149 research outputs found
collected from South and South-eastern regions of Turkey
A total of 45 lizards (Acanthodactylus harranensis [n = 15], Acanthodacthylus schreiberi [n = 9] and Mesalina brevirostris [n = 21]) were collected from South and Southeastern Regions of Turkey and examined for helminth fauna. Acanthodactylus harranensis harbored 1 species of Nematoda (Skrjabinodon sp.), 1 species of Cestoda (Oochoristica tuberculata) and 1 species of Acanthocephala (Centrorhynchus sp. [cystacanth]). Acanthodactylus schreiberi harbored unidentified cysticercoids. Mesalina brevirostris harbored 1 species of Nematoda (Spauligodon saxicolae). All lizards represents new host records for the helminths reported in this study
Single-Loop Opto-Electronic Oscillator at 10.4 GHz with a Cascaded Microstrip Bandpass Filter Configuration
The opto-electronic oscillator is a well-known microwave photonic device that produces high-frequency signals in the microwave range. One of the main advantages of the opto-electronic oscillator is that it produces high-frequency signals with low phase noise thanks to the resonator's properties. In most cases the opto-electronic oscillator faces the problem of generating side modes besides the oscillation signal due to non-ideal filtering. In this paper we propose a solution for the additional suppression of these undesired harmonics using a combination of two slightly detuned bandpass microstrip filters. We report an improvement for the side-mode suppression ratio about 8.3 dB with a single-loop 90-m-long opto-electronic oscillator at 10.4 GHz
Adjustable testing setup for a single-loop optoelectronic oscillator with an electrical bandpass filter
In this paper we present a novel method to measure the free spectral range (FSR) and side-mode suppression ratio (SMSR) of an optoelectronic oscillator (OEO) by adjusting the optical fiber length using an optical path selector and signal source analyzer. We have designed a setup for a single-loop OEO operating around 5 GHz and 10 GHz that features electrical bandpass filters for side-mode suppression. The proposed approach makes it possible to evaluate the FSR and SMSR of OEOs with different optical fiber paths without requiring the changing of fiber spools or optical connectors. This approach could be useful for testbeds that investigate the implementation of an OEO in a 5G radio access network
Domain-wall depinning assisted by pure spin currents
We study the depinning of domain walls by pure diffusive spin currents in a
nonlocal spin valve structure based on two ferromagnetic permalloy elements
with copper as the nonmagnetic spin conduit. The injected spin current is
absorbed by the second permalloy structure with a domain wall and from the
dependence of the wall depinning field on the spin current density we find an
efficiency of 6*10^{-14}T/(A/m^2), which is more than an order of magnitude
larger than for conventional current induced domain wall motion. Theoretically
we reproduce this high efficiency, which arises from the surface torques
exerted by the absorbed spin current that lead to efficient depinning.Comment: 11 pages, 3 figures, accepted for publication in Phys. Rev. Let
Shovels and Swords: How realistic and fantastical themes affect children's word learning
Cataloged from PDF version of article.Research has shown that storybooks and play sessions help preschool children learn vocabulary, thereby benefiting their language and school readiness skills. But the kind of content that leads to optimal vocabulary learning – realistic or fantastical – remains largely unexplored. We investigate this issue as part of a large-scale study of vocabulary learning in low-income classrooms. Preschoolers (N = 154) learned 20 new words over the course of a two-week intervention. These words were taught using either realistic (e.g., farms) or fantastical (e.g., dragons) storybooks and toys. Children learned the new words in both conditions, and their comprehension knowledge did not differ across conditions. However, children who engaged in stories and play with a fantastical theme showed significantly greater gains in their production knowledge. Reasons for and implications of this result are discussed
Narrative performance, peer group culture, and narrative development in a preschool classroom
