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This work presents a quad-port Multiple Input Multiple Output (MIMO) wideband antenna that operates in the terahertz (THz) frequency range is designed and analyzed. To improve MIMO performance, a defective ground structure (DGS) is used. A rectangular metallic patch was altered by adding parasitic elements to the radiator with the lowered ground plane on a polyamide substrate in order to achieve the wideband THz operating frequency. The THz antenna was turned into a MIMO antenna by replicating horizontally and vertically with a spacing of 0.05 λ and 0.002 λ, respectively (λ calculated at 1.7 THz). The designed THz MIMO antenna, comprising 40 μm × 46 μm × 2 μm, operates across the 1.7–10.4 THz frequency region. The THz MIMO antenna provides isolation of more than 20 dB in the frequency range of 2.8–10.4 THz and more than 10 dB for the frequency of 1.7–2.7 THz. Isolation augmentation is accomplished by establishing different local current channels using the antenna's DGS. The MIMO diversity properties of the proposed THz MIMO antenna are analyzed and found to be ECC

We selected three superstorms (disturbance storm time [Dst] index less than −350 nT) of 2003–04 to study the thermospheric energy budget with a particular emphasis on the thermospheric cooling emission by nitric oxide via a wavelength of 5.3 μm. The nitric oxide radiative emission data are obtained from the Sounding of the Atmosphere by Broadband Emission Radiometry (SABER) instrument onboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite and the thermosphere ionosphere electrodynamic general circulation model (TIEGCM) simulation. Different energy sources for the magnetospheric energy injection and the thermospheric/ionospheric dissipation processes are calculated using empirical formulations, model simulations, and space-borne and ground-based measurements. The Joule heating rates calculated from different sources showed similar variations but significant differences in the magnitude. The nitric oxide cooling power is calculated by zonally and meridionally integrating the cooling flux in the altitude range of 100–250 km. The satellite observed that cooling flux responds faster to the energy input, as compared to the modeled results. The cooling power increases by an order of magnitude during storm time with maximum radiation observed during the recovery phase. Both the satellite-observed and modeled cooling powers show a strong positive correlation with the Joule heating power during the main phase of the storm. It is found that the maximum radiative power does not occur during the strongest storm, and it strongly depends on the duration of the main phase. The model simulation predicts a higher cooling power than that predicted by the observation. During a typical superstorm, on average, a cooling power of 1.87 × 105 GW exiting the thermosphere is estimated by the TIEGCM simulation. On average, it is about 40% higher than the satellite observation.

Software fault prediction is a critical aspect of software engineering aimed at improving software quality and reliability. However, it faces significant challenges, including the class imbalance issue in fault data and the need for robust predictive models that generalize well across different projects. In this research, we delve into these challenges and investigate the impact of class imbalance and model generalization on software fault prediction using cross-project analysis. Our study addresses three primary research questions: Firstly, we examine the critical issue of class imbalance in fault prediction, which poses a significant hurdle to accurate model performance. Through extensive experimentation with various classifiers on diverse datasets from different software projects, we highlight the variations in classifier performance and the necessity of addressing class imbalance for reliable predictions. Secondly, we evaluate the reliability of cross-project prediction, aiming to understand how effectively predictive models trained on one project can generalize to predict faults in other projects. We demonstrate the importance of training with datasets sharing similar characteristics with the target project for achieving reliable cross-project prediction. Thirdly, we analyze the impact of increasing training samples from different projects on prediction accuracy, emphasizing the benefits of utilizing cross-project analysis to enhance predictive model performance. In addition to addressing these research questions, we provide a comprehensive comparison of classifier performance metrics, including accuracy, precision, recall, and F1 Score. Our findings not only shed light on the challenges and opportunities in software fault prediction but also emphasize the importance of considering class imbalance and model generalization for developing robust and reliable fault prediction models. This research contributes to advancing the field by providing insights into effective modeling approaches and highlighting the motivation behind addressing these challenges.

Background: Lumbosacral transitional vertebrae are common congenital anomaly of the spine involving the lumbosacral vertebral junction with a prevalence of 4% - 35.9%. It can present as sacralization of the lowermost lumbar vertebra or lumbarization of the first sacral vertebra with varying degree of transition from partial to complete fusion. Non-recognition of this variant and/or poor description in the report can lead to operations or procedures performed at the wrong level. Aims and objectives: The purpose of this descriptive cross-sectional study is to determine the prevalence and frequency of different types of Lumbosacral transitional vertebra (LSTV) in patients with low back pain in South Indian population. Materials and methods: Plain radiographs of the lumbosacral spine of 450 patients who presented with lower back pain were retrospectively reviewed for the presence and type of LSTV. Results: Using Castellvi system, 450 patients were evaluated and LSTV was observed in 126 patients (28%). Among them 51 (40%) patients had type I, 42 (33.3%) had type II, 27 (21.4%) had type III and 6 (4.7%) had type IV. Conclusion: LSTV occurs at a high frequency in patients with LBP in South Indian population.

