Lesser Known Ethnomedicinal Plants of Alagar Hills, Madurai District of Tamil Nadu, India

The ethnobotanical uses of plant species viz. Embelia basal (Roxb.) DC., Gymnema lactiferum R.Br., Ophiorrhiza mungos L., and Syzygium alternifolium (Wight) Walp. were recorded from Alagar hills of Madurai district, Tamil Nadu

The optimal schedule for pulsar timing array observations

In order to maximize the sensitivity of pulsar timing arrays to a stochastic gravitational wave background, we present computational techniques to optimize observing schedules. The techniques are applicable to both single and multi-telescope experiments. The observing schedule is optimized for each telescope by adjusting the observing time allocated to each pulsar while keeping the total amount of observing time constant. The optimized schedule depends on the timing noise characteristics of each individual pulsar as well as the performance of instrumentation. Several examples are given to illustrate the effects of different types of noise. A method to select the most suitable pulsars to be included in a pulsar timing array project is also presented.Comment: 16 pages, 6 figures, accepted by MNRA

Spin frequency evolution and pulse profile variations of the recently re-activated radio magnetar XTE J1810-197

After spending almost a decade in a radio-quiet state, the Anomalous X-ray Pulsar XTE J1810-197 turned back on in early December 2018. We have observed this radio magnetar at 1.5 GHz with ~daily cadence since the first detection of radio re-activation on 8 December 2018. In this paper, we report on the current timing properties of XTE J1810-197 and find that the magnitude of the spin frequency derivative has increased by a factor of 2.6 over our 48-day data set. We compare our results with the spin-down evolution reported during its previous active phase in the radio band. We also present total intensity pulse profiles at five different observing frequencies between 1.5 and 8.4 GHz, collected with the Lovell and the Effelsberg telescopes. The profile evolution in our data set is less erratic than what was reported during the previous active phase, and can be seen varying smoothly between observations. Profiles observed immediately after the outburst show the presence of at least five cycles of a very stable ~50-ms periodicity in the main pulse component that lasts for at least tens of days. This remarkable structure is seen across the full range of observing frequencies.Comment: 9 pages, 7 figures, updated with additional analysis of the 50-ms oscillation, accepted for publication in MNRA

Yield and quality improvement in Bt cotton through foliar application of trifloxystrobin and tebuconazole

In agriculture, fungi can cause serious damage, resulting in critical losses of yield, quality and profit. Fungicides help in reducing the damage caused by fungus, reduce the yield loss and play a major role in quality improvement. The present investigation was carried out at Tamil Nadu Agricultural University to evaluate the influence of trifloxystrobin 50% + tebuconazole 25% (Nativo 75WG) on the yield and quality improvement on Bunny hybrid Bt cotton.  Nativo 75WG was applied on the leaves of cotton plants at 40-60 (DAS) and 60-80 (DAS) at the concentration of 250, 300, 350 g/ha and Carbendazim @ 500 g/ha.  The observations recorded were related to yield and quality attributes in all treatments. The application of Nativo @ 300 g/ha showed a significant increase in boll weight (4.86 g), lint yield per boll (3.86 g boll-1) and lint per plant (138.48 g plant -1) than other treatments. With respect to seed cotton yield and harvest index (0.37 %), the Nativo @ 300 g/ha registered a higher yield (20.2 %) and HI than control under the irrigated situation. Foliar application of treatments during the flowering stage (40-60 DAS) and boll formation stages (60-80 DAS) had increased the quality parameters such as fiber length (2.5% staple length, 50 % staple length) and fiber strength. Further, the foliar spray of  Nativo @ 300 g/ha applied to bunny hybrid Bt cotton had resulted in a higher yield (2920.15 kg ha-1) due to an increase in leaf area index, greenness of leaf and higher dry matter production of the plant

Chemical Composition and Antioxidant Activity of Heracleum sprengelianum (Wight and Arnott) Essential Oils Growing Wild in Peninsular India

Abstract The essential oils, isolated by hydrodistillation from the leaves, seeds and rhizomes of Heracleum sprengelianum (Wight and Arnott), collected from the Western Ghats of Peninsula India, were analyzed by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC-MS). The antioxidant property of these oils was tested, with and without peroxidation inducer, through the egg yolk-based Thiobarbituric Acid Reactive Substances assay (TBARS assay) and in the concentrations of 50, 100, 250 and 500 mg/L. β-Pinene, 1,8-Cineole, β-Phellandrene and ρ-Cymen-8-ol were the main components of H. sprengelianum leaves, seeds and rhizomes essential oils. The oils demonstrated the antioxidant capacity in the absence of radical inducer 2, 20-azobis-(2-amidinopropane) dihydrochloride (ABAP), mainly that of H. sprengelianum at 250 and 500 mg/L, comparable in some cases to that of α-tocopherol and butylated hydroxytoluene (BHT). The presence of ABAP diminished the antioxidant ability of all tested essential oils, leaf oils of H. sprengelianum still showing the highest antioxidant capacity at 500 mg/L. At 250 and 500 mg/L for BHA, and 500 mg/L for α-tocopherol, the antioxidant capacity significantly increased in the presence of ABAP

Influence of nutrients and plant growth regulators on growth parameters and yield of Pigeonpea (Cajanus cajan (L.) Millsp.)

