The Fraser River delta in Greater Vancouver, Canada consists of deep soft deposits of silts and clays, and it is well known that the deep soil deposits can amplify the low frequency contents of ground motions. This st...The Fraser River delta in Greater Vancouver, Canada consists of deep soft deposits of silts and clays, and it is well known that the deep soil deposits can amplify the low frequency contents of ground motions. This study aims to investigate the eff ects of deep soil deposits in the delta on ground motion amplifi cations by using thorough site response simulations that account for the full soil profi les and a suite of recorded ground motions that covers a wide range of intensity levels. Based on both equivalent-linear and nonlinear site response simulations, the eff ects of soil depth (represented by natural period of the soil, TS) on ground motion amplifi cations for various spectral periods are clearly demonstrated. The ground motion amplifi cation maps for various spectral periods and rock ground motion intensity levels are also generated to be used in the regional seismic hazard assessment for infrastructure. It is found that ground motions for long periods are substantially amplifi ed in the center of the delta, while those for short periods are de-amplifi ed when input rock motions are large.展开更多
From its first description in antiquity, the place of cryptophthalmos in the history of medical genetics is briefly set out until, in the twentieth century, this rare constellation of multiple congenital malformations...From its first description in antiquity, the place of cryptophthalmos in the history of medical genetics is briefly set out until, in the twentieth century, this rare constellation of multiple congenital malformations of which cryptophthalmos is the most striking, even though not obligatory, component, was identified as an inherited autosomal recessive condition. It was given the name of Fraser syndrome and mutant alleles of the genes FRAS1, FREM2 and GRIP1 were identified as being responsible for a proportion of cases. In the remainder of cases, it may be supposed that mutant alleles of other genes, as yet unidentified, are responsible. In general, this association of multiple disparate malformations in an autosomal recessive condition may be expected to throw light on important aspects of gene action in embryogenesis. An aspect of medical genetics, which has become important with respect to the condition, is antenatal diagnosis with the prospect of abortion of affected fetuses.展开更多
Fraser syndrome is a rare autosomal recessive multisystem disorder with a reported incidence of 0.043 per 10,000 live born infants and 1.1 in 10,000 stillbirths[1]. The condition is characterised by cryptophthalmos, c...Fraser syndrome is a rare autosomal recessive multisystem disorder with a reported incidence of 0.043 per 10,000 live born infants and 1.1 in 10,000 stillbirths[1]. The condition is characterised by cryptophthalmos, cutaneous syndactyly, laryngeal and genitourinary malformations, craniofacial dysmorphism, orofacial clefting, musculoskeletal anomalies and mental retardation. The diagnosis can be made on prenatal scans, post natal clinical examination or on autopsy findings. We present a case of Fraser syndrome and review of the ocular manifestations of this condition.展开更多
Fraser syndrome is a rare malformative genetic syndrome whose main manifestations are cryptophthalmia, syndactyly, laryngeal atresia and urogenital malformations. We report the observation of a newborn from a non-cons...Fraser syndrome is a rare malformative genetic syndrome whose main manifestations are cryptophthalmia, syndactyly, laryngeal atresia and urogenital malformations. We report the observation of a newborn from a non-consanguineous marriage, admitted to the neonatology and neonatal intensive care unit at Day 1 of life for a poly-malformative syndrome. Clinically, the newborn presented with bilateral anophthalmia, cleft palate, dysmorphic facies with a rounded forehead, hypertelorism, micrognathia, low-set ears and a short neck, syndactility and bilateral cryptorchidism. Trans fontanellar ultrasound revealed tri ventricular hydrocephalus. Cerebral MRI angiography showed malformative tri-ventricular hydrocephalus, hypoplasia of the brainstem and cerebellum, and poly-microgyria. Transthoracic and renal ultrasonography were unremarkable, and the chest X-ray was normal. The authors discuss the malformative clinical and para-clinical aspects of this syndrome, multidisciplinary management and the importance of prenatal diagnosis.展开更多
