scholarly journals Can critical temperatures be related to insect order

2009 ◽  
Vol 62 ◽  
pp. 399-399
Author(s):  
A. Arbab ◽  
M.R. McNeill
Keyword(s):  
Field Experiments ◽  
Nonlinear Models ◽  
Risk Assessments ◽  
Thermal Constant ◽  
Critical Temperatures ◽  
Insect Order ◽  
Development Temperature ◽  
The Relationship ◽  
Insect Phenology ◽  
Maximum Development

Insect phenology models are widely used for decision support in pest management and more recently in risk assessments During the last two decades numerous linear and nonlinear models have been used to describe insect development rates and estimate various critical temperatures (CT) including optimal development temperature (Topt) maximum development temperature (Tmax) minimum development temperature (Tmin) and thermal constant (K) (eg day degree requirements to complete development) Using a database comprising more than 600 species from laboratory and field experiments the relationship between CT for the six main insect orders Coleoptera Diptera Hymenoptera Lepidoptera Homoptera and Hemiptera was compared There were no significant differences (P>005) between Topt and Tmax for all orders but Tmin and K showed significant (P

scholarly journals Temperature dependent development of Phenacoccus solenopsis under laboratory conditions

2017 ◽  
Vol 21 (1) ◽  
pp. 25 ◽  
Author(s):  
Sanjeev Kumar ◽  
Ch. Kontodimas
Keyword(s):  
Nonlinear Models ◽  
Thermal Constant ◽  
Temperature Threshold ◽  
Critical Temperatures ◽  
Phenacoccus Solenopsis ◽  
Developmental Threshold ◽  
Cotton Mealybug ◽  
Lower Temperature Threshold ◽  
Lower Temperature ◽  
The Relationship

Cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) is an important cotton pest in Punjab, India. Development of the immature stages (four instars in female and five in male) of P. solenopsis was observed at nine constant temperatures (15, 18, 20, 25, 30, 34, 35, 38, 40°C). Using the linear model, the lower temperature threshold (tmin) for development was estimated to be 4.93 and 2.95°C and the thermal constant (K) was 333.33 and 454.54 degree days for female and male, respectively. In addition, three nonlinear models (Lactin, Bieri-1 and 3rd order polynomial) were tested to describe the relationship between temperature and development rate and to estimate the upper developmental threshold (tmax) and the optimum temperature for development (topt). Our results proved that the Bieri-1 and Lactin models and provided the best fit (r2 = 93,4 – 99,9%) and estimated accurately all the three critical temperatures, ranged tmin = 5.06 – 5.25°C, topt = 33.55 – 33.60°C, tmax = 39.99 – 40.00°C, for the total development of females and tmin = 2.82 – 3.16°C, topt = 34.01 – 34.04°C, tmax =40.00 – 40.10°C, for the total development of males.

Life table parameters of Iranian population, Tetranychus kanzawai (Acari: Tetranychidae) fed on soybean leaves 

2019 ◽  
Vol 24 (2) ◽  
pp. 231 ◽  
Author(s):  
Iman Hassanvand ◽  
Shahriar Jafari ◽  
Masoumeh Khanjani
Keyword(s):  
Life Table ◽  
Nonlinear Models ◽  
Developmental Rate ◽  
Developmental Time ◽  
Thermal Constant ◽  
Adult Longevity ◽  
Immature Stages ◽  
Tetranychus Kanzawai ◽  
Life Table Parameters ◽  
Critical Temperatures

The effects of six ambient temperatures (15, 20, 25, 30, 35 and 37.5ºC) on life table parameters of Tetranychus kanzawai Kishida (Tetranychidae) were studied under laboratory conditions on soybean (Glycine max (L.) Merrill). Total immature developmental time of females at the above-mentioned temperatures was 28.55, 16.34, 9.01, 6.96, 5.56 and 5.65 days, respectively. A linear and two nonlinear models of Lactin and SSI were fitted to developmental rate of immature stages of T. kanzawai to predict the developmental rate as a function of temperature, as well as to estimate the thermal constant (k) and critical temperatures. The estimated k for total immature developmental time of females and males was 134.58 and 126.74 DD, respectively. The estimated Topt and Tmax by Lactin model for overall immature stages were 36.20 and 40.70ºC, respectively. Intrinsic optimum temperature (TФ) and T1 (Topt) by SSI model for total immature stages was estimated to be 23.23 and 35.71ºC, respectively. Also the estimated TL and Th of SSI model for overall immature stage were 09.21 and 38.46ºC, respectively. The longest and shortest adult longevity was observed at 15°C (60.63 days), and 37.5°C (7.34 days), respectively. Mated females laid highest and lowest eggs at 25°C (237.96 eggs) and 37.5°C (30.54 eggs), respectively. The rm values ranged from 0.356 day-1 at 30°C to 0.089 day-1at 15°C. The highest value of R0 was 163.55 offspring female-1 at 25°C. The presented information in this study provided new perspective to better management of T. kanzawai on apple trees in Iran.

