The effects of social norms on motivation crowding: experimental evidence from the Tibetan Plateau

A growing literature examines conditions under which financial incentives for behavior change can undermine "crowd out" or reinforce ("crowd in") other sources of motivation for the behavior in question. Some of this literature points to a potential role of social norms, but it has not attempted to quantify that role. We present an interdisciplinary model from economics and communication science that measures the effects of financial incentives on social norms and their joint effects on behavior, including after incentives have ended. In a framed field experiment with Tibetan herders in Qinghai, China, we find that a temporary payment for participation in a patrol against illegal wildlife trapping reinforces a perceived injunctive norm that this conservation behavior meets with social approval. This norm remains heightened even after the payment has ended, continuing to positively influence the decision to participate in anti-trapping patrols in the experiment. This finding suggests that, under certain circumstances, a carefully framed incentive for conservation behavior can support injunctive norms in favor of conservation behavior.USDA National Institute of Food and Agriculture, Hatch project [MICL02244, MICL02173, MICL02362]; National Science Foundation [SMA-1328503]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Pathogenic Pseudorabies Virus, China, 2012

In 2012, an unprecedented large-scale outbreak of disease in pigs in China caused great economic losses to the swine industry. Isolates from pseudorabies virus epidemics in swine herds were characterized. Evidence confirmed that the pathogenic pseudorabies virus was the etiologic agent of this epidemic

The MALATANG Survey : Dense Gas and Star Formation from High Transition HCN and HCO+ maps of NGC253

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2020 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.To study the high-transition dense-gas tracers and their relationships to the star formation of the inner $\sim$ 2 kpc circumnuclear region of NGC253, we present HCN $J=4-3$ and HCO$^+ J=4-3$ maps obtained with the James Clerk Maxwell Telescope (JCMT). With the spatially resolved data, we compute the concentration indices $r_{90}/r_{50}$ for the different tracers. HCN and HCO$^+$ 4-3 emission features tend to be centrally concentrated, which is in contrast to the shallower distribution of CO 1-0 and the stellar component. The dense-gas fraction ($f_\text{dense}$, traced by the velocity-integrated-intensity ratios of HCN/CO and HCO$^+$/CO) and the ratio $R_\text{31}$ (CO 3-2/1-0) decline towards larger galactocentric distances, but increase with higher SFR surface density. The radial variation and the large scatter of $f_\text{dense}$ and $R_\text{31}$ imply distinct physical conditions in different regions of the galactic disc. The relationships of $f_\text{dense}$ versus $\Sigma_\text{stellar}$, and SFE$_\text{dense}$ versus $\Sigma_\text{stellar}$ are explored. SFE$_\text{dense}$ increases with higher $\Sigma_\text{stellar}$ in this galaxy, which is inconsistent with previous work that used HCN 1-0 data. This implies that existing stellar components might have different effects on the high-$J$ HCN and HCO$^+$ than their low-$J$ emission. We also find that SFE$_\text{dense}$ seems to be decreasing with higher $f_\text{dense}$, which is consistent with previous works, and it suggests that the ability of the dense gas to form stars diminishes when the average density of the gas increases. This is expected in a scenario where only the regions with high-density contrast collapse and form stars.Peer reviewe

ATOMS : ALMA three-millimeter observations of massive star-forming regions - VII. A catalogue of SiO clumps from ACA observations

To understand the nature of SiO emission, we conducted ACA observations of the SiO (2-1) lines toward 146 massive star-forming regions, as part of the ALMA Three-millimeter Observations of Massive Star-forming regions (ATOMS) survey. We detected SiO emission in 128 (87.7 per cent) sources and identified 171 SiO clumps, 105 of which are spatially separated from 3 mm continuum emission. A large amount of the SiO line profiles (60 per cent) are non-Gaussian. The velocity dispersion of the SiO lines ranges from 0.3 to 5.43 km s(-1). In 63 sources the SiO clumps are associated with H II regions characterized by H40 alpha emission. We find that 68 per cent (116) of the SiO clumps are associated with strong outflows. The median velocity dispersion of the SiO line for outflow sources and non-outflow sources is 1.91 km s(-1) and 0.99 km s(-1), respectively. These results indicate that outflow activities could be connected to strongly shocked gas. The velocity dispersion and [SiO]/[(HCO+)-C-13] intensity ratio do not show any correlation with the dust temperature and particle number density of clumps. We find a positive correlation between the SiO line luminosity and the bolometric luminosity, implying stronger shock activities are associated with more luminous protoclusters. The SiO clumps in associations with HII regions were found to show a steeper feature in Lsio/Lbol. The SiO line luminosity and the fraction of shocked gas have no apparent evidence of correlation with the evolutionary stages traced by luminosity to mass ratio (L-bol/M).Peer reviewe

ATOMS : ALMA Three-millimeter Observations of Massive Star-forming regions - VIII. A search for hot cores by using C2H5CN, CH3OCHO, and CH3OH lines

