dataesr/scientific-paragraphs-categorization huggingface dataset:
Finally, because studies showed that eye gaze direction could play a role in outgroup perception (e. g. Richeson & Trawalter, 2008) , we also manipulated gaze direction. Accordingly, in addition to having faces looking at the camera (i. e. gaze direction in front), we will also provide each face with the gaze direction on the left and on the right. In addition to collecting face pictures and prototypicality ratings, we also gathered ratings on two subjective dimensions: attractiveness and willingness to approach/avoid the faces. We chose these two dimensions because researchers could be interested in controlling them and because it will enable us to test whether the faces composing our database are perceived as we predict they should be. First, we could expect that the more faces are prototypical of Caucasian faces (as compared with North African faces), the more they will be perceived as attractive by Caucasian individuals  (Kniffin, Wansink, Griskevicius & Wilson, 2014; Ratner, Dotsch, Wigboldus, van Knippenberg & Amodio, 2014).
Each photo was taken with a white uniform background and participants were standing three meters from the camera. We took three pictures of each participant, with three different gaze directions (i. e. right, frontal, and left). To standardise the direction of their eye gaze and in order for them to change their eye gaze direction while keeping their head facing the camera, participants were asked to look at crosses drawn on a wall on the left or on the right of the camera. Participants were also asked to display a neutral emotion. Image processing. The database contains 441 portrait images of 147 male faces with three different gaze directions. Images are stored in a JPEG format and have been post treated for harmonisation. Accordingly, we removed all the remaining distinctive signs or imperfections with Photoshop.
CaNAFF Database Validation Participants. Sixty-eight participants took part in the validation study (M age = 22. 09, SD age = 3. 04, 62 females). Participants were students in a psychology master's degree and came in exchange for course credits. Because many studies on intergroup relations between different ethnicities include a large majority of Caucasian participants (see  Rudman, Feinberg & Fairchild, 2002 , for a similar observation), we decided to keep only participants who categorised themselves as Caucasians; otherwise, non-Caucasian participants could have a different judgement and bias the database validation. Accordingly, data from 13 participants were removed from the analysis. Procedure. For this validation, we collected four measures: emotional neutrality, prototypicality, attractiveness, and willingness to approach or avoid the face.
These ratings were collected by creating two groups of participants. Because subtle emotional expressions could change from picture to picture, a first group of 25 participants evaluated the emotional neutrality of the 441 pictures. Each photo was seen independently (i. e. each participant saw all the photos separately, with the three different gaze directions), and participants had to assess the emotional expression of the face (from -50 = positive to +50 = negative, the middle of the scale representing neutrality; here and everywhere below, participants did not see these numbers only the anchors; these numbers only reflect how responses were coded). Photo order was randomised across participants. Because the other dimensions should have little reason to change drastically from picture to picture, a second group of 30 participants evaluated these dimensions for each of the 147 individuals composing our database.
Results For all our data analysis, we used R (version 3. 4. 2, 2017; R Core Team, 2012) and the lme4 package  (version 1. 1, 2016; Bates, Maechler & Bolker, 2015). P-values were obtained by Kenward-Rogers approximation (car package, version 2. 1. 6, 2017;  Fox & Weisberg, 2011). When possible, we applied mixed model analyses  (Judd, Westfall & Kenny, 2012) , which allows for analysing continuous withinparticipants variables. First, we tested whether levels of emotional expression, attractiveness, and willingness to approach/avoid differed from neutrality. To do so, we ran three separate mixed model analyses to test whether the mean across faces differed from zero. Second, we tested the relationship between prototypicality and the previous variables (i. e. emotional neutrality, attractiveness, and approach/avoidance willingness).
Conversely, because our aim was not to generalise our results to other stimuli (i. e. other photos of faces than those composing our database), we did not use stimuli as a random factor. Finally, for all the rating dimensions, we calculated the intraclass correlations (ICC 2. 1 and ICC 2. k;  Shrout & Fleiss, 1979)  as indices for interrater reliability (Table  1 ). 2 It should be noted that ICC 2. k can generally be interpreted as Cronbach's alpha.
