Books on the topic 'Various pressure and temperature conditions'
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1
United States. National Aeronautics and Space Administration., ed. Droplet-turbulence interactions in sprays exposed to supercritical environmental conditions: Final report, NASA grant, #NAG8-160. [Washington, DC: National Aeronautics and Space Administration, 1993.
2
Manaa, M. Riad. Chemistry at extreme conditions. Amsterdam: Elsevier, 2005.
3
D, Hubbard Colin, and Eldik Rudi van, eds. Chemistry under extreme or non-classical conditions. New York: John Wiley, 1996.
4
United States. National Aeronautics and Space Administration., ed. SiC recession due to SiO₂ scale volatility under combustor conditions. Brook Park, Ohio: NYMA, Inc., 1997.
5
United States. National Aeronautics and Space Administration., ed. SiC recession due to SiO₂ scale volatility under combustor conditions. Brook Park, Ohio: NYMA, Inc., 1997.
6
Canada, Atomic Energy of. Chronology and Ambient Temperature/Pressure Conditions of Fluid Flow Through the Eye-Dashwa Lakes Pluton Based on the 18O/16O Ratio and Fluid Inclusions. S.l: s.n, 1985.
7
Pachurin, German. Technology for studying the destruction of structural materials under different loading conditions. ru: INFRA-M Academic Publishing LLC., 2021. http://dx.doi.org/10.12737/981296.
Abstract:
The textbook is devoted to solving topical issues related to the prediction of the effect of plastic deformation on the behavior in various operating conditions of a wide class of metals and alloys. The technology developed by the author for studying the mechanical properties and the process of destruction of plastically treated metal materials under various loading conditions (static at different temperatures, cyclic in air at low, room and elevated temperatures, as well as at room temperature in the presence of a corrosive environment) is described.
Meets the requirements of the federal state educational standards of higher education of the latest generation.
Addressed to bachelors and undergraduates of higher educational institutions of full-time and part-time education in the areas of training 20.03.01 Technosphere safety" (training profile "Safety of technological processes and production"), 22.03.01 and 22.04.01 "Materials Science and Materials Technology", 22.03.02 and 22.04.02 "Metallurgy", 15.03.01 and 15.04.01 "Mechanical Engineering", 15.05.01 "Design of technological machines and complexes", 15.03.02 "Technological machines and equipment", 15.03.04 and 15.04.04 "Automation of technological processes and production", 17.05.02 "Strelkovo-pushechnoe, artillery and rocket weapons", 15.03.05 "Design and technological support of machine-building industries". It can be useful for scientific and engineering workers of enterprises of automotive, aviation, shipbuilding and other metalworking branches of mechanical engineering, laboratory workers, as well as for training specialists in materials science, metal science and metal forming."
8
Technology for high pressure high temperature reservoir conditions. London: Bentham Press, 1995.
9
Jacobsen, Dean, and Olivier Dangles. The high altitude environment. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198736868.003.0001.
Abstract:
Chapter 1 gives a brief overview of the climatic and terrestrial environment in which high altitude waters are embedded. This context is necessary to understand the prevailing environmental conditions in the aquatic systems. The chapter begins by defining high altitude, alpine, and mountain, and provides an overview of the distribution of the world’s main high altitude regions. The overall picture of the climatic setting is drawn, from the inevitable consequences of high altitude (low temperature, low atmospheric pressure, and high solar radiation) to the highly region-specific patterns in precipitation and wind. The various ways that highland regions are formed, their temporal evolution, and climatic changes are treated in a section on the palaeo-environmental perspective. Finally, general patterns in high altitude (alpine) vegetation zones and treelines on different continents are synthesized, as well as major soil-forming processes in the catchments surrounding aquatic systems.
10
Droplet-turbulence interactions in sprays exposed to supercritical environmental conditions: Final report, NASA grant, #NAG8-160. [Washington, DC: National Aeronautics and Space Administration, 1993.
11
Droplet-turbulence interactions in sprays exposed to supercritical environmental conditions: Final report, NASA grant, #NAG8-160. [Washington, DC: National Aeronautics and Space Administration, 1993.
