1,854 research outputs found
Contextual queries and situated information needs for mobile users
The users of mobile devices increasingly use networked services to address their information needs. Questions asked by mobile users are strongly influenced by contextual factors such as location, conversation and activity. We report on a diary study performed to better understand mobile information needs.
Participantsâ diary entries are used as a basis for discussing the geographical and situational context in which mobile information behaviour occurs. The suitability of user queries to be answered by a portable knowledge collection and web search are also considered.
We find that the type of questions recorded by participants varies across their locations, with differences between home, shopping and in-car contexts. These variations occur both in the query terms and in the form of desired answers. Both the location of queries and the participantsâ activities affected participantsâ questions. When information needs were affected by both location and activity, they tended to be strongly affected by both factors. The overall picture that emerges is one of multiple contextual influences interacting to shape mobile information needs. Mobile devices that attempt to adapt to usersâ context will need to account for a rich variety of situational factors
Contextual queries express mobile information needs
The users of mobile devices increasingly use networked services to address their information needs. Questions asked by mobile users are strongly influenced by contextual factors such as location, conversation and activity. We report on a diary study performed to better understand mobile information needs. We find that the type of questions recorded by participants varies across their locations, with differences between home, shopping and in-car contexts. These variations occur both in the query terms and in the form of desired answers. Both the location of queries and the participants' activities affected participants' questions. When information needs were affected by both location and activity, they tended to be strongly affected by both factors. The overall picture that emerges is one of multiple contextual influences interacting to shape mobile information needs. Mobile devices that attempt to adapt to users' context will need to account for a rich variety of situational factors
Sufficient conditions for unique global solutions in optimal control of semilinear equations with nonlinearity
We consider a semilinear elliptic optimal control problem possibly
subject to control and/or state constraints. Generalizing previous work we
provide a condition which guarantees that a solution of the necessary first
order conditions is a global minimum. A similiar result also holds at the
discrete level where the corresponding condition can be evaluated explicitly.
Our investigations are motivated by G\"unter Leugering, who raised the question
whether our previous results can be extended to the nonlinearity
. We develop a corresponding analysis and present several
numerical test examples demonstrating its usefulness in practice
Control of apple scab by curative applications of biocontrol agents
In organic apple growing protective applications with copper, sulphur or lime sulphur are
used for apple scab control. Protective applications have to be repeated when new leaves
unfold. The timing of protective sprays depends on the weather forecast. If forecasted
infection conditions fail to appear, treatments were for nothing. With curative control
agents available, the number of treatments could be reduced. In greenhouse trials we
tested control agents for their protective and curative efficiency against apple scab after
artificial inoculation of potted apple trees. Applications were done 2 hours before
inoculation, 5 hours after inoculation on wet leaves, 5 hours after inoculation during
simulated rainfall or 24 hours after inoculation on wet or dry leaves. The optimal time of
application differed between the preparations tested. Vitisan and OmniProtect had their
highest activity when sprayed curative 24 hours after inoculation. Combinations were
found, which revealed a high efficiency against apple scab from 2h before to 24 hours after
inoculation. In a field trial apple scab was effectively controlled by curative applications of
OmniProtect
Fast iterative solution of reaction-diffusion control problems arising from chemical processes
PDE-constrained optimization problems, and the development of preconditioned iterative methods for the efficient solution of the arising matrix system, is a field of numerical analysis that has recently been attracting much attention. In this paper, we analyze and develop preconditioners for matrix systems that arise from the optimal control of reaction-diffusion equations, which themselves result from chemical processes. Important aspects in our solvers are saddle point theory, mass matrix representation and effective Schur complement approximation, as well as the outer (Newton) iteration to take account of the nonlinearity of the underlying PDEs
Regularization-robust preconditioners for time-dependent PDE constrained optimization problems
In this article, we motivate, derive and test ïżœeffective preconditioners to be used with the Minres algorithm for solving a number of saddle point systems, which arise in PDE constrained optimization problems. We consider the distributed control problem involving the heat equation with two diffïżœerent functionals, and the Neumann boundary control problem involving Poisson's equation and the heat equation. Crucial to the effïżœectiveness of our preconditioners in each case is an effïżœective approximation of the Schur complement of the matrix system. In each case, we state the problem being solved, propose the preconditioning approach, prove relevant eigenvalue bounds, and provide numerical results which demonstrate that our solvers are effïżœective for a wide range of regularization parameter values, as well as mesh sizes and time-steps
A Follow-up of Decision Changes from the ACT Profile for Freshmen at USU
Decision making and decision changes were studied in late adolescents regarding post-high school choices. A branching questionnaire was constructed and mailed to 1239 late adolescents who during the preceding year had indicated on the American College Test (ACT) that Utah State University (USU) was their first choice for college attendance, but whose names did not appear on the USU Registrar\u27s list of enrolled freshmen, Fall 1969. 62% of the questionnaires were returned. Questions were asked concerning post-high school decision making and decision change: What alternatives to attendance at USU were chosen? Was the alternative chosen college-related or was the change made to a non-college alternative? Who most influenced the decision to change alternatives? Was the change of decision permanent or was future attendance at USU planned? What factors were most important and least important in making the decision to change to a college-related alternative? What factors were most important and least important in making the decision to change to a non-college alternative? Were future plans, following the present course of action, decided or undecided? What effect did location have on college decision plans? To what extent were the college decision changes rational?
