1,166 research outputs found
Sukumar, R. — The Asian Elephant : Ecology and Management. Cambridge University Press, Cambridge, 1989,
No full textAsmodé Jean-François. Sukumar, R. — The Asian Elephant : Ecology and Management. Cambridge University Press, Cambridge, 1989,. In: Revue d'Écologie (La Terre et La Vie), tome 46, n°2, 1991. pp. 188-189
Prevalence Of Anxiety, Depression, and Insomnia Among Allied Health Professionals During The Pandemic Outbreak: A Systematic Review And Meta-Analysis
No full textThis systematic review and meta-analysis, conducted by Dr. Leena R David and colleagues, aimed to assess the prevalence of anxiety, depression, and insomnia among allied health professionals (AHPs) during the COVID-19 pandemic and other infectious disease outbreaks. The study identified a critical gap in the existing literature concerning the mental health of AHPs during such crises.
The researchers systematically searched major databases and identified 267 relevant articles, of which five met the inclusion criteria for review. These studies collectively involved 11,148 healthcare professionals, with 831 (7.54%) being AHPs. The selected studies utilized various mental health assessment tools and reported prevalence rates of anxiety and depression among AHPs.
The meta-analysis focused on three of the studies, revealing a pooled effect size of 0.21 for psychological stress and 0.19 for anxiety among AHPs. The results indicated that AHPs experienced moderate levels of psychological distress during infectious disease outbreaks.
Several risk factors were identified, including younger age, gender, social support, and occupational characteristics. The role of supervisors and the provision of accurate information were also highlighted as crucial in managing AHPs' mental health.
Despite the limitations of this study, including potential publication bias and heterogeneity among the selected studies, it provides valuable insights into the mental health challenges faced by AHPs during pandemics. The authors emphasize the need for further research with larger sample sizes and validated measurement tools to better understand and address the mental health of AHPs.
In conclusion, this study underscores the importance of monitoring and supporting the mental well-being of AHPs, who play a vital role in healthcare delivery during infectious disease outbreaks. Policymakers and healthcare organizations are urged to take action to mitigate the impact on AHPs' mental health and ensure their readiness and resilience in facing future public health crises
Semi-classical analysis of scattering of deformed heavy-ions below the Coulomb barrier
No full textA semi-classical calculation is performed to predict spin polarisation observables for elastic heavy ion scattering of a quadrupole deformed projectile from a spinless target below the Coulomb barrier. A method introduced by Sukumar and Brink, based on a path integral formalism and a consistent quantum-mechanical treatment of both the relative motion and internal degrees of freedom is used. This method is an improvement on earlier semi-classical calculations based on the Alder and Winther method which, in the absence of excitation, predict cross-sections which are independent of the polarisation of the initial spin state. The expressions developed by Sukumar and Brink are evaluated to first order in the quadrupole moment of the projectile. Polarisation observables are compared to both quatum-mechanical coupled channels calculations and other approximate semi-classical calculations; good agreement is found. For backward angles, simple expressions for polarisation observables valid to first order in the quadrupole moment are given. © 1995
5716 Ani Con Sukumar
No full textAbstract Ivory poaching has been a serious problem in Asian elephant (Elephas maximus) populations. Reliable records of elephants killed and ivory harvested are generally unavailable. We have used a simulation modelling approach to estimate the numbers of male elephants killed and the quantities of ivory harvested over a 20 year period in the Periyar Reserve of southern India. The age-structured Leslie matrix projection model was modified for this purpose by considering three segments (female, tusked male and tuskless male), relating fecundity to adult sex ratio and iteratively simulating tusked male mortality rates so as to match the observed elephant population structure at Periyar. Four different scenarios of poaching all gave very similar results. We estimate conservatively that 336-388 tuskers have been poached and 3256-3334 kg of ivory harvested by poachers over the 20 year period. The maximum harvest came from the 10-20 year age class. Trends in various demographic parameters such as population numbers, tusked male to tuskless male ratios and female fecundity are described. The implications of ivory poaching and the extremely skewed sex ratios for the conservation and management of the elephant population at Periyar are discussed
The Nation and its citizens: Tales of Bondage and Belonging
No full textThe Nation and Its Citizens: Tales of Bondage and Belonging is about nationalism as a uniquely modern political doctrine, shaped by the lived experience of citizens. Nationalism has changed in its appeal through history, as have its manifestations. Getting to know these may be part of the challenge of negotiating the ongoing turmoil, both internal and external to the nation.
