2,530 research outputs found
Optimal Harvest Time of Florida Valencia Oranges to Maximize Grower Returns
Research goals are to estimate the optimal harvest time of Florida Valencia oranges for Florida growers and calculate the economic consequences of harvesting inside or outside the optimal window. Determining the optimal fruit harvest time will help the industry anticipate how mechanical harvesting may affect deviations from this optimum.Crop Production/Industries,
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Using electronic surveys: advice from survey professionals
The study reports the perceptions and recommendations of sixty-two experienced survey researchers from the American Educational Research Association regarding the use of electronic surveys. The most positive aspects cited for the use of electronic surveys were reduction of costs (i.e., postage, phone charges), the use of electronic mail for pre-notification or follow-up purposes, and the compatibility of data with existing software programs. These professionals expressed limitations in using electronic surveys pertaining to the limited sampling frame as well as issues of confidentiality, privacy, and the credibility of the sample. They advised that electronic surveys designed with the varied technological background and capabilities of the respondent in mind, follow sound principles of survey construction, and be administered to pre-notified, targeted populations with published email addresses. Accessed 73,957 times on https://pareonline.net from January 02, 2002 to December 31, 2019. For downloads from January 1, 2020 forward, please click on the PlumX Metrics link to the right
Deep Sleep and Parietal Cortex Gene Expression Changes Are Related to Cognitive Deficits with Age
BACKGROUND: Age-related cognitive deficits negatively affect quality of life and can presage serious neurodegenerative disorders. Despite sleep disruption\u27s well-recognized negative influence on cognition, and its prevalence with age, surprisingly few studies have tested sleep\u27s relationship to cognitive aging.
METHODOLOGY: We measured sleep stages in young adult and aged F344 rats during inactive (enhanced sleep) and active (enhanced wake) periods. Animals were behaviorally characterized on the Morris water maze and gene expression profiles of their parietal cortices were taken.
PRINCIPAL FINDINGS: Water maze performance was impaired, and inactive period deep sleep was decreased with age. However, increased deep sleep during the active period was most strongly correlated to maze performance. Transcriptional profiles were strongly associated with behavior and age, and were validated against prior studies. Bioinformatic analysis revealed increased translation and decreased myelin/neuronal pathways.
CONCLUSIONS: The F344 rat appears to serve as a reasonable model for some common sleep architecture and cognitive changes seen with age in humans, including the cognitively disrupting influence of active period deep sleep. Microarray analysis suggests that the processes engaged by this sleep are consistent with its function. Thus, active period deep sleep appears temporally misaligned but mechanistically intact, leading to the following: first, aged brain tissue appears capable of generating the slow waves necessary for deep sleep, albeit at a weaker intensity than in young. Second, this activity, presented during the active period, seems disruptive rather than beneficial to cognition. Third, this active period deep sleep may be a cognitively pathologic attempt to recover age-related loss of inactive period deep sleep. Finally, therapeutic strategies aimed at reducing active period deep sleep (e.g., by promoting active period wakefulness and/or inactive period deep sleep) may be highly relevant to cognitive function in the aging community
Kanamycin resistance during in vitro development of pollen from transgenic tomato plants
Effects of kanamycin on pollen germination and tube growth of pollen from non-transformed plants and from transgenic tomato plants containing a chimaeric kanamycin resistance gene were determined. Germination of pollen was not affected by the addition of kanamycin to the medium in both genotypes. Kanamycin, however, severely affected tube growth of pollen from non-transformed plants, while pollen from plants containing the chimaeric gene were less sensitive and produced significantly longer tubes at kanamycin concentrations between 200-400 mg l-1. Apparently, this resistance for kanamycin correlates with the expression of the chimaeric gene during male gametophytic development.
