bluuebunny/crossref_metadata_2025 huggingface dataset:
Petrography of coarse clastic facies, Fisset Brook Formation and Horton Group (Upper Devonian-Lower Carboniferous), Lake Ainslie and Margaree map areas, Cape Breton Island, Nova Scotia
Authors: Hein F J , Arnott A M
Published: October 2013

In central and western Cape Breton Island, Nova Scotia, the Fisset Brook Formation and the Horton Group comprise the initial syn-rift volcanic and nonmarine clastic deposits of the Magdalen Basin. Distinction of the various coarse clastic successions is difficult
in areas of geological complexity, such as near fault zones or pre-Carboniferous highlands. Petrographically, the following distinctions are made: Fisset Brook -- quartzofeldspathic subarkose to arkosic arenite, with white-buff "bleached" coarse clasts; Craignish quartz-rich facies -- quartz arenite
and subarkose; Craignish green polymict facies -- more feldspathic, subarkose and arkosic arenite, with green-white altered matrix; Craignish red polymict facies -- more quartz-rich, subarkose and arkosic arenite, with red-altered hematitic matrix, and red-stained quartz-grains; Judique -- tan and
brown subarkose and sublitharenite, with black shale intraclasts; Strathlorne -- grey, less feldspathic subarkose/sublitharenite or arkose; Ainslie -- grey with red, compositionally varied arenite, ranging from quartz arenite, to arkose and lithic arenite.
A preliminary report on the stratigraphy of Late Namurian to Stephanian fluviatile stratain southeastern New Brunswick
Authors: Johnson S C
Published: October 2013

Late Namurian to Stephanian strata in southeastern New Brunswick have traditionally been assigned to the Enragé, Boss Point, Salisbury, Richibucto, and Tormentine formations, equivalent to parts of the recently redefined Cumberland and Pictou groups. Recent
mapping, palynology studies, and revisions made in the type localities of the Cumberland and Pictou groups have necessitated the reassignment of some of these strata. Preliminary results indicate the Salisbury and Richibucto formations are not facies equivalent and need to be formally redefined.
Spore assemblages in the Richibucto Formation are mid-Westphalian C to Stephanian whereas those in the Salisbury Formation are latest Westphalian B to Westphalian C. Based on similar lithostratigraphy, the Richibucto Formation is tentatively correlated with the Malagash Formation which forms the top
of the Cumberland Group in the Cumberland subbasin. The overlying Tormentine Formation would therefore be equivalent to the lowermost Pictou Group in Nova Scotia.
The pseudo-geological log: using geophysical logs as an aid to geological logging in volcanogenic massive sulphides
Authors: Killeen P G , Mwenifumbo C J , Elliott B E
Published: October 2013

Geophysical borehole logs, which measure the physical properties of the rocks surrounding the hole, can be used as an aid to geological core logging, because they are continuous with no missing sections, and because they show changes that are not detectable with
the naked eye. Three examples of the application of borehole geophysical logs to the problem of core logging in areas of volcanogenic massive sulphide deposits, are discussed. The Mudhole prospect in Newfoundland is a simple case of the obvious relation between geophysical logs and geological logs.
In the Buttle Lake area of British Columbia, the experience gained from the Mudhole prospect was used to derive a pseudo-geological log based on the gamma-ray log. The pseudo-geological log was improved further in the Kam-kotia mine area in Ontario by using three geophysical parameters. In all three
cases, the geological interpretation from the geophysical logs was subjective. An objective, computer-based method of deriving the pseudo-geological log, as a tool for the geologist, is being investigated.
Carlin-type gold deposits and their potential occurrence in the Canadian Cordillera
Authors: Poulsen K H
Published: October 2013

Carlin-type deposits are characterized by pyrite and micron-sized gold particles disseminated in de-calcified zones in otherwise carbonate-bearing rocks. Silicification in the form of stratabound jasperoid replacements of bedded rocks and as discordant
hydrothermal breccias is a common affiliate of ore. Carlin-type deposits are commonly enriched in arsenic, antimony, and mercury and this is reflected in part by the presence of coarse stibnite and orpiment / realgar in late-stage veins. Carlin-type deposits are controlled structurally by thrusts,
upright folds and, most important, high-angle normal faults. They occur in distinct mineral belts in the Paleozoic miogeocline of the western United States where they co-exist with Paleozoic sedex deposits and Mesozoic through Cenozoic intrusion-related porphyry Cu-Mo, skarn Cu, skarn Au, skarn
Pb-Zn, and vein and manto Ag-Pb-Zn deposits. Although definitive examples of Carlin-type deposits are unknown in Canada, analogous geological environments exist in the Omineca Belt of the Canadian Cordillera.
Middle Triassic (Ladinian) volcanic strata in southern Yukon Territory, and their Cordilleran correlatives
Authors: Hart C J R , Orchard M J
Published: October 2013

Geological mapping of Whitehorse Trough strata of Stikinia in southern Yukon has identified an unusual succession dominated by mafic volcanic rocks. The succession, here termed the Joe Mountain volcanic complex, is at least 3 km thick and underlies a region
approximately 20 by 40 km. The section comprises pillowed, massive and autobrecciated basalt flows, massive microdiorite and diabase, clastic and calcareous sedimentary rocks and gabbro. Major element geochemistry suggests that the volcanic rocks are dominantly sub-alkalic, iron-enriched tholeiitic
basalt and basaltic andesite. Conodonts obtained from intercalated carbonate strata indicate that the Joe Mountain volcanic complex is Middle Triassic (Ladinian) in age. Rocks of this age are poorly represented within the accreted Cordilleran terranes. Correlative strata are dominated by chert and
argillite, and/or different volcanic suites. The Joe Mountain volcanic strata have no obvious Cordilleran counterparts.
Structural evolution and rock types of the Slide Mountain and Yukon-Tanana terranes in the Campbell Range, southeastern Yukon Territory
Authors: Plint H E , Gordon T M
Published: October 2013

