153 research outputs found
Phenyl 4,6-di-O-acetyl-2,3-dideoxy-1-thio-α-d-erythro-hex-2-enopyranoside
The pyranosyl ring in the title compound, C16H18O5S, adopts an envelope conformation, with the acetyl groups in equatorial positions. In the crystal, weak C—H⋯O interactions link the molecules into chains
Two-Stage Kondo Effect and Kondo Box Level Spectroscopy in a Carbon Nanotube
The concept of the "Kondo box" describes a single spin, antiferromagnetically
coupled to a quantum dot with a finite level spacing. Here, a Kondo box is
formed in a carbon nanotube interacting with a localized electron. We
investigate the spins of its first few eigenstates and compare them to a recent
theory. In an 'open' Kondo-box, strongly coupled to the leads, we observe a
non-monotonic temperature dependence of the nanotube conductance, which results
from a competition between the Kondo-box singlet and the 'conventional' Kondo
state that couples the nanotube to the leads.Comment: 5 pages, 3 figure
Effects of maternal suicidal ideation on child cognitive development: A longitudinal analysis
This study aimed to assess the association between suicidal ideation among mothers living with HIV in Zimbabwe and the cognitive development of their children. Participants were mother–child dyads recruited from two rural districts in Zimbabwe. Data were collected at baseline and 12 months follow-up. Suicidal ideation was assessed using item-10 from the Edinburgh postnatal depression scale. Mixed-effects linear regression was used to assess the association of child cognitive outcomes at follow-up (using the Mullen scales of early learning) with maternal suicidal ideation. Mothers with suicidal ideation at baseline (n = 171) tended to be younger, unmarried, experienced moderate to severe hunger, had elevated parental stress and depression symptoms compared with non-suicidal mothers (n = 391). At follow-up, emerging maternal suicidal ideation was associated with poorer child cognitive outcomes (adjusted mean difference − 6.1; 95% CI − 10.3 to − 1.8; p = 0.03). Suicidal ideation affects child cognitive development and should be addressed, particularly in HIV positive mothers
Resonant Tunneling in a Dissipative Environment
We measure tunneling through a single quantum level in a carbon nanotube
quantum dot connected to resistive metal leads. For the electrons tunneling
to/from the nanotube, the leads serve as a dissipative environment, which
suppresses the tunneling rate. In the regime of sequential tunneling, the
height of the single-electron conductance peaks increases as the temperature is
lowered, although it scales more weekly than the conventional 1/T. In the
resonant tunneling regime (temperature smaller than the level width), the peak
width approaches saturation, while the peak height starts to decrease. Overall,
the peak height shows a non-monotonic temperature dependence. We associate this
unusual behavior with the transition from the sequential to the resonant
tunneling through a single quantum level in a dissipative environment.Comment: 5 pages, 5 figure
Effects of Maternal Suicidal Ideation on Child Cognitive Development: A Longitudinal Analysis.
This study aimed to assess the association between suicidal ideation among mothers living with HIV in Zimbabwe and the cognitive development of their children. Participants were mother-child dyads recruited from two rural districts in Zimbabwe. Data were collected at baseline and 12 months follow-up. Suicidal ideation was assessed using item-10 from the Edinburgh postnatal depression scale. Mixed-effects linear regression was used to assess the association of child cognitive outcomes at follow-up (using the Mullen scales of early learning) with maternal suicidal ideation. Mothers with suicidal ideation at baseline (n = 171) tended to be younger, unmarried, experienced moderate to severe hunger, had elevated parental stress and depression symptoms compared with non-suicidal mothers (n = 391). At follow-up, emerging maternal suicidal ideation was associated with poorer child cognitive outcomes (adjusted mean difference - 6.1; 95% CI - 10.3 to - 1.8; p = 0.03). Suicidal ideation affects child cognitive development and should be addressed, particularly in HIV positive mothers
Quantum switches and quantum memories for matter-wave lattice solitons
We study the possibility of implementing a quantum switch and a quantum
memory for matter wave lattice solitons by making them interact with
"effective" potentials (barrier/well) corresponding to defects of the optical
lattice. In the case of interaction with an "effective" potential barrier, the
bright lattice soliton experiences an abrupt transition from complete
transmission to complete reflection (quantum switch) for a critical height of
the barrier. The trapping of the soliton in an "effective" potential well and
its release on demand, without loses, shows the feasibility of using the system
as a quantum memory. The inclusion of defects as a way of controlling the
interactions between two solitons is also reported
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