bluuebunny/crossref_metadata_2025 huggingface dataset:
Sanfilippo B in an elderly female psychiatric patient: a rare but relevant diagnosis in presenile dementia
Authors: Verhoeven W. M. A. , Csepán R. , Marcelis C. L. M. , Lefeber D. J. , Egger J. I. M. , Tuinier S.
Published: December 2009

Verhoeven WMA, Csepán R, Marcelis CLM, Lefeber DJ, Egger JIM, Tuinier S. Sanfilippo B in an elderly female psychiatric patient: a rare but relevant diagnosis in presenile dementia.

Objective:  Sanfilippo B is a rare autosomal recessive mucopolysaccharidosis (MPS IIIB) caused by a deficiency of N‐acetyl‐α‐D‐glucosaminidase (NAGLU).

Method:  A mild mentally retarded elderly female patient is described with a slowly progressive dementia who had given birth to a daughter who developed normally.

Results:  Metabolic screening revealed an enhanced concentration of heparan sulfate in urine. Enzymatic assay demonstrated deficiency of N‐acetyl‐α‐D‐glucosaminidase. Mutations in the NAGLU gene were found. One mentally retarded and hospitalized elder brother was also found to have MPS IIIB, whereas a second brother, who had died earlier, is suspected to have had the same metabolic disorder. Prior to the development of dementia, both the patient and her brother showed autistic like features, signs of ideomotor apraxia and weakness in verbal comprehension.

Conclusion:  Screening for metabolic disorders, in particular MPSes, should always be considered in patients with a history of mental deficit and dementia or progressive functional decline.
Age at onset in 3014 Sardinian bipolar and major depressive disorder patients
Authors: Tondo L. , Lepri B. , Cruz N. , Baldessarini R. J.
Published: December 2009

Tondo L, Lepri B, Cruz N, Baldessarini RJ. Age at onset in 3014 Sardinian bipolar and major depressive disorder patients.

Objective:  To test if onset age in major affective illnesses is younger in bipolar disorder (BPD) than unipolar‐major depressive disorder (UP‐MDD), and is a useful measure.

Method:  We evaluated onset‐age for DSM‐IV‐TR major illnesses in 3014 adults (18.5% BP‐I, 12.5% BP‐II, 69.0% UP‐MDD; 64% women) at a mood‐disorders center.

Results:  Median and interquartile range (IQR) onset‐age ranked: BP‐I = 24 (19–32) < BP‐II = 29 (20–40) < UP‐MDD = 32 (23–47) years (P < 0.0001), and has remained stable since the 1970s. In BP‐I patients, onset was latest for hypomania, and depression presented earlier than in BP‐II or UP‐MDD cases. Factors associated with younger onset included: i) being unmarried, ii) more education, iii) BPD‐diagnosis, iv) family‐history, v) being employed, vi) ever‐suicidal, vii) substance‐abuse and viii) ever‐hospitalized. Onset‐age distinguished BP‐I from UP‐MDD depressive onsets with weak sensitivity and specificity.

Conclusion:  Onset age was younger among BPD than MDD patients, and very early onset may distinguish BPD vs. UP‐MDD with depressive‐onset.
Myelodysplastic syndrome in elderly patients: correlation of CBC with cytogenetic and FISH analysis
Authors: CODISPOTI K.‐E. T. , DEPALMA L.
Published: December 2009

Unexplained anemia in the elderly could represent myelodysplastic syndrome (MDS). We assessed the utility of using a fluorescence in situ hybridization (FISH) panel for common chromosomal abnormalities seen in MDS. A total of 101 elderly outpatients with anemia of unknown etiology were evaluated. Complete blood count, bone marrow biopsy, conventional cytogenetic analysis (CC), and FISH panel were reviewed. A total of 21 (21%) of the 101 patients had MDS. A combination of CC and FISH identified chromosomal abnormalities in 17 (81%) of the patients with MDS. The remaining 4 (19%) were diagnosed with MDS based solely on morphologic criteria. Except in two cases, FISH did not reveal abnormalities not already detected by CC. Furthermore, MDS patients infrequently had isolated anemia (14%) as opposed to those without MDS (75%). A MDS FISH panel is not more sensitive than CC in elderly outpatients with unexplained anemia. MDS is more likely if in addition to anemia, leukopenia and/or thrombocytopenia are also present.
Overcoming Short‐Termism: Mental Time Travel, Delayed Gratification and How Not to Discount the Future
Authors: Irving Kym
Published: December 2009

Short‐termism has been identified as a characteristic of individuals, companies, stock markets, governance structures and policies, and has been linked to inadequate saving for retirement, reduced investment returns, greater market instability and destruction of long‐term value. As a construct, short‐termism is complex and multidimensional. Accordingly, this paper draws upon current theory and research from a range of fields including behavioural economics, psychology and the cognitive sciences to uncover both explanations of the phenomenon and implications for countering an overly short‐term focus. Possible strategies for achieving the latter are discussed.
Discount Rates in Disarray: Evidence on Flawed Goodwill Impairment Testing
Authors: Lonergan Wayne
Published: December 2009

The onset of the Global Financial Crisis (GFC) will focus even more attention on the inadequacies in impairment testing by reporting entities. However, experience with the corporate sector, even before the GFC, indicated that there were widespread problems in practice with impairment testing. The article by Carlin and Finch is therefore both timely and particularly relevant to the current capital markets.
The Employment Landscape for Accounting Graduates and Work Experience Relevance
Authors: Cheng Mandy , Kang Helen , Roebuck Peter , Simnett Roger
Published: December 2009

