166 research outputs found

    Dendroclimatic analysis of teak (Tectona grandis L. f.) annual rings from two locations of peninsular India

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    Climate-related tree-growth variability in teak (Tectona grandis L. f.) has been studied based on response function analysis from dry deciduous forests of Mundagod (Karnataka) and Chandrapur (Maharashtra), peninsular India, representing two ecological zones. Rainfall during the monsoon months of the current year was found to be positively associated with radial growth of teak at both sites, whereas premonsoon April rainfall was found to be negatively associated. Rainfall and temperature of the current year during March have positive influence on the growth of teak at Chandrapur and Mundagod respectively. Furthermore, rainfall during October of the preceding year showed negative influence on tree growth at Mundagod and positive influence at Chandrapur, which might be due to the difference in relative humidity and soil type at both the locations, apart from soil moisture

    Effect of growth rate and latewood content on basic density of wood from 120-to 154-Year-old natural-grown Teak (Tectona grandis L. f.)

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    The relationship between the radial variations of growth ring features and basic density were investigated in juvenile and mature wood for five 120-to150-year-old trees of Tectona grandis L. grown naturally in moist deciduous forest of Thane,Maharashtra. The study showed that the mean basic density of growth rings in juvenile wood was 0.665 (0.602-0.702) g cm-3 and 0.613 (0.562-0.665) g cm-3 in mature wood. The annual growth in juvenile period was high with a ring width mean of 4.03 mm and the latewood content represented 76.36 % of the annual growth, while in mature period was low with a ring width mean of 1.24 mm and the latewood content represented 59.41% of the annual growth. The patterns of radial variation of ring width, latewood content and basic density were more inherent in the juvenile wood than mature wood of all trees due to cambial ageing. The basic density of five individual trees showed an insignificant correlation between ring-width and latewood content in juvenile wood, whereas a significant positive correlation was found in mature wood of most of individual trees. The mean ring width value of all trees showed a highly significant positive correlation with basic density in both types of wood but mean latewood content showed a non-significant or low significant correlatio

    Intra-annual oxygen isotope variations in Central Indian teak cellulose: possibility of improved resolution for past monsoon reconstruction

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    A clear seasonal cycle has been detected in the intraannual oxygen isotope variations (δ18O) of cellulose from several annual growth rings of teak trees that grew in central India. This persistent cycle is marked by higher δ18O values at the ring boundaries and lower δ18O values at intermediate parts. The amplitude of this seasonal cycle varies up to 6.8‰. Based on the pattern of teak growth reported in the literature and a plant physiological model that interprets the δ18O of plant cellulose, it seems possible to identify subsections of a ring that formed during pre-monsoon, peak-monsoon and post-monsoon. Comparison of the δ18O profile of a ring (year AD 1971), analysed with the highest resolution, and a model profile based on concurrent local meteorological data indicates the possibility of achieving a ~20 day resolution in monsoon reconstruction by intra-annual δ18O measurements

    New Paradigms for Access Control in Constrained Environments

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    International audienceThe Internet of Things (IoT) is here, more than 10 billion units are already connected and five times more devices are expected to be deployed in the next five years. Technological standarization and the management and fostering of rapid innovation by governments are among the main challenges of the IoT. However, security and privacy are the key to make the IoT reliable and trusted. Security mechanisms for the IoT should provide features such as scalability, interoperability and lightness. This paper adresses authentication and access control in the frame of the IoT. It presents Physical Unclonable Functions (PUF), which can provide cheap, secure, tamper-proof secret keys to authentify constrained M2M devices. To be successfully used in the IoT context, this technology needs to be embedded in a standardized identity and access management framework. On the other hand, Embedded Subscriber Identity Module (eSIM) can provide cellular connectivity with scalability, interoperability and standard compliant security protocols. The paper discusses an authorization scheme for a constrained resource server taking advantage of PUF and eSIM features. Concrete IoT uses cases are discussed (SCADA and building automation)

    Estimation of past atmospheric carbon dioxide levels using tree-ring cellulose Delta 13 C

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    We study the applicability of the Farquhar model for carbon isotopic discrimination (change in carbon isotopic composition from air CO2 to tree-ring cellulose) in C3 plants to trees growing in the field. Two new carbon isotope datasets from Himalayan conifers with published data from another eight sites across the world show disparate trends in the plot of carbon isotope discrimination versus atmospheric carbon dioxide concentration, in contrast to the model prediction of absence of any trend. This is because the model assumes that the tree adjusts its stomatal conductance for water-use efficiency to maintain a constant ratio of carbon dioxide concentrations inside and outside the leaf and treats the diffusive and biochemical fractionation factors as constants. By introducing a simple linear dependence of these fractionation factors with ambient temperature and humidity, we have enhanced the applicability of the model to naturally growing trees. Further, despite the disparate trends exhibited by the 10 trees, we show using the inverse modelling that it is possible to derive a unique record of past atmospheric CO2 concentrations using tree cellulose 13C data. The reconstructions also replicate the summer pCO2 gradient from tropics to mid-latitudes. We also discuss the merits and demerits of the model, and compare the model-derived pCO2 with that of the ice core-based records from Law Dome

    Disease knowledge after an educational program in patients with GERD – a randomized controlled trial

