Green Up-Conversion Laser-Emission In Er-Doped Crystals At Room-Temperature

We report room-temperature pulsed up-conversion laser oscillation in Er-doped LiYF4 and KYF4 at 551 and 562 nm, respectively. In both crystals laser oscillation is observed on the S-4(3/2)-I-4(15/2) ground state transition. Excitation was provided by a tunable flashlamp-pumped Ti:sapphire laser in the spectral region around 810 nm. Additional pumping with a continuous wave krypton ion laser at 647 nm was beneficial to both lasers. Laser action has also been observed in Er-doped Y3Al5O12 on the same transition

Magnetic Properties of Monolayer Co Islands on Ir(111) Probed by Spin-Resolved Scanning Tunneling Microscopy

As the characteristic length scale of devices continues to decrease, it is essential to understand the fundamental magnetic properties of reduced dimension structures. This paper examines the electronic and magnetic properties of two-dimensional nanoscale Co islands on an Ir(111) surface using spin-polarized scanning tunneling microscopy. The pseudomorphic Co islands investigated are ferromagnetic and single domain, with the magnetic easy axis normal to the sample surface. Remarkably, the coercivity of these islands is greater than 4 T and magnetic saturation of the islands requires an applied field of at least 5 T

Magnetic Properties of Monolayer Co Islands on Ir(111) Probed by Spin-Resolved Scanning Tunneling Microscopy

As the characteristic length scale of devices continues to decrease, it is essential to understand the fundamental magnetic properties of reduced dimension structures. This paper examines the electronic and magnetic properties of two-dimensional nanoscale Co islands on an Ir(111) surface using spin-polarized scanning tunneling microscopy. The pseudomorphic Co islands investigated are ferromagnetic and single domain, with the magnetic easy axis normal to the sample surface. Remarkably, the coercivity of these islands is greater than 4 T and magnetic saturation of the islands requires an applied field of at least 5 T

Spectroscopy And Green Up-Conversion Laser-Emission Of Er(3+)-Doped Crystals At Room-Temperature

The spectroscopic parameters of Er3+-doped crystals were determined with regard to the upconversion laser parameters of the green transition S-4(3/2) -- \u3e I-4(15/2), The influence of excited-state absorption on this laser channel was determined. Furthermore, upconversion pump mechanisms using ground-state and excited-state absorption around 810 and 970 nm were investigated by direct measurements of excited-state absorption. The spectroscopic results confirm the pulsed room-temperature laser experiments on the S-4(3/2) -- \u3e I-5(5/2) transition. The lasers based on Er:LiYF4, Er:Y3Al5O12, and Er:Lu3Al5O12 were directly excited into the upper laser level by an excimer laser pumped dye laser in the blue spectral range. In Er:LiYF4, Er:KYF4, and Er:Y3Al5O12, laser action was achieved with two-step upconversion pumping by a Ti:sapphire laser and a krypton ion laser. In the case of the fluorides, the additional pumping with the krypton ion laser was not necessary. The laser emission wavelengths were 551 nm for Er:LiYF4, 561 nm for Er:Y3Al5012 and Er:Lu3Al5O12, and 562 nm for Er:KYF4. In addition, green quasi-cw laser emission of Er:LiYF4 pumped with an argon-ion laser was realized at room temperature

Executive function predicts school readiness in autistic and typical preschool children

Children’s emerging executive functions (EF) have been shown to be critical for a whole range of other functions, including school readiness and later academic success. Here we examine for the first time whether individual differences in EF are uniquely associated with autistic children’s readiness to learn in school, beyond general and developmental influences in age and ability. Thirty autistic and 30 typical preschool children, matched on age and ability, were assessed on EF (working memory, inhibition, set-shifting) and school readiness measures. Autistic children performed significantly worse on school readiness measures and EF measures relative to typical children. Furthermore, individual differences in children’s EF skills, especially in inhibitory control and working memory, were uniquely related to variation in their school readiness for both autistic and non-autistic children. The findings from this cross-sectional study provide further support for the potential role of EF in explaining the variability in autistic children’s functional outcomes

