2,066 research outputs found
Subretinal lavage to prevent persistent subretinal fluid after rhegmatogenous retinal detachment surgery : a study of feasibility and safety
Land Otter people and Tlingit shamans
Der im 18. Jahrhundert an der Nordwestküste einsetzende maritime Pelzhandel zog im Kulturraum der Tlingit nicht nur eine ökonomische Neurorientierung nach sich, sondern veränderte auch die Denkbilder im Bezug auf die schamanischen Hilfsgeister: Land-otter-people, als spirituell einflussreichste aller metaphysischen Wesenheiten und die bedeutendsten Hilfsgeister der Tlingit-Schamaninnen/Schamanen, erfuhren einen fundamentalen Bedeutungswandel ihrer symbolischen Zuschreibungen.
Wurden Land-otter-people noch vor Ankunft der europäischen Pelzhandelnden als meist benevolente spirituelle Entitäten wahrgenommen, änderte sich die Konstruktion ihrer symbolischen Identität grundlegend, als sich die Tlingit am Fellhandel beteiligten und Seeotter – im 18. Jahrhundert hochbegehrte Pelztiere – mit großen Gewinnen bejagten.
Die neue Prosperität blieb, meiner ethnopsychotherapeutischen Interpretation nach, allerdings nicht ohne innerpsychische Konsequenzen: Da im Realitätskonstrukt der Tlingit keine Differenzierung zwischen Otter als reale, zoologische Tiere und ihren transzendenten Pendants (Land-otter-people) existierte, repräsentierte das Töten der Otter, welche in der Kosmovision als sakrosankte schamanische Wesen angesehen wurden einen Tabubruch.
Der infolge der Bejagung der Otter im kollektiven Unbewussten entstandene Konflikt stellte einen polarisierten Prozess zwischen dem Wunsch nach materiellem Vermögen (resultierend aus dem Otterpelzverkauf) und dem Wunsch nach Wahrung der immateriellen Wissensinhalte (Achten der Integrität und Unverletzlichkeit der hochsakralen Otter) dar, wobei als Konfliktlösung eine elementare Umgestaltung der symbolischen Identität von Land-otter-people gewählt wurde.
Im kollektiven Unbewussten der Tlingit hatten Land-otter-people somit eine Identitätsneukonstruktion von bene- zu malevolenten spirituellen Entitäten erfahren, wodurch ihre zoologischen Äquivalente (Otter) von nun an ohne Schuldgefühle bejagt und getötet werden konnten. Um die kollektiven Schuldgefühle hinsichtlich des begangenen Tabubruchs bewältigen zu können, bedurfte es demnach aus psychohygienischen Gründen einer innerpsychischen Legitimation.In the 18th century, the maritime fur trade on the Pacific Northwest coast not only brought changes concerning the native economy of the Tlingit but also altered the approach towards their shamanic spirits: Land otter people as the single most powerful supernatural beings in Tlingit universe and by far the most potent helping spirits of any Tlingit shaman underwent a radical revision.
Land otter people had been regarded as mostly benevolent spiritual entities, yet this attitude changed drastically once the Tlingit got involved into the fur trade. Since the sea otter represented a highly coveted fur bearing animal, the skilled Tlingit hunters were able to make large profits.
However, this new prosperity didn’t come without psychological implications: Since Tlingit belief made no distinction between land otter people as spiritual beings and their biological counterparts (otters), the killing of otters – as sacrosanct and sacred shamanic spirits – represented a breach of taboo. Thus the consequent conflict in native collective unconscious – as to observe the integrity of the sacred otter and to partake in the new wealth – resulted in an evolving hostile approach towards land otter people.