Simulation on Extrusion Comminution Model of Roller Press

2010 ◽  
Vol 156-157 ◽  
pp. 1702-1707
Author(s):  
Xiang Wen Cheng ◽  
Jinchao Liu ◽  
Qi Zhi Ding ◽  
Li Ming Song ◽  
Zhan Lin Wang
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Field Experiments ◽  
Size Ratio ◽  
Optimum Operating ◽  
Extrusion Force ◽  
Particle Size Ratio ◽  
Small Constant ◽  
Working Parameters ◽  
The Relationship

How to predict the relationship among particle size and among product size, to establish the relationship between the granularity and working parameters in the process of grinding and to determine the optimum operating parameters. With proposing BS squeeze crush model by L. Bass and the idea of roll surface division as the material uneven extrusion force are adopted. Based on field experiments the experimental data is analyzed, the select function and the breakage functions are fitted with MATLAB software, and obtaining their model. The comminution model is determined by the roller division. We obtain the model parameter through the experimental data. Through model analysis shows: the relationship between particle breakage and energy absorption, namely the smaller size of the same power, the lower broken; the breakage diminishes with the decrease of particle size ratio and it will be tending to a small constant when the smaller particle size ratio. The breakage functions rapidly decrease within ratio of between 0.2-0.7. This shows: the energy consumption will rapidly increase when the particle size of less than 0.2 in broken; the selection diminish with the decrease of particle size. Pressure (8-9MPa) should be the most appropriate value.

scholarly journals Eight Simple Guidelines for Improved Understanding of Transformations and Nonlinear Effects

2021 ◽  
pp. 109442812199190
Author(s):  
Mikko Rönkkö ◽  
Eero Aalto ◽  
Henni Tenhunen ◽  
Miguel I. Aguirre-Urreta
Keyword(s):  
Generalized Linear Model ◽  
Functional Form ◽  
Nonlinear Models ◽  
Nonlinear Effects ◽  
Recent Past ◽  
Organizational Research ◽  
Common Practices ◽  
Individual Variables ◽  
The Individual ◽  
The Relationship

Transforming variables before analysis or applying a transformation as a part of a generalized linear model are common practices in organizational research. Several methodological articles addressing the topic, either directly or indirectly, have been published in the recent past. In this article, we point out a few misconceptions about transformations and propose a set of eight simple guidelines for addressing them. Our main argument is that transformations should not be chosen based on the nature or distribution of the individual variables but based on the functional form of the relationship between two or more variables that is expected from theory or discovered empirically. Building on a systematic review of six leading management journals, we point to several ways the specification and interpretation of nonlinear models can be improved.

scholarly journals Interactions Between Chill-Hours and Degree-Days Affect Carpogenic Germination in Monilinia vaccinii-corymbosi

2001 ◽  
Vol 91 (1) ◽  
pp. 77-83 ◽  
Author(s):  
H. Scherm ◽  
A. T. Savelle ◽  
P. L. Pusey
Keyword(s):  
Laboratory Experiments ◽  
Field Experiments ◽  
Degree Days ◽  
Carpogenic Germination ◽  
Conditioning Period ◽  
Low Degree ◽  
Heating Degree Days ◽  
Relationship Of ◽  
High Degree ◽  
The Relationship

The relationship of cumulative chill-hours (hours with a mean temperature <7.2°C) and heating degree-days (base 7.2°C) to carpogenic germination of pseudosclerotia of Monilinia vaccinii-corymbosi, which causes mummy berry disease of blueberry, was investigated. In two laboratory experiments, pseudosclerotia collected from rabbiteye blueberry in Georgia were conditioned at 5 to 6°C for 26 to 1,378 h prior to placement in conditions favorable for germination and apothecium development. The number of chill-hours accumulated during the conditioning period affected the subsequent proportion of pseudosclerotia that germinated and produced apothecia, with the greatest incidence of carpogenic germination occurring after intermediate levels of chilling (≈700 chill-hours). The minimum chilling requirement for germination and apothecium production was considerably lower than that reported previously for pseudo-sclerotia from highbush blueberry in northern production regions. The rate of carpogenic germination was strongly affected by interactions between the accumulation of chill-hours and degree-days during the conditioning and germination periods; pseudosclerotia exposed to prolonged chilling periods, once transferred to suitable conditions, germinated and produced apothecia more rapidly (after fewer degree-days had accumulated) than those exposed to shorter chilling periods. Thus, pseudosclerotia of M. vaccinii-corymbosi are adapted to germinate carpogenically following cold winters (high chill-hours, low degree-days) as well as warm winters (low chill-hours, high degree-days). Results were validated in a combined field-laboratory experiment in which pseudosclerotia that had received various levels of natural chilling were allowed to germinate in controlled conditions in the laboratory, and in two field experiments in which pseudosclerotia were exposed to natural chilling and germination conditions. A simple model describing the timing of apothecium emergence in relation to cumulative chill-hours and degree-days was developed based on the experiments. The model should be useful for better timing of field scouting programs for apothecia to aid in management of primary infection by M. vaccinii-corymbosi.

