Heavy metals in paddy fields in Taiwan: chemical behavior in soil and uptake by brown rice

Levels of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) were measured in 19 individual paddy fields in Taiwan. Total, reactive, and available metal levels were measured using Aqua Regia, 0.43 N HNO3, 0.1 M HCl, 0.05 M EDTA and 0.01 M CaCl2. Total metal levels ranged from below background levels to polluted and were highly heterogeneous across most fields. In general levels of metals in the soil decreased with an increase in distance from the water inlet which suggests that most metals originate from the irrigation water. Availability as measured by 0.01 M CaCl2 could be predicted well (Cd, Ni, Zn) by a Freundlich model similar to the one used in non-tropical soils. The fit of models for Cu and Pb was poor due to the lack of data on dissolved organic carbon (DOC). For Cr no fit was obtained at all. Uptake of Cd by rice was highly correlated to the availability as measured by CaCl2. Uptake models based on either the CaCl2 extractable Cd and Zn in soil solution, or a combination of the reactive Cd content in combination with pH and CEC proved equally suitable to predict Cd in rice. The impact of pH and, to a lesser extent, CEC urges the need to considere both properties when deriving soil quality standards (SQS). Uptake by rice by Indica species was markedly higher than that of Japonica although uptake by roots proved to be similar between both species. This suggests that differences between Japonica and Indica are more related to internal redistribution rather than differences in root uptake processes. Using the models, user friendly tools are designed allowing farmers and policy makers alike to evaluate the quality of the soil for a specific cultivar. This allows for a more accurate assessment of the suitability of the soil to be used for rice cropping compared to present soil standards based on Aqua Regia or HCl. As such the approach can be transferred easily to other countries as well based on a limited number of field tests

Characterization of soil heavy metal pools in paddy fields in Taiwan: chemical extraction and solid-solution partitioning

Ongoing industrialization has resulted in an accumulation of metals like Cd, Cu, Cr, Ni, Zn, and Pb in paddy fields across Southeast Asia. Risks of metals in soils depend on soil properties and the availability of metals in soil. At present, however, limited information is available on how to measure or predict the directly available fraction of metals in paddy soils. Here, the distribution of Cd, Cu, Cr, Ni, Zn, and Pb in 19 paddy fields among the total, reactive, and directly available pools was measured using recently developed concepts for aerated soils. Solid-solution partitioning models have been derived to predict the directly available metal pool. Such models are proven to be useful for risk assessment and to derive soil quality standards for aerated soils. Soil samples (0-25 cm) were taken from 19 paddy fields from five different communities in Taiwan in 2005 and 2006. Each field was subdivided into 60 to 108 plots resulting in a database of approximately 3,200 individual soil samples. Total (Aqua Regia (AR)), reactive (0.43 M HNO3, 0.1 M HCl, and 0.05 M EDTA), and directly available metal pools (0.01 M CaCl2) were determined. Solid-solution partitioning models were derived by multiple linear regressions using an extended Freundlich equation using the reactive metal pool, pH, and the cation exchange capacity (CEC). The influence of Zn on metal partitioning and differences between both sampling events (May/November) were evaluated. Total metals contents range from background levels to levels in excess of current soil quality standards for arable land. Between 3% (Cr) and 30% (Cd) of all samples exceed present soil quality standards based on extraction with AR. Total metal levels decreased with an increasing distance from the irrigation water inlet. The reactive metal pool relative to the total metal content is increased in the order C

The environmental assessment of landfill based on stakeholder analysis

AbstractFor the current issue that harmful landfill caused serious harm but had passed the environmental assessment, the paper uses the stakeholder analysis theory to analyze the stakeholders of landfill, and find the reasons existed in environmental assessment of landfill based on the simple review of the development and application of stakeholder analysis. And then it gave the countermeasure to the improvement of environmental assessment index system of landfill and the perfection of environmental assessment mechanism

Improved Approximation Algorithms for Computing k Disjoint Paths Subject to Two Constraints

For a given graph $G$ with positive integral cost and delay on edges, distinct vertices $s$ and $t$, cost bound $C\in Z^{+}$ and delay bound $D\in Z^{+}$, the $k$ bi-constraint path ($k$BCP) problem is to compute $k$ disjoint $st$-paths subject to $C$ and $D$. This problem is known NP-hard, even when $k=1$ \cite{garey1979computers}. This paper first gives a simple approximation algorithm with factor-$(2,2)$, i.e. the algorithm computes a solution with delay and cost bounded by $2*D$ and $2*C$ respectively. Later, a novel improved approximation algorithm with ratio $(1+\beta,\,\max\{2,\,1+\ln\frac{1}{\beta}\})$ is developed by constructing interesting auxiliary graphs and employing the cycle cancellation method. As a consequence, we can obtain a factor-$(1.369,\,2)$ approximation algorithm by setting $1+\ln\frac{1}{\beta}=2$ and a factor-$(1.567,\,1.567)$ algorithm by setting $1+\beta=1+\ln\frac{1}{\beta}$. Besides, by setting $\beta=0$, an approximation algorithm with ratio $(1,\, O(\ln n))$, i.e. an algorithm with only a single factor ratio $O(\ln n)$ on cost, can be immediately obtained. To the best of our knowledge, this is the first non-trivial approximation algorithm for the $k$BCP problem that strictly obeys the delay constraint.Comment: 12 page

