317 research outputs found
Carry-over effects of bumblebee associative learning in changing plant communities leads to increased costs of foraging
Flower visitors learn to avoid food-deceptive plants and to prefer rewarding ones by associating floral cues to rewards. As co-occurring plant species have different phenologies, cue-reward associations vary over time. It is not known how these variations affect flower visitors' foraging costs and learning. We trained bumblebees of two colonies to forage in a community of deceptive and rewarding artificial inflorescences whose flower colours were either similar or dissimilar. We then modified the community composition by turning the rewarding inflorescences into unrewarding and adding rewarding inflorescences of a novel flower colour. In the short term, bees trained to similar rather than dissimilar inflorescences experienced higher costs of foraging (decreased foraging speed and accuracy) in the novel community. The colonies differed in their speed-accuracy trade-off. In the longer term, bees adapted their foraging behaviour to the novel community composition by increasingly visiting the novel rewarding inflorescence
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Tethyan magnetostratigraphy from Pizzo Mondello (Sicily) and correlation to the Late Triassic Newark astrochronological polarity time scale
We present the magnetostratigraphy and stable isotope stratigraphy from an expanded (∼430-m-thick) Upper Triassic marine limestone section at Pizzo Mondello, Sicily, and review published biostratigraphic information that can be used to define the location of the conodont Carnian-Norian and Norian-Rhaetian boundaries in this section. Pizzo Mondello offers good potential for magneto-stratigraphic correlation of marine biostratigraphic and chemostratigraphic data with the continental Newark astrochronological polarity time scale (APTS) for development of an integrated Late Triassic time scale. The relatively stable average values of δ18O centered on 0‰ are a strong indication that the Cherty Limestone at Pizzo Mondello suffered very little diagenetic overprinting. The conodont Carnian-Norian boundary is located 12.5 m above a positive shift of δ13C. A statistical approach was applied to evaluate various Pizzo Mondello to Newark magnetostratigraphic correlations. Two correlation options have the highest correlation coefficients. In option #1, the base of Pizzo Mondello correlates with the middle part of the Newark APTS, whereas in option #2, the base of Pizzo Mondello starts toward the early part of the Newark APTS. We prefer option #2 in which the Carnian-Norian boundary based on conodonts, as well as its closely associated positive δ13C shift, correspond to Newark magnetozone E7 at ca. 228–227 Ma (adopting Newark astrochronology), implying a long Norian with a duration of ∼20 m.y., and a Rhaetian of ∼6 m.y. duration. These ages are in fact not inconsistent with the few high-quality radiometric dates that are available for Late Triassic time scale calibration. Based on its good exposure, accessibility, stratigraphic thickness and continuity, and multiple chronostratigraphic correlation possibilities, we propose Pizzo Mondello as global stratigraphic section and point for the base of the Norian
Tethyan magnetostratigraphy from Pizzo Mondello (Sicily) and correlation to the Late Triassic Newark astrochronological polarity time scale
We present the magnetostratigraphy and stable isotope stratigraphy from an expanded (∼430-m-thick) Upper Triassic marine limestone section at Pizzo Mondello, Sicily, and review published biostratigraphic information that can be used to define the location of the conodont Carnian-Norian and Norian-Rhaetian boundaries in this section. Pizzo Mondello offers good potential for magneto-stratigraphic correlation of marine biostratigraphic and chemostratigraphic data with the continental Newark astrochronological polarity time scale (APTS) for development of an integrated Late Triassic time scale. The relatively stable average values of δ18O centered on 0‰ are a strong indication that the Cherty Limestone at Pizzo Mondello suffered very little diagenetic overprinting. The conodont Carnian-Norian boundary is located 12.5 m above a positive shift of δ13C. A statistical approach was applied to evaluate various Pizzo Mondello to Newark magnetostratigraphic correlations. Two correlation options have the highest correlation coefficients. In option #1, the base of Pizzo Mondello correlates with the middle part of the Newark APTS, whereas in option #2, the base of