A hydrogen-like atom consisting of a positive muon and an electron is known as muonium. It is a near-ideal two-body system for a precision test of bound-state theory and fundamental symmetries. The ...MuSEUM collaboration performed a new precision measurement of the muonium ground-state hyperfine structure at J-PARC using a high-intensity pulsed muon beam and a high-rate capable positron counter. The resonance of hyperfine transition was successfully observed at a near-zero magnetic field, and the muonium hyperfine structure interval of νHFS=4.463302(4)GHz was obtained with a relative precision of 0.9 ppm. The result was consistent with the previous ones obtained at Los Alamos National Laboratory and the current theoretical calculation. We present a demonstration of the microwave spectroscopy of muonium for future experiments to achieve the highest precision.
Abstract
Fecal pellets (FPs) are generated by various species and have gained attention as contributors to the biological carbon pump. Metazoans and protozoans are known as FP and ...minipellet‐producers, respectively. Herein, we discovered fecal pellet‐like dinoflagellates (FLDs) in the seasonal sea ice zone in the Southern Ocean. The size and form of these FLDs were similar to those of zooplankton oval FPs. However, due to their appearance, they have been misclassified as FPs rather than dinoflagellates, leading to potential oversight of their role in the carbon cycle. Thus, we aimed to identify FLD cells at the species level and examine the impact of FLDs on flux estimation of particulate organic carbon (POC). Our findings are as follows: first, FLD cells were identified as
Gyrodinium rubrum
and
Gyrodinium heterogrammum
through 18S rRNA gene sequencing. Second, FLDs can potentially excrete larger FPs than minipellets. Third, the sinking rate of FLDs is higher than that of other protozoa and dinoflagellate cysts. Finally, a maximum of 12 mgC m
−2
day
−1
of the POC flux can be attributed to FLDs (representing 32% of POC flux). These results suggest that FLDs are important drivers not only for the microbial loop but also for the biological carbon pump. In future projections of carbon sequestration, the contribution of metazoans to carbon export must be considered, but not that of FLDs. Their unknown physiological and ecological characteristics, especially including the responses to climate changes, must be urgently investigated for future projections of carbon sequestration in the Southern Ocean.
Plain Language Summary
Zooplankton feed on phytoplankton cells and excrete fecal pellets (FPs). FPs have gained attention as carbon carriers from the surface to the deep ocean because of their high carbon contents and sinking rate. Previous studies have sampled FPs using sediment traps and estimated carbon fluxes through microscopic observations to better understand the ocean carbon cycle. Here, we report the discovery of a dinoflagellate that closely resembles FP and was captured using a drifting sediment trap. This dinoflagellate has been named “fecal‐pellet‐like dinoflagellate (FLD).” It is believed that FLD cells have been misclassified as FPs given their appearance. Our findings indicated that a maximum of 12 mgC m
−2
day
−1
(representing 32% of the particulate organic carbon flux at 50 m depths during the summer productive season) may be attributed to FLD carbon flux. This result suggests that FLD cells serve as potential contributors for carbon export, contrary to the knowledge that heterotrophic dinoflagellates had been known as one of the dominant microbial loop components. Studies on FLDs are essential to understand the Southern Ocean carbon cycle.
Key Points
Fecal pellet‐like dinoflagellates (FLDs) were observed among drifting sediment trap samples in the East Antarctic ice zone
FLD cells were identified as
Gyrodinium rubrum
and
Gyrodinium heterogrammum
FLDs determined as potential players for carbon export that were overlooked because of their appearance
A time-interleaved A-D converter (ADC) system is an effective way to implement a high-sampling-rate ADC with relatively slow circuits. In the system, several channel ADCs operate at interleaved ...sampling times as if they were effectively a single ADC operating at a much higher sampling rate. However, mismatches such as offset, gain mismatches among channel ADCs as well as timing skew of the clocks distributed to them degrade S/N of the ADC system as a whole. This paper analyzes the channel mismatch effects in the time-interleaved ADC system. Previous analysis showed the effect for each mismatch individually, however in this paper we derive explicit formulas for the mismatch effects when all of offset, gain and timing mismatches exist together. We have clarified that the gain and timing mismatch effects interact with each other but the offset mismatch effect is independent from them, and this can be seen clearly in frequency domain. We also discuss the bandwidth mismatch effect. The derived formulas can be used for calibration algorithms to compensate for the channel mismatch effects.
Saline adaptation of granules in mesophilic UASB reactors Kimata-Kino, N.; Ikeda, S.; Kurosawa, N. ...
International biodeterioration & biodegradation,
January 2011, 2011, 2011-01-00, 20110101, Letnik:
65, Številka:
1
Journal Article
Recenzirano
We exposed mesophilic up-flow anaerobic sludge blanket (UASB) reactors to high concentrations of NaCl to elucidate the saline adaptation capacity of their granular sludge. We operated 10 lab-scale ...UASB reactors at 37°C and added NaCl to the influent either abruptly or gradually. With abrupt addition, NaCl concentrations were increased from 0gL−1 to 20, 30, 35, 40, 45, or 50gL−1. With gradual addition, the NaCl concentrations were gradually increased from 0 to 64gL−1 or 0 to 40gL−1. We successfully saline-adapted the granules up to 32g NaCl L−1, while maintaining high reactor performance, suggesting that 32g NaCl L−1 is a practical level for system operation. In the UASB reactors gradually exposed to 32gL−1 NaCl, methane production decreased by only 13%. We also learned that combining abrupt and gradual salinity increases could shorten the adaptation period. Thus we were able to shorten the adaptation period to only 30 days by increasing the salinity abruptly to 20gL−1, followed by gradual adaptation to 30g NaCl L−1.
