Gas exchange measurements in the unsteady state

Leaf level gas exchange is a widely used technique that provides real-time measurement of leaf physiological properties, including CO2 assimilation (A), stomatal conductance to water vapour (gsw) and intercellular CO2 (Ci). Modern open-path gas exchange systems offer greater portability than the laboratory-built systems of the past and take advantage of high-precision infrared gas analyzers and optimized system design. However, the basic measurement paradigm has long required steadystate conditions for accurate measurement. For CO2 response curves, this requirement has meant that each point on the curve needs 1–3 min and a full response curve generally requires 20–35 min to obtain a sufficient number of points to estimate parameters such as the maximum velocity of carboxylation (Vc,max) and the maximum rate of electron transport (Jmax). For survey measurements, the steady-state requirement has meant that accurate measurement of assimilation has required about 1–2 min. However, steady-state conditions are not a strict prerequisite for accurate gas exchange measurements. Here, we present a new method, termed dynamic assimilation, that is based on first principles and allows for more rapid gas exchange measurements, helping to make the technique more useful for high throughput applications

A Trial of the Effect of Micronutrient Supplementation on Treatment Outcome, T Cell Counts, Morbidity, and Mortality in Adults with Pulmonary Tuberculosis.

Tuberculosis (TB) often coincides with nutritional deficiencies. The effects of micronutrient supplementation on TB treatment outcomes, clinical complications, and mortality are uncertain. We conducted a randomized, double-blind, placebo-controlled trial of micronutrients (vitamins A, B complex, C, and E, as well as selenium) in Dar es Salaam, Tanzania. We enrolled 471 human immunodeficiency virus (HIV)-infected and 416 HIV-negative adults with pulmonary TB at the time of initiating chemotherapy and monitored them for a median of 43 months. Micronutrients decreased the risk ofTB recurrence by 45% overall (95% confidence interval [CI], 7% to 67%; P = .02) and by 63% in HIV-infected patients (95% CI, 8% to 85%; P = .02). There were no significant effects on mortality overall; however, we noted a marginally significant 64% reduction of deaths in HIV-negative subjects (95% CI, -14% to 88%; P = .08). Supplementation increased CD3+ and CD4+ cell counts and decreased the incidence of extrapulmonary TB and genital ulcers in HIV-negative patients. Micronutrients reduced the incidence of peripheral neuropathy by 57% (95% CI, 41% to 69%; P < .001), irrespective of HIV status. There were no significant effects on weight gain, body composition, anemia, or HIV load. Micronutrient supplementation could improve the outcome in patients undergoing TB chemotherapy in Tanzania

Managing Performance [in Child Welfare Supervision]

One of the primary roles of a supervisor is to manage worker performance. Performance management is the continuous process of identifying, measuring, and developing the performance of individuals and teams and aligning performance with the strategic goals of the organization (Aguinis, 2007, p. 2). Supervisors must regularly assess current performance levels and take steps to improve performance in a way that is congruent with agency goals. The ultimate goal is to achieve agency objectives through individual and team performance. To effectively manage performance, supervisors must know what the performance expectations are for workers and clearly communicate these expectations to workers. They must regularly monitor and document performance while taking steps to facilitate and improve performance. In the event of unsatisfactory performance patterns, supervisors must analyze and address performance problems, sometimes using disciplinary measures. Finally, formalized performance management systems may include standardized performance evaluations, which supervisors will be expected to complete. In carrying out these multiple responsibilities, supervisors must be aware of and operate within legal guidelines for performance management. Child welfare supervisors with case management experience will find themselves well prepared to manage worker performance. The responsibilities are not unlike those required to help families ensure the safety and well-being of their children. Case management skills related to assessment, collaborative planning, goal setting, problem solving, progress evaluation, and documentation are valuable assets for evaluating and facilitating worker performance. Child welfare supervisors should capitalize on these strengths as they seek to help workers succeed

Managing Performance [in Child Welfare Supervision]

