29 research outputs found

    Spin-chain model of a many-body quantum battery

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    Recently, it has been shown that energy can be deposited on a collection of quantum systems at a rate that scales super-extensively. Some of these schemes for `quantum batteries' rely on the use of global many-body interactions that take the batteries through a correlated short cut in state space. Here, we extend the notion of a quantum battery from a collection of a priori isolated systems to a many-body quantum system with intrinsic interactions. Specifically, we consider a one-dimensional spin chain with physically realistic two-body interactions. We find that the spin-spin interactions can yield an advantage in charging power over the non-interacting case, and we demonstrate that this advantage can grow super-extensively when the interactions are long ranged. However, we show that, unlike in previous work, this advantage is a mean-field interaction effect that does not involve correlations and that relies on the interactions being intrinsic to the battery.Comment: 9 pages, 6 figure

    Identification of Variables Contributing to Superovulation Efficiency for Production of Transgenic Prairie Voles (Microtus ochrogaster)

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    Background: The prairie vole (Microtus ochrogaster) is an emerging animal model for biomedical research because of its rich sociobehavioral repertoire. Recently, lentiviral transgenic technology has been used to introduce the gene encoding the green fluorescent protein (GFP) into the prairie vole germline. However, the efficiency of transgenesis in this species is limited by the inability to reliably produce large numbers of fertilized embryos. Here we examined several factors that may contribute to variability in superovulation success including, age and parentage of the female, and latency to mating after being placed with the male. Methods: Females produced from 5 genetically distinct breeder lines were treated with 100 IU of pregnant mare serum gonadotrophin (PMSG) and immediately housed with a male separated by a perforated Plexiglas divider. Ovulation was induced 72 hr later with 30 IU of human chorionic gonadotropin (hCG) and 2 hrs later mating was allowed. Results: Superovulation was most efficient in young females. For example, females aged 6-11 weeks produced more embryos (14 +/- 1.4 embryos) as compared to females aged 12-20 weeks (4 +/- 1.6 embryos). Females aged 4-5 weeks did not produce embryos. Further, females that mated within 15 min of male exposure produced significantly more embryos than those that did not. Interestingly, there was a significant effect of parentage. For example, 12 out of 12 females from one breeder pair superovulated (defined as producing 5 or more embryos), while only 2 out of 10 females for other lines superovulated. Conclusions: The results of this work suggest that age and genetic background of the female are the most important factors contributing to superovulation success and that latency to mating is a good predictor of the number of embryos to be recovered. Surprisingly we found that cohabitation with the male prior to mating is not necessary for the recovery of embryos but is necessary to recover oocytes. This information will dramatically reduce the number of females required to generate embryos for transgenesis in this species

    Examining impulsivity as an endophenotype using a behavioral approach: a DRD2 TaqI A and DRD4 48-bp VNTR association study

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    BACKGROUND: Research on the genetic basis for impulsivity has revealed an array of ambiguous findings. This may be a result of limitations to self-report assessments of impulsivity. Behavioral measures that assess more narrowly defined aspects of impulsivity may clarify genetic influences. This study examined the relationship between possession of the DRD2 TaqI A and DRD4 48 bp VNTR genetic polymorphisms and performance on a behavioral measure of impulsivity, the delay discounting task (DDT), and three traditional self-report measures. METHODS: 195 individuals (42% male) were recruited from a university campus and were assessed in small group sessions using personal computers. Genotyping was conducted using previously established protocols. For the DRD2 TaqI A locus, individuals were designated as possessing at least one copy of the A1 allele (A1+) or not (A1-), and for the DRD4 48-bp VNTR locus, individuals were designated as having at least one long allele (7 repeats or longer, L+) or not (L-). Principal analyses used multiple univariate factorial 2 (A1+/A1-) × 2 (L+/L-) analyses of variance. RESULTS: A significant main effect of A1+ status on DDT performance was evident (p = .006) as well as a significant interaction effect (p = .006) between both genes. No other significant effects were evident on the self-report measures, with the exception of a trend toward an interaction effect on the Sensation Seeking Scale. Exploratory analyses suggested that the significant effects were not a function of population stratification or gender. DISCUSSION: These data suggest that the DRD2 TaqI A and DRD4 VNTR polymorphisms influence impulsivity as measured with a delay discounting task. Specifically, these findings suggest that an interaction between the functional effects of the two unlinked genotypes results in significant difference in the balance of mesolimbic dopaminergic activation relative to frontal-parietal activation. However, these findings are also the first in this area and must be replicated. CONCLUSION: These findings suggest a meaningful interaction between the DRD2 TaqI A and DRD4 VNTR polymorphisms in the expression of impulsivity and provide initial support for the utility of using behavioral measures for clarifying genetic influences on impulsivity

