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Why Were Dinosaurs So Big?

Why were dinosaurs so big?: originally appeared on Quora: The best answer to any question. Ask a question, get a great answer. Learn from experts and access insider knowledge. You can follow Quora on Twitter, Facebook, and Google+. Answer by Marc Srour, Invertebrate Paleontologist Image by MathKnight There is actually no uncontroversial explanation for the as-of-yet unparalleled size of dinosaurs. If you look at the distribution of large sizes in dinosaurs, one distinction becomes clear: the only dinos that were small (less than 1m) were carnivorous theropods. Except for the 70 cm Fruitadens Haagarorum, no herbivorous ornithischians were small. The evolution of teeth in ornithischian lineages proceeded along very similar lines independently, and each innovation was accompanied by a bump in body size. Teeth are merely the most fossilisable sections of the digestive system. If they changed, then the rest of the animals' physiology was also changing in such a way as to enable larger body sizes, from getting larger guts to becoming quadrupedal (the first ornithischians were small and bipedal). In turn, this leads to changing ecological opportunities, feeding on different plants, being able to eat much more at once, and thus beginning the cycle of ever-growing sizes. This would then enter into a coevolutionary back-and-forth with their theropodan predators, eventually resulting in the sauropods, tyrannosaurids, and the other giants. What were the ornithischians eating to suppor...
Source: Science - The Huffington Post - Category: Science Source Type: news

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Condition:   Acromegaly Intervention:   Other: Oral manifestations Sponsor:   University Hospital, Clermont-Ferrand Recruiting
Source: ClinicalTrials.gov - Category: Research Source Type: clinical trials
Abstract Acromegaly is associated with high morbidity and elevated mortality when not adequately treated. Surgery is the first-line treatment for most patients as it is the only one that can lead to immediate cure. In patients who are not cured by surgery, treatment is currently based on a trial-and-error approach. First-generation somatostatin receptor ligands (fg-SRL) are initiated for most patients, although approximately 25% of patients present resistance to this drug class. Some biomarkers of treatment outcome are described in the literature, with the aim of categorizing patients into different groups to indi...
Source: European Journal of Endocrinology - Category: Endocrinology Authors: Tags: Eur J Endocrinol Source Type: research
ConclusionsKi-67, TOPO 2A, AIP and VEGF were expressed in over 70% of all somatotropinomas. Only Ki-67 and TOPO 2A expression correlated with tumour size and tumour invasiveness. PMID: 29334118 [PubMed - as supplied by publisher]
Source: Endokrynologia Polska - Category: Endocrinology Authors: Tags: Endokrynol Pol Source Type: research
ConclusionsActivating mutations in theABCC9 and, less commonly,KCNJ8 genes —representing the two subunits of the ATP-sensitive potassium channel—have been linked with Cantú syndrome. Interestingly, minoxidil, a well-known ATP-sensitive potassium channel agonist, can cause a similar phenotype. There is no clear explanation why activating this channel would lead to acro megaloid features or hypertrichosis. This report raises awareness for this complex condition, especially for adult or pediatric endocrinologists who might see these patients referred for evaluation of acromegaloid features or hirsutism. The...
Source: Endocrine - Category: Endocrinology Source Type: research
AbstractPurpose1) To compare the retinal, choroidal, Haller ’s layer, and Sattler’s/choriocapillaris thicknesses of untreated acromegaly patients without chiasm compression or diabetes mellitus and healthy controls. 2) To evaluate the correlations of retinal and choroidal thicknesses with serum growth hormone (GH) and insulin-like growth factor 1 (IGF) b urden.MethodsThis prospective, case-control study included 27 untreated acromegaly patients and 27 sex-matched and age-matched controls. Subfoveal choroidal, Haller ’s layer and Sattler’s/choriocapillaris thicknesses were determined by enhanced-dept...
Source: Endocrine - Category: Endocrinology Source Type: research
According to a study, published in theJournal of Clinical Endocrinology& Metabolism, premenopausal women with acromegaly have worse outcomes after transsphenoidal adenomectomy.Healio
Source: Society for Endocrinology - Category: Endocrinology Source Type: news
Conclusions Patients with treatment-naïve acromegaly are at an increased risk of developing left ventricular hypertrophy, diastolic dysfunction and systolic dysfunction than the general population.
Source: Journal of Clinical Neuroscience - Category: Neuroscience Source Type: research
AbstractSilent growth hormone adenomas (SGHA) are a rare entity of non-functioning pituitary neuroendocrine tumors. Diagnosis is invariably made post-operatively of a tumor immunopositive for GH (and Pit-1 in selected cases) but without clinical acromegaly. Mainly young females are affected, and tumors are often uncovered by investigation for headaches or oligoamenorrhea. Integration of clinical, pathological and biochemical data is required for proper diagnosis. Beside normal IGF-1 levels, a third of SGHAs displays elevated GH levels and some will eventually progress to acromegaly. Almost two-thirds will be mixed GH-prola...
Source: Pituitary - Category: Endocrinology Source Type: research
Abstract Air sacs are an important component of the avian respiratory system, and corresponding structures also were crucial for the evolution of sauropod dinosaur gigantism. Inferring the presence of air sacs in fossils so far is restricted to bones preserving internal pneumatic cavities and foramina as osteological correlates. We here present bone histological correlates for air sacs as a new potential identification tool for these elements of the respiratory system. The analysis of several avian and non-avian dinosaur samples revealed delicate fibres in secondary trabecular and secondary endosteal bone that in ...
Source: Biology Letters - Category: Biology Authors: Tags: Biol Lett Source Type: research
AbstractUnfortunately, in page 584, second column, the first sentence under the heading “Type of switch” has been published incorrectly. The complete correct sentence is given below.
Source: Journal of Endocrinological Investigation - Category: Endocrinology Source Type: research
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