12
Advances in thin film thermocouple durability under high temperature and pressure testing conditions. [Cleveland, Ohio]: National Aeronautics and Space Administration, Lewis Research Center, 1999.
13
National Aeronautics and Space Administration (NASA) Staff. Advances in Thin Film Thermocouple Durability under High Temperature and Pressure Testing Conditions. Independently Published, 2018.
14
Krake, Ann M. Extremes of Temperature. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190662677.003.0014.
Abstract:
This chapter covers extremes of temperature conditions, physiological effects, and prevention. All deaths caused by exposure to hot and cold temperature extremes are preventable when proper measures are taken. Described in this chapter are the effects of extreme heat and extreme cold on the health of members of the public, particularly older people and young people, and workers employed in various workplace settings. The differences between heat stress and heat strain are also discussed, as are various regulations governing exposure to temperature extremes. The nature and magnitude of heat- and cold-related conditions and symptoms are described in detail. Final sections of the chapter address various assessment and evaluation tools as well as prevention and control measures. In addition, an appendix describes the hazards related to hyperbaric and hypobaric environments and adverse health effects.
15
van den Bosch, Annemien E., Luigi P. Badano, and Julia Grapsa. Right ventricle and pulmonary arterial pressure. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198726012.003.0023.
Abstract:
Right ventricular (RV) performance plays an important role in the morbidity and mortality of patients with left ventricular dysfunction, congenital heart disease, and pulmonary hypertension. Assessment of RV size, function, and haemodynamics has been challenging because of its complex geometry. Conventional two-dimensional echocardiography is the modality of choice for assessment of RV function in clinical practice. Recent developments in echocardiography have provided several new techniques for assessment of RV dimensions and function, include tissue Doppler imaging, speckle-tracking imaging, and volumetric three-dimensional imaging. However, specific training, expensive dedicated equipment, and extensive clinical validation are still required. Doppler methods interrogating tricuspid inflow and pulmonary artery flow velocities, which are influenced by changes in pre- and afterload conditions, may not provide robust prognostic information for clinical decision-making. This chapter addresses the role of the various echocardiographic modalities used to assess the RV and pulmonary circulation. Special emphasis has been placed on technical considerations, limitations, and pitfalls of image acquisition and analysis.
16
Jacobsen, Dean, and Olivier Dangles. Living conditions in high altitude waters. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198736868.003.0003.
Abstract:
Chapter 3 deals with the abiotic environment in high altitude lakes and streams worldwide. It searches for general patterns in relation to altitude, without overlooking the enormous variability, both temporally as well as at small and large spatial scales. Overall, environmental conditions in high altitude waters may be regarded as harsh. Indeed, certain features such as low temperature, low oxygen pressure, and high ultraviolet radiation (all a direct result of high altitude) as well as transparent and ion-poor waters with low nutrient concentrations are typical of high altitude aquatic systems. However, streams and lakes turbid from inflow of glacial meltwater loaded with glacial mineral flour and peatbogs with deep brown water from a high concentration of coloured dissolved organic matter are equally prominent. So, evidently, environmental conditions in aquatic systems are probably just as variable at high as at low altitudes.
17
Dunlop, Storm. 2. The circulation of the atmosphere. Oxford University Press, 2017. http://dx.doi.org/10.1093/actrade/9780199571314.003.0002.
Abstract:
‘The circulation of the atmosphere’ outlines the general model of the movement of air around the Earth. There are three circulation cells either side of the equator: the Hadley cell (nearest to the equator) and the polar cell, driven by specific temperature and pressure gradients, and the Ferrel cell between them. It describes global pressure patterns and the Coriolis effect, which results in south-westerly trade winds in the northern hemisphere and north-westerly trade winds in the southern. Also described are the Intertropical Convergence Zone, the polar easterlies, the westerlies, and how air moves around high- and low-pressure regions. The action of the surface winds also produces the various ocean currents.
18
Hasan, Rashid, and Shah Kabir. Fluid Flow and Heat Transfers in Wellbores. Society of Petroleum Engineers, 2018. http://dx.doi.org/10.2118/9781613995457.
