145 research outputs found
Echolocation of Central Amazonian ‘whispering’ phyllostomid bats: call design and interspecific variation
Phyllostomids (New World leaf-nosed bats) are the ecologically most diverse bat family and have undergone the most extensive adaptive radiation of any mammalian family. However comprehensive, multi-species studies regarding phyllostomid echolocation are scarce in the literature despite abundant ecological research. In this study, we describe the call structure and interspecific variation in call design of 40 sympatric phyllostomid species from the Central Brazilian Amazon, focussing on general patterns within genera, subfamilies and between feeding guilds. All but one species utilized short, broadband FM calls consisting of multiple harmonics. As reported for other bat families, peak frequency was negatively correlated with body mass and forearm length. Twenty-five species alternated the harmonic of maximum energy, principally between the second and third harmonic. Based on PCA, we were unable to detect any significant differences in echolocation call parameters between genera, subfamilies or different feeding guilds, confirming that acoustic surveys cannot be used to reliably monitor these species. We present Ametrida centurio as an exception to this generalized phyllostomid structure, as it is unique in producing a mono-harmonic call. Finally, we discuss several hypotheses regarding the evolutionary pressures influencing phyllostomid call structure
The presence of anhedonia in individuals with subacute and chronic stroke: an exploratory cohort study
Background Anhedonia refers to the diminished capacity to experience pleasure. It has been described both as a symptom of depression and an enduring behavioral trait that contributes its development. Specifically, in stroke patients, anhedonia has been closely linked to depression, resulting in reduced sensitivity to everyday pleasures and intrinsic motivation to engage in rehabilitation programs and maintain a healthy active lifestyle. This condition may hinder patients' recovery, diminishing their autonomy, functioning, and quality of life.Objective We aimed to explore the prevalence and level of anhedonia and those variables that might be associated in patients with both ischemic and hemorrhagic stroke at subacute and chronic phases of the disease.Methods We conducted an exploratory cohort study with a sample of 125 patients with subacute and chronic stroke presenting upper-limb motor deficits. We measured participants' level of anhedonia with four items from the Beck Depression Inventory-II that describe the symptoms of this condition: loss of pleasure, loss of interest, loss of energy, and loss of interest in sex. We also collected demographic and clinical information and evaluated motor and cognitive functions as well as levels of depression, apathy, and various mood states. The results were compared to a sample of 71 healthy participants of similar age, sex, and level of education.Results Stroke patients demonstrated a significantly higher prevalence (18.5-19.7%) and level of anhedonia compared to the healthy controls (4.3%), regardless of stroke phase, level of motor impairment, and other clinical variables. Furthermore, post-stroke anhedonia was associated with lower levels of motivation and higher levels of negative mood states such as fatigue and anger in the long term. Importantly, anhedonia level was superior in stroke patients than in healthy controls while controlling for confounding effects of related emotional conditions.Conclusion This study provides novel evidence on the prevalence, level and factors related to anhedonia post-stroke. We emphasize the importance of assessing and treating anhedonia in this population, as well as conducting large-scale cohort and longitudinal studies to test its influence on long-term functional and emotional recovery
Feed, Microbiota, and Gut Immunity: Using the Zebrafish Model to Understand Fish Health
Aquafeed companies aim to provide solutions to the various challenges related to nutrition and health in aquaculture. Solutions to promote feed efficiency and growth, as well as improving the fish health or protect the fish gut from inflammation may include dietary additives such as prebiotics and probiotics. The general assumption is that feed additives can alter the fish microbiota which, in turn, interacts with the host immune system. However, the exact mechanisms by which feed influences host-microbe-immune interactions in fish still remain largely unexplored. Zebrafish rapidly have become a well-recognized animal model to study host-microbe-immune interactions because of the diverse set of research tools available for these small cyprinids. Genome