A 3-component laser-Doppler velocimeter data acquisition and reduction system

A laser doppler velocimeter capable of measuring all three components of velocity simultaneously in low-speed flows is described. All the mean velocities, Reynolds stresses, and higher-order products can be evaluated. The approach followed is to split one of the two colors used in a 2-D system, thus creating a third set of beams which is then focused in the flow from an off-axis direction. The third velocity component is computed from the known geometry of the system. The laser optical hardware and the data acquisition electronics are described in detail. In addition, full operating procedures and listings of the software (written in BASIC and ASSEMBLY languages) are also included. Some typical measurements obtained with this system in a vortex/mixing layer interaction are presented and compared directly to those obtained with a cross-wire system

Geographic variation in dispersal distance facilitates range expansion of a lake shore plant in response to climate change

AimGeographic variation in dispersal abilities is widespread and likely to affect species’ range dynamics in response to climate change. However, distribution models that predict climate‐induced range shifts do not account for spatial variation in dispersal. We developed an eco‐genetic model to investigate how variation in dispersal distances across a species’ range could interact with climate‐induced selection and alter predicted range dynamics in a species with documented variation in dispersal traits.LocationWe investigated the range of an annual plant, Cakile edentula var. lacustris, which occupies beaches spanning a 555 km latitudinal gradient along the Laurentian Great Lakes.MethodsWe built a hybrid model that combines climatic niche modelling, based on decadal climate projections, with an individual‐based model that allows for evolutionary processes to act upon a heritable dispersal kernel. We evaluated how spatial variation in dispersal distance and dispersal evolution influenced range dynamics, spatial and temporal variation in dispersal, and the distribution of neutral genetic variation. The model was parametrized with data on C. edentula’s distribution, life history and dispersal characteristics.ResultsGeographic variation in dispersal distance, adaptive dispersal evolution and dispersal distance increased the potential for local populations of C. edentula to keep pace with changing climatic conditions through range shifts. Dispersal distances always increased at the expanding and contracting range edges when dispersal was allowed to evolve. Furthermore, scenarios where dispersal distances were initially lower at the range edges resulted in the largest evolutionary changes over 105 years (>1.5 km increase in mean distance at northern edge). Adaptive dispersal evolution always reduced neutral genetic diversity across the species’ range.Main conclusionsVariation in dispersal abilities across C. edentula’s range and adaptive evolution led to different predicted outcomes in range dynamics during climate change illustrating the importance of including spatial variation in dispersal into species distribution models.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151269/1/ddi12951.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151269/2/ddi12951_am.pd

Negotiating daughterhood and strangerhood: retrospective accounts of serial migration

Most considerations of daughtering and mothering take for granted that the subjectivities of mothers and daughters are negotiated in contexts of physical proximity throughout daughters’ childhoods. Yet many mothers and daughters spend periods separated from each other, sometimes across national borders. Globally, an increasing number of children experience life in transnational families. This paper examines the retrospective narratives of four women who were serial migrants as children (whose parents migrated before they did) . It focuses on their accounts of the reunion with their mothers and how these fit with the ways in which they construct their mother-daughter relationships. We take a psychosocial approach by using a psychoanalytically-informed reading of these narratives to acknowledge the complexities of the attachments produced in the context of migration and to attend to the multi-layered psychodynamics of the resulting relationships. The paper argues that serial migration positioned many of the daughters in a conflictual emotional landscape from which they had to negotiate ‘strangerhood’ in the context of sadness at leaving people to whom they were attached in order to join their mothers (or parents). As a result, many were resistant to being positioned as daughters, doing daughtering and being mothered in their new homes

Frontiers in data analytics for adaptation research: Topic modeling

Rapid growth over the past two decades in digitized textual information represents untapped potential for methodological innovations in the adaptation governance literature that draw on machine learning approaches already being applied in other areas of computational social sciences. This Focus Article explores the potential for text mining techniques, specifically topic modeling, to leverage this data for large‐scale analysis of the content of adaptation policy documents. We provide an overview of the assumptions and procedures that underlie the use of topic modeling, and discuss key areas in the adaptation governance literature where topic modeling could provide valuable insights. We demonstrate the diversity of potential applications for topic modeling with two examples that examine: (a) how adaptation is being talked about by political leaders in United Nations Framework Convention on Climate Change; and (b) how adaptation is being discussed by decision‐makers and public administrators in Canadian municipalities using documents collected from 25 city council archives. This article is categorized under: Vulnerability and Adaptation to Climate Change > Institutions for Adaptatio

