Impact of the California sea lion (Zalophus californianus) on salmon fisheries in Monterey Bay, California

To assess the impact of California sea lions (Zalophus californianus) on salmon fisheries in the Monterey Bay region of California, the percentages of hooked fish taken by sea lions in commercial and recreational salmon fisheries were estimated from 1997 to 1999. Onboard surveys of sea lion interactions with the commercial and recreational f isheries and dockside interviews with fishermen after their return to port were conducted in the ports of Santa Cruz, Moss Landing, and Monterey. Approximately 1745 hours of onboard and dockside surveys were conducted—924 hours in the commercial fishery and 821 hours in the recreational fishery (commercial passenger fishing vessels [CPFVs] and personal skiffs combined). Adult male California sea lions were responsible for 98.4% of the observed depredations of hooked salmon in the commercial and recreational fisheries in Monterey Bay. Mean annual percentages of hooked salmon taken by sea lions ranged from 8.5% to 28.6% in the commercial fishery, 2.2% to 18.36% in the CPFVs, and 4.0% to 17.5% in the personal skiff fishery. Depredation levels in the commercial and recreational salmon fisheries were greatest in 1998—likely a result of the large El Niño Southern Oscillation (ENSO) event that occurred from 1997 to 1998 that reduced natural prey resources. Commercial fishermen lost an estimated $18,031−$60,570 of gear and $225,833−$498,076 worth of salmon as a result of interactions with sea lions. Approximately 1.4−6.2% of the available salmon population was removed from the system as a result of sea lion interactions with the fishery. Assessing the impact of a growing sea lion population on fisheries stocks is difficult, but may be necessary for effective fisheries management

Food habits of California Sea Lions (Zalophus californianus) and their impact on Salmonid Fisheries in Monterey Bay, California

In the ocean commercial troll and recreational salmon fishery in Monterey Bay California, California sea lions (Zalophus califomianus) will swim near or follow fishing boats and will depredate fish once hooked. The objectives of the study were to determine the percentage of salmon taken by pinnipeds in commercial and recreational fisheries, identify relative importance of prey items seasonally consumed by sea lions, and determine the proportion of salmonids in the sea lion diet on a seasonal basis. From April 1997 through September 1998, 1041 hours of onboard and dockside surveys of the commercial and recreational salmon fisheries were conducted at the three ports in Monterey Bay, California. Sea lions depreadated 7.9 % of the fish hooked in the commercial fishery in 1997 and 28.6 % in 1998,8.4 % (1997) and 18.3 % (1998) of the CPFV fishery, and 15.6 % (1997) and 17.5 % (1998) of the private skiff fishery. Increased depredation rates in both the commercial and recreational salmon fisheries in 1998 were most likely the result of the large EI Nino Southern Oscillation event that occurred in 1997-1998 during which a greater number of sea lions were present in central California. Prey hardparts identified in sea lion fecal samples collected in Monterey Bay indicated that schooling fishes were the predominant prey fish species, such as market squid (Loligo opalescens), Pacific sardine (Sardinops caeruleus), northern anchovy (Engraulis mordax), and rockfish (Sebastes sp.). Sea lions consumed similar prey species in the summer and fall 1997, winter 1997-98, and spring 1998 (PSI> 70.0) with market squid and northern anchovy being the dominant prey species. However, prey composition changed significantly during the summer 1998 and fall 1998 (PSI < 46.0) because of the increased importance of sardine and rockfish in the diet and the decreased importance of market squid. This report does not intend to imply that salmonids are not a prey species for pinnipeds in the Monterey Bay region, but highlights the difficulties encountered in establishing the role of salmonids in the pinniped diet when analyzing fecal samples. (PDF contains 38 pages)

Magnetic trapping of buffer-gas cooled chromium atoms and prospects for the extension to paramagnetic molecules

We report the successful buffer-gas cooling and magnetic trapping of chromium atoms with densities exceeding $10^{12}$ atoms per cm$^{3}$ at a temperature of 350 mK for the trapped sample. The possibilities to extend the method to buffer-gas cool and magnetically trap molecules are discussed. To minimize the most important loss mechanism in magnetic trapping, molecules with a small spin-spin interaction and a large rotational constant are preferred. Both the CrH ($^6\Sigma^+$ ground state) and MnH ($^7\Sigma^+$) radicals appear to be suitable systems for future experiments.Comment: 9 pages, 4 Figure

