Allometric relationships and dendroecology of the dwarf shrub Dryas integrifolia near Churchill, subarctic Manitoba

2007 ◽  
Vol 85 (6) ◽  
pp. 585-597 ◽  
Author(s):  
R. Au ◽  
J.C. Tardif
Keyword(s):  
Cross Sections ◽  
Growth Rates ◽  
Allometric Relationships ◽  
Growth Rings ◽  
Important Species ◽  
Future Studies ◽  
Disturbed Areas ◽  
Northern Areas ◽  
Cross Dating ◽  
The Impact

Shrubs have generally been overlooked in dendrochronology, and little information exists on allometric relationships in dwarf shrubs. Dryas integrifolia M. Vahl. has been recognized as an important species in revegetation of disturbed gravel pits in northern areas. In this study, the dimensions (mat, stem, and root) of D. integrifolia shrubs were measured in four populations having recolonized disturbed areas, and anatomical slides containing growth rings were prepared for each individual. The first objective was to compare allometric relationships among descriptors of shrub dimension and between these descriptors and shrub age. Secondary objectives included documenting maximum age and evaluation of the potential for cross-dating among shrubs. Strong, consistent allometric relationships between aboveground dimensions were observed among individuals from all sites, although growth rates varied within and between sites. This indicated that even though aboveground shrub dimensions grow proportionally to one another, these measurements cannot be used to infer age, because of differences in growth rates among D. integrifolia shrubs. However, numerous cross-sections from D. integrifolia shrubs could be successfully cross-dated, and a short chronology was developed. The radial growth – climate association was found to be similar to that of dominant tree species of the region regarding the impact of October conditions. Increased snowfall in October prior to and warm May temperature during the year of ring formation appear to restrict growth of these shrubs by altering the onset of the growing season. This study has demonstrated that it is possible to accurately date D. integrifolia shrubs, and this ability may be applied to future studies involving population dynamics and remediation of open gravel sites. Growth rings also have the potential to be used in other Arctic shrubs.

The efficiency of application of virtual cross-sections method and hypotheses MELS in problems of wave signal propagation in elastic waveguides with rough surfaces

2016 ◽  
pp. 3564-3575 ◽  
Author(s):  
Ara Sergey Avetisyan
Keyword(s):  
Half Space ◽  
Cross Sections ◽  
Classical Method ◽  
Signal Propagation ◽  
Elastic Half Space ◽  
Layered Systems ◽  
Surface Layers ◽  
Inhomogeneous Surface ◽  
Wave Signal ◽  
The Impact

The efficiency of virtual cross sections method and MELS (Magneto Elastic Layered Systems) hypotheses application is shown on model problem about distribution of wave field in thin surface layers of waveguide when plane wave signal is propagating in it. The impact of surface non-smoothness on characteristics of propagation of high-frequency horizontally polarized wave signal in isotropic elastic half-space is studied. It is shown that the non-smoothness leads to strong distortion of the wave signal over the waveguide thickness and along wave signal propagation direction as well.  Numerical comparative analysis of change in amplitude and phase characteristics of obtained wave fields against roughness of weakly inhomogeneous surface of homogeneous elastic half-space surface is done by classical method and by proposed approach for different kind of non-smoothness.

scholarly journals A note on the relations between elastic and inelastic interactions and increasing ratio σel(s)/σtot(s) at the LHC

2019 ◽  
Vol 34 (32) ◽  
pp. 1950259 ◽  
Author(s):  
S. M. Troshin ◽  
N. E. Tyurin
Keyword(s):  
Elastic Scattering ◽  
Energy Dependence ◽  
Impact Parameter ◽  
Cross Sections ◽  
Parameter Dependence ◽  
Slope Parameter ◽  
Short Notice ◽  
Inelastic Interactions ◽  
The Impact ◽  
Mode A

