20 research outputs found
Robust nonlinear controller based on set propagation
No full textBibliography: leaves 74-[76.]A novel control method, based on interval analysis, that optimises the control surface (or u-surface) for sampled systems with output disturbances is demonstrated on a driven pendulum with actuator constraints. The fitness function to be maximized is the probability of each state of the system being controlled to the setpoint without being perturbed to regions that are more iterations away from the setpoint. The u-surface is designed by finding all the states that could go to the setpoint in an interval and optimising these states. This process is repeated (backwards in time) by optimising states that go to the previously optimised states until no more states that have not been optimised are found. The proposed control method has been applied to the problem of swinging up a driven pendulum from rest to the inverted position with constraints on the torque of the motor. This method is computationally intensive and time constraints limit its current application to systems of low order
Theoretical mathematical model of fishery economics
No full textThe world population recently topped 6 billion people. Each person has the same need to eat, breathe, and drink. Unfortunately the world\u27s limited resources imply a carrying capacity for the human race. As we approach this critical mass, the strain on our resources becomes increasingly severe. We have already begun to realize such disasters. Many of the world\u27s fisheries have been destroyed, depleted to near nonexistence, or critically overfished. In some cases they only held on because the price of catching the final fish outweighed the potential revenue from catching it. This paper is an attempt to increase our understanding of the interaction between the economic motivations and biological forces at work in fisheries so that we may better preserve current stocks and help prevent future ecological devastation. More specifically, I seek to understand the decisions of fishermen in response to the price and stock of fish. The basis for my work is Backward Boycotts: Demand Management and Fishery Conservation , by J. Samuel Barkin and Kashif Mansori, who argue that the supply curve for a fishery may be downward sloping or be S-shaped
The image of Italian Mafia in Italian Cinematography
No full textThis paper shows the image of Mafia in Italian Cinematography. The author begins by presenting the origins of Mafia, who became a really powerful organization in the 19th century. In the second part, the author describes different forms of organized crime such as: Gomorra, Cosa Nostra, ‘Ndranghetta, taking into consideration their particular characteristics. In the last part, the focus is on various aspects of Mafia’s functioning as presented in Italian Cinematography, in selected films, which include: In nome della legge (1948, Pietro Germi), Cento Passi (2004, Marco TullioGiordana), Il giorno della civetta (1968, Damiano Damiani), Gomorra (2008, Matteo Garron
Isomer-Specific Hexabromocyclododecane (HBCDD) Levels in Top Predator Fish from Across Canada and 36-Year Temporal Trends in Lake Ontario
No full textHexabromocyclododecane (HBCDD) is
a high concern environmental
pollutant due to its persistent, bioaccumulative, and toxic properties.
The spatial distribution of HBCDD was investigated in top predator
fish (lake trout, walleye, or brook trout) collected in 2013 (n = 165) from 19 sampling sites and in 2015 (n = 145) from 20 sites across Canada. HBCDD was measurable in at least
one sample at each sampling site regardless of sampling year with
the exception of walleye from the south basin of Lake Winnipeg (2013).
Sampling sites in or near the Laurentian Great Lakes had greater ΣHBCDD
concentrations compared to locations to the west or east. The greatest
mean ΣHBCDD concentration was 72.6 ng/g lw in fish from Lake
Huron–Goderich (2015). Regardless of the sampling sites, α-HBCDD
was the dominant congener followed by γ-HBCDD, whereas β-HBCDD
was barely detectable. In fish from the same waterbody there were
comparable α/γ isomer concentration ratios. The greatest
ratio was 20.8 in fish from Lake Ontario, whereas the lowest ratio
was 6.3 for fish from Lac Memphrémagog (Québec) likely
related to more recent emissions of a technical HBCDD mixture. Temporal
trends of HBCDD in lake trout from Lake Ontario showed a significant
decreasing trend for γ-HBCDD with a half-life estimate of 10
years over a 36-year period (1979–2015), and for α-HBCDD
with a half-life of 11 years over the years of 2008 to 2015. The proportion
of α-HBCDD to ΣHBCDD increased significantly during 1979
to 2015. The present study provided novel information on the isomer-specific
HBCDDs in Canada freshwater fish
Isomer-Specific Hexabromocyclododecane (HBCDD) Levels in Top Predator Fish from Across Canada and 36-Year Temporal Trends in Lake Ontario
No full textHexabromocyclododecane (HBCDD) is
a high concern environmental
pollutant due to its persistent, bioaccumulative, and toxic properties.
