Free traveling Rossby wave normal modes (RNMs) are often investigated through large‐scale space‐time spectral analyses, which therefore is subject to observational availability, especially in the ...mesosphere. Ground‐based mesospheric observations were broadly used to identify RNMs mostly according to the periods of RNMs without resolving their horizontal scales. The current study diagnoses zonal wave numbers of RNM‐like oscillations occurring in mesospheric winds observed by two meteor radars at about 79°N. We explore four winters comprising the major stratospheric sudden warming events (SSWs) 2009, 2010, and 2013. Diagnosed are predominant oscillations at the periods of 10 and 16 days lasting mostly for three to five whole cycles. All dominant oscillations are associated with westward zonal wave number m=1, excepting one 16‐day oscillation associated with m=2. We discuss the m=1 oscillations as transient RNMs and the m=2 oscillation as a secondary wave of nonlinear interaction between an RNM and a stationary Rossby wave. All the oscillations occur around onsets of the three SSWs, suggesting associations between RNMs and SSWs. For comparison, we also explore the wind collected by a similar network at 54°N during 2012–2016. Explored is a manifestation of 5‐day wave, namely, an oscillation at 5–7 days with m=1), around the onset of SSW 2013, supporting the associations between RNMs and SSWs.
Plain Language Summary
Most detectable atmospheric Rossby waves are associated with atmospheric intrinsic properties, including the free traveling Rossby wave normal modes and forced resonant stationary Rossby waves. The former is less understood than the latter because they are relatively weak and often distorted by the background atmosphere. In the current work, we customize a compact wave identifying technique to estimate the horizontal wavelength of Rossby wave‐like predominant 10‐ and 16‐day oscillations detected by two arctic radars during stratospheric sudden warming events. Results illustrate that five of the six most oscillations are westward traveling with zonal wave number 1. We explain the oscillations as free transient Rossby wave normal modes.
Key Points
Two radars at polar latitude are combined to diagnose zonal wave number m of Rossby wave‐like oscillations occurring around four SSW onsets
Transient 10‐ and 16‐day oscillations are mostly associated with m=1, and therefore should be Rossby wave normal modes
A 16‐day oscillation is associated with m=2, resulting potentially from nonlinear interactions of the 16‐day wave with a stationary Rossby wave
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Amphibole, while uncommon as a phenocryst in arc lavas, is increasingly recognized as a key constituent in the petrogenesis of arc magmas. Fractional crystallization of water-saturated arc magmas in ...the lower crust can yield substantial volumes of amphibole cumulates that, depending on the pressure of crystallization, may also contain garnet. Fractionation of this higher pressure assemblage has been invoked as a possible mechanism in the production of magmas that contain an adakitic signature. This study examines newly dated Late-Oligocene (25.37 ± 0.13 Ma) hypabyssal amphibole-rich andesites from Cerro Patacon in the Panama Canal region. These andesites contain nodules of amphibole cumulates that are ~4–6 cm in diameter and are almost entirely composed of 5–10-mm amphibole crystals (dominantly ferri-tschermakite). Geochemical variations, optical and chemical zoning of the Cerro Patacon amphiboles are consistent with their evolution in a crystal mush environment that had at least one recharge event prior to entrainment in the host andesite. Amphiboles hosted within the cumulate nodules differ from those hosted in the Cerro Patacon andesite and contain consistently higher values of Ti. We suggest these nodules represent the early stages of fractionation from a water-saturated magma. Cerro Patacon andesites have REE concentrations that plot at the most depleted end of Central American Arc magmas and exhibit a distinctive depletion in the middle REE. These geochemical and petrographic observations strongly support significant amphibole fractionation during formation of the Cerro Patacon andesite, consistent with the petrographic evidence. Fractionation of water-saturated magmas is a mechanism by which adakitic compositions may be produced, and the Cerro Patacon andesites do exhibit adakite-like geochemical characteristics (e.g., elevated Sr/Y; 28–34). However, the relatively elevated concentrations of Y and HREE indicate garnet was not stable in the fractionating assemblage during this early stage of arc development.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The existing distribution of meteor radars located from high- to