We comment briefly on relations between the elastic and inelastic cross-sections valid for the shadow and reflective modes of the elastic scattering. Those are based on the unitarity arguments. It is shown that the redistribution of the probabilities of the elastic and inelastic interactions (the form of the inelastic overlap function becomes peripheral) under the reflective scattering mode can lead to increasing ratio of [Formula: see text] at the LHC energies. In the shadow scattering mode, the mechanism of this increase is a different one, since the impact parameter dependence of the inelastic interactions probability is central in this mode. A short notice is also given on the slope parameter and the leading contributions to its energy dependence in both modes.

scholarly journals Charged current Drell-Yan production at N3LO

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Claude Duhr ◽  
Falko Dulat ◽  
Bernhard Mistlberger
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Production Cross Section ◽  
Production Cross ◽  
Hadron Collider ◽  
Charge Asymmetry ◽  
Charged Current ◽  
Leading Order ◽  
Neutrino Pair ◽  
The Impact

Abstract We present the production cross section for a lepton-neutrino pair at the Large Hadron Collider computed at next-to-next-to-next-to-leading order (N3LO) in QCD perturbation theory. We compute the partonic coefficient functions of a virtual W± boson at this order. We then use these analytic functions to study the progression of the perturbative series in different observables. In particular, we investigate the impact of the newly obtained corrections on the inclusive production cross section of W± bosons, as well as on the ratios of the production cross sections for W+, W− and/or a virtual photon. Finally, we present N3LO predictions for the charge asymmetry at the LHC.

scholarly journals A Fundamental Study on the Development of New Energy Performance Index in Office Buildings

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2064
Author(s):  
Jin-Hee Kim ◽  
Seong-Koo Son ◽  
Gyeong-Seok Choi ◽  
Young-Tag Kim ◽  
Sung-Bum Kim ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Requirement ◽  
Energy Performance ◽  
Office Buildings ◽  
Light Transmittance ◽  
Wall Structure ◽  
Fundamental Study ◽  
Future Studies ◽  
U Value ◽  
The Impact

Recently, there have been significant concerns regarding excessive energy use in office buildings with a large window-to-wall ratio (WWR) because of the curtain wall structure. However, prior research has confirmed that the impact of the window area on energy consumption varies depending on building size. A newly proposed window-to-floor ratio (WFR) correlates better with energy consumption in the building. In this paper, we derived the correlation by analyzing a simulation using EnergyPlus, and the results are as follows. In the case of small buildings, the results of this study showed that the WWR and energy requirement increase proportionally, and the smaller the size is, the higher the energy sensitivity will be. However, results also confirmed that this correlation was not established for buildings approximately 3600 m2 or larger. Nevertheless, from analyzing the correlation between the WFR and the energy requirements, it could be deduced that energy required increased proportionally when the WFR was 0.1 or higher. On the other hand, the correlation between WWR, U-value, solar heat gain coefficient (SHGC), and material property values of windows had little effect on energy when the WWR was 20%, and the highest effect was seen at a WWR of 100%. Further, with an SHGC below 0.3, the energy requirement decreased with an increasing WWR, regardless of U-value. In addition, we confirmed the need for in-depth research on the impact of the windows’ U-value, SHGC, and WWR, and this will be verified through future studies. In future studies on window performance, U-value, SHGC, visible light transmittance (VLT), wall U-value as sensitivity variables, and correlation between WFR and building size will be examined.

scholarly journals Laurel Wilt: Current and Potential Impacts and Possibilities for Prevention and Management

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 181
Author(s):  
Rabiu O. Olatinwo ◽  
Stephen W. Fraedrich ◽  
Albert E. Mayfield
Keyword(s):  
United States ◽  
Tree Mortality ◽  
The United States ◽  
Persea Americana ◽  
Laurel Wilt ◽  
Important Species ◽  
Invasive Insects ◽  
Raffaelea Lauricola ◽  
Redbay Ambrosia Beetle ◽  
The Impact

