Observations of Multiple Surges Associated with Magnetic Activities in AR10484 on 25 October 2003

We present a multiwavelength study of recurrent surges observed in H{\alpha}, UV (SOHO/EIT) and Radio (Learmonth, Australia) from the super-active region NOAA 10484 on 25 October, 2003. Several bright structures visible in H{\alpha} and UV corresponding to subflares are also observed at the base of each surge. Type III bursts are triggered and RHESSI X-ray sources are evident with surge activity. The major surge consists of the bunches of ejective paths forming a fan-shape region with an angular size of (\approx 65\degree) during its maximum phase. The ejection speed reaches upto \sim200 km/s. The SOHO/MDI magnetograms reveal that a large dipole emerges east side of the active region on 18-20 October 2003, a few days before the surges. On October 25, 2003, the major sunspots were surrounded by "moat regions" with moving magnetic features (MMFs). Parasitic fragmented positive polarities were pushed by the ambient dispersion motion of the MMFs and annihilated with negative polarities at the borders of the moat region of the following spot to produce flares and surges. A topology analysis of the global Sun using PFSS shows that the fan structures visible in the EIT 171 A images follow magnetic field lines connecting the present AR to a preceding AR in the South East. Radio observations of type III bursts indicate that they are coincident with the surges, suggesting that magnetic reconnection is the driver mechanism. The magnetic energy released by reconnection is transformed into plasma heating and provides the kinetic energy for the ejections. A lack of a radio signature in the high corona suggests that the surges are confined to follow the closed field lines in the fans. We conclude that these cool surges may have some local heating effects in the closed loops, but probably play a minor role in global coronal heating and the surge material does not escape to the solar wind.Comment: Accepted for the Publication in ApJ; 25 pages, 10 Figures, and 1 Tabl

Interaction of Two Filament Channels of Different Chiralities

We present observations of interactions between the two filament channels of different chiralities and associated dynamics that occurred during 2014 April 18 -- 20. While two flux ropes of different helicity with parallel axial magnetic fields can only undergo a bounce interaction when they are brought together, the observations at the first glance show that the heated plasma is moving from one filament channel to the other. The SDO/AIA 171 A observations and the PFSS magnetic field extrapolation reveal the presence of fan-spine magnetic configuration over the filament channels with a null point located above them. Three different events of filament activations, partial eruptions, and associated filament channel interactions have been observed. The activation initiated in one filament channel seems to propagate along the neighbour filament channel. We believe that the activation and partial eruption of the filaments bring the field lines of flux ropes containing them closer to the null point and trigger the magnetic reconnection between them and the fan-spine magnetic configuration. As a result, the hot plasma moves along the outer spine line toward the remote point. Utilizing the present observations, for the first time we have discussed how two different-chirality filament channels can interact and show interrelation.Comment: 30 pages, 13 figures, Accepted for Publication in Ap

Performance of Amblypharyngodon mola with Barbodes gonionotus, Cyprinus carpio and Macrobrachium rosenbergii in rice-fish culture system

An experiment was conducted to assess the performance of mola (Amblyphmyngodon mola) in rice fish culture system with freshwater prawn Macrobrachium rosenbergii), Thai silver barb (Bm·bades ganianotus) and common carp (Cyprinus cmpia) for a period of 4 months at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh, Bangladesh. Four treatments viz., treatment-I (T1) with A. mala and M. rosenbergii; treatmen t-II (T2) with A. mala, M. rosenbergii and B. gonianatus ; treatmentIII (T3) with A. mala, 1Vf. rosenbergii and C. cmpia, and treatment- IV (T4) as control (without fish) were used in triplicate. All treatments were equally fertilized with urea (200 kg/ha), TSP (150 kg/ha) and MP (75 kg/ha). The mean values of water quality parameters viz., temperature, dissolved oxygen, pH, nitrate-nitrogen showed a very small variations among different treatments, but phosphate-phosphorus and chlorophyll-a were relatively higher in T4 without fish (i.e., control). The fish production of 480.5 kg/ha in T3 was significantly higher than that of 355.6 kg/ha T2 and 223.8 kg/ha in T 1• The values of soil organic matter, total-nitrogen, phosphorus and potassium at harvest were significantly (P<0.05) higher in the treatments with fish than without fish, but pH did not show any significant differences. The yield of rice grain and straw was also obtained significantly (P<0.05) higher in the treatments with fish. The increase in grain was higher over the control by 11.81%, 9.41% and 14.76% and that in straw was by 9.83%, 4.77% and 13.29% in Tl> T2, and T3 respectively

Evolution of Solar Magnetic Field and Associated Multi-wavelength Phenomena: Flare events on 20 November 2003

