An Integrated Distributed Storage Design Offering Data Retrievability and Recoverability Using Soft Decision Decoding of Block Codes

Active distributed storages need to assure both consistency and dynamic data support, in addition to availability, confidentiality and resiliency. Further, since storage durability suffers in untrusted and unreliable environments, it becomes crucial to (a) select the most reliable set of servers to assure data retrievability and (b) dynamically identify errant servers and restore the data to ensure data recoverability. We address the issues of concurrency, consistency, dynamic data support, data share repair, and trust management in providing persistent storage and access. The paper focuses primarily on erasure coded distributed storages (storages employing erasure coding for data dispersal). Integration of Quorum based approach using Notification propagation, with a reliability model based on server trust-reputation forms the comprehensive design proposed. Treating servers and their data shares equally at data reconstructions during data retrievals is rather inadequate in untrusted environments. The design provides a suitable platform for use of Soft Decision Decoding to overcome this inadequacy. The design has been validated by the simulation, study, and analysis carried out for Reed Solomon coded storage with varying levels of resiliency and concurrency. The proposed design can be suitably adapted in typical distributed information storages catering to global networked audience in public, untrusted, and unreliable operating environments.</p

A retrospective analysis of mid trimester termination of pregnancies for fetal congenital malformations at tertiary care hospital

Background: This study was conducted to analyse the spectrum of fetal anomalies as a cause of pregnancy termination in a tertiary care hospital.Methods: This retrospective study includes antenatal women with fetal anomalies diagnosed by an ultrasound (USG) and admitted in Chettinad Hospital and Research Institute, Kelambakkam from January 2018 to January 2020 for termination of pregnancy. Data was collected from hospital records and analysed.Results: Gestational age of women with fetal congenital anomalies ranged from 13 to 21 weeks. Pregnancy termination, was performed between 17-19 weeks of gestation in 41% of patients, between 13-15 weeks and 19-21 weeks in 23% of women respectively. Congenital fetal anomalies resulting in termination of pregnancy were CNS, musculoskeletal, cardiovascular, renal and multiple anomalies. CNS abnormalities was a major cause of termination of pregnancy which includes meningomyelocele, spina bifida, acrania, anencephaly.Conclusions: In our study conducted at our tertiary care center, CNS abnormalities were the major cause of mid trimester termination of pregnancies, followed by musculoskeletal abnormalities being second most common cause

Glycerol conversion to 1, 3-Propanediol is enhanced by the expression of a heterologous alcohol dehydrogenase gene in Lactobacillus reuteri

In this work, Lactobacillus reuteri has been metabolically engineered for improving 1, 3-propanediol (1, 3-PD) production by the expression of an Escherichia coli alcohol dehydrogenase, yqhD, that is known to efficiently convert the precursor 3-hydroxypropionaldehyde (3-HPA) to 1, 3-PD. The engineered strain exhibited significantly altered formation rates for the product and other metabolites during the fermentation. An increase in the 1, 3-PD specific productivity of 34% and molar yield by 13% was achieved in the clone, relative to the native strain. A concomitant decrease in the levels of toxic intermediate, 3-HPA, was observed, with the specific productivity levels being 25% lesser than that of the native strain. Interestingly, the recombinant strain exhibited elevated rates of lactate and ethanol formation as well as reduced rate of acetate production, compared to the native strain. The preferential utilization of NADPH by YqhD with a possible decrease in the native 1, 3-PD oxidoreductase (NADH-dependent) activity, could have resulted in the diversion of surplus NADH towards increased lactate and ethanol productivities

Assessment of Population Exposure to Coarse and Fine Particulate Matter in the Urban Areas of Chennai, India

Research outcomes from the epidemiological studies have found that the course (PM 10 ) and the fine particulate matter (PM 2.5 ) are mainly responsible for various respiratory health effects for humans. The population-weighted exposure assessment is used as a vital decision-making tool to analyze the vulnerable areas where the population is exposed to critical concentrations of pollutants. Systemic sampling was carried out at strategic locations of Chennai to estimate the various concentration levels of particulate pollution during November 2013-January 2014. The concentration of the pollutants was classified based on the World Health Organization interim target (IT) guidelines. Using geospatial information systems the pollution and the high-resolution population data were interpolated to study the extent of the pollutants at the urban scale. The results show that approximately 28% of the population resides in vulnerable locations where the coarse particulate matter exceeds the prescribed standards. Alarmingly, the results of the analysis of fine particulates show that about 94% of the inhabitants live in critical areas where the concentration of the fine particulates exceeds the IT guidelines. Results based on human exposure analysis show the vulnerability is more towards the zones which are surrounded by prominent sources of pollution

Recent developments of SOLEROO: Australia's first high energy radioactive Ion Beam capability

The first measurements of the Australian National University's new radioactive ion beam capability were carried out using elastic scattering of a 8Li radioactive beam from a 197Au target. The purpose of this experiment was to test the radioactive ion beam capability as a complete system, which uses a pair of twin position-sensitive parallel plate avalanche counters as tracking detectors along with a highly pixelated double sided Si detector array. The tracking detector system allows us to have extremely high purity secondary radioactive ion beams by electronically tagging the reaction products of interest, thus allowing complete separation from the unwanted contaminant beam species of similar mass and charge. Here, some recent developments and characteristics of this system are presented

