scholarly journals Catchment classification: empirical analysis of hydrologic similarity based on catchment function in the eastern USA

2011 ◽  
Vol 8 (3) ◽  
pp. 4495-4534 ◽  
Author(s):  
K. Sawicz ◽  
T. Wagener ◽  
M. Sivapalan ◽  
P. A. Troch ◽  
G. Carrillo
Keyword(s):  
Environmental Gradients ◽  
Spatial Proximity ◽  
First Order ◽  
Response Characteristics ◽  
Control Climate ◽  
Eastern Usa ◽  
Catchment Function ◽  
Strong Control ◽  
Insight Into ◽  
Landscape Attributes

Abstract. Hydrologic similarity between catchments, derived from their similarity in how they respond to precipitation input, is the basis for classification, for transferability, for generalization and also for understanding the potential impacts of environmental change. An important question in this context is, in how far can widely available hydrologic information (precipitation-temperature-streamflow) be used to create a first order grouping of hydrologically similar catchments? We utilize a heterogeneous dataset of 280 catchments located in the Eastern US to understand hydrologic similarity in a 6-dimensional signature space across a region with strong environmental gradients. Signatures are defined as hydrologic response characteristics that provide some insight into the hydrologic function of catchments. A Bayesian clustering scheme is used to separate the catchments into 9 classes, which are subsequently analyzed with respect to their hydrologic, as well as climatic and landscape attributes. Based on the empirical results we hypothesize the following: (1) Streamflow elasticity with respect to precipitation is modified by the soil characteristics of a catchment. (2) Spatial proximity is a good first indicator of hydrologic similarity because of the strong control climate exerts on catchment function, and because it varies slowly in space.

scholarly journals Catchment classification: empirical analysis of hydrologic similarity based on catchment function in the eastern USA

2011 ◽  
Vol 15 (9) ◽  
pp. 2895-2911 ◽  
Author(s):  
K. Sawicz ◽  
T. Wagener ◽  
M. Sivapalan ◽  
P. A. Troch ◽  
G. Carrillo
Keyword(s):  
Environmental Gradients ◽  
Bayesian Clustering ◽  
Hydrologic Response ◽  
First Order ◽  
Response Characteristics ◽  
Eastern Usa ◽  
Streamflow Data ◽  
Catchment Function ◽  
Insight Into ◽  
Landscape Attributes

Abstract. Hydrologic similarity between catchments, derived from similarity in how catchments respond to precipitation input, is the basis for catchment classification, for transferability of information, for generalization of our hydrologic understanding and also for understanding the potential impacts of environmental change. An important question in this context is, how far can widely available hydrologic information (precipitation-temperature-streamflow data and generally available physical descriptors) be used to create a first order grouping of hydrologically similar catchments? We utilize a heterogeneous dataset of 280 catchments located in the Eastern US to understand hydrologic similarity in a 6-dimensional signature space across a region with strong environmental gradients. Signatures are defined as hydrologic response characteristics that provide insight into the hydrologic function of catchments. A Bayesian clustering scheme is used to separate the catchments into 9 homogeneous classes, which enable us to interpret hydrologic similarity with respect to similarity in climatic and landscape attributes across this region. We finally derive several hypotheses regarding controls on individual signatures from the analysis performed here.

Stochasting modeling of planetary ring systems

1984 ◽  
Vol 75 ◽  
pp. 461-469 ◽  
Author(s):  
Robert W. Hart
Keyword(s):  
Maximum Entropy ◽  
Ring System ◽  
The Sun ◽  
Ultimate State ◽  
Interparticle Interactions ◽  
Ring Systems ◽  
First Order ◽  
Planetary Ring ◽  
Insight Into

ABSTRACTThis paper models maximum entropy configurations of idealized gravitational ring systems. Such configurations are of interest because systems generally evolve toward an ultimate state of maximum randomness. For simplicity, attention is confined to ultimate states for which interparticle interactions are no longer of first order importance. The planets, in their orbits about the sun, are one example of such a ring system. The extent to which the present approximation yields insight into ring systems such as Saturn's is explored briefly.

Relational Chase Procedures Interpreted as Resolution with Paramodulation1

1991 ◽  
Vol 15 (2) ◽  
pp. 123-138
Author(s):  
Joachim Biskup ◽  
Bernhard Convent
Keyword(s):  
Alternative Interpretation ◽  
Order Logic ◽  
First Order Logic ◽  
Inference Problem ◽  
First Order ◽  
Inference Problems ◽  
The One ◽  
The Relationship ◽  
Theoretical Foundations ◽  
Insight Into

In this paper the relationship between dependency theory and first-order logic is explored in order to show how relational chase procedures (i.e., algorithms to decide inference problems for dependencies) can be interpreted as clever implementations of well known refutation procedures of first-order logic with resolution and paramodulation. On the one hand this alternative interpretation provides a deeper insight into the theoretical foundations of chase procedures, whereas on the other hand it makes available an already well established theory with a great amount of known results and techniques to be used for further investigations of the inference problem for dependencies. Our presentation is a detailed and careful elaboration of an idea formerly outlined by Grant and Jacobs which up to now seems to be disregarded by the database community although it definitely deserves more attention.

