358 research outputs found

    Hatchery production of Black-lip pearl oyster spat in the Andaman and Nicobar Islands: a success story

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    The lustrous black pearls produced by the black-lip pearl oysler Pinctada margaritifera in the inner surface its two shells have become one of the most valuable pearls on earth with prices ranging from a minimum of 100 USandtoamaximumof10,000US and to a maximum of 10,000 US per pearl, in the case of those at exceptional and rare quality. Through the production of black pearls from Pinctada margaritifera, the island country of Tahili became the global leader in this business controlling 28.8% of the world market

    Biometric relationships of the black winged pearl oyster, Pteria penguin (Roding, 1798) from Andaman and Nicobar Islands

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    The dimensional biometric relationships including that of length-weight was studied in the black winged oyster Pteria penguin, which is a candidate species for mariculture. During the life span of the winged oysters, growth in length and weight was initially 40-100 mm dorso-ventral measurement (DVM), positively allometric and subsequently became isometric (100-160 mm DVM) and finally reverted back to allometry (160-220 mm DVM). This is attributed to the increase in visceral mass of animals corresponding to gonadal maturation during the size range 100 - 160 mm DVM. In larger sized P. penguin, increase in shell length is more predominant as evidenced by large proportion of non-nacreous layer at the outer edge of the shell. There was no parallel increase in visceral mass resulting in allometry. All dimensional relationships were positive in relation to DVM; however the relationship between DVM and hinge length did not show significant R2 values (p>0.05) in all the size groups. This was mainly because, the tips of the hinge and ear were found to be broken at both the ends. Therefore, notch length is proposed as a better predictor of DVM in large hinged pterid oysters. Unlike other pterid pearl oysters, the thickness - DVM ratio showed a decline with size, indicating that bead seeding programmes can be initiated at early stage

    Biometric relationships of the black-lip pearl oyster Pinctada margaritifera (Linnaeus, 1758) from the Andaman and Nicobar waters

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    The black-lip pearl oyster, Pinctada margaritifera is widely distributed in Indo-Pacific region and has prime importance in the production of black pearls. In India, its natural occurrence is confined to the Andaman and Nicobar Islands. The biometric relationships between (dorso-ventral measurement [DVM] and Hinge Length [HL]; Thickness [THK] and Total Weight [TWT]) were studied from 458 oysters collected from these islands which were grouped in to 5 length classes. In all size groups, there was increase in weight with increase in length. The highest coefficient (r2=0.7828) was obtained for the animals with DVM ranging from 76 to 95 mm. The correlation coefficient ‘r’ was low for DVM-HL and slightly higher for DVM-THK. Comparisons of biometric relationships of the natural populations of the Indian pearl oysters with that of farmed oysters in other regions indicated xenomorphism in pearl oysters in Andaman and Nicobar Islands due to restricted space in natural habitats

    Interferon regulatory factor 8-deficiency determines massive neutrophil recruitment but T cell defect in fast growing granulomas during tuberculosis

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    Following Mycobacterium tuberculosis (Mtb) infection, immune cell recruitment in lungs is pivotal in establishing protective immunity through granuloma formation and neogenesis of lymphoid structures (LS). Interferon regulatory factor-8 (IRF-8) plays an important role in host defense against Mtb, although the mechanisms driving anti-mycobacterial immunity remain unclear. In this study, IRF-8 deficient mice (IRF-8−/−) were aerogenously infected with a low-dose Mtb Erdman virulent strain and the course of infection was compared with that induced in wild-type (WT-B6) counterparts. Tuberculosis (TB) progression was examined in both groups using pathological, microbiological and immunological parameters. Following Mtb exposure, the bacterial load in lungs and spleens progressed comparably in the two groups for two weeks, after which IRF-8−/− mice developed a fatal acute TB whereas in WT-B6 the disease reached a chronic stage. In lungs of IRF-8−/−, uncontrolled growth of pulmonary granulomas and impaired development of LS were observed, associated with unbalanced homeostatic chemokines, progressive loss of infiltrating T lymphocytes and massive prevalence of neutrophils at late infection stages. Our data define IRF-8 as an essential factor for the maintenance of proper immune cell recruitment in granulomas and LS required to restrain Mtb infection. Moreover, IRF-8−/− mice, relying on a common human and mouse genetic mutation linked to susceptibility/severity of mycobacterial diseases, represent a valuable model of acute TB for comparative studies with chronically-infected congenic WT-B6 for dissecting protective and pathological immune reactions