Abstract:
Addressing both steady and unsteady-state fluid flow and related heat-transfer problems, the Second Edition of Fluid Flow and Heat Transfer in Wellbores strikes the perfect balance between theory and practice to aid understanding. Three new chapters on application of theory have been added and include probing pressure traverse in various wellbore multiphase fluid-flow situations, estimating flow rates from temperature data, translating off-bottom transient-pressure data to that at the datum depth, and a detailed discussion around newly discovered wellbore safety and integrity issues. Fundamental aspects of drilling, fluid circulation, and production operations form the foundation of this update of the 2002 original publication.
19
Kaufman, J. Gilbert, and Elwin L. Rooy. Aluminum Alloy Castings. ASM International, 2004. http://dx.doi.org/10.31399/asm.tb.aacppa.9781627083355.
Abstract:
Aluminum Alloy Castings: Properties, Processes and Applications is a practical guide to the process, structure, property relationships associated with aluminum alloy castings and casting processes. It covers a wide range of casting methods, including variations of sand casting, permanent mold casting, and pressure die casting, showing how key process variables affect the microstructure, properties, and performance of cast aluminum parts. Other chapters provide similar information on the effects of alloying and heat treating and the influence and control of porosity and inclusions. A significant portion of the book contains curated collections of property and performance data, including many previously unpublished aging response curves, growth curves, and fatigue curves; tensile properties at high and low temperatures and at room temperature after high-temperature exposure; the results of creep rupture tests conducted at temperatures from 212 to 600 °F (100 to 315 °C); and stress-strain curves obtained from casting alloys in various tempers under tensile or compressive loads. The book also discusses the factors that contribute to corrosion and fracture resistance and includes test specimen drawings as well as a glossary of terms. For information on the print version, ISBN 978-0-87170-803-8, follow this link.
20
Rau, Jochen. Constructing the State. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780199595068.003.0003.
Abstract:
The limited data available about a macroscopic system may come in various forms: sharp constraints, expectation values, or control parameters. While these data impose constraints on the state, they do not specify it uniquely; a further principle—the maximum entropy principle—must be invoked to construct it. This chapter discusses basic notions of information theory and why entropy may be regarded as a measure of ignorance. It shows how the state—called a Gibbs state—is constructed using the maximum entropy principle, and elucidates its generic properties, which are conveniently summarized in a thermodynamic square. The chapter further discusses the second law and how it is linked to the reproducibility of macroscopic processes. It introduces the concepts of equilibrium and temperature, as well as pressure and chemical potential. Finally, this chapter considers statistical fluctuations of the energy and of other observables in case these are given as expectation values.
21
North, Jill. Time in Thermodynamics. Edited by Craig Callender. Oxford University Press, 2011. http://dx.doi.org/10.1093/oxfordhb/9780199298204.003.0011.
Abstract:
It is often claimed, or hoped, that some temporal asymmetries are explained by the thermodynamic asymmetry in time. Thermodynamics, the macroscopic physics of pressure, temperature, volume, and so on, describes many temporally asymmetric processes. Heat flows spontaneously from hot objects to cold objects (in closed systems), never the reverse. More generally, systems spontaneously move from non-equilibrium states to equilibrium states, never the reverse. Delving into the foundations of statistical mechanics, this chapter reviews the many open questions in that field as they relate to temporal asymmetry. Taking a stand on many of them, it tackles questions about the nature of probabilities, the role of boundary conditions, and even the nature and scope of statistical mechanics.
22
Orenbuch-Harroch, Efrat, and Charles L. Sprung. Pulmonary artery catheterization in the ICU. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0133.
Abstract:
Haemodynamic monitoring is a significant component in the management of critically-ill patients. Flow-directed pulmonary artery catheters (PAC) are a simple and rapid technique for measuring several continuous or intermittent circulatory variables. The PAC is helpful in diagnosis, guidance of therapy, and monitoring therapeutic interventions in various clinical conditions, including myocardial infarction and its complications, non-cardiogenic pulmonary oedema and severely ill patients.The catheter is inserted through a large vein. The PAC is advanced, after ballooninflation with 1.5 mL of air, through the right ventricle across the pulmonary valve and into the pulmonary artery (PA). Finally, the catheter is advanced to the ‘wedge’ position. The pulmonary artery wedge pressure (PAWP) is identified by a decrease in pressure combined with a characteristic change in the waveform. The balloon should then be deflated and the PA tracing should reappear. Direct measurements include central venous pressure, pulmonary artery pressure, and PAWP, which during diastole represents the left ventricular end-diastolic pressure and reflects left ventricular preload. Cardiac output can be measured by thermodilution technique. Other haemodynamic variables can be derived from these measurements. Absolute contraindications are rare. Relative contraindications include coagulopathy and conditions that increase the risk of arrhythmias.
