Remarkable Sensitivity of Young Honey Bee Workers to Multiple Non-photic, Non-thermal, Forager Cues That Synchronize Their Daily Activity Rhythms

Honey bees live in colonies containing tens of thousands of workers that coordinate their activities to produce efficient colony-level behavior. In free-foraging colonies, nest bees are entrained to the forager daily phase of activity even when experiencing conflicting light-dark illumination regime, but little is known on the cues mediating this potent social synchronization. We monitored locomotor activity in an array of individually caged bees in which we manipulated the contact with neighbour bees. We used circular statistics and coupling function analyses to estimate the degree of social synchronization. We found that young bees in cages connected to cages housing foragers showed stronger rhythms, better synchronization with each other, higher coupling strength, and a phase more similar to that of the foragers compared to similar bees in unconnected cages. These findings suggest that close distance contacts are sufficient for social synchronization or that cage connection facilitated the propagation of time-giving social cues. Coupling strength was higher for bees placed on the same tray compared with bees at a similar distance but on a different tray, consistent with the hypothesis that substrate borne vibrations mediate phase synchronization. Additional manipulation of the contact between cages showed that social synchronization is better among bees in cages connected with tube with a single mesh partition compared to sealed tubes consistent with the notion that volatile cues act additively to substrate borne vibrations. These findings are consistent with self-organization models for social synchronization of activity rhythms and suggest that the circadian system of honey bees evolved remarkable sensitivity to non-photic, non-thermal, time giving entraining cues enabling them to tightly coordinate their behavior in the dark and constant physical environment of their nests.

Presence of red giant population in the foreground stellar sub-structure of the Small Magellanic Cloud

The eastern region of the Small Magellanic Cloud (SMC) is found to have a foreground stellar sub-structure, which is identified as a distance bimodality (∼ 12 kpc apart) in the previous studies using Red Clump (RC) stars. Interestingly, studies of Red Giant Branch (RGB) stars in the eastern SMC indicate a bimodal radial velocity (RV) distribution. In this study, we investigate the connection between these two bimodal distributions to better understand the nature and origin of the foreground stellar sub-structure in the eastern SMC. We use the Gaia EDR3 astrometric data and archival RV data of RGB stars for this study. We found a bimodal RV distribution of RGB stars (separated by ∼ 35–45 km s−1) in the eastern and south-western (SW) outer regions. The observed proper motion values of the lower and higher RV RGB components in the eastern regions are similar to those of the foreground and main-body RC stars respectively. This suggests that the two RGB populations in the eastern region are separated by a similar distance as those of the RC stars, and the RGB stars in the lower RV component are part of the foreground sub-structure. Based on the differences in the distance and RV of the two components, we estimated an approximate time of formation of this sub-structure as 307 ± 65 Myr ago. This is comparable with the values predicted by simulations for the recent epoch of tidal interaction between the Magellanic Clouds. Comparison of the observed properties of RGB stars, in the outer SW region, with N-body simulations shows that the higher RV component in the SW region is at a farther distance than the main body, indicating the presence of a stellar Counter-Bridge in the SW region of the SMC.

Evidence for a late glacial advance near the beginning of the Younger Dryas in western New York State: An event postdating the record for local Laurentide ice sheet recession

Widespread evidence of an unrecognized late glacial advance across preexisting moraines in western New York is confirmed by 40 14C ages and six new optically stimulated luminescence analyses between the Genesee Valley and the Cattaraugus Creek basin of eastern Lake Erie. The Late Wisconsin chronology is relatively unconstrained by local dating of moraines between Pennsylvania and Lake Ontario. Few published 14C ages record discrete events, unlike evidence in the upper Great Lakes and New England. The new 14C ages from wood in glacial tills along Buttermilk Creek south of Springville, New York, and reevaluation of numerous 14C ages from miscellaneous investigations in the Genesee Valley document a significant glacial advance into Cattaraugus and Livingston Counties between 13,000 and 13,300 cal yr B.P., near the Greenland Interstadial 1b (GI-1b) cooling leading into the transition from the Bölling-Alleröd to the Younger Dryas. The chronology from four widely distributed sites indicates that a Late Wisconsin advance spread till discontinuously over the surface, without significantly modifying the preexisting glacial topography. A short-lived advance by a partially grounded ice shelf best explains the evidence. The advance, ending 43 km south of Rochester and a similar distance south of Buffalo, overlaps the revised chronology for glacial Lake Iroquois, now considered to extend from ca. 14,800–13,000 cal yr B.P. The spread of the radiocarbon ages is similar to the well-known Two Creeks Forest Bed, which equates the event with the Two Rivers advance in Wisconsin.

