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Null Result
In science, a null result is a result without the expected content: that is, the proposed result is absent. It is an experimental outcome which does not show an otherwise expected effect. This does not imply a result of zero or nothing, simply a result that does not support the hypothesis. In statistical hypothesis testing, a null result occurs when an experimental result is not significantly different from what is to be expected under the null hypothesis; its probability (under the null hypothesis) does not exceed the significance level, i.e., the threshold set prior to testing for rejection of the null hypothesis. The significance level varies, but common choices include 0.10, 0.05, and 0.01. However, a non-significant result does not necessarily mean that an effect is absent. As an example in physics, the results of the Michelson–Morley experiment were of this type, as it did not detect the expected velocity relative to the postulated luminiferous aether. This experiment's fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science
Science is a systematic discipline that builds and organises knowledge in the form of testable hypotheses and predictions about the universe. Modern science is typically divided into twoor threemajor branches: the natural sciences, which study the physical world, and the social sciences, which study individuals and societies. While referred to as the formal sciences, the study of logic, mathematics, and theoretical computer science are typically regarded as separate because they rely on deductive reasoning instead of the scientific method as their main methodology. Meanwhile, applied sciences are disciplines that use scientific knowledge for practical purposes, such as engineering and medicine. The history of science spans the majority of the historical record, with the earliest identifiable predecessors to modern science dating to the Bronze Age in Ancient Egypt, Egypt and Mesopotamia (). Their contributions to mathematics, astronomy, and medicine entered and shaped the Gree ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Controlled Clinical Trials
''Contemporary Clinical Trials'' is a monthly peer-reviewed medical journal covering clinical trials and research design in clinical medicine. It was established in 2005 and is published by Elsevier. The editor-in-chief is JoAnn E. Manson. it was established in 1980 as ''Controlled Clinical Trials'' and obtained its current title in 2005. According to the ''Journal Citation Reports'', the journal has a 2020 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a type of journal ranking. Journals with higher impact factor values are considered more prestigious or important within their field. The Impact Factor of a journa ... of 2.226. References External links * {{Official website, https://www.sciencedirect.com/journal/contemporary-clinical-trials General medical journals Elsevier academic journals English-language journals Bimonthly journals Academic journals established in 1980 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noise (electronics)
In electronics, noise is an unwanted disturbance in an electrical signal. Noise generated by electronic devices varies greatly as it is produced by several different effects. In particular, noise is inherent in physics and central to thermodynamics. Any conductor with electrical resistance will generate thermal noise inherently. The final elimination of thermal noise in electronics can only be achieved cryogenically, and even then quantum noise would remain inherent. Electronic noise is a common component of noise in signal processing. In communication systems, noise is an error or undesired random disturbance of a useful information signal in a communication channel. The noise is a summation of unwanted or disturbing energy from natural and sometimes man-made sources. Noise is, however, typically distinguished from interference, for example in the signal-to-noise ratio (SNR), signal-to-interference ratio (SIR) and signal-to-noise plus interference ratio (SNIR) measu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imponderable Fluid
Imponderable fluids are features of several superseded scientific theories, such as archaic atomic and electromotive theories. Traces of these hypothetical fluids survive in phrases like energy storage, etc. Description The term has been used in natural philosophy and physics to explain certain phenomena as the result of invisible and practically weightless (Latin: ''imponderabilis'') fluids. Historically proposed imponderable fluids include phlogiston and caloric; additionally some physicists considered electricity imponderable. Fluids theories In an article published in 1868, English inventor and polymath Fleeming Jenkin described myriad hypotheses of physics that had been put forth involving imponderable fluids: Leibniz mentions with great disapproval a certain Hartsoeker who supposed that atoms moved in an ambient fluid, though the idea is not unlike his own. It is difficult to trace the origin of the hypothesis, but Galileo and Hobbes both speak of a subtle ether. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aether Theories
In the history of physics, aether theories (or ether theories) proposed the existence of a medium, a space-filling substance or field as a transmission medium for the propagation of electromagnetic or gravitational forces. Since the development of special relativity, theories using a substantial aether fell out of use in modern physics, and are now replaced by more abstract models. This early modern aether has little in common with the aether of classical elements from which the name was borrowed. The assorted theories embody the various conceptions of this medium and substance. Historical models Luminiferous aether Isaac Newton suggests the existence of an aether in the Third Book of ''Opticks'' (1st ed. 1704; 2nd ed. 1718): "Doth not this aethereal medium in passing out of water, glass, crystal, and other compact and dense bodies in empty spaces, grow denser and denser by degrees, and by that means refract the rays of light not in a point, but by bending them gradually in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BioMed Central