editing technologies can create specific gene-deficient zebrafish that may contribute to our understanding of immune functions. Zebrafish larvae are optically transparent, which allows for in vivo imaging of specific (immune) cell populations in whole transgenic organisms. Germ-free individuals can be reared to study host-microbe interactions. Altogether, these unique zebrafish features may help shed light on the mechanisms by which feed influences host-microbe-immune interactions and ultimately fish health. In this review, we first describe the anatomy and function of the zebrafish gut: the main surface where feed influences host-microbe-immune interactions. Then, we further describe what is currently known about the molecular pathways that underlie this interaction in the zebrafish gut. Finally, we summarize and critically review most of the recent research on prebiotics and probiotics in relation to alterations of zebrafish microbiota and immune responses. We discuss the advantages and disadvantages of the zebrafish as an animal model for other fish species to study feed effects on host-microbe-immune interactions.</p
An active tectonic field for CO2 storage management: the Hontomín onshore case study (Spain)
One of the concerns of underground CO2 onshore
storage is the triggering of induced seismicity and fault reactivation by the pore pressure increasing. Hence, a comprehensive analysis of the tectonic parameters involved in the
storage rock formation is mandatory for safety management
operations. Unquestionably, active faults and seal faults depicting the storage bulk are relevant parameters to be considered. However, there is a lack of analysis of the active
tectonic strain field affecting these faults during the CO2
storage monitoring. The advantage of reconstructing the tectonic field is the possibility to determine the strain trajectories and describing the fault patterns affecting the reservoir
rock. In this work, we adapt a methodology of systematic
geostructural analysis to underground CO2 storage, based on
the calculation of the strain field from kinematics indicators
on the fault planes (ey and ex for the maximum and minimum horizontal shortening, respectively). This methodology
is based on a statistical analysis of individual strain tensor
solutions obtained from fresh outcrops from the Triassic to
the Miocene. Consequently, we have collected 447 fault data
in 32 field stations located within a 20 km radius. The understanding of the fault sets’ role for underground fluid circulation can also be established, helping further analysis of
CO2 leakage and seepage. We have applied this methodology
to Hontomín onshore CO2 storage facilities (central Spain).
The geology of the area and the number of high-quality outcrops made this site a good candidate for studying the strain
field from kinematics fault analysis. The results indicate a
strike-slip tectonic regime with maximum horizontal shortening with a 160 and 50◦ E trend for the local regime, which
activates NE–SW strike-slip faults. A regional extensional
tectonic field was also recognized with a N–S trend, which
activates N–S extensional faults, and NNE–SSW and NNW–
SSE strike-slip faults, measured in the Cretaceous limestone
on top of the Hontomín facilities. Monitoring these faults
within the reservoir is suggested in addition to the possibility of obtaining a focal mechanism solutions for microearthquakes (M < 3)This work has been partially supported by the European Project ENOS: ENabling Onshore CO2 Storage in Europe, H2020 Project ID: 653718 and the Spanish project 3GEO, CGL2017-83931-C3-2-P, MICIU-FEDE
Electrical cortical stimulation can impair production of the alphabet without impairing counting
Neurosurgery has the potential to cure patients with drug-resistant focal epilepsy, but carries the risk of permanent language impairment when surgery involves the dominant hemisphere of the brain. This risk can be estimated and minimized using electrical stimulation mapping (ESM), which uses cognitive and linguistic tasks during cortical ESM to differentiate "eloquent" and "resectable" areas in the brain. One such task, counting, is often used to screen and characterize language during ESM in patients whose language abilities are limited. Here we report a patient with drug-resistant epilepsy arising from the language-dominant hemisphere using fMRI. Our patient experienced loss of the ability to recite or write the alphabet, but not to count, during ESM of the dominant left posterior superior temporal gyrus. This selective impairment extended to both spoken and written production. We suggest the need for caution when using counting as a sole means to screen language function and as a method of testing low functioning patients using ESM
