ARGONAUTE PIWI domain and microRNA duplex structure regulate small RNA sorting in Arabidopsis.

Small RNAs (sRNAs) are loaded into ARGONAUTE (AGO) proteins to induce gene silencing. In plants, the 5'-terminal nucleotide is important for sRNA sorting into different AGOs. Here we show that microRNA (miRNA) duplex structure also contributes to miRNA sorting. Base pairing at the 15th nucleotide of a miRNA duplex is important for miRNA sorting in both Arabidopsis AGO1 and AGO2. AGO2 favours miRNA duplexes with no middle mismatches, whereas AGO1 tolerates, or prefers, duplexes with central mismatches. AGO structure modelling and mutational analyses reveal that the QF-V motif within the conserved PIWI domain contributes to recognition of base pairing at the 15th nucleotide of a duplex, while the DDDE catalytic core of AtAGO2 is important for recognition of the central nucleotides. Finally, we rescued the adaxialized phenotype of ago1-12, which is largely due to miR165 loss-of-function, by changing miR165 duplex structure which we predict redirects it to AGO2

Time-resolved propagation of polarized light in turbid media: experiment and theory

This paper presents our study of time-resolved propagation of polarized light in scattering media. Monte Carlo simulated time-resolved Stokes vectors of transmitted light were compared with the experimental results. A satisfying match has been obtained

PT Symmetry as a Generalization of Hermiticity

The Hilbert space in PT-symmetric quantum mechanics is formulated as a linear vector space with a dynamic inner product. The most general PT-symmetric matrix Hamiltonians are constructed for 2*2 and 3*3 cases. In the former case, the PT-symmetric Hamiltonian represents the most general matrix Hamiltonian with a real spectrum. In both cases, Hermitian matrices are shown to be special cases of PT-symmetric matrices. This finding confirms and strengthens the early belief that the PT-symmetric quantum mechanics is a generalization of the conventional Hermitian quantum mechanics.Comment: 13 page

An Econometric Analysis of ETF and ETF Futures in Financial and Energy Markets Using Generated Regressors

It is well known that that there is an intrinsic link between the financial and energy sectors, which can be analyzed through their spillover effects, which are measures of how the shocks to returns in different assets affect each other’s subsequent volatility in both spot and futures markets. Financial derivatives, which are not only highly representative of the underlying indices but can also be traded on both the spot and futures markets, include Exchange Traded Funds (ETFs), which is a tradable spot index whose aim is to replicate the return of an underlying benchmark index. When ETF futures are not available to examine spillover effects, “generated regressors” may be used to construct both Financial ETF futures and Energy ETF futures. The purpose of the paper is to investigate the co-volatility spillovers within and across the US energy and financial sectors in both spot and futures markets, by using “generated regressors” and a multivariate conditional volatility model, namely Diagonal BEKK. The daily data used are from 1998/12/23 to 2016/4/22. The data set is analyzed in its entirety, and also subdivided into three subset time periods. The empirical results show there is a significant relationship between the Financial ETF and Energy ETF in the spot and futures markets. Therefore, financial and energy ETFs are suitable for constructing a financial portfolio from an optimal risk management perspective, and also for dynamic hedging purposes

Testing Co-Volatility Spillovers for Natural Gas Spot, Futures and ETF Spot using Dynamic Conditional Covariances

There is substantial empirical evidence that energy and financial markets are closely connected. As one of the most widely-used energy resources worldwide, natural gas has a large daily trading volume. In order to hedge the risk of natural gas spot markets, a large number of hedging strategies can be used, especially with the rapid development of natural gas derivatives markets. These hedging instruments include natural gas futures and options, as well as Exchange Traded Fund (ETF) prices that are related to natural gas stock prices. The volatility spillover effect is the delayed effect of a returns shock in one physical, biological or financial asset on the subsequent volatility or co-volatility of another physical, biological or financial asset. Investigating volatility spillovers within and across energy and financial markets is a crucial aspect of constructing optimal dynamic hedging strategies. The paper tests and calculates spillover effects among natural gas spot, futures and ETF markets using the multivariate conditional volatility diagonal BEKK model. The data used include natural gas spot and futures returns data from two major international natural gas derivatives markets, namely NYMEX (USA) and ICE (UK), as well as ETF data of natural gas companies from the stock markets in the USA and UK. The empirical results show that there are significant spillover effects in natural gas spot, futures and ETF markets for both USA and UK. Such a result suggests that both natural gas futures and ETF products within and beyond the country might be considered when constructing optimal dynamic hedging strategies for natural gas spot prices

Trogodišnji trend promjena tjelesne pripremljenosti i indeksa tjelesne mase u učenika u dobi od 12 do 16 godina s ekstremnim indeksima tjelesne mase

