When the black sheep is not so «black». Social comparison as a standard for ingroup evaluation in classrooms

Previous research (Marques & Levine, 2016) suggests that the black sheep effect refers to the tendency of people to evaluate ingroup deviants members more negatively than outgroup deviants members. School students (N = 60) evaluated negative and positive performances attributed respectively to ingroup and outgroup members (unfavorable comparison) and negative performances attributed to both ingroup and outgroup members (neutral comparison). Results show that negative performances from ingroup members are less devaluated in the unfavorable comparisons condition than in the neutral comparisons condition and this effect is moderated by identification with their own school. Moreover, results show that in the unfavorable comparison condition students perceived a greater threat to their social identity than in the neutral comparison condition. The implications of these results are discussed in relation to the black sheep categorization and ingroup bias in a school context

On the Role of Serial Correlation and Field Significance in Detecting Changes in Extreme Precipitation Frequency

Statistical trend analyses of observed precipitation (P) time series are key to validate theoretical arguments and climate projections suggesting that extreme P will increase in a warmer climate. Recent work warned about possible misinterpretation of trend tests if the presence of serial correlation and field significance are not considered. Here, we investigate these two aspects focusing on extreme P frequencies derived from 100-year daily records of 1,087 worldwide gauges of the Global Historical Climatology Network. For this aim, we perform Monte Carlo experiments based on count time series generated with the Poisson integer autoregressive model and characterized by different sample size, level of autocorrelation, and trend magnitude. The main results are as follows. (a) Empirical autocorrelations are consistent with those of uncorrelated and stationary or nonstationary count time series, while empirical trends cannot be explained as the exclusive effect of autocorrelation; incorporating the impact of serial correlation in trend tests on extreme P frequency has then limited impacts on tests' performance. (b) Accounting for field significance improves interpretation of test results by limiting type-I errors, but it also decreases test power; results of local tests could complement field significance outcomes and help identify weak trend signals where several trends of coherent sign are detected. (c) Based on these findings, evident patterns of statistically significant increasing (decreasing) trends emerge in central and eastern North America, northern Eurasia, and central Australia (southwestern America, southern Europe, and southern Australia). The methodological insights of this work support trend analyses of any hydroclimatic variable

How much green roofs and rainwater harvesting systems can contribute to urban flood mitigation?

Increased urbanization combined with the intensification of short rainfall events has worsened the urban flood issue. Among the different blue-green solutions to mitigate pluvial floods, green roofs (GR) and rainwater harvesting (RWH) have been investigated as sustainable systems to reduce runoff from rooftops. Their flood mitigation capacity, however, has been estimated mostly at building-scale. Following the need to estimate discharge reduction at large scale over entire cities, we simulated the installation of (extensive, intensive and multilayer blue) GRs on flat roofs and RWH systems for sloped ones. Performances of such systems were investigated in selected cities, representing different climate regimes. Although at building-scale GRs showed higher retention capacity, the cost-efficiency analysis highlights that at large-scale RWH tanks ensure higher retention with lower costs, due to rooftop distribution. The coupled system of multilayer blue-GRs and RWH tanks guarantees a discharge reduction of 5% even during extreme events

Measuring Dynamics of Scattering Centers in the Ocular Fundus

The study is focused on the analysis of the diffusing-wave-spectroscopy signalrecorded invivo on the ocular fundus of a rabbit eye. The motion of the scattered sites wasmeasured as a function of the pressure exerted by a Goldmann contact lens and during themoderate temperature increase induced by a therapeutic laser diode. Temporal fluctuations ofthe signal revel motion of molecules and thus changes in tissues temperature andchorioretinal blood velocity. Experimental results show the ability of the system to detectmotion of the scattering sites in the ocular fundus layers during variations of the ocularpressure and laser heating

Practical Experiences of a Smart Livestock Location Monitoring System leveraging GNSS, LoRaWAN and Cloud Services.

Livestock farming is, in most cases in Europe, unsupervised, thus making it difficult to ensure adequate control of the position of the animals for the improvement of animal welfare. In addition, the geographical areas involved in livestock grazing usually have difficult access with harsh orography and lack of communications infrastructure, thus the need to provide a low-power livestock localization and monitoring system is of paramount importance, which is crucial not for a sustainable agriculture, but also for the protection of native breeds and meats thanks to their controlled supervision. In this context, this work presents an Internet of things (IoT)-based system integrating low-power wide area (LPWA) technology, cloud and virtualization services to provide real-time livestock location monitoring. Taking into account the constraints coming from the environment in terms of energy supply and network connectivity, our proposed system is based on a wearable device equipped with inertial sensors, Global Positioning System (GPS) receiver and LoRaWAN transceiver, which can provide a satisfactory compromise between performance, cost and energy consumption. At first, this article provides the state-of-the-art localization techniques and technologies applied to smart livestock. Then, we proceed to provide the hardware and firmware co-design to achieve very low energy consumption, thus providing a significant positive impact to the battery life. The proposed platform has been evaluated in a pilot test in the Northern part of Italy, evaluating different configurations in terms of sampling period, experimental duration and number of devices. The results are analyzed and discussed for packe delivery ratio, energy consumption, localization accuracy, battery discharge measurement and delay

