6,927 research outputs found
Surviving on Mars: test with LISA simulator
We present the biological results of some experiments performed in the Padua
simulators of planetary environments, named LISA, used to study the limit of
bacterial life on the planet Mars. The survival of Bacillus strains for some
hours in Martian environment is shortly discussed.Comment: To be published on Highlights of Astronomy, Volume 15 XXVIIth IAU
General Assembly, August 2009 Ian F Corbett, ed. 2 pages, 1 figur
Smooth optimal control with Floquet theory
This paper describes an approach to construct temporally shaped control
pulses that drive a quantum system towards desired properties. A
parametrization in terms of periodic functions with pre-defined frequencies
permits to realize a smooth, typically simple shape of the pulses; their
optimization can be performed based on a variational analysis with Floquet
theory. As we show with selected specific examples, this approach permits to
control the dynamics of interacting spins, such that gate operations and
entanglement dynamics can be implemented with very high accuracy
On the phase diagram of the Higgs SU(2) model
The Higgs SU(2) model with fixed Higgs length is usually believed to have two
different phases at high gauge coupling (\beta), separated by a line of first
order transitions but not distinuguished by any typical symmetry associated
with a local order parameter, as first proved by Fradkin and Shenker. We show
that in regions of the parameter space where it is usually supposed to be a
first order phase transition only a smooth crossover is in fact present.Comment: 6 pages, 6 figures. Talk presented at The XXVI International
Symposium on Lattice Field Theory, July 14 - 19, 2008 - Williamsburg,
Virginia, US
Degrees of controllability for quantum systems and applications to atomic systems
Precise definitions for different degrees of controllability for quantum
systems are given, and necessary and sufficient conditions are discussed. The
results are applied to determine the degree of controllability for various
atomic systems with degenerate energy levels and transition frequencies.Comment: 20 pages, IoP LaTeX, revised and expanded versio
LISA: Mars and the limits of life
We describe the results of the first tests made on LISA, a simulator of
planetary environments designed and built in Padua, dedicated to the study of
the limit of bacterial life on the planet Mars. Tests on the cryogenic circuit,
on the UV illumination and on bacterial coltures at room temperature that shall
be used as references are described.Comment: 4 pages, 3 figures. Mem. SAIt, in pres
Post-thaw survival and acrosome integrity of spermatozoa of Leccese rams frozen in different seasons with a milk-egg yolk extender
The influence of the period of semen collection on post-thawing survival, motility and acrosome integrity of spermatozoain Leccese rams was studied throughout an entire year. The year was divided into the seasons: winter and spring (firstsemester) and summer and autumn (second semester). Semen from 5 adult rams was collected every two weeks by artificialvagina and frozen according to a freezing system based on milk-lactose egg yolk to constitute semen doses of 400x 106 spermatozoa. At thawing, survival and acrosomal status of cells were assessed and the motility of the sperm andtheir kinetic rating (scale 0 to 5 score) were determined at thawing (0 h), and after 1 and 3 h incubation (37° C).Semen collected during the first semester (winter – spring) of the year showed the highest (P<0.01) proportion of postthawlive spermatozoa, with the maximum value in winter (P<0.01), and the best acrosomal status of spermatozoa, consideredas both total proportion of spermatozoa with acrosome break down and spermatozoa without acrosomes.Acrosome integrity was positively correlated (r = 0.32; P<0.01) with post-thaw sperm viability.Motility of spermatozoa at thawing was not influenced by the period of semen collection. However, after 3 h incubationsperm motility was higher (P<0.01) during the first semester of the year, without a difference between winter and spring.A marked individual ram effect was found on freezability of semen.The results provide evidence that the period of semen collection can influence freezability of spermatozoa in Lecceserams. The best characteristics of spermatozoa were observed during the first semester of the year, corresponding to thesexual hypoactivity season for this breed
Influence of milking number and frequency on milk production in Martina Franca breed asses