    A survey of the state-of-the-art techniques for cognitive impairment detection in the elderly

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    With a growing number of elderly people in the UK, more and more of them suffer from various kinds of cognitive impairment. Cognitive impairment can be divided into different stages such as mild cognitive impairment (MCI) and severe cognitive impairment like dementia. Its early detection can be of great importance. However, it is challenging to detect cognitive impairment in the early stage with high accuracy and low cost, when most of the symptoms may not be fully expressed. This survey paper mainly reviews the state of the art techniques for the early detection of cognitive impairment and compares their advantages and weaknesses. In order to build an effective and low-cost automatic system for detecting and monitoring the cognitive impairment for a wide range of elderly people, the applications of computer vision techniques for the early detection of cognitive impairment by monitoring facial expressions, body movements and eye movements are highlighted in this paper. In additional to technique review, the main research challenges for the early detection of cognitive impairment with high accuracy and low cost are analysed in depth. Through carefully comparing and contrasting the currently popular techniques for their advantages and weaknesses, some important research directions are particularly pointed out and highlighted from the viewpoints of the authors alone

    Brain multiplexes reveal morphological connectional biomarkers fingerprinting late brain dementia states

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    Accurate diagnosis of mild cognitive impairment (MCI) before conversion to Alzheimer\u27s disease (AD) is invaluable for patient treatment. Many works showed that MCI and AD affect functional and structural connections between brain regions as well as the shape of cortical regions. However, \u27shape connections\u27 between brain regions are rarely investigated -e.g., how morphological attributes such as cortical thickness and sulcal depth of a specific brain region change in relation to morphological attributes in other regions. To fill this gap, we unprecedentedly design morphological brain multiplexes for late MCI/AD classification. Specifically, we use structural T1-w MRI to define morphological brain networks, each quantifying similarity in morphology between different cortical regions for a specific cortical attribute. Then, we define a brain multiplex where each intra-layer represents the morphological connectivity network of a specific cortical attribute, and each inter-layer encodes the similarity between two consecutive intra-layers. A significant performance gain is achieved when using the multiplex architecture in comparison to other conventional network analysis architectures. We also leverage this architecture to discover morphological connectional biomarkers fingerprinting the difference between late MCI and AD stages, which included the right entorhinal cortex and right caudal middle frontal gyrus

    Assessing the health benefits of development interventions

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    Biomedical interventions, such as therapeutics, vaccines and insecticides, are alone insufficient to achieve Sustainable Development Goal (SDG) 3—healthy lives and wellbeing for all ages. We also need development interventions to tackle the underlying determinants of ill-health by reducing deprivation and improving living conditions and the environment. This recognition formed the bedrock of early public health, from housing improvements and clean water provision in 19th century Europe and North America, to house screening for malaria elimination in the USA and water management for historical vector control in Italy, Sri Lanka, Panama and Zambia. Today, development interventions are a basic human right and ever more critical in response to rapid population growth, urbanisation and climate change

    Replication, Neurotropism, and Pathogenicity of Avian Paramyxovirus Serotypes 1–9 in Chickens and Ducks