    Shifted phase of EEG cross-frequency coupling in individuals with Phelan-McDermid syndrome

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    Background Phelan-McDermid Syndrome (PMS) is a rare condition caused by deletion or mutation of the SHANK3 gene. Individuals with PMS frequently present with intellectual disability, autism spectrum disorder, and other neurodevelopmental challenges. Electroencephalography (EEG) can provide a window into network-level function in PMS. Methods Here, we analyze EEG data collected across multiple sites in individuals with PMS (n = 26) and typically developing individuals (n = 15). We quantify oscillatory power, alpha-gamma phase-amplitude coupling strength, and phase bias, a measure of the phase of cross frequency coupling thought to reflect the balance of feedforward (bottom-up) and feedback (top-down) activity. Results We find individuals with PMS display increased alpha-gamma phase bias (U = 3.841, p < 0.0005), predominantly over posterior electrodes. Most individuals with PMS demonstrate positive overall phase bias while most typically developing individuals demonstrate negative overall phase bias. Among individuals with PMS, strength of alpha-gamma phase-amplitude coupling was associated with Sameness, Ritualistic, and Compulsive behaviors as measured by the Repetitive Behavior Scales-Revised (Beta = 0.545, p = 0.011). Conclusions Increased phase bias suggests potential circuit-level mechanisms underlying phenotype in PMS, offering opportunities for back-translation of findings into animal models and targeting in clinical trials

    Signatures of quantum chaos in an out-of-time-order matrix

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    Motivated by the famous ink-drop experiment, where ink droplets are used to determine the chaoticity of a fluid, we propose an experimentally implementable method for measuring the scrambling capacity of quantum processes. Here, a system of interest interacts with a small quantum probe whose dynamical properties identify the chaoticity of the system. Specifically, we propose a fully quantum version of the out-of-time-order correlator (OTOC) - which we term the out-of-time-order matrix (OTOM) - whose correlations offer clear information theoretic meanings about the chaoticity of a process. We illustrate the utility of the OTOM as a signature of chaos using random unitary processes as well as in the quantum kicked rotor, where the chaoticity is tuneable

    Polymorphisms in the Dopamine D4 and D2 Receptor Genes and Reproductive and Sexual Behaviors

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    Human reproductive and sexual behaviors are heritable and may represent integral life history traits that are likely partially subserved by the dopamine system. Two dopamine receptor polymorphisms, DRD4 48bp VNTR and DRD2 TaqI A , were examined in relation to the Sexual-Orientation Inventory (SOI), age at first sexual intercourse, desired age of marriage, and desired age to have children in 195 (45% male) individuals from a general student population. As DRD4 7R alleles have been associated with migratory behavior, we also examined whether those with more 7R alleles had a greater frequency of multi-racial ancestries. Minor alleles of both polymorphisms (7R and A1 respectively) are believed to decrease the function of their respective receptors. Individuals with DRD4 7R alleles were more likely to have had sexual intercourse and to desire children earlier in life. In addition, DRD4 7R+ individuals were more likely to report multi-racial ancestries. Individuals with DRD2 A1 alleles were more likely to not want children and not want to marry. These results suggest that polymorphisms in the DRD4 and DRD2 genes are meaningfully associated with variation in reproductive and sexual behaviors. These results are provisionally interpreted as consistent with other findings suggesting that DRD4 7R and DRD2 A1 alleles are adaptive for lower offspring investment strategies in dynamic social environments

