Cross-amplification of polymorphic microsatellites reveals extra-pair paternity and brood parasitism in Sturnus vulgaris

We tested the cross-amplification of 37 microsatellites in a population of starlings (Stumus vulgaris). Twenty-three of them amplified and five exhibited a large number of alleles per locus and high heterozygosity (on average: 14.6 alleles/locus and H. = 0.704). We assessed the occurrence of extra-pair paternity (EPP) and intraspecific brood parasitism GBP) in this population. The EPP rate was 16% to 18% offspring from 43% to 45% of nests. IBP was very variable between two successive years (14% to 27% chicks from 25% to 64% of clutches). These five polymorphic markers will be of potential use in studies of genetic diversity, population structure and reproductive strategy of this species.

A Rotating black ring solution in five dimensions

The vacuum Einstein equations in five dimensions are shown to admit a solution describing a stationary asymptotically flat spacetime regular on and outside an event horizon of topology S1S2. It describes a rotating black ring. This is the first example of a stationary asymptotically flat vacuum solution with an event horizon of nonspherical topology. The existence of this solution implies that the uniqueness theorems valid in four dimensions do not have simple five-dimensional generalizations. It is suggested that increasing the spin of a spherical black hole beyond a critical value results in a transition to a black ring, which can have an arbitrarily large angular momentum for a given mass.

Large D gravity and low D strings

We show that in the limit of a large number of dimensions a wide class of nonextremal neutral black holes has a universal near-horizon limit. The limiting geometry is the two-dimensional black hole of string theory with a two-dimensional target space. Its conformal symmetry explains the properties of massless scalars found recently in the large-D limit. For black branes with string charges, the near-horizon geometry is that of the three-dimensional black strings of Horne and Horowitz. The analogies between the α′ expansion in string theory and the large-D expansion in gravity suggest a possible effective string description of the large-D limit of black holes. We comment on applications to several subjects, in particular to the problem of critical collapse.

