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        검색결과 273

        22.
        2018.10 구독 인증기관·개인회원 무료
        Many insects are able to feed on crucifers despite the presence of a potent activated defense system known as the mustard oil bomb. In damaged tissue, mustard oil glucosides (glucosinolates) are hydrolyzed by the enzyme myrosinase to form toxic mustard oils (isothiocyanates). Here, we analyzed how the the cabbage stem flea beetle Psylliodes chrysocephala, a key pest of oilseed rape, copes with this chemical defense. First, we found that P. chrysocephala prevents the activation of ingested glucosinolates by two different strategies, a) by sequestering glucosinolates and b) by converting glucosinolates to desulfo-glucosinolates. Our next aim was to identify the sulfatase enzyme(s) responsible for the detoxification of glucosinolates in P. chrysocephala. Nine arylsulfatase-like genes were identified in the transcriptome of P. chrysocephala, and five of them showed glucosinolate sulfatase activity upon heterologous expression in Sf9 cells. By using RNAi, we confirmed that PcGSS1 and PcGSS2 are active towards benzenic and indolic glucosinolates in P. chrysocephala adults in vivo. However, in feeding experiments, the proportion of sequestered and desulfated glucosinolates ranged from 26 to 35% which suggests that these strategies alone are likely not sufficient to overcome the chemical plant defense. Indeed, P. chrysocephala additionally conjugates isothiocyanates to glutathione and metabolizes them via the conserved mercapturic acid pathway. In summary, the cabbage stem flea beetle avoids isothiocyanate formation by specialized strategies (sequestration and desulfation), but also relies on a conserved detoxification pathway to prevent toxicity of isothiocyanates.
        23.
        2018.07 구독 인증기관·개인회원 무료
        The major paradox in research in marketing: Can the researcher construct models that capture firm heterogeneities and achieve accurate prediction of outcomes for individual cases that also are generalizable across all the cases in the sample? This study presents a way forward for solving the major paradox. The study identifies research advances in theory and analytics that contribute successfully to the primary need to fill to achieve scientific legitimacy: Configurations that include accurate description, explanation, and prediction (i.e., predicting outcomes accurately of cases in samples separate from the samples of cases used to construct models having high fit validity.) The solution here includes philosophical, theoretical, and operational shifts away from variable-based modeling and null hypothesis statistical testing (NHST) to case-based modeling and somewhat precise outcome testing (SPOT). The study here provides examples of research contributing to knowledge and theory that advance prediction and control in business-to-business contexts. Shifting beyond linear model construction and symmetric tests (i.e., multiple regression analysis (MRA) and structural equation modeling (SEM)) and embracing complexity theory and asymmetric tests (i.e., constructing and testing algorithms by “computing with words,” Zadeh, (1996, 2010)) includes taking necessary steps away from examining “net effects” of variables to useful screening modeling of case configurations. Researchers embracing this shift in marketing benefit from recognizing that the current dominant logic of performing null hypothesis testing (NHST via MRA and SEM) is “corrupt research” (Hubbard, 2015) and from recognizing that predicting by algorithms via somewhat precise outcome testing (SPOT) advances business-to-business research toward achieving scientific legitimacy.
        24.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This manuscript explains the effective determination of urea by redox cyclic voltammetric analysis, for which a modified polypyrrole-graphene oxide (PPY-GO, GO 20% w/w of PPY) nanocomposite electrode was developed. Cyclic voltammetry measurements revealed an effective electron transfer in 0.1 M KOH electrolytic solution in the potential window range of 0 to 0.6 V. This PPY-GO modified electrode exhibited a moderate electrocatalytic effect towards urea oxidation, thereby allowing its determination in an electrolytic solution. The linear dependence of the current vs. urea concentration was reached using square-wave voltammetry in the concentration range of urea between 0.5 to 3.0 μM with a relatively low limit of detection of 0.27 μM. The scanning electron microscopy was used to characterize the morphologies and properties of the nanocomposite layer, along with Fourier transform infrared spectroscopy. The results indicated that the nanocomposite film modified electrode exhibited a synergistic effect, including high conductivity, a fast electron-transfer rate, and an inherent catalytic ability.
