10 research outputs found
Provenance Analysis of the Ochoco Basin, Central Oregon: A Window Into the Late Cretaceous Paleogeography of the Northern U.S. Cordillera
Cretaceous forearc strata of the Ochoco basin in central Oregon may preserve a record of regional transpression, magmatism, and mountain building within the Late Cretaceous Cordillera. Given the volume of material that must have been eroded from the Sierra Nevada and Idaho batholith to result in modern exposures of mid- and deep-crustal rocks, Cretaceous forearc basins have the potential to preserve a record of arc magmatism no longer preserved within the arc, if forearc sediment can be confidently linked to sources. Paleogeographic models for mid-Cretaceous time indicate that the Blue Mountains and the Ochoco sedimentary overlap succession experienced postdepositional, coast-parallel, dextral translation of less than 400 km or as much as 1700 km. Our detailed provenance study of the Ochoco basin and comparison of Ochoco basin provenance with that of the Hornbrook Formation, Great Valley Group, and Methow basin test paleogeographic models and the potential extent of Cretaceous forearc deposition. Deposition of Ochoco strata was largely Late Cretaceous, from Albian through at least Santonian time (ca. 113â86 Ma and younger), rather than AlbianâCenomanian (ca. 113â94 Ma). Provenance characteristics of the Ochoco basin are consistent with northern U.S. Cordilleran sources, and Ochoco strata may represent the destination of much of the mid- to Late Cretaceous Idaho arc that was intruded and eroded during and following rapid transpression along the western Idaho shear zone. Our provenance results suggest that the Hornbrook Formation and Ochoco basin formed two sides of the same depositional system, which may have been linked to the Great Valley Group to the south by Coniacian time, but was not connected to the Methow basin. These results limit northward displacement of the Ochoco basin to less than 400 km relative to the North American craton, and suggest that the anomalously shallow paleomagnetic inclinations may result from significant inclination error, rather than deposition at low latitudes. Our results demonstrate that detailed provenance analysis of forearc strata complements the incomplete record of arc magmatism and tectonics preserved in bedrock exposures, and permits improved understanding of Late Cretaceous Cordilleran paleogeography
The views and experiences of suicidal children and young people of mental health support services: A meta-ethnography.
Background: Suicide is amongst the leading causes of death in young people globally and a health priority worldwide. For children and young people (CYP) attempting or considering suicide there is no agreed treatment model. Development of treatment models should be informed by the views and experiences of CYP using services. Methods: Meta-ethnography was used to systematically identify and synthesise studies reporting the views of CYP who used mental health services following suicidal behaviour. Relevant studies were quality appraised. First order (participants) and second order (original author) data were translated to identify common and disconfirming themes and concepts. Translated findings were synthesised and led to a new hypothesis supported by additional âlinguistic analysisâ of texts to construct a novel third order line-of-argument. Results: Four studies conducted since 2006 in three countries involving 44 young people aged 11-24 years were synthesised. Translation revealed that suicidal CYP do not know where or how to access help, they cannot access help directly and when seen by mental health practitioners they do not feel listened to. Line-of-argument synthesis identified a silence around suicidality within the conversations CYP have with mental health practitioners and within academic research reporting. Use of the term âself-harmâ to encompass suicidal behaviours potentially contributes to this silence by avoiding the word âsuicideâ. Conclusions: CYP who are suicidal need to have easy access to mental health services. When using services, they want to feel listened to and have suicidal feelings acknowledged. This involves professionals referring explicitly to suicide not just self-harm
Controls on Sedimentation and Cyclicity of the Boquillas and Equivalent Eagle Ford Formation from Detailed Outcrop Studies of Western and Central Texas, USA
Facies of the Boquillas and equivalent Eagle Ford Formation can be assigned to two associations: a hydrodynamically recycled association and a pelagic association. The hydrodynamically recycled association is composed of lenticular to continuous cross-laminated lime packstoneâgrainstone, heterolithic facies, and intraclastic grainstone conglomerate with intercalated calcareous mudrock. Sharp bedding contacts, abundant scours, ripple cross-lamination, oscillatory-current indicators, hummocky cross-bedding, and rounded clasts indicate recycling of the bottom sediments by storms and bottom currents above storm wave base (SWB). The pelagic association is composed of continuous lime packstone to grainstone and chalk beds with intercalated calcareous mudrock. Gradational contacts and planar lamination indicate dominant deposition by pelagic rain, but scour surfaces, coarse-fine alternations, and ripple cross-laminae indicate the influence of bottom currents below SWB.