Investigating energy dissipation through nucleon transfer reactions

Nucleon and cluster transfer probabilities have been measured in the collisions of 16,18O, 19F with 204,208Pb, 209Bi for charge stripping channels down to ΔZ = - 3. Strong evidence of correlated nucleon transfer has been observed in particular channels, and neighbouring systems are seen to differ significantly in their behaviour. New measurements were made using an improved ΔE-E telescope. The back-scattered projectilelike fragments were measured in the telescope at θlab = 160.6°, and in combination with monitor detectors at forward angles allowed determination of absolute transfer probabilities. The improved design allows isotopic yields to be measured with greater precision

Evolution of signatures of quasifission in reactions forming curium

Background: Quasifission, a fission-like reaction outcome in which no compound nucleus forms, is an important competitor to fusion in reactions leading to superheavy elements. The precise mechanisms driving the competition between quasifission and fusio

Fission cross sections as a probe of fusion dynamics at high angular momentum

Background: Fusion of heavy nuclei requires energy dissipation to trap the system inside the capture barrier. At high angular momentum, the centrifugal potential causes the barrier radius to reduce, which may lead to energy dissipation outside the barrier, affecting the fusion angular momentum distributions and thus the capture cross sections. Purpose: To investigate the sensitivity of fusion-fission cross sections as a probe of fusion dynamics at high angular momentum. Method: Fission of the compound nucleus Yb164 formed by three different fusion reactions, namely, O16+Sm148, Si28+Ba136, and Ca40+Sn124, was measured at four beam energies well above their respective capture barriers. Fission cross sections were extracted from the measured fission fragment angular distributions and compared with model calculations of fusion and subsequent fission. Fusion and evaporation residue cross sections available in the literature for the same or similar reactions were used to guide model calculations and obtain the fusion angular momentum distributions. Results: The measured fission characteristics were found to be consistent with fusion-fission, as expected, justifying the use of the statistical model to calculate fission cross sections for each reaction. Significantly different fission cross-section predictions were obtained from calculations using angular momentum distributions corresponding to different coupling schemes and different diffuseness parameter of the nuclear potential. A large diffuseness parameter (0.65 fm) of the nuclear potential was observed to give the best reproduction of both the experimental fusion as well as fission cross sections. Conclusions: Experimental fission cross sections provide a stringent constraint to the fusion model calculations and thus prove to be a sensitive probe for understanding fusion dynamics at high angular momentum. This is shown in the present work by a simultaneous analysis of the fusion and fission cross sections for systems where fission cross sections form a small fraction of the fusion cross section and where noncompound nuclear processes are not a dominant competing channel. Observations from this work also suggest the requirement of evaporation residue as well as fission cross sections of higher precision than those generally available for drawing quantitative conclusions.The support from Australian Research Council through Grants No. DE140100784, No. DP160101254, No. FL110100098, and No. FT120100760 and support for the HIAF accelerator operations from the Australian Federal Government NCRIS program is gratefully acknowledged

Energy dissipation and suppression of capture cross sections in heavy ion reactions

Background: At energies above the capture barrier, coupled-channels (CC) calculations with a standard nuclear potential diffuseness (0.65 fm) increasingly overestimate experimental capture cross section as the charge product (Z1Z2) of the colliding nuclei increases. It has been suggested this may be linked to energy dissipation outside the capture barrier. Purpose: We investigate quantitatively the role of energy dissipation in suppressing capture in heavy ion fusion reactions. Method: The yields of sequential fission, including that resulting from deep inelastic collisions, and of fission following capture were determined simultaneously for collisions of 18O, 30Si, 34S, and 40Ca + 232Th at a range of energies around the respective capture barriers. Results: The ratio of experimental to CC capture cross sections was found to decrease with increasing Z1Z2. Conversely, the ratio of sequential fission to capture-fission increased with increasing Z1Z2. The sum of sequential and capture fission agrees quite well with the CC cross sections. Conclusions: The experimental capture fission and sequential fission cross sections, and their comparison with CC calculations, give a consistent picture that the increase in density overlap at the capture barrier with increasing Z1Z2 of the colliding nuclei is correlated with increasing energy dissipative processes. These compete increasingly strongly with capture as the Z1Z2 of the reaction increases. For the 40Ca reaction, the total fission yield exceeds expectations from capture model calculations, indicating that deep inelastic processes occur both from trajectories that would have led to capture and also from more peripheral trajectories

Embryogenesis in Sedum acre L.: structural and immunocytochemical aspects of suspensor development

The changes in the formation of both the actin and the microtubular cytoskeleton during the differentiation of the embryo-suspensor in Sedum acre were studied in comparison with the development of the embryo-proper. The presence and distribution of the cytoskeletal elements were examined ultrastructurally and with the light microscope using immunolabelling and rhodamine-phalloidin staining. At the globular stage of embryo development extensive array of actin filaments is present in the cytoplasm of basal cell, the microfilament bundles generally run parallel to the long axis of basal cell and pass in close to the nucleus. Microtubules form irregular bundles in the cytoplasm of the basal cell. A strongly fluorescent densely packed microtubules are present in the cytoplasmic layer adjacent to the wall separating the basal cell from the first layer of the chalazal suspensor cells. At the heart-stage of embryo development, in the basal cell, extremely dense arrays of actin materials are located near the micropylar and chalazal end of the cell. At this stage of basal cell formation, numerous actin filaments congregate around the nucleus. In the fully differentiated basal cell and micropylar haustorium, the tubulin cytoskeleton forms a dense prominent network composed of numerous cross-linked filaments. In the distal region of the basal cell, a distinct microtubular cytoskeleton with numerous microtubules is observed in the cytoplasmic layer adjacent to the wall, separating the basal cell from the first layer of the chalazal suspensor cells. The role of cytoskeleton during the development of the suspensor in S. acre is discussed