Yverdon-les-Bains et Sermuz à la fin de l'âge du fer

La première partie de cette étude est consacrée à l'étude des vestiges découverts entre 1990 et 1994 à Yverdon-les-Bains (VD) en quatre points de la rue des Philosophes (n°s 7, 13, 21 et 27). L'étude des secteurs fouillés permet de retracer l'histoire d'une zone périphérique de l'agglomération depuis la fin du IVe s. av. J.-C. jusqu'au haut Moyen Age, où une nécropole s'est développée sur trois des parcelles étudiées {cf. CAR 75). L'accès oriental de l'agglomération est barré dès la fin du IVe s. par une palissade peut-être associée à un fossé. Le secteur sud n'a pas livré de vestige contemporain de cet aménagement, mais a été fréquenté depuis le début du IIe s. av. notre ère. Par la suite, un réseau de fossés de petites dimensions a été mis en place, qui d'un point de vue topographique se situe en aval du cordon littoral III, dans une zone anciennement marécageuse. Une fonction drainante a ainsi été postulée pour ces aménagements, qui ont peut-être été réalisés en vue de la construction du rempart. Celui-ci a été dégagé sur trois des parcelles fouillées. Un niveau de démolition repéré au n° 7 de la rue des Philosophes indique qu'il se prolongeait probablement en direction du lac, de l'autre côté de la voie d'accès conduisant à Voppidum partiellement dégagée en 1982 .Le rempart d'Yverdon se rattache au groupe des remparts à poteaux frontaux (Pfostenschlitzmauer) caractérisé par un parement en pierres sèches interrompu à intervalles réguliers (en moyenne 1.40 m) par des pieux de grandes dimensions (section: 50/60 x 30/40 cm) qui étaient reliés à une seconde rangée de pieux, distante d'environ 4 m du front de l'ouvrage; une rampe située à l'arrière de ce dispositif devait assurer la stabilité de l'ensemble. L'excellente conservation de plusieurs dizaines de ces pieux a permis de dater de manière absolue la construction de l'ouvrage vers 80 av. J.-C. Le rempart yverdonnois présente une particularité technique inédite des plus intéressante du point de vue constructif : les pieux des deux rangées ne sont pas implantés verticalement comme cela est généralement le cas, mais de manière oblique. Ce mode opératoire présente un progrès important, car il améliore notablement le comportement statique de l'ouvrage tout en facilitant sa mise en oeuvre (étude du Prof. L. Pflug). La fortification est précédée, dans le secteur sud, par plusieurs aménagements en bois, dont une palissade construite quelques années avant le rempart lui-même et une série de pieux qui pourrait appartenir à une ligne de défense avancée. Trois fossés précèdent le rempart dans le secteur oriental. Le premier, situé à moins d'un mètre de la base de la fortification, est probablement antérieur à cette dernière. Hormis les structures à caractère défensif, plusieurs aménagements de La Tène finale ont été dégagés sur les différentes parcelles, dont une cabane semi-enterrée de plan rectangulaire au n° 7 de la rue des Philosophes. En raison de sa situation extra muros et de son plan, une vocation artisanale a été proposée pour ce bâtiment. Une tombe datée de La Tène D1 par ses offrandes a été découverte au nord du chantier des Philosophes 21 parmi un groupe de sépultures de la nécropole tardo-antique du Pré de la Cure. La transgression lacustre mise en évidence au Parc Piguet paraît également avoir affecté la partie orientale de l'oppidum. Cet événement est survenu avant la démolition de la fortification, qui est datée vers le milieu du Ier s. avant notre ère. Les vestiges du vicus d'époque romaine, dégagés uniquement sur de petites surfaces, comprennent plusieurs constructions en terre et bois, une cave et un bâtiment maçonnés ainsi que plusieurs puits. L'étude du mobilier associé aux aménagements les plus récents situe l'abandon de l'agglomération dans la seconde moitié du IIIe s. ap. J.-C. pour trois des parcelles fouillées, alors que la zone des Philosophes 27 était peut-être encore occupée au siècle suivant.Les fouilles ont livré un abondant mobilier dont la majeure partie remonte à La Tène finale. La céramique de cette époque a été classée en fonction de critères technologique, formel et esthétique précis afin de mettre en évidence des marqueurs significatifs en termes chronologiques. Six horizons principaux ont été distingués, qui s'échelonnent entre le IIe s. av. J.-C. et le début de l'époque tibérienne. On retiendra pour la fin de l'âge du Fer que la première partie de La Tène finale est caractérisée par un vaisselier comprenant une majorité de formes basses en pâte sombre fine, alors que la période suivante voit une nette augmentation des récipients en pâte grossière, dont la plupart sont des pots à cuire à large lèvre déversée. Le registre décoratif évolue également: certains motifs ne sont attestés que durant une période, alors que d'autres se distinguent uniquement par leur fréquence. D'un point de vue économique, Yverdon, à l'image des sites du Plateau suisse, se situe durant la première partie de La Tène finale en dehors des voies commerciales. Les produits méditerranéens sont en effet extrêmement rares durant cette période, alors que leur nombre augmente sensiblement vers la fin de l'âge du Fer. La seconde partie de cette étude est dévolue à l'étude du murus gallicus de Sermuz (Ph. Curdy) et à la comparaison des divers modes constructifs mis en oeuvre pour les fortifications de la région des Trois-Lacs. La partie conclusive récapitule de manière chronologique l'évolution des occupations à Yverdon-les-Bains depuis l'âge du Bronze jusqu'au haut Moyen Âge et propose d'intégrer les nouveaux résultats dans une perspective historique. Diverses hypothèses évoquent les raisons qui conduirent les Yverdonnois à se retrancher vers 80 av. J.-C. et les relations qu'ils entretenaient avec le site voisin de Sermuz. Pour terminer, la fonction de ce dernier est discutée dans ce cadre, notamment l'hypothèse d'une occupation du territoire helvète par des troupes romaines antérieure à l'Alpenfeldzug .

