High Resolution Observations using Adaptive Optics: Achievements and Future Needs

Over the last few years, several interesting observations were obtained with the help of solar Adaptive Optics (AO). In this paper, few observations made using the solar AO are enlightened and briefly discussed. A list of disadvantages with the current AO system are presented. With telescopes larger than 1.5m are expected during the next decade, there is a need to develop the existing AO technologies for large aperture telescopes. Some aspects of this development are highlighted. Finally, the recent AO developments in India are also presented

Resonance Line Polarization in Spherically Symmetric Moving Media: a Parametric Study

In the present paper we consider the problem of resonance line polarization formed in the spherically symmetric expanding atmospheres. For the solution of the concerned polarized transfer equation we use the comoving frame formulation, and apply the Accelerated Lambda Iteration (ALI) method. We restrict ourselves to the non-relativistic regime of velocities wherein mainly Doppler shift effects are significant. For our studies, we consider the scattering on a two-level atom, including the effects of partial frequency redistribution (PFR). We present the dependence of linearly polarized profiles on different atmospheric and atomic parameters.Comment: 10 pages, 6 figures, Proceedings of the 9th Solar Polarization Workshop SPW9, A workshop held in Gottingen, Germany, from August 26 to August 30, 201

The role of retrospective weather forecasts in developing daily forecasts of nutrient loadings over the southeast US

It is well known in the hydrometeorology literature that developing real-time daily streamflow forecasts in a given season significantly depends on the skill of daily precipitation forecasts over the watershed. Similarly, it is widely known that streamflow is the most important predictor in estimating nutrient loadings and the associated concentration. The intent of this study is to bridge these two findings so that daily nutrient loadings and the associated concentration could be predicted using daily precipitation forecasts and previously observed streamflow as surrogates of antecedent land surface conditions. By selecting 18 relatively undeveloped basins in the southeast US (SEUS), we evaluate the skill in predicting observed total nitrogen (TN) loadings in the Water Quality Network (WQN) by first developing the daily streamflow forecasts using the retrospective weather forecasts based on K-nearest neighbor (K-NN) resampling approach and then forcing the forecasted streamflow with a nutrient load estimation (LOADEST) model to obtain daily TN forecasts. Skill in developing forecasts of streamflow, TN loadings and the associated concentration were computed using rank correlation and RMSE (root mean square error), by comparing the respective forecast values with the WQN observations for the selected 18 Hydro-Climatic Data Network (HCDN) stations. The forecasted daily streamflow and TN loadings and their concentration have statistically significant skill in predicting the respective daily observations in the WQN database at all 18 stations over the SEUS. Only two stations showed statistically insignificant relationships in predicting the observed nitrogen concentration. We also found that the skill in predicting the observed TN loadings increases with the increase in drainage area, which indicates that the large-scale precipitation reforecasts correlate better with precipitation and streamflow over large watersheds. To overcome the limited samplings of TN in the WQN data, we extended the analyses by developing retrospective daily streamflow forecasts over the period 1979–2012 using reforecasts based on the K-NN resampling approach. Based on the coefficient of determination (R2Q-daily) of the daily streamflow forecasts, we computed the potential skill (R2TN-daily) in developing daily nutrient forecasts based on the R2 of the LOADEST model for each station. The analyses showed that the forecasting skills of TN loadings are relatively better in the winter and spring months, while skills are inferior during summer months. Despite these limitations, there is potential in utilizing the daily streamflow forecasts derived from real-time weather forecasts for developing daily nutrient forecasts, which could be employed for various adaptive nutrient management strategies for ensuring better water quality

Characterization of horizontal flows around solar pores from high-resolution time series of images

