bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of Knee Injury History on Health-Related Quality of Life in Adolescent Athletes
Authors: Lam Kenneth C. , Markbreiter Jessica G.
Published: October 2017

Context: Current evidence suggests that, despite returning to full participation, physically active adults with a previous knee injury experience lower health-related quality of life (HRQOL) than those with no knee injury history. It is unknown if this relationship is present in adolescent athletes. Objective: To determine the impact of knee injury history on HRQOL in adolescent athletes who were medically cleared for full participation. Design: Cross-sectional. Setting: Athletic training clinics. Participants: A convenience sample of 183 adolescent athletes, who were medically cleared for full participation, were grouped by self-report of a previous knee injury: positive knee injury history (HIS; n = 36, age = 15.7 [1.4] y, height = 168.0 [11.9] cm, and weight = 71.8 [11.9] kg) and no knee injury history (NO-HIS; n = 147, age = 15.5 [1.4] y, height = 166.0 [10.5] cm, and weight = 67.6 [14.6] kg). Interventions: Participants completed the Pediatric International Knee Documentation Committee form and Pediatric Quality of Life Inventory during their preparticipation examination. Main Outcome Measures: Generalized linear models were used to compare group differences for the total and subscale scores of the Pediatric International Knee Documentation Committee and Pediatric Quality of Life Inventory. Results: Main effects of injury group indicated that the HIS group reported significantly lower scores than the NO-HIS group for the Pediatric International Knee Documentation Committee total score (P < .001; HIS = 79.2 [21.7], NO-HIS = 95.8 [8.6]) and for the Pediatric Quality of Life Inventory total (P = .001; HIS = 85.7 [10.9], NO-HIS = 90.9 [7.3]), physical functioning (P = .002; HIS = 86.7 [13.6], NO-HIS = 92.1 [8.2]), school functioning (P = .01; HIS = 80.6 [12.4], NO-HIS = 86.8 [12.2]), and social functioning (P = .01; HIS = 89.3 [12.4], NO-HIS = 94.6 [8.9]) scores. No group differences were reported for the emotional functioning subscale (P = .13; HIS = 85.7 [17.7], NO-HIS = 89.7 [13.1]). No interactions or main effects of sex were reported (P > .05). Conclusions: Our findings suggest that, despite returning to full sport participation, adolescent athletes with a previous knee injury generally experience lower HRQOL than their peers with no knee injury history, specifically for knee-specific HRQOL, physical functioning, school functioning, and social functioning. Our results are similar to previous findings reported in college athletes and military cadets.
Dancing With Derrida: Deconstructing Sportswomen’s Performances on Dancing with the Stars and Mira Quien Baila
Authors: Martin Montserrat , Spencer Nancy , Bruce Toni
Published: October 2017

Feminists have long wrestled with the binary of gender difference in sport, employing diverse theoretical and empirical approaches to understand how difference is constructed, maintained and challenged. In this article, we engage with Jacques Derrida’s work on deconstruction anddifférance. Specifically, we engage with deconstruction’s double gesture in order to firstly identify, and later resist and disorganize the hierarchical oppositions of gender difference—masculine versus feminine. In particular, we are interested in the play of gender difference anddifféranceas they emerge in a context that juxtaposes sportswomen’s engagement in divergent sites of physical activity—dancing and sport. We aim to demonstrate how deconstructing sportswomen’s performances on televised dance competitions contributes useful ideas to think about the feminine beyond an oppositional gender binary frame. To illustrate our theoretical discussion, we analyze female athletes’ performances on popular, transnational, televised, celebrity dancing competitions in Spain, the U.S. and New Zealand.
Radical Sports Journalism?: Reflections on ‘Alternative’ Approaches to Covering Sport-Related Social Issues
Authors: Forde Shawn , Wilson Brian
Published: October 2017

In this paper we report findings from a study of what we are calling ‘sports media activism’ (or ‘SMA’). We were interested in how, why, and for what purposes a range of sport media activists are engaging with sport-related social issues through different media. This research contributes to a limited body of literature on sport-related activism, and especially to thinking about the role of media in sport-related activism. By ‘taking sport seriously’ in this paper, we consider what might be learned by focusing on the experiences of those creating and contributing to sport-related activism and alternative media. Also, by assessing a range of projects that we include under the sport media activism umbrella—each with their own goals and intentions for change—we think there is room to inform thinking about ‘alternative’ media more broadly.
“It’s This Thing of Being an Olympian That You Don’t Get From Anything Else”: Changing Experiences of Canadian Individual-Sport Athletes With Olympic Team Selection
Authors: McEwen Carolyn E. , Hurd Clarke Laura , Bennett Erica V. , Dawson Kimberley A. , Crocker Peter R.E.
Published: October 2017