Large N QCD from rotating branes

We study large N SU(N) Yang-Mills theory in three and four dimensions using a one-parameter family of supergravity models which originate from non-extremal rotating D-branes. We show explicitly that varying this angular momentum parameter decouples the Kaluza-Klein modes associated with the compact D-brane coordinate, while the mass ratios for ordinary glueballs are quite stable against this variation, and are in good agreement with the latest lattice results. We also compute the topological susceptibility and the gluon condensate as a function of the "angular momentum" parameter.

Extra Forces induced by wide-pulse, high-frequency electrical stimulation: Occurrence, magnitude, variability and underlying mechanisms.

OBJECTIVE: In contrast to conventional (CONV) neuromuscular electrical stimulation (NMES), the use of "wide-pulse, high-frequencies" (WPHF) can generate higher forces than expected by the direct activation of motor axons alone. We aimed at investigating the occurrence, magnitude, variability and underlying neuromuscular mechanisms of these "Extra Forces" (EF). METHODS: Electrically-evoked isometric plantar flexion force was recorded in 42 healthy subjects. Additionally, twitch potentiation, H-reflex and M-wave responses were assessed in 13 participants. CONV (25Hz, 0.05ms) and WPHF (100Hz, 1ms) NMES consisted of five stimulation trains (20s on-90s off). RESULTS: K-means clustering analysis disclosed a responder rate of almost 60%. Within this group of responders, force significantly increased from 4% to 16% of the maximal voluntary contraction force and H-reflexes were depressed after WPHF NMES. In contrast, non-responders showed neither EF nor H-reflex depression. Twitch potentiation and resting EMG data were similar between groups. Interestingly, a large inter- and intrasubject variability of EF was observed. CONCLUSION: The responder percentage was overestimated in previous studies. SIGNIFICANCE: This study proposes a novel methodological framework for unraveling the neurophysiological mechanisms involved in EF and provides further evidence for a central contribution to EF in responders.

Abnormal Returns of Dividend Announcements during a Boom and a Recession. Empirical Evidence from U.S. from the years of 2000 - 2002 and 2005 - 2007, including Finnish Extra Dividends

This study examines the short time price effect of dividend announcements during a boom and a recession. The data being used here is gathered from the years of 2000 - 2002 when it was a recession after the techno bubble burst and from the years 2005 - 2007 when investors experienced large capital gains all around the world. The data consists of dividend increases and intact observations. The aim is to find out differences in abnormal returns between a boom and a recession. Second, the study examines differences between different dividend yield brackets. Third, Finnish extra dividends, mainly being delivered to shareholders in 2004 are included to the empirical test. Generally stated, the aim is to find out do investors respect dividends more during a recession than a boom and can this be proved by using dividend yield brackets. The empirical results from U.S shows that the abnormal returns of dividend increase announcements during the recession in the beginning of this decade were larger than during the boom. Thus, investors seem to respect dividend increases more when stock prices are falling. Substantial abnormal returns of dividend increases during the time period of 2005 - 2007 could not be found. The results from the overall samples state that the abnormal returns during the recession were positively slightly higher than during the boom. No clear and strong evidence was found between different dividend yield brackets. In Finland, there were substantial abnormal returns on the announcement day of the extra dividends. Thus, indicating that investors saw the extra dividends as a good thing for shareholders' value. This paper is mostly in line with the theory that investors respect dividends more during bad times than good times.

Abnormal Return of Dividend Announcements during a Boom and a Recession. Empirical evidence from the years of 2002 - 2002 and 2005 - 2007, including the Finnish extra dividends

