Estimating diet composition from scat analysis in otariid seals (Otariidae): is it reliable?

Analysis of teleost sagittal otoliths contained in scats has been widely used to determine the diet of seals. This method is based on the assumption that relative frequencies of otoliths in scats faithfully reflect those of fish in the diet. This assumption has rarely been tested experimentally. We compared the ratios of herring (Clupea harengus) to sprat (Sprattus sprattus) oto liths in faeces (output) of captive California sea lions (Zalophus calijornianus) and South American fur seals (Arctocephalus australis) with the ratios at feeding (input). Sea lions and fur seals showed no consistent differences in recovery rates and partial digestion of otoliths. Output ratios deviated only slightly from input ratios, the smaller sprat otoliths being underrepre sented in the output by 8%. Only about 40% of the otoliths fed to the seals were found in the scats. For both species partial digestion of otoliths led to a 16% underestimation of fish length and a 35% underestimation of fish mass.L'analyse des otolithes de tClCostCens contenus dans les fkces est une mCthode trks rCpandue de dktermination du rCgime alimentaire des phoques. Cette mCthode suppose que les frCquences relatives d'otolithes dans les fkces reflktent fidklement les frkquences relatives des poissons dans le rCgime. Cette prCmisse n'a pratiquement jamais fait l'objet de ~Crifications expkrimentales. Nous avons mesurC la proportion d'otolithes de harengs (Clupea harengus) et celle d'otolithes de sprats (Sprattus sprattus) dans les fkces (sortie) de Lions de mer californiens, Zalophus calijiornianus, et d'otaries a fourrure sud amkricaines, Arctocephalus australis, gardCs en captivitC, et comparC ces mesures aux proportions d'otolithes ingCrCs (entrCe). I1 n'y avait pas de diffkrence constante entre lions de mer et otaries et les taux de rCcupCration et de digestion partielle d'otolithes Ctaient les memes chez les deux espkces. Les proportions a la sortie diffkraient seulement un peu des proportions a I'entrCe et les otolithes des sprats, plus petits, Ctaient sous-reprCsentCs de 8% a la sortie. Seulement 40% environ des oto lithes ingCrCs ont CtC retrouvks a la sortie. La digestion partielle des otolithes chez les deux espkces entraine une sous-estima tion de la longueur des poissons consommCs, de I'ordre de 16%, et de la masse des poissons consommCs, de l'ordre de 35%.info:eu-repo/semantics/publishedVersio

Rethinking «Fuerza Mayor» in a World of Anthropogenic Climate Change

Este artículo aborda la pregunta sobre si los eventos de clima extremo deben servir de base para que los particulares o, incluso los Estados, puedan eximirse de cumplir con sus obligaciones legales.La antigua, pero aún muy viable, institución de la fuerza mayor, puede facultar tanto a las empresas como a los Estados-Nación a eximirse de sus responsabilidades y deberes. Sin embargo, en un mundo donde el cambio climático antropogénico está probado,¿podríamos decir que tales desastres son verdaderamente «naturales»? ¿Acaso tiene sentido, desde un punto de vista legal y fáctico, que se les siga permitiendo a las partes eximirse de responsabilidad legal cuando la ciencia moderna ha demostrado con toda probabilidad que, las personas -no algún misterioso poder universal- han ocasionado la mayoría de los problemas por los que buscamos eximirnos de responsabilidad?La fuerza mayor se basa en la idea de que el «hombre», de alguna manera, se encuentra separado de la «naturaleza». Este artículo cuestiona esta idea y argumenta que, en muchos casos, ya no tiene sentido aplicar la institución de la fuerza mayor. Al menos, los jueces deben ser muy cuidadosos al hacerlo por razones de política pública y asignación de riesgos, así como las partes contratantes deben tener la suficiente precaución al pensar o pretender que pueden ser capaces de eximirse de responsabilidad futura invocando cláusulas de «fuerza mayor».This article addresses the question of whether extreme weather events should form the basis for individuals or even the States, may be exempted from complying with its legal obligations.The old, but still very viable institution of force majeure can empower both companies and nations to absolve themselves of their responsibilities and duties. However, in a world where human-induced climate change is proven, could we say that such disasters are truly«natural»? Does it make sense, from a legal and factual matter, that they continue to allow the parties to be exempt from liability when modern science has shown that in all probability people, not some enigmatic power, have caused most universally of the problems that hold us harmless looking?Force majeure is based on the idea that the «man» somehow is separate from «nature». This article challenges this idea and argues that, in many cases, no longer makes sense to apply the institution of force majeure. At least, judges should be very careful in doing so for reasons of public policy and allocation of risks. In addition, the contracting parties must have enough caution to claim that they may be able to exempt themselves from future liability clauses appealing «force majeure»

