Ability of Delphastus catalinae (Coleoptera: Coccinellidae), a Predator of Whiteflies (Homoptera: Aleyrodidae), to Survive Mild Winters

2007 ◽  
Vol 42 (2) ◽  
pp. 163-173 ◽  
Author(s):  
Alvin M. Simmons ◽  
Jesusa C. Legaspi
Keyword(s):  
South Carolina ◽  
Pupal Stage ◽  
Adult Survival ◽  
Adult Longevity ◽  
Feral Populations ◽  
Winter Temperatures ◽  
The Usa ◽  
Southern Florida ◽  
The Impact

Delphastus catalinae (Horn) (Coleoptera: Coccinellidae) is a predator of whiteflies and is sold by commercial insectaries to help manage Bemisia tabaci (Gennadius). This beetle is tropical in origin, but feral populations in the USA are known to persist in southern California and in central and southern Florida. Field populations of D. catalinae are not known to occur in northern Florida, GA, or South Carolina, and there has not been any report of field releases in these areas. A study was conducted to determine the ability of D. catalinae to survive in regions with mild winters where B. tabaci survives year-round, such as coastal South Carolina and northern Florida. Delphastus catalinae was sampled in field cages from December to April in 2002–2004. Only a few individuals were collected at the end of each winter. In the laboratory, at a constant temperature of 15°C, adult survival was up to 9 months (269 d), whereas survival was up to 16 d at 5°C. Without food, adult longevity was decreased by about 90%. A sample of the population from a laboratory test indicated that old females (at least 242 d) produced viable eggs. Eggs held at 5°C did not hatch, whereas 48% of those held at 15°C hatched. Conversely, 98% of eggs held at 25°C hatched. At 15°C, none of the larvae survived to the pupal stage, whereas at 25°C, 86% of the larvae survived to the adult stage. Winter temperatures near freezing may result in excessive D. catalinae mortality and few or no survivals at the end of the winter. These results help define the impact of long-term low temperatures on the northern geographical limit of D. catalinae and will aid in whitefly management decisions regarding this predator.

scholarly journals The relationship between corporate governance and firm performance revisited: where do we stand?

2010 ◽  
Vol 7 (3) ◽  
pp. 124-137 ◽  
Author(s):  
Stefan Hilger
Keyword(s):  
Corporate Governance ◽  
Business Models ◽  
Corporate Performance ◽  
Holistic Approach ◽  
Governance Mechanisms ◽  
Governance Practices ◽  
The Usa ◽  
The Impact ◽  
The Relationship

How is corporate governance measured, and what is the relationship between corporate governance mechanisms and corporate performance? This paper aims to shed light on these questions by providing an overview of the most important research findings in this area with a focus on the USA and Germany. My analysis gives rise to the following remarks. First, studies examining the impact of singles governance mechanisms are inconclusive and mixed in their findings, and especially the question of causality is still unanswered. Second, when a holistic approach is used, the proposition that good corporate governance enhances long-term performance is supported. However, corporate governance practices alone cannot assure long-term corporate performance and good standards of corporate governance are no substitute for the solidity of business models.

scholarly journals The effects of ownership concentration on sustainability: A case of listed firms from USA, UK and German

2017 ◽  
Vol 14 (3) ◽  
pp. 113-121 ◽  
Author(s):  
Zahid Irshad Younas ◽  
Christian Klein ◽  
Bernhard Zwergel
Keyword(s):  
Firm Growth ◽  
Ownership Concentration ◽  
Direct Role ◽  
Listed Firms ◽  
Concentrated Ownership ◽  
The Usa ◽  
National Trends ◽  
Different Characteristics ◽  
The Impact

Concentrated ownership has been speculated to play a direct role in leading firms to focus more on long-term sustainability. Concentrated ownership, however, can take many different forms, with some forms more common in certain countries, and we posit that the specific form of ownership mediates the impact on sustainability. Additionally, we posit that firms operating at different scales have fundamentally different characteristics which can further impact this relationship. Analyzing a sample of firms from the USA, UK, and Germany using Arellano- Bond GMM, we investigate the relationship between ownership concentration, firm growth and sustainability measures comparatively. Our results show that these relationships are not linear, but are rather dependent on the prevalent form of ownership concentration (determined by country) and the scale (small, medium or large) of the firm. Approaches to sustainability appear to be influenced by not just the owners / investors but also by the type of control and broader contexts, explaining differing national trends.

