scholarly journals New insights into the genesis of pyroducts of The Galápagos islands, Ecuador

2021 ◽  
Vol 50 (1) ◽  
Author(s):  
Stephan F.J. Kempe ◽  
Greg Middleton ◽  
Aaron Addison ◽  
Theofilos Toulkeridis ◽  
Geoffrey Hoese

There has been little research on the genesis and development of pyroducts (or lava tubes) originating from Gala´pagos volcanoes. Pyroducts are responsible for the lateral, post-eruptive transport of lava because they are highly effective as thermal insulators. After eruptions terminate, these conduits often become accessible as caves. In March 2014 the 16th International Symposium on Vulcanospeleology brought a large group of vulcanospeleological specialists to the Islands. During the meeting a number of pyroducts were visited and studied in context on the island of Santa Cruz and around Isabella’s Sierra Negra volcano in the western, most active, part of the Gala´pagos. The longest of the caves, Cueva del Cascajo, about 3 km in length, was partly surveyed and nine other caves were visited. Structural features such as thickness of roof, evidence of downcutting, presence of oxbows, secondary ceilings, lavafalls, collapses and pukas were particularly studied for evidence they reveal about developmental stages of pyroducts. The resulting data show that the pyroducts were formed by "inflation" with the primary roof consisting of uninterrupted paŻhoehoe sheets. No pyroducts were identified that developed by the crusting-over of channels. The studies strongly confirm inferences drawn from other hot-spot related islands, such as Hawai’i.


2020 ◽  
pp. 67-73
Author(s):  
P.I. Tkachenko ◽  
I.I. Starchenko ◽  
S.O. Bilokon ◽  
N.V. Lokhmatova ◽  
N.P. Bilokon ◽  
...  

The great diversity of the jaw cysts makes the issues of their diagnosis, differential diagnosis, and treatment quite important, always requiring an individual approach, given the features of each clinical case. Although the jaw cysts were first mentioned by Scultetus in 1654, the researchers still have different views on the semiotics and classifying individual nosological forms and, consequently, on choosing treatment methods, preventing possible complications and recurrences, and making prognosis. Asymptomatic clinical course and absence of characteristic clear clinical manifestations of the jaw cysts and similarity of their signs at separate developmental stages regardless of the nosological form and origin site make this pathology relevant in the practice of maxillofacial surgery. Traumatic and aneurysmal pseudocysts are common in the nomenclature of tumor-like formations of the jaws. The paper is concerned with the etiology and pathogenesis, clinical morphological features, and modes of treatment of traumatic and aneurysmal jaw cysts, based on the generalization of the findings of the scientific researches, to emphasize the above nosological forms to the medical community. The study encompasses a thorough analysis of the fundamental scientific works and publications in periodicals on the above issues. The clinical part of the study concerned a comprehensive examination of 46 children with traumatic and aneurysmal jaw cysts who received treatment at the surgical unit of the Poltava Municipal Children’s Clinical Hospital during the period of 5 years. In addition, 8 adult patients with traumatic cysts were examined and received outpatient treatment at the Department’s clinic. Common clinical and additional examination methods, diagnostic puncture, EOD, radiography, CT, and MRI were used to make the clinical diagnosis in serious cases. The microscopic structure of the specimens made from the postoperative material using conventional techniques was studied. During 2014-2019, 46 children with non-odontogenic jaw cysts (NJC) were treated at the Department of Children’s Oral Surgery, including 24 patients (52.2%) with traumatic cysts (TC) and 15 patients (32.6%) with aneurysmal cysts (AC). That is, TC and AC accounted for 39 cases (84.8%) of NJC. At the same time, while the general age of patients with NJC ranged from 5 to 15 years, TC and AC were most common in children aged 10-15 years, which is consistent with other researchers’ data, who observed the highest incidence in puberty. 25 (64,1%) boys and 14 girls (35.9%) have been involved in the study. Generalized statistical analysis revealed that traumatic cysts accounted for 52.2% of children, 32.6% for aneurysmal and 15.2% for other types of non-odontogenic jaw cysts. The patients were predominantly males, and even trauma in the past medical history did not always correspond to and confirm the type of cystic formation. The presented material suggests a rather unclear diagnostic “boundary” between traumatic and aneurysmal cysts, when, in fact, the main differential diagnostic criterion is a carefully gathered anamnesis, even at the prehospital stage. The given material can be the basis for further in-depth scientific and practical studies on immunohistochemical structural features of traumatic and aneurysmal jaw cysts.



2010 ◽  
Vol 138 (1) ◽  
pp. 6-12.e2 ◽  
Author(s):  
Jean–Michel Pawlotsky ◽  
Laurence Cocquerel ◽  
David Durantel ◽  
Dimitri Lavillette ◽  
Hervé Lerat ◽  
...  


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