40 research outputs found
Haptic Feedback Relocation from the Fingertips to the Wrist for Two-Finger Manipulation in Virtual Reality
Relocation of haptic feedback from the fingertips to the wrist has been
considered as a way to enable haptic interaction with mixed reality virtual
environments while leaving the fingers free for other tasks. We present a pair
of wrist-worn tactile haptic devices and a virtual environment to study how
various mappings between fingers and tactors affect task performance. The
haptic feedback rendered to the wrist reflects the interaction forces occurring
between a virtual object and virtual avatars controlled by the index finger and
thumb. We performed a user study comparing four different finger-to-tactor
haptic feedback mappings and one no-feedback condition as a control. We
evaluated users' ability to perform a simple pick-and-place task via the
metrics of task completion time, path length of the fingers and virtual cube,
and magnitudes of normal and shear forces at the fingertips. We found that
multiple mappings were effective, and there was a greater impact when visual
cues were limited. We discuss the limitations of our approach and describe next
steps toward multi-degree-of-freedom haptic rendering for wrist-worn devices to
improve task performance in virtual environments.Comment: 6 pages, 9 figures, 1 table, submitted and accepted to the IEEE/RSJ
International Conference on Intelligent Robots and Systems (IROS) 2022
Conferenc
The impact of mass-transfer physics on the observable properties of field binary black hole populations
We study the impact of mass-transfer physics on the observable properties of
binary black hole populations formed through isolated binary evolution. We
investigate the impact of mass-accretion efficiency onto compact objects and
common-envelope efficiency on the observed distributions of ,
and . We find that low common envelope efficiency translates to
tighter orbits post common envelope and therefore more tidally spun up
second-born black holes. However, these systems have short merger timescales
and are only marginally detectable by current gravitational-waves detectors as
they form and merge at high redshifts (), outside current detector
horizons. Assuming Eddington-limited accretion efficiency and that the
first-born black hole is formed with a negligible spin, we find that all
non-zero systems in the detectable population can come only from
the common envelope channel as the stable mass-transfer channel cannot shrink
the orbits enough for efficient tidal spin-up to take place. We find the local
rate density () for the common envelope channel is in the range
considering a range of while for the stable mass transfer channel the rate density is . The latter drops by two orders of magnitude if the mass
accretion onto the black hole is not Eddington limited because conservative
mass transfer does not shrink the orbit as efficiently as non-conservative mass
transfer does. Finally, using GWTC-2 events, we constrain the lower bound of
branching fraction from other formation channels in the detected population to
be . Assuming all remaining events to be formed through either stable
mass transfer or common envelope channels, we find moderate to strong evidence
in favour of models with inefficient common envelopes.Comment: 26 pages, 13 figures, accepted for publication in A&
POSYDON: A General-Purpose Population Synthesis Code with Detailed Binary-Evolution Simulations
Most massive stars are members of a binary or a higher-order stellar systems,
where the presence of a binary companion can decisively alter their evolution
via binary interactions. Interacting binaries are also important astrophysical
laboratories for the study of compact objects. Binary population synthesis
studies have been used extensively over the last two decades to interpret
observations of compact-object binaries and to decipher the physical processes
that lead to their formation. Here, we present POSYDON, a novel, binary
population synthesis code that incorporates full stellar-structure and
binary-evolution modeling, using the MESA code, throughout the whole evolution
of the binaries. The use of POSYDON enables the self-consistent treatment of
physical processes in stellar and binary evolution, including: realistic
mass-transfer calculations and assessment of stability, internal
angular-momentum transport and tides, stellar core sizes, mass-transfer rates
and orbital periods. This paper describes the detailed methodology and
implementation of POSYDON, including the assumed physics of stellar- and
binary-evolution, the extensive grids of detailed single- and binary-star
models, the post-processing, classification and interpolation methods we
developed for use with the grids, and the treatment of evolutionary phases that
are not based on pre-calculated grids. The first version of POSYDON targets
binaries with massive primary stars (potential progenitors of neutron stars or
black holes) at solar metallicity.Comment: 60 pages, 33 figures, 8 tables, referee's comments addressed. The
code and the accompanying documentations and data products are available at
https:\\posydon.or
Pre-exenterative chemotherapy, a novel therapeutic approach for patients with persistent or recurrent cervical cancer