Aim: In order to evaluate the effects of ammonia on microalgae growth, Chlorella vulgaris was cultivated in ammoniumnitrogen. Methodology: The marine microalgae, Chlorella vulgaris was cultivated in ...algal media containing increasing concentrations of ammonium concentrations at 320,640,960,1600 mg l-1, with free ammonia concentrations of 0.64 to 2.97 mM and pH ranging from 7.78 to 7.82. An addition ammonia treatment was 1600 mg l-1 that had a free ammonia concentration of 13.30 mM, whilea control was NaNO3 at 100 mg l-1. Results: C. vulgaris grew faster when cultured using ammonium nitrogen than nitrate nitrogen. The dry weight of C. vulgaris increased even under extremely high ammonium conditions of 1600 mg-N l-1, which initially contained 2.97 mM free ammonia and reached around 4 g-ds l-1. Algal growth was inhibited in the beginning of the experiment at the highest initial free ammonia concentration of 13.30 mM. However, the cell density increased 2 days later when free ammonia concentration decreased to 3.7 mM due to decrease in pH from 8.48 to 7.88, and the maximum area productivity of 21.12 g-ds m-2 d-1 was observed. Interpretation: These results showed that C. vulgaris could maintain high productivity even in high free ammonia concentrations of 3.7 mM. Because of the high tolerance for free ammonia compared with other microalgae, C. vulgaris can be used for the aquaculture industry by removing ammonia from wastewater, and thus improving thewater quality.
An exercise to compare 10 approaches for the calculation of unweighted whole-body absorbed dose rates was conducted for 74 radionuclides and five of the ICRP’s Reference Animals and Plants, or RAPs ...(duck, frog, flatfish egg, rat and elongated earthworm), selected for this exercise to cover a range of body sizes, dimensions and exposure scenarios. Results were analysed using a non-parametric method requiring no specific hypotheses about the statistical distribution of data. The obtained unweighted absorbed dose rates for internal exposure compare well between the different approaches, with 70% of the results falling within a range of variation of ±20%. The variation is greater for external exposure, although 90% of the estimates are within an order of magnitude of one another. There are some discernible patterns where specific models over- or under-predicted. These are explained based on the methodological differences including number of daughter products included in the calculation of dose rate for a parent nuclide; source–target geometry; databases for discrete energy and yield of radionuclides; rounding errors in integration algorithms; and intrinsic differences in calculation methods. For certain radionuclides, these factors combine to generate systematic variations between approaches. Overall, the technique chosen to interpret the data enabled methodological differences in dosimetry calculations to be quantified and compared, allowing the identification of common issues between different approaches and providing greater assurance on the fundamental dose conversion coefficient approaches used in available models for assessing radiological effects to biota.
Polysora rust, caused by
Puccinia polysora
, is one of the most economically important foliar diseases of maize, and the use of resistant genotypes is the most efficient and economically appropriate ...measure to control this disease. In popcorn, damage caused by this disease is equivalent to that found in common maize. However, studies on the identification of sources of resistance in popcorn are much more scarce. This study aimed to evaluate the reaction of popcorn genotypes regarding polysora rust resistance. For this purpose, 37 temperate and tropical popcorn genotypes were evaluated in randomized block experiments with four replicates in two crop seasons, in Campos dos Goytacazes, RJ, Brazil. Disease intensity was estimated by quantifying incidence and severity using a diagrammatic scale, based on the plant and the leaf immediately below the first ear. We found that incidence can efficiently replace severity at low epidemic levels, facilitating field diagnostics. Also, we observed genetic variability for traits related to polysora rust resistance. The landraces PARA 172, ARZM 05083 and the line L80 are recommended to integrate breeding populations for
Puccinia polysora
resistance as they may carry favorable alleles for disease control.
Follistatin (FS), an activin-binding protein, is a monomer derived from two polypeptide core sequences of 315 (FS-315) and
288 (FS-288) amino acids originated from alternatively spliced mRNA. To ...define the structural heterogeneity of native FS,
we purified six molecular forms of FS from porcine ovaries. Protein chemical analysis revealed that the structural differences
among the six isoforms were caused by truncation of the carboxyl-terminal region and/or the presence of carbohydrate chains,
resulting in the formation of FS-315, FS-288, and FS composed of 303 amino acids (FS-303) in various forms of glycosylation
on the two potential Asn-linked glycosylation sites. The majority of FS isolated from porcine ovaries was FS-303, which may
have been derived from FS-315 by proteolytic cleavage of the 12 COOH-terminal amino acids. All six molecular species have
almost the same activin binding activity (Kd = 540-680 pM). By contrast, the COOH-terminal truncated form, FS-288, showed
much higher affinity for the rat granulosa cell surface than FS-303, whereas FS-315 had no affinity. FS-288 bound to heparan
sulfate-Sepharose CL-4B, but FS-315 did not, suggesting that the truncated forms of FS bind to heparan sulfate proteoglycans
on the cell. COS cells transfected with the FS-288 DNA expressed the FS-288 protein, which adhered to the cell surface, but
cells transfected with the FS-315 DNA secreted the expressed protein into the medium, which did not bind to the cell surface.
In rat anterior pituitary culture, FS-288 (ED50 = 2 ng/ml) was more potent in suppressing follicle-stimulating hormone release
than FS-303 (ED50 = 10 ng/ml) and FS-315 (ED50 = 20 ng/ml). These results suggest that cell-associated FS traps activin more
tightly in the matrix, thereby more effectively blocking the activity of activin on heparan sulfate proteoglycans of the cell
surface and that cell-associated FS plays an important role in controlling the various actions of activin in a paracrine or
autocrine manner.
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