2,263 research outputs found
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Root Growth Dynamics in Response to Moderate Temperatures
Temperature can impact growth in plants though both physical and biological means. Plants physically respond to temperature by scaling their enzyme reaction rate to temperature, such as seen in the redox reactions of photosynthesis. Biologically, a plant can respond to temperature more specifically, such as adjusting its flowering time. Recently, the Baskin lab discovered that cell division in the root of the model plant Arabidopsis thaliana is temperature acclimated (Yang et al., 2017). Between the non-extreme temperatures of 15 and 25˚C cell division and growth zone length are constant. While the rate of cell division increases with temperature, the number of dividing cells decreases, which balances the total production of cells. The length of the growth zone is also temperature acclimated and does not change between moderate temperatures. The core of my dissertation has been working to understand the mechanism, as well as the significance, in the root of temperature acclimated cell division and growth zone length. I have done this by conducting on various genotypes of A. thaliana to determine what genes could be involved in temperature pathways in the root. I also looked at the growth zone length of various genotypes of A. thaliana to determine if this process was dependent on the temperature acclimated cell production rate. I have also been working on looking at these responses in another cell type-the epidermal cells. Finally, I looked at oxygen uptake of four genotypes to determine if temperature acclimated cell production was some type of cost-saving mechanism
A Study of Students\u27 Perception of The Freshman Seminar Course Influence on Academic Persistence and Career Planning
Freshman seminars have become standard in higher education programming. Although there is evidence that these programs are effective in helping the freshman-to-sophomore year persistence rate, there is little research into the specific components of such programs and how they affect academic persistence and career planning. There is also little research on how different students perceive the effectiveness of such programs. This research examined the perceived influence of a freshman seminar on academic persistence and career planning between two student cohorts, a business-major and an undecided-major, via a post-course questionnaire. The student responses between the two cohorts resulted in a significant difference in the overall perceived influence of the freshman seminar on academic persistence and career planning. Additionally, one question pertaining to career planning was found to be significantly different
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Assessing the learning of undergraduate students when using a social justice education game.
Recently, many college administrators have attempted to create a climate on their campuses which emphasizes the importance of valuing all members of the campus community, encouraging diversity of the student population, and educating those who are intolerant of diversity. As a result, many students on our college campuses are resentful and angered by attempts to force feed them information regarding issues of diversity. Such resistance must be considered when planning a curriculum that emphasizes diversity education. The purpose of this study was to determine whether the use of an educational game lessens student resistance toward diversity education while increasing content, behavioral, and attitudinal change. Eighteen participants, a selected group of college students and facilitators, played the game for a 90-minute period, exploring racism and heterosexism during the playing of the game. Pre- and postgame interviews and two follow-up interviews (one week and four to six weeks later) were conducted with each participant. Participants were asked two broad questions: How did participants experience playing the game? This was based on participants\u27 perceptions, my observations during the playing of the game, interviews, and participants\u27 journals. Did playing the game influence the participants\u27 knowledge, awareness, or actions regarding racism and heterosexism, and if so, how
The unexplained nature of reading.
The effects of properties of words on their reading aloud response times (RTs) are 1 major source of evidence about the reading process. The precision with which such RTs could potentially be predicted by word properties is critical to evaluate our understanding of reading but is often underestimated due to contamination from individual differences. We estimated this precision without such contamination individually for 4 people who each read 2,820 words 50 times each. These estimates were compared to the precision achieved by a 31-variable regression model that outperforms current cognitive models on variance-explained criteria. Most (around 2/3) of the meaningful (non-first-phoneme, non-noise) word-level variance remained unexplained by this model. Considerable empirical and theoretical-computational effort has been expended on this area of psychology, but the high level of systematic variance remaining unexplained suggests doubts regarding contemporary accounts of the details of the mechanisms of reading at the level of the word. Future assessment of models can take advantage of the availability of our precise participant-level database
Lead Us Not Into (Unwarranted) Temptation: A Proposal to Replace the Entrapment Defense With a Reasonable-Suspicion Requirement
Interactive Search and Exploration in Online Discussion Forums Using Multimodal Embeddings
In this paper we present a novel interactive multimodal learning system,
which facilitates search and exploration in large networks of social multimedia
users. It allows the analyst to identify and select users of interest, and to
find similar users in an interactive learning setting. Our approach is based on
novel multimodal representations of users, words and concepts, which we
simultaneously learn by deploying a general-purpose neural embedding model. We
show these representations to be useful not only for categorizing users, but
also for automatically generating user and community profiles. Inspired by
traditional summarization approaches, we create the profiles by selecting
diverse and representative content from all available modalities, i.e. the
text, image and user modality. The usefulness of the approach is evaluated
using artificial actors, which simulate user behavior in a relevance feedback
scenario. Multiple experiments were conducted in order to evaluate the quality
of our multimodal representations, to compare different embedding strategies,