Hamiltonian Formalism of the de-Sitter Invariant Special Relativity

Lagrangian of the Einstein's special relativity with universal parameter $c$ ($\mathcal{SR}_c$) is invariant under Poincar\'e transformation which preserves Lorentz metric $\eta_{\mu\nu}$. The $\mathcal{SR}_c$ has been extended to be one which is invariant under de Sitter transformation that preserves so called Beltrami metric $B_{\mu\nu}$. There are two universal parameters $c$ and $R$ in this Special Relativity (denote it as $\mathcal{SR}_{cR}$). The Lagrangian-Hamiltonian formulism of $\mathcal{SR}_{cR}$ is formulated in this paper. The canonic energy, canonic momenta, and 10 Noether charges corresponding to the space-time's de Sitter symmetry are derived. The canonical quantization of the mechanics for $\mathcal{SR}_{cR}$-free particle is performed. The physics related to it is discussed.Comment: 24 pages, no figur

CMB Power Spectrum from Noncommutative Spacetime

Very recent CMB data of WMAP offers an opportunity to test inflation models, in particular, the running of spectral index is quite new and can be used to rule out some models. We show that an noncommutative spacetime inflation model gives a good explanation of these new results. In fitting the data, we also obtain a relationship between the noncommutative parameter (string scale) and the ending time of inflation.Comment: 8 pages, 2 figures; v2: refs. added and minor corrections; v3: further minor correctio

Interaction of the S6 Proline Hinge with N-Type and C-Type Inactivation in Kv1.4 Channels

AbstractSeveral voltage-gated channels share a proline-valine-proline (proline hinge) sequence motif at the intracellular side of S6. We studied the proline hinge in Kv1.4 channels, which inactivate via two mechanisms: N- and C-type. We mutated the second proline to glycine or alanine: P558A, P558G. These mutations were studied in the presence/absence of the N-terminal to separate the effects of the interaction between the proline hinge and N- and C-type inactivation. Both S6 mutations slowed or removed N- and C-type inactivation, and altered recovery from inactivation. P558G slowed activation and N- and C-type inactivation by nearly an order of magnitude. Sensitivity to extracellular acidosis and intracellular quinidine binding remained, suggesting that transmembrane communication in N- and C-type inactivation was preserved, consistent with our previous findings of major structural rearrangements involving S6 during C-type inactivation. P558A was very disruptive: activation was slowed by more than an order of magnitude, and no inactivation was observed. These results are consistent with our hypothesis that the proline hinge and intracellular S6 movement play a significant role in inactivation and recovery. Computer modeling suggests that both P558G and P558A mutations modify early voltage-dependent steps and make a final voltage-insensitive step that is rate limiting at positive potentials

Measure representation and multifractal analysis of complete genomes

This paper introduces the notion of measure representation of DNA sequences. Spectral analysis and multifractal analysis are then performed on the measure representations of a large number of complete genomes. The main aim of this paper is to discuss the multifractal property of the measure representation and the classification of bacteria. From the measure representations and the values of the $D_{q}$ spectra and related $C_{q}$ curves, it is concluded that these complete genomes are not random sequences. In fact, spectral analyses performed indicate that these measure representations considered as time series, exhibit strong long-range correlation. For substrings with length K=8, the $D_{q}$ spectra of all organisms studied are multifractal-like and sufficiently smooth for the $C_{q}$ curves to be meaningful. The $C_{q}$ curves of all bacteria resemble a classical phase transition at a critical point. But the 'analogous' phase transitions of chromosomes of non-bacteria organisms are different. Apart from Chromosome 1 of {\it C. elegans}, they exhibit the shape of double-peaked specific heat function.Comment: 12 pages with 9 figures and 1 tabl

De Sitter Thermodynamics from Diamonds's Temperature

The thermal time hypothesis proposed by Rovelli [1] regards the physical basis for the flow of time as thermodynamical and provides a definition of the temperature for some special cases. We verify this hypothesis in the case of de Sitter spacetime by relating the uniformly accelerated observer in de Sitter spacetime to the diamond in Minkowski spacetime. Then, as an application of it, we investigate the thermal effect for the uniformly accelerated observer with a finite lifetime in dS spacetime, which generalizes the corresponding result for the case of Minkowski spacetime [2]. Furthermore, noticing that a uniformly accelerated dS observer with a finite lifetime corresponds to a Rindler observer with a finite lifetime in the embedding Minkowski spacetime, we show that the global-embedding-Minkowski-spacetime (GEMS) picture of spacetime thermodynamics is valid in this case. This is a rather nontrivial and unexpected generalization of the GEMS picture, as well as a further verification of both the thermal time hypothesis and the GEMS picture.Comment: 10 pages, 3 figures, LaTeX; v2: reorganized with a new section added concerning a generalization of the GEMS picture from our result; v3: version with minor corrections, to appear in JHE

Human Parechovirus Infections in Monkeys with Diarrhea, China

Information about human parechovirus (HPeV) infection in animals is scant. Using 5′ untranslated region reverse transcription–PCR, we detected HPeV in feces of monkeys with diarrhea and sequenced the complete genome of 1 isolate (SH6). Monkeys may serve as reservoirs for zoonotic HPeV transmissions and as models for studies of HPeV pathogenesis