scholarly journals The pace of plant community change is accelerating in remnant prairies

2016 ◽  
Vol 2 (2) ◽  
pp. e1500975 ◽  
Author(s):  
Amy O. Alstad ◽  
Ellen I. Damschen ◽  
Thomas J. Givnish ◽  
John A. Harrington ◽  
Mark K. Leach ◽  
...  
Keyword(s):  
Fire History ◽  
Community Change ◽  
Ecological Change ◽  
Single Pair ◽  
Biodiversity Change ◽  
Long Term Trends ◽  
Using Data ◽  
The Impact ◽  
Historical Samples

Patterns of biodiversity are changing rapidly. “Legacy studies” use historical data to document changes between past and present communities, revealing long-term trends that can often be linked to particular drivers of ecological change. However, a single pair of historical samples cannot ascertain whether rates of change are consistent or whether the impact and identity of drivers have shifted. Using data from a second resurvey of 47 Wisconsin prairie remnants, we show that the pace of community change has increased with shifts in the strength of particular drivers. Annual rates of local colonization and extinction accelerated by 129 and 214%, respectively, between 1950 and 1987 and between 1987 and 2012. Two anthropogenic drivers—patch area and fire history—increased in importance between these periods. As the strength and number of anthropogenic forces increase, rates of biodiversity change are likely to accelerate in other ecosystems as well.

The impact of non-ideality on reconstructing spatial and temporal variations of aerosol acidity with multiphase buffer theory

2021 ◽  
Author(s):  
Yafang Cheng ◽  
Guangjie Zheng ◽  
Hang Su ◽  
Siwen Wang ◽  
Andrea Pozzer
Keyword(s):  
Molar Fraction ◽  
Temporal Variations ◽  
Spatial Variations ◽  
Acid Dissociation ◽  
Acid Dissociation Constant ◽  
Aerosol Acidity ◽  
Long Term Trends ◽  
Factor C ◽  
The Impact

<p>Aerosol acidity is a key parameter in atmospheric aqueous chemistry and strongly influence the interactions of air pollutants and ecosystem. The recently proposed multiphase buffer theory provides a framework to reconstruct long-term trends and spatial variations of aerosol pH based on the effective acid dissociation constant of ammonia (K<sub>a,NH3</sub><sup>*</sup>). However, non-ideality in aerosol droplets is a major challenge limiting its broad applications. Here, we introduced a non-ideality correction factor (c<sub>ni</sub>) and investigated its governing factors. We found that besides relative humidity (RH) and temperature, c<sub>ni</sub> is mainly determined by the molar fraction of NO<sub>3</sub><sup>-</sup> in aqueous-phase anions, due to different NH<sub>4</sub><sup>+</sup> activity coefficients between (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub>- and NH<sub>4</sub>NO<sub>3</sub>-dominated aerosols. A parameterization method is thus proposed to estimate c<sub>ni</sub> at given RH, temperature and NO<sub>3</sub><sup>-</sup> fraction, and is validated against long-term observations and global simulations. In the ammonia-buffered regime, with c<sub>ni</sub> correction the buffer theory can well reproduce the K<sub>a,NH3</sub><sup>*</sup> predicted by comprehensive thermodynamic models, with root-mean-square deviation ~0.1 and correlation coefficient ~1. Note that, while c<sub>ni</sub> is needed to predict K<sub>a,NH3</sub><sup>*</sup> levels, it is usually not the dominant contributor to its variations, as ~90% of the temporal or spatial variations in K<sub>a,NH3</sub><sup>*</sup> is due to variations in aerosol water and temperature.</p>

Evaluating the impact of ballast undercutting on the roughness of track geometry over different subgrade conditions

2017 ◽  
Vol 232 (5) ◽  
pp. 1266-1276
Author(s):  
Kirk M Scanlan ◽  
Michael T Hendry ◽  
C Derek Martin
Keyword(s):  
Surface Roughness ◽  
Organic Soils ◽  
Western Canada ◽  
Railway Ballast ◽  
Track Geometry ◽  
Track Maintenance ◽  
Heavy Haul ◽  
Long Term Trends ◽  
The Impact

The progressive degradation of railway ballast is often cited as a primary factor that contributes to the development of track roughness, while ballast renewal (undercutting) attempts to manage its long-term development. Soft subgrades have been shown to strongly influence track geometry and are a contributing factor that has not been considered during conventional track maintenance. This study evaluated the impact of undercutting on long-term trends in track geometry roughness, and what impact softer subgrades had on the effectiveness of undercutting. A combined 6.90 km of Class II–IV heavy-haul track in Western Canada (undercut in 2010 and 2011) formed the basis for this analysis. Annual traffic on these sections typically totals 50 million gross tonnes. Long-term trends in the track crosslevel, alignment, and surface roughness after ballast renewal were derived from 50 track geometry surveys carried out over a five-year period (2010–2015). The results showed that undercutting significantly reduced track roughness over sand, silt, clay, or till subgrades; however, it was often ineffective when used over soft organic subgrades. Thus, while ballast degradation is the primary cause of track roughness in segments constructed on mineral subgrades, it is not a mechanism that results in track geometry roughness over soft organic soils.