The purpose of this study was to examine elite Canadian individual-sport athletes’ experiences with an Olympic team-selection process. Six nonselected Canadian individual-sport athletes who were attempting to qualify for the Olympics took part in 3 semistructured interviews during the Olympic team-selection process, after they gained knowledge of their selection status, and after the Olympic Games. Data were analyzed using interpretative phenomenological analysis. Three major themes emerged from the interpretation of the athletes’ experiences: (a) pursuing and expressing the Olympic athlete identity; (b) navigating the Olympic team-selection process: expectations, barriers, and tensions; and (c) moving on: reactions, life-goal reinvestment, and athletic-goal adjustment. Participants’ experiences were shaped by personal motivation and social expectations, with changes shifting across the 3 interview periods. Athletes attempted to manage the discontent of nonselection through processes of positive reappraisal, athletic-goal adjustment, and accentuating other life goals and identities.
Swope Supernova Survey 2017a (SSS17a), the optical counterpart to a gravitational wave source
Authors: Coulter D. A. , Foley R. J. , Kilpatrick C. D. , Drout M. R. , Piro A. L. , Shappee B. J. , Siebert M. R. , Simon J. D. , Ulloa N. , Kasen D. , Madore B. F. , Murguia-Berthier A. , Pan Y.-C. , Prochaska J. X. , Ramirez-Ruiz E. , Rest A. , Rojas-Bravo C.
Published: October 2017

Photons from a gravitational wave event

Two neutron stars merging together generate a gravitational wave signal and have also been predicted to emit electromagnetic radiation. When the gravitational wave event GW170817 was detected, astronomers rushed to search for the source using conventional telescopes (see the Introduction by Smith). Coulter
et al.
describe how the One-Meter Two-Hemispheres (1M2H) collaboration was the first to locate the electromagnetic source. Drout
et al.
present the 1M2H measurements of its optical and infrared brightness, and Shappee
et al.
report their spectroscopy of the event, which is unlike previously detected astronomical transient sources. Kilpatrick
et al.
show how these observations can be explained by an explosion known as a kilonova, which produces large quantities of heavy elements in nuclear reactions.

Science
, this issue p.
1556
, p.
1570
, p.
1574
, p.
1583
; see also p.
1554
Nodular pulmonary amyloidosis: a complex disease with malignancy association
Authors: Core Jacob M , Alsaad Ali A , Jiang Liuyan , Patel Neal M
Published: October 2017

Pulmonary amyloidosis is a rare disease that incorporates deposition of amyloid microfibril material in the lung parenchyma. The condition generally presents as an indolent subacute-to-chronic pulmonary disease and requires tissue biopsy to establish the diagnosis. Nodular pulmonary amyloidosis, a subtype of pulmonary amyloidosis, is characterised by special radiographic and pathological features. While the disease can be associated with inflammatory conditions; its association with mucosal-associated lymphoid tissue (MALT lymphoma) is unusual and carries management challenges. Herein, we illustrate a case study of nodular pulmonary amyloidosis associated with underlying MALT lymphoma in a patient with known systemic lupus erythematosus. The aim of this article is to share the management experience of this complex condition with the medical community and to conduct an up-to-date literature review on nodular pulmonary amyloidosis.
Cervical and breast cancer screening participation and utilisation of maternal health services: a cross-sectional study among immigrant women in Southern Italy
Authors: Bianco Aida , Larosa Elisabetta , Pileggi Claudia , Nobile Carmelo G A , Pavia Maria
Published: October 2017

Objectives

Women make up approximately half of the world’s one billion migrants. Immigrant women tend to be one of the most vulnerable population groups with respect to healthcare. Cancer screening (CS) and maternal and reproductive health have been included among the 10 main issues pertinent to women’s health. The aim of this study is to explore breast and cervical CS participation and to acquire information regarding access to healthcare services during pregnancy, childbirth and the postpartum period among age eligible immigrant women in Southern Italy.

Methods

A structured questionnaire was used to collect data from each participant. Women aged 25–64 years who had not had a hysterectomy and women aged 50–69 years without history of breast cancer were considered eligible for the evaluation of cervical and breast CS participation, respectively. Moreover, women who had delivered at least once in Italy were enrolled to describe antenatal and postpartum care services use. All women were recruited through the third sector and non-profit organisations (NPOs).

Results

Rate of cervical CS among the 419 eligible women was low (39.1%), and about one-third had had a Pap test for screening purposes within a 3-year period from interview (32.8%). Regarding breast CS practices, of the 125 eligible women 45.6% had had a mammography for control purposes and less than a quarter (26, 20.8%) had their mammography within the recommended time interval of 2 years. About 80% of the respondents did not report difficulties of access and use of antenatal and postpartum services.

Conclusion

This study provides currently unavailable information about adherence to CS and maternal and child health that could encourage future research to develop and test culturally appropriate, women-centred strategies for promoting timely and regular CS among immigrant women in Italy.
Early sexual experiences of teenage heterosexual males in Australia: a cross-sectional survey
Authors: Chow Eric P F , Wigan Rebecca , McNulty Anna , Bell Charlotte , Johnson Mandy , Marshall Lewis , Regan David G , Owen Louise , Brotherton Julia M L , Bradshaw Catriona S , Fairley Christopher K , Russell Darren , Chen Marcus Y
Published: October 2017

Objective

There are limited data on the patterns of early sexual behaviours among Australian teenage heterosexual boys. This study describes the nature and onset of early sexual experiences in this population through a cross-sectional survey.

