656 research outputs found
Leptogenesis in Supersymmetric Economical 3-3-1 Model
We study a leptogenesis scenario in which the heavy Majorana neutrinos are produced non-thermally in inflaton decays in the supersymmetric economical model with inflationary scenario. The lepton-number violating interactions among the inflaton and right-handed neutrinos appear at the one-loop level, and this is a reason for non-thermal leptogenesis scenario. The bound followed from the gravitino abundance and the cosmological constraint on neutrino mass/the neutrino oscillation data is: eV. By taking the reheating temperature as low as GeV, we get a limit on the ratio of masses of the light heavies neutrino to those of the inflaton to be:
Flat Seeking Bayesian Neural Networks
Bayesian Neural Networks (BNNs) provide a probabilistic interpretation for
deep learning models by imposing a prior distribution over model parameters and
inferring a posterior distribution based on observed data. The model sampled
from the posterior distribution can be used for providing ensemble predictions
and quantifying prediction uncertainty. It is well-known that deep learning
models with lower sharpness have better generalization ability. However,
existing posterior inferences are not aware of sharpness/flatness in terms of
formulation, possibly leading to high sharpness for the models sampled from
them. In this paper, we develop theories, the Bayesian setting, and the
variational inference approach for the sharpness-aware posterior. Specifically,
the models sampled from our sharpness-aware posterior, and the optimal
approximate posterior estimating this sharpness-aware posterior, have better
flatness, hence possibly possessing higher generalization ability. We conduct
experiments by leveraging the sharpness-aware posterior with state-of-the-art
Bayesian Neural Networks, showing that the flat-seeking counterparts outperform
their baselines in all metrics of interest.Comment: Accepted at NeurIPS 202
Investigation of Sodium Manganese Oxide Nanowires Synthesized by Hydrothermal Method for Alkaline Ion Battery
Sodium Manganese Oxide (NaxMnO2) has attracted much attention as cathode materials for alkaline ion battery due to the ability of fast charge and discharge ion Na+, in particular in nanoscale. We report on the synthesis of NaxMnO2 nanowires via hydrothermal synthesis route from Mn2O3 and NaOH solution. The morphological observation indicates that the obtained Na0.44MnO2 nanowires with diameters of about 20-30 nm, length up to several micrometers were formed by this process. The electrochemical properties of fabricated materials were investigated by means of cyclic voltammetry technique and show that Sodium Manganese Oxide (NaxMnO2) is a promising material in the field of research and fabrication alkaline ion battery
Revealing the excitation energy transfer network of Light-Harvesting Complex II by a phenomenological analysis of two-dimensional electronic spectra at 77 K
Energy equilibration in light-harvesting antenna systems normally occurs before energy is transferred to a reaction center. The equilibration mechanism is a characteristic of the excitation energy transfer (EET) network of the antenna. Characterizing this network is crucial in understanding the first step of photosynthesis. We present our phenomenology-based analysis procedure and results in obtaining the excitonic energy levels, spectral linewidths, and transfer-rate matrix of Light-Harvesting Complex II directly from its 2D electronic spectra recorded at 77 K with waiting times between 100 fs to 100 ps. Due to the restriction of the models and complexity of the system, a unique EET network cannot be constructed. Nevertheless, a recurring pattern of energy transfer with very similar overall time scales between spectral components (excitons) is consistently obtained. The models identify a "bottleneck" state in the 664-668 nm region although with a relatively shorter lifetime (similar to 4-6 ps) of this state compared to previous studies. The model also determines three terminal exciton states at 675, 677-678, and 680-681 nm that are weakly coupled to each other. The excitation energy equilibration between the three termini is found to be independent of the initial excitation conditions, which is a crucial design for the light-harvesting complexes to ensure the energy flow under different light conditions and avoid excitation trapping. We proposed two EET schemes with tentative pigment assignments based on the interpretation of the modeling results together with previous structure-based calculations and spectroscopic observables. Published under license by AIP Publishing
