147 research outputs found
Swift chiral quantum walks
A continuous-time quantum walk (CTQW) is sedentary if the return probability
in the starting vertex is close to one at all times. Recent results imply that,
when starting from a maximal degree vertex, the CTQW dynamics generated by the
Laplacian and adjacency matrices are typically sedentary. In this paper, we
show that the addition of appropriate complex phases to the edges of the graph,
defining a chiral CTQW, can cure sedentarity and lead to swift chiral quantum
walks of the adjacency type, which bring the returning probability to zero in
the shortest time possible. We also provide a no-go theorem for swift chiral
CTQWs of the Laplacian type. Our results provide one of the first, general
characterization of tasks that can and cannot be achieved with chiral CTQWs.Comment: 20 pages, 2 figure
Quantum routing of information using chiral quantum walks
We address routing of classical and quantum information over quantum network,
and show how to exploit chirality to achieve nearly optimal and robust
transport. In particular, we prove how continuous time chiral quantum walks
over a minimal graph may be used to model directional transfer and routing of
information over a network. At first, we show how classical information,
encoded onto an excitation localized at one vertex of a simple graph, may be
sent to any other chosen location with nearly unit fidelity by tuning a single
phase. Then, we prove that high-fidelity transport is also possible for
coherent superpositions of states, i.e. for routing of quantum information.
Furthermore, we show that by tuning the phase parameter one obtains universal
quantum routing, i.e. indipendent on the input state. In our scheme, chirality
is governed by a single phase, and the routing probability is robust against
fluctuations of this parameter. Finally, we address characterization of quantum
routers and show how to exploit the self energies of the graph to achieve high
precision in estimating the phase parameter.Comment: This paper has been submitted to the Jonathan P. Dowling Memorial
Special Issue of AVS QUANTUM SCIENCE
(https://publishing.aip.org/publications/journals/special-topics/aqs/
Maternal caregiving moderates the impact of antenatal maternal cortisol on infant stress regulation
Background
Emerging evidence suggests that antenatal exposure to maternal stress signals affects the development of the infant stress response systems. Animal studies indicate that maternal sensitive caregiving can reverse some of these effects. However, the generalizability of these findings to humans is unknown. This study investigated the role of maternal caregiving in the association between multiple markers of maternal antenatal stress and infant stress regulation.
Methods
The sample consisted of 94 mother-infant (N = 47 males, mean postnatal weeks = 12; SD = 1.84) dyads. Maternal levels of Interleukin-6, C-Reactive Protein (CRP), diurnal cortisol and alpha amylase, depressive and anxiety symptoms were assessed in late pregnancy (mean gestational age = 34.76; SD = 1.12), whereas postnatal symptomatology, caregiving, and infant cortisol response to the inoculation were evaluated at 3 months.
Results
Hierarchical linear models (HLMs) showed a significant interaction between maternal antenatal cortisol, caregiving, and time on infant cortisol reactivity, while controlling for gender, maternal age, and postnatal depression. Specifically, higher levels of maternal antenatal cortisol were associated with greater cortisol response only among infants of less emotionally available mothers. All other markers of antenatal stress were not significantly associated with infant cortisol reactivity either independently or in interaction with maternal caregiving.
Conclusions
Albeit preliminary, results provide the first evidence in humans that maternal sensitive caregiving may eliminate the association between antenatal maternal cortisol and infant cortisol regulation
Neuroendocrine and immune markers of maternal stress during pregnancy and infant cognitive development
Antenatal exposure to maternal stress is a factor that may impact on offspring cognitive development. While some evidence exists of an association between maternal antenatal depressive or anxiety symptoms and infants’ cognitive outcomes, less is known about the role of biological indices of maternal antenatal stress in relation to infant cognitive development. The current study investigated the association between maternal depressive and anxiety symptoms, stress and inflammatory markers during pregnancy and infant’s cognitive development in a sample of 104 healthy pregnant women (mean gestational age=34.76; SD=1.12) and their 12-week-old infants (mean postnatal weeks=11.96; SD=1.85). Maternal depressive and anxiety symptoms were evaluated during pregnancy, alongside measurements of serum Interleukin-6 (IL-6), C-Reactive Protein (CRP), salivary cortisol and alpha amylase (sAA) concentrations. Infant cognitive development, maternal caregiving and concurrent anxiety or depressive symptoms were assessed 12 weeks after delivery. Hierarchical linear regressions indicated that higher maternal diurnal cortisol and CRP levels were independently associated with lower infant cognitive development scores, while adjusting for infant gender and gestational age, maternal IQ, caregiving, depressive or anxiety symptoms. Though correlational, findings seem suggestive of a role for variation in maternal biological stress signals during pregnancy in influencing infants’ early cognitive development
Cognitive deficits and brain myo-Inositol are early biomarkers of epileptogenesis in a rat model of epilepsy
