152 research outputs found
Generation mechanism of a new type of unburnt gas pocket and its influences on the detonation-wave/boundary-layer interaction
Fast Hybrid Cascade for Voxel-based 3D Object Classification
Voxel-based 3D object classification has been frequently studied in recent
years. The previous methods often directly convert the classic 2D convolution
into a 3D form applied to an object with binary voxel representation. In this
paper, we investigate the reason why binary voxel representation is not very
suitable for 3D convolution and how to simultaneously improve the performance
both in accuracy and speed. We show that by giving each voxel a signed distance
value, the accuracy will gain about 30% promotion compared with binary voxel
representation using a two-layer fully connected network. We then propose a
fast fully connected and convolution hybrid cascade network for voxel-based 3D
object classification. This threestage cascade network can divide 3D models
into three categories: easy, moderate and hard. Consequently, the mean
inference time (0.3ms) can speedup about 5x and 2x compared with the
state-of-the-art point cloud and voxel based methods respectively, while
achieving the highest accuracy in the latter category of methods (92%).
Experiments with ModelNet andMNIST verify the performance of the proposed
hybrid cascade network
Catch Me If You Can: A New Low-Rate DDoS Attack Strategy Disguised by Feint
While collaborative systems provide convenience to our lives, they also face
many security threats. One of them is the Low-rate Distributed
Denial-of-Service (LDDoS) attack, which is a worthy concern. Unlike volumetric
DDoS attacks that continuously send large volumes of traffic, LDDoS attacks are
more stealthy and difficult to be detected owing to their low-volume feature.
Due to its stealthiness and harmfulness, LDDoS has become one of the most
destructive attacks in cloud computing. Although a few LDDoS attack detection
and defense methods have been proposed, we observe that sophisticated LDDoS
attacks (being more stealthy) can bypass some of the existing LDDoS defense
methods. To verify our security observation, we proposed a new Feint-based
LDDoS (F-LDDoS) attack strategy. In this strategy, we divide a Pulse Interval
into a Feinting Interval and an Attack Interval. Unlike the previous LDDoS
attacks, the bots also send traffic randomly in the Feinting Interval, thus
disguise themselves as benign users during the F-LDDoS attack. In this way,
although the victim detects that it is under an LDDoS attack, it is difficult
to locate the attack sources and apply mitigation solutions. Experimental
results show that F-LDDoS attack can degrade TCP bandwidth 6.7%-14% more than
the baseline LDDoS attack. Besides, F-LDDoS also reduces the similarities
between bot traffic and aggregated attack traffic, and increases the
uncertainty of packet arrival. These results mean that the proposed F-LDDoS is
more effective and more stealthy than normal LDDoS attacks. Finally, we discuss
the countermeasures of F-LDDoS to draw the attention of defenders and improve
the defense methods
Astrocytes deficient in circadian clock gene Bmal1 show enhanced activation responses to amyloid-beta pathology without changing plaque burden
An emerging link between circadian clock function and neurodegeneration has indicated a critical role for the molecular clock in brain health. We previously reported that deletion of the core circadian clock gene Bmal1 abrogates clock function and induces cell-autonomous astrocyte activation. Regulation of astrocyte activation has important implications for protein aggregation, inflammation, and neuronal survival in neurodegenerative conditions such as Alzheimer\u27s disease (AD). Here, we investigated how astrocyte activation induced by Bmal1 deletion regulates astrocyte gene expression, amyloid-beta (Aβ) plaque-associated activation, and plaque deposition. To address these questions, we crossed astrocyte-specific Bmal1 knockout mice (Aldh1l1-Cr
Motivated to Gain: Awareness of an Impending Ending and the Ending Effect
The ending effect describes the phenomenon that individuals are more risk-taking during the final round of a series of risky decision tasks. Previous research suggests that the ending effect might be caused by a motivational shift induced by changes in time perception. However, none of the existing research directly tested the motivational state immediately before the last round of a series of risky decision tasks. To fill in this gap of knowledge, the present study tested whether this motivational shift indeed occurs immediately before the last round. All participants worked on 11 rounds of risky decision tasks, half of them knew that the decision tasks included 11 rounds, whereas the other half did not know. Before the last round of the risky decision tasks, all participants completed a visual reaction time task. It was found that, compared with participants who were not aware of the impending ending, those who knew they were approaching the last round responded to peripherally located character strings appearing immediately after gain-related words slower than those appearing after loss-related words, suggesting that perceived endings lead participants to be more motivated toward gaining rewards. This work provides critical evidence which supports the motivational account of the ending effect proposed in previous research. Such a finding would represent a next step in unpacking the psychological consequences of perceived endings in everyday life
Associations between socioeconomic status, obesity, cognition, and white matter microstructure in children
IMPORTANCE: Lower neighborhood and household socioeconomic status (SES) are associated with negative health outcomes and altered brain structure in children. It is unclear whether such findings extend to white matter and via what mechanisms.