This study outlines the results of a survey undertaken at an Australian university in 2007 and examines the factors that are associated with an undergraduate accounting student obtaining a job offer. Undertaking relevant part‐time work, academic performance and social (extra‐curricular) activities are significant factors leading to job offers prior to graduation. Our study also identifies a high level of part‐time work currently undertaken by full‐time students, confirming the trend identified in other studies. Interestingly, this high level of part‐time work was not found to negatively affect students’ academic performance.
Discount Rates in Disarray: Evidence on Flawed Goodwill Impairment Testing
Authors: Gallery Gerry
Published: December 2009

Carlin and Finch, this issue, compare goodwill impairment discount rates used by a sample of large Australian firms with ‘independently’ generated discount rates. Their objective is to empirically determine whether managers opportunistically select goodwill discount rates subsequent to the 2005 introduction of International Financial Reporting Standards (IFRS) in Australia. This is a worthwhile objective given that IFRS introduced an impairment regime, and within this regime, discount rate selection plays a key role in goodwill valuation decisions. It is also timely to consider the goodwill valuation issue. Following the recent downturn in the economy, there is a high probability that many firms will be forced to write down impaired goodwill arising from boom period acquisitions. Hence, evidence of bias in rate selection is likely to be of major concern to investors, policymakers and corporate regulators. Carlin and Finch claim their findings provide evidence of such bias. In this commentary I review the validity of their claims.
Effects of exercise on muscle glycogen synthesis signalling and enzyme activities in pigs carrying the PRKAG3 mutation
Authors: Granlund Anna , Kotova Olga , Benziane Boubacar , Galuska Dana , Jensen‐Waern Marianne , Chibalin Alexander V. , Essén‐Gustavsson Birgitta
Published: December 2009

The dominant RN− mutation in pigs results in excessive glycogen storage in skeletal muscle. The mutation is situated in the PRKAG3 gene, which encodes a muscle‐specific isoform of the AMP‐activated protein kinase (AMPK) γ3 subunit. AMPK is an important regulator of carbohydrate and fat metabolism in mammalian cells. The aim of the present study was to examine the effect of exercise on glycogen synthesis signalling pathways in muscle and to study enzyme activities of importance in carbohydrate metabolism in pigs with or without the PRKAG3 mutation. Glycogen content, metabolic enzyme activities and expression or phosphorylation of signalling proteins were analysed in skeletal muscle specimens obtained at rest, after a single treadmill exercise bout and after 3 h recovery. The PRKAG3 mutation carriers had higher glycogen content, a tendency for lower expression of AMPK (P < 0.07) and higher hexokinase and phosphorylase activities, whereas citrate synthase, 3‐hydroxyacyl‐CoA dehydrogenase and glycogen synthase activities did not differ between genotypes. Carriers and non‐carriers of the RN− mutation showed a similar degradation of glycogen after exercise, whereas the rate of resynthesis was faster in the carriers. Acute exercise stimulated Akt phosphorylation on Ser473 in both genotypes, and the effect was greater in the carriers than in the non‐carriers. Acute exercise also stimulated phosphorylation of Akt substrate of 160 kDA and Glycogen synthase kinase 3 in the carriers and GSK3α in the non‐carriers. In conclusion, the increased rate of glycogen synthesis following exercise in pigs carrying the PRKAG3 mutation correlates with an increased signalling response of Akt and its substrate, AS160, and a higher activity of hexokinase, indicating an increased glucose influx and phosphorylation of glucose, directed towards glycogen synthesis.
Synergistic Antimicrobial Activities of Folic Acid Antagonists and Nucleoside Analogs
Authors: Zander Johannes , Besier Silke , Ackermann Hanns , Wichelhaus Thomas A.
Published: December 2009

The antimicrobial activities of folic acid antagonists are supposed to be antagonized by elevated extracellular thymidine concentrations in damaged host tissues. Therefore, this study was aimed at screening for nucleoside analogs that impair bacterial thymidine utilization and analyzing the combined antimicrobial activities of nucleoside analogs and folic acid antagonists in the presence of thymidine. Our screening results revealed that different nucleoside analogs, in particular halogenated derivatives of 2′-deoxyuridine, substantially impaired the bacterial utilization of extracellular thymidine in
Staphylococcus aureus
. Time-kill methods showed that 5-iodo-2′-deoxyuridine enhanced the extent of killing of trimethoprim-sulfamethoxazole (SXT) at 24 h against
S. aureus
in the presence of thymidine (200 μg/liter). While SXT (40 mg/liter) alone did not kill bacteria in the presence of thymidine, its combination with the nucleoside analog at a concentration of 8 μmol/liter showed a bactericidal effect. Moreover, 5-iodo-2′-deoxyuridine combined with SXT in the presence of thymidine showed a broad spectrum of activity against several Gram-positive and Gram-negative bacteria. In conclusion, these data provide evidence that the
in vitro
antimicrobial activity of SXT in the presence of thymidine can be significantly improved by combination with a nucleoside analog.
Comparison of Anidulafungin MICs Determined by the Clinical and Laboratory Standards Institute Broth Microdilution Method (M27-A3 Document) and Etest for
Candida
Species Isolates
Authors: Espinel-Ingroff Ana , Canton E. , Peman J. , Martín-Mazuelo E.
Published: December 2009

