196,217 research outputs found
"Variation of outdoor illumination as a function of solar elevation and light pollution" (Spitschan et al.) – Raw Data
Full text link"Variation of outdoor illumination as a function of solar elevation and light pollution" (Spitschan et al.) – Raw DataThis is the raw data collected for the data base of outdoor illumination spectra described by Spitschan, Aguirre, Brainard & Sweeney (2016). The spectra provided here are raw, uncalibrated and unprocessed.Code to process these data is provided at https://github.com/spitschan/IlluminationSpectraDataset.
MD5 (calibrationdata.tar.gz) = 92102c29bbc54f3d426d2d17f67ad526MD5 (dataraw.tar.gz) = 351c6d0c5dd44e748af483d035954504</p
Wie wirkt Licht auf uns Menschen?
No full textSind manche Menschen abends leistungsfähiger als morgens, oder ist das nur Disziplin? Gibt es wirklich eine innere Uhr und wenn ja, wie funktioniert sie? In dieser Podcast-Folge gehen wir der Wirkung des Lichts auf den Organismus auf den Grund. Dazu sprechen wir mit Prof. Dr. Manuel Spitschan vom Max-Planck-Institut für biologische Kybernetik
Illuminate your clock: How light exposure impacts your health and well-being
No full textHuman physiology and behaviour are organised at the 24-hour scale through our biological clock. Light exposure influences this clock through a pathway connecting our eyes to the central circadian pacemaker. Light at the wrong time can negatively impact our circadian rhythms and sleep, but light exposure can also have a strong positive influence by making us more alert. In this talk, Manuel Spitschan will discuss recent findings on how interdisciplinary research can help us use light optimally
Find the switch for healthy artificial lighting
Full text linkIn my view, developments in lighting technology call for a deeper insight than we have at present into how artificial light affects our physiology and behaviour (see K. M. Zielinska-Dabkowska Nature 553, 274–276; 2018). At the right (or wrong) time, light can suppress the production of melatonin, advance or delay our internal clock, and affect how alert we are. These visual functions depend on a special class of cell in the human eye that responds to light signals independently of the rods and cones used for image perception. Known as intrinsically photosensitive retinal ganglion cells, they express a pigment called melanopsin that is sensitive to short-wavelength light. The boost in the contribution of short-wavelength illumination at dawn and dusk relative to daylight seems to act as a crucial signal for circadian rhythms (M. Spitschan et al. Sci. Rep. 6, 26756; 2016). It stimulates activity in mice during those times (L. Walmsley et al. PLoS Biol. 13, e1002127; 2015). These and other facets of the complex circadian system need to be investigated if we are to design genuinely healthy artificial lighting
Wearable Light Loggers: From Optical Radiation to Health-Related Metrics
No full textThe past decades have generated compelling laboratory evidence showing that light exposure profoundly impacts on human circadian physiology through a pathway connecting a subset of ganglion cells in the retina to the hypothalamus. While these laboratory studies generally demonstrate the biological capacity of non-visual photoreceptive pathways to respond to light, the significance and relevance of light exposure in the real world does not immediately follow from "biological capacity" studies. One key component for understanding the impact of light exposure in the real world is measuring patterns of light exposure. In the past years, wearable light loggers have become available to accomplish this task. In this webinar hosted by the Color Technical Group, Manuel Spitschan will review new developments in this area and discuss challenges and research gaps that need to be addressed
"Human visual cortex responses to rapid cone and melanopsin-directed flicker" (Spitschan et al.) – Data Supplement
No full text<p><strong>"Human visual cortex responses to rapid cone and melanopsin-directed flicker" (Spitschan <i>et al.</i>)</strong></p>
<p><b>Data Supplement</b></p><p><br></p><p><b>Figures</b> </p>
<p><strong>Figure S1 [Figure_S1.pdf] | Echoplanar image intensity</strong>. Representative echoplanar images for each subject. The three views (sagittal, horizontal, and coronal) also include a colored overlay of the visual area ROIs (V1 and V2/V3, not restricted in eccentricity range). Image intensity is the mean of the set of spatially-aligned echoplanar images from a single scanning run and reflects signal-to-noise for a given spatial location. ROIs defined on the cortical surface were projected back to the volumetric space using FreeSurfer.</p>
