1,617 research outputs found

    Assigning conservation value and identifying hotspots of endemic rattan diversity in the Western Ghats, India

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    Rattans, or canes, are one of the most important non-timber forest products supporting the livelihood of many forest-dwelling communities in South and North-eastern India. Due to increased demand for rattan products, rattans have been extracted indiscriminately from the Western Ghats, a 1600-km mountain chain running parallel to the west coast of India. Extensive harvesting, loss of habitat and poor regeneration has resulted in dwindling rattan populations, necessitating an urgent attempt to conserve existing rattan resources. In this study, using niche-modelling tools, an attempt has been made to identify areas of high species richness of rattans in the Western Ghats, one of the mega-diversity regions of the world. We have also developed conservation values for 21 economically important and endemic rattans of the Western Ghats. We identified at least two to three sites of extremely high species richness outside the existing protected area network that should be prioritized for in situ conservation. This study emphasizes the need to develop strategies for the long-term conservation of rattans in the Western Ghats, Indi

    A study of strong pulses detected from PSR B0656+14 using Urumqi 25-m radio telescope at 1540MHz

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    We report on the properties of strong pulses from PSR B0656+14 by analyzing the data obtained using Urumqi 25-m radio telescope at 1540 MHz from August 2007 to September 2010. In 44 hrs of observational data, a total of 67 pulses with signal-to-noise ratios above a 5-{\sigma} threshold were detected. The peak flux densities of these pulses are 58 to 194 times that of the average profile, and the pulse energies of them are 3 to 68 times that of the average pulse. These pulses are clustered around phases about 5 degrees ahead of the peak of the average profile. Comparing with the width of the average profile, they are relatively narrow, with the full widths at half-maximum range from 0.28 to 1.78 degrees. The distribution of pulse-energies of the pulses follows a lognormal distribution. These sporadic strong pulses detected from PSR B0656+14 are different in character from the typical giant pulses, and from its regular pulses.Comment: 6 pages, 3 figures, Accepted by RA

    Adrenal ganglioneuroma with hepatic metastasis

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    Ganglioneuroma is the most differentiated tumor of neural crest origin and rarely arises in the adrenal gland. Ganglioneuroma is typically known to be benign, but very rarely can metastasize to distant sites. We report a case of a 31-year-old man with a huge adrenal mass with hepatic metastases

    Testing the paradox of enrichment along a land use gradient in a multitrophic aboveground and belowground community

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    In the light of ongoing land use changes, it is important to understand how multitrophic communities perform at different land use intensities. The paradox of enrichment predicts that fertilization leads to destabilization and extinction of predator-prey systems. We tested this prediction for a land use intensity gradient from natural to highly fertilized agricultural ecosystems. We included multiple aboveground and belowground trophic levels and land use-dependent searching efficiencies of insects. To overcome logistic constraints of field experiments, we used a successfully validated simulation model to investigate plant responses to removal of herbivores and their enemies. Consistent with our predictions, instability measured by herbivore-induced plant mortality increased with increasing land use intensity. Simultaneously, the balance between herbivores and natural enemies turned increasingly towards herbivore dominance and natural enemy failure. Under natural conditions, there were more frequently significant effects of belowground herbivores and their natural enemies on plant performance, whereas there were more aboveground effects in agroecosystems. This result was partly due to the “boom-bust” behavior of the shoot herbivore population. Plant responses to herbivore or natural enemy removal were much more abrupt than the imposed smooth land use intensity gradient. This may be due to the presence of multiple trophic levels aboveground and belowground. Our model suggests that destabilization and extinction are more likely to occur in agroecosystems than in natural communities, but the shape of the relationship is nonlinear under the influence of multiple trophic interactions.

    Caspase-3 dependent nitrergic neuronal apoptosis following cavernous nerve injury is mediated via RhoA and ROCK activation in major pelvic ganglion

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    Axonal injury due to prostatectomy leads to Wallerian degeneration of the cavernous nerve (CN) and erectile dysfunction (ED). Return of potency is dependent on axonal regeneration and reinnervation of the penis. Following CN injury (CNI), RhoA and Rho-associated protein kinase (ROCK) increase in penile endothelial and smooth muscle cells. Previous studies indicate that nerve regeneration is hampered by activation of RhoA/ROCK pathway. We evaluated the role of RhoA/ROCK pathway in CN regulation following CNI using a validated rat model. CNI upregulated gene and protein expression of RhoA/ROCK and caspase-3 mediated apoptosis in the major pelvic ganglion (MPG). ROCK inhibitor (ROCK-I) prevented upregulation of RhoA/ROCK pathway as well as activation of caspase-3 in the MPG. Following CNI, there was decrease in the dimer to monomer ratio of neuronal nitric oxide synthase (nNOS) protein and lowered NOS activity in the MPG, which were prevented by ROCK-I. CNI lowered intracavernous pressure and impaired non-adrenergic non-cholinergic-mediated relaxation in the penis, consistent with ED. ROCK-I maintained the intracavernous pressure and non-adrenergic non-cholinergic-mediated relaxation in the penis following CNI. These results suggest that activation of RhoA/ROCK pathway mediates caspase-3 dependent apoptosis of nitrergic neurons in the MPG following CNI and that ROCK-I can prevent post-prostatectomy ED

