Turbulent Jet Expansion

This report was made to study the velocity distribution in an open, in a partially open, and in a partially expanding jet. The open-jet observations reveal minor systematic discrepancies from Tollmien's theoretical velocity distribution. The shearing-stress distribution for the partially open jet was determined. The value derived for the ratio of mixing distance to jet width was found to be in close agreement with the corresponding value for the open-jet boundary. The streamline pattern in a partially expanding channel was obtained from the observed velocity distribution and plotted, after which the distribution of the mixing distance for this case was also ascertained

Reach for the stars: disentangling quantity and quality of inventors’ productivity in a multifaceted latent variable model

Star inventors generate superior innovation outcomes. Their capacity to invent high-quality patents might be decisive beyond mere productivity. However, the relationship between quantitative and qualitative dimensions has not been exhaustively investigated. The equal odds baseline (EOB) framework can explicitly model this relationship. This work com- bines a theoretical model for creative production with recent calls in the patentometrics lit- erature for multifaceted measurement of the ability to create high-quality patents. The EOB is extended and analyzed through structural equation modeling. Specifically, we compared a multifaceted EOB model with a single latent variable for quality, and a two-dimensional model that distinguishes between technological complexity and value of invention portfo- lios. The two-dimensional model had better fit but weaker factor scores (for the “value” latent variable) than the unidimensional model. These findings suggest that both the uni- and the two-dimensional approaches can be directly used for extending research on star inventors, while for practical high-stakes assessments the two-dimensional model would require further improvements

Why summing up bibliometric indicators does not justify a composite indicator

Various bibliometric indicators have been used to assess the researchers’ impact, but composites of such indicators, namely a metric that combines various individual indicators to describe a complex construct, have received a strong critique thus far. We employ concepts from psychometrics to revisit a composite proposed by Ioannidis et al. (2020) that aimed to represent researcher impact. Based on a selected sample of highly cited researchers, our proof-of-concept study presents a psychometrically principled composite formation. Specifically, by relying on the congeneric measurement model (and related models) rooted in classical test theory, we found that one of the proposed indicators clearly violated the congeneric model’s fundamental assumption of unidimensionality, and two other indicators were excluded for redundancy. The resulting composite based on only three bibliometric indicators was found to display excellent reliability. Importantly, the reliability approached that of the composite based on five indicators, and it was clearly better than the original six-indicator composite. Further, we found rather homogeneous effective weights (i.e., relative contributions of each indicator to composite variance) for simple sum scores, and these weights were close to those calculated using an algorithm for equally effective weights. While the congeneric measurement model also showed strong measurement invariance across sexes, this model’s loadings and intercepts were not measurement invariant across scientific fields and academic age groups. Notably, we found that various derived composites correlate positively with academic age, hinting at a lack of fairness of the composites

