scholarly journals Magma-driven accommodation structures formed during sill emplacement at shallow crustal depths: The Maiden Creek sill, Henry Mountains, Utah

Geosphere ◽  
2019 ◽  
Vol 15 (4) ◽  
pp. 1368-1392
Author(s):  
Penelope I.R. Wilson ◽  
Ken J.W. McCaffrey ◽  
Robert E. Holdsworth
Keyword(s):  
Direct Evidence ◽  
Flow Direction ◽  
Critical Role ◽  
Field Studies ◽  
Magma Flow ◽  
Shear Sense ◽  
Henry Mountains ◽  
Flow Pathways ◽  
Sandstone Formation ◽  
Sill Intrusion

Abstract In areas of exceptional exposure, upper-crustal intrusions and their immediate wall rocks commonly preserve direct evidence of the emplacement, magma flow pathways, and strains associated with the intrusion process. Such excellent exposure is displayed by the Paleogene Maiden Creek intrusion—a small satellite body related to the Mount Hillers intrusive complex, Henry Mountains, Utah. An intermediate plagioclase-hornblende porphyritic magma was intruded into the Entrada Sandstone Formation at an estimated depth of ∼3 km. The southern part of the intrusion is overlain by the newly identified Maiden Creek shear zone (MCSZ): a subhorizontal, top-to-the-WNW detachment formed at the contact with the overlying sandstone country rocks. From observations of both syn-emplacement deformation and the exposed intrusion geometries, it is proposed that the southern Maiden Creek intrusion comprises westerly derived, inclined sill sheets. Host-rock sandstones were sandwiched (∼E–W constriction) between these intrusive bodies beneath the MCSZ. It is proposed that the MCSZ is a syn-emplacement magma-driven accommodation structure, with a shear sense antithetic to the magma flow direction, which played a critical role in accommodating the westerly derived sill intrusion. Our results show that inelastic syn-emplacement deformation structures, such as the MCSZ, are very important in the accommodation of magma in the subsurface. Such small structures are unlikely to be imaged by seismic-reflection surveys, highlighting the importance of detailed field studies in our understanding of intrusion geometry and emplacement mechanisms.

Direct Evidence That the MHC Class Ib Antigen Qa-2 Regulates the Fetal Immune Response to Prenatal Allotransplantation.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1200-1200
Author(s):  
Emily T. Durkin ◽  
Dina Elnaggar ◽  
Aimen F. Shaaban
Keyword(s):  
Immune Response ◽  
Peripheral Blood ◽  
Direct Evidence ◽  
Mononuclear Cells ◽  
Critical Role ◽  
Innate Immune ◽  
Donor Strain ◽  
Mhc Class Ib ◽  
Cell Dose ◽  
Class Ib

Abstract The failure to achieve durable engraftment following prenatal transplantation in immunologically normal human fetal recipients calls for a closer examination of the fetal immune response to allotransplantation. Previous studies in mice suggest that the fetal innate immune system functions as a critical barrier to allogeneic engraftment mediated by recognition of MHC class Ib antigens. We hypothesized that Qa-2 (the putative murine homolog for HLA-G) might play an essential role in the modulation of fetal immune response to prenatally transplanted allogeneic cells. To address this hypothesis, we utilized B6.K1 mice as a donor strain. B6.K1 mice are Qa-2 deficient and are congenic with wild-type B6.Ly5.2 mice. Light density mononuclear cells (LDMCs) were harvested from the livers of 14 dpc fetal B6.K1 or B6.Ly5.2 mice and transplanted into age-matched allogeneic Balb/c fetal recipients at a dose of 105 cells per fetus. Following delivery, peripheral blood chimerism was assessed serially in the recipients. Survival to weaning was similar between the groups without evidence of GVHD. At 3 weeks of age, recipients of B6.K1 cells demonstrated significantly lower peripheral blood chimerism levels than recipients of B6.Ly5.2 control cells. By 6 months of age, nearly all of the recipients of B6.K1 cells had lost their chimerism. Conversely, the chimerism levels in recipients of B6.Ly5.2 control cells remained stable suggesting that donor Qa-2 expression was essential for allograft survival. To assess the competitive capacity of the B6.K1 donor cells in the absence of immunologic disparity, B6.K1 or B6.Ly5.2 fetal liver LDMCs were transplanted into congenic B6.Ly5.1 hosts at the same cell dose per fetus. This resulted in stable long-term engraftment of the B6.K1 cells in all recipients. Chimerism levels were identical to those recipients who received B6.Ly5.2 control cells, confirming that the engraftment disparities observed in the allogeneic recipients resulted from immunologic rejection. To assess the resilience of this apparent Qa-2-dependent innate immune barrier, the allogeneic transplantation experiments were then repeated at a ten-fold higher donor cell dose (106 cells/fetus). Early chimerism levels remained significantly lower in allogeneic recipients of Qa-2 deficient cells compared to controls. However, recipients of B6.K1 cells maintained their engraftment for more than 6 months indicating that the Qa-2-dependent fetal immune barrier may be overcome with higher levels of circulating antigen. From these experiments we conclude: Host allorecognition of the class Ib antigen Qa-2 is crucial for durable engraftment following in utero transplantation; The failed engraftment of Qa-2 deficient hematopoietic cells does not result from a defective competitive engraftment capacity; Qa-2 dependent fetal immune rejection may be diminished by higher levels of early chimerism. These experiments provide direct evidence for the critical role of MHC class Ib antigens in regulation of the fetal immune response to allotransplantation. Additionally, the demonstration of reliable engraftment following transplantation of higher cell doses provides a translationally relevant approach to enhance the clinical success of prenatal transplantation in immunologically normal hosts.