    On the Security of Delegation in Access Control Systems

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    Abstract. Delegation is a mechanism that allows a user A to act on another user B’s behalf by making B’s access rights available to A. It is well recognized as an important mechanism to provide resiliency and flexibility in access control systems, and has gained popularity in the research community. However, most existing literature focuses on modeling and managing delegations. Little work has been done on understanding the impact of delegation on the security of existing access control systems. In particular, no formal notion of security with respect to delegation has been proposed. Many existing access control systems are designed without having delegation in mind. Simply incorporating a delegation module into those systems may cause security breaches. This paper focuses on the security aspect of delegation in access control systems. We first give examples on how colluding users may abuse the delegation sup-port of access control systems to circumvent security policies, such as separation of duty. As a major contribution, we propose a formal notion of security with respect to delegation in access control systems. After that, we discuss potential mechanisms to enforce security. In particular, we design a novel source-based en-forcement mechanism for workflow authorization systems so as to achieve both security and efficiency.

    Evaluation of serum glycoprotein biomarker candidates for detection of esophageal adenocarcinoma and surveillance of Barrett’s esophagus

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    Esophageal adenocarcinoma (EAC) is thought to develop from asymptomatic Barrett’s esophagus (BE) with a low annual rate of conversion. Current endoscopy surveillance for BE patients is probably not cost-effective. Previously, we discovered serum glycoprotein biomarker candidates which could discriminate BE patients from EAC. Here, we aimed to validate candidate serum glycoprotein biomarkers in independent cohorts, and to develop a biomarker candidate panel for BE surveillance. Serum glycoprotein biomarker candidates were measured in 301 serum samples collected from Australia (4 states) and USA (1 clinic) using previously established lectin magnetic bead array (LeMBA) coupled multiple reaction monitoring mass spectrometry (MRM-MS) tier 3 assay. The area under receiver operating characteristic curve (AUROC) was calculated as a measure of discrimination, and multivariate recursive partitioning was used to formulate a multimarker panel for BE surveillance. Complement C9 (C9), gelsolin (GSN), serum paraoxonase/arylesterase 1 (PON1) and serum paraoxonase/lactonase 3 (PON3) were validated as diagnostic glycoprotein biomarkers in lectin pull-down samples for EAC across both cohorts. A panel of 10 serum glycoprotein biomarker candidates discriminated BE patients not requiring intervention [BE+/- low grade dysplasia] from those requiring intervention [BE with high grade dysplasia (BE-HGD) or EAC] with an AUROC value of 0.93. Tissue expression of C9 was found to be induced in BE, dysplastic BE and EAC. In longitudinal samples from subjects that have progressed towards EAC, levels of serum C9 were significantly (P\u3c0.05) increased with disease progression in EPHA (erythroagglutinin from Phaseolus vulgaris) and NPL (Narcissus pseudonarcissus lectin) pull-down samples. The results confirm alteration of complement pathway glycoproteins during BE-EAC pathogenesis. Further prospective clinical validation of the confirmed biomarker candidates in a large cohort is warranted, prior to development of a first-line BE surveillance blood test

    Human African trypanosomiasis

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    Human African trypanosomiasis (sleeping sickness) occurs in sub-Saharan Africa. It is caused by the protozoan parasite Trypanosoma brucei, transmitted by tsetse flies. Almost all cases are due to Trypanosoma brucei gambiense, which is indigenous to west and central Africa. Prevalence is strongly dependent on control measures, which are often neglected during periods of political instability, thus leading to resurgence. With fewer than 12 000 cases of this disabling and fatal disease reported per year, trypanosomiasis belongs to the most neglected tropical diseases. The clinical presentation is complex, and diagnosis and treatment difficult. The available drugs are old, complicated to administer, and can cause severe adverse reactions. New diagnostic methods and safe and effective drugs are urgently needed. Vector control, to reduce the number of flies in existing foci, needs to be organised on a pan-African basis. WHO has stated that if national control programmes, international organisations, research institutes, and philanthropic partners engage in concerted action, elimination of this disease might even be possible
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