Anidulafungin Etest and CLSI MICs were compared for 143
Candida
sp. isolates to assess essential (within 2 log
2
dilutions) and categorical agreements (according to three susceptibility breakpoints). Based on agreement percentages, our data indicated that Etest is not suitable to test anidulafungin against
Candida parapsilosis
and
C. guilliermondii
(54.4 to 82.4% essential and categorical agreements) but is more suitable for
C. albicans
,
C. glabrata
,
C. krusei
, and
C. tropicalis
(87.9 to 100% categorical agreement).
Detection of Molecular Markers of Drug Resistance in 2009 Pandemic Influenza A (H1N1) Viruses by Pyrosequencing
Authors: Deyde Varough M. , Sheu Tiffany G. , Trujillo A. Angelica , Okomo-Adhiambo Margaret , Garten Rebecca , Klimov Alexander I. , Gubareva Larisa V.
Published: December 2009

The M2 blockers amantadine and rimantadine and the neuraminidase (NA) inhibitors (NAIs) oseltamivir and zanamivir are approved by the FDA for use for the control of influenza A virus infections. The 2009 pandemic influenza A (H1N1) viruses (H1N1pdm) are reassortants that acquired M and NA gene segments from a Eurasian adamantane-resistant swine influenza virus. NAI resistance in the H1N1pdm viruses has been rare, and its occurrence is mainly limited to oseltamivir-exposed patients. The pyrosequencing assay has been proven to be a useful tool in surveillance for drug resistance in seasonal influenza A viruses. We provide a protocol which allows the detection of adamantane resistance markers as well as the I43T change, which is unique to the H1N1pdm M2 protein. The protocol also allows the detection of changes at residues V116, I117, E119, Q136, K150, D151, D199, I223, H275, and N295 in the NA, known to alter NAI drug susceptibility. We report on the detection of the first cases of the oseltamivir resistance-conferring mutation H275Y and the I223V change in viruses from the United States using the approach described in this study. Moreover, the assay permits the quick identification of the major NA group (V106/N248, I106/D248, or I106/N248) to which a pandemic virus belongs. Pyrosequencing is well suited for the detection of drug resistance markers and signature mutations in the M and NA gene segments of the pandemic H1N1 influenza viruses.
Antimalarial Asexual Stage-Specific and Gametocytocidal Activities of HIV Protease Inhibitors
Authors: Peatey Christopher L. , Andrews Katherine T. , Eickel Nina , MacDonald Timothy , Butterworth Alice S. , Trenholme Katharine R. , Gardiner Donald L. , McCarthy James S. , Skinner-Adams Tina S.
Published: December 2009

The stage-specific antimalarial activities of a panel of antiretroviral protease inhibitors (PIs), including two nonpeptidic PIs (tipranavir and darunavir), were tested
in vitro
against
Plasmodium falciparum
. While darunavir demonstrated limited antimalarial activity (effective concentration [EC
50
], >50 μM), tipranavir was active at clinically relevant concentrations (EC
50
, 12 to 21 μM). Saquinavir, lopinavir, and tipranavir preferentially inhibited the growth of mature asexual-stage parasites (24 h postinvasion). While all of the PIs tested inhibited gametocytogenesis, tipranavir was the only one to exhibit gametocytocidal activity.
Meningococcal Porin PorB Prevents Cellular Apoptosis in a Toll-Like Receptor 2- and NF-κB-Independent Manner
Authors: Massari Paola , Gunawardana Jay , Liu Xiuping , Wetzler Lee M.
Published: December 2009

Meningococcal porin PorB is an inhibitor of apoptosis induced via the intrinsic pathway in various cell types. This effect is attributed to prevention of mitochondrial depolarization and of subsequent release of proapoptotic mitochondrial factors. To determine whether apoptosis is globally inhibited by PorB, we compared the intrinsic and extrinsic pathways in HeLa cells. Interestingly, PorB does not prevent extrinsic apoptosis induced by tumor necrosis factor alpha plus cycloheximide, suggesting a unique mitochondrial pathway specificity. Several intracellular factors regulated by NF-κB, including members of the Bcl-2 family and of the inhibitor of apoptosis (IAP) family, play major roles in controlling apoptosis, and some of them are thought to contribute to the antiapoptotic effect of the gonococcal porin, PIB. However, most of the members of the Bcl-2 family and the IAP family are not induced by meningococcal PorB in HeLa cells, with the exception of Bfl-1/A1. Interestingly, PorB does not induce NF-κB activation in HeLa cells, likely due to a lack of Toll-like receptor 2 (TLR2) expression in these cells. Bfl-1/A1 expression is also regulated by CBF1, a nuclear component of the Notch signaling pathway, independent of NF-κB activation. Since HeLa cells are protected by PorB from intrinsic apoptosis events, regardless of TLR2 and NF-κB expression, the possibility of a contribution of alternative signaling pathways to this effect cannot be excluded. In this paper, we describe an initial dissection of the cascade of cellular events involved in the antiapoptotic effect of PorB in the absence of TLR2.
Influence of Mannan and Glucan on Complement Activation and C3 Binding byCandida albicans
Authors: Boxx Gayle M. , Kozel Thomas R. , Nishiya Casey T. , Zhang Mason X.
Published: December 2009

