Towards a time-reversal mirror for quantum systems

The reversion of the time evolution of a quantum state can be achieved by changing the sign of the Hamiltonian as in the polarization echo experiment in NMR. In this work we describe an alternative mechanism inspired by the acoustic time reversal mirror. By solving the inverse time problem in a discrete space we develop a new procedure, the perfect inverse filter. It achieves the exact time reversion in a given region by reinjecting a prescribed wave function at its periphery.Comment: 6 pages, 4 figures. Introduction modified, references added, one figure added to improve the discussio

DUET: 2D Structured and Approximately Equivariant Representations

Multiview Self-Supervised Learning (MSSL) is based on learning invariances with respect to a set of input transformations. However, invariance partially or totally removes transformation-related information from the representations, which might harm performance for specific downstream tasks that require such information. We propose 2D strUctured and EquivarianT representations (coined DUET), which are 2d representations organized in a matrix structure, and equivariant with respect to transformations acting on the input data. DUET representations maintain information about an input transformation, while remaining semantically expressive. Compared to SimCLR (Chen et al., 2020) (unstructured and invariant) and ESSL (Dangovski et al., 2022) (unstructured and equivariant), the structured and equivariant nature of DUET representations enables controlled generation with lower reconstruction error, while controllability is not possible with SimCLR or ESSL. DUET also achieves higher accuracy for several discriminative tasks, and improves transfer learning.Comment: Accepted at ICML 202

Distinct incubation for homologous in vitro spermatozoa binding on swine oocytes subjected to different storage conditions

AbstractThe sperm in vitro binding assay in homologous oocytes can be used to estimate the boar fertility potential, but its usefulness may be limited by laboratorial structure and oocytes availability. This study aimed at determining the effect of distinct methods of oocytes conditioning and incubation media for the in vitro penetration (IVP) test. Oocytes used in the IVP test were: fresh and conditioned in PBS (T1); cooled and conditioned in PBS at 5°C for 48h (T2); or stored in ovaries frozen at −20°C (T3). For each treatment, two incubation media were tested at 39°C for 6h: modified TRIS buffer medium (mTBM); or Beltsville Thawing Solution (BTS) extender. The responses of interest were: IVP and polyspermy rates; and the number of penetrating spermatozoa per oocyte. All responses observed with incubation in BTS were inferior to those observed with incubation in mTBM (P<0.0001). When incubation was done in mTBM, none of the responses differed across treatments (P>0.05). However, when incubation was in BTS, all the three responses were superior for T1 than for T2 and T3 (P<0.05). Thus, the IVP test may be conducted with ovaries either cooled or recovered from frozen ovaries with results similar to those observed with fresh oocytes, if incubation is done in mTBM

The development of the British Red Cross' psychosocial framework: 'calmer'

This paper presents the history, development and approach of the new psychosocial framework which in 2008 was adopted by the British Red Cross, and a piece of research designed to review its fitness for purpose as an educational tool. The framework CALMER is a single, overarching approach for considering and delivering psychosocial services across all of the British Red Cross. It is being included in all relevant training programmes, such as within first aid and psychosocial support and within services in emergency response, event first aid, health and social care, international tracing and message and refugee services and across human resources. The framework includes six prompts which should be followed sequentially, with guidance on facilitative behaviours within each. The research considered the levels of confidence and worry of participants on one day training programmes delivered to three different groups of personnel in three different countries. While finding support for the CALMER framework, further recommendations are made for future research

Diagnosi differenziale dei tumori parotidei: quali caratteristiche di risonanza magnetica considerare?