Global Features As a reminder, in our database we aimed for faces displaying a neutral emotional expression. All faces taken together (i. e. 147 faces with three different gaze directions), the overall emotion was not significantly different from neutrality (M = -0. 49, SD = 4. 75), t(24. 00) = 0. 61, p =. 55. 3 Similarly, if we split faces by gaze directions, we can see that faces with eye-gaze directed towards the camera (M = 0. 98, SD = 5. 11), t(23. 99) = 0. 93, p =. 36, as well as faces with gaze directions respectively on the right (M = -0. 96, SD = 5. 18), t(23. 99) = 1. 04, p =. 31 and on the left (M = -1. 50, SD = 4. 92), t(23. 99) = 1. 47, p =. 15, all displayed an emotion not different from neutrality. Regarding attractiveness, overall our faces were categorised as relatively unattractive (M = -15.
Prototypicality and Its Relationship to Perception of the Faces Our goal was to create a database of Caucasian and North African faces, prototypical of faces encountered in a French environment. Having preselected these faces in relation to their presupposed Caucasian and North African category memberships, as predicted, two different groups of faces emerged from the prototypicality scale (Figure  2 ). Overall, preselected Caucasian faces (N = 75) were perceived as more prototypical of their category (M = -26. 86, SD = 8. 28) than preselected North African faces (N = 72; M = 18. 24, SD = 9. 21), t(145) = 5. 97, p <. 001, h p ² =. 20. There was no relation between face prototypicality and emotional neutrality perception, b = 0. 02, t(145) = 1. 24, p =. 22, h p ² =. 01 (Figure  3 , top panel).
Discussion The goal of this contribution was to introduce a new database of Caucasian and North African faces, the CaNAFF, a database of faces of people living in France. To do so, we photographed 147 faces of French individuals under three different eye gaze directions for a total of 441 photos. Subsequently, to validate our database, we submitted these photos to a sample of Caucasian students to assess these faces on emotional neutrality, prototypicality, attractiveness, and approach/avoidance willingness.
Similarity with the Pre-existing Literature Our results are coherent with the intergroup literature. First, previous work has shown that people find members of their ingroup more attractive than people from an outgroup (e. g. Kniffin et al. , 2014; Ratner et al. , 2014). Therefore, given that North Africans can constitute an outgroup for participants who took part in the validation of the database, it is coherent to find that our North African origin faces were evaluated as being less attractive than the faces of Caucasian origin. Second, previous work using approach/avoidance paradigms has also shown that participants more easily approached members from their ingroup than people from an outgroup, while the reverse is true for avoidance (e. g. Paladino & Castelli, 2008). Therefore, it is also coherent to find that our participants reported a higher willingness to avoid faces of North African origin compared to faces of Caucasian origin.
In addition, it is also noteworthy that we already used the faces from this database in the context of an indirect measure involving these two groups. In three recent replications of the stereotype misperception task  (Krieglmeyer & Sherman, 2012)  with Caucasian participants, we systematically found priming effects coherent with an indirect ingroup bias in favour of (our) Caucasian faces over (our) North African faces. This result is in line with previous work demonstrating an indirect ingroup bias when relying on these groups (e. g. Mange, Sharvit, Margas & Sénémeaud, 2016)  and therefore contributes in suggesting that our database can be used to study implicit cognition. It is worth mentioning that we did not rely on a full ingroup-outgroup design (i. e. with members of both groups as participants and targets;  Judd & Park, 1993) , so strictly speaking, our results do not demonstrate that these effects can really be interpreted as ingroup versus outgroup effects.
Contribution to Scientific Research To the best of our knowledge, this is the first database of French and North African faces from a French environment. By having easy (and free) access to this database (all the information are available on this link: https://osf. io/274ry/), researchers will have an alternative to the use of foreign databases (e. g. the Radboud Faces Database;    Langner et al. , 2010)  or unstandardised stimuli (e. g. stimuli found on search engines) when they want to study (quick and spontaneous) reactions towards Caucasian versus North African groups. In addition, researchers will have the opportunity to study these reactions while being able to select features related to the level of emotional neutrality, prototypicality, attractiveness, or approach/ avoidance willingness.
