Investigating the differential emission measure and energetics of microflares with combined SDO/AIA and RHESSI observations

An important question in solar physics is whether solar microflares, the smallest currently observable flare events in X-rays, possess the same energetic properties as large flares. Recent surveys have suggested that microflares may be less efficient particle accelerators than large flares, and hence contribute less nonthermal energy, which may have implications for coronal heating mechanisms. We therefore explore the energetic properties of microflares by combining Extreme Ultraviolet (EUV) and X-ray measurements. We present forward-fitting differential emission measure (DEM) analysis of 10 microflares. The fitting is constrained by combining, for the first time, high temperature RHESSI observations and flux data from SDO/AIA. Two fitting models are tested for the DEM; a Gaussian distribution and a uniform DEM profile. A Gaussian fit proved unable to explain the observations for any of the studied microflares. However, 8 of 10 events studied were reasonably fit by a uniform DEM profile. Hence microflare plasma can be considered to be significantly multi-thermal, and may not be significantly peaked or contain resolvable fine structure, within the uncertainties of the observational instruments. The thermal and non-thermal energy is estimated for each microflare, comparing the energy budget with an isothermal plasma assumption. From the multithermal fits the minimum non-thermal energy content was found to average approximately 30% of the estimated thermal energy. By comparison, under an isothermal model the non-thermal and thermal energy estimates were generally comparable. Hence, multi-thermal plasma is an important consideration for solar microflares that substantially alters their thermal and non-thermal energy content.Comment: 13 pages, 10 Figures, 2 tables. Accepted for publication in the Astrophysical Journa

S-matrices of non-simply laced affine Toda theories by folding

The exact factorisable quantum S-matrices are known for simply laced as well as non-simply laced affine Toda field theories. Non-simply laced theories are obtained from the affine Toda theories based on simply laced algebras by folding the corresponding Dynkin diagrams. The same process, called classical `reduction', provides solutions of a non-simply laced theory from the classical solutions with special symmetries of the parent simply laced theory. In the present note we shall elevate the idea of folding and classical reduction to the quantum level. To support our views we have made some interesting observations for S-matrices of non-simply laced theories and give prescription for obtaining them through the folding of simply laced ones.Comment: 26 pages, Latex2e, 4 figure

Parafermionic theory with the symmetry Z_N, for N even

Following our previous papers (hep-th/0212158 and hep-th/0303126) we complete the construction of the parafermionic theory with the symmetry Z_N based on the second solution of Fateev-Zamolodchikov for the corresponding parafermionic chiral algebra. In the present paper we construct the Z_N parafermionic theory for N even. Primary operators are classified according to their transformation properties under the dihedral group (Z_N x Z_2, where Z_2 stands for the Z_N charge conjugation), as two singlets, doublet 1,2,...,N/2-1, and a disorder operator. In an assumed Coulomb gas scenario, the corresponding vertex operators are accommodated by the Kac table based on the weight lattice of the Lie algebra D_{N/2}. The unitary theories are representations of the coset SO_n(N) x SO_2(N) / SO_{n+2}(N), with n=1,2,.... We suggest that physically they realise the series of multicritical points in statistical systems having a Z_N symmetry

Screening for non-communicable diseases

Background: This study was conducted to enumerate the results of screening for non-communicable diseases in the NCD clinic over a period of one year in a tertiary health centre.Methods: The results from screening tests conducted in the NCD clinic, for detecting hypertension, diabetes mellitus, breast cancer and cervical cancer, in Government tertiary care Hospital for Women, Chennai, were recorded. The flowchart and screening methods followed were those recommended by the NHM - NPCDCS. Data thus obtained was analyzed using standard statistical methods.Results: Of 42,519 women screened for common non communicable diseases - hypertension, diabetes mellitus, breast cancer and cervical cancer, nearly 5.55% women (n = 2359) had positive results, for any one of the diseases screened. Of 11,708 women screened for diabetes mellitus and 13,971 screened for hypertension, positive results were found in 856 women and 1,216 women respectively. Around 7,568 women were screened for cervical cancer and 175 women tested positive. A large number of 9,272 women were screened for breast cancer and 112 women had positive results. As per the guidelines, women who tested positive for screening tests were referred to the concerned departments in RGGGH.Conclusions: Nearly 42,519 women were screened for common non-communicable diseases (NCDs) - hypertension, diabetes mellitus, breast cancer and cervical cancer, and 5.55% women had positive test results for any one of the diseases screened. The screening revealed, 8.7% of women had raised blood pressure, 7.31% had raised blood sugar levels, 1.21% women had positive screening test results for breast cancer, and 2.31% women for cervical cancer

