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The article discusses the selection of members for a medical mission with consideration of their unique qualities to ensure the team's wide cultural range and competence. Topics covered include the Synergy Model that pairs a nurse and patient based on common qualities, the required criteria for medical mission trip candidates, the scoring of candidates, and the team's composition. Also noted is a culturally competent team's ability to meet the needs of specific healthcare populations.

Within the uncertainties of involved astronomical and biological parameters, the Drake Equation typically predicts that there should be many exoplanets in our galaxy hosting active, communicative civilizations (ACCs). These optimistic calculations are however not supported by evidence, which is often referred to as the Fermi Paradox. Here, we elaborate on this long-standing enigma by showing the importance of planetary tectonic style for biological evolution. We summarize growing evidence that a prolonged transition from Mesoproterozoic active single lid tectonics (1.6 to 1.0 Ga) to modern plate tectonics occurred in the Neoproterozoic Era (1.0 to 0.541 Ga), which dramatically accelerated emergence and evolution of complex species. We further suggest that both continents and oceans are required for ACCs because early evolution of simple life must happen in water but late evolution of advanced life capable of creating technology must happen on land. We resolve the Fermi Paradox (1) by adding two additional terms to the Drake Equation: foc (the fraction of habitable exoplanets with significant continents and oceans) and fpt (the fraction of habitable exoplanets with significant continents and oceans that have had plate tectonics operating for at least 0.5 Ga); and (2) by demonstrating that the product of foc and fpt is very small (< 0.00003–0.002). We propose that the lack of evidence for ACCs reflects the scarcity of long-lived plate tectonics and/or continents and oceans on exoplanets with primitive life. [ABSTRACT FROM AUTHOR]

Background: Exposure to repetitive head impacts (RHI) in American football players can lead to cognitive impairment and dementia due to neurodegenerative disease, particularly chronic traumatic encephalopathy (CTE). The pathognomonic lesion of CTE consists of perivascular aggregates of hyper-phosphorylated tau in neurons at the depths of cortical sulci. However, it is unclear whether exposure to RHI accelerates amyloid-β (Aβ) plaque formation and increases the risk for Alzheimer's disease (AD). Although the Aβ neuritic plaques characteristic of AD are observed in a minority of later-stage CTE cases, diffuse plaques are more common. This study examined whether former professional and college American football players, including those with cognitive impairment and dementia, have elevated neuritic Aβ plaque density, as measured by florbetapir PET. Regardless of cognitive and functional status, elevated levels of florbetapir uptake were not expected. Methods: We examined 237 men ages 45–74, including 119 former professional (PRO) and 60 former college (COL) football players, with and without cognitive impairment and dementia, and 58 same-age men without a history of contact sports or TBI (unexposed; UE) and who denied cognitive or behavioral symptoms at telephone screening. Former players were categorized into four diagnostic groups: normal cognition, subjective memory impairment, mild cognitive impairment, and dementia. Positive florbetapir PET was defined by cortical-cerebellar average SUVR of ≥ 1.10. Multivariable linear regression and analysis of covariance (ANCOVA) compared florbetapir average SUVR across diagnostic and exposure groups. Multivariable logistic regression compared florbetapir positivity. Race, education, age, and APOE4 were covariates. Results: There were no diagnostic group differences either in florbetapir average SUVR or the proportion of elevated florbetapir uptake. Average SUVR means also did not differ between exposure groups: PRO-COL (p = 0.94, 95% C.I. = [− 0.033, 0.025]), PRO-UE (p = 0.40, 95% C.I. = [− 0.010, 0.029]), COL-UE (p = 0.36, 95% CI = [0.0004, 0.039]). Florbetapir was not significantly associated with years of football exposure, cognition, or daily functioning. Conclusions: Cognitive impairment in former American football players is not associated with PET imaging of neuritic Aβ plaque deposition. These findings are inconsistent with a neuropathological diagnosis of AD in individuals with substantial RHI exposure and have both clinical and medico-legal implications. Trial registration: NCT02798185. [ABSTRACT FROM AUTHOR]

This paper is focused on F. W. J. Schelling's view of freedom during the period of the Freiheitsschrift (1809) and related works. It is argued that the standard way this has been understood may be too simplistic. On this standard interpretation of his view, evil is made a matter of free choice by the agent, but where the choice does not concern individual actions, but the choice of the agent's essence in an atemporal act. As a result of this choice, it is argued, Schelling can then make evil imputable. By contrast, I argue that for Schelling freedom does not involve choice, but necessity, but in a way that is still internal to the agent and hence non‐coercive, and thus in a way that remains free and makes evil imputable. How Schelling comes to have this view is considered, and some responses are given to ways it might be challenged both interpretatively and philosophically. [ABSTRACT FROM AUTHOR]

Broadly similar Early to Middle Jurassic stratigraphic sequences including bimodal igneous rocks of the Sanandaj–Sirjan Zone of Iran and the Sakarya Zone of Turkey suggest that these formed in a common tectonic setting in an extensional basin that evolved from a terrestrial magmatic rift to a marine shelf and passive continental margin. Whole‐rock chemistry and Sr–Nd isotope signatures indicate derivation of mafic melts from partial melting of the subcontinental lithosphere. Decompression associated with extension led to 5%–30% partial melting of spinel–garnet lherzolite with minor involvement of continental crust, producing tholeiitic to transitional basaltic magma. Extensional basins inverted during the Mid‐Late Jurassic. These relationships suggest the Early to Middle Jurassic formation of a volcanic rifted margin on the SW Eurasian margin, similar to that of offshore Norway. [ABSTRACT FROM AUTHOR]

The article presents the discussion on Hegel's philosophy related to other philosophers such as Plato, Aristotle, Descartes, Spinoza, Kant, Schelling and Frege bringing out the nature of disagreement.

