Assessing soybean leaf area and leaf biomass by spectral measurements

Red and photographic infrared spectral radiances were correlated with soybean total leaf area index, green leaf area index, chlorotic leaf area index, green leaf biomass, chlorotic leaf biomass, and total biomass. The most significant correlations were found to exist between the IR/red radiance ratio data and green leaf area index and/or green leaf biomass (r squared equals 0.85 and 0.86, respectively). These findings demonstrate that remote sensing data can supply information basic to soybean canopy growth, development, and status by nondestructive determination of the green leaf area or green leaf biomass

Comparisons between systems to measure contact and flight times in elite race walking

Race walking is an Olympic event dictated by a rule that states that no visible loss of contact with the ground should occur and that the leg must be straightened from first contact with the ground until the ‘vertical upright position’ (IAAF Rule 230.2). The measurement of flight times during race walking is therefore of great interest to coaches, athletes and judges. The aim of the study was to compare different methodologies used to measure contact and flight time in race walking. Ten male race walkers (stature: 1.78 m (± 0.05), mass: 64.4 kg (± 4.9)) and seven female race walkers (stature: 1.68 m (± 0.10), mass: 56.7 kg (± 11.0)) participated. Fourteen of the athletes had competed at the 2016 Olympic Games or 2017 World Championships. The men race walked down an indoor track at 11, 12, 13, 14 and 15 km/h (measured using timing gates and in a randomised order), whereas the women’s trials were at 10, 11, 12, 13 and 14 km/h. Contact and flight times were measured for the midsection of each trial using three adjacent 900 x 600 mm Kistler force plates (1000 Hz), 5 x 1 m strips of an OptoJump Next system (1000 Hz) and a Fastec high-speed camera (500 Hz). Results from the OptoJump Next system were extracted using five settings based on the number of LEDs that needed activating (contact begins after_contact ends when), and were annotated as 0_0, 1_1, 2_2, 3_3 and 4_4. The force plate values were considered the criterion values and measurements were assessed for reliability using Intraclass Correlation Coefficients (ICC) and 95% limits of agreement (LOA: bias ± random error). For flight time, the ICCs between the force plate and OptoJump Next were 0.846 for the 0_0 condition (LOA: .011 ± .014 s), 0.901 (1_1) (LOA: .008 ± .014 s), 0.983 (2_2) (LOA: .000 ± .008 s), 0.844 (3_3) (LOA: –.011 ± .014 s), and 0.563 (4_4) (LOA: –.023 ± .018 s). The ICC between the force plate and the high-speed video for flight time was 0.975 (LOA: –.003 ± .008 s). For contact time, the ICCs between the force plate and OptoJump Next were 0.967 for the 0_0 condition (LOA: –.011 ± .011 s), 0.982 (1_1) (LOA: –.008 ± .010 s), 0.995 (2_2) (LOA: .000 ± .010 s), 0.960 (3_3) (LOA: .011 ± .016 s), and 0.874 (4_4) (LOA: .024 ± .015 s). The ICC between the force plate and the high-speed video condition for contact time was 0.991 (LOA: .004 ± .010 s). The OptoJump Next system provided results similar to those of the gold standard force plates, with the 2_2 setting the most reliable. Users of the OptoJump Next system should therefore note that adjusting the settings of the device (from 0_0, the most likely default setting) might be necessary to achieve the most accurate results. The high-speed video recordings also provided very good reliability although the time-consuming nature of video analysis means the OptoJump Next system is better suited to providing immediate results

A computer operated mass spectrometer system

Digital computer system for processing mass spectrometer output dat

Computer control of mass analyzers

Digital computer control of mass spectrometer

Cardiovascular Risk Factors and Dehydroepiandrosterone Sulfate Among Latinos in the Boston Puerto Rican Health Study.

Low blood dehydroepiandrosterone sulfate (DHEAS) levels have strong positive associations with stroke and coronary heart disease. However, it is unclear whether DHEAS is independently associated with cardiovascular risk factors. Therefore, we examined the association between cardiovascular risk factors and DHEAS concentration among a high-risk population of Latinos (Puerto Ricans aged 45 to 75 years at baseline) in a cross-sectional analysis of the Boston Puerto Rican Health Study. Of eligible participants, 72% completed baseline interviews and provided blood samples. Complete data were available for 1355 participants. Associations between cardiovascular risk factors (age, sex, total cholesterol, high-density lipid cholesterol, triglycerides, and glucose) and log-transformed DHEAS (μg/dL) were assessed. In robust multivariable regression analyses, DHEAS was significantly inversely associated with age (β = -12.4; 95% CI: -15.2, -9.7; per 5 years), being female (vs. male) (β = -46; 95% CI: -55.3, -36.6), and plasma triglyceride concentration (β = -0.2; 95% CI: -0.3, -0.1; per 10 mg/dL) and was positively associated with total cholesterol and plasma glucose levels (β = 1.8; 95% CI: 0.6, 3 and β = 0.2; 95% CI: 0.04, 0.3, respectively, per 10 mg/dL) after adjustment for smoking, alcohol, and physical activity and for postmenopausal hormone use in women. Estimates were unchanged after adjustment for measures of chronic disease and inflammation. Women exhibited a stronger age-related decline in DHEAS and a positive association with glucose in contrast to findings among men (P interaction < 0.05). In conclusion, in this large study of Latinos with a heavy cardiovascular risk factor burden, we observed significant associations between cardiovascular disease (CVD) risk factors and DHEAS, with variations by sex. These findings improve our understanding of the role DHEAS may play in CVD etiology

