scholarly journals Competition structured a Late Cretaceous megaherbivorous dinosaur assemblage

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jordan C. Mallon
Keyword(s):  
Late Cretaceous ◽  
Species Turnover ◽  
Meta Analysis ◽  
Resource Limitation ◽  
Western North America ◽  
The Family ◽  
Structural Principles ◽  
Dinosaur Park Formation ◽  
Upper Campanian

Abstract Modern megaherbivore community richness is limited by bottom-up controls, such as resource limitation and resultant dietary competition. However, the extent to which these same controls impacted the richness of fossil megaherbivore communities is poorly understood. The present study investigates the matter with reference to the megaherbivorous dinosaur assemblage from the middle to upper Campanian Dinosaur Park Formation of Alberta, Canada. Using a meta-analysis of 21 ecomorphological variables measured across 14 genera, contemporaneous taxa are demonstrably well-separated in ecomorphospace at the family/subfamily level. Moreover, this pattern is persistent through the approximately 1.5 Myr timespan of the formation, despite continual species turnover, indicative of underlying structural principles imposed by long-term ecological competition. After considering the implications of ecomorphology for megaherbivorous dinosaur diet, it is concluded that competition structured comparable megaherbivorous dinosaur communities throughout the Late Cretaceous of western North America.

An ornithurine bird coracoid from the Late Cretaceous of Alberta, Canada

2020 ◽  
pp. 1-7
Author(s):  
Sydney R. Mohr ◽  
John H. Acorn ◽  
Gregory F. Funston ◽  
Philip J. Currie
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Ct Scans ◽  
Micro Ct ◽  
Internal Structures ◽  
Postcranial Remains ◽  
Dinosaur Park Formation ◽  
Upper Campanian

The Cretaceous birds of Alberta are poorly known, as skeletal elements are rare and typically consist of fragmentary postcranial remains. A partial avian coracoid from the upper Campanian Dinosaur Park Formation of Alberta, Canada, can be referred to the Ornithurae, and is referred to here as Ornithurine G (cf. Cimolopteryx). Its structure is similar to previously described ornithurine coracoids from Alberta and other localities in North America, particularly those belonging to the genus Cimolopteryx. A comparison of these elements indicates that the new coracoid is distinct; however, its preservation prevents complete diagnosis. As other Cimolopteryx are Maastrichtian in age, Ornithurine G (cf. Cimolopteryx) also represents the earliest occurrence of a Cimolopteryx-like anatomy. A pneumatized coracoid is a diagnostic trait of Neornithes, identified by the presence of a pneumatic foramen. Ornithurine G (cf. Cimolopteryx) does not preserve this feature. CT and micro-CT scans of both pneumatic and apneumatic coracoids of modern birds show similar internal structures to Ornithurine G (cf. Cimolopteryx), indicating that pneumaticity of the coracoid cannot be determined in the absence of an external pneumatic foramen. A comparison between members of Cimolopterygidae, including Cimolopteryx and Lamarqueavis, raises questions about the assignment of Lamarqueavis to the Cimolopterygidae, and the validity of this family as a whole.

Family-based Prevention of Offending: A Meta-analysis

2003 ◽  
Vol 36 (2) ◽  
pp. 127-151 ◽  
Author(s):  
David P Farrington ◽  
Brandon C Welsh
Keyword(s):  
Outcome Measure ◽  
Meta Analysis ◽  
Child Behaviour ◽  
Control Group ◽  
Costs And Benefits ◽  
Weighted Mean ◽  
The Family ◽  
Term Evaluation ◽  
Family Based

This paper presents a review and meta-analysis of the effectiveness of family-based crime prevention programs.Programs were included in this review if (a)the family was the focus of the intervention,(b)there was an outcome measure of delinquency or antisocial child behaviour, (c)the evaluation used a randomised or well controlled experiment and (d)the original sample size was at least 50 persons.Forty evaluations were found that met the criteria for inclusion.In general,these family- based programs had desirable effects in reducing delinquency (especially) and antisocial child behaviour.Over all delinquency outcomes,the weighted mean effect size of .321 corresponds approximately to a decrease in offending from 50%in a control group to 34%in an experi- mental group.Furthermore,the effects on delinquency persisted in long- term evaluation studies.The most effective types of programs used behavioural parent training,while the least effective types were those based in schools.Home visiting,day care/preschool,home/community and multi-systematic therapy programs were generally effective.Effect sizes were greater in smaller scale studies.Research on the monetary costs and benefits of family-based programs is also reviewed.

