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ZhouZitaoChemBioEnvironEnginInfluenceSurfaceChemicalSupportingInfoFile5.xlsx
No full textZinc oxide nanoparticles (ZnO NPs) are widely used in a variety of products, thus understanding their health and environmental impacts is necessary to appropriately manage their risks. To keep pace with the rapid increase in products utilizing engineered ZnO NPs, rapid in silico toxicity test methods based on knowledge of comprehensive in vivo and in vitro toxic responses are beneficial in determining potential nanoparticle impacts. To achieve or enhance their desired function, chemical modifications are often performed on the NPs surface; however, the roles of these alterations play in determining the toxicity of ZnO NPs are still not well understood. As such, we investigated the toxicity of 17 diverse ZnO NPs varying in both size and surface chemistry to developing zebrafish (exposure concentrations ranging from 0.016 to 250 mg/L). Despite assessing a suite of 19 different developmental, behavioural and morphological endpoints in addition to mortality in this study, mortality was the most common endpoint observed for all of the ZnO NP types tested. ZnO NPs with surface chemical modification, regardless of the type, resulted in mortality at 24 hours post-fertilization (hpf) while uncoated particles did not induce significant mortality until 120 hpf. Using eight intrinsic chemical properties that relate to the outermost surface chemistry of the engineered ZnO nanoparticles, the highly dimensional toxicity data were converted to a 2-dimensional data set through principal component analysis (PCA). Euclidean distance was used to partition different NPs into several groups based on converted data (score) which were directly related to changes in the outermost surface chemistry. Kriging estimations were then used to develop a contour map based on mortality data as a response. This study illustrates how the intrinsic properties of NPs, including surface chemical modifications and capping agents, are useful to separate and identify ZnO NP toxicity to zebrafish (Danio rerio).Keywords: nanotechnology, modelling, toxicology, nanomaterials, kriging estimationKeywords: nanotechnology, modelling, toxicology, nanomaterials, kriging estimatio
Lifetime Reproductive Effort
Full text linkIn a 1966 American Naturalist article, G. C. Williams
initiated the study of reproductive effort (RE) with the prediction
that longer-lived organisms ought to expend less in reproduction per
unit of time. We can multiply RE, often measured in fractions of
adult body mass committed to reproduction per unit time, by the
average adult life span to get lifetime reproductive effort (LRE).
Williams’s hypothesis (across species, RE decreases as life span increases)
can then be refined to read “LRE will be approximately
constant for similar organisms.” Here we show that LRE is a key
component of fitness in nongrowing populations, and thus its value
is central to understanding life-history evolution. We then develop
metabolic life-history theory to predict that LRE ought to be approximately
1.4 across organisms despite extreme differences in production
and growth rates. We estimate LRE for mammals and lizards
that differ in growth and production by five- to tenfold. The distributions
are approximately normal with means of 1.43 and 1.41 for
lizards and mammals, respectively (95% confidence intervals: 1.3–
1.5 and 1.2–1.6). Ultimately, therefore, a female can only produce a
mass of offspring approximately equal to 1.4 times her own body
mass during the course of her life.This is the publisher’s final pdf. The published article is copyrighted by University of Chicago Press and can be found at: http://www.press.uchicago.edu/ucp/journals/journal/an.html.Keywords: Williams’s hypothesis, lizards, dimensionless, life-history optimization, mammalsKeywords: Williams’s hypothesis, lizards, dimensionless, life-history optimization, mammal
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No full textThis thesis is an effort to formalize and document some of the changes occuring in the Warwar Valley of Gongola State, Nigeria, West Africa. The documentation will comprise a photographic study over time accompanied by an ethnographic narrative. Information gathered from photographic images, field notes and the anthropological record will then be applied to a cultural-ecological model based on the theory of Julian Steward. The Mambilla people inhabiting the Warwar Valley are changing their traditional agricultural land use patterns and value system due to the influx of new ideas, notably the introduction of a cash economy. This cultural change has affected environmental change, observable in soil erosion
Effects of two environmental best management practices on pond water and effluent quality and growth of Nile tilapia, Oreochromis niloticus
Full text linkThe trajectory of aquaculture growth in sub-Saharan Africa has necessitated closer attention to the use of environmental best management practices (BMPs). Two BMPs in particular, water reuse and floating feeds, are being promoted for adoption by pond fish farmers in sub-Saharan Africa. In this study, we investigated: (1) the effect of water source and feed type on water quality; (2) the effect of water source and feed type on tilapia growth; and (3) the quality of potential effluents from ponds using different water source and feed types. The study was conducted in Ghana using on-farm experiments involving monitoring of water quality and growth of Nile tilapia Oreochromis niloticus for 160 days. Although considered low-intensity production systems, nutrients and solids in the study ponds exceeded levels expected in intensive culture ponds by wide margins, whereas BOD₅ was within the range for semi-intensive ponds. Floating feed was associated with higher water quality, especially dissolved oxygen, and higher growth, but water source did not significantly affect growth. Water reuse appears to be a viable BMP for sustainable aquaculture in the region, but the use of floating feed as BMP will depend on the economic profitability of floating feed use.This is the publisher’s final pdf. The published article is copyrighted by the author(s) and published by MDPI. The published article can be found at: http://www.mdpi.com/journal/sustainability.Keywords: Water quality, Fish production, Floating feeds, Environmental assessment, Sub-Saharan Africa, Water reuse, Aquaculture, Ghana, Tilapia, Effluent, BMPsKeywords: Water quality, Fish production, Floating feeds, Environmental assessment, Sub-Saharan Africa, Water reuse, Aquaculture, Ghana, Tilapia, Effluent, BMP
