Showing papers by "Hampshire College published in 2021"
TL;DR: In this paper, a brief update on the advances available for laser-induced breakdown spectroscopy (LIBS) is provided, focusing broad experimental and instrumental possibiliti...
Abstract: The purpose of this tutorial article is to provide a brief update on the advances available for laser-induced breakdown spectroscopy (LIBS), focusing broad experimental and instrumental possibiliti...
36 citations
TL;DR: The translational invasion ecology (TIE) as mentioned in this paper is an approach that embodies an intentional and inclusive process in which researchers, stakeholders, and decision makers collaborate to develop and implement ecological research via joint consideration of the ecological, sociological, economic, and/or political contexts in order to improve invasive species management.
Abstract: Effective natural resource management and policy is contingent on information generated by research. Conversely, the applicability of research depends on whether it is responsive to the needs and constraints of resource managers and policy makers. However, many scientific fields including invasion ecology suffer from a disconnect between research and practice. Despite strong socio-political imperatives, evidenced by extensive funding dedicated to addressing invasive species, the pairing of invasion ecology with stakeholder needs to support effective management and policy is lacking. As a potential solution, we propose translational invasion ecology (TIE). As an extension of translational ecology, as a framework to increase collaboration among scientists, practitioners, and policy makers to reduce negative impacts of invasive species. As an extension of translational ecology, TIE is an approach that embodies an intentional and inclusive process in which researchers, stakeholders, and decision makers collaborate to develop and implement ecological research via joint consideration of the ecological, sociological, economic, and/or political contexts in order to improve invasive species management. TIE ideally results in improved outcomes as well as shared benefits between researchers and managers. We delineate the steps of our proposed TIE approach and describe successful examples of ongoing TIE projects from the US and internationally. We suggest practical ways to begin incorporating TIE into research and management practices, including supporting boundary-spanning organizations and activities, expanding networks, sharing translational experiences, and measuring outcomes. We find that there is a need for strengthened boundary spanning, as well as funding and recognition for advancing translational approaches. As climate change and globalization exacerbate invasive species impacts, TIE provides a promising approach to generate actionable ecological research while improving outcomes of invasive species management and policy decisions.
12 citations
TL;DR: The ability to produce outer membrane projections in the form of tubular membrane extensions (MEs) and membrane vesicles (MVs) is a widespread phenomenon among diderm bacteria as mentioned in this paper.
Abstract: The ability to produce outer membrane projections in the form of tubular membrane extensions (MEs) and membrane vesicles (MVs) is a widespread phenomenon among diderm bacteria. Despite this, our knowledge of the ultrastructure of these extensions and their associated protein complexes remains limited. Here, we surveyed the ultrastructure and formation of MEs and MVs, and their associated protein complexes, in tens of thousands of electron cryo-tomograms of ~90 bacterial species that we have collected for various projects over the past 15 years (Jensen lab database), in addition to data generated in the Briegel lab. We identified outer MEs and MVs in 13 diderm bacterial species and classified several major ultrastructures: (1) tubes with a uniform diameter (with or without an internal scaffold), (2) tubes with irregular diameter, (3) tubes with a vesicular dilation at their tip, (4) pearling tubes, (5) connected chains of vesicles (with or without neck-like connectors), (6) budding vesicles and nanopods. We also identified several protein complexes associated with these MEs and MVs which were distributed either randomly or exclusively at the tip. These complexes include a secretin-like structure and a novel crown-shaped structure observed primarily in vesicles from lysed cells. In total, this work helps to characterize the diversity of bacterial membrane projections and lays the groundwork for future research in this field.
11 citations
TL;DR: The proposed calibration methods for LIBS and micro-XRF were tested for the 40 PCB subsamples, in which the best results were obtained combining both data sources though a low-level data fusion.
11 citations
TL;DR: The ancient populations were chronically affected by boron overexposure, suggesting that ancient geogenic water contamination should be considered when discussing the biocultural trajectories of ancient populations.
Abstract: OBJECTIVES This study explores whether ancient Atacama Desert populations in northern Chile were exposed to endemic boron contamination. MATERIALS AND METHODS Using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS), we studied 144 strands of ancient mummy hair, ranging from 3000 B.C. to 1500 A.D., excavated from the Lluta, Azapa, and Camarones valleys in northern Chile. We tested whether these ancient populations showed signs of significant boron concentration in hair tissue. RESULTS On average, all individuals from these valleys showed high boron concentrations, ranging from 1.5 to 4 times above the average boron concentration in contemporary hair (baseline <0.85 μg/g). The boron concentration in mummy hair varied according to the main geographic areas mentioned above. CONCLUSIONS The rivers of northern Chile have high geogenic boron concentrations. They contain 38 times above the recommended limit for human consumption. Geogenic boron contamination likely played a role in population morbidity and the types of crops that were cultivated in antiquity. The ancient populations were chronically affected by boron overexposure, suggesting that ancient geogenic water contamination should be considered when discussing the biocultural trajectories of ancient populations.
