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Article ; Online: Correction to: Do Couple-Based Interventions Show Larger Efects in Promoting HIV Preventive Behaviors than Individualized Interventions in Couples? A Systematic Review and Meta-analysis of 11 Randomized Controlled Trials.

Fu, Rong / Hou, Jianhua / Gu, Yuzhou / Yu, Nancy Xiaonan

2023

Language	English
Publishing date	2023-05-23
Publishing country	United States
Document type	Published Erratum
ZDB-ID	1339885-4
ISSN	1573-3254 ; 1090-7165
ISSN (online)	1573-3254
ISSN	1090-7165
DOI	10.1007/s10461-023-04080-6
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Article ; Online: Coulomb blockade and Coulomb staircases in CoBi nanoislands on SrTiO

Xia, Yumin / Cai, Desheng / Gao, Jiaqing / Li, Pengju / Xie, Kun / Liu, Yuzhou / Gu, Yitong / Yu, Gan / Cui, Ping / Qin, Shengyong

Nanotechnology

2024 Volume 35, Issue 29

Abstract: We successfully fabricated two-dimensional metallic CoBi nanoislands on ... ...

Abstract	We successfully fabricated two-dimensional metallic CoBi nanoislands on SrTiO
Language	English
Publishing date	2024-04-30
Publishing country	England
Document type	Journal Article
ZDB-ID	1362365-5
ISSN	1361-6528 ; 0957-4484
ISSN (online)	1361-6528
ISSN	0957-4484
DOI	10.1088/1361-6528/ad1943
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Book ; Online: Fast Sampling of $b$-Matchings and $b$-Edge Covers

Chen, Zongchen / Gu, Yuzhou

2023

Abstract: For integer $b \ge 1$, a $b$-matching (resp. $b$-edge cover) of a graph $G=(V,E)$ is a subset $S\subseteq E$ of edges such that every vertex is incident with at most (resp. at least) $b$ edges from $S$. We prove that for any $b \ge 1$ the simple Glauber ... ...

Abstract	For integer $b \ge 1$, a $b$-matching (resp. $b$-edge cover) of a graph $G=(V,E)$ is a subset $S\subseteq E$ of edges such that every vertex is incident with at most (resp. at least) $b$ edges from $S$. We prove that for any $b \ge 1$ the simple Glauber dynamics for sampling (weighted) $b$-matchings and $b$-edge covers mixes in $O(n\log n)$ time on all $n$-vertex bounded-degree graphs. This significantly improves upon previous results which have worse running time and only work for $b$-matchings with $b \le 7$ and for $b$-edge covers with $b \le 2$. Moreover generally, we prove spectral independence for a broad class of binary symmetric Holant problems with log-concave signatures, including $b$-matchings, $b$-edge covers, and antiferromagnetic $2$-spin edge models. We hence deduce optimal mixing time of Glauber dynamics from spectral independence.
Keywords	Computer Science - Data Structures and Algorithms ; Computer Science - Discrete Mathematics ; Mathematics - Combinatorics ; Mathematics - Probability
Subject code	519 ; 511
Publishing date	2023-04-27
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Book ; Online: Optimal Bounds for Noisy Sorting

Gu, Yuzhou / Xu, Yinzhan

2023

Abstract: Sorting is a fundamental problem in computer science. In the classical setting, it is well-known that $(1\pm o(1)) n\log_2 n$ comparisons are both necessary and sufficient to sort a list of $n$ elements. In this paper, we study the Noisy Sorting problem, ...