In this article, I consider how pride and anxiety can prevent us from loving the neighbour, and how Søren Kierkegaard and K.E. Løgstrup offer two different ways in which these obstacles might be overcome. For Kierkegaard, this is made possible if we stand in the right relation to God, while for Løgstrup it is made possible if we understand life as a gift. The differences and respective merits of both approaches are explored, and in particular whether Løgstrup's approach can claim to offer a secular alternative to the role that Kierkegaard gives to God's grace in making neighbour love possible. [ABSTRACT FROM AUTHOR]

The Cadomian orogeny reflects S -directed subduction on the northern margin of Greater Gondwana in Ediacaran – Cambrian time (∼600-500 Ma). It is well known from the eastern seaboard of North America, western and southern Europe, Turkey and Iran but is rarely identified in what was its backarc in N. Africa and Arabia. Here I summarize evidence for the Cadomian across ∼6500 km of Arabia and N. Africa from Oman to Morocco. The beginning of the Cadomian in Afro-Arabia cuts across and overlaps in time with earlier Neoproterozoic orogenies leading to the formation of Greater Gondwana, so emphasis is on rocks <570 Ma. Three Cadomian backarc crustal tracts or segments are identified. The eastern segment (Oman, Persian Gulf, eastern Saudi Arabia) mostly consists of buried transtensional basins with little igneous activity. The central segment was characterized by lower crust magma underplating and strong uplift along a N –S axis (Jordan) accompanied by rifting leading to deposition of thick sediments reminiscent of a passive continental margin, and strong evidence for regional metasomatism (Israel). The Zenifim passive margin is 580–610 Ma, older than our arbitrary 570 Ma limit for identifying the Cadomian but clearly post-dates terminal continental collision to form the East African Orogen and so must be related to Cadomian back-arc rifting. Along with related NE-SW trending dike swarms in NE Egypt and Jordan, the orientation of the Zenifim rifted margin, orthogonal to the Cadomian convergent margin, is another indication of strong Cadomian transtension. In contrast, the western segment (Libya, Algeria, Morocco) experienced abundant igneous activity, with evidence for this found especially far south in Libya. Recognition of the Cadomian orogeny in northern Africa provides a useful first step in breaking out distinct tectonic episodes in the ∼300 m.y. long Pan-African orogeny, at least in the north. Finally, the orthogonal relationship between older N –S orogens in the interior of Greater Gondwana and the E -W Cadomian orogen illustrates how the Neoproterozoic plate mosaic grew by subduction initiation exploiting lithospheric weaknesses along its continental margin. Ten recommendations for future research are also suggested. • The ∼550 Ma Cadomian orogeny in N. Africa and Arabia is reviewed for the first time. • N. Africa-Arabia Cadomian crosscuts older Neoproterozoic structures. • N. Afro-Arabia Cadomian is mostly transtensional basins in E, magmatic rocks in W. • Rifted continental margin offshore Israel suggests Cadomian basins lie further W. • 10 suggestions for research are provided. [ABSTRACT FROM AUTHOR]

Fieldwork teaching methodology (FTM) and active learning are effective strategies for geoscience education. However, traditional field trips require significant resources, time, physical abilities, and the expertise of teachers. In this study, we provide a supplementary virtual field trip experience by showing how different kinds of geoscience videos can be spatially organized into one digital interactive virtual environment. Here, we present the Google Earth Geoscience Video Library (GEGVL) which uses Google Earth and location-specific videos about Earth events, to create a virtual field-based learning experience. Using Google Earth, GEGVL organizes field-based videos by location and links pertinent non-field-based videos, and allows users to roam the globe in search of geoscientific videos that are pertinent to them or their students. Currently, GEGVL contains 150 videos organized into ten different geoscience disciplines: Plate Tectonics, Minerals, Structural Geology, Metamorphism, Magmatism, Hydrology, Environmental Science, Sedimentology, Paleontology, and Paleomagnetism. Despite stability challenges with Google Earth integration, results of user surveys among lower-division undergraduates show that the design logic of GEGVL is a promising virtual field-based learning organizer for increasing students' interest in and helping them learn about Earth sciences. [ABSTRACT FROM AUTHOR]

Deposits of semi-gemstones tourmaline, beryl, and garnet associated with Jurassic granites are found in the northern Sanandaj–Sirjan Zone (SaSZ) of western Iran, defining a belt that can be traced for about 400 km. Granitic magmas strongly interacted with or were derived from melts of continental crust and/or sediments. Based on morphologies, size, mineral assemblage, and contact relationships with host granite and associated metamorphic aureoles, these deposits are categorized into six types: (1) garnet in skarns, (2) tourmaline, beryl, and garnet in pegmatite and aplitic dikes, (3) disseminations and patches of tourmaline in leucogranites, (4) quartz-tourmaline veins in granite, (5) tourmaline and garnet in metamorphic aureoles, and (6) tourmaline orbicules in aplite. Tourmalines are mostly schorl and dravite, and garnets are mostly almandine, spessartine, and grossular. Tourmaline, beryl, and garnet from pegmatites in the contact aureole of Jurassic granites reflect segregations of Be, B, Mn, and Al bearing melts from the Jurassic peraluminous granites. Quartz-tourmaline veins and hydrothermal garnets in skarns reflect fluids exsolved from the surrounding metasediment and pegmatite melt. In contrast, tourmaline patches and orbicules developed from boron-rich aqueous fluids exsolved from cooling granitic magma. Distribution of semi-gemstones in the SaSZ shows that these are mostly related to pegmatites associated with Jurassic granitic intrusions. Mineral equilibrium considerations indicate that SaSZ semi-gemstones crystallized at P = 3.5–7.5 kbar (11.5–25 km deep) and temperatures of 550–650°C. SaSZ pegmatites fall in the muscovite (MS) and MS-rare element classes. They are Lithium Cesium Tantalum (LCT)-type pegmatites. Fluids responsible for gem mineralization were exsolved from cooling granite bodies and released by metamorphosed sediments. Further studies are needed to better understand the northern Sanandaj–Sirjan tourmaline–garnet–beryl semi-gemstone Province. [ABSTRACT FROM AUTHOR]

This paper deals with the issue of self-determination and agency in moral action. On the one hand, it seems that where possible, the moral agent should use their practical reason to identify what it is right for them to do, and act accordingly; on the other hand, this seems to leave little room for the agent to decide for themselves how to act, where this is often said to be a marker of freedom and how the will is exercised. In response to this difficulty, Ruth Chang has argued recently that at least some reasons themselves need to be seen as being created through an act of will. Looking at the work of Iris Murdoch, it is argued that this response is problematic. At the same time, it is also argued that Murdoch can provide a fruitful way of dealing with this problem through her account of the imagination. This gives a role to the will of the agent, not in creating reasons, but in attuning us to those reasons, thereby locating the will within practical reasoning itself and showing how the authority of the good can be made compatible with human freedom. [ABSTRACT FROM AUTHOR]

