Lobster in a bottle: a novel technique for observing the predation of juvenile spiny lobster (Jasus edwardsii)

2016 ◽  
Vol 67 (11) ◽  
pp. 1625 ◽  
Author(s):  
Jan Hesse ◽  
Jenni A. Stanley ◽  
Andrew G. Jeffs

Determining the impact of predators on juvenile spiny lobsters living on reefs is important for understanding recruitment processes that ultimately help determine the size of economically important lobster populations. The present study describes a novel approach for observing attempted predation on live juvenile spiny lobster (Jasus edwardsii) in situ, by presenting the lobster in a transparent container that was lit with infrared light to enable continuous monitoring, even at night, by video recording. This technique can be used to provide valuable information on overall relative predation pressure from comparative locations and habitats, as well as identify potential predators, their mode of predation, and the timing of their of predation activity. For example, predation attempts on juvenile J. edwardsii by the spotted wrasse (Notolabrus celidotus) were recorded only from 0500 to 1400 hours (daytime) and from 1900 to 2100 hours (dusk), whereas the activity by the northern conger eel (Conger wilsoni) was observed only for the period between 2100 and 0200 hours (nocturnal). This method of assessing predation of juvenile lobsters provides considerable advantages over previously used tethering methods, by allowing continuous observations over a long time period (≥24h), including night time, while also eliminating experimental mortality of juvenile lobsters.

2017 ◽  
Vol 12 (1) ◽  
Author(s):  
Ulrik B. Pedersen ◽  
Dimitrios-Alexios Karagiannis-Voules ◽  
Nicholas Midzi ◽  
Tkafira Mduluza ◽  
Samson Mukaratirwa ◽  
...  

Temperature, precipitation and humidity are known to be important factors for the development of schistosome parasites as well as their intermediate snail hosts. Climate therefore plays an important role in determining the geographical distribution of schistosomiasis and it is expected that climate change will alter distribution and transmission patterns. Reliable predictions of distribution changes and likely transmission scenarios are key to efficient schistosomiasis intervention-planning. However, it is often difficult to assess the direction and magnitude of the impact on schistosomiasis induced by climate change, as well as the temporal transferability and predictive accuracy of the models, as prevalence data is often only available from one point in time. We evaluated potential climate-induced changes on the geographical distribution of schistosomiasis in Zimbabwe using prevalence data from two points in time, 29 years apart; to our knowledge, this is the first study investigating this over such a long time period. We applied historical weather data and matched prevalence data of two schistosome species (<em>Schistosoma haematobium</em> and <em>S. mansoni</em>). For each time period studied, a Bayesian geostatistical model was fitted to a range of climatic, environmental and other potential risk factors to identify significant predictors that could help us to obtain spatially explicit schistosomiasis risk estimates for Zimbabwe. The observed general downward trend in schistosomiasis prevalence for Zimbabwe from 1981 and the period preceding a survey and control campaign in 2010 parallels a shift towards a drier and warmer climate. However, a statistically significant relationship between climate change and the change in prevalence could not be established.


2021 ◽  
Vol 26 (40) ◽  
Author(s):  
Jessica E Stockdale ◽  
Renny Doig ◽  
Joosung Min ◽  
Nicola Mulberry ◽  
Liangliang Wang ◽  
...  

Background Many countries have implemented population-wide interventions to control COVID-19, with varying extent and success. Many jurisdictions have moved to relax measures, while others have intensified efforts to reduce transmission. Aim We aimed to determine the time frame between a population-level change in COVID-19 measures and its impact on the number of cases. Methods We examined how long it takes for there to be a substantial difference between the number of cases that occur following a change in COVID-19 physical distancing measures and those that would have occurred at baseline. We then examined how long it takes to observe this difference, given delays and noise in reported cases. We used a susceptible-exposed-infectious-removed (SEIR)-type model and publicly available data from British Columbia, Canada, collected between March and July 2020. Results It takes 10 days or more before we expect a substantial difference in the number of cases following a change in COVID-19 control measures, but 20–26 days to detect the impact of the change in reported data. The time frames are longer for smaller changes in control measures and are impacted by testing and reporting processes, with delays reaching ≥ 30 days. Conclusion The time until a change in control measures has an observed impact is longer than the mean incubation period of COVID-19 and the commonly used 14-day time period. Policymakers and practitioners should consider this when assessing the impact of policy changes. Rapid, consistent and real-time COVID-19 surveillance is important to minimise these time frames.


