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Online sex advertisements (sex ads) have been linked to many U.S. sex trafficking cases. However, since the closure of the dominant website, Backpage.com (Backpage), many competing sites have emerged that are hosted in countries where U.S. law enforcement organizations have no jurisdiction. Although the online ecosystem has changed significantly, very little research uses data from sites other than Backpage, and even less uses data from multiple sites. This paper presents an anonymized dataset derived from the text and image artifacts of more than 10 million sex ads. By making this dataset publicly available, we aim to reduce barriers to entry for researchers interested in conducting data-driven counter-trafficking research. The dataset can be used to test hypotheses related to sex ads and intersite connectivity, understand the posting processes employed by prominent sites in the current online sex ad ecosystem, and develop multidisciplinary approaches for estimating ad legitimacy. Progress in any of these areas can result in potentially lifesaving interventions for ST victims. 

Restricted elevational ranges are common across tropical montane species, but the mechanisms generating and maintaining these patterns remain poorly resolved. A long-standing hypothesis is that specialized thermal physiology explains these distributions. However, biotic factors such as habitat and interspecific competition have also been proposed to limit tropical species’ elevational ranges. We combined point-level abundances, respirometry-based measurements of metabolic rate, habitat surveys and playback experiments to simultaneously test these three hypotheses for four species of Central American cloud forest songbirds. Contrary to the physiological hypothesis, we found no evidence that thermoregulatory costs constrain species distributions. Instead, thermal conditions across each species’ elevational range remained well within sustainable limits, staying ≤65% of hypothesized thresholds for tropical birds, even at the highest elevations. By contrast, we found some support for a combined role of habitat and competition in shaping elevational ranges. In one related species pair, the dominant lower-elevation species appears restricted by microhabitat, while the higher-elevation species is likely prevented from expanding downslope by the presence of this congener. Taken together, we conclude that thermoregulatory costs are an inadequate explanation for elevational range limits of tropical birds at our site and suggest that biotic factors can be key in shaping these distributions. We provide a Spanish translation of the Abstract in the supplementary materials. 

Many biological processes involve transport and organization of inclusions in thin fluid interfaces. A key aspect of these assemblies is the active dissipative stresses applied from the inclusions to the fluid interface, resulting in long-range active interfacial flows. We study the effect of these active flows on the self-organization of rod-like inclusions in the interface. Specifically, we consider a di- lute suspension of Brownian rods of length L, embedded in a thin fluid interface of 2D viscosity ηm and surrounded on both sides with 3D fluid domains of viscosity ηf . The momentum transfer from the interfacial flows to the surrounding fluids occurs over length l0 = ηm/ηf , known as Saffman- Delbru ̈ck length. We use zeroth, first and second moments of Smoluchowski equation to obtain the conservation equations for concentration, polar order and nematic order fields, and use linear stability analysis and continuum simulations to study the dynamic variations of these fields as a function of L/l0, the ratio of active to thermal stresses, and the dimensionless self-propulsion velocity of the embedded particles. We find that at sufficiently large activities, the suspensions of active extensile stress (pusher) with no directed motion undergo a finite wavelength nematic ordering, with the length of the ordered domains decreasing with increasing L/l0. The ordering transition is hindered with further increases in L/l0. In contrast, the suspensions with active contractile stress (puller) remain uniform with variations of activity. We notice that the self-propulsion velocity results in significant concentration fluctuations and changes in the size of the order domains that depend on L/l0. Our re- search highlights the role of hydrodynamic interactions in the self-organization of active inclusions on biological interfaces.