Design

A cross-sectional survey between 2014 and 2015

Setting

Major sexual health clinics and community sources across Australia

Participants

Heterosexual men aged 17–19 years

Results

There were 191 men in the study with a median age of 19.1 years. Median age at first oral sex was 16.4 years (IQR: 15.5–17.7) and 16.9 years (IQR: 16.0–18.0) for first vaginal sex. Most men had engaged in oral sex (89.5%) and vaginal sex (91.6%) in the previous 12 months with 32.6% reporting condom use at last vaginal sex. Of the total lifetime female partners for vaginal sex reported by men as a group (n=1187): 54.3% (n=645) were the same age as the man, 28.3% (n=336) were a year or more younger and 17.4% (n=206) were a year or more older. Prior anal sex with females was reported by 22% with 47% reporting condom use at last anal sex. Median age at first anal sex was 18.2 years (IQR: 17.3–18.8). Anal sex with a female was associated with having five or more lifetime female sexual partners for oral and vaginal sex.

Conclusions

These data provide insights into the trajectory of sexual behaviours experienced by teenage heterosexual boys following sexual debut, findings which can inform programme promoting sexual health among teenage boys.
Effects of school-based intervention by emergency medical technicians on students and their parents: a community-based prospective study of the Akashi project
Authors: Tomari Shinya , Yokota Chiaki , Nishimura Kunihiro , Hino Tenyu , Ohyama Satoshi , Arimizu Takuro , Wada Shinichi , Ohnishi Hideyuki , Toyoda Kazunori , Minematsu Kazuo
Published: October 2017

Objective

Stroke lessons for youth provided by emergency medical technicians (EMTs) may be an effective strategy to facilitate early intervention for patients with stroke. The aim of this study was to examine how effective EMT-led lessons on stroke awareness for schoolchildren were at disseminating stroke information.

Setting, participants and outcome measures

The study was performed in the city of Akashi, Hyogo, Japan (Akashi project). Children (aged 9–10 years old) at 11 public elementary schools and their parents were enrolled in this study. EMTs from the firefighting headquarters provided lessons on stroke to the children using our educational materials between September 2014 and October 2015. Each child was given our educational materials to take home and discuss stroke with their parents. The children and their parents answered questionnaires on stroke knowledge before, immediately and at 3 months after the lesson.

Results

A total of 763 children and 489 parents were enrolled (ie, 64% of children). The scores of either stroke symptoms or risk factors were significantly higher immediately and at 3 months after the lesson, compared with before the lesson, both in children and the parents (p<0.01). Compared with the baseline in both groups (58% in children, 83% in parents), the meaning of the FAST mnemonic at 3 months (88%, 94%), as well as at immediately after the lesson (90%, 89%), was significantly higher (p<0.001).

Conclusion

Stroke education by EMTs was effective in increasing stroke awareness in elementary school children, as well as their parents.
Barriers and facilitators to healthy lifestyle and acceptability of a dietary and physical activity intervention among African Caribbean prostate cancer survivors in the UK: a qualitative study
Authors: Er Vanessa , Lane J Athene , Martin Richard M , Persad Raj , Chinegwundoh Frank , Njoku Victoria , Sutton Eileen
Published: October 2017

Objectives

Diet and lifestyle may have a role in delaying prostate cancer progression, but little is known about the health behaviours of Black British prostate cancer survivors despite this group having a higher prostate cancer mortality rate than their White counterparts. We explored the barriers and facilitators to dietary and lifestyle changes and the acceptability of a diet and physical activity intervention in African Caribbean prostate cancer survivors.

Design

We conducted semistructured in-depth interviews and used thematic analysis to code and group the data.

Participants and setting

We recruited 14 African Caribbean prostate cancer survivors via letter or at oncology follow-up appointments using purposive and convenience sampling.

Results

A prostate cancer diagnosis did not trigger dietary and lifestyle changes in most men. This lack of change was underpinned by five themes: precancer diet and lifestyle, evidence, coping with prostate cancer, ageing, and autonomy. Men perceived their diet and lifestyle to be healthy and were uncertain about the therapeutic benefits of these factors on prostate cancer recurrence. They considered a lifestyle intervention as unnecessary because their prostate-specific antigen (PSA) level was kept under control by the treatments they had received. They believed dietary and lifestyle changes should be self-initiated and motivated, but were willing to make additional changes if they were perceived to be beneficial to health. Nonetheless, some men cited advice from health professionals and social support in coping with prostate cancer as facilitators to positive dietary and lifestyle changes. A prostate cancer diagnosis and ageing also heightened men’s awareness of their health, particularly in regards to their body weight.

Conclusions

A dietary and physical activity intervention framed as helping men to regain fitness and aid post-treatment recovery aimed at men with elevated PSA may be appealing and acceptable to African Caribbean prostate cancer survivors.
Protocol for a scoping review to identify and map the global health personnel considered skilled attendants at birth in low and middle-income countries between 2000 and 2015
Authors: Hobbs Amy J , Moller Ann-Beth , Carvajal-Aguirre Liliana , Amouzou Agbessi , Chou Doris , Say Lale
Published: October 2017

Introduction

Despite progress towards the Millennium Development Goals (MDG), maternal mortality remains high in countries where there are shortages of skilled personnel able to manage and provide quality care during pregnancy and childbirth. The ‘percentage of births attended by skilled health personnel’ (SAB, skilled attendants at birth) was a key indicator for tracking progress since the MDGs and is part of the Sustainable Development Goal agenda. However, due to contextual differences between and within countries on the definition of SAB, a lack of clarity exists around the training, competencies, and skills they are qualified to perform. In this paper, we outline a scoping review protocol that poses to identify and map the health personnel considered SAB in low and middle-income countries (LMIC).