23
Clarke, Andrew. Energy and heat. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780199551668.003.0002.
Abstract:
Energy is the capacity to do work and heat is the spontaneous flow of energy from one body or system to another through the random movement of atoms or molecules. The entropy of a system determines how much of its internal energy is unavailable for work under isothermal conditions, and the Gibbs energy is the energy available for work under isothermal conditions and constant pressure. The Second Law of Thermodynamics states that for any reaction to proceed spontaneously the total entropy (system plus surroundings) must increase, which is why metabolic processes release heat. All organisms are thermodynamically open systems, exchanging both energy and matter with their surroundings. They can decrease their entropy in growth and development by ensuring a greater increase in the entropy of the environment. For an ideal gas in thermal equilibrium the distribution of energy across the component atoms or molecules is described by the Maxwell-Boltzmann equation. This distribution is fixed by the temperature of the system.
24
Naidech, Andrew M., ed. Neurocritical Care. Cambridge University Press, 2022. http://dx.doi.org/10.1017/9781108907682.
Abstract:
Events in a neurological intensive care unit are not always predictable and patients can often be unstable. This practical manual is a clear and concise guide for recognising and managing neurological emergencies. Each chapter covers a crucial topic in neurocritical care, from understanding the pathophysiology of various neurological diseases, to neuroradiology used in diagnosis, and best practice for difficult decision making in the ICU. A variety of conditions are described such as haemorrhage (intracerebral, subdural, and subarachnoid), seizures, trauma and temperature dysregulation. An international team of experts have contributed chapters, providing a breadth of experience and knowledge for readers. This is an invaluable guide for clinicians on the front line of caring for patients with neurological emergencies who need life-saving answers quickly.
25
Gidwani, Hitesh, and Chenell Donadee. Hypertensive Emergencies (DRAFT). Edited by Raghavan Murugan and Joseph M. Darby. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190612474.003.0009.
Abstract:
Hypertensive emergencies may be encountered by rapid response teams (RRTs). Various forms of acute organ dysfunction separate hypertensive urgency from hypertensive emergency. These include acute heart failure, acute coronary syndrome, acute aortic dissection, ischemic stroke, hemorrhagic stroke, hypertensive encephalopathy, sympathetic crisis, postoperative hypertension, and hypertensive emergencies in pregnancy. RRTs must be able to rapidly assess the patient’s condition, initiate treatment, and triage the patient to the appropriate level of care. This chapter summarizes the initial evaluation and triage of the patient as well as the blood pressure reduction goals in the acute period for the various conditions associated with hypertensive emergencies, discussing suggested drugs with the dosages, and looking at common pitfalls.
26
Laurent, Jose G. Cedeño, Joseph G. Allen, and John D. Spengler. The built environment and sleep. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198778240.003.0023.
Abstract:
Through evolution, our bodies have synchronized to environmental time, making our molecular clock mechanisms responsive to environmental cues such as light and temperature. In providing shelter from extreme climate conditions, however, modern societies have dramatically modified their environment without fully appreciating the consequences. We present an overview of the influence that lighting and thermal and acoustic conditions in our built environment exert on our sleep. These factors have changed substantially in the last century and biological systems have not had sufficient time to adapt. We also present a challenge for public health professionals: how to provide adequate sleeping conditions in low-income communities. We show how sleep quality is severely affected by socio-economic status, and illustrate how environmental injustice could exacerbate future challenges imposed by various climate change scenarios. We also discuss how technology could address these challenges in the built environment to promote conditions that foster good sleep and good health.
27
De Backer, Daniel, and Patrick Biston. Vasopressors in critical illness. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0034.
