1,203 research outputs found

    A Case of Reactive Cervical Lymphadenopathy with Fat Necrosis Impinging on Adjacent Vascular Structures.

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    A tender neck mass in adults can be a diagnostic challenge due to a wide differential diagnosis, which ranges from reactive lymphadenopathy to malignancy. In this report, we describe a case of a young female with an unusually large and tender reactive lymph node with fat necrosis. The diagnostic imaging findings alone mimicked that of scrofula and malignancy, which prompted a complete workup. Additionally, the enlarged lymph node was compressing the internal jugular vein in the setting of oral contraceptive use by the patient, raising concern for Lemierre's syndrome or internal jugular vein thrombosis. This report shows how, in the appropriate clinical context, and especially with the involvement of adjacent respiratory or neurovascular structures, aggressive diagnostic testing can be indicated

    A textural examination of the Yamato 980459 and Los Angeles shergottites using crystal size distribution analysis

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    The basaltic shergottite group is the most plentiful of the Martian meteorite types. Within that compositional category are three distinct textural groups, each suggesting distinct crystallization histories. We present results of a textural study, using crystal size distribution (CSD) analysis, of Yamato (Y) 980459 and Los Angeles, the most primitive and evolved shergottites respectively, and we compare these results to previous CSD work on basaltic shergottites. Y980459 resembles picritic shergottites (e.g. DaG 476), with large zoned olivine set in a groundmass dominated by orthopyroxene. It is unique in having a glassy mesostasis with dendritic olivine and pyroxene, rather than maskelynite. Los Angeles resembles other co-saturated shergottites (e.g. QUE 94201) with a subophitic intergrowth of zoned clinopyroxene and maskelynite. CSD results show Y980459 pyroxenes grew in one stage of steady-state nucleation and growth, cooling at 3-7°C /hr. A CSD of the olivine population suggests slower cooling rates during megacryst formation with an increase during groundmass olivine growth, probably reflecting magma ascent. A CSD plot of Los Angeles pyroxenes shows a smooth downward curvature, also noted in previous analyses of QUE 94201 and EETA79001B. The plot reflects co-crystallization of plagioclase and pyroxene, and supports a single continuous interval of growth

    Misidentifications in the ARC spectra of the rare earths

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    Observations and a model of net calcification declines in Palau's largest coral reef lagoon between 1992 and 2015

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    Author Posting. © American Geophysical Union, 2020. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 125(8), (2020): e2020JC016147, doi:10.1029/2020JC016147.Net ecosystem calcification (NEC) rates of Palau's largest lagoon and barrier reef system between 1992 and 2015 are estimated from sparse total alkalinity (TA) and salinity measurements and a tidal exchange model in which surface lagoon water transported offshore on the ebb tide is replaced by saltier (denser) ocean water that sinks to the bottom after entering the lagoon on the flood tide. Observed lagoon salinities are accurately reproduced by the model with no adjustable parameters. To accurately reproduce observed lagoon TA, NEC for the lagoon‐barrier reef system was 70 mmols m−2 day−1 from 1992 to 1998, 35 mmols m−2 day−1 from 1999 to 2012, and 25 mmols m−2 day−1 from 2013 to 2015. This indicates that Palau's largest lagoon and barrier reef system has not recovered, as of 2015, from the 50% decline in NEC in 1998 caused by the loss of coral cover following a severe bleaching event. The cause of the further decline in NEC in 2012–2013 is unclear. Lagoon residence times vary from 8 days during spring tides to 14 days during neap tides and drive substantial spring‐neap variations in lagoon TA (~25% of the mean salinity‐normalized ocean‐lagoon TA difference). Sparse measurements that do not resolve these spring‐neap variations can exhibit apparent long‐term variations in alkalinity that are not due to changes in NEC.This work was partially supported by NSF award 1220529 to A.L.C., S.J.L., and K.E.F.S and NSF award 1737311 to A.L.C. and the Oceanography Department, Texas A&M University K.E.F.S.2021-01-0