The fluvial-tidal transition(FTT)is a complex depositional zone,where fluvial flow is modified by tides as rivers approach a receiving marine basin.Variations in the relative importance of tidal versus fluvial process...The fluvial-tidal transition(FTT)is a complex depositional zone,where fluvial flow is modified by tides as rivers approach a receiving marine basin.Variations in the relative importance of tidal versus fluvial processes lead to a distinctive distribution of sediments that accumulate on channel bars.The FTT generally consists of three broad zones:(1)a freshwater-tidal zone;(2)a tidally influenced freshwater to brackish-water transition:and(3)a zone of relatively sustained brackish-water conditions with stronger tides.A very common type of deposit through the fluvial-tidal transition,especially on the margins of migrating channels,is inclined heterolithic stratification(IHS).At present,a detailed account of changes in the character of IHS across the FIT of a paleo-channel system has not been reported,although a number of modern examples have been documented.To fill this gap,we quantitatively assess the sedimentology and ichnology of IHS from seven cored intervals in three geographic areas situated within the youngest paleovalley("A"Valley)in the Lower Cretaceous McMurray Formation of Alberta.Canada.We compare the data to trends defined along the FTT in the present-day Fraser River in British Columbia.Canada to interpret paleo-depositional position in the ancient fluvial-tidal channels.Analysis determined that the mean mudstone thickness is 8.2 cm in the southern study area(SA).Mean thickness increases to 11 cm in the central study area(CA),and decreases again to 4.4 cm in the northern study area(NA).The proportion of mudstone is 31%in SA,44%in CA,and 27%in NA.Thicknessweighted mean bioturbation intensity in sands varied from 0.29 in SA and CA.to 0.28 in NA.On the other hand,thickness-weighted mean bioturbation intensity(Bl)in mudstone increases from 1.46 in SA.to 1.77 in CA.and is 1.94 in NA.The ichnological diversity also increased from south to north.Sedimentological results show sinilar trends to those of the Fraser River,enabling the identification of a freshwater to brackish-water transition zone with tidal influence.The interpreted position of the transition is underpinned by the bioturbation intensity and trace-fossil diversity trends,indicating periodic brackish-water conditions throughout SA in the McMurray Formation during low river flow conditions.Together,these data suggest that a broad FTT existed in the"A"Valley,with fluvial-dominated channels to the south that experienced seasonal brackish-water inundation during base flow,and channels experiencing increasing brackish-water influence lying further north towards a turbidity maximun zone.The FIT zone appears to have extended for several hundred kilometers fron south to north.Based on the sedimentological and ichnological data,as well as estimations of lateral accretion rates,we refute the colmonly applied Mississippi River depositional analogue for McMurray Formation channels.Rather,we show that while not a perfect fit,the tidally influenced Fraser River shows much greater agreement with the depositional character recorded in McMurray Formation IHS.Future work on the McMurray system should focus on characterizing tide-dominatecl deltaic and estuarine systems,such as the Ganges-Brahmaputra,and on forward-modeling the evolution of tide-dominated and tideinfluenced river systems.展开更多
基金2018 Research Fund(1.170059.01)of UNIST(Ulsan National Institute of Science and Technology)the National Research Foundation of Korea(NRF)with a grant from the Korean government(MSIT)(NRF-2017R1C1B5074430)
文摘The Fraser River delta in Greater Vancouver, Canada consists of deep soft deposits of silts and clays, and it is well known that the deep soil deposits can amplify the low frequency contents of ground motions. This study aims to investigate the eff ects of deep soil deposits in the delta on ground motion amplifi cations by using thorough site response simulations that account for the full soil profi les and a suite of recorded ground motions that covers a wide range of intensity levels. Based on both equivalent-linear and nonlinear site response simulations, the eff ects of soil depth (represented by natural period of the soil, TS) on ground motion amplifi cations for various spectral periods are clearly demonstrated. The ground motion amplifi cation maps for various spectral periods and rock ground motion intensity levels are also generated to be used in the regional seismic hazard assessment for infrastructure. It is found that ground motions for long periods are substantially amplifi ed in the center of the delta, while those for short periods are de-amplifi ed when input rock motions are large.
文摘From its first description in antiquity, the place of cryptophthalmos in the history of medical genetics is briefly set out until, in the twentieth century, this rare constellation of multiple congenital malformations of which cryptophthalmos is the most striking, even though not obligatory, component, was identified as an inherited autosomal recessive condition. It was given the name of Fraser syndrome and mutant alleles of the genes FRAS1, FREM2 and GRIP1 were identified as being responsible for a proportion of cases. In the remainder of cases, it may be supposed that mutant alleles of other genes, as yet unidentified, are responsible. In general, this association of multiple disparate malformations in an autosomal recessive condition may be expected to throw light on important aspects of gene action in embryogenesis. An aspect of medical genetics, which has become important with respect to the condition, is antenatal diagnosis with the prospect of abortion of affected fetuses.