The present investigation was carried out at the ICAR-AICRP Palms centre, Coconut Research Station, TNAU, Aliyarnagar, Tamil Nadu during 2012 to 2020 with five location specific coconut hybrids along with two tall varieties as local adopted checks viz., West Coast Tall (WCT) and Kalpatharu. Correlation and path analysis was performed to assess the association among nut yield and copra yield with important yield contributing traits in Coconut (Cocos nucifera L.). Correlation and path analysis revealed that copra yield per palm was positively and significantly associated with the fruit component traits viz., nut yield per palm per year, de-husked nut weight, whole nut weight, copra weight, fruit breadth and fruit length. A positive correlation was found among fruit component traits viz,, fruit length, fruit breadth, whole nut weight, de-husked nut weight and copra weight. Path coefficient analysis showed that nut yield, de-husked nut weight, and copra weight recorded the highest positive direct effect on copra yield per palm. The results of the present study suggest that selection for high copra yield based on the total number of nuts per palm per year, copra weight per nut and de-husked nut weight in coconut would be rewarding for developing high yielding genotypes in coconut.

Genetic variability, heritability and genetic advance analysis of growth, floral, yield and yield attributing traits were studied in four dwarf x tall coconut hybrids, one tall x dwarf hybrid along with two tall varieties as checks. The palms were raised in four replications in randomised block design with six palms per replication. The age of the palm was nine years. Observations on morphological features were recorded in all the palms and the datas were subjected to statistical analysis. It revealed high to moderate degree of variability among the genotypes for most of the traits studied. The genetic variability studies indicated that the number of nuts per palm, whole nut weight, de-husked nut weight and tender nut water content evidenced high degree for phenotypic coefficient of variation and genotypic coefficient of variation. Superior level of heritability was recorded for palm height, leaflet breadth, the number of leaves, nut yield, fruit length, fruit breadth, tender nut water content, whole nut weight, de-husked nut weight and copra outturn thus indicating the prominence of genetic influence in inheritance of these traits. Genetic advance expressed on per cent mean was high in palm height, nut yield, tender nut water content, whole nut weight, de-husked nut weight and copra outturn. Therefore, the above traits could be given due weightage in coconut breeding programmes.

This study investigates the influence of the 2015 Calbuco eruption (41.2∘ S, 72.4∘ W; Chile) on the total columnar aerosol optical properties over the Southern Hemisphere. The well-known technic of sun photometry was applied for the investigation of the transport and spatio-temporal evolution of the optical properties of the volcanic plume. The CIMEL sun photometer measurements performed at six South American and three African sites were statistically analysed. This study involves the use of the satellite observations and a back-trajectory model. The passage of the Calbuco plume is statistically detectable in the aerosol optical depth (AOD) observations obtained from sun photometer and MODIS observations. This statistical detection confirms that the majority of the plume was transported over the northeastern parts of South America and reached the South African region 1 week after the eruption. The plume impacted the southern parts of South America to a lesser extent. The highest AOD anomalies were observed over the northeastern parts of South America. Over the South African sites, the AOD anomalies induced by the spread of the plume were quite homogeneously distributed between the east and west coasts. The optical characteristics of the plume near the source region were consistent with an ash-bearing plume. Conversely, sites further from the Calbuco volcano were influenced by ash-free plume. The optical properties discussed in this paper will be used as inputs for numerical models for further investigation of the ageing of the Calbuco plume in a forthcoming study.

Introduction: High prevalence of chronic kidney disease (CKD) not associated with known risk factors has been reported from coastal districts of Andhra Pradesh. The Study to Test and Operationalize Preventive Approaches for Chronic Kidney Disease of Undetermined Etiology in Andhra Pradesh (STOP CKDu AP) aims to ascertain the burden (prevalence and incidence) of CKD, the risk factor profile, and the community perceptions about the disease in the Uddanam area of Andhra Pradesh. Methods: Study participants will be sampled from the Uddanam area using multistage cluster random sampling. Information will be collected on the demographic profile, occupational history, and presence of conventional as well as nonconventional risk factors. Glomerular filtration rate (GFR) will be estimated using the Chronic Kidney Disease Epidemiology Collaboration equation, and proteinuria will be measured. All abnormal values will be confirmed by repeat testing after 3 months. Cases of CKD not associated with identified etiologies will be identified. Biospecimens will be stored to explore future hypotheses. The entire cohort will be followed up every 6 months to determine the incidence of CKD and to identify risk factors for decline in kidney function. Qualitative studies will be performed to understand the community perceptions and expectations with respect to the interventions. Implications: CKD is an important public health challenge in low- and middle-income countries. This study will establish the prevalence and determine the incidence of CKD not associated with known risk factors in a reported high-burden region, and will provide insights to help design targeted health systems responses. The findings will contribute to the policy development to tackle CKD in the region and will permit international comparisons with other regions with similar high prevalence. Keywords: chronic kidney disease, CKD of uncertain etiology, risk factors

An experiment to evaluate the coconut hybrids for tender nut was conducted at Coconut Research Station, Aliyar nagar during 2017-18. Seven cross combinations along with eight parents were studied. The heterosis for number of female flowers/palm/year, number of bunches/palm, number of tender nuts/bunch/palm and total number of tender nuts/palm/year of coconut were assessed. All coconut hybrids showed a well pronounced heterotic expression which could be exploited. It is concluded from the present study that all the cross combinations performed better than the parents for all the four economically important traits. The coconut hybrids showing well pronounced heterotic expression could be exploited for development of location specific hybrids of commercial importance.