[Display omitted] • A transition from 695 Ma I-type, convergent margin magmatism in the north to 635 Ma alkalic, within magmatism in the south is recorded. • Our results thus document a chronologic and tectonic transition from synorogenic, intra-oceanic arc to post-collision within-plate magmatism in the Ediacaran. • Our results also illustrate the viability of dikes as markers of orogénesis. The tectonic evolution of the Arabian-Nubian Shield began with formation of intra-oceanic arcs followed by collisions between these in Tonian-Cryogenian time and culminated in Ediacaran continental collision to form Gondwana. We provide new insights into the middle stage of this tectonic evolution by focusing on two Neoproterozoic dike swarms of different age in northern Arabia. The 695–700 Ma Za'am dikes were emplaced about the time of collision between the Midyan and Hijaz terranes whereas the 635 Ma Bayda dikes were emplaced ∼ 60 million years after collision. These record a shift from relatively unfractionated 695 Ma arc-type magmas in the south to fractionated 635 Ma within-plate alkaline magmas in the north. Our results document mantle source and crustal evolution beneath the Midyan terrane during and after terrane accretion, revealing a tectono-magmatic transition from SSZ-type magmas accompanying arc collision to post-terrane accretion within-plate magmatism through Cryogenian time. In addition, our results confirm the potential of dike studies for reconstructing the tectono-magmatic-metallogenic evolution of orogens. [ABSTRACT FROM AUTHOR]

Garnets show wide ranges of chemical compositions and are key minerals for reconstructing the thermodynamic evolution of metamorphic terranes. The properties of garnets – including Mohs hardness ~7, lack of cleavage, vitreous luster and multiple colors – also makes them useful as semi-gemstones. Garnets are widespread accessory minerals in igneous and metamorphic rocks of western and southern Iran and are especially abundant in skarns and regional metamorphic rocks. 45 garnet deposits of western and southern Iran show six associations: (1) skarn (35 locations); (2) peraluminous granitoid and rhyolite (4 locations); (3) alkaline granite (1 location); (4) metamorphic rocks (3 locations); and (5) ophiolites (2 locations). Distinct garnet compositions are found in each association: mostly grossular-andradite in skarn, Ti-andradite in alkaline granite, almandine in peraluminous granite and volcanic rocks, almandine-grossular in metamorphic rocks and andradite- uvarovite associated with ophiolites. Western and southern Iran garnets are mostly related to skarns around Cenozoic granitoid intrusions. Ti-rich garnet formed at the expense of clinopyroxenites in alkaline igneous complexes due to alkaline metasomatism. These associations are useful for understanding garnet semi-gemstone deposits in western and southern Iran. [ABSTRACT FROM AUTHOR]

Gender inequity is widespread in academic medicine, including in the promotion, academic recognition, and compensation of female faculty. To assess whether these inequities extend to the GME intern selection process, this study examines differences in the interview scores assigned to male and female applicants at one large internal medicine residency program. Subjects include 1399 applicants who completed 3099 interviews for internship positions for the Brigham and Women's Hospital internal medicine residency in Electronic Residency Application Service (ERAS) cycles 2015–2016, 2017–2018, 2018–2019, and 2019–2020. Unadjusted and multivariable linear regressions were used to assess the simultaneous effect of applicant gender, interviewer gender, and applicant academic characteristics on pre-interview, post-interview, and change in interview scores. Our analysis included 3027 interviews (97.7%) of 1359 applicants (97.1%). There were no statistically significant differences in the interview scores assigned to female versus male applicants. This was true across pre-interview scores (difference = 0.03, P =.61), post-interview scores (difference = 0.00, P =.98), and change in interview scores (difference = 0.01, P =.24) as well as when adjusting for the baseline academic characteristics of both male and female applicants. This was also true when analyzing individual application years, individual residency tracks, and accounting for the gender of the faculty interviewers. The findings do not support the presence of gender inequity in the interview scores assigned to male and female applicants included in this study. [ABSTRACT FROM AUTHOR]

Iran is a remarkable geoscientific laboratory where the full range of processes that form and modify the continental crust can be studied. Iran's crustal nucleus formed as a magmatic arc above an S-dipping subduction zone on the northern margin of Gondwana 600–500 Ma. This nucleus rifted and drifted north to be accreted to SW Eurasia ∼250 Ma. A new, N-dipping subduction zone formed ∼100 Ma along ∼3,000 km of the SW Eurasian margin, including Iran's southern flank; this is when most of Iran's many ophiolites formed. Iran evolved as an extensional continental arc in Paleogene time (66–23 Ma) and began colliding with Arabia ∼25 Ma. Today, Iran is an example of a convergent plate margin in the early stages of continent-continent collision, with a waning magmatic arc behind (north of) a large and growing accretionary prism, the Zagros Fold-and-Thrust Belt. Iran's crustal evolution resulted in both significant economic resources and earthquake hazards. Iran is a natural laboratory for studying how convergent plate margins form, evolve, and behave during the early stages of continental collision. Iran formed in the past 600 million years, originating on the northern flank of Gondwana, rifting away, and accreting to SW Eurasia. Iran is actively deforming as a result of collision with the Arabian plate, but earthquakes do not outline the position of the subducting slab. The Cenozoic evolution of Iran preserves the main elements of a convergent plate margin, including foredeep (trench), accretionary prism, and magmatic arc. [ABSTRACT FROM AUTHOR]

My aim in this paper is to consider whether, by thinking of our ethical relation to one another in terms of vulnerability, we can better resolve the problem of overdemandingness – namely, that certain moral views and theories seem to require more of us than is reasonably acceptable. I will suggest that there is a way in which focusing on vulnerability, rather than merely needs or wants, can help address the issue of overdemandingness, largely because of the relational nature of vulnerability, and how this connects to our power over others. In arguing this case, I will draw on the work of the Danish philosopher and theologian K. E. Løgstrup. I explore how Løgstrup shows how this might work in relation to a central form of vulnerability which he emphasises, namely trust. I then consider an objection, namely that trust is a rather special case of vulnerability, which is less open to the problem of overdemandingness only because it has particular features which do not apply to vulnerability more generally. I then respond to this objection by considering if lessons learnt from the case of trust could still nonetheless be extended more widely to other forms of vulnerability. Doing so, I will suggest, might show how thinking in terms of vulnerability as Løgstrup conceives it can help us with the problem of overdemandingness [ABSTRACT FROM AUTHOR]

This paper considers how both Levinas and Løgstrup seek to explain how love of the neighbour is possible. It focuses on a criticism of Levinas made by Merold Westphal, which follows Kierkegaard in arguing on Lutheran grounds that such love first requires a relation to God as a "middle term," but that Levinas cannot appeal to this relation to account for neighbour love, as for him the God relation itself arises through love of the neighbour. In response, the paper explores how Løgstrup, while working in a Lutheran tradition, like Levinas also sees neighbour love as arising without any prior God relation, showing how the accounts that each offer of how this is possible serve to complement each other. [ABSTRACT FROM AUTHOR]

