scholarly journals A REVIEW OF DAMPING-OFF OF DOUGLAS FIR SEEDLINGS IN BRITISH COLUMBIA

1954 ◽  
Vol 30 (4) ◽  
pp. 407-410 ◽  
Author(s):  
P. J. Salisbury

Except in new nurseries, damping-off in British Columbia forest nurseries has remained below serious levels. Modification of nursery practices has served to reduce losses. The use of a suitable, sandy cover soil has been effective. Lowered fertility of the soil, though a problem in itself, appears to decrease incidence of damping-off. The acidity of the soil in coast nurseries may have afforded some natural control of the disease. From investigations on the control of damping-off, there appears to be promise in the use of peat as a planting medium for stratified seed, and, based on experiments with unstratified seed, in the application of fungicides to cover soil. In view of the present low degree of the disease, there would appear to be an opportunity for research directed to the biology and control of fungi known to be capable of causing sudden outbreaks, without the urgent need of finding immediately effective control measures.

1974 ◽  
Vol 50 (5) ◽  
pp. 181-185 ◽  
Author(s):  
Andrew Radvanyi

Live trapping and tagging methods were employed to assess small mammal populations within two hardwood plantations in southern Ontario. Excessive girdling damage in past years to young planted trees necessitated an evaluation of rodent populations and development of effective control measures. The application of an anticoagulant rodenticide to oat groats bait broadcast over the study area at an ingredient cost of approximately three dollars per acre virtually wiped out the small mammals. Reinvasion from surrounding areas was, however, fairly rapid, particularly during late summer. Further research on longer term control measures using poisoned bait feeder stations is recommended.


2008 ◽  
Vol 13 (30) ◽  
Author(s):  
P Follin ◽  
L Dotevall ◽  
M Jertborn ◽  
Y Khalid ◽  
J Å Liljeqvist ◽  
...  

In January-February 2008, one imported case of measles initiated a series of exposures with around 380 nosocomial secondary contacts. Susceptible individuals were traced early and control measures were initiated that managed to limit the consequences considerably. Only four secondary cases were identified by the end of March. This minor outbreak illustrates the importance and efficiency of early control measures as well as the fact that the risk of measles outbreaks still exists in a country that has high measles, mumps, rubella vaccination coverage among children.


Weed Science ◽  
1979 ◽  
Vol 27 (1) ◽  
pp. 32-37 ◽  
Author(s):  
E. W. Stoller ◽  
L. M. Wax ◽  
F. W. Slife

Competition of yellow nutsedge (Cyperus esculentusL.) with corn (Zea maysL.) was evaluated in the field at various yellow nutsedge densities over a 3-yr period. A relationship between yellow nutsedge density (shoots/m2) and percentage yield reduction revealed an 8% yield reduction for every 100 shoots/m2. Two 3-yr studies were conducted to determine the most effective combination of preplant-incorporated, postemergence, or postemergence-directed treatments for yellow nutsedge control in corn. The preplant incorporated treatments were alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide], EPTC (S-ethyl dipropylthiocarbamate), or nothing; postemergence treatments were bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-(4) 3H-one 2,2-dioxide], two cultivations, or nothing; and the postemergence-directed treatments were ametryn [2-(ethylamino)-4-(isopropylamino)-6-(methylthio)-s-triazine] or nothing. One preplant-incorporated treatment of EPTC or alachlor prevented yield reductions from yellow nutsedge competition. When no control was practiced, yields were reduced 17% in a moderate yellow nutsedge infestation (initially infested with 300 tubers/m2) and 41% in a heavy infestation (initially infested with 1200 tubers/m2). Yields were reduced 7 to 8% in the moderate infestation when no preplant-incorporated treatments were used regardless of whether postemergence or postemergence-directed treatments were also used. After 1 yr, all control measures resulted in less tuber density than no control measures, but all control treatments had essentially similar tuber densities. After the second year, several herbicide treatments were as effective as hand weeding in reducing tuber density. At least 2 yr of effective control treatments were required to reduce tubers to 20% of the original density, and 3 yr of treatment to reduce the density to 15% of the original density. No combination of treatments, including hand weeding, eliminated tubers after 3 yr.


