Patterns of organic contaminants in marine mammals with reference to sperm whale strandings

Discriminant analysis has been applied to organochlorine contaminant data from a small number (ca 3-25) of 12 different marine mammal species to discriminate between the species on the basis of the chlorobiphenyls (CB) patterns in blubber and account for the effects of age, sex, condition and location of the mammals. The raw data are normalised to a single congener, CB 153, to reduce the effects of life history and sex, after which the discriminant factors are plotted to display the differences between species in relation to the intake and the metabolism of chlorobiphenyls. An understanding of these differences gives a better knowledge of the relative sensibility of these species. The sperm whales were found to have the least ability to metabolise CBs when compared with other cetaceans, although the concentration range observed for total CB was relatively low (265-6,313 µg/kg lipid weight)

Corrigendum to: Forensic delay analysis as evidence of transaction costs in construction projects.

This corrigendum contains several corrections to the text originally publishes at https://doi.org/10.1088/1755-1315/1101/5/052009

The Interpretation of Caribbean Paleogeography: Reply to Hedges

La hipòtesi de GMRlàndia (Iturralde-Vinent & MacPhee, 1999) especifica que una llengua de terra, capaç d'actuar com a via de dispersió per a organismes terrestres, va connectar les futures Antilles Majors amb la vorera del nord-oest de Sud Amèrica durant un període curt cap a la transició Eocè/Oligocè. Hedges (2001) ha criticat aquesta hipòtesi sota diferents prismes, i a aquest treball tractam de replicar algunes de les seves objeccions, tenint en compte l'evidència més recent que tenim sobre les següents tres qüestions: (1) Quant ha durat la presència dels ambients terrestres actuals de la conca del Carib? (2) Quines han estat les dates d'emergència més probables per a les illes que tenen aquests ambients? (3) Quin efecte tenen les corrents de superfície marines sobre la distribució dels objectes que suren a l'àrea del Carib? Primer, en contra del que diu Hedges, encara no hi ha evidència geològica per a donar suport a una continuïtat als ambients terrestres del Carib abans de fa 37 Ma. A llavors, la pretensió d'Hedges que com a mínim algunes entitats biòtiques haurien persistit in situ per períodes de més de 37 Ma (la data més primerenca suportada per tal evidència), com a minim a algunes de les illes actuals, encara no es pot mantenir sobre bases geològiques. Segon, l'esdeveniment d'importància decisiva en l'emergència de GMRlàndia no fou la baixada del nivell eustàtic de la mar, sinó l'aixecament d'lm arc insular tot seguint el final de la seva fase magmàtica. A llavors, notar, com Hedges fa, que l'emergència de GAARIàndia no va estar correlacionada amb una baixada identificable principal-encara que fos correcte- no és pertinent al problema plantejat. Ni ho són les incerteses de les datacions, tant de les baixades com de l' esdeveniment d'aixecament. Finalment, encara que el moviment de les corrents de superfície marines està afectat per la força de Coriolis, el vent és molt més important per al moviment dels objectes sobre la superfície. Experiments reals revelen que aquests moviments són significativament caòtics, cosa que condueix a que el transport passiu virtualment mai esdevindrà en línia recta. Com a resultat, encara que els objectes transportats pels rius de Sud Amèrica eventualment poden embarrancar a les costes del Carib, els temps de trànsit són probablement llargs. Aquest fet, tal volta més que qualsevol altre, condueix a que les llargues estades a la mar siguin un mètode improbable de dispersió exitosa per a moltes castes d'organismes. Òbviament, les investigacions geològiques i paleontològiques no poden falsar escenaris històrics, però poden subministrar termini ad qu.em per precisament el tipus d'esdeveniments en que els biogeògrafs insulars haurien d'estar interessats, tals com quan apareixen per primera vegada a una àrea ambients desitjables per organismes terrestres, i quins organismes (representats per les seves restes) eren els primers en disposar de l'avantatge d'aquestes noves terres.La hipòtesi de