Abstract:
Vasopressors are used in various shock states to correct hypotension, aiming at restoring or improving organ and tissue perfusion. Vasopressor therapy may be associated with excessive vasoconstriction, but also metabolic and other side-effects. Hence, the ideal target for arterial pressure remains undetermined. Adrenergic agents remain the most commonly used vasopressor agents. Adrenergic agents increase arterial pressure through stimulation of alpha-adrenergic receptors. The effects of the different adrenergic agents differ mostly due to variable associated beta-adrenergic effects. Epinephrine and norepinephrine are strong and equipotent vasopressor agents. Their impact on outcome is as yet unanswered, but there is no sign that epinephrine might be associated with better outcomes. Accordingly, norepinephrine is the adrenergic agent of choice, especially in patients with cardiogenic shock. Vasopressin is a non-adrenergic vasopressor acting via V1 receptor stimulation, with weak vasopressor effects in normal conditions, but markedly increased vascular tone in shock states, especially in septic shock. Splanchnic vasoconstriction may occur. Arginine vasopressin at low doses appears to be a promising alternative to adrenergic agents, but its exact place is not yet well defined.
28
Schild, Laurent. Sodium transport and balance. Edited by Robert Unwin. Oxford University Press, 2015. http://dx.doi.org/10.1093/med/9780199592548.003.0021.
Abstract:
The kidney maintains the extracellular fluid volume and blood pressure by regulating urinary sodium (Na+) excretion to precisely balance daily Na+ intake. Genetic and experimental evidence support a central role for the distal nephron in the fine tuning of urinary Na+ excretion. The cellular and molecular aspects of the transporters involved in Na+ reabsorption in the distal nephron, and their regulation linked to complex signaling pathways are discussed. Na+ absorption can be viewed as a continuum in the activities of specific transport processes along the distal nephron. The crosstalk between these different and complex reabsorptive processes is important for the adaptation of Na+ excretion in various physiological, pathophysiological, and pharmacological conditions.
29
Busuioc, Aristita, and Alexandru Dumitrescu. Empirical-Statistical Downscaling: Nonlinear Statistical Downscaling. Oxford University Press, 2018. http://dx.doi.org/10.1093/acrefore/9780190228620.013.770.
Abstract:
This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Climate Science. Please check back later for the full article.The concept of statistical downscaling or empirical-statistical downscaling became a distinct and important scientific approach in climate science in recent decades, when the climate change issue and assessment of climate change impact on various social and natural systems have become international challenges. Global climate models are the best tools for estimating future climate conditions. Even if improvements can be made in state-of-the art global climate models, in terms of spatial resolution and their performance in simulation of climate characteristics, they are still skillful only in reproducing large-scale feature of climate variability, such as global mean temperature or various circulation patterns (e.g., the North Atlantic Oscillation). However, these models are not able to provide reliable information on local climate characteristics (mean temperature, total precipitation), especially on extreme weather and climate events. The main reason for this failure is the influence of local geographical features on the local climate, as well as other factors related to surrounding large-scale conditions, the influence of which cannot be correctly taken into consideration by the current dynamical global models.Impact models, such as hydrological and crop models, need high resolution information on various climate parameters on the scale of a river basin or a farm, scales that are not available from the usual global climate models. Downscaling techniques produce regional climate information on finer scale, from global climate change scenarios, based on the assumption that there is a systematic link between the large-scale and local climate. Two types of downscaling approaches are known: a) dynamical downscaling is based on regional climate models nested in a global climate model; and b) statistical downscaling is based on developing statistical relationships between large-scale atmospheric variables (predictors), available from global climate models, and observed local-scale variables of interest (predictands).Various types of empirical-statistical downscaling approaches can be placed approximately in linear and nonlinear groupings. The empirical-statistical downscaling techniques focus more on details related to the nonlinear models—their validation, strengths, and weaknesses—in comparison to linear models or the mixed models combining the linear and nonlinear approaches. Stochastic models can be applied to daily and sub-daily precipitation in Romania, with a comparison to dynamical downscaling. Conditional stochastic models are generally specific for daily or sub-daily precipitation as predictand.A complex validation of the nonlinear statistical downscaling models, selection of the large-scale predictors, model ability to reproduce historical trends, extreme events, and the uncertainty related to future downscaled changes are important issues. A better estimation of the uncertainty related to downscaled climate change projections can be achieved by using ensembles of more global climate models as drivers, including their ability to simulate the input in downscaling models. Comparison between future statistical downscaled climate signals and those derived from dynamical downscaling driven by the same global model, including a complex validation of the regional climate models, gives a measure of the reliability of downscaled regional climate changes.