The complement system is important for host resistance to hematogenously disseminated candidiasis. However, modulation of complement activation by cell wall components ofCandida albicanshas not been characterized. Although intact yeast display mannan on the surface, glucan, typically located in the interior, becomes exposed duringC. albicansinfection. We show here the distinct effects of mannan and glucan on complement activation and opsonophagocytosis. Previous studies showed that intact cells are resistant to initiation of complement activation through the alternative pathway, and antimannan antibody reverses this resistance via an Fc-independent mechanism. The present study shows that this mannan-dependent resistance can be overcome by periodate-borohydride conversion of mannose polysaccharides to polyalcohols; cells treated with periodate-borohydride initiate the alternative pathway without the need for antibody. These observations identify an inhibitory role for intact mannan in complement activation. Next, removal of the surface-displayed mannan by acid treatment of periodate-borohydride cells exposes glucan. Glucan-displaying cells or purified β-glucan initiate the alternative pathway when incubated with the purified proteins of the alternative pathway alone, suggesting thatC. albicansglucan is a natural activator of the alternative pathway. Finally, ingestion of mannan-displaying cells by human neutrophils requires anti-mannan antibody, whereas ingestion of glucan-displaying cells requires complement. These results demonstrate a contrasting requirement of natural antibody and complement for opsonophagocytosis ofC. albicanscells displaying mannan or glucan. Thus, differential surface expression of mannan and glucan may influence recognition ofC. albicansby the complement system.
The
Pseudomonas aeruginosa
Magnesium Transporter MgtE Inhibits Transcription of the Type III Secretion System
Authors: Anderson Gregory G. , Yahr Timothy L. , Lovewell Rustin R. , O'Toole George A.
Published: December 2009

Pseudomonas aeruginosa
is an opportunistic pathogen that causes life-long pneumonia in individuals with cystic fibrosis (CF). These long-term infections are maintained by bacterial biofilm formation in the CF lung. We have recently developed a model of
P. aeruginosa
biofilm formation on cultured CF airway epithelial cells. Using this model, we discovered that mutation of a putative magnesium transporter gene, called
mgtE
, led to increased cytotoxicity of
P. aeruginosa
toward epithelial cells. This altered toxicity appeared to be dependent upon expression of the type III secretion system (T3SS). In this study, we found that mutation of
mgtE
results in increased T3SS gene transcription. Through epistasis analyses, we discovered that MgtE influences the ExsE-ExsC-ExsD-ExsA gene regulatory system of T3SS by either directly or indirectly inhibiting ExsA activity. While variations in calcium levels modulate T3SS gene expression in
P. aeruginosa
, we found that addition of exogenous magnesium did not inhibit T3SS activity. Furthermore,
mgtE
variants that were defective for magnesium transport could still complement the cytotoxicity effect. Thus, the magnesium transport function of MgtE does not fully explain the regulatory effects of MgtE on cytotoxicity. Overall, our results indicate that MgtE modulates expression of T3SS genes.
Molecular Characterization of the Dot/Icm-Translocated AnkH and AnkJ Eukaryotic-Like Effectors ofLegionella pneumophila
Authors: Habyarimana Fabien , Price Chris T. , Santic Marina , Al-Khodor Souhaila , Kwaik Yousef Abu
Published: December 2009

Although most Dot/Icm-translocated effectors ofLegionella pneumophilaare not required for intracellular proliferation, the eukaryotic-like ankyrin effectors, AnkH and AnkJ are required for intracellular proliferation. In this report, we show that the IcmSW chaperones are essential for translocation of AnkJ but not AnkH. The 10 C-terminal residues and the ANK domains of AnkH and AnkJ are required for translocation. Our data indicate that the two ANK domains of AnkH are critical domains required for the function of the effector in intracellular replication ofL. pneumophila. TheankHandankJmutants are severely defective in intrapulmonary proliferation in mice. Expression of AnkH and AnkJ fusions within HEK293 cells show a punctuate distribution in the cytosol but no association with endocytic vesicles, the Golgi apparatus or the endoplasmic reticulum. Interestingly, the defect in intracellular proliferation of theankHorankJmutants is rescued in HEK293 cells expressing the respective protein. We conclude that AnkH and AnkJ are effectors translocated by the Dot/Icm system by distinct mechanisms and modulate distinct cytosolic processes in the host cell.
Phosphoglucomutase ofYersinia pestisIs Required for Autoaggregation and Polymyxin B Resistance
Authors: Felek Suleyman , Muszyński Artur , Carlson Russell W. , Tsang Tiffany M. , Hinnebusch B. Joseph , Krukonis Eric S.
Published: December 2009