We studied nine samples of igneous rocks from the inner wall of the Mariana Trench above the Challenger Deep from 4150 to 6100 m depth recovered by manned submersible and ROV. Samples from two regions that bracket the Moho were studied: (i) 7 samples from a N‐S transect a few km to the west of the Shinkai Seep Field; and (ii) 2 samples from the Shinkai Seep Field. Transect samples include olivine‐2 pyroxene hornblendites, amphibole basalts, basaltic andesite, and hornblende andesite. We analyzed three transect samples for 40Ar/39Ar ages; two yielded good plateau ages of 46.5 ±0.5 Ma (hornblendite) and 46.60 ±0.15 Ma (hornblende andesite). These results combined with previously published results, indicate that this crust formed during an intense 46–47 Ma magmatic episode that occurred 5–6 my after subduction initiation. Hornblendites and hornblende basalts formed from primitive magmas, as shown by high MgO (11–21 wt%), Ni (222–885 ppm) and Cr (412–1145 ppm) contents. Electron microprobe analyses indicate that hornblende is Na‐rich (up to 3.0 wt% Na2O) and that many samples have an atypically large range in plagioclase composition (i.e. individual samples have An < 10 to An 90 plagioclase). Two subgroups can be identified: a mostly deeper depleted suite and a mostly shallower enriched suite. These results indicate that (i) the crust–mantle boundary in this region is transitional, occurring over a ~ 1.5 km interval, with interlayered peridotite and hornblendites between 5800 and 4300 m; and (b) extension to form the Challenger Deep forearc segment occurred by combined stretching of old crust and injection of young basaltic magmas. In contrast to the mostly fresh nature of transect samples, the two samples from the Shinaki Seep Field are intensely altered peridotite and basalt. [ABSTRACT FROM AUTHOR]

Jurassic igneous bodies of the Sanandaj–Sirjan zone (SaSZ) in SW Iran are generally considered as a magmatic arc but critical evaluation of modern geochronology, geochemistry and radiogenic isotopes challenges this conclusion. There is no evidence for sustained igneous activity along the ~1,200 km long SaSZ, as expected for a convergent plate margin; instead activity was brief at most sites and propagated NW at ~20 mm/a. Jurassic igneous rocks define a bimodal suite of gabbro‐diorite and granite. Chemical and isotopic compositions of mafic rocks indicate subcontinental lithospheric mantle sources that mostly lacked subduction‐related modifications. The arc‐like features of S‐type granites reflect massive involvement of Cadomian crust and younger sediments to generate felsic melts in response to mafic intrusions. We conclude that Jurassic SaSZ igneous activity occurred in a continental rift, not an arc. SaSZ igneous rocks do not indicate that subduction along the SW margin of Eurasia began in Jurassic time. [ABSTRACT FROM AUTHOR]

The existing paradigm for the major ca. 56-48 Ma subduction zone reorganization in the Pacific Northwest of North America is that: (1) the Siletzia large igneous province erupted offshore to the west of North America, forming an oceanic plateau; (2) Siletzia then collided with North America, clogging the Pacific Northwest segment of the Cordilleran subduction zone; and (3) the oceanic lithosphere west of Siletzia then ruptured to initiate the new Cascadia subduction zone. Oceanic lithosphere is strong and difficult to rupture, so this would represent a rare example of such a rupture initiating a new subduction zone. This paper explores an alternative hypothesis for the reorganization, a plume-induced subduction initiation (PISI) mechanism, which has previously been applied to the initiation of Caribbean plate subduction zones in the Cretaceous. In this PISI hypothesis, a newly formed, ~1200-km-diameter Yellowstone mantle plume head rose at ca. 55 Ma beneath western North America, generating Siletzia in situ on the North American margin, as well as generating the ~1700-km-long Challis-Kamloops volcanic belt ~600 km to the east of Siletzia. This destroyed the existing Cordilleran subduction zone and allowed the new Cascadia subduction zone to form by collapse of thermally weakened oceanic lithosphere over the hot western margin of the plume head. This PISI hypothesis provides an integrated framework for understanding Siletzia, the Challis-Kamloops belt, Eocene core complexes from Idaho (U.S.) to British Columbia (Canada), underplated mafic rocks beneath Oregon and Washington (U.S.), post-17 Ma manifestations of the Yellowstone plume, and geophysical characteristics of the lithosphere beneath the Pacific Northwest. [ABSTRACT FROM AUTHOR]

Trace element (TE) ratios of convergent-margin magmas have been found to vary systematically with arc crustal thicknesses. Here we use statistical smoothing techniques along with Sr/Y and La/Yb trace element Moho depth proxies to determine crustal thickness along the volcanic front for three arc segments: the Central Volcanic Zone of the Andes arc, the Central America arc at Nicaragua and Costa Rica, and segments of the Alaska-Aleutian Islands arc (northwesternmost USA). The results are comparable to those from seismic surveys. TE depth proxies give ~70 km crust thickness beneath the Central Volcanic Zone's Altiplano region and show thinner crust (60 km for La/Yb, 43 km for Sr/Y) as the volcanic line crosses into the Puna region. In Central America, the proxy analyses show crustal thickness changes between the Chorotega block and the Nicaragua depression, with both proxies agreeing for Nicaragua (~27 km) but with La/Yb giving considerable thicker (~45 km) crust than Sr/Y (~30 km) for Chorotega. For these two arc segments, the La/Yb proxy approximated the seismically inferred Moho depth to within 10 km for the entire profile, but the Sr/Y proxy-estimated crustal thicknesses diverge from those of the La/Yb proxy and seismic methods in the thin-crust regions. For the Alaska-Aleutian arc, both TE proxies indicate that crust varies from thick (~35 km) for the western Aleutian segment (175°E to 175°W), to thin (~22 km) for the transitional segment (175°W to 158°W), to thick (35+ km) for the eastern Alaska Peninsula (158°W to 150°W). Geophysical estimates favor a crustal thickness of 30-40 km for the same region. We propose that statistically treated geochemistry-based proxies can provide useful estimates of crustal thickness when estimates from Sr/Y and La/Yb agree. We investigated the disagreement in the Alaska-Aleutian case in more detail. Alaska-Aleutian crustal thickness was found to correlate with calc-alkaline (CA) versus tholeiitic (TH) segments of the arc, as represented by along-arc smoothing of the volcanoes' CA-TH indices. The thin crust of the transitional segment trends TH while the thicker crust of the flanking segments trend CA. We find that crustal thickness also plays a role in inferred magma flux (here approximated by volcano volume), with greater flux associated with thinner crust. Thin crust beneath the Alaska-Aleutian transitional segment may reflect continuing loss of cumulates from the lower crust and/or lithospheric mantle into the asthenosphere, leading to enhanced melting beneath this region. [ABSTRACT FROM AUTHOR]

A review of the article “Deep Seismic Structure Across the Southernmost MarianaTrench: Implications for Arc Rifting and Plate Hydration" by Wan et al., which appeared in the periodical “Journal of Geophysical Research: Solid Earth" is presented.