    Quantitative analysis of cell types during growth and morphogenesis in Hydra

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    Tissue maceration was used to determine the absolute number and the distribution of cell types in Hydra. It was shown that the total number of cells per animal as well as the distribution of cells vary depending on temperature, feeding conditions, and state of growth. During head and foot regeneration and during budding the first detectable change in the cell distribution is an increase in the number of nerve cells at the site of morphogenesis. These results and the finding that nerve cells are most concentrated in the head region, diminishing in density down the body column, are discussed in relation to tissue polarity

    Dedicated teams to optimize quality and safety of surgery:A systematic review

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    BACKGROUND: A dedicated operating team is defined as a surgical team consisting of the same group of people working together over time, optimally attuned in both technical and/or communicative aspects. This can be achieved through technical and/or communicative training in a team setting. A dedicated surgical team may contribute to the optimization of healthcare quality and patient safety within the perioperative period. METHOD: A systematic review was conducted to evaluate the effects of a dedicated surgical team on clinical and performance outcomes. MEDLINE and Embase were searched on 23 June 2022. Both randomized controlled trials (RCTs) and non-randomized studies (NRSs) were included. Primary outcomes were mortality, complications and readmissions. Secondary outcomes were costs and performance measures. RESULTS: Fourteen studies were included (RCTs n = 1; NRSs n = 13). Implementation of dedicated operating teams was associated with improvements in mortality, turnover time, teamwork, communication and costs. No significant differences were observed in readmission rates and length of hospital stay. Results regarding duration, glitch counts and complications of surgery were inconclusive. Limitations include study conduct and heterogeneity between studies. CONCLUSIONS: The institution of surgical teams who followed communicative and/or technical training appeared to have beneficial effects on several clinical outcome measures. Dedicated teams provide a feasible way of improving healthcare quality and patient safety. A dose-response effect of team training was reported, but also a relapse rate, suggesting that repetitive training is of major concern to high-quality patient care. Further studies are needed to confirm these findings, due to limited level of evidence in current literature. PROSPERO REGISTRATION NUMBER: CRD42020145288

    Petrology, petrogenesis, and geochronology review of the Cenozoic adakitic rocks of northeast Iran: Implications for evolution of the northern branch of Neo-Tethys

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    Cenozoic adakitic rocks of the northern part of the Central Iran Structural Zone (CISZ) are among the notable geological features of the terrains in northeast Iran, so a comprehensive comparison of several of these adakitic sequences is presented. This lithogeochemical analysis is constrained to examining adakitic magmatism of the three magmatic belts within the CISZ, which from southeast to northeast and from oldest to youngest are as follows: (a) south of Shahrood-Damghan, (b) north-northwest of Sabzevar-Neyshabour, and (c) south of Qouchan and west of Esfarayen. Radiogenic isotope analysis using Rb–Sr and Sm–Nd methods show that the adakitic rocks associated with Qouchan-Esfarayen magmatism have 0.512581 to 0.51288 initial 143Nd/144Nd and 0.703903 to 0.705627 initial 87Sr/86Sr, with ΔNd −0.86 to 4.98. Adakitic rocks in south to southeast Shahrood have 0.512775 to 0.512893 initial 143Nd/144Nd and 0.703746 to 0.705314 initial 87Sr/88Sr, with ΔNd 3.69 to 6.0, and adakites emplaced into the Sabzevar ophiolite have 0.512846 to 0.512911 initial 143Nd/144Nd and 0.70379 to 0.705019 initial 87Sr/86Sr contents with ΔNd of 5.26 to 6.54. Isotopic initial ratios of Nd and Sr support an origin involving partial melting of the subducting oceanic lithosphere of the northern branch of Neo-Tethys and the associated suprasubduction mantle wedge in producing these adakitic rocks

    Probing two-electron multiplets in bilayer graphene quantum dots

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    Understanding how the electron spin is coupled to orbital degrees of freedom, such as a valley degree of freedom in solid-state systems is central to applications in spin-based electronics and quantum computation. Recent developments in the preparation of electrostatically-confined quantum dots in gapped bilayer graphene (BLG) enables to study the low-energy single-electron spectra in BLG quantum dots, which is crucial for potential spin and spin-valley qubit operations. Here, we present the observation of the spin-valley coupling in a bilayer graphene quantum dot in the single-electron regime. By making use of a highly-tunable double quantum dot device we achieve an energy resolution allowing us to resolve the lifting of the fourfold spin and valley degeneracy by a Kane-Mele type spin-orbit coupling of ≈65 Ό\approx 65~\mueV. Also, we find an upper limit of a potentially disorder-induced mixing of the KK and Kâ€ČK' states below 20 Ό20~\mueV.Comment: 5 Pages 5 Figure