Vertical shifts between the hydrodynamically recycled association, interpreted to represent storm agitation of the seafloor during falls in sea level, alternate with the pelagic association and define four sequence boundaries and three depositional sequences with a lower-order periodicity (third-order periodicity, ca. average 2.4 My). Sequence boundaries correspond approximately to member boundaries recognized by gamma-ray profiles. Spectral analysis reveals higher-frequency mudrockâcarbonate cycles prominent in the pelagic association, likely resulting from Milankovitch climate forcing of planktonic carbonate productivity versus clay flux. Comparison of gamma-corrected spectra with absolute age constraints reveals that the Ernst Tinaja section (in Big Bend National Park) is less than 28% complete. This is interpreted to result from abundant depositional hiatuses and erosional gaps that occur at the bed scale and at member boundaries within and bounding the Eagle Ford Formation.
We demonstrate that deep-marine pelagic deposits in epicratonic settings may be subject to a complex interaction of depositional processes including pelagic rain and recycling by bottom currents and wave-generated currents modulated by low-frequency sea-level fluctuation and high-frequency fluctuations in sediment supply
Investigation of Drought Intensity and Periodicity in South Texas using Chemical and Biological Records in Bat Guano Cores
Studies of bat guano deposits have indicated that chemical and isotopic variations recorded in the guano record can be used to examine historical variations in climate. Bracken Bat Cave in south-central Texas hosts a large bat colony that is thought to have inhabited the cave for many hundreds of years. Recent geophysical surveys suggest that guano deposits as thick as 108 ft (33 m) may be present in some areas of the cave. This study examined the potential use of the Bracken Bat Cave guano deposits to develop a robust proxy for climate change and drought history in south Texas.
Approximately 24 ft (7 m) of guano core samples were collected from Bracken Bat Cave during three sampling campaigns in early 2016. The guano cores revealed distinct physical and compositional layering. For example, guano pellets along with insect and bone detritus enabled identification of more than twenty distinct layer sequences within a 9 ft (2.7 m) vertical section.
Chemical, isotopic, and mineralogical analyses were conducted on sample isolates. Radiocarbon (14C) and stable isotopic data (2H/1H, 13C/12C, 15N/14N), along with other supporting chemical data, have been used to establish age and chemical signatures associated with core sample depths and stratigraphic layers. Contrary to initial expectations, the sampled areas appear to represent guano deposition over decades rather than centuries according to isotope data correlated with layer sequences, which are thought to represent annual cycles.