Methods and analysis

A search will be conducted for the years 2000–2015 in PubMed/MEDLINE, EMBASE, CINAHL Complete, Cochrane Database of Systematic Reviews, POPLINE and the WHO Global Health Library. A manual search of reference lists from identified studies or systematic reviews and a hand search of the literature from international partner organisations will be done. Original studies conducted in LMIC that assessed health personnel (paid or voluntary) providing interventions during the intrapartum period will be considered for inclusion.

Ethics and dissemination

A scoping review is a secondary analysis of published literature and does not require ethics approval. This scoping review proposes to synthesise data on the training, competency and skills of identified SAB and expands on other efforts to describe this global health workforce. The results will inform recommendations around improved coverage measurement and reporting of SAB moving forward, allowing for more accurate, consistent and timely data able to guide decisions and action around planning and implementation of maternal and newborn health programme globally. Data will be disseminated through a peer-reviewed manuscript, conferences and to key stakeholders within international organisations.
Activation of professional and personal network relations when experiencing a symptom: a population-based cross-sectional study
Authors: Elnegaard Sandra , Andersen Rikke Sand , Pedersen Anette Fischer , Jarbøl Dorte Ejg
Published: October 2017

Objective

To describe patterns of disclosure of symptoms experienced among people in the general population to persons in their personal and/or professional network.

Design

A population-based cross-sectional study. Data were collected from a web-based survey.

Setting

The general population in Denmark.

Participants

100 000 individuals randomly selected, representative of the adult Danish population aged ≥20 years were invited. Approximately 5% were not eligible for inclusion. 49 706 (men=23 240; women=26 466) of 95 253 eligible individuals completed the questionnaire; yielding a response rate of 52.2%. Individuals completing all questions regarding social network relations form the study base (n=44 313).

Primary and secondary outcome measures

Activation of personal and/or professional relations when experiencing a symptom.

Results

The 44 313 individuals reported in total 260 079 symptom experiences within the last 4 weeks. No professional network relation was used in two-thirds of all reported symptoms. The general practitioner (GP) was the most frequently reported professional relation activated (22.5%). People reporting to have available personal relations were slightly less inclined to contact the GP (21.9%) when experiencing a symptom compared with people with no reported personal relations (26.8%). The most commonly activated personal relations were spouse/partner (56.4%) and friend (19.6%). More than a quarter of all reported symptom experiences was not shared with anyone, personal nor professional. The symptom experiences with the lowest frequency of network activation were symptoms such as black stool, constipation, change in stool texture and frequent urination.

Conclusion

This study emphasises variation in the activation of network relations when experiencing a symptom. Symptoms were shared with both personal and professional relations, but different patterns of disclosures were discovered. For symptoms derived from the urogenital or colorectal region, the use of both personal and professional relations was relatively small, which might indicate reticence to involve other people when experiencing symptoms of that nature.
Acute glutamine ingestion modulates lymphocytic responses to exhaustive exercise in the heat
Authors: Zheng Chen , Chen Xiang-Ke , Zhou Yue
Published: October 2017

The purpose of this study was to determine if acute intake of glutamine modulates homeostatic, hematologic, immune, and inflammatory responses to exhaustive exercise in the heat. Thirteen healthy, untrained young men participated in this randomized, double-blind, placebo-controlled, crossover study. They served as their own control and completed 2 trials of treadmill exercise at 40% maximal oxygen uptake to exhaustion in a hot environment (temperature, 38.0 ± 1.0 °C; relative humidity, 60.0% ± 5.0%; oxygen, 20.8%) following placebo (PLA) and glutamine (GLN) consumption. Heart rate, gastrointestinal temperature, forehead temperature, the rating of perceived exertion, and body weight were measured. Blood samples were collected before and after exercise. After exhaustive exercise in the heat (PLA vs. GLN: 42.0 ± 9.5 vs. 39.6 ± 7.8 min, p > 0.05), significant changes in homeostatic, hematologic, and immune parameters (elevated natural killer (NK) cells and neutrophils, and reduced CD4+/CD8+ ratio and CD19+ lymphocytes) were found in the control group owing to the time effect (p < 0.05). Moreover, a condition × time interaction effect was observed for the absolute count of CD3+ (F = 4.26, p < 0.05) and CD3+CD8+ T lymphocytes (F = 4.27, p < 0.05), which were elevated following acute glutamine intervention. While a potential interaction effect was also observed for the absolute count of CD3+CD4+ T lymphocytes (F = 3.21, p = 0.08), no condition or interaction effects were found for any other outcome measures. The results of this study suggest that acute glutamine ingestion evokes CD3+ and CD3+CD8+ T lymphocytosis but does not modulate neutrophil and NK cell leukocytosis and immune disturbances after exhaustive exercise in the heat.
Sediment parameters and environment discrimination: an application of multivariate statistics
Authors: Greenwood Brian
Published: October 2017