Pigeonpea is the second most important pulse crop after chickpea in India. The yield of pigeonpea is very low due to indeterminate growth habit and poor source-sink relationship. Plant growth regulators are known to influence the source-sink relationship and stimulate the translocation of photo-assimilates thereby helping in effective flower formation, fruit and seed development and ultimately enhance productivity of the crops. With this background, a field experiment was conducted with pigeonpea (CO Rg 7) under irrigated condition in Tamil Nadu Agricultural University, Coimbatore. An experiment was aimed at determining the effect of various nutrients and growth-promoting hormones on the growth parameters and yield of pigeonpea (Cajanus cajan (L.) Millsp.). The Factorial Randomised Block Design was used in the field trial and was replicated three times. At the vegetative stage, the treatments included foliar sprays of growth inhibitors such as M2-Mepiquat chloride (MC) @ 500 pp, M3-Chlormequat chloride (CC) @ 500 ppm and M1- Control. At flower initiation and 15 days later, various plant growth regulators, such as T2-SA (100 ppm), T3-BR (0.1 ppm), T4-Napthyl acetic acid (40 ppm), T5-Nutrients (ZnSO4 @ 0.5 percent + H3BO3 @ 0.3 percent, T6-Mono Ammonium Phosphate @ 2 percent, and T7-TNAU Pulse Wonder @ 1 percent), T8-Nutrient consortia I (1%) and T9-Nutrient consortia II (1%), were used. Among the treatments, the combination of Chlormequat chloride and nutrient consortia treatments (M3T8&M3T9) had better performances in growth parameters and yield of pigeonpea (CO Rg 7). Foliar application of M3T8-Chlormequat chloride and Nutrient consortia I (1%) resulted significantly (P<0.05) in the highest Total dry matter production (64.85; 82.96 g plant-1), Leaf area (1629; 1873 cm-2 plant-1), Leaf area index (1.358; 1.561), Specific leaf weight (7.29; 10.34 mg cm-2) and Seed yield (1133 kg ha-1) when compared to other treatments. The present study that the application of a combined formulation of hormones and nutrients present in the nutrient consortia at the flowering and pod formation stages influenced the growth parameters and resulted in higher seed yield

Observing Pulsars with a Phased Array Feed at the Parkes Telescope

During February 2016, CSIRO Astronomy and Space Science and the Max-Planck-Institute for Radio Astronomy installed, commissioned and carried out science observations with a phased array feed (PAF) receiver system on the 64m diameter Parkes radio telescope. Here we demonstrate that the PAF can be used for pulsar observations and we highlight some unique capabilities. We demonstrate that the pulse profiles obtained using the PAF can be calibrated and that multiple pulsars can be simultaneously observed. Significantly, we find that an intrinsic polarisation leakage of -31dB can be achieved with a PAF beam offset from the centre of the field of view. We discuss the possibilities for using a PAF for future pulsar observations and for searching for fast radio bursts with the Parkes and Effelsberg telescopes.Comment: 10 pages, 8 figures, 2 tables. It has been accepted for publication in PAS

Single pulse and profile variability study of PSR J1022+1001

Millisecond pulsars (MSPs) are known as highly stable celestial clocks. Nevertheless, recent studies have revealed the unstable nature of their integrated pulse profiles, which may limit the achievable pulsar timing precision. In this paper, we present a case study on the pulse profile variability of PSR J1022+1001. We have detected approximately 14,000 sub-pulses (components of single pulses) in 35-hr long observations, mostly located at the trailing component of the integrated profile. Their flux densities and fractional polarisation suggest that they represent the bright end of the energy distribution in ordinary emission mode and are not giant pulses. The occurrence of sub-pulses from the leading and trailing components of the integrated profile is shown to be correlated. For sub-pulses from the latter, a preferred pulse width of approximately 0.25 ms has been found. Using simultaneous observations from the Effelsberg 100-m telescope and the Westerbork Synthesis Radio Telescope, we have found that the integrated profile varies on a timescale of a few tens of minutes. We show that improper polarisation calibration and diffractive scintillation cannot be the sole reason for the observed instability. In addition, we demonstrate that timing residuals generated from averages of the detected sub-pulses are dominated by phase jitter, and place an upper limit of ~700 ns for jitter noise based on continuous 1-min integrations.Comment: 13 pages, 20 figures, 3 tables, accepted for publication in MNRA

Model-based asymptotically optimal dispersion measure correction for pulsar timing

In order to reach the sensitivity required to detect gravitational waves, pulsar timing array experiments need to mitigate as much noise as possible in timing data. A dominant amount of noise is likely due to variations in the dispersion measure. To correct for such variations, we develop a statistical method inspired by the maximum likelihood estimator and optimal filtering. Our method consists of two major steps. First, the spectral index and amplitude of dispersion measure variations are measured via a time-domain spectral analysis. Second, the linear optimal filter is constructed based on the model parameters found in the first step, and is used to extract the dispersion measure variation waveforms. Compared to current existing methods, this method has better time resolution for the study of short timescale dispersion variations, and generally produces smaller errors in waveform estimations. This method can process irregularly sampled data without any interpolation because of its time-domain nature. Furthermore, it offers the possibility to interpolate or extrapolate the waveform estimation to regions where no data is available. Examples using simulated data sets are included for demonstration.Comment: 15 pages, 15 figures, submitted 15th Sept. 2013, accepted 2nd April 2014 by MNRAS. MNRAS, 201