We analyze H-alpha images, soft X-ray profiles, magnetograms, extreme ultra-violet images and radio observations of two homologous flare events (M1.4/1N and M9.6/2B) on 20 November 2003 in the active region NOAA 10501 and study properties of reconnection between twisted filament systems, energy release and associated launch of coronal mass ejections (CMEs). During both events twisted filaments observed in H-alpha approached each other and initiated the flare processes. However, the second event showed the formation of cusp as the filaments interacted. The rotation of sunspots of opposite polarities, inferred from magnetograms likely powered the twisted filaments and injection of helicity. Along the current sheet between these two opposite polarity sunspots, the shear was maximum, which could have caused the twist in the filament. At the time of interaction between filaments, the reconnection took place and flare emission in thermal and non-thermal energy ranges attained the maximum. The radio signatures revealed the opening of field lines resulting from reconnection. The H-alpha images and radio data provide the inflow speed leading to reconnection and the scale size of particle acceleration region. The first event produced a narrow and slow CME, whereas the later one was associated with a fast full halo CME. The halo CME signatures observed between Sun and Earth using white-light and scintillation images and in-situ measurements indicated the magnetic energy utilized in the expansion and propagation. The magnetic cloud signature at the Earth confirmed the flux rope ejected at the time of filament interaction and reconnection.Comment: 22 pages, 16 figures, Accepted for the publication in Astrophysical Journal (APJ

The Electrokinetic Stabilization (EKS) Green Approach Towards Improving the Geotechnical Properties of the Gulf Sabkha Soil at Rabigh, Saudi Arabia

Objectives: Sabkha soil is widely formed in the Arabian Gulf in the Kingdom of Saudia Arabia, particularly along the coastline. Over the past 25 years, numerous studies have been conducted to understand and characterize sabkha soil and increase its strength and durability. To enhance the geotechnical properties of Sabkha soil using an environmentally friendly electrokinetic stabilization method. From a geotechnical perspective, the construction process heavily depends on improving weak soil strength, durability, and treatment cost. The presence of water, high salinity, low shear strength, and low specific gravity are the soft geotechnical features that need to be enhanced before any construction on sabkha soil. Methods/Analysis: The electrokinetic stabilization method was applied to extract salty particles and enhance the geotechnical properties of sabkha soil. The voltage gradient of 40 V was applied for 1, 3, and 7 days using stainless steel electrodes. Findings: The result showed an outstanding improvement of sabkha soil geotechnical properties where the shear strength was increased from 116 to 165, 230, and 360 kPa for Rabigh I (RI), 122 to 155, 254, and 371 kPa for Rabigh II (RII), and for Rabigh III (RIII), the shear strength was improved up to 405 kPa. The moisture content decreased from 34.5 to 16.8% for RI, 35.2 to 15.9% for RII, and 37.5 to 14.7% for RIII. Novelty and applications: Experimental results demonstrated that all parameters were improved massively by increasing the voltage gradient and operational time. This technique is highly recommended to strengthen weak soil and improve geotechnical properties

Adverse effects of parenteral dexamethasone in the treatment of pemphigus vulgaris

Background: Pemphigus vulgaris is associated with high morbidity as well as significant mortality rate. Today the risk of death in pemphigus from the side effect of oral prednisolone is greater than risk of death from the disease itself. Objec­tive: To observe the adverse effects of parenteral dexamethasone compared with oral prednisolone in the treatment of pemphigus vulgaris. Methods: An interventional study was carried out in the department of Dermatology and Venereol­ogy, Bangabandu Sheikh Mujib Medical University, Dhaka, Bangladesh. Total number of patients was thirty and among them fifteen patients were treated with parenteral dexamethasone (Group-A) and other fifteen were treated with oral prednisolone (Group-B). Results: The study showed statistically significant differences of skin lesion as well as mucosal lesion of pemphigus after 6 weeks of therapy between of two groups (P&lt;0.05). The most common adverse effects were increased body weight(40%), increased appetite(40%), and puffy face(40%) in dexamethasone group. In prednisolone group, these side effects were 60% of the subjects. Other side effects in dexamethasone group were hyperglycemia (33.33%), hypertension (26.66%), and sleep disturbance (13.33%). In prednisolone group, other side effects were hyperglycemia(33.33%), hypertension(40%), gastritis (33.33%), nausea, vomiting (13.33%) in each , reactivation of tuberculosis, herpes zoster infection, sleep disturbance, and mood change were 6.66% in each group. Conclusion: In the light of the findings of the study, we conclude that each of the treatment of dexamethasone group and prednisolone group is individually effective and safe in the treatment of pemphigus vulgaris but adverse effects are less in parenteral dexamethasone group than oral prednisolone group. So parenteral dexamethasone can be used as an alternative drug in the treatment of pemphigus vulgaris

On the Triggering of M-Class Solar Flare due to Loop-loop Interaction in AR NOAA 10875

We present multiwavelength analysis of an M7.9 /1N solar flare which occurred on 27 April 2006 in AR NOAA 10875. The flare was triggered due to the interaction of two loop systems. GOES soft X-ray and TRACE 195 {\AA} image sequences show the observational evidences of 3-D X-type loop-loop interaction with converging motion at the interaction site. We found the following characteristics during the loop- loop interaction: (i) a short duration/impulsive flare obeying the Neupart effect, (ii) double peak structure in radio flux profiles (in 4.9 and 8.8 GHz), (iii) quasi-periodic oscillations in the radio flux profiles for the duration of \sim3 min, (iv) absence of CME and type III radio burst. The above characteristics observed during the flare are in agreement with the theory and simulation of current loop coalescence by Sakai et al. (1986). These are unique multiwavelength observations, which provide the evidences of loop-loop interaction and associated triggering of solar flare without CME.Comment: 7 pages, 4 figures, to be appear in the Proc. of the 1st Asian-Pacific Solar Phys. Meetin