Institutional volume affects long-term survival following lung transplantation in the USA

2019 ◽  
Vol 56 (2) ◽  
pp. 271-276 ◽  
Author(s):  
Arman Kilic ◽  
Thomas G Gleason ◽  
Hiroshi Kagawa ◽  
Ahmet Kilic ◽  
Ibrahim Sultan
Keyword(s):  
Lung Transplantation ◽  
High Volume ◽  
Term Survival ◽  
Long Term Survival ◽  
Kaplan Meier ◽  
The Usa ◽  
Institutional Volume ◽  
Low Volume ◽  
The Impact

Abstract OBJECTIVES The aim of this study was to evaluate the impact of institutional volume on long-term outcomes following lung transplantation (LTx) in the USA. METHODS Adults undergoing LTx were identified in the United Network for Organ Sharing registry. Patients were divided into equal size tertiles according to the institutional volume. All-cause mortality following LTx was evaluated using the risk-adjusted multivariable Cox regression and the Kaplan–Meier analyses, and compared between these volume cohorts at 3 points: 90 days, 1 year (excluding 90-day deaths) and 10 years (excluding 1-year deaths). Lowess smoothing plots and receiver-operating characteristic analyses were performed to identify optimal volume thresholds associated with long-term survival. RESULTS A total of 13 370 adult LTx recipients were identified. The mean annual centre volume was 33.6 ± 20.1. After risk adjustment, low-volume centres were found to be at increased risk for 90-day mortality, [hazard ratio (HR) 1.56, P < 0.001], 1-year mortality excluding 90-day deaths (HR 1.46, P < 0.001) and 10-year mortality excluding 1-year deaths (HR 1.22, P < 0.001). These findings persisted when the centre volume was modelled as a continuous variable. The Kaplan–Meier analysis also demonstrated significant reductions in survival at each of these time points for low-volume centres (each P < 0.001). The 10-year survival conditional on 1-year survival was 37.4% in high-volume centres vs 28.0% in low-volume centres (P < 0.001). The optimal annual volume threshold for long-term survival was 26 LTx/year. CONCLUSIONS The institutional volume impacts long-term survival following LTx, even after excluding deaths within the first post-transplant year. Identifying the processes of care that lead to longer survival in high-volume centres is prudent.

The Locked Cage

2021 ◽  
pp. 162-174
Author(s):  
Kenya Johns ◽  
Natasha Barnes
Keyword(s):  
School System ◽  
Mass Incarceration ◽  
Traumatic Experiences ◽  
Academic Environment ◽  
It Impacts ◽  
The Family ◽  
Negative Effect ◽  
The Usa ◽  
The Impact

This chapter aims to discuss the on-going problems of mass incarceration within the USA and the impact it has on the family and the school system. Mass incarceration is a societal concern because it impacts those that are incarcerated and the families that they leave behind outside the cage. Those that are parents and are incarcerated not only have to deal with their decisions, their children do as well. It is estimated that more than 1.7 million children within the USA have experienced a parent or caregiver being incarcerated. Incarceration can have a negative effect on the students development within the classroom, leading to long-term traumatic experiences and negative behavioral, emotional academic performances within the classroom. This chapter explores the impact it has on the students and academic environment while provide tools to best support these students and families.

scholarly journals The Impact of the Global Financial Crisis, Does It Sustain?

2016 ◽  
Vol 8 (10) ◽  
pp. 82 ◽  
Author(s):  
Bashar Al-Zu'bi ◽  
Hussein Salameh ◽  
Qasim Mousa Abu Eid
Keyword(s):  
Financial Crisis ◽  
Stock Market ◽  
Global Financial Crisis ◽  
Stock Market Index ◽  
The World ◽  
The Usa ◽  
Short And Long Term ◽  
The Global Financial Crisis ◽  
The Impact