Two experiments were carried out in Martina Franca asses in order to study milk yield and udder healthy conditions in relation to daily milking number and frequency. Experiment I - A total of 15 asses were subdivided into three groups (N.5) corresponding to: one milking per day, after a 3 hour interval from foal separation by dams (Group A); three milkings per day with 3 hour frequency (Group B); three milkings per day with 2 hour frequency (Group 3M). Experiment II - Evaluation was made of the effect of a schedule of 6 milkings per day with frequency of 2 hours on milk yield (Group 6M; N. 5), compared to Group 3M). Healthy udder conditions in relation to the number of milking per day was monitored in 3M) and 6M) Groups, by somatic cell count. Average yield per milking was highest (P<0.01) following 3 rather 1 milkings per day and with milking frequency of 3 hours rather than 2 hours (P<0.01). A schedule of six milkings per day did not improve mean milk yield and determined an increase in somatic cell count compared to 3 daily milkings regimen (63.2 vs 17.5 x 1000/mL; P<0.05)
Aqueye+: a new ultrafast single photon counter for optical high time resolution astrophysics
Aqueye+ is a new ultrafast optical single photon counter, based on single
photon avalanche photodiodes (SPAD) and a 4-fold split-pupil concept. It is a
completely revisited version of its predecessor, Aqueye, successfully mounted
at the 182 cm Copernicus telescope in Asiago. Here we will present the new
technological features implemented on Aqueye+, namely a state of the art timing
system, a dedicated and optimized optical train, a high sensitivity and high
frame rate field camera and remote control, which will give Aqueye plus much
superior performances with respect to its predecessor, unparalleled by any
other existing fast photometer. The instrument will host also an optical
vorticity module to achieve high performance astronomical coronography and a
real time acquisition of atmospheric seeing unit. The present paper describes
the instrument and its first performances.Comment: Proceedings of the SPIE, Volume 9504, id. 95040C 14 pp. (2015
Il sistema di monitoraggio della rete sismica realizzato presso l'Osservatorio di Gibilmanna
Tutte le stazioni gestite dall’Osservatorio di Gibilmanna partecipano ai processi di localizzazione degli eventi sismici in esecuzione presso la sala sismica del Centro Nazionale Terremoti. La mancanza di dati
provenienti da alcune stazioni, a causa di guasti alla strumentazione o a causa di interruzioni delle reti di trasmissione dati, può degradare la precisione della stima dei parametri ipocentrali degli eventi
sismici localizzati. Da ciò si desume quanto sia importante garantire la massima efficienza della rete ed un
rapido intervento tecnico per la risoluzione dei guasti. A tal fine, presso l’Osservatorio di Gibilmanna, è stato
realizzato un sistema di monitoraggio delle stazioni GAIA2 e dei componenti di rete di proprietà dell’INGV che permette:
1. l’automatica ed immediata segnalazione del guasto tramite e-mail;
2. l’individuazione dei componenti di rete guasti;
3. una prima diagnosi relativa al guasto rilevato, grazie allo storico dei parametri monitorati;
4. una risoluzione automatica del guasto nei casi in cui sia sufficiente un reset del software di acquisizione dei segnali sismici o un soft-reset dell’acquisitore.
Il sistema di monitoraggio è stato realizzato mediante l’utilizzo di due applicazioni: i) The Dude,
software free della MikroTik, che effettua il monitoraggio della presenza dei componenti di rete mediante
ping e verifica l’apertura di porte TCP/IP fondamentali come quella aperta dal server Seedlink; ii) Zabbix, software open source che permette il monitoraggio in real-time di diversi parametri di stato dei nodi della
rete mediante protocollo SNMP (Simple Network Management Protocol).
Sfruttando alcune funzionalità di Zabbix, gli autori del presente Rapporto Tecnico hanno sviluppato una soluzione sistemistica che permette il riavvio dell’applicativo che sulle GAIA2 acquisisce i segnali sismici, nel caso in cui questo risulti bloccato. Per permettere l’interfacciamento tra Zabbix e le GAIA2, infatti, sono stati sviluppati degli script da installare sul server Zabbix ed a bordo delle GAIA2, grazie ai quali, congiuntamente con alcune configurazioni del server SSH sulla GAIA2, il server Zabbix è in grado di accedere in automatico via SSH sulle GAIA2 e di eseguire alcuni comandi per la risoluzione del problema riscontrato in fase di monitoraggio.
Il sistema implementato, ha permesso di ridurre i tempi di interruzione nell’invio dei segnali sismici. Inoltre ha reso possibile una migliore gestione dei guasti,
grazie all’immediata notifica del problema e all’individuazione della tipologia di guasto
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