Hot cores characterized by rich lines of complex organic molecules are considered as ideal sites for investigating the physical and chemical environments of massive star formation. We present a search for hot cores by using typical nitrogen- and oxygen-bearing complex organic molecules (C2H5CN, CH3OCHO, and CH3OH), based on ALMA Three-millimeter Observations of Massive Star-forming regions (ATOMS). The angular resolutions and line sensitivities of the ALMA observations are better than 2 arcsec and 10 mJy beam(-1), respectively. A total of 60 hot cores are identified with 45 being newly detected, in which the complex organic molecules have high gas temperatures (> 100 K) and hot cores have small source sizes (< 0.1 pc). So far, this is the largest sample of hot cores observed with similar angular resolution and spectral coverage. The observations have also shown nitrogen and oxygen differentiation in both line emission and gas distribution in 29 hot cores. Column densities of CH3OH and CH3OCHO increase as rotation temperatures rise. The column density of CH3OCHO correlates tightly with that of CH3OH. The pathways for production of different species are discussed. Based on the spatial position difference between hot cores and ultracompact H ii (UC H ii) regions, we conclude that 24 hot cores are externally heated, while the other hot cores are internally heated. The observations presented here will potentially help establish a hot core template for studying massive star formation and astrochemistry.Peer reviewe

ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP) : How Do Dense Core Properties Affect the Multiplicity of Protostars?

During the transition phase from a prestellar to a protostellar cloud core, one or several protostars can form within a single gas core. The detailed physical processes of this transition, however, remain unclear. We present 1.3 mm dust continuum and molecular line observations with the Atacama Large Millimeter/submillimeter Array toward 43 protostellar cores in the Orion molecular cloud complex (lambda Orionis, Orion B, and Orion A) with an angular resolution of similar to 0.'' 35 (similar to 140 au). In total, we detect 13 binary/multiple systems. We derive an overall multiplicity frequency (MF) of 28% +/- 4% and a companion star fraction (CSF) of 51% +/- 6%, over a separation range of 300-8900 au. The median separation of companions is about 2100 au. The occurrence of stellar multiplicity may depend on the physical characteristics of the dense cores. Notably, those containing binary/multiple systems tend to show a higher gas density and Mach number than cores forming single stars. The integral-shaped filament of the Orion A giant molecular cloud (GMC), which has the highest gas density and hosts high-mass star formation in its central region (the Orion Nebula cluster), shows the highest MF and CSF among the Orion GMCs. In contrast, the lambda Orionis GMC has a lower MF and CSF than the Orion B and Orion A GMCs, indicating that feedback from H ii regions may suppress the formation of multiple systems. We also find that the protostars comprising a binary/multiple system are usually at different evolutionary stages.Peer reviewe

ATOMS : ALMA Three-millimeter Observations of Massive Star-forming regions - XI. From inflow to infall in hub-filament systems

We investigate the presence of hub-filament systems in a large sample of 146 active proto-clusters, using (HCO+)-C-13 J = 1-0 molecular line data obtained from the ATOMS survey. We find that filaments are ubiquitous in proto-clusters, and hub-filament systems are very common from dense core scales (similar to 0.1 pc) to clump/cloud scales (similar to 1-10 pc). The proportion of proto-clusters containing hub-filament systems decreases with increasing dust temperature (T-d) and luminosity-to-mass ratios (L/M) of clumps, indicating that stellar feedback from H ii regions gradually destroys the hub-filament systems as proto-clusters evolve. Clear velocity gradients are seen along the longest filaments with a mean velocity gradient of 8.71 km s(-1) pc(-1) and a median velocity gradient of 5.54 km s(-1) pc(-1). We find that velocity gradients are small for filament lengths larger than similar to 1 pc, probably hinting at the existence of inertial inflows, although we cannot determine whether the latter are driven by large-scale turbulence or large-scale gravitational contraction. In contrast, velocity gradients below similar to 1 pc dramatically increase as filament lengths decrease, indicating that the gravity of the hubs or cores starts to dominate gas infall at small scales. We suggest that self-similar hub-filament systems and filamentary accretion at all scales may play a key role in high-mass star formation.Peer reviewe

ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP) : Detection of Extremely High-density Compact Structure of Prestellar Cores and Multiple Substructures Within

Prestellar cores are self-gravitating dense and cold structures within molecular clouds where future stars are born. They are expected, at the stage of transitioning to the protostellar phase, to harbor centrally concentrated dense (sub)structures that will seed the formation of a new star or the binary/multiple stellar systems. Characterizing this critical stage of evolution is key to our understanding of star formation. In this work, we report the detection of high-density (sub)structures on the thousand-astronomical-unit (au) scale in a sample of dense prestellar cores. Through our recent ALMA observations toward the Orion Planck Galactic Cold Clumps, we have found five extremely dense prestellar cores, which have centrally concentrated regions of similar to 2000 au in size, and several 10(7) cm(-3) in average density. Masses of these centrally dense regions are in the range of 0.30 to 6.89 M. For the first time, our higher resolution observations (0.8 '' similar to 320 au) further reveal that one of the cores shows clear signatures of fragmentation; such individual substructures/fragments have sizes of 800-1700 au, masses of 0.08 to 0.84 M, densities of 2 - 8 x 10(7) cm(-3), and separations of similar to 1200 au. The substructures are massive enough (greater than or similar to 0.1 M) to form young stellar objects and are likely examples of the earliest stage of stellar embryos that can lead to widely (similar to 1200 au) separated multiple systems.Peer reviewe