Aspects of the geomorphology, genesis and environmental significance of earth hummocks (thúfur, pounus): miniature cryogenic mounds

2005 ◽  
Vol 29 (2) ◽  
pp. 139-155 ◽  
Author(s):  
Stefan Grab
Keyword(s):  
Current Knowledge ◽  
Thermal Characteristics ◽  
Environmental Research ◽  
Environmental Significance ◽  
Research Gaps ◽  
Frozen Ground ◽  
The Past ◽  
Internal Morphology ◽  
Differential Frost Heave ◽  
Made In

Miniature varieties of cryogenic mounds that are capable of forming in seasonally frozen ground are commonly referred to as earth hummocks (e.g., North America), thúfur (e.g., Greenland and Iceland) and pounus (Fennoscandia). Over the past few decades there has been a consistent interest to study earth hummocks from a variety of environmental settings. This review summarizes the current knowledge of earth hummocks, highlighting aspects on the external and internal morphology, and thermal characteristics, which may assist to explain hummock formation. Several hypotheses have been proposed for the genesis of earth hummocks, including the ‘cryoexpulsion’ of clasts, hydrostatic and cryostatic pressure, cellular circulation, and differential frost heave. These hypotheses are critically evaluated and some research gaps identified. It emerges that considerable advances have been made towards an improved understanding of earth hummock development, modification and disintegration. Much progress has been made in the application of earth hummock studies to a variety of environmental research approaches such as palaeoenvironmental reconstructions and assessing their impact on hillslope drainage.

scholarly journals Tooth Bioengineering and Regenerative Dentistry

2019 ◽  
Vol 98 (11) ◽  
pp. 1173-1182 ◽  
Author(s):  
P.C. Yelick ◽  
P.T. Sharpe
Keyword(s):  
Tissue Engineering ◽  
Current Knowledge ◽  
Basic Research ◽  
Dental Tissue ◽  
Dental Tissues ◽  
The Past ◽  
Tremendous Progress ◽  
Regenerative Dentistry ◽  
Dental Tissue Engineering ◽  
Made In

Over the past 100 y, tremendous progress has been made in the fields of dental tissue engineering and regenerative dental medicine, collectively known as translational dentistry. Translational dentistry has benefited from the more mature field of tissue engineering and regenerative medicine (TERM), established on the belief that biocompatible scaffolds, cells, and growth factors could be used to create functional, living replacement tissues and organs. TERM, created and pioneered by an interdisciplinary group of clinicians, biomedical engineers, and basic research scientists, works to create bioengineered replacement tissues that provide at least enough function for patients to survive until donor organs are available and, at best, fully functional replacement organs. Ultimately, the goal of both TERM and regenerative dentistry is to bring new and more effective therapies to the clinic to treat those in need. Very recently, the National Institutes of Health/National Institute of Dental and Craniofacial Research invested $24 million over a 3-y period to create dental oral and craniofacial translational resource centers to facilitate the development of more effective therapies to treat edentulism and other dental-related diseases over the next decade. This exciting era in regenerative dentistry, particularly for whole-tooth tissue engineering, builds on many key successes over the past 100 y that have contributed toward our current knowledge and understanding of signaling pathways directing natural tooth and dental tissue development—the foundation for current strategies to engineer functional, living replacement dental tissues and whole teeth. Here we use a historical perspective to present key findings and pivotal advances made in the field of translational dentistry over the past 100 y. We will first describe how this process has evolved over the past 100 y and then hypothesize on what to expect over the next century.

Impact of Different Leadership Styles of CEOs on Business Performance of SMEs in East Africa: A Systematic Review of Literature

2015 ◽  
Vol 4 (3) ◽  
Author(s):  
Tresphory Othumary Mgeni ◽  
Parameswar Nayak
Keyword(s):  
Leadership Styles ◽  
East Africa ◽  
Business Performance ◽  
Manufacturing Industries ◽  
Research Trend ◽  
Review Of Literature ◽  
Research Gaps ◽  
The Past ◽  
And Performance ◽  
Made In

This study attempts to review the prevailing body of literature on impacts of CEOs different leadership styles on business performance of SMEs in East Africa. The objective of this study is to identify the research trend in the area and issues that are currently addressed in East Africa so as to help interested researchers in the area. 130 relevant studies on the topic were systematically reviewed and the findings showed that, Asia has the leading number of studies published consistently within the past ten years followed by Europe and USA while Africa has the lowest number of studies. In addition, East Africa is among the regions which have the lowest number of studies in Africa. Most studies reviewed covered trade, service, and manufacturing industries. The findings varied from country to country and on the nature of the industry involved. Researchers in leadership and performance of SMEs are encouraged to bridge the research gaps established by this study such as researching in the particular area in industries and countries where no or few studies have been done. A special attention needs to be made in areas like East Africa and related regions which seem to have the lowest number of studies in the particular area.

