scholarly journals Resource Partitioning of Scots Pine (Pinus sylvestris L.) by Pine Shoot Beetles in Stands under Stress Conditions

Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1336
Author(s):  
Andrzej Borkowski
Keyword(s):  
Scots Pine ◽  
Resource Partitioning ◽  
Multiple Linear Regression Model ◽  
Significant Degree ◽  
Sympatric Species ◽  
Site Quality ◽  
Explanatory Variables ◽  
Use Of Resources ◽  
Pine Shoot Beetles ◽  
Spatial Specialization

The pine shoot beetles Tomicus piniperda L. and T. minor Hartwig are sympatric species that occur on Scots pine in two habitats. Feeding by the beetles in tree crowns causes significant losses in tree growth and disturbs the crown’s proper development. A review of the subject literature showed that there had been no previous studies of interspecific competition in stands with different degrees of crown damage. The aim of this work was to assess the resource partitioning of stems by the two species in stands with damaged and undamaged crowns. Data were collected in the years 1992–2008 in stands containing Scots pine located at different distances from timber yards. A total of 259 natural traps were laid, and measurements of height and diameter at breast height were made for 900 pines. The surface area of each stem was divided into 20 equal sections by making a division lengthwise (into units) and laterally (into an upper and lower part). In total, 90,501 egg galleries of pine shoot beetles were counted on 9560 stem sections. Feeding by pine shoot beetles in the crowns of pines reduces site productivity and the nutritional suitability of stems. The results of niche segregation indicate pine shoot beetles exhibited spatial specialization in the use of resources. prefers the thicker part of the stem, and T. minor the thinner part. The population of T. piniperda on the trap logs was described using a multiple linear regression model with three explanatory variables. As a result of regression modelling, from the set of variables representing characteristics of habitats, trees and trap logs and the parameters of infestation, the following explanatory variables were selected: range of colonisation of a trap log (rc), site quality class (sqc), and crown undamaged (cu). The explanatory variables included in the MLRM model explain to a significant degree (p < 0.05) the niche breadth of T. piniperda on trap logs. In all validated plots, the mean real and model values for the niche of T. piniperda on the trap logs are similar (p > 0.5), confirming the high accuracy of the developed model.

Resource partitioning and overlap in three sympatric species of Ips bark beetles (Coleoptera: Scolytidae)

Oecologia ◽  
2001 ◽  
Vol 128 (3) ◽  
pp. 443-453 ◽  
Author(s):  
Bruce D. Ayres ◽  
Matthew P. Ayres ◽  
Mark D. Abrahamson ◽  
Stephen A. Teale
Keyword(s):  
Resource Partitioning ◽  
Bark Beetles ◽  
Sympatric Species

The U. S.-Canada Free Trade Agreement: Impact on the U. S. Steel Industry

1994 ◽  
Vol 38 (1) ◽  
pp. 53-61 ◽  
Author(s):  
Harold R. Williams ◽  
Thomas J. Botzman
Keyword(s):  
Free Trade ◽  
Multiple Linear Regression Model ◽  
Trade Agreement ◽  
Single Equation ◽  
Steel Mill ◽  
Iron And Steel ◽  
Explanatory Variables ◽  
Income Elasticities ◽  
Price And Income Elasticities ◽  
The Impact

This study empirically estimates the impact of the U. S.-Canada FTA on specific iron and steel exports and imports using quarterly data for the period January 1981 to December 1990. A single equation multiple linear regression model is used to quantify at the industry and industry segment levels the impact of the agreement. The dependent variables are the quantities of major steel products traded between the two nations. The explanatory variables include foreign price adjusted for the exchange rate and tariff rate, domestic price, and the industrial production index. Results include calculation of price and income elasticities, which vary considerably by industry segments. The impact of free trade, as modeled, varies widely from product to product. As such it has important implications not only for government policy and employment but also for the adjustment problems faced by both the large integrated steel mill and the minimill producers.

Another new, diminutive Rock Gecko (Cnemaspis Strauch) from Peninsular Malaysia and a discussion of resource partitioning in sympatric species pairs

Zootaxa ◽  
2010 ◽  
Vol 2569 (1) ◽  
pp. 55 ◽  
Author(s):  
L. LEE GRISMER ◽  
CHAN KIN ONN ◽  
EVAN QUAH ◽  
MOHD ABDUL MUIN ◽  
ANNA E. SAVAGE ◽  
...  
Keyword(s):  
New Species ◽  
Body Size ◽  
Endemic Species ◽  
Resource Partitioning ◽  
Sympatric Species ◽  
Southeast Asian ◽  
Peninsular Malaysia ◽  
Activity Period ◽  
Species Pairs

