Abstract Seismic noise and local disturbances are dominant noise sources for ground-based gravitational waves detectors in the low frequency region (0.1–10 Hz) limiting their sensitivity and duty ...cycle. With the introduction of high-performance seismic isolation systems based on mechanical pendula, the 2nd generation laser interferometric detectors have reached the scientific goal of the first direct observation of GW signals thanks to the extension of the detection bandwidth down to 10 Hz. Now, the 3rd generation instrument era is approaching, and the Einstein telescope giant interferometer is becoming a reality with the possibility to install the detector in an underground site where seismic noise is 100 times smaller than on surface. Moreover, new available technologies as well as the experience acquired in operating advanced detectors are key points to further extend the detection bandwidth down to 2 Hz with the possibility to suspend cryogenic payload and then mitigating thermal noise too. Here, we present a preliminary study devoted to improving seismic attenuation performance of the advanced VIRGO superattenuator in the low frequency region of about five orders of magnitude. Particular care has been carried on in analyzing the possibility to improve the vertical attenuation performance with a multi-stage pendulum chain equipped with magnetic anti-springs that is hung to a double inverted pendulum in nested configuration. The feedback control requirements and possible strategies to be adopted for this last element will be presented.
3-Flows and Combs da Silva, Cândida Nunes; Lucchesi, Cláudio L.
Journal of graph theory,
December 2014, Letnik:
77, Številka:
4
Journal Article
Recenzirano
Tutte's 3‐Flow Conjecture states that every 2‐edge‐connected graph with no 3‐cuts admits a 3‐flow. The 3‐Flow Conjecture is equivalent to the following: let G be a 2‐edge‐connected graph, let S be a ...set of at most three vertices of G; if every 3‐cut of G separates S then G has a 3‐flow. We show that minimum counterexamples to the latter statement are 3‐connected, cyclically 4‐connected, and cyclically 7‐edge‐connected.
Laminar tight cuts in matching covered graphs Chen, Guantao; Feng, Xing; Lu, Fuliang ...
Journal of combinatorial theory. Series B,
September 2021, 2021-09-00, Letnik:
150
Journal Article
Recenzirano
Odprti dostop
An edge cut C of a graph G is tight if |C∩M|=1 for every perfect matching M of G. Barrier cuts and 2-separation cuts are called ELP-cuts, which are two important types of tight cuts in matching ...covered graphs. Edmonds, Lovász and Pulleyblank proved that if a matching covered graph has a nontrivial tight cut, then it also has a nontrivial ELP-cut. Carvalho, Lucchesi, and Murty made a stronger conjecture: given any nontrivial tight cut C in a matching covered graph G, there exists a nontrivial ELP-cut D in G which does not cross C. We confirm the conjecture in this paper.
The Mu2e calorimeter consists of 1348 undoped CsI crystals coupled to two large area UV-extended Silicon Photomultipliers (SiPMs). A modular and custom SiPM layout, a 3×2 matrix of 6×6 mm2 monolithic ...SiPMs, has been developed to satisfy the Mu2e requirements. As well as ensuring the performances needed for the muon-to-electron conversion search, these photosensors have to guarantee a good reliability while operating maintenance-free in the Mu2e hostile environment: any failure can only be replaced during a long technical shut-down scheduled once a year. After testing prototypes from different vendors, we selected Hamamatsu and the final production of about 4000 pieces is now ongoing. A detailed Quality Assurance (QA) program is then mandatory to minimize the risk of an unexpected further degradation in the performances. The QA process for each photosensor includes a first visual inspection and the subsequent characterization of each of its monolithic cells by means of an automatized test station, able to measure the breakdown voltage, the gain and the dark current. For each production batch (∼300 pieces), 5 devices are exposed to a neutron fluency up to ∼1.4×1011 1 MeV (Si) eq. n/cm2; others 15 devices are undergone an accelerated aging in order to verify the Mean Time To Failure (MTTF) of the batch. A summary of the QA and the results for the firsts 4 production batches are presented in the paper.
The perfect-matching polytope of a graph G is the convex hull of the incidence vectors of all perfect matchings in G. This paper characterizes bipartite and nearly bipartite graphs whose 1-skeleton ...graphs of perfect-matching polytopes have diameter 1.
ABSTRACT
Objective The aim of the present study was to assess whether menopausal status influences the occurrence of nocturnal awakening with headache (NAH) in the female population of Sao Paulo, ...Brazil. We also examined the relationship of this complaint to sociodemographic determinants, hot flushes, sleep quality and parameters, anxiety and depressive symptoms, somnolence and fatigue according to menopausal status.