Tutkimuksen tavoitteena on tutkia epänormaalien tuottojen esiintymistä nousu- ja laskusuhdanteen aikana osingonilmoituspäivän ympärillä. Osinkoilmoitukset ovat kerätty Yhdysvaltojen markkinalta (NYSE) ajanjaksoilta 2000 - 2002, jolloin pörssit laskivat teknokuplan jälkeen ja 2005 - 2007, jolloin sijoittajat kokivat suuria kurssivoittoja. Osinkoilmoitushavainnot koostuvat yhtiöistä, jotka nostivat tai pitivät osinko per osake paikallaan. Tavoitteena on tutkia eroja epänormaaleissa tuotoissa näiden kahden ajanjakson välillä. Toiseksi, tavoitteena on tutkia miten epänormaalit tuotot poikkeavat toisistaan eri osinkotuottoluokissa. Kolmanneksi, tavoitteena on tutkia esiintyikö markkinoilla epänormaaleja tuottoja kun suomalaiset yritykset ilmoittivat ylimääräisistä osingoista, pääasiassa vuonna 2004. Yksinkertaisesti ja lyhyesti sanottuna tavoitteena on tutkia arvostavatko sijoittajat osinkoja enemmän laskukauden vai nousukauden aikana. Rahoitusteorian mukaan sijoittajien tulisi arvostaa laskukauden aikana enemmän yhtiöitä, jotka pystyvät maksamaan huonosta taloustilanteesta huolimatta hyvää osinkoa. Empiiriset testit Yhdysvalloista osoittavat, että osingon nostamisesta johtuvat epänormaalit tuotot olivat suuremmat laskusuhdanteen aikana kuin noususuhdanteen aikana. Tämä on linjassa teorian kanssa. Osingon-nostot aiheuttivat nousukauden aikana vähäisiä epänormaaleja tuottoja. Selviä eroja eri osingontuottoluokkien välillä ei pystytty havaitsemaan. Tulokset yhdistetystä aineistosta osoittavat, että sijoittajat kokivat vähäisiä positiivisia epänormaaleja tuottoja laskukauden aikana. Nousukautena tuotot olivat lähellä nollaa. Suomen markkinoilla havaittiin selvä epänormaalituotto osingonilmoituspäivänä. Tulokset ovat pääpiirteittäin linjassa teorian kanssa. Sijoittajat arvostavat osinkoja hieman enemmän lasku- kuin noususuhdanteen aikana.

Recovery and refining of manganese as by-product from hydrometallurgical processes

The consumption of manganese is increasing, but huge amounts of manganese still end up in waste in hydrometallurgical processes. The recovery of manganese from multi-metal solutions at low concentrations may not be economical. In addition, poor iron control typically prevents the production of high purity manganese. Separation of iron from manganese can be done with chemical precipitation or solvent extraction methods. Combined carbonate precipitation with air oxidation is a feasible method to separate iron and manganese due to the fast kinetics, good controllability and economical reagents. In addition the leaching of manganese carbonate is easier and less acid consuming than that of hydroxide or sulfide precipitates. Selective iron removal with great efficiency from MnSO4 solution is achieved by combined oxygen or air oxidation and CaCO3 precipitation at pH > 5.8 and at a redox potential of > 200 mV. In order to avoid gypsum formation, soda ash should be used instead of limestone. In such case, however, extra attention needs to be paid on the reagents mole ratios in order to avoid manganese coprecipitation. After iron removal, pure MnSO4 solution was obtained by solvent extraction using organophosphorus reagents, di-(2-ethylhexyl)phosphoric acid (D2EHPA) and bis(2,4,4- trimethylpentyl)phosphinic acid (CYANEX 272). The Mn/Ca and Mn/Mg selectivities can be increased by decreasing the temperature from the commonly used temperatures (40 –60oC) to 5oC. The extraction order of D2EHPA (Ca before Mn) at low temperature remains unchanged but the lowering of temperature causes an increase in viscosity and slower phase separation. Of these regents, CYANEX 272 is selective for Mn over Ca and, therefore, it would be the better choice if there is Ca present in solution. A three-stage Mn extraction followed by a two-stage scrubbing and two-stage sulfuric acid stripping is an effective method of producing a very pure MnSO4 intermediate solution for further processing. From the intermediate MnSO4 some special Mn- products for ion exchange applications were synthesized and studied. Three types of octahedrally coordinated manganese oxide materials as an alternative final product for manganese were chosen for synthesis: layer structured Nabirnessite, tunnel structured Mg-todorokite and K-kryptomelane. As an alternative source of pure MnSO4 intermediate, kryptomelane was synthesized by using a synthetic hydrometallurgical tailings. The results show that the studied OMS materials adsorb selectively Cu, Ni, Cd and K in the presence of Ca and Mg. It was also found that the exchange rates were reasonably high due to the small particle dimensions. Materials are stable in the studied conditions and their maximum Cu uptake capacity was 1.3 mmol/g. Competitive uptake of metals and acid was studied using equilibrium, batch kinetic and fixed-bed measurements. The experimental data was correlated with a dynamic model, which also accounts for the dissolution of the framework manganese. Manganese oxide micro-crystals were also bound onto silica to prepare a composite material having a particle size large enough to be used in column separation experiments. The MnOx/SiO2 ratio was found to affect significantly the properties of the composite. The higher the ratio, the lower is the specific surface area, the pore volume and the pore size. On the other hand, higher amount of silica binder gives composites better mechanical properties. Birnesite and todorokite can be aggregated successfully with colloidal silica at pH 4 and with MnO2/SiO2 weight ratio of 0.7. The best gelation and drying temperature was 110oC and sufficiently strong composites were obtained by additional heat-treatment at 250oC for 2 h. The results show that silica–supported MnO2 materials can be utilized to separate copper from nickel and cadmium. The behavior of the composites can be explained reasonably well with the presented model and the parameters estimated from the data of the unsupported oxides. The metal uptake capacities of the prepared materials were quite small. For example, the final copper loading was 0.14 mmol/gMnO2. According to the results the special MnO2 materials are potential for a specific environmental application to uptake harmful metal ions.