A new, diminutive species of Rock Gecko, Cnemaspis shahruli sp. nov. from Penang Island, Penang; Pulau Jerejak, Penang; Pulau Pangkor, Perak; and the adjacent mainland at Sungai Sedim, Kedah was previously confused with juveniles of the sympatric, endemic species C. affinis (Stoliczka) on Penang Island. Cnemaspis shahruli sp. nov. is diagnosed from all other Southeast Asian Cnemaspis on the basis of several unique aspects of squamation, coloration, and body size. It is proposed that this new species has a more extensive mainland distribution than is presented here based on its southernmost record on Pulau Pangkor, Perak. A pattern of resource partitioning on the basis of body size, habitat, and activity period among sympatric species pairs of Cnemaspis is discussed.

scholarly journals Statistical Modelling of the Capital Asset Pricing Model (CAPM)

2018 ◽  
Vol 7 (2) ◽  
pp. 146
Author(s):  
Silvi Qemo ◽  
Eahab Elsaid
Keyword(s):  
Linear Regression ◽  
Regression Model ◽  
Multiple Linear Regression ◽  
Linear Regression Model ◽  
Multiple Linear Regression Model ◽  
Statistical Modelling ◽  
Expected Returns ◽  
Explanatory Variables ◽  
Bid Ask Spread ◽  
Model Average

The purpose of this study is to derive a multiple linear regression model of the CAPM. More specifically, to test for other potential explanatory variables that can be added to the basic linear regression model for the expected returns on Apple Inc. The following explanatory variables were examined: share volume, outstanding shares, closing bid/ask spread, high/low spread and average spread. Using daily returns of Apple Inc. stock from 2007 till 2014 we were able to create a multiple linear regression model of CAPM that increase the R2 value from the basic linear regression model and enhances the amount of variability in the returns on an asset. This is an important modification that can help better forecast returns on assets.Keywords: CAPM; multiple linear regression model; average spread; variability in the returns

Effects of age and site quality on the distribution of biomass in Scots pine (

Trees ◽  
1996 ◽  
Vol 10 (4) ◽  
pp. 231 ◽  
Author(s):  
P. Vanninen ◽  
Hanna Ylitalo ◽  
Risto Sievänen ◽  
Annikki Mäkelä
Keyword(s):  
Scots Pine ◽  
Site Quality

scholarly journals Determinación de la humedad de suelo mediante regresión lineal múltiple con datos TerraSAR-X

2016 ◽  
pp. 73 ◽  
Author(s):  
G. García ◽  
M. Brogioni ◽  
V. Venturini ◽  
L. Rodriguez ◽  
G. Fontanelli ◽  
...  
Keyword(s):  
Land Surface ◽  
Multiple Linear Regression Model ◽  
Heat Fluxes ◽  
Distributed Data ◽  
Explanatory Variables ◽  
Regression Techniques ◽  
Geophysical Information ◽  
Electromagnetic Models ◽  
Agricultural Regions ◽  
Microwave Sensors

<p>The first five centimeters of soil form an interface where the main heat fluxes exchanges between the land surface and the atmosphere occur. Besides ground measurements, remote sensing has proven to be an excellent tool for the monitoring of spatial and temporal distributed data of the most relevant Earth surface parameters including soil’s parameters. Indeed, active microwave sensors (Synthetic Aperture Radar - SAR) offer the opportunity to monitor soil moisture (HS) at global, regional and local scales by monitoring involved processes. Several inversion algorithms, that derive geophysical information as HS from SAR data, were developed. Many of them use electromagnetic models for simulating the backscattering coefficient and are based on statistical techniques, such as neural networks, inversion methods and regression models. Recent studies have shown that simple multiple regression techniques yield satisfactory results. The involved geophysical variables in these methodologies are descriptive of the soil structure, microwave characteristics and land use. Therefore, in this paper we aim at developing a multiple linear regression model to estimate HS on flat agricultural regions using TerraSAR-X satellite data and data from a ground weather station. The results show that the backscatter, the precipitation and the relative humidity are the explanatory variables of HS. The results obtained presented a RMSE of 5.4 and a R<sup>2</sup>  of about 0.6</p>

scholarly journals Emergence levels of pine shoot beetles from roundwood piles of Scots pine and the cascading damage in the surrounding forests

Silva Fennica ◽  
2021 ◽  
Vol 55 (5) ◽  
Author(s):  
Markus Melin ◽  
Tiina Ylioja ◽  
Leena Aarnio ◽  
Katri Hamunen ◽  
Seppo Nevalainen ◽  
...  
Keyword(s):  
Pinus Sylvestris ◽  
Scots Pine ◽  
Bark Beetle ◽  
Bark Beetles ◽  
Coniferous Forests ◽  
The Future ◽  
Forest Legislation ◽  
Pine Shoot Beetles