scholarly journals The Impact of Improved Thermistor Calibration on the Expendable Bathythermograph Profile Data

2017 ◽  
Vol 34 (9) ◽  
pp. 1947-1961 ◽  
Author(s):  
Marlos Goes ◽  
Elizabeth Babcock ◽  
Francis Bringas ◽  
Peter Ortner ◽  
Gustavo Goni
Keyword(s):  
Small Sample Size ◽  
Heat Content ◽  
Small Sample ◽  
Profile Data ◽  
Expendable Bathythermograph ◽  
Different Types ◽  
Long Term Trends ◽  
The Mean ◽  
The Impact

AbstractExpendable bathythermograph (XBT) data provide one of the longest available records of upper-ocean temperature. However, temperature and depth biases in XBT data adversely affect estimates of long-term trends of ocean heat content and, to a lesser extent, estimates of volume and heat transport in the ocean. Several corrections have been proposed to overcome historical biases in XBT data, which rely on constantly monitoring these biases. This paper provides an analysis of data collected during three recent hydrographic cruises that utilized different types of probes, and examines methods to reduce temperature and depth biases by improving the thermistor calibration and reducing the mass variability of the XBT probes.The results obtained show that the use of individual thermistor calibration in XBT probes is the most effective calibration to decrease the thermal bias, improving the mean thermal bias to less than 0.02°C and its tolerance from 0.1° to 0.03°C. The temperature variance of probes with screened thermistors is significantly reduced by approximately 60% in comparison to standard probes. On the other hand, probes with a tighter weight tolerance did not show statistically significant reductions in the spread of depth biases, possibly because of the small sample size or the sensitivity of the depth accuracy to other causes affecting the analysis.

scholarly journals A Systematic Review of Recommendations of Long-Term Strategies for Researchers Using Data Science Techniques

Computers ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 35
Author(s):  
Gilberto Ayala-Bastidas ◽  
Hector G. Ceballos ◽  
Francisco J. Cantu-Ortiz
Keyword(s):  
Systematic Review ◽  
Data Science ◽  
Process Mining ◽  
Research Strategies ◽  
Scientific Content ◽  
Open Research ◽  
Using Data ◽  
Long Term Impact ◽  
The Impact

The impact of the strategies that researchers follow to publish or produce scientific content can have a long-term impact. Identifying which strategies are most influential in the future has been attracting increasing attention in the literature. In this study, we present a systematic review of recommendations of long-term strategies in research analytics and their implementation methodologies. The objective is to present an overview from 2002 to 2018 on the development of this topic, including trends, and addressed contexts. The central objective is to identify data-oriented approaches to learn long-term research strategies, especially in process mining. We followed a protocol for systematic reviews for the engineering area in a structured and respectful manner. The results show the need for studies that generate more specific recommendations based on data mining. This outcome leaves open research opportunities from two particular perspectives—applying methodologies involving process mining for the context of research analytics and the feasibility study on long-term strategies using data science techniques.

Terrorism and tourism in Israel

2016 ◽  
Vol 23 (6) ◽  
pp. 1343-1352 ◽  
Author(s):  
Marion Karl ◽  
Gordon Winder ◽  
Alexander Bauer
Keyword(s):  
Time Lag ◽  
Research Model ◽  
Long Term Effects ◽  
Short Term ◽  
Event Tourism ◽  
Using Data ◽  
Terrorist Event ◽  
The Impact ◽  
The Relationship

While the relation between terrorism and tourism has been an important topic for tourism research, the questions whether terrorism affects tourism immediately and how long after a terrorism event tourism recovers are, as yet, not clearly answered. The aim of this article is to better understand the magnitude and temporal scale of the impact of terrorism on tourism. To this end, a research model differentiating between short-term and long-term effects of terrorism on tourism is developed and analyzed for the destination Israel using data on tourists from Germany. The results show both short-term and long-term impacts with a time lag between the terrorist event and the beginning of tourism decline of 1 or up to 6 months. An economic influence on the development of tourist arrivals was not detected, but seasonality plays an important role in the relationship between terrorism and tourism.

scholarly journals An analysis of factors influencing the development of Social enterprises in the Republic of Serbia

2020 ◽  
Vol 17 (2) ◽  
pp. 1-18
Author(s):  
Maja Ivanović-Đukić ◽  
Marija Petrović-Ranđelović ◽  
Miljana Talić
Keyword(s):  
Social Enterprises ◽  
Financial Resources ◽  
Exploratory Research ◽  
Legal Regulations ◽  
Factors Influencing ◽  
The Republic ◽  
Using Data ◽  
The Impact ◽  
Macroeconomic Environment