An Exciton Dynamics Model of Bryopsis corticulans Light-Harvesting Complex II
Bryopsis corticulans is a marine green macroalga adapted to the intertidal environment. It possesses siphonaxanthin-binding light-harvesting complexes of photosystem II (LHCII) with spectroscopic properties markedly different from the LHCII in plants. By applying a phenomenological fitting procedure to the two-dimensional electronic spectra of the LHCII from B. corticulans measured at 77 K, we can extract information about the excitonic states and energy-transfer processes. The fitting method results in well-converged parameters, including excitonic energy levels with their respective transition dipole moments, spectral widths, energy-transfer rates, and coupling properties. The 2D spectra simulated from the fitted parameters concur very well with the experimental data, showing the robustness of the fitting method. An excitonic energy-transfer scheme can be constructed from the fitting parameters. It shows the rapid energy transfer from chlorophylls (Chls) b to a at subpicosecond time scales and a long-lived state in the Chl b region at around 659 nm. Three weakly connected terminal states are resolved at 671, 675, and 677 nm. The lowest state is higher in energy than that in plant LHCII, which is probably because of the fewer number of Chls a in a B. corticulans LHCII monomer. Modeling based on existing Hamiltonians for the plant LHCII structure with two Chls a switched to Chls b suggests several possible Chl a-b replacements in comparison with those of plant LHCII. The adaptive changes result in a slower energy equilibration in the complex, revealed by the longer relaxation times of several exciton states compared to those of plant LHCII. The strength of our phenomenological fitting method for obtaining excitonic energy levels and energy-transfer network is put to the test in systems such as B. corticulans LHCII, where prior knowledge on exact assignment and spatial locations of pigments are lacking
TextANIMAR: Text-based 3D Animal Fine-Grained Retrieval
3D object retrieval is an important yet challenging task, which has drawn
more and more attention in recent years. While existing approaches have made
strides in addressing this issue, they are often limited to restricted settings
such as image and sketch queries, which are often unfriendly interactions for
common users. In order to overcome these limitations, this paper presents a
novel SHREC challenge track focusing on text-based fine-grained retrieval of 3D
animal models. Unlike previous SHREC challenge tracks, the proposed task is
considerably more challenging, requiring participants to develop innovative
approaches to tackle the problem of text-based retrieval. Despite the increased
difficulty, we believe that this task has the potential to drive useful
applications in practice and facilitate more intuitive interactions with 3D
objects. Five groups participated in our competition, submitting a total of 114
runs. While the results obtained in our competition are satisfactory, we note
that the challenges presented by this task are far from being fully solved. As
such, we provide insights into potential areas for future research and
improvements. We believe that we can help push the boundaries of 3D object
retrieval and facilitate more user-friendly interactions via vision-language
technologies.Comment: arXiv admin note: text overlap with arXiv:2304.0573
Spatiotemporal evolution of SARS-CoV-2 Alpha and Delta variants during large nationwide outbreak of COVID-19, Vietnam, 2021
We analyzed 1,303 SARS-CoV-2 whole-genome sequences from Vietnam, and found the Alpha and Delta variants were responsible for a large nationwide outbreak of COVID-19 in 2021. The Delta variant was confined to the AY.57 lineage and caused >1.7 million infections and >32,000 deaths. Viral transmission was strongly affected by nonpharmaceutical interventions
Point-of-care C-reactive protein testing to reduce inappropriate use of antibiotics for non-severe acute respiratory infections in Vietnamese primary health care: a randomised controlled trial
Background Inappropriate antibiotic use for acute respiratory tract infections is common in primary health care, but
distinguishing serious from self-limiting infections is diffi cult, particularly in low-resource settings. We assessed
whether C-reactive protein point-of-care testing can safely reduce antibiotic use in patients with non-severe acute
respiratory tract infections in Vietnam.