In addressing these issues, this book offers several propositions on how the construct of ‘identity’ is crafted, with all its power to influence modern politics. It then explores how well India’s practice of republican democracy has lived up to the competing dynamics of identity and equality.
As India celebrates 75 years of Independence, author Sukumar Muralidharan takes the readers on a journey into how the sense of fellow-feeling and mutual dependence of the nation are consolidated, and under what circumstances these could fray. The Nation and Its Citizens offers many fresh perspectives in understanding India’s unique political trajectory
R Markdown code to convert bird point count data to ebird bulk upload CSV file
No full textThe .Rmd file contains the R code (script in R Markdown format) used for converting bird point count data and locations from the following dataset to prepare a CSV file in the eBird record format for bulk upload of the data to the eBird citizen science portal (https://www.ebird.org/):
Raman TRS et al. 2022. Data on bird communities and vegetation in relation to altitude and habitat alteration in the Kalakad - Mundanthurai Tiger Reserve, Tamil Nadu, India , Dryad, Dataset, https://doi.org/10.5061/dryad.41ns1rngj
The .html file contains the knit version of the same R markdown code.The dataset contains data on bird communities and habitat collected between 1997 and 1999 from Kalakad Mundanthurai Tiger Reserve, Tamil Nadu, India, related to the following two publications:
Raman, T. R. S., Joshi, N. V. & Sukumar, R. 2005. Tropical rainforest bird community structure in relation to altitude, tree species composition, and null models in the Western Ghats, India. Journal of the Bombay Natural History Society 102: 145-157. https://archive.org/details/journalofbomb10222005bomb/page/145/mode/2up
Raman, T. R. S. & Sukumar, R. 2002. Responses of tropical rainforest birds to abandoned plantations, edges, and logged forest in the Western Ghats, India. Animal Conservation 5: 201-216. http://dx.doi.org/10.1017/S136794300200225
Silencing of the retinoic acid receptor beta (RAR beta) gene by hypermethylation in human breast cancer
No full textStudies On Endocrine And Behavioral Assessment Of Reproductive Status In Asian Elephants (Elephas Maximus)
No full textThe Asian elephant (Elephas maximus), a charismatic ‘flagship species’, is threatened by extinction in the wild, and the development of self-sustainable captive populations is a key conservation challenge. A third of the Asian elephant population is presently in captivity and information on the reproductive status, especially in females, is still lacking to a large extent. The onset of estrus in female Asian elephants is not associated with any visible physical signs, thus making the assessment of the reproductive status rather difficult. One approach to understanding reproductive cyclicity of animals is through generating profiles of reproductive hormones in blood (Wiseman et al. 1983; Brown et al. 1999, 2004). Profiles of reproductive hormones such as progesterone (P4), estrogen, luteinizing hormone and follicle stimulating hormone have already being demonstrated in Asian elephants (Brown et al. 1999, 2004; Brown 2000). In these studies, the reproductive status of females, maintained in zoos/captivity, was characterized based on circulating levels of hormones in blood samples. This is difficult to implement in the case of semi-captive or wild populations of elephants due to practical, legal and ethical considerations. In order to overcome this problem and to better understand the estrous status of female elephants, it is important to develop and validate non-invasive methods to monitor the reproductive status of female Asian elephants.
An alternative approach to evaluating the reproductive status of females is to consider behavioral responses shown by males towards chemical signals produced by females to advertise their reproductive status. In order to understand the reproductive status of the individual belonging to the opposite sex, studies have shown that elephants rely on a variety of chemical signals produced in biological fluids such as urine, temporal gland secretion, inter-digital gland secretion, etc. (Krishnan 1972; Rasmussen & Schulte 1998). Chemical signaling is one of the prominent modes of communication in elephants, especially with respect to locating potential mates (Sukumar 2003). Thus, in most cases, elephants usually employ specific behavioral responses, for example sniff, check and place behaviors of trunk, for investigating the reproductive status of the conspecific individual, belonging either to the same or the opposite sex (Rasmussen et al. 1996; Schulte & Rasmussen 1999; Bagley et al. 2006).