low-latitude regions provides a favorable temporal and spatial coverage for
investigating the climatology of the global mesopause ...density. In this
study, we report the climatology of the mesopause relative density estimated
using multiyear observations from nine meteor radars, namely, the Davis
Station (68.6∘ S, 77.9∘ E), Svalbard (78.3∘ N,
16∘ E) and Tromsø (69.6∘ N, 19.2∘ E) meteor
radars located at high latitudes; the Mohe (53.5∘ N,
122.3∘ E), Beijing (40.3∘ N, 116.2∘ E),
Mengcheng (33.4∘ N, 116.6∘ E) and Wuhan (30.5∘ N, 114.6∘ E) meteor radars located in the midlatitudes; and the
Kunming (25.6∘ N, 103.8∘ E) and Darwin (12.3∘ S, 130.8∘ E) meteor radars located at low latitudes. The daily
mean relative density was estimated using ambipolar diffusion coefficients
derived from the meteor radars and temperatures from the Microwave Limb
Sounder (MLS) on board the Aura satellite. The seasonal variations in the
Davis Station meteor radar relative densities in the southern polar
mesopause are mainly dominated by an annual oscillation (AO). The mesopause
relative densities observed by the Svalbard and Tromsø meteor radars at
high latitudes and the Mohe and Beijing meteor radars at high midlatitudes
in the Northern Hemisphere show mainly an AO and a relatively weak
semiannual oscillation (SAO). The mesopause relative densities observed by
the Mengcheng and Wuhan meteor radars at lower midlatitudes and the Kunming
and Darwin meteor radars at low latitudes show mainly an AO. The SAO is
evident in the Northern Hemisphere, especially at high latitudes, and its
largest amplitude, which is detected at the Tromsø meteor radar, is
comparable to the AO amplitudes. These observations indicate that the
mesopause relative densities over the southern and northern high latitudes
exhibit a clear seasonal asymmetry. The maxima of the yearly variations in
the mesopause relative densities display a clear latitudinal variation
across the spring equinox as the latitude decreases; these latitudinal
variation characteristics may be related to latitudinal changes influenced
by gravity wave forcing. In addition to an AO, the mesopause relative
densities over low latitudes also clearly show an intraseasonal variation
with a periodicity of 30–60 d.
Prompt neutrophil arrival is critical for host defense immediately after injury 1–3. Following wounding, a hydrogen peroxide (H2O2) burst generated in injured tissues is the earliest known leukocyte ...chemoattractant 4. Generating this tissue-scale H2O2 gradient uses dual oxidase 4 and neutrophils sense H2O2 by a mechanism involving the LYN Src-family kinase 5, but the molecular mechanisms responsible for H2O2 clearance are unknown 6. Neutrophils carry abundant amounts of myeloperoxidase, an enzyme catalyzing an H2O2-consuming reaction 7, 8. We hypothesized that this neutrophil-delivered myeloperoxidase downregulates the high tissue H2O2 concentrations that follow wounding. This was tested in zebrafish using simultaneous fluorophore-based imaging of H2O2 concentrations and leukocytes 4, 9–11 and a new neutrophil-replete but myeloperoxidase-deficient mutant (durif). Leukocyte-depleted zebrafish had an abnormally sustained wound H2O2 burst, indicating that leukocytes themselves were required for H2O2 downregulation. Myeloperoxidase-deficient zebrafish also had abnormally sustained high wound H2O2 concentrations despite similar numbers of arriving neutrophils. A local H2O2/myeloperoxidase interaction within wound-recruited neutrophils was demonstrated. These data demonstrate that leukocyte-delivered myeloperoxidase cell-autonomously downregulates tissue-generated wound H2O2 gradients in vivo, defining a new requirement for myeloperoxidase during inflammation. Durif provides a new animal model of myeloperoxidase deficiency closely phenocopying the prevalent human disorder 7, 12, 13, offering unique possibilities for investigating its clinical consequences.