OBJECTIVE: To assess whether and how neighborhood and household SES are independently associated with children\u27s white matter microstructure and examine whether obesity and cognitive performance (reflecting environmental cognitive and sensory stimulation) are plausible mediators.
DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used baseline data from participants in the Adolescent Brain Cognitive Development (ABCD) study. Data were collected at 21 US sites, and school-based recruitment was used to represent the US population. Children aged 9 to 11 years and their parents or caregivers completed assessments between October 1, 2016, and October 31, 2018. After exclusions, 8842 of 11 875 children in the ABCD study were included in the analyses. Data analysis was conducted from July 11 to December 19, 2022.
EXPOSURES: Neighborhood disadvantage was derived from area deprivation indices at participants\u27 primary residence. Household SES factors were total income and highest parental educational attainment.
MAIN OUTCOMES AND MEASURES: A restriction spectrum imaging (RSI) model was used to quantify restricted normalized directional (RND; reflecting oriented myelin organization) and restricted normalized isotropic (RNI; reflecting glial and neuronal cell bodies) diffusion in 31 major white matter tracts. The RSI measurements were scanner harmonized. Obesity was assessed through body mass index (BMI; calculated as weight in kilograms divided by height in meters squared), age- and sex-adjusted BMI z scores, and waist circumference, and cognition was assessed through the National Institutes of Health Toolbox Cognition Battery. Analyses were adjusted for age, sex, pubertal development stage, intracranial volume, mean head motion, and twin or siblingship.
RESULTS: Among 8842 children, 4543 (51.4%) were boys, and the mean (SD) age was 9.9 (0.7) years. Linear mixed-effects models revealed that greater neighborhood disadvantage was associated with lower RSI-RND in the left superior longitudinal fasciculus (β = -0.055; 95% CI, -0.081 to -0.028) and forceps major (β = -0.040; 95% CI, -0.067 to -0.013). Lower parental educational attainment was associated with lower RSI-RND in the bilateral superior longitudinal fasciculus (eg, right hemisphere: β = 0.053; 95% CI, 0.025-0.080) and bilateral corticospinal or pyramidal tract (eg, right hemisphere: β = 0.042; 95% CI, 0.015-0.069). Structural equation models revealed that lower cognitive performance (eg, lower total cognition score and higher neighborhood disadvantage: β = -0.012; 95% CI, -0.016 to -0.009) and greater obesity (eg, higher BMI and higher neighborhood disadvantage: β = -0.004; 95% CI, -0.006 to -0.001) partially accounted for the associations between SES and RSI-RND. Lower household income was associated with higher RSI-RNI in most tracts (eg, right inferior longitudinal fasciculus: β = -0.042 [95% CI, -0.073 to -0.012]; right anterior thalamic radiations: β = -0.045 [95% CI, -0.075 to -0.014]), and greater neighborhood disadvantage had similar associations in primarily frontolimbic tracts (eg, right fornix: β = 0.046 [95% CI, 0.019-0.074]; right anterior thalamic radiations: β = 0.045 [95% CI, 0.018-0.072]). Lower parental educational attainment was associated with higher RSI-RNI in the forceps major (β = -0.048; 95% CI, -0.077 to -0.020). Greater obesity partially accounted for these SES associations with RSI-RNI (eg, higher BMI and higher neighborhood disadvantage: β = 0.015; 95% CI, 0.011-0.020). Findings were robust in sensitivity analyses and were corroborated using diffusion tensor imaging.
