Field spectrometer to measure percent ground coverage and leaf area index of agriculture crops

Measurement of percent ground cover (PGC) and leaf area index (LAI) are required for crop modelling, yield estimation and for ground truth data in remote sensing studies. An instrument which traverses on a track above a crop and continuously measures the ratio of incident and reflected radiation at various wavelengths was developed and tested. Spectral irradiance and reflectance measurements were made at four wavelengths (647.8, 675.5, 739.9, 790.4 nm) at eight stages of growth of wheat and barley for three crop densities. Data provided information on the relations between spectral properties at selected wavelength and leaf area expansion at different growth stages. The spectral data were highly correlated with leaf area index measurements

Variations of crop canopy spectral reflectance measurements under changing sky conditions

The possibility of using reflectance data collected under both cloudy and sunny conditions is studied. Extrenle values of red and far-red reflectances measured directly over bare soil and crop canopies during intermittently cloudy conditions can differ by more than 100 percent and 60 percent, respectively. Eliminating the irradiance variations by using only data collected under sunny conditions reduced such variation to within 1 percent for bare soil and to within 8 percent and 20 percent for crop canopy red and far-red reflectances, respectively. In general, the reflectances measured under cloudy conditions with relatively constant irradiance values are constant and approximately 10 percent larger than the ones measured at similar sun angles during sunny conditions. This result is independent of the species and the spectral regions under study

Field spectrometer to measure percent ground coverage and leaf area index of agriculture crops [remote sensing]

Measurement of percent ground cover (PGC) and leaf area index (LAI) are required for crop modelling, yield estimati-on and for ground truth data in remote sensing studies. An instrument which traverses on a track above a crop and continuously measures the ratio of incident and reflected radiation at various wavelengths was developed and tested. Spectral irradiance and reflectance measurements were made at four wavelengths (647.8 , 675.5 , 739.9 , 790.4 nm) at eight stages of growth of wheat and barley for three crop densities. Data provided information on the relations between spectral properties at selected wavelength and leaf area expansion at different growth stages. The spectral data were highly correlated with leaf area index measurements

Variabilité introduite dans des mesures de réflectances spectrales de couverts végétaux agricoles par les facteurs état du ciel et vent

Parmi les facteurs introduisant de la variabilité indésirable dans les mesures de réflectance spectrale prises au-dessus de couverts végétaux, ceux de type radiatif ont été moins étudiés. A l'aide d'expériences isolant certains de ces facteurs et de méthodes empiriques d'analyses, nos résultats montrent que la présence de radiation diffuse non-directionnelle dans la radiation solaire incidente n'introduit pas beaucoup de variabilité indésirable dans les mesures de réflectance spectrale. Ils montrent aussi que la présence de nuages vis-à-vis le disque solaire entraîne généralement une sous-estimation des réflectances mesurées sous ces conditions par rapport aux conditions de ciel serein. Il semble toutefois possible de corriger cette erreur et ainsi d'utiliser indifféremment l'une ou l'autre de ces deux conditions radiatives pour relier les mesures de réflectances spectrales prises au niveau du sol à des paramètres du couvert végétal. Le vent est un autre facteur qui introduit passablement de variabilité indésirable dans ces mesures. Si la structure du couvert, la région spectrale et la vitesse du vent font varier l'importance de ce facteur, il n'en demeure pas moins que ces fluctuations continuelles dans le temps peuvent conduire à mesurer des réflectances qui ne sont pas représentatives de la réflectance réelle du couvert végétal au moment de la mesure. Many factors including the radiative ones introduce indesirable variability in measurements of spectral reflectance. Based upon experimental studies related to one specific factor at a time and a1so on empirica1 method of analysis, our results show that non-directional diffuse radiation from incident solar radiation introduce little indesirable variability in spectral reflectance measurements. They also show that clouds hiding the solar disc 1ead usually to an underestimation of reflectances measured under these conditions compared to those measured under clear sky. However, it seems easy to account for this difference. It then implies that the measurement of the spectral reflectances at the ground level under either one of these radiative conditions will give values which will be possible to relate to plant canopy structure

Towards comprehensive and transparent reporting: context-specific additions to the ICF taxonomy for medical evaluations of work capacity involving claimants with chronic widespread pain and low back pain