► Leukocytes themselves downregulate the H2O2 burst after wounding ► They do so through neutrophil delivery of myeloperoxidase ► At the wound, myeloperoxidase and H2O2 interact directly within neutrophils ► A zebrafish myeloperoxidase-deficient mutant phenocopies the common human disorder
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Upper mesospheric winds observed by the Svalbard specular meteor radar (16.01°E,78.16°N) are analyzed to study the tidal variabilities during the 2009 sudden stratospheric warming (SSW). We report a ...textbook case of nonlinear interactions between planetary waves (PWs) and the SW2 tide (SWm denotes semidiurnal westward propagating tidal mode with zonal wave number m). The Lomb‐Scargle algorithm, bispectrum, wavelet spectra, and Manley‐Rowe relations are combined to explore the frequency match, phase coherence, energy budget, and wave number relations among the interacting waves and their temporal evolution. Our results suggest that (1) 5, 10, 16 day PW normal modes interact with SW2 generating significant sidebands (S2Ss) at frequencies lower and higher than SW2, known as SW1 and SW3 enhancements, respectively; (2) SW2 is the main energy supplier for both SW1 and SW3, hence shrinks in the interactions; (3) whereas the PWs export relatively negligible energy to SW3 but accept energy from SW2 in generating SW1, therefore, the PWs is not subject to the interactions but controlled by external dynamics, which might in turn act as a key in switching on/off the SW1 and SW3 interactions independently; (4) the SW1 enhancement could be explained as a byproduct of the planetary wave amplification by stimulated tidal decay (PASTIDE); (5) PASTIDE contributes energy to the secondary PW in the late SSW stage reported in previous studies; and (6) one SW1 component associated with the 16 day PW is very close to the semidiurnal lunar mode in frequency, which might contaminate the estimation of the lunar tidal amplification in previous studies.
Plain Language Summary
Nonlinear interaction is a prototypical behavior of waves, as fundamental as Doppler shift, interference, and diffraction. Nonlinear interactions between atmospheric planetary scale waves have been reported in numerous studies. In the current work, we apply for the first time Manley‐Rowe relations to determine the energy flow in the atmospheric interactions and roles of the interacting waves. Particularly, we report and analyze a textbook case of nonlinear interactions between planetary waves (PWs) and the migrating solar semidiurnal tide. Our analysis suggests that the secondary waves, well known as zonal wave 1 and wave 3 enhancements, are fed on the energy mainly from the tide. Although the energy flow through PWs is relatively negligible, our investigations suggest that the energy budget of PWs might act as a key in turning on/off the interactions. When PWs accept energy in the interaction, the wave 1 is generated, whereas when PWs export energy, the wave 3 is generated. In the combined case, PWs could accept energy from the tide and meanwhile export energy to wave 3, generating both wave 1 and wave 3. The energy transport from the tide to PWs in generating wave 1 might supply the secondary PW in the late sudden stratospheric warming stage reported in previous studies.
Key Points
A textbook case of nonlinear interactions between planetary waves and SW2 tide results in asynchronous SW1 and SW3
Manley‐Rowe relations explain the energy flow topology and the roles of interacting waves; SW1 is accompanied by secondary PW
SW1 contaminates the estimation of M2 amplification; we suggest tentative scenarios for interpreting the SW1/SW3 asynchrony
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Enhanced nonmigrating tides SW1 (SWx represents semidiurnal westward mode with zonal wave number x) and SW3 during sudden stratospheric warming (SSW) were traditionally attributed to nonlinear ...interactions of quasi‐stationary planetary waves with the migrating tide SW2. Recent studies specified hypothetically that responsible for the interactions is the 16‐day wave, instead of the broadly accepted quasi‐stationary planetary waves. It is suspected that the 16‐day‐wave‐triggered secondary waves, at periods ∼12.4 and ∼11.6 hr, were detected at low‐frequency resolutions and misinterpreted as SW1 and SW3, respectively. While He et al. (2018, https://doi.org/10.1002/2018JD028400) associated the 11.6‐hr oscillation conclusively to the SW3‐like signature during SSW 2013 by diagnosing its wave number, the SW1‐like 12.4hr wave, however, has never been explicitly resolved, given its proximity to the period of an active lunar tide. Here, using the coherency in the mesospheric wind between two longitudinal sectors during SSW 2009, we identify a 12.4‐hr oscillation dominated by wave number 1 and therefore associate it to the SW1‐like signature.