Long-term variability in ozone trends was assessed over eight Southern Hemisphere tropical and subtropical sites (Natal, Nairobi, Ascension Island, Java, Samoa, Fiji, Reunion and Irene), using total column ozone data (TCO) and vertical ozone profiles (altitude range 15–30 km) recorded during the period January 1998–December 2012. The TCO datasets were constructed by combination of satellite data (OMI and TOMS) and ground-based observations recorded using Dobson and SAOZ spectrometers. Vertical ozone profiles were obtained from balloon-sonde experiments which were operated within the framework of the SHADOZ network. The analysis in this study was performed using the Trend-Run model. This is a multivariate regression model based on the principle of separating the variations of ozone time series into a sum of several forcings (annual and semi-annual oscillations, QBO (Quasi-Biennial Oscillation), ENSO, 11-year solar cycle) that account for most of its variability. The trend value is calculated based on the slope of a normalized linear function which is one of the forcing parameters included in the model. Three regions were defined as follows: equatorial (0–10° S), tropical (10–20° S) and subtropical (20–30° S). Results obtained indicate that ozone variability is dominated by seasonal and quasi-biennial oscillations. The ENSO contribution is observed to be significant in the tropical lower stratosphere and especially over the Pacific sites (Samoa and Java). The annual cycle of ozone is observed to be the most dominant mode of variability for all the sites and presents a meridional signature with a maximum over the subtropics, while semi-annual and quasi-biannual ozone modes are more apparent over the equatorial region, and their magnitude decreases southward. The ozone variation mode linked to the QBO signal is observed between altitudes of 20 and 28 km. Over the equatorial zone there is a strong signal at ∼ 26 km, where 58 % ±2 % of total ozone variability is explained by the effect of QBO. Annual ozone oscillations are more apparent at two different altitude ranges (below 24 km and in the 27–30 km altitude band) over the tropical and subtropical regions, while the semi-annual oscillations are more significant over the 27–30 km altitude range in the tropical and equatorial regions. The estimated trend in TCO is positive and not significant and corresponds to a variation of ∼ 1.34±0.50 % decade−1 (averaged over the three regions). The trend estimated within the equatorial region (0–15° S) is less than 1 % per decade, while it is assessed at more than 1.5 % decade−1 for all the sites located southward of 17° S. With regard to the vertical distribution of trend estimates, a positive trend in ozone concentration is obtained in the 22–30 km altitude range, while a delay in ozone improvement is apparent in the UT–LS (upper troposphere–lower stratosphere) below 22 km. This is especially noticeable at approximately 19 km, where a negative value is observed in the tropical regions.

In this investigation a statistical analysis of the characteristics of mesospheric inversion layers (MILs) over tropical regions is presented. This study involves the analysis of 16 years of lidar observations recorded at Réunion (20.8° S, 55.5° E) and 21 years of lidar observations recorded at Mauna Loa (19.5° N, 155.6° W) together with SABER observations at these two locations. MILs appear in 10 and 9.3 % of the observed temperature profiles recorded by Rayleigh lidar at Réunion and Mauna Loa, respectively. The parameters defining MILs show a semi-annual cycle over the two selected sites with maxima occurring near the equinoxes and minima occurring during the solstices. Over both sites, the maximum mean amplitude is observed in April and October, and this corresponds to a value greater than 35 K. According to lidar observations, the maximum and minimum mean of the base height ranged from 79 to 80.5 km and from 76 to 77.5 km, respectively. The MILs at Réunion appear on average ∼ 1 km thinner and ∼ 1 km lower, with an amplitude of ∼ 2 K higher than Mauna Loa. Generally, the statistical results for these two tropical locations as presented in this investigation are in fairly good agreement with previous studies. When compared to lidar measurements, on average SABER observations show MILs with greater amplitude, thickness and base altitudes of 4 K, 0.75 and 1.1 km, respectively. Taking into account the temperature error by SABER in the mesosphere, it can therefore be concluded that the measurements obtained from lidar and SABER observations are in significant agreement. The frequency spectrum analysis based on the lidar profiles and the 60-day averaged profile from SABER confirms the presence of the semi-annual oscillation where the magnitude maximum is found to coincide with the height range of the temperature inversion zone. This connection between increases in the semi-annual component close to the inversion zone is in agreement with most previously reported studies over tropics based on satellite observations. Results presented in this study confirm through the use of the ground-based Rayleigh lidar at Réunion and Mauna Loa that the semi-annual oscillation contributes to the formation of MILs over the tropical region.

