Seasonal changes in the abundance and taxonomic composition of bottom ice protists (i.e. diatoms, flagellates, and dinoflagellates) were assessed in the first-year landfast ice of Franklin Bay ...(Canadian Beaufort Sea) from 24 February to 20 June 2004. On each sampling day, bottom sea-ice protists were collected at sites of high (>10 cm) and low (<10 cm) snow cover. The net observed growth rates of diatoms and nanoflagellates were significantly higher during the pre-bloom (24 February to 25 March) than the bloom (ca. 3 April to 23 May) period under low snow cover but were not different under high snow cover. In contrast, dinoflagellates showed relatively constant net observed growth rate before and during the bloom period under both snow covers. These results indicate that the 3 protist groups responded differently to changes in the light regime during the growth period. The decline of the protist community after the bloom period was related to a combination of factors including nitrogen deficiency and melting processes. Prior to the bloom, flagellated cells, likely heterotrophic, dominated numerically under high snow cover, whereas autotrophic protists, especially solitary diatoms, prevailed under low snow cover. During the bloom period, colonial diatoms such asNitzschia frigida,N. promare,Naviculasp. 6,N. pelagica, andFragilariopsis cylindrusdominated the bottom ice community irrespective of snow depth, although abundances were higher under low snow cover. The arborescent colonialN. frigida, a key species of landfast ice across circumarctic regions, was the most abundant bottom ice algal diatom throughout the entire season. During the post-bloom period, colonial and solitary diatoms declined more rapidly than nanoflagellates, suggesting that nanoflagellates, presumably heterotrophic, were better adapted to melting sea-ice conditions. Our results demonstrated that the availability of nitrate in the surface water limits the accumulation of algal biomass in the bottom horizon of Arctic landfast ice during the vernal growth season.
The attenuation coefficient b is one of the most common ways to describe how strong the carbon flux is attenuated throughout the water column. Therefore, b is an essential input variable in many ...carbon flux and climate models. Marsay et al. (2015, https://doi.org/10.1073/pnas.1415311112) proposed that the median surface water temperature (0–500 m) may be a predictor of b, but our observations from Arctic waters challenge this hypothesis. We found a highly variable attenuation coefficient (b = 0.43–1.84) in cold Arctic waters (<4.1 °C). Accordingly, we suggest that water temperature is not a globally valid predictor of the attenuation coefficient. We advocate instead that the phytoplankton composition and especially the relative abundance of diatoms can be used to parametrize the carbon flux attenuation in local and global carbon flux models.
Plain Language Summary
In the surface ocean, microalgae convert dissolved atmospheric CO2 into organic carbon (OC). As OC sinks in the water column, microbes and zooplankton graze on it. It has been suggested that these organisms reduce the amount of sinking OC stronger in warm waters than in cold waters. We found, however, that the amount of sinking OC is sometimes strongly and sometimes weakly reduced in cold Arctic waters (<4 °C). Therefore, we conclude that temperature seems not to be an important factor determining how strong the amount of sinking OC is reduced with depth. We instead advocate that the phytoplankton community composition is useful to predict how strong the amount of sinking OC is reduced with depth. When fast‐sinking algae form algal aggregates or are repackaged into copepod fecal pellets, their OC spends only a short time in the upper water column where hungry grazers are very abundant. The consumers have then much less time to prey on the OC than when the sinking particles consist of slowly sinking algae. Concluding, we argue that it is very important to include the phytoplankton community composition in computer simulations to correctly predict how much OC is stored in the oceans.
Key Points
Unlike previous assumptions, carbon flux attenuation can both be weak and strong in cold Arctic waters (<4 °C)
Phytoplankton community composition is a more reliable predictor of carbon flux attenuation than temperature alone
Phytoplankton and zooplankton abundance and composition should be included in carbon flux models as these parameters can modify b
The Belle II Silicon Vertex Detector Friedl, M.; Ackermann, K.; Aihara, H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2013, Letnik:
732
Journal Article
Recenzirano
Odprti dostop
The KEKB machine and the Belle experiment in Tsukuba (Japan) are now undergoing an upgrade, leading to an ultimate luminosity of 8×1035cm−2s−1 in order to measure rare decays in the B system with ...high statistics.
The previous vertex detector cannot cope with this 40-fold increase of luminosity and thus needs to be replaced. Belle II will be equipped with a two-layer Pixel Detector surrounding the beam pipe, and four layers of double-sided silicon strip sensors at higher radii than the old detector. The Silicon Vertex Detector (SVD) will have a total sensitive area of 1.13m2 and 223,744 channels—twice as many as its predecessor.