2012 ◽  
Vol 4 (1) ◽  
pp. 43-64 ◽  
Author(s):  
Rainer Vesterinen

AbstractThe present paper analyses the meaning of Spanish mood in factive contexts from a Cognitive Grammar perspective. It is argued that terms like assertion and presupposition do not explain the semantics of the subjunctive. Rather, they constitute an initial classification for finding a conceptually grounded explanation of it. The hypothesis is put forward that mood choice in factive contexts can be explained by the elaboration of Maldonado's (1995) notions of dominion and control. On the one hand, the conceptualizer has a low degree of effective control over the described event in presupposed contexts where the subjunctive mood occurs. On the other hand, presupposed contexts with the verb in the indicative mood equates with epistemic control over the described event. Thus, it is argued that the meaning of the subjunctive mood is related to the conceptualizer's epistemic dominion, and to the dominion of effective control. An additional analysis of the subjunctive mood in volitional, causative and perceptual contexts corroborates the initial claim.


2019 ◽  
Author(s):  
Junlong Li ◽  
Caiping Song ◽  
Jingya Yang ◽  
Jingmin Zheng ◽  
Lina Zhou ◽  
...  

Abstract The Ebola virus disease (EVD) is a highly contagious disease which is caused by the Ebola virus . Various measures were used to prevent and control the spread of EVD. The aim of this study was to find out the most critical measures to prevent and control the spread of EVD. Both mathematical modeling and comparative analysis were used to explore the development process of EVD outbreak in Guinea, Liberia and Sierra Leone. The results of comparative analysis showed quarantined individuals before infection (R 2 = 0.848, ε = 1.012), safe burial teams (R 2 = 0.772, ε = 0.385), and the Ebola treatment units (ETU) bed (R 2 = 0.690, ε = 0.432) could significantly influence the incidence of EVD which were consistent with the results of mathematical modeling. These findings indicted that a timely and effective quarantine played a significant role in preventing and controlling the spread of EVD, and the findings would help us prevent and control the epidemic outbreak of new infectious disease in the future.


2001 ◽  
Vol 126 (3) ◽  
pp. 335-341 ◽  
Author(s):  
J. M. COWDEN ◽  
S. AHMED ◽  
M. DONAGHY ◽  
A. RILEY

On Friday, 22 November 1996, the microbiologist at a hospital in Lanarkshire, Scotland, identified presumptive Escherichia coli O157 in faecal specimens submitted by three patients with bloody diarrhoea, and confirmed its presence in one. Over the next 6 h, 12 more potential cases were identified. Investigations first indicated then confirmed a single food premises as the source of infection. Effective control measures were applied promptly. The outbreak was declared over on 20 January 1997, by which time 512 cases had been identified, and infection with the outbreak strain confirmed in 279. Twenty deaths occurred in cases during the outbreak and there were two more in cases during 1997. Seventeen of these deaths resulted from the outbreak. This paper describes the outbreak's epidemiological investigation, referring to other investigations, and control measures, where appropriate.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xia Wang ◽  
Qian Li ◽  
Xiaodan Sun ◽  
Sha He ◽  
Fan Xia ◽  
...  

Abstract Background The COVID-19 pandemic is complex and is developing in different ways according to the country involved. Methods To identify the key parameters or processes that have the greatest effects on the pandemic and reveal the different progressions of epidemics in different countries, we quantified enhanced control measures and the dynamics of the production and provision of medical resources. We then nested these within a COVID-19 epidemic transmission model, which is parameterized by multi-source data. We obtained rate functions related to the intensity of mitigation measures, the effective reproduction numbers and the timings and durations of runs on medical resources, given differing control measures implemented in various countries. Results Increased detection rates may induce runs on medical resources and prolong their durations, depending on resource availability. Nevertheless, improving the detection rate can effectively and rapidly reduce the mortality rate, even after runs on medical resources. Combinations of multiple prevention and control strategies and timely improvement of abilities to supplement medical resources are key to effective control of the COVID-19 epidemic. A 50% reduction in comprehensive control measures would have led to the cumulative numbers of confirmed cases and deaths exceeding 590,000 and 60,000, respectively, by 27 March 2020 in mainland China. Conclusions Multiple data sources and cross validation of a COVID-19 epidemic model, coupled with a medical resource logistic model, revealed the key factors that affect epidemic progressions and their outbreak patterns in different countries. These key factors are the type of emergency medical response to avoid runs on medical resources, especially improved detection rates, the ability to promote public health measures, and the synergistic effects of combinations of multiple prevention and control strategies. The proposed model can assist health authorities to predict when they will be most in need of hospital beds and equipment such as ventilators, personal protection equipment, drugs, and staff.


