PMN J1838-3427: A new gravitationally lensed quasar

We report the discovery of a new double-image quasar that was found during a search for gravitational lenses in the southern sky. Radio source PMN J1838-3427 is composed of two flat-spectrum components with separation 1", flux density ratio 14:1 and matching spectral indices, in VLA and VLBA images. Ground-based BRI images show the optical counterpart (total I=18.6) is also double with the same separation and position angle as the radio components. An HST/WFPC2 image reveals the lens galaxy. The optical flux ratio (27:1) is higher than the radio value probably due to differential extinction of the components by the lens galaxy. An optical spectrum of the bright component contains quasar emission lines at z=2.78 and several absorption features, including prominent Ly-alpha absorption. The lens galaxy redshift could not be measured but is estimated to be z=0.36 +/- 0.08. The image configuration is consistent with the simplest plausible models for the lens potential. The flat radio spectrum and observed variability of PMN J1838-3427 suggest the time delay between flux variations of the components is measurable, and could thus provide an independent measurement of H_0.Comment: 23 pages, incl. 6 figures, to appear in A.J.; replaced with accepted version; minor changes to text, improved figure

Quantifying Properties of Photospheric Magnetic Cancellations in the Quiet Sun Internetwork

We analyzed spectropolarimetric data from the Swedish 1-meter Solar Telescope to investigate physical properties of small-scale magnetic cancellations in the quiet Sun photosphere. Specifically, we looked at the full Stokes polarization profiles along the Fe I 557.6 nm and of the Fe I 630.1 nm lines measured by CRisp Imaging SpectroPolarimeter (CRISP) to study temporal evolution of the line-of-sight (LOS) magnetic field during 42.5 minutes of quiet Sun evolution. From this magnetogram sequence, we visually identified 38 cancellation events. We then used Yet Another Feature Tracking Algorithm (YAFTA) to characterize physical properties of these magnetic cancellations. We found on average $1.6\times10^{16}$ Mx of magnetic flux cancelled in each event with an average cancellation rate of $3.8\times10^{14}$ Mx s$^{-1}$. The derived cancelled flux is associated with strong downflows, with an average speed of $V_\mathrm{LOS}\approx1.1$ km s$^{-1}$. Our results show that the average lifetime of each event is $9.2$ minutes with an average $44.8\%$ of initial magnetic flux being cancelled. Our estimates of magnetic fluxes provide a lower limit since studied magnetic cancellation events have magnetic field values that are very close to the instrument noise level. We observed no horizontal magnetic fields at the cancellation sites and therefore can not conclude whether the events are associated structures that could cause magnetic reconnection.Comment: 19 pages, 18 figures, 2 tables, accepted into ApJ on 06/08/202

Anti-leukemia activity of alloreactive NK cells in KIR ligand-mismatched haploidentical HSCT for pediatric patients: evaluation of the functional role of activating KIR and redefinition of inhibitory KIR specificity.

none15We analyzed 21 children with leukemia receiving haploidentical hematopoietic stem cell transplantation (haplo-HSCT) from killer immunoglobulin (Ig)-like receptors (KIR) ligand-mismatched donors. We showed that, in most transplantation patients, variable proportions of donor-derived alloreactive natural killer (NK) cells displaying anti-leukemia activity were generated and maintained even late after transplantation. This was assessed through analysis of donor KIR genotype, as well as through phenotypic and functional analyses of NK cells, both at the polyclonal and clonal level. Donor-derived KIR2DL1(+) NK cells isolated from the recipient displayed the expected capability of selectively killing C1/C1 target cells, including patient leukemia blasts. Differently, KIR2DL2/3(+) NK cells displayed poor alloreactivity against leukemia cells carrying human leukocyte antigen (HLA) alleles belonging to C2 group. Unexpectedly, this was due to recognition of C2 by KIR2DL2/3, as revealed by receptor blocking experiments and by binding assays of soluble KIR to HLA-C transfectants. Remarkably, however, C2/C2 leukemia blasts were killed by KIR2DL2/3(+) (or by NKG2A(+)) NK cells that coexpressed KIR2DS1. This could be explained by the ability of KIR2DS1 to directly recognize C2 on leukemia cells. A role of the KIR2DS2 activating receptor in leukemia cell lysis could not be demonstrated. Altogether, these results may have important clinical implications for the selection of optimal donors for haplo-HSCT.openPENDE D; MARCENARO S; FALCO M; MARTINI S; BERNARDO ME; MONTAGNA D; ROMEO E; COGNET C; MARTINETTI M; MACCARIO R; MINGARI MC; VIVIER E; MORETTA L; LOCATELLI F; MORETTA A.Pende, D; Marcenaro, S; Falco, M; Martini, S; Bernardo, Me; Montagna, Daniela; Romeo, E; Cognet, C; Martinetti, M; Maccario, R; Mingari, Mc; Vivier, E; Moretta, L; Locatelli, Franco; Moretta, A

Optothermal nonlinearity of silica aerogel

The authors acknowledge support from EPSRC (EP/J004200/1), the Templeton Foundation (grant number 58277) and the ERC project VANGUARD (grant number 664782).We report on the characterization of silica aerogel thermal optical nonlinearity, obtained by z-scan technique. The results show that typical Silica Aerogels have nonlinear optical coefficient similar to that of glass (≃ 10-12m2/W), with negligible optical nonlinear absorption. The nonlinear coefficient can be increased to values in the range of 10-10m2/W by embedding an absorbing dye in the Aerogel. This value is one order of magnitude higher than that observed in the pure dye and in typical highly nonlinear materials like liquid crystals.PostprintPeer reviewe

