2,032 research outputs found
Breeding uniformity and banking diversity: The genescapes of industrial agriculture, 1935-1970
In the mid-twentieth century, American agriculturists began to fret about a growing threat to key economic crops: the loss or extinction of manifold local varieties, or landraces, resulting from the displacement of these in cultivation by recently introduced varieties that were better
suited for industrial-style agriculture. Many breeders considered diverse landraces to be a valuable, and indeed essential, source of genetic material for their crop improvement efforts - and therefore an essential resource for the very system of agricultural production that appeared to threaten
their continued existence. This paper explores how knowledge of this dilemma - that is, the reliance of industrial agriculture on genetic diversity that it tends to destroy - shaped efforts to conserve biological diversity and simultaneously shaped the landscapes and genescapes of twentieth-century
agriculture. It takes maize (corn) as its central example, as it was changes in the landscapes of maize production, first in the United States and then across Latin America, which spurred an early international collaboration for the preservation of crop genetic diversity. As it shows with
reference to this program and subsequent international developments in the conservation of crop diversity, the technology of the 'seed bank' was considered a crucial addition to the technologies of industrial agricultural production. It was understood to allow breeders to continue responsibly
in the creation of high-yielding but ecologically vulnerable inbred crops by lessening the perceived risks inherent in the un-diverse landscapes of industrial monocrop agriculture.Some of the research for this project was made possible by a grant-in-aid from the Rockefeller Archive Center.This is the author accepted manuscript. The final version is available from White Horse Press via https://doi.org/10.3197/ge.2017.10010
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Atoms in Agriculture
This paper explores the nature of scientific research and innovation at the intersection of technological systems via a study of atomic age plant breeding. I show how the well-established framework of “large technological systems” can be deployed to understand research dynamics in the Cold War life sciences, and further suggest that this framework might be useful in understanding still other areas of scientific research. I argue that the development of experimental tools and research programs dedicated to plant breeding via nuclear-derived technologies arose where researchers experienced the imperatives of innovation within two technological systems—nuclear and agricultural—simultaneously. In the absence of a significant infrastructure for nuclear agriculture, it was the mobility of innovations, the exchange of research tools and practices across experimental settings and research domains, which enabled nuclear-aided plant breeding to flourish for a time. As I show, understanding the dynamics of the technological systems in which researchers were embedded, including their interactions with other systems, is essential to understanding this unlikely area of research inquiry, the novel tools it relied upon, and the unusual scientific careers to which it gave rise.This is the author accepted manuscript. The final version is available from the University of California Press via http://dx.doi.org/10.1525/hsns.2016.46.2.11
Decompression chamber
Exophthalmia, or "pop eye", is a condition currently affecting the deep water fish that inhabit the Oklahoma Aquarium. There are many different ways to treat exophthalmia with the current methods being draining fluid from the fish's eye or removing the eye entirely. Due to a limited budget, the Oklahoma Aquarium has been unable to improve the treatment of this condition from physically removing the fluid to the recommended use of a decompression chamber. Through the use of calculations and modeling, we were able to design a decompression chamber to house an individual fish for treatment of exophthalmia while still keeping to a limited budget. Using a decompression chamber, the Oklahoma Aquarium will be able to treat fish for exophthalmia without having to blind the fish in the process
Validation of learning style measures: implications for medical education practice