Mapping at 1:50 000 scale in the Campbell Range, Yukon Territory examined the Finlayson Lake fault zone and the Slide Mountain and Yukon-Tanana terranes. Map units identified are: (a)Yukon-Tanana terrane: DTp chlorite-actinolite phyllite, DTa argillite, DTc
metachert and slate; (b) Slide Mountain terrane: DPsc and DPsp metachert, argillite, and phyllite, DPsg greenstone, breccia, gabbro, and metasedimentary rocks, DPslg leucogabbro, and DPss serpentinite; and (c) Earn Group: DMec metachert and argillite, and DMes sandstone, siltstone, and shale.

Unit DPsg is thrust over DTp and DTa in the west and DPsc in the east. The map pattern of DTc suggests a klippe preserved from erosion by normal faulting along its southern boundary. These structures may represent a flower structure or an originally east-directed thrust sequence disrupted by
west-directed back thrusts with continued shortening.
Late Tertiary to Quaternary volcanism in the Atlin area, northwestern British Columbia
Authors: Edwards B R , Hamilton T S , Nicholls J , Stout M Z , Russell J
K , Simpson K
Published: October 2013

We extend the previous descriptions and report preliminary interpretations for age constraints based on field data for several occurrences of Late Tertiary to Quaternary volcanic deposits in the Atlin area: Ruby Mountain, Cracker Creek, Volcanic Creek, Llangorse
Mountain, and Chikoida Mountain. The deposits include a collection of extensively eroded feeder pipes (Chikoida), a tall, columnar-jointed vent plug or a vent proximal lava flow (Llangorse), isolated cinder cones with associated lava flows (Cracker and Volcanic creeks), and a partly eroded
stratovolcano (Ruby Mountain). The volcanic products at two localities, Ruby and Chikoida mountains, contain crustal xenoliths. Peridotite xenoliths are present at all five localities.

Two of the deposits, Volcanic and Cracker creeks, appear to be postglacial, whereas Ruby and Llangorse mountains have undergone moderate glacial modification. An approximate age for the bodies exposed at Chikoida Mountain is indeterminate but they appear to have been extensively
glaciated.
Kshwan Glacier rock avalanche, southeast of Stewart, British Columbia
Authors: Mauthner T E
Published: October 2013

During the winter of 1992-1993, a rock avalanche slid onto and crossed the Kshwan Glacier. Between 1 and 3 million cubic metres of hornblende-biotite granodiorite of the Eocene Kshwan Glacier pluton detached along joints from an oversteepened slope debuttressed
by downwasting and retreating glaciers. Modelling of the Kshwan Glacier rock avalanche and comparison with other avalanches suggest that it had a coefficient of friction and runout characteristic of rock avalanches occurring in glacial environments. Examination of the geological and geomorphic
conditions causing mass movements such as the Kshwan Glacier rock avalanche substantiates the need for caution in the development of recently glaciated terrain such as in the Coast Mountains.
Nechako Project overview, central British Columbia
Authors: Struik L C , McMillan W J
Published: October 2013

The Geological Survey of Canada and British Columbia Geological Survey Branch together with researchers in university and industry have initiated new geological mapping in central British Columbia (NTS 93F, 93K, and parts of 93G, 93L, 93M, 93N). The project is
co-ordinated and financially augmented through the Geological Survey of Canada's National Mapping Program (NATMAP). Bedrock and surficial mapping are enhanced by geophysical and geochemical interpretations and site studies.
Time-domain electromagnetic surveys in drift covered regions of the Fawnie Creek map area, British Columbia
Authors: Best M E , Levson V M , Diakow L
Published: October 2013

Time-domain electromagnetic surveys were carried out at 3 sites in the Nechako Plateau of British Columbia to investigate the use of electromagnetic methods for mapping the contact between granitic and basaltic rocks in drift-covered areas. This is difficult
because resistive environments have a low EM signal-to-noise (S/N) ratio.

The results indicate that electromagnetic methods can map changes in bedrock resistivity, even with drift thickness in excess of 100 m. Resistivity effects associated with the contact, e.g., alteration and/or fracturing, were observed at site 1. Changes in bedrock resistivity at site 2 may be
associated with the contact as well. In addition, a bedrock conductor was located near this contact.

The EM results at these sites are consistent with the interpretation of a high mineral potential for the area, based on bedrock mapping as well as till, lake sediment, and rock geochemistry results.
Albian-Cenomanian conglomerates along the Intermontane/Insular superterrane boundary, Canadian Cordillera, British Columbia: a critical test for large-scale terrane translation?
Authors: Mahoney J B , Monger J W H , Hickson C J
Published: October 2013

The mid-Cretaceous-early Tertiary paleogeography of the Canadian Cordillera generates intense debate among geoscientists forced to evaluate two contradictory data sets: 1) paleomagnetic data suggest large-scale northward translation of the Insular and
Intermontane superterranes between 80-60 Ma; 2) geological data indicate significantly smaller displacements. This paper outlines a critical stratigraphic test of a prediction of the large-scale translation hypothesis. Nonmarine, chert and volcanic conglomerates of Albian-Cenomanian age (ca. 100-90
Ma) occur on both the Intermontane superterrane and within the mid-Cretaceous collisional orogen (amalgamated Methow, Bridge River, and Cadwallader terranes) associated with the Insular superterrane. Different magnitudes of displacement of each superterrane require that the conglomerate units were
deposited in entirely different sedimentary systems and are not correlative. This paper outlines a multidisciplinary investigation, including lithostratigraphy, clast geochemistry and isotopic signature, detrital zircon studies, palynology, and paleomagnetic studies, that will examine potential
correlations among Albian-Cenomanian strata.
U-Pb zircon ages of the Island Copper deposit intrusions, norther Vancouver Island, British Columbia
Authors: Ross K V , Friedman R M , Dawson K M , Leitch C H B
Published: October 2013