7 citations
TL;DR: In this article, the authors examined the use of burrows by a common intertidal crab, Minuca pugnax, to control body temperature and found that an increase in 1°C in the surface temperature led to a 0.71°C increase in body temperature for females and an increase of 0.34-0.77°C for males.
Abstract: Behavioral thermoregulation is an important defense against the negative impacts of climate change for ectotherms. In this study we examined the use of burrows by a common intertidal crab, Minuca pugnax, to control body temperature. To understand how body temperatures respond to changes in the surface temperature and explore how efficiently crabs exploit the cooling potential of burrows to thermoregulate, we measured body, surface, and burrow temperatures during low tide on Sapelo Island, GA in March, May, August, and September of 2019. We found that an increase in 1°C in the surface temperature led to a 0.70-0.71°C increase in body temperature for females and an increase in 0.75-0.77°C in body temperature for males. Body temperatures of small females were 0.3°C warmer than large females for the same surface temperature. Female crabs used burrows more efficiently for thermoregulation compared to the males. Specifically, an increase of 1°C in the cooling capacity (the difference between the burrow temperature and the surface temperature) led to an increase of 0.42-0.50°C for females and 0.34-0.35°C for males in the thermoregulation capacity (the difference between body temperature and surface temperature). The body temperature that crabs began to use burrows to thermoregulate was estimated to be around 24°C, which is far below the critical body temperatures that could lead to death. Many crabs experience body temperatures of 24°C early in the reproductive season, several months before the hottest days of the year. Because the use of burrows involves fitness trade-offs, these results suggest that warming temperatures could begin to impact crabs far earlier in the year than expected.
6 citations
TL;DR: In this article, the shape of the apical region of lily pollen tube changes rhythmically as the growth rate of the tube oscillates becoming alternately more prolate then back to oblate.
Abstract: The shape of the apical region of lily pollen tube changes rhythmically as the growth rate of the tube oscillates becoming alternately more prolate then back to oblate. We quantified shape change by calculating the curvature of the cross-sectional edge of the pollen tube tip and cross-correlating curvature changes with growth rate. The apical region takes the form of a partial elliptical spheroid, with variation in the length and location of the minor axis. During oscillation curvature profiles show a sharp increase in curvature at the “shoulders” of the apex when oblate, 4–7 μm from the flatter central zone. As the tip becomes more prolate, the “shoulders” decrease rapidly in curvature and move towards the growth axis as curvature at the tip increases. We understand curvature changes to represent differential changes in local wall expansion rates, driven by uniform turgor pressure and mediated by changes in wall polysaccharides. To become more oblate, the tip region must become less extensible than the “shoulder” region. And, as the tip becomes more prolate, the increased curvature must be due to increased local expansion. We found that changes in the growth velocity of the “shoulders” of the cell measured as the progress of the cell edge along the growth axis are cyclically out of phase with growth velocity at the tip such that the shoulder regions lag for part of the oscillation cycle, then “catch up” as the growth rate at the tip reaches a maximum and begins to decline. In this way the cell becomes oblate. Cell shape and growth rate oscillate in concert and are functionally related. Spatial change in edge growth rate points to important cellular locations for further investigation of vesicle movement and exocytosis, calcium gradients, and actin dynamics in lily pollen tubes.
5 citations
TL;DR: The Son of Saul as mentioned in this paper is a Hungarian film that immerses its viewers in the life of a member of the Sonderkommando at Auschwitz-Birkenau.
Abstract: The essay analyzes the movie Son of Saul, a Hungarian film that immerses its viewers in the life of a member of the Sonderkommando at Auschwitz-Birkenau. It is not an easy film to watch as it prese...
5 citations
TL;DR: Past pollution episodes and the intensity of mining activity in a contaminated region can be unraveled, using archived elemental information in tree rings, using laser ablation-inductively coupled plasma-mass spectrometry to make a timeline of metal(loid)s uptake in trees.
4 citations
TL;DR: The results provide additional support to prior behavioral and neural visual search findings that spatial WM availability, whether as an ability of the participant's processing system or based on task demands, plays an important role in efficient visual search.