<p>This paper studies the short and long term relationship between S&amp;P500 USA stock market index and the stock market indices of 30 countries around the world over the period June 2010-April 2015. We implement OLS regression and use error correction model to examine the short and long term relationship between the variables. Empirically, we find that there is a relationship on the short and long term between S&amp;P500 and the indices of 27 countries from East Asia, Europe, Latin America, Middle East as well as the countries of Australia and Canada. These results conclude that the global financial crisis of 2007-2008 significantly and lengthy increased the already high level of co-movement between the USA financial market and the observed stock market for 27 countries around the world. The findings from our research are important; however, we believe that further research based on our findings is necessary.</p>

scholarly journals Lethal and sub-lethal effects of low-temperature exposures on Halyomorpha halys (Hemiptera: Pentatomidae) adults before and after overwintering

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Davide Scaccini ◽  
Luka Vanishvili ◽  
Paola Tirello ◽  
Vaughn M. Walton ◽  
Carlo Duso ◽  
...  
Keyword(s):  
Low Temperature ◽  
Cold Exposure ◽  
Mortality Rates ◽  
Adult Survival ◽  
Adult Longevity ◽  
Halyomorpha Halys ◽  
Stink Bug ◽  
Spring Frost ◽  
Nutrient Index ◽  
The Impact

Abstract Cold winter temperatures can influence insects’ survival in temperate zones. Brown marmorated stink bug, Halyomorpha halys (Stål) overwinters as adults in natural and human-made structures. In this study, we characterized low temperature mortality rates of H. halys adults that were either entering (ENA) or exiting (EXA) overwintering microhabitats. We considered the effect of different duration of cold exposure on mortality. We determined the impact of insect nutritional status and weight on cold tolerance. We additionally evaluated the effects of cold exposure on H. halys adult longevity and fecundity. Mortality of ENA and EXA adults was determined for 6 h and 2 h periods at − 2.5 °C and 2.5 °C respectively. EXA adults displayed higher mortality rates compared to ENA individuals at the low-temperature regimes. Halyomorpha halys adult survival rate was higher when their nutrient index (EXA individuals only) and weight were high. Low-temperature exposure increased longevity, but reduced fecundity of ENA females. The data further highlight how extreme spring frost events can result in significantly increased mortality levels of H. halys adults.

scholarly journals Shareholder empowerment, steps forward and steps back

2019 ◽  
Vol 27 (2) ◽  
pp. 169-196
Author(s):  
Saad Almohammed Alrayes
Keyword(s):  
Global Financial Crisis ◽  
Effective Means ◽  
Fiduciary Duty ◽  
Content Type ◽  
Shareholder Engagement ◽  
The Usa ◽  
The Global Financial Crisis ◽  
The Uk ◽  
The Impact

Purpose The global financial crisis of 2007-2008 prompted a significant debate on corporate governance and shareholder empowerment. A question arises as to whether shareholders ought to be further empowered to have a greater influence over the companies’ activities. Yet, it is not self-evident that shareholder empowerment ensures better-run companies’ corporate activities. Thus, the purpose of this paper is to critically examine, identify and explain the corporate regulation forms and control collectively to evaluate the effectiveness of shareholder empowerment fully. Design/methodology/approach To do so, this paper sets out a comparative analysis approach between two jurisdictions, the UK and Delaware in the USA. The paper further addresses by undertaking three case studies; Barclays Plc which illustrated the Comply or Explain role, AVIVA (2012) that concentrated on the impact of the shareholder revolt, and the case of Hills Stores Co. v. Bozic (2000), which involved a claim brought by shareholders on the grounds of a breach of fiduciary duty. Findings This paper argues that the shareholder empowerment theoretically provides an effective means through which corporate activities can be regulated. However, to do this, account must be taken that a distinction should be made between long-term and short-term investors to encourage shareholder engagement by responsible long-term investors. Furthermore, the shareholders can exercise their powers effectively and influence the Board’s decision to award executive compensation. Originality/value This paper offered two distinct contributions: assessing whether in times of crisis shareholder empowerment represents a way to regulate corporate activities and by assessing the distinction between the perception of shareholder empowerment and the reality in practice.