A rhyodacite quartz-feldspar porphyry dyke complex, comprising three phases, hosts the Island Copper mine, a Cu-Mo-Au island arc-type porphyry deposit. New zircon U-Pb age dates for the phases, bracket the timing of mineralization to ca. 169-166 Ma and include:
168.5 + 0.3/-1.7 Ma for the earliest, generally premineral phase; 168.5 ± 0.6 Ma for the second Cu-Mo-Au mineralizing phase; and 166.2 ± 0.7 Ma for the third, generally barren phase. The older mineralized dykes are coeval with the adjacent Rupert stock to the east, and the dates are
permissive of previously proposed cogenesis. These ages are also nearly coeval with the youngest intrusions of the Island Intrusions and with arc volcanic rocks of the upper Bonanza Group on northern Vancouver Island. These and other Middle Jurassic magmatic rocks define an arc that extends eastward
across the southern Coast Belt and northward through the northern Insular and Coast belts to Alaska.
Quaternary stratigraphy of Taseko valley, south-central British Columbia
Authors: Plouffe A , Levson V , Giles T
Published: October 2013

The Quaternary succession in Taseko valley, near the confluence of Taseko River and Tête Angela Creek, includes three major units (in decreasing age): (1) advance phase sediments, (2) till and (3)glaciofluvial and fluvial sand and gravel. It is suggested
that at the onset of the last (Fraser) glaciation, as ice advanced down Taseko valley, there was a lake at the ice front, impounded by an ice or sediment dam located farther downstream. The dam may have formed when prograding outwash or valley glaciers, derived from mountainous areas that flank
Fraser and Chilcotin valleys, blocked the drainage. The Taseko valley stratigraphy is correlated with stratigraphies at other sites in Chilcotin and Fraser River valleys where advance phase glaciolacustrine sediments have been reported.
New stratigraphic and tectonic interpretations, north Okanagan Valley, British Columbia
Authors: Thompson R I , Daughtry K L
Published: October 2013

Palaeozoic stratigraphic markers on both sides of the north Okanagan Valley (82L) suggest the valley is a graben that underwent relatively little extension. Interpretation of a shallow west-dipping extension fault along the valley trace cannot be supported by the
local geology.

Radiometric dates from an undeformed pluton and pegmatite mapped across the inferred trace of the Okanagan Fault, south of Wood Lake, cut the regional foliation and constrain the fabric as older than latest Jurassic.

Schist and gneiss that comprise the Shuswap Metamorphic Complex (formerly Monashee Group) extend northwest across the north Okanagan Valley to Little Shuswap Lake, implying stratigraphic equivalence between the Monashee Group and the Silver Creek Formation.

The Tsalkom, Mara, and Sicamous formations may outcrop at Keefer Gulch, 10 km east of Vernon. The Sicamous Formation may be Permian. Lithologically, the Mara Formation strongly resembles parts of the Eagle Bay Formation.
Neotectonic stress orientation indicators in southwestern British Columbia
Authors: Bell J S , Eisbacher G H
Published: October 2013

Possible indicators for in situ rock stress orientation were identified and analyzed in roadcuts and on glacier forefields in southwestern British Columbia as part of the Geological Survey of Canada's Cordilleran Neotectonic Map Project. A particular effort was
made to obtain readings from plutonic and high-grade metamorphic rocks of the Southern Coast Belt and the Omineca Belt. At all sites, great care had to be taken in order to avoid measuring features that could have been influenced by rock fabric, pre- Pleistocene structures, or local topography. Data
were gathered from offset preshear boreholes, axial fractures propagated from preshear boreholes, and stress-controlled breakage fractures in artificial roadcuts, and from neotectonic faults, hairline fractures, and glacial neotectonic plucking fractures on glacier
forefields.
Archean crustal evolution in the central Minto block, northern Quebec
Authors: Skulski T , Percival J A , Stern R A
Published: October 2013

The central Minto block contains three volcano-sedimentary successions. Near Lake Qalluviartuuq, an isotopically primitive (2.83 Ga Nd +3.8 to +2.3) 2.83 Ga volcano-plutonic sequence comprises depleted tholeiitic basalts, anorthositic gabbro, and
diorite-granodiorite that is unconformably overlain by <2.77 Ga conglomerates. Overlying the conglomerate is a more evolved (2.76 Ga Nd +1.8) calc-alkaline sequence of pillow basalts, andesites, and peridotite cut by 2.73 Ga diorite. To the west, and in inferred tectonic contact, the
sediment-dominated Kogaluc sequence includes both isotopically evolved calc-alkaline rocks (2.76 Ga Nd +1.6 to -0.1) including <2.76 Ga rhyolitic tuff, pillowed andesites, and 2.76 Ga quartz-feldspar porphyry, and less abundant, depleted tholeiitic basalts (2.76
GaeNd +2.4). These are interlain with sedimentary rocks including banded iron-formation, quartzite, and metagreywacke. Calc-alkaline batholiths include 2.78 Ga pyroxene-bearing intermediate
and felsic plutons (2.78 Ga Nd <+2.7) and younger, peraluminous tonalites ( Nd <+1.3). Late, 2.73 Ga peraluminous granitoids are isotopically evolved (2.725 Ga Nd -1.6).
Geology and age of the Lac à la Perdrix fenite, southern Gatineau district, Quebec
Authors: Hogarth D D , van Breemen O
Published: October 2013

The Lac à la Perdrix fenite lies in the Central Metasedimentary Belt of the Grenville Province. This 30 m wide fenite, adjacent to a narrow calciocarbonatite sill, replaces diopside-oligoclase gneiss and is composed of magnesio-arfvedsonite, aegirine,
microcline, albite, and fluorapatite. Near the contact with carbonatite, it contains appreciable monazite and barite whereas aegirine virtually disappears.

