Genomic tests of the species‐pump hypothesis: Recent island connectivity cycles drive population divergence but not speciation in Caribbean crickets across the Virgin Islands

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111904/1/evo12667-sup-0001-SuppMat.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/111904/2/evo12667.pd

Species‐specific responses to island connectivity cycles: refined models for testing phylogeographic concordance across a Mediterranean Pleistocene Aggregate Island Complex

The contribution of Pleistocene sea level changes to diversification patterns in archipelagos around the world, and specifically whether the repeated cycles of island connectivity and isolation acted as a ‘species pump’ is debated. The debate has been perpetuated in part because of the type of evidence used to evaluate the species‐pump hypothesis. Specifically, existing tests of the ‘Pleistocene Aggregate Island Complex’ (PAIC) model of diversification interpret the lack of concordant divergence times among multiple codistributed taxa as a rejection of the PAIC model. However, the null expectation of concordance disregards taxon‐specific ecological traits and geographic characteristics that may affect population persistence and gene flow among islands. Here, we study the factors affecting population divergence in thirteen flightless darkling beetle species (Coleoptera: Tenebrionidae) across the PAIC system of the Cycladic plateau in the Aegean archipelago. Based on isolation‐by‐resistance analyses, hierarchical amova and the degree of genealogical sorting on individual islands, we identify a major effect of bathymetry and habitat stability on the levels of genetic divergence across the PAIC, with island size and body size playing a secondary role as well. We subsequently use bathymetric maps and habitat association to generate predictions about the set of islands and group of taxa expected to show phylogeographic concordance. We test these predictions using hierarchical approximate Bayesian computation and show how our interpretations regarding the role of PAICs as drivers of divergence change when relying on a null expectation of concordance compared to a refined model that takes geography and ecological traits into account.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/113138/1/mec13305.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/113138/2/mec13305_am.pd

Searching edges in the overlap of two plane graphs

Consider a pair of plane straight-line graphs, whose edges are colored red and blue, respectively, and let n be the total complexity of both graphs. We present a O(n log n)-time O(n)-space technique to preprocess such pair of graphs, that enables efficient searches among the red-blue intersections along edges of one of the graphs. Our technique has a number of applications to geometric problems. This includes: (1) a solution to the batched red-blue search problem [Dehne et al. 2006] in O(n log n) queries to the oracle; (2) an algorithm to compute the maximum vertical distance between a pair of 3D polyhedral terrains one of which is convex in O(n log n) time, where n is the total complexity of both terrains; (3) an algorithm to construct the Hausdorff Voronoi diagram of a family of point clusters in the plane in O((n+m) log^3 n) time and O(n+m) space, where n is the total number of points in all clusters and m is the number of crossings between all clusters; (4) an algorithm to construct the farthest-color Voronoi diagram of the corners of n axis-aligned rectangles in O(n log^2 n) time; (5) an algorithm to solve the stabbing circle problem for n parallel line segments in the plane in optimal O(n log n) time. All these results are new or improve on the best known algorithms.Comment: 22 pages, 6 figure

Mineralogy and chemistry of amphiboles and thermobarometry of Papikion Mt pluton, Rhodope, Northern Greece.

