bluuebunny/crossref_metadata_2025_split huggingface dataset:
Iterated monodromy groups of quadratic polynomials, I
Authors: Bartholdi Laurent , Nekrashevych Volodymyr V. 
Published: December 2009

We describe the iterated monodromy groups associated with post-critically finite quadratic polynomials, and make explicit their connection to the ‘kneading sequence’ of the polynomial.
We then give recursive presentations by generators and relations for these groups, and study some of their properties, like torsion and ‘branchness’.
Local similarities and the Haagerup property (with an appendix by Daniel S. Farley)
Authors: Hughes Bruce 
Published: December 2009

A new class of groups, the locally finitely determined groups of local similarities on compact ultrametric spaces, is introduced and it is proved that these groups have the Haagerup property (that is, they are a-T-menable in the sense of Gromov). The class includes Thompson's groups, which have already been shown to have the Haagerup property by D. S. Farley, as well as many other groups acting on boundaries of trees. A sufficient condition, used in this article, for the Haagerup property is shown in the appendix by D. S. Farley to be equivalent to the well-known property of having a proper action on a space with walls.
On growth and torsion of groups
Authors: Bartholdi Laurent , Pochon Floriane 
Published: December 2009

We give a subexponential upper bound and a superpolynomial lower bound on the growth function of the Fabrykowski–Gupta group.
As a consequence, we answer negatively a question by Longobardi, Maj and Rhemtulla about characterizing groups containing no free subsemigroups on two generators.
A note on a critical problem with natural growth in the gradient
Authors: Abdellaoui Boumediene , Peral Alonso Ireneo 
Published: December 2009

The paper analyzes the influence on the meaning of natural growth in the gradient, of a perturbation by a Hardy potential in some elliptic equations. We obtain a linear differential operator that, in a natural way, is the corresponding gradient for the perturbed elliptic problem.
The main results are: i) Optimal summability of the data to have weak solutions; ii) Optimal linear operator associated, and, iii) Multiplicity and characterization of all solutions in terms of some measures. The results also are new for the Laplace operator perturbed for an inverse-square potential.
Geometric Numerical Integration
Authors: Hairer Ernst , Hochbruck Marlis , Iserles Arieh , Lubich Christian 
Published: December 2009

The subject of this workshop was numerical methods that preserve geometric properties of the flow of an ordinary or partial differential equation: symplectic and multisymplectic integrators for Hamiltonian systems, symmetric integrators for reversible systems, methods preserving first integrals and numerical methods on manifolds, inclusive of Lie group methods and integrators for constrained mechanical systems, and methods for problems with highly oscillatory solutions. The unifying theme was structure preservation: not just the “how?” but also “why?”, “where?” and “what for?”.
The motivation for developing structure-preserving algorithms for special classes of problems originates independently in such diverse areas of research as astronomy, molecular dynamics, mechanics, control theory, theoretical physics and numerical analysis, with important contributions from other areas of both applied and pure mathematics. Moreover, it turns out that preservation of geometric properties of the flow not only produces an improved qualitative behaviour, but also allows for a significantly more accurate long-time integration than with general-purpose methods.
In addition to the construction of geometric integrators, an important aspect of geometric integration is the light it sheds on the relationship between geometric properties of a numerical method and favourable error propagation in long-time integration. A very successful organising principle is backward error analysis, whereby the numerical one-step map is interpreted as (almost) the flow of a modified differential equation. In this way, geometric properties of the numerical integrator translate seamlessly into structure preservation on the level of the modified equation. Much insight and rigourous error estimates over long time intervals can then be obtained by combining backward error analysis with the KAM theory and related perturbation theories for Hamiltonian and reversible systems. While this approach has been very successful for ordinary differential equations, much less is currently known about highly oscillatory systems and geometric integrators for partial differential equations.
Geometric numerical integration has been an active interdisciplinary research area since the last decade. Although the subject is in a lively phase of intensive development, the results so far are substantive and they impact on a wide range of application areas and on our understanding of core issues in computational mathematics. This is evidenced by the monographs [1, 2].
Explicit Methods in Number Theory
Authors: Cohen Henri , Lenstra, Jr. Hendrik W. , Zagier Don B. 
Published: December 2009

The workshop
Explicit Methods in Number Theory
was organised by Henri Cohen (Talence), Hendrik W. Lenstra (Leiden), and Don B. Zagier (Bonn), with the assistance of Karim Belabas (Talence), and it took place July 15–21, 2007. Four previous workshops on the topic had been held in 1999, 2001, 2003, and 2005. The goal of the meeting was to present new methods and results on concrete aspects of number theory. In several cases, this included algorithmic and experimental work, but the emphasis was on the implications for number theory.