Exploring the changing geographical pattern of international scientific collaborations through the prism of cities

Science is becoming increasingly international in terms of breaking down walls in its pursuit of high impact. Despite geographical location and distance still being major barriers for scientific collaboration, little is known about whether high-impact collaborations are similarly constrained by geography compared to collaborations of average impact. To address this question, we analyze Web of Science (WoS) data on international collaboration between global leader cities in science production. We report an increasing intensity of international city-city collaboration and find that average distance of collaboration of the strongest connections has slightly increased, but distance decay has remained stable over the last three decades. However, high-impact collaborations span large distances by following similar distance decay. This finding suggests that a larger geographical reach of research collaboration should be aimed for to support high-impact science. The creation of the European Research Area (ERA) represents an effective action that has deepened intracontinental research collaborations and the position of the European Union (EU) in global science. Yet, our results provide new evidence that global scientific leaders are not sufficiently collaborative in carrying out their big science projects.

GLACIER RETREAT DIFFERENCES IN CHILEAN CENTRAL ANDES AND THEIR RELATION WITH ANTHROPOGENIC BLACK CARBON POLLUTION

Black Carbon (BC) is indicated as the main atmospheric pollutant that obscures snow surfaces and absorbs solar energy, which accelerates the melting of ice/snow and produces glacier retreat. The case of Chile is of particular interest because it has most part of the Andean cryosphere, which has responded strongly to climate change through a retreat of their glaciers, having implications in the availability of freshwater for the inhabitants and economic activities. In this work, the aim was to investigate and quantify for the first time the impact that BC could have on the differences observed in the glacial retreat in the study area, decoupling this impact of the climatic and glaciological factors, through which it has not been possible to explain the difference in glacier behavior in the zone. In this case, two glaciers with comparable characteristics from the Central Andes of Chile were studied: Olivares Alpha Glacier (OAG) and Bello Glacier (BG). The spatio-temporal evolution (2004-2014) was studied using remote sensing images (Landsat). This information was analyzed together with measured data of BC concentrations in air and snow for the year 2014. Results showed important differences in glacier retreat, −27.6% for OAG vs. −5.1% for BG (2004–2014), together with a significantly higher impact of BC in OAG than BG. Regarding the sources of the measured BC, considering that both glaciers are at a similar distance from Santiago, it can be considered that there is another source influencing OAG, which could be the mountain mining activities, considering the small distance existing between this glacier and the mines.

Generating and Mapping Amazonian Urban Regions Using a Geospatial Approach

(1) background: Urban representations of the Amazon are urgently needed in order to better understand the complexity of urban processes in this area of the World. So far, limited work that represents Amazonian urban regions has been carried out. (2) methods: Our study area is the Ecuadorian Amazon. We performed a K-means algorithm using six urban indicators: Urban fractal dimension, number of paved streets, urban radiant intensity (luminosity), and distances to the closest new deforested areas, to oil pollution sources, and to mining pollution sources. We also carried out fieldwork to qualitatively validate our geospatial and statistical analyses. (3) results: We generated six Amazonian urban regions representing different urban configurations and processes of major cities, small cities, and emerging urban zones. The Amazonian urban regions generated represent the urban systems of the Ecuadorian Amazon at a general scale, and correspond to the urban realities at a local scale. (4) conclusions: An Amazonian urban region is understood as a set of urban zones that are dispersed and share common urban characteristics such a similar distance to oil pollution sources or similar urban radiant intensity. Our regionalization model represents the complexity of the Amazonian urban systems, and the applied methodology could be transferred to other Amazonian countries.