文摘Fraser syndrome is a rare autosomal recessive multisystem disorder with a reported incidence of 0.043 per 10,000 live born infants and 1.1 in 10,000 stillbirths[1]. The condition is characterised by cryptophthalmos, cutaneous syndactyly, laryngeal and genitourinary malformations, craniofacial dysmorphism, orofacial clefting, musculoskeletal anomalies and mental retardation. The diagnosis can be made on prenatal scans, post natal clinical examination or on autopsy findings. We present a case of Fraser syndrome and review of the ocular manifestations of this condition.
文摘Fraser syndrome is a rare malformative genetic syndrome whose main manifestations are cryptophthalmia, syndactyly, laryngeal atresia and urogenital malformations. We report the observation of a newborn from a non-consanguineous marriage, admitted to the neonatology and neonatal intensive care unit at Day 1 of life for a poly-malformative syndrome. Clinically, the newborn presented with bilateral anophthalmia, cleft palate, dysmorphic facies with a rounded forehead, hypertelorism, micrognathia, low-set ears and a short neck, syndactility and bilateral cryptorchidism. Trans fontanellar ultrasound revealed tri ventricular hydrocephalus. Cerebral MRI angiography showed malformative tri-ventricular hydrocephalus, hypoplasia of the brainstem and cerebellum, and poly-microgyria. Transthoracic and renal ultrasonography were unremarkable, and the chest X-ray was normal. The authors discuss the malformative clinical and para-clinical aspects of this syndrome, multidisciplinary management and the importance of prenatal diagnosis.
基金The Natural Sciences and Engineering Research Council of Canada and Carbon Management Canada funded the rock record portion of this study
文摘The fluvial-tidal transition(FTT)is a complex depositional zone,where fluvial flow is modified by tides as rivers approach a receiving marine basin.Variations in the relative importance of tidal versus fluvial processes lead to a distinctive distribution of sediments that accumulate on channel bars.The FTT generally consists of three broad zones:(1)a freshwater-tidal zone;(2)a tidally influenced freshwater to brackish-water transition:and(3)a zone of relatively sustained brackish-water conditions with stronger tides.A very common type of deposit through the fluvial-tidal transition,especially on the margins of migrating channels,is inclined heterolithic stratification(IHS).At present,a detailed account of changes in the character of IHS across the FIT of a paleo-channel system has not been reported,although a number of modern examples have been documented.To fill this gap,we quantitatively assess the sedimentology and ichnology of IHS from seven cored intervals in three geographic areas situated within the youngest paleovalley("A"Valley)in the Lower Cretaceous McMurray Formation of Alberta.Canada.We compare the data to trends defined along the FTT in the present-day Fraser River in British Columbia.Canada to interpret paleo-depositional position in the ancient fluvial-tidal channels.Analysis determined that the mean mudstone thickness is 8.2 cm in the southern study area(SA).Mean thickness increases to 11 cm in the central study area(CA),and decreases again to 4.4 cm in the northern study area(NA).The proportion of mudstone is 31%in SA,44%in CA,and 27%in NA.Thicknessweighted mean bioturbation intensity in sands varied from 0.29 in SA and CA.to 0.28 in NA.On the other hand,thickness-weighted mean bioturbation intensity(Bl)in mudstone increases from 1.46 in SA.to 1.77 in CA.and is 1.94 in NA.The ichnological diversity also increased from south to north.Sedimentological results show sinilar trends to those of the Fraser River,enabling the identification of a freshwater to brackish-water transition zone with tidal influence.The interpreted position of the transition is underpinned by the bioturbation intensity and trace-fossil diversity trends,indicating periodic brackish-water conditions throughout SA in the McMurray Formation during low river flow conditions.Together,these data suggest that a broad FTT existed in the"A"Valley,with fluvial-dominated channels to the south that experienced seasonal brackish-water inundation during base flow,and channels experiencing increasing brackish-water influence lying further north towards a turbidity maximun zone.The FIT zone appears to have extended for several hundred kilometers fron south to north.Based on the sedimentological and ichnological data,as well as estimations of lateral accretion rates,we refute the colmonly applied Mississippi River depositional analogue for McMurray Formation channels.Rather,we show that while not a perfect fit,the tidally influenced Fraser River shows much greater agreement with the depositional character recorded in McMurray Formation IHS.Future work on the McMurray system should focus on characterizing tide-dominatecl deltaic and estuarine systems,such as the Ganges-Brahmaputra,and on forward-modeling the evolution of tide-dominated and tideinfluenced river systems.
