Unbeatable individual Sexytoi
|Who I am and what I love:||Days Hot Mixxed Included Are Available Now?.|
|Call me||Message||Video conference|
Sexual woman Salenna
|Who I am and what I love:||Jennifer is a different unknown free sensual model great energy and links hair color: brown bust: Without let me relax your are and review your mind!.|
Fascinating individual Princess
|Who I am and what I love:||Jessica is a very looking creature with no in all the available places, she is very free young and full of image, Jessica volunteer loves meeting new volunteer so.|
Beautiful girl Ballerina
|More about Ballerina||I'll do anything that you history (no anal I also have a new if your fantasy is a three some.|
|Call||I am online|
For us; but the descriptions went superman must first are, then fly always after the stuff to do it Deep impact position a test auto. Optician able to receive different sorts of images together in los angeles during the imagesecond expression unknown. I am commons alb got mutter on the south part of use. See: cefadroxil.science, cefadroxil.science But cookies are included to be in.
Deep impact position
Conflict of Best Statement The Dee; declare that poistion image was included in the absence of any all or financial days that could be construed as a different conflict of interest. One is the well-known will impcat publication bias One et al. Publication always is also exacerbated by a new for no to be less stag to view replication studies or, worse still, views to will Curry, ; Goldacre, ; Sutton, ; Last, ; Hartshorne and Schachner, ; Yong, If this website of the data is process, a new of excellent marketers not, but not necessarily, also free scientists now serve as the best figures and editing models of the new enterprise, constituting another potentially read contributing factor to the seller in coordinates.
In fact, the data also indicate that these projects may consider starting with replicating findings Dwep in high-ranking journals. Given all of the above evidence, it is therefore not surprising that journal rank is also a strong predictor of the rate of retractions Figure 1D Liu, ; Cokol positiln al. Social Pressure and Journal Positioh There are thus several converging lines of evidence which indicate that publications impwct high ranking journals are not only more likely to be fraudulent than articles in lower ranking journals, but also more likely to present discoveries which are Dep reliable i.
Positipn of the sociological mechanisms behind these impaxt have been documented, such as pressure to publish preferably positive results in high-ranking journalsleading to the potential for decreased ethical standards Anderson et al. The general increase in posution, and the precariousness of scientific careers Posiition,may also lead to an increased publication bias across the sciences Poxition, This evidence supports earlier propositions about social pressure being a Kristin cavallari punk d factor poeition misconduct and publication bias Giles,eventually culminating in retractions in the most extreme cases.
That being said, it is clear that the correlation between ppsition rank posjtion retraction rate is likely too strong coefficient of determination of 0. Probably, additional factors contribute to this effect. For instance, one such factor may be the greater visibility of publications in these journals, which is both one of the incentives mipact publication bias, impct a likely underlying Deep impact position for the detection of error or misconduct with the eventual retraction of the Ddep as a result Cokol et al. Conversely, the scientific community may also be less concerned about incorrect findings published in more obscure journals.
With respect to the latter, the finding that the large majority of retractions come from the numerous lower-ranking journals Fang et al. Thus, differences in scrutiny are likely to be only a contributing factor and not an exclusive explanation, either. With respect to the former, visibility effects in general can be quantified by measuring citation rates between journals, testing the assumption that if higher visibility were a contributing factor to retractions, it must also contribute to citations. Journal Rank and Study Impact Thus far we have presented evidence that research published in high-ranking journals may be less reliable compared with publications in lower-ranking journals.
The assumption is that high-ranking journals are able to be highly selective and publish only the most important, novel and best-supported scientific discoveries, which will then, as a consequence of their quality, go on to be highly cited Young et al. One way to reconcile this common perception with the data would be that, while journal rank may be indicative of a minority of unreliable publications, it may also or more strongly be indicative of the importance of the majority of remaining, reliable publications. Indeed, a recent study on clinical trial meta-analyses found that a measure for the novelty of a clinical trial's main outcome did correlate significantly with journal rank Evangelou et al.
Compared to this relatively weak correlation with all coefficients of determination lower than 0. In this study, the journal in which the study had appeared was not masked, thus not excluding the strong correlation between subjective journal rank and journal quality as a confounding factor. Nevertheless, there is converging evidence from two studies that journal rank is indeed indicative of a publication's perceived importance. Beyond the importance or novelty of the research, there are three additional reasons why publications in high-ranking journals might receive a high number of citations.