The objectives of the thesis are two-fold. First, to develop a non-invasive method of reproductive monitoring from fecal hormonal metabolites and also to understand the possible role of feces as an inter-sexual signal. The main body of thesis is divided into four chapters.
1) Development and validation of a non-invasive method to estimate progesterone metabolite in feces, to monitor the reproductive cyclicity of female elephants (Chapter 2).
2)Generation and characterization of progesterone and its metabolite, 5α-P-3-OH, profiles of semi-captive females using the developed non-invasive method to measure fecal metabolites (Chapter 3).
3) Validation of developed methodology and assay systems to a wild-population of female elephants (Chapter 4). 4) Feces as a potential source for inter-sexual chemical signaling in Asian elephants (Chapter 5).
The above studies were carried out on semi-captive male and female elephants maintained in the forest camps of Mudumalai Wildlife Sanctuary (MWLS), Tamil Nadu and Bandipur National Park (BNP), Karnataka, India (Chapters 2, 3 and 5). For Chapter-4, free-ranging females of the MWLS were examined.
1. Development and validation of a non-invasive method to estimate progesterone metabolite in feces, to monitor the reproductive cyclicity of female elephants
Niemuller et al. (1993) generated a profile of the progesterone metabolite, 5βpregnanetriol, to assess the estrous phase of Asian elephants based on non-invasive urine sampling. However, the collection of urine is difficult and to some extent impossible in the case of semi-captive and as well as that of wild elephants. Thus, the method of choice in this study was the development and validation of a non-invasive approach to measure fecal progesterone metabolites to assess reproductive status of females. Sampling was carried out at monthly intervals on three female elephants at the MWLS forest camp, while three other females maintained at the BNP forest camp were sampled fortnightly. An enzyme linked immuno-sorbent assay was developed to measure the concentration of the progesterone metabolite, 5α-P-3OH in the fecal samples of the semi-captive females. Using varying concentrations of the hapten (5α-P3OH), from low (0.1 mM) to high (1 mM), a standard curve was first generated, which had a linear range between 0.25 mM to 62.5 mM, with an EC50 of 1.37 mM. The linear range was then used to detect the concentrations of 5α-P-3OH in the fecal samples of females examined. The non-invasive method was further validated as there existed a positive correlation (p<0.1) between the levels of fecal 5α-P-3OH and that of concentration of circulating P4, measured in blood samples. This is the first valid documentation of a non-invasive method based on fecal progesterone metabolite pattern in order to assess the reproductive status of the female Asian elephants.
2. Generation and characterization of reproductive hormone profiles of semi-captive females using the developed non-invasive method to measure fecal metabolites With the establishment of a non-invasive method to understand occurrence of estrus in female elephants (described in Chapter 2), attempts were made to generate hormonal profiles over a longer time interval through more frequent sampling. Based on sampling at weekly intervals, the concentrations of both fecal 5α-P-3OH and that of native P4 hormone in the blood were determined, and the females were then identified as belonging to different reproductive states of hormonal cycling (follicular and luteal phases), non-cycling and pregnant categories.
Of the 7 females sampled at both MWLS and BNP, three distinct categories of hormone-metabolite profiles emerged. The first category included four females that showed regular cyclicity throughout the sampling period, as monitored through the measurement of fecal 5α-P-3OH and serum P4 levels. The estrous cycle of all the four females was divided into two phases (follicular and luteal), based on the patterns of fecal 5α-P-3OH and serum P4 concentrations. The follicular phase of the estrous cycle was assigned when the values of both fecal 5α-P-3OH and serum P4 remained below 0.3 µg/gm and 0.3 ng/ml, respectively, for a considerable time period (viz. >2 wk). However, the luteal phase was characterized, when the levels of fecal 5α-P-3OH and serum P4 remained at or above 0.3 µg/gm and 0.3 ng/ml respectively, over a period of more than 2 - 3 wk.