Multivariate discriminant analysis is shown to be a useful tool in delineating sedimentary environments on the basis of quantitative sediment properties. Size–frequency statistics calculated by moments provide environmental indicators for wave-lain and aeolian sands from Barnstaple Bay, England. Linear discriminant analysis proves useful in classifying sediments of unknown origin and of varied mineralogical composition.
Cratonic reactivation in the Precambrian basement of western Canada. I. Deformation and chemistry
Authors: Burwash R. A. , Krupička J.
Published: October 2017

The study of petrographic, chemical, and physical properties of 183 unweathered drill cores from oil wells which have penetrated the crystalline basement underlying the Western Canadian sedimentary basin supplements previous data from this area. For the investigated area of approximately 400 000 miles2 (1 000 000 km2), lying between the latitudes 49° and 62 °N, the available data suggest the following: (i) The existence of a broad, east northeast–west southwest striking mobile zone between Great Slave Lake and southern Alberta and central Saskatchewan (the Athabasca mobile zone) containing a high proportion of largely pre-Hudsonian crystalline rocks, which underwent strong postcrystalline deformation and metasomatic recrystallization (poly-metamorphism) during the Hudsonian orogeny, 1700–1900 m.y. ago. (ii) A close relationship between the degree of postcrystalline (syn-crystalline) deformation and the intensity of metasomatic recrystallization. (iii) The possibility of large-scale regional K-metasomatism and granitization in deformed crystalline zones leading to microclinization of acid and intermediate rocks,(iv) A high proportion of reworked older rocks and the probable non-eugeosynclinal character of the metamorphosed supracrustal rocks in the mobile zone, (v) The very strong influence of postcrystalline deformation and recrystallization upon isotopic age determinations, (vi) The wide coexistence of newly formed microcline with low-grade minerals like chlorite and epidote, challenging the validity of the use of microcline as a metamorphic facies index mineral.
On the mechanics of the intrusion of sills
Authors: Gretener P. E.
Published: October 2017

Diabase sills contain material originating from the base of the crust or the upper mantle. As a result they must be fed by dike- or plug-like bodies. The formation of a sill thus represents a major reorientation of the form of the intrusion. Tabular intrusive bodies tend to orient themselves perpendicular to the least compressive principal stress axis as shown by E. M. Anderson. It is suggested that diabase sills form under sedimentary strata in which the two horizontal principal stresses exceed the vertical stress (Sx > Sy > Sz). Such strata act as stress barriers and prevent further ascent of the magma, In order for this situation to occur the sediments must be in compression in the x-direction and confined in the y-direction. The parameter of importance to produce the above state of stress is the effective Poisson's ratio.
The Northwest Atlantic Mid-Ocean Canyon
Authors: Heezen Bruce C. , Johnson G. Leonard , Hollister Charles D.
Published: October 2017

The Northwest Atlantic Mid-Ocean Canyon is a depositional–erosional linear feature which extends southward from the northern Labrador Sea to the Sohm Abyssal Plain. Analysis of the data accumulated over the past 20 yr allows us to conclude: (1) The canyon does not have any major tributaries; (2) it is Quaternary in age; and (3) it is not a tectonic feature. However, neither the source nor the sedimentary process which constructed the canyon can as yet be established.
Etude hydrogeomorphologique dans la region du Lac Maskinongé, Québec
Authors: Grenier Claude , Denis Robert
Published: October 2017

Additional water supplies are urgently needed in the Lake Maskinongé area, some 110 km northeast of Montreal. To hasten if possible discovery of more productive water-bearing formations, a joint investigation was undertaken by a hydrogeologist and a morpho-sedimentologist, both scientists with the Départment des Richesses naturelles du Québec.The area is in the boundary zone between the Canadian Shield and the St. Lawrence Lowlands. It is also a limit zone for Quaternary deposits, for here are, interstratified one with the other, drift deposits of St. Narcisse terminal moraine of Wisconsin age (10 500 yrs B.P.), stratified drift, sediments deposited in the Champlain Sea, and fluviatile deposits.The mean values of the porosity and the permeability coefficients of these surficial formations is about 39%, and 165 × 10−4 cm/s respectively. Because of these properties, and because of their volume and widespread distribution, the glacio-fluvial and the shore deposits have the greatest potential as aquifers.
Active Thermokarst Processes, Eastern Banks Island, Western Canadian Arctic
Authors: French H. M.
Published: October 2017

Active thermokarst processes occur on the hummocky and rolling terrain of eastern Banks Island, in the western Canadian Arctic. The underlying sediments are ice-rich glacial silts, sands, and gravels. Ground ice slumps, triggered by a variety of local conditions, are particularly numerous in the area to the west of Johnson Point. Maximum rates of headwall retreat of between 6.0–8.0 m/y−1 appear typical but many slumps are short-lived and become stabilised within 30–50 summers of their initiation. Rapid thermal erosion along ice wedges gives rise to badland topography in certain areas where ice-rich silts enclose large ice wedges.
Case Study of Regional Analysis Techniques for Design Flood Estimation
Authors: Kite G. W.
Published: October 2017