All silicon sensors will be made from 150mm wafers in order to maximize their size and thus to reduce the relative contribution of the support structure. The forward part has slanted sensors of trapezoidal shape to improve the measurement precision and to minimize the amount of material as seen by particles from the vertex. Fast-shaping front-end amplifiers will be used in conjunction with an online hit time reconstruction algorithm in order to reduce the occupancy to the level of a few percent at most. A novel “Origami” chip-on-sensor scheme is used to minimize both the distance between strips and amplifier (thus reducing the electronic noise) as well as the overall material budget.
This report gives an overview on the status of the Belle II SVD and its components, including sensors, front-end detector ladders, mechanics, cooling and the readout electronics.
Activities of N-acetyl-beta-d-glucosaminidase and glutathione peroxidase in bovine colostrum and milk Kankofer, M.,University of Life Sciences, Lublin (Poland). Dept. of Animal Biochemistry and Physiology; Albera, E.,University of Life Sciences, Lublin (Poland). Dept. of Animal Biochemistry and Physiology; Rozanska-Boczula, M.,University of Life Sciences, Lublin (Poland). Dept. of Applied Mathematics
Czech Journal of Animal Science,
(Nov 2010), Letnik:
55, Številka:
11
Journal Article
Recenzirano
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Parturition and post partum period are susceptible for antioxidative/oxidative imbalance as well as inflammatory processes related to either uterus or mammary gland. Fifteen Holstein-Friesian cows ...were used to examine the relationship between the antioxidant enzyme glutathione peroxidase (GSH-Px) and inflammatory enzyme N-acetyl-glucosaminidase (NAGase) in colostrum and milk during 12 days after parturition. Samples from each udder quarter were collected immediately after parturition, after 24 h and 48 h as well as after 6 and 12 days post partum. The activity of GSH-Px was measured spectrophotometrically and NAGase spectrofluorimetrically. NAGase activity generally remained constant during the examined period confirming no inflammation and healthy udder. Moreover, no significant differences in the activity among quarters were detected. The activity of GSH-Px rose significantly in the examined period suggesting the dynamic balance of antioxidative defence. No differences among quarters confirmed that in healthy quarters metabolic processes are on a similar level but positive correlations between the antioxidative and inflammatory enzyme in quarters and with regard to time may suggest a possible relationship during inflammation.
Protist abundance and taxonomic composition were determined in four development stages of newly formed sea ice (new ice, nilas, young ice and thin first-year ice) and in the underlying surface waters ...of the Canadian Beaufort Sea from 30 September to 19 November 2003. Pico- and nanoalgae were counted by flow cytometry whereas photosynthetic and heterotrophic protists ≥
4 µm were identified and counted by inverted microscopy. Protists were always present in sea ice and surface water samples throughout the study period. The most abundant protists in sea ice and surface waters were cells <
4 µm. They were less abundant in sea ice (418–3051
×
10
3 cells L
−
1
) than in surface waters (1393–5373
×
10
3 cells L
−
1
). In contrast, larger protists (≥
4 µm) were more abundant in sea ice (59–821
×
10
3 cells L
−
1
) than in surface waters (22–256
×
10
3 cells L
−
1
). These results suggest a selective incorporation of larger cells into sea ice. The ≥
4 µm protist assemblage was composed of a total number of 73 taxa, including 12 centric diatom species, 7 pennate diatoms, 11 dinoflagellates and 16 flagellates. The taxonomic composition in the early stage of ice formation (i.e., new ice) was very similar to that observed in surface waters and was composed of a mixed population of nanoflagellates (Prasinophyceae and Prymnesiophyceae), diatoms (mainly
Chaetoceros species) and dinoflagellates. In older stages of sea ice (i.e., young ice and thin first-year ice), the taxonomic composition became markedly different from that of the surface waters. These older ice samples contained relatively fewer Prasinophyceae and more unidentified nanoflagellates than the younger ice. Diatom resting spores and dinoflagellate cysts were generally more abundant in sea ice than in surface waters. However, further studies are needed to determine the importance of this winter survival strategy in Arctic sea ice. This study clearly shows the selective incorporation of large cells (≥
4 µm) in newly formed sea ice and the change in the taxonomic composition of protists between sea ice and surface waters as the fall season progresses.
Present trends in bariatric surgery in Poland Walędziak, Maciej; Różańska-Walędziak, Anna M; Kowalewski, Piotr K ...
Videosurgery and Other Miniinvasive Techniques/Wideochirurgia i Inne Techniki Mało Inwazyjne,
01/2019, Letnik:
14, Številka:
1
Journal Article
Recenzirano
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As obesity has become a major health problem in Poland and bariatric procedures are the best way of treatment, an increasing trend has been observed in Polish bariatric surgery for the last decade.
