scholarly journals Increasing Effectiveness of Genetically Modifying Mosquito Populations: Risk Assessment of Releasing Blood-Fed Females

Author(s):  
Siyang Xia ◽  
Jonah Ury ◽  
Jeffrey R. Powell

Releasing mosquito refractory to pathogens has been proposed as a means of controlling mosquito-borne diseases. A recent modeling study demonstrated that instead of the conventional male-only releases, adding blood-fed females to the release population could significantly increase the program’s efficiency, hastening the decrease in disease transmission competence of the target mosquito population and reducing the duration and costs of the release program. However, releasing female mosquitoes presents a short-term risk of increased disease transmission. To quantify this risk, we constructed a Ross–MacDonald model and an individual-based stochastic model to estimate the increase in disease transmission contributed by the released blood-fed females, using the mosquito Aedes aegypti and the dengue virus as a model system. Under baseline parameter values informed by empirical data, our stochastic models predicted a 1.1–5.5% increase in dengue transmission during the initial release, depending on the resistance level of released mosquitoes and release size. The basic reproductive number (R0) increased by 0.45–3.62%. The stochastic simulations were then extended to 10 releases to evaluate the long-term effect. The overall reduction of disease transmission was much greater than the number of potential infections directly contributed by the released females. Releasing blood-fed females with males could also outperform conventional male-only releases when the release strain is sufficiently resistant, and the release size is relatively small. Overall, these results suggested that the long-term benefit of releasing blood-fed females often outweighs the short-term risk.

2003 ◽  
Vol 182 (5) ◽  
pp. 412-419 ◽  
Author(s):  
Peter J. Cooper ◽  
Lynne Murray ◽  
Anji Wilson ◽  
Helena Romaniuk

BackgroundPsychological interventions for postnatal depression can be beneficial in the short term but their longer-term impact is unknown.AimsTo evaluate the long-term effect on maternal mood of three psychological treatments in relation to routine primary care.MethodWomen with post-partum depression (n=193) were assigned randomly to one of four conditions: routine primary care, non-directive counselling, cognitive–behavioural therapy or psychodynamic therapy. They were assessed immediately after the treatment phase (at 4.5 months) and at 9, 18 and 60 months post-partum.ResultsCompared with the control, all three treatments had a significant impact at 4.5 months on maternal mood (Edinburgh Postnatal Depression Scale, EPDS). Only psychodynamic therapy produced a rate of reduction in depression (Structured Clinical Interview for DSM–III–R) significantly superior to that of the control. The benefit of treatment was no longer apparent by 9 months post-partum. Treatment did not reduce subsequent episodes of post-partum depression.ConclusionsPsychological intervention for post-partum depression improves maternal mood (EPDS) in the short term. However, this benefit is not superior to spontaneous remission in the long term.


2021 ◽  
Vol 25 (3) ◽  
pp. 628-644
Author(s):  
Andreas Musolff

(How) Can the use of hyperbole in metaphorical idioms and scenarios contribute to an increase in emotionalisation of public debates? Using a research corpus of quotations from British politicians speeches and interviews and of press texts 2016-2020, this paper investigates hyperbolic formulations in Brexit-related applications of the proverb You cannot have your cake and eat it and related scenarios of national liberation, which appear to have strongly boosted emotionalised public debates. For instance, Brexit proponents reversal of the cake proverb into the assertion, We can have our cake and eat it, and their figurative interpretation of Brexit as a war of liberation (against the EU) triggered highly emotional reactions: triumphant affirmation among followers, fear and resentment among opponents. The paper argues that the combination of figurative speech (proverb, metaphor) with hyperbole heightened the emotional and polemical impact of the pro-Brexit argument. Whilst this effect may be deemed to have been rhetorically successful in the short term (e.g. in referendum and election campaigns), its long-term effect on political discourse is more ambivalent, for it leads to a polarisation and radicalisation of political discourse in Britain (as evidenced, for instance, in the massive use of hyperbole in COVID-19 debates). The study of hyperbole as a means of emotionalisation thus seems most promising as part of a discourse-historical investigation of socio-pragmatic effects of figurative (mainly, metaphorical) language use, rather than as an isolated, one-off rhetorical phenomenon.