Regional analysis is the term given to those techniques permitting estimation of parameters for those areas in which measurements of the parameters are not available. In this case study two techniques, index-flood regional analysis and a simplified square grid method, were used to estimate design floods for culverts on the proposed Mackenzie highway. The results of these two techniques were compared with design floods estimated by the rational equation, slope–area method and an envelope of recorded extremes. The regional analysis techniques give design flows at least an order of magnitude less than those of other techniques.
Magnetic anomalies and rock magnetizations in the southern Coast Mountains, British Columbia: possible relation to subduction
Authors: Coles R. L. , Currie R. G.
Published: October 2017

A qualitative correlation is observed between the northwesterly trending Coast Mountains Magnetic Anomaly, British Columbia, and a systematic, cross-trend variation of measured magnetizations within the more mafic rocks from the Coast Plutonic Complex between 50° and 51° N. This variation partly determines the form of the anomaly. A similar variation of magnetizations in more acidic rocks is not found. Quantitative modelling, however, indicates the presence of deeper, intense magnetizations below the high anomaly in the west. A magnetic crust as much as 40 km thick is consistent with geothermal studies in this region. The deep crust of Vancouver Island is less magnetic than that under the western Coast Plutonic Complex. The concentration of magnetic material may be a consequence of a subduction process, whereby water released by dehydration of the downgoing slab promotes partial melting, with subsequent uprising of heat and melt within a hydrous environment. The water tends to maintain a relatively high oxygen pressure, at least locally, and magnetite forms in the crystallization sequence. As subduction proceeds, this region cools and the magnetic material may then produce a high magnetic anomaly.
Stratigraphic correlation of upper Proterozoic rocks of northwestern Canada
Authors: Young Grant M.
Published: October 2017

In the northwestern part of the Canadian Shield upper Proterozoic rocks of Banks Island, Brock Inlier, Coppermine area (Rae Group), Minto Arch of Victoria Island, and some small inliers have all been considered as parts of the Amundsen Basin. Formational correlation among these areas has been hindered because different stratigraphic subdivisions have been used by geologists working in different regions and because no individual has previously studied the rocks of the basin as a whole. In general, the Proterozoic rocks of the mainland coastal region have been more finely subdivided than those of Victoria Island. Most of the upper Proterozoic rocks of the mainland regions and all of those at the southern tip of Banks Island are considered to be correlative with the Glenelg Formation of Victoria Island. The Glenelg Formation is divisible into at least four widespread mappable units, each of which has diagnostic rock types, sedimentary structures, and in some cases, stromatolites corresponding closely to those of the mainland areas.The stratigraphic succession in the Shaler Group of the Minto Arch area is remarkably similar to that of the sub-Rapitan Proterozoic sequence of the Mackenzie Mountain region about 500 km to the southwest. Approximate time equivalence is proposed. If this correlation is correct then the 'older' Proterozoic sequence in the northern Cordillera is between 1200 Ma and 700 Ma in age and is therefore Neohelikian or Hadrynian in age (or both). Other corollaries of the proposed correlation are that the Rapitan and younger Proterozoic rocks of the Cordilleran region are not represented in the northwestern part of the Canadian Shield and that the older Proterozoic rocks of the Mackenzie Mountains region are probably younger than at least part of the Belt–Purcell sequence of the Canada–U.S.A. border region.New paleocurrent measurements from sandstones in the western part of the Brock Inlier indicate that dominant sediment transport was to the north-northwest. Limited data from the older Proterozoic sequence in the northern part of the Canadian Cordillera suggest transport to the west. These data are consistent with the existence of a weak positive area to the south and east of the two depocentres with possible continuity of a shallow marine shelf sea around its northern margin.
Upper Paleozoic rocks of the western Canadian Cordillera and their bearing on Cordilleran evolution
Authors: Monger J. W. H.
Published: October 2017

Volcanic and sedimentary successions of late Paleozoic and locally Mesozoic age in the Canadian Cordillera form six assemblages, based mainly on lithological association and similar stratigraphy. From east to west these assemblages are: (1) Eastern assemblage, located along the Omineca Crystalline Belt and consisting of Mississippian to Permian largely sedimentary rocks overlain by mainly Permian basic volcanics and ultramafics; (2) poorly known rocks in south-central British Columbia characterized by abundant volcaniclastics of Pennsylvanian and Permian ages; (3) Cache Creek – Bridge River assemblage of the Intermontane Bell, ranging from Lower Mississippian to Middle Jurassic and composed of chert, argillite, carbonate, basic volcanics, and ultramafics: (4) Stikine assemblage of northwestern and north-central British Columbia of Mississippian and Permian age, with basic to acidic volcanics, argillite, and carbonate; (5) Chilliwack Group on the west side of the Cascade Mountains, of Pennsylvanian and Permian age, with basic to acidic volcanics overlying a carbonate and clastic succession: and (6) Sicker–Skolai assemblage of Vancouver Island and the Saint Elias Mountains with basic to acidic volcanics overlain by sedimentary rocks. Coeval faunas in several of these assemblages differ. The assemblages may be largely unrelated to one another and came together in the Mesozoic, Their present distribution, with rocks typical of ocean basins (assemblages 1, 3) east of rocks that probably represent island arcs (assemblages, 2, 4, 5, 6) presents major problems. Two hypotheses attempt to explain this distribution. (1) The oceanic assemblages represent Paleozoic and early Mesozoic Pacific Ocean floor obducted over a broad arc terrane in the Jurassic, or (2) they are Paleozoic and early Mesozoic Pacific Ocean floor, trapped east of allochthonous arc terranes (assemblages 4, 5, 6) emplaced in the Mesozoic.
Grain size of plagioclase of the basaltic andesite dikes, Iritono, central Abukuma plateau
Authors: Ikeda Yukio
Published: October 2017