In this study an attempt was made to investigate the efficiency of spray drying process of pomegranate juice using response surface methodology (RSM). Different drying conditions such as inlet air temperature (A), feed flow rate (B) and aspirator rate (C) were varied in order to study the changes in quality parameters of spray drying process including moisture content (Y1), hygroscopicity (Y2), powder yield (Y3). Three factors three level Box–Behnken response surface design (BBD) was used to evaluate the effect of process variables on spray drying process. 3D Response surface contour plots were used to study the interactive effects of the process conditions and optimal spray drying conditions were determined as follows: inlet air temperature of 130 °C, feed flow rate of 6 rpm and aspirator rate of 100%. Under these conditions, moisture content, hygroscopicity and powder yield are found to be 6.85%, 19.85 g/100 g and 14.95 g respectively.

Aerodynamic performance of a two-element camber morphing airfoil was investigated at low Reynolds number using the transient SST model in ANSYS FLUENT 14.0 and eN method in XFLR5. The two-element camber morphing concept was employed to morph the baseline airfoil into another airfoil by altering the orientation of mean-line at 35% of the chord to achieve better aerodynamic efficiency. NACA 0012 was selected as baseline airfoil. NACA 23012 was chosen as the test case as it has the camber-line similar to that of the morphed airfoil and as it has the same thickness as that of the baseline airfoil. The simulations were carried out at chord based Reynolds numbers of 2.5×105 and 3.9×105. The aerodynamic force coefficients, aerodynamic efficiency and the location of the transition point of laminar separation bubble over these airfoils were studied for various angles of attack. It was found that the aerodynamic efficiency of the morphed airfoil was 12% higher than that of the target airfoil at 4° angle of attack for Reynolds number of 3.9×105 and 54% rise in aerodynamic performance was noted as Reynolds number was varied from 2.5×105 to 3.9×105. The morphed airfoil exhibited the nature of low Reynolds number airfoil.

Abstract Background Mn-Zn ferrites have drawn a continuously an increasing interest because of their potential applications as multifunctional devices. These materials simultaneously exhibit ferroelectricity and ferromagnetism. The dielectric and leakage current properties of Cobalt substituted Mn-Zn ferrites coated with oleic acid were not reported . Methods This paper presents the synthesis, electrical, and leakage properties of nanoparticles of cobalt-doped Mn-Zn ferrite [Co xMnyZnyFe2O4 (x = 0.1, 0.5, and 0.9 and y = 0.45, 0.25, and 0.05)] coated with oleic acid and prepared by chemical co-precipitation method. The crystal structure was determined by X-ray diffraction (XRD), the effect of strain on the electronic structure was analyzed using Williamson-Hall plot. Complex impedance spectroscopic analysis was carried out, and the impedance plots show the resistive and reactive parts of the impedance. Frequency dependence on AC conductivity was investigated for all the compositions, and leakage current properties were also studied. Results The nanoparticles were found to have an average size of 13.62 nm. The average crystallite size ( DaveXR ) of the precipitated particles found to decrease from 15.22 to 12.65 nm with increasing cobalt substitution. The presence of two semicircular arcs at the lower and higher frequency regions indicates the grain boundary conduction and grain conduction at room temperature . Leakage current density of the order of 10-4 A/cm2 (at field strength of 0.02 kV/cm) was observed for all compositions . Conclusion The variation of the strain values from negative to positive indicates that the strain changes from compression to tensile. The dielectric permittivity was found to decrease from 104to 103 with increase in frequency. The semicircle in the higher frequency region is attributed to the grain conduction of the materials, and the semicircle in the lower frequency region is due to the grain boundary conduction. Both the grain and grain boundary are found to be active at room temperature. A C conductivity is found to be compositional dependent.

The aim of this research was to optimize the operating parameters in microwave assisted extraction process (MIE) such as temperature, mass of the sample, extraction time on the betalain content from dragon fruit peel using response surface methodology (RSM). Three factors three levels Box-Behnken response surface design (BBD) was used for optimization and mathematical model development. Significant quadratic polynomial model was obtained (R2 = 0.9892 for betalain content) with high coefficient determination value and numerical optimization was employed to achieve optimum conditions which was found to be; temperature of 35 °C, mass of the sample of 20 g, and treatment time of 8 min. Under these conditions, 9 mg/L of betalain content was obtained and it was validated using experimental values.

The correlation studies in thirty four genotypes of brinjal comprising ten parents, twenty one F1 hybrids and three checks during summer season of 2014 indicated strong positive correlation of primary branches per plant, days to final harvest, flowers per cluster, fruits per cluster, fruit length, average fruit weight and fruits per plant with fruit yield per. However, a significant negative correlation of fruit yield per plant was observed with days to 50% flowering. The path analysis study revealed that the fruits length is the most important yield determinant, because of its high direct effect and indirectly influence the yield through primary branches per plant, days to final harvest, fruits per cluster, average fruit weight and fruits per plant followed by fruits per plant is the another most important yield determinant thus, these characters should be given importance in selection programme for yield improvement in brinjal.