Though there is increasing evidence linking the moat flow and the Evershed flow along the penumbral filaments, there is not a clear consensus regarding the existence of a moat flow around umbral cores and pores, and the debate is still open. Solar pores appear to be a suitable scenario to test the moat-penumbra relation as evidencing the direct interaction between the umbra and the convective plasma in the surrounding photosphere, without any intermediate structure in between. The present work studies solar pores based on high resolution ground-based and satellite observations. Local correlation tracking techniques have been applied to different-duration time series to analyze the horizontal flows around several solar pores. Our results establish that the flows calculated from different solar pore observations are coherent among each other and show the determinant and overall influence of exploding events in the granulation around the pores. We do not find any sign of moat-like flows surrounding solar pores but a clearly defined region of inflows surrounding them. The connection between moat flows and flows associated to penumbral filaments is hereby reinforced by this work.Comment: 10 pages, 10 figures, Accepted for publication in Astronomy and Astrophysics

How Does Flow Alteration Propagate Across a Large, Highly Regulated Basin? Dam Attributes, Network Context, and Implications for Biodiversity

Large dams are a leading cause of river ecosystem degradation. Although dams have cumulative effects as water flows downstream in a river network, most flow alteration research has focused on local impacts of single dams. Here we examined the highly regulated Colorado River Basin (CRB) to understand how flow alteration propagates in river networks, as influenced by the location and characteristics of dams as well as the structure of the river network—including the presence of tributaries. We used a spatial Markov network model informed by 117 upstream-downstream pairs of monthly flow series (2003–2017) to estimate flow alteration from 84 intermediate-to-large dams representing \u3e83% of the total storage in the CRB. Using Least Absolute Shrinkage and Selection Operator regression, we then investigated how flow alteration was influenced by local dam properties (e.g., purpose, storage capacity) and network-level attributes (e.g., position, upstream cumulative storage). Flow alteration was highly variable across the network, but tended to accumulate downstream and remained high in the main stem. Dam impacts were explained by network-level attributes (63%) more than by local dam properties (37%), underscoring the need to consider network context when assessing dam impacts. High-impact dams were often located in sub-watersheds with high levels of native fish biodiversity, fish imperilment, or species requiring seasonal flows that are no longer present. These three biodiversity dimensions, as well as the amount of dam-free downstream habitat, indicate potential to restore river ecosystems via controlled flow releases. Our methods are transferrable and could guide screening for dam reoperation in other highly regulated basins

Converging and diverging convection around axisymmetric magnetic flux tubes

A numerical model of idealized sunspots and pores is presented, where axisymmetric cylindrical domains are used with aspect ratios (radius versus depth) up to 4. The model contains a compressible plasma with density and temperature gradients simulating the upper layer of the Sun's convection zone. Non-linear magnetohydrodynamic equations are solved numerically and time-dependent solutions are obtained where the magnetic field is pushed to the centre of the domain by convection cells. This central magnetic flux bundle is maintained by an inner convection cell, situated next to it and with a flow such that there is an inflow at the top of the numerical domain towards the flux bundle. For aspect ratio 4, a large inner cell persists in time, but for lower aspect ratios it becomes highly time dependent. For aspect ratios 2 and 3 this inner convection cell is smaller, tends to be situated towards the top of the domain next to the flux bundle, and appears and disappears with time. When it is gone, the neighbouring cell (with an opposite sense of rotation, i.e. outflow at the top) pulls the magnetic field away from the central axis. As this happens a new inner cell forms with an inflow which pushes the magnetic field towards the centre. This suggests that to maintain their form, both pores and sunspots need a neighbouring convection cell with inflow at the top towards the magnetic flux bundle. This convection cell does not have to be at the top of the convection zone and could be underneath the penumbral structure around sunspots. For an aspect ratio of 1, there is not enough space in the numerical domain for magnetic flux and convection to separate. In this case the solution oscillates between two steady states: two dominant convection cells threaded by magnetic field and one dominant cell that pushes magnetic flux towards the central axis