O'MalleyRobertBotanyPlantPathologyGeostationarySatelliteObservations.pdf
No full textSince June 2010, the Geostationary Ocean Color Imager (GOCI) has been collecting the first
diurnally resolved satellite ocean measurements. Here GOCI retrievals of phytoplankton chlorophyll
concentration and fluorescence are used to evaluate daily to seasonal changes in photophysiological
properties. We focus on nonphotochemical quenching (NPQ) processes that protect phytoplankton from
high light damage and cause strong diurnal cycles in fluorescence emission. This NPQ signal varies
seasonally, with maxima in winter and minima in summer. Contrary to expectations from laboratory studies
under constant light conditions, this pattern is highly consistent with an earlier conceptual model and recent
field observations. The same seasonal cycle is registered in fluorescence data from the polar-orbiting
Moderate Resolution Imaging Spectroradiometer Aqua satellite sensor. GOCI data reveal a strong correlation
between mixed layer growth irradiance and fluorescence-derived phytoplankton photoacclimation state that
can provide a path for mechanistically accounting for NPQ variability and, subsequently, retrieving information
on iron stress in global phytoplankton populations.Keywords: GOCI fluorescence, Phytoplankton, NPQ effectsKeywords: GOCI fluorescence, Phytoplankton, NPQ effectsKeywords: GOCI fluorescence, Phytoplankton, NPQ effectsKeywords: GOCI fluorescence, Phytoplankton, NPQ effect
Competencies needed in off-farm agriculture based on a survey of agricultural industry in the Vale area
Full text linkAgricultural education is emphasizing all phases of agriculture in an attempt to help provide sufficient numbers of trained employees for agricultural industry. This is reflected by areas of instruction encompassing production and off-farm agriculture. Students receive supervision in production and occupational experience at home and with local off-farm agricultural business firms. The purpose of this study was to determine a core of competencies and related information about which group instruction may be given. The purpose of such instruction is preparing a student for selecting and advancing in an agricultural occupation of his choice. Businesses were consulted in the geographical area of Vale, Nyssa, and Ontario, Oregon to determine the need for employees with an agricultural background. One-third of the firms were interviewed personally to determine general competencies looked for in agricultural employees. The study revealed that students with an agricultural background are in demand. Most off-farm agricultural occuptaions (now and future) are located with farm machinery, feed, seed, fertilizer and chemical and ornamental horticultural firms. This study revealed that 61.12 percent of all employees in the Vale area need an agricultural background. Training in vocational agriculture provides desirable background experience for employment in most firms, Farm work experience was rated as essential by a majority of the firms interviewed. Production agriculture should be the core program to provide basis for experiences needed to successfully enter and advance in an off-farm agricultural occupation. Close cooperation should be established with farm machinery, fertilizer and chemical firms as they provide the largest number of employment opportunities now and anticipated in the future. These firms also provide opportunity for cooperative work training experience during seasonal rush periods as do service stations and food stores. The competencies of most concern to employers interviewed, and around which instruction should be developed, were those involving human relations and salesmanship
LiPeripartalRumenProtected.pdf
No full textBackground: Main objectives were to determine to what extent Smartamine M (SM) supplementation to a prepartal higher-energy diet could alter neutrophil (PMN) and liver tissue immunometabolic biomarkers, and whether those responses were comparable to those in cows fed a prepartal lower-energy diet (CON).
Results: Twenty-eight multiparous Holstein cows were fed CON (NE[subscript]L = 1.24 Mcal/kg DM) during d −50 to d −22 relative to calving. From d −21 to calving, cows were randomly assigned to a higher-energy diet (OVE, n = 9; NE[subscript]L = 1.54 Mcal/kg DM), OVE plus SM (OVE + SM, n = 10; SM= 0.07 % of DM) or remained on CON (n = 9). All cows received the same basal lactation diet (NE[subscript]L = 1.75 Mcal/kg DM). Supplementation of SM (OVE + SM) continued until 30 d postpartum. Liver biopsies were harvested at d −10, 7, and 21 relative to parturition. Blood PMN isolated at −10, 3, and 21 d relative to calving was used to evaluate gene expression. As expected, OVE increased liver lipid content postpartum; however, cows fed OVE + SM or CON had lower concentrations than OVE. Compared with OVE, cows in CON and OVE + SM had
greater DMI postpartum and milk production. Furthermore, cows fed OVE + SM had the greatest milk protein and fat percentage and lowest milk SCC despite having intermediate PMN phagocytic capacity. Adaptations in PMN gene expression in OVE + SM cows associated with the lower SCC were gradual increases from −10 to 21 d in genes that facilitate migration into inflammatory sites (SELL, ITGAM), enzymes essential for reducing reactive oxygen metabolites (SOD1, SOD2), and a transcription factor(s) required for controlling PMN development (RXRA). The greater expression of TLR4 on d 3, key for activation of innate immunity due to inflammation, in OVE compared with CON cows suggests a more pronounced inflammatory state. Feeding OVE + SM dampened the upregulation of TLR4, despite the fact that these cows had similar expression of the pro-inflammatory genes NFKB1 and TNF as OVE. Cows in CON had lower overall expression of these inflammation-related genes and GSR, which generates reduced glutathione, an important cellular antioxidant.
