On-farm adaptation of knowledge-intensive nitrogen management technologies for rice systems

Efficient use of all inputs is vital to achieve and sustain high crop yields, maintain resource quality, and minimize environmental pollution. Fertilizer N is one of the major inputs in rice production. Blanket fertilizer recommendations do not take into account the high field-to-field variability and within-season dynamic changes in indigenous N supply. Since the plant growth reflects the total N supply from all sources, plant N status will be a good indicator of N availability to crops at any given time. The chlorophyll meter (SPAD) and leaf color chart (LCC) are simple, portable diagnostic tools that can measure the crop N status in situ in rice fields to determine the timing of N topdressing. Such decision aids are useful to vary N application rates to rice crops, based on crop demand and indigenous N supply. Although the chlorophyll meter cannot be owned by individual farmers due to its high cost, it is a practically useful tool for field researchers, extension specialists, and crop consultants who do not have access to well-equipped laboratories. On-farm, adaptive research is in progress in 3 countries to adapt the chlorophyll meter technique for transplanted and wet-seeded rice, local cultivar groups, and soil, crop, and environmental conditions. Initial results indicate that the SPAD threshold value of 35 is good for transplanted rice in dry season. The threshold has to be reduced to 32 for wet-seeded rice in dry season and for all rice during wet season with cloudy weather and low radiation. Thus, when calibrated with local cultivar groups and crop conditions, it can be used to accurately monitor crop N status and to advise farmers on N topdressing for rice. It can also be used effectively to verify the adequacy of existing N fertilizer recommendations to rice by the in situ monitoring of foliar N status of crops fertilized with current recommendations and to refine them to further improve N fertilization of rice. The LCC is not as accurate as the chlorophyll meter in determining the leaf N status in rice crops. However, LCC can be calibrated with the chlorophyll meter to fix the critical color shade for local rice cultivar groups and crop conditions. Farmers can, then, use the LCC to qualitatively assess foliar N status and adjust N topdressing to their rice crops. Initial feedback on the use of LCC from farmer cooperators in the Philippines is highly encouraging. Both methods are affected by factors such as varietal group, plant density, crop stress that causes leaf chlorosis, soil nutrient status, and climate; therefore, they have to be adapted to specific soil, climatic, and crop conditions. Adequate training is necessary for both extension agents and farmers to properly use the new tools for increasing the efficiency N fertilizer use on rice. Wider farmer adoption of the two diagnostic tools discussed in this paper will minimize over-fertilization of rice, increase profitability, and decrease fertilizer-related pollution of the environment.     

Cloud Data Encryption and Authentication Based on Enhanced Merkle Hash Tree Method

Many organizations apply cloud computing to store and effectively process data for various applications. The user uploads the data in the cloud has less security due to the unreliable verification process of data integrity. In this research, an enhanced Merkle hash tree method of effective authentication model is proposed in the multi-owner cloud to increase the security of the cloud data. Merkle Hash tree applies the leaf nodes with a hash tag and the non-leaf node contains the table of hash information of child to encrypt the large data. Merkle Hash tree provides the efficient mapping of data and easily identifies the changes made in the data due to proper structure. The developed model supports privacy-preserving public auditing to provide a secure cloud storage system. The data owners upload the data in the cloud and edit the data using the private key. An enhanced Merkle hash tree method stores the data in the cloud server and splits it into batches. The data files requested by the data owner are audit by a third-party auditor and the multi-owner authentication method is applied during the modification process to authenticate the user. The result shows that the proposed method reduces the encryption and decryption time for cloud data storage by 2–167 ms when compared to the existing Advanced Encryption Standard and Blowfish.     

n-MOSFET With Silicon–Carbon Source/Drain for Enhancement of Carrier Transport

A novel strained-silicon (Si) n-MOSFET with 50-nm gate length is reported. The strained n-MOSFET features silicon-carbon (Si_1-yC_y) source and drain (S/D) regions formed by a Si recess etch and a selective epitaxy of Si_1-yC_y in the S/D regions. The carbon mole fraction incorporated is 0.013. Lattice mismatch of ~0.56% between Si _0.987C_0.013 and Si results in lateral tensile strain and vertical compressive strain in the Si channel region, both contributing to substantial electron-mobility enhancement. The conduction-band offset DeltaE_c between the Si_0.987 C_0.013 source and the strained Si channel could also contribute to an increased electron injection velocity nu_inj from the source. Implementation of the Si_0.987 C_0.013 S/D regions for n-MOSFET provides significant drive current I_Dsat enhancement of up to 50% at a gate length of 50 nm     

Aqueous high-temperature chemistry of carbo- and heterocycles: Part 24. First demonstration of specific C-C bond scission of the pyridine ring. Reactions of piperidine,pyridine and some of their methyl derivatives in aqueous formic acid

In its reactions with the title compounds, formic acid variously acts as a formylating, methylating, and reducing agent. Both pyridine and piperidine are converted in significant amounts into 1-methyl-, 1-ethyl-, 1-propyl- and 1-pentyl-piperidines. Of the N-alkyl groups, isotopic labeling shows that only N-methyl derives from the formic acid, while the N-ethyl and N-propyl arise from heterocyclic ring C-C bond scission by retro-vinylogous-bis-aza-Aldol reactions. Detailed analysis of the products for pyridine, piperidine, and their 4-methyl derivatives, reacted separately and mixed, supports mechanisms in which a piperidine adds 1,2 to a pyridinium cation, or to a di- or tetra-hydropyridine, to initiate reaction sequences leading to the product slates found.