<p><strong>Figure S2 [Figure_S2.pdf] | Psychophysical nulling (average)</strong>. <em>a</em>, Perceptual nulling data for a 32% melanopsin (Mel*; non penumbral-cone silent) modulation in a population of subjects (n=15). Primary subjects (S01, S02, and S03) indicated with a star symbol. Ellipse indicates ±1SD across subjects. Some plot points are overlapping. <em>b</em>, Perceptual nulling data for a 32% cone directed (L+M+S) modulation in the same population of 15 subjects. Red error bar indicates ±1SD across subjects. Averages were obtained from the positive and negative arms shown in Fig. 3. All data are tabulated in Table S6.</p>
<p><strong>Figure S3 [Figure_S3.pdf] | V2/V3, MT and LOC response to melanopsin modulations.</strong> BOLD amplitudes shown as average across the two ROI hemispheres and across ROI vertices in the relevant eccentricity range (inset). Format follows Fig. 5.</p>
<p><strong>Figure S4 [Figure_S4.pdf] | Additional BOLD data.</strong> BOLD amplitudes shown as average across the two V1 hemispheres and across V1 vertices in the relevant eccentricity range (3°-13°). Subjects viewed 12 sec 4 Hz flicker with a dilated pupil. Experimental details and data analysis follows main experiments. Melanopsin and L+M+S modulations were nulled prior to the experiment. All modulations at ±32% contrast. Data shown were not included in the main report because of 1) equipment failure, preventing us from collecting behavioral responses during the attention task, 2) concern that subject S03 was sleeping in the scanner per his self report, 3) failure of the positive control modulation (light flux) to evoke a response in subject S03, and 4) the difficulty of interpreting any observed response to the melanopsin modulation, given that the modulation also stimulated the penumbral cones.</p>
<p><b><br></b></p><p><b>Tables</b></p>
<p><strong>Table S1 [Table_S1.xlsx] | Spreadsheet of spectral power distributions. </strong>All modulations are unsigned difference spectra. To derive the displayed stimulus, they would be added to the background. Spectral power distributions have been splined to 1 nm wavelength spacing (measured at 2 nm wavelength bands).</p>
<p><strong>Table S2 [Table_S2.xlsx] | Spreadsheet of stimulus sequences (fMRI experiments)</strong>. Within a given BOLD fMRI run, subjects viewed 12 s segments. The order of frequencies was counterbalanced and is given in the columns. </p>
<p><strong>Table S3 </strong><strong>[Table_S3.xlsx] | Spreadsheet of stimulus sequences (pupil experiments)</strong>. Within a given pupillometry run, subjects viewed 45 sec trials. The sequence is given in the rows, modulations and run types per column. </p>
<p><strong>Table S4 [Table_S4.xlsx] | Demographic details about subjects.</strong></p>
<p><strong>Table S5 [Table_S5.xlsx] | Individual subject pupil measures. </strong>Corresponds to data shown in graphical form in Fig. 3b.</p>
<p><strong>Table S6 [Table_S6.xlsx] | Individual subject nulling measures.</strong> Corresponds to data shown in graphical form in Fig. 3a. Sheet 1 contains the nulling values for the ±32% L+M+S and melanopsin modulations (subjects S01-15). Sheet 2 contains the nulling values for the ±17% melanopsin modulations (subjects S01-03).</p><p><b><br></b></p><p><b>Data</b></p><p><b>Data S1 [Data_S1.tar.gz] | BOLD fMRI Data (L+M, L-M, S, 17% melanopsin, 2-64 Hz).</b> Beta effect size maps from each subject (as well as the mean EPI image), registered to the whole-brain, individual anatomical image in native subject space.<b> </b>See README.txt for details. [MD5 (Data_S1.tar.gz) = c17d1e8f872f78d2f7feefa860e7794d].</p><p><b>Data S2 [Data_S2.tar.gz] | BOLD fMRI Data (L+M, L-M, S, 17% melanopsin, 0.5-2 Hz).</b><b> </b>Beta effect size maps from each subject (as well as the mean EPI image), registered to the whole-brain, individual anatomical image in native subject space. See README.txt for details. [MD5 (Data_S2.tar.gz) = ce06eae027f0e550e077faf06871f27b].</p><p><b>Data S3 [Data_S3.tar.gz] | BOLD fMRI Data (L+M+S, 0.5-64 Hz).</b><b> </b>Beta effect size maps from each subject (as well as the mean EPI image), registered to the whole-brain, individual anatomical image in native subject space. See README.txt for details. [MD5 (Data_S3.tar.gz) = 8aa43a415a84bc09b56dbec8aa038e13].</p><p><b>Data S4 [Data_S4.tar.gz] | </b><b>BOLD fMRI Data (L*+M*, 2-64 Hz; scaled L+M, 0.5-64 Hz). </b>Beta effect size maps from each subject (as well as the mean EPI image), registered to the whole-brain, individual anatomical image in native subject space. See README.txt for details. [MD5 (Data_S4.tar.gz) = 8e8239784c5932ee7543cc335bdae046].</p><p><b>Data S5 [Data_S5.tar.gz] | </b><b>BOLD fMRI Data (Light flux, nulled and un-nulled melanopsin, L+M+S and L-M nulling contrast; 4 Hz). </b>Beta effect size maps from each subject (as well as the mean EPI image), registered to the whole-brain, individual anatomical image in native subject space. See README.txt for details. [MD5 (Data_S5.tar.gz) = 8b377ab28e99bf9eb9fbe8cb440ffc1c].</p