Ascidians are well known worldwide for their rapid invasions and also for the presence of potential biomedical molecules. Members of the family Didemnidae are widely distributed in tropical waters and they are reported to be among the families possessing rich bioactive compounds. Didemnum psammathodes has a cosmopolitan distribution in tropical waters. The growing evidence of multifarious potential and ever increasing invasion of this species accentuated the need for additional research into its diversity and distribution for sustainable utilization and conservation. The present study was intended to focus on distribution and invasiveness of colonial ascidian, D. psammathodes, along the southern Indian peninsular waters. The present data are based on our own observations made during 2012–2014 period and also on the published and unpublished records of the last 20 years. Out of 45 stations surveyed, D. psammathodes was encountered at a maximum of 41 stations and was found to be more abundant in Hare Island (n = 42), North Break Water (n = 38) and Vizhinjam bay (n = 32). This species was absent at four different stations. Catch per unit effort was higher (19.6) in Hare Island followed by NBW (16.0) and Vizhinjam bay (6.8). The highest number of colonies (136) was observed in calcareous stones, followed by embedded rocks (54) and molluscan shells (33). Hydrographical parameters showed no significant differences between the stations (p

A vacuum drying process was employed to deal with the moisture removal, Vitamin C content and total dietary fiber from coriander leaves (dhania). Box–Behnken design (BBD) and response surface methodology (RSM) were applied to evaluate and optimize the three key drying parameters, namely temperature (A), loading rate (B) and vacuum (C). This approach provided statistically significant quadratic model, which was adequate to predict response and to carry out optimization under the conditions studied. It was demonstrated that the interaction between all the drying parameters has a significant effect on the moisture removal. The optimal conditions were found to be temperature of 75 °C, loading rate of 0.63 kg/m2 and vacuum = 28 mm Hg. Under these conditions, 95% moisture removal, 527 mg/100 g Vitamin C content and 13 g/100 g total dietary fiber were obtained. Finally, product quality was also examined.

Underwater Acoustic Sensor Networks (UWASNs) play an important role in monitoring the aqueous environment which has created a lot of interest for researchers and scientists. Utilization of underwater acoustic sensor node (UASN) scheduling for transmission remains, due to the limited acoustic bandwidth available, a challenge in such an environment. One of the methods to overcome this problem is to efficiently schedule UASN data using time division multiple access (TDMA) protocols the parallel transmissions, simultaneously avoiding interference. The paper shows how to optimize the utilization of acoustic sensor node bandwidth by maximizing the possible node transmissions in the TDMA frame and also by minimizing the node’s turnaround wait time for its subsequent transmissions by using an evolutionary memetic algorithm (MA). The simulation of MA-TDMA proves that as the size of the network increases, every node in UWASN transmits with an average minimal turnaround transmission time. It also proves that as the TDMA cycle repeats, the overall network throughput gets maximized by increasing the possible node transmissions in the MA-TDMA frame.

This paper presents comparison results of the total column ozone (TCO) data product over 13 southern tropical and subtropical sites recorded from the Infrared Atmospheric Sounder Interferometer (IASI) onboard the EUMETSAT (European organization for the exploitation of METeorological SATellite) MetOp (Meteorological Operational satellite program) satellite. TCO monthly averages obtained from IASI between June 2008 and December 2012 are compared with collocated TCO measurements from the Ozone Monitoring Instrument (OMI) on the OMI/Aura satellite and the Dobson and SAOZ (Système d'Analyse par Observation Zénithale) ground-based instruments. The results show that IASI displays a positive bias with an average less than 2 % with respect to OMI and Dobson observations, but exhibits a negative bias compared to SAOZ over Bauru with a bias around 2.63 %. There is a good agreement between IASI and the other instruments, especially from 15° S southward where a correlation coefficient higher than 0.87 is found. IASI exhibits a seasonal dependence, with an upward trend in autumn and a downward trend during spring, especially before September 2010. After September 2010, the autumn seasonal bias is considerably reduced due to changes made to the retrieval algorithm of the IASI level 2 (L2) product. The L2 product released after August (L2 O3 version 5 (v5)) matches TCO from the other instruments better compared to version 4 (v4), which was released between June 2008 and August 2010. IASI bias error recorded from September 2010 is estimated to be at 1.5 % with respect to OMI and less than ±1 % with respect to the other ground-based instruments. Thus, the improvement made by O3 L2 version 5 (v5) product compared with version 4 (v4), allows IASI TCO products to be used with confidence to study the distribution and interannual variability of total ozone in the southern tropics and subtropics.

The quality of education is determined by the quality of the teachers. As teachers are entrusted with the responsibility of shaping and guiding the future citizens of a nation, it is essential for them to be involved and committed toward their job. This brings out the importance of retaining teachers in their job. The concept of workplace spirituality (WPS) brings in the very feeling of being connected to the workplace, which, undoubtedly helps them to remain attached to the job. The study tries to understand the relationship between WPS and job embeddedness (JE) among the higher secondary school teachers in Ernakulam District. WPS was measured using the scale adapted from Milliman et al. and JE was measured using the scale developed by Mitchell et al. A sample size of 105 was selected using simple random sampling method. The study found a satisfactorily good level of WPS and JE among the respondents. The result of the study also shows a significant positive relationship between WPS and JE.