scholarly journals Nitrogen management in wheat based on the normalized difference vegetation index (NDVI)

2018 ◽  
Vol 48 (9) ◽  
Author(s):  
André Luis Vian ◽  
Christian Bredemeier ◽  
Marcos Alexandre Turra ◽  
Cecília Paz da Silva Giordano ◽  
Elizandro Fochesatto ◽  
...  
Keyword(s):  
Technical Efficiency ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Field Experiments ◽  
Shoot Biomass ◽  
Sensor Field ◽  
N Dose ◽  
Plant Emergence ◽  
The Moment ◽  
The Relationship

ABSTRACT: Biomass production and nitrogen (N) accumulated in wheat shoots may be used for quantifying optimal topdressing nitrogen doses. The objective of this study was to develop and validate models for estimating the amount of biomass and nitrogen accumulated in shoots and the N topdressing dose of maximum technical efficiency in wheat using the normalized difference vegetation index (NDVI) measured by an active optical canopy sensor. Field experiments were carried out in two years and treatments consisted of N doses applied at plant emergence and as topdressing. NDVI, shoot biomass and N accumulated in shoots at the growth stage of six fully expanded leaves and grain yield were evaluated, being determined the topdressing N dose of maximum technical efficiency (DMTE). The NDVI was positively correlated to shoot biomass and N content in shoots and models for the relationship between these variables were developed and validated. The DMTE was negatively correlated with the NDVI value evaluated at the moment of N topdressing application. Thus, NDVI evaluation by an active optical canopy sensor can be used for nitrogen fertilization in variable rate, allowing the adjustment of applied N doses in different areas within a field.

Sustainability engagement’s impact on tourism sector performance: linear and nonlinear models

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Amina Buallay ◽  
Jasim Al-Ajmi ◽  
Elisabetta Barone
Keyword(s):  
Significant Relationship ◽  
Linear Models ◽  
Performance Indicator ◽  
Nonlinear Models ◽  
Sustainability Reporting ◽  
Analytical Framework ◽  
Content Type ◽  
Return On Equity ◽  
Using Data ◽  
The Relationship

PurposeThis study aims to investigate the relationship between the level of sustainability reporting and tourism sector’s performance (operational, financial and market).Design/methodology/approachUsing data culled from 1,375 observations from 37 different countries for ten years (2008–2017), an independent variable derived from the environmental, social and governance (ESG score) is regressed against dependent performance indicator variables (return on assets (ROA), return on equity (ROE) and Tobin's Q (TQ)). Two types of control variables complete the regression analysis in this study: firm-specific and macroeconomic.FindingsThe findings elicited from the empirical results of the linear models demonstrate that there is a significant relationship between ESG and operational performance (ROA) and market performance (TQ). However, there is no significant relationship between ESG and financial performance (ROE). Furthermore, the results of the nonlinear models suggest that the relationship between sustainability performance and firm's profitability and valuation is nonlinear (inverted U-shape).Originality/valueThe models in this study presents a valuable analytical framework for exploring sustainability reporting as a driver of performance in the tourism sector's economies. In addition, this study highlights the tourism sector's management lacunae manifesting in terms of the weak nexus between each component of ESG and tourism sector's performance.