Yersinia pestis, the causative agent of plague, autoaggregates within a few minutes of cessation of shaking when grown at 28°C. To identify the autoaggregation factor ofY. pestis, we performedmariner-based transposon mutagenesis. Autoaggregation-defective mutants from three different pools were identified, each with a transposon insertion at a different position within the gene encoding phosphoglucomutase (pgmA;y1258). Targeted deletion ofpgmAinY. pestisKIM5 also resulted in loss of autoaggregation. Given the previously defined role for phosphoglucomutase in antimicrobial peptide resistance in other organisms, we tested the KIM5 ΔpgmAmutant for antimicrobial peptide sensitivity. The ΔpgmAmutant displayed >1,000-fold increased sensitivity to polymyxin B compared to the parentalY. pestisstrain, KIM5. This sensitivity is not due to changes in lipopolysaccharide (LPS) since the LPSs from bothY. pestisKIM5 and the ΔpgmAmutant are identical based on a comparison of their structures by mass spectrometry (MS), tandem MS, and nuclear magnetic resonance analyses. Furthermore, the ability of polymyxin B to neutralize LPS toxicity was identical for LPS purified from both KIM5 and the ΔpgmAmutant. Our results indicate that increased polymyxin B sensitivity of the ΔpgmAmutant is due to changes in surface structures other than LPS. Experiments with mice via the intravenous and intranasal routes did not demonstrate any virulence defect for the ΔpgmAmutant, nor was flea colonization or blockage affected. Our findings suggest that the activity of PgmA results in modification and/or elaboration of a surface component ofY. pestisresponsible for autoaggregation and polymyxin B resistance.
Efficacy of
MedMyst
: an Internet Teaching Tool for Middle School Microbiology
Authors: MILLER LESLIE M. , MORENO JANETTE , ESTRERA VICKY , LANE DAVID
Published: December 2009

Can web-based technology be used to effectively introduce or reinforce aspects of microbiology to middle school students? This central hypothesis examines whether brief exposure to a web adventure format containing virtual lab experiments and computer games within an engaging story line can impact student learning. An episodic adventure series,
MedMyst
(
http://medmyst.rice.edu
), focuses on infectious diseases and the microbes that cause them. The website is not intended to replace classroom instruction, but rather to engage students in problem-solving activities not likely to be encountered elsewhere. It also provides scientists with a resource to introduce microbiology to adolescent audiences through outreach activities. In the online adventure, the player (student) enters a futuristic world in which he or she becomes a “Reconstructor,” a member of an elite team charged with preventing the spread of infectious disease. The series consists of three “missions,” each lasting approximately 30 to 40 minutes and designed to address a limited set of learning objectives. Middle school students participated in the creation of the characters and the stylized design through focus groups. Classroom teachers oversaw the alignment of the web adventure objectives with the National Science Content Standards. Scientists and clinicians reviewed the web adventure for content and accuracy. A field test involving over 700 students from nine different schools assessed the knowledge gains attributable to playing
MedMyst
. Gain scores from pretest to posttest indicated that middle school students retained important information by interacting with the online material for as little as 30 minutes per adventure; however, gains for high school students were less persuasive, perhaps indicating a different learning tool or content is required for this age audience.
Teaching Phagocytosis Using Flow Cytometry
Authors: BOOTHBY JOHN T. , KIBLER RUTHANN , RECH SABINE , HICKS ROBERT
Published: December 2009

Investigative microbiology on protists in a basic teaching laboratory environment is limited by student skill level, ease of microbial culture and manipulation, instrumentation, and time. The flow cytometer is gaining use as a mainstream instrument in research and clinical laboratories, but has had minimal application in teaching laboratories. Although the cost of a flow cytometer is currently prohibitive for many microbiology teaching environments and the number of trained instructors and teaching materials is limited, in many ways the flow cytometer is an ideal instrument for teaching basic microbiology. We report here on a laboratory module to study phagocytosis in
Tetrahymena
sp. using flow cytometry in a basic microbiology teaching laboratory. Students and instructors found the flow cytometry data analysis program, Paint-AGate
PRO-TM
, to be very intuitive and easy to learn within a short period of time. Assessment of student learning about
Tetrahymena
sp., phagocytosis, flow cytometry, and investigative microbiology using an inquiry-based format demonstrated an overall positive response from students.
A new basal hadrosauriform dinosaur (Ornithischia: Iguanodontia) from the Early Cretaceous of northwestern China
Authors: You Hai-Lu , Li Da-Qing
Published: December 2009

A new hadrosauriform dinosaur, Jintasaurus meniscus gen. et sp. nov., is reported from the Lower Cretaceous Xinminpu Group of the Yujingzi Basin, Jiuquan area, Gansu Province, northwestern China. It is represented by an articulated posterior portion of the skull and is unique in having an extremely long, pendant and crescentic paroccipital process with its ventral tip projecting far beyond the ventral level of the occipital condyle. Phylogenetic analysis recovers Jintasaurus as the sister-taxon to Hadrosauroidea, more derived than other Early Cretaceous hadrosauriforms and Protohadros from the early Late Cretaceous of North America. This discovery adds one more close relative to Hadrosauroidea in Asia and supports an Asian origin for this group.
Coronitic metagabbro and eclogite from the Grenville Province of western Quebec: interpretation of U–Pb geochronology and metamorphism
Authors: Indares Aphrodite , Dunning Greg
Published: December 2009

We present new U–Pb and metamorphic data on high-pressure coronitic metagabbros from three distinct structural settings in the Parautochthonous Belt of the Grenville Province in western Quebec. Intrusive ages are (i) [Formula: see text], for metagabbro close to the Grenville Front, correlative with the Sudbury dykes, defined in Ontario; (ii) [Formula: see text] for an eclogitized lens at the base of the highest structural level (SL4), a new age for mafic magmatism in the western Grenville; and (iii) [Formula: see text] for metagabbro from SL4, interpreted as correlative with metagabbros from the Algonquin and Shawanaga domains in Ontario. Metamorphism in all cases is Grenvillian, with the best constrained age of 1069 ± 3 Ma for the metagabbro of SL4. Metamorphic grade increases from the Grenville Front to the south. The mafic rocks preserve relict igneous textures overprinted by garnet + clinopyroxene that developed as coronas and (or) pseudomorphs after igneous phases. The highest grade metagabbros contain omphacite and some lack primary plagioclase, therefore being eclogites. However, interpretation of textures and mineral chemistry indicates that they were equilibrated during decompression (at 1350 MPa and 720 °C, sample 51; and at 1200 MPa and 740 °C, sample 29), so maximum depths of burial remain unconstrained. Their evolution is interpreted as follows: (i) high-pressure metamorphism by burial of the Laurentian margin under accreted terranes thrust toward the northwest between 1080 and 1060 Ma; (ii) residence at intermediate crustal levels, for a few tens of millions of years; and (iii) rapid exhumation by renewed thrusting that led to the emplacement of the high-pressure units over the northerly adjacent structural units of the Parautochthonous Belt.
The chronology of speleothem deposition in northern Yukon and its relationships to permafrost
Authors: Lauriol B. , Ford D. C. , Cinq-Mars J. , Morris W. A.
Published: December 2009