Actinobacillus pleuropneumoniaevaccines: from bacterins to new insights into vaccination strategies

2008 ◽  
Vol 9 (1) ◽  
pp. 25-45 ◽  
Author(s):  
Mahendrasingh Ramjeet ◽  
Vincent Deslandes ◽  
Julien Gouré ◽  
Mario Jacques
Keyword(s):  
Bacterial Infections ◽  
Current Knowledge ◽  
Economic Losses ◽  
Swine Industry ◽  
Porcine Pleuropneumonia ◽  
Vaccination Strategies ◽  
The Past ◽  
Genomic Tools ◽  
Potential Vaccine ◽  
Made In

AbstractWith the growing emergence of antibiotic resistance and rising consumer demands concerning food safety, vaccination to prevent bacterial infections is of increasing relevance.Actinobacillus pleuropneumoniaeis the etiological agent of porcine pleuropneumonia, a respiratory disease leading to severe economic losses in the swine industry. Despite all the research and trials that were performed withA. pleuropneumoniaevaccination in the past, a safe vaccine that offers complete protection against all serotypes has yet not reached the market. However, recent advances made in the identification of new potential vaccine candidates and in the targeting of specific immune responses, give encouraging vaccination perspectives. Here, we review past and current knowledge onA. pleuropneumoniaevaccines as well as the newly available genomic tools and vaccination strategies that could be useful in the design of an efficient vaccine againstA. pleuropneumoniaeinfection.

The molecular biology of temperature-dependent sex determination

1995 ◽  
Vol 350 (1333) ◽  
pp. 297-304 ◽  
Keyword(s):  
Sex Determination ◽  
Molecular Basis ◽  
Current Knowledge ◽  
Temperature Dependent ◽  
The Past ◽  
Egg Incubation ◽  
Heteromorphic Sex Chromosomes ◽  
Substantial Progress ◽  
Common Molecular Basis ◽  
Made In

Many reptiles do not have heteromorphic sex chromosomes and for these species sex is determined during embryogenesis by the temperature of egg incubation rather than at conception. The phenomenon of temperature- dependent sex determination (TSD) was discovered almost thirty years ago, but few advances have been made towards the elucidation of its mechanism. In the past few years substantial progress has been made in the understanding of the molecular basis of XY chromosomal (genetic) sex determination (GSD) through the discovery of SRY. It is now possible to start comparing TSD with GSD. TSD is found in some evolutionarily ancient vertebrates and has been postulated to be the ancestral process from which GSD has evolved. If this is true then the two mechanisms may share a common molecular basis. This paper details the current knowledge of GSD, our progress on the investigation of the involvement of SRY-type proteins, and finally presents some of the problems that need to be resolved to gain an understanding of the molecular basis of TSD.

scholarly journals Mercury Exchange at the Air-Water-Soil Interface: An Overview of Methods

2002 ◽  
Vol 2 ◽  
pp. 1597-1602
Author(s):  
Fengman Fang ◽  
Qichao Wang ◽  
Ruhai Liu
Keyword(s):  
Soil Water ◽  
Current Knowledge ◽  
Terrestrial Ecosystems ◽  
Present Knowledge ◽  
Existing Problems ◽  
The Past ◽  
Emission Fluxes ◽  
Soil Interface ◽  
Soil And Water ◽  
Made In

An attempt is made to assess the present knowledge about the methods of determining mercury (Hg) exchange at the air-water-soil interface during the past 20 years. Methods determining processes of wet and dry removal/deposition of atmospheric Hg to aquatic and terrestrial ecosystems, as well as methods determining Hg emission fluxes to the atmosphere from natural surfaces (soil and water) are discussed. On the basis of the impressive advances that have been made in the areas relating to Hg exchange among air-soil-water interfaces, we analyzed existing problems and shortcomings in our current knowledge. In addition, some important fields worth further research are discussed and proposed.

scholarly journals Polysaccharide Biosynthesis: Glycosyltransferases and Their Complexes

2021 ◽  
Vol 12 ◽  
Author(s):  
Olga A. Zabotina ◽  
Ning Zang ◽  
Richard Weerts
Keyword(s):  
Protein Interactions ◽  
High Efficiency ◽  
Current Knowledge ◽  
Protein Protein Interactions ◽  
Acceptor Substrate ◽  
Plant Polysaccharide ◽  
Polysaccharide Biosynthesis ◽  
The Past ◽  
Genes Encoding ◽  
Made In

Glycosyltransferases (GTs) are enzymes that catalyze reactions attaching an activated sugar to an acceptor substrate, which may be a polysaccharide, peptide, lipid, or small molecule. In the past decade, notable progress has been made in revealing and cloning genes encoding polysaccharide-synthesizing GTs. However, the vast majority of GTs remain structurally and functionally uncharacterized. The mechanism by which they are organized in the Golgi membrane, where they synthesize complex, highly branched polysaccharide structures with high efficiency and fidelity, is also mostly unknown. This review will focus on current knowledge about plant polysaccharide-synthesizing GTs, specifically focusing on protein-protein interactions and the formation of multiprotein complexes.