Background: Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease that has been associated with a history of repetitive head impacts. The neuropathological diagnosis is based on a specific pattern of tau deposition with minimal amyloid-beta deposition that differs from other disorders, including Alzheimer's disease. The feasibility of detecting tau and amyloid deposition in the brains of living persons at risk for CTE has not been well studied.Methods: We used flortaucipir positron-emission tomography (PET) and florbetapir PET to measure deposition of tau and amyloid-beta, respectively, in the brains of former National Football League (NFL) players with cognitive and neuropsychiatric symptoms and in asymptomatic men with no history of traumatic brain injury. Automated image-analysis algorithms were used to compare the regional tau standardized uptake value ratio (SUVR, the ratio of radioactivity in a cerebral region to that in the cerebellum as a reference) between the two groups and to explore the associations of SUVR with symptom severity and with years of football play in the former-player group.Results: A total of 26 former players and 31 controls were included in the analysis. The mean flortaucipir SUVR was higher among former players than among controls in three regions of the brain: bilateral superior frontal (1.09 vs. 0.98; adjusted mean difference, 0.13; 95% confidence interval [CI], 0.06 to 0.20; P<0.001), bilateral medial temporal (1.23 vs. 1.12; adjusted mean difference, 0.13; 95% CI, 0.05 to 0.21; P<0.001), and left parietal (1.12 vs. 1.01; adjusted mean difference, 0.12; 95% CI, 0.05 to 0.20; P = 0.002). In exploratory analyses, the correlation coefficients in these three regions between the SUVRs and years of play were 0.58 (95% CI, 0.25 to 0.79), 0.45 (95% CI, 0.07 to 0.71), and 0.50 (95% CI, 0.14 to 0.74), respectively. There was no association between tau deposition and scores on cognitive and neuropsychiatric tests. Only one former player had levels of amyloid-beta deposition similar to those in persons with Alzheimer's disease.Conclusions: A group of living former NFL players with cognitive and neuropsychiatric symptoms had higher tau levels measured by PET than controls in brain regions that are affected by CTE and did not have elevated amyloid-beta levels. Further studies are needed to determine whether elevated CTE-associated tau can be detected in individual persons. (Funded by Avid Radiopharmaceuticals and others.). [ABSTRACT FROM AUTHOR]

Dieser Beitrag bietet eine umfassende Diskussion des Textes "Humanismus und Christentum" (1950) des dänischen Philosophen und Theologen Knud E. Løgstrup. Er verortet den Text in seinem geistesgeschichtlichen Kontext und analysiert seine wichtigsten Argumente wie auch seine zentrale These, der zufolge Humanismus und Christentum einen entscheidenden Grundsatz teilen, insofern beide die Ethik als "stumm" oder "unausgesprochen" verstehen. Darüber hinaus wird dargelegt, wie Løgstrups Text zentrale Überlegungen in dessen späteren Publikationen, besonders in dem Hauptwerk Die ethische Forderung (1956), vorwegnimmt. [ABSTRACT FROM AUTHOR]

To understand how plate tectonics became Earth's dominant mode of convection, we need to address three related problems. (i) What was Earth's tectonic regime before the present episode of plate tectonics began? (ii) Given the preceding tectonic regime, how did plate tectonics become established? (iii) When did the present episode of plate tectonics begin? The tripartite nature of the problem complicates solving it, but, when we have all three answers, the requisite consilience will provide greater confidence than if we only focus on the long-standing question of when did plate tectonics begin? Earth probably experienced episodes of magma ocean, heat-pipe, and increasingly sluggish single lid magmatotectonism. In this effort we should consider all possible scenarios and lines of evidence. As we address these questions, we should acknowledge there were probably multiple episodes of plate tectonic and non-plate tectonic convective styles on Earth. Non-plate tectonic styles were probably dominated by 'single lid tectonics' and this evolved as Earth cooled and its lithosphere thickened. Evidence from the rock record indicates that the modern episode of plate tectonics began in Neoproterozoic time. A Neoproterozoic transition from single lid to plate tectonics also explains kimberlite ages, the Neoproterozoic climate crisis and the Neoproterozoic acceleration of evolution. [ABSTRACT FROM AUTHOR]

Abstract How new subduction zones form is an emerging field of scientific research with important implications for our understanding of lithospheric strength, the driving force of plate tectonics, and Earth's tectonic history. We are making good progress towards understanding how new subduction zones form by combining field studies to identify candidates and reconstruct their timing and magmatic evolution and undertaking numerical modeling (informed by rheological constraints) to test hypotheses. Here, we review the state of the art by combining and comparing results coming from natural observations and numerical models of SI. Two modes of subduction initiation (SI) can be identified in both nature and models, spontaneous and induced. Induced SI occurs when pre-existing plate convergence causes a new subduction zone to form whereas spontaneous SI occurs without pre-existing plate motion when large lateral density contrasts occur across profound lithospheric weaknesses of various origin. We have good natural examples of 3 modes of subduction initiation, one type by induced nucleation of a subduction zone (polarity reversal) and two types of spontaneous nucleation of a subduction zone (transform collapse and plumehead margin collapse). In contrast, two proposed types of subduction initiation are not well supported by natural observations: (induced) transference and (spontaneous) passive margin collapse. Further work is therefore needed to expand on and understand the implications of these observations. Our future advancing understanding of SI will come from better geologic insights, laboratory experiments, and numerical modeling, and with improving communications between these communities. Graphical abstract Image 1 Highlights • Progress in our understanding of how new subduction zones form is reviewed. • 3 ways that new subduction zones formed are presented: polarity reversal, transform collapse, and plume margin collapse. • Future advances in both 2D and 3D numerical modeling expected [ABSTRACT FROM AUTHOR]

A 24-year-old man presented to a university health center in January with a persistent headache that began abruptly 6 days earlier. He noted nonpulsating discomfort in the right retro-orbital area that was not relieved by ibuprofen (400 mg four times daily). He reported no prodromal symptoms, sensitivity to light or sound, neurologic symptoms, nausea, or vomiting and had no history of headaches. A day before presentation, he noted subjective fevers. The patient was evaluated, and amoxicillin was prescribed for presumed acute rhinosinusitis. [ABSTRACT FROM AUTHOR]

