In the years 1999-2002, first studies were carried out on the metazoan parasites of Atlantic salmon (Salmo salar L.) recently reintroduced into the Elbe River drainage system, after more than 50 years after the complete extinction of the Elbe salmon population. A total of six helminth species were recorded from salmon smolts from three streams of the Elbe River basin (Kamenice River, Ještědský and Libočanský Brooks) in North Bohemia, Czech Republic, where S. salar fingerlings have been released since 1998: Gyrodactylus truttae Gläser, 1974, Crepidostomum metoecus Braun, 1900, Diplostomum spathaceum (Rudolphi, 1819) metacercariae, Raphidascaris acus (Bloch, 1799) adults and encapsulated larvae, Cystidicoloides ephemeridarum (Linstow, 1872), and Neoechinorhynchus rutili (Müller, 1780). Except for D. spathaceum, all these freshwater parasites have been received from the helminth fauna of the co-habiting brown trout (Salmo trutta fario L.). Due to local ecological conditions, the parasite faunae of both salmon and brown trout exhibited distinct qualitative and quantitative differences in the three localities. The finding of G. truttae on S. salar represents a new host record. Three helminth parasites of marine origin, the cestodes Eubothrium crassum (Bloch, 1779) and Scolex pleuronectis Müller, 1788 plerocercoids, and the nematode Anisakis simplex (Rudolphi, 1809) larvae were found in the single examined adult S. salar from the Kamenice River. New data on the geographical distribution of some nematode parasites of Salmo trutta fario L., Barbatula barbatula (L.) and Anguilla anguilla (L.) are presented.
Mitrostoma nototheniae Manter, 1954 is redescribed from Aplodactylus arctidens Richardson, off northern Tasmania. Opisthadena dimidia Linton, 1910 is reported from Kyphosus bigibbus Lacepède, Ningaloo, Western Australia, K. cinerascens (Forsskål), off Heron Island and Ningaloo, Western Australia, Kyphosus cornelii (Whitley), off Kalbarri, Western Australia, K. sydneyanus Günther, off Fremantle, Western Australia, K. sydneyanus ?, Ningaloo, Western Australia and K. vaigiensis (Quoy et Gaimard), off Heron and Lizard Islands, Queensland and Moorea, French Polynesia: measurements and an illustration are given. Neopisthadena habei Machida, 1980 is reported from K. sydneyanus off Fremantle, Western Australia: measurements and an illustration are given. Data derived from these specimens are used to recode a data-matrix developed by León-Règagnon et al. (1996), and the resultant tree produced is almost congruent with that of these authors. Our data indicate that this group of parasites is associated mostly with herbivorous hosts and that O. dimidia, while geographically widespread, is stenoxenic to the genus Kyphosus.
Ectoparasitic Prototransversotrema steeri Angel infected Acanthopagrus australis (Günther) in western (W. Bay) and southern (S. Bay) Moreton Bay with greatest abundance in winter (June - August), and none in summer (December - February). This confirms previous observations on seasonality of P. steeri from a small estuary in New South Wales. Transversotrema licinum Manter, which is a new host and geographical record, infects A. australis in W. Bay but not S. Bay, with large abundances in summer and winter, lowest abundance in spring. Increased size of P. steeri in winter in S. Bay could be explained by increased size offish sampled since fish length and size of each parasite species were correlated positively. Transversotrema licinum increased in size from summer to winter irrespective of fish size. Number of eggs in utero and parasite size were correlated for both species; worms in mid-size range had most eggs, and P. steeri had more eggs (average = 19.2, 0-80) than T. licinum (3.3, 0-21); eggs were similar in length. Number of eggs per parasite, adjusted for parasite size, was greatest in autumn (P. steeri) or summer (T. licinum), i.e. early in infection period. Spawning migration to eastern Moreton Bay did not influence number of eggs per parasite.
In this paper, we address the strong practical stabilization problem for a class of uncertain time delay systems with a nominal part written in triangular form. We propose, firstly, a strong practical observer. Then, we show that strong practical stability of the closed loop system with a linear, parameter dependent, state feedback is achieved. Finally, a separation principle is established, that is, we implement the control law with estimate states given by the strong practical observer and we prove that the closed loop system is strong practical stable. With the help of a numerical example, effectiveness of the proposed approach is demonstrated.
The problem of observer design for a class of nonlinear discrete-time systems with time-delay is considered. A new approach of nonlinear observer design is proposed for the class of systems. Based on differential mean value theory, the error dynamic is transformed into linear parameter variable system. By using Lyapunov stability theory and Schur complement lemma, the sufficient conditions expressed in terms of matrix inequalities are obtained to guarantee the observer error converges asymptotically to zero. Furthermore, the problem of observer design with affine gain is investigated. The computing method for observer gain matrix is given and it is also demonstrated that the observer error converges asymptotically to zero. Finally, an illustrative example is given to validate the effectiveness of the proposed method.
We address the secure control issue of networked non-affine nonlinear systems under denial of service (DoS) attacks. As for the situation that the system information cannot be measured in specific period due to the malicious DoS attacks, we design a neural networks (NNs) state observer with switching gain to estimate internal states in real time. Considering the error and dynamic performance of each subsystem, we introduce the recursive sliding mode dynamic surface method and a nonlinear gain function into the secure control strategy. The relationship between the frequency (duration) of DoS attacks and the stability of the system is established by the average dwell time (ADT) method. It is proven that the system can withstand the influence of DoS attacks and track the desired trajectory while preserving the boundedness of all closed-loop signals. Finally, simulation results are provided to verify the effectiveness of the proposed secure control strategy.
Při snižování a řízení hluku v komunálním prostředí je třeba rozlišovat dvě kategorie účinků hluku na člověka. Jsou to jednak přímé zdravotní účinky a jednak obecné obtěžování hlukem spadající do oblasti kvality života. Hluk z hlediska obou kategorií musí být v životním prostředí regulován – otázkou je nejvhodnější regulátor a odpovídající nejvhodnější nástroje. Stávající hluková legislativa administrovaná Ministerstvem zdravotnictví se týká ochrany veřejného zdraví, a nikoliv snižování hluku v životním prostředí jako celku. Řešení obecného obtěžování je věcí veřejného pořádku v kompetenci obcí, Městské policie a Policie České republiky. Nepochopení rozdílů obou přístupů vede často ke zbytečným nedorozuměním ze strany laické veřejnosti i médií, ale v řadě případů i veřejnosti odborné., In environmental noise management and regulation two categories of noise effects on humans should be taken into account: first by there are direct health effect and second by there is general noise annoyance belonging to the area of the quality of life. Noise, from the point of view of in both categories, should be regulated in the environment – the question is, however, the best proper authority and proper legislative tools for this regulation. Existing noise legislation within the agenda of the Ministry of Health concerns public health safety only and not the general reduction of all noise in the whole living environment. Solving the problem of general annoyance by noise is the a matter for the local authorities and the police. Lack of understanding of the difference of the two approaches often leads to unnecessary confusion in the lay public and the media, as well as in a number of cases among professionals., Tomáš Hellmuth, Dana Potužníková, Pavel Junek, Zdeněk Fiala, and Literatura