3,475 research outputs found

    Fine structures in the atmosphere above a sunspot umbra

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    We present simultaneous photospheric and chromospheric observations of the trailing sunspot in NOAA 10904, obtained with the Swedish Solar Telescope (SST) La Palma, Canary Islands. Time series of high resolution \ion{Ca}{ii}\,HH images show transient jet-like structures in sunspot umbrae are elongated, which we call umbral microjets. These jets are directed roughly parallel to nearby penumbral microjets, suggesting that they are aligned with the background magnetic field. In general, first a bright dot-like structure appears, from which a jet later emerges, although some jets appear without an associated chromospheric dot. Bright photospheric umbral dots are associated with umbral microjets arising in the outer umbra. Nevertheless, a one-to-one correspondence between jet-like events and underlying umbral dots is not seen. They are typically less than 1\arcsec ~long and less than 0\farcs3 wide. The typical lifetime of umbral microjets is around one minute. The brightness of these structures increases from the center of the umbra towards the umbra-penumbra boundary along with the brightness of the local background.Comment: 5 pages, 6 figures. Accepted for publication in A&A Lette

    Understanding the degeneracies in NOν\nuA data

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    The combined analysis of νμ\nu_\mu disappearance and νe\nu_e appearance data of NOν\nuA experiment leads to three nearly degenerate solutions. This degeneracy can be understood in terms of deviations in νe\nu_e appearance signal, caused by unknown effects, with respect to the signal expected for a reference set of oscillations parameters. We define the reference set to be vacuum oscillations in the limit of maximal θ23\theta_{23} and no CP-violation. We then calculate the deviations induced in the νe\nu_e appearance signal event rate by three unknown effects: (a) matter effects, due to normal or inverted hierarchy (b) octant effects, due to θ23\theta_{23} being in higher or lower octant and (c) CP-violation, whether δCP∼−π/2\delta_{CP} \sim - \pi/2 or δCP∼π/2\delta_{CP} \sim \pi/2. We find that the deviation caused by each of these effects is the same for NOν\nuA. The observed number of νe\nu_e events in NOν\nuA is equivalent to the increase caused by one of the effects. Therefore, the observed number of νe\nu_e appearance events of NOν\nuA is the net result of the increase caused by two of the unknown effects and the decrease caused by the third. Thus we get the three degenerate solutions. We also find that further data by NOν\nuA can not distinguish between these degenerate solutions but addition of one year of neutrino run of DUNE can make a distinction between all three solutions. The distinction between the two NH solutions and the IH solution becomes possible because of the larger matter effect in DUNE. The distinction between the two NH solutions with different octants is a result of the synergy between the anti-neutrino data of NOν\nuA and the neutrino data of DUNE.Comment: Published version v2; with minor changes to v

    Tensions between the appearance data of T2K and NOvA

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    The long baseline neutrino experiments, T2K and NOvA, have taken significant amount of data in each of the four channels: (a) νμ\nu_\mu disappearance, (b) νˉμ\bar\nu_\mu disappearance (c) νe\nu_e appearance and (d) νˉe\bar\nu_e appearance. There is a mild tension between the disappearance and the appearance data sets of T2K. A more serious tension exists between the νe\nu_e appearance data of T2K and the νe/νˉe\nu_e / \bar\nu_e appearance data of NOvA. This tension is significant enough that T2K rules out the best-fit point of NOvA at 95%95\% confidence level whereas NOvA rules out T2K best-fit point at 90%90\% confidence level. We explain the reason why these tensions arise. We also do a combined fit of T2K and NOvA data and comment on the results of this fit.Comment: matches the published versio