Bark beetles are amongst the most aggressive pest agents of coniferous forests. Due to this, many boreal countries have designated laws aiming to lower the risk of bark beetle epidemics. Finland’s forest legislation has pre-emptive measures targeted against bark beetles, and for Scots pine ( L.), the law concerns pine shoot beetles ( spp.). This study used data collected around 25 piles of Scots pine roundwood that were harvested in the winter but left in the forest until the following November. Thus, the pine shoot beetles were able to use the piles for breeding. We assessed the number of emerged insects from the piles and the cascading damage they caused in the surrounding forests. All roundwood piles, regardless of their volume, were used by the beetles for breeding. Highest densities of beetle exit holes were found from the parts of the log with thick and intact bark. If the bark of the log was damaged by the harvester head, the number of beetles decreased significantly. Depending on the volume of the roundwood pile, the cascading damage (fallen shoots) was noticeable up to ca. 40–60 m from the roundwood pile. Storing of piles smaller than 50 m did not cause excess damage. The number of fallen shoots per tree was generally below the known thresholds for when growth losses can occur. However, the study was conducted in mature forests, and it can be assumed that the recorded damage levels would severely affect the growth of young pines, raising the question of where to store the roundwood. As with other bark beetles, the role of beetles as damage agents may change in the future, but based on this as well as past studies, the species can be viewed as a notable damage agents only around long-term wood storage sites in the current northern conditions.Pinus sylvestrisTomicus3Tomicus

scholarly journals Pemodelan Faktor Risiko Penyakit Campak pada Balita di Provinsi DKI Jakarta

2020 ◽  
Vol 9 (1) ◽  
pp. 1-11
Author(s):  
Ayu Annisa Rahmah ◽  
Itasia Dina Sulvianti ◽  
Cici Suhaeni ◽  
Bimandra Adiputra Djaafara
Keyword(s):  
Spatial Heterogeneity ◽  
Weighting Function ◽  
Immunization Coverage ◽  
Multiple Linear Regression Model ◽  
Spatial Location ◽  
Gaussian Kernel ◽  
Annual Rainfall ◽  
Explanatory Variables ◽  
The Difference ◽  
Gwr Model

Measles is one of the infectious caused by virus. The disease is easily transmitted and has become one of the main causes of child mortality especially toddlers. In 2016, Jakarta experienced the highest measles case in the last ten years and found the difference in the number of measles cases in each sub-district of Jakarta. This can be caused by the existence of effect of spatial location i.e. spatial heterogeneity. Geographically weighted regression (GWR) is a method that can be applied to address the presence of spatial heterogeneity in the process of developing the model. In this study, the weighting function used was the Gaussian kernel. The modelling process generated 42 local models at sub-district level. Explanatory variables that influence the incidence rate of measles in toddlers (Y) significantly are the percentage of immunization coverage measles (X1), the total annual rainfall (X4), and the percentage of the number of toddlers (X5). In this study, the GWR model is better than multiple linear regression model which were indicated by higher value of and smaller value of AIC.

Contagious Ecthyma in Black Bengal crossbred goats and its therapeutic management

2020 ◽  
Vol 5 (01) ◽  
pp. 145-149
Author(s):  
Pradeep Kumar Ram ◽  
Pramod Kumar
Keyword(s):  
Tamil Nadu ◽  
Plant Protection ◽  
Sustainable Use ◽  
Structured Interview ◽  
Primary Data ◽  
Banana Production ◽  
Explanatory Variables ◽  
Use Of Resources ◽  
Cultivation Practices ◽  
Human Labour

Banana is the most important fruit crop in India which requires the various cultivation practices. For carrying out those cultivation practices various energies are required to meet sustainable production. The main aim of this study was to find out the resource use efficiency estimation for banana production in Erode District of Tamil Nadu. Primary data was collected from 100 sample farmers using well structured interview schedule. The empirical results shows that except human labour, nitrogen, phosphorus and diesel remaining all other variables included in the model were positive and human labour, machine labour, nitrogen, potassium, FYM, plant protection chemicals, irrigation water, sucker and electricity were significant among other variables. Subsequently, increase in 1% use of inputs such as machine labour, potassium, electricity, sucker and plant protection chemicals would increase the yield of banana 0.15 per cent, 0.20 per cent, 0.02 per cent, 0.01 per cent and 0.01 per cent respectively and 79 per cent of the variations in banana yield were influenced by the explanatory variables. Likewise price fluctuation plays a major constraint among the banana farmers. This study suggested the banana farmers to use more amount of potassium and to reduce the usage of human labour and as well as nitrogen fertilizer for sustainable use of resources.

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