The time frame of deposition can be correlated with historical local weather data. This allows evaluation of the utility of guano core in evaluating short-term and relatively recent weather patterns. The success of the correlation of chemical and isotopic variations to historical weather data of known periods of drought dictates whether longer guano core records may be used to ascertain frequency and duration of historical â and possible prehistorical â periods of drought that predate other conventional climate records
International eDelphi Study to Reach Consensus on the Methotrexate Dosing Regimen in Patients with Psoriasis
Importance: A clear dosing regimen for methotrexate in psoriasis is lacking, and this might lead to a suboptimal treatment. Because methotrexate is affordable and globally available, a uniform dosing regimen could potentially optimize the treatment of patients with psoriasis worldwide. Objective: To reach international consensus among psoriasis experts on a uniform dosing regimen for treatment with methotrexate in adult and pediatric patients with psoriasis and identify potential future research topics. Design, Setting, and Participants: Between September 2020 and March 2021, a survey study with a modified eDelphi procedure that was developed and distributed by the Amsterdam University Medical Center and completed by 180 participants worldwide (55 [30.6%] resided in non-Western countries) was conducted in 3 rounds. The proposals on which no consensus was reached were discussed in a conference meeting (June 2021). Participants voted on 21 proposals with a 9-point scale (1-3 disagree, 4-6 neither agree nor disagree, 7-9 agree) and were recruited through the Skin Inflammation and Psoriasis International Network and European Academy of Dermatology and Venereology in June 2020. Apart from being a dermatologist/dermatology resident, there were no specific criteria for participation in the survey. The participants worked mainly at a university hospital (97 [53.9%]) and were experienced in treating patients with psoriasis with methotrexate (163 [91.6%] had more than 10 years of experience). Main Outcomes and Measures: In a survey with eDelphi procedure, we tried to reach consensus on 21 proposals. Consensus was defined as less than 15% voting disagree (1-3). For the consensus meeting, consensus was defined as less than 30% voting disagree. Results: Of 251 participants, 180 (71.7%) completed all 3 survey rounds, and 58 participants (23.1%) joined the conference meeting. Consensus was achieved on 11 proposals in round 1, 3 proposals in round 2, and 2 proposals in round 3. In the consensus meeting, consensus was achieved on 4 proposals. More research is needed, especially for the proposals on folic acid and the dosing of methotrexate for treating subpopulations such as children and vulnerable patients. Conclusions and Relevance: In this eDelphi consensus study, consensus was reached on 20 of 21 proposals involving methotrexate dosing in patients with psoriasis. This consensus may potentially be used to harmonize the treatment with methotrexate in patients with psoriasis.
International eDelphi Study to Reach Consensus on the Methotrexate Dosing Regimen in Patients With Psoriasis
Abstract
Importance: A clear dosing regimen for methotrexate in psoriasis is lacking, and this might lead to a suboptimal treatment. Because methotrexate is affordable and globally available, a uniform dosing regimen could potentially optimize the treatment of patients with psoriasis worldwide.
Objective: To reach international consensus among psoriasis experts on a uniform dosing regimen for treatment with methotrexate in adult and pediatric patients with psoriasis and identify potential future research topics.
Design, setting, and participants: Between September 2020 and March 2021, a survey study with a modified eDelphi procedure that was developed and distributed by the Amsterdam University Medical Center and completed by 180 participants worldwide (55 [30.6%] resided in non-Western countries) was conducted in 3 rounds. The proposals on which no consensus was reached were discussed in a conference meeting (June 2021). Participants voted on 21 proposals with a 9-point scale (1-3 disagree, 4-6 neither agree nor disagree, 7-9 agree) and were recruited through the Skin Inflammation and Psoriasis International Network and European Academy of Dermatology and Venereology in June 2020. Apart from being a dermatologist/dermatology resident, there were no specific criteria for participation in the survey. The participants worked mainly at a university hospital (97 [53.9%]) and were experienced in treating patients with psoriasis with methotrexate (163 [91.6%] had more than 10 years of experience).
Main outcomes and measures: In a survey with eDelphi procedure, we tried to reach consensus on 21 proposals. Consensus was defined as less than 15% voting disagree (1-3). For the consensus meeting, consensus was defined as less than 30% voting disagree.
Results: Of 251 participants, 180 (71.7%) completed all 3 survey rounds, and 58 participants (23.1%) joined the conference meeting. Consensus was achieved on 11 proposals in round 1, 3 proposals in round 2, and 2 proposals in round 3. In the consensus meeting, consensus was achieved on 4 proposals. More research is needed, especially for the proposals on folic acid and the dosing of methotrexate for treating subpopulations such as children and vulnerable patients.
Conclusions and relevance: In this eDelphi consensus study, consensus was reached on 20 of 21 proposals involving methotrexate dosing in patients with psoriasis. This consensus may potentially be used to harmonize the treatment with methotrexate in patients with psoriasis