Introduction This chapter uses the analysis of a preschool storytelling and story-acting practice to explore some of the ways that peer-oriented symbolic activities and peer group culture can serve as valuable contexts for promoting young children’s narrative development. In the process, it suggests the need to rethink, refine, and broaden the conceptions of the “social context” of development now used by most research in language socialization and development. There is a substantial and growing body of work on the role of social context in language development (Hoff 2006). In practice, most research on this subject has focused on delineating and analyzing various forms of adult–child interaction, usually dyadic, in which an adult caregiver transmits information, provides cultural models, and in other ways instructs, guides, corrects, and “scaffolds” the efforts of the less capable child. By comparison, research on the complementary role of peers in socialization and development has been, as Blum-Kulka and Snow (2004: 292) put it, relatively “peripheral and non-cumulative.” As the present volume helps to demonstrate, that situation has gradually been changing. But with some notable exceptions, the perspectives informing peer-oriented developmental research often remain limited in important respects. Even when interaction between children is studied, it is usually assimilated to the one-way expert–novice model, with an older sibling or other peer taking on the “expert” role. And both adult-oriented and peer-oriented research tend to reduce the social context of development, explicitly or in effect, to interactions between individuals and their direct consequences. © Cambridge University Press 2014
Phenylalanine Tolerance over Time in Phenylketonuria: A Systematic Review and Meta-Analysis
In phenylketonuria (PKU), natural protein tolerance is defined as the maximum natural protein intake maintaining a blood phenylalanine (Phe) concentration within a target therapeutic range. Tolerance is affected by several factors, and it may differ throughout a person’s lifespan. Data on lifelong Phe/natural protein tolerance are limited and mostly reported in studies with low subject numbers. This systematic review aimed to investigate how Phe/natural protein tolerance changes from birth to adulthood in well-controlled patients with PKU on a Phe-restricted diet. Five electronic databases were searched for articles published until July 2020. From a total of 1334 results, 37 articles met the eligibility criteria (n = 2464 patients), and 18 were included in the meta-analysis. The mean Phe (mg/day) and natural protein (g/day) intake gradually increased from birth until 6 y (at the age of 6 months, the mean Phe intake was 267 mg/day, and natural protein intake was 5.4 g/day; at the age of 5 y, the mean Phe intake was 377 mg/day, and the natural protein intake was 8.9 g/day). However, an increase in Phe/natural protein tolerance was more apparent at the beginning of late childhood and was >1.5-fold that of the Phe tolerance in early childhood. During the pubertal growth spurt, the mean natural protein/Phe tolerance was approximately three times higher than in the first year of life, reaching a mean Phe intake of 709 mg/day and a mean natural protein intake of 18 g/day. Post adolescence, a pooled analysis could only be performed for natural protein intake. The mean natural protein tolerance reached its highest (32.4 g/day) point at the age of 17 y and remained consistent (31.6 g/day) in adulthood, but limited data were available. The results of the meta-analysis showed that Phe/natural protein tolerance (expressed as mg or g per day) increases with age, particularly at the beginning of puberty, and reaches its highest level at the end of adolescence. This needs to be interpreted with caution as limited data were available in adult patients. There was also a high degree of heterogeneity between studies due to differences in sample size, the severity of PKU, and target therapeutic levels for blood Phe control.</jats:p
Giant enhancement of spin accumulation and long-distance spin precession in metallic lateral spin valves
The nonlocal spin injection in lateral spin valves is highly expected to be
an effective method to generate a pure spin current for potential spintronic
application. However, the spin valve voltage, which decides the magnitude of
the spin current flowing into an additional ferromagnetic wire, is typically of
the order of 1 {\mu}V. Here we show that lateral spin valves with low resistive
NiFe/MgO/Ag junctions enable the efficient spin injection with high applied
current density, which leads to the spin valve voltage increased hundredfold.
Hanle effect measurements demonstrate a long-distance collective 2-pi spin
precession along a 6 {\mu}m long Ag wire. These results suggest a route to
faster and manipulable spin transport for the development of pure spin current
based memory, logic and sensing devices.Comment: 23 pages, 4 figure
- …