From the Jordan product to Riemannian geometries on classical and quantum states

The Jordan product on the self-adjoint part of a finite-dimensional $C^{*}$-algebra $\mathscr{A}$ is shown to give rise to Riemannian metric tensors on suitable manifolds of states on $\mathscr{A}$, and the covariant derivative, the geodesics, the Riemann tensor, and the sectional curvature of all these metric tensors are explicitly computed. In particular, it is proved that the Fisher--Rao metric tensor is recovered in the Abelian case, that the Fubini--Study metric tensor is recovered when we consider pure states on the algebra $\mathcal{B}(\mathcal{H})$ of linear operators on a finite-dimensional Hilbert space $\mathcal{H}$, and that the Bures--Helstrom metric tensors is recovered when we consider faithful states on $\mathcal{B}(\mathcal{H})$. Moreover, an alternative derivation of these Riemannian metric tensors in terms of the GNS construction associated to a state is presented. In the case of pure and faithful states on $\mathcal{B}(\mathcal{H})$, this alternative geometrical description clarifies the analogy between the Fubini--Study and the Bures--Helstrom metric tensor.Comment: 32 pages. Minor improvements. References added. Comments are welcome

The perfect crime? : CCSVI not leaving a trace in MS

Background: Multiple sclerosis (MS) is a chronic, inflammatory demyelinating disease of the central nervous system, believed to be triggered by an autoimmune reaction to myelin. Recently, a fundamentally different pathomechanism termed ‘chronic cerebrospinal venous insufficiency’ (CCSVI) was proposed, provoking significant attention in the media and scientific community. Methods: Twenty MS patients (mean age 42.2±13.3 years; median Extended Disability Status Scale 3.0, range 0–6.5) were compared with 20 healthy controls. Extra- and intracranial venous flow direction was assessed by colour-coded duplex sonography, and extracranial venous cross-sectional area (VCSA) of the internal jugular and vertebral veins (IJV/VV) was measured in B-mode to assess the five previously proposed CCSVI criteria. IJV-VCSA≤0.3 cm2 indicated ‘stenosis,’ and IJV-VCSA decrease from supine to upright position ‘reverted postural control.’ The sonographer, data analyser and statistician were blinded to the patient/control status of the participants. Results: No participant showed retrograde flow of cervical or intracranial veins. IJV-VCSA≤0.3 cm2 was found in 13 MS patients versus 16 controls (p=0.48). A decrease in IJV-VCSA from supine to upright position was observed in all participants, but this denotes a physiological finding. No MS patient and one control had undetectable IJV flow despite deep inspiration (p=0.49). Only one healthy control and no MS patients fulfilled at least two criteria for CCSVI. Conclusions: This triple-blinded extra- and transcranial duplex sonographic assessment of cervical and cerebral veins does not provide supportive evidence for the presence of CCSVI in MS patients. The findings cast serious doubt on the concept of CCSVI in MS

Autorsuse tuvastamine sõnavaralise ja märgipõhise tekstianalüüsi meetoditega

Inteneti lai levik tänapäeval on olulise probleemina tõstatanud tekstide autorsuse küsimuse. Mõningatel juhtudel on tingimata vaja kirjutaja isik kindlaks teha. Autorsuse tuvastamise meetodid annavad võimaluse võrdlemisi täpselt määrata kahtluse all oleva teksti autori. Käesolevas bakalaureusetöös uuriti autorsuse tuvastamist sõnavaraliste ja märgip õhiste tekstianalüüsi meetoditega. Tehtud uurimuse ning eksperimendi tulemuste põhjal võib järeldada, et sõnavarap õhise ja märgipõhise tekstianalüüsi meetoditega on edukalt võimalik tundmatu teksti autorit tuvastada. Seda näitas väga hästi tabelis 9 välja toodud Vootele Päi kahe arvamusartikli võrdlus ning vastava tabeli analüüs peatükis 5.1, mille tulemuseks oli kahe teksti aritmeetilise keskmise erinevus ligikaudu 3% ning hii-ruut-statistiku väärtus oli üle viie korra väiksem 95% tõenäosuse juures ja 6 vabadusastmete arvuga, mis näitab kui sarnased need kaks artiklit omavahel olid. Samamoodi näitasid eksperimendi tulemused ka vastupidist ehk kahe teksti erinevust. Tabelis 13 ning peatükis 5.5 esitatud tabelite analüüsi põhjal on näha nii aritmeetiliselt kui ka kumulatiivselt kahe teksti erinevust ning ka hii-ruut-statistik kinnitab seda. Hii-ruut-statistiku väärtus oli mõlema võrdluse puhul lävendist kõrgem. Selline erinevus viitab järjekordselt sellele, et kasutusel olev mudel suudab kahte autorit omavahel eristada. Tekstide erinevuse hindamiseks oli kasutusel kolm erinevat hindamisevalemit. Kõige paremini sobis hii-ruut statistik, sest see näitas kõige täpsemalt kahe teksti statistilist erinevust seitsme parameetri põhjal. Veel oli kasutusel aritmeetiline keskmine ja kumulatiivne hindamine, millele vastavalt leiti kas seitsme parameetri aritmeetiline keskmise või summa. Sõnavaralised ja märgipõhised tekstianalüüsi meetodid on vägagi efektiivsed. Need meetodid näitavad, et tõesti on igal autoril oma nii-öelda käekiri, mis on talle tahes-tahtmata omane. Esmane uurimus autorite tuvastamisel, kasutades kindlaid mudeleid, oli äärmiselt edukas, kuid siiski on vajalikud edaspidised laialdasemad uuringud. Järgmise etapina olekski plaanis teha ulatuslik uuring, mis tooks välja selle programmi võimalikud piirangud, ning vajadusel kohandada mudelit ka tulevikus kasutatavate suuremate andmestike jaoks