Fenitization probably took place early in the igneous stage of carbonatite development. A Pb/U monazite age of 1026±2 Ma is thought to date fenite formation. Together with published data, this age shows that carbonatite intruded metamorphic rocks near the close of the Grenville
Orogeny.
Preliminary chronostratigraphy of the Tetagouche and Fournier groups in northern New Brunswick
Authors: Sullivan R W , van Staal C R
Published: October 2013

Seven U-Pb zircon ages of volcanic rocks from northern New Brunswick are reported and a preliminary stratigraphy of the middle Ordovician Tetagouche and Fournier groups is presented. Deposition of the Tetagouche Group started with calcareous rocks of the
Vallée Lourdes Formation in the Late Arenig (>470 Ma). Quartz- and feldspar-phyric felsic volcanic rocks of the immediately overlying Nepisiquit Falls Formation yielded U-Pb zircon ages between ca. 471 and 469 Ma. These volcanic rocks are time stratigraphic equivalents of the
feldspar-phyric dacites of the Spruce Lake Formation, which yielded a U-Pb zircon age of ca. 470 Ma, and tholeiitic and alkalic pillow basalts of the structurally overlying Canoe Landing Lake Formation. The final phase of rhyolitic to dacitic volcanism is marked by the emplacement of distinct
quartz- and feldspar-phyric dacitic porphyries at ca. 465 Ma, thus limiting silicic volcanism to the Late Arenig and Ilanvirn. During the Ilandeilo and Caradoc (ca. 464-457 Ma) volcanic activity in the Tetagouche Group was characterized by extrusion of alkali basalts and minor comendites,
interlayered with dark shales and siltstones of the Boucher Brook Formation. Oceanic crust of the Fournier Group was also formed during this period.
Modified chemical procedures for the extraction and purification of uranium from titanite, allanite, and rutile in the Geochronology Laboratory, Geological Survey of Canada
Authors: David W J , McNicoll V J , Bellerive D R , Santowski K , Scott D J
Published: October 2013

A procedure for the extraction and purification of U from Fe-, Ca-, and Ti-bearing minerals using U/TEVAúSPECTM extraction chromatographic material is described. The procedure has several advantages over previous techniques: it requires less time, uses
much smaller quantities of high-purity acids, and yields improved U analysis by thermal ionization mass spectrometry.
Sm-Nd isotopic study on mafic volcanic rocks from the Rankin Inlet and Tavani regions, District of Keewatin, Northwest Territories
Authors: Thériault R J , Tella S
Published: October 2013

Sm-Nd isotopic compositions are presented on eleven Late Archean mafic volcanic whole rock samples of the Rankin Inlet and Tavani areas of the eastern Rankin-Ennadai greenstone belt. Three samples from the lower volcanic cycle of the Rankin Inlet Group yielded
eNd(2.66 Ga) values of -1.1 to +1.6, and 147Sm/144Nd ratios from 0.1289 to 0.1410, suggesting interaction of the mafic magmas with an older LREE-enriched crustal contaminant. Rocks of the upper volcanic cycle yielded eNd(2.66 Ga) values of +1.8 to +4.5 and 147Sm/144Nd ratios of 0.1374 to 0.1999, and
are relatively uncontaminated compared to the lower volcanic cycle. The presence of crustally contaminated volcanic rocks in the lower volcanic cycle indicates that it may have been underlain by older continental-type basement rocks, or that its mantle source was contaminated with crustally-derived
fluids or sediments. Four samples from the Tavani area have eNd(2.68 Ga) values of +2.1 to +3.4, indicating derivation from depleted mantle sources, with no obvious interaction with older LREE-enriched crust. One of the five samples from the Tavani area yielded a eNd(2.68 Ga) value of +0.6, raising
the possibility of minor contamination from an older crustal component.
Timing of early deformation within the long-lived Elbow Lake Shear Zone, Trans-Hudson Orogen, Manitoba
Authors: Ansdell K M , Ryan J J
Published: October 2013

The Elbow Lake Shear Zone forms a strand within a high strain corridor in the central Flin Flon belt that records an episodic deformational history in excess of 100 Ma. Three new U-Pb zircon ages are presented to bracket the timing of the earliest deformation
within this zone, and their significance is interpreted in terms of the development of the Amisk collage. The earliest recognized fabrics (S1) are mylonites within gabbro-diabase-basalt assemblages which are crosscut at right angles by a suite of pink tonalite dykes. Zircons from one of these dykes
yielded discordant ages, which suggest that the dyke could be as old as 1870 ± 2 Ma. In the same region, a pair of grey tonalite dykes both yielded high precision ages of about 1866 Ma, but they have different amounts of strain. The earlier dyke was intensely sheared, then intruded by the
weakly foliated dyke. Both dykes then formed boudins at a scale of tens of metres during subsequent shear episodes. The variable states of strain in dykes of the same age is good evidence for synkinematic (D2) dyke emplacement at 1866 Ma, during initial shortening of the successor arc built upon
the Amisk collage.
Fetal Cholelithiasis: A Diagnostic Update and a Literature Review
Authors: Triunfo Stefania , Rosati Paolo , Ferrara Pietro , Gatto Antonio , Scambia Giovanni
Published: October 2013