BACKGROUND: Most cervical cancer patients with pelvic recurrent or persistent disease are not candidates for exenteration, therefore, they only receive palliative chemotherapy. Here we report the results of a novel treatment modality for these patients pre-exenterative chemotherapy- under the rational that the shrinking of the pelvic tumor would allow its resection. METHODS: Patients with recurrent or persistent disease and no evidence of systemic disease, considered not be candidates for pelvic exenteration because of the extent of pelvic tumor, received 3-courses of platinum-based chemotherapy. Response was evaluated by CT scan and bimanual pelvic examination; however the decision to perform exenteration relied on the physical findings. Toxicity to chemotherapy was evaluated with standard criteria. Survival was analyzed with the Kaplan-Meier method. RESULTS: Seventeen patients were studied. The median number of chemotherapy courses was 4. There were 9 patients who responded to chemotherapy, evaluated by bimanual examination and underwent pelvic exenteration. Four of them had pathological complete response. Eight patients did not respond and were not subjected to surgery. One patient died due to exenteration complications. At a median follow-up of 11 months, the median survival for the whole group was 11 months, 3 months in the non-operated and 32 months in those subjected to exenteration. CONCLUSION: Pre-exenterative chemotherapy is an alternative for cervical cancer patients that are no candidates for exenteration because of the extent of the pelvic disease. Its place in the management of recurrent disease needs to be investigated in randomized studies, however, its value for offering long-term survival in some of these patients with no other option than palliative care must be stressed
TRY plant trait database – enhanced coverage and open access
Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
Finishing the euchromatic sequence of the human genome
The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
Relatório de estágio em farmácia comunitária
Relatório de estágio realizado no âmbito do Mestrado Integrado em Ciências Farmacêuticas, apresentado à Faculdade de Farmácia da Universidade de Coimbr
The Role of Core-collapse Physics in the Observability of Black Hole Neutron Star Mergers as Multimessenger Sources
Recent detailed 1D core-collapse simulations have brought new insights on the
final fate of massive stars, which are in contrast to commonly used parametric
prescriptions. In this work, we explore the implications of these results to
the formation of coalescing black-hole (BH) - neutron-star (NS) binaries, such
as the candidate event GW190426_152155 reported in GWTC-2. Furthermore, we
investigate the effects of natal kicks and the NS's radius on the synthesis of
such systems and potential electromagnetic counterparts linked to them.
Synthetic models based on detailed core-collapse simulations result in an
increased merger detection rate of BH-NS systems ( yr), 5 to
10 times larger than the predictions of "standard" parametric prescriptions.
This is primarily due to the formation of low-mass BH via direct collapse, and
hence no natal kicks, favored by the detailed simulations. The fraction of
observed systems that will produce an electromagnetic counterpart, with the
detailed supernova engine, ranges from -%, depending on uncertainties in
the NS equation of state. Notably, in most merging systems with electromagnetic
counterparts, the NS is the first-born compact object, as long as the NS's
radius is . Furthermore, core-collapse models that
predict the formation of low-mass BHs with negligible natal kicks increase the
detection rate of GW190426_152155-like events to yr; with
an associated probability of electromagnetic counterpart % for all
supernova engines. However, increasing the production of direct-collapse
low-mass BHs also increases the synthesis of binary BHs, over-predicting their
measured local merger density rate. In all cases, models based on detailed
core-collapse simulation predict a ratio of BH-NSs to binary BHs merger rate
density that is at least twice as high as other prescriptions.Comment: 13 pages, 5 figures, 3 table
Applying RE-AIM to examine the impact of an implementation facilitation package to scale up a program for Veterans with chronic obstructive pulmonary disease
Abstract Background US Veterans are four times more likely to be diagnosed with chronic obstructive pulmonary disease (COPD) compared to the civilian population with no care model that consistently improves Veteran outcomes when scaled. COPD Coordinated Access to Reduce Exacerbations (CARE) is a care bundle intended to improve the delivery of evidence-based practices to Veterans. To address challenges to scaling this program in the Veterans’ Health Administration (VA), the COPD CARE Academy (Academy), an implementation facilitation package comprised of five implementation strategies was designed and implemented. Methods This evaluation utilized a mixed-methods approach to assess the impact of the Academy’s implementation strategies on the RE-AIM framework implementation outcomes and the extent to which they were effective at increasing clinicians’ perceived capability to implement COPD CARE. A survey was administered one week after Academy participation and a semi-structured interview conducted 8 to 12 months later. Descriptive statistics were calculated for quantitative items and thematic analysis was used to analyze open-ended items. Results Thirty-six clinicians from 13 VA medical centers (VAMCs) participated in the Academy in 2020 and 2021 and 264 front-line clinicians completed COPD CARE training. Adoption of the Academy was indicated by high rates of Academy session attendance (90%) and high utilization of Academy resources. Clinicians reported the Academy to be acceptable and appropriate as an implementation package and clinicians from 92% of VAMCs reported long-term utilization of Academy resources. Effectiveness of the Academy was represented by clinicians’ significant increases (p < 0.05) in their capability to complete ten implementation tasks after Academy participation. Conclusions This evaluation found that the use of implementation facilitation paired with additional strategies enhanced the capacity of clinicians to implement COPD CARE. Future assessments are needed to explore post-academy resources that would help VAMCs to strategize localized approaches to overcome barriers