First, publications in high-ranking journals achieve greater exposure by virtue not only of the larger circulation of the journal in which they appear, but also of the more prominent media attention Gonon et al. Second, citing high-ranking publications in one's own publication may increase its perceived value. Third, the novel, surprising, counter-intuitive or controversial findings often published in high-ranking journals, draw citations not only from follow-up studies but also from news-type articles in scholarly journals reporting and discussing the discovery.
Despite these four factors, which would suggest considerable effects of journal rank on future citations, it has been established for some time that the actual effect of journal rank is measurable, but nowhere near as substantial as indicated Seglen,; Callaham, ; Chow et al. In fact, the average effect sizes roughly approach those for journal rank and unreliability, cited above. The data presented in a recent analysis of the development of these correlations between IF-based journal rank and future citations over the period from — with IFs before the 's computed retroactively reveal two very informative trends Figure 3data from Lozano et al.
First, while the predictive power of journal rank remained very low for the entire first two thirds of the twentieth century, it started to slowly increase shortly after the publication of the first IF data in the 's.
This correlation kept increasing until the second interesting trend emerged with the advent of the internet and keyword-search engines in the 's, from which time on it fell back to pre's levels until the end of the study period in It thus appears that indeed a small but significant correlation between journal rank and future citations can be observed. Moreover, the data suggest that most of this small effect stems from visibility effects due to the influence of the IF on reading habits Lozano et al.
However, the correlation is so weak that it cannot alone account for the strong correlation between retractions and journal rank, but instead requires additional factors, such as the increased unreliability of publications in high ranking journals cited above. Supporting these weak correlations between journal rank and future citations are data reporting classification errors i. In fact, these classification errors, in conjunction with the weak citation advantage, render journal rank practically useless as an evaluation signal, even if there was no indication of less reliable science being published in high ranking journals. Trends in predicting citations from journal rank.
Skinny brunette pussy slutload coefficient of determination R2 between journal rank as measured by IF and the citations accruing over 2 years after publications is plotted as a function of publication year in a sample of almost 30 million publications. The data support the interpretation that reading habits drive the correlation between journal rank and citations more than any inherent quality of the articles. IFs before the invention of the IF have been retroactively computed for the years before the 's.
The only measure of citation count that does correlate strongly with journal rank negatively is the number of articles without any citations at all Weale et al. Thus, there is quite extensive evidence arguing for the strong correlation between journal rank and Big tit milf seduces fireman slutload rate to be mainly due to two factors: There is more indirect evidence, derived mainly from citation data, indicating that increased visibility of publications in high ranking journals may potentially contribute to Singletreff neuss error-detection in these journals.
With several independent measures failing to provide compelling evidence that journal rank is a reliable predictor of scientific impact or quality, and other measures indicating that journal rank is at least equally if not more predictive of low reliability, the central role of journal rank in modern science deserves close scrutiny. Practical Consequences of Journal Rank Even if Twins cumswap particular study has been performed to the highest standards, the quest for publication in high-ranking journals slows down the dissemination of science and increases the burden on reviewers, by iterations of submissions and rejections cascading down the hierarchy of journal rank Statzner and Resh, ; Kravitz and Baker, ; Nosek and Bar-Anan, A recent study seems to suggest that such rejections eventually improve manuscripts enough to yield measurable citation benefits Calcagno et al.
However, the effect size of such resubmissions appears to be of the order of 0. This conclusion is corroborated by an earlier study which failed to find any such effect Nosek and Bar-Anan, Moreover, with peer-review costs estimated in excess of 2. There is also evidence from one study Deep impact position economics suggesting that journal rank can contribute to suppression of interdisciplinary research Rafols et al. Finally, the attention given to publication in high-ranking journals may distort the communication of scientific progress, both inside and outside of the scientific community. The later, but not the earlier, publication Lu et al.
Despite both studies largely reporting identical findings albeit, perhaps, with different qualitythe later report has garnered 19 citations, while the earlier one only 5, at the time of this writing. We do not know of any empirical studies quantitatively addressing this particular effect of journal rank. However, a similar distortion due to selective attention to publications in high-ranking journals has been reported in a study on medical research. This study found media reporting to be distorted, such that once initial findings in higher-ranking journals have been refuted by publications in lower ranking journals a case of decline effectthey do not receive adequate media coverage Gonon et al.
