6,041 research outputs found

    An empirical, graphical, and analytical study of the relationship between vegetation indices

    Get PDF
    The development of formulae for the reduction of multispectral scanner measurements to a single value (vegetation index) for predicting and assessing vegetative characteristics is addressed. The origin, motivation, and derivation of some four dozen vegetation indices are summarized. Empirical, graphical, and analytical techniques are used to investigate the relationships among the various indices. It is concluded that many vegetative indices are very similar, some being simple algebraic transforms of others

    Estimation of within-stratum variance for sample allocation: Foreign commodity production forecasting

    Get PDF
    The problem of determining the stratum variances required for an optimum sample allocation for remotely sensed crop surveys is investigated with emphasis on an approach based on the concept of stratum variance as a function of the sampling unit size. A methodology using the existing and easily available information of historical statistics is developed for obtaining initial estimates of stratum variances. The procedure is applied to variance for wheat in the U.S. Great Plains and is evaluated based on the numerical results obtained. It is shown that the proposed technique is viable and performs satisfactorily with the use of a conservative value (smaller than the expected value) for the field size and with the use of crop statistics from the small political division level

    Stratum variance estimation for sample allocation in crop surveys

    Get PDF
    The problem of determining stratum variances needed in achieving an optimum sample allocation for crop surveys by remote sensing is investigated by considering an approach based on the concept of stratum variance as a function of the sampling unit size. A methodology using the existing and easily available information of historical crop statistics is developed for obtaining initial estimates of tratum variances. The procedure is applied to estimate stratum variances for wheat in the U.S. Great Plains and is evaluated based on the numerical results thus obtained. It is shown that the proposed technique is viable and performs satisfactorily, with the use of a conservative value for the field size and the crop statistics from the small political subdivision level, when the estimated stratum variances were compared to those obtained using the LANDSAT data

    Imputing historical statistics, soils information, and other land-use data to crop area

    Get PDF
    In foreign crop condition monitoring, satellite acquired imagery is routinely used. To facilitate interpretation of this imagery, it is advantageous to have estimates of the crop types and their extent for small area units, i.e., grid cells on a map represent, at 60 deg latitude, an area nominally 25 by 25 nautical miles in size. The feasibility of imputing historical crop statistics, soils information, and other ancillary data to crop area for a province in Argentina is studied

    Risk Factors for Diarrhea in Children Under Five Years of Age Residing in Peri-Urban Communities in Cochabamba, Bolivia

    Get PDF
    This study examined the relationship between childhood diarrhea prevalence and caregiver knowledge of the causes and prevention of diarrhea in a prospective cohort of 952 children \u3c 5 years of age in Cochabamba, Bolivia. The survey of caregiver knowledge found that more than 80% of caregivers were unaware that hand washing with soap could prevent childhood diarrhea. Furthermore, when asked how to keep food safe for children to eat only 17% of caregivers reported hand washing before cooking and feeding a child. Lack of caregiver awareness of the importance of practices related to hygiene and sanitation for diarrhea prevention were significant risk factors for diarrheal disease in this cohort. The knowledge findings from this study suggest that health promotion in these communities should put further emphasis on increasing knowledge of how water treatment, hand washing with soap, proper disposal of child feces, and food preparation relate to childhood diarrhea prevention

    144 EFFECT OF ANTRAL FOLLICLE COUNT IN BEEF HEIFERS ON \u3ci\u3eIN VITRO\u3c/i\u3e FERTILIZATION/PRODUCTION

    Get PDF
    Our objective has been to compare the IVF and in vitro production (IVP) of embryos from low and high antral follicle count (AFC) heifers. This is the fourth year of the study with years 1 to 3 reported individually. For this report, we add data for the fourth year and present a combined analysis (years 1 to 4) for the first time. Each year, AFC was determined on ~120 Angus heifers using transrectal ultrasonography. Ten heifers with the lowest AFC and 10 heifers with the highest AFC and all with evidence of oestrous cyclicity were synchronized with two 5-mL injections of PGF2α 11 days apart. Half were harvested on Day 5 to 6 and half on Day 15 to 16 of the oestrous cycle. The IVF procedure was slightly modified each year. For year 4, the IVF procedure included protocols for semi-defined media and was as described (IVP Protocol, P. J. Hansen’s Laboratory, University of Florida). Cumulus-oocyte complexes (COC) from follicles less than 8 mm in diameter were cultured in maturation medium (5% CO2; 38.5°C) for 24 h