Exploring Racism in Health Pedagogy
Utilizing a classroom incident that prompted formal public and informal private conversations about race across the campus of a New England regional comprehensive university, we suggest that the discussion of race in public health and health promotion is often compartmentalized. The pedagogy of public health and health promotion often examines race in terms of health disparities, access to health care, cultural sensitivity and competence among public health providers. While this examination is applauded, it does not adequately confront racism and the experience of race by students in actual public health classrooms. Race, we argue, appears theoretical and does not acknowledge the lived experiences of students in the classrooms and is without a discussion of whiteness or white supremacy. This piece explores a classroom approach to engage the topic of race through an examination of whiteness in order to inform future pedagogy and professional practice. We suggest that public health in both professional practice and as an academic discipline requires confronting white supremacy and racism not only in pedagogy but in course content, faculty development, and administration. We conclude that it is ineffective to merely embrace racial diversity without being anti-racist
CBTL Design Case Summary Conventional Feedstock Supply System - Herbaceous
A conventional bale feedstock design has been established that represents supply system technologies, costs, and logistics that are achievable today for supplying herbaceous feedstocks as a blendstock with coal for energy production. Efforts are made to identify bottlenecks and optimize the efficiency and capacities of this supply system, within the constraints of existing local feedstock supplies, equipment, and permitting requirements. The feedstock supply system logistics operations encompass all of the activities necessary to move herbaceous biomass feedstock from the production location to the conversion reactor ready for blending and insertion. This supply system includes operations that are currently available such that costs and logistics are reasonable and reliable. The system modeled for this research project includes the uses of field-dried corn stover or switchgrass as a feedstock to annually supply an 800,000 DM ton conversion facility
Nanoscale Equilibrium Crystal Shapes
The finite size and interface effects on equilibrium crystal shape (ECS) have
been investigated for the case of a surface free energy density including step
stiffness and inverse-square step-step interactions. Explicitly including the
curvature of a crystallite leads to an extra boundary condition in the solution
of the crystal shape, yielding a family of crystal shapes, governed by a shape
parameter c. The total crystallite free energy, including interface energy, is
minimized for c=0, yielding in all cases the traditional PT shape (z x3/2).
Solutions of the crystal shape for c≠0 are presented and discussed in the
context of meta-stable states due to the energy barrier for nucleation.
Explicit scaled relationships for the ECS and meta-stable states in terms of
the measurable step parameters and the interfacial energy are presented.Comment: 35 page
Exploring face perception in disorders of development: evidence from Williams syndrome and autism
Individuals with Williams syndrome (WS) and autism are characterized by different social phenotypes but have been said to show similar atypicalities of face-processing style. Although the structural encoding of faces may be similarly atypical in these two developmental disorders, there are clear differences in overall face skills. The inclusion of both populations in the same study can address how the profile of face skills varies across disorders. The current paper explored the processing of identity, eye-gaze, lip-reading, and expressions of emotion using the same participants across face domains. The tasks had previously been used to make claims of a modular structure to face perception in typical development. Participants with WS (N=15) and autism (N=20) could be dissociated from each other, and from individuals with general developmental delay, in the domains of eye-gaze and expression processing. Individuals with WS were stronger at these skills than individuals with autism. Even if the structural encoding of faces appears similarly atypical in these groups, the overall profile of face skills, as well as the underlying architecture of face perception, varies greatly. The research provides insights into typical and atypical models of face perception in WS and autism
Co-Eruptive Tremor from Bogoslof Volcano: Seismic Wavefield Composition at Regional Distances
We analyze seismic tremor recorded during eruptive activity over the course of the 2016–2017 eruption of Bogoslof volcano, Alaska. Only regional recordings of the tremor wavefield exist for Bogoslof, making it a challenge to place the recordings in context with other eruptions that are normally captured by local seismic data. We apply a technique of time-frequency polarization analysis to three-component seismic data to reveal the wavefield composition of Bogoslof eruption tremor.We find that at regional distances, the tremor is dominated by P-waves in the band from 1.5 to 10 Hz. Using this information, along with an enriched Bogoslof earthquake catalog, we obtain estimates of average reduced displacement (DR) for eruption tremor during 25 of the 70 Bogoslof events. DR reaches as high as approximately 40 cm2 for two of the major events, similar to other VEI~3 eruptions in Alaska. Overall, average reduced displacement displays a weak correlation to plume height during the first half of the 9-month-long eruption sequence, with a few notable exceptions. The two events with the highest DR values also generated measurable eruption tremor at very-long-periods (VLP) between 0.05 and 0.15 Hz
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