Abstract	Sorting is a fundamental problem in computer science. In the classical setting, it is well-known that $(1\pm o(1)) n\log_2 n$ comparisons are both necessary and sufficient to sort a list of $n$ elements. In this paper, we study the Noisy Sorting problem, where each comparison result is flipped independently with probability $p$ for some fixed $p\in (0, \frac 12)$. As our main result, we show that $$(1\pm o(1)) \left( \frac{1}{I(p)} + \frac{1}{(1-2p) \log_2 \left(\frac{1-p}p\right)} \right) n\log_2 n$$ noisy comparisons are both necessary and sufficient to sort $n$ elements with error probability $o(1)$ using noisy comparisons, where $I(p)=1 + p\log_2 p+(1-p)\log_2 (1-p)$ is capacity of BSC channel with crossover probability $p$. This simultaneously improves the previous best lower and upper bounds (Wang, Ghaddar and Wang, ISIT 2022) for this problem. For the related Noisy Binary Search problem, we show that $$ (1\pm o(1)) \left((1-\delta)\frac{\log_2(n)}{I(p)} + \frac{2 \log_2 \left(\frac 1\delta\right)}{(1-2p)\log_2\left(\frac {1-p}p\right)}\right) $$ noisy comparisons are both necessary and sufficient to find the predecessor of an element among $n$ sorted elements with error probability $\delta$. This extends the previous bounds of (Burnashev and Zigangirov, 1974), which are only tight for $\delta = 1/n^{o(1)}$. Comment: To appear at STOC'23; fixed issues in the previous version
Keywords	Computer Science - Data Structures and Algorithms ; Computer Science - Information Theory
Subject code	003
Publishing date	2023-02-23
Publishing country	us
Document type	Book ; Online
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Book ; Online: Weak Recovery Threshold for the Hypergraph Stochastic Block Model

Gu, Yuzhou / Polyanskiy, Yury

2023

Abstract: We study the weak recovery problem on the $r$-uniform hypergraph stochastic block model ($r$-HSBM) with two balanced communities. In HSBM a random graph is constructed by placing hyperedges with higher density if all vertices of a hyperedge share the ... ...

Abstract	We study the weak recovery problem on the $r$-uniform hypergraph stochastic block model ($r$-HSBM) with two balanced communities. In HSBM a random graph is constructed by placing hyperedges with higher density if all vertices of a hyperedge share the same binary label, and weak recovery asks to recover a non-trivial fraction of the labels. We introduce a multi-terminal version of strong data processing inequalities (SDPIs), which we call the multi-terminal SDPI, and use it to prove a variety of impossibility results for weak recovery. In particular, we prove that weak recovery is impossible below the Kesten-Stigum (KS) threshold if $r=3,4$, or a strength parameter $\lambda$ is at least $\frac 15$. Prior work Pal and Zhu (2021) established that weak recovery in HSBM is always possible above the KS threshold. Consequently, there is no information-computation gap for these cases, which (partially) resolves a conjecture of Angelini et al. (2015). To our knowledge this is the first impossibility result for HSBM weak recovery. As usual, we reduce the study of non-recovery of HSBM to the study of non-reconstruction in a related broadcasting on hypertrees (BOHT) model. While we show that BOHT's reconstruction threshold coincides with KS for $r=3,4$, surprisingly, we demonstrate that for $r\ge 7$ reconstruction is possible also below KS. This shows an interesting phase transition in the parameter $r$, and suggests that for $r\ge 7$, there might be an information-computation gap for the HSBM. For $r=5,6$ and large degree we propose an approach for showing non-reconstruction below KS, suggesting that $r=7$ is the correct threshold for onset of the new phase.
Keywords	Mathematics - Probability ; Computer Science - Information Theory
Publishing date	2023-03-26
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Book ; Online: Uniqueness of BP fixed point for the Potts model and applications to community detection

Gu, Yuzhou / Polyanskiy, Yury

2023

Abstract: In the study of sparse stochastic block models (SBMs) one often needs to analyze a distributional recursion, known as the belief propagation (BP) recursion. Uniqueness of the fixed point of this recursion implies several results about the SBM, including ... ...