Like in other countries in Europe, North African/Arab individuals are sometimes perceived as highly threatening (e. g. ,  Mange et al. , 2016). At a time of multiple terrorist attacks and the resurgence of extremist groups, such a database could be useful for studies on stereotypes or prejudices against North African people. Having preselected these faces in relation to their presupposed Caucasian and North African category memberships, it is interesting to see that, within these categories, faces can be perceived as more or less close to the vision of what a Caucasian or a North African individual should be (see also  Blair, Judd, Sadler & Jenkins, 2002). Focusing on intergroup relations between Black and White people, studies have already tried to modify the degree of face prototypicality by using, for example, morphs (e.
g. ,  Freeman, Penner, Saperstein, Scheutz & Ambady, 2011). Dealing with real faces, other studies showed that people who had more Afrocentric features were more likely to be associated with stereotypical traits of Black people rather than counter-stereotypical traits  (Blair et al. , 2002). Using again real faces, our database could be useful to test whether this kind of result can be reproduced with the two groups we used here. Therefore, this new database will be useful not only for studying the relations between Caucasian and North African populations in France, but also for studying the influence of facial prototypicality (i. e. facial likeness with the group prototype) in intergroup relations. No previous study has examined the role of skin tone alone (i. e. controlling for other perceptual features) in the perception of North African prototypicality and the associated stereotype of threat.
Limitations Despite the fact that we tried to standardise our database as much as possible, some limits can be mentioned. First of all, although our database includes two clusters of faces (i. e. North African and Caucasian faces), the degree of average prototypicality between the two groups is different. On average, the Caucasian faces were perceived as more prototypical than the North African faces. We can suggest two explanations for this difference. First, maybe the Caucasian faces were indeed objectively more prototypical of their group than North African faces. Second, it may have been more difficult for our (self-categorised French origin) participants to categorise a face as North African because the category itself is less well defined or because it could be socially more difficult to categorise someone as a member of a minority.
A second limitation is that, compared to some other databases (e. g. Chicago Face Database;  Ma et al. , 2015) , the CaNAFF only contains young male faces. In the future, it would be desirable to complete this database with female faces or older faces. Finally, the male/female ratio of our validation sample was unbalanced (62 females, 6 males). This ratio was not something we aimed for, but it reflects the usual ratio found in psychology universities in France; therefore, it fits the kind of sample many research rely on. That being said, and although it is unclear whether ratings of faces would differ according to participants gender, this was impossible to test with the current sample, considering the small number of male participants.
Conclusion The goal of this contribution was to introduce a new database of Caucasian and North African faces from French individuals. Researchers will be able to select and use available photos for free in their future research. This selection of Caucasian and North African faces can concern their level of emotional neutrality, prototypicality, attractiveness, and approach/avoidance willingness. We expect that this database will be a useful tool for scholars interested in implicit social cognition related to these two groups.
, 2014). This study provides a comprehensive and in-depth analysis of the aerosol optical properties in the Amazonian atmosphere. A continuous long-term dataset (2012 -2017) of different optical properties is provided. We especially focus on the impact of BB emissions from long-range transport and from regional/local open fires during the dry season. By using data from another central Amazonia remote sampling site, we extend our time series back to 2008 and provide the longest optical properties dataset measured in the Amazon rain forest. By this means, we are able to study the perturbations caused by El Niño Southern Oscillation (ENSO), which has been reported to cause drought all over the Amazon Basin (see Fig. S1 ), with increasing fire activity and forest degradation  (Aragão et al. , 2008; Lewis et al.
Another sampling site, ZF2 / TT34 tower, located 60 km NNW of Manaus (Fig. S2 ) has been the location of long-term aerosol observations and intensive measurement campaigns  (Rizzo et al. , 2013). Given that most of the air masses that reach the ZF2 site are the same that are transported over the ATTO site  (Pöhlker et al. , 2017a) , the ZF2 data is usually comparable to the ATTO data and the time series presented in this study can complement previous ZF2 time series already reported for the period 2008 -2011  (Rizzo et al. , 2013). Additionally, two intensive observation periods (IOP) and long-term measurements of the GoAmazon2014/5 experiment took place at several measurement sites in the Amazon Basin, including the ATTO site. More details can be found in  Martin et al. (2016 Martin et al.