Nonlinear Quantum Photonics with a Tin-Vacancy Center Coupled to a One-Dimensional Diamond Waveguide
Color-centers integrated with nanophotonic devices have emerged as a
compelling platform for quantum science and technology. Here we integrate
tin-vacancy centers in a diamond waveguide and investigate the interaction with
light at the single-photon level. We observe single-emitter induced extinction
of the transmitted light up to 25% and measure the nonlinear effect on the
photon statistics. Furthermore, we demonstrate fully tunable interference
between the reflected single-photon field and laser light back-scattered at the
fiber end and show the corresponding controlled change between bunched and
anti-bunched photon statistics in the reflected field
Secondary forest buffers the effects of fragmentation on aerial insectivorous bat species following 30 years of passive forest restoration
Passive forest restoration can buffer the effects of habitat loss on biodiversity. We acoustically surveyed aerial insectivorous bats in a whole‐ecosystem fragmentation experiment in the Brazilian Amazon over a 2‐year period, across 33 sites, comprising continuous old‐growth forest, remnant fragments, and regenerating secondary forest matrix. We analyzed the activity of 10 species/sonotypes to investigate occupancy across habitat types and responses to fragment size and interior‐edge‐matrix (IEM) disturbance gradients. Employing a multiscale approach, we investigated guild (edge foragers, forest specialists, flexible forest foragers, and open space specialists) and species‐level responses to vegetation structure and forest cover, edge, and patch density across six spatial scales (0.5–3 km). We found species‐specific habitat occupancy patterns and nuanced responses to fragment size and the IEM disturbance gradient. For example, Furipterus horrens had lower activity in secondary forest sites and the interior and edge of the smallest fragments (1 and 10 ha) compared to continuous forest, and only two species (Pteronotus spp.) showed no habitat preference and no significant responses across the IEM and fragment size gradients. Only the Molossus sonotype responded negatively to vegetation structure. We uncovered no negative influence of forest cover or edge density at guild or species‐level. Our results indicate that reforestation can buffer the negative effects of fragmentation and although these effects can still be detected in some species, generally aerial insectivorous bats appear to be in recovery after 30 years of passive forest restoration. Our findings reinforce the need to protect regenerating forests while conserving vast expanses of old‐growth forest
Interactive handwriting recognition with limited user effort
The final publication is available at Springer via http://dx.doi.org/10.1007/s10032-013-0204-5[EN] Transcription of handwritten text in (old) documents is an important, time-consuming task for digital libraries. Although post-editing automatic recognition of handwritten text is feasible, it is not clearly better than simply ignoring it and transcribing the document from scratch. A more effective approach is to follow an interactive approach in which both the system is guided by the user, and the user is assisted by the system to complete the transcription task as efficiently as possible. Nevertheless, in some applications,
the user effort available to transcribe documents is limited and fully supervision of the system output is not realistic. To circumvent these problems, we propose a novel interactive approach which efficiently employs user effort to transcribe a document by improving three different aspects. Firstly, the system employs a limited amount of effort to solely supervise recognised words that are likely to be incorrect. Thus, user effort is efficiently focused on the supervision of words for which the system is not confident enough. Secondly, it refines the initial transcription provided to the user by recomputing it constrained to user supervisions. In this way, incorrect words in unsupervised parts can be automatically amended without user supervision. Finally, it improves the underlying system models by retraining the system from partially supervised transcriptions. In order to prove these statements, empirical results are presented on two real databases showing that the proposed approach can notably reduce user effort in the transcription of handwritten text in (old) documents.The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under Grant Agreement No 287755 (transLectures). Also supported by the Spanish Government (MICINN, MITyC, "Plan E", under Grants MIPRCV "Consolider Ingenio 2010", MITTRAL (TIN2009-14633-C03-01), erudito.com (TSI-020110-2009-439), iTrans2 (TIN2009-14511), and FPU (AP2007-02867), and the Generalitat Valenciana (Grants Prometeo/2009/014 and GV/2010/067).Serrano Martinez Santos, N.; Giménez Pastor, A.; Civera Saiz, J.; Sanchis Navarro, JA.; Juan Císcar, A. (2014). Interactive handwriting recognition with limited user effort. 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The CERN n_TOF facility: a unique tool for nuclear data measurement