Author(s):  
A. George Maria Selvam ◽  
Jehad Alzabut ◽  
D. Abraham Vianny ◽  
Mary Jacintha ◽  
Fatma Bozkurt Yousef

Towards the end of 2019, the world witnessed the outbreak of Severe Acute Respiratory Syndrome Coronavirus-2 (COVID-19), a new strain of coronavirus that was unidentified in humans previously. In this paper, a new fractional-order Susceptible–Exposed–Infected–Hospitalized–Recovered (SEIHR) model is formulated for COVID-19, where the population is infected due to human transmission. The fractional-order discrete version of the model is obtained by the process of discretization and the basic reproductive number is calculated with the next-generation matrix approach. All equilibrium points related to the disease transmission model are then computed. Further, sufficient conditions to investigate all possible equilibria of the model are established in terms of the basic reproduction number (local stability) and are supported with time series, phase portraits and bifurcation diagrams. Finally, numerical simulations are provided to demonstrate the theoretical findings.


1996 ◽  
Vol 1996 ◽  
pp. 174-174
Author(s):  
A.M. Sibbald

Voluntary food intake is generally inversely related to body condition or fatness in mature sheep (Foot, 1972). Since the intake of pelleted diets by housed sheep consists of a number of discrete feeding bouts or 'meals' (e.g. Bermudez et al., 1989), the relatively long-term effect of body condition on intake will be achieved through changes in feeding behaviour at the level of a single meal. The aim of this experiment was to compare the effects of body condition and short-term food restriction on meal patterns in sheep, to investigate the mechanism by which body condition influences daily food intake.


2020 ◽  
Vol 6 (49) ◽  
pp. eabd6370 ◽  
Author(s):  
Sen Pei ◽  
Sasikiran Kandula ◽  
Jeffrey Shaman

Assessing the effects of early nonpharmaceutical interventions on coronavirus disease 2019 (COVID-19) spread is crucial for understanding and planning future control measures to combat the pandemic. We use observations of reported infections and deaths, human mobility data, and a metapopulation transmission model to quantify changes in disease transmission rates in U.S. counties from 15 March to 3 May 2020. We find that marked, asynchronous reductions of the basic reproductive number occurred throughout the United States in association with social distancing and other control measures. Counterfactual simulations indicate that, had these same measures been implemented 1 to 2 weeks earlier, substantial cases and deaths could have been averted and that delayed responses to future increased incidence will facilitate a stronger rebound of infections and death. Our findings underscore the importance of early intervention and aggressive control in combatting the COVID-19 pandemic.


1998 ◽  
Vol 25 (6) ◽  
pp. 719 ◽  
Author(s):  
Jie Luo ◽  
Ji-Chu Chen ◽  
Yu-Ju Zhao

Cytokinins can cause de-etiolation of Arabidopsis thaliana (L.) Heynh. seedlings growing in the dark. Brassinosteroids (BRs) have been considered to regulate negatively the de-etiolation in dark-grown Arabidopsis seedlings. We show here that epi-brassinolide (epi-BL) can partially produce the phenotype of de-etiolation as caused by treatment with cytokinins in the dark, including the development of leaves and epicotyls in the wild-type and the BR-deficient mutant det2. But BRs cannot inhibit hypocotyl elongation, nor restore all the inhibition caused by cytokinins and light. We have found that there are distinct short term and long term phases of induction of de-etiolation by cytokinins. The short-term effect is probably coupled to ethylene in the inhibition of the hypocotyl elongation; the long-term effect causes morphogenesis of leaves and epicotyls. BRs can only regulate de-etiolation in the long term. We propose that the inhibition of hypocotyl elongation of det2 in darkness is caused by the absence of BR-dependent elongation rather than the inhibition caused by the expression of genes for photomorphogenesis. We propose that BRs resemble cytokinins in regulating de-etiolation as positive regulators, and that the inhibition of hypocotyl elongation and the development of leaves and epicotyls in de-etiolation are independent processes.