Author(s):  
Adarsh Anand ◽  
Navneet Bhatt ◽  
Deepti Aggrawal

A software system deals with various security implications after its release in the market. Correspondingly, firm releases security patches to counter those flaws discovered in the software system. A vendor releases a patch only if a vulnerability has been discovered in a software. It is an important aspect that encompasses the prediction of potential number of patches to be released to maintain the stability of a software. Vulnerability Discovery Models (VDMs) help a software vendor to acknowledge the security trends, forecast security investments and to plan patches, but very few attempts have been made to model the Vulnerability Patch Modeling (VPM) based on the impact of vulnerabilities discovered over the time period. In this proposal, we deduce a novel approach that addresses trend in the sequential development of patches based on the vendor or reporters fetching out the vulnerabilities in a software. The vulnerability trends in a software significantly affect the discovery process and later trigger a patch deployment to suppress the possible likelihood of a breach. The integrative approach underlines the association of vulnerability patch modeling with the vulnerability discovery phenomenon. To exemplify the proposed systematic structure, a statistical analysis has been conducted using real life vulnerability and patch datasets.


2020 ◽  
Author(s):  
Jessica E Stockdale ◽  
Renny Doig ◽  
Joosung Min ◽  
Nicola Mulberry ◽  
Liangliang Wang ◽  
...  

AbstractBackgroundMany countries have implemented population-wide interventions such as physical distancing measures, in efforts to control COVID-19. The extent and success of such measures has varied. Many jurisdictions with declines in reported COVID-19 cases are moving to relax measures, while others are continuing to intensify efforts to reduce transmission.AimWe aim to determine the time frame between a change in COVID-19 measures at the population level and the observable impact of such a change on cases.MethodsWe examine how long it takes for there to be a substantial difference between the cases that occur following a change in control measures and those that would have occurred at baseline. We then examine how long it takes to detect a difference, given delays and noise in reported cases. We use changes in population-level (e.g., distancing) control measures informed by data and estimates from British Columbia, Canada.ResultsWe find that the time frames are long: it takes three weeks or more before we might expect a substantial difference in cases given a change in population-level COVID-19 control, and it takes slightly longer to detect the impacts of the change. The time frames are shorter (11-15 days) for dramatic changes in control, and they are impacted by noise and delays in the testing and reporting process, with delays reaching up to 25-40 days.ConclusionThe time until a change in broad control measures has an observed impact is longer than is typically understood, and is longer than the mean incubation period (time between exposure than onset) and the often used 14 day time period. Policy makers and public health planners should consider this when assessing the impact of policy change, and efforts should be made to develop rapid, consistent real-time COVID-19 surveillance.


2015 ◽  
Vol 15 (17) ◽  
pp. 24727-24749 ◽  
Author(s):  
N. J. Harvey ◽  
H. F. Dacre

Abstract. The decision to close airspace in the event of a volcanic eruption is based on hazard maps of predicted ash extent. These are produced using output from volcanic ash transport and dispersion (VATD) models. In this paper an objective metric to evaluate the spatial accuracy of VATD simulations relative to satellite retrievals of volcanic ash is presented. The metric is based on the fractions skill score (FSS). This measure of skill provides more information than traditional point-by-point metrics, such as success index and Pearson correlation coefficient, as it takes into the account spatial scale over which skill is being assessed. The FSS determines the scale over which a simulation has skill and can differentiate between a "near miss" and a forecast that is badly misplaced. The idealised scenarios presented show that even simulations with considerable displacement errors have useful skill when evaluated over neighbourhood scales of 200–700 km2. This method could be used to compare forecasts produced by different VATDs or using different model parameters, assess the impact of assimilating satellite retrieved ash data and evaluate VATD forecasts over a long time period.