scholarly journals Reassessment of a juvenile Daspletosaurus from the Late Cretaceous of Alberta, Canada with implications for the identification of immature tyrannosaurids

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jared T. Voris ◽  
Darla K. Zelenitsky ◽  
François Therrien ◽  
Philip J. Currie
Keyword(s):  
Late Cretaceous ◽  
Phylogenetic Analyses ◽  
Ontogenetic Stage ◽  
Ontogenetic Changes ◽  
Diagnostic Features ◽  
Taxonomic Affinity ◽  
Small Juvenile ◽  
Juvenile Individual ◽  
Dinosaur Park Formation ◽  
Upper Campanian

AbstractDaspletosaurus is a large tyrannosaurine found in upper Campanian deposits of Alberta and Montana. Although several large subadult and adult individuals of this taxon are known, only one juvenile individual, TMP 1994.143.1, has been identified. This specimen has played a key role in the idea that juvenile tyrannosaurid individuals are difficult to differentiate among species. Here the taxonomic affinity of TMP 1994.143.1 is reassessed in light of a juvenile tyrannosaurine postorbital recently discovered in the Dinosaur Park Formation of Alberta. Anatomical comparisons and phylogenetic analyses reveal that TMP 1994.143.1 is referable to the albertosaurine Gorgosaurus libratus, whereas the new postorbital belongs to a small juvenile Daspletosaurus. This taxonomic reassignment of TMP 1994.143.1 results in the juvenile ontogenetic stage of Daspletosaurus being known only from two isolated cranial elements. The new postorbital provides insights into early Daspletosaurus ontogeny, revealing that the cornual process developed earlier or faster than in other tyrannosaurids. Although some ontogenetic changes in the postorbital are found to be unique to Daspletosaurus, overall changes are most consistent with those of other large tyrannosaurines. Our results also show that diagnostic features develop early in ontogeny, such that juveniles of different tyrannosaurid species are easier to differentiate than previously thought.

Ostrich Dinosaurs from the Late Cretaceous of Western Canada

1972 ◽  
Vol 9 (4) ◽  
pp. 375-402 ◽  
Author(s):  
Dale A. Russell
Keyword(s):  
Late Cretaceous ◽  
Late Jurassic ◽  
Western Canada ◽  
Skeletal Morphology ◽  
General Body ◽  
Body Form ◽  
The Family ◽  
Secondary Palate ◽  
Highly Evolved ◽  
Upper Campanian

The family Ornithomimidae is defined on the basis of the skeletal morphology of the three genera Ornithomimus, Struthiomimus, and Dromiceiomimus known in continental strata in Alberta, which are temporally equivalent to the Upper Campanian substage. At least two genera occur in Canadian Lance (Upper Maestrichtian) equivalent strata, but cannot be identified at present. A group of more primitive ornithomimoid theropods is represented else-where by the late Jurassic Elaphrosaurus and early Cretaceous Archaeornithomimus.Ornithomimid attributes include a general body form which parallels that of the ratites; elongate forelimbs, a kinetic skull, enormous eyes, a relatively highly evolved brain, and possibly a secondary palate and supertemporal fenestrae which were nearly encircled by alae of the squamosal. A reconstruction of the myology of the thigh indicates that ornithomimids were extremely fleet, but lacked the agility characteristic of modern large ground birds. They probably subsisted on small, soft-bodied animals.

A review of nonmarine turtles from the Late Cretaceous of Alberta

2003 ◽  
Vol 40 (4) ◽  
pp. 557-571 ◽  
Author(s):  
Donald B Brinkman
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Geographic Area ◽  
Hell Creek Formation ◽  
Diversity Gradient ◽  
The Family ◽  
Group A ◽  
Dinosaur Park Formation ◽  
Milk River Formation ◽  
Horseshoe Canyon Formation