Long-term data available from Lidar systems located at three different locations namely São José dos Campos, Brazil (23.2° S, 45.8° W), Gadanki (13.5° N, 79.2° E) and Reunion (20.8° S, 55.5° E) have been used to investigate the long-term variations like Annual, Semi-annual, Quasi-biennial, El Nino Southern Oscillation and solar cycle. These oscillations are also extracted from simultaneous satellite borne measurements of HALogen Occultation Experiment (HALOE) instrument onboard UARS and SABER onboard TIMED over these stations making largest time series covering the entire middle atmosphere. A good agreement is found between the LIDAR and satellite-derived amplitudes and phases between 30 and 65 km altitude, which suggests that satellite measurements can be used to investigate the long-term trends globally. Latter measurements are extended to 80 km in order to further investigate these oscillations. Large difference in the amplitudes between the eastern pacific and western pacific is noticed in these oscillations. Changing from cooling trends in the stratosphere to warming trends in the mesosphere occurs more or less at altitude around 70 km altitude and this result agrees well with that observed by satellite measurements reported in the literature. The peak in the cooling trend does not occur at a fixed altitude in the stratosphere however maximum warming trend is observed around 75 km at all the stations. The observed long-term trends including various oscillations are compared with that reported with various techniques.

Using absorption data measured by imaging riometer for ionospheric studies (IRIS) located at the South Africa National Antarctic Expedition (SANAE), Antarctica (72° S, 3° W), we extracted the parameters of gravity waves (GW) of periods between 40 and 50 min during late winter/spring of the year 2002, a period of the unprecedented major sudden stratospheric warming (SSW) in the Southern Hemisphere middle atmosphere. During this period, an unprecedented substantial increase of temperature by about 25–30 K throughout the stratosphere was observed. During the period of the occurrence of the major stratospheric warming, there was a reduction of both the GW horizontal phase speeds and the horizontal wavelengths at 90 km. The GW phase speeds and horizontal wavelengths were observed to reach minimum values of about 7 m s−1 and 19 km, respectively, while during the quiet period the average value of the phase speed and horizontal wavelength was approximately 23 m s−1 and 62 km, respectively. The observed event is discussed in terms of momentum flux and also a potential interaction of gravity waves, planetary waves and mean circulation.

In this study, a comparative approach was made between artificial neural network (ANN) and response surface methodology (RSM) to predict the mass transfer parameters of osmotic dehydration of papaya. The effects of process variables such as temperature, osmotic solution concentration and agitation speed on water loss, weight reduction, and solid gain during osmotic dehydration were investigated using a three-level three-factor Box-Behnken experimental design. Same design was utilized to train a feed-forward multilayered perceptron (MLP) ANN with back-propagation algorithm. The predictive capabilities of the two methodologies were compared in terms of root mean square error (RMSE), mean absolute error (MAE), standard error of prediction (SEP), model predictive error (MPE), chi square statistic (χ2), and coefficient of determination (R2) based on the validation data set. The results showed that properly trained ANN model is found to be more accurate in prediction as compared to RSM model.

For the first time, climatology of the middle atmosphere thermal structure is presented, based on 14 years of LIDAR and satellite (HALOE, SABER, CHAMP and COSMIC) temperature measurements. The data is collected over a southern sub-tropical site, Reunion Island (20.8° S; 55.5° E), for the height range between 30 and 60 km. The overall monthly mean temperature shows a maximum of 265–270 K at the stratopause height region from ~44–52 km and peaks during the months of March and November. Furthermore, the temperature profiles are compared with different satellite datasets (HALOE, CHAMP, COSMIC and SABER) and the results are found to be in reasonable agreement with each other, although a relative difference in temperature of ± 5 to 6 K is noticed. In comparison, LIDAR shows higher/lower temperatures for the lower mesosphere/upper stratosphere height region. The differences in temperature measured by the LIDAR and satellite measurements are analogous with previous results available elsewhere. Long-term temperature measurements are used to further study seasonal oscillations, especially annual, semi-annual and quasi-biennial oscillations. In comparison with SAO, the measured spectral amplitudes of AO shows dominant amplitudes in both the upper stratosphere and lower mesosphere height regions. Using LIDAR and the other satellite measurements, the quasi-biennial oscillation was found to be approximately 26 months. The spectral amplitudes are comparable to the results reported earlier by other researchers.