In the northern Yukon there is a significant group of limestone caves in an area that was not glaciated during the Quaternary. Permafrost appears to have played an important role in restricting calcite speleothem deposition in the caves. U/Th dating and stable isotopic studies indicate that the deposits form two distinct groups, a first group younger than 350 ka, and a second group older than the 350 ka BP limit of the conventional U/Th alpha spectrometric dating method. Two large samples from the second group yield sequences of magnetic declinations and inclinations with reversed and normal polarity, perhaps from the Tertiary. The pollen content of five speleothems, the modes of calcite deposition, and stable isotopic analyses indicate that the speleothems were deposited under a cold regime. It is suggested that the ancient speleothems were deposited at a time when permafrost was absent, during the later Tertiary or at the beginning of the Quaternary period. The establishment and maintenance of permafrost throughout the Quaternary has prevented the formation of younger speleothems, except at a few cave entrances where the active layer may have deepened during interglacials.
Cryostratigraphy, paleogeography, and climate change during the early Holocene warm interval, western Arctic coast, Canada
Authors: Burn C. R.
Published: December 2009

Botanical and cryostratigraphic records from northwest Canada indicate that the climate of the early Holocene was considerably warmer than today: tree line was over 100 km farther north; and a thaw unconformity, dating from 8000 14C years BP, formed at the base of an active layer 2.5 times thicker than at present. Numerous thermokarst-lake basins formed in the preceding millennia. Both the botanical and cryostratigraphic indices described are products of summer conditions. Previous reconstructions of early Holocene climate have not assessed the significance of paleocoastal location on the seasonality and extent of apparent climate warming. At present, there is a steep gradient in growing-season conditions between cooler sites on the Beaufort Sea coast and warmer, inland locations. Winter conditions are more uniform because both sea and land are snow-covered. Coastal retreat in the region has been rapid, due to sea level rising over a gently sloping shelf containing readily erodible sediments. The coastline has moved about 100 km southward during the Holocene. The increasing proximity to the coast, through time, of points currently within 100 km of the sea may account for between one and two thirds of the cooling in summer climate experienced there since the mid-Holocene.
Numerical simulation of permafrost evolution as a part of sedimentary basin modeling: permafrost in the Pliocene–Holocene climate history of the Urengoy field in the West Siberian basin
Authors: Galushkin Yurii
Published: December 2009

Present-day temperature profile may be used as an important constraint for reconstruction of the thermal regime in sedimentary basin modeling. This type of profile is significantly non-steady state, especially for basins located at high and middle latitudes. However, estimations of past thermal regimes are indefinite and often limited by knowledge of past glaciations and by the simple two-layer model usually employed. In this paper, permafrost modeling was carried out as a continuation of basin modeling of the sedimentary section of Urengoy field of the West Siberian basin (66°N, 77°E). Consideration of surface temperatures beginning with the Triassic, a refined initial temperature distribution, permafrost modeling for the past 3.4 Ma, and use of a real lithological cross section distinguish this approach from previous studies. Depth and time variations in thermophysical parameters of rocks (heat conductivity, heat capacity, unfrozen water content, salt content, and porosity) had a considerable influence on the results of modeling. The time 3.4 Ma, when air temperatures in the area became lower than 0 °C, has been considered as the initial time for permafrost modeling. According to the model, initial temperatures deviated 10–15 °C from their present-day values due to climate variations during the last 3.4 Ma. Deviations in the value of heat flow can exceed 100%. There were about five glacial periods in the Late Pliocene and nearly the same number in the Pleistocene in the area. The estimated thickness of permafrost did not exceed 650 m and the depth of the lower boundary of methane hydrate stability did not exceed 900 m (from the ground surface). Today, the predicted depths of permafrost [Formula: see text] and of hydrate stability (from 250 to 700 m) are in reasonable agreement with the observed values for the Urengoy area.
Early Jurassic evolution of the northern Stikinian arc: evidence from the Laberge Group, northwestern British Columbia
Authors: Johannson Gary G. , Smith Paul L. , Gordey Steven P.
Published: December 2009