From now on they were seen as extremely malevolent creatures that could cause mental distress and actual maladies. Moreover, their ability to transform from animal to human form at will, combined with their eagerness to metamorphose humans into their own kind, raised fear and terror among the Tlingit. As a consequence, hunting and killing of otter was for the Tlingit now easy to achieve without remorse
Paleo- stress and strain rates in an intra-arc strike-slip fault, Sierra Nevada, California
Structures and microstructures of the Proto-Kern
Canyon fault (PKCF), a 130-km-long dextral strike-slip
shear zone of the southern Sierra Nevada batholith,
provide constraints on displacement, flow stress, and
strain rate during arc formation. Shear strain analyses
of S-C mylonites indicate ~5 km of ductile dextral slip
along the PKCF. But field mapping and measurements
of individual plutons and metamorphic pendants show
these bodies have much more elongated aspect ratios,
of up to 1:17, within the shear zone than outside of
it. This suggests significantly higher strain and dextral
slip of up to 15 km along the highest-strain zone
of the PKCF. Petrographic observations of high-strain
igneous rocks near Lake Isabella indicate that deformation
started at temperatures of 400-450° C and continued
through cooling to ~300° C. Based on ^(40)Ar/^(39)Ar
dating of hornblende, mica, and K-feldspar, early cooling
(~20° C/m.y.) from 88-70 Ma was followed by very
slow cooling (~1° C/m.y.). These data, combined with
cross-cutting relationships, suggest that dextral ductile
shear was active from 90-86 Ma. Grain sizes of dynamically
recrystallized pure quartz mylonites in this part
of the shear zone were used to estimate flow stresses of
20-40 MPa. Applying mylonitization temperature estimates
of 400-350° C and lithostatic pressures of 350-
400 MPa (from Al-in-hbl barometry) yields paleo-strain
rates along the PKCF of 10^(-13)-10^(-15) /s. Additional
quartzite piezometry, as well as calcite piezometry on
marble mylonites, should provide further constraints on
stress and strain rates along the length and depth exposures
of this intrabatholithic shear zone
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Sensitivity of a hydraulic model to changes in channel erosion during extreme flooding
Recent research into flood modelling has primarily concentrated on the simulation of inundation flow without considering the influences of channel morphology. River channels are often represented by a simplified geometry that is implicitly assumed to remain unchanged during flood simulations. However, field evidence demonstrates that significant morphological changes can occur during floods to mobilise the boundary sediments. Despite this, the effect of channel morphology on model results has been largely unexplored. To address this issue, the impact of channel cross-section geometry and channel long-profile variability on flood dynamics is examined using an ensemble of a 1D-2D hydraulic model (LISFLOOD-FP) of the 1:2102 year recurrence interval floods in Cockermouth, UK, within an uncertainty framework. A series of hypothetical scenarios of channel morphology were constructed based on a simple velocity based model of critical entrainment. A Monte-Carlo simulation framework was used to quantify the effects of channel morphology together with variations in the channel and floodplain roughness coefficients, grain size characteristics, and critical shear stress on measures of flood inundation. The results showed that the bed elevation modifications generated by the simplistic equations reflected a good approximation of the observed patterns of spatial erosion despite its overestimation of erosion depths. The effect of uncertainty on channel long-profile variability only affected the local flood dynamics and did not significantly affect the friction sensitivity and flood inundation mapping. The results imply that hydraulic models generally do not need to account for within event morphodynamic changes of the type and magnitude modelled, as these have a negligible impact that is smaller than other uncertainties, e.g. boundary conditions. Instead morphodynamic change needs to happen over a series of events to become large enough to change the hydrodynamics of floods in supply limited gravel-bed rivers like the one used in this research
Changes in allele frequencies when different genomic coancestry matrices are used for maintaining genetic diversity
A main objective in conservation programs is to maintain genetic variability. This can be achieved using the Optimal Contributions (OC) method that optimizes the contributions of candidates to the next generation by minimizing the global coancestry. However, it has been argued that maintaining allele frequencies is also important. Different genomic coancestry matrices can be used on OC and the choice of the matrix will have an impact not only on the genetic variability maintained, but also on the change in allele frequencies. The objective of this study was to evaluate, through stochastic simulations, the genetic variability maintained and the trajectory of allele frequencies when using two different genomic coancestry matrices in OC to minimize the loss of diversity: (i) the matrix based on deviations of the observed number of alleles shared between two individuals from the expected numbers under Hardy-Weinberg equilibrium (θLH); and (ii) the matrix based on VanRaden's genomic relationship matrix (θVR). The results indicate that the use of θLH resulted in a higher genetic variability than the use of θVR. However, the use of θVR maintained allele frequencies closer to those in the base population than the use of θLH.The research leading to these results has received funding from the Ministerio de Ciencia, Innovación y Universidades, Spain (grant CGL2016-75904-C2-2-P). R. Pong-Wong is funded by the European Union’s Horizon 2020 research and innovation programme under the Grant Agreement n◦772787 (SMARTER) and the Biotechnology and Biological Sciences Research Council through Institute Strategic Programme Grant funding (BBS/E/D/30002275).Peer reviewe
Molecular Study of Preterm Birth: Genomic Ancestry, Race, and Ethnicity
BACKGROUND: Inova Translational Medicine Institute (ITMI) initiated a study to identify genomic markers predictive of preterm birth (PTB). Molecular Study of Preterm Birth evaluated ancestral reference genomes, self-reported country of birth, race and ethnicity, as well as data from the electronic medical records (EMR).
Family and racial predispositions to PTB suggest genomic characterizations may confer increased risk.