The paper investigates the impact of different factors on the establishment and development of social enterprises (SPs). The aim of this paper is to identify the key stimulants and restrictions of development of SPs in the Republic of Serbia, and to propose measures, the application of which can increase their long-term sustainability. The paper is based on exploratory research using data covering 27 interviews with founders of social enterprises in the Republic of Serbia. By applying the methods of regression analysis, it was found that favorable financial resources (especially grants) are the key stimulants for the establishment of social enterprises, while the enthusiasm of managers of social enterprises has the greatest impact on their development. It was found also that legal regulations and the macroeconomic environment, as well as difficulties in accessing the market, are serious restrictions on the establishment of social enterprises, while lack of knowledge in the field of marketing and management limit the development of social enterprises in the Republic of Serbia.

scholarly journals The Impact of Non-uniform Sampling on Stratospheric Ozone Trends Derived from Occultation Instruments

2017 ◽  
Author(s):  
Robert P. Damadeo ◽  
Joseph M. Zawodny ◽  
Ellis E. Remsberg ◽  
Kaley A. Walker
Keyword(s):  
Stratospheric Ozone ◽  
Primary Source ◽  
Data Sets ◽  
Sampled Data ◽  
Uniform Sampling ◽  
Ozone Trends ◽  
Long Term Trends ◽  
Non Uniform Sampling ◽  
The Impact

Abstract. This paper applies a recently developed technique for deriving long-term trends in ozone from sparsely sampled data sets to multiple occultation instruments simultaneously without the need for homogenization. The technique can compensate for the non-uniform temporal, spatial, and diurnal sampling of the different instruments and can also be used to account for biases and drifts between instruments. These problems have been noted in recent international assessments as being a primary source of uncertainty that clouds the significance of derived trends. Results show potential recovery trends of ~ 2–3 %/decade in the upper stratosphere at mid-latitudes, which are similar to other studies, and also how sampling biases present in these data sets can create differences in derived "recovery" trends of up to ~ 1 %/decade if not properly accounted for. Limitations inherent to all techniques (e.g., relative instrument drifts) and their impacts (e.g., trend differences up to ~ 2 %/decade) are also described and a potential path forward towards resolution is presented.

scholarly journals Investigation of the impact of the project office on the socio-economic development of the municipality

2021 ◽  
Vol 12 (1) ◽  
pp. 157-172
Author(s):  
Alla Yu. Trusova ◽  
Vladimir I. Aksenov
Keyword(s):  
Economic Development ◽  
Development Strategy ◽  
Scientific Article ◽  
Management Tools ◽  
Project Approach ◽  
Regional Development Strategy ◽  
Socio Economic Development ◽  
Long Term Trends ◽  
The Impact

The complexity of the socio-economic situation at all levels requires a detailed study of the regional development strategy issues and monitoring the implementation of presidential and government decrees. Various approaches to management were considered, for example, the national projects development implementation issues. National projecting, as a new tool for implementing state concepts, is an effective management method. The set of the project office functions provides control over the implementation of national projects at the level of development of municipalities of the Russian Federation. Historically, the level of socio-economic development of the territory has been measured and is measured using the identification of long-term trends in the development of key socio-economic indicators. The article presents a methodology that allows you to evaluate the effectiveness of project management tools since based on the results of its assessment, you can make informed management decisions and judge the effectiveness of the work of local authorities. Therefore, the aim of the scientific article was to develop an effective methodology that allows us to evaluate the effectiveness of the project office functions implemented in the management of the socio-economic development of the municipality. As a result of the study, systemic relationships were revealed of the impact of the project office on the indicators of the socio-economic development of the municipality, which was presented in the work as an important aspect of the study, the significance of which is due to the priorities of sustainable, balanced, competitive, integrated development of the Russian regions. In connection with the socio-economic policy pursued by the state, which requires speedy acceleration of the socio-economic development of municipalities, the effectiveness of the result of the application of the project approach in the municipal authorities was studied in detail.

scholarly journals THE IMPACT OF THE COVID-19 PANDEMIC ON THE PROFITABILITY OF LARGE COMMERICAL BANKS IN THE REPUBLIC OF NORTH MACEDONIA

2021 ◽  
Vol 14(63) (2) ◽  
pp. 79-84
Author(s):  
Fitim Deari ◽  
Keyword(s):  
Commercial Banks ◽  
Preliminary Evidence ◽  
Long Term Effects ◽  
Commerical Banks ◽  
The Republic ◽  
Using Data ◽  
The Impact ◽  
Profitability Ratios

The purpose of this study is to investigate the impact of the current Covid-19 pandemic on profitability ratios of large commercial banks in the Republic of North Macedonia. By using data over the period 2004 – 2020, ten profitability indicators are examined. These indicators are investigated by comparing their values before and during the Covid-19 pandemic. Overall, the study reveals a preliminary evidence that large commercial banks are affected by the Covid-19 pandemic. So far, profitability of large banks has not changed significantly due to Covid-19 and they keep satisfactory profitability levels. However, this impact should be investigated furthermore in next studies because the current pandemic has long-term effects.

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