2012 ◽  
Vol 69 (5) ◽  
pp. 894-905 ◽  
Author(s):  
Debbie J. Freeman ◽  
Paul A. Breen ◽  
Alison B. MacDiarmid

The effects of fishing on growth in a spiny lobster, Jasus edwardsii , were explored by using a no-take marine reserve as a control for these effects. We analysed data from lobster tag–recapture studies outside the reserve from 1975 until the present and tag–recapture from inside the reserve during a recent 8-year study. We explored whether recent and historical data showed similar growth and, using catch per unit effort (CPUE) data from research potting and commercial returns, whether growth rates in this lobster species were affected by population density. Despite the confounded nature of the data, recent growth rates appeared to be lower than in earlier years, growth appeared weakly density-dependent, and the reserve appeared to have a positive effect on lobster growth. The strongest effect was the time period, but the density-dependent and reserve effects appeared real. The reserve effect suggests a negative effect of handling of sublegal-sized lobsters on growth.


2008 ◽  
Vol 59 (12) ◽  
pp. 1079 ◽  
Author(s):  
D. K. Bassett ◽  
A. G. Jeffs ◽  
J. C. Montgomery

Tethering prey is often used to help determine the impact of predators in aquatic communities. In this study, a novel photographic tethering device was used to make digital recordings of predation events on juveniles of the spiny lobster, Jasus edwardsii. Predation of lobsters was significantly higher during the day (76%) than at night (33.4%). This was consistent with a SCUBA survey that found greater numbers of diurnal predators than nocturnal predators at the study site. However, the abundance of predators was not consistent with the number of predation events for individual species as recorded by the photographic tethering device. The snapper, Pagrus auratus, was the most abundant species at the study site (45% of all diurnally active fishes), but was only responsible for 12% of predation events during the day. In contrast, wrasse species were responsible for the greatest number of predation events during the day (60%), yet made up only a small proportion of the diurnal fish population (25%). The results of this study indicate the importance of determining the identity of potential predators, through the use of a photographic tethering device, for increasing the value of results generated from tethering experiments.


2017 ◽  
Vol 125 (1-2) ◽  
pp. 146-156 ◽  
Author(s):  
Quinn P. Fitzgibbon ◽  
Ryan D. Day ◽  
Robert D. McCauley ◽  
Cedric J. Simon ◽  
Jayson M. Semmens

2016 ◽  
Vol 16 (2) ◽  
pp. 861-872 ◽  
Author(s):  
N. J. Harvey ◽  
H. F. Dacre

Abstract. The decision to close airspace in the event of a volcanic eruption is based on hazard maps of predicted ash extent. These are produced using output from volcanic ash transport and dispersion (VATD) models. In this paper the fractions skill score has been used for the first time to evaluate the spatial accuracy of VATD simulations relative to satellite retrievals of volcanic ash. This objective measure of skill provides more information than traditional point-by-point metrics, such as success index and Pearson correlation coefficient, as it takes into the account spatial scale over which skill is being assessed. The FSS determines the scale over which a simulation has skill and can differentiate between a "near miss" and a forecast that is badly misplaced. The idealized scenarios presented show that even simulations with considerable displacement errors have useful skill when evaluated over neighbourhood scales of 200–700 (km)2. This method could be used to compare forecasts produced by different VATDs or using different model parameters, assess the impact of assimilating satellite-retrieved ash data and evaluate VATD forecasts over a long time period.


2015 ◽  
Vol 54 (04) ◽  
pp. 359-363 ◽  
Author(s):  
N. Startsev ◽  
P. Dimov ◽  
B. Grosche ◽  
F. Tretyakov ◽  
J. Schüz ◽  
...  

Summary Background: To follow up populations exposed to several radiation accidents in the Southern Urals, a cause-of-death registry was established at the Urals Center capturing deaths in the Chelyabinsk, Kurgan and Sverdlovsk region since 1950. Objectives: When registering deaths over such a long time period, quality measures need to be in place to maintain quality and reduce the impact of individual coders as well as quality changes in death certificates. Methods: To ensure the uniformity of coding, a method for semi-automatic coding was developed, which is described here. Briefly, the method is based on a dynamic thesaurus, database-supported coding and parallel coding by two different individuals. Results: A comparison of the proposed method for organizing the coding process with the common procedure of coding showed good agreement, with, at the end of the coding process, 70 – 90% agreement for the three-digit ICD -9 rubrics. Conclusions: The semi-automatic method ensures a sufficiently high quality of coding by at the same time providing an opportunity to reduce the labor intensity inherent in the creation of large-volume cause-of-death registries.


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