scholarly journals Characterization of Evolution Stages, Groundwater and Soil Features of the Mud Forest Landscape at Qian-an (China)

2020 ◽  
Vol 10 (21) ◽  
pp. 7427
Author(s):  
XiangJian Rui ◽  
Lei Nie ◽  
Yan Xu ◽  
Chao Du ◽  
FanSheng Kong ◽  
...  
Keyword(s):  
Geological Structure ◽  
Forest Landscape ◽  
High Porosity ◽  
Short Term ◽  
Soil Features ◽  
Geological Processes ◽  
Formation And Evolution ◽  
Landscape Formation

The research on geological landscape has received more and more attention worldwide. The National Geological Park of Qian-an mud forest, located in Qian-an Country, Songyuan City (Jilin Province, China) is a rare natural geological landscape formed by erosion. Mud forest landscape has undergone long-term geological processes, and it is still in continuous evolution due to subsurface erosion. In the process of the mud forest landscape formation and evolution, distinct stages have been recognized. The subsurface erosion factors of the mud forest area were identified by groundwater and soil samples characterization, and the mechanism of the formation of the mud forest is studied. Results show that the occurrence of subsurface erosion is controlled by four factors: (1) The head difference of terrace increases due to geological structure, (2) The dry and cold paleoclimate increases the accumulation of soluble salts. Concentrated precipitation in the short term also promotes subsurface erosion. (3) The high content of sodium ions in groundwater promotes the dispersion of soil, and (4) Loess-like soil is characterized by high porosity, low plasticity, and dispersibility.

scholarly journals (M,β)-Stability of Positive Linear Systems

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Octavian Pastravanu ◽  
Mihaela-Hanako Matcovschi
Keyword(s):  
Linear System ◽  
Linear Systems ◽  
Transient Behavior ◽  
Short Term ◽  
Time Dynamics ◽  
The Right ◽  
Long Term Behavior ◽  
Stability Concept

The main purpose of this work is to show that the Perron-Frobenius eigenstructure of a positive linear system is involved not only in the characterization of long-term behavior (for which well-known results are available) but also in the characterization of short-term or transient behavior. We address the analysis of the short-term behavior by the help of the “(M,β)-stability” concept introduced in literature for general classes of dynamics. Our paper exploits this concept relative to Hölder vectorp-norms,1≤p≤∞, adequately weighted by scaling operators, focusing on positive linear systems. Given an asymptotically stable positive linear system, for each1≤p≤∞, we prove the existence of a scaling operator (built from the right and left Perron-Frobenius eigenvectors, with concrete expressions depending onp) that ensures the best possible values for the parametersMandβ, corresponding to an “ideal” short-term (transient) behavior. We provide results that cover both discrete- and continuous-time dynamics. Our analysis also captures the differences between the cases where the system dynamics is defined by matrices irreducible and reducible, respectively. The theoretical developments are applied to the practical study of the short-term behavior for two positive linear systems already discussed in literature by other authors.

Long-term and Short-term Spectral Stability Characterization of Supercontinuum Laser Sources

2006 ◽  
Author(s):  
Roberto Llorente ◽  
Marta Beltran ◽  
Joaquin Perez ◽  
Noboru Uehara ◽  
Md. Khan ◽  
...  
Keyword(s):  
Spectral Stability ◽  
Short Term ◽  
Laser Sources ◽  
Supercontinuum Laser

Hindered phenolic antioxidants as heat-oxygen stabilizers for HDPE

2020 ◽  
pp. 096739112097116
Author(s):  
Yuru Wang ◽  
He Ren ◽  
Yibin Yan ◽  
Shuyan He ◽  
Shuang Wu ◽  
...  
Keyword(s):  
Pure Oxygen ◽  
Phenolic Antioxidants ◽  
Irganox 1010 ◽  
Short Term ◽  
Scanning Calorimetry ◽  
Oxidation Induction Time ◽  
Melt Flow Rate ◽  
Stability Tests

The effects of four hindered phenolic antioxidants in the short-term heat-oxygen stability of High-Density Polyethylene (HDPE) was evaluated by the Melt Flow Rate (MFR) and Oxidation Induction Time (OIT) analyses. The results showed that Irganox 1330 and Irganox 1010 had more excellent processing property and oxidation resistance behavior in HDPE than Irganox 1024 and Irganox 3114. The OIT values of HDPE with Irganox 1330 and Irganox 1010 were up to 97.25 min and 89.73 min respectively. The long-term accelerated heat-oxygen stability tests of HDPE containing hindered phenolic antioxidants were carried out at 110°C in deionized water pressurized with pure oxygen at a pressure of 10 MPa. The characterization of the long-term heat-oxygen stability was performed by Fourier Transform Infrared (FTIR), Differential Scanning Calorimetry (DSC) and tensile testing. However, the results exhibited that the aging resistance of HDPE containing Irganox 1010 was inferior to that of HDPE containing Irganox 1024 and Irganox 3114, which is quite contrary to their short-term effect on HDPE stabilization. It may be speculated that the ester groups of Irganox 1010 undergo hydrolysis during the long-term heat-oxygen stability tests, leading to the formation of 3-(3,5-ditert-butyl-4-hydroxy-phenyl) propanoic acid and pentaerythritol.