Development and application of super-resolution fluorescence microscopy

Für eine drastische Erweiterung des Anwendungsfeldes der optischen Mikroskopie sorgte die in den letzten Jahren aufgekommene sogenannte Superauflösungsmikroskopie. Das klassische Modellsystem, um das Auflösungsvermögen derartiger Techniken zu vergleichen und zu quantifizieren, stellen Komponenten des eukaryontischen Zytoskeletts dar. Auch im Rahmen dieser Arbeit wurden derartige Zellstrukturen verwendet und anhand dessen ein quantitativer Wert für die Auflösung der Blink-Mikroskopie erhalten. Das System der Wahl waren dabei Aktinfilamente in vitro, in fixierten und in lebenden Zellen. Darüberhinaus wurde auch ein deutlich systematischerer Ansatz verfolgt, indem eine Matrix aus gezielt angeordneten Farbstoffmolekülen als Vergleichssystem verwendet wurde. Dabei wurde die gezielte Platzierung sowohl virtuell in Monte-Carlo-Simulationen, als auch real mithilfe eines Rasterkraftmikroskops durchgeführt. Die Platzierung von Farbstoffmolekülen durch die Verwendung von Rasterkraftmikroskopie wies allerdings einige Nachteile auf, wie etwa eine sehr aufwändige Durchführung und das Fehlen einer Möglichkeit zur Parallelisierung. Aus diesem Grund wurde im Folgenden auf die sogenannte DNA-Origami-Technik zurück gegriffen, um gezielte Farbstoffanordnungen zu generieren. Diese dienten nun als Testprobe sowohl für die Blink-Mikroskopie, als auch für die superauflösenden Techniken PAINT und SHRImP. Schließlich wurden DNA-Origamis als generelle Auflösungsstandards für die lokalisierungsbasierte Superauflösungsmikroskopie etabliert, wobei zur automatisierten Auswertung ein spezieller Algorithmus entwickelt wurde. Die Erweiterung auf den dreidimensionalen Fall gelang durch die Nutzung von Astigmatismus-basierter 3D-Lokalisierungsmikroskopie und die Verwendung einer speziell dafür designten dreidimensionalen DNA-Origami-Struktur. Die Möglichkeit einer unkomplizierten Auswertung wurde auch in diesem Fall durch die Entwicklung eines automatisierten Detektionsalgorithmus sichergestellt.In recent years the so called super-resolution microscopy yielded to a dramatic increase of applications in optical microscopy. The common used model system to compare and quantify the resolution values of those techniques is given by components of the eukaryotic cytoskeleton. Also within this work those cell structures were used for gaining a quantitative value of the resolution of Blink Microscopy. Thereby the systems of choice were actin filaments in vitro, in stained cells and in living cells. Furthermore a much more systematic approach was carried out by using a matrix of regular arranged dye molecules as a comparison system. Thereby the accurate placement was done virtually in Monte-Carlo-simulations as well as in reality by using an atomic force microscope. However, the arrangement of fluorescent molecules by using an atomic force microscope contains a number of disadvantages, e.g. the quite high effort of the process and the lack of possibilities for parallelization. For this reason in the following the so called DNA origami technique was used for generating specific arrangements of dye molecules. These structures now functioned as calibration probe for Blink Microscopy as well as for the super-resolution techniques PAINT and SHRImP. Finally DNA origamis were established as general resolution standards for localization based super-resolution microscopy. Thereby for automated data analysis a specific algorithm was developed. The expansion to the three-dimensional case succeeded by applying astigmatism-based 3D-localization-microscopy to a specific for this case designed three-dimensional DNA-origami-structure. The option for uncomplicated data analysis was also ensured by developing of an automatic detection algorithm

Scoring divergent thinking tests: A review and systematic framework

Divergent thinking tests are often used in creativity research as measures of creative potential. However, measurement approaches across studies vary to a great extent. One facet of divergent thinking measurement that contributes strongly to differences across studies is the scoring of participants’ responses. Most commonly, responses are scored for fluency, flexibility, and originality. However, even with respect to only one dimension (e.g., originality), scoring decisions vary extensively. In the current work, a systematic framework for practical scoring decisions was developed. Scoring dimensions, instruction-scoring fit, adequacy of responses, objectivity (vs. subjectivity), level of scoring (response vs. ideational pool level), and the method of aggregation were identified as determining factors of divergent thinking test scoring. In addition, recommendations and guidelines for making these decisions and reporting the information in papers have been provided

The machines take over: a comparison of various supervised learning approaches for automated scoring of divergent thinking tasks

Traditionally, researchers employ human raters for scoring responses to creative thinking tasks. Apart from the associated costs this approach entails two potential risks. First, human raters can be subjective in their scoring behavior (inter-rater-variance). Second, individual raters are prone to inconsistent scoring patterns (intra-rater-variance). In light of these issues, we present an approach for automated scoring of Divergent Thinking (DT) Tasks. We implemented a pipeline aiming to generate accurate rating predictions for DT responses using text mining and machine learning methods. Based on two existing data sets from two different laboratories, we constructed several prediction models incorporating features representing meta information of the response or features engineered from the response’s word embeddings that were obtained using pre-trained GloVe and Word2Vec word vector spaces. Out of these features, word embeddings and features derived from them proved to be particularly effective. Overall, longer responses tended to achieve higher ratings as well as responses that were semantically distant from the stimulus object. In our comparison of three state-of-the-art machine learning algorithms, Random Forest and XGBoost tended to slightly outperform the Support Vector Regression.Correction for this article: https://doi.org/10.1002/jocb.62

Reliable individual differences in researcher performance capacity estimates: evaluating productivity as explanatory variable