Ein neues Verfahren zur Behandlung des fortgeschrittenen Lungenemphysems

Die Resultate der chirurgischen Lungenvolumenreduktion zeigen, daß Patienten länger überleben, wenn sie inhomogene, oberlappenbetonte Emphysemverteilung und eine niedrige funktionelle Reserve aufweisen. Die perioperativen Risiken und die Kosten des Verfahrens bleiben erheblich. Diverse endoskopische Verfahren der Lungenvolumenreduktion sind derzeit in klinischer Erprobung. Wir untersuchten die Machbarkeit und den funktionellen Benefit eines lobären Bronchusverschlusses durch segmental applizierte, silikonummantelte Nitinol-Bronchusverschlußblocker. Es wurden 20 Emphysempatienten nach Aufklärung und Einverständnis rekrutiert, die Kriterien für eine chirurgische Volumenreduktion erfüllten. Sie erhielten eine intensive Physiotherapie und eine optimale medikamentöse Therapie. Nach Implantation der Bronchusblocker durch flexible Bronchoskopie in Sedierung wurden die Patienten für 180 Tage funktionell, bildgebend und mittels Fragebögen nachuntersucht. Es verblieben N=10 Patienten bis zum d 180 der Studie. Die funktionellen Parameter der Überblähung (Δ Totale Lungenkapazität, TLC –4,5%, p=0,192, Δ Residualvolumen, RV –1,2%, p=0,75, n.s.) besserten sich. Ebenfalls besser fiel der St. George`s Respiratory Questionnaire (Δ –7,4%) und die forcierte Einsekundenkapazität (FEV1, Δ+ 4,6%) aus. Die Differenzierung nach Atelektase oder deren Ausbleiben ergibt bessere Resultate für Patienten mit Atelektase, und zwar Δ FEV1+10,7% mit vs. Δ FEV1-1,4% ohne Atelektase (p=0,346), ΔTLC –8,4% mit vs. ΔTLC –0,5% ohne Atelektase (p= 0,172) und ΔRV –13,5% mit vs. Δ RV +11,2% ohne Atelektase (p= 0,081) sowie Δ-20,7% im SGRQ mit vs. Δ44,1% ohne Atelektase (p=0,0205). In der Ergometrie erzielten Patienten mit Atelektase eine Leistung in Watt von Δ+ 8,3% gegenüber einem Δ- 11.1% ohne Atelektase (p= 0,411, n. s.). Die Daten zeigen zu früheren Kontrollpunkten (30, 60, 90d) größere Differenzen zugunsten der Atelektasen-Gruppe. Dies weist auf einen schwindenden Benefit hin, der mit Re-Ventilation durch unvollständigen Verschluß erklärt werden kann. Komplikationen traten in Form von Pneumothorax (N=2) und Pneumonien (N=3, davon 1†) bzw. broncho-pulmonalen Infekten (N=7) auf. Die endoskopische Volumenreduktion mit Bronchusblockern ist ein reversibles, ausreichend sicheres und praktikables Verfahren, deren Vorteil gegenüber der operativ -resezierenden Methode aktuell noch nicht belegbar ist

Phosphate and plaster bonded syntactic foams for collapsible cores in light metal casting

In the casting industry so called “lost cores” are used to fabricate cavities in casted components. Those cores are typically made from inorganic materials like sand and have to satisfy a variety of requirements – some of which are contradictory. Among others, they have to be stable against the thermal and mechanical loads of the casting process; they must not be infiltrated by the metal melt or induce chemical reactions detrimental to the performance of the casting. Last but not least demolding has to be easy, i.e. the core has to be destroyed and removed from the casting very easily and without any residues. Especially for small and delicate cores these requirements are very difficult to meet. Please click Additional Files below to see the full abstract

Fractional-Order Partial Cancellation of Integer-Order Poles and Zeros

The key idea of this contribution is the partial compensation of non-minimum phase zeros or unstable poles. Therefore the integer-order zero/pole is split into a product of fractional-order pseudo zeros/poles. The amplitude and phase response of these fractional-order terms is derived to include these compensators into the loop-shaping design. Such compensators can be generalized to conjugate complex zeros/poles, and also implicit fractional-order terms can be applied. In the case of the non-minimum phase zero, its compensation leads to a higher phase margin and a steeper open-loop amplitude response around the crossover frequency resulting in a reduced undershooting in the step-response, as illustrated in the numerical example.publishedVersio