GMRlàndia (Iturralde-Vinent & MacPhee, 1999) especifica que una llengua de terra, capaç d'actuar com a via de dispersió per a organismes terrestres, va connectar les futures Antilles Majors amb la vorera del nord-oest de Sud Amèrica durant un període curt cap a la transició Eocè/Oligocè. Hedges (2001) ha criticat aquesta hipòtesi sota diferents prismes, i a aquest treball tractam de replicar algunes de les seves objeccions, tenint en compte l'evidència més recent que tenim sobre les següents tres qüestions: (1) Quant ha durat la presència dels ambients terrestres actuals de la conca del Carib? (2) Quines han estat les dates d' emergència més probables per a les illes que tenen aquests ambients? (3) Quin efecte tenen les corrents de superfície marines sobre la distribució dels objectes que suren a l'àrea del Carib? Primer, en contra del que diu Hedges, encara no hi ha evidència geològica per a donar suport a una continuïtat als ambients terrestres del Carib abans de fa 37 Ma. A llavors, la pretensió d'Hedges que com a mínim algunes entitats biòtiques haurien persistit in situ per períodes de més de 37 Ma (la data més primerenca suportada per tal evidència), com a minim a algunes de les illes actuals, encara no es pot mantenir sobre bases geològiques. Segon, l'esdeveniment d'importància decisiva en l'emergència de GMRlàndia no fou la baixada del nivell eustàtic de la mar, sinó l'aixecament d'lm arc insular tot seguint el final de la seva fase magmàtica. A llavors, notar, com Hedges fa, que l'emergència de GAARIàndia no va estar correlacionada amb una baixada identificable principal-encara que fos correcte- no és pertinent al problema plantejat. Ni ho són les incerteses de les datacions, tant de les baixades com de l' esdeveniment d'aixecament. Finalment, encara que el moviment de les corrents de superfície marines està afectat per la força de Coriolis, el vent és molt més important per al moviment dels objectes sobre la superfície. Experiments reals revelen que aquests moviments són significativament caòtics, cosa que condueix a que el transport passiu virtualment mai esdevindrà en línia recta. Com a resultat, encara que els objectes transportats pels rius de Sud Amèrica eventualment poden embarrancar a les costes del Carib, els temps de trànsit són probablement llargs. Aquest fet, tal volta més que qualsevol altre, condueix a que les llargues estades a la mar siguin un mètode improbable de dispersió exitosa per a moltes castes d'organismes. Òbviament, les investigacions geològiques i paleontològiques no poden falsar escenaris històrics, però poden subministrar termini ad quem per precisament el tipus d'esdeveniments en que els biogeògrafs insulars haurien d'estar interessats, tals com quan apareixen per primera vegada a una àrea ambients desitjables per organismes terrestres, i quins organismes (representats per les seves restes) eren els primers en disposar de l'avantatge d'aquestes noves terres.The GMRlandia hypothesis (Iturralde-Vinent & MacPhee, 1999) specifies that a landspan, capable of acting as a dispersal conduit for terrestrial organisms, connected the future Greater Antilles with the margin of northwestern South America for a short period around the time of the Eocene/Oligocene transition. Hedges (2001) has criticized this hypothesis on various grounds, and in this paper we seek to reply to several of his objections by considering the most recent evidence bearing on these three questions: (1) How long have the present land environments of the Caribbean basin been in existence? (2) What are the likeliest emergence dates for the islands supporting those environments? (3) What effect do sea-surface currents have on the distribution of flotsam in the Caribbean area? First, contra Hedges, there is still no geological evidence for continuity in Caribbean land envirorunents earlier than 37 Ma. Therefore, Hedges' claim that biotic entities on at least some of the present islands have persisted in situ for periods longer than 37 Ma (the earliest date supported by such evidence) still GUillot be sustained on geological grounds. Secondly, the event of overriding importance in the emergence of GMRlandia was not drawdown in eustatic sea level, but uplíft in the island arc following the termination of