There were three ‘mini-series’ highlighting important recent developments: one of three hours, by Jordan Ellenberg and Akshay Venkatesh, on asymptotics for field extensions and class numbers; one of two hours by Mark Watkins, on random matrices and

L

-functions; and one of three hours by Noam Elkies, on the construction of elliptic curves of high Mordell–Weil rank.

Some of the other themes were:
As always in Oberwolfach, the atmosphere was lively and active, providing an ideal environment for the exchange of ideas and productive discussions. The meeting was well-attended, with 51 participants from a variety of backgrounds, including a large number of younger researchers. There were 32 talks of various lengths, and ample time was allotted to informal collaboration.
Compléments sur les opérateurs précompacts et faiblements compacts positifs <br>Complement on positive precompact and weakly compact operators
Authors: Aqzzouz Belmesnaoui , Nouira Redouane 
Published: December 2009

Nous établissons deux conditions nécessaires concernant le problème de domination, l'une pour les opérateurs précompacts positifs et l'autre pour les opérateurs faiblement compacts positifs.
We prove two necessary conditions about the domination problem, one for positive precompact operators and the other for positive weakly compact operators.
Irréductibilité et spécialisation des polynômes
Authors: Najib Salah 
Published: December 2009

À partir de la décomposition en base b(X) (un polynôme non constant), nous donnons un critère d'irréductibilité des polynômes en deux variables. Puis nous étudions un problème de spécialisation qui a un lien avec le théorème d'irréductibilité de Hilbert.
Starting from the decomposition in base b(X) (a nonconstant polynomial), we give an irreducibility criterion of the bivariate polynomials. Moreover we study a problem of specialization which has a link with Hilbert’s irreducibility theorem.
Axial impact on a semi-infinite elastic rod
Authors: Villaggio Piero 
Published: December 2009

An approximate theory for treating the axial collision of a rigid mass against an elastic rod was proposed by Saint–Venant more than 150 years ago. The method works only for short bars, under the assumption that the elastic axial displacement instantaneously propagates from one end to the other after the impact. Moreover, this hypothesis is unrealistic for long rods.
Here we suggest an extension of the method which is able to treat the axial impact on the initial cross-section of a semi-infinite rod.
Editorial note
Authors: Ambrosetti Antonio 
Published: December 2009

Editorial Note
On the occasion of the thirtieth anniversary of the death of Guido Stampacchia (1922-1978), the International Conference “Recent trends in nonlinear partial differential equations” has been organised by some of his former colleagues and students at the Accademia dei Lincei in Roma, November 6, 2008.
Stampacchia was the President of the Unione Matematica Italiana in the period of 1967-1973, and a very active member of the Accademia dei Lincei. One of the leaders of the Italian school of partial differential equations, his contributions to differential equations, calculus of variations and variational inequalities are well known. His popularity in the Italian mathematical community explains very well the participation of so many researchers in the Conference.
After the opening addresses by Enrico Magenes and David Kinderlehrer, plenary lectures were given by Louis Nirenberg, Haïm Brezis, Lucio Boccardo, Vieri Benci, Henry Berestycki and Luis Caffarelli. Some of the speakers have gladly agreed to write up their lectures and Rendiconti Lincei - Matematica e Applicazioni is proud to publish them. The paper by Brezis already appeared in vol. XIX (2008), No 4, pp. 335-338 while others are collected in the present issue.
The Editor-in-ChiefAntonio Ambrosetti
Loss of Medicaid Coverage During the Renewal Process
Authors: Dague Laura , Myerson Rebecca 
Published: May 2024