    Waves as the source of apparent twisting motions in sunspot penumbrae

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    The motion of dark striations across bright filaments in a sunspot penumbra has become an important new diagnostic of convective gas flows in penumbral filaments. The nature of these striations has, however, remained unclear. Here we present an analysis of small scale motions in penumbral filaments in both simulations and observations. The simulations, when viewed from above, show fine structure with dark lanes running outwards from the dark core of the penumbral filaments. The dark lanes either occur preferentially on one side or alternate between both sides of the filament. We identify this fine structure with transverse (kink) oscillations of the filament, corresponding to a sideways swaying of the filament. These oscillations have periods in the range of 5-7 min and propagate outward and downward along the filament. Similar features are found in observed G-band intensity time series of penumbral filaments in a sunspot located near disk center obtained by the Broadband Filter Imager (BFI) on board {\it Hinode}. We also find that some filaments show dark striations moving to both sides of the filaments. Based on the agreement between simulations and observations we conclude that the motions of these striations are caused by transverse oscillations of the underlying bright filaments.Comment: Accepted for publication in Astrophysical Journal on 8th April 201

    Status of plankton diversity and biological productivity of Sahastradhara stream at Uttarakhand, India

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    The present contribution encompasses on plankton and biological productivity as ecological indicator for identifying the ecological quality of Sahastradhara stream (between 27 km stream stretches), located in the Doon Valley of Garhwal region in India. Monthly sampling from all the sampling sites was made for a period of 12 months (May 2009 – April 2010) at 9:00-11: 00 AM. A total of 40 taxa from different classes of plankton and zooplankton were reported. The phytoplankton (32 sp.) was found being the most abundant taxa than zooplankton (9 sp.) inSahastradhara stream. Fluctuation in the phytoplankton density was recorded highest (1536 unit/l) during winter and lowest (20 unit/l) during monsoon. Zooplanktons were reported to be maximum (147 unit/l) during summer and minimum (3 unit/l) during monsoon. The total diatoms were reported highest (1022unit/l) during starting the winter and lowest (4 unit/l) during monsoon. Green algae and blue green algae were reported to be maximum during winter and minimum during summer. The Shannon-wiener diversity index calculated for the density ofBacillariophyceae (0.2180-0.366), Chlorophyceae (0.208-0.367) and Cyanophyceae (0.391-0.366) and correlation was made between Plankton biomass and physico-chemical parameters to analyses the relative features of the both variables. The density of plankton and biological productivity were influenced by disturbances in the photic zone and indiscriminate anthropogenic activities for tourist development resulted aquatic habitat degradation in stream ecosystem

    Role of hysterolaparoscopy in the evaluation of female infertility in a tertiary care centre

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    Background: Infertility is one of the most important and underappreciated reproductive health problems in developing countries. Inability to conceive bears a social stigma which causes societal repercussion and personal suffering. The advent of hysterolaparoscopy have redefined the evaluation and treatment of infertile women. Study aimed to assess the role of hysterolaparoscopy in the evaluation of female infertility.Methods: This prospective observational study was done in the department of obstetrics and gynaecology, Gandhi Medical College, Sultania Zanana Hospital, Bhopal, during the period between 1st December 2016 to 30th November 2017. 104 infertile patients either with primary or secondary infertility were included after thorough evaluation.Results: Out of 104 infertile patients, 82(78.8%) women had primary infertility and rest 22(21.1%) women had secondary infertility. In primary infertility group, most common laparoscopic finding was PCOD in 24(29%) women and in secondary infertility group, tubal blockage was seen in 9(40%) women. The most common pathology seen in hysteroscopy was submucous fibroid in 6(7.3%) women with primary infertility, whereas in secondary infertility group, synechiae was found in 2(9%) patients and septum was seen in 1(4.5%) patient. Out of 104 patients, 33 (31.7%) patients underwent various interventions. The most common intervention was ovarian drilling for PCOS in 21(63.3%) patients followed by hysteroscopic cannulation in 5(15.5%) patients.Conclusions: Hysterolaparoscopy is a very useful tool that can detect various structural abnormalities in multiple sites like uterus, tubes, ovaries and peritoneal cavity in the same sitting. When done by experienced hands and proper selection of patients, hysterolaparoscopy can be considered as a definitive investigative procedure for evaluation of female infertility
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