its magmatic phase. Therefore, noticing as Hedges does that the emergence of GMRlandia was not correlated with an identifiable major drawdown-even if correct-has no pertinence to the issue at hand. Neither do uncertainties in the dating of either drawdowns or the uplift event. Finally, although the movement of sea-surface currents is affected by the Coriolis force, wind is much more important for the motion of objects on the surface (flotsam). Actual experiments reveal that such motions are significantly chaotic, which means that passive transport will virtually never occur in a straight line. As a result, although objects carried by South American rivers may eventually wash up on Caribbean shores, transit times are likely to be long. This fact, perhaps more than any other, makes long seas journeys an improbable method of successful dispersal for many kinds of organisms. Among such organisms we count most land mammals, for a host of autecological and physiological reasons. For other kinds of organisms, including herps, different considerations may apply. Obviously, paleontological and geological investigations cannot falsify historical scenarios, but they can provide termini ad quem for precisely the kinds of events that island biogeographers should be interested in, such as when environments suitable for land organisms first appeared in an area, and what organisms (as represented by their remains) were the first to take advantage of these new lands.The GMRlandia hypothesis (Iturralde-Vinent & MacPhee, 1999) specifies that a landspan, capable of acting as a dispersal conduit for terrestrial organisms, connected the future Greater Antilles with the margin of northwestern South America for a short period around the time of the Eocene/Oligocene transition. Hedges (2001) has criticized this hypothesis on various grounds, and in this paper we seek to reply to several of his objections by considering the most recent evidence bearing on these three questions: (1) How long have the present land environments of the Caribbean basin been in existence? (2) What are the likeliest emergence dates for the islands supporting those environments? (3) What effect do sea-surface currents have on the distribution of flotsam in the Caribbean area? First, contra Hedges, there is still no geological evidence for continuity in Caribbean land envirorunents earlier than 37 Ma. Therefore, Hedges' claim that biotic entities on at least some of the present islands have persisted in situ for periods longer than 37 Ma (the earliest date supported by such evidence) still GUillot be sustained on geological grounds. Secondly, the event of overriding importance in the emergence of GMRlandia was not drawdown in eustatic sea level, but uplíft in the island arc following the termination of its magmatic phase. Therefore, noticing as Hedges does that the emergence of GMRlandia was not correlated with an identifiable major drawdown-even if correct-has no pertinence to the issue at hand. Neither do uncertainties in the dating of either drawdowns or the uplift event. Finally, although the movement of sea-surface currents is affected by the Coriolis force, wind is much more important for the motion of objects on the surface (flotsam). Actual experiments reveal that such motions are significantly chaotic, which means that passive transport will virtually never occur in a straight line. As a result, although objects carried by South American rivers may eventually wash up on Caribbean shores, transit times are likely to be long. This fact, perhaps more than any other, makes long seas journeys an improbable method of successful dispersal for many kinds of organisms. Among such organisms we count most land mammals, for a host of autecological and physiological reasons. For other kinds of organisms, including herps, different considerations may apply. Obviously, paleontological and geological investigations cannot falsify historical scenarios, but they can provide termini ad quem for precisely the kinds of events that island biogeographers should be interested in, such as when environments suitable for land organisms first appeared in an area, and what organisms (as represented by their remains) were the first to take advantage of these new lands