ImportanceMedicaid beneficiaries must periodically redemonstrate their eligibility in a process that is called renewal, redetermination, or recertification. The number and characteristics of people who lose Medicaid coverage due to renewal requirements are not known.ObjectiveTo measure the proportion of people who lose Medicaid coverage at the renewal deadline, overall and by enrollee characteristics, and time until regaining Medicaid coverage among those losing coverage at the deadline.Design, Setting, and ParticipantsThis cohort study tracked the duration of Medicaid enrollment among Wisconsin Medicaid enrollees with a 12-month renewal deadline. Data were collected for all nonelderly (aged &amp;lt;65 years) new enrollees from January 2016 through January 2018, except those enrolled due to disability or pregnancy. Individuals were followed through January 2020 to provide at least 24 months of data on each enrollment spell. Data were analyzed from August 2023 to February 2024.Main Outcomes and MeasuresThe primary outcome was coverage loss during the renewal process, defined as a loss in Medicaid coverage from month 12 to month 13 for people who were still enrolled at the start of month 12. Secondary outcomes included coverage loss prior to the renewal deadline and the duration of the gap in Medicaid coverage among those who lost coverage during the renewal process.ResultsThe study sample included 684 245 Medicaid enrollment spells across 586 044 people (51% female and 47% children 18 years or younger). Among enrollees, 20% lost Medicaid coverage at the renewal deadline. Of those who lost coverage, 37% regained Medicaid coverage within 6 months, and an additional 10% regained coverage within 12 months. Children younger than 12 years and people with more Medicaid-covered health care (top quartile of Medicaid-covered health care costs during the first 6 months of enrollment) were less likely than other groups to lose coverage during the renewal process (15% and 6% lost coverage at renewal, respectively) and more likely to regain Medicaid quickly. Personal characteristics such as gender and race and ethnicity remained associated with the risk of losing Medicaid at the renewal deadline after adjustment for baseline household income, enrollment group, and past use of Medicaid services.Conclusions and RelevanceIn this cohort study, the risk of coverage loss during the Medicaid renewal process was associated with age, past use of care, and other personal characteristics. These findings shed light on how renewal requirements shape access to Medicaid.
A Precursor‐Derived Ultramicroporous Carbon for Printing Iontronic Logic Gates and Super‐Varactors
Authors: Gellrich Christin , Shupletsov Leonid , Galek Przemyslaw , Bahrawy Ahmed , Grothe Julia , Kaskel Stefan 
Published: May 2024

AbstractA liquid precursor for 3D printing ultramicroporous carbons (pore width <0.7 nm) to create a novel in‐plane capacitive‐analog of semiconductor‐based diodes (CAPodes) is presented. This proof‐of‐concept integrates functional EDLCs into microstructured iontronic devices. The working principle is based on selective ion‐sieving, controlling the size of the electrolyte ions, and the nanoporous sieving carbon's pore size. By blocking bulky electrolyte ions from entering the sub‐nanometer pores, a unidirectional charging characteristic with controllable ion flux is achieved, leading to diodic U‐I characteristics with a high rectification ratio. The liquid precursor approach enables successful printing of miniaturized in‐plane CAPodes. A combination of inkjet and extrusion printing techniques with suitable inks is explored to fabricate electrode materials with engineered porosity. Deliberate fine‐tuning of the ultramicroporous carbon's porosity and surface area is achieved using a customized carbon precursor and CO2 etching techniques. Electrochemical evaluation of the printed CAPodes demonstrates successful miniaturization compared with macroscopic film assembly. 3D manufacturing and miniaturization allow for the integration of CAPodes into logic gate circuits (OR, AND). For the first time, these switchable devices are used as variable capacitors in a high‐pass filter application, adjusting the cut‐off frequency of applied alternating voltage analogous to an I‐MOS varactor.
Flexible Ultrasonic‐Induced Wireless Energy Conversion Technology in Implantable Biomedicine
Authors: Qin Xingchen , Zhang Zhiyuan , Zheng Shaodi , Huang Yuepeng , Cai Jiancheng , Chen Chaoqian , Xu Zisheng , E Shiju 
Published: May 2024