    Evaluation of polymerase chain reaction using protein b primers for rapid diagnosis of tuberculous meningitis

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    Background: Rapid and specific diagnosis of tubercular meningitis (TBM) is of utmost importance. Aim: To evaluate polymerase chain reaction (PCR) using protein b primers directed against M. tuberculosis for the diagnosis of tuberculous meningitis. Materials and Methods: PCR using protein b primers was performed in ten patients with confirmed TBM (culture positive), 60 patients with clinically suspected TBM and 40 patients with no TBM (control group). Results: Protein b PCR had a sensitivity of 90% and a specificity of 100% in patients with confirmed TBM. In 60 clinically diagnosed TBM patients, protein b PCR was positive in 49 (81.7%) patients. The overall sensitivity of microscopy, culture and PCR using protein b primers was 1.4%, 14.3%, and 82.8% and specificity was 100%, 100%, and 100% respectively. Conclusion: Protein b PCR is valuable in rapid diagnosis of TBM

    Evaluation of PCR using MPB64 Primers for Rapid Diagnosis of Tuberculous Meningitis

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    TBM control group and its comparison with conventional techniques like microscopy and culture. Materials and Methods A total of 130 CSF samples received for AFB smear and culture in laboratory of tertiary care hospital of India, between September 2008 and December 2009 were evaluated. Patient&apos;s age ranged from 12-90 years. The relevant history and other details of the patients were noted from the case records. The patients were divided into 3 groups: Group I: TBM (n=90): (a) confirmed TBM-culture/smear positive (n=9), and (b) suspected TBM: smear/culture negative, clinical and laboratory features suggestive of TBM and response to anti-tuberculosis therapy Processing of CSF sample All the 130 CSF samples were subjected to three microbiological tests: Ziehl-Neelsen staining (ZN), culture on Lowenstein-Jensen medium and PCR with MPB-64. The CSF samples of the subjects were Keywords: PCR; Tubercular meningitis Introduction Tuberculosis is a major cause of morbidity and mortality worldwide. The World Health Organization has noted that the global incidence of TB is increasing by 0.4% per annum The development of rapid, sensitive and specific test for detection of mycobacterium has been a long standing need. A number of mycobacterial antigen Nucleic Acid Amplification Techniques (NAAT) such as Polymerase Chain Reaction (PCR) has been reported to be more sensitive and specific. Several Mycobacterium tuberculosis specific sequences like IS6110, Protein antigen b [8], MPB64 and 65 kDa have been evaluated Abstract Purpose: Diagnosis of Tuberculosis (TB) is largely based on microscopy and culture, which either lack of sensitivity or time consuming. In the present study a PCR test based on DNA sequence coding for MPB64, specific for Mycobacterium tuberculosis was compared with Ziehl-Neelson (ZN) stained AFB smear examination, culture based on conventional LJ medium for diagnosis of tuberculosis using clinical samples obtained from Cerebro-Spinal Fluid (CSF) samples from TBM patients. Methods: PCR using MPB64 primers was performed on 9 TBM confirmed (culture was positive), 81TBM suspected and 40 Non TBM (control group) patients. Results: MPB64 PCR had sensitivity of 88.8% and specificity of 100% for confirmed TBM cases, where as in 81 clinically diagnosed but unconfirmed TBM cases MPB64 PCR was positive in 81.48% cases respectively. The overall sensitivity of microscopy, culture and PCR using MPB64 were 1.11%, 10%, 82.22% and specificity was 100%, 100% and 100% respectively
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