Fetal gallstones and cholelithiasis, detected by routine third trimester ultrasound, have been described in the literature with controversial clinical significance. We report a case of fetal cholelithiasis detected at 35 weeks gestation during a routine scan. The diagnosis was performed using an integrated 2-dimensional (2-D) and 3-dimensional (3-D) ultrasound approach in order to obtain a better definition of the fetal gallbladder and its content. A neonatal follow-up was achieved. The present study has a twofold purpose: firstly, to update the diagnostic approach using the innovative 3-D modalities and secondly, to review the management of this condition during fetal and postnatal life.
Big Brains, Meat, Tuberculosis, and the Nicotinamide Switches: Co-Evolutionary Relationships with Modern Repercussions?
Authors: Williams Adrian C. , Dunbar Robin I.M.
Published: October 2013

Meat-eating was a game changer for human evolution. We suggest that the limiting factors for expanding brains earlier were scarcities of nicotinamide and tryptophan. In humans and some other omnivores, lack of meat causes these deficiencies. Nicotinamide adenine dinucleotide (NADH) is necessary to synthesize adenosine triphosphate (ATP) via either glycolysis or via the mitochondrial respiratory chain. NAD consumption is also necessary for developmental and repair circuits. Inadequate supplies result in “de-evolutionary” brain atrophy, as seen with pellagra. If trophic nicotinamide/tryptophan was a “prime mover” in building bigger brains, back-up mechanisms should have evolved. One strategy may be to recruit extra gut symbionts that produce NADH precursors or export nicotinamide (though this may cause diarrhea). We propose a novel supplier TB that co-evolved early, which did not originally and does not now inevitably cause disease. TB has highly paradoxical immunology for a pathogen, and secretes and is inhibited by nicotinamide and its analogue, isoniazid. Sharp declines in TB and diarrhea correlated with increased meat intake in the past, suggesting that dietary vitamin B3 and tryptophan deficiencies (also associated with poor cognition and decreased lifespans) are still common where meat is unaffordable.
A genericity theorem for algebraic stacks and essential dimension of hypersurfaces
Authors: Reichstein Zinovy , Vistoli Angelo
Published: October 2013

We compute the essential dimension of the functors Forms

_{n,d}

and Hypersurf

_{n, d}

of equivalence classes of homogeneous polynomials in

n

variables and hypersurfaces in

\mathbb P^{n-1}

, respectively, over any base field

k

of characteristic

0

. Here two polynomials (or hypersurfaces) over

K

are considered equivalent if they are related by a linear change of coordinates with coefficients in

K

. Our proof is based on a new Genericity Theorem for algebraic stacks, which is of independent interest. As another application of the Genericity Theorem, we prove a new result on the essential dimension of the stack of (not necessarily smooth) local complete intersection curves.
Modular representations of finite groups with trivial restriction to Sylow subgroups
Authors: Balmer Paul
Published: October 2013

Let

k

be a field of characteristic

p

. Let

G

be a finite group of order divisible by

p

and

P

a

p

-Sylow subgroup of

G

. We describe the kernel of the restriction homomorphism

T(G)\to T(P)

, for

T(-)

the group of endotrivial representations. Our description involves functions

G\to k^\times

that we call weak

P

-homomorphisms. These are generalizations to possibly non-normal

P\leq G

of the classical homomorphisms

G/P\to k^\times

appearing in the normal case.
On a magnetic characterization of spectral minimal partitions
Authors: Helffer Bernard , Hoffmann-Ostenhof Thomas
Published: October 2013

Given a bounded open set

\Omega

in

\mathbb R^n

(or in a Riemannian manifold) and a partition of

\Omega

by

k

open sets

D_j

, we consider the quantity

\max_j \lambda(D_j)

where

\lambda(D_j)

is the ground state energy of the Dirichlet realization of the Laplacian in

D_j

. If we denote by

\mathfrak L_k(\Omega)

the infimum over all the

k

-partitions of

\max_j \lambda(D_j)

, a minimal

k

-partition is then a partition which realizes the infimum. When

k=2

, we find the two nodal domains of a second eigenfunction, but the analysis of higher

k

's is non trivial and quite interesting. In this paper, we give the proof of one conjecture formulated in [5] and [16] about a magnetic characterization of the minimal partitions when

n=2

.
Quasi-isometric maps and Floyd boundaries of relatively hyperbolic groups
Authors: Gerasimov Victor , Potyagailo Leonid
Published: October 2013

We describe the kernel of the canonical map from the Floyd boundary of a relatively hyperbolic group to its Bowditch boundary. Using the Floyd completion we further prove that the property of relative hyperbolicity is invariant under quasi-isometric maps. If a finitely generated group

H

admits a quasi-isometric map

\varphi

into a relatively hyperbolic group

G

then

H

is itself relatively hyperbolic with respect to a system of subgroups whose image under

\varphi

is situated within a uniformly bounded distance from the right cosets of the parabolic subgroups of

G

. We then generalize the latter result to the case when

\varphi

is an

\alpha

-isometric map for any polynomial distortion function

\alpha.