Abstract: The lateralized ERP N2pc component has been shown to be an effective marker of attentional object selection when elicited in a visual search task, specifically reflecting the selection of a target item among distractors (Eimer, Kiss, & Nicholas, 2011). Moreover, when targets are known in advance, the visual search process is guided by representations of target features held in working memory at the time of search, thus guiding attention to objects with target-matching features (Grubert & Eimer, 2016). Previous studies have shown that manipulating working memory availability via concurrent tasks or within task manipulations influences visual search performance and the N2pc. Other studies have indicated that visual (non-spatial) versus spatial working memory manipulations have differential contributions to visual search. To investigate whether visual and spatial working memory availability contribute differentially to visual search, we assess participants’ visual and spatial working memory ability independent of the visual search task to determine whether such individual differences in working memory availability affect task performance and the N2pc. Participants (n=205) completed a visual search task to elicit the N2pc and separate visual working memory (VWM) and spatial working memory (SPWM) assessments. Greater SPWM, but not VWM, ability is correlated with and predicts higher visual search accuracy and greater N2pc amplitudes. Neither VWM nor SPWM was related to N2pc latency. These results provide additional support to prior behavioral and neural visual search findings that spatial WM availability, whether as an ability of the participant’s processing system or based on task demands, plays an important role in efficient visual search.
4 citations
TL;DR: The authors discuss how feasibility and acceptability of obtaining biological samples for research purposes from marginalized communities demands careful social and ethical consideration, and discuss the feasibility and acceptance of such samples for marginalized communities.
Abstract: Obtaining biological samples for research purposes from members of marginalized communities demands careful social and ethical consideration. This paper aims to discuss how feasibility and acceptab...
TL;DR: Weak evidence for competitive exclusion is found on two congeneric Antbirds that occur in sympatry across a habitat matrix in Colombia, and the degree to which one species can competitively exclude another may vary, especially across a dynamic landscape.
Abstract:
Interspecific aggression may shape species distributions through competitive exclusion, resulting in spatial segregation, or facilitate sympatry as an adaptive mechanism for resource partitioning. Competitive exclusion results from asymmetric aggression of one species towards another, but if the aggressive relationship between species is symmetric, they may persist in sympatry. Interspecific aggression is widely cited as a mechanism for maintaining the distributional limits of tropical birds, but how it shapes the spatial dynamics of competing species that are sympatric over larger geographic areas is less clear. To address this issue, we conducted reciprocal playback experiments on two congeneric Antbirds — Thamnophilus atrinucha and T. doliatus — that occur in sympatry across a habitat matrix in Colombia to characterize their relationship as symmetrically or asymmetrically aggressive and analyzed point count data to assess the degree to which they occur sympatrically. We found weak evidence for competitive exclusion, with the larger T. doliatus responding asymmetrically to T. atrinucha, and the two species having a low co-detection rate during point counts. However, despite their 22% difference in body size, T. atrinucha still responded to T. doliatus playback in over half of our trials, and the two species co-occurred on nearly 25% of point counts, indicating that interspecific aggression does not drive complete spatial segregation. Our findings highlight how the degree to which one species can competitively exclude another may vary, especially across a dynamic landscape.
TL;DR: This work surveyed the ultrastructure and formation of MEs and MVs, and their associated protein complexes, in tens of thousands of electron cryo-tomograms of ∼ 90 bacterial species that were collected for various projects over the past 15 years (Jensen lab database), in addition to data generated in the Briegel lab.
Abstract: The ability to produce membrane projections in the form of tubular membrane extensions (MEs) and membrane vesicles (MVs) is a widespread phenomenon among bacteria. Despite this, our knowledge of the ultrastructure of these extensions and their associated protein complexes remains limited. Here, we surveyed the ultrastructure and formation of MEs and MVs, and their associated protein complexes, in tens of thousands of electron cryo-tomograms of ∼ 90 bacterial species that we have collected for various projects over the past 15 years (Jensen lab database), in addition to data generated in the Briegel lab. We identified MEs and MVs in 13 species and classified several major ultrastructures: 1) tubes with a uniform diameter (with or without an internal scaffold), 2) tubes with irregular diameter, 3) tubes with a vesicular dilation at their tip, 4) pearling tubes, 5) connected chains of vesicles (with or without neck-like connectors), 6) budding vesicles and nanopods. We also identified several protein complexes associated with these MEs and MVs which were distributed either randomly or exclusively at the tip. These complexes include a secretin-like structure and a novel crown-shaped structure observed primarily in vesicles from lysed cells. In total, this work helps to characterize the diversity of bacterial membrane projections and lays the groundwork for future research in this field.
TL;DR: In this paper, the authors describe a novel, ubiquitous and evolutionarily widespread hat-shaped structure embedded in the inner membrane of bacteria, of yet-unidentified function, that is related to the flagellar type III secretion system (fT3SS).
Abstract: The flagellar type III secretion system (fT3SS) is a suite of membrane-embedded and cytoplasmic proteins responsible for building the bacterial flagellar motility machinery. Homologous proteins form the injectisome machinery bacteria use to deliver effector proteins into eukaryotic cells, and other family members have recently been reported to be involved in the formation of membrane nanotubes. Here we describe a novel, ubiquitous and evolutionarily widespread hat-shaped structure embedded in the inner membrane of bacteria, of yet-unidentified function, that is related to the fT3SS, adding to the already rich repertoire of this family of nanomachines.