AbstractNumerous associated challenges arise with the advancement and continuous improvement of implantable medical devices, such as the frequent requirement for battery replacement. The flexible ultrasonic‐induced wireless energy conversion (UWEC) technology has garnered significant interest due to its superior energy transmission efficiency, safety, and biocompatibility compared to traditional electromagnetic wireless energy conversion technology. This paper provides a comprehensive review of the recent advancements in two types of flexible UWEC technologies, triboelectric nanogenerators, and piezoelectret nanogenerators, with a focus on their applications in implantable medical treatments. First, the energy conversion principles and general materials of flexible UWEC are presented. Then, the research and application of flexible UWEC devices are introduced in detail based on their medical functions. At the end of this review, perspectives and opportunities are discussed.
NIR‐II Ratiometric Fluorescent Nanoplatform for Real‐Time Monitoring and Evaluating Cancer Sonodynamic Therapy Efficacy
Authors: Yang Kaiqiong , Tang Huaiding , Zhang Yiping , Wu Ying , Su Lichao , Zhang Xuan , Du Wei , Zhang Jieping , Wang Guoyu , Liu Daojia , Chen Ling , Chen Junqiang , Song Jibin 
Published: May 2024

AbstractReal‐time monitoring the therapeutic process of sonodynamic therapy (SDT) is essential to optimize the treatment course in time and eventually improve the efficacy. The generation of singlet oxygen (1O2) is a quintessential characteristic of SDT, which permits non‐invasive monitoring of SDT by real‐time imaging of 1O2 inside the tumor. Nonetheless, the majority of probes are unable to measure 1O2 in real time because of its short half‐life and strong oxidative capacity. Here, the study constructs a ratiometric nanoplatform (DTPI) utilizing two fluorescent probes and the sonosensitizer TiO2. The poisonous 1O2 generated by DTPI following ultrasonic (US) radiation efficiently destroys tumor cells. The structural disruption of fluorescent dye IR‐1061 by 1O2 leads to a reduction in the DTPI fluorescence signal at 1100 nm, while US radiation has no impact on the fluorescence signal at 1550 nm. Thus, DTPI provides a precise and consistent reflection of the treatment efficacy at the tumor site, leveraging the ratiometric fluorescence signal and variations in oxygen content throughout the treatment process. This ratiometric‐fluorescence‐based reflection strategy establishes an effective and dependable platform for the real‐time monitoring and assessment of the cancer therapeutic effect through ratiometric probes.
Mesoporous Palladium Catalyst for Efficient Electrochemical Semi‐Hydrogenation of Alkynes
Authors: Jia Fengrui , Sun Lizhi , Yang Feng , Xiao Jie , Yao Huiqin , Liu Ben 
Published: May 2024

AbstractDeveloping robust electrocatalysts for efficient semi‐hydrogenation of alkynes to markedly important alkenes is highly desirable in both research and industry areas. In this work, it is reported that robust palladium mesoporous nanospheres (Pd MSs) with electron‐rich active sites perform perfectly as cathode electrocatalyst for electrochemical semi‐hydrogenation of alkynes in water. In comparison to its counterparts, Pd MSs hold remarkable conversion (97%), superior selectivity (98%), good operation stability in selective semi‐hydrogenation of p‐aminophenylene. High performance is assigned to electron‐rich Pd sites within mesopores that not only favor the formation of active H* but also accelerate the desorption of p‐aminostyrene. Meanwhile, Pd MSs are also highly efficient in selective semi‐hydrogenation of various terminal alkynes with different substituents. It is thus expected that robust Pd MSs can be demonstrated as an alternative catalyst design paradigm for other electrochemical hydrogenation reactions.
Erasable and Field Programmable DNA Circuits Based on Configurable Logic Blocks
Authors: Liu Yizhou , Zhai Yuxuan , Hu Hao , Liao Yuheng , Liu Huan , Liu Xiao , He Jiachen , Wang Limei , Wang Hongxun , Li Longjie , Zhou Xiaoyu , Xiao Xianjin 
Published: May 2024