OBJECTIVE: To investigate genomic ancestry utilizing the electronic medical record, self-reported race/ethnicity, and principle component analysis to determine the molecular characterization of genomics and preterm birth
Interaction of the mu-opioid receptor with GPR177 (Wntless) inhibits Wnt secretion: potential implications for opioid dependence
BACKGROUND: Opioid agonist drugs produce analgesia. However, long-term exposure to opioid agonists may lead to opioid dependence. The analgesic and addictive properties of opioid agonist drugs are mediated primarily via the mu-opioid receptor (MOR). Opioid agonists appear to alter neuronal morphology in key brain regions implicated in the development of opioid dependence. However, the precise role of the MOR in the development of these neuronal alterations remains elusive. We hypothesize that identifying and characterizing novel MOR interacting proteins (MORIPs) may help to elucidate the underlying mechanisms involved in the development of opioid dependence. RESULTS: GPR177, the mammalian ortholog of Drosophila Wntless/Evi/Sprinter, was identified as a MORIP in a modified split ubiquitin yeast two-hybrid screen. GPR177 is an evolutionarily conserved protein that plays a critical role in mediating Wnt protein secretion from Wnt producing cells. The MOR/GPR177 interaction was validated in pulldown, coimmunoprecipitation, and colocalization studies using mammalian tissue culture cells. The interaction was also observed in rodent brain, where MOR and GPR177 were coexpressed in close spatial proximity within striatal neurons. At the cellular level, morphine treatment caused a shift in the distribution of GPR177 from cytosol to the cell surface, leading to enhanced MOR/GPR177 complex formation at the cell periphery and the inhibition of Wnt protein secretion. CONCLUSIONS: It is known that chronic morphine treatment decreases dendritic arborization and hippocampal neurogenesis, and Wnt proteins are essential for these processes. We therefore propose that the morphine-mediated MOR/GPR177 interaction may result in decreased Wnt secretion in the CNS, resulting in atrophy of dendritic arbors and decreased neurogenesis. Our results demonstrate a previously unrecognized role for GPR177 in regulating cellular response to opioid drugs
The value of genomic relationship matrices to estimate levels of inbreeding
Background
Genomic relationship matrices are used to obtain genomic inbreeding coefficients. However, there are several methodologies to compute these matrices and there is still an unresolved debate on which one provides the best estimate of inbreeding. In this study, we investigated measures of inbreeding obtained from five genomic matrices, including the Nejati-Javaremi allelic relationship matrix (FNEJ), the Li and Horvitz matrix based on excess of homozygosity (FL&H), and the VanRaden (methods 1, FVR1, and 2, FVR2) and Yang (FYAN) genomic relationship matrices. We derived expectations for each inbreeding coefficient, assuming a single locus model, and used these expectations to explain the patterns of the coefficients that were computed from thousands of single nucleotide polymorphism genotypes in a population of Iberian pigs.
Results
Except for FNEJ, the evaluated measures of inbreeding do not match with the original definitions of inbreeding coefficient of Wright (correlation) or Malécot (probability). When inbreeding coefficients are interpreted as indicators of variability (heterozygosity) that was gained or lost relative to a base population, both FNEJ and FL&H led to sensible results but this was not the case for FVR1, FVR2 and FYAN. When variability has increased relative to the base, FVR1, FVR2 and FYAN can indicate that it decreased. In fact, based on FYAN, variability is not expected to increase. When variability has decreased, FVR1 and FVR2 can indicate that it has increased. Finally, these three coefficients can indicate that more variability than that present in the base population can be lost, which is also unreasonable. The patterns for these coefficients observed in the pig population were very different, following the derived expectations. As a consequence, the rate of inbreeding depression estimated based on these inbreeding coefficients differed not only in magnitude but also in sign.
Conclusions
Genomic inbreeding coefficients obtained from the diagonal elements of genomic matrices can lead to inconsistent results in terms of gain and loss of genetic variability and inbreeding depression estimates, and thus to misleading interpretations. Although these matrices have proven to be very efficient in increasing the accuracy of genomic predictions, they do not always provide a useful measure of inbreeding.Ministerio de Ciencia e Innovación | Ref. CGL2016-75904-C2Ministerio de Ciencia e Innovación | Ref. PID2020-114426GB-C22European Commission | Ref. H2020, n. 727315Xunta de Galicia | Ref. ED431C 2020-05European Commission | Ref. H2020, SMARTER, n. 772787Biotechnology and Biological Sciences Research Council | Ref. BBS / E / D / 3000227
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Microfluidic Chemotaxis Platform for Differentiating the Roles of Soluble and Bound Amyloid-β on Microglial Accumulation
Progressive microglial accumulation at amyloid-β (Aβ) plaques is a well-established signature of the pathology of Alzheimer's disease, but how and why microglia accumulate in the vicinity of Aβ plaques is unknown. To understand the distinct roles of Aβ on microglial accumulation, we quantified microglial responses to week-long lasting gradients of soluble Aβ and patterns of surface-bound Aβ in microfluidic chemotaxis platforms. We found that human microglia chemotaxis in gradients of soluble Aβ42 was most effective at two distinct concentrations of 23 pg.mL−1 and 23 ng.mL−1 Aβ42 in monomers and oligomers. We uncovered that while the chemotaxis at higher Aβ concentrations was exclusively due to Aβ gradients, chemotaxis at lower concentrations was enhanced by Aβ-induced microglial production of MCP-1. Microglial migration was inhibited by surface-bound Aβ42 in oligomers and fibrils above 45 pg.mm−2. Better understanding of microglial migration can provide insights into the pathophysiology of senile plaques in AD
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