This study resolves fundamental questions concerning the age, provenance, and depositional history of Laberge Group strata in the Whitehorse Trough. The Jurassic Inklin Formation straddles the Stikine and Cache Creek terranes along much of the length of the Whitehorse Trough. Ammonite biochronology indicates an age range of early Sinemurian to late Pliensbachian and provides the temporal framework for interpreting basin history. Strong temporal trends in both paleocurrent patterns and sandstone–conglomerate petrofacies allow definition of three discrete phases in basin-fill history. Stable tectonics characterized by relative volcanic quiescence and low sedimentation rates prevailed during the Sinemurian. Sinemurian sandstone–conglomerate petrofacies record a transitional-arc provenance derived from erosion of the Upper Triassic volcanic pile, flanking coastal sediments, and arc roots of Stikinia to the southwest. During the early Pliensbachian, arc dissection was interrupted by a major magmatic episode with widespread rejuvenated volcanism that caused a strong provenance shift to volcanigenic sources, indicating derivation from a largely undissected Stikinian arc. Southwest-derived, northerly longitudinal paleoflow during the Sinemurian changed to opposed bidirectional radial or transverse paleoflow systems in the early Pliensbachian. Cannibalism of broadly coeval basinal strata and (or) reflected sediment gravity flows were the result of episodic growth of a mobile outer forearc rise, initiating southwest-directed paleoflow systems during the early Pliensbachian and the possible development of a ridged forearc phase. U–Pb dates of [Formula: see text] and 186 ± 1 Ma from a granite clast and tuff unit, respectively, of the Kunae Zone (early late Pliensbachian) and sandstone–conglomerate petrofacies indicate a late Pliensbachian depositional regime dominated by tectonic controls. The influx of granitic detritus indicates a rapid transition to a fully dissected arc provenance, where accelerated uplift of segments of the arc massif, accompanied by intra-arc strike-slip faulting, resulted in rapid arc dissection and unroofing of comagmatic Pliensbachian plutons.
Late Holocene sedimentation in Saanich Inlet, British Columbia, and its paleoseismic implications
Authors: Blais-Stevens A. , Clague J. J. , Bobrowsky P. T. , Patterson R. T.
Published: December 2009

Eight piston cores of sediment spanning the last 1500 years were collected from Saanich Inlet, an anoxic fiord on southern Vancouver Island, to obtain information on sedimentation and prehistoric earthquake activity. The cores consist mainly of fine-grained varved sediments, but include massive layers deposited by subaqueous debris flows. The debris flows may have been triggered by earthquakes or by the buildup of fine sediment on the walls of the inlet. Cesium-137 and 210Pb data, 14C ages, and varve counts were used to date and correlate massive layers in the eight cores. The uppermost massive layer in two cores may record a magnitude 7.2 earthquake that occurred in 1946 near Comox, British Columbia, 200 km north-northwest of Saanich Inlet. Seven older layers are found in two or more cores and are about 200, 440, 550, 800–850, 1050–1100, 1100–1150, and 1450–1500 years old. Two of these older layers may correlate with previously documented earthquakes in the region. There is an average of one massive layer per 116 varves in the core with the greatest number of such layers, which is broadly consistent with the expected periodicity of moderate to large earthquakes in the region, on average, one earthquake producing local Modified Mercalli Intensity VII or VIII per century. Saanich Inlet may contain a proxy record of all moderate and large earthquakes that have affected southwestern British Columbia during Holocene time, but some of the massive layers do not appear to correlate from core to core and undoubtedly are nonseismically generated deposits.
Early Tertiary thermotectonic history of the northern Yukon and adjacent Northwest Territories, Arctic Canada
Authors: O'Sullivan Paul B. , Lane Larry S.
Published: December 2009

Apatite fission-track data from 16 sedimentary and crystalline rock samples indicate rapid regional Early Eocene denudation within the onshore Beaufort–Mackenzie region of northwestern Canada. Rocks exposed in the area of the Big Fish River, Northwest Territories, cooled rapidly from paleotemperatures of >80–110 °C to <6 0°C at ca. 56 ± 2 Ma, probably in response to kilometre-scale denudation associated with regional structuring. The data suggest the region experienced a geothermal gradient of ~28 °C/km prior to rapid cooling, with ~2.7 km of section having been removed from the top of the exposed section in the Moose Channel Formation and ~3.8 km from the top of the exposed Cuesta Creek Member. Farther to the west, rocks exposed in the headwaters of the Blow River in the Barn Mountains, Yukon Territories, were exposed to paleotemperatures above 110 °C in the Late Paleocene prior to rapid cooling from these elevated paleotemperatures due to kilometre-scale denudation at ca. 56 ± 2 Ma. Exposure of these samples at the surface today requires that a minimum of ~3.8 km of denudation occurred since they began cooling below ~110 °C. The apatite analyses indicate that rocks exposed in the northern Yukon and Northwest Territories experienced rapid cooling during the Early Eocene in response to kilometre-scale denudation, associated with early Tertiary folding and thrusting in the northern Cordillera. Early Eocene cooling–uplift ages for onshore sections are slightly older than the Middle Eocene ages previously documented for the adjacent offshore foldbelt and suggest that the deformation progressed toward the foreland of the foldbelt through time.
Petrogenetic significance of chromian spinels from the Sudbury Ignecus Complex, Ontario, Canada
Authors: Zhou Mei-Fu , Keays Reid R. , Lightfoot Peter C. , Morrison Gordon G. , Moore Michelle L.
Published: December 2009