dlmoR: An open-source R package for the dim-light melatonin onset (DLMO) hockey-stick method
No full textThe dim-light melatonin onset (DLMO) is a commonly used circadian marker indicating the start time of evening melatonin synthesis in humans. Several quantitative techniques have been developed to determine DLMO from melatonin time series, including fixed- or variable-threshold techniques and the hockey-stick method developed by Danilenko et al. (2014). Here, we introduce dlmoR, an open-source (MIT License) implementation of the hockey-stick method written in R. Our clean-room implementation follows the original algorithm description, supported by iterative validation against the existing binary executable. We benchmarked dlmoR on 112 melatonin time series datasets from two independent studies (Heinrichs and Spitschan (2025); Blume et al. (2024)) and found high agreement with the reference implementation: mean discrepancies were − 1.5482 ± 21.7 minutes for the Heinrichs and Spitschan (2025) dataset and 1.165 ± 28.5 minutes for the Blume et al. (2024) dataset, with circular correlation coefficients of 0.964 and 0.986, respectively. Paired t-tests (p > 0.05) indicated no systematic difference or bias between methods. Beyond reproducing the hockey-stick algorithm, dlmoR adds capabilities absent from the original executable, including interactive visual diagnostics and bootstrapped confidence intervals, offering qualitative and quantitative views of estimation uncertainty. It supports programmatic, reproducible analysis of melatonin profiles, including batch processing and parameter manipulation. Leveraging this flexibility, we evaluated the sensitivity of the hockey-stick algorithm to controlled changes in sampling schedules, threshold levels, data completeness, and noise. Moderate changes, such as small timing jitter, limited data loss, or modest threshold shifts, kept estimates stable within ±10 minutes, whereas pronounced alterations to sampling schedules, large multi-point deletions, or substantial threshold changes delayed estimates by over 40 minutes or prevented estimation. This analysis reveals fundamental limitations in the algorithm’s internal mechanics, particularly in how it identifies the onset window and models the melatonin rise, and underscores the need for new uncertainty-aware approaches to DLMO estimation
Principles of open, transparent and reproducible science in author guidelines of sleep research and chronobiology journals
No full textBackground: "Open science" is an umbrella term describing various aspects of transparent and open science practices. The adoption of practices at different levels of the scientific process (e.g., individual researchers, laboratories, institutions) has been rapidly changing the scientific research landscape in the past years, but their uptake differs from discipline to discipline. Here, we asked to what extent journals in the field of sleep research and chronobiology encourage or even require following transparent and open science principles in their author guidelines. Methods: We scored the author guidelines of a comprehensive set of 27 sleep and chronobiology journals, including the major outlets in the field, using the standardised Transparency and Openness (TOP) Factor. The TOP Factor is a quantitative summary of the extent to which journals encourage or require following various aspects of open science, including data citation, data transparency, analysis code transparency, materials transparency, design and analysis guidelines, study pre-registration, analysis plan pre-registration, replication, registered reports, and the use of open science badges. Results: Across the 27 journals, we find low values on the TOP Factor (median [25 th, 75 th percentile] 3 [1, 3], min. 0, max. 9, out of a total possible score of 29) in sleep research and chronobiology journals. Conclusions: Our findings suggest an opportunity for sleep research and chronobiology journals to further support recent developments in transparent and open science by implementing transparency and openness principles in their author guidelines
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
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