Resonant optical control of the structural distortions that drive ultrafast demagnetization in Cr2_2O3_3

We study how the color and polarization of ultrashort pulses of visible light can be used to control the demagnetization processes of the antiferromagnetic insulator Cr$_2$O$_3$. We utilize time-resolved second harmonic generation (SHG) to probe how changes in the magnetic and structural state evolve in time. We show that, varying the pump photon-energy to excite either localized transitions within the Cr or charge transfer states, leads to markedly different dynamics. Through a full polarization analysis of the SHG signal, symmetry considerations and density functional theory calculations, we show that, in the non-equilibrium state, SHG is sensitive to {\em both} lattice displacements and changes to the magnetic order, which allows us to conclude that different excited states couple to phonon modes of different symmetries. Furthermore, the spin-scattering rate depends on the induced distortion, enabling us to control the timescale for the demagnetization process. Our results suggest that selective photoexcitation of antiferromagnetic insulators allows fast and efficient manipulation of their magnetic state.Comment: 7 pages, 5 figure

Xanthones from Polygala alpestris (Rchb.)

Bioactivity-guided fractionation of Polygala alpestris L. (Rchb.) extracts led to the identification of two new xanthones, 1,3,7-trihydroxy-2,6-dimethoxyxanthone (1) and 2,3-methylenedioxy-4,7-dihydroxyxanthone (2). In addition five known compounds 3,4-dimethoxy-1,7-dihydroxyxanthone (3), 1,3-dihydroxy-7-methoxyxanthone (4), 1,7-dihydroxy-2,3-dimethoxyxanthone (5), 3′,6-O-disinapoyl sucrose (6) and 3′,5′-dimethoxybiphenyl-4-olo (7) were isolated. The structures of the isolated compounds were established by means of high resolution mass spectrometry, mono- and bi-dimensional NMR spectroscopy. All isolated compounds were tested for cytotoxic activity against three tumor cell lines (LoVo, HL-60, K 562)

Quiescent low-mass galaxies observed by JWST in the Epoch of Reionization

The surprising JWST discovery of a quiescent, low-mass ($M_\star=10^{8.7} \rm M_\odot$) galaxy at redshift $z=7.3$ (JADES-GS-z7-01-QU) represents a unique opportunity to study the imprint of feedback processes on early galaxy evolution. We build a sample of 130 low-mass ($M_\star\lesssim 10^{9.5} \rm M_\odot$) galaxies from the SERRA cosmological zoom-in simulations, which show a feedback-regulated, bursty star formation history (SFH). The fraction of time spent in an active phase increases with the stellar mass from $f_{duty}\approx 0.6$ at $M_\star\approx 10^{7.5} \rm M_\odot$ to $\approx 0.99$ at $M_\star\geq 10^{9} \rm M_\odot$, and it is in agreement with the value $f_{duty}\approx 0.75$ estimated for JADES-GS-z7-01-QU. On average, 30% of the galaxies are quiescent in the range $6 < z < 8.4$; they become the dominant population at $M_\star\lesssim 10^{8.3} \rm M_\odot$. However, none of these quiescent systems matches the Spectral Energy Distribution of JADES-GS-z7-01-QU, unless their SFH is artificially truncated a few Myr after the main star formation peak. As supernova feedback can only act on a longer timescale ($\gtrsim 30 \rm \, Myr$), this implies that the observed abrupt quenching must be caused by a faster physical mechanism, such as radiation-driven winds.Comment: submitted to ApJ Letters, 5 pages, 4 figure

Dwarf satellites of high-z Lyman Break Galaxies: a free lunch for JWST

We show that the James Webb Space Telescope will be able to detect dwarf satellites of high-$z$ Lyman Break Galaxies (LBGs). To this aim, we use cosmological simulations following the evolution of a typical $M_\star\simeq10^{10}\rm M_\odot$ LBG up to $z\simeq6$, and analyse the observational properties of its five satellite dwarf galaxies ($10^7{\rm M_\odot}<M_\star<10^9{\rm M_\odot}$). Modelling their stellar emission and dust attenuation, we reconstruct their rest-frame UV-optical spectra for $6<z<6.5$. JWST/NIRCam synthetic images show that the satellites can be spatially resolved from their host, and their emission is detectable by planned deep surveys. Moreover, we build synthetic spectral energy distributions and colour-magnitude diagrams for the satellites. We conclude that the color $\rm F200W-F356W$ is a powerful diagnostic tool for understanding their physical properties once they have been identified. For example, $\rm F200W-F356W~\lesssim-0.25$ can be used to identify star-bursting ($\rm SFR\sim5~M_\odot yr^{-1}$), low-mass ($M_\star\lesssim5\times 10^8\rm M_\odot$) systems, with $\sim80\%$ of their stars being young and metal-poor ($\log(Z_\star/Z_\odot) < -0.5$).Comment: 8 pages, 3 figures, accepted for publication in ApJ