AbstractDNA is commonly employed as a substrate for the building of artificial logic networks due to its excellent biocompatibility and programmability. Till now, DNA logic circuits are rapidly evolving to accomplish advanced operations. Nonetheless, nowadays, most DNA circuits remain to be disposable and lack of field programmability and thereby limits their practicability. Herein, inspired by the Configurable Logic Block (CLB), the CLB‐based erasable field‐programmable DNA circuit that uses clip strands as its operation‐controlling signals is presented. It enables users to realize diverse functions with limited hardware. CLB‐based basic logic gates (OR and AND) are first constructed and demonstrated their erasability and field programmability. Furthermore, by adding the appropriate operation‐controlling strands, multiple rounds of programming are achieved among five different logic operations on a two‐layer circuit. Subsequently, a circuit is successfully built to implement two fundamental binary calculators: half‐adder and half‐subtractor, proving that the design can imitate silicon‐based binary circuits. Finally, a comprehensive CLB‐based circuit is built that enables multiple rounds of switch among seven different logic operations including half‐adding and half‐subtracting. Overall, the CLB‐based erasable field‐programmable circuit immensely enhances their practicability. It is believed that design can be widely used in DNA logic networks due to its efficiency and convenience.
Ethnoprimatology reveals new extended distribution of critically endangered banded langur Presbytis femoralis (Martin, 1838) in Pahang, Malaysia: Insights from indigenous traditional knowledge and molecular analysis
Authors: Haris Hidayah , Othman Nursyuhada , Kaviarasu Munian , Najmuddin Muhammad Faudzir , Abdullah‐Fauzi Nurfatiha Akmal Fawwazah , Ramli Farah Farhana , Sariyati Nur Hartini , Ilham‐Norhakim Mohd Lokman , Md‐Zain Badrul Munir , Abdul‐Latiff Muhammad Abu Bakar 
Published: May 2024

AbstractThe banded langur (Presbytis femoralis) is a critically endangered primate, which within Malaysia has not been known to extend significantly outside the state of Johor. Traditionally, distribution studies on this highly threatened primate have relied on conventional methods such as DNA identification, live counting, and camera trapping. However, ethnoprimatology offers an alternative approach to data collection, involving the active participation of indigenous and local communities possessing valuable knowledge and experience with local primate species. This study employed an integrated approach incorporating ethnoprimatology by utilizing pooled local expert opinion, local surveys, interviews, and fecal DNA analysis, resulting in a novel distribution range for the banded langur. The combination of expert opinions revealed this species' most optimistic distribution scenario across Johor and Pahang, inhabiting various ecosystems, including lowland forests, peat swamps, and human‐modified landscapes. Further interviews and surveys conducted within the Orang Asli community in Tasik Chini and Tasek Bera have provided additional support for the revised distribution, documenting occurrences of banded langur utilization in indigenous practices, such as food consumption, cultural beliefs, medicinal applications, and craftsmanship. Phylogenetic analysis demonstrated genetic differentiation between populations in Johor and Pahang, with the populations in the southern part of Peninsular Malaysia likely serving as ancestral sources for other populations. Consequently, this study not only elucidated the updated distribution of banded langur through DNA records and direct observations but also established the efficacy of ethnoprimatology as a precursory tool for uncovering the present distribution patterns of other primate species in Malaysia.
β‐Phenethylamine Synthesis: N‐Pyridinium Aziridines as Latent Dual Electrophiles
Authors: Samanta Samya , Biswas Promita , O'Bannon Braeden C. , Powers David C. 
Published: May 2024

Abstractβ‐Phenethylamines are widely represented in biologically and pharmacologically active organic small molecules. Here, we introduce N‐pyridinium aziridines as latent dual electrophiles for the synthesis of β‐phenethylamines. Bromide‐promoted ring opening generates β‐halopyridinium amines. Selective Ni‐catalyzed C−C cross‐coupling between organozinc nucleophiles and the benzylic C−Br electrophile affords a diverse family of β‐functionalized phenethylaminopyridinium salts, and coupling is stereoconvergent in the presence of chiral ligands. Subsequent Ni‐catalyzed reductive N−N bond activation within the β‐functionalized phenethylaminopyridinium salts furnishes the products of formal olefin carboamination. Other reductive N−N cleavage reactions are demonstrated to provide access to free primary amines, alkylated amines, heterocycles, and products derived from N‐centered radical chemistry. The developed reaction sequence can be implemented in the context of complex molecules and natural product derivatives. Together, the described results provide a general and modular synthesis of β‐phenethylamines and significantly expand the utility of N‐pyridinium aziridines as linchpins in chemical synthesis.