Chromian spinels occur in mafic–ultramafic inclusions in the Sublayer of the Sudbury Igneous Complex (SIC) as well as in mafic–ultramafic rocks in the immediate footwall of the Sublayer. The host rocks are pyroxenite and melanorite with minor dunite, harzburgite, and melatroctolite. As common accessory phases in these rocks, the chromian spinels display euhedral or subhedral forms and are included in olivine and orthopyroxene. Chromian spinel grains generally have ilmenite lamellae and contain abundant inclusions (zircon, olivine, diopside, plagioclase, biotite, and sulfide). All the chromian spinels have similar trace element abundances and are rich in TiO2 (0.5–15 wt.%). They have constant Cr# (100Cr/(Cr + Al)) (55–70) and exhibit a continuum in composition that traverses the normal fields of spinels in a Al–(Fe3+ + 2Ti)–Cr triangular diagram. This continuum extends to that of the composition of chromian magnetite in the host norite matrix to the mafic–ultramafic inclusions. This continuum in composition of the spinels suggests that the noritic matrix to the Sublayer formed from the same magma as the inclusions. A positive correlation between the Cr and Al contents of the spinels was probably produced by dilution of these elements by Fe3+ contributed, perhaps, by a plagioclase-saturated melt. Zircon inclusions in a chromian spinel grain reflect incorporation of crustal, felsic materials into the magma before crystallization of chromian spinel. The chemical characteristics and mineral inclusions of the spinels suggest that the Sublayer formed in response to magma mixing. It is suggested that subsequent to the formation of the crustal melt, mantle-derived high-Mg magmas mixed vigourously with this and generated the magmatic sulfides that eventually formed the Ni – Cu – platinum-group elements sulfide ore deposits. Some of the early crystallization products of the high-Mg magma settled to the chamber floor, where they partially mixed with the crustal melt and formed the mafic–ultramafic inclusions and footwall complexes.
On the Submarine Geomorphology Along the East Coast of Baffin Island
Authors: Løken O. H. , Hodgson D. A.
Published: December 2009

A reconnaissance survey was made of the submarine geomorphology along the east coast of Baffin Island using an echo sounder. The survey focused on: (1) the continental slope, (2) the continental shelf, and (3) the fiords. The depth contours on the continental slope are roughly parallel to the coastline. The overall steepness of the slope is typically 2–3°, with the steeper sections near the top. Small irregularities of unknown origin are commonly found in the slope profiles.Transverse troughs with depths of almost 900 m are the most distinct features of the 30–50 km-wide continental shelf. The larger channels are associated with major fiord–valley systems on the island. Ridges, interpreted as lateral moraines, extend along the trough margins. Marginal channels commonly found along glaciated coasts appear to be absent from this section of the Baffin Island coast, but subbottom profiles are not yet available.The fiords of east Baffin Island show the typical fiord characteristics and reach a maximum depth of 900 m. The deepest part is usually below the highest mountains along the fiord. All fiords continue into offshore channels of varying depth.Many significant changes to the bathymetric map of the west side of Baffin Bay have been made. This is partly due to the survey plan and partly to the greatly improved plotting charts which were used.
Paleogeography of Northwestern New Brunswick during the Llandovery: a Study of the Provenance of the Siegas Formation
Authors: Hamilton-Smith Terence
Published: December 2009

The Siegas Formation of northwestern New Brunswick and northeastern Maine is composed mainly of sandstone and slate and has yielded fossils of early Llandovery age. It conformably overlies older rocks, indicating that there was continuous sedimentation in the Siegas area during the time of the Taconic orogeny. The formation consists of the three laterally equivalent facies, the lithic wacke, the quartz arenite, and the arkosic facies. Sandstones of the lithic wacke facies are made up mainly of mafic volcanic grains and their decomposition products: sodic plagioclase, angular quartz, and pyroxene. Sandstones of the quartz arenite facies consist mainly of medium-grained rounded quartz. Sandstones of the arkosic facies are composed mainly of potassium feldspar, quartz, and felsic plutonic fragments. The source rocks of the Siegas Formation included mafic volcanic rocks (probably andesite), felsic plutonic rocks (possibly granitic), and quartzose sandstones.Facies, paleocurrents, and regional paleogeographic evidence indicate that the source area of the Siegas Formation was in northwestern New Brunswick, a region now covered by Devonian sedimentary rocks. The source area was probably an isolated, relatively discrete uplift similar to others previously described in northeastern Maine. It probably consisted of Cambrian or Ordovician quartzose sandstones like those of the Quebec Group of the Temiscouata area, overlain by middle Ordovician andesites like those of northeastern Maine, and intruded by a "granitic" body like the Rockabema Quartz Diorite of the Weeksboro – Lunksoos Lake anticlinorium in eastern Maine. The site of active erosion of this uplift probably was shifted to the northwest in the late Llandovery, possibly accompanied by the development of local mafic volcanism.
The Stratigraphy and Morphology of Para-glacial Alluvial Fans in South-central British Columbia
Authors: Ryder J. M.
Published: December 2009

Alluvial fan construction within the interior valleys of southern British Columbia was dependent upon temporary conditions resulting from deglaciation. Glacial drift was reworked by streams and mudflows to form fans whose composition is dependent upon the nature of the drift supply and the hydrologic character of the parent basin.Stratigraphic evidence suggests that fan building commenced soon after valley floors became ice-free, continued during post-glacial aggradation by major rivers and for some time after wards. Most recently, fans were built upon degradational river terraces. Mazama volcanic ash within fans indicates that their construction continued until after 6600 years B.P. After deposition ceased many fans were dissected either as local base-levels were lowered under the control of degrading major rivers or by fan-head trenching initiated as the debris supply declined. Where fan building persisted during degradation, multi-level fans were constructed.