Major congenital malformations of foetus: a bane in pregnancy

Background: The aim of the study was to find out the numbers of women presenting with pregnancy complicating with major congenital anomalies of the fetus.Methods: This study was conducted over a period of fifteen months in the year 2018-2019. The types of congenital anomalies were that of the central nervous system, cardiac, renal, gastrointestinal, skeleto-muscular, hydrops foetalis, chromosomal, single umbilical artery and other multiple anomalies. Other variables regarding the age group of the mother, gravida, parity and gestational age at which the pregnancy was terminated was also noted.Results: A total of 212 pregnancies were diagnosed with major congenital anomalies of fetus and opted for termination. Malformations of the central nervous system (CNS) of fetus, formed the largest group of 56.6%, and fetal gastrointestinal malformations and fetal renal anomalies occupied the second major groups forming 11.8% and 11.3% respectively. The age group of women ranged between 23 years to 38 years. The largest group of pregnant women with fetal malformations were aged between 23-27 years. Primigravida with zero parity women were 60.4% of the total group of women with major fetal anomalies.Conclusions: Maximum number of congenital anomalies were seen in primigravida and para one mothers. Genetic counseling should be offered for women at clinics, before planning further pregnancy. Facilities should be made available for poor people from remote areas for early detection of congenital anomalies

The RHESSI Microflare Height Distribution

We present the first in-depth statistical survey of flare source heights observed by RHESSI. Flares were found using a flare-finding algorithm designed to search the 6-10 keV count-rate when RHESSI's full sensitivity was available in order to find the smallest events (Christe et al., 2008). Between March 2002 and March 2007, a total of 25,006 events were found. Source locations were determined in the 4-10 keV, 10-15 keV, and 15-30 keV energy ranges for each event. In order to extract the height distribution from the observed projected source positions, a forward-fit model was developed with an assumed source height distribution where height is measured from the photosphere. We find that the best flare height distribution is given by g(h) \propto exp(-h/{\lambda}) where {\lambda} = 6.1\pm0.3 Mm is the scale height. A power-law height distribution with a negative power-law index, {\gamma} = 3.1 \pm 0.1 is also consistent with the data. Interpreted as thermal loop top sources, these heights are compared to loops generated by a potential field model (PFSS). The measured flare heights distribution are found to be much steeper than the potential field loop height distribution which may be a signature of the flare energization process

Affine Toda field theory from tree unitarity

Elasticity property (i.e. no-particle creation) is used in the tree level scattering of scalar particles in 1+1 dimensions to construct the affine Toda field theory(ATFT) associated with root systems of groups $a_2^{(2)}$ and $c_2^{(1)}$. A general prescription is given for constructing ATFT (associated with rank two root systems) with two self conjugate scalar fields. It is conjectured that the same method could be used to obtain the other ATFT associated with higher rank root systems.Comment: 22 pages, 50 postscript figure files, Latex2e Added reference, typos corrected, minor text modificatio

Parafermionic theory with the symmetry Z_N, for N odd

We construct a parafermionic conformal theory with the symmetry Z_N, for N odd, based on the second solution of Fateev-Zamolodchikov for the corresponding parafermionic chiral algebra. Primary operators are classified according to their transformation properties under the dihedral group D_N, as singlet, doublet 1,2,...,(N-1)/2, and disorder operators. In an assumed Coulomb gas scenario, the corresponding vertex operators are accommodated by the weight lattice of the Lie algebra B_(N-1)/2. The unitary theories are representations of the coset SO_n(N) x SO_2(N) / SO_{n+2}(N), with n=1,2,... . Physically, they realise the series of multicritical points in statistical theories having a D_N symmetry.Comment: 34 pages, 1 figure. v2: note added in proo

Vaginal deliveries in a tertiary centre: a current profile

Background: A normal delivery is what every woman wishes to have. The objective of this study was to find out the maternal and neonatal outcome and background characteristics of women delivering vaginally in a tertiary care center in Chennai, South India.Methods: For this one-year study, with power above 80%, Parturition records were selected by computerized random numbers, for a calculated sample size. Salient demographic features such as age, residential background and religion were noted. Details of obstetric history, past and current, delivery and baby details and admission to NICU were analyzed. Acceptance of postpartum contraception was noted.Results: A total of 338 women delivered vaginally. Majority of 63%, were from urban background. Late referrals were 19.2% of women,38.5% women had antenatal complications. Primigravida were 49.7%. Nearly 91.4% of women delivered naturally. Previous pregnancy loss was noted in 14.8%. Term deliveries were in 72% of women, and 2.7% of women delivered twins. Average birth weight among primi was 2.5kg and in multi it was 2.8 kg. There were no maternal deaths. Perinatal deaths of 2.96%, of which 90% were preterm births, and all among babies with birth weight below 1.5 kg.Conclusions: The larger majority of 91.4% of women had natural vaginal delivery. Primigravida were 49.7%, and 63% were from urban background. Antenatal complications, obstetric, medical or other complications were noted in 38.5 % of women. Most often observed complications were Gestational hypertension, Gestational diabetes, and Hypothyroidism. NICU care was required for 18% of babies. Preterm births were16.6%. Perinatal deaths were seen in 2.96% of babies. There were no maternal deaths