Plain Language Summary
The winter upper atmosphere is populated by global‐scale oscillations among which the most radical one appears nearby the period of 12 hr. The existing studies suggest that the near‐12‐hr oscillation consists of at least six waves, namely, the migrating lunar and solar tides, two nonmigrating tides, and two secondary waves of the nonlinear interactions between the migrating solar tide and traveling planetary waves. The current work, together with a counterpart work (He et al., 2018), disentangles the near‐12‐hr oscillation into high‐frequency‐resolved isolated spectral peaks and investigates the longitudinal variation in the phase of the isolated peaks through jointly studying the mesospheric wind collected by longitudinally separated radars in early 2009 and early 2013. Results suggest that the nonmigrating tides did not enhance in both cases and demonstrate that the occurrence of secondary waves might have been misinterpreted as the nonmigrating tides in studies at low‐frequency resolutions.
Key Points
We report an upper atmospheric pseudo‐SW1, a 12.4‐hr oscillation characterized by westward traveling wave number 1 structure
The nonlinear interaction between the 16‐day wave and the semidiurnal migrating tide SW2 triggers the pseudo‐SW1
The broadly reported SW1‐like enhancements during sudden stratospheric warming events are conceptually not tides
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Zebrafish (Danio rerio) has recently emerged as a powerful experimental model in drug discovery and environmental toxicology. Drug discovery screens performed on zebrafish embryos mirror with a high ...level of accuracy the tests usually performed on mammalian animal models, and fish embryo toxicity assay (FET) is one of the most promising alternative approaches to acute ecotoxicity testing with adult fish. Notwithstanding this, automated in-situ analysis of zebrafish embryos is still deeply in its infancy. This is mostly due to the inherent limitations of conventional techniques and the fact that metazoan organisms are not easily susceptible to laboratory automation. In this work, we describe the development of an innovative miniaturized chip-based device for the in-situ analysis of zebrafish embryos. We present evidence that automatic, hydrodynamic positioning, trapping and long-term immobilization of single embryos inside the microfluidic chips can be combined with time-lapse imaging to provide real-time developmental analysis. Our platform, fabricated using biocompatible polymer molding technology, enables rapid trapping of embryos in low shear stress zones, uniform drug microperfusion and high-resolution imaging without the need of manual embryo handling at various developmental stages. The device provides a highly controllable fluidic microenvironment and post-analysis eleuthero-embryo stage recovery. Throughout the incubation, the position of individual embryos is registered. Importantly, we also for first time show that microfluidic embryo array technology can be effectively used for the analysis of anti-angiogenic compounds using transgenic zebrafish line (fli1a:EGFP). The work provides a new rationale for rapid and automated manipulation and analysis of developing zebrafish embryos at a large scale.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Convolution and matched filtering are often used to detect a known signal in the presence of noise. The probability of detection and probability of missed detection are well known and widely used ...statistics. Oftentimes we are not only interested in the probability of detecting a signal but also accurately estimating when the signal occurred and the error statistics associated with that time measurement. Accurately representing the timing error is important for geolocation schemes, such as Time of Arrival (TOA) and Time Difference of Arrival (TDOA), as well as other applications. The Cramér Rao Lower Bound (CRLB) and other, tighter, bounds have been calculated for the error variance on Time of Arrival estimators. However, achieving these bounds requires an amount of interpolation be performed on the signal of interest that may be greater than computational constraints allow. Furthermore, at low Signal to Noise Ratios (SNRs), the probability distribution for the error is non-Gaussian and depends on the shape of the signal of interest. In this paper we introduce a method of characterizing the localization accuracy of the matched filtering operation when used to detect a discrete signal in Additive White Gaussian Noise (AWGN) without additional interpolation. The actual localization accuracy depends on the shape of the signal that is being detected. We develop a statistical method for analyzing the localization error probability mass function for arbitrary signal shapes at any SNR. Finally, we use our proposed analysis method to calculate the error probability mass functions for a few signals commonly used in detection scenarios. These illustrative results serve as examples of the kinds of statistical results that can be generated using our proposed method. The illustrative results demonstrate our method's unique ability to calculate the non-Gaussian, and signal shape dependent, error distribution at low Signal to Noise Ratios. The error variance calculated using the proposed method is shown to closely track simulation results, deviating from the Cramér Rao Lower Bound at low Signal to Noise Ratios.