Ethics roundtable: Using new, expensive drugs

Costly genetically engineered therapies, which threaten to cripple the health care industry economy and undermine the common good if applied indiscriminately, loom on the horizon. The spectrum of applicable candidates include moribund nursing home patients at the end of life. They will be fair game for therapy that will ultimately send them back to nursing homes to return later with the same condition. 'Quality of life' assessments that limit patient autonomy may be forced as a result. Discussants from South Africa, New Zealand, and the USA suggest methods to deal with this issue in a just and ethical framework

Ultrasensitive search for long-lived superheavy nuclides in the mass range A=288 to A=300 in natural Pt, Pb, and Bi

Theoretical models of superheavy elements (SHEs) predict a region of increased stability around the proton and neutron shell closures of Z = 114 and N = 184. Therefore a sensitive search for nuclides in the mass range from A = 288 to A = 300 was performed in natural platinum, lead, and bismuth, covering long-lived isotopes of Eka-Pt (Ds, Z = 110), Eka-Pb (Z = 114), and Eka-Bi (Z = 115). Measurements with accelerator mass spectrometry (AMS) at the Vienna Environmental Research Accelerator (VERA) established upper limits for these SHE isotopes in Pt, Pb, and Bi with abundances of <2×10-15, <5×10-14, and <5×10-13, respectively. These results complement earlier searches for SHEs with AMS at VERA in natural thorium and gold, which now amounts to a total number of 37 SHE nuclides having been explored with AMS. In none of our measurements was evidence found for the existence of SHEs in nature at the reported sensitivity level. Even though a few events were observed in the window for Ek293a-Bi, a particularly strong pileup background did not allow a definite SHE isotope identification. The present result sets limits on nuclides around the center of the island of stability, essentially ruling out the existence of SHE nuclides with half-lives longer than ∼150 million years

Upper limits for the existence of long-lived isotopes of roentgenium in natural gold

A sensitive search for isotopes of a superheavy element (SHE) in natural gold materials has been performed with accelerator mass spectrometry at the Vienna Environmental Research Accelerator, which is based on a 3-MV tandem accelerator. Because the most likely SHE in gold is roentgenium (Rg, Z=111), the search concentrated on Rg isotopes. Two different mass regions were explored: (i) For the neutron-deficient isotopes Rg261 and Rg265, abundance limits in gold of 3×10-16 were reached (no events observed). This is in stark contrast to the findings of Marinov, who reported positive identification of these isotopes with inductively coupled plasma sector field mass spectrometry in the (1-10)×10-10 abundance range. (ii) Theoretical models of SHEs predict a region of increased stability around the proton and neutron shell closures of Z = 114 and N = 184. We therefore investigated eight heavy Rg isotopes, ARg, A=289, 290, 291, 292, 293, 294, 295, and 296. For six isotopes no events were observed, setting limits also in the 10-16 abundance range. For Rg291 and Rg294 we observed two and nine events, respectively, which results in an abundance in the 10-15 range. However, pileup of a particularly strong background in these cases makes a positive identification as Rg isotopes-even after pileup correction-unlikely

Parametric study of prospective early commercial MHD power plants (PSPEC). General Electric Company, task 1: Parametric analysis

The performance and cost of moderate technology coal-fired open cycle MHD/steam power plant designs which can be expected to require a shorter development time and have a lower development cost than previously considered mature OCMHD/steam plants were determined. Three base cases were considered: an indirectly-fired high temperature air heater (HTAH) subsystem delivering air at 2700 F, fired by a state of the art atmospheric pressure gasifier, and the HTAH subsystem was deleted and oxygen enrichment was used to obtain requisite MHD combustion temperature. Coal pile to bus bar efficiencies in ease case 1 ranged from 41.4% to 42.9%, and cost of electricity (COE) was highest of the three base cases. For base case 2 the efficiency range was 42.0% to 45.6%, and COE was lowest. For base case 3 the efficiency range was 42.9% to 44.4%, and COE was intermediate. The best parametric cases in bases cases 2 and 3 are recommended for conceptual design. Eventual choice between these approaches is dependent on further evaluation of the tradeoffs among HTAH development risk, O2 plant integration, and further refinements of comparative costs