This paper mainly focuses on the trends and variability of the UT-LS temperature using radiosonde observations carried out over 16 years (January 1993 to December 2008) from a southern subtropical site, Reunion (20.8° S, 55.5° E), using a linear-regression fitting model. Two kinds of tropopause definitions, namely, cold point tropopause (CPT) and lapse rate tropopause (LRT) are used. In order to characterize and quantify the relationship between regional oceanic forcing and temperature at UT-LS, we took into account the Indian Ocean Dipole (IOD) for the estimation of temperature trends. Results show that the main component is the Annual Cycle (AC), particularly at tropopause (CPT, LRT) and in the lower stratosphere (LS) where more than 26.0±2.4% of temperature variability can be explained by AC. The influence of IOD on the variability of the temperature is at highest ratio at CPT and LS, with respectively 12.3±7.3% and 13.1±5.9%. The correlations between IOD and temperature anomalies at UT-LS are barely significant, which are found to be in close agreement with the results obtained by Rosenlof et al. (2008) over the western tropical Pacific Ocean. The temperature trend in the LS reveals a cooling of about −0.90±0.40 K per decade. The cooling trend at LS is found to be in close agreement with the others studies. Trend estimates in the LS suggest that IOD forcing contributes to increasing cooling by about 0.16±0.05 K per decade. Past works have shown that the additional carbon dioxide increase has a minor effect in the LS, and suggested that other effects than ozone and carbon dioxide changes have to be considered, in order to explain the observed temperature changes in the LS. From this study, we can suggest that the SST changes can be considered also, in addition to effects due to ozone and carbon dioxide changes, in order to explain the observed temperature changes in the LS. As a consequence, our results support the assumption that the Indian Ocean may have a slight impact on temperature variability and on temperature change in the LS over Reunion.

The occurrence of a sudden stratospheric warming (SSW) excites disturbances in the mesosphere-lower thermospheric (MLT) wind and temperature. Here, we have examined the high frequency (HF) radar wind data from the South African National Antarctic Expedition, SANAE (72° S, 3° W), a radar which is part of the Super Dual Auroral Radar Network (SuperDARN). Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) on board the Thermosphere-Ionosphere-Mesosphere-Energetics and Dynamics (TIMED) satellite temperature data and National Centre for Environmental Prediction (NCEP) temperature and wind data are used to investigate the dynamical effects of the unprecedented September 2002 SSW in the Antarctica stratosphere and MLT. The mean zonal wind (from SANAE HF radar) at the MLT shows reversal approximately 7 days before the reversal at 10 hPa (from NCEP). This indicates that there was a downwards propagation of circulation disturbance. Westerly zonal winds dominate the winter MLT, but during the 2002 winter there are many periods of westward winds observed compared to other years. The normalised power spectrums of both meridional and zonal winds show presence of planetary waves (of ~14-day period) before the occurrence of the SSW. The SABER vertical temperature profiles indicated the cooling of the MLT region before the SSW event.

In this paper, we present seasonal and nocturnal variations of mesospheric sodium (Na) layer parameters observed over Gadanki (13.5° N, 79.2° E), based on 166 nights during the period from January 2005 to December 2006, for the first time. The total Na content decreases during the evening and reaches a minimum value around midnight and maximum in the early morning. The year-to-year variations illustrate that Na layers reach the peak value close to 93.5 km for the year 2005 and ~93 km for the year 2006 and falls to near zero value around 110 km. Though, seasonal variation of sodium density illustrate maximum values in September, December and March, we require a larger data base for September months to conclude the statement. The column abundance shows maximum during autumn equinox and minimum during winter. The obtained seasonal and nocturnal variation of sodium layer parameters are compared with mid-latitude observations and further possible mechanisms are discussed.

This paper mainly focuses on the validation of temperature estimates derived with the newly launched Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC)/Formosa Satellite 3 (FORMOSAT-3) system. The analysis is based on the radio occultation (RO) data samples collected during the first year observation from April 2006 to April 2007. For the validation, we have used the operational stratospheric analyses including the National Centers for Environmental Prediction - Reanalysis (NCEP), the Japanese 25-year Reanalysis (JRA-25), and the United Kingdom Met Office (MetO) data sets. Comparisons done in different formats reveal good agreement between the COSMIC and reanalysis outputs. Spatially, the largest deviations are noted in the polar latitudes, and height-wise, the tropical tropopause region noted the maximum differences (2–4 K). We found that among the three reanalysis data sets the NCEP data sets have the best resemblance with the COSMIC measurements.

The study presents the climatological characteristics of stratospheric ozone observed over Reunion Island using in-situ (ozonesonde and SAOZ) and satellite (UARS-HALOE, SAGE-II and TOMS) measurements. It uses co-localised ozonesondes (from September 1992 to February 2005) and SAOZ measurements (from January 1993 to December 2004), SAGE-II data from October 1984 to February 1999 (~15 years), HALOE data from January 1991 to February 2005 (~15 years), and NIMBUS/TOMS data from January 1978 to December 2004 (27 years). The satellite measurements correspond to overpasses located nearby Reunion Island (21° S; 55° E). The height profiles of ozone concentration obtained from ozonesonde (0.5–29.5 km) show less bias in comparison with the HALOE and SAGE-II measurements. Though, the satellite (HALOE and SAGE-II) measurements underestimate the tropospheric ozone, they are in good agreement for the heights above 15 km. The bias between the measurements and the normalized ozone profile constructed from the ozonesonde and SAGE-II satellite measurement shows that the SAGE-II measurements are more accurate than the HALOE measurements in the lower stratosphere. The monthly variation of ozone concentration derived from ozonesonde and HALOE shows a nearly annual cycle with a maximum concentration during winter/spring and minimum concentration during summer/autumn months. The time evolution of total column ozone obtained from TOMS, SAOZ and the one computed from ozonesonde and SAGE-II, exhibits similar behaviour with analogous trends as above. The TOMS variation displays a higher value of total column ozone of about 3–5 DU (10%) in comparison with the SAOZ and the integrated ozone from ozonesonde and SAGE-II.