The second category had two females showing a ‘flat-lining pattern’ for the levels of fecal 5α-P-3OH and serum P4 concentrations, without any peak or dip in their concentrations. Since the reproductive pattern for both these females was flat-lined throughout their sampling period (51 wk), maintaining the levels of fecal 5α-P-3OH and serum P4 below 0.3 µg/gm and 0.3 ng/ml respectively, the females were considered to be non-cycling or anestrus. The third category had one female in which the levels of both fecal 5α-P-3OH and serum P4 measured were consistently high throughout the entire sampling period (26 wk). The levels of both fecal -P-3OH and serum P4 were above 0.3 µg/gm and 0.3 ng/ml, respectively. At the end of the sampling period, this female delivered a male calf; thus, the measured concentrations of fecal 5α-P-3OH and serum P4 signified the levels maintained during the gestational phase of this female.
Sampling and hormonal analyses were also carried out for a male in the MWLS forest camps to investigate the baseline concentrations of fecal 5α-P-3OH and serum P4. The male showed consistently low concentrations of both fecal 5α-P-3OH and serum P4 throughout the sampling period (16 wk), below the margin of 0.3 µg/gm and 0.3 ng/ml, respectively.
In this part of the study, it was confirmed that the reproductive status of a female elephant can be correctly assessed on the basis of measurements of fecal 5α-P-3OH alone, with repeated sampling of the female over a longer time scale. It was also shown that the strength of the positive correlation between the concentrations of the fecal 5α-P3OH and the serum P4 increased (p<0.01) for a larger sample size than that obtained for a comparatively smaller sample (described in Chapter 2).
3. Validation of developed methodology and assay systems to wild-population of female elephants
So far, the non-invasive method to estimate fecal progesterone metabolite in order to predict occurrence of estrus of elephants was largely applied to semi-captive females (described in Chapters 2, 3). However, the necessity of such a method is being recognized for assessing the reproductive status of free-ranging females. Several findings have described differences in the rate and type of steroid metabolite excretion among individuals maintained under different diet regimes (Wasser et al. 1993; Smith et al. 2006). For instance, female elephants in the forest camps are provided with supplementary diet consisting of sugarcane, rice and millets. This diet is strikingly different from the feeding materials consumed by wild/free-ranging elephants (Sukumar 2003). Therefore, differences in dietary components can potentially influence the fecal steroid metabolites’ excretory patterns shown by semi-captive vis-a-vis wild females, which can affect the validity of measuring fecal 5α-P-3OH to predict females’ reproductive status. In order to examine this problem, the non-invasive method was applied to the population of wild elephants in the forests of MWLS, through random one time sampling of 30 individual female elephants. The steroid extraction efficiency (73 ± 11.0%, mean ± S.D., n =30) determined for the fecal samples collected from the wild females was not significantly different from the coefficient calculated in the case of the semi-captive females (80 ± 4.3%, mean ± S.D., n = 38). This indicated that dietary differences between wild and captive elephants did not influence levels of fecal hormonal metabolites in feces, unlike earlier observations on baboons (Wasser et al. 1993), old world primates (Wasser et al. 1988) and sheep (Smith et al. 2006). The values of the fecal allopregnanolone determined in the case of the wild females, ranged
from as low as 0.06 µg/gm to as high as 23µg/gm of the sample, thus showing the heterogeneity of the samples, indicating that the females may be belonging to different reproductive phases. However, since sampling was carried out randomly, with an adult female being sampled just once, at this stage, it is not possible to identify or elaborate on the reproductive phase of the females. This is the first study reporting the values of the fecal progesterone metabolite in female Asian elephants in the wild. Further studies may be required to carry out long term monitoring of the wild females, through repeated collection of fecal samples over time from particular female.
4. Feces as a potential source for inter-sexual chemical signaling in Asian elephants
In this Chapter-5, behavioral trials were conducted on male elephants to understand the role of fecal matter in conveying inter-sexual chemical signals. This was demonstrated by analyses of specific chemosensory behavioral responses shown by males towards the fecal samples of females that were strangers and belonging to different reproductive stages. Males showed four prominent behavioral responses namely ‘distant sniff’, ‘close sniff’, ‘check’ and ‘place’ towards the fecal samples of females. The sum of frequencies of these four responses (distant sniff, close sniff, check and place) was much higher for samples of the follicular (pre-ovulatory) phase females as compared to those of the luteal (post-ovulatory) phase females (p<0.005). Thus, for the first time, it was shown that male elephants are able to discriminate the different reproductive phases of females based on their specific behavioral response towards the fecal samples of the opposite sex.