Pizzo Mondello starts toward the early part of the Newark APTS. We prefer option #2 in which the Carnian-Norian boundary based on conodonts, as well as its closely associated positive δ13C shift, correspond to Newark magnetozone E7 at ca. 228–227 Ma (adopting Newark astrochronology), implying a long Norian with a duration of ∼20 m.y., and a Rhaetian of ∼6 m.y. duration. These ages are in fact not inconsistent with the few high-quality radiometric dates that are available for Late Triassic time scale calibration. Based on its good exposure, accessibility, stratigraphic thickness and continuity, and multiple chronostratigraphic correlation possibilities, we propose Pizzo Mondello as global stratigraphic section and point for the base of the Norian
Transhistorical Urban Landscape as Hypermap
This article explores the conception, design, and implementation of a hypertextual map that we call hypermap. Using Giovanni Nolli’s 1748 map of the city of Rome as a backbone, we conducted an experiment based on one of the routes defined by Giuseppe Vasi’s Grand Tour of Rome to collect various types of urban and environmental information, thus aiming to connect a multiplicity of data from different nature and times periods to enhance the serendipitous elaboration of new narratives, interpretations, and data (namely "unfolding") not implicitly enacted by the pure analytical and mechanistic overlapping of gathered data ("folding"). This experiment is part of the research project entitled Datathink that was conducted at the Bibliotheca Hertziana - Max Planck Institute for Art History in Rome, the experiment serves as a proof of concept for an augmented database of the urban landscape in the city of Rome and new ways to facilitate the access and enhancement of cultural artifacts and knowledge
Evaluation of Clinical and Immunological Markers for predicting Virological Failure in a HIV/AIDS treatment cohort in Busia, Kenya
In resource-limited settings where viral load (VL) monitoring is scarce or unavailable, clinicians must use immunological and clinical criteria to define HIV virological treatment failure. This study examined the performance of World Health Organization (WHO) clinical and immunological failure criteria in predicting virological failure in HIV patients receiving antiretroviral therapy (ART)
Probing ISM Structure in Trumpler 14 & Carina I Using The Stratospheric Terahertz Observatory 2
We present observations of the Trumpler 14/Carina I region carried out using
the Stratospheric Terahertz Observatory 2 (STO2). The Trumpler 14/Carina I
region is in the west part of the Carina Nebula Complex, which is one of the
most extreme star-forming regions in the Milky Way. We observed Trumpler
14/Carina I in the 158 m transition of [C\,{\sc ii}] with a spatial
resolution of 48 and a velocity resolution of 0.17 km s. The
observations cover a 0.25 by 0.28 area with central position
{\it l} = 297.34, {\it b} = -0.60. The kinematics show that
bright [C\,{\sc ii}] structures are spatially and spectrally correlated with
the surfaces of CO clouds, tracing the photodissociation region and ionization
front of each molecular cloud. Along 7 lines of sight that traverse Tr 14 into
the dark ridge to the southwest, we find that the [C\,{\sc ii}] luminosity from
the HII region is 3.7 times that from the PDR. In same los we find in the PDRs
an average ratio of 1:4.1:5.6 for the mass in atomic gas:dark-CO gas: molecular
gas traced by CO. Comparing multiple gas tracers including HI 21cm, [C\,{\sc
ii}], CO, and radio recombination lines, we find that the HII regions of the
Carina Nebula Complex are well-described as HII regions with one-side freely
expanding towards us, consistent with the champagne model of ionized gas
evolution. The dispersal of the GMC in this region is dominated by EUV
photoevaporation; the dispersal timescale is 20-30 Myr.Comment: ApJ accepte
Spectral Topography of the Subthalamic Nucleus to Inform Next-Generation Deep Brain Stimulation.
BACKGROUND
The landscape of neurophysiological symptoms and behavioral biomarkers in basal ganglia signals for movement disorders is expanding. The clinical translation of sensing-based deep brain stimulation (DBS) also requires a thorough understanding of the anatomical organization of spectral biomarkers within the subthalamic nucleus (STN).
OBJECTIVES
The aims were to systematically investigate the spectral topography, including a wide range of sub-bands in STN local field potentials (LFP) of Parkinson's disease (PD) patients, and to evaluate its predictive performance for clinical response to DBS.