Idiopathic multicentric Castleman disease (iMCD) is a rare hematologic illness of systemic inflammation and organ dysfunction, with unknown etiology. Although therapies targeting IL-6 have been proven effective, a subset of patients with iMCD are resistant to this approach. In this issue of the JCI, Fajgenbaum et al. performed an in-depth analysis of serum inflammatory markers in three iMCD patients refractory to IL-6 blockade, and identified activation of the mTOR pathway associated with symptom flares. Treatment with sirolimus, an mTOR inhibitor, induced remission in all three patients. This study models a precision medicine approach to discovering therapies for rare diseases. [ABSTRACT FROM AUTHOR]

When Earth's tectonic style transitioned from stagnant lid (single plate) to the modern episode of plate tectonics is important but unresolved, and all lines of evidence should be considered, including the climate record. The transition should have disturbed the oceans and atmosphere by redistributing continents, increasing explosive arc volcanism, stimulating mantle plumes and disrupting climate equilibrium established by the previous balance of silicate-weathering greenhouse gas feedbacks. Formation of subduction zones would redistribute mass sufficiently to cause true polar wander if the subducted slabs were added in the upper mantle at intermediate to high latitudes. The Neoproterozoic Snowball Earth climate crisis may reflect this transition. The transition to plate tectonics is compatible with nearly all proposed geodynamic and oceanographic triggers for Neoproterozoic Snowball Earth events, and could also have contributed to biological triggers. Only extraterrestrial triggers cannot be reconciled with the hypothesis that the Neoproterozoic climate crisis was caused by a prolonged (200-250 m.y.) transition to plate tectonics. [ABSTRACT FROM AUTHOR]

China covers approximately 10 million km 2 and its crust has a complicated evolution of amalgamation, igneous activity, and sedimentation. Many studies address various aspects of China's crust, but few provide a simple geological and geophysical overview that is accessible to students and non-specialists; Filling this void is the objective of this review. China is characterized by thick (40–75 km) crust in the west due to Cenozoic collision with India and thin (30–40 km thick) crust in the east due to E–W Mesozoic-Cenozoic backarc extension. In contrast, overall crustal fabric trends E–W, defined by ophiolite belts and ultra-high pressure metamorphic rocks. This crustal fabric indicates that China has grown like a sandwich, with crust progressively added through Phanerozoic time by closing various E–W oriented Tethys oceans and seaways. In map view, China consists of five E–W trending tiers. Tier 1 is defined by the Central Asian Orogenic Belt (CAOB) along the northern margin of China, which consists of the Xing'an-Mongolia orogenic belt in the NE and the Tianshan Orogen in the NW. The CAOB formed during ~1000 Ma to ~250 Ma and is an accretionary orogen of mostly Paleozoic age that formed through closure of the Paleo-Asian Ocean and collision between the Siberian Craton and Archean-Paleoproterozoic crust to the south, which constitutes Tier 2. The CAOB has a strong aeromagnetic signature. Sediments from the Amur River show detrital U-Pb zircon age peaks at 2.8–2.3 Ga, 1.8 Ga, 450–250 Ma, and 200–100 Ma, which is expected for erosion of the Xing'an-Mongolia belt. Tier 1 igneous rocks are mainly Paleozoic except in the NE (Xing'an-Mongolia orogenic belt) and reflect subduction of the Paleo-Asian Ocean and associated accretion events, whereas Paleozoic CAOB crust in the east is overprinted by Jurassic and Cretaceous igneous rocks related to subduction of ancient Pacific basin oceanic lithosphere. Tier 2 includes the North China Craton (NCC) to the east and Tarim Craton to the west. The NCC contains the oldest rocks in China and is dominated by Archean and Paleoproterozoic ages. The extent of Archean rocks in the NCC may have been overestimated, as suggested by detrital zircons from the Yellow River, which flows across the craton, showing age peaks at 2.5–2.2 Ga, ~1.9 Ga, 500–400 Ma, and 300–200 Ma. The Tarim Craton is dominated by Palaeoproterozoic- Mesoproterozoic metamorphic strata along with a significant proportion of Neoproterozoic (~0.8 Ga) rocks. U-Pb ages for detrital zircons from Tarim River sediments reflect this basement geology, with strong peaks of Early and Late Paleozoic age, less abundant Neoproterozoic ages, and scattered ages back to the Archean. The NCC also was affected by abundant Mesozoic igneous activity with voluminous Early Cretaceous rocks that are associated with lithospheric thinning and decratonization. Tier 3 – also known as the Central China Orogen - is composed of the Sulu-Dabie-Qinling-Kunlun Orogen and records closing of an arm of Prototethys during the Ordovician to Silurian and Paleotethys during the Triassic. Tier 3 contains one of Earth's three giant ultra-high pressure (UHP) terranes with well-documented peak metamorphism of 650–850 °C and 4 GPa, indicating that some of these rocks were deeply subducted and then exhumed from depths of over 120 km in Triassic time. Tier 3 magmatism occurred in two episodes, early-middle Paleozoic and Triassic. Tier 4 contains blocks rifted from Gondwana, which include the Songpan-Ganzi, Qiangtang, and Lhasa terranes of Tibet in the west and the South China Block in the east. These terranes are marked by broad magnetic anomalies with a NE-SW trend along the Pacific margin, and a broad N–S trending anomaly between Tibet and South China. The South China Block is made up of Proterozoic and minor Archean crust of the Yangtze and Cathaysia blocks, which collided at 1.0–0.8 Ga to form the Jiangnan Orogen and the South China Block. Age spectra for detrital zircons from the Yangtze and Pearl Rivers shows major peaks at ~1.8 Ga, 900–800 Ma, ~400 Ma, and 300–150 Ma, which is consistent with the age of South China Block crust. Early-Middle Paleozoic igneous rocks are also found in South China. Mesozoic igneous rocks are widespread in both South China and Tibet and are related to subduction of the Paleo-Pacific and Tethyan oceanic plates, respectively. The accretion of Tibetan terranes to southern Eurasia occurred in the Mesozoic before collision with India at ~55 Ma. Tier 5 is represented by the island of Taiwan on the SE margin of China and marks where China crust continues to grow. Taiwan lies on a complex convergent boundary between the South China Block to the NW, the Philippine Sea Plate to the SE, and the Sunda Plate to the SW. [ABSTRACT FROM AUTHOR]

