46 research outputs found

    Timing of embryonic quiescence determines viability of embryos from the calanoid copepod, Acartia tonsa (Dana)

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    <div><p>Like 41 other calanoid copepods, <i>Acartia tonsa</i>, are capable of inducing embryonic quiescence when experiencing unfavorable environmental conditions. The ecdysone-signaling cascade is known to have a key function in developmental processes like embryogenesis and molting of arthropods, including copepods. We examined the role of <i>ecdysteroid-phosphate phosphatase</i> (<i>EPPase</i>), <i>ecdysone receptor</i> (<i>EcR</i>), <i>ß fushi tarazu transcription factor 1</i> (<i>ßFTZ-F1</i>), and the <i>ecdysteroid-regulated early gene E74</i> (<i>E74</i>), which represent different levels of the ecdysone-signaling cascade in our calanoid model organism. Progression of embryogenesis was monitored and hatching success determined to evaluate viability. Embryos that were induced quiescence before the gastrulation stage would stay in gastrulation during the rest of quiescence and exhibited a slower pace of hatching as compared to subitaneous embryos. In contrast, embryos developed further than gastrulation would stay in gastrulation or later stages during quiescence and showed a rapid pace in hatching after quiescence termination. Expression patterns suggested two peaks of the biological active ecdysteroids, 20-hydroxyecdysone (20E). The first peak of 20E was expressed in concert with the beginning of embryogenesis originating from yolk-conjugated ecdysteroids, based on <i>EPPase</i> expression. The second peak is suggested to originate from <i>de novo</i> synthesized 20E around the limb bud stage. During quiescence, the expression patterns of <i>EPPase</i>, <i>EcR</i>, <i>ßFTZ-F1</i>, and <i>E74</i> were either decreasing or not changing over time. This suggests that the ecdysone-signaling pathway play a key role in the subitaneous development of <i>A</i>. <i>tonsa</i> embryogenesis, but not during quiescence. The observation is of profound ecological and practical relevance for the dynamics of egg banks.</p></div

    Electrophysiological evidence for an early processing of human voices

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    <p>Abstract</p> <p>Background</p> <p>Previous electrophysiological studies have identified a "voice specific response" (VSR) peaking around 320 ms after stimulus onset, a latency markedly longer than the 70 ms needed to discriminate living from non-living sound sources and the 150 ms to 200 ms needed for the processing of voice paralinguistic qualities. In the present study, we investigated whether an early electrophysiological difference between voice and non-voice stimuli could be observed.</p> <p>Results</p> <p>ERPs were recorded from 32 healthy volunteers who listened to 200 ms long stimuli from three sound categories - voices, bird songs and environmental sounds - whilst performing a pure-tone detection task. ERP analyses revealed voice/non-voice amplitude differences emerging as early as 164 ms post stimulus onset and peaking around 200 ms on fronto-temporal (positivity) and occipital (negativity) electrodes.</p> <p>Conclusion</p> <p>Our electrophysiological results suggest a rapid brain discrimination of sounds of voice, termed the "fronto-temporal positivity to voices" (FTPV), at latencies comparable to the well-known face-preferential N170.</p

    Predictive modelling of soils’ hydraulic conductivity using artificial neural network and multiple linear regression

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    As a result of heterogeneity nature of soils and variation in its hydraulic conductivity over several orders of magnitude for various soil types from fine-grained to coarse-grained soils, predictive methods to estimate hydraulic conductivity of soils from properties considered more easily obtainable have now been given an appropriate consideration. This study evaluates the performance of artificial neural network (ANN) being one of the popular computational intelligence techniques in predicting hydraulic conductivity of wide range of soil types and compared with the traditional multiple linear regression (MLR). ANN and MLR models were developed using six input variables. Results revealed that only three input variables were statistically significant in MLR model development. Performance evaluations of the developed models using determination coefficient and mean square error show that the prediction capability of ANN is far better than MLR. In addition, comparative study with available existing models shows that the developed ANN and MLR in this study performed relatively better

    Pathologic characteristics of breast cancer with special emphasis on prevalence of triple-negative breast cancer from Kenya: A 4-year experience.

