3,367,838 research outputs found
Data analysis and graphing in an introductory physics laboratory: spreadsheet versus statistics suite
Two methods of data analysis are compared: spreadsheet software and a
statistics software suite. Their use is compared analyzing data collected in
three selected experiments taken from an introductory physics laboratory, which
include a linear dependence, a non-linear dependence, and a histogram. The
merits of each method are compared.Comment: 13 pages, 7 figures, accepted for publication in the European Journal
of Physics; a spreadsheet is included as a supplement in the aux subdirector
Preparing Laboratory and Real-World EEG Data for Large-Scale Analysis: A Containerized Approach.
Large-scale analysis of EEG and other physiological measures promises new insights into brain processes and more accurate and robust brain-computer interface models. However, the absence of standardized vocabularies for annotating events in a machine understandable manner, the welter of collection-specific data organizations, the difficulty in moving data across processing platforms, and the unavailability of agreed-upon standards for preprocessing have prevented large-scale analyses of EEG. Here we describe a "containerized" approach and freely available tools we have developed to facilitate the process of annotating, packaging, and preprocessing EEG data collections to enable data sharing, archiving, large-scale machine learning/data mining and (meta-)analysis. The EEG Study Schema (ESS) comprises three data "Levels," each with its own XML-document schema and file/folder convention, plus a standardized (PREP) pipeline to move raw (Data Level 1) data to a basic preprocessed state (Data Level 2) suitable for application of a large class of EEG analysis methods. Researchers can ship a study as a single unit and operate on its data using a standardized interface. ESS does not require a central database and provides all the metadata data necessary to execute a wide variety of EEG processing pipelines. The primary focus of ESS is automated in-depth analysis and meta-analysis EEG studies. However, ESS can also encapsulate meta-information for the other modalities such as eye tracking, that are increasingly used in both laboratory and real-world neuroimaging. ESS schema and tools are freely available at www.eegstudy.org and a central catalog of over 850 GB of existing data in ESS format is available at studycatalog.org. These tools and resources are part of a larger effort to enable data sharing at sufficient scale for researchers to engage in truly large-scale EEG analysis and data mining (BigEEG.org)
Data analysis of Einstein-Podolsky-Rosen-Bohm laboratory experiments
Data sets produced by three different Einstein-Podolsky-Rosen-Bohm (EPRB)
experiments are tested against the hypothesis that the statistics of this data
is described by quantum theory. Although these experiments generate data that
violate Bell inequalities for suitable choices of the time-coincidence window,
the analysis shows that it is highly unlikely that these data sets are
compatible with the quantum theoretical description of the EPRB experiment,
suggesting that the popular statements that EPRB experiments agree with quantum
theory lack a solid scientific basis and that more precise experiments are
called for.Comment: arXiv admin note: substantial text overlap with arXiv:1112.262
Staphylococcus aureus in the oral cavity: a three-year retrospective analysis of clinical laboratory data
OBJECTIVE: A retrospective analysis of laboratory data to investigate the isolation of Staphylococcus aureus from the oral cavity and facial area in specimens submitted to a regional diagnostic oral microbiology laboratory. METHODS: A hand search of laboratory records for a three-year period (1998-2000) was performed for specimens submitted to the regional diagnostic oral microbiology laboratory based at Glasgow Dental Hospital and School. Data were collected from forms where S. aureus was isolated. These data included demographics, referral source, specimen type, methicillin susceptibility and clinical details. RESULTS: For the period 1998-2000, there were 5,005 specimens submitted to the laboratory. S. aureus was isolated from 1,017 specimens, of which 967 (95%) were sensitive to methicillin (MSSA) and 50 (5%) were resistant to methicillin (MRSA). The 1,017 specimens were provided from 615 patients. MRSA was isolated from 37 (6%) of patients. There was an increasing incidence of S. aureus with age, particularly in the greater than 70 years age group. The most common specimen from which MSSA was isolated was an oral rinse (38%) whilst for MRSA isolates this was a tongue swab (28%). The clinical condition most commonly reported for MSSA isolates was angular cheilitis (22%). Erythema, swelling, pain or burning of the oral mucosa