    Evidence for Asphericity in the Type IIn Supernova 1998S

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    We present optical spectropolarimetry obtained at the Keck-II 10-m telescope on 1998 March 7 UT along with total flux spectra spanning the first 494 days after discovery (1998 March 2 UT) of the peculiar type IIn supernova (SN) 1998S. The SN is found to exhibit a high degree of linear polarization, implying significant asphericity for its continuum-scattering environment. Prior to removal of the interstellar polarization, the polarization spectrum is characterized by a flat continuum (at p ~ 2%) with distinct changes in polarization associated with both the broad (FWZI >= 20,000 km/s) and narrow (unresolved, FWHM < 300 km/s) line emission seen in the total flux spectrum. When analyzed in terms of a polarized continuum with unpolarized broad-line recombination emission, an intrinsic continuum polarization of p ~ 3% results (the highest yet found for a SN), suggesting a global asphericity of >= 45% from the oblate, electron-scattering dominated models of Hoflich (1991). The smooth, blue continuum evident at early times is shown to be inconsistent with a reddened, single-temperature blackbody, instead having a color temperature that increases with decreasing wavelength. Broad emission-line profiles with distinct blue and red peaks are seen in the total flux spectra at later times, perhaps suggesting a disk-like or ring-like morphology for the dense (n_e ~ 10^7 cm^{-3}) circumstellar medium. Implications of the circumstellar scattering environment for the spectropolarimetry are discussed, as are the effects of uncertain removal of interstellar polarization.Comment: 25 pages + 2 tables + 14 figures, Submitted to The Astrophysical Journa

    Geochemical and Nd-Sr Isotopic Compositions of Hypabyssal Adakites in the Torud-Ahmad Abad Magmatic Belt, Northern Central Iran Zone: Analysis of Petrogenesis and Geodynamic Implications

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    Eocene intermediate to felsic subvolcanic rocks of the Torud-Ahmad Abad magmatic belt (TAMB), in the northern part of the Central Iran zone, are exposed between the Torud and Ahmad Abad regions in South-Southeast Shahrood. These igneous rocks include hypabyssal dacite, trachyte, andesite, trachy-andesite, and basaltic andesite; they are mainly composed of phenocrysts and microcrystalline groundmass of pyroxene, amphibole, and plagioclase, with minor biotite and titanomagnetite; they form domal structures (plugs and stocks), dikes, and sills that intruded into Neoproterozoic to cogenetic Eocene volcano-sedimentary sequences. Based on isotopic analysis of these intermediate to acidic rocks, initial ratios of 143Nd/144Nd range from 0.512 775 to 0.512 893 and initial ratios of 87Sr/86Sr range from 0.703 746 to 0.705 314, with quite positive ΔNd(i) values of +3.69 to +6.00. They are enriched in light rare earth elements and large ion lithophile elements and depleted in heavy rare earth elements and high-field strength elements, the SiO2 content is (52–62) wt.%, and Na2O content &gt;3 wt.%, Al2O3 content &gt;16 wt.%, Yb &lt;1.8 ppm, and Y &lt;18 ppm. These geological, geochemical, and Sr and Nd isotopic data are consistent with adakitic signatures originating by partial melting of the subducted Neo-Tethys oceanic slab (Sabzevar branch) and lithospheric suprasubduction zone mantle. The mantle signatures typifying the rapidly emplaced adakitic rocks (slab (high-silica adakite) and suprasubduction zone (low-silica adakite) melts) together with their locally voluminous extent are evidences that support a locally extensional geodynamic setting; and the evidence is consistent with an evolution to local transpression in the Late Eocene in this convergent margin arc environment to rifting (basalts to adakites) towards submarine conditions in the Neogene
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