scholarly journals On the Identification and Characterization of Drought and Aridity in Postglacial Paleoenvironmental Records from the Northern Great Plains

2004 ◽  
Vol 56 (2-3) ◽  
pp. 229-246 ◽  
Author(s):  
Alwynne B. Beaudoin
Keyword(s):  
Global Warming ◽  
High Resolution ◽  
Great Plains ◽  
Northern Great Plains ◽  
Short Term ◽  
Instrumental Data ◽  
Proxy Records ◽  
Identification And Characterization

Abstract The Northern Great Plains region is especially sensitive to drought and is likely to be even more drought-prone under projected global warming. Drought has been invoked as an explanatory factor for changes seen in postglacial paleoenvironmental records. These proxy records may extend drought history derived from instrumental data. Moreover, in the last decade, some paleoenvironmental studies have been expressly undertaken for the examination of long-term drought history. Nevertheless, few such studies explicitly define drought. This makes it difficult to compare results or to understand what the results mean in terms of the operational drought definitions that are used in resource management. Operational drought is defined as usually short-term; longer sustained dry intervals reflect a shift to aridity. Therefore, high resolution paleoenvironmental proxies (annual or subdecadal) are best for the investigation of drought history. Such proxies include tree rings and some lake records. However, most lake-based records are sampled at lower resolution (decadal or subcentury) and are therefore providing aridity signals.

scholarly journals A review of wave climate and prediction along the Spanish Mediterranean coast

2008 ◽  
Vol 8 (6) ◽  
pp. 1217-1228 ◽  
Author(s):  
A. Sánchez-Arcilla ◽  
D. González-Marco ◽  
R. Bolaños
Keyword(s):  
Field Data ◽  
Wave Climate ◽  
Mediterranean Coast ◽  
Short Term ◽  
Wave Fields ◽  
Wave Parameters

Abstract. This paper reviews the characterization of wave storms along the Spanish/Catalan Mediterranean coast. It considers the "physical" and "statistical" description of wave parameters and how they are affected by the prevailing meteo patterns and the sharp gradients in orography and bathymetry. The available field data and numerically simulated wave fields are discussed from this perspective. The resulting limits in accuracy and predictability are illustrated with specific examples. This allows deriving some conclusions for both short-term operational predictions and a long-term climatic assessment.

scholarly journals Preconditioning and Acute Effects of Flavonoids in Protecting Cardiomyocytes from Oxidative Cell Death

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Masoumeh Akhlaghi ◽  
Brian Bandy
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Relative Effectiveness ◽  
Epigallocatechin Gallate ◽  
Short Term ◽  
Higher Doses

While flavonoids can reportedly protect against cardiac ischemia-reperfusion injury, the relative effectiveness of different flavonoids and the mechanisms involved are unclear. We compared protection by different flavonoids using rat embryonic ventricular H9c2 cells subjected to simulated ischemia-reperfusion (IR) and totert-butyl hydroperoxide (t-buOOH). Characterization of the IR model showed the relative contributions of glucose, serum, and oxygen deprivation to cell death. With long-term (2-3 day) pretreatment before IR the best protection was given by catechin, epigallocatechin gallate, proanthocyanidins, and ascorbate, which protected at all doses. Quercetin protected (34%) at 5 μM but was cytotoxic at higher doses. Cyanidin protected mildly (10–15%) at 5 and 20 μM, while delphinidin had no effect at 5 μM and was cytotoxic at higher doses. Comparing long-term and acute protection by catechin, a higher concentration was needed for benefit with acute (1 hr) pretreatment. With a pure oxidative stress (t-buOOH) only quercetin significantly protected with 3-day pretreatment, while with short-term (1 h) pretreatments protection was best with quercetin and epigallocatechin gallate. The results suggest catechins to be especially useful as IR preconditioning agents, while quercetin and epigallocatechin gallate may be the most protective acutely in situations of oxidative stress.

scholarly journals Characterization of stipe elongation of the mushroom Coprinopsis cinerea

Microbiology ◽  
2014 ◽  
Vol 160 (9) ◽  
pp. 1893-1902 ◽  
Author(s):  
Wenming Zhang ◽  
Xiuxiu Wu ◽  
Yajun Zhou ◽  
Zhonghua Liu ◽  
Wen Zhang ◽  
...  
Keyword(s):  
Model Material ◽  
Apical Region ◽  
Coprinopsis Cinerea ◽  
Short Term ◽  
Protein Inactivation ◽  
Stipe Elongation ◽  
Snail Protein ◽  
Two Phases