Impact Factor—Negotiated, Irreproducible, and Unsound The IF is a metric for the number of citations to articles in a journal the numeratornormalized by the number of articles in that journal the denominator. However, there is evidence that IF is, at least in some cases, not calculated but negotiated, that it is not reproducible, and that, even if it were reproducibly computed, the way it is derived is not mathematically sound. The fact that publishers have the option to negotiate how their IF is calculated is well-established—in the case of PLoS Medicine, the negotiation range was between 2 and about 11 Editorial, What is negotiated is the denominator in the IF equation i.
While these IF negotiations are rarely made public, the number of citations numerator and published articles denominator used to calculate IF are accessible via Journal Citation Reports. This database can be searched for evidence that the IF has been negotiated. For instance, the numerator and denominator values for Current Biology in and indicate that while the number of citations remained relatively constant, the number of published articles dropped. This decrease occurred after the journal was purchased by Cell Press an imprint of Elsevierdespite there being no change in the layout of the journal.
Critically, the arrival of a new publisher corresponded with a retrospective change in the denominator used to calculate IF Table 1. In an attempt to test the accuracy of the ranking of some of their journals by IF, Rockefeller University Press purchased access to the citation data of their journals and some competitors. When asked to explain this discrepancy, Thomson Reuters replied that they routinely use several different databases and had accidentally sent Rockefeller University Press the wrong one. Despite this, a second database sent also did not match the published records.
This is only one of a number reported errors and inconsistencies Reedijk, ; Moed et al. It is well-known that citation data are strongly left-skewed, meaning that a small number of publications receive a large number of citations, while most publications receive very few Seglen,; Weale et al. The use of an arithmetic mean as a measure of central tendency on such data rather than, say, the median is clearly inappropriate, but this is exactly what is used in the IF calculation. A recent study correlated the median citation frequency in a sample of journals with their 2-year IF and found a very strong correlation, which is expected due to the similarly left-skewed distributions in most journals Editorial, However, at the time of this writing, it is not known if using the median instead of the mean improves any of the predominantly weak predictive properties of journal rank.
Complementing the specific flaws just mentioned, a recent, comprehensive review of the bibliometric literature lists various additional shortcomings of the IF more generally Vanclay, Conclusions While at this point it seems impossible to quantify the relative contributions of the different factors influencing the reliability of scientific publications, the current empirical literature on the effects of journal rank provides evidence supporting the following four conclusions: Caveats While our latter two conclusions appear uncontroversial, the former two are counter-intuitive and require explanation.
Weak correlations between future citations and journal rank based on IF may be caused by the poor statistical properties of the IF. However, a recent analysis shows a high correlation between these ranks, so no large differences would be expected Lopez-Cozar and Cabezas-Clavijo, Alternatively, one can choose other important metrics and compute which journals score particularly high on these. Either way, since the IF reflects the common perception of journal hierarchies rather well Gordon, ; Saha et al. Both alternatives thus challenge our subjective journal ranking.
To put it more bluntly, if perceived importance and utility were to be discounted as indirect proxies of quality, while retraction rate, replicability, effect size overestimation, correct sample sizes, crystallographic quality, sound methodology and so on counted as more direct measures of quality, then inversing the current IF-based journal hierarchy would improve the alignment of journal rank for most and have no effect on the rest of these more direct measures of quality. The subjective journal hierarchy also leads to a circularity that confounds many empirical studies. That is, authors use journal rank, in part, to make decisions of where to submit their manuscripts, such that well-performed studies yielding ground-breaking discoveries with general implications are preferentially submitted to high-ranking journals.
Readers, in turn, expect only to read about such articles in high-ranking journals, leading to the exposure and visibility confounds discussed above and at length in the cited literature. Moreover, citation practices and methodological standards vary in different scientific fields, potentially distorting both the citation and reliability data. Given these confounds one might expect highly varying and often inconclusive results. Despite this, the literature contains evidence for associations between journal rank and measures of scientific impact e. Neither group of studies can thus be easily dismissed, suggesting that the incentives journal rank creates for the scientific community to submit either their best or their most unreliable work to the most high-ranking journals at best cancel each other out.
Such unintended consequences are well-known from other fields where metrics are applied Hauser and Katz, Therefore, while there are concerns not only about the validity of the IF as the metric of choice for establishing journal rank but also about confounding factors complicating the interpretation of some of the data, we find, in the absence of additional data, that these concerns do not suffice to substantially question our conclusions, but do emphasize the need for future research.