Lack of Z-DNA Conformation in Mitomycin-Modified Polynucleotides Having Inverted Circular Dichroism

Poly(dG-dC)· poly(dG-dC) and Micrococcus lysodeikticus DNA were modified by exposure to reductively activated mitomycin C, an antitumor antibiotic. The resulting covalent drug-polynucleotide complexes displayed varying degrees of CD inversions, which are strikingly similar to the inverted spectrum observed with Z-DNA. The following criteria have been used to establish, however, that the inverted CD pattern seen in mitomycin C-polynucleotide complexes does not reflect a Z-DNA conformation. (i) The ethanol-induced transition of poly(dG-dC)· poly(dG-dC) from B to Z conformation is not facilitated but rather is inhibited by mitomycin C modification. This may be due to the presence of crosslinks. (ii) Radioimmunoassay indicated no competition for Z-DNA-specific antibody by any of the mitomycin C-modified polynucleotides. (iii) 31P NMR of the complexes yielded a single relatively narrow resonance, which is inconsistent with the dinucleotide repeat characteristic of Z-DNA. Alternative explanations for the inverted CD pattern include a drug-induced left-handed but non-Z conformational change or the superposition of an induced CD onto the CD of B-DNA due to drug-base electronic interactions. These results illustrate the need for caution in interpreting CD changes alone as an indication of Z-DNA conformation

The Relationship of Red and Photographic Infrared Spectral Data to Grain Yield Variation Within a Winter Wheat Field

Two band hand-held radiometer data from a winter wheat field, collected on 21 dates during the spring growing season, were correlated within field final grain yield. Significant linear relationships were found between various combinations of the red and photographic infrared radiance data collected and the grain yield. The spectral data explained approximately 64 percent of the within field grain yield variation. This variation in grain yield could not be explained using meteorological data as these were similar for all areas of the wheat field. Most importantly, data collected early in the spring were highly correlated with grain yield, a five week time window existed from stem elongation through antheses in which the spectral data were most highly correlated with grain yield, and manifestations of wheat canopy water stress were readily apparent in the spectral data

Remote sensing of total dry-matter accumulation in winter wheat

The author has identified the following significant results. Red and photographic-infrared spectral data collected on 21 dates over the growing season with a hand-held radiometer was quantitatively correlated with total dry-matter accumulation in winter wheat. The spectral data were found to be highly related to vigor and condition of the plant canopy. Two periods of drought stress and subsequent recovery from it were readily apparent in the spectral data. Simple ratios of the spectral data compensated for variations in solar intensities and, when integrated over the growing season, explained 79% of the variation in total above-ground accumulation of dry matter

An Analysis of Lower Body Kinematics in Response to Changes in Speed in World-Class Walkers

Information on how race walkers modulate lower body kinematics with speed is of interest to coaches for developing informed training strategies for elite athletes. Seven male Olympic race walkers volunteered to participate in the study. Twelve optoelectronic cameras (Oqus 7, Qualisys) operating at 250 Hz collected kinematic data as participants race walked at 3 different speeds down the 40 m walkway. Statistical parametric mapping (spm1d.org) was used to compare lower body kinematics in Matlab (R2016b, The Mathworks Inc.). Greater hip flexion (4°) was observed at 80-92% of the gait cycle in the 10 km trials than the training pace trials (p < 0.001, medium effect (0.65)). A more flexed hip during terminal swing in the 10 km trials might be indicative of the 0.08 m increase in step length that was present with increases in race walking speed. At the knee, greater flexion (3°) occurred during the 10 km trials than the training pace trials at 68-73% (p < 0.001, medium effect (0.5)). This study suggests that elite race walkers modulate lower body kinematics by increasing range of motion of the hip and knee as speed increases. Coaches and athletes should consider an individualised approach to this kinematic strategy with respect to the rules of race walking