Previously, we observed an acid-induced short-term wall extension in Flammulina velutipes apical stipes during a 15 min period after a change from a neutral to an acidic pH. This acid-induced stipe wall extension was eliminated by heating and reconstituted by a snail expansin-like protein, although we failed to isolate any endogenous expansin-like protein from F. velutipes because of its limited 1 mm fast elongation region. In this study, we report that Coprinopsis cinerea stipes possess a 9 mm fast elongation apical region, which is suitable as a model material for wall extension studies. The elongating apical stipe showed two phases of acid-induced wall extension, an initial quick short-term wall extension during the first 15 min and a slower, gradually decaying long-term wall extension over the subsequent 2 h. After heating or protein inactivation pretreatment, apical stipes lost the long-term wall extension, retaining a slower short-term wall extension, which was reconstituted by an expansin-like snail protein. In contrast, the non-elongating basal stipes showed only a weaker short-term wall extension. We propose that the long-term wall extension is a protein-mediated process involved in stipe elongation, whereas the short-term wall extension is a non-protein mediated process not involved in stipe elongation.

scholarly journals “Typical” Migrant Biographies from Sfântu Gheorghe/Sepsiszentgyörgy

2020 ◽  
Vol 18 (2) ◽  
pp. 51-74
Author(s):  
Andrea Sólyom
Keyword(s):  
Local Context ◽  
Narrative Strategies ◽  
Short Term ◽  
Theoretical Approaches ◽  
Youth Migration ◽  
Push And Pull ◽  
The Town ◽  
Quantitative And Qualitative Methods

The analysis on youth migration was developed in the framework of “YOUMIG – Improving institutional capacities and fostering cooperation to tackle the impacts of transnational youth migration” project. The present paper offers a picture about the “typical” biographies of young migrants. In the municipality of Sfântu Gheorghe emigration is the most important migratory trend. Among emigrants one can identify short term migrants – this type is distinctive of Roma migrants, too; long term migrants, most of them aiming to earn a living through their labour migration; while a smaller group studies and works abroad at the same time. There are also return migrants but it is hard to estimate their proportions. During our research both quantitative and qualitative methods were used. The present paper is based on interviews conducted with young migrants. The present study starts with a short summary of the theoretical approaches applied during the analysis, followed by the methodology and a detailed characterization of the interviewees. The chapter presenting the local context concentrates on the demographic and economic indicators of the place of the fieldwork, then a short analysis is provided about the push and pull factors of the town based on the interviews. In order to achieve a detailed analysis three biographies were selected. Firstly, the milestones of their lives will be compared, followed by the analysis of their identitites and of their feelings toward the sending and emigrant (diaspora) communities. Secondly, their migration types and narrative strategies will be identified. Finally, the conclusions will highlight the similarities and differences revealed in the selected biographies. Keywords: migration, youth, biographies, narratives

scholarly journals Exposure Characterization of Haloacetic Acids in Humans for Exposure and Risk Assessment Applications: An Exploratory Study

2019 ◽  
Vol 16 (3) ◽  
pp. 471 ◽  
Author(s):  
Shahid Parvez ◽  
Jeffrey L. Ashby ◽  
Susana Y. Kimura ◽  
Susan D. Richardson
Keyword(s):  
Risk Assessment ◽  
Interindividual Variability ◽  
Individual Variability ◽  
Haloacetic Acids ◽  
Short Term ◽  
Cross Sectional ◽  
Exposure Biomarker ◽  
Short Term Exposure

Disinfected water is the major source of haloacetic acids (HAAs) in humans, but their inter- and intra-individual variability for exposure and risk assessment applications is under-researched. Thus, we measured HAAs in cross-sectional and longitudinal urine and water specimens from 17 individuals. Five regulated HAAs—mono, di, and trichloroacetic acid (MCAA, DCAA, and TCAA) and mono- and dibromoacetic acid (MBAA and DBAA)—and one unregulated HAA—bromochloroacetic acid (BCAA)—were measured. Urinary DCAA, MBAA, DBAA, and BCAA levels were always below the limits of detection (LOD). Measured levels and interindividual variability of urinary MCAA were higher than urinary TCAA. Longitudinal urinary specimens showed MCAA levels peaked in after-shower specimens, while TCAA levels remain unchanged. Correlation between urinary MCAA and TCAA was moderate but statistically significant. The prevalence of MCAA and TCAA in urine suggest they can be considered as biomarkers of HAA. Peak urinary MCAA in post-shower specimens suggest MCAA captures short-term exposure via dermal and/or inhalation, while urinary TCAA captures long-term exposure via ingestion. However, further research is warranted in a large pool of participants to test the reliability of MCAA as exposure biomarker.

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