scholarly journals Redirection of tumor metastasis by expression of E-selectin in vivo.

1996 ◽  
Vol 183 (2) ◽  
pp. 581-587 ◽  
Author(s):  
L Biancone ◽  
M Araki ◽  
K Araki ◽  
P Vassalli ◽  
I Stamenkovic
Keyword(s):  
Transgenic Mice ◽  
Direct Evidence ◽  
Cell Attachment ◽  
Liver Tumors ◽  
Leukocyte Adhesion ◽  
Critical Role ◽  
Promote Tumor Cell ◽  
Histologic Pattern ◽  
Alpha 1 Antitrypsin

The selectin class of adhesion molecules plays a critical role in facilitating leukocyte adhesion to and subsequent transmigration of endothelium. On this basis, selectins have been suggested to promote tumor cell attachment to endothelium, thereby facilitating metastasis of certain types of tumors, although direct evidence for such a role is lacking. To explore this hypothesis, two sets of transgenic mice were developed: TgnES, which constitutively expresses cell surface E-selectin in all tissues, under the control of the beta-actin promoter; and TgnEsol, which expresses truncated, soluble E-selectin in the liver, under the control of the alpha 1 antitrypsin promoter. B16F10 melanoma cells were stably transfected with alpha(1,3/1,4) fucosyltransferase-specific cDNA (B16F10ft), allowing them to express E-selectin ligands or with hygromycin resistance selection vector only B16F10hygro). Normal mice injected with B16F10ft and B16F10hygro and transgenic mice injected with B16F10hygro developed lung tumors exclusively. In contrast, TgnES mice injected with B16F10ft cells developed massive infiltrating liver tumors. B16F10ft cells injected into TgnEsol mice also formed liver tumors, but these grew more slowly, with a well-delineated, noninfiltrating distinct histologic pattern. These observations provide direct evidence that expression of E-selectin can redirect metastasis of tumor cells expressing appropriate ligands in vivo.

scholarly journals Eye-Tracking Causality

2017 ◽  
Vol 28 (12) ◽  
pp. 1731-1744 ◽  
Author(s):  
Tobias Gerstenberg ◽  
Matthew F. Peterson ◽  
Noah D. Goodman ◽  
David A. Lagnado ◽  
Joshua B. Tenenbaum
Keyword(s):  
Eye Movements ◽  
Eye Tracking ◽  
Direct Evidence ◽  
Critical Role ◽  
Billiard Ball ◽  
Process Theories ◽  
Causal Judgments ◽  
High Level ◽  
Counterfactual Simulation

How do people make causal judgments? What role, if any, does counterfactual simulation play? Counterfactual theories of causal judgments predict that people compare what actually happened with what would have happened if the candidate cause had been absent. Process theories predict that people focus only on what actually happened, to assess the mechanism linking candidate cause and outcome. We tracked participants’ eye movements while they judged whether one billiard ball caused another one to go through a gate or prevented it from going through. Both participants’ looking patterns and their judgments demonstrated that counterfactual simulation played a critical role. Participants simulated where the target ball would have gone if the candidate cause had been removed from the scene. The more certain participants were that the outcome would have been different, the stronger the causal judgments. These results provide the first direct evidence for spontaneous counterfactual simulation in an important domain of high-level cognition.

scholarly journals Social stress as a priming mechanism for Thermal Tolerance During a Poleward Range Shift