6 m² g -1 ). The MAAP was generally operated at a flow rate of 10 L min -1 , but for some periods the flow rate was reduced to 8. 3 L min -1. According to  Müller et al. (2011) , the MAAP measures at a wavelength of 637 ± 1 nm, instead of the 670 nm reported in the instrument's manual. In our calculations, we use 637 nm as the default MAAP wavelength and do not apply any interpolation factor to scale up the data from 670 to 637 nm since it would be in the ~5 % range, which is within the instrument uncertainty. The total uncertainty of the MAAP absorption measurements is of the order of 10 % for 30-min average times  (Rizzo et al. , 2013). An Aethalometer was used to measure attenuation of light by aerosol particles at different wavelengths. This instrument uses a LED light source to irradiate an aerosol-laden quartz-fiber filter and a detector, located in the forward hemisphere, to measure the light transmission  (Hansen et al.
, 1984). The measured transmission is compared to a blank measurement in order to obtain a change in light transmission (attenuation). This attenuation is then converted to BC mass concentration by using a mass attenuation cross section that depends on the instrument model (14625 and 6837. 6 m² g -1 λ -1 for the AE31 and AE33 Aethalometer models, respectively). Aethalometer measurements started at the ATTO site in April 2012 using an Aethalometer model AE31 (Magee Scientific, Berkeley, USA). The instrument was operated at different flow rates during the measurement period (varying from 2. 0 to 3. 7 L min -1 ) and measured attenuation every 15 min. In January 2015, a new Aethalometer, model AE33  (Aerosol d. o. o. , Ljubljana, Slovenia) , was installed. The overlapping measurement time of the AE31 and the AE33 models (27 Nov to 15 Dec 2014) enabled the comparison of both datasets.
, 2003). Four avalanche photo-diode (APD) detectors are installed in the instrument to measure a) scattering, b) broadband incandescence (350 -800 nm), c) narrowband incandescence (630 -880 nm) and d) scattering with a split detector. Time dependent data is recorded from each particle as it passes through the laser beam. The ratio between broadband and narrowband signals can provide information on the particle's composition since it is related to the boiling point temperature of the sampled particles  (Schwarz et al. , 2006). The instrument was periodically calibrated using fullerene soot (Alfa Aesar Inc. ) as rBC reference material. A quadratic fit was applied to the recorded incandescence peak heights vs. the mass of mobility size-selected fullerene particles. The fullerene effective densities were taken from  Gysel et al.
A Nafion dryer was installed in front of the instrument in order to reduce the noise in the CO measurements, which are affected by the high relative humidity of the tropical forest air. Calibration and performance checks will be reported in an upcoming paper. The instrument samples at five different heights but we restrict our analysis to the data measured at 79 m. All CO measurements have been conducted on the walk-up tower. More details on the measurement setup can be found in  Winderlich et al. (2010). In order to calculate the BC enhancement ratios with respect to CO (ER BC ), we used a major axis estimation fit that was applied to the bivariate data  (Falster et al. , 2006)  where the slope represents the enhancement ratio. The 5 th percentiles were used as background values. Condensation nuclei (CN) number concentrations, N CN , and size distributions from 10 nm to 10 µm were continuously measured using several instruments including mobility and optical particle sizers (more details can be found in  Andreae et al.
However, this assumption is theoretically wrong and the BC-related å abs is very sensitive to the size of the particles  (Moosmüller et al. , 2011). Wang et al. (2016b)  proposed a method to calculate the wavelength dependence of the Ångström exponent (WDA) in order to estimate the BrC contribution to total light absorption by aerosol particles. They use the difference between two å abs calculated for two different wavelength pairs (440 -870 nm, and 675 -880 nm) using aerosol robotic network (AERONET) and Aethalometer data. We use a similar approach to retrieve WDA using Aethalometer data from the ATTO site. In this study the WDA is calculated as follows: WDA=å abs 370-950 -å abs 660-950 , where å abs 370-950 and å abs 660-950 correspond to the absorption Ångström exponents calculated for the 370 -950 and 660 -950 nm wavelength pairs, respectively.