One major unmet clinical need in epilepsy is the identification of therapies to prevent or arrest epilepsy development in patients exposed to a potential epileptogenic insult. The development of such treatments has been hampered by the lack of non-invasive biomarkers that could be used to identify the patients at-risk, thereby allowing to design affordable clinical studies. Our goal was to test the predictive value of cognitive deficits and brain astrocyte activation for the development of epilepsy following a potential epileptogenic injury. We used a model of epilepsy induced by pilocarpine-evoked status epilepticus (SE) in 21-day old rats where 60–70% of animals develop spontaneous seizures after around 70 days, although SE is similar in all rats. Learning was evaluated in the Morris water-maze at days 15 and 65 post-SE, each time followed by proton magnetic resonance spectroscopy for measuring hippocampal myo-Inositol levels, a marker of astrocyte activation. Rats were video-EEG monitored for two weeks at seven months post-SE to detect spontaneous seizures, then brain histology was done. Behavioral and imaging data were retrospectively analysed in epileptic rats and compared with non-epileptic and control animals. Rats displayed spatial learning deficits within three weeks from SE. However, only epilepsy-prone rats showed accelerated forgetting and reduced learning rate compared to both rats not developing epilepsy and controls. These deficits were associated with reduced hippocampal neurogenesis. myo-Inositol levels increased transiently in the hippocampus of SE-rats not developing epilepsy while this increase persisted until spontaneous seizures onset in epilepsy-prone rats, being associated with a local increase in S100β-positive astrocytes. Neuronal cell loss was similar in all SE-rats. Our data show that behavioral deficits, together with a non-invasive marker of astrocyte activation, predict which rats develop epilepsy after an acute injury. These measures have potential clinical relevance for identifying individuals at-risk for developing epilepsy following exposure to epileptogenic insults, and consequently, for designing adequately powered antiepileptogenesis trials
DNA barcoding to trace Medicinal and Aromatic Plants from the field to the food supplement
The global market of food supplements is growing, along with consumers demand for high-quality herbal products. Nevertheless, substitution fraud, and adulteration cases remain a common safety problem of global concern. In the last years, the DNA barcoding approach has been proposed as a valid identification method and it is now commonly used in the authentication of herbal and food products. The objective of this study was to evaluate whether DNA barcoding can be applied to trace the plant species from the starting raw material to the finished commercial products. We selected a panel of 28 phytoextracts obtained through three different extraction methods (i.e., maceration, percolation and sonication) with different solvents (i.e., ethanol, deionized water and glycerol). Furthermore, we chose six plant species for which we collected and analysed all the intermediates of the industrial production. We sequenced and analyzed the sequence variability at DNA barcoding (psbA-trnH, ITS) and minibarcoding (rbcL 1-B) marker regions. Phytoextracts obtained through hydroalcoholic treatment, with the lower percentage of ethanol (<40%), and aqueous processing, at the lowest temperature, had major rate of sequencing and identification success. This study proves that DNA barcoding is a useful tool for Medicinal and Aromatic Plants (MAPs) traceability, which would provide consumers with safe and high-quality herbal products
Quantitative ultrasound fatty liver evaluation in a pediatric population: comparison with magnetic resonance imaging of liver proton density fat fraction
Background: Biopsy remains the gold standard for the diagnosis of hepatic steatosis, the leading cause of pediatric chronic liver disease; however, its costs call for less invasive methods. Objective: This study examined the diagnostic accuracy and reliability of quantitative ultrasound (QUS) for the assessment of liver fat content in a pediatric population, using magnetic resonance imaging proton density fat fraction (MRI-PDFF) as the reference standard. Materials and methods: We enrolled 36 patients. MRI-PDFF involved a 3-dimensional T2*-weighted with Dixon pulse multiple-echo sequence using iterative decomposition of water and fat with echo asymmetry and least squares estimation (IDEAL IQ). QUS imaging relied on the ultrasound system "RS85 A" (Samsung Medison, Seoul, South Korea) and the following software: Hepato-Renal Index with automated region of interest recommendation (EzHRI), Tissue Attenuation Imaging (TAI), and Tissue Scatter Distribution Imaging (TSI). For each QUS index, receiver operating characteristic (ROC) curve analysis against MRI-PDFF was used to identify the associated cut-off value and the area under the ROC curve (AUROC). Concordance between two radiologists was assessed by intraclass correlation coefficients (ICCs) and Bland-Altman analysis. Results: A total of 61.1% of the sample (n=22) displayed a MRI-PDFF ≥ 5.6%; QUS cut-off values were TAI=0.625 (AUROC 0.90, confidence interval [CI] 0.77-1.00), TSI=91.95 (AUROC 0.99, CI 0.98-1.00) and EzHRI=1.215 (AUROC 0.98, CI 0.94-1.00). Inter-rater reliability was good-to-excellent for EzHRI (ICC 0.91, 95% C.I. 0.82-0.95) and TAI (ICC 0.94, 95% C.I. 0.88-0.97) and moderate to good for TSI (ICC 0.73; 95% C.I. 0.53-0.85). Conclusion: Our results suggest that QUS can be used to reliably assess the presence and degree of pediatric hepatic steatosis
Latent classes of emotional and behavioural problems in epidemiological and referred samples and their relations to DSM-IV diagnoses
Researchers\u2019 interest have recently moved toward the identification of recurrent psychopathological profiles characterized by concurrent elevations on different behavioural and emotional traits. This new strategy turned to be useful in terms of diagnosis and outcome prediction. We used a person-centred statistical approach to examine whether different groups could be identified in a referred sample and in a general-population sample of children and adolescents, and we investigated their relation to DSM-IV diagnoses. A latent class analysis (LCA) was performed on the Child Behaviour Checklist (CBCL) syndrome scales of the referred sample (N = 1225), of the general-population sample (N = 3418), and of the total sample. Models estimating 1-class through 5-class solutions were compared and agreement in the classification of subjects was evaluated. Chi square analyses, a logistic regression, and a multinomial logistic regression analysis were used to investigate the relations between classes and diagnoses. In the two samples and in the total sample, the best-fitting models were 4-class solutions. The identified classes were Internalizing Problems (15.68%), Severe Dysregulated (7.82%), Attention/Hyperactivity (10.19%), and Low Problems (66.32%). Subsequent analyses indicated a significant relationship between diagnoses and classes as well as a main association between the severe dysregulated class and comorbidity. Our data suggested the presence of four different psychopathological profiles related to different outcomes in terms of psychopathological diagnoses. In particular, our results underline the presence of a profile characterized by severe emotional and behavioural dysregulation that is mostly associated with the presence of multiple diagnosis
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