Rapporto tecnico sulla valutazione della biomassa ittioplanctonica mediante l'utilizzo del Multi Plankton Sampler (MPS)

Il piano di campionamento della campagna oceanografica BANSIC'14, condotta a bordo della N/O "URANIA" dal 22 Luglio al 9 Agosto 2014, lungo transetti sotto costa e a largo delle coste meridionali della Sicilia, ha avuto l’obiettivo generale dello studio delle relazioni tra le strutture oceanografiche a mesoscala (vortici verticali ed orizzontali, upwelling, etc.) e le strutture spaziali dei fenomeni biologici relativi ai primi anelli della catena trofica (zooplancton, distribuzione e abbondanza di larve di piccoli pelagici e grandi pelagici) (vedi Rapporto finale BANSIC 2014) per la stima dell’abbondanza dello stock riproduttore. E' una campagna di ricerca nell'ambito del WP3 del progetto SSD-Pesca, finanziato dal MIUR su fondi MISE, a supporto della pesca italiana nelle Regioni Obiettivo 1 e del progetto RITMARE (SP2_WP4_AZ2_UO04). Il campionamento ittioplanctonico è inserito anche nel piano di lavoro del progetto regionale MIPAF-FAO “MedSudMed” (“Assessment and Monitoring of the Fishery Resources and the Ecosystems in the Straits of Sicily”). Il campionamento dell’ittioplancton, durante questa campagna, oltre ai metodi tradizionali quali le reti di tipo Bongo, ha visto l'utilizzo del Multi Plankton Sampler (MPS) MultiNet. I campionatori ittioplanctonici hanno lo scopo di prelevare porzioni di mesozooplancton da un massimo di 100 m fino alla superficie, in quanto le uova di pesci pelagici possiedono una galleggiabilità tale che nonostante le turbolenze superficiali dell’acqua, un campionamento entro i primi metri restituisce un dato affidabile della distribuzione anche se alcune uova possono trovarsi a maggiore profondità (Ahlstrom, 1959). Il campionatore MPS consente, a differenza di altri strumenti, di prelevare la frazione di zooplancton d'interesse con diverse modalità di campionamento: orizzontale, verticale e obliquo e, allo stesso tempo, permette di campionare a differenti quote di profondità. Le informazioni così ottenute sono state utilizzate per valutare la variazione della biomassa ittioplanctonica, l'abbondanza e la composizione delle specie lungo gli strati della colonna d'acqua anche in relazione alle componenti oceanografiche. Grazie all'utilizzo di questo strumento è possibile validare e verificare alcune informazioni e acquisirne delle nuove sull’ecologia delle specie larvali e sul mesozooplancton, sul modo in cui queste si distribuiscono lungo la colonna d'acqua e sulle interazioni intra ed interspecifiche legate anche a fattori oceanografici. Ciò consente di ottenere maggiori informazioni e contribuire al miglioramento della comprensione della biologia e dell'ecologia delle specie rinvenute e, nel contempo, approfondire e migliorare le conoscenze sugli stadi di sviluppo di uova di specie ittiche che allo stadio embrionale sono ancora poco conosciuti

Imported arboviral infections in Italy, July 2014-October 2015: A National Reference Laboratory report

BACKGROUND: Imported cases of infections due to Dengue (DENV) and Chikungunya (CHIKV) viruses and, more recently, Zika virus (ZIKV) are commonly reported among travelers returning from endemic regions. In areas where potentially competent vectors are present, the risk of autochthonous transmission of these vector-borne pathogens is relatively high. Laboratory surveillance is crucial to rapidly detect imported cases in order to reduce the risk of transmission. This study describes the laboratory activity performed by the National Reference Laboratory for Arboviruses (NRLA) at the Italian National Institute of Health in the period from July 2014 to October 2015. METHODS: Samples from 180 patients visited/hospitalized with a suspected DENV/CHIKV/ZIKV infection were sent to the NRLA from several Italian Hospitals and from Regional Reference Laboratories for Arboviruses, in agreement with the National Plan on human surveillance of vector-borne diseases. Both serological (ELISA IgM test and Plaque Reduction Neutralization Test-PRNT) and molecular assays (Real Time PCR tests, RT-PCR plus nested PCR and sequencing of positive samples) were performed. RESULTS: DENV infection was the most frequently diagnosed (80 confirmed/probable cases), and all four genotypes were detected. However, an increase in imported CHIKV cases (41 confirmed/probable cases) was observed, along with the detection of the first ZIKV cases (4 confirmed cases), as a consequence of the recent spread of both CHIKV and ZIKV in the Americas. CONCLUSIONS: Main diagnostic issues highlighted in our study are sensitivity limitations of molecular tests, and the importance of PRNT to confirm serological results for differential diagnosis of Arboviruses. The continuous evaluation of diagnostic strategy, and the implementation of laboratories networks involved in surveillance activities is essential to ensure correct diagnosis, and to improve the preparedness for a rapid and proper identification of viral threats

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London