The Late Cretaceous of Alberta preserves one of the most complete records of fossil turtles within a single geographic area in North America. The Cenomanian Dunvegan Formation contains the earliest record of the family Trionychidae in North America. The Santonian Milk River Formation contains a minimum of ten taxa with Adocus, a small trionychid, and a member of the Solemydidae being the most abundant. Diversity remains high in the mid-Campanian Judith River Group. The solemyidid last occurs in the basal beds of the Judith River Group. A member of the Macrobaenidae first occurs in the Dinosaur Park Formation, the uppermost formation in the Judith River Group. Turtles diversity is low in the late Campanian lower Horseshoe Canyon Formation, and they are absent in the early Maastrichtian upper Horseshoe Canyon Formation. Diversity increases in the late Maastrichtian Scollard Formation, although it is much less than in the contemporaneous Hell Creek Formation of Montana. Two of the taxa present in the Scollard Formation, Compsemys and Plastomenus, occur in late Campanian or early Maastrichtian formations in more southerly areas of North America. The changes in turtle diversity through the Campanian and Maastrichtian are interpreted as a result of shifts in a latitudinal turtle diversity gradient resulting from changes in climate. Based on this interpretation a decrease in temperature from the mid-Campanian to early Maastrichtian, followed by a rapid increase at the beginning of the late Maastrichtian is supported.

Endoscopic Endonasal Approach for Craniopharyngiomas with Intraventricular Extension: Long-Term Outcomes and Meta-analysis

2020 ◽  
Author(s):  
Hanna Algattas ◽  
Pradeep Setty ◽  
Ezequiel Goldschmidt ◽  
Eric W. Wang ◽  
Elizabeth Tyler-Kabara ◽  
...  
Keyword(s):  
Meta Analysis ◽  
Endoscopic Endonasal Approach ◽  
Endonasal Approach ◽  
Long Term Outcomes ◽  
Endoscopic Endonasal

Mechanical thrombectomy in pediatric stroke: systematic review, individual patient data meta-analysis, and case series

2019 ◽  
Vol 24 (5) ◽  
pp. 558-571 ◽  
Author(s):  
Kartik Bhatia ◽  
Hans Kortman ◽  
Christopher Blair ◽  
Geoffrey Parker ◽  
David Brunacci ◽  
...  
Keyword(s):  
Systematic Review ◽  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Mechanical Thrombectomy ◽  
Case Reports ◽  
Meta Analysis ◽  
Case Series ◽  
Neurological Outcomes

OBJECTIVEThe role of mechanical thrombectomy in pediatric acute ischemic stroke is uncertain, despite extensive evidence of benefit in adults. The existing literature consists of several recent small single-arm cohort studies, as well as multiple prior small case series and case reports. Published reports of pediatric cases have increased markedly since 2015, after the publication of the positive trials in adults. The recent AHA/ASA Scientific Statement on this issue was informed predominantly by pre-2015 case reports and identified several knowledge gaps, including how young a child may undergo thrombectomy. A repeat systematic review and meta-analysis is warranted to help guide therapeutic decisions and address gaps in knowledge.METHODSUsing PRISMA-IPD guidelines, the authors performed a systematic review of the literature from 1999 to April 2019 and individual patient data meta-analysis, with 2 independent reviewers. An additional series of 3 cases in adolescent males from one of the authors’ centers was also included. The primary outcomes were the rate of good long-term (mRS score 0–2 at final follow-up) and short-term (reduction in NIHSS score by ≥ 8 points or NIHSS score 0–1 at up to 24 hours post-thrombectomy) neurological outcomes following mechanical thrombectomy for acute ischemic stroke in patients < 18 years of age. The secondary outcome was the rate of successful angiographic recanalization (mTICI score 2b/3).RESULTSThe authors’ review yielded 113 cases of mechanical thrombectomy in 110 pediatric patients. Although complete follow-up data are not available for all patients, 87 of 96 (90.6%) had good long-term neurological outcomes (mRS score 0–2), 55 of 79 (69.6%) had good short-term neurological outcomes, and 86 of 98 (87.8%) had successful angiographic recanalization (mTICI score 2b/3). Death occurred in 2 patients and symptomatic intracranial hemorrhage in 1 patient. Sixteen published thrombectomy cases were identified in children < 5 years of age.CONCLUSIONSMechanical thrombectomy may be considered for acute ischemic stroke due to large vessel occlusion (ICA terminus, M1, basilar artery) in patients aged 1–18 years (Level C evidence; Class IIb recommendation). The existing evidence base is likely affected by selection and publication bias. A prospective multinational registry is recommended as the next investigative step.

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