Users opinion about synthetic, bio- and nano-biopesticides

As authors, we would like to convey our sincere thanks to Department of Chemistry, Govt. V.Y.T. PG. Autonomous College, Durg, for their valuable technical support given in this project. We would like to express our earnest thanks Dr. Poonrathi (Chief Medical Officer in charge - Kodai Govt. Hospital), Dr. Tamilselvan (Junior doctor- Krishnagiri Govt. Medical Health Unit), Ms. N.V. Ratana (Department of Agriculture – Telangana), Dr. Thirupurasundari (Dietician – USA), Ms. Tan (Organic Activist – KL), and Ms. Krithika Lakshmi (HR – Advisor, KL) for their valuable comments, timely advice, and suggestions. We also would like to thank all participants for devoting their precious time by helping us in this survey. We would like to share our humble gratitude to Dr. R. Senthil Kumar, Assistant Professor, Department of Statistics, Madras Christian College (Autonomous), Chennai, for his timely help and advice for statistical evaluation. SACC is grateful to Fundaç ão para a Ciência e a Tecnologia (FCT), Portugal for Scientific Employment Stimulus-Institutional Call (CEEC-INST/00102/2018) and to the Associate Laboratory for Green Chemistry - LAQV financed by national funds from FCT/MCTES (UIDP/5006/2020). The study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Review Board (or Ethics Committee) of Govt. V. Y. T. PG Autonomous College, Durg (protocol code IEC/GVYTPGACI 19 /DURG. Date- 30/10/2021) for studies involving humans. Informed consent was obtained from all subjects involved in the study. Publisher Copyright: © 2023 The AuthorsWith a growing global population, the demand for food, clothing and shelter became crucial for sustaining life. Moreover, the COVID-19 pandemic/endemic, along with the threat of other endemics, posed significant challenges in ensuring the delivery of nutritionally rich food. To address this, the World Health Organization (WHO) recommended the ban of some highly toxic chemical pesticides. Excessive consumption and exposure to pesticides possibly contributed to a decline in the human immunity levels making our fight against the pandemics more difficult and challenging. During the lockdown COVID-19 crisis, we conducted a survey to gather insights from farm landers (FLs), garden lovers (GLs), domestic front users (DFUs) predominantly from India, but also from other regions worldwide. The survey aimed at better understanding the usage of pesticides, both chemicals (CPs), bio-pesticides (BPs) or both, and their global utilization. A statistical survey with seven rudimentary sections was designed to receive the inputs (elementary inputs, awareness and perception, pesticide utility, health, ecology, and alternatives for safer trials) with fairness and care. The data was statistically analyzed within each group of population, revealing significant variations within the groups. Our study indicated that FLs (44.7 %) predominantly used BPs, GLs (18.8 %) relied on CPs, while DFUs (100.0 %) used a combination of both without any specific intention. Correlation analysis, given by R (correlation coefficient) and p (probability of obtaining an equal or more extreme effect than the found considering the null hypothesis as true) values revealed the existence of a positive and significant relationship between the selected variables, such as level of education (LOE) and gender, with the adoption of new alternatives (2loglikelihood = 64.743, with χ2 = 128.4, degrees of freedom (df) = 24, p<*0.05, **0.01, and *** 0.001) through multinomial regression analysis, indicating the fitness of the model. Likewise, our study primarily focused on exploring the insights for the development of nano-biopesticides, as improved alternatives to the existing solutions.publishersversionpublishe

Characterizing Spectral Channels of Visible Emission Line Coronagraph of Aditya-L1

Aditya-L1 is India’s first solar mission with the Visible Emission Line Coronagraph (VELC), which consists of three spectral channels taking high-resolution spectroscopic observations of the inner corona up to 1.5 Rʘ at 5,303, 7,892, and 10,747 Å. In this work, we present a strategy for the slit width optimization of the VELC using synthetic line profiles by taking into account the instrument characteristics and coronal conditions for log(T) varying from 6 to 6.5. The synthetic profiles are convolved with simulated instrumental scattered light and noise to estimate the signal-to-noise ratio (SNR), which will be crucial to designing the future observation plans. We find that the optimum slit width for VELC turns out to be 50 μm, providing sufficient SNR for observations in different solar conditions. We also analyzed the effect of plasma temperature on the SNR at different heights in the VELC field of view for the optimized slit width. We also studied the expected effect of the presence of a CME on the spectral channel observations. This analysis will help to plan the scientific observations of VELC in different solar conditions