Conclusions: Although CON cows appeared to have a less stressful transition into lactation, SM supplementation was effective in alleviating negative effects of energy-overfeeding. As such, SM was beneficial in terms of production and appeared to boost the response of PMN in a way that improved overall cow health.Keywords: Methionine, Blood neutrophil, Gene expressionKeywords: Methionine, Blood neutrophil, Gene expressio
Diel Feeding Chronology, Gastric Evacuation, and Daily Food Consumption of Juvenile Chinook Salmon in Oregon Coastal Waters
Full text linkThe diel feeding periodicity of juvenile Chinook salmon Oncorhynchus tshawytscha was determined from stomachs collected in coastal waters off Oregon in 2000 and 2003. Juvenile Chinook salmon exhibited a diurnal feeding pattern with morning and evening feeding periods. There were differences in the duration and magnitude of the dawn and dusk peaks between the 2 years. Gastric evacuation rates of euphausiid meals were estimated from laboratory experiments at 9.3, 10.7, and 13.9 degree C. Based on an exponential model, the instantaneous evacuation rates at these three temperatures were 0.0407, 0.0589, and 0.0807 per hour, respectively. The daily ration of juvenile Chinook salmon in Oregon coastal waters in 2000 and 2003 was estimated using three models. Using laboratory-derived evacuation rates, the Elliott and Persson and Eggers models produced daily ration estimates of 2.04% and 2.57% of body weight (BW), respectively, in 2000 and 2.93% and 2.46%BW in 2003. The MAXIMS model, which does not rely on laboratory-derived evacuation rates, produced higher estimates of daily ration (3.84% and 4.28%BW). Our diel feeding chronology, gastric evacuation rate, and daily ration estimates for juvenile Chinook salmon were comparable to those of other juvenile salmonids.Keywords: temperature effects, Oncorhynchus tshawytscha, food consumption, juvenilesKeywords: temperature effects, Oncorhynchus tshawytscha, food consumption, juvenile
Appendix Video 3.12.avi
No full textAccurate chromosome segregation and cell cleavage are critical to maintaining genomic integrity. Both events involve the spindle apparatus, but the exact mechanics is as puzzling as the contradicting models proposed in the last two centuries. In this dissertation, current prevailing models of chromosome segregation and cell cleavage are tested using a newly-developed Multimode Microsurgery and Imaging System. The system permits remodeling of the spindle structure in testing the current models and proposing new theories.
The mechanics of chromosome segregation is a process coupled to the shortening of kinetochore microtubules (kMTs). Which end shortens and whether the shortening provides poleward forces remain unsolved, since depolymerization may occur at the plus ends by ‘Pac-Man’ activities of a kinetochore and/or the minus ends by Poleward Flux of microtubules (Traction Fibers). Alternatively, the shortening may be secondary to the force-generating Spindle Matrix and/or the non-kMTs. I differentiated these models in grasshopper spermatocytes by revealing dynamics of laser-severed kMTs both in and outside the context of the spindle. I found that the kMTs dynamically maintain their length by poleward flux, polymerizing at the plus ends while depolymerizing at the minus ends without net shortening. Poleward forces are generated when net-shortening of the kMTs occurs at the spindle poles, ‘reeling in’ the attached chromosomes.
The mechanics of cleavage furrow induction is a process mediated by spindle microtubules and associated proteins, arguably via Polar Relaxation or Equatorial Stimulation mechanisms. By manipulating distribution of actin filaments in silkworm spermatocytes, I show that ‘relaxation’ can be induced at any region of the cell cortex by any microtubules mechanically brought nearby. The relaxation causes exclusion of cortical actin filaments, which depends on microtubule dynamics but not RhoA activity. ‘Stimulation’ can also be induced at any region of the cell cortex by the plus ends of central spindle microtubules brought nearby. The stimulation occurs as rapid de novo assembly of actin patches at the microtubule overlap and their lateral transport to the cortex, both of which depend on RhoA activity but not microtubule dynamics. I conclude that polar relaxation and equatorial stimulation coexist in cytokinesis, providing cell cleavage with ‘double insurance.