In recent years, outbreaks of nonnative invasive insects and pathogens have caused significant levels of tree mortality and disturbance in various forest ecosystems throughout the United States. Laurel wilt, caused by the pathogen Raffaelea lauricola (T.C. Harr., Fraedrich and Aghayeva) and the primary vector, the redbay ambrosia beetle (Xyleborus glabratus Eichhoff), is a nonnative pest-disease complex first reported in the southeastern United States in 2002. Since then, it has spread across eleven southeastern states to date, killing hundreds of millions of trees in the plant family Lauraceae. Here, we examine the impacts of laurel wilt on selected vulnerable Lauraceae in the United States and discuss management methods for limiting geographic expansion and reducing impact. Although about 13 species belonging to the Lauraceae are indigenous to the United States, the highly susceptible members of the family to laurel wilt are the large tree species including redbay (Persea borbonia (L.) Spreng) and sassafras (Sassafras albidum (Nutt.) Nees), with a significant economic impact on the commercial production of avocado (Persea americana Mill.), an important species native to Central America grown in the United States. Preventing new introductions and mitigating the impact of previously introduced nonnative species are critically important to decelerate losses of forest habitat, genetic diversity, and overall ecosystem value.

Reflections on the biochemistry ofEchinococcus: past, present and future

Parasitology ◽  
2009 ◽  
Vol 136 (12) ◽  
pp. 1643-1652 ◽  
Author(s):  
D. P. McMANUS
Keyword(s):  
Hydatid Disease ◽  
Biochemical Analysis ◽  
Species Variation ◽  
Research Directions ◽  
Future Studies ◽  
Tegumental Surface ◽  
Research Areas ◽  
General Metabolism ◽  
New Research ◽  
The Impact

SUMMARYThis review discusses 5 of my earliest papers on the biochemistry of larvalEchinococcuspublished inParasitologyin the 1970s and 1980s. Two of the publications consider aspects of the basic biochemistry, intermediary metabolism and the regulation of respiratory pathways inE. granulosusandE. multilocularis, and emphasize the existence of inter- and intra-species variation in their general metabolism. The third reports on the detailed biochemical analysis of the tegumental surface of the protoscolex ofE. granulosus, and the final 2 papers describe the genomic cloning ofEchinococcusDNA fragments and their use, along with other DNA markers, in molecular identification ofE. granulosusisolates collected worldwide from areas endemic for hydatid disease. A number of years have elapsed since these publications inParasitologyand, in this Centenary Issue article, I reflect briefly on some of the subsequent studies undertaken in these research areas that have advanced the field. As well, I provide brief insight on new research directions, emphasizing the impact of molecular biology and associated techniques on future studies ofEchinococcusand hydatid disease.

scholarly journals Changing trends and emissions of hydrochlorofluorocarbons and their hydrofluorocarbon replacements

2016 ◽  
Author(s):  
Peter G. Simmonds ◽  
Matthew Rigby ◽  
Archibold McCulloch ◽  
Simon O'Doherty ◽  
Dickon Young ◽  
...  
Keyword(s):  
Growth Rates ◽  
Montreal Protocol ◽  
Hfc 134A ◽  
Production And Consumption ◽  
Ozone Depleting Substances ◽  
Phase Out ◽  
Article 5 ◽  
The Impact ◽  
Global Emissions

Abstract. High frequency, in situ global observations of HCFC-22 (CHClF2), HCFC-141b (CH3CCl2F), HCFC-142b (CH3CClF2) and HCFC-124 (CHClFCF3) and their main HFC replacements HFC-134a (CH2FCF3), HFC-125 (CHF2CF3), HFC-143a (CH3CF3), and HFC-32 (CH2F2) have been used to determine their changing global growth rates and emissions in response to the Montreal Protocol and its recent amendments. The 2007 adjustment to the Montreal Protocol required the accelerated phase-out of HCFCs with global production and consumption capped in 2013, to mitigate their environmental impact as both ozone depleting substances and important greenhouse gases. We find that this change has coincided with a reduction in global emissions of the four HCFCs with aggregated global emissions in 2015 of 444 ± 75 Gg/yr, in CO2 equivalent units (CO2 e) 0.75 ± 0.1 Gt/yr, compared with 483 ± 70 Gg/yr (0.82 ± 0.1 Gt/yr CO2 e) in 2010. (All quoted uncertainties in this paper are 1 sigma). About 80 % of the total HCFC atmospheric burden in 2015 is HCFC-22, where global HCFC emissions appear to have been relatively constant in spite of the 2013 cap on global production and consumption. We attribute this to a probable increase in production and consumption of HCFC-22 in Montreal Protocol Article 5 (developing) countries and the continuing release of HCFC-22 from the large banks which dominate HCFC global emissions. Conversely, the four HFCs all show increasing annual growth rates with aggregated global HFCs emissions in 2015 of 329 ± 70 Gg/yr (0.65 ± 0.12 Gt/yr CO2 e) compared to 2010 with 240 ± 50 Gg/yr (0.47 ± 0.08 Gt/yr CO2 e). As HCFCs are replaced by HFCs we investigate the impact of the shift to refrigerant blends which have lower global warming potentials (GWPs). We also note that emissions of HFC-125 and HFC-32 appear to have increased more rapidly during the 2011–2015 5-yr period compared to 2006–2010.