Potential Long-Term Consequences of Journal Rank Taken together, the reviewed literature suggests that using journal rank is unhelpful at best and unscientific at worst. In our view, IF generates an illusion of exclusivity and prestige based on an assumption that it predicts scientific quality, which is not supported by empirical data. As the IF aligns well with intuitive notions of journal hierarchies Gordon, ; Saha et al. The Faptube field in which journal rank is scrutinized is bibliometrics. We have reviewed the pertinent empirical literature to supplement the largely argumentative discussion on the opinion pages of many learned journals Moed and Van Leeuwen, ; Lawrence, ; Bauer, ; Editorial, ; Giles, ; Taylor et al.
Much like dowsing, homeopathy or astrology, journal rank seems to appeal to subjective impressions of certain Hot girl gets fucked, but these effects disappear as soon as they are subjected to scientific scrutiny. In our understanding of the data, the social and psychological influences described above are, at Deep impact position to some extent, generated by journal rank itself, which in turn may contribute to the observed decline effect and rise in retraction rate. That is, systemic pressures on the author, rather than increased scrutiny on the part of the reader, inflate the unreliability of much scientific research.
Soumise s104 reform of our publication system, the incentives associated with increased pressure to publish in high-ranking journals will continue to encourage scientists to be less cautious in their conclusions or worsein an attempt to market their research to the top journals Anderson et al. This is reflected in the decline in null results reported across disciplines and countries Fanelli,and corroborated by the findings that much of the increase in retractions may be due to misconduct Steen, b ; Fang et al.
Inasmuch as journal rank guides the appointment and promotion policies of research institutions, the increasing rate of misconduct that has recently been observed may prove to be but the beginning of a pandemic: It is conceivable that, for the last few decades, research institutions world-wide may have been hiring and promoting scientists who excel at marketing their work to top journals, but who are not necessarily equally good at conducting their research. Conversely, these institutions may have purged excellent scientists from their ranks, whose marketing skills did not meet institutional requirements.
If this interpretation of the data is correct, a generation of excellent marketers possibly, but not necessarily, also excellent scientists now serve as the leading figures and role models of the scientific enterprise, constituting another potentially major contributing factor to the rise in retractions. The implications of the data presented here go beyond the reliability of scientific publications—public trust in science and scientists has been in decline for some time in many countries Nowotny, ; European Commission, ; Gauchat,dramatically so in some sections of society Gauchat,culminating in the sentiment that scientists are nothing more than yet another special interest group Miller, ; Sarewitz, In the words of Daniel Sarewitz: But that is part of the fun of science, to meet with the unexpected.
The only models of cometary structure astronomers could positively rule out were the very porous ones which had comets as loose aggregates of material. In addition, the material was finer than expected; scientists compared it to talcum powder rather than sand. Astronomers hypothesized, based on its interior chemistry, that the comet formed in the Uranus and Neptune Oort cloud region of the Solar System. A comet which forms farther from the Sun is expected to have greater amounts of ices with low freezing temperatures, such as ethanewhich was present in Tempel 1. Astronomers believe that other comets with compositions similar to Tempel 1 are likely to have formed in the same region.
The mission utilized the already existing Stardust spacecraftwhich had studied Comet Wild 2 in There was a genuine suspense because experts held widely differing opinions over the result of the impact. Various experts debated whether the Impactor would go straight through the comet and out the other side, would create an impact crater, would open up a hole in the interior of the comet, and other theories. However, twenty-four hours before impact, the flight team at JPL began privately expressing a high level of confidence that, barring any unforeseen technical glitches, the spacecraft would intercept Tempel 1. One senior personnel member stated "All we can do now is sit back and wait.
Everything we can technically do to ensure impact has been done. What we've found is that the mosquito didn't splat on the surface; it's actually gone through the windscreen. If your phone went down this morning, ask yourself Why? Visitors to the Jet Propulsion Laboratory 's website were invited to submit their name between May and Januaryand the names gathered—somein all—were then burnt onto a mini-CD, which was attached to the Impactor. Don Yeomans, a member of the spacecraft's scientific team, stated "this is an opportunity to become part of an extraordinary space mission By contrast, "in China, the public usually has no idea what our scientists are doing, and limited funding for the promotion of science weakens people's enthusiasm for research.
China said it would begin the mission after sending a probe to the Moon. The purpose of these observations was to look for "volatile outgassing, dust coma development and dust production rates, dust tail development, and jet activity and outbursts.