The low-latitude middle atmospheric gravity wave characteristics are presented using 310 nights of Rayleigh lidar observations made at Gadanki (13.5° N, 79.2° E) over the period from March 1998 to December 2002. The gravity wave characteristics are presented in terms of vertical wave number and frequency spectra, along with the estimated potential energy for the four seasons, namely, spring, summer, autumn and winter. The computed wave number spectra for both the stratosphere and the mesosphere are found to differ significantly from a saturated model predicted spectrum. The spectra were found to be shallower at lower wave numbers and steeper at higher wave numbers with transition at ~8.85×10-4 cy/m. The computed frequency spectra seem to follow the model plot with a power law index of -5/3 above a frequency of ~2×10-4 Hz. The estimated potential energy per unit mass increases gradually up to ~60 km and then rather rapidly above this height to reach values of the order of 200J/kg at ~70 km.

A brief experiment was conducted during 24-29 April and 9-10 May 2002, using the MST radar at Gadanki, India, to test the dual-beamwidth method of estimating the turbulence kinetic energy (TKE). Because the beamwidth can be modified on only one polarization at a time at Gadanki, an elliptical beam was used with a modified dual-beamwidth analysis. Estimates of the TKE from the dual-beamwidth method and the traditional method are very similar in regions of light winds (-1). In regions of stronger wind (>~15ms-1) the traditional method often gives TKE0 on the beam parallel to the prevailing wind; on this beam the estimates depend only on the ratio of the beamwidths, which is presumably well-known, and the observed spectral widths. The values of TKE from the dual-beamwidth method are approximately constant with height at 0.2m2s-2 from about 5 to 7.5km during the afternoon during both April and May (all April observations were made between 9:00 and 17:00 local time), and then decrease rapidly to about 0.02m2s-2 by about 9km. The data from May extend over one full diurnal period and the diurnal range of TKE during this period is found to be about 5dB below about 12km and from about 15 to 19km, near the tropopause, with maximum values during local afternoon.

The first Rayleigh lidar observation of a stratopause warming over a tropical site, Gadanki (13.5° N; 79.2° E), is presented in this paper. The warming event was observed on 22-23 February 2001, and found to occur in the stratopause region (~45km). The magnitude of the warming was found to be ~18K with respect to the winter-mean temperature profile derived from the lidar data collected over March 1998 to July 2001. The event observed by the lidar has also been seen in data from the Halogen Occultation Experiment (HALOE) on board the UARS satellite. The zonal-mean temperature at 80° N and the zonal-mean zonal wind at 60° N from the National Centre for Environmental Prediction (NCEP) reanalysis and the European Centre for Medium-Range Weather Forecasts (ECMWF) analysis indicate that a major warming episode took place in the northern polar hemisphere a week before the day of the observation over Gadanki. Eliassen-Palm (E-P) flux calculations from ECMWF analysis show evidence of propagation of planetary-wave activity from high and mid- to low latitudes subsequent to the major warming episode over the pole. Our results support the view that the most likely source mechanism for the observed stratopause warming is the increase in planetary-wave activity.

We present the first scientific results from the Council for Scientific and Industrial Research - National Laser Centre (CSIR-NLC) mobile LIght Detection And Ranging (LIDAR) and its validation and comparison with other ground-based and space-borne measurements. The LIDAR results are compared with aerosol extinction measurements from the Stratosphere Aerosol Gas Experiment (SAGE) II, optical depth derived from sun photometers employed under the AErosol RObotic NETwork (AERONET) and backscatter coefficients simulated from weather balloon humidity measurements.

South Africa's first mobile LIDAR (LIght Detection And Ranging) system is being developed at the National Laser Centre (NLC) of the Council for Scientific and Industrial Research (CSIR) in Pretoria (25°45'S; 28°17'E). The system is designed primarily for remote sensing of the atmosphere. At present, the system is being optimised for measuring vertical atmospheric backscatter profiles of aerosols and clouds. In this paper, we describe the complete LIDAR system, including laser transmission, telescope configuration, data acquisition, data archival and post-processing.

We present the first scientific results from the Council for Scientific and Industrial Research–National Laser Centre (CSIR-NLC) mobile LIght Detection And Ranging (LIDAR) and its validation and comparison with other ground-based and space-borne measurements. The LIDAR results are compared with aerosol extinction measurements from the Stratosphere Aerosol Gas Experiment (SAGE) II, optical depth derived from sun photometers employed under the AErosol RObotic NETwork (AERONET) and backscatter coefficients simulated from weather balloon humidity measurements.

The asymmetric unit of the title compound, C41H31Cl4N3O3, contains two independent molecules with almost identical geometries. The piperidine ring adopts a chair conformation in both molecules, and the dihydroisoxazole rings adopt envelope conformations. The crystal structure is stabilized by C—H...N hydrogen bonds and C—H...π interactions.