One of the primary roles of a supervisor is to manage worker performance. Performance management is the continuous process of identifying, measuring, and developing the performance of individuals and teams and aligning performance with the strategic goals of the organization (Aguinis, 2007, p. 2). Supervisors must regularly assess current performance levels and take steps to improve performance in a way that is congruent with agency goals. The ultimate goal is to achieve agency objectives through individual and team performance. To effectively manage performance, supervisors must know what the performance expectations are for workers and clearly communicate these expectations to workers. They must regularly monitor and document performance while taking steps to facilitate and improve performance. In the event of unsatisfactory performance patterns, supervisors must analyze and address performance problems, sometimes using disciplinary measures. Finally, formalized performance management systems may include standardized performance evaluations, which supervisors will be expected to complete. In carrying out these multiple responsibilities, supervisors must be aware of and operate within legal guidelines for performance management. Child welfare supervisors with case management experience will find themselves well prepared to manage worker performance. The responsibilities are not unlike those required to help families ensure the safety and well-being of their children. Case management skills related to assessment, collaborative planning, goal setting, problem solving, progress evaluation, and documentation are valuable assets for evaluating and facilitating worker performance. Child welfare supervisors should capitalize on these strengths as they seek to help workers succeed

Precision Spectroscopy at Heavy Ion Ring Accelerator SIS300

Unique spectroscopic possibilities open up if a laser beam interacts with relativistic lithium-like ions stored in the heavy ion ring accelerator SIS300 at the future Facility for Antiproton and Ion Research FAIR in Darmstadt, Germany. At a relativistic factor gamma = 36 the 2P 1/2 level can be excited from the 2S 1/2 ground state for any element with frequency doubled dye-lasers in collinear geometry. Precise transition energy measurements can be performed if the fluorescence photons, boosted in forward direction into the X-ray region, are energetically analyzed with a single crystal monochromator. The hyperfine structure can be investigated at the 2P 1/2 - 2S 1/2 transition for all elements and at the 2P 3/2 - 2S 1/2 transition for elements with Z < 50. Isotope shifts and nuclear moments can be measured with unprecedented precision, in principle even for only a few stored radioactive species with known nuclear spin. A superior relative line width in the order of 5E-7 may be feasible after laser cooling, and even polarized external beams may be prepared by optical pumping

Downregulation of Cinnamyl-Alcohol Dehydrogenase in Switchgrass by RNA Silencing Results in Enhanced Glucose Release after Cellulase Treatment

Cinnamyl alcohol dehydrogenase (CAD) catalyzes the last step in monolignol biosynthesis and genetic evidence indicates CAD deficiency in grasses both decreases overall lignin, alters lignin structure and increases enzymatic recovery of sugars. To ascertain the effect of CAD downregulation in switchgrass, RNA mediated silencing of CAD was induced through Agrobacterium mediated transformation of cv. ‘‘Alamo’’ with an inverted repeat construct containing a fragment derived from the coding sequence of PviCAD2. The resulting primary transformants accumulated less CAD RNA transcript and protein than control transformants and were demonstrated to be stably transformed with between 1 and 5 copies of the TDNA. CAD activity against coniferaldehyde, and sinapaldehyde in stems of silenced lines was significantly reduced as was overall lignin and cutin. Glucose release from ground samples pretreated with ammonium hydroxide and digested with cellulases was greater than in control transformants. When stained with the lignin and cutin specific stain phloroglucinol- HCl the staining intensity of one line indicated greater incorporation of hydroxycinnamyl aldehydes in the lignin

Insect resistance of a full sib family of tetraploid switchgrass \u3ci\u3ePanicum virgatum\u3c/i\u3e L. with varying lignin levels

