295 research outputs found
Adolescentsâ daily face-to-face and computer-mediated communication: Associations with autonomy and closeness to parents and friends
The amount of time adolescents spend communicating via digital technologies such as smartphones has led to concerns that computer-mediated communication (CMC) is displacing face-to-face (FtF) interactions and disrupting social development. Although many studies have examined CMC in adolescents' relationships with friends, few studies have examined the role of CMC in adolescents' renegotiation of closeness and autonomy with parents. To examine this issue, we administered an online daily diary with 169 U.S. adolescents to estimate the time they spend in CMC and FtF interactions and the number of texts they exchange with friends and parents. On the last day of the survey, we asked adolescents about their emotional closeness to friends and parents and their balance of closeness and volition with parents. Overall, we found more evidence for social stimulation than displacement effects of CMC. Texts and CMC time with friends predicted friend closeness after accounting for FtF time with friends; texts with parents predicted parent closeness after accounting for FtF time with parents. We also found support for our hypothesis that CMC would be associated with greater adolescent volition. CMC time with parents predicted greater volitional dependence (volition plus closeness) whereas texts with friends predicted greater independent decision-making (volition plus distance). We discuss how communication technologies are integrated into U.S. adolescents' relationships with friends and parents and how CMC can facilitate, rather than stifle, adolescents' adjustment of autonomy-relatedness with parents and their construction of emotional closeness with friends
Free N-heterocyclic carbenes from Brønsted acidic ionic liquids: Direct detection by electrospray ionization mass spectrometry
Rationale: The occurrence of N-heterocyclic carbenes in imidazolium-based ionic liquids has long been discussed, but no spectroscopic evidence has been reported yet due to their transient nature. The insertion of an ionizable acid group into the cation scaffold of an ionic liquid which acts as a charge tag allows for the direct detection of free carbenes by mass spectrometry. Methods: Three different Brønsted acidic ionic liquids were synthesized: 1-methyl-3-carboxymethylimidazolium chloride (MAICl), 1-methyl-3-carboxymethylimidazolium acetate (MAIAc) and the corresponding 2-(3-methyl-1H-imidazol-3-ium-1-yl)acetate zwitterion (MAIâ-âH). The speciation of these compounds was then analysed by electrospray ionization ion-trap mass spectrometry in the negative ion mode. Results: The C2-H deprotonation of the imidazolium cation leading to the formation of the corresponding carbene is highly affected by the basic properties of the counter-anion. In the case of MAICl and MAIâ-âH ionic liquids, no charged species corresponding to the free N-heterocyclic carbene was detected. On the contrary, in the presence of a sufficiently basic anion, such as acetate of MAIAc ionic liquid, an intense signal related to the free carbenic species was observed without the addition of an external base. Conclusions: In situ formation of free N-heterocyclic carbenes from Brønsted acidic ionic liquids was demonstrated, highlighting the crucial role of anion basicity in promoting the C2-H proton abstraction from imidazolium cations with a carboxylic side chain.Rationale The occurrence of N-heterocyclic carbenes in imidazolium-based ionic liquids has long been discussed, but no spectroscopic evidence has been reported yet due to their transient nature. The insertion of an ionizable acid group into the cation scaffold of an ionic liquid which acts as a charge tag allows for the direct detection of free carbenes by mass spectrometry. Methods Three different Bronsted acidic ionic liquids were synthesized: 1-methyl-3-carboxymethylimidazolium chloride (MAICl), 1-methyl-3-carboxymethylimidazolium acetate (MAIAc) and the corresponding 2-(3-methyl-1H-imidazol-3-ium-1-yl)acetate zwitterion (MAI - H). The speciation of these compounds was then analysed by electrospray ionization ion-trap mass spectrometry in the negative ion mode. Results The C2-H deprotonation of the imidazolium cation leading to the formation of the corresponding carbene is highly affected by the basic properties of the counter-anion. In the case of MAICl and MAI - H ionic liquids, no charged species corresponding to the free N-heterocyclic carbene was detected. On the contrary, in the presence of a sufficiently basic anion, such as acetate of MAIAc ionic liquid, an intense signal related to the free carbenic species was observed without the addition of an external base. Conclusions In situ formation of free N-heterocyclic carbenes from Bronsted acidic ionic liquids was demonstrated, highlighting the crucial role of anion basicity in promoting the C2-H proton abstraction from imidazolium cations with a carboxylic side chain
Oxytocin Signaling in the Central Amygdala Modulates Emotion Discrimination in Mice
Recognition of other's emotions influences the way social animals interact and adapt to the environment. The neuropeptide oxytocin (OXT) has been implicated in different aspects of emotion processing. However, the role of endogenous OXT brain pathways in the social response to different emotional states in conspecifics remains elusive. Here, using a combination of anatomical, genetic, and chemogenetic approaches, we investigated the contribution of endogenous OXT signaling in the ability of mice to discriminate unfamiliar conspecifics based on their emotional states. We found that OXTergic projections from the paraventricular nucleus of the hypothalamus (PVN) to the central amygdala (CeA) are crucial for the discrimination of both positively and negatively valenced emotional states. In contrast, blocking PVN OXT release into the nucleus accumbens, prefrontal cortex, and hippocampal CA2 did not alter this emotion discrimination. Furthermore, silencing each of these PVN OXT pathways did not influence basic social interaction. These findings were further supported by the demonstration that virally mediated enhancement of OXT signaling within the CeA was sufficient to rescue emotion discrimination deficits in a genetic mouse model of cognitive liability. Our results indicate that CeA OXT signaling plays a key role in emotion discrimination both in physiological and pathological conditions. Is endogenous oxytocin implicated in emotion discrimination? Ferretti, Maltese et al. demonstrate that oxytocin signaling in the central amygdala plays a key role in the ability of mice to discriminate unfamiliar conspecifics based on their emotional state, both in physiological and genetically determined pathological conditions
Search for Point Sources of Ultra-High Energy Cosmic Rays Above 40 EeV Using a Maximum Likelihood Ratio Test
We present the results of a search for cosmic ray point sources at energies
above 40 EeV in the combined data sets recorded by the AGASA and HiRes stereo
experiments. The analysis is based on a maximum likelihood ratio test using the
probability density function for each event rather than requiring an a priori
choice of a fixed angular bin size. No statistically significant clustering of
events consistent with a point source is found.Comment: 7 pages, 7 figures. Accepted for publication in The Astrophysical
Journa
An upper limit on the electron-neutrino flux from the HiRes detector
Air-fluorescence detectors such as the High Resolution Fly's Eye (HiRes)
detector are very sensitive to upward-going, Earth-skimming ultrahigh energy
electron-neutrino-induced showers. This is due to the relatively large
interaction cross sections of these high-energy neutrinos and to the
Landau-Pomeranchuk-Migdal (LPM) effect. The LPM effect causes a significant
decrease in the cross sections for bremsstrahlung and pair production, allowing
charged-current electron-neutrino-induced showers occurring deep in the Earth's
crust to be detectable as they exit the Earth into the atmosphere. A search for
upward-going neutrino-induced showers in the HiRes-II monocular dataset has
yielded a null result. From an LPM calculation of the energy spectrum of
charged particles as a function of primary energy and depth for
electron-induced showers in rock, we calculate the shape of the resulting
profile of these showers in air. We describe a full detector Monte Carlo
simulation to determine the detector response to upward-going
electron-neutrino-induced cascades and present an upper limit on the flux of
electron-neutrinos.Comment: 13 pages, 3 figures. submitted to Astrophysical Journa
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