30
Armstrong, Christopher. Climate Change and Justice. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190228637.013.231.
Abstract:
Understanding the complex set of processes collected under the heading of climate change represents a considerable scientific challenge. But it also raises important challenges for our best moral theories. For instance, in assessing the risks that climate change poses, we face profound questions about how to weigh the respective harms it may inflict on current and future generations, as well as on humans and other species. We also face difficult questions about how to act in conditions of uncertainty, in which at least some of the consequences of climate change—and of various human interventions to adapt to or mitigate it—are difficult to predict fully. Even if we agree that mitigating climate change is morally required, there is room for disagreement about the precise extent to which it ought to be mitigated (insofar as there is room for underlying disagreement about the level of temperature rises that are morally permissible). Finally, once we determine which actions to take to reduce or avoid climate change, we face the normative question of who ought to bear the costs of those actions, as well as the costs associated with any climate change that nevertheless comes to pass.
31
Özkul, Derya, and Hege Markussen, eds. The Alevis in Modern Turkey and the Diaspora. Edinburgh University Press, 2022. http://dx.doi.org/10.3366/edinburgh/9781474492027.001.0001.
Abstract:
This book explores the struggles of Alevis for recognition and representation in Turkey and the diaspora. It examines how Alevis mobilize against state practices and claim their rights, while at the same time negotiating how they define themselves. The authors offer a conceptual framework to study minorities by looking at both structural and agency-related factors in resisting state pressure and mobilizing for their rights. The Alevis in Modern Turkey and the Diaspora is divided into three main sections looking into: the Turkish state and society’s pressures over Alevis; how Alevis struggle and obtain representation in various Western countries; and how traditional authority and rituals transform under these conditions. Studying this group’s experience helps to understand oppression and resistance in the broader Middle East.
32
Bochaton-Piallat, Marie-Luce, Carlie J. M. de Vries, and Guillaume J. van Eys. Vascular smooth muscle cells. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780198755777.003.0007.
Abstract:
To understand the function of arteries in the regulation of blood supply throughout the body it is essential to realize that the vessel wall is composed predominantly of smooth muscle cells (SMCs) with only one single layer of luminal endothelial cells. SMCs determine the structure of arteries and are decisive in the regulation of blood flow. This review describes the reason for the large variation of SMCs throughout the vascular tree. This depends on embryonic origin and local conditions. SMCs have the unique capacity to react to these conditions by modulating their phenotype. So, in one situation SMCs may be contractile in response to blood pressure, in another situation they may be synthetic, providing compounds to increase the strength of the vascular wall by reinforcing the extracellular matrix. This phenotypic plasticity is necessary to keep arteries functional in fulfilling the metabolic demands in the various tissues of the body.
33
Donaghy, Michael. Focal peripheral neuropathy. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780198569381.003.0487.
Abstract:
Some causes of focal peripheral nerve damage are self-evident, such as involvement at sites of trauma, tissue necrosis, infiltration by tumour, or damage by radiotherapy. Focal compressive and entrapment neuropathies are particularly valuable to identify in civilian practice, since recovery may follow relief of the compression. Leprosy is a common global cause of focal neuropathy, which involves prominent loss of pain sensation with secondary acromutilation, and requires early antibiotic treatment. Mononeuritis multiplex due to vasculitis requires prompt diagnosis and immunosuppressive treatment to limit the severity and extent of peripheral nerve damage. Various other medical conditions, both inherited and acquired, can present with focal neuropathy rather than polyneuropathy, the most common of which are diabetes mellitus and hereditary liability to pressure palsies. A purely motor focal presentation should raise the question of multifocal motor neuropathy with conduction block, which usually responds well to high-dose intravenous immunoglobulin infusions.