Are latent variables of researcher performance capacity merely elaborate proxies of productivity? To investigate this research question, we propose extensions of recently used item-response theory models for the estimation of researcher performance capacity. We argue that productivity should be considered as a potential explanatory variable of reliable individual differences between researchers. Thus, we extend the Conway-Maxwell Poisson counts model and a negative binomial counts model by incorporating productivity as a person-covariate. We estimated six different models: a model without productivity as item and person-covariate, a model with raw productivity as person-covariate, a model with log-productivity as person covariate, a model that treats log-productivity as a known offset, a model with item-specific influences of productivity, and a model with item-specific influences of productivity as well as academic age as person-covariate. We found that the model with item-specific influences of productivity fitted two samples of social science researchers best. In the first dataset, reliable individual differences decreased substantially from excellent reliability when productivity is not modeled at all to inacceptable levels of reliability when productivity is controlled as a person-covariate, while in the second dataset reliability decreased only negligibly. This all emphasizes the critical role of productivity in researcher performance capacity estimation

Polarised Quark Distributions in the Nucleon from Semi-Inclusive Spin Asymmetries

We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range $0.003$1 GeV$^2$. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at $Q^2$=10 GeV$^2$. The polarised $u$ valence quark distribution, $\Delta u_v(x)$, is positive and the polarisation increases with $x$. The polarised $d$ valence quark distribution, $\Delta d_v(x)$, is negative and the non-strange sea distribution, $\Delta \bar q(x)$, is consistent with zero over the measured range of $x$. We find for the first moments $\int_0^1 \Delta u_v(x) dx = 0.77 \pm 0.10 \pm 0.08$, $\int_0^1 \Delta d_v(x) dx = -0.52 \pm 0.14 \pm 0.09$ and $\int_0^1 \Delta \bar q(x) dx= 0.01 \pm 0.04 \pm 0.03$, where we assumed $\Delta \bar u(x) = \Delta \bar d(x)$. We also determine for the first time the second moments of the valence distributions $\int_0^1 x \Delta q_v(x) dx$.Comment: 17 page

Paving the Way to Eureka-Introducing "Dira" as an Experimental Paradigm to Observe the Process of Creative Problem Solving

“Dira” is a novel experimental paradigm to record combinations of behavioral and metacognitive measures for the creative process. This task allows assessing chronological and chronometric aspects of the creative process directly and without a detour through creative products or proxy phenomena. In a study with 124 participants we show that (a) people spend more time attending to selected vs. rejected potential solutions, (b) there is a clear connection between behavioral patterns and self-reported measures, (c) the reported intensity of Eureka experiences is a function of interaction time with potential solutions, and (d) experiences of emerging solutions can happen immediately after engaging with a problem, before participants explore all potential solutions. The conducted study exemplifies how “Dira” can be used as an instrument to narrow down the moment when solutions emerge. We conclude that the “Dira” experiment is paving the way to study the process, as opposed to the product, of creative problem solving

Polarised quark distributions in the nucleon from semi-inclusive spin asymmetries