In conclusion, the thesis has focused on understanding and providing new insights regarding the reproductive biology of the female Asian elephants. This has been achieved through the development of the non-invasive method based on measuring the concentrations of the fecal progesterone metabolite and through the analyses of the chemosensory responses performed by the males towards the fecal samples of strange females. These methods can potentially be applied to the populations of both wild and captive/semi-captive female elephants in order to evaluate their reproductive status, through non-invasive measures. The information derived from the application of such
methods will help in understanding the reproductive potential of the wild elephants under various environmental and ecological conditions. Further, the non-invasive measurement of reproductive hormones will help in monitoring the reproductive state of the individuals and thus aid in planning strategies for the welfare and management of the elephants maintained in captive or semi-captive conditions
Pharmacogenomic and mechanistic studies on dietary factors in chemoprevention of cancer
No full textPharmacogenomic profiling of cancer has recently seen much activity with the accessibility of the newest generation of high-throughput platforms and technologies. A myriad of mechanistic studies have been devoted to identifying dietary factors that can help prevent cancer, with evidence gleaned from epidemiologic studies revealing an inverse correlation between the intake of cruciferous vegetables and the risk of certain types of cancer. To develop a comprehensive understanding of cancer pathogenesis, and potential for chemopreventive intervention with dietary factors, an integrated approach that encompasses both pharmacogenomic and mechanistic aspects is desirable. Our transcriptomic profiling of butylated hydroxyanisole-induced Nuclear Factor-E2-related factor 2 (Nrf2)-dependent genes in Nrf2-deficient mice identified several germane molecular targets for prevention. Toxicogenomic analyses of endoplasmic reticulum stress inducer tunicamycin in Nrf2-deficient mice elucidated Nrf2-regulated unfolded protein response effects. Mechanistic studies on a combination of sulforaphane and (-) epigallocatechin-3-gallate in HT-29 AP-1 (Activator Protein-1) cells revealed a synergy in colon cancer chemoprevention. Pharmacogenomic studies of this combination in PC-3 AP-1 cells provided a discursive framework for understanding putative crosstalk between Nrf2 and AP-1 in prostate cancer chemoprevention. Regulatory potential for concerted modulation of Nrf2 and Nuclear Factor-κB (Nfκb1) in inflammation and carcinogenesis was delineated by bioinformatic analyses. Metabolomic approaches identified potential prognostic biomarkers in human prostate cancer. Differential biological networks in prostate cancer were elicited in androgen-dependent 22Rv1 cells, androgen- and estrogen-dependent LNCaP cells and androgen-independent DU 145 and PC-3 cells. Taken together, our identification of Nrf2-regulated molecular targets by expression profiling using dietary factors, synergistic effects in combinatorial use of dietary factors in colon cancer, regulatory studies on crosstalk between Nrf2 and AP-1 in prostate cancer, bioinformatic analyses of concerted modulation of Nrf2 and Nfkb1 in inflammation and carcinogenesis, metabolomic identification of biomarkers, and delineation of target hubs in differential prostate cancer biological networks, greatly enhance our understanding of the transcriptional circuitry in cancer and important master regulatory nodes including Nrf2 that might potentially be exploited for chemopreventive intervention with dietary factors.Ph.D.Includes bibliographical references (p. 311-331)
Modeling Quasi-Static Crack Growth with the Extended Finite Element Method. Part II: Numerical Applications
No full textIn Part I (Sukumar and Prevost 2003), we described the implementation of the extended finite element method (X-FEM) within Dynaflow, a standard finite element package. In our implementation, we focused on 2-dimensional crack modeling in linear elasticity. For crack modeling in the X-FEM, a discontinuous function and the near-tip asymptotic functions are added to the finite element approximation using the framework of partition of unity. This permits the crack to be represented without explicitly meshing the crack surfaces and crack propagation simulations can be carried out without the need for any remeshing. In this paper, we present numerical solutions for the stress intensity factor for crack problems, and also conduct crack growth simulations with the X-FEM. Numerical examples are presented with a two-fold objective: first to show the efficacy of the X-FEM implementation in Dynaflow; and secondly to demonstrate the accuracy and versatility of the method to solve challenging problems in computational failure mechanics
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