2019 ◽  
Vol 293 (1) ◽  
pp. 123-140
Author(s):  
Marco Gribaudo ◽  
Illés Horváth ◽  
Daniele Manini ◽  
Miklós Telek

Abstract The performance of service units may depend on various randomly changing environmental effects. It is quite often the case that these effects vary on different timescales. In this paper, we consider small and large scale (short and long term) service variability, where the short term variability affects the instantaneous service speed of the service unit and a modulating background Markov chain characterizes the long term effect. The main modelling challenge in this work is that the considered small and long term variation results in randomness along different axes: short term variability along the time axis and long term variability along the work axis. We present a simulation approach and an explicit analytic formula for the service time distribution in the double transform domain that allows for the efficient computation of service time moments. Finally, we compare the simulation results with analytic ones.


1985 ◽  
Vol 248 (6) ◽  
pp. E706-E711 ◽  
Author(s):  
J. P. van Putten ◽  
H. M. Krans

Catecholamines are known to have short-term regulatory effects on fat cell hexose uptake. We examined the long-term effects of catecholamines on the insulin-sensitive 2-deoxyglucose (dGlc) uptake in cultured 3T3-L1 adipocytes. Prolonged exposure (48 h) to isoproterenol (beta-adrenergic agonist) stimulated the basal dGlc uptake up to 90%. The effect was specific, time, concentration, and protein synthesis dependent and reversible. The effect of insulin was unaltered and superimposed on the increase in basal dGlc uptake. The long-term effect of isoproterenol was mimicked by epinephrine, dibutyryl cAMP (DBcAMP), and 1-methyl-3-isobutylxanthine (IBMX). By contrast, short-term exposure to isoproterenol (and epinephrine) induced a protein synthesis-independent increase in basal dGlc uptake (30%) not accompanied by an increase in insulin responsiveness. Moreover, on short-term basis, DBcAMP and IBMX suppressed both the basal and insulin-stimulated uptake up to 50%. Determination of the intracellular nonphosphorylated dGlc during the uptake and of the hexokinase activity revealed that the long-term effect of isoproterenol was most likely due to alterations low in dGlc transport. In conclusion, long-term regulators of hexose uptake are in cultured 3T3-L1 adipocytes, isoproterenol, and other cAMP stimulators. The long-term effect is independent from the short-term regulatory effect of the agents and from the effect of insulin.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Alexander F. Hagel ◽  
Heinz Albrecht ◽  
Andreas Nägel ◽  
Francesco Vitali ◽  
Marcel Vetter ◽  
...  

Introduction. Gastrointestinal bleeding represents the main indication for emergency endoscopy (EE). Lately, several hemostatic powders have been released to facilitate EE.Methods. We evaluated all EE in which Hemospray was used as primary or salvage therapy, with regard to short- and long-term hemostasis and complications.Results. We conducted 677 EE in 474 patients (488 examinations in 344 patients were upper GI endoscopies). Hemospray was applied during 35 examinations in 27 patients (19 males), 33 during upper and 2 during lower endoscopy. It was used after previous treatment in 21 examinations (60%) and in 14 (40%) as salvage therapy. Short-term success was reached in 34 of 35 applications (97.1%), while long-term success occurred in 23 applications (65.7%). Similar long-term results were found after primary application (64,3%) or salvage therapy (66,7%). Rebleeding was found in malignant and extended ulcers. One major adverse event (2.8%) occurred with gastric perforation after Hemospray application.Discussion. Hemospray achieved short-term hemostasis in virtually all cases. The long-term effect is mainly determined by the type of bleeding source, but not whether it was applied as first line or salvage therapy. But, even in the failures, patients had benefit from hemodynamic stabilization and consecutive interventions in optimized conditions.


Sign in / Sign up

Export Citation Format

Share Document