The width (W) of plagioclase crystallizing from magmas is given by the equation log [Formula: see text] where t is the crystallization time calculated from Jaeger's model and η is the viscosity of a magma. The values log 2η−1/3 for basaltic and granitic magmas under hydrous and anhydrous conditions are −0.1 and −1.0 for basaltic magmas, and −1.5 and −3.5 for granitic magmas, respectively. The equation can be explained by coarsening, thermal diffusion, and (or) material diffusion processes.
The Sudbury dikes of the Grenville Front region: paleomagnetism, petrochemistry, and K–Ar age studies
Authors: Palmer H. C. , Merz B. A. , Hayatsu A.
Published: October 2017

Northwest trending diabase dikes having alkali olivine basalt chemistry occur abundantly in the Southern Structural Province of the Canadian Shield of Ontario. In several subregions these dikes can be traced across the Grenville Front for a short distance into the Grenville Province. Within the Southern Province the dikes possess a westerly directed primary magnetization yielding a paleomagnelie pole of high precision and accuracy (168° W. 21/2°S, A95 = 21/2°). The geological age of these dikes is probably about 1250 Ma. At distances ranging from 2–8 km (northwest) of the Grenville Front these dikes are re magnetized and are characterized by anomalously high apparent K–Ar ages. The acquisition of this later magnetization having a direction of 111°, +261/2° with a corresponding pole at 161/2° W, 4° S. A95 = 61/2° takes place without any general mineralogical expression of metamorphism within the dikes. A few dikes sharing the above direction of magnetization were intruded during this time of reheating at about 1000 Ma. A short dike was located in the Grenville Front region southwest of Sudbury which possesses tholeiitic chemistry, early Paleozoic apparent K–Ar ages, and a cleaned remanence direction of 125°, +59° with a corresponding pole at 42° W, 10° N. These early Paleozoic dikes may be more extensive within the Grenville Province.
Nearshore currents and beach topography, Martinique Beach, Nova Scotia
Authors: Keeley J. R.
Published: October 2017

A series of profiles across Martinique Beach, Nova Scotia, surveyed at monthly intervals between April and October, 1974, showed the formation and subsequent disappearance of large cuspate projections on the beach face. A theoretical model of the distribution of longshore currents on the beach was used to predict the expected positions of convergences and divergences in the longshore sediment transport. The observed projections were found to occur in positions of convergence of waves generated by the southeasterly winds, dominant in the late spring. The disappearance of the cusps was associaled with the seasonal veering of wind direction to the southwest as summer advanced.The size of the seasonal changes in beach profile suggests that the morphology of Martinique Beach is controlled primarily by storm waves.
Ages of some intrusive rocks of southwestern Maine, U.S.A.
Authors: Gaudette Henri E. , Kovach Adam , Hussey II Arthur M.
Published: October 2017

Whole-rock Rb–Sr and U–Pb zircon age measurements on intrusive rocks in southwestern Maine indicate igneous activity at 400, 340, and 320 Ma. These plutonic rocks were emplaced into deformed Ordovician to Devonian(?) (and perhaps Hadrynian) rocks of the Shapleigh and Merrimack Groups. Folding of the Shapleigh and Merrimack Group rocks is interpreted to have occurred during the Acadian event, or before. The [Formula: see text] age of the Webhannet pluton in southwestern Maine sets a minimum time for Acadian deformation in this region.The 320 Ma age of the Lyman two-mica granite pluton of this study coupled with the reported ages of the Milford two-mica granite (275 Ma) and Lake Sunapee two-mica granite (323 Ma) of New Hampshire suggests a spectrum of Hercynian igneous activity in northern New England similar to that of the well established Hercynian intrusive events in the southern Appalachians and western Europe.
Isotope geochemistry of dissolved, precipitated, airborne, and fallout sulfur species associated with springs near Paige Mountain, Norman Range, N.W.T.
Authors: Everdingen Robert O. van , Shakur M. Asif , Krouse H. Roy
Published: October 2017

δ34S values determined for dissolved sulfate in water discharged by sulfurous springs near Paige Mountain identify gypsum beds in the Lower Devonian Bear Rock Formation as the sulfate source, whereas relatively low δ18O values show that as much as 30% of the sulfate may have gone through a reduction–re-oxidation cycle. Reduced sulfur species in the spring water have negative δ34S values as a result of microbiological isotope fractionation during sulfate reduction; airborne sulfur species (H2S, SO2, H2SO4) and gypsum formed through reaction of H2SO4 fallout with exposed carbonate rocks show similar negative δ34S values. Negative δ18O values for the sulfate radical in H2SO4 fallout and in the alteration product indicate that more than half of the oxygen reacting with airborne H2S is derived from water vapour.
Resistance of zircons to U–Pb resetting in a prograde metamorphic sequence of Caledonian age in East Greenland
Authors: Peucat J. J. , Tisserant D. , Caby R. , Clauer N.
Published: October 2017

