396 research outputs found
Ab initio molecular dynamics study of manganese porphine hydration and interaction with nitric oxide
The authors use ab initio molecular dynamics and the density functional
theory+U (DFT+U) method to compute the hydration environment of the manganese
ion in manganese (II) and manganese (III) porphines (MnP) dispersed in liquid
water. These are intended as simple models for more complex water soluble
porphyrins, which have important physiological and electrochemical
applications. The manganese ion in Mn(II)P exhibits significant out-of-porphine
plane displacement and binds strongly to a single H2O molecule in liquid water.
The Mn in Mn(III)P is on average coplanar with the porphine plane and forms a
stable complex with two H2O molecules. The residence times of these water
molecules exceed 15 ps. The DFT+U method correctly predicts that water
displaces NO from Mn(III)P-NO, but yields an ambiguous spin state for the
MnP(II)-NO complex.Comment: 10 pages, 6 figure
Mobility-Induced Service Migration in Mobile Micro-Clouds
Mobile micro-cloud is an emerging technology in distributed computing, which
is aimed at providing seamless computing/data access to the edge of the network
when a centralized service may suffer from poor connectivity and long latency.
Different from the traditional cloud, a mobile micro-cloud is smaller and
deployed closer to users, typically attached to a cellular basestation or
wireless network access point. Due to the relatively small coverage area of
each basestation or access point, when a user moves across areas covered by
different basestations or access points which are attached to different
micro-clouds, issues of service performance and service migration become
important. In this paper, we consider such migration issues. We model the
general problem as a Markov decision process (MDP), and show that, in the
special case where the mobile user follows a one-dimensional asymmetric random
walk mobility model, the optimal policy for service migration is a threshold
policy. We obtain the analytical solution for the cost resulting from arbitrary
thresholds, and then propose an algorithm for finding the optimal thresholds.
The proposed algorithm is more efficient than standard mechanisms for solving
MDPs.Comment: in Proc. of IEEE MILCOM 2014, Oct. 201
Dynamical simulation of transport in one-dimensional quantum wires
Transport of single-channel spinless interacting fermions (Luttinger liquid)
through a barrier has been studied by numerically exact quantum Monte Carlo
methods. A novel stochastic integration over the real-time paths allows for
direct computation of nonequilibrium conductance and noise properties. We have
examined the low-temperature scaling of the conductance in the crossover region
between a very weak and an almost insulating barrier.Comment: REVTex, 4 pages, 2 uuencoded figures (submitted to Phys. Rev. Lett.
Multimode photon blockade
Interactions are essential for the creation of correlated quantum many-body
states. While two-body interactions underlie most natural phenomena, three- and
four-body interactions are important for the physics of nuclei [1], exotic
few-body states in ultracold quantum gases [2], the fractional quantum Hall
effect [3], quantum error correction [4], and holography [5, 6]. Recently, a
number of artificial quantum systems have emerged as simulators for many-body
physics, featuring the ability to engineer strong interactions. However, the
interactions in these systems have largely been limited to the two-body
paradigm, and require building up multi-body interactions by combining two-body
forces. Here, we demonstrate a pure N-body interaction between microwave
photons stored in an arbitrary number of electromagnetic modes of a multimode
cavity. The system is dressed such that there is collectively no interaction
until a target total photon number is reached across multiple distinct modes,
at which point they interact strongly. The microwave cavity features 9 modes
with photon lifetimes of ms coupled to a superconducting transmon
circuit, forming a multimode circuit QED system with single photon
cooperativities of . We generate multimode interactions by using
cavity photon number resolved drives on the transmon circuit to blockade any
multiphoton state with a chosen total photon number distributed across the
target modes. We harness the interaction for state preparation, preparing Fock
states of increasing photon number via quantum optimal control pulses acting
only on the cavity modes. We demonstrate multimode interactions by generating
entanglement purely with uniform cavity drives and multimode photon blockade,
and characterize the resulting two- and three-mode W states using a new
protocol for multimode Wigner tomography.Comment: 5 pages of main text with 5 figures. 11 pages of supplementary
information with 10 figure
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Effects of mother-offspring and father-offspring dynamics on emerging adults’ adjustment: The mediating role of emotion regulation
The present study tested a theoretical model of emotion regulation between parent-offspring dynamics and emerging adults’ adjustment. The mediating role of emotion regulation strategies, including cognitive reappraisal and expressive suppression, were investigated for the effects of mother-offspring and father-offspring dynamics on emerging adults’ adjustment. A sample of 352 Chinese emerging adults in Hong Kong (230 female, 121 male) participated in this study. Participants were asked to complete a set of self-reported questionnaires. Findings based on structural equation modeling indicated that greater mother-offspring intimacy and father-offspring intimacy predicted emerging adults’ better cognitive reappraisal and psychological, social, and general health. Greater mother-offspring conflict also predicted more expressive suppression and poorer psychological and social functioning. Distinctive mediation pathways as a function of parents’ gender were identified. These findings enrich the literature for parent-offspring dynamics and emotion regulation as explanatory processes of emerging adults’ adjustment
A pilot controlled trial of a combination of dense cranial electroacupuncture stimulation and body acupuncture for post-stroke depression
BACKGROUND: Our previous studies have demonstrated the treatment benefits of dense cranial electroacupuncture stimulation (DCEAS), a novel brain stimulation therapy in patients with major depression, postpartum depression and obsessive-compulsive disorder. The purpose of the present study was to further evaluate the effectiveness of DCEAS combined with body acupuncture and selective serotonin reuptake inhibitors (SSRIs) in patients with post-stroke depression (PSD). METHODS: In a single-blind, randomized controlled trial, 43 patients with PSD were randomly assigned to 12 sessions of DCEAS plus SSRI plus body electroacupuncture (n = 23), or sham (non-invasive cranial electroacupuncture, n-CEA) plus SSRI plus body electroacupuncture (n = 20) for 3 sessions per week over 4 weeks. Treatment outcomes were measured using the 17-item Hamilton Depression Rating Scale (HAMD-17), the Clinical Global Impression - Severity scale (CGI-S) and Barthel Index (BI), a measure used to evaluate movement ability associated with daily self-caring activity. RESULTS: DCEAS produced a significantly greater reduction of both HAMD-17 and CGI-S as early as week 1 and CGI-S at endpoint compared to n-CEA, but subjects of n-CEA group exhibited a significantly greater improvement on BI at week 4 than DCEAS. Incidence of adverse events was not different in the two groups. CONCLUSIONS: These results indicate that DCEAS could be effective in reducing stroke patients’ depressive symptoms. Superficial electrical stimulation in n-CEA group may be beneficial in improving movement disability of stroke patients. A combination of DCEAS and body acupuncture can be considered a treatment option for neuropsychiatric sequelae of stroke. TRIAL REGISTRATION: http://www.clinicaltrials.gov, NCT01174394
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