BioMed Central (BMC) is a United Kingdom-based, for-profit scientific open access publisher that produces over 250 scientific journals. All its journals are published online only. BioMed Central describes itself as the first and largest open access science publisher. It was founded in 2000 and has been owned by Springer, now Springer Nature, since 2008. History BioMed Central was founded in 2000 as part of the Current Science Group (now Science Navigation Group, SNG), a nursery of scientific publishing companies. SNG chairman Vitek Tracz developed the concept for the company after NIH director Harold Varmus's PubMed Central concept for open-access publishing was scaled back. The first director of the company was Jan Velterop. Chemistry Central was established in 2006 and the PhysMath Central journal imprint in 2007. In 2002, the company introduced article processing charges, and these have since been the primary source of revenue. In 2007, Yale University Libraries s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Unsolved Questions
The ''Journal of Unsolved Questions'' or ''JUnQ'' is an open access peer-reviewed scientific journal which publishes null results. Based in Mainz, Germany, it features articles from multiple disciplines. History Negative or null results are often not published by scientific journals, leading to other scientists unnecessarily repeating their colleagues' work. In order to make previous null results publicly available, scientists at the Johannes Gutenberg University Mainz The Johannes Gutenberg University Mainz () is a public research university in Mainz, Rhineland Palatinate, Germany. It has been named after the printer Johannes Gutenberg since 1946. it had approximately 32,000 students enrolled in around 100 a ... established the ''Journal of Unsolved Questions'' in 2011. References Further reading * * External links * 2011 establishments in Germany English-language journals Multidisciplinary scientific journals Academic journals established in 2011 Biannual j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Pharmaceutical Negative Results ...
External linksList of journals on Medknow Publications website * Medknow Publications Medknow Publications also known as Wolters Kluwer Medknow or simply Medknow, is a publisher of academic journals on behalf of learned societies and associations. Previously an independent Indian publisher, Medknow is now part of within Wolters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Negative Results In Biomedicine
The ''Journal of Negative Results in Biomedicine'' was a peer-reviewed open access medical journal. It published papers that promote a discussion of unexpected, controversial, provocative and/or negative results in the context of current research. The journal was established in 2002 and ceased publishing in September 2017. It was abstracted and indexed in the Emerging Sources Citation Index, Index Medicus/MEDLINE/PubMed, and Scopus Scopus is a scientific abstract and citation database, launched by the academic publisher Elsevier as a competitor to older Web of Science in 2004. The ensuing competition between the two databases has been characterized as "intense" and is c .... References External links * English-language journals Academic journals established in 2002 Publications disestablished in 2017 General medical journals BioMed Central academic journals Creative Commons Attribution-licensed journals {{general-medical-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-response Bias
Participation bias or non-response bias is a phenomenon in which the results of studies, polls, etc. become non-representative because the participants disproportionately possess certain traits which affect the outcome. These traits mean the sample is systematically different from the target population, potentially resulting in biased estimates. For instance, a study found that those who refused to answer a survey on AIDS tended to be "older, attend church more often, are less likely to believe in the confidentiality of surveys, and have lower sexual self disclosure." It may occur due to several factors as outlined in Deming (1990). Non-response bias can be a problem in longitudinal research due to attrition during the study. Example If one selects a sample of 1000 managers in a field and polls them about their workload, the managers with a high workload may not answer the survey because they do not have enough time to answer it, and/or those with a low workload may decline ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Dredging
Data dredging, also known as data snooping or ''p''-hacking is the misuse of data analysis to find patterns in data that can be presented as statistically significant, thus dramatically increasing and understating the risk of false positives. This is done by performing many statistical tests on the data and only reporting those that come back with significant results. Thus data dredging is also often a misused or misapplied form of data mining. The process of data dredging involves testing multiple hypotheses using a single data set by exhaustively searching—perhaps for combinations of variables that might show a correlation, and perhaps for groups of cases or observations that show differences in their mean or in their breakdown by some other variable. Conventional tests of statistical significance are based on the probability that a particular result would arise if chance alone were at work, and necessarily accept some risk of mistaken conclusions of a certain type (mistak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lancet (journal)
''The Lancet'' is a weekly peer-reviewed general medical journal, founded in England in 1823. It is one of the world's highest-impact academic journals and also one of the oldest medical journals still in publication. The journal publishes original research articles, review articles ("seminars" and "reviews"), editorials, book reviews, correspondence, as well as news features and case reports. ''The Lancet'' has been owned by Elsevier since 1991, and its editor-in-chief since 1995 has been Richard Horton. The journal has editorial offices in London, New York City, and Beijing. History ''The Lancet'' was founded in 1823 by Thomas Wakley, an English surgeon who named it after the surgical instrument called a lancet (scalpel). According to BBC, the journal was initially considered to be radical following its founding. Members of the Wakley family retained editorship of the journal until 1908. In 1921, ''The Lancet'' was acquired by Hodder & Stoughton. Elsevier acquired ''T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