was the clinical condition most commonly reported for MRSA isolates (16%). Patients from whom the MSSA isolates were recovered were most commonly (55%) seen in the oral medicine clinic at the dental hospital, whilst patients with MRSA were more commonly seen in primary care settings such as nursing homes, hospices and general dental practice (51%). CONCLUSION: In line with more recent surveys, this retrospective study suggests that S. aureus may be a more frequent isolate from the oral cavity than hitherto suspected. A small proportion of the S. aureus isolates were MRSA. There were insufficient data available to determine whether the S. aureus isolates were colonising or infecting the oral cavity. However, the role of S. aureus in several diseases of the oral mucosa merits further investigation
Optimized R functions for analysis of ecological community data using the R virtual laboratory (RvLab)
Background:
Parallel data manipulation using R has previously been addressed by members of the R community, however most of these studies produce ad hoc solutions that are not readily available to the average R user. Our targeted users, ranging from the expert ecologist/microbiologists to computational biologists, often experience difficulties in finding optimal ways to exploit the full capacity of their computational resources. In addition, improving performance of commonly used R scripts becomes increasingly difficult especially with large datasets. Furthermore, the implementations described here can be of significant interest to expert bioinformaticians or R developers. Therefore, our goals can be summarized as: (i) description of a complete methodology for the analysis of large datasets by combining capabilities of diverse R packages, (ii) presentation of their application through a virtual R laboratory (RvLab) that makes execution of complex functions and visualization of results easy and readily available to the end-user.
New information:
In this paper, the novelty stems from implementations of parallel methodologies which rely on the processing of data on different levels of abstraction and the availability of these processes through an integrated portal. Parallel implementation R packages, such as the pbdMPI (Programming with Big Data – Interface to MPI) package, are used to implement Single Program Multiple Data (SPMD) parallelization on primitive mathematical operations, allowing for interplay with functions of the vegan package. The dplyr and RPostgreSQL R packages are further integrated offering connections to dataframe like objects (databases) as secondary storage solutions whenever memory demands exceed available RAM resources.
The RvLab is running on a PC cluster, using version 3.1.2 (2014-10-31) on a x86_64-pc-linux-gnu (64-bit) platform, and offers an intuitive virtual environmet interface enabling users to perform analysis of ecological and microbial communities based on optimized vegan functions.
A beta version of the RvLab is available after registration at: https://portal.lifewatchgreece.eu
Dynamic mechanical analysis and organization/storage of data for polymetric materials
Dynamic mechanical analysis was performed on a variety of temperature resistant polymers and composite resin matrices. Data on glass transition temperatures and degree of cure attained were derived. In addition a laboratory based computer system was installed and data base set up to allow entry of composite data. The laboratory CPU termed TYCHO is based on a DEC PDP 11/44 CPU with a Datatrieve relational data base. The function of TYCHO is integration of chemical laboratory analytical instrumentation and storage of chemical structures for modeling of new polymeric structures and compound
Precision laboratory UV and IR wavelengths for cosmological and astrophysical applications
The quality of astronomical spectra is now so high that the accuracy of the
laboratory data is getting more and more important for the analysis and
interpretation. Both in astrophysics and cosmology the needs for accurate
laboratory wavelengths have increased with the development of new ground-based
and air-borne telescopes and spectrographs. The high resolution UV Fourier
Transform spectrometer at Lund Observatory is being used for studying
laboratory spectra of astrophysically important elements. Measurements of
accurate laboratory UV and IR wavelengths have been made for cosmological and
astrophysical applications.Comment: To appear in the proceedings of "Precision Spectroscopy in
Astrophysics", Aveiro, Portugal, Sep. 2006, eds Pasquini et al., ESO
Astrophysics Symposia. 2 pages, 2 figure
Investigation of low energy space plasma
Analysis techniques and software development, data analysis and modeling, laboratory plasma flow studies, meetings, and publications are presented
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