In the Alpefjord area, Caledonian metamorphism from the chlorite zone to the sillimanite zone is seen to cut across the sedimentary pile of the lower Eleonore Bay Group. Zircons have been collected from quartzite layers enriched in heavy minerals.U–Pb zircon dating in the chlorite and the sillimanite zones does not reveal the Caledonian event but, instead, previous episodes at 1100 and 2500 Ma ago. The Caledonian event can be recognized in anatectic gneisses where detrital zircons are surrounded by overgrowths, K–Ar and Rb–Sr methods yield 1030–410 Ma ages on micas, with a positive correlation between the degree of apparent reselling of mica ages and the grade of the Caledonian metamorphism.The following geological interpretation of the age data is proposed. (1) A major metamorphic event occurred around 1100 Ma ago in the source area for the lower Eleonore Bay Group sediments. During this Grenvillian event, Archaean detrital zircons were affected by an episodic lead loss and a muscovite phase recorded the cooling and uplift of a basement source area. (2) Erosion of this source area occurred after 1100 Ma, followed by sedimentation of the lower Eleonore Bay Group [Formula: see text]. The 2500–1100 Ma U–Pb system remained nearly a closed system during Caledonian metamorphism up to and including sillimanite-zone conditions.This example shows the great resistance or inherited zircons to an important secondary Pb loss during Caledonian metamorphism and consequently shows that the lower-intercept ages of zircons from metasedimentary rocks do not always record the last metamorphic event observed in situ, but retain memories of previous geological events in the sedimentary source areas. By contrast, zircons separated from quartzitic xenoliths in migmatitic gneisses have recorded a disturbance in their U–Pb systems that corresponds to Caledonian partial melting.
Simulating infiltration into frozen Prairie soils in streamflow models
Authors: Gray D. M. , Landine P. G. , Granger R. J.
Published: October 2017

A major limitation of existing operational systems when applied to forecasting or synthesizing streamflow from snowmelt on watersheds in many pans of central and northern Canada is that they are incapable of accurately simulating the process of infiltration into frozen soils. The results and discussion in the paper provide a method of overcoming the problem in areas of climatic and physiographic conditions similar to those of the Prairies.Details outlining the development of a model describing snowmelt infiltration into frozen soils are presented. The model is based on the concept that for practical purposes the infiltration potential of frozen soils may be generally categorized as (1) restricted: impervious; (2) unlimited: capable of infiltrating the snow-cover water equivalent; and (3) limited: infiltration is governed by the snow-cover water equivalent and the ice content of the soil at the time of melt. An empirical relationship for calculating infiltration into frozen soils of "limited" potential is given. The improvement in performance of the United States National Weather Service river forecasting system—Sacramento model (NWSRFS) in synthesizing streamflow from snowmelt on a small watershed in western Saskatchewan gained through the use of the infiltration model is demonstrated. Different procedures of interfacing an infiltration model with an operational system, the NWSRFS, are presented, discussed, and evaluated.
Possible plinian eruptions of Paleocene age in central Yukon: evidence from volcanic ash, Norman Wells area, N.W.T.
Authors: Ricketts B. D.
Published: October 2017

Composite tuff units up to 17 m thick are exposed in strata of the Summit Creek Formation, south of Fort Norman, Northwest Territories. The age of the tuffs is bracketed between late Maastrichtian and Early Paleocene based on palynology. The geometry of the tuff beds, their consistently fine grain size (maximum particle size is 0.25 mm), their composition (less than 5% dense juvenile ash particles), and burial of plants in growth position suggest deposition by fallout from a high-altitude column of ash. Between 100 and 300 eruption–deposition events are preserved in the sequence.The nearest known volcanic source vents are located in central Yukon, about 600 km from the present exposures. Estimates of dispersal area and of volume of single ash layers and the degree of particle fragmentation compare favourably with similar parameters that have been determined from geologically recent plinian and ultraplinian eruptions.
Magnétochronologie des formations rocheuses du Mont Mégantic et des environs, Québec méridional
Authors: K.-Seguin Maurice , St-Hilaire B.
Published: October 2017

A paleomagnetic study was made to elucidate the ambiguities of the radiometric ages of Mont Megantic intrusions in relation to field observations and to determine the magnetochronology of the intruded rocks. Some 179 samples (550 specimens) were collected over 58 sites, and their magnetization was cleaned by thermal and (or) alternating field treatment. The paleopoles obtained for the Compton Formation metasediments indicate an Early to Middle Devonian age and for the overlying Frontenac Formation metavolcanics indicate an age definitely different from that for the intrusive rocks. The baked contact test on the hornfels forming the contact metamorphic aureole is positive, and the magnetization component was acquired in the Early to Late Cretaceous interval. Syenite contains two components: one with normal polarity, the other with reversed polarity; their ages are Juro-Cretaceous. The gabbro contains only one magnetization component (reversed), which was acquired in the Early Cretaceous, whereas the granite bears one component with a mostly normal polarity; its intrusive age is Late Cretaceous.The paleomagnetic ages for the intrusive rocks support the multiple intrusion interpretation; it appears that the emplacement of the intrusive bodies is Juro-Late Cretaceous. [Journal Translation]