As an application of our method we provide in the Appendix a new short proof of a basic theorem of Bowditch characterizing hyperbolicity.
On the dimension of $p$-harmonic measure in space
Authors: Lewis John L. , Nyström Kaj , Vogel Andrew
Published: October 2013

Let

\Omega\subset\mathbb {R}^{n}

,

n\geq 3

, and let

p

,

1 < p < \infty

,

p \not = 2

, be given. In this paper we study the dimension of

p

-harmonic measures that arise from non-negative solutions to the

p

-Laplace equation, vanishing on a portion of

\partial\Omega

, in the setting of

\delta

-Reifenberg flat domains. We prove, for

p \geq n

, that there exists

\tilde\delta=\tilde\delta(p,n)>0

small such that if

\Omega

is a

\delta

-Reifenberg flat domain with

\delta<\tilde\delta

, then

p

-harmonic measure is concentrated on a set of

\sigma

-finite

H^{n-1}

-measure. We prove, for

p \geq n

, that for sufficiently flat Wolff snowflakes the Hausdorff dimension of

p

-harmonic measure is always less than

n-1

. We also prove that if

2<p<n

, then there exist Wolff snowflakes such that the Hausdorff dimension of

p

-harmonic measure is less than

n-1

, while if

1<p<2

, then there exist Wolff snowflakes such that the Hausdorff dimension of

p

-harmonic measure is larger than

n-1

. Furthermore, perturbing off the case

p = 2,

we derive estimates when

p

is near 2 for the Hausdorff dimension of

p

-harmonic measure.
Operations between sets in geometry
Authors: Gardner Richard J. , Hug Daniel , Weil Wolfgang
Published: October 2013

An investigation is launched into the fundamental characteristics of operations on and between sets, with a focus on compact convex sets and star sets (compact sets star-shaped with respect to the origin) in

n

-dimensional Euclidean space

\mathbb R^n

. It is proved that if

n\ge 2

, with three trivial exceptions, an operation between origin-symmetric compact convex sets is continuous in the Hausdorff metric,

\operatorname{GL}(n)

covariant, and associative if and only if it is

L_p

addition for some

1\le p\le\infty

. It is also demonstrated that if

n\ge 2

, an operation

*

between compact convex sets is continuous in the Hausdorff metric,

\operatorname{GL}(n)

covariant, and has the identity property (i.e.,

K*\{o\}=K=\{o\}*K

for all compact convex sets

K

, where

o

denotes the origin) if and only if it is Minkowski addition. Some analogous results for operations between star sets are obtained. Various characterizations are given of operations that are projection covariant, meaning that the operation can take place before or after projection onto subspaces, with the same effect.

Several other new lines of investigation are followed. A relatively little-known but seminal operation called

M

-addition is generalized and systematically studied for the first time. Geometric-analytic formulas that characterize continuous and

\operatorname{GL}(n)

-covariant operations between compact convex sets in terms of

M

-addition are established. It is shown that if

n\ge 2

, an

o

-symmetrization of compact convex sets (i.e., a map from the compact convex sets to the origin-symmetric compact convex sets) is continuous in the Hausdorff metric,

\operatorname{GL}(n)

covariant, and translation invariant if and only if it is of the form

\lambda DK

for some

\lambda\ge 0

, where

DK=K+(-K)

is the difference body of

K

. The term “polynomial volume” is introduced for the property of operations

*

between compact convex or star sets that the volume of

rK*sL

,

r,s\ge 0

, is a polynomial in the variables

r

and

s

. It is proved that if

n\ge 2

, with three trivial exceptions, an operation between origin-symmetric compact convex sets is continuous in the Hausdorff metric,

\operatorname{GL}(n)

covariant, associative, and has polynomial volume if and only if it is Minkowski addition.
The under‐ice microbiome of seasonally frozen lakes
Authors: Bertilsson Stefan , Burgin Amy , Carey Cayelan C. , Fey Samuel B. , Grossart Hans-Peter , Grubisic Lorena M. , Jones Ian D. , Kirillin Georgiy , Lennon Jay T. , Shade Ashley , Smyth Robyn L.
Published: October 2013

Compared to the well‐studied open water of the “growing” season, under‐ice conditions in lakes are characterized by low and rather constant temperature, slow water movements, limited light availability, and reduced exchange with the surrounding landscape. These conditions interact with ice‐cover duration to shape microbial processes in temperate lakes and ultimately influence the phenology of community and ecosystem processes. We review the current knowledge on microorganisms in seasonally frozen lakes. Specifically, we highlight how under‐ice conditions alter lake physics and the ways that this can affect the distribution and metabolism of auto‐ and heterotrophic microorganisms. We identify functional traits that we hypothesize are important for understanding under‐ice dynamics and discuss how these traits influence species interactions. As ice coverage duration has already been seen to reduce as air temperatures have warmed, the dynamics of the under‐ice microbiome are important for understanding and predicting the dynamics and functioning of seasonally frozen lakes in the near future.
Copper requirements of the ammonia‐oxidizing archaeon Nitrosopumilus maritimus SCM1 and implications for nitrification in the marine environment
Authors: Amin Shady A. , Moffett James W. , Martens-Habbena Willm , Jacquot Jeremy E. , Han Yang , Devol Allan , Ingalls Anitra E. , Stahl David A. , Armbrust E. Virginia
Published: October 2013

