Controls on the formation and sudden drainage of glacier-impounded lakes: implications for jökulhlaup characteristics

1999 ◽  
Vol 23 (1) ◽  
pp. 79-110 ◽  
Author(s):  
Fiona S. Tweed ◽  
Andrew J. Russell

Over the past few years there has been an increase in understanding of glacier-impounded or ‘ice-dammed’ lake behaviour. The spectacular jökulhlaup (catastrophic flood) from Grímsvötn, Iceland in November 1996 has both raised the profile of such events and emphasized the need for awareness of the processes involved. This review summarizes the extent of current knowledge of ice-dammed lakes, highlighting key developments and outlining areas of study still subject to difficulties. Controls on ice-dammed lake formation and persistence are identified, and cycles of jökulhlaup activity are related to glacier fluctuations. Ice-dammed lake drainage trigger mechanisms are reviewed and recent progress in the understanding of such mechanisms is emphasized. Controls on jökulhlaup routing and the development and character of jökulhlaup conduits are discussed and recent advances in jökulhlaup prediction, hydrograph modelling and peak discharge estimation are assessed. A process-based schematic model, drawing on published research, links ice-dammed lake occurrence and drainage to jökulhlaup characteristics. It is demonstrated that ice-dammed lake and ice-dam characteristics ultimately control seven key jökulhlaup attributes which determine the potential impact of jökulhlaups on both landscape and human activity in glaciated regions.

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 287
Author(s):  
Ye Lin Park ◽  
Kiwon Park ◽  
Jae Min Cha

Over the past decades, a number of bone tissue engineering (BTE) approaches have been developed to address substantial challenges in the management of critical size bone defects. Although the majority of BTE strategies developed in the laboratory have been limited due to lack of clinical relevance in translation, primary prerequisites for the construction of vascularized functional bone grafts have gained confidence owing to the accumulated knowledge of the osteogenic, osteoinductive, and osteoconductive properties of mesenchymal stem cells and bone-relevant biomaterials that reflect bone-healing mechanisms. In this review, we summarize the current knowledge of bone-healing mechanisms focusing on the details that should be embodied in the development of vascularized BTE, and discuss promising strategies based on 3D-bioprinting technologies that efficiently coalesce the abovementioned main features in bone-healing systems, which comprehensively interact during the bone regeneration processes.


2021 ◽  
Vol 10 (11) ◽  
pp. 2457
Author(s):  
Birgit J. Gerecke ◽  
Rolf Engberding

Noncompaction cardiomyopathy (NCCM) has gained increasing attention over the past twenty years, but in daily clinical practice NCCM is still rarely considered. So far, there are no generally accepted diagnostic criteria and some groups even refuse to acknowledge it as a distinct cardiomyopathy, and grade it as a variant of dilated cardiomyopathy or a morphological trait of different conditions. A wide range of morphological variants have been observed even in healthy persons, suggesting that pathologic remodeling and physiologic adaptation have to be differentiated in cases where this spongy myocardial pattern is encountered. Recent studies have uncovered numerous new pathogenetic and pathophysiologic aspects of this elusive cardiomyopathy, but a current summary and evaluation of clinical patient management are still lacking, especially to avoid mis- and overdiagnosis. Addressing this issue, this article provides an up to date overview of the current knowledge in classification, pathogenesis, pathophysiology, epidemiology, clinical manifestations and diagnostic evaluation, including genetic testing, treatment and prognosis of NCCM.


AI and Ethics ◽  
2021 ◽  
Author(s):  
Muhammad Ali Chaudhry ◽  
Emre Kazim

AbstractIn the past few decades, technology has completely transformed the world around us. Indeed, experts believe that the next big digital transformation in how we live, communicate, work, trade and learn will be driven by Artificial Intelligence (AI) [83]. This paper presents a high-level industrial and academic overview of AI in Education (AIEd). It presents the focus of latest research in AIEd on reducing teachers’ workload, contextualized learning for students, revolutionizing assessments and developments in intelligent tutoring systems. It also discusses the ethical dimension of AIEd and the potential impact of the Covid-19 pandemic on the future of AIEd’s research and practice. The intended readership of this article is policy makers and institutional leaders who are looking for an introductory state of play in AIEd.


2020 ◽  
Vol 12 (5) ◽  
pp. 1947 ◽  
Author(s):  
Philip Hallinger ◽  
Vien-Thong Nguyen

This systematic review of research used science mapping as a means of analyzing the knowledge base on education for sustainable development (ESD) in K-12 schooling. The review documented the size, growth trajectory and geographic distribution of this literature, identified high impact scholars and documents, and visualized the “intellectual structure” of the field. The database examined in this review consisted of 1842 English language, Scopus-indexed documents published between 1990 and 2018. The review found that the knowledge base on ESD has grown dramatically over the past 30 years, with a rapidly accelerating rate of publication in the past decade. Although the field has been dominated by scholarship from Anglo-American_European nations, there is evidence of increasing geographic diversification of the ESD knowledge base over the past 15 years. Citation analyses identified authors who have had a significant influence on the development of this literature. Author co-citation analysis revealed three “schools of thought” that comprise the “intellectual structure” of this knowledge base: Education for Sustainable Development, Developing a Sustainability Mindset, Teaching and Learning for Sustainability. Document content analyses led to the conclusion that the current knowledge base is heavily weighted towards critical, descriptive and prescriptive papers, with an insufficient body of analytical empirical studies. Several recommendations are offered for strengthening this literature.