scholarly journals #GERIATRICS: AN ANALYSIS OF THE IMPACT OF THE GERIATRICS TWITTER NETWORK

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S337-S337
Author(s):  
Varun Ayyaswami ◽  
Arpan Prabhu ◽  
Steven Gambert
Keyword(s):  
Network Analysis ◽  
Geriatric Medicine ◽  
The United States ◽  
Annual Growth ◽  
Social Media Analytics ◽  
User Characteristics ◽  
Future Studies ◽  
Digital Community ◽  
Support Organizations ◽  
The Impact

Abstract Twitter connects an international community of healthcare stakeholders, potentially augmenting access to information related to geriatric medicine. The purpose of this study is to analyze the geriatric medicine Twitter network, and we hypothesize this community has substantially grown in the last six years. We analyzed all publicly available tweets including the hashtag #geriatrics from January 1, 2013-January 1, 2019 using Symplur Signals, a health care social media analytics platform. We evaluated #geriatrics metrics over time related to activity, content analysis, user characteristics, engagement, and network analysis. A total of 159,008 tweets (containing 42.8% re-tweets) with the hashtag #geriatrics were written by 29,443 users, resulting in 393.6 million impressions. The number of tweets increased from 9,705 in 2013 to 39,151 in 2018 (32.2% compound annual growth); users increased from 3,366 in 2013 to 29,443 in 2018 (55.3% compound annual growth). Users were primarily found in the United States, United Kingdom, and Canada. The most commonly trending topic from 2013-2015 and from 2016-2018 was ‘older adults’. The top hashtags included in tweets with #geriatrics were #job, #aging, and #hpm (hospice and palliative medicine). Network analysis showed central hubs to be medical journals, provider organizations, individual physicians, and individual advocates. The top 150 influencers consisted primarily of physicians (49.1%), advocate/support organizations (13.8%), and media organizations (6.3%). The use of Twitter to promote geriatric medicine using #geriatrics has matured into an international digital community of interest. Future studies should examine hashtags related to age prevalent illnesses and hashtags likely to be used by patients.

scholarly journals The Impact of the Minimum Wage on Male and Female Employment and Earnings in India

2017 ◽  
Vol 34 (1) ◽  
pp. 28-64 ◽  
Author(s):  
Nidhiya Menon ◽  
Yana van der Meulen Rodgers
Keyword(s):  
Minimum Wage ◽  
Cross Sections ◽  
Urban Areas ◽  
Wage Gap ◽  
National Sample ◽  
Female Employment ◽  
Sample Survey ◽  
Market Outcomes ◽  
Wage Rates ◽  
The Impact

This study examines how employment and wages for men and women respond to changes in the minimum wage in India, a country known for its extensive system of minimum wage regulations across states and industries. Using repeated cross sections of India's National Sample Survey Organization employment survey data for the period 1983–2008 merged with a newly created database of minimum wage rates, we find that, regardless of gender, minimum wages in urban areas have little to no impact on labor market outcomes. However, minimum wage rates increase earnings in the rural sector, especially for men, without any employment losses. Minimum wage rates also increase the residual gender wage gap, which may be explained by weaker compliance among firms that hire female workers.

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