Ammonia oxidizing archaea (AOA) have recently been recognized as the primary nitrifiers in the marine environment; they thus play an important role in the nitrogen cycle. Available genome sequences of AOA indicate that numerous Cu‐dependent enzymes are essential for both ammonia oxidation and electron transfer, suggesting a particularly high requirement for copper. However, our knowledge of the copper requirements of AOA and their response to copper limitation in the ocean is nonexistent. Here, we examine the copper requirements of the chemolithoautotrophic AOA Candidatus Nitrosopumilus maritimus SCM1 using a combination of the metal chelators ethylenediaminetetraacetic acid and 1,4,8,11‐tetraazacyclotetradecane‐1,4,8,11‐tetraacetic acid and show that ammonia oxidation is limited at free cupric ion concentrations < 10−12.7 mol L−1, which are higher than concentrations frequently reported for many coastal and oceanic regimes. Prolonged exposure of cells to copper starvation for up to 6 d had no effect on the recovery of ammonia oxidation by N. maritimus. In addition, we present evidence that N. maritimus does not produce a copper‐binding ligand (chalkophore) under copper limitation and therefore probably relies mainly on acquisition of copper ions from surrounding media. Copper limitation may be an important constraint on archaeal ammonia oxidation throughout the marine environment.
Iron, phosphorus, and nitrogen supply ratios define the biogeography of nitrogen fixation
Authors: Ward Ben A. , Dutkiewicz Stephanie , Moore C. Mark , Follows Michael J.
Published: October 2013

We present a unified conceptual framework describing the competition between diazotrophs and non‐nitrogen‐fixing marine plankton and their interaction with three essential nutrient elements: nitrogen (N), phosphorus (P), and iron (Fe). The theory explains the global biogeography of diazotrophs and the observed large‐scale variations in surface ocean nutrient concentrations. The ratios in which N, P, and Fe are delivered to the surface ocean, relative to the demands of the phytoplankton community, define several biogeochemical provinces in terms of the limiting nutrients and the presence or absence of diazotrophs. Nutrient supply ratios provided by a global ecosystem model support the theoretical view that diazotroph biogeography is dominated by the Fe : N supply ratio, with the P : N supply ratio taking an important secondary role. The theory yields robust predictions for which strong empirical support is found in global observations of surface nutrient concentrations and diazotroph abundance.
Goldman revisited: Faster‐growing phytoplankton has lower N : P and lower stoichiometric flexibility
Authors: Hillebrand Helmut , Steinert Georg , Boersma Maarten , Malzahn Arne , Meunier Cédric Léo , Plum Christoph , Ptacnik Robert
Published: October 2013

In their seminal paper, Goldman et al. suggested that phytoplankton close to maximum growth rate attains a restricted optimal N : P ratio close to the Redfield ratio of molar N : P = 16. Recently, the presence of such a global attractor for optimal phytoplankton stoichiometry has been questioned in models and empirical analyses. As the chemical composition of phytoplankton is of major importance for our understanding of global elemental cycles and biogeochemical transformations, we assembled 55 data sets of phytoplankton growth rate and biomass N : P ratios in a meta‐analysis testing (1) whether phytoplankton N : P converges at high growth rates, (2) whether N : P ratios scale with growth rate, and (3) whether the optimal N : P ratios achieved at highest growth rates reflect organism traits or environmental conditions. Across systems and species, phytoplankton N : P decreased with increasing growth rate and at the same time showed decreasing variance, i.e., fast‐growing phytoplankton is more P rich and has a more confined elemental composition. Optimal N : P increased with increasing N : P of available nutrients, i.e., with increasing P limitation. Other differences were rare, except cyanobacteria showed higher optimal N : P than diatoms. Understanding the role of phytoplankton in biogeochemical transformation requires modeling approaches that are stoichiometrically flexible to reflect the dynamics of growth and nutrient supply in primary producers.
The Association between Use of a Clinical Decision Support Tool and Adherence to Monitoring for Medication-Laboratory Guidelines in the Ambulatory Setting
Authors: Lau B. , Overby C. L. , Wirtz H. S. , Devine E. B.
Published: October 2013

Background: Stage 2 Meaningful Use criteria require the use of clinical decision support systems (CDSS) on high priority health conditions to improve clinical quality measures. Although CDSS hold great promise, implementation has been fraught with challenges, evidence of their impact is mixed, and the optimal method of content delivery is unknown.

Objective: The authors investigated whether implementation of a simple clinical decision support (CDS) tool was associated with improved prescriber adherence to national medication-laboratory monitoring guidelines for safety (hepatic function, renal function, myalgias/rhabdomyolysis) and intermediate outcomes for antidiabetic (Hemoglobin A1c; HbA1c) and antihyperlipidemic (low density lipoprotein; LDL) medications prescribed within a diabetes registry.

Methods: This was a retrospective observational study conducted in three phases of CDS implementation (2008–2009): pre-, transition-, and post-Prescriptions evaluated were ordered from an electronic health record within a multispecialty medical group. Adherence was evaluated within and without applying guideline-imposed time constraints.

Results: Forty-thousand prescriptions were ordered over three timeframes. For hepatic and renal function, the proportion of prescriptions for which labs were monitored at any time increased from 52% to 65% (p<0.001); those that met time guidelines, from 14% to 21% (p<0.001). Only 6% of required labs were drawn to monitor for myalgias/rhabdomyolysis, regardless of timeframe. Over 90% of safety labs were within normal limits. The proportion of labs monitored at any time for LDL increased from 56% to 64% (p<0.001); those that met time guidelines from 11% to 17% (p<0.001). The proportion of labs monitored at any time for HbA1c remained the same (72%); those that met time guidelines decreased from 45% to 41% (p<0.001).

Conclusions: A simple CDS tool may be associated with improved adherence to guidelines. Efforts are needed to confirm findings and improve the timeliness of monitoring; investigations to optimize alerts should be ongoing.

