Rounding Numbers: Why The \u27\u27new System\u27\u27 Doesn\u27t Work

This paper explains a correction to the rounding rule previously publishedin this Journal. The earlier article reported that the best way to roundnumbers is to always round up when the first digit dropped is 5. However,this will lead to accumulation of error when errors are averaged. Arounding strategy that leads to less error is to round up when 5 isfollowed by any nonzero digits, but to round even when 5 is followed byzeros or no other digits. By rounding the last kept digit to an evennumber, half the time the digit is increased and half the time it is keptthe same so that errors tend to cancel when averaged

Photocycloaddition Of 4,5\u27,8-trimethylpsoralen And Oleic-acid Methyl-ester - Product Structures And Reaction-mechanism

The stereochemical structures of the four adducts formed between oleic acid methyl ester (OAME) and 4,5\u27,8-trimethylpsoralen (tmPso) have been determined. Assignment of the tmPso \u27H NMR spectrum was accomplished by analogy to two coumarin model compounds and with the use of homonuclear decoupling and resonance enhancement. Assignment of the lH NMR spectra for the OAME-tmPso adducts was made by analogy to the spectra of OAME and tmPso and using 2D &resolved and COSY analyses. The configurations of the cyclobutyl rings in these adducts was determined by The stereochemical structures of the four adducts formed between oleic acid methyl ester (OAME) and 4,5\u27,8-trimethylpsoralen (tmPso) have been determined. Assignment of the tmPso \u27H NMR spectrum was accomplished by analogy to two coumarin model compounds and with the use of homonuclear decoupling and resonance enhancement. Assignment of the lH NMR spectra for the OAME-tmPso adducts was made by analogy to the spectra of OAME and tmPso and using 2D &resolved; and COSY analyses. The configurations of the cyclobutyl rings in these adducts was determined by MM2 energy minimization calculations, homonuclear \u27H NOE analysis, and comparison of products obtained with cis-OAME and trans-EAME (elaidic acid methyl ester). Only four of the eight possible disastereomeric adducts are detected. These adducts have the cis-cis- , cis-cis-HT, trans-cis- , and trans-cis-HT configurations. The lack of formation of the other isomers may be due to the geometric requirements of exciplex formation. The mechanism of the reaction was established to involve initial bond formation at the 4 position of tmPso, most likely to form a diradical intermediate. The rate of dissociation of the trans diradical is much faster than ring closure, in contrast to the cis diradical whose rate of ring closure is at least as fast as dissociation. The rate of cis-trans isomerization of the 9,lO-bond of the fatty ester portion of the diradical is faster than ring closure for the cis diradical and slower than ring closure for the trans diradical

Sequence-specific Photomodification Of Dna By An Oligonucleotide-phenanthrodihydrodioxin Conjugate

We introduce a new member of a family of photochemically active oligonucleotide conjugates. A Phenanthrodihydrodioxin (PDHD)-based agent was synthesized and covalently linked to a 5\u27-end of the 9-mer oligonucleotide via a hexamethylene linker. The conjugate hybridized to a complementary 30-nucleotide-long target and efficiently cleaved it in a sequence specific manner. Up to 67% of target was specifically damaged (51% cross-links and 16% direct cleavage). While the photosensitizer alone nonspecifically damaged only Gs in a single-stranded target, its conjugate cross-linked to and damaged also A, T, and C sites in a target in agreement with duplex and tripler formation

Establishing a Flexible but Robust Framework to Assess Nutrient Removal in Diverse Wetland Restorations

Globally, investments are made to protect, restore, construct, and manage wetland ecosystems to mitigate eutrophication. However, efforts to assess nutrient removal in restored wetlands are often limited and data remains inadequate. In Ohio, wetland restoration is being implemented statewide as part of the H2Ohio Initiative to improve water quality. The H2Ohio Wetland Projects are diverse and numerous, representing over 50 projects including reconnection of diked coastal wetlands as well as wetland restoration and construction on agricultural land and floodplains. The H2Ohio Wetland Monitoring Program (HWMP) includes a multi-disciplinary, coordinated team of researchers developing a long-term data collection framework to assess the nutrient removal effectiveness of wetland restoration throughout the state. We are developing a tiered approach to maximize use of limited resources by intensively investigating and modeling selected representative projects and developing synthetic analyses to infer biogeochemical process from low resolution indicators in less intensively monitored projects. Monitoring will take a mass balance nutrient budgeting approach aimed at quantifying major pools and fluxes of nitrogen and phosphorus to quantify load reduction in contrasting restoration approaches. Measurements will include hydrologic dynamics, groundwater exchange, vegetation dynamics, soil and surface nutrient status, surface water nutrient concentrations, and sediment-surface water nutrient exchange. Ultimately, the HWMP provides an unprecedented opportunity to compare diverse wetland restoration, construction, and management approaches in terms of direct assessments of nutrient cycling mechanisms. The HWMP will not only generate open data to inform wetland research and management, but will also enhance capacity through cultivating a network of researchers and practitioners

Establishing a Flexible but Robust Framework to Assess Nutrient Removal in Diverse Wetland Restorations

Globally, investments are made to protect, restore, construct, and manage wetland ecosystems to mitigate eutrophication. However, efforts to assess nutrient removal in restored wetlands are often limited and data remains inadequate. In Ohio, wetland restoration is being implemented statewide as part of the H2Ohio Initiative to improve water quality. The H2Ohio Wetland Projects are diverse and numerous, representing over 50 projects including reconnection of diked coastal wetlands as well as wetland restoration and construction on agricultural land and floodplains. The H2Ohio Wetland Monitoring Program (HWMP) includes a multi-disciplinary, coordinated team of researchers developing a long-term data collection framework to assess the nutrient removal effectiveness of wetland restoration throughout the state. We are developing a tiered approach to maximize use of limited resources by intensively investigating and modeling selected representative projects and developing synthetic analyses to infer biogeochemical process from low resolution indicators in less intensively monitored projects. Monitoring will take a mass balance nutrient budgeting approach aimed at quantifying major pools and fluxes of nitrogen and phosphorus to quantify load reduction in contrasting restoration approaches. Measurements will include hydrologic dynamics, groundwater exchange, vegetation dynamics, soil and surface nutrient status, surface water nutrient concentrations, and sediment-surface water nutrient exchange. Ultimately, the HWMP provides an unprecedented opportunity to compare diverse wetland restoration, construction, and management approaches in terms of direct assessments of nutrient cycling mechanisms. The HWMP will not only generate open data to inform wetland research and management, but will also enhance capacity through cultivating a network of researchers and practitioners