Ethnic conflicts and international politics : an analysis of the communal regional, and global dimensions of the Cyprus problem

The thesis assesses the impact of international factors on relations between Greek and Turkish Cypriots during and after the Cold War. Through an analysis of the Cyprus problem it explores both why external actors intervene in communal conflicts and how they influence relations between ethnic groups in plural societies. The analytical framework employed throughout the study draws on contributions of International Relations theorists and students of ethnic conflict. The thesis argues that, as in the global political system, relations between ethnic groups in unranked communal systems are anarchic; that is, actors within the system do not recognize a sovereign political authority. In bipolar communal systems dominated by two relatively equal groups, the struggle for security and power often leads to appeals for assistance from external actors. The framework notes that neighboring states and Great Powers may heed calls for assistance, or intervene without a prior request, if it is in their interest to do so. The convergence of regional and global interests in communal affairs exacerbates ethnic conflicts and precludes the development of effective political institutions. The impact of external intervention in ethnic conflicts has the potential to alter the basis of communal relations. The Cyprus problem is examined both during and after the Cold War in order to gauge how global and regional actors and the structure of their respective systems have affected relations between ethnic groups in Cyprus. The thesis argues that Cyprus's descent into civil war in 1963 was due in part to the entrenchment of external interests in the Republic's constitution. The study also notes that power politics involving the United States, Soviet Union, Greece and Turkey continued to affect the development of communal relations throughout the 1960s, 70s, and, 80s. External intervention culminated in July and August 1974, after a Greek sponsored coup was answered by Turkey's invasion and partition of Cyprus. The forced expulsion of Greek Cypriots from the island's northern territories led to the establishment of ethnically homogeneous zones, thus altering the context of communal relations dramatically. The study also examines the role of the United Nations in Cyprus, noting that its failure to settle the dispute was due in large part to a lack of cooperation from Turkey, and the United States' and Soviet Union's acceptance of the status quo following the 1974 invasion and partition of the island. The thesis argues that the deterioration of Greek-Turkish relations in the post-Cold War era has made a solution to the dispute unlikely for the time being. Barring any dramatic changes in relations between communal and regional antagonists, relations between Greek and Turkish Cypriots will continue to develop along the lines established in July/August 1974. The thesis concludes by affirming the validity of its core hypotheses through a brief survey of recent works touching on international politics and ethnic conflict. Questions requiring further research are noted as are elements of the study that require further refinement.