BACKGROUND: Medical evaluations of work capacity provide key information for decisions on a claimant's eligibility for disability benefits. In recent years, the evaluations have been increasingly criticized for low transparency and poor standardization. The International Classification of Functioning, Disability and Health (ICF) provides a comprehensive spectrum of categories for reporting functioning and its determinants in terms of impairments and contextual factors and could facilitate transparent and standardized documentation of medical evaluations of work capacity. However, the comprehensiveness of the ICF taxonomy in this particular context has not been empirically examined. In this study, we wanted to identify potential context-specific additions to the ICF for its application in medical evaluations of work capacity involving chronic widespread pain (CWP) and low back pain (LBP).METHODS: A retrospective content analysis of Swiss medical reports was conducted by using the ICF for data coding. Concepts not appropriately classifiable with ICF categories were labeled as specification categories (i.e. context-specific additions) and were assigned to predefined specification areas (i.e. precision, coverage, personal factors, and broad concepts). Relevant specification categories for medical evaluations of work capacity involving CWP and LBP were determined by calculating their relative frequency across reports and setting a relevance threshold.RESULTS: Forty-three specification categories for CWP and fifty-two for LBP reports passed the threshold. In both groups of reports, precision was the most frequent specification area, followed by personal factors.CONCLUSIONS: The ICF taxonomy represents a universally applicable standard for reporting health and functioning information. However, when applying the ICF for comprehensive and transparent reporting in medical evaluations of work capacity involving CWP and LBP context-specific additions are needed. This is particularly true for the documentation of specific pain-related issues, work activities and personal factors. To ensure the practicability of the multidisciplinary evaluation process, the large number of ICF categories and context-specific additions necessary for comprehensive documentation could be specifically allocated to the disciplines in charge of their assessment.<br/

Self-diffusion in granular gases

The coefficient of self-diffusion for a homogeneously cooling granular gas changes significantly if the impact-velocity dependence of the restitution coefficient $\epsilon$ is taken into account. For the case of a constant $\epsilon$ the particles spread logarithmically slow with time, whereas the velocity dependent coefficient yields a power law time-dependence. The impact of the difference in these time dependences on the properties of a freely cooling granular gas is discussed.Comment: 6 pages, no figure

Mapping of Dietary Interventions Beneficial in the Prevention of Secondary Health Conditions in Spinal Cord Injured Population: A Systematic Review.

OBJECTIVES Individuals with spinal cord injury are at risk of secondary health conditions (SHC) that develop as a consequence of autonomic dysfunction, prolonged oxidative stress and inflammation, and physical inactivity coupled with inadequate energy and nutritional intake. SHC can be debilitating and even life-threatening, and its prevention remains one of the major challenges in the continuum of medical care of aging SCI population. An unhealthy diet is a major driver of inflammation, oxidative stress, and unfavourable metabolic status and may be a practical preventive target to tackle increased SHC risk post-injury. AIMS To provide a catalogue of dietary interventions beneficial in prevention of SHC among individuals with SCI by conducting a systematic review of the literature on dietary interventions and dietary supplementation in promoting health and well-being after the injury. In addition, we aimed to provide a summary of observational studies exploring the association between habitual diet (macro- and micronutrients intake and dietary patterns) and health patterns following the injury. METHOD This review was registered at PROSPERO (University of York) with registration number CRD42022373773. Four medical databases (EMBASE.com, MEDLINE [Ovid], Cochrane CENTRAL, and Web of Science Core Collection) and Google Scholar were searched from inception until 11th July 2022. Studies were included if they were clinical trials or observational studies conducted in adult individuals with SCI and provided information of interest. Based on strength of the study design and risk of bias assessment (using the NIH tool), we classified studies from Level 1 (most reliable studies) to Level 4 (least reliable studies). RESULTS Of 12,313 unique citations, 47 articles (based on 43 original studies) comprising 32 interventional (22 RCTs, 3 NRCT, and 7 pre-post studies) and 11 observational studies (2 cohort studies, 2 case-control, 1 post-intervention follow-up study, and 6 cross-sectional studies) were included in the present systematic review. Twenty studies (46.5%) were classified as Level 1 or 2, indicating high/moderate methodological quality. Based on those studies, dietary strategies including high protein diet, intermittent fasting, balanced diet in combination with physical conditioning and electrical stimulation, and dietary supplementation including alpha-lipoic acid, creatine, vitamin D, and cranberry-derived supplements and probiotics were mapped as the most promising in prevention of SHC among individuals with SCI. CONCLUSIONS To develop timely and effective preventive strategies targeting major SHC (e.g., cardiometabolic diseases, urinary tract infections) in SCI, further research is warranted to confirm the effectiveness of dietary strategies/interventions identified through the current systematic review of the literature