METHODS
STN-LFPs were recorded from 70 PD patients (130 hemispheres) awake and at rest using multicontact DBS electrodes. A comprehensive spatial characterization, including hot spot localization and focality estimation, was performed for multiple sub-bands (delta, theta, alpha, low-beta, high-beta, low-gamma, high-gamma, and fast-gamma (FG) as well as low- and fast high-frequency oscillations [HFO]) and compared to the clinical hot spot for rigidity response to DBS. A spectral biomarker map was established and used to predict the clinical response to DBS.
RESULTS
The STN shows a heterogeneous topographic distribution of different spectral biomarkers, with the strongest segregation in the inferior-superior axis. Relative to the superiorly localized beta hot spot, HFOs (FG, slow HFO) were localized up to 2 mm more inferiorly. Beta oscillations are spatially more spread compared to other sub-bands. Both the spatial proximity of contacts to the beta hot spot and the distance to higher-frequency hot spots were predictive for the best rigidity response to DBS.
CONCLUSIONS
The spatial segregation and properties of spectral biomarkers within the DBS target structure can additionally be informative for the implementation of next-generation sensing-based DBS. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society
Clumped isotope evidence for episodic, rapid flow of fluids in a mineralized fault system in the Peak District, UK
We have used clumped isotope thermometry to study a fault-hosted hydrothermal calcite vein associated with the Mississippi Valley Type (MVT) mineralization on the Derbyshire Platform in the southern Pennines, UK. This is the first published dataset obtained using a new mass spectrometer, MIRA, optimized for clumped isotope analysis and an associated clumped isotope-temperature calibration. We analysed multiple generations of vein growth at high spatial resolution in two transects across the vein. The vein grew episodically at temperatures between 40 and 100°C. We interpret each episode of growth as being associated with an increasing flux of formation waters from deep sedimentary basins next to the mineralized platform and an accompanying increase in the precipitation temperatures. Heat is conserved in the fluid as it ascends along the fault surface and, thus, flow must have been fast and restricted to short-lived pulses. The flux could have been driven by high pore pressures associated with rapid sedimentation, hydrocarbon generation and diagenesis in the basinal facies of the Visean Bowland-Hodder group. Natural hydraulic fracturing of shale units and failure of capillary seals, possibly triggered by uplift, allowed the release of fluids into aquifers within the sediment pile. The transmission of high pore fluid pressures from the shales to the fault zone, aided by the compressibility of the gas phase in two-phase pore fluids, may have resulted in fault rupture, accompanied by enhanced fracture permeability and rapid fluid flow. Vein growth ceased as pore pressures dissipated. Such behaviour is closely related to a seismic valve type model for mineralization
Genetic diversity from proviral DNA as a proxy for time since HIV-1 infection
HIV-1 RNA genetic diversity predicts time since infection which is important for clinical care and research. It's unclear, however, whether proviral DNA genetic diversity sampled under suppressive antiretroviral therapy can be used for this purpose. We tested whether proviral genetic diversity from NGS sequences predicts time since infection and recency in 221 people with HIV-1 with known infection time. Proviral diversity was significantly associated with time since infection (p<5*10-07, R2 up to 25%) and predictive of treatment initiation during recent infection (AUC-ROC up to 0.85). This shows the utility of proviral genetic diversity as a proxy for time since infection
Genetic diversity from proviral DNA as a proxy for time since HIV-1 infection.
HIV-1 RNA genetic diversity predicts time since infection which is important for clinical care and research. It's unclear, however, whether proviral DNA genetic diversity sampled under suppressive antiretroviral therapy can be used for this purpose. We tested whether proviral genetic diversity from NGS sequences predicts time since infection and recency in 221 people with HIV-1 with known infection time. Proviral diversity was significantly associated with time since infection (p<5*10-07, R2 up to 25%) and predictive of treatment initiation during recent infection (AUC-ROC up to 0.85). This shows the utility of proviral genetic diversity as a proxy for time since infection
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