The study of the resonant structures in neutron-nucleus cross-sections, and therefore of the compoundnucleus
reaction mechanism, requires spectroscopic measurements to determine with high accuracy the energy of
the neutron interacting with the material under study. To this purpose, the neutron time-of-flight facility n_TOF has
been operating since 2001 at CERN. Its characteristics, such as the high intensity instantaneous neutron flux, the
wide energy range from thermal to few GeV, and the very good energy resolution, are perfectly suited to perform highquality
measurements of neutron-induced reaction cross sections. The precise and accurate knowledge of these cross
sections plays a fundamental role in nuclear technologies, nuclear astrophysics and nuclear physics. Two different
measuring stations are available at the n_TOF facility, called EAR1 and EAR2, with different characteristics of intensity
of the neutron flux and energy resolution. These experimental areas, combined with advanced detection systems lead
to a great flexibility in performing challenging measurement of high precision and accuracy, and allow the investigation
isotopes with very low cross sections, or available only in small quantities, or with very high specific activity. The
characteristics and performances of the two experimental areas of the n_TOF facility will be presented, together with
the most important measurements performed to date and their physics case. In addition, the significant upcoming
measurements will be introduced.Postprint (published version
External validation of the PAGE-B score for HCC risk prediction in people living with HIV/HBV coinfection.
BACKGROUND & AIMS
Hepatitis B virus (HBV) coinfection is common among people living with HIV (PLWH) and the most important cause of hepatocellular carcinoma (HCC). Whereas risk prediction tools for HCC exist for patients with HBV monoinfection, they have not been evaluated in PLWH. We performed an external validation of PAGE-B in people with HIV/HBV coinfection.
METHODS
We included PLWH with a positive HBsAg and without HCC before starting tenofovir from four European cohorts, and estimated the predictive performance of PAGE-B on HCC occurrence over 15 years of tenofovir-containing antiretroviral therapy (ART). Model discrimination was assessed after multiple imputation using Cox regression with the prognostic index as covariate, and by calculating Harrell's c-index. Calibration was assessed by comparing cumulative incidences with the PAGE-B derivation study using Kaplan-Meier curves.
RESULTS
In total, 2'963 individuals with HIV/HBV coinfection on tenofovir-containing ART were included. PAGE-B was <10 in 26.5%, 10-17 in 57.7%, and ≥18 in 15.7% of patients. Within a median follow-up of 9.6 years, HCC occurred in 68 individuals (2.58/1000 patient-years, 95% confidence interval [CI] 2.03-3.27). The regression slope of the prognostic index for developing HCC within 15 years was 0.93 (95% CI 0.61-1.25), and the pooled c-index was 0.77 (range 0.73-0.80), both indicating good model discrimination. Cumulative incidence of HCC was lower in our study compared to the derivation study. A PAGE-B cut-off of <10 had a negative predictive value for developing HCC within 5 years of 99.4%. Restricting efforts to individuals with a PAGE-B of ≥10 would spare HCC screening in 27% of individuals.
CONCLUSIONS
For individuals with HIV/HBV coinfection, PAGE-B is a valid tool to determine the need for HCC screening.
IMPACT AND IMPLICATIONS
Chronic hepatitis B virus (HBV) infection is the most important cause of hepatocellular carcinoma (HCC) among people living with HIV, and valid risk prediction may guide HCC screening efforts to high-risk individuals. We aimed at validating PAGE-B, a risk prediction tool that is based on age, gender, and platelets, among 2963 individuals with HIV/HBV coinfection who received tenofovir-containing antiretroviral therapy. In the present study, PAGE-B showed good discrimination, adequate calibration, and a cut-off of less than 10 had a negative predictive value for developing HCC within 5 years of 99.4%. These results indicate that PAGE-B is a simple and valid risk prediction tool to determine the need for HCC screening among people living with HIV and HBV
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