...Our purpose was to provide an updated overview of the bariatric surgical procedures performed in Polish institutions in comparison to the situation in Europe as well as to analyze the trends in Polish bariatric surgery over the last decades.
A questionnaire about the number and type of bariatric procedures performed in 2016 was sent to all Polish surgical departments. Two hundred and sixty surgical departments returned the questionnaires.
Twenty-seven departments reported having performed bariatric operative or endoscopic procedures in 2016. The total number of procedures reported was 1958, the most popular being the laparoscopic sleeve gastrectomy (LSG). More than 99% of procedures were performed using laparoscopic techniques. The most common operations were: LSG (64.6%, n = 1032) and laparoscopic Roux-en-Y gastric bypass (LRYGB) (18.2%; n = 291), followed by one anastomosis gastric bypass (OAGB) (8.3%; n = 132) and laparoscopic adjustable gastric banding (LAGB) (7.3%; n = 117).
Registers of bariatric procedures provide information that helps in planning treatment and predicting possible complications. Adequate reporting of bariatric procedures is necessary to present the importance of the high incidence of obesity and the importance of its treatment. To collect reliable data, a national Polish bariatric surgery registry should be created.
Run and slow control system of the Belle II silicon vertex detector Irmler, C.; Aihara, H.; Aziz, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2020, Letnik:
958
Journal Article
Recenzirano
Odprti dostop
The Belle II Silicon Vertex Detector (SVD) was installed recently and has been prepared for physics run at SuperKEKB factory, Tsukuba, Japan. For a reliable operation and data taking of the SVD, a ...sophisticated and robust run and slow control system has been implemented, which utilizes the Experimental Physics and Industrial Control System (EPICS) framework. EPICS uses client/server and publish/subscribe techniques to communicate between the various sub-systems and computers. The information exchange between the different pieces of software and computers is done by process variables (PVs). These PVs are provided by input/output controllers (IOCs), which communicate and interface with the hardware components. The Belle II SVD slow and run control comprises five groups of subsystems, which are SVD DAQ controller, Flash ADC controller, environmental monitors and interlocks, power supplies and EPICS infrastructure services. In this paper we describe the tasks and the implementation of the individual sub-systems, the interaction between them and the global Belle II run and slow control as well as the first experience from commissioning and initial operation of the SuperKEKB accelerator.
An air-shower array consisting of 49 open huts with photomultiplier tubes viewing the night sky over a solid angle of about 1 steradian is described. The array is operating in conjunction with the ...HEGRA installation. The main objectives of the experiment are VHE to UHE γ-ray astronomy and a determination of the chemical composition of cosmic rays. The design principles, construction and performance in angular resolution, energy threshold and determination of shower parameters are discussed.
This paper shows the hardware and the procedure utilized to test all components of the readout system (cables, FADC boards, junction boards) of the Belle II Silicon Vertex Detector after the series ...production. For the FADC board special testing hardware and firmware were designed and created to check all digital and analog inputs and outputs as well as all data interconnections on the board. The main FPGA on the FADC board generates digital signals which are converted to periodic analog differential alternating voltages up to 40 MHz on the FADC board tester, which then are fed into the analog inputs of the FADC board. Histograms and scans of the samples are recorded by using random equivalent-time sampling or sequential equivalent-time sampling, allowing to characterize the behavior of the system with a much higher bandwidth than the ADCs could do with conventional measurements. Small changes of parameters of the assembly (like using a cable of different length) lead to significant changes of the measured values, creating a sensitive testing instrument. The shapes of the distributions are analyzed and compared to references by software which then decides if a test is passed or not.
The commissioning setup of the whole readout chain, with all the final components including the final detector, has been tested in three phases. The respective graphs of the signal-to-noise ratios of the strips of a detector module and histograms of the noise development of the whole detector show very high consistency of the SVD readout system.
Commissioning of the Belle II Silicon Vertex Detector Casarosa, G.; Aihara, H.; Aziz, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2020, Letnik:
958
Journal Article
Recenzirano
Odprti dostop
The Belle II experiment at the SuperKEKB collider of KEK (Japan) will accumulate 50 ab−1 of e+e- collision data at an unprecedented instantaneous luminosity of 8⋅ 1035 cm−2s−1, about 40 times larger ...than its predecessor. The Belle II vertex detector plays a crucial role in the rich Belle II physics program, especially for time-dependent measurements. It consists of two layers of DEPFET-based pixels and four layers of double sided silicon strip sensors (SVD detector). We report here results of the standalone commissioning of the SVD and highlights from the first cosmic runs acquired in Belle II. We also report on reconstruction performances of a reduced-scale version of the SVD operated during the accelerator commissioning in 2018.
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