Group-invariant solutions of semilinear Schrodinger equations in multi-dimensions

Symmetry group methods are applied to obtain all explicit group-invariant radial solutions to a class of semilinear Schr¨odinger equations in dimensions n = 1. Both focusing and defocusing cases of a power nonlinearity are considered, including the special case of the pseudo-conformal power p = 4/n relevant for critical dynamics. The methods involve, first, reduction of the Schr¨odinger equations to group-invariant semilinear complex 2nd order ordinary differential equations (ODEs) with respect to an optimal set of one-dimensional point symmetry groups, and second, use of inherited symmetries, hidden symmetries, and conditional symmetries to solve each ODE by quadratures. Through Noether’s theorem, all conservation laws arising from these point symmetry groups are listed. Some group-invariant solutions are found to exist for values of n other than just positive integers, and in such cases an alternative two-dimensional form of the Schr¨odinger equations involving an extra modulation term with a parameter m = 2−n = 0 is discussed.

Énergie des vortex dans un modèle abélien de Higgs en 2+1 dimensions avec un potentiel d’ordre six

Dans ce travail, j’étudierai principalement un modèle abélien de Higgs en 2+1 dimensions, dans lequel un champ scalaire interagit avec un champ de jauge. Des défauts topologiques, nommés vortex, sont créés lorsque le potentiel possède un minimum brisant spontanément la symétrie U(1). En 3+1 dimensions, ces vortex deviennent des défauts à une dimension. Ils ap- paraissent par exemple en matière condensée dans les supraconducteurs de type II comme des lignes de flux magnétique. J’analyserai comment l’énergie des solutions statiques dépend des paramètres du modèle et en particulier du nombre d’enroulement du vortex. Pour le choix habituel de potentiel (un poly- nôme quartique dit « BPS »), la relation entre les masses des deux champs mène à deux types de comportements : type I si la masse du champ de jauge est plus grande que celle du champ sca- laire et type II inversement. Selon le cas, la dépendance de l’énergie au nombre d’enroulement, n, indiquera si les vortex auront tendance à s’attirer ou à se repousser, respectivement. Lorsque le flux emprisonné est grand, les vortex présentent un profil où la paroi est mince, permettant certaines simplifications dans l’analyse. Le potentiel, un polynôme d’ordre six (« non-BPS »), est choisi tel que le centre du vortex se trouve dans le vrai vide (minimum absolu du potentiel) alors qu’à l’infini le champ scalaire se retrouve dans le faux vide (minimum relatif du potentiel). Le taux de désintégration a déjà été estimé par une approximation semi-classique pour montrer l’impact des défauts topologiques sur la stabilité du faux vide. Le projet consiste d’abord à établir l’existence de vortex classi- quement stables de façon numérique. Puis, ma contribution fut une analyse des paramètres du modèle révélant le comportement énergétique de ceux-ci en fonction du nombre d’enroulement. Ce comportement s’avèrera être différent du cas « BPS » : le ratio des masses ne réussit pas à décrire le comportement observé numériquement.

Optimization in the Technological Steps for the Fabrication of Large Area Micromirror Arrays

Micromirror arrays are a very strong candidate for future energy saving applications. Within this work, the fabrication process for these micromirror arrays has been optimized and some steps for the large area fabrication of micromirror modules were performed. At first the surface roughness of the insulation layer of silicon dioxide (SiO2) was investigated. This SiO2 thin layer was deposited on three different type of substrates i.e. silicon, glass and Polyethylene Naphthalate (PEN) substrates. The deposition techniques which has been used are Plasma Enhanced Chemical Vapor Deposition (PECVD), Physical Vapor Deposition (PVD) and Ion Beam Sputter Deposition (IBSD). The thickness of the SiO2 thin layer was kept constant at 150nm for each deposition process. The surface roughness was measured by Stylus Profilometry and Atomic Force Microscopy (AFM). It was found that the layer which was deposited by IBSD has got the minimum surface roughness value and the layer which was deposited by PECVD process has the highest surface roughness value. During the same investigation, the substrate temperature of PECVD was varied from 80° C to 300° C with the step size of 40° C and it was found that the surface roughness keeps on increasing as the substrate holder temperature increases in the PECVD process. A new insulation layer system was proposed to minimize the dielectric breakdown effect in insulation layer for micromirror arrays. The conventional bilayer system was replaced by five layer system but the total thickness of insulation layer remains the same. It was found that during the actuation of micromirror arrays structure, the dielectric breakdown effect was reduced considerably as compared to the bilayer system. In the second step the fabrication process of the micromirror arrays was successfully adapted and transferred from glass substrates to the flexible PEN substrates by optimizing the conventional process recipe. In the last section, a large module of micromirror arrays was fabricated by electrically interconnecting four 10cm×10cm micromirror modules on a glass pane having dimensions of 21cm×21cm.