A survey of public scientific literacy in China

1993 ◽  
Vol 2 (1) ◽  
pp. 21-38 ◽  
Author(s):  
Zhongliang Zhang ◽  
Jiansheng Zhang
Keyword(s):  
Scientific Literacy ◽  
Developed Countries ◽  
Basic Component ◽  
The Usa ◽  
Scientific Terms ◽  
Level Of Understanding ◽  
The Uk ◽  
The Impact ◽  
Chinese Public

There is growing recognition in developed countries that public scientific literacy is a basic component of long-term social and economic growth. In recent years, surveys of public scientific literacy have been conducted in the USA, the UK and elsewhere, and various efforts are being made to improve the level of public scientific literacy. The first survey of Chinese public scientific literacy was conducted in September 1990. This paper reports a portion of the statistical results of that survey. It reveals the Chinese public's level of understanding of scientific terms and methods, scientific conclusions, and attitudes towards the impact of science and technology on society. Comparisons are also made with survey data from the USA and the UK.

scholarly journals Does elevated CO2 affect the biological aspects of Liriomyza sativae in melon plants?

2021 ◽  
Vol 42 (4) ◽  
pp. 2151-2162
Author(s):  
Jéssica de Oliveira Santos ◽  
◽  
Francislene Angelotti ◽  
Tiago Cardoso da Costa-Lima ◽  
◽  
...  
Keyword(s):  
Developmental Stages ◽  
Carbon Dioxide Concentration ◽  
Co2 Concentration ◽  
Adult Survival ◽  
Adult Longevity ◽  
Immature Stages ◽  
Liriomyza Sativae ◽  
Co2 Concentrations ◽  
Biological Aspects ◽  
The Impact

An increase in the carbon dioxide concentration (CO2) in the atmosphere has occurred in recent years, influencing the different biological aspects of herbivorous insects. The present study aimed to evaluate the effect of CO2 increase on the biological aspects of Liriomyza sativae Blanchard leafminer in melon plants. For this, two experiments were carried out: (i) to evaluate the effect of melon plants grown in CO2-enriched environments on the immature developmental stages of L. sativae and L. sativae adult longevity, and (ii) to verify the impact of increased CO2 concentration on L. sativae adult survival, feeding punctures, and oviposition. The experiments were carried out in growth chambers maintained in the temperature regime of 20-26-33 °C (simulating the minimum, average, and maximum daily temperature) and under two CO2 concentrations (400 ppm and 770 ppm). The immature stages and the egg-adult period of L. sativae were longer when they developed on plants grown in high CO2 levels (770 ppm), but no difference in adult longevity was observed. The viability of the immature phases was not different between the two CO2 concentrations. Furthermore, there was no difference in the number of eggs and feeding punctures between treatments. Thus, the increase in CO2 concentration prolongs the duration of the immature stages of L. sativae; however, it does not affect their viability. Adult survival, fertility, and feeding punctures were also unmodified by the environment enriched with CO2.

scholarly journals Assessing the impacts of global economic policy uncertainty and the long-term bond yields on oil prices

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Oguzhan Ozcelebi
Keyword(s):  
Economic Activity ◽  
Oil Prices ◽  
Policy Uncertainty ◽  
Government Bond ◽  
Bond Yields ◽  
Content Type ◽  
Economic Policy Uncertainty ◽  
The Usa ◽  
The Impact

Purpose Might the impact of the global economic policy uncertainty (GEPU) and the long-term bond yields on oil prices be asymmetric? This paper aims to consider the effects of the GEPU and the US long-term government bond yields on oil prices using quantile-based analysis and nonlinear vector autoregression (VAR) model. The author hypothesized whether the negative and positive changes in the GEPU and the long-term bond yields of the USA have different effects on oil prices. Design/methodology/approach To address this question, the author uses quantile cointegration model and the impulse response functions (IRFs) of the censored variable approach of Kilian and Vigfusson (2011). Findings The quantile cointegration test showed the existence of non-linear cointegration relationship, whereas Granger-causality analysis revealed that positive/negative variations in GEPU will have opposite effects on oil prices. This result was supported by the quantile regression model’s coefficients and nonlinear VAR model’s IRFs; more specifically, it was stressed that increasing/decreasing GEPU will deaccelerate/accelerate global economic activity and thus lead to a fall/rise in oil prices. On the other hand, the empirical models indicated that the impact of US 10-year government bond yields on oil prices is asymmetrical, while it was found that deterioration in the borrowing conditions in the USA may have an impact on oil prices by slowing down the global economic activity. Originality/value As a robustness check of the quantile-based analysis results, the slope-based Mork test is used.

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