The contribution of publications of the Yorkshire Geological Society to the understanding of the geological development of the Carboniferous Pennine Basin, northern England

2020 ◽  
Vol 63 (1) ◽  
pp. 1-32
Author(s):  
C. N. Waters ◽  
D. W. Holliday ◽  
J. I. Chisholm
Keyword(s):  
Industrial Revolution ◽  
Mineral Resources ◽  
Deep Time ◽  
The Bible ◽  
Great Insight ◽  
History Of ◽  
Sea Level Variations ◽  
Strong Control ◽  
Insight Into ◽  
Peak District

The Carboniferous rocks of the Pennine Basin form the topographical spine of the region between the Scottish Border and the Peak District. They provided many of the mineral resources that fuelled the Industrial Revolution and the growth of the great northern English cities. The description of these resources was very much a focus of early papers in the Proceedings, but they went beyond the assessment of their economic importance, providing striking early insights into our understanding of deep time when the Bible still had a strong control on scientific thinking. Over a 180 year history of publication, the Proceedings and Occasional Publications contain an unparalleled description of the rocks of the Pennine Basin of Carboniferous deposition, and they continue to provide great insight into what have been intensively studied successions but of which much still remains to be learned. This review considers the relevance of these publications to our understanding of the sedimentology of Carboniferous strata, the geometries of Carboniferous basins, how these basins constrained the formation of reefs and controlled the movement of rivers and deltas in the process of eventual infill of these basins, and how sea-level variations influenced the development of cyclical successions, the hallmark of much of the Carboniferous succession.

First-order-reversal-curve analysis of rare earth permanent magnet nanostructures: insight into the coercivity enhancement mechanism through regulating the Nd-rich phase

2021 ◽  
Author(s):  
Junjie Xu ◽  
Kai Zhu ◽  
Wei Li ◽  
Xiaobai Wang ◽  
Ziyu Yang ◽  
...  
Keyword(s):  
Rare Earth ◽  
Permanent Magnet ◽  
Curve Analysis ◽  
Magnetic Interactions ◽  
Phase Content ◽  
Rich Phase ◽  
Enhancement Mechanism ◽  
First Order ◽  
Insight Into

The coercivity enhancement mechanism of Nd2Fe14B-based nanostructures with Nd-rich phase is revealed by first-order-reversal-curve diagram, which is that increased Nd-rich phase content leads to optimized magnetic interactions and microstructure.

Step Response Characteristics of Anisotropic Gel Actuator Hybridized with Nanosheet Liquid Crystal

2019 ◽  
Vol 31 (5) ◽  
pp. 647-656 ◽  
Author(s):  
Hitoshi Kino ◽  
◽  
Akihiro Kiyota ◽  
Takumi Inadomi ◽  
Tomonori Kato ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Steady State ◽  
Time Constant ◽  
Step Response ◽  
Response Property ◽  
First Order ◽  
Response Characteristics ◽  
Thermal Change ◽  
Heating And Cooling ◽  
Original Size

In this study, we focus on a soft anisotropic gel actuator hybridized with nanosheet liquid crystal. This gel actuator is highly hydrophilic and can be operated underwater. Gel actuators can contract when heated and expand back to their original size when cooled down. It is anisotropic in the contraction direction, aligned with the orientation of the nanosheet liquid crystal. However, details of this step response property against the actuator undergoing thermal change have not been clarified. In this paper, we introduce a method to measure the step response using a square test sheet with a side length of 2–10 mm and thickness of 0.1–1.0 mm. This measurement was used to measure the heating and cooling step response. The obtained result was approximated using a first-order lag system to determine a steady-state value and time constant. In addition, the characteristics of steady-state value and time constant were clarified from the viewpoint of shapes such as specific surface area and thickness.

scholarly journals From Ischemic Conditioning to ‘Hyperconditioning’: Clinical Phenomenon and Basic Science Opportunity

Dose-Response ◽  
2014 ◽  
Vol 12 (4) ◽  
pp. dose-response.1 ◽  
Author(s):  
Peter Whittaker ◽  
Karin Przyklenk
Keyword(s):  
Basic Science ◽  
Ischemia Reperfusion ◽  
Clinical Importance ◽  
Structural Elements ◽  
Ischemic Conditioning ◽  
Response Characteristics ◽  
Infarct Size Reduction ◽  
Clinical Consequences ◽  
Clinical Phenomenon ◽  
Insight Into