Method We did a multicentre open-label randomised controlled trial in ten primary health-care centres in northern
Vietnam. Patients aged 1–65 years with at least one focal and one systemic symptom of acute respiratory tract infection
were assigned 1:1 to receive either C-reactive protein point-of-care testing or routine care, following which antibiotic
prescribing decisions were made. Patients with severe acute respiratory tract infection were excluded. Enrolled
patients were reassessed on day 3, 4, or 5, and on day 14 a structured telephone interview was done blind to the
intervention. Randomised assignments were concealed from prescribers and patients but not masked as the test
result was used to assist treatment decisions. The primary outcome was antibiotic use within 14 days of follow-up. All
analyses were prespecifi ed in the protocol and the statistical analysis plan. All analyses were done on the intention-totreat
population and the analysis of the primary endpoint was repeated in the per-protocol population. This trial is
registered under number NCT01918579.
Findings Between March 17, 2014, and July 3, 2015, 2037 patients (1028 children and 1009 adults) were enrolled and
randomised. One adult patient withdrew immediately after randomisation. 1017 patients were assigned to receive
C-reactive protein point-of-care testing, and 1019 patients were assigned to receive routine care. 115 patients in the
C-reactive protein point-of-care group and 72 patients in the routine care group were excluded in the intention-to-treat
analysis due to missing primary endpoint. The number of patients who used antibiotics within 14 days was 581 (64%)
of 902 patients in the C-reactive protein group versus 738 (78%) of 947 patients in the control group (odds ratio
[OR] 0·49, 95% CI 0·40–0·61; p<0·0001). Highly signifi cant diff erences were seen in both children and adults, with
substantial heterogeneity of the intervention eff ect across the 10 sites (I²=84%, 95% CI 66–96). 140 patients in the
C-reactive protein group and 137 patients in the routine care group missed the urine test on day 3, 4, or 5. Antibiotic
activity in urine on day 3, 4, or 5 was found in 267 (30%) of 877 patients in the C-reactive protein group versus
314 (36%) of 882 patients in the routine treatment group (OR 0·78, 95% CI 0·63–0·95; p=0·015). Time to resolution
of symptoms was similar in both groups. Adverse events were rare, with no deaths and a total of 14 hospital admissions
(six in the C-reactive protein group and eight in the control group).
Interpretation C-reactive protein point-of-care testing reduced antibiotic use for non-severe acute respiratory tract
infection without compromising patients’ recovery in primary health care in Vietnam. Health-care providers might
have become familiar with the clinical picture of low C-reactive protein, leading to reduction in antibiotic prescribing
in both groups, but this would have led to a reduction in observed eff ect, rather than overestimation. Qualitative
analysis is needed to address diff erences in context in order to implement this strategy to improve rational antibiotic
use for patients with acute respiratory infection in low-income and middle-income countries
A Bibliometric Analysis of the Global Research Trend in Child Maltreatment
Child maltreatment remains a major health threat globally that requires the understanding of socioeconomic and cultural contexts to craft effective interventions. However, little is known about research agendas globally and the development of knowledge-producing networks in this field of study. This study aims to explore the bibliometric overview on child maltreatment publications to understand their growth from 1916 to 2018. Data from the Web of Science Core Collection were collected in May 2018. Only research articles and reviews written in the English language were included, with no restrictions by publication date. We analyzed publication years, number of papers, journals, authors, keywords and countries, and presented the countries collaboration and co-occurrence keywords analysis. From 1916 to 2018, 47, 090 papers (53.0% in 2010–2018) were published in 9442 journals. Child Abuse & Neglect (2576 papers; 5.5%); Children and Youth Services Review (1130 papers; 2.4%) and Pediatrics (793 papers, 1.7%) published the most papers. The most common research areas were Psychology (16, 049 papers, 34.1%), Family Studies (8225 papers, 17.5%), and Social Work (7367 papers, 15.6%). Among 192 countries with research publications, the most prolific countries were the United States (26, 367 papers), England (4676 papers), Canada (3282 papers) and Australia (2664 papers). We identified 17 authors who had more than 60 scientific items. The most cited papers (with at least 600 citations) were published in 29 journals, headed by the Journal of the American Medical Association (JAMA) (7 papers) and the Lancet (5 papers). This overview of global research in child maltreatment indicated an increasing trend in this topic, with the world’s leading centers located in the Western countries led by the United States. We called for interdisciplinary research approaches to evaluating and intervening on child maltreatment, with a focus on low-middle income countries (LMICs) settings and specific contexts
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