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    Background: Previous sub classification of breast cancer in Kenya has been fraught by small sample size, non uniform staining methodology and lack of independent review. Triple Negative Breast Cancer (TNBC) is a “special interest” cancer since it represents a significant proportion of breast cancer patients and is associated with a poorer prognosis. We aimed to determine the estrogen receptor (ER), progesterone receptor (PR) and Her2/neu receptor characteristics of breast cancers and the prevalence of TNBC diagnosed at Aga Khan University Hospital, Nairobi (AKUHN) between 2007 to date. Methods: Slides and blocks of archived invasive breast cancers diagnosed at AKUHN were identified, retrieved and reviewed by two independent pathologists. Histological type, grade and pathological stage were documented. Representative sections from available blocks were stained for ER, PR, Her2 with appropriate internal controls. Scores for ER/PR were interpreted based on the ALLRED system, Her2 /neu scoring followed CAP guidelines. The initial 111 cases were validated and confirmed at Sunnybrook Health Sciences Centre, Toronto. Results: 456 cases of invasive breast cancers were diagnosed at AKUHN during the study period. 91% of cases were invasive ductal carcinomas (NOS).The rest were special types. 37% of the tumors were grade 3 and 63% were grade 2. Blocks for 318 of 456 cases were available for receptor analysis. 54% were ER and/or PR positive, with 52% of these in women \u3c 50 yrs. 86% of the ER and/or PR positive tumors were grade 2. Only 12% were Her2/neu positive. Of the 318 cases studied, 111 (32%) were identified as TNBC. Median age was 53 yrs. 88% were grade 3. Conclusions: Invasive ductal carcinoma (NOS) was the most common breast cancer in our study. Nearly half of our cases were ER and/or PR positive and a third were TNBC. Both occurred predominantly in women less than 50 yrs. This represents the largest validated pathologic sub classification of breast cancer from a tertiary academic hospital in Kenya. Expansion of this study to encompass all breast cancers diagnosed in Kenya is underway

    Five novel loci for inherited hearing loss mapped by SNP-based homozygosity profiles in Palestinian families

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    In communities with high rates of consanguinity and consequently high prevalence of recessive phenotypes, homozygosity mapping with SNP arrays is an effective approach for gene discovery. In 20 Palestinian kindreds with prelingual nonsyndromic hearing loss, we generated homozygosity profiles reflecting linkage to the phenotype. Family sizes ranged from small nuclear families with two affected children, one unaffected sibling, and parents to multigenerational kindreds with 12 affected relatives. By including unaffected parents and siblings and screening 250 K SNP arrays, even small nuclear families yielded informative profiles. In 14 families, we identified the allele responsible for hearing loss by screening a single candidate gene in the longest homozygous region. Novel alleles included missense, nonsense, and splice site mutations of CDH23, MYO7A, MYO15A, OTOF, PJVK, Pendrin/SLC26A4, TECTA, TMHS, and TMPRSS3, and a large genomic deletion of Otoancorin (OTOA). All point mutations were rare in the Palestinian population (zero carriers in 288 unrelated controls); the carrier frequency of the OTOA genomic deletion was 1%. In six families, we identified five genomic regions likely to harbor novel genes for human hearing loss on chromosomes 1p13.3 (DFNB82), 9p23–p21.2/p13.3–q21.13 (DFNB83), 12q14.3–q21.2 (DFNB84; two families), 14q23.1–q31.1, and 17p12–q11.2 (DFNB85)

    Tools implementation in management of continuous improvement processes

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    Technological development and pressure to meet customer requirements through high productivity and low costs forces companies to be extremely flexible and efficient. For this purpose, many organizations have been adopting continuous improvement strategy which promotes constant insertion of small incremental improvements and better results in regard of efficiency and quality. The aim of this paper is to show how a company has progressed its continuous improvement of management processes. This was successfully achieved through new tools developed to solve different problems in distinct dimensions regarding continuous improvement. The developed tools were database systems and it was possible to realise their positive impact in continuous improvement of management processes in the focused company were they were implemented, since they established access to consistent data and did enable to reduce redundant information spread across multiple files and software tools, and thus eliminating waste. Moreover, these new tools developed allowed to pass from traditional and manual recorded methods to computerized systems, making information more accessible and always updated. Thus connection between information systems and management of continuous improvement processes is essential for companies’ evolution and success.This work has been supported by FCT Fundação para a CiĂȘncia e Tecnologia, under the Project: PEst2015-202
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