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    <p>Abstract</p> <p>Background</p> <p>Patient education has proved beneficial in several but not all chronic disease. Inconsistent findings may rely on varying educational effects of various programs and differential effects on subgroups of patients. Patients' increase in disease knowledge may serve as a feedback to the educator on how well the education program works – but may not be associated to relevant clinical outcomes like quality of life (QoL). This study aimed to investigate the effects of a group based education program for patients with gastroesophageal reflux disease (GERD) on disease knowledge and the association between knowledge and QoL.</p> <p>Methods</p> <p>Patients with GERD were randomly allocated to education (102 patients) or control (109 patients). The education program was designed as a structured dialogue conveying information about pathophysiology, pharmacological and non-pharmacological treatment of GERD, patients' rights and use of healthcare. Outcomes were a 24 item knowledge test on GERD (score 0 – 24) 2 and 12 months after the educational program and disease specific and general QoL (Digestive symptoms and disease impact, DSIQ, and General Health Questionnaire, GHQ).</p> <p>Results</p> <p>Patients allocated to education achieved higher knowledge test scores than controls at 2 months (17.0 vs. 13.1, p < 0.001) and at 12 months (17.1 vs. 14.0, p < 0.001) follow-up. Knowledge test score was positively associated with having completed advanced school and inversely related to psychiatric illness and poor QoL as perceived by the patients at the time of inclusion. Overall, changes in knowledge test score were not associated with change in QoL.</p> <p>Conclusion</p> <p>A group based education program for patients with GERD designed as a structured dialogue increased patients' disease knowledge, which was retained after 1 year. Changes in GERD-knowledge were not associated with change in QoL.</p> <p>Trial registration</p> <p>ClinicalTrials.gov: NCT0061850</p

    The MeerKAT Absorption Line Survey (MALS) data release I: Stokes I image catalogs at 1-1.4 GHz

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    The MeerKAT Absorption Line Survey (MALS) has observed 391 telescope pointings at L-band (900 - 1670 MHz) at ÎŽâ‰Č\delta\lesssim +20deg⁥+20\deg. We present radio continuum images and a catalog of 495,325 (240,321) radio sources detected at a signal-to-noise ratio (SNR) >>5 over an area of 2289 deg2^2 (1132 deg2^2) at 1006 MHz (1381 MHz). Every MALS pointing contains a central bright radio source (S1 GHz≳0.2S_{1\,\mathrm{GHz}} \gtrsim 0.2 Jy). The median spatial resolution is 12â€Čâ€Č12^{\prime\prime} (8â€Čâ€Č8^{\prime\prime}). The median rms noise away from the pointing center is 25 ÎŒ\muJy beam−1^{-1} (22 ÎŒ\muJy beam−1^{-1}) and is within ∌\sim 15% of the achievable theoretical sensitivity. The flux density scale ratio and astrometric accuracy deduced from multiply observed sources in MALS are less than 1% (8% scatter) and 1â€Čâ€Č1^{\prime\prime}, respectively. Through comparisons with NVSS and FIRST at 1.4 GHz, we establish the catalog's accuracy in the flux density scale and astrometry to be better than 6% (15% scatter) and 0.8â€Čâ€Č0.8^{\prime\prime}, respectively. The median flux density offset is higher (9%) for an alternate beam model based on holographic measurements. The MALS radio source counts at 1.4 GHz are in agreement with literature. We estimate spectral indices (α\alpha) of a subset of 125,621 sources (SNR>>8), confirm the flattening of spectral indices with decreasing flux density and identify 140 ultra steep-spectrum (α<−1.3\alpha<-1.3) sources as prospective high-zz radio galaxies (z>2z>2). We have identified 1308 variable and 122 transient radio sources comprising primarily of AGN that demonstrate long-term (26 years) variability in their observed flux densities. The MALS catalogs and images are publicly available at https://mals.iucaa.in.Comment: 64 pages, 25 figures, accepted for publication in the ApJS (full version of the paper with complete tables is available at DR1 release notes

    Current perspectives on coronavirus disease 2019 and cardiovascular disease: a white paper by the JAHA editors

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    Coronavirus Disease 2019 (COVID‐19) has infected more than 3.0 million people worldwide and killed more than 200,000 as of April 27, 2020. In this White Paper, we address the cardiovascular co‐morbidities of COVID‐19 infection; the diagnosis and treatment of standard cardiovascular conditions during the pandemic; and the diagnosis and treatment of the cardiovascular consequences of COVID‐19 infection. In addition, we will also address various issues related to the safety of healthcare workers and the ethical issues related to patient care in this pandemic

    Molecular Mechanisms Generating and Stabilizing Terminal 22q13 Deletions in 44 Subjects with Phelan/McDermid Syndrome

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    In this study, we used deletions at 22q13, which represent a substantial source of human pathology (Phelan/McDermid syndrome), as a model for investigating the molecular mechanisms of terminal deletions that are currently poorly understood. We characterized at the molecular level the genomic rearrangement in 44 unrelated patients with 22q13 monosomy resulting from simple terminal deletions (72%), ring chromosomes (14%), and unbalanced translocations (7%). We also discovered interstitial deletions between 17–74 kb in 9% of the patients. Haploinsufficiency of the SHANK3 gene, confirmed in all rearrangements, is very likely the cause of the major neurological features associated with PMS. SHANK3 mutations can also result in language and/or social interaction disabilities. We determined the breakpoint junctions in 29 cases, providing a realistic snapshot of the variety of mechanisms driving non-recurrent deletion and repair at chromosome ends. De novo telomere synthesis and telomere capture are used to repair terminal deletions; non-homologous end-joining or microhomology-mediated break-induced replication is probably involved in ring 22 formation and translocations; non-homologous end-joining and fork stalling and template switching prevail in cases with interstitial 22q13.3. For the first time, we also demonstrated that distinct stabilizing events of the same terminal deletion can occur in different early embryonic cells, proving that terminal deletions can be repaired by multistep healing events and supporting the recent hypothesis that rare pathogenic germline rearrangements may have mitotic origin. Finally, the progressive clinical deterioration observed throughout the longitudinal medical history of three subjects over forty years supports the hypothesis of a role for SHANK3 haploinsufficiency in neurological deterioration, in addition to its involvement in the neurobehavioral phenotype of PMS
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