The aim of this study was to investigate a three-year development in BMI and physical fitness of schoolchildren aged 12-16 years with extreme weight status. Taiwan Physical Fitness Test Battery, assessing aerobic fitness (1600-meter walk/run test), power (standing long jump), muscular endurance (sit-up), and flexibility (sit-and-reach) in 16,945 boys, was implemented in September from the year 2006 till 2008. Overweight and underweight were defined by the baseline BMI data values that fall within the highest and lowest 5% of their age population, whereas the BMI data values that fall within one standard deviation of the mean was considered “normal” in this study. The results showed that BMI of schoolchildren in 2006 was ~2–3 kg/m2 above the national average reported in 1993. All physical fitness components in the overweight group were substantially poorer than those in the normal group. Yet, these fitness parameters were improved over the three years in all groups. BMI in the underweight group increased at a faster rate than that in the normal and overweight groups. No difference was found in the jumping distance between the underweight and normal groups. Aerobic fitness in the underweight group was superior but flexibility and muscular endurance were slightly lower than those in the normal group. BMI of Taiwan schoolchildren increased substantially from 1993 to 2006 but leveled off from 2006 to 2008. Underweight schoolchildren during the growing period should not a priori be considered as physically weaker or unfit individuals.Cilj je ovog istraživanja bio ustanoviti trogodišnji trend razvoja indeksa tjelesne mase (ITM) i tjelesne pripremljenosti u učenika, u dobi između 12 i 16 godina, s ekstremnim vrijednostima tjelesne težine. Tajvanski sklop testova za tjelesnu pripremljenosti (Taiwan Physical Fitness Test Battery), koja uključuje procjenu aerobne pripremljenosti (test hodanja/ trčanja na 1600 metara), eksplozivne snage (skok u dalj s mjesta), mišićne izdržljivosti (podizanje trupa iz ležanja na leđima) i fleksibilnosti (sjed-i-dohvat), primijenjen je od 2006 do 2008 godine u mjesecu rujnu na uzorku od 16.945 dječaka. Preteški (overweight) i prelagani (underweight) ispitanici bili su definirani prema inicijalnoj vrijednosti ITM-a za dobnu skupinu populacije ispitanika kao oni koji se ubrajaju među 5% s najvišim odnosno najnižim vrijednostima ITM. Ispitanici koji su se nalazili unutar jedne standardne devijacije smatrali su se „normalnima“. Rezultati su pokazali da je ITM tajvanskih učenika u 2006. godini bio za ~2–3kg/m2 veći od nacionalnog prosjeka objavljenog 1993. godine. Sve varijable tjelesne pripremljenosti u grupi prekomjerno teških bile su značajno lošije u odnosu na rezultate koje su postigli ispitanici u normalnoj grupi. Ipak, rezultati su se u svim mjerenim varijablama u svim grupama poboljšali tijekom 3 godine mjerenja. ITM je u grupi nedovoljno teških porastao većom brzinom nego u grupama normalnih i prekomjerno teških učenika. Nije utvrđena značajna razlika u rezultatima skoka u dalj s mjesta između grupa nedovoljno teških i normalnih ispitanika. Nedovoljno teški ispitanici imali su najbolje rezultate u aerobnoj izdržljivosti u odnosu na ostale grupe, dok su u fleksibilnosti i mišićnoj izdržljivosti bili nešto slabiji nego ispitanici u normalnoj grupi. ITM je u tajvanske djece značajno porastao u razdoblju od 1993. do 2006. godine, ali je i stagnirao u razdoblju od 2006. do 2008. godine. Nedovoljno teška djeca ne bi se smjela a priori smatrati fizički slabijom ili nespremnom tijekom perioda odrastanja

Modelling Volatility Spillovers for Bio-ethanol, Sugarcane and Corn Spot and Futures Prices

The recent and rapidly growing interest in biofuel as a green energy source has raised concerns about its impact on the prices, returns and volatility of related agricultural commodities. Analyzing the spillover effects on agricultural commodities and biofuel helps commodity suppliers hedge their portfolios, and manage the risk and co-risk of their biofuel and agricultural commodities. There have been many papers concerned with analyzing crude oil and agricultural commodities separately. The purpose of this paper is to examine the volatility spillovers for spot and futures returns on bio-ethanol and related agricultural commodities, specifically corn and sugarcane. The diagonal BEKK model is used as it is the only multivariate conditional volatility model with well-established regularity conditions and known asymptotic properties. The daily data used are from 31 October 2005 to 14 January 2015. The empirical results show that, in 2 of 6 cases for the spot market, there were significant negative co-volatility spillover effects: specifically, corn on subsequent sugarcane co-volatility with corn, and sugarcane on subsequent corn co-volatility with sugarcane. In the other 4 cases, there are no significant co-volatility spillover effects. There are significant positive co-volatility spillover effects in all 6 cases, namely between corn and sugarcane, corn and ethanol, and sugarcane and ethanol, and vice-versa, for each of the three pairs of commodities. It is clear that the futures prices of bio-ethanol and the two agricultural commodities, corn and sugarcane, have stronger co-volatility spillovers than their spot price counterparts. These empirical results suggest that the bio-ethanol and agricultural commodities should be considered as viable futures products in financial portfolios for risk managemen

Polarization-gated imaging techniques based on time-resolved Stokes vectors for filament tissues

We report the discovery of using various time-resolved Stokes vector components for more efficient imaging of filament tissues. In particular, the Stokes vector components S2 and S3 were found more useful, compared with the other two components. The time-resolved Stokes vectors of signals transmitting chicken breast tissue, mouse cardiac muscle tissue, and polystyrene micro-sphere solution are compared. A target of chicken bone in chicken breast tissue is used for demonstrating the effectiveness of various Stokes vector components for imaging purpose. Also, Monte Carlo simulations were conducted for comparison