Theoretical WDA values were calculated following conceptual Mie theory models for (i) polydisperse BC particles  (Mishchenko et al. , 1999) , and (ii) core-shell internally mixed monodisperse BC  (Bohren and Huffman, 1983). Calculated BC WDA thresholds, presented in Fig. S5 , were compared to the ambient data in order to retrieve the BrC contribution to light absorption. Characteristic BC core size distributions measured by the SP2 during the wet and dry season were used in the polydisperse BC-only model to retrieve extinction efficiency and single scattering albedo. The refractive indices used were 1. 95 -0. 79i for BC  (Bond and Bergstrom, 2006 ) and 1. 55 -0. 001i for the coating material  (Liu et al. , 2015). The latter value was only used for the internally mixed BC case. The BC core diameters used in the internally mixed case were  100, 125, 150, 175, 200, 225 , and 250 nm, with coating thickness to core size ratio from 0.
South American fire count data were retrieved from the satellite observations database available online by the Instituto Nacional de Pesquisas Espaciais (INPE), Brazil, at https://prodwwwqueimadas. dgi. inpe. br/bdqueimadas/, last access on 04 Apr 2017. The fire data covered the same period as the HYSPLIT clustering analysis period, January 2008 to June 2016. Fire counts were classified according to the corresponding BT cluster where they occurred at hourly resolution. The fire counts reported in this study were weighted according to the trajectory density as (trajectory counts) / 100 km 2. Since the fire count number depends on the amount of satellite data available, we use these data with caution and only as a qualitative reference. For an extended discussion on fire geographical locations and land cover types, see  Pöhlker et al.
Satellite data The aerosol optical depth (AOD) at 550 nm, measured by the moderate resolution imaging spectroradiometers (MODIS) on board of the satellites Terra and Aqua, was retrieved for two domains of interest (see Fig. 2a ): • DOI1: Over the Atlantic Ocean. Used to monitor the westward transport of BB aerosol particles from southern Africa, which is mostly emitted during the Amazon dry season, especially between August and September  (Das et al. , 2017). There is no guarantee that the observed aerosol over this area will necessarily reach the ATTO site, but it is used as an indication of LRT events from southern Africa that will likely reach the Amazon Basin. Boundaries: 30 W; 20 S; 10 W; 0 S. • DOI2: Over the southern Amazon. Used to monitor BB in this region where fire activity is related to deforestation and agriculture-related activities.
Boundaries: 58 W; 14 S; 40 W; 8 S. The MODIS products can be found online on the Goddard Earth Science Data and Information Services Center at https://giovanni. gsfc. nasa. gov/giovanni/, last access on 17 Jul 2017, (GES-DISC, 2017). Terra and Aqua data were averaged over the two different domains. The averaged AOD at 550 nm time series corresponding to DOI1 and DOI2 can be found in Fig. 2b. The seasonality observed for both datasets is similar but AOD for DOI1 (Atlantic Ocean) generally increased in August and decreased after the end of September with some peaks in January -February, especially in 2016. On the other hand, high AOD values in DOI2 (South Amazon), increased sharply in the beginning of September and decreased continuously until the middle of December with the exception of the dry season 2015 when high AOD was observed until February 2016.
Data treatment The analyzed data were averaged to 30-min intervals and corrected to standard temperature and pressure  (STP, 273. 15 K and 1013. 25 hPa). Furthermore, the scattering data were interpolated to 637 nm to compare directly to the absorption data obtained by the MAAP, in order to avoid the uncertainty associated with the absorption spectral dependence calculation. The time periods of major and medium dust influence were taken from a study by  Moran-Zuloaga et al. (2017). During the dry season, BB pulses were segregated by using the 75 th percentile of σ ap 637 as a threshold. When examining correlations between independent measurements, we applied standardized major-axis estimations (SMA) by using the SMATR package  (Falster et al. , 2006)  in the statistical software environment R (R Development Core  Team, 2009).