We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range $0.003$1~GeV$^2$. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at $Q^2$=10~GeV$^2$. The polarised $u$ valence quark distribution, $\Delta u_v(x)$, is positive and the polarisation increases with $x$. The polarised $d$ valence quark distribution, $\Delta d_v(x)$, is negative and the non-strange sea distribution, $\Delta \bar q(x)$, is consistent with zero over the measured range of $x$. We find for the first moments $\int_0^1 \Delta u_v(x) {\rm d}x = 0.77 \pm 0.10 \pm 0.08$, $\int_0^1 \Delta d_v(x) {\rm d}x = -0.52 \pm 0.14 \pm 0.09$ and $\int_0^1 \Delta \bar q(x) {\rm d}x= 0.01 \pm 0.04 \pm 0.03$, where we assumed $\Delta \bar u(x) = \Delta \bar d(x)$. We also determine for the first time the second moments of the valence distributions $\int_0^1 x \Delta q_v(x) {\rm d}x$.We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range $0.003$1 GeV$^2$. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at $Q^2$=10 GeV$^2$. The polarised $u$ valence quark distribution, $\Delta u_v(x)$, is positive and the polarisation increases with $x$. The polarised $d$ valence quark distribution, $\Delta d_v(x)$, is negative and the non-strange sea distribution, $\Delta \bar q(x)$, is consistent with zero over the measured range of $x$. We find for the first moments $\int_0^1 \Delta u_v(x) dx = 0.77 \pm 0.10 \pm 0.08$, $\int_0^1 \Delta d_v(x) dx = -0.52 \pm 0.14 \pm 0.09$ and $\int_0^1 \Delta \bar q(x) dx= 0.01 \pm 0.04 \pm 0.03$, where we assumed $\Delta \bar u(x) = \Delta \bar d(x)$. We also determine for the first time the second moments of the valence distributions $\int_0^1 x \Delta q_v(x) dx$.We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range $0.003$1 GeV$^2$. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at $Q^2$=10 GeV$^2$. The polarised $u$ valence quark distribution, $\Delta u_v(x)$, is positive and the polarisation increases with $x$. The polarised $d$ valence quark distribution, $\Delta d_v(x)$, is negative and the non-strange sea distribution, $\Delta \bar q(x)$, is consistent with zero over the measured range of $x$. We find for the first moments $\int_0^1 \Delta u_v(x) dx = 0.77 \pm 0.10 \pm 0.08$, $\int_0^1 \Delta d_v(x) dx = -0.52 \pm 0.14 \pm 0.09$ and $\int_0^1 \Delta \bar q(x) dx= 0.01 \pm 0.04 \pm 0.03$, where we assumed $\Delta \bar u(x) = \Delta \bar d(x)$. We also determine for the first time the second moments of the valence distributions $\int_0^1 x \Delta q_v(x) dx$.We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range $0.003$1 GeV$^2$. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at $Q^2$=10 GeV$^2$. The polarised $u$ valence quark distribution, $\Delta u_v(x)$, is positive and the polarisation increases with $x$. The polarised $d$ valence quark distribution, $\Delta d_v(x)$, is negative and the non-strange sea distribution, $\Delta \bar q(x)$, is consistent with zero over the measured range of $x$. We find for the first moments $\int_0^1 \Delta u_v(x) dx = 0.77 \pm 0.10 \pm 0.08$, $\int_0^1 \Delta d_v(x) dx = -0.52 \pm 0.14 \pm 0.09$ and $\int_0^1 \Delta \bar q(x) dx= 0.01 \pm 0.04 \pm 0.03$, where we assumed $\Delta \bar u(x) = \Delta \bar d(x)$. We also determine for the first time the second moments of the valence distributions $\int_0^1 x \Delta q_v(x) dx$.We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range $0.003$1 GeV$^2$. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at $Q^2$=10 GeV$^2$. The polarised $u$ valence quark distribution, $\Delta u_v(x)$, is positive and the polarisation increases with $x$. The polarised $d$ valence quark distribution, $\Delta d_v(x)$, is negative and the non-strange sea distribution, $\Delta \bar q(x)$, is consistent with zero over the measured range of $x$. We find for the first moments $\int_0^1 \Delta u_v(x) dx = 0.77 \pm 0.10 \pm 0.08$, $\int_0^1 \Delta d_v(x) dx = -0.52 \pm 0.14 \pm 0.09$ and $\int_0^1 \Delta \bar q(x) dx= 0.01 \pm 0.04 \pm 0.03$, where we assumed $\Delta \bar u(x) = \Delta \bar d(x)$. We also determine for the first time the second moments of the valence distributions $\int_0^1 x \Delta q_v(x) dx$.We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 0.0031 GeV 2 . Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at Q 2 =10 GeV 2 . The polarised u valence quark distribution, Δu v ( x ), is positive and the polarisation increases with x . The polarised d valence quark distribution, Δd v ( x ), is negative and the non-strange sea distribution, Δ q ̄ (x) , is consistent with zero over the measured range of x . We find for the first moments ∫ 0 1 Δu v (x) d x=0.77±0.10±0.08 , ∫ 0 1 Δd v (x) d x=−0.52±0.14±0.09 and ∫ 0 1 Δ q ̄ (x) d x=0.01±0.04±0.03 , where we assumed Δ u ̄ (x)=Δ d ̄ (x) . We also determine for the first time the second moments of the valence distributions ∫ 0 1 xΔq v (x) d x