1,354 research outputs found
39-K Bose-Einstein condensate with tunable interactions
We produce a Bose-Einstein condensate of 39-K atoms. Condensation of this
species with naturally small and negative scattering length is achieved by a
combination of sympathetic cooling with 87-Rb and direct evaporation,
exploiting the magnetic tuning of both inter- and intra-species interactions at
Feshbach resonances. We explore tunability of the self-interactions by studying
the expansion and the stability of the condensate. We find that a 39-K
condensate is interesting for future experiments requiring a weakly interacting
Bose gas.Comment: 5 page
Collisional and molecular spectroscopy in an ultracold Bose-Bose mixture
The route toward a Bose-Einstein condensate of dipolar molecules requires the
ability to efficiently associate dimers of different chemical species and
transfer them to the stable rovibrational ground state. Here, we report on
recent spectroscopic measurements of two weakly bound molecular levels and
newly observed narrow d-wave Feshbach resonances. The data are used to improve
the collisional model for the Bose-Bose mixture 41K87Rb, among the most
promising candidates to create a molecular dipolar BEC.Comment: 13 pages, 3 figure
Feshbach resonances in ultracold K(39)
We discover several magnetic Feshbach resonances in collisions of ultracold
K(39) atoms, by studying atom losses and molecule formation. Accurate
determination of the magnetic-field resonance locations allows us to optimize a
quantum collision model for potassium isotopes. We employ the model to predict
the magnetic-field dependence of scattering lengths and of near-threshold
molecular levels. Our findings will be useful to plan future experiments on
ultracold potassium atoms and molecules.Comment: 7 pages, 6 figure
Effect of affective priming on prosocial orientation through mobile application: Differences between digital immigrants and natives
Digital revolution has drastically changed people’s lives in the last three decades inspiring scholars to deepen the role of technologies in thinking and information processing (Baranyi et al., 2015). Prensky (2001) has developed the notion of digital generation, differentiating between natives and immigrants. Digital natives are characterised by their highly automatic and quick response in hyper-textual environment. Digital immigrants are characterised by their main focus on textual elements and a greater proneness to reflection. The main goal of the present research is to investigate the effect of affective priming on prosocial orientation in natives and immigrants by using a mobile application. A quasi-experimental study has been conducted to test whether and how the manipulation of the priming, through positively and negatively connoted images, influences prosocial orientation. The results attested that negative affective priming elicited by app influences negatively prosocial orientation, while positive affective priming influences it positively prosocial orientation. However, this effect is true mainly for digital natives. Overall, findings underline the relevance of taking into account the effects of affective priming in technological environment, especially in the case of digital natives
Physicochemical properties of mixed micellar aggregates containing CCK peptides and Gd complexes designed as tumor specific contrast agents in MRI
New amphiphilic molecules containing a bioactive peptide or a claw moiety have been prepared
in order to obtain mixed micelles as target-specific contrast agents in magnetic resonance imaging. The
first molecule, C18H37CONH(AdOO)2-G-CCK8 (C18CCK8), contains a C18 hydrophobic moiety bound to
the C-terminal cholecystokinin octapeptide amide (CCK 26-33 or CCK8). The second amphiphilic
compound, C18H37CONHLys(DTPAGlu)CONH2 (C18DTPAGlu) or its gadolinium complex, (C18DTPAGlu-
(Gd)), contains the same C18 hydrophobic moiety bound, through a lysine residue, to the DTPAGlu chelating
agent. The mixed aggregates as well as the pure C18DTPAGlu aggregate, in the presence and absence
of Gd, have been fully characterized by surface tension measurements, FT-PGSE-NMR, fluorescence
quenching, and small-angle neutron scattering measurements. The structural characterization of the mixed
aggregates C18DTPAGlu(Gd)-C18CCK8 indicates a spherical arrangement of the micelles with an external
shell of 21 Ã… and an inner core of 20 Ã…. Both the DTPAGlu(Gd) complexes and the CCK8 peptides
point toward the external surface. The measured values for relaxivity in saline medium at 20 MHz proton
Larmor frequency and 25 °C are 18.7 mM-1 s-1. These values show a large enhancement in comparison
with the isolated DTPAGlu(Gd) complex
Bragg interferometers with interacting Bose-Einstein condensates
In search of non-classical correlations between momentum components of a Bose-Einstein condensate (BEC), we have investigated atom interferometers of trapped and free-falling BEC, obtaining a quantitative description of the spacing of interference fringes observed at output ports
Effect of interactions in the interference pattern of Bose Einstein condensates
Understanding the effect of interactions in the phase evolution of expanding
atomic Bose Einstein condensates is fundamental to describe the basic
phenomenon of matter wave interference. Many theoretical and experimental works
tackled this problem, always with the implicit assumption that the mutual
interaction between two expanding condensates rigidly modifies the phase
evolution through an effective force. In this paper, we present a combined
experimental and theoretical investigation of the interference profile of
expanding Rb condensates, with a specific focus on the effect of
interactions. We come to the different conclusion that the mutual interaction
produces local modifications of the condensate phase only in the region where
the wavepackets overlap.Comment: 10 pages, 14 figures; replacing previous version where Eq. 2 was
missin
Fast and Sensitive Detection of Soil-Borne Cereal Mosaic Virus in Leaf Crude Extract of Durum Wheat
Soil-borne cereal mosaic virus (SBCMV) is a furovirus with rigid rod-shaped particles containing an ssRNA genome, transmitted by Polymyxa graminis Led., a plasmodiophorid that can persist in soil for up to 20 years. SBCMV was reported on common and durum wheat and it can cause yield losses of up to 70%. Detection protocols currently available are costly and time-consuming (real-time PCR) or have limited sensitivity (ELISA). To facilitate an efficient investigation of the real dispersal of SBCMV, it is necessary to develop a new detection tool with the following characteristics: no extraction steps, very fast results, and high sensitivity to allow pooling of a large number of samples. In the present work, we have developed a reverse transcription loop-mediated isothermal amplification (RT-LAMP) protocol with such characteristics, and we have compared it with real-time PCR. Our results show that the sensitivity of LAMP and real-time PCR on cDNA and RT-LAMP on crude extracts are comparable, with the obvious advantage that RT-LAMP produces results in minutes rather than hours. This paves the way for extensive field surveys, leading to a better knowledge of the impact of this virus on wheat health and yield
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