Differential geometric aspects of parametric estimation theory for states on finite-dimensional C*-algebras

A geometrical formulation of estimation theory for finite-dimensional $C^{\star}$-algebras is presented. This formulation allows to deal with the classical and quantum case in a single, unifying mathematical framework. The derivation of the Cramer-Rao and Helstrom bounds for parametric statistical models with discrete and finite outcome spaces is presented.Comment: 33 pages. Minor improvements. References added. Comments are welcome

Somatotopy of placebo analgesia is independent of spatial attention

Placebo analgesia is being increasingly appraised as an effective support of pharmacological and surgical treatments of pain. The understanding of its neurobiological and psychological basis is therefore of high clinical relevance. It has been shown that placebo analgesia is somatotopically organized and relies on endogenous opioids. However, it is not clear whether temporal fluctuations of cue-dependent spatial attention account for the site specificity of placebo analgesia or whether a somatotopic placebo effect is possible without an attentional focus on the respective location. To address this issue we induced placebo expectations for one specific foot in healthy subjects, the other foot serving as a control location. The feet were stimulated in random order by painful laser stimuli. Half of the pulses were cued for stimulus location, whereas in the other half of trials the subjects were naïve about the location. We found that about half of the subjects exhibited a somatotopic placebo effect that was statistically independent of the spatial cue. We suggest that, after the induction of an initial expectation, placebo analgesia is spatially specific but does not necessarily depend on momentary fluctuations of spatial attention. This result rather suggests that the somatotopy of placebo analgesia relies on the creation of spatially guided expectations or conditioning, but can be maintained without ongoing monitoring of the affected body part

Comprehensive machine data acquisition through intelligent parameter identification and assignment

In today’s highly competitive manufacturing environment, process data monitoring continues to be of high priority, but often relies on modern communication interfaces being provided by PLC manufacturers. This paper proposes an alternative approach in which data is acquired automatically from various PLC models through available interfaces. Multiple Machine Learning algorithms are incorporated to identify machine parameters, which are then assigned to appropriate machine information models. All functionalities can be provided by a dedicated hardware module or as software modules on IPCs. The proposed approach can be integrated into existing Industry 4.0 efforts to accelerate digitalization in challenging environments

A coadjoint orbit-like construction for Jordan superalgebras

We investigate the canonical pseudo-Riemannian metrics associated with Jordan-analogues of the coadjoint orbits for pseudo-Euclidean Jordan superalgebras.Comment: 20 pages, 1 figur

Very Late Stent Thrombosis 42 Months after Implantation of Sirolimus-Eluting Stent and Discontinuation of Antiplatelet Therapy

Although safety profiles of sirolimus-eluting stents do not seem to differ in short-to-medium term from those of bare-metal stents, late stent thrombosis after deployment of drug-eluting stents has emerged as a potential safety concern in the era of high-pressure stent implantation. Here, we describe the case of a patient with acute myocardial infarction due to stent thrombosis of a sirolimus-eluting stent 42 months after stent deployment and 5 weeks after discontinuation of aspirin treatment. To the best of our knowledge, this is one of the most delayed cases of sirolimus-eluting stent thrombosis described so far. The case emphasizes the potential risk that late stent thrombosis can unpredictably occur at any time point after drug-eluting stent deployment