2018 ◽  
Author(s):  
Connor Wood ◽  
Robert N. L. Fitt ◽  
Lesley T. Lancaster
Keyword(s):  
Cold Tolerance ◽  
Social Factors ◽  
Social Stress ◽  
Social Dynamics ◽  
Critical Role ◽  
Field Studies ◽  
Range Shift ◽  
Allee Effects ◽  
Social Environments ◽  
Factors Affecting

AbstractCold tolerance plays a critical role in determining species’ geographical range limits. Previous studies have found that range shifts in response to climate warming are facilitated by cold acclimation capacities, due to increasingly colder and variable weather at high latitudes, and that cold tolerance can also be influenced by social factors. In this study we combined experiments and field studies to investigate the climatic and social factors affecting cold tolerances in range-shifting populations of the female-polymorphic damselfly Ischnura elegans in northeast Scotland. In the field, we observed both environmental (measured via habitat suitability) and social (sex ratio and density) effects on cold tolerance (CTmin). Androchrome females (male-like females) were less susceptible to beneficial social effects on cold tolerance than gynochromes (female-like females), and correspondingly, gynochrome frequency increased at colder, environmentally-limiting sites towards the range margin. Our manipulations of density in the laboratory further provide novel, experimental evidence that social interactions directly impact cold tolerance n this species. These results suggest that reciprocal effects of social environments on thermal acclimation may be an important but commonly overlooked aspect of allee effects which contribute to the formation of range margins. Moreover, our results point to a wider need to consider the role of population and social dynamics to shape both the thermal physiology of individuals and the thermal niches of species.

scholarly journals A Spatially Distributed Groundwater Metric for Describing Hydrologic Changes in a Regional Population of Wetlands North of Tampa Bay, Florida, from 1990 to 2015

2021 ◽  
Author(s):  
Geoffrey Fouad ◽  
Terrie M. Lee
Keyword(s):  
Land Surface ◽  
Flow Direction ◽  
Critical Role ◽  
Flow Equation ◽  
Wet Season ◽  
Drainage Basins ◽  
Spatially Distributed ◽  
Groundwater Condition ◽  
Regional Population ◽  
Condition Metric

Abstract A groundwater condition metric is presented and used to evaluate hydrologic changes in a regional population of wetlands in and around municipal well fields with large groundwater withdrawals. The approach compares a 26-year, monthly time series of groundwater potentiometric surfaces to light detection and ranging (LiDAR) land-surface elevations at 10,516 wetlands in a 1505-square-kilometer area. Elevation differences between the potentiometric surface and wetland land surface provide a flow direction (upward or downward) and a proxy for vertical hydraulic head difference in Darcy’s groundwater flow equation. The resulting metric quantifies the groundwater condition at a wetland through time as the potential for groundwater to discharge upward into a wetland or for water in a wetland to leak downward to recharge the underlying aquifer. The potential for wetland leakage across the regional wetland population decreased by 33% in the 13 years after cutbacks in groundwater withdrawals (2003-2015) compared to years before cutbacks (1990-2002). Inside well field properties, wetland leakage potential decreased by 24%. In the wet season month of September, wetlands with the potential to receive groundwater discharge increased to 21.6% of the regional population after cutbacks compared to 13.3% before cutbacks. When mapped across regional drainage basins, discharging wetlands formed spatial connections suggesting they play a critical role in generating streamflow.

scholarly journals ANISOTROPY OF MAGNETIC SUSCEPTIBILITY (AMS) IN VOLCANIC FORMATIONS: THEORY AND PRELIMINARY RESULTS FROM RECENT VOLCANICS OF BROADER AEGEAN.

2004 ◽  
Vol 36 (3) ◽  
pp. 1308 ◽  
Author(s):  
I. Zananiri ◽  
D. Kondopoulou
Keyword(s):  
Magnetic Susceptibility ◽  
Flow Direction ◽  
Source Region ◽  
Physical Property ◽  
Anisotropy Of Magnetic Susceptibility ◽  
Magnetic Fabric ◽  
Local Flow ◽  
Magma Flow ◽  
Preliminary Results ◽  
Scalar Properties

The anisotropy of magnetic susceptibility (AMS) is a physical property of rocks widely used in petrofabric studies and other applications. It is based on the measurement of low-field magnetic susceptibility in different directions along a sample. From this process several scalar properties arise, defining the magnitude and symmetry of the AMS ellipsoid, along with the magnetic foliation, namely the magnetic fabric. Imaging the sense of magma flow in dykes is an important task for volcanology; the magnetic fabric provides a fast and accurate way to infer this flow direction. Moreover, the AMS technique can be used in order to distinguish sills and dykes, a task that is almost impossible by using only field observations. Finally in the case of lava flows, the method can be applied to define the local flow conditions and to indicate the position of the "paleo" source region. However, this technique is quite new in Greece. Some preliminary results from volcanic formations of continental Greece and Southern Aegean are presented (Aegina, Almopia, Elatia, Gavra, Kos, Patmos, Samos, Samothraki and Santorini).