Abstract	In the study of sparse stochastic block models (SBMs) one often needs to analyze a distributional recursion, known as the belief propagation (BP) recursion. Uniqueness of the fixed point of this recursion implies several results about the SBM, including optimal recovery algorithms for SBM (Mossel et al. (2016)) and SBM with side information (Mossel and Xu (2016)), and a formula for SBM mutual information (Abbe et al. (2021)). The 2-community case corresponds to an Ising model, for which Yu and Polyanskiy (2022) established uniqueness for all cases. In this paper we analyze the $q$-ary Potts model, i.e., broadcasting of $q$-ary spins on a Galton-Watson tree with expected offspring degree $d$ through Potts channels with second-largest eigenvalue $\lambda$. We allow the intermediate vertices to be observed through noisy channels (side information). We prove that BP uniqueness holds with and without side information when $d\lambda^2 \ge 1 + C \max\{\lambda, q^{-1}\}\log q$ for some absolute constant $C>0$ independent of $q,\lambda,d$. For large $q$ and $\lambda = o(1/\log q)$, this is asymptotically achieving the Kesten-Stigum threshold $d\lambda^2=1$. These results imply mutual information formulas and optimal recovery algorithms for the $q$-community SBM in the corresponding ranges. For $q\ge 4$, Sly (2011); Mossel et al. (2022) showed that there exist choices of $q,\lambda,d$ below Kesten-Stigum (i.e. $d\lambda^2 < 1$) but reconstruction is possible. Somewhat surprisingly, we show that in such regimes BP uniqueness does not hold at least in the presence of weak side information. Our technical tool is a theory of $q$-ary symmetric channels, that we initiate here, generalizing the classical and widely-utilized information-theoretic characterization of BMS (binary memoryless symmetric) channels.
Keywords	Mathematics - Probability ; Computer Science - Information Theory
Publishing date	2023-03-26
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Tying Covalent Organic Frameworks through Alkene Metathesis and Supported Platinum as Efficient Catalysts for Hydrosilylation

Defa Gu / Guangwen Li / Yushan Liu / Yuzhou Liu

Nanomaterials, Vol 12, Iss 499, p

2022 Volume 499

Abstract: Recently there has been a great interest in covalent organic frameworks due to their fascinating properties. Current approaches to improve their hydrolytic stability mainly rely on the transformation of the dynamic bonds into strong and irreversible ... ...

Abstract	Recently there has been a great interest in covalent organic frameworks due to their fascinating properties. Current approaches to improve their hydrolytic stability mainly rely on the transformation of the dynamic bonds into strong and irreversible bonds, but these approaches also reduce the versatility of the frameworks. Herein, we would like to demonstrate a solution to this dilemma by forming hierarchical bonds through olefin metathesis to produce highly stable COFs. Our approach allows unprecedented opportunities for post-modification of the inner space through the dynamic imine bonds while maintaining the integrity of the framework. Specifically, we demonstrate an amorphous-to-crystalline transformation. In addition, the porosity can be enhanced by up to 70% after full removal of the amine subunits. Overall, our work provides a new direction for the generation of highly stable while still versatile COFs. Meanwhile, platinum(II) complexes can be supported on BHU-2 (Pt@BHU-2) or BHU-2-Oxidate(Pt@BHU-2-Oxidate) as efficient catalysts for hydrosilylation.
Keywords	hydrolytic stability ; hierarchical bond formation ; alkene metathesis ; hydrosilylation ; Chemistry ; QD1-999
Subject code	540
Language	English
Publishing date	2022-01-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: Tying Covalent Organic Frameworks through Alkene Metathesis and Supported Platinum as Efficient Catalysts for Hydrosilylation.

Gu, Defa / Li, Guangwen / Liu, Yushan / Liu, Yuzhou

Nanomaterials (Basel, Switzerland)

2022 Volume 12, Issue 3

Abstract	Recently there has been a great interest in covalent organic frameworks due to their fascinating properties. Current approaches to improve their hydrolytic stability mainly rely on the transformation of the dynamic bonds into strong and irreversible bonds, but these approaches also reduce the versatility of the frameworks. Herein, we would like to demonstrate a solution to this dilemma by forming hierarchical bonds through olefin metathesis to produce highly stable COFs. Our approach allows unprecedented opportunities for post-modification of the inner space through the dynamic imine bonds while maintaining the integrity of the framework. Specifically, we demonstrate an amorphous-to-crystalline transformation. In addition, the porosity can be enhanced by up to 70% after full removal of the amine subunits. Overall, our work provides a new direction for the generation of highly stable while still versatile COFs. Meanwhile, platinum(II) complexes can be supported on BHU-2 (Pt@BHU-2) or BHU-2-Oxidate(Pt@BHU-2-Oxidate) as efficient catalysts for hydrosilylation.
Language	English
Publishing date	2022-01-31
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2662255-5
ISSN	2079-4991
ISSN	2079-4991
DOI	10.3390/nano12030499
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Book ; Online: Low Rank Matrix Completion via Robust Alternating Minimization in Nearly Linear Time

Gu, Yuzhou / Song, Zhao / Yin, Junze / Zhang, Lichen

2023

Abstract: Given a matrix $M\in \mathbb{R}^{m\times n}$, the low rank matrix completion problem asks us to find a rank-$k$ approximation of $M$ as $UV^\top$ for $U\in \mathbb{R}^{m\times k}$ and $V\in \mathbb{R}^{n\times k}$ by only observing a few entries masked ... ...