        4,000원
        33.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We report a spatial uctuation analysis of the sky brightness in the near-infrared from observations towards the north ecliptic pole (NEP) by AKARI at 2.4 and 3.2 μm. As a follow up study of our previous work on the Monitor eld of AKARI, we used NEP deep survey data, which covered a circular area of about 0.4 square degrees, in order to extend uctuation analysis at angular scales up to 1000". After pre-processing, additional correction procedures were done to correct time varying components and instrumental effects such as MUXbleed. To remove resolved objects, we applied 2α clipping and point spread function (PSF) subtraction. We finally obtained mosaicked images which can be used for the study of various diffuse emissions in the near-infrared sky and found that there are spatial structures in the mosaicked images using a power spectrum analysis.
        3,000원
        34.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        How does the presence of an AGN in uence the total SFR estimates of galaxies and change their distribution with respect to the Galaxy Main Sequence? To contribute to solving this question, we study a sample of 1133 sources detected in the North Ecliptic Pole field (NEP) by AKARI and Herschel. We create a multi-wavelength dataset for these galaxies and we fit their multi-wavelength Spectral Energy Distribution (SED) using the whole spectral regime (from 0.1 to 500 μm). We perform the fit using three procedures: LePhare and two optimised codes for identifying AGN tracers from the SED analysis. In this work we present an overview of the comparison between the estimates of the Infrared bolometric luminosi- ties (between 8 and 1000 μm) and the AGN fractions obtained exploiting these di erent procedures. In particular, by estimating the AGN contribution in four different wavelength ranges (5-40 μm, 10-20 μm, 20-40 μm and 8-1000 μm) we show how the presence of an AGN affects the PAH emission by suppressing the ratio L8 μm L4:5 μm as a function of the considered wavelength range.
        4,000원
        35.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The recent updates of the North Ecliptic Pole deep (0.5 deg2, NEP-Deep) multi-wavelength survey covering from X-ray to radio-wave is presented. The NEP-Deep provides us with several thousands of 15 μm or 18 μm selected galaxies, which is the largest sample ever made at these wavelengths. A continuous filter coverage in the mid-infrared wavelength (7, 9, 11, 15, 18, and 24 μm) is unique and vital to diagnose the contributions from starbursts and AGNs in the galaxies out to z=2. The new goal of the project is to resolve the nature of the cosmic star formation history at the violent epoch (e.g. z=1{2), and to find a clue to understand its decline from z=1 to present universe by utilizing the unique power of the multiwavelength survey. The progress in this context is brie y mentioned.
        4,000원
        38.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is imperious to know the reproductive parameters of the subsisting swine breed for profitable farming in Bangladesh. This study was designed to compare the reproductive parameters of sows at hilly areas between the local and crossbred at farm and backyard level. A total of 116 breedable sows were included. The data on age at puberty, litter size, birth weight, weaning weight, gestation length, interval between farrowing and number of piglets born per sow in local and crossbred sows were determined and direct questionnaire method was used for data collection. The present study revealed that age at puberty between farm and backyard system of crossbred sows was 8.88±0.153 and 9.85±0.221 months, respectively. The farrowing interval was shorter in crossbred sows which were kept in farming system rather than backyard system. The interval between farrowing and onset of estrus was shorter in crossbred sows. The gestation length was almost similar between backyard and farm condition. The number of litter size per sow per farrowing was 8.45±0.41 in crossbred and 7.17±0.250 in local pigs at backyard system. The birth weight and weaning weight were more in farm conditions than backyard system. The age at puberty in local breed was lower than the crossbred and litter size was 8.45±0.407 in crossbred which was higher than local breed 7.17±0.250 in backyard system. These results suggest that reproductive parameters of local sow need to be improved for better production and crossbred sows should be reared for obtaining desired productivity.
        4,000원
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