Thalamic atrophy has been associated with exposure to repetitive head impacts (RHI) in professional fighters. The aim of this study is to investigate whether or not age at first exposure (AFE) to RHI is associated with thalamic volume in symptomatic former National Football League (NFL) players at risk for chronic traumatic encephalopathy (CTE). Eighty-six symptomatic former NFL players (mean age = 54.9 ± 7.9 years) were included. T1-weighted data were acquired on a 3T magnetic resonance imager, and thalamic volumes were derived using FreeSurfer. Mood and behavior, psychomotor speed, and visual and verbal memory were assessed. The association between thalamic volume and AFE to playing football and to number of years playing was calculated. Decreased thalamic volume was associated with more years of play (left: p = 0.03; right: p = 0.03). Younger AFE was associated with decreased right thalamic volume ( p = 0.014). This association remained significant after adjusting for total years of play. Decreased left thalamic volume was associated with worse visual memory ( p = 0.014), whereas increased right thalamic volume was associated with fewer mood and behavior symptoms ( p = 0.003). In our sample of symptomatic former NFL players at risk for CTE, total years of play and AFE were associated with decreased thalamic volume. The effect of AFE on right thalamic volume was almost twice as strong as the effect of total years of play. Our findings confirm previous reports of an association between thalamic volume and exposure to RHI. They suggest further that younger AFE may result in smaller thalamic volume later in life. [ABSTRACT FROM AUTHOR]

Abstract: Extension within the southern Mariana margin occurs both normal to and parallel to the trench. Trench‐normal extension takes place along focused and broad backarc spreading axes forming crust that is passively accreted to the rigid Philippine Sea plate flank to the northwest. To the southeast, trench‐parallel extension has split apart the Eocene‐Miocene forearc terrain accreting new crust diffusely over a 150–200 km wide zone forming a pervasive volcano‐tectonic fabric oriented at high angles to the trench and the backarc spreading center. Earthquake seismicity indicates active extension over this forearc region and basement samples date young although waning volcanic activity. Such diffuse formation of new oceanic crust and lithosphere is unusual; in most oceanic settings extension rapidly focuses to narrow plate boundary zones—a defining feature of plate tectonics. Diffuse crustal accretion has been inferred to occur during subduction zone infancy, however. We hypothesize that in a near‐trench extensional setting, the continual addition of water from the subducting slab creates a weak overriding hydrous lithosphere that deforms broadly. This process counteracts mantle dehydration and strengthening proposed to occur at mid‐ocean ridges that may help to focus deformation and melt delivery to narrow plate boundary zones. The observations from the southern Mariana margin suggest that where lithosphere is weakened by high water content narrow seafloor spreading centers cannot form. These conditions likely prevail during subduction zone infancy, explaining the diffuse contemporaneous volcanism inferred in this setting. [ABSTRACT FROM AUTHOR]

Why the Challenger Deep, the deepest point on Earth’s solid surface, is so deep is unclear, but part of the reason must be the age and density of the downgoing plate. Northwest Pacific oceanic crust subducting in the Izu-Bonin-Mariana Trench is Cretaceous and Jurassic, but the age and nature of Pacific oceanic crust subducting in the southernmost Mariana Trench remains unknown. Here we present the first study of seafloor basalts recovered by the full-ocean-depth crewed submersible Fendouzhe from the deepest seafloor around the Challenger Deep, from both the overriding and downgoing plates. 40Ar/39Ar ages indicate that downgoing basalts are Early Cretaceous (ca. 125 Ma), indicating they are part of the Pacific plate rather than the nearby Oligocene Caroline microplate. Downgoing-plate basalts are slightly enriched in incompatible elements but have similar trace element and Hf isotope compositions to other northwest Pacific mid-ocean ridge basalts (MORBs). They also have slightly enriched Sr-Nd-Pb isotope compositions like those of the Indian mantle domain. These features may have formed with contributions from plume-derived components via plume-ridge interactions. One sample from the overriding plate gives an 40Ar/39Ar age of ca. 55 Ma, about the same age as subduction initiation, to form the Izu-Bonin-Mariana convergent margin. Our results suggest that 50%–90% of the Pb budget of Mariana arc magmas is derived from the subducted MORBs with Indian-type isotope affinity. [ABSTRACT FROM AUTHOR]

An Ediacaran mafic intrusion of south Jordan is a distinctive appinitic igneous rock with a possibly unique texture, characterized by spherical clots up to 40 mm in diameter composed of amphibole cores from which plagioclase euhedra radiate; we call it the Rosetta Gabbro. It is exposed as a small (ca. 750 m 2 ) outcrop in the Neoproterozoic basement of south Jordan. A second outcrop of otherwise similar gabbro is located about 400 m to the north of the Rosetta Gabbro, but it lacks the distinctive texture. The Rosetta Gabbro could represent a magma pipe. It intrudes the Aqaba Complex (~ 600 Ma) granitoids and metasediments of the Janub Metamorphic Complex (633–617 Ma). The gabbro is an Ol- to QZ tholeiite with the following chemical characteristics: SiO 2 = 46.2–47.8 wt.%; Al 2 O 3 = 16.4–17.7 wt.%, TiO 2 = 1.70–2.82 wt.%, Na 2 O = 1.27–2.83 wt.%. K 2 O = 0.82–1.63 wt.%; Mg# 58–63; Σ REE = 70–117 ppm; La/Yb ~ 6 to 8; and Eu/Eu* = 1.05–1.2. The investigated gabbro has the geochemical features of a continental flood tholeiitic basalt emplaced in a within-plate tectonic setting. Two varieties of amphiboles are found: 1) large, 3–5 mm, brown ferri-titanian-tschermakite (K 0.09 Na 0.28 )(Na 0.20 Ca 1.80 )(Mn 0.04 Fe 3 + 1.1 Mg 2.34 Fe 2 + 0.90 Ti 0.29 Al 0.22 )(Al 1.85 Si 6.15 )O 22 (OH) 1.95 of the calcic amphibole group which is riddled with opaques; and 2) acicular yellowish-light green ferrian-magnesiohornblende (K 0.04 Na 0.153 )(Ca 1.755 Na 0.245 ) (Fe 3 + 0.66 Mn 0.01 Fe 2 + 1.01 Mg 3.03 Ti 0.06 Al 0.22 )(Al 1.03 Si 6.97 )O 22 (OH) 1.95 . Scattered flakes of phlogopite also occur. Tabular radiating plagioclase (An 64–79 ) are complexly twinned, with broad lamellae that show no zoning. Laser-ablation ICP-MS analyses of amphibole and plagioclase reveal considerable variation in trace element abundance, in spite of more subtle major element variations except for TiO 2 in amphibole. The REE in the amphibole shows an order of magnitude variation with a concave-downward pattern and a positive Eu anomaly Eu/Eu* = 0.6–2, though far less pronounced compared to the Eu/Eu* = 5–45 of plagioclase. The 3D dandelion-like texture of the rosettas is broadly similar to “Chrysanthemum Stone”, which is a diagenetic growth in sedimentary rock, but we can find no description of similar textures in igneous rocks. The formation of the rosettas is thought to reflect loss of magmatic water resulting in supersaturation of plagioclase, which grew rapidly around amphibole and may have floated in the magma. This implies magmatic evolution in shallow (10 to 12 km deep) crust where temperatures were nevertheless in the range of ca. 750 to 900 °C. [ABSTRACT FROM AUTHOR]