Thousands of articles have been published on the topic of ischemic conditioning. Nevertheless, relatively little attention has been given to assessment of conditioning's dose-response characteristics. Specifically, the consequences of multiple conditioning episodes, what we will term “hyperconditioning”, have seldom been examined. We propose that hyperconditioning warrants investigation because it; (1) may be of clinical importance, (2) could provide insight into conditioning mechanisms, and (3) might result in development of novel models of human disease. The prevalence of angina pectoris and intermittent claudication is sufficiently high and the potential for daily ischemia-reperfusion episodes sufficiently large that hyperconditioning is a clinically relevant phenomenon. In basic science, attenuation of conditioning-mediated infarct size reduction found in some studies after hyperconditioning offers a possible means to facilitate further discernment of cardioprotective signaling pathways. Moreover, hyperconditioning's impact extends beyond cytoprotection to tissue structural elements. Several studies demonstrate that hyperconditioning produces collagen injury (primarily fiber breakage). Such structural impairment could have adverse clinical consequences; however, in laboratory studies, selective collagen damage could provide the basis for models of cardiac rupture and dilated cardiomyopathy. Accordingly, we propose that hyperconditioning represents the dark, but potentially illuminating, side of ischemic conditioning - a paradigm that merits attention and prospective evaluation.

Non-strong mixing autoregressive processes

1984 ◽  
Vol 21 (4) ◽  
pp. 930-934 ◽  
Author(s):  
Donald W. K. Andrews
Keyword(s):  
Direct Proof ◽  
Strong Mixing ◽  
Autoregressive Processes ◽  
Mixing Conditions ◽  
First Order ◽  
Insight Into

Certain first-order autoregressive processes are shown not to be strong mixing. A direct proof is given. This proof gives considerably more insight into the nature of the result than do proofs by contradiction. The result and proof help to clarify the relation between the autoregressive and strong mixing conditions.

scholarly journals Onset of autumn senescence in High Arctic plants shows similar patterns in natural and experimental snow depth gradients

2021 ◽  
Author(s):  
Friederike Gehrmann ◽  
Camille Ziegler ◽  
Elisabeth J. Cooper
Keyword(s):  
Environmental Gradients ◽  
Growing Season ◽  
High Arctic ◽  
Plant Responses ◽  
Bud Burst ◽  
Delayed Senescence ◽  
Arctic Plants ◽  
Autumn Senescence ◽  
Depth Gradients ◽  
Insight Into

Predicted changes in snow cover and temperature raise uncertainties about how the beginning and the end of the growing season will shift for Arctic plants. Snowmelt timing and temperature are known to affect the timing of bud burst, but their effects on autumn senescence are less clear. To address this, researchers have examined senescence under natural and experimental environmental gradients. However, these approaches address different aspects of plant responses and the extent to which they can be compared is poorly understood. In this study, we show that the effect of snowmelt timing on the timing of autumn senescence in High Arctic plants is the same between a natural and an experimental gradient in three out of four studied species. While the two approaches mostly produce comparable results, they give in combination greater insight into the phenological responses to predicted climate changes. We also showed that a short warming treatment in autumn delayed senescence by 3.5 days in D. octopetala, which is a 10 % extension of the growing season end for this species. Warming treatments have commonly been applied to the whole growing season, but here we show that even isolated autumn warming can be sufficient to affect plant senescence.

Cyclostationary Approach for Instabilities Detection and Condition Monitoring of Centrifugal Compressor

2020 ◽  
Author(s):  
Mateusz Stajuda ◽  
David Garcia Cava ◽  
Grzegorz Liśkiewicz
Keyword(s):  
Condition Monitoring ◽  
Centrifugal Compressor ◽  
Operating Conditions ◽  
Periodic Signal ◽  
Centrifugal Compressors ◽  
First Order ◽  
Standard Signal ◽  
Processing Techniques ◽  
Signal Processing Techniques ◽  
Insight Into

Abstract This study intends to explore the capabilities of the cyclostationary approach for instabilities detection and operating conditions monitoring of centrifugal compressors. Cyclostationary approach offers powerful signal analysis methods, applicable to different processes. It was proven useful for analysis of vibration, acoustic and pressure data for systems exhibiting periodicity. Cyclostationarity has been used for extracting subtle changes between cycles of the periodic signal which could be used for condition monitoring. Recent research focuses on employing this method for fault indication. Cyclostationary approach has not been extensively used in the field of turbomachinery, except for a few cases when it was proven to give a better insight into flow structure than standard signal processing techniques and allow for the detection of instabilities in flow systems. Thus, the cyclostationary approach may be suitable for instabilities detection and condition monitoring in centrifugal compressors. This paper exploits various techniques employing a cyclostationary framework for instabilities detection and operating conditions monitoring with the use of pressure signals from the low-speed centrifugal compressor. The most prospective cyclostationarity-based indicators are applied for the detection of instabilities. Due to a lack of second-order cyclostationarity, the study confines to the analysis of first-order cyclostationarity strongly exhibited in the compressor pressure signal. First-order cyclostationarity analysis provides an indication of instabilities and working conditions differentiation, but due to time-domain sampling, it is not fully robust and reliable. The highest potential is perceived in the cyclostationary approach use to extract changes between cycles. Different measures of change in variability could serve as a valuable indicator of instabilities.

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