Structural controls on the emplacement and evacuation of magma from a sub-volcanic laccolith: Reyðarártindur Laccolith, SE Iceland

2021 ◽  
Author(s):  
Vincent Twomey ◽  
William McCarthy ◽  
Craig Magee
Keyword(s):  
Host Rock ◽  
Surface Deformation ◽  
Flow Direction ◽  
Volcanic Eruptions ◽  
Magma Ascent ◽  
Magma Flow ◽  
Existing Structures ◽  
Forced Folding ◽  
Deformation Patterns ◽  
Echelon Fault

<p>Laccoliths play a significant role in the transport and storage of magma in sub-volcanic systems. The construction and geometry of laccoliths can influence host rock and surface deformation patterns that may precede and provide warning of active magmatism and impending eruptions. Yet how laccolith construction and internal magma dynamics controls the location and form of magma ascent conduits (e.g., dykes and inclined sheets), which facilitate magma evacuation and may feed volcanic eruptions, remains poorly documented in natural examples.</p><p>The excellently exposed silicic, sub-volcanic Miocene Reyðarártindur Laccolith in SE Iceland offers an opportunity to investigate how magma ascent within inclined sheets, which emanated from the laccolith, related to intrusion construction and deformation in the surrounding host rock. We combine detailed structural mapping with anisotropy of magnetic susceptibility (AMS) analyses, which allow us to map magnetic rock fabrics that reflect magma flow patterns, to show that the laccolith comprises of several distinct magma lobes that intruded laterally towards the south-west. Each lobe intruded, inflated, and coalesced along a NE-SW primary axis facilitated by doming (i.e., forced folding) of the host rock. We also shown that pre-existing NNE-striking, left-stepping, en-echelon fault/fractures, as well as those generated during intrusion-induced host rock uplift, host moderately to steeply inclined rhyolitic/granophyric sheets that emanate from the lateral terminations of some flow lobes.</p><p>Based on the observed geometrical relationships between AMS fabrics and the sheet margins where magnetic foliations subparallel sheet contacts, or characterize an imbrication fabric, we suggest that magma evacuated moderately to steeply upward via these fault/fracture-controlled sheets. As these inclined sheets dip towards the laccolith, any eruptions they may have fed would have been laterally offset from the laccolith and any overlying surface deformation driven by forced folding. Our study shows that magma evacuation and ascent from laccoliths can be facilitated by inclined sheets that form at the lateral terminations of magma lobes that are spatially controlled by laccolith construction (e.g., flow direction and doming of the host rock) and the presence of pre-existing structures.</p>

Disease ecology of wild fish: Opportunities and challenges for linking infection metrics with behaviour, condition, and survival.

2021 ◽  
Author(s):  
Jacqueline M. Chapman ◽  
Lisa A. Kelly ◽  
Amy K. Teffer ◽  
Kristina M. Miller ◽  
Steven J. Cooke
Keyword(s):  
Disease Ecology ◽  
Molecular Genetic ◽  
Critical Role ◽  
Field Studies ◽  
Wild Fish ◽  
Infectious Agents ◽  
Predictive Capacity ◽  
Major Barrier ◽  
Fish Physiology ◽  
Technological Advances

Surmounting evidence supports that infectious agents play a critical role in shaping fish physiology, behaviour, and survival. The exclusion of disease-causing agents from fisheries research has resulted in major knowledge gaps that may limit the predictive capacity of ecological models. A major barrier in wild fisheries epidemiology is the logistical constraints associated with observing disease and obtaining samples from free-ranging fish, restricting the vast majority of research to laboratory studies or aquaculture facilities. For fisheries ecologists, including infectious agents can provide greater insight into observed phenomena, particularly with respect to fish physiology (e.g. metabolism), movement (e.g. migration rates), behaviour (e.g. habitat selection), personality (e.g. bold vs. shy), and survival. Here we provide a brief introduction to the current understanding of disease ecology in wild fish and describe technological advances in both epidemiology and fisheries and aquatic sciences that can be used in tandem to create comprehensive studies of disease ecology in wild fishes. Combining non-lethal sampling and molecular genetic-based identification methods with field studies creates vast opportunities for innovative study designs that have the potential to address the true complexity of aquatic ecosystems.

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