34
Vuorinen, Ilppo. Post-Glacial Baltic Sea Ecosystems. Oxford University Press, 2018. http://dx.doi.org/10.1093/acrefore/9780190228620.013.675.
Abstract:
Post-glacial aquatic ecosystems in Eurasia and North America, such as the Baltic Sea, evolved in the freshwater, brackish, and marine environments that fringed the melting glaciers. Warming of the climate initiated sea level and land rise and subsequent changes in aquatic ecosystems. Seminal ideas on ancient developing ecosystems were based on findings in Swedish large lakes of species that had arrived there from adjacent glacial freshwater or marine environments and established populations which have survived up to the present day. An ecosystem of the first freshwater stage, the Baltic Ice Lake initially consisted of ice-associated biota. Subsequent aquatic environments, the Yoldia Sea, the Ancylus Lake, the Litorina Sea, and the Mya Sea, are all named after mollusc trace fossils. These often convey information on the geologic period in question and indicate some physical and chemical characteristics of their environment. The ecosystems of various Baltic Sea stages are regulated primarily by temperature and freshwater runoff (which affects directly and indirectly both salinity and nutrient concentrations). Key ecological environmental factors, such as temperature, salinity, and nutrient levels, not only change seasonally but are also subject to long-term changes (due to astronomical factors) and shorter disturbances, for example, a warm period that essentially formed the Yoldia Sea, and more recently the “Little Ice Age” (which terminated the Viking settlement in Iceland).There is no direct way to study the post-Holocene Baltic Sea stages, but findings in geological samples of ecological keystone species (which may form a physical environment for other species to dwell in and/or largely determine the function of an ecosystem) can indicate ancient large-scale ecosystem features and changes. Such changes have included, for example, development of an initially turbid glacial meltwater to clearer water with increasing primary production (enhanced also by warmer temperatures), eventually leading to self-shading and other consequences of anthropogenic eutrophication (nutrient-rich conditions). Furthermore, the development in the last century from oligotrophic (nutrient-poor) to eutrophic conditions also included shifts between the grazing chain (which include large predators, e.g., piscivorous fish, mammals, and birds at the top of the food chain) and the microbial loop (filtering top predators such as jellyfish). Another large-scale change has been a succession from low (freshwater glacier lake) biodiversity to increased (brackish and marine) biodiversity. The present-day Baltic Sea ecosystem is a direct descendant of the more marine Litorina Sea, which marks the beginning of the transition from a primeval ecosystem to one regulated by humans. The recent Baltic Sea is characterized by high concentrations of pollutants and nutrients, a shift from perennial to annual macrophytes (and more rapid nutrient cycling), and an increasing rate of invasion by non-native species. Thus, an increasing pace of anthropogenic ecological change has been a prominent trend in the Baltic Sea ecosystem since the Ancylus Lake.Future development is in the first place dependent on regional factors, such as salinity, which is regulated by sea and land level changes and the climate, and runoff, which controls both salinity and the leaching of nutrients to the sea. However, uncertainties abound, for example the future development of the Gulf Stream and its associated westerly winds, which support the sub-boreal ecosystems, both terrestrial and aquatic, in the Baltic Sea area. Thus, extensive sophisticated, cross-disciplinary modeling is needed to foresee whether the Baltic Sea will develop toward a freshwater or marine ecosystem, set in a sub-boreal, boreal, or arctic climate.
35
Dussaule, Jean-Claude, Martin Flamant, and Christos Chatziantoniou. Function of the normal glomerulus. Edited by Neil Turner. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199592548.003.0044_update_001.