It is unclear which learners would most benefit from the more individualised, student-structured, interactive approaches characteristic of problem-based and computer-assisted learning. The validity of learning style measures is uncertain, and there is no unifying learning style construct identified to predict such learners. Objective This study was conducted to validate learning style constructs and to identify the learners most likely to benefit from problem-based and computer-assisted curricula. Methods Using a cross-sectional design, 3 established learning style inventories were administered to 97 post-Year 2 medical students. Cognitive personality was measured by the Group Embedded Figures Test, information processing by the Learning Styles Inventory, and instructional preference by the Learning Preference Inventory. The 11 subscales from the 3 inventories were factor-analysed to identify common learning constructs and to verify construct validity. Concurrent validity was determined by intercorrelations of the 11 subscales. Results A total of 94 pre-clinical medical students completed all 3 inventories. Five meaningful learning style constructs were derived from the 11 subscales: student- versus teacher-structured learning; concrete versus abstract learning; passive versus active learning; individual versus group learning, and field-dependence versus field-independence. The concurrent validity of 10 of 11 subscales was supported by correlation analysis. Medical students most likely to thrive in a problem-based or computer-assisted learning environment would be expected to score highly on abstract, active and individual learning constructs and would be more field-independent. Conclusions Learning style measures were validated in a medical student population and learning constructs were established for identifying learners who would most likely benefit from a problem-based or computer-assisted curriculum.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72443/1/j.1365-2929.2006.02476.x.pd
Decreasing intensity of open-ocean convection in the Greenland and Iceland seas
The air–sea transfer of heat and fresh water plays a critical role in the global climate system. This is particularly true for the Greenland and Iceland seas, where these fluxes drive ocean convection that contributes to Denmark Strait overflow water, the densest component of the lower limb of the Atlantic Meridional Overturning Circulation (AMOC). Here we show that the wintertime retreat of sea ice in the region, combined with different rates of warming for the atmosphere and sea surface of the Greenland and Iceland seas, has resulted in statistically significant reductions of approximately 20% in the magnitude of the winter air–sea heat fluxes since 1979. We also show that modes of climate variability other than the North Atlantic Oscillation (NAO) are required to fully characterize the regional air–sea interaction. Mixed-layer model simulations imply that further decreases in atmospheric forcing will exceed a threshold for the Greenland Sea whereby convection will become depth limited, reducing the ventilation of mid-depth waters in the Nordic seas. In the Iceland Sea, further reductions have the potential to decrease the supply of the densest overflow waters to the AMOC
Light smoking at base-line predicts a higher mortality risk to women than to men; evidence from a cohort with long follow-up
BACKGROUND: There is conflicting evidence as to whether smoking is more harmful to women than to men. The UK Cotton Workers’ Cohort was recruited in the 1960s and contained a high proportion of men and women smokers who were well matched in terms of age, job and length of time in job. The cohort has been followed up for 42 years. METHODS: Mortality in the cohort was analysed using an individual relative survival method and Cox regression. Whether smoking, ascertained at baseline in the 1960s, was more hazardous to women than to men was examined by estimating the relative risk ratio women to men, smokers to never smoked, for light (1–14), medium (15–24), heavy (25+ cigarettes per day) and former smoking. RESULTS: For all-cause mortality relative risk ratios were 1.35 for light smoking at baseline (95% CI 1.07-1.70), 1.15 for medium smoking (95% CI 0.89-1.49) and 1.00 for heavy smoking (95% CI 0.63-1.61). Relative risk ratios for light smoking at baseline for circulatory system disease was 1.42 (95% CI 1.01 to 1.98) and for respiratory disease was 1.89 (95% CI 0.99 to 3.63). Heights of participants provided no explanation for the gender difference. CONCLUSIONS: Light smoking at baseline was shown to be significantly more hazardous to women than to men but the effect decreased as consumption increased indicating a dose response relationship. Heavy smoking was equally hazardous to both genders. This result may help explain the conflicting evidence seen elsewhere. However gender differences in smoking cessation may provide an alternative explanation
Wake up, wake up! It's me! It's my life! patient narratives on person-centeredness in the integrated care context: a qualitative study
Person-centered care emphasizes a holistic, humanistic approach that puts patients first, at the center of medical care. Person-centeredness is also considered a core element of integrated care. Yet typologies of integrated care mainly describe how patients fit within integrated services, rather than how services fit into the patient's world. Patient-centeredness has been commonly defined through physician's behaviors aimed at delivering patient-centered care. Yet, it is unclear how 'person-centeredness' is realized in integrated care through the patient voice. We aimed to explore patient narratives of person-centeredness in the integrated care context