2020 ◽  
Vol 14 (07) ◽  
pp. 696-698
Author(s):  
Xiaoyan Zhang ◽  
Yuxuan Wang

Different countries have employed various strategies for controlling the coronavirus disease (COVID-19) pandemic because there is no consensus regarding effective control measures in the literature. Epidemic control strategies can be classified into two types based on their characteristics. The first type is the “severe acute respiratory syndrome (SARS)-like epidemic control strategy,” i.e., containment. The second type is the “influenza pandemic-like epidemic control strategy” (flu pandemic-like strategy), i.e., mitigation. This paper presents a comparative analysis on the prevention and control strategies for COVID-19 in different countries to provide a reference to control the further spread of the pandemic.


2019 ◽  
Vol 41 (1) ◽  
pp. 130-144
Author(s):  
Rodrigo Macedo Couto ◽  
Otavio T Ranzani ◽  
Eliseu Alves Waldman

Abstract Zoonotic tuberculosis is a reemerging infectious disease in high-income countries and a neglected one in low- and middle-income countries. Despite major advances in its control as a result of milk pasteurization, its global burden is unknown, especially due the lack of surveillance data. Additionally, very little is known about control strategies. The purpose of this review was to contextualize the current knowledge about the epidemiology of zoonotic tuberculosis and to describe the available evidence regarding surveillance and control strategies in high-, middle-, and low-income countries. We conducted this review enriched by a One Health perspective, encompassing its inherent multifaceted characteristics. We found that the burden of zoonotic tuberculosis is likely to be underreported worldwide, with higher incidence in low-income countries, where the surveillance systems are even more fragile. Together with the lack of specific political commitment, surveillance data is affected by lack of a case definition and limitations of diagnostic methods. Control measures were dependent on risk factors and varied greatly between countries. This review supports the claim that a One Health approach is the most valuable concept to build capable surveillance systems, resulting in effective control measures. The disease characteristics and suggestions to implement surveillance and control programs are discussed.


mSphere ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Xianguang Yang ◽  
Xuelin Chen ◽  
Cuihong Ding ◽  
Zhibo Bai ◽  
Jingyi Zhu ◽  
...  

ABSTRACT The objective was to analyze the longitudinal distribution, epidemiological characteristics, and local prevention and control measures of coronavirus disease 2019 (COVID-19) in six cities in Henan Province, China, from 21 January 2020 to 17 June 2020: Xinyang City (including Gushi County), Nanyang City (including Dengzhou City), Zhumadian City (including Xincai County), Zhengzhou City (including Gongyi City), Puyang City, and Anyang City (including Hua County). Data were collected and analyzed through the COVID-19 information published on the official websites of the health commissions in the six selected cities of Henan Province. As of 17 June 2020, the cumulative incidence rate of COVID-19 in Henan Province was 1.33/100,000, the cumulative cure rate was 98.27%, the cumulative mortality rate was 1.73%, the age range of diagnosed cases was 5 days to 85 years old, and the male-to-female ratio was 1.09:1. The confirmed cases of COVID-19 in Henan Province were mainly imported cases from Hubei, accounting for 87.74% of all cases, of which the highest proportion was 70.50% in Zhumadian. The contact cases and local cases increased in a fluctuating manner over time. In this paper, epidemiological characteristics of COVID-19 in Henan Province were analyzed from the onset of the outbreak to the effective control within 60 days, and effective and distinctive prevention and control measures in various cities were summarized to provide a favorable useful reference for the further formulation and implementation of epidemic prevention and control and a valuable theoretical basis for effectively avoiding a second outbreak. IMPORTANCE Epidemic prevention and control in China have entered a new stage of normalization. This article analyzes the epidemiological characteristics of COVID-19 in Henan Province and summarizes the effective disease prevention and control means and measures at the prefecture level; the normalized private data provide a theoretical reference for the formulation and conduct of future prevention and control work. At the same time, these epidemic prevention and control findings can also be used for reference in other countries and regions.


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