Geobacillus species are important contaminants in the dairy industry, and their presence is often considered an indicator of poor plant hygiene with the potential to cause spoilage. They can form ...heat-resistant spores that adhere to surfaces of processing equipment and germinate to form biofilms. Therefore, strategies aimed toward preventing or controlling biofilm formation in the dairy industry are desirable. In this study, we demonstrated that the preferred temperature for biofilm and spore formation among Geobacillus stearothermophilus A1, D1, P3, and ATCC 12980 was 65°C. Increasing the total dissolved milk solid concentration to 20% (wt/vol) caused an apparent delay in the onset of biofilm and spore formation to detectable concentrations among all the strains at 55°C. Compared to the onset time of the biofilm formation of A1 in 10% (wt/vol) reconstituted skim milk, addition of milk protein (whey protein and sodium caseinate) caused an apparent delay in the onset of biofilm formation to detectable concentrations by an average of 10 h at 55°C. This study proposes that temperature and total dissolved solid concentration have a cumulative effect on biofilm and spore formation by G. stearothermophilus A1, D1, P3, and ATCC 12980. In addition, the findings from this study may indicate that preconditioning of stainless steel surfaces with adsorbed milk proteins may delay the onset of biofilm and spore formation by thermophilic bacteria during milk powder manufacture. IMPORTANCE The thermophilic bacillus Geobacillus stearothermophilus is a predominant spoilage bacterium in milk powder manufacturing plants. If its numbers exceed the accepted levels, financial losses may be incurred because of the need to lower the price of the end product. Furthermore, G. stearothermophilus bacilli can form heat-resistant spores which adhere to processing surfaces and can germinate to form biofilms. Previously conducted research had highlighted the variation in the spore and biofilm formation among three specific strains of G. stearothermophilus isolated from a milk powder manufacturing plant in New Zealand. The significance of our research is in demonstrating the effects of two abiotic factors, namely, temperature and total dissolved solid concentration, on biofilm and spore formation by these three dairy isolates, leading to modifications in the thermal processing steps aimed toward controlling biofilm and spore formation by G. stearothermophilus in the dairy industry.
This study places constraints on the source and transport mechanisms of methane found in groundwater within the Barnett Shale footprint in Texas using dissolved noble gases, with particular emphasis ...on 84Kr and 132Xe. Dissolved methane concentrations are positively correlated with crustal 4He, 21Ne, and 40Ar and suggest that noble gases and methane originate from common sedimentary strata, likely the Strawn Group. In contrast to most samples, four water wells with the highest dissolved methane concentrations unequivocally show strong depletion of all atmospheric noble gases (20Ne, 36Ar, 84Kr, 132Xe) with respect to air-saturated water (ASW). This is consistent with predicted noble gas concentrations in a water phase in contact with a gas phase with initial ASW composition at 18 °C-25 °C and it suggests an in situ, highly localized gas source. All of these four water wells tap into the Strawn Group and it is likely that small gas accumulations known to be present in the shallow subsurface were reached. Additionally, lack of correlation of 84Kr/36Ar and 132Xe/36Ar fractionation levels along with 4He/20Ne with distance to the nearest gas production wells does not support the notion that methane present in these groundwaters migrated from nearby production wells either conventional or using hydraulic fracturing techniques.
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IJS, KILJ, NUK, PNG, UL, UM
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