Little information is available on insect resistance mechanisms and inheritance in biomass grasses. Although reduction of lignin in biomass grasses in order to increase the efficiency of fermentation may result in increased susceptibility to insect feeding, other resistance mechanisms may be more important. Field grown leaves of two tetraploid parent (Kanlow N1, Summer) and 14 progeny switchgrass (Panicum virgatum L.) plant clones selected for a diversity of plant form and ranges in lignin levels were tested for leaf resistance to feeding by the fall armyworm (Spodoptera frugiperda J. E. Smith), a grass feeding insect pest. Although lignin generally appeared important as a resistance mechanism only at early season stages, replicate clones of two low lignin progeny plants generally remained resistant to fall armyworm feeding. Mechanical damaging increased resistance to fall armyworm feeding in several of these plants. Degrees of resistance were sometimes associated with leaf form of progeny. These results indicate there are likely multiple insect resistance mechanisms operating at different stages in switchgrass, and that segregation of some mechanisms appears related to growth form of the plants

Ethanol yields and cell wall properties in divergently bred switchgrass genotypes

Genetic modification of herbaceous plant cell walls to increase biofuels yields is a primary bioenergy research goal. Using two switchgrass populations developed by divergent breeding for ruminant digestibility, the contributions of several wall-related factors to ethanol yields was evaluated. Field grown low lignin plants significantly out yielded high lignin plants for conversion to ethanol by 39.1% and extraction of xylans by 12%. However, across all plants analyzed, greater than 50% of the variation in ethanol yields was attributable to changes in tissue and cell wall architecture, and responses of stem biomass to diluteacid pretreatment. Although lignin levels were lower in the most efficiently converted genotypes, no apparent correlation were seen in the lignin monomer G/S ratios. Plants with higher ethanol yields were associated with an apparent decrease in the lignification of the cortical sclerenchyma, and a marked decrease in the granularity of the cell walls following dilute-acid pretreatment

A new simple method for labeling field crops with stable isotope tracers

Numerous systems have been used to label plants with 13C, which differ in design and complexity depending upon the desired experimental goals. However, most of these systems have generally been applied to greenhouse grown plants. Here, we report on a relatively simple 13C labeling system designed to label crops such as switchgrass (Panicum virgatum L.) grown in the greenhouse or small field plots. The main goals of this study were to validate the system and establish performance benchmarks. We constructed and field tested a simple design plexiglass chamber that was sealed at the soil level with a buried rubber apron. Chamber air was circulated through an infrared gas analyzer to monitor CO2 levels within the chamber. Provisions were made to control temperatures and minimize condensation inside the chamber during labeling. Control experiments using the empty chamber both under greenhouse and field settings showed that decline in CO2 levels was only due to plant CO2 absorption and not due to leakage. Results indicated that the system had generally suitable performance characteristics in both greenhouse and field settings. Isotope enrichment data from our studies revealed that switchgrass fixed 13CO2 that was injected into the chamber within 15-20 min labeling periods. The mean and standard deviation of leaf ᵹ13C values across nine plants enclosed in the chamber was 34 ± 8.9 and 96.1 ± 23.6 for the single and double labeling experiments, respectively. Results indicate that a chamber of this construction type can be effectively used also for labeling other crop plants

Ethanol yields and cell wall properties in divergently bred switchgrass genotypes

Genetic modification of herbaceous plant cell walls to increase biofuels yields is a primary bioenergy research goal. Using two switchgrass populations developed by divergent breeding for ruminant digestibility, the contributions of several wall-related factors to ethanol yields was evaluated. Field grown low lignin plants significantly out yielded high lignin plants for conversion to ethanol by 39.1% and extraction of xylans by 12%. However, across all plants analyzed, greater than 50% of the variation in ethanol yields was attributable to changes in tissue and cell wall architecture, and responses of stem biomass to diluteacid pretreatment. Although lignin levels were lower in the most efficiently converted genotypes, no apparent correlation were seen in the lignin monomer G/S ratios. Plants with higher ethanol yields were associated with an apparent decrease in the lignification of the cortical sclerenchyma, and a marked decrease in the granularity of the cell walls following dilute-acid pretreatment