2002 ◽  
Vol 15 (1) ◽  
pp. 125-144 ◽  
Author(s):  
Cees M. Verduin ◽  
Cees Hol ◽  
André Fleer ◽  
Hans van Dijk ◽  
Alex van Belkum

SUMMARY Moraxella catarrhalis (formerly known as Branhamella catarrhalis) has emerged as a significant bacterial pathogen of humans over the past two decades. During this period, microbiological and molecular diagnostic techniques have been developed and improved for M. catarrhalis, allowing the adequate determination and taxonomic positioning of this pathogen. Over the same period, studies have revealed its involvement in respiratory (e.g., sinusitis, otitis media, bronchitis, and pneumonia) and ocular infections in children and in laryngitis, bronchitis, and pneumonia in adults. The development of (molecular) epidemiological tools has enabled the national and international distribution of M. catarrhalis strains to be established, and has allowed the monitoring of nosocomial infections and the dynamics of carriage. Indeed, such monitoring has revealed an increasing number of Β-lactamase-positive M. catarrhalis isolates (now well above 90%), underscoring the pathogenic potential of this organism. Although a number of putative M. catarrhalis virulence factors have been identified and described in detail, their relationship to actual bacterial adhesion, invasion, complement resistance, etc. (and ultimately their role in infection and immunity), has been established in a only few cases. In the past 10 years, various animal models for the study of M. catarrhalis pathogenicity have been described, although not all of these models are equally suitable for the study of human infection. Techniques involving the molecular manipulation of M. catarrhalis genes and antigens are also advancing our knowledge of the host response to and pathogenesis of this bacterial species in humans, as well as providing insights into possible vaccine candidates. This review aims to outline our current knowledge of M. catarrhalis, an organism that has evolved from an emerging to a well-established human pathogen.


2016 ◽  
Vol 710 ◽  
pp. 409-414 ◽  
Author(s):  
Gianfranco De Matteis ◽  
Giuseppe Brando

This paper aims at providing an overview on the current state of the art and on possible future developments concerning the component method implementation for the classification of beam-to-column joints belonging to aluminum moment resisting frames.After a brief discussion on the component method theoretical bases, developed in the past to give a feasible calculation procedure for steel joints, recent experimental and numerical studies, carried out for investigating some aluminum components, are presented and discussed. In particular strengths and weaknesses of the current knowledge are put into evidence, also in light of the peculiarities that make aluminum alloys different from steel. The launch of new research fields, aimed at pursuing an update of the current codes dealing with aluminum structures, is therefore proposed.


Cancers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 604
Author(s):  
Laura Vanderwaeren ◽  
Rüveyda Dok ◽  
Kevin Verstrepen ◽  
Sandra Nuyts

Clinical use of proton radiation has massively increased over the past years. The main reason for this is the beneficial depth-dose distribution of protons that allows to reduce toxicity to normal tissues surrounding the tumor. Despite the experience in the clinical use of protons, the radiobiology after proton irradiation compared to photon irradiation remains to be completely elucidated. Proton radiation may lead to differential damages and activation of biological processes. Here, we will review the current knowledge of proton radiobiology in terms of induction of reactive oxygen species, hypoxia, DNA damage response, as well as cell death after proton irradiation and radioresistance.


PEDIATRICS ◽  
1973 ◽  
Vol 52 (4) ◽  
pp. 586-600
Author(s):  
David H. Smith ◽  
David L. Ingram ◽  
Arnold L. Smith ◽  
Floyd Gilles ◽  
M. J. Bresnan

Prior to the introduction of specific antibacterial therapy, bacterial meningitis was a disease with a universally fatal or disastrous outcome. The introduction of typespecific antiserum, and then of the antibacterial drugs, improved this situation dramatically. Improvements in the general medical care of acutely ill children, and the introduction of a series of more potent antibiotics against its bacterial causes helped to generate an attitude that bacterial meningitis was, or soon would be, a disease of the past. The experience of the past two decades belies this thesis. Today, interest in many facets of this disease has been renewed by many physicians concerned with the health of children: the epidemiology, pathophysiology, diagnosis, and treatment. This symposium attempts to summarize for the practitioner the highlights of current knowledge in this area, and to outline certain areas in which recent advances can be anticipated, or will be studied. Tuberculous meningitis will be omitted for the sake of brevity, as will the special problems of meningitis in the newborn infant. There has been a resurgence of interest in developing vaccines to prevent Hemophilus influenzae b, pneumococcal, and meningococcal Group A, B, and C meningitis. These organisms cause almost all the bacterial meningitis after the first two months of life. If, as now seems possible, vaccines against most or all of these organisms will soon become available, those children having the greatest risk must be defined to determine who, and at what age should have priority in receiving the vaccine(s). A. THE CURRENT MAGNITUDE OF THE PROBLEM


Author(s):  
PA Ganichev

Introduction: Polymer products have become inexpensive, convenient and widely used in all spheres of everyday life recently. Microplastics are found in seawater, wastewater, fresh water, foodstuffs, and air. Over the past few years, the presence of microplastics in treated tap and bottled water has been reported, raising questions and concerns about their potential human health effects. Objective: To summarize and systematize the results of studying health effects of exposure to microplastics in potable water. Materials and methods: A literature review was done based on ten topical articles and reviews published in 2014–2021 out of 64 sources found in the PubMed and Scopus international databases and the Russian Science Citation Index (RSCI). Results and conclusions: Generalization and systematization of the published research data demonstrated the lack of strong evidence to draw conclusions about human health effects of microplastics. Information on toxicokinetics and toxicodynamics of ingested microplastic particles is absent just like the studies of the most common shapes and sizes of plastic particles and health risks from exposure to such particles in drinking water.


2005 ◽  
Vol 29 (2) ◽  
pp. 139-155 ◽  
Author(s):  
Stefan Grab

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.


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