    Phonon Properties of Knbo3 and Ktao3 from First-Principles Calculations

    Full text link
    The frequencies of transverse-optical Γ\Gamma phonons in KNbO3_3 and KTaO3_3 are calculated in the frozen-phonon scheme making use of the full-potential linearized muffin-tin orbital method. The calculated frequencies in the cubic phase of KNbO3_3 and in the tetragonal ferroelectric phase are in good agreement with experimental data. For KTaO3_3, the effect of lattice volume was found to be substantial on the frequency of the soft mode, but rather small on the relative displacement patterns of atoms in all three modes of the T1uT_{1u} symmetry. The TO frequencies in KTaO3_3 are found to be of the order of, but somehow higher than, the corresponding frequencies in cubic KNbO3_3.Comment: 8 pages + 1 LaTeX figure, Revtex 3.0, SISSA-CM-94-00

    Technical assessment of Mir-1 life support hardware for the international space station

    Get PDF
    NASA has been progressively learning the design and performance of the Russian life support systems utilized in their Mir space station. In 1992, a plan was implemented to assess the benefits of the Mir-1 life support systems to the Freedom program. Three primary tasks focused on: evaluating the operational Mir-1 support technologies and understanding if specific Russian systems could be directly utilized on the American space station and if Russian technology design information could prove useful in improving the current design of the planned American life support equipment; evaluating the ongoing Russian life support technology development activities to determine areas of potential long-term application to the U.S. space station; and utilizing the expertise of their space station life support systems to evaluate the benefits to the current U.S. space station program which included the integration of the Russian Mir-1 designs with the U.S. designs to support a crew of six

    A Relativistic Thomas-Fermi Description of Collective Modes in Droplets of Nuclear Matter

    Get PDF
    Isoscalar collective modes in a relativistic meson-nucleon system are investigated in the framework of the time-dependent Thomas-Fermi method. The energies of the collective modes are determined by solving consistently the dispersion relations and the boundary conditions. The energy weighted sum rule satisfied by the model allows the identification of the giant ressonances. The percentage of the energy weighted sum rule exhausted by the collective modes is in agreement with experimental data, but the energies come too high.Comment: 21 pages (RevTex) and 2 postscript figures as a compressed uuencode fil

    UK Head and neck cancer surgical capacity during the second wave of the COVID—19 pandemic: Have we learned the lessons? COVIDSurg collaborative

    Get PDF
    Objectives The aim of this study was to evaluate the differences in surgical capacity for head and neck cancer in the UK between the first wave (March-June 2020) and the current wave (Jan-Feb 2021) of the COVID-19 pandemic. Design REDcap online-based survey of hospital capacity. Setting UK secondary and tertiary hospitals providing head and neck cancer surgery. Participants One representative per hospital was asked to report the capacity for head and neck cancer surgery in that institution. Main outcome measures The principal measures of interests were new patient referrals, capacity in outpatients, theatres and critical care; therapeutic compromises constituting delay to surgery, de-escalated surgery and therapeutic migration to non-surgical primary modality. Results Data were returned from approximately 95% of UK hospitals with a head and neck cancer surgery specialist service. 50% of UK head and neck cancer patients requiring surgery have significantly compromised treatments during the second wave: 28% delayed, 10% have received radiotherapy-based treatment instead of surgery, and 12% have received de-escalated surgery. Surgical capacity has been more severely constrained in the second wave (58% of pre-pandemic level) compared with the first wave (62%) despite the time to prepare. Conclusions Some hospitals are overwhelmed by COVID-19 and unable to offer essential cancer surgery, but all have neighbouring hospitals in their region retaining good (or even normal) capacity. It is noteworthy that very few patients have been appropriately redirected away from the hospitals most constrained by their burden of COVID-19. The paucity of an effective central or regional strategic response to this evident mismatch between demand and surgical capacity is to the detriment of our head and neck cancer patients
    • …
    corecore