Highly Selective Preparation of 3-and 6-Modified Mannose/Altrose Derivatives

A highly efficient method to get 3-and 6-modified mannose/ahrose derivatives for oligosaccharide synthesis is described. All the compounds were obtained exclusively with the combinations of 3-and/or 6-hydroxyl protection and/or activation（ including the configuration conversion of 3-carbon atom）.

Selected abstracts of the symposium onenvironmental protection and ecologyin developing countries

Nov. 1—4, 1989, Beijing, China River water chemistry in India-An overview V. Subramamian School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India. Based on extensive analyses of a very large number of samples, the average river water in India is more alkaline than the world average river water. The dominance of Na and Cl in Indian river shows their monsoon control. There are spatial and seasonal variations. The northern river are less saline than the southern rivers. The sediments covered by the Ganges-

Application of fractal theory in detecting low current faults of power distribution system in coal mines

Single-phase low current grounding faults areoften seen in power distribution system of coal mines.These faults are difficult to reliably identify.We propose a new method of single-phase ground fault protection based upon a discernible matrix of the fractal dimension associated with line currents.The method builds on existing selective protection methods.Faulted feeders are distinguished using differences in the zero-sequence transient current fractal dimension.The current signals were first processed through a fast Fourier transform and then the characteristics of a faulted line were identified using a discernible matrix.The method of calculation is illustrated.The results show that the method involves simple calculations, is easy to do and is highly accurate.It is, therefore, suitable for distribution networks having different neutral grounding modes.

Site Fidelity and Residency of Tursiops truncatus off the Aragua Coast,Venezuela-First Records of Long Residency

This study represents the first comprehensive analysis of the residency patterns of a coastal population of bottlenose dolphin off the coast of Aragua,Venezuela,over a multi-year period.Using photo-identification,the most recent study(2019-2020)identified 56 individuals with the time between encounters from one to 344 days between the first and last sighting.Site Fidelity(SF)and Residence(RES)indices were calculated and Agglomerative Hierarchical Clustering(AHC)modeling was performed,with three patterns of residence obtained:resident(25%),semi-resident(17.86%)and transient(57.14%).These results were contrasted with remodeled data from a previous study(2006-2007),showing similar patterns:resident(24.44%),semi-resident(28.89%)and transient(46.67%).Importantly,two individuals were found to have been resident over the extended period.A breeding female sighted for the first time in 2004 and again in 2020(16 years)and the other from 2005 to 2020(15 years).This region is an important area for marine mammals,known to support a resident reproductive population over many years,as well seabirds,sea turtles,whale sharks and fishermen.We recommend that consideration be given to designating the waters as a Marine Protected Area to safeguard the existing population and provide benefit to the surrounding marine environment.

Partial-TMR: A New Method for Protecting Register Files Against Soft Error Based on Lifetime Analysis

High-energy particles in the space can easily cause soft error in register file(RF).As a critical structure in a processor,RF often stores data for long periods of time and is read frequently,resulting in a higher probability of spreading corrupted data to other parts of the processor.The triple modular redundancy(TMR)is a common and effective fault tolerance method that enables multi-bit error correction.Designing full TMR for all the registers could cause excessive area and power overheads.However,some registers in RF have less impact on processor reliability.Therefore,there is no need to design TMR for them.This paper designs an efficient strategy which can rate the registers in RF based on their vulnerability.Based on the proposed strategy,a new RF fault tolerance method named Partial-TMR formulates in this paper,which selectively protects more vulnerable registers against multi-bit error,and improves fault tolerance efficiency.For integer RF,Partial-TMR improves its soft error correction capability by 24.5%relative to the baseline system and 3%relative to ParShield,while for floating-point RF,the improvement comes to 5.17%and 0.58%respectively.The soft error correction capability of Partial-TMR is slightly lower than that of full TMR by 1%to 3%,but Partial-TMR significantly cuts the area and power overheads.Compared with full TMR,Partial-TMR decreases the area and power overheads by 71.6%and 64.9%,respectively.It also has little impact on the performance.Partial-TMR is a more cost-effective fault tolerance method compared with ParShield and full TMR.