O πλουτωνίτης του Παπικίου Όρους που διεισδύει στο Δόμο του Κάρδαμου, αποτελείται από Bi, Hbl και Bi-Hbl τύπους πετρωμάτων. Σε αυτή την εργασία μελετάται η σχέση μεταξύ των αμφιβόλων του κάθε πετρογραφικού τύπου που τις περιέχει. Οι αμφίβολοι του κεροστιλβικού γρανοδιορίτη (Hbl GRD), του βιοτιτικού-κεροστιλβικού διορίτη (Bi-Hbl DR)και του κεροστιλβικού διορίτη (Hbl DR) ταξινομούνται κυρίως ως μαγνησιοκεροστίλβες και σιδηροκεροστίλβες και οι αμφίβολοι του βιοτιτικούκεροστιλβικού γρανοδιορίτη (Bi-Hbl GRD) ως σιδηροεδενίτες και χαστινγκσίτες. Πρέπει να σημειωθεί ότι ορισμένα δείγματα περιέχουν κρυστάλλους αμφιβόλου που παρουσιάζουν κοσκινινοειδή υφή με χαλαζία. Αυτές οι κοσκινοειδείς αμφίβολοι δεν διαφέρουν χημικά από τις υπόλοιπες. Η υφή αυτή μπορεί να προέρχεται από την αποδόμηση των φεμικών ορυκτών ενός αφομοιωμένου ξενόλιθου όπως οι πυρόξενοι αλλά και η ίδια η κεροστίλβη, αφήνοντας πίσω χαλαζία. Χρησιμοποιώντας το γεωβαρόμετρο Al στην κεροστίλβη και το γεωθερμόμετρο κεροστίλβης-πλαγιοκλάστου, υπολογί-στηκαν ελάχιστη πίεση κρυστάλλωσης 4,6 - 5,2 kbar και θερμοκρασίες 700 - 740 °C για το Bi-Hbl DR και 6,4 έως 7,4 kbar και θερμοκρασίες από 620 έως 700 °C στην ομάδα DR.. O Hbl GRD δείχνει τις χαμηλότερες τιμές Ρ-Τ, με μέση πίεση κρυστάλλωσης περίπου 3 kbar και με μέση θερμοκρασία περίπου 600 °C. Papikion Mt pluton which intrudes Kardamos Dome, consists of biotite (Bi), hornblende (Hbl) and biotite-hornblende (Bi-Hbl) bearing rock types. In this work the relationship among the amphiboles of each Hbl-bearing rock type is studied. Moreover, their minimum crystallization pressure and temperature are estimated. The amphiboles of the Hbl granodiorite (GRD), the Bi-Hbl diorite (DR) and the Hbl diorite (DR) are classified mainly as magnesiohornblende and ferrohornblende and the amphiboles of the Bi-Hbl GRD as ferroedenite and hanstingsite. It is to note that some samples contain amphibole crystals showing a sieved texture with quartz. These sieved amphiboles have no chemical differences from the rest amphibole crystals. This texture can probably derive from the breakdown of mafic minerals of an assimilated xenolith such as pyroxenes and hornblende itself, leaving quartz. Using the Al-in-hornblende geobarometer and the plagioclase-hornblende geothermometer), minimum crystallization pressures from 4.6 to 5.2 kbar and temperatures from 700 to 740 °C were estimated for the Bi-Hbl GRD. The DR shows crystallization pressures ranging from 6.4 to 7.4 kbar and temperatures ranging from 620 to 700 °C. The Hbl GRD shows the lowest P-T values, thus an average crystallization pressure about 3 kbar and an average temperature about 600 °C were estimated

Superconductivity and spin-glass like behavior in system with Pd sheet sandwiched between graphene sheets

Pd-metal graphite (Pd-MG) has a layered structure, where each Pd sheet is sandwiched between adjacent graphene sheets. DC magnetization and AC magnetic susceptibility of Pd-MG have been measured using a SQUID magnetometer. Pd-MG undergoes a superconducting transition at $T_{c}$ ($= 3.63 \pm 0.04$ K). The superconductivity occurs in Pd sheets. The relaxation of $M_{ZFC}$ (aging), which is common to spin glass systems, is also observed below $T_{c}$. The relaxation rate $S(t)$ shows a peak at a characteristic time $t_{cr}$, which is longer than a wait time $t_{w}$. The irreversibility between $\chi_{ZFC}$ and $\chi_{FC}$ occurs well above $T_{c}$. The susceptibility $\chi_{FC}$ obeys a Curie-Weiss behavior with a negative Curie-Weiss temperature ($-13.1 \leq \Theta \leq -5.4$ K). The growth of antiferromagnetic order is limited by the disordered nature of nanographites, forming spin glass-like behavior at low temperatures in graphene sheets.Comment: 21 pages, 15 figures; submitted to J. Phys.: Condensed Matte

Negative Giant Longitudinal Magnetoresistance in NiMnSb/InSb: An interface effect

We report on the electrical and magneto-transport properties of the contact formed between polycrystalline NiMnSb thin films grown using pulsed laser deposition (PLD) and n-type degenerate InSb (100) substrates. A negative giant magnetoresistance (GMR) effect is observed when the external magnetic field is parallel to the surface of the film and to the current direction. We attribute the observed phenomenon to magnetic precipitates formed during the magnetic film deposition and confined to a narrow layer at the interface. The effect of these precipitates on the magnetoresistance depends on the thermal processing of the system.Comment: 14 pages, 4 figure

Illumination diagnosis for retrieval of reflections from ambient-noise seismic data in the Siilinjärvi mining site, Finland

Reflection seismic methods are becoming popular in mineral exploration, because they allow high-resolution delineation of the exploration targets, even at great depths. Seismic interferometry can be used to retrieve reflections from passive seismic data, removing the need for active seismic sources and, therefore, reducing the cost and environmental impact of exploration. The retrieval of reflections can be challenging, since passive seismic records are typically dominated by surface waves. Therefore, illumination diagnosis, a method which allows the isolation of the portions of the passive data where body-wave signals are stronger, can be a valuable step that improves the quality of the reflections retrieved from seismic interferometry and reduces the overall computational cost of the processing stage. Here, we validate the performance of the method to effectively isolate the portions of the passive data dominated by body waves and apply it on an ambient-noise seismic dataset acquired in the Siilinjärvi mining site in Finland