Efficient topology estimation for large scale optical mapping

Large scale image mosaicing methods are in great demand among scientists who study different aspects of the seabed, and have been fostered by impressive advances in the capabilities of underwater robots in gathering optical data from the seafloor. Cost and weight constraints mean that lowcost Remotely operated vehicles (ROVs) usually have a very limited number of sensors. When a low-cost robot carries out a seafloor survey using a down-looking camera, it usually follows a predetermined trajectory that provides several non time-consecutive overlapping image pairs. Finding these pairs (a process known as topology estimation) is indispensable to obtaining globally consistent mosaics and accurate trajectory estimates, which are necessary for a global view of the surveyed area, especially when optical sensors are the only data source. This thesis presents a set of consistent methods aimed at creating large area image mosaics from optical data obtained during surveys with low-cost underwater vehicles. First, a global alignment method developed within a Feature-based image mosaicing (FIM) framework, where nonlinear minimisation is substituted by two linear steps, is discussed. Then, a simple four-point mosaic rectifying method is proposed to reduce distortions that might occur due to lens distortions, error accumulation and the difficulties of optical imaging in an underwater medium. The topology estimation problem is addressed by means of an augmented state and extended Kalman filter combined framework, aimed at minimising the total number of matching attempts and simultaneously obtaining the best possible trajectory. Potential image pairs are predicted by taking into account the uncertainty in the trajectory. The contribution of matching an image pair is investigated using information theory principles. Lastly, a different solution to the topology estimation problem is proposed in a bundle adjustment framework. Innovative aspects include the use of fast image similarity criterion combined with a Minimum spanning tree (MST) solution, to obtain a tentative topology. This topology is improved by attempting image matching with the pairs for which there is the most overlap evidence. Unlike previous approaches for large-area mosaicing, our framework is able to deal naturally with cases where time-consecutive images cannot be matched successfully, such as completely unordered sets. Finally, the efficiency of the proposed methods is discussed and a comparison made with other state-of-the-art approaches, using a series of challenging datasets in underwater scenarios

Origin and Availability of Large Cavities for Barrow’s Goldeneye (Bucephala islandica), a Species at Risk Inhabiting the Eastern Canadian Boreal Forest

Large secondary-nesting birds such as ducks rely on appropriate cavities for breeding. The main objective of this study was to assess the availability of large cavities and the potential of a managed boreal coniferous landscape to provide nesting trees within the breeding area of the eastern population of Barrow’s Goldeneye (Bucephala islandica), a cavity-nesting species at risk in Canada. Woodpecker surveys were conducted in both conifer and mixed-wood landscapes, and cavities were sought in line transects distributed in unharvested and linear remnant stands of balsam fir (Abies balsamea) and black spruce (Picea mariana) as well as in cutblocks. No Pileated Woodpeckers (Dryocopus pileatus) were detected in the breeding area of Barrow’s Goldeneye, but the species was present in the nearby lowland area in which trembling aspen (Populus tremuloides) is abundant. Only 10 trees (0.2% of those sampled) supported cavities considered suitable for Barrow’s Goldeneye in terms of dimensions and canopy openness. Most of the suitable cavities found during this study were nonexcavated apical (chimney) cavities in relatively short snags that showed advanced states of decay. A diameter-at-breast-height threshold was determined for each tree species, after which the probability of cavity occurrence was enhanced in terms of potential cavity trees for Barrow’s Goldeneye. Remnant linear forest sites had lower potential tree densities than did their unharvested equivalents. Large cavities were thus a rare component in this boreal landscape, suggesting that they may be a limiting factor for this population at risk. Current even-aged forest management that mainly relies on clear-cut practices is likely to further reduce the potential of this landscape to provide trees with suitable cavities.