Cost-efficiency assessment of Advanced Life Support (ALS) courses based on the comparison of advanced simulators with conventional manikins
<p>Abstract</p> <p>Background</p> <p>Simulation is an essential tool in modern medical education. The object of this study was to assess, in cost-effective measures, the introduction of new generation simulators in an adult life support (ALS) education program.</p> <p>Methods</p> <p>Two hundred fifty primary care physicians and nurses were admitted to ten ALS courses (25 students per course). Students were distributed at random in two groups (125 each). Group A candidates were trained and tested with standard ALS manikins and Group B ones with new generation emergency and life support integrated simulator systems.</p> <p>Results</p> <p>In group A, 98 (78%) candidates passed the course, compared with 110 (88%) in group B (p < 0.01). The total cost of conventional courses was €7689 per course and the cost of the advanced simulator courses was €29034 per course (p < 0.001). Cost per passed student was €392 in group A and €1320 in group B (p < 0.001).</p> <p>Conclusion</p> <p>Although ALS advanced simulator systems may slightly increase the rate of students who pass the course, the cost-effectiveness of ALS courses with standard manikins is clearly superior.</p
Unified treatment algorithm for the management of crotaline snakebite in the United States: results of an evidence-informed consensus workshop
<p>Abstract</p> <p>Background</p> <p>Envenomation by crotaline snakes (rattlesnake, cottonmouth, copperhead) is a complex, potentially lethal condition affecting thousands of people in the United States each year. Treatment of crotaline envenomation is not standardized, and significant variation in practice exists.</p> <p>Methods</p> <p>A geographically diverse panel of experts was convened for the purpose of deriving an evidence-informed unified treatment algorithm. Research staff analyzed the extant medical literature and performed targeted analyses of existing databases to inform specific clinical decisions. A trained external facilitator used modified Delphi and structured consensus methodology to achieve consensus on the final treatment algorithm.</p> <p>Results</p> <p>A unified treatment algorithm was produced and endorsed by all nine expert panel members. This algorithm provides guidance about clinical and laboratory observations, indications for and dosing of antivenom, adjunctive therapies, post-stabilization care, and management of complications from envenomation and therapy.</p> <p>Conclusions</p> <p>Clinical manifestations and ideal treatment of crotaline snakebite differ greatly, and can result in severe complications. Using a modified Delphi method, we provide evidence-informed treatment guidelines in an attempt to reduce variation in care and possibly improve clinical outcomes.</p
Geographic variation in social organization of Galápagos mockingbirds: ecological correlates of group territoriality and cooperative breeding
To investigate ecological influences on cooperative social organization, I studied the four allopatric species of mockingbirds ( Nesomimus spp.) endemic to the Galápagos archipelago on four islands. On three small, low and arid islands (Genovesa, Champion and Española), mockingbird territories filled all terrestrial habitat, mean group size varied from 4.5 to 14.2 adults, maximum group size ranged from seven to 24 birds, and 70–100% of groups contained more than two birds. San Cristóbal is larger and higher, and it supports a broader range of habitats. At one highland and two coastal sites on this island, mockingbirds did not hold territories in all available habitats, group size averaged 2.2 adults, only 25% of groups were larger than two, and none included more than three adults. Adults dispersed into vacant habitat to establish new territories only on San Cristóbal. Helping behavior has not yet been observed on San Cristóbal, but it occurs on the other three islands. These results support the hypothesis that social groups and cooperative breeding are maintained where limited availability of preferred habitat constrains dispersal. The mechanism relaxing habitat saturation on San Cristóbal, however, remains undetermined. Predation by introduced rats and cats may reduce survival and indirectly reduce group size; these predators are absent from Genovesa, Champion and Española. Differences in food supplies could also affect interand intra-island variation in population density. Variation in social organization among arid coastal sites on the four islands, and similarity between climatically different sites on San Cristóbal, suggest that climatic conditions are less important as determinants of dispersal and breeding. Skews in adult sex ratios also fail to account for inter-island variation in sociality. Although they live in a climatically variable environment, territorial behavior and the physical limits of suitable habitat have an overriding influence on cooperative social organization in Galápagos mockingbirds.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46894/1/265_2004_Article_BF00302932.pd
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