Abstract:
Glomerular filtration, the first step leading to the formation of primitive urine, is a passive phenomenon. The composition of this primitive urine is the consequence of the ultrafiltration of plasma depending on renal blood flow, on hydrostatic pressure of glomerular capillary, and on glomerular coefficient of ultrafiltration. Glomerular filtration rate (GFR) can be precisely measured by the calculation of the clearance of freely filtrated exogenous substances that are neither metabolized nor reabsorbed nor secreted by tubules: its mean value is 125 mL/min/1.73 m² in men and 110 mL/min/1.73 m² in women, which represents 20% of renal blood flow. In clinical practice, estimates of GFR are obtained by the measurement of creatininaemia followed by the application of various equations (MDRD or CKD-EPI) and more recently by the measurement of plasmatic C-cystatin. Under physiological conditions, GFR is a stable parameter that is regulated by the intrinsic vascular and tubular autoregulation, by the balance between paracrine and endocrine agents acting as vasoconstrictors and vasodilators, and by the effects of renal sympathetic nerves. The mechanisms controlling GFR regulation are complex. This is due to the variety of vasoactive agents and their targets, and multiple interactions between them. Nevertheless, the relative stability of GFR during important variations of systemic haemodynamics and volaemia is due to three major operating mechanisms: autoregulation of the afferent arteriolar resistance, local synthesis and action of angiotensin II, and the sensitivity of renal resistance vessels to respond to NO release.
36
Tibaldi, Stefano, and Franco Molteni. Atmospheric Blocking in Observation and Models. Oxford University Press, 2018. http://dx.doi.org/10.1093/acrefore/9780190228620.013.611.
Abstract:
The atmospheric circulation in the mid-latitudes of both hemispheres is usually dominated by westerly winds and by planetary-scale and shorter-scale synoptic waves, moving mostly from west to east. A remarkable and frequent exception to this “usual” behavior is atmospheric blocking. Blocking occurs when the usual zonal flow is hindered by the establishment of a large-amplitude, quasi-stationary, high-pressure meridional circulation structure which “blocks” the flow of the westerlies and the progression of the atmospheric waves and disturbances embedded in them. Such blocking structures can have lifetimes varying from a few days to several weeks in the most extreme cases. Their presence can strongly affect the weather of large portions of the mid-latitudes, leading to the establishment of anomalous meteorological conditions. These can take the form of strong precipitation episodes or persistent anticyclonic regimes, leading in turn to floods, extreme cold spells, heat waves, or short-lived droughts. Even air quality can be strongly influenced by the establishment of atmospheric blocking, with episodes of high concentrations of low-level ozone in summer and of particulate matter and other air pollutants in winter, particularly in highly populated urban areas.Atmospheric blocking has the tendency to occur more often in winter and in certain longitudinal quadrants, notably the Euro-Atlantic and the Pacific sectors of the Northern Hemisphere. In the Southern Hemisphere, blocking episodes are generally less frequent, and the longitudinal localization is less pronounced than in the Northern Hemisphere.Blocking has aroused the interest of atmospheric scientists since the middle of the last century, with the pioneering observational works of Berggren, Bolin, Rossby, and Rex, and has become the subject of innumerable observational and theoretical studies. The purpose of such studies was originally to find a commonly accepted structural and phenomenological definition of atmospheric blocking. The investigations went on to study blocking climatology in terms of the geographical distribution of its frequency of occurrence and the associated seasonal and inter-annual variability. Well into the second half of the 20th century, a large number of theoretical dynamic works on blocking formation and maintenance started appearing in the literature. Such theoretical studies explored a wide range of possible dynamic mechanisms, including large-amplitude planetary-scale wave dynamics, including Rossby wave breaking, multiple equilibria circulation regimes, large-scale forcing of anticyclones by synoptic-scale eddies, finite-amplitude non-linear instability theory, and influence of sea surface temperature anomalies, to name but a few. However, to date no unique theoretical model of atmospheric blocking has been formulated that can account for all of its observational characteristics.When numerical, global short- and medium-range weather predictions started being produced operationally, and with the establishment, in the late 1970s and early 1980s, of the European Centre for Medium-Range Weather Forecasts, it quickly became of relevance to assess the capability of numerical models to predict blocking with the correct space-time characteristics (e.g., location, time of onset, life span, and decay). Early studies showed that models had difficulties in correctly representing blocking as well as in connection with their large systematic (mean) errors.Despite enormous improvements in the ability of numerical models to represent atmospheric dynamics, blocking remains a challenge for global weather prediction and climate simulation models. Such modeling deficiencies have negative consequences not only for our ability to represent the observed climate but also for the possibility of producing high-quality seasonal-to-decadal predictions. For such predictions, representing the correct space-time statistics of blocking occurrence is, especially for certain geographical areas, extremely important.