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Field studies were conducted over six seasons to determine the critical period for weed control (CPWC) in high-yielding cotton, using common sunflower as a mimic weed. Common sunflower was planted with or after cotton emergence at densities of 1, 2, 5, 10, 20, and 50 plants m−2. Common sunflower was added and removed at approximately 0, 150, 300, 450, 600, 750, and 900 growing degree days (GDD) after planting. Season-long interference resulted in no harvestable cotton at densities of five or more common sunflower plants m−2. High levels of intraspecific and interspecific competition occurred at the highest weed densities, with increases in weed biomass and reductions in crop yield not proportional to the changes in weed density. Using a 5% yield-loss threshold, the CPWC extended from 43 to 615 GDD, and 20 to 1,512 GDD for one and 50 common sunflower plants m−2, respectively. These results highlight the high level of weed control required in high-yielding cotton to ensure crop losses do not exceed the cost of control.
Crop plants have been used as mimic weeds to substitute for real weeds in competition studies. These mimic weeds have the advantages of availability of seed, uniform germination and growth, and the potential to confer better experimental controllability and repeatability. However, the underlying assumption that the competitive effects of mimic weeds are similar to real weeds has not been tested. We compared a range of morphological traits (plant height, node and leaf number, leaf area, leaf size, and dry weight) between the mimic weeds and real weeds: Japanese millet vs. junglerice, mungbean vs. bladder ketmia, and common sunflower vs. fierce thornapple. The impact of these mimic and real weeds on cotton was also assessed. There were similarities and differences between the mimic and real weeds, but impact on cotton lint yield was most closely associated with weed height and dry weight at mid-season. Mimic weeds may be satisfactorily substituted for real weeds in competition experiments where seasonal and environmental conditions are not limiting, such as with fully irrigated cotton, provided the plants have similar dry weight and height at mid-season. Alternatively, one can account for the differences in dry weight and height. We define here a generalized relationship estimating the yield loss of high-yielding, irrigated cotton from weed competition over a range of weed dry weights and heights, allowing extrapolation from the results with mimic weeds to the competitive effects of a range of weeds.
The shape of a distribution of calibrated 14C dates displays spurious peaks and troughs, brought about by changes in the slope of the calibration curve interacting with the spreading effect of the stochastic distribution of counting errors. The distortion results in a positive correlation between the numbers of dates per calendar year and the slopes of the calibration curves, for assemblages of archaeological dates from such widely separated areas as British Columbia, South Australia and New Zealand. The distortion also increases the possibility of date reversals, and increases the overall spread of calibrated 14C dates. After taking into account this systematic distortion and inbuilt age of charcoal and wood samples, we estimate dates for the initial settlement and first appearance of fortifications, and infer a likely trend of population growth for prehistoric New Zealand.
The details of the formation of the first objects, stars and galaxies and their subsequent evolution remain a cosmological unknown. Few observational probes of these processes exist. The Cosmic Infrared Background (CIB) originates from this era and measurements of its anisotropy can provide information to test models of both galaxy evolution and the growth of primordial structure. Such measurements should provide a sensitive probe of the large-scale variation in protogalaxy density at redshifts, z ~ 0.5-3, while optical galaxy surveys provide complementary information at z < 0.5 and Lyman alpha absorption forest studies and Cosmic Microwave Background measurements add information at higher redshifts.
Personalised nutrition (PN) has the potential to reduce disease risk and optimise health and performance. Although previous research has shown good acceptance of the concept of PN in the UK, preferences regarding the delivery of a PN service (e.g. online v. face-to-face) are not fully understood. It is anticipated that the presence of a free at point of delivery healthcare system, the National Health Service (NHS), in the UK may have an impact on end-user preferences for deliverances. To determine this, supplementary analysis of qualitative data obtained from focus group discussions on PN service delivery, collected as part of the Food4Me project in the UK and Ireland, was undertaken. Irish data provided comparative analysis of a healthcare system that is not provided free of charge at the point of delivery to the entire population. Analyses were conducted using the ‘framework approach’ described by Rabiee (Focus-group interview and data analysis. Proc Nutr Soc 63, 655-660). There was a preference for services to be led by the government and delivered face-to-face, which was perceived to increase trust and transparency, and add value. Both countries associated paying for nutritional advice with increased commitment and motivation to follow guidelines. Contrary to Ireland, however, and despite the perceived benefit of paying, UK discussants still expected PN services to be delivered free of charge by the NHS. Consideration of this unique challenge of free healthcare that is embedded in the NHS culture will be crucial when introducing PN to the UK.