Thermal response of skin diseased tissue treated by plasmonic nanoantenna

The thermal distribution in the diseased tissue treated by different methods faces the problem of an uncontrollable defused heat. In the present article, we use a plasmonic bowtie nanoantenna working in the near infrared region to enhance the temperature confinement in the tissue. The Computer Simulation Technology Studio Suite package version 2019 was used to execute the design of both plasmonic nanoantenna and the tissue. Gold nanostructure and silicon carbide dioxide are the components the plasmonic nanoantenna in the bowtie shape. The results showed that the distance between the tumor tissue and the antenna is important to determine the intensity field where the maximum field is 5.9*107 V/m at a distance of 100 nm. The maximum specific absorption rate is 1.92*1011 W/kg at a similar distance which gives a higher temperature in the tissue of 580 Co. It is concluded that from the obtained results that the near infrared (1064 nm) resonance wavelength is recommended in the treatment of cancer cell by plasmonic bowtie nanoantenna because higher intensity field is generated. The closer distance to the nanoantenna gives higher temperature in the tissue while the temperature gradually decreases in the tissue till 400 nm where no valuable temperature was detected.

Do Not Let the Robot Get too Close: Investigating the Shape and Size of Shared Interaction Space for Two People in a Conversation

Robotic and other autonomous systems that need to operate in environments with people should respect social rules. One important aspect of this is personal space, which is the space surrounding a person. When two people are in a conversation, they position themselves such that a so-called shared interaction space is created in the middle of them. The aim of the current research was to experimentally investigate the shape and size of this shared interaction space in different formations. In three experiments, we had a robot approaching two people who were having a conversation from 5 different directions, and those people indicated what would be a comfortable distance for the robot to stop. We expected that people would take the personal space of their conversation partner into account when stopping the robot. Findings of the three studies mostly confirm this expectation. Apart from some exceptions, people tend to stop the robot at a similar distance from their conversation partner as from themselves. If these findings are applied in the behavior of robotic and other autonomous systems, people would be more likely to trust and later accept robots in their physical space, ultimately creating natural social interactions between humans and robots.

How biomechanics, path planning and sensing enable gliding flight in a natural environment

Gliding animals traverse cluttered aerial environments when performing ecologically relevant behaviours. However, it is unknown how gliders execute collision-free flight over varying distances to reach their intended target. We quantified complete glide trajectories amid obstacles in a naturally behaving population of gliding lizards inhabiting a rainforest reserve. In this cluttered habitat, the lizards used glide paths with fewer obstacles than alternatives of similar distance. Their takeoff direction oriented them away from obstacles in their path and they subsequently made mid-air turns with accelerations of up to 0.5 g to reorient towards the target tree. These manoeuvres agreed well with a vision-based steering model which maximized their bearing angle with the obstacle while minimizing it with the target tree. Nonetheless, negotiating obstacles reduced mid-glide shallowing rates, implying greater loss of altitude. Finally, the lizards initiated a pitch-up landing manoeuvre consistent with a visual trigger model, suggesting that the landing decision was based on the optical size and speed of the target. They subsequently followed a controlled-collision approach towards the target, ending with variable impact speeds. Overall, the visually guided path planning strategy that enabled collision-free gliding required continuous changes in the gliding kinematics such that the lizards never attained theoretically ideal steady-state glide dynamics.

Development of a Scale for Measuring the Learner Autonomy of Distance Education Students

The purpose of this study was to develop a valid and reliable psychometric scale to measure the perceived autonomy of postgraduate students in the Hellenic Open University and similar distance education environments. Two dimensions of autonomy, namely personal and educational, were revealed from the literature review and the preliminary study. For the evaluation of each dimension, two subscales were developed. Following two pilot studies, the initial item pool led to the development of a 25-items questionnaire, which was then administered to a sample of 239 postgraduate students. The exploratory factor analysis revealed two factors for the personal autonomy subscale, with 7 items in total, and two factors for the educational autonomy subscale, with 9 items in total. The Cronbach’s alpha coefficient ranged between. 623 and .717. A statistically significant gender difference was found only for the personal autonomy subscale and, more specifically, for the factor ‘managing difficulties’, where female respondents received a lower score than males.