Today's undergraduate students are accustomed to animations as important to their learning. Complex geologic processes such as subduction are well suited to animation. In spite of this opportunity and need, high-quality animations of fundamental Earth processes are uncommon. We have produced a realistic animation of plate creation and destruction processes for the undergraduate audience. First steps focused on building a storyboard, which is a visual outline of scenes to be animated. Then we organized a team of geoscientists and animators to make the animation. Students generated a rough draft animation, which was polished by a professional animator. We also wrote a narrative that was keyed to the animation, with written "call outs" inserted when terms that may be unfamiliar to undergraduates were spoken. Concepts in the animation are explicitly linked to the scientific literature, with references intended to guide interested viewers to sources to learn more. After the animation and narration were completed, we focused on dissemination and assessment. The animation ("Plate Tectonics Basics 1") was placed on YouTube and the Science Education Resource Center (SERC) portal, and a Japanese version was made. Presentations about the animation were given at the Geological Society of America (GSA) annual meeting and the American Geophysical Union (AGU) Fall meeting. Assessment focused on capturing student understandings before and after watching the animation. Three groups of students were assessed: community college students and lower- and upper-level students at a four-year university. Results of the assessment indicate that students at all levels improved their understanding of subduction zone processes after experiencing the animation, but that upper-level students showed the greatest improvement. More high-quality animations about important plate tectonic processes and additional research into the level of complexity for various student groups are required. [ABSTRACT FROM AUTHOR]

Evidence-based clinical practice guidelines can facilitate proper evaluation and management of concussions in the emergency department (ED), often the initial and primary point of contact for concussion care. There is no universally adopted set of guidelines for concussion management, and extant evidence suggests that there may be variability in concussion care practices and limited application of clinical practice guidelines in the ED. This study surveyed EDs throughout New England to examine current practices of concussion care and utilization of evidence-based clinical practice guidelines in the evaluation and management of concussions. In 2013, a 32-item online survey was e-mailed to 149/168 EDs throughout New England (Connecticut, Rhode Island, Massachusetts, Vermont, New Hampshire, Maine). Respondents included senior administrators asked to report on their EDs use of clinical practice guidelines, neuroimaging decision-making, and discharge instructions for concussion management. Of the 72/78 respondents included, 35% reported absence of clinical practice guidelines, and 57% reported inconsistency in the type of guidelines used. Practitioner preference guided neuroimaging decision-making for 57%. Although 94% provided written discharge instructions, there was inconsistency in the recommended time frame for follow-up care (13% provided no specific time frame), the referral specialist to be seen (25% did not recommend any specialist), and return to activity instructions were inconsistent. There is much variability in concussion care practices and application of evidence-based clinical practice guidelines in the evaluation and management of concussions in New England EDs. Knowledge translational efforts will be critical to improve concussion management in the ED setting. [ABSTRACT FROM AUTHOR]

Background: A multitest approach is optimal for the identification of at-risk driving among older adults. This study examined the predictive validity of a combination of office-based screening tests for on-road driving performance in older adults with and without mild cognitive impairment (MCI)/dementia.Methods: Forty-four normal control, 20 participants with MCI, and 20 participants with dementia completed a battery of office-based assessments. On-road driving evaluation classified participants as not at-risk (n = 65) or at-risk drivers (n = 19).Results: Logistic regression revealed age and 2 tests of visual attention abilities (Useful Field of View [UFOV] Divided Attention and Neuropsychological Assessment Battery [NAB] Driving Scenes) best predicted at-risk drivers ( C statistic = 0.90); no cutoff score had both sensitivity and specificity >80%.Conclusions: Future research on larger and more clinically representative neurological samples will improve understanding of the utility of the UFOV Divided Attention and NAB Driving Scenes in detecting at-risk older adult drivers in the clinic. [ABSTRACT FROM AUTHOR]

This paper considers the prospects for the current revival of interest in Hegel, and the direction it might take. Looking back to Richard J. Bernstein's paper from 1977, on ‘Why Hegel Now?’, it contrasts his optimistic assessment of a rapprochement between Hegel and analytic philosophy with Sebastian Gardner's more pessimistic view, where Gardner argues that Hegel's idealist account of value makes any such rapprochement impossible. The paper explores Hegel's account of value further, arguing for a middle way between these extremes of optimism and pessimism, proposing an Aristotelian reading which is more metaphysical than Bernstein recognizes, but not as at odds with thinking in current analytic philosophy as Gardner suggests, as it finds a counterpart in the work of Philippa Foot, Michael Thompson, Rosalind Hursthouse and others. [ABSTRACT FROM PUBLISHER]

Background: Chronic traumatic encephalopathy (CTE) is a tauopathy associated with prior exposure to repetitive head impacts, such as those incurred through American football and other collision sports. Diagnosis is made through neuropathological examination. Many of the clinical features of CTE are common in the general population, with and without a history of head impact exposure, making clinical diagnosis difficult. As is now common in the diagnosis of other neurodegenerative disorders, such as Alzheimer's disease, there is a need for methods to diagnose CTE during life through objective biomarkers.Objective: The aim of this study was to examine tau-positive exosomes in plasma as a potential CTE biomarker.Methods: Subjects were 78 former National Football League (NFL) players and 16 controls. Extracellular vesicles were isolated from plasma. Fluorescent nanoparticle tracking analysis was used to determine the number of vesicles staining positive for tau.Results: The NFL group had higher exosomal tau than the control group (p <  0.0001). Exosomal tau discriminated between the groups, with 82% sensitivity, 100% specificity, 100% positive predictive value, and 53% negative predictive value. Within the NFL group, higher exosomal tau was associated with worse performance on tests of memory (p = 0.0126) and psychomotor speed (p = 0.0093).Conclusion: These preliminary findings suggest that exosomal tau in plasma may be an accurate, noninvasive CTE biomarker. [ABSTRACT FROM AUTHOR]