Integrating computer log files for process mining: a genetic algorithm inspired technique

Process mining techniques are applied to single computer log files. But many processes are supported by different software tools and are by consequence recorded into multiple log files. Therefore it would be interesting to find a way to automatically combine such a set of log files for one process. In this paper we describe a technique for merging log files based on a genetic algorithm. We show with a generated test case that this technique works and we give an extended overview of which research is needed to optimise and validate this technique

Prepyramid-to-pyramid transition of SiGe islands on Si(001)

The morphology of the first three-dimensional islands appearing during strained growth of SiGe alloys on Si(001) was investigated by scanning tunneling microscopy. High resolution images of individual islands and a statistical analysis of island shapes were used to reconstruct the evolution of the island shape as a function of size. As they grow, islands undergo a transition from completely unfacetted rough mounds (prepyramids) to partially {105} facetted islands and then they gradually evolve to {105} facetted pyramids. The results are in good agreement with the predictions of a recently proposed theoretical model

Radiocarbon Chronologies and Extinction Dynamics of the Late Quaternary Mammalian Megafauna of the Taimyr Peninsula, Russian Federation

This paper presents 75 new radiocarbon dates based on late Quaternary mammal remains recovered from eastern Taimyr Peninsula and adjacent parts of the northern Siberian lowlands, Russian Federation, including specimens of woolly mammoth (Mammuthus primigenius), steppe bison (Bison priscus), muskox (Ovibos moschatus), moose (Alces alces), reindeer (Rangifer tarandus), horse (Equus caballus) and wolf (Canis lupus). New evidence permits reanalysis of megafaunal extinction dynamics in the Asian high Arctic periphery. Increasingly, radiometric records of individual species show evidence of a gap at or near the Pleistocene/Holocene boundary (PHB). In the past, the PHB gap was regarded as significant only when actually terminal, i.e., when it marked the apparent ‘‘last’’ occurrence of a species (e.g., current ‘‘last’’ occurrence date for woolly mammoth in mainland Eurasia is 9600 yr BP). However, for high Arctic populations of horses and muskoxen the gap marks an interruption rather than extinction, because their radiocarbon records resume, nearly simultaneously, much later in the Holocene. Taphonomic effects, ΔC14 flux, and biased sampling are unlikely explanations for these hiatuses. A possible explanation is that the gap is the signature of an event, of unknown nature, that prompted the nearly simultaneous crash of many megafaunal populations in the high Arctic and possibly elsewhere in Eurasia.

Soft lepton-flavor violation in a multi-Higgs-doublet seesaw model

We consider the Standard Model with an arbitrary number n_H of Higgs doublets and enlarge the lepton sector by adding to each lepton family \ell a right-handed neutrino singlet \nu_{\ell R}. We assume that all Yukawa-coupling matrices are diagonal, but the Majorana mass matrix M_R of the right-handed neutrino singlets is an arbitrary symmetric matrix, thereby introducing an explicit but soft violation of all lepton numbers. We investigate lepton-flavor-violating processes within this model. We pay particular attention to the large-m_R behavior of the amplitudes for these processes, where m_R is the order of magnitude of the matrix elements of M_R. While the amplitudes for processes like tau^- --> mu^- gamma and Z --> tau^+ mu^- drop as 1/m_R^2 for arbitrary n_H, processes like tau^- --> mu^- e^+ e^- and mu^- --> e^- e^+ e^- obey this power law only for n_H = 1. For n_H \geq 2, on the contrary, those amplitudes do not fall off when m_R increases, rather they converge towards constants. This non-decoupling of the right-handed scale occurs because of the sub-process ell^- --> ell'^- {S_b^0}^*, where S_b^0 is a neutral scalar which subsequently decays to e^+ e^-. That sub-process has a contribution from charged-scalar exchange which, for n_H \geq 2, does not decrease when m_R tends to infinity. We also perform a general study of the non-decoupling and argue that, after performing the limit m_R --> \infty and removing the \nu_R from the Lagrangian, our model becomes a multi-Higgs-doublet Standard Model with suppressed flavor-changing Yukawa couplings. Finally, we show that, with the usual assumptions about the mass scales in the seesaw mechanism, the branching ratios of all lepton-flavor-changing processes are several orders of magnitude smaller than present experimental limits.Comment: 46 pages, 2 figures, Revte