The 2005 Gulf Coast hurricane season was one of the most costly and deadly in US history. Hurricane Rita stressed hospitals and led to multiple, simultaneous evacuations. This study systematically identified community factors associated with patient movement out of seven hospitals evacuated during Hurricane Rita.
This study represents the second of two systematic, observational, and retrospective investigations of seven acute care hospitals that reported off-site evacuations due to Hurricane Rita. Participants from each hospital included decision makers that comprised the Incident Management Team (IMT). Investigators applied a standardized interview process designed to assess evacuation factors related to external situational awareness of community activities during facility evacuation due to hurricanes. The measured outcomes were responses to 95 questions within six sections of the survey instrument.
Investigators identified two factors that significantly impacted hospital IMT decision making: (1) incident characteristics affecting a facility's internal resources and challenges; and (2) incident characteristics affecting a facility's external evacuation activities. This article summarizes the latter and reports the following critical decision making points: (1) Emergency Operations Plans (EOP) were activated an average of 85 hours (3 days, 13 hours) prior to Hurricane Rita's landfall; (2) the decision to evacuate the hospital was made an average of 30 hours (1 day, 6 hours) from activation of the EOP; and (3) the implementation of the evacuation process took an average of 22 hours. Coordination of patient evacuations was most complicated by transportation deficits (the most significant of the 11 identified problem areas) and a lack of situational awareness of community response activities. All evacuation activities and subsequent evacuation times were negatively impacted by an overall lack of understanding on the part of hospital staff and the IMT regarding how to identify and coordinate with community resources.
Hospital evacuation requires coordinated processes and resources, including situational awareness that reflects the condition of the community as a result of the incident. Successful hospital evacuation decision making is influenced by community-wide situational awareness and transportation deficits. Planning with the community to create realistic EOPs that accurately reflect available resources and protocols is critical to informing hospital decision making during a crisis. Knowledge of these factors could improve decision making and evacuation practices, potentially reducing evacuation times in future hurricanes.
DowneyEL, AndressK, SchultzCH. External Factors Impacting Hospital Evacuations Caused by Hurricane Rita: The Role of Situational Awareness. Prehosp Disaster Med. 2013;28(3):1-8.
Hurricanes remain a major threat to hospitals throughout the world. The authors attempted to identify the planning areas that impact hospital management of evacuations and the challenges faced when sheltering-in-place.
This observational, retrospective cohort study examined acute care institutions from one hospital system impacted by Hurricane Rita in 2005. Investigators used a standardized survey instrument and interview process, previously used in the hospital evacuation context, to examine hospitals’ initial internal situational awareness and subsequent decision making that resulted in evacuation due to Hurricane Rita. Participants from each hospital included representatives from senior leadership and clinical and nonclinical staff that comprised the Incident Management Team (IMT). The main measured outcomes were responses to 95 questions contained in the survey.
Seven of ten eligible hospitals participated in the study. All facilities evacuated the sickest patients first. The most significant factors prompting evacuation were the issuing of mandatory evacuation orders, storm dynamics (category, projected path, storm surge), and loss of regional communications. Hospitals that sheltered-in-place experienced staff shortages, interruptions to electrical power, and loss of water supplies. Three fully-evacuated institutions experienced understaffing of 40%-60%, and four hospitals sustained depressed staffing levels for over four weeks. Five hospitals lost electricity for a mean of 4.8 days (range .5-11 days). All facilities continued to receive patients to their Emergency Departments (EDs) while conducting their own evacuation.
Hospital EDs should plan for continuous patient arrival during evacuation. Emergency Operation Plans (EOPs) that anticipate challenges associated with evacuation will help to maximize initial decision making and management during a crisis situation. Hospitals that shelter-in-place face critical shortages and must provide independent patient care for prolonged periods.
DowneyEL, AndressK, SchultzCH. Initial Management of Hospital Evacuations Caused by Hurricane Rita: A Systematic Investigation. Prehosp Disaster Med. 2013;28(3):1-7.
A pandemic influenza A(H1N1) 2009 outbreak in a summer school affected 117/276 (42%) students. Residential social contact was associated with risk of infection, and there was no evidence for transmission associated with the classroom setting. Although the summer school had new admissions each week, which provided susceptible students the outbreak was controlled using routine infection control measures (isolation of cases, basic hygiene measures and avoidance of particularly high-risk social events) and prompt treatment of cases. This was in the absence of chemoprophylaxis or vaccination and without altering the basic educational activities of the school. Modelling of the outbreak allowed estimation of the impact of interventions on transmission. These models and follow-up surveillance supported the effectiveness of routine infection control measures to stop the spread of influenza even in this high-risk setting for transmission.