Validation of Coupled Atmosphere-Fire Behavior Models

Recent advances in numerical modeling and computer power have made it feasible to simulate the dynamical interaction and feedback between the heat and turbulence induced by wildfires and the local atmospheric wind and temperature fields. At Los Alamos National Laboratory, the authors have developed a modeling system that includes this interaction by coupling a high resolution atmospheric dynamics model, HIGRAD, with a fire behavior model, BEHAVE, to predict the spread of wildfires. The HIGRAD/BEHAVE model is run at very high resolution to properly resolve the fire/atmosphere interaction. At present, these coupled wildfire model simulations are computationally intensive. The additional complexity of these models require sophisticated methods for assuring their reliability in real world applications. With this in mind, a substantial part of the research effort is directed at model validation. Several instrumented prescribed fires have been conducted with multi-agency support and participation from chaparral, marsh, and scrub environments in coastal areas of Florida and inland California. In this paper, the authors first describe the data required to initialize the components of the wildfire modeling system. Then they present results from one of the Florida fires, and discuss a strategy for further testing and improvement of coupled weather/wildfire models

Experimental field studies of Asian ape social systems

The Asian apes, orangutans and gibbons, possess unusual social systems among anthropoid primates. Social groups of gibbons consist of mated adult pairs and their offspring; mature orangutans are primarily solitary. Recent experimental field research has begun to yield insights into the behavioral mechanisms employed by these animals to maintain their characteristic patterns of social dispersion. While spatial separation between female orangutans appears to be maintained passively, aggression, which is manifest during direct encounters and long-distance vocal interactions, mediates male asociality. Male-male aggression is the result of intense intrasexual competition occurring between animals for mating access to females. To reduce intrasexual competition, male orangutans have adopted alternative mating tactics. In contrast to female orangutans, female gibbons show marked agonistic tendencies toward conspecifics. Female territoriality contributes to preventing males from becoming polygynous. Male gibbons, restricted to monogamous relationships, attempt to ensure their paternity through intrasexual aggression. These observations suggest that the spatial dispersion of females constrains male mating options in both species. However, variations between orangutan and gibbon social systems can be understood as consequences of the temporal dispersion of sexually receptive females. The temporal clumping of females, due to relatively high operational sex ratios, limits the ability of male gibbons to acquire multiple mates. Conversely, an extremely low operational sex ratio in orangutans creates a strong selection pressure for intrasexual competition and polygamous mating. These considerations provide a novel framework for interpreting the social systems of the African apes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44557/1/10764_2005_Article_BF02192784.pd

Monoubiquitination of syntaxin 3 leads to retrieval from the basolateral plasma membrane and facilitates cargo recruitment to exosomes

Syntaxin 3 (Stx3), a SNARE protein located and functioning at the apical plasma membrane of epithelial cells, is required for epithelial polarity. A fraction of Stx3 is localized to late endosomes/lysosomes, although how it traffics there and its function in these organelles is unknown. Here we report that Stx3 undergoes monoubiquitination in a conserved polybasic domain. Stx3 present at the basolateral—but not the apical—plasma membrane is rapidly endocytosed, targeted to endosomes, internalized into intraluminal vesicles (ILVs), and excreted in exosomes. A nonubiquitinatable mutant of Stx3 (Stx3-5R) fails to enter this pathway and leads to the inability of the apical exosomal cargo protein GPRC5B to enter the ILV/exosomal pathway. This suggests that ubiquitination of Stx3 leads to removal from the basolateral membrane to achieve apical polarity, that Stx3 plays a role in the recruitment of cargo to exosomes, and that the Stx3-5R mutant acts as a dominant-negative inhibitor. Human cytomegalovirus (HCMV) acquires its membrane in an intracellular compartment and we show that Stx3-5R strongly reduces the number of excreted infectious viral particles. Altogether these results suggest that Stx3 functions in the transport of specific proteins to apical exosomes and that HCMV exploits this pathway for virion excretion

Canine respiratory coronavirus employs caveolin-1-mediated pathway for internalization to HRT-18G cells

Canine respiratory coronavirus (CRCoV), identified in 2003, is a member of the Coronaviridae family. The virus is a betacoronavirus and a close relative of human coronavirus OC43 and bovine coronavirus. Here, we examined entry of CRCoV into human rectal tumor cells (HRT-18G cell line) by analyzing co-localization of single virus particles with cellular markers in the presence or absence of chemical inhibitors of pathways potentially involved in virus entry. We also targeted these pathways using siRNA. The results show that the virus hijacks caveolin-dependent endocytosis to enter cells via endocytic internalization