Total Cross Section for p+p → p+p+pi0 Close to Threshold

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Scherk-Schwarz Supersymmetry Breaking for Quasi-localized Matter Fields and Supersymmetry Flavor Violation

We examine the soft supersymmetry breaking parameters induced by the Scherk-Schwarz (SS) boundary condition in 5-dimensional orbifold field theory in which the quark and lepton zero modes are quasi-localized at the orbifold fixed points to generate the hierarchical Yukawa couplings. In such theories, the radion corresponds to a flavon to generate the flavor hierarchy and at the same time plays the role of the messenger of supersymmetry breaking. As a consequence, the resulting soft scalar masses and trilinear $A$-parameters of matter zero modes at the compactification scale are highly flavor-dependent, thereby can lead to dangerous flavor violations at low energy scales. We analyze in detail the low energy flavor violations in SS-dominated supersymmetry breaking scenario under the assumption that the compactification scale is close to the grand unification scale and the 4-dimensional effective theory below the compactification scale is given by the minimal supersymmetric standard model. Our analysis can be applied to any supersymmetry breaking mechanism giving a sizable $F$-component of the radion superfield, e.g. the hidden gaugino condensation model.Comment: revtex4, 22 pages, some numerical errors are corrected in phenomenological analysis, main conclusion does not chang

PoLAR-FIT: Pliocene Landscapes and Arctic Remains—Frozen in Time

This short summary presents selected results of an ongoing investigation into the feedbacks that contribute to amplified Arctic warming. The consequences of warming for Arctic biodiversity and landscape response to global warmth are currently being interpreted. Arctic North American records of large-scale landscape and paleoenvironmental change during the Pliocene are exquisitely preserved and locked in permafrost, providing an opportunity for paleoenvironmental and faunal reconstruction with unprecedented quality and resolution. During a period of mean global temperatures only ~2.5°C above modern, the Pliocene molecular, isotopic, tree-ring, paleofaunal, and paleofloral records indicate that the high Arctic mean annual temperature was 11°C–19°C above modern values, pointing to a much shallower latitudinal temperature gradient than exists today. It appears that the intense Neogene warming caused thawing and weathering to liberate sediment and create a continuous and thick (>2.5 km in places) clastic wedge from at least Banks Island to Meighen Island to form a coastal plain that provided a highway for camels and other mammals to migrate and evolve in the high Arctic. In this summary we highlight the opportunities that exist for research on these and related topics with the PoLAR-FIT community.RÉSUMÉCe bref résumé présente les résultats choisis d'une enquête en cours sur les déclencheurs qui contribuent à l’amplification du réchauffement de l'Arctique. Les conséquences du réchauffement sur la biodiversité arctique et de la réponse du paysage au réchauffement climatique sont en cours d’être interprété. Des dossiers nord-américains de paysage à grande échelle et le changement paléoenvironnementales durant le Pliocène sont exceptionnellement préservés et scellées dans un état de congélation qui fournissant une occasion pour la reconstruction paléoenvironnementale et faunistique avec une qualité et une résolution sans précédent. Pendent une période de réchauffement global seulement ~2,5°C au-dessus de moderne les dossiers, moléculaire, isotopique, annaux de croissance, paléofaunistique et paléovégétation indiquent que l'Arctique a connu une augmentation de la température annuelle moyenne de 11°C–19°C au-dessus de moderne, en montrant un inferieur gradient de température latitudinal qu'aujourd'hui. Il semble que le réchauffement intense pendent le Néogène a provoqué la décongélation et erosion pour libérer les sédiments et créer une plaine côtière continuel et épaisse (> 2,5 km dans lieux) qui a fourni une route pour les chameaux et autres mammifères pour migrer et évoluer dans l’Haut-Arctique. Dans ce résumé, nous soulignons les opportunités qui existent pour la recherche sur ces sujets et les sujets connexes avec la communauté PoLAR-FIT