CONCLUSIONS AND RELEVANCE: In this cross-sectional study, both neighborhood and household contexts were associated with white matter development in children, and findings suggested that obesity and cognitive performance were possible mediators in these associations. Future research on children\u27s brain health may benefit from considering these factors from multiple socioeconomic perspectives
Dynamic Budget Throttling in Repeated Second-Price Auctions
Throttling is one of the most popular budget control methods in today's
online advertising markets. When a budget-constrained advertiser employs
throttling, she can choose whether or not to participate in an auction after
the advertising platform recommends a bid. This paper focuses on the dynamic
budget throttling process in repeated second-price auctions from a theoretical
view. An essential feature of the underlying problem is that the advertiser
does not know the distribution of the highest competing bid upon entering the
market. To model the difficulty of eliminating such uncertainty, we consider
two different information structures. The advertiser could obtain the highest
competing bid in each round with full-information feedback. Meanwhile, with
partial information feedback, the advertiser could only have access to the
highest competing bid in the auctions she participates in. We propose the
OGD-CB algorithm, which involves simultaneous distribution learning and revenue
optimization. In both settings, we demonstrate that this algorithm guarantees
an regret with probability relative to the
fluid adaptive throttling benchmark. By proving a lower bound of
on the minimal regret for even the hindsight optimum, we
establish the near optimality of our algorithm. Finally, we compare the fluid
optimum of throttling to that of pacing, another widely adopted budget control
method. The numerical relationship of these benchmarks sheds new light on the
understanding of different online algorithms for revenue maximization under
budget constraints.Comment: 29 pages, 1 tabl
Newborn Screening and Molecular Profile of Congenital Hypothyroidism in a Chinese Population
To review the characteristics of newborn screening of congenital hypothyroidism (CH), we reviewed the newborn screening data, including the levels of blood spot thyroid-stimulating hormone (TSH), and serum TSH and free thyroxine (FT4), of all newborn infants who accepted the newborn screening program during the last 14 years. In total, 437,342 newborn infants underwent CH screening and 192 infants were diagnosed with CH and the incidence of CH was 1:2278. The positive rate of the initial screening was 0.96%, and the positive predictive value was 4.8%. We also designed a target sequencing panel including 13 causative genes: DUOX2, TG, TPO, TSHR, TTF1, TTF2, PAX8, NKX2-5, GNAS, THRA, TSHB, IYD and SLC5A5, to identify the spectrum and prevalence of disease-causing gene mutations in Chinese CH patients. CH-causing genes were detected by targeted next-generation sequencing in 106 CH infants. A total of 132 mutations were identified in 69 cases (65.1%). Of these 132 mutations, 92 (69.70%), 28 (21.21%), and 12 (9.09%) were related to thyroid dyshormonogenesis, thyroid dysgenesis, and thyrotropin resistance, respectively. Mutations in CH-causing genes were found mainly in DUOX2, TG and TSHR, and DUOX2 is the most gene mutation in Chinese CH patients
Concomitant valve surgery is associated with worse outcomes in surgical treatments of post-infarction ventricular aneurysm
ObjectiveTo evaluate the impact of concomitant valve surgery on the prognosis of patients who experienced coronary artery bypass graft (CABG) with/without ventricular reconstruction for the ventricular aneurysm.MethodsIn our department, 354 patients underwent CABG with/without ventricular reconstruction for a ventricular aneurysm from July 23rd, 2000 to December 23rd, 2022. A total of 77 patients received concomitant valve surgery, 37 of whom underwent replacement, and 40 of whom underwent repair. The baseline characteristics, prognostic, and follow-up information were statically analyzed. Univariate and multivariate Cox regression analyses were applied to identify the risk factors of long-term outcomes.ResultsCompared with patients who did not undergo valvular surgery, patients who experienced concomitant valve surgical treatments had a significantly lower survival rate (p = 0.00022) and a longer total mechanical ventilation time. Subgroup analysis indicated that the options of repair or replacement exhibited no statistically significant difference in postoperative mortality (p = 0.44) and prognosis. The multivariate Cox regression analysis suggested that the pre-operative cholesterol level (HR = 1.68), postoperative IABP (HR = 6.29), NYHA level (HR = 2.84), and pre-operative triglyceride level (HR = 1.09) were independent and significant predictors for overall all-cause mortality after surgery.ConclusionConcomitant valve surgery was considerably related to a higher risk of postoperative mortality in patients with post-infarction ventricle aneurysms who underwent surgical treatments. No significant difference in the prognosis outcomes was observed between the operating methods of repair or replacement valve surgery
雷公藤红素通过靶向核受体Nur77促进损伤线粒体自噬而抑制炎症反应
文章简介线粒体在细胞死亡、自噬、免疫和炎症中起着不可或缺的作用。前期研究发现,孤儿核受体Nur77通过靶向线粒体诱导细胞凋亡。本文报道了Nur77作为具有抗炎作用的雷公藤红素的直接靶点,介导雷公藤红素通过自噬清除损伤线粒体,抑制炎症反应而达到治疗炎症疾病包括肥胖症的功能。研究人员发现,雷公藤红素的结合
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