We describe a technique for measuring localization of holes in mid-gap states in high quality a-Si:H devices. The localization of holes is determined by measuring quantum efficiency of a-Si:H devices as a function of reverse bias voltage and wavelength of light. It is shown that the QE of localized holes increases significantly upon application of high electric fields, whereas the QE of de-localized holes does not show such a behavior. The voltage-induced increase in QE is explained using a Frenkel-Poole tunneling model. It is also shown that the density of mid-gap states (states in which holes are localized) increases significantly upon light soaking, and that a major consequence of this increase in mid-gap density is a decrease in the electric field in the device. The decrease in electric field is experimentally estimated by fitting the increased current due to tunneling to the expression for Frenkel-Poole tunneling.
The interdiffusion mechanism in Hg(l-x)X(x)Te/CdTe superlattices where X is Cd, Mn, or Zn can be deduced from the magnitude of the interdiffusion activation energy. By comparing in-situ x-ray diffraction measurements (our work) with results from Tang and Stevenson (J. Vac. Sci. Technol. AS, 1987), it is found that anionic and cationic Frenkel pairs represent the most likely interdiffusion mechanism in Hg(l-x)X(x)Te/CdTe superlattices. This model mixes vacancies and interstitials, as well as maintaining the conduction type and the electronic mobility. It is further shown that interdiffusion sets in as soon as the growth starts.
We examine the role of charged defects in inducing degradation of electronic properties of a-Si:H upon exposure to light. We measure the kinetics of decay of photo-conductivity of a-Si:H films at different light intensities, and the corresponding changes in mid-gap optical absorption. We find that the initial, rapid decay of photo-conductivity can be modeled guite well by invoking Adler's model of conversion of charged defects to neutral dangling bonds(D- to D° conversion). A consequence of this conversion is a decrease in sub-gap absorption upon photo-induced degradation, which we observe. Therefore, we conclude that charged defects coexist with neutral defects in a-Si:H, and they play a major role in early stages of photo-degradation.
The electronic and optical properties of device quality hydrogenated amorphous silicon (a-Si:H) films grown by electron cyclotron resonance (ECR) plasma deposition were studied together with in-situ plasma characteristics. Hydrogen and helium plasmas, excited by 50–250 watts of 2.45 GHz microwave power under ECR conditions, were used to decompose silane at 6 to 20 mtorr pressures during the deposition of a-Si:H films at a 297 C substrate temperature. Both the electron temperature and density, and ion flux are measured near the deposition surface using plane and cylindrical Langmuir probes. An attempt is made to correlate these plasma properties with the light and dark photoconductivity, optical gap, refractive index, and subband gap photoconductivity.
It is generally agreed that the story of the Passion formed a single unit long before there was any attempt to write a consecutive story of the life and teaching of Jesus in the form of a ‘Gospel’. On the other hand the Marcan story presents numerous difficulties and apparent inconsistencies which have often been noted and will concern us in this chapter. Moreover, in the Marcan account we find an alternation between ‘the disciples’ and ‘the Twelve’ up to the point at which they all forsook Jesus and fled, which suggests that there may be in Mark a conflation of at least two sources, the Twelve-source which we have already investigated in the earlier part of Mark, and another which follows the ordinary Marcan usage of referring to ‘the disciples’. From this point onwards we have not this clue to guide us; none the less it seems possible even without this to isolate the two strands of the narrative with a high degree of probability. In this chapter, except in the latter part of (D), the latter part of the trial before Pilate, I print the suggested reconstruction before the discussion of the evidence. Owing to the difficulty of disentangling the originals at this point, the discussion is put first.
The next section (Mark vii. 31—7) at first sight looks like another isolated incident. It stands between the Syrophoenician woman and the doublet version of the miracle of feeding with a very clumsy Marcan introduction. The difficulty of returning from the borders of Tyre and Sidon to the Sea of Galilee via Decapolis (on the eastern shore of the lake) can hardly be explained with Rawlinson ad loc. as due to Mark's desire to locate the second miracle of feeding on Gentile territory; apart from the seven loaves and the seven baskets of remnants, which might or might not suggest the seventy nations of the world, there is nothing to indicate that this miracle is regarded as happening on Gentile ground. The obvious explanation is that the miracle of healing the deaf man was located at Decapolis; the abrupt introduction of viii. 1 and its assumption of a multitude mark it as a miracle story which has no organic connection with its present context. It would seem that Mark's journey is a mere editorial link to bring Jesus from the scene of the healing of the preceding section to the healing of the deaf man for the simple reason that this miracle was in the tradition located in Decapolis.
The story has obvious affinities with two others, the blind man of Bethsaida (viii. 22—6) and Bartimaeus (x. 46—52).