Generation of maximum spin entanglement induced by cavity field in quantum-dot systems

Equivalent-neighbor interactions of the conduction-band electron spins of quantum dots in the model of Imamoglu et al. [Phys. Rev. Lett. 83, 4204 (1999)] are analyzed. Analytical solution and its Schmidt decomposition are found and applied to evaluate how much the initially excited dots can be entangled to the remaining dots if all of them are initially disentangled. It is demonstrated that the perfect maximally entangled states (MES) can only be generated in the systems of up to 6 dots with a single dot initially excited. It is also shown that highly entangled states, approximating the MES with a good accuracy, can still be generated in systems of odd number of dots with almost half of them being excited. A sudden decrease of entanglement is observed by increasing the total number of dots in a system with a fixed number of excitations.Comment: 6 pages, 7 figures, to appear in Phys. Rev.

Periodontal screening and referral behaviour of general dental practitioners in Flanders.

peer reviewedOBJECTIVES: The objective of this study was to investigate the screening and referral behaviour of Flemish dentists concerning periodontitis and more specific, the use of the Dutch Periodontal Screening Index (DPSI). MATERIALS AND METHODS: An online questionnaire was electronically distributed through the different professional dental societies. It consisted of two parts: the first aimed at describing the profile of the dentist. The second part inquired the screening method, when this was applied, periodontal risk factors and referral behaviour. RESULTS: One thousand fifty dentists attended to the questionnaire. One hundred fifty-nine questionnaires were excluded since they did not match the target audience. Sixty-four percent of Flemish dentists used DPSI as a periodontal screening method, 28% screened based on probing pocket depth, 4% used solely radiographs and 4% had no screening method at all. The usage of DPSI is influenced by the year of graduation: the longer the dentists were graduated, the less they used DPSI. No influence of sex, education centre and location was found. Referral behaviour is influenced by different patient- and dentist-related factors. CONCLUSIONS: Regarding the screening behaviour, there seems a consensus among Flemish dentists that a periodontal probe should be used. For referral, there is no consensus about if and when to refer to a specialist. CLINICAL RELEVANCE: It is encouraging that 92% of the Flemish general dental practitioners use a probe when screening for periodontitis. However, DPSI is mainly used by younger dentists. An effort should be made to encourage all dentists to use this, so that in every patient, periodontitis can be detected timely, securing the best treatment outcome

Alternative therapies in controlling oral malodour: a systematic review.

peer reviewedIs there a role for alternative therapies in controlling intra-oral halitosis? Treatments other than tongue cleaning and anti-halitosis products containing zinc, chlorhexidine and cetylpyridinium chloride were considered as alternative therapies. Four databases were searched (PubMed, EMBASE, Web of Science and The Cochrane Library). Inclusion criteria were: examination of alternative halitosis therapies, study population with oral malodour, a (negative or positive) control group and evaluation of breath odour via organoleptic and/or instrumental assessment. Data were extracted for descriptive analysis. The screening of 7656 titles led to the inclusion of 26 articles. Analysis showed heterogeneity concerning the population of interest (from cysteine-induced to genuine halitosis), the examined treatment and the reported outcomes. This made a meta-analysis impossible. Essential oils, fluoride-containing products and herbal substances were the most studied. Results varied enormously and none of the active ingredients had an unambiguously positive effect on the malodour. The risk of bias was assessed as high in all articles. Given the fact that little evidence was found for each of the investigated treatments, it could be concluded that there is currently insufficient evidence that alternative therapies are of added value in the treatment of halitosis.Clinical relevanceScientific rationale:Halitosis is a common problem causing social isolation. Out of embarrassment, patients search the internet, leading to many questions about alternative solutions (e.g. oil pulling, herbs). This is the first systematic review on these alternative therapies.Principal findings: Results varied among studies. Some promising results were found for fluoride-containing toothpastes and probiotics. For other products (such as herbal and antibacterial products and essential oils) results were inconsistent. Long-term follow-up studies on these products are scarce. Moreover, the quality of the studies was poor.Practical implications:No clear evidence was found to support a certain alternative anti-halitosis therapy

Morphosyntactic processing in late second-language learners

The goal of the present study was to investigate the electro- physiological correlates of second-language (L2) morphosyn- tactic processing in highly proficient late learners of an L2 with long exposure to the L2 environment. ERPs were col- lected from 22 English–Spanish late learners while they read sentences in which morphosyntactic features of the L2 present or not present in the first language (number and gender agree- ment, respectively) were manipulated at two different sentence positions—within and across phrases. The results for a control group of age-matched native-speaker Spanish participants in- cluded an ERP pattern of LAN-type early negativity followed by P600 effect in response to both agreement violations and for both sentence positions. The late L2 learner results included a similar pattern, consisting of early negativity followed by P600, in the first sentence position (within-phrase agreement viola- tions) but only P600 effects in the second sentence position (across-phrase agreement violation), as well as significant am- plitude and onset latency differences between the gender and the number violation effects in both sentence positions. These results reveal that highly proficient learners can show electro- physiological correlates during L2 processing that are qualita- tively similar to those of native speakers, but the results also indicate the contribution of factors such as age of acquisition and transfer processes from first language to L

Dimension in a Radiative Stellar Atmosphere

Dimensional scales are examined in an extended 3+1 Vaidya atmosphere surrounding a Schwarzschild source. At one scale, the Vaidya null fluid vanishes and the spacetime contains only a single spherical 2-surface. Both of these behaviors can be addressed by including higher dimensions in the spacetime metric.Comment: to appear in Gen. Rel. Gra

Significant Surface-Water Connectivity of Geographically Isolated Wetlands

We evaluated the current literature, coupled with our collective research expertise, on surface-water connectivity of wetlands considered to be geographically isolated (sensu Tiner Wetlands 23:494–516, 2003a) to critically assess the scientific foundation of grouping wetlands based on the singular condition of being surrounded by uplands. The most recent research on wetlands considered to be geographically isolated shows the difficulties in grouping an ecological resource that does not reliably indicate lack of surface water connectivity in order to meet legal, regulatory, or scientific needs. Additionally, the practice of identifying geographically isolated wetlands based on distance from a stream can result in gross overestimates of the number of wetlands lacking ecologically important surface-water connections. Our findings do not support use of the overly simplistic label of geographically isolated wetlands . Wetlands surrounded by uplands vary in function and surface water connections based on wetland landscape setting, context, climate, and geographic region and should be evaluated as such. We found that the geographically isolated grouping does not reflect our understanding of the hydrologic variability of these wetlands and hence does not benefit conservation of the Nation’s diverse wetland resources. Therefore, we strongly discourage use of categorizations that provide overly simplistic views of surface water connectivity of wetlands fully embedded in upland landscapes

How Do Students Use Their Mobile Devices to Support Learning? A Case Study from an Australian Regional University

Though universities are eager to leverage the potential of mobile learning to provide learning flexibly, most balk at the cost of providing students with mobile hardware. The practice of ‘bring your own device’ (BYOD) is often mooted as a cost-effective alternative. This paper provides a snapshot of student ownership of mobile devices at a regional Australian university. Our research shows that students do have access to and use a wide range of devices. However, the delivery of learning is challenged when students try to access materials and activities using these devices. Course materials are rarely optimised for use on smartphones, navigating websites and learning management systems becomes a scrolling nightmare, and interacting with other students is often impractical using prescribed systems. Most concerning is that none of the students surveyed were participating in educator-led mobile learning initiatives. The paper concludes with the proposal of some practical, low-cost tactics that educators could potentially employ to begin engaging with mobile learning, leveraging what students already do