and to determine the importance of different modalities. We demonstrate the
capabilities of the proposed approach on two different multimedia collections
originating from the violent online extremism forum Stormfront and the
microblogging platform Twitter, which are particularly interesting due to the
high semantic level of the discussions they feature
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Humanism in the Age of COVID-19: Renewing Focus on Communication and Compassion
The global COVID-19 pandemic has become one of the largest clinical and operational challenges faced by emergency medicine, and our EDs continue to see increased volumes of infected patients, many of whom are not only ill, but acutely aware and fearful of their circumstances and potential mortality. Given this, there may be no more important time to focus on staff-patient communication and expression of compassion.However, many of the techniques usually employed by emergency clinicians to provide comfort to patients and their families are made more challenging or impossible by the current circumstances. Geriatric ED patients, who are at increased risk of severe disease, are particularly vulnerable to the effects of isolation.Despite many challenges, emergency clinicians have at their disposal a myriad of tools that can still be used to express compassion and empathy to their patients. Placing emphasis on using these techniques to maximize humanism in the care of COVID-19 patients during this crisis has the potential to bring improvements to ED patient care well after this pandemic has passed
Design of Stainless Steel Sections Against Distortional Buckling
Current cold-formed stainless steel design codes for distortional buckling, including the Australian/New Zealand Standard AS/NZS 4673 (2001) and the North American ASCE (2002), have been based on cold-formed carbon steel codes without the support or corroboration of experimental evidence. As such, an experimental program on the distortional buckling of axially compressed, cold-formed stainless steel simple lipped channels and lipped channels with intermediate stiffeners was conducted. Results show that the effect of stainless steel material non-linearity is partially negated by the strength-enhanced corners, and this becomes evident in the design evaluation. Both the effective width and the direct strength (ASINZS 4600 1996) design approaches are considered. When the enhanced corner properties are ignored, the effective width design evaluation may become unconservative for sections with a corner area less than 10% of the gross area and become overly conservative for sections with a corner area greater than approximately 10% of the gross area. The direct strength evaluation provides reasonably conservatively strength predictions for sections with a corner area of at least 10% of the gross area, provided enhanced corners are ignored and the (actual) fixed end conditions are modeled in the elastic buckling analysis
Experimental Investigation of Distortional Buckling of Cold-Formed Stainless Steel Sections
This paper describes the experimental investigation of the distortional buckling of thin-walled stainless steel sections in compression. Austenitic 304, ferritic 430 stainless steel and ferritic-like 3Crl2 chromium weldable steel sheets were brake-pressed into simple-lipped channels and simple-lipped channels with intermediate stiffeners. A comprehensive procedure to determine the mechanical properties of stainless steel material is described. A total of 19 distortional tests failed at stresses greater than the proportionality stress, and hence were influenced by material non-linearity. Data required to assess current design guidelines in place for distortional buckling of stainless steel compression members are provided herein
A coding theory foundation for the analysis of general unconditionally secure proof-of-retrievability schemes for cloud storage
There has been considerable recent interest in “cloud storage” wherein a user asks a server to store a large file. One issue is whether the user can verify that the server is actually storing the file, and typically a challenge-response protocol is employed to convince the user that the file is indeed being stored correctly. The security of these schemes is phrased in terms of an extractor which will recover or retrieve the file given any “proving algorithm” that has a sufficiently high success probability. This paper treats proof-of-retrievability schemes in the model of unconditional security, where an adversary has unlimited computational power. In this case retrievability of the file can be modelled as error-correction in a certain code. We provide a general analytical framework for such schemes that yields exact (non-asymptotic) reductions that precisely quantify conditions for extraction to succeed as a function of the success probability of a proving algorithm, and we apply this analysis to several archetypal schemes. In addition, we provide a new methodology for the analysis of keyed POR schemes in an unconditionally secure setting, and use it to prove the security of a modified version of a scheme due to Shacham and Waters [Lecture Notes in Comput. Sci. 5350, Springer (2008), 90–107] under a slightly restricted attack model, thus providing the first example of a keyed POR scheme with unconditional security. We also show how classical statistical techniques can be used to evaluate whether the responses of the prover are accurate enough to permit successful extraction. Finally, we prove a new lower bound on storage and communication complexity of POR schemes.
This paper treats proof-of-retrievability schemes in the model of unconditional security, where an adversary has unlimited computational power. In this case retrievability of the file can be modelled as error-correction in a certain code. We provide a general analytical framework for
such schemes that yields exact (non-asymptotic) reductions that precisely quantify conditions for extraction to succeed as a function of the success probability of a proving algorithm, and we apply this analysis to several archetypal schemes. In addition, we provide a new methodology for the analysis of keyed POR schemes in an unconditionally secure setting, and use it to prove the
security of a modified version of a scheme due to Shacham and Waters under a slightly restricted attack model, thus providing the first example of a keyed POR scheme with unconditional security. We also show how classical statistical techniques can be used to evaluate whether the
responses of the prover are accurate enough to permit successful extraction. Finally, we prove a new lower bound on storage and communication complexity of POR schemes
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