Citation: Lau B, Overby CL, Wirtz HS, Devine EB. The association between use of a clinical decision support tool and adherence to monitoring for medication-laboratory guidelines in the ambulatory setting. Appl ClinInf 2013; 4: 476–498

http://dx.doi.org/10.4338/ACI-2013-06-RA-0041
Prenatal Detection of Fetal Anomalies at the 11- to 13-Week Scan—Part I: Brain, Face and Neck
Authors: Illescas Tamara , Sepulveda Waldo , Adiego Begona , Martinez-Ten Pilar
Published: October 2013

In the last 20 years, the role of first-trimester ultrasound screening has expanded from individual calculation of the risk of aneuploidy through measurement of the nuchal translucency to a powerful technique to evaluate important aspects of the fetal anatomy. Traditionally, the full anatomy scan for detection of structural anomalies has been performed in the second trimester of pregnancy. However, with the implementation of the first-trimester scan at 11 to 13 weeks of gestation many of the structural anomalies traditionally detected in the second trimester can now be identified earlier in pregnancy. In the first part of this review we discuss the main ultrasound findings that may facilitate the prenatal detection of fetal brain, face and neck abnormalities in the first trimester of pregnancy.

How to cite this article

Sepulveda W, Illescas T, Adiego B, Martinez-Ten P. Prenatal Detection of Fetal Anomalies at the 11- to 13-Week Scan—Part I: Brain, Face and Neck. Donald School J Ultrasound Obstet Gynecol 2013;7(4):359-368.
Current Role of 3D/4D Sonography in Obstetrics and Gynecology
Authors: Pashaj Sonila , Merz Eberhard
Published: October 2013

Modern 3D/4D sonography provides a routine method not only for storing single image planes as in 2D ultrasound but also for storing complete sets of volume data in the computer memory. Once acquisition is completed, all volumes can be accessed from the memory and normal and abnormal findings in both obstetrics and gynecology can be demonstrated in different display modes. Furthermore digital storage of volumes permits virtual examinations by reloading of volumes and navigating through them in the absence of the patient.

This review article would like to give an illustration of the latest technologies in 3D/4D ultrasound in obstetrics and gynecology.

How to cite this article

Merz E, Pashaj S. Current Role of 3D/ 4D Sonography in Obstetrics and Gynecology. Donald School J Ultrasound Obstet Gynecol 2013;7(4):400-408.
Improving our Knowledge in Twins: The Role of Ductus Venosus in the First Trimester
Authors: Montenegro Nuno , Matias Alexandra
Published: October 2013

Ductus venosus (DV) is a tiny vessel with a central role in fetal circulation both in singletons and multiples. In the present review we detail the contribution of DV evaluation in twin pregnancies in the first trimeter of pregnancy. The higher prevalence of abnormal A-wave in fetuses with abnormal karyotype and/or cardiac defects made DV evaluation a useful marker for the screening of chromosomal abnormalities and fetal cardiac anomalies. In dichorionic (DC) pregnancies, DV blood flow assessment reproduces the role of NT in the screening for aneuploidies, just as in singleton pregnancies. In monochorionic (MC) twin pregnancies, the Doppler assessment of DV blood flow improves the detection of those at higher risk of developing twin-to-twin transfusion syndrome or growth discrepancy later in pregnancy. As for singletons, DV should be systematically evaluated in all first trimester scans for a more performant screening in multiples.

How to cite this article

Matias A, Montenegro N. Improving our Knowledge in Twins: The Role of Ductus Venosus in the First Trimester. Donald School J Ultrasound Obstet Gynecol 2013;7(4):409-414.
Ultrasound Assessment and Surgical Treatment of Twin-Twin Transfusion Syndrome
Authors: Kontopoulos Eftichia V , Quintero Rubén A
Published: October 2013

The ultrasound diagnosis, management and treatment of twintwin transfusion syndrome (TTTS) have had a remarkable number of positive developments in the last 20 years. Together, they have resulted in TTTS being the most common condition seen and treated in fetal therapy centers today. This chapter discusses the basic ultrasound assessment of TTTS patients in a step-by-step fashion, to provide a structure to the sonographic examination. This includes review of the diagnostic criteria, the sonographic assessment of disease severity and preoperative ultrasound assessment. The chapter also reviews the rationale for, as well as the fundamental laser technique and its variations, including the nonselective technique, selective laser photocoagulation of communicating vessels (SLPCV), sequential selective laser photocoagulation of the communicating vessels (SQLPCV) and the ‘Solomon’ technique, and provides potential explanations for the outcome differences of each technique. Future developments in terms of surgical technique and long-term outcome studies are also discussed.

How to cite this article

Quintero RA, Kontopoulos EV. Ultrasound Assessment and Surgical Treatment of Twin-Twin Transfusion Syndrome. Donald School J Ultrasound Obstet Gynecol 2013;7(4):415-425.
Diagnostic Prenatal Invasive Procedures in Obstetrics
Authors: Angelica Zoppi Maria
Published: October 2013

In 1977, we performed in Cagliari the first invasive prenatal diagnosis for beta-thalassemia in Europe, using fetal blood sampling by placentacentesis and chain globins analysis at 20th week of gestation. Since then we have performed more than 8,000 fetal diagnoses for beta-thalassemia using placentacentesis, fetoscopy, cordocentesis, cardiocentesis, amniocentesis, transcervical-chorionic villus sampling (TC-CVS), transabdominal (TA-CVS) and preimplantation genetic diagnosis (PGD) by embryo biopsy.

Since 1986 we have been using for the beta-thalassemia and other single gene diseases only TA-CVS and PGD and DNA polymerase chain reaction (PCR) analysis.

For karyotype we have been using mostly TA-CVS and amniocentesis and traditional cytogenetic analysis, in several cases also fluorescent in situ hybridization (FISH) and comparative genomic hybridization (CGH) array.

How to cite this article

Monni G, Zoppi MA, Iuculano A. Diagnostic Prenatal Invasive Procedures in Obstetrics. Donald School J Ultrasound Obstet Gynecol 2013;7(4):426-428.