La finalità del nostro lavoro è di valutare le caratteristiche di risonanza magnetica (RM) tipiche dei tumori parotidei maligni e benigni. Questo studio retrospettivo si basa sulla valutazione di esami RM pre-chirurgici di 94 pazienti con tumori parotidei. I risultati istologici erano disponibili in tutti i casi; abbiamo analizzato 69 lesioni erano benigne (73%) e 25 maligne (27%): 44 adenomi pleomorfi, 18 tumori di Warthin, 7 tumori benigni di diverso istotipo, 6 carcinomi squamocellulari, 3 carcinomi ex-adenomi pleomorfi, 2 carcinomi mucoepidermoidi, 1 tumore adenoidocistico, 13 tumori maligni di diverso istotipo. Sono state valutate le seguenti caratteristiche RM: morfologia, sede, dimensioni, margini, intensità di segnale nelle sequenze T2-pesate e T1-pesate, impregnazione dopo mezzo di contrasto (mdc), intensità di segnale della porzione cistica, presenza o assenza di una capsula, diffusione perineurale, pattern di crescita extraghiandolare e linfoadenopatie laterocervicali. È stata effettuata un’analisi statistica per identificare le caratteristiche RM più indicative di malignità e per definire l’aspetto tipico degli istotipi più comuni. I parametri significativamente predittivi di malignità sono risultati i margini mal-definiti (p < 0,001), le linfoadenopatie (p < 0,001) ed il pattern di crescita infiltrativo (p < 0,001). Le caratteristiche tipiche dell’adenoma pleomorfo sono risultate l’iperintensità di segnale nelle immagini T2-pesate (p = 0,02), l’intensa impregnazione dopo mdc (p < 0,001) ed i margini lobulati (p = 0,04). Le caratteristiche tipiche del tumore di Warthin sono risultate le componenti iperintense nelle immagini T1-pesate (p < 0,001), la localizzazione nel processo parotideo inferiore (p < 0,001) e l’impregnazione post-contrastografica lieve/incompleta (p = 0,01). L’intensità di segnale nelle immagini T1-pesate e T2- pesate e l’impregnazione post-contrastografica si sono rivelate utili nella diagnosi differenziale tra adenoma pleomorfo e tumore di Warthin

Despite lost contractility, a sub-population of rat muscle fibers maintains an assessable excitation-contraction coupling mechanism after long-standing denervation

J Neuropathol Exp Neurol. 2009 Dec;68(12):1256-68. A subpopulation of rat muscle fibers maintains an assessable excitation-contraction coupling mechanism after long-standing denervation despite lost contractility. Squecco R, Carraro U, Kern H, Pond A, Adami N, Biral D, Vindigni V, Boncompagni S, Pietrangelo T, Bosco G, Fanò G, Marini M, Abruzzo PM, Germinario E, Danieli-Betto D, Protasi F, Francini F, Zampieri S. Source Interuniversitary Institute of Myology, Chieti, Italy. Abstract To define the time course and potential effects of electrical stimulation on permanently denervated muscle, we evaluated excitation-contraction coupling (ECC) of rat leg muscles during progression to long-term denervation by ultrastructural analysis, specific binding to dihydropyridine receptors, ryanodine receptor 1 (RYR-1), Ca channels and extrusion Ca pumps, gene transcription and translation of Ca-handling proteins, and in vitro mechanical properties and electrophysiological analyses of sarcolemmal passive properties and L-type Ca current (ICa) parameters. We found that in response to long-term denervation: 1) isolated muscle that is unable to twitch in vitro by electrical stimulation has very small myofibers but may show a slow caffeine contracture; 2) only roughly half of the muscle fibers with "voltage-dependent Ca channel activity" are able to contract; 3) the ECC mechanisms are still present and, in part, functional; 4)ECC-related gene expression is upregulated; and 5) at any time point, there are muscle fibers that are more resistant than others to denervation atrophy and disorganization of the ECC apparatus. These results support the hypothesis that prolonged "resting" [Ca] may drive progression of muscle atrophy to degeneration and that electrical stimulation-induced [Ca] modulation may mimic the lost nerve influence, playing a key role in modifying the gene expression of denervated muscle. Hence, these data provide a potential molecular explanation for the muscle recovery that occurs in response to rehabilitation strategies developed based on empirical clinical observations. PMID: 19915489 [PubMed - indexed for MEDLINE

FIP200 claw domain binding to p62 promotes autophagosome formation at ubiquitin condensates

The autophagy cargo receptor p62 facilitates the condensation of misfolded, ubiquitin-positive proteins and their degradation by autophagy, but the molecular mechanism of p62 signaling to the core autophagy machinery is unclear. Here, we show that disordered residues 326-380 of p62 directly interact with the C-terminal region (CTR) of FIP200. Crystal structure determination shows that the FIP200 CTR contains a dimeric globular domain that we designated the "Claw" for its shape. The interaction of p62 with FIP200 is mediated by a positively charged pocket in the Claw, enhanced by p62 phosphorylation, mutually exclusive with the binding of p62 to LC3B, and it promotes degradation of ubiquitinated cargo by autophagy. Furthermore, the recruitment of the FIP200 CTR slows the phase separation of ubiquitinated proteins by p62 in a reconstituted system. Our data provide the molecular basis for a crosstalk between cargo condensation and autophagosome formation