Methods The female population of the Sao Paulo Epidemiologic Sleep Study (EPISONO) (n = 576) was divided according to menopausal status (pre-, peri-, early and late menopause) based on questionnaires and hormonal blood measures. The complaint of waking up because of a headache at least once a week was assessed by the UNIFESP Sleep questionnaire. Additionally, hot flushes, sleep complaints, anxiety and depressive symptoms, somnolence and fatigue were assessed by specific questionnaires. A full-night polysomnography assessed sleep parameters.
Results The prevalence of NAH in women in the Sao Paulo population was 13.3%. Perimenopause was associated with a higher risk of having NAH (odds ratio 13.9; 95% confidence interval 4.3-45.2). More complaints of NAH were observed in obese women. All the groups with NAH showed more hot flushes, worse subjective sleep quality, more complaints of insomnia, anxiety symptoms and fatigue.
Conclusions We observed a constellation of symptoms in women according to menopausal status and NAH that included hot flushes, sleep complaints, more anxiety symptoms and fatigue. Moreover, some of these symptoms were more frequent in perimenopausal women with NAH. Therefore, we concluded that menopausal status influences NAH and the women in perimenopause presented a high risk of having this complaint.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
On Essentially 4-Edge-Connected Cubic Bricks Kothari, Nishad; De Carvalho, Marcelo H.; Lucchesi, Cláudio L. ...
The Electronic journal of combinatorics,
01/2020, Letnik:
27, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Lovász (1987) proved that every matching covered graph $G$ may be uniquely decomposed into a list of bricks (nonbipartite) and braces (bipartite); we let $b(G)$ denote the number of bricks. An edge ...$e$ is removable if $G-e$ is also matching covered; furthermore, $e$ is $b$-invariant if $b(G-e)=1$, and $e$ is quasi-$b$-invariant if $b(G-e)=2$. (Each edge of the Petersen graph is quasi-$b$-invariant.)
A brick $G$ is near-bipartite if it has a pair of edges $\{e,f\}$ so that $G-e-f$ is matching covered and bipartite; such a pair $\{e,f\}$ is a removable doubleton. (Each of $K_4$ and the triangular prism $\overline{C_6}$ has three removable doubletons.) Carvalho, Lucchesi and Murty (2002) proved a conjecture of Lovász which states that every brick, distinct from $K_4$, $\overline{C_6}$ and the Petersen graph, has a $b$-invariant edge.
A cubic graph is essentially $4$-edge-connected if it is $2$-edge-connected and if its only $3$-cuts are the trivial ones; it is well-known that each such graph is either a brick or a brace; we provide a graph-theoretical proof of this fact.
We prove that if $G$ is any essentially $4$-edge-connected cubic brick then its edge-set may be partitioned into three (possibly empty) sets: (i) edges that participate in a removable doubleton, (ii) $b$-invariant edges, and (iii) quasi-$b$-invariant edges; our Main Theorem states that if $G$ has two adjacent quasi-$b$-invariant edges, say $e_1$ and $e_2$, then either $G$ is the Petersen graph or the (near-bipartite) Cubeplex graph, or otherwise, each edge of $G$ (distinct from $e_1$ and $e_2$) is $b$-invariant. As a corollary, we deduce that each essentially $4$-edge-connected cubic non-near-bipartite brick $G$, distinct from the Petersen graph, has at least $|V(G)|$ $b$-invariant edges.
Abstract We present a case of chronic mandibular suppurative osteomyelitis after a routine extraction that required surgical and prolonged antimicrobial treatment. We also report the use of ...calcitonin as an adjunct to resolve symptoms of pain and possibly induce bony healing.
In this paper we show that, with 11 exceptions, any matching covered bipartite graph on $n$ vertices, with minimum degree greater than two, has at least $2n-4$ perfect matchings. Using this bound, ...which is the best possible, and McCuaig's theorem W. McCuaig, J. Graph Theory, 38 (2001), pp. 124--169 on brace generation, we show that any brace on $n$ vertices has at least $(n-2)^2/8$ perfect matchings. A bi-wheel on $n$ vertices has $(n-2)^2/4$ perfect matchings. We conjecture that there exists an integer $N$ such that every brace on $n\geq N$ vertices has at least $(n-2)^2/4$ perfect matchings. PUBLICATION ABSTRACT
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