Abstract	Given a matrix $M\in \mathbb{R}^{m\times n}$, the low rank matrix completion problem asks us to find a rank-$k$ approximation of $M$ as $UV^\top$ for $U\in \mathbb{R}^{m\times k}$ and $V\in \mathbb{R}^{n\times k}$ by only observing a few entries masked by a binary matrix $P_{\Omega}\in \{0, 1 \}^{m\times n}$. As a particular instance of the weighted low rank approximation problem, solving low rank matrix completion is known to be computationally hard even to find an approximate solution [RSW16]. However, due to its practical importance, many heuristics have been proposed for this problem. In the seminal work of Jain, Netrapalli, and Sanghavi [JNS13], they show that the alternating minimization framework provides provable guarantees for low rank matrix completion problem whenever $M$ admits an incoherent low rank factorization. Unfortunately, their algorithm requires solving two exact multiple response regressions per iteration and their analysis is non-robust as they exploit the structure of the exact solution. In this paper, we take a major step towards a more efficient and robust alternating minimization framework for low rank matrix completion. Our main result is a robust alternating minimization algorithm that can tolerate moderate errors even though the regressions are solved approximately. Consequently, we also significantly improve the running time of [JNS13] from $\widetilde{O}(mnk^2 )$ to $\widetilde{O}(mnk )$ which is nearly linear in the problem size, as verifying the low rank approximation takes $O(mnk)$ time. Our core algorithmic building block is a high accuracy regression solver that solves the regression in nearly linear time per iteration.
Keywords	Computer Science - Machine Learning ; Computer Science - Data Structures and Algorithms ; Mathematics - Optimization and Control ; Statistics - Machine Learning
Subject code	518
Publishing date	2023-02-21
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Communal or Autonomous? Coping Experiences of Chinese Serodiscordant Male Couples to HIV Care: A Dyadic Qualitative Analysis.

Fu, Rong / Chen, Chen / Gu, Yuzhou / Wu, Dan / Darbes, Lynae A / Yu, Nancy Xiaonan

Archives of sexual behavior

2023 Volume 52, Issue 8, Page(s) 3553–3564

Abstract: Limited empirical evidence exists on the interpersonal challenges faced by Chinese serodiscordant male couples in HIV care. This study aimed to explore their coping experiences in HIV care by applying the communal coping process theoretical framework. A ... ...

Abstract	Limited empirical evidence exists on the interpersonal challenges faced by Chinese serodiscordant male couples in HIV care. This study aimed to explore their coping experiences in HIV care by applying the communal coping process theoretical framework. A dyadic qualitative study using face-to-face interviews with 20 serodiscordant male couples (n = 40) was conducted between July and September 2021 in two Chinese metropolitan areas through purposive sampling. Eligibility included one partner living with HIV and the other being HIV-negative, both aged 18 or older, born male, gay or bisexual, and in a relationship together for at least 3 months. A hybrid deductive-inductive approach integrated with dyadic interview analysis and framework method was used for data analysis. We identified three themes in the coping process in HIV care: (1) coping as an autonomous process, (2) coping as a dissonant process, and (3) coping as a contextualized communal process. Concerning autonomous coping, most couples adopted either disengaged avoidance or mutual noninvolvement as negative coping strategies. We also identified potential risk factors for dissonant coping, which are a partner living with internalized HIV stigma and the couple's asymmetric relationship goals. Our results indicate the communal coping process of HIV care is contextual, and our expansion of the communal coping theory sheds light on how serodiscordant male couples cope with stressors connected to HIV care. Our findings provide theoretical insights for the development of dyadic interventions based on health psychology for Chinese serodiscordant male couples to engage in HIV care.
MeSH term(s)	Humans ; Male ; HIV Infections/psychology ; Risk Factors ; Social Stigma ; Sexual Partners/psychology ; China
Language	English
Publishing date	2023-06-26
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	184221-3
ISSN	1573-2800 ; 0004-0002
ISSN (online)	1573-2800
ISSN	0004-0002
DOI	10.1007/s10508-023-02643-1
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