Excluded from school: Autistic students' experiences of school exclusion and subsequent re-integration into school

Background and aims: All children have the right to receive an education and to be included in school. Yet young people on the autism spectrum, who are already vulnerable to poor health and social outcomes, are at increased risk of school exclusion. The current study sought to understand the key factors surrounding the school exclusion experiences of a group of autistic students with particularly complex needs, and their subsequent re-integration into education. / Method: We interviewed nine intellectually able students (eight male, one female; M age = 13.3 years), all with a diagnosis of autism and the majority with a history of demand avoidant behaviour. We also interviewed their parents and teaching staff about the students’ past and current school experiences. All students were currently being educated within an ‘Inclusive Learning Hub’, specially designed to re-integrate excluded, autistic students back into school, which was situated within a larger autism special school. / Results: Young people and their parents gave overwhelmingly negative accounts of the students’ previous school experiences. Children’s perceived unmet needs, as well as inappropriate approaches by previous school staff in dealing with children’s difficulties, were felt to cause decline in children’s mental health and behaviour and, ultimately, led to their exclusion from school. Four key factors for successful reintegration into school were identified, including (i) making substantial adjustments to the physical environment, (ii) promoting strong staff–student relationships, (iii) understanding students’ specific needs, and (iv) targeted efforts towards improving students’ wellbeing. / Conclusion: The culmination – and escalation – of challenges students experienced in the students’ previous placements could suggest that the educational journey to exclusion from school is an inevitable consequence for at least some autistic children, including those with particularly complex behaviour, as sampled here. Yet, our study encouragingly showed that this was not necessarily the case. All the young people we spoke to reported being happy, safe and secure in their current placement, and re-engaged with school life. Outstanding issues remain, however, with regard to children’s reportedly slow academic progress and difficulties generalising the positive behaviour shown in school across home and community contexts. / Implications: More remains to be done to ensure that autistic children and young people’s progress at school is also mirrored in other settings. Future research also needs to develop more preventative approaches to avoid exclusion from school, including efforts towards improving education professionals’ knowledge and awareness of autism, and effective ways of responding to these students’ needs

Efficient screening for ‘genetic pollution’ in an anthropogenic crested newt hybrid zone

Genetic admixture between endangered native and non-native invasive species poses a complex conservation problem. Decision makers often need to quickly screen large numbers of individuals and distinguish natives from morphologically similar invading species and their genetically admixed offspring. We describe a protocol using the fast and economical Kompetitive Allele Specific PCR (KASP) technology for genotyping on a large scale. We apply this protocol to a case study of hybridization between a native and an invasive crested newt species. Using previously published data, we designed a panel of ten nuclear and one mitochondrial diagnostic SNP markers. We observed only minor differences between KASP and next-generation sequencing data previously produced with the Ion Torrent platform. We briefly discuss practical considerations for tackling the insidious conservation problem of genetic admixture between native and invasive species. The KASP genotyping protocol facilitates policy decision making for the crested newt case and is generally applicable to invasive hybridization with endangered taxa

Extending the definition of modularity to directed graphs with overlapping communities

Complex networks topologies present interesting and surprising properties, such as community structures, which can be exploited to optimize communication, to find new efficient and context-aware routing algorithms or simply to understand the dynamics and meaning of relationships among nodes. Complex networks are gaining more and more importance as a reference model and are a powerful interpretation tool for many different kinds of natural, biological and social networks, where directed relationships and contextual belonging of nodes to many different communities is a matter of fact. This paper starts from the definition of modularity function, given by M. Newman to evaluate the goodness of network community decompositions, and extends it to the more general case of directed graphs with overlapping community structures. Interesting properties of the proposed extension are discussed, a method for finding overlapping communities is proposed and results of its application to benchmark case-studies are reported. We also propose a new dataset which could be used as a reference benchmark for overlapping community structures identification.Comment: 22 pages, 11 figure