The spatial distribution of HBCDD was investigated in top predator
fish (lake trout, walleye, or brook trout) collected in 2013 (n = 165) from 19 sampling sites and in 2015 (n = 145) from 20 sites across Canada. HBCDD was measurable in at least
one sample at each sampling site regardless of sampling year with
the exception of walleye from the south basin of Lake Winnipeg (2013).
Sampling sites in or near the Laurentian Great Lakes had greater ΣHBCDD
concentrations compared to locations to the west or east. The greatest
mean ΣHBCDD concentration was 72.6 ng/g lw in fish from Lake
Huron–Goderich (2015). Regardless of the sampling sites, α-HBCDD
was the dominant congener followed by γ-HBCDD, whereas β-HBCDD
was barely detectable. In fish from the same waterbody there were
comparable α/γ isomer concentration ratios. The greatest
ratio was 20.8 in fish from Lake Ontario, whereas the lowest ratio
was 6.3 for fish from Lac Memphrémagog (Québec) likely
related to more recent emissions of a technical HBCDD mixture. Temporal
trends of HBCDD in lake trout from Lake Ontario showed a significant
decreasing trend for γ-HBCDD with a half-life estimate of 10
years over a 36-year period (1979–2015), and for α-HBCDD
with a half-life of 11 years over the years of 2008 to 2015. The proportion
of α-HBCDD to ΣHBCDD increased significantly during 1979
to 2015. The present study provided novel information on the isomer-specific
HBCDDs in Canada freshwater fish
Isomer-Specific Hexabromocyclododecane (HBCDD) Levels in Top Predator Fish from Across Canada and 36-Year Temporal Trends in Lake Ontario
No full textHexabromocyclododecane (HBCDD) is
a high concern environmental
pollutant due to its persistent, bioaccumulative, and toxic properties.
The spatial distribution of HBCDD was investigated in top predator
fish (lake trout, walleye, or brook trout) collected in 2013 (n = 165) from 19 sampling sites and in 2015 (n = 145) from 20 sites across Canada. HBCDD was measurable in at least
one sample at each sampling site regardless of sampling year with
the exception of walleye from the south basin of Lake Winnipeg (2013).
Sampling sites in or near the Laurentian Great Lakes had greater ΣHBCDD
concentrations compared to locations to the west or east. The greatest
mean ΣHBCDD concentration was 72.6 ng/g lw in fish from Lake
Huron–Goderich (2015). Regardless of the sampling sites, α-HBCDD
was the dominant congener followed by γ-HBCDD, whereas β-HBCDD
was barely detectable. In fish from the same waterbody there were
comparable α/γ isomer concentration ratios. The greatest
ratio was 20.8 in fish from Lake Ontario, whereas the lowest ratio
was 6.3 for fish from Lac Memphrémagog (Québec) likely
related to more recent emissions of a technical HBCDD mixture. Temporal
trends of HBCDD in lake trout from Lake Ontario showed a significant
decreasing trend for γ-HBCDD with a half-life estimate of 10
years over a 36-year period (1979–2015), and for α-HBCDD
with a half-life of 11 years over the years of 2008 to 2015. The proportion
of α-HBCDD to ΣHBCDD increased significantly during 1979
to 2015. The present study provided novel information on the isomer-specific
HBCDDs in Canada freshwater fish
ENVIRONMENTAL CHEMISTRY, POLLUTION & WASTE MANAGEMENT | Analysis of benthic invertebrate communities downstream of land-based aquaculture facilities in ABOUT THE AUTHOR
No full textAbstract: Land-based aquaculture facilities are located throughout Nova Scotia. They are generally located beside streams, to which they discharge large quantities of used water, and their discharges are usually only monitored for some nutrient parameters at varying frequencies. However, intermittent water sampling is not sufficient to assess any aquatic ecosystem health impacts resulting from discharges. Monitoring benthic invertebrate populations' characteristics can be used to assess aquatic ecosystem health, and this study evaluated the benthic invertebrate population characteristics downstream of five land-based aquaculture facilities in Nova Scotia. Total abundance and relative abundance of Chironomidae were elevated, while number of taxa, relative abundance of Ephemeroptera + Plecoptera + Trichoptera (EPT), Pielou's evenness and diversity were reduced at three out of the five sampling locations. Furthermore, a comparison of populations of benthic invertebrates downstream of the facilities to those predicted by the Canadian Aquatic Biomonitoring Network Atlantic reference condition approach model revealed that population characteristics downstream at two out of the five facilities were noticeably different than those predicted by the model. Those population changes are consistent with other studies where nutrient enrichment was correlated to abundance and diversity
