerobic digestion (AD) systems, which is widely applied for organic pollutant treatments. The digesters were operated with incremental organic loading rates (OLRs) from 1.0 g volatile solids (VS)/liter/day to 1.3 g VS/liter/day and then to 1.5 g VS/liter/day, which increased VS removal and methane production proportionally. Higher resource availability led to networks with higher connectivity and shorter harmonic geodesic distance, suggestive of more intense microbial interactions and quicker responses to environmental changes. Strikingly, a number of topological properties of microbial network showed significant (P < 0.05) correlation with AD performance (i.e., methane production, biogas production, and VS removal). When controlling for environmental parameters (e.g., total ammonia, pH, and the VS load), node connectivity, especially that of the methanogenic archaeal network, still correlated with AD performance. Last, we identified the Methanothermus, Methanobacterium, Chlorobium, and Haloarcula taxa and an unclassified Thaumarchaeota taxon as keystone nodes of the network. IMPORTANCE AD is a biological process widely used for effective waste treatment throughout the world. Biotic interactions among microbes are critical to the assembly and functioning of the microbial community, but the response of microbial interactions to environmental changes and their influence on AD performance are still poorly understood. Using well-replicated time series data of 16S rRNA gene amplicons and functional gene arrays, we constructed random matrix theory-based association networks to characterize potential microbial interactions with incremental OLRs. We demonstrated striking linkage between network topological features of methanogenic archaea and AD functioning independent of environmental parameters. As the intricate balance of multiple microbial functional groups is responsible for methane production, our results suggest that microbial interaction may be an important, previously unrecognized mechanism in determining AD performance.

scholarly journals The role of the hydrological cycle on the temporal patterns of macroinvertebrate assemblages in an Andean foothill stream in Colombia

2016 ◽  
Vol 75 (s1) ◽  
Author(s):  
María I. Ríos-Pulgarín ◽  
Mario Barletta ◽  
María C. Arango-Jaramillo ◽  
Néstor J. Mancera-Rodríguez
Keyword(s):  
El Niño ◽  
Environmental Changes ◽  
Hydrological Cycle ◽  
El Nino ◽  
Southern Oscillation ◽  
Environmental Parameters ◽  
Functional Feeding Groups ◽  
Feeding Groups ◽  
Hydrological Variability ◽  
Physical And Chemical

The seasonal and interannual changes in the structure, composition and functional feeding groups of the macroinvertebrate assemblage of the Guarinó River, a torrential system located in the Colombian Andean foothills, were examined in relation to the physical and chemical environmental changes associated with the hydrological cycle and the El Niño-Niña/Southern Oscillation (ENSO) between 2007 and 2010. Benthic samples were collected at three sites in the lower sections of the river. A total of 127 taxa were collected in the study, with the total taxonomic richness per site ranging from 82 to 96 taxa and benthos density averaging 5.41 ind. m<sup>-2</sup>. The density showed a tendency to decrease in periods of maximum river level and flow, particularly during La Niña phenomena, and to increase in dry periods, especially in the third year (2009-2010) during El Niño phenomena. The presence and abundance of taxa, functional feeding groups and life habits were regulated by environmental parameters associated with hydrological variability, derived of ENSO phenomena, especially flow rate values. The assemblage showed high taxonomic and functional diversity, which is characteristic of ecosystems affected by recurrent hydrological disturbances, exhibiting differentiated responses based on adaptive strategies against the local hydrologic regime that allow fast recovery under conditions like ENSO phenomena. Such responses include composition changes according to adaptations to different hydrological scenarios, the predominance of generalist trophic guilds and taxa with plasticity in their habits and range of environmental tolerance.

scholarly journals Comparison of the Effects of Environmental Parameters on Growth Rates of Vibrio vulnificus Biotypes I, II, and III by Culture and Quantitative PCR Analysis

2011 ◽  
Vol 77 (12) ◽  
pp. 4200-4207 ◽  
Author(s):  
Eva Chase ◽  
Valerie J. Harwood
Keyword(s):  
Quantitative Pcr ◽  
Growth Rates ◽  
Environmental Changes ◽  
Vibrio Vulnificus ◽  
Environmental Parameters ◽  
Defined Medium ◽  
Pcr Analysis ◽  
Human Pathogens ◽  
Content Type ◽  
Specific Growth Rates

ABSTRACTVibrio vulnificusis a natural inhabitant of estuarine waters. The three known biotypes include (i) most human pathogens, (ii) primarily eel pathogens, and (iii) pathogens associated with fish and with human wound infections in Israel. Despite the frequently lethal consequences ofV. vulnificusinfections, the growth rates of the various biotypes and their response to environmental changes are not well characterized. We compared the specific growth rates (μ) of a representative of each biotype by culture and quantitative PCR (qPCR) analysis in a defined medium under varied pH, temperature, and salinity. Growth rates based on culturable concentrations were always higher than those based on qPCR estimates; however, both enumeration methods yielded comparable results on the influence of environmental factors on growth rates. Temperature (25°C, 30°C, 37°C), pH (7.0, 8.0), and salinity (5 to 40‰) all had significant effects on the μ of each biotype. Temperature had the greatest effect on the μ of biotype 1 (CMCP6), whereas salinity had the greatest effect on the μ of biotypes 2 (ATCC 33147) and 3 (302/99). The biotypes' growth rates varied significantly; biotype 1 grew most rapidly, while biotype 3 grew most slowly. The highest growth rates were achieved at 37°C, pH 7.0, and salinities of 15 to 30‰ (μ = 4.0, 2.9, and 2.4 generations h−1for biotypes 1, 2, and 3, respectively). Other strains of the biotypes yielded comparable results, suggesting that the physiological responses of the biotypes are differentially affected by parameters that are highly variable both in estuarine environments and between the free-living and pathogen states ofV. vulnificus.

scholarly journals THE USE OF REMOTE SENSING, REGRESSION QUANTILES, AND GIS APPROACHES FOR MODELING OF SCALLOP LARVAE: A Case Study in Funka Bay, Hokkaido, Japan

2011 ◽  
Vol 6 (2) ◽  
pp. 191
Author(s):  
I Nyoman Radiarta
Keyword(s):  
Remote Sensing ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Environmental Changes ◽  
Monitoring Program ◽  
Environmental Parameters ◽  
Sea Surface ◽  
Remotely Sensed Data ◽  
Funka Bay ◽  
Scallop Larvae

In the development of scallop cultivation in Japan, larvae collection and propagation become an important factor. Although the monitoring program has been conducted, modeling of species distribution is becoming an important tool for understanding the effects of environmental changes and resources management. This study was conducted to construct a model for providing estimation of the scallop larvae distribution in Funka Bay, Hokkaido, Japan using the integration of remote sensing, Regression Quantile (RQ) and Geographic Information System (GIS)-based model. Data on scallop larvae were collected during one year spawning season from April to July 2003. Environmental parameters were extracted from multi sensor remotely sensed data (chlorophyll-a and sea surface temperature) and a hydrographic chart (water depth). These parameters together with larvae data were then analyzed using RQ. Finally, spatial models were constructed within a GIS by combining the RQ models with digital map of environmental parameters. The results show that the model was best explained by using only sea surface temperature. The highest larvae densities were predicted in a relatively broad distribution along with the shallow water regions (Toyoura and Sawara to Yakumo) and the deeper water areas (center of the bay). The spatial model built from the RQ provided robust estimation of the scallop larvae distributions in the study area, as confirmed by model validation using independent data. These findings could contribute on the monitoring program in this region in order to distinguish the potential areas for an effective spat collection.

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