It was found that the 768 late adolescents who changed their decision to attend USU in the fall of 1969, chose a variety of alternative courses of action. Nearly half of these Ss chose to attend another college or university, while another one fourth chose to enroll at USU at a later date. Thus, nearly three fourths of the Ss remained within the domain of their original decision, that being to attend college. The Ss most often saw themselves as being the primary influencers of their decisions, with friends and fathers being less frequently mentioned influencers. Religious advisors, recruiters, and employers were least frequent primary influencers. It was seen that nearly 4d% of the decision changes not to enroll at USU were permanent, while another approximate 40% were temporary -- the Ss having already enrolled or planning to enroll at USU in the future. Expenses, location, and financial aid were the leading factors determining college choice, and housing, social opportunities, and recruitment were least important factors. The most important factors leading to the selection of non-college alternatives were basic indecision and doubt about college attendance, and financial and practical considerations. As to continued future planning in the development of these late adolescents, it was found that approximately 70% did have definite plans for the future, whereas 30% were undecided or gave no response. Two thirds of the Ss who changed colleges chose to attend another college located within the state of Utah, with the remaining choices covering a wide geographical area. Considerable variation in the degree of rationality in these decisions was implied by the factors that did or did not influence their decisions. The model of Koontz and O\u27Donnell for rational decision making was applied, but adult models may not be appropriate for the late adolescent stage of development. The results were discussed in relation to the literature reviewed and recommendations were made for future research
Limited utility of qPCR-based detection of tumor-specific circulating mRNAs in whole blood from clear cell renal cell carcinoma patients
BACKGROUND:
RNA sequencing data is providing abundant information about the levels of dysregulation of genes in various tumors. These data, as well as data based on older microarray technologies have enabled the identification of many genes which are upregulated in clear cell renal cell carcinoma (ccRCC) compared to matched normal tissue. Here we use RNA sequencing data in order to construct a panel of highly overexpressed genes in ccRCC so as to evaluate their RNA levels in whole blood and determine any diagnostic potential of these levels for renal cell carcinoma patients.
METHODS:
A bioinformatics analysis with Python was performed using TCGA, GEO and other databases to identify genes which are upregulated in ccRCC while being absent in the blood of healthy individuals. Quantitative Real Time PCR (RT-qPCR) was subsequently used to measure the levels of candidate genes in whole blood (PAX gene) of 16 ccRCC patients versus 11 healthy individuals. PCR results were processed in qBase and GraphPadPrism and statistics was done with Mann-Whitney U test.
RESULTS:
While most analyzed genes were either undetectable or did not show any dysregulated expression, two genes, CDK18 and CCND1, were paradoxically downregulated in the blood of ccRCC patients compared to healthy controls. Furthermore, LOX showed a tendency towards upregulation in metastatic ccRCC samples compared to non-metastatic.
CONCLUSIONS:
This analysis illustrates the difficulty of detecting tumor regulated genes in blood and the possible influence of interference from expression in blood cells even for genes conditionally absent in normal blood. Testing in plasma samples indicated that tumor specific mRNAs were not detectable. While CDK18, CCND1 and LOX mRNAs might carry biomarker potential, this would require validation in an independent, larger patient cohort
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