Survival of Escherichia coli on Lettuce under Field Conditions Encountered in the Northeastern United States

2017 ◽  
Vol 80 (7) ◽  
pp. 1214-1221 ◽  
Author(s):  
Daniel L. Weller ◽  
Jasna Kovac ◽  
Sherry Roof ◽  
David J. Kent ◽  
Jeffrey I. Tokman ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Microbial Contamination ◽  
Field Conditions ◽  
Risk Assessments ◽  
Most Probable Number ◽  
Northeastern United States ◽  
Probable Number ◽  
E Coli ◽  
The Relationship ◽  
Sample Time

ABSTRACT Although wildlife intrusion and untreated manure have been associated with microbial contamination of produce, relatively few studies have examined the survival of Escherichia coli on produce under field conditions following contamination (e.g., via splash from wildlife feces). This experimental study was performed to estimate the die-off rate of E. coli on preharvest lettuce following contamination with a fecal slurry. During August 2015, field-grown lettuce was inoculated via pipette with a fecal slurry that was spiked with a three-strain cocktail of rifampin-resistant nonpathogenic E. coli. Ten lettuce heads were harvested at each of 13 time points following inoculation (0, 2.5, 5, and 24 h after inoculation and every 24 h thereafter until day 10). The most probable number (MPN) of E. coli on each lettuce head was determined, and die-off rates were estimated. The relationship between sample time and the log MPN of E. coli per head was modeled using a segmented linear model. This model had a breakpoint at 106 h (95% confidence interval = 69, 142 h) after inoculation, with a daily decrease of 0.70 and 0.19 log MPN for 0 to 106 h and 106 to 240 h following inoculation, respectively. These findings are consistent with die-off rates obtained in similar studies that assessed E. coli survival on produce following irrigation. Overall, these findings provide die-off rates for E. coli on lettuce that can be used in future quantitative risk assessments.

Temperature-dependent development of Amblyseius swirskii (Acari: Phytoseiidae) on Tetranychus urticae (Acari: Tetranychidae)

2020 ◽  
Vol 25 (3) ◽  
pp. 538-547 ◽  
Author(s):  
Azadeh Farazmand ◽  
Masood Amir-maafi ◽  
Remzi Atlihan
Keyword(s):  
Nonlinear Models ◽  
Information Criterion ◽  
Weather Conditions ◽  
Developmental Rate ◽  
Developmental Time ◽  
Thermal Constant ◽  
Temperature Threshold ◽  
Immature Stages ◽  
Amblyseius Swirskii ◽  
Wide Range

In this study, developmental time of Amblyseius swirskii Athias-Henriot feeding on immature stages of Tetranychus urticae Koch was evaluated at eight constant temperatures (15, 20, 25, 27.5, 30, 32.5, 35, and 37.5 °C) providing 60±5% RH and a photoperiod of 16 L: 8 D. Duration of the egg to adult developmental time decreased sharply with increasing temperature, except at 37.5°C. To describe the developmental rate of A. swirskii as a function of temperature, one linear and 9 nonlinear models (Logan-6, Logan-10, Lactin-1, Lactin-2, Briere-1, Briere-2, Analytis-3, Polynomial, and Equation-16) were fitted. The lower temperature threshold (T0) and the thermal constant (K) were estimated by the linear model for the total immature stage as 7.90 °C and 140.85 DD, respectively. Based on the Akaike Information Criterion (AIC) and R2adj, Polynomial, Analytis-3, Analytis-3, Logan-10 and Briere-2 were the best models for eggs, larvae, protonymphs, deutonymphs and total immature stages of A. swirskii, respectively. Our findings showed that development and predation of A. swirskii occurs in a wide range of temperatures. Therefore, this predatory mite could be applied in control of T. urticae in different weather conditions.

Nonlinear impact of World Heritage Sites on China’s tourism expansion

2020 ◽  
pp. 135481662090488
Author(s):  
Yu-Xia Lin ◽  
Ming-Hsiang Chen ◽  
Bi-Shu Lin ◽  
Shu-Yin Tseng ◽  
Ching-Hui (Joan) Su
Keyword(s):  
Nonlinear Models ◽  
World Heritage ◽  
Optimal Number ◽  
World Heritage Sites ◽  
Heritage Sites ◽  
Domestic Tourism ◽  
Inbound Tourism ◽  
The Impact ◽  
The Relationship ◽  
Instantaneous Effect

Using domestic tourism data (1999–2014) and inbound tourism data (1999–2016), this research applies linear and nonlinear models to investigate the impact of World Heritage Sites (WHS) on inbound and domestic tourism expansion (TE) in terms of tourist arrivals and tourism receipts and then tests whether or not the impact of WHS on TE is instant. The results show a notable influence of WHS on tourist arrivals and tourism receipts and identify several differences between the impacts of WHS on inbound and on domestic TE. Moreover, the relationship between WHS and TE exhibits an inverted U-shaped curve. The optimal number of WHS for TE is four, and there is a significant instantaneous effect of WHS on domestic TE. Differently, the impact of WHS on inbound tourism shows a 1-year lag. Lastly, we perform dynamic regressions as a robustness check and discussion and implications are provided.

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