Pronival ramparts

2016 ◽  
Vol 40 (6) ◽  
pp. 835-855 ◽  
Author(s):  
David W. Hedding
Keyword(s):  
Diagnostic Criteria ◽  
Environmental Indicators ◽  
Environmental Significance ◽  
Cold Environments ◽  
Exposure Dating ◽  
The Past ◽  
Field Identification ◽  
Modified Forms ◽  
Calibration Equations ◽  
Made In

Pronival ramparts are debris ridges formed at the downslope margins of perennial or semi-permanent snowbeds beneath bedrock cliffs. These landforms, also previously known as protalus ramparts, are located in periglacial environments, but the apparent simplicity of rampart formation made these landforms far less interesting than other modified forms of talus in cold environments. As a result, limited research, use of supposed relict examples and assumed formative mechanisms led to the misidentification of ramparts, circular arguments regarding genesis and inappropriate palaeo-environmental inferences. Several advances have, however, been made in the past few decades, particularly where actively-forming ramparts have been studied. Thus, this paper provides a review of research on pronival ramparts. In particular, focus is placed on the advances made in our understanding of rampart genesis, identification (diagnostic criteria) and palaeo-environmental significance. Notable advances include the development of a retrogressive model of rampart genesis to supplement the conventional downslope model of development, revised diagnostic criteria for field identification and the use of calibration equations during Schmidt-hammer exposure dating of pronival rampart. The use of pronival ramparts as palaeo-environmental indicators is also examined to determine what relict examples of these landforms may reveal about past climates.

South Asian Developmental Crisis (Review Article)

1973 ◽  
Vol 12 (2) ◽  
pp. 181-188
Author(s):  
Rafiq Ahmad
Keyword(s):  
Second World War ◽  
World War ◽  
The Past ◽  
The Great Depression ◽  
Political Independence ◽  
Integrated Theory ◽  
Pass Through ◽  
Developed World ◽  
Second World ◽  
Made In

Like nations and civilizations, sciences also pass through period of crises when established theories are overthrown by the unpredictable behaviour of events. Economics is passing through such a crisis. The challenge thrown by the Great Depression of early 1930s took a decade before Keynes re-established the supremacy of economics. But this supremacy has again been upset by the crisis of poverty in the vast under-developed world which attained political independence after the Second World War. Poverty had always existed but never before had it been of such concern to economists as during the past twenty five years or so. Economic literature dealing with this problem has piled up but so have the agonies of poverty. No plausible and well-integrated theory of economic development or under-development has emerged so far, though brilliant advances have been made in isolated directions.

Mass Spectrometry Techniques: Principles and Practices for Quantitative Proteomics

2020 ◽  
Vol 21 ◽  
Author(s):  
Rocco J. Rotello ◽  
Timothy D. Veenstra
Keyword(s):  
Mass Spectrometry ◽  
Quantitative Proteomics ◽  
Protein Identification ◽  
Dynamic Nature ◽  
Complete Coverage ◽  
The Past ◽  
Proteome Level ◽  
A Cell ◽  
Quantitative Changes ◽  
Made In

: In the current omics-age of research, major developments have been made in technologies that attempt to survey the entire repertoire of genes, transcripts, proteins, and metabolites present within a cell. While genomics has led to a dramatic increase in our understanding of such things as disease morphology and how organisms respond to medications, it is critical to obtain information at the proteome level since proteins carry out most of the functions within the cell. The primary tool for obtaining proteome-wide information on proteins within the cell is mass spectrometry (MS). While it has historically been associated with the protein identification, developments over the past couple of decades have made MS a robust technology for protein quantitation as well. Identifying quantitative changes in proteomes is complicated by its dynamic nature and the inability of any technique to guarantee complete coverage of every protein within a proteome sample. Fortunately, the combined development of sample preparation and MS methods have made it capable to quantitatively compare many thousands of proteins obtained from cells and organisms.

Evidence-based Assessment

2010 ◽  
pp. 76-98
Author(s):  
John Hunsley ◽  
Eric J. Mash
Keyword(s):  
Decision Making ◽  
Clinical Assessment ◽  
Assessment Process ◽  
Evidence Based ◽  
The Past ◽  
Specific Assessment ◽  
The Many ◽  
Selection Of ◽  
Made In

Evidence-based assessment relies on research and theory to inform the selection of constructs to be assessed for a specific assessment purpose, the methods and measures to be used in the assessment, and the manner in which the assessment process unfolds. An evidence-based approach to clinical assessment necessitates the recognition that, even when evidence-based instruments are used, the assessment process is a decision-making task in which hypotheses must be iteratively formulated and tested. In this chapter, we review (a) the progress that has been made in developing an evidence-based approach to clinical assessment in the past decade and (b) the many challenges that lie ahead if clinical assessment is to be truly evidence-based.

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