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    Avian paramyxovirus (APMV) serotypes 1–9 have been isolated from many different avian species. APMV-1 (Newcastle disease virus) is the only well-characterized serotype, because of the high morbidity, mortality, and economic loss caused by highly virulent strains. Very little is known about the pathogenesis, replication, virulence, and tropism of the other APMV serotypes. Here, this was evaluated for prototypes strains of APMV serotypes 2–9 in cell culture and in chickens and ducks. In cell culture, only APMV-1, -3 and -5 induced syncytium formation. In chicken DF1 cells, APMV-3 replicated with an efficiency approaching that of APMV-1, while APMV-2 and -5 replicated to lower, intermediate titers and the others were much lower. Mean death time (MDT) assay in chicken eggs and intracerebral pathogenicity index (ICPI) test in 1-day-old SPF chicks demonstrated that APMV types 2–9 were avirulent. Evaluation of replication in primary neuronal cells in vitro as well as in the brains of 1-day-old chicks showed that, among types 2–9, only APMV-3 was neurotropic, although this virus was not neurovirulent. Following intranasal infection of 1-day-old and 2-week-old chickens, replication of APMV types 2–9 was mostly restricted to the respiratory tract, although APMV-3 was neuroinvasive and neurotropic (but not neurovirulent) and also was found in the spleen. Experimental intranasal infection of 3-week-old mallard ducks with the APMVs did not produce any clinical signs (even for APMV-1) and exhibited restricted viral replication of the APMVs (including APMV-1) to the upper respiratory tract regardless of their isolation source, indicating avirulence of APMV types 1–9 in mallard ducks. The link between the presence of a furin cleavage site in the F protein, syncytium formation, systemic spread, and virulence that has been well-established with APMV-1 pathotypes was not evident with the other APMV serotypes

    Association of acute toxic encephalopathy with litchi consumption in an outbreak in Muzaffarpur, India, 2014: a case-control study

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    Background Outbreaks of unexplained illness frequently remain under-investigated. In India, outbreaks of an acute neurological illness with high mortality among children occur annually in Muzaffarpur, the country’s largest litchi cultivation region. In 2014, we aimed to investigate the cause and risk factors for this illness. Methods In this hospital-based surveillance and nested age-matched case-control study, we did laboratory investigations to assess potential infectious and non-infectious causes of this acute neurological illness. Cases were children aged 15 years or younger who were admitted to two hospitals in Muzaffarpur with new-onset seizures or altered sensorium. Age-matched controls were residents of Muzaffarpur who were admitted to the same two hospitals for a non-neurologic illness within seven days of the date of admission of the case. Clinical specimens (blood, cerebrospinal fluid, and urine) and environmental specimens (litchis) were tested for evidence of infectious pathogens, pesticides, toxic metals, and other non-infectious causes, including presence of hypoglycin A or methylenecyclopropylglycine (MCPG), naturally-occurring fruit-based toxins that cause hypoglycaemia and metabolic derangement. Matched and unmatched (controlling for age) bivariate analyses were done and risk factors for illness were expressed as matched odds ratios and odds ratios (unmatched analyses). Findings Between May 26, and July 17, 2014, 390 patients meeting the case definition were admitted to the two referral hospitals in Muzaffarpur, of whom 122 (31%) died. On admission, 204 (62%) of 327 had blood glucose concentration of 70 mg/dL or less. 104 cases were compared with 104 age-matched hospital controls. Litchi consumption (matched odds ratio [mOR] 9·6 [95% CI 3·6 – 24]) and absence of an evening meal (2·2 [1·2–4·3]) in the 24 h preceding illness onset were associated with illness. The absence of an evening meal significantly modified the effect of eating litchis on illness (odds ratio [OR] 7·8 [95% CI 3·3–18·8], without evening meal; OR 3·6 [1·1–11·1] with an evening meal). Tests for infectious agents and pesticides were negative. Metabolites of hypoglycin A, MCPG, or both were detected in 48 [66%] of 73 urine specimens from case-patients and none from 15 controls; 72 (90%) of 80 case-patient specimens had abnormal plasma acylcarnitine profiles, consistent with severe disruption of fatty acid metabolism. In 36 litchi arils tested from Muzaffarpur, hypoglycin A concentrations ranged from 12·4 μg/g to 152·0 μg/g and MCPG ranged from 44·9 μg/g to 220·0 μg/g. Interpretation Our investigation suggests an outbreak of acute encephalopathy in Muzaffarpur associated with both hypoglycin A and MCPG toxicity. To prevent illness and reduce mortality in the region, we recommended minimising litchi consumption, ensuring receipt of an evening meal and implementing rapid glucose correction for suspected illness. A comprehensive investigative approach in Muzaffarpur led to timely public health recommendations, underscoring the importance of using systematic methods in other unexplained illness outbreaks
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