Analytical, numerical, and experimental investigation of a Luneburg lens system for directional cloaking

In this study, the design of a directional cloaking based on the Luneburg lens system is proposed and its operating principle is experimentally verified. The cloaking concept is analytically investigated via geometrical optics and numerically realized with the help of the finite-difference time-domain method. In order to benefit from its unique focusing and/or collimating characteristics of light, the Luneburg lens is used. We show that by the proper combination of Luneburg lenses in an array form, incident light bypasses the region between junctions of the lenses, i.e., the "dark zone." Hence, direct interaction of an object with propagating light is prevented if one places the object to be cloaked inside that dark zone. This effect is used for hiding an object which is made of a perfectly electric conductor material. In order to design an implementable cloaking device, the Luneburg lens is discretized into a photonic crystal structure having gradually varying air cylindrical holes in a dielectric material by using Maxwell Garnett effective medium approximations. Experimental verifications of the designed cloaking structure are performed at microwave frequencies of around 8 GHz. The proposed structure is fabricated by three-dimensional printing of dielectric polylactide material and a brass metallic alloy is utilized in place of the perfectly electric conductor material in microwave experiments. Good agreement between numerical and experimental results is found. © 2019 American Physical Society

Cognitive predictors of shallow-orthography spelling speed and accuracy in 6th grade children

Spelling accuracy and time course was investigated in a sample of 100 Norwegian 6th grade students completing a standardized spelling-to-dictation task. Students responded by keyboard with accurate recordings of response-onset latency (RT) and inter-keypress interval (IKI). We determined effects of a number of child-level cognitive ability factors, and of word-level factors—particularly the location within the word of a spelling challenge (e.g., letter doubling), if present. Spelling accuracy was predicted by word reading (word split) performance, non-word spelling accuracy, keyboard key-finding speed and short-term memory span. Word reading performance predicted accuracy just for words with spelling challenges. For correctly spelled words, RT was predicted by non-word spelling response time and by speed on a key-finding task, and mean IKI by non-verbal cognitive ability, word reading, non-word spelling response time, and key-finding speed. Compared to words with no challenge, mean IKI was shorter for words with an initial challenge and longer for words with a mid-word challenge. These findings suggest that spelling is not fully planned when typing commences, a hypothesis that is confirmed by the fact that IKI immediately before within word challenges were reliably longer than elsewhere within the same word. Taken together our findings imply that routine classroom spelling tests better capture student competence if they focus not only on accuracy but also on production time course

Vocabulary limitations undermine bilingual children’s reading comprehension despite bilingual cognitive strengths

Previous research reported bilingual cognitive strengths in working memory, executive function and novel-word learning skills (Bialystok in Psychol Bull 143:233–262, 2017; Kaushanskaya and Marian in Psychon Bull Rev 16:705–710, 2009). These skills should also support bilingual children’s vocabulary and reading development, yet bilingual children show weaknesses in their second language vocabulary and reading comprehension skills. Our primary aim was to clarify these seemingly paradoxical reports by investigating the cognitive strengths and weaknesses associated with both bilingual experience and reading comprehension in a single study. The participants were 102 English-speaking monolingual children and 104 Hindi/Urdu-English speaking bilingual children (mean age = 118.26 months, SD = 11.23 months) in the UK. We tested children’s vocabulary, working memory, executive function (cognitive inhibition, updating memory), novel-word learning, and reading skills. All testing was conducted in English. The findings supported the previous reports of bilingual cognitive strengths in working memory, novel-word learning and cognitive inhibition skills. However, despite their cognitive strengths and adequate word reading skills, the bilingual group displayed weaker reading comprehension than their monolingual peers. As anticipated, there was a direct association between bilingual children’s smaller English vocabulary size and underperformance on reading comprehension. Along with word reading, vocabulary was the most powerful unique predictor of reading comprehension. The effects of cognitive control skills on reading comprehension were mixed and mostly indirect through word reading skills. These relations were comparable across the monolingual and bilingual groups. Together, our findings highlighted the importance of clear educational policies on oral language assessment and support in our increasingly multilingual classrooms

Correlates of early reading comprehension skills: a componential analysis

This study had three main aims. First, we examined to what extent listening comprehension, vocabulary, grammatical skills and verbal short-term memory (VSTM) assessed prior to formal reading instruction explained individual differences in early reading comprehension levels. Second, we examined to what extent the three common component skills, namely vocabulary, grammar and VSTM explained the relationship between kindergarten listening comprehension and early reading comprehension levels. Third, we examined the relative contributions of word-reading and listening comprehension skills to early reading comprehension in Turkish. For this purpose, 56 Turkish-speaking children were followed from kindergarten (mean age = 67.7 months) into Grade 2 (mean age = 90.6 months). The relative role of kindergarten listening comprehension, vocabulary, VSTM and grammatical skills in later reading comprehension tended to vary across time, and they partly explained the relationship between listening comprehension and reading comprehension. Finally, as anticipated, listening comprehension, rather than word-reading , was found to play a more powerful role in children’s reading comprehension levels even during the early primary grades. These results contradicted those reported in English and can be explained by the rapid development of accurate word-reading skills due to the consistency of the grapheme–phoneme relationships of the Turkish orthography

The dynamics of narrative writing in primary grade children: Writing process factors predict story quality

In this study of third grade school children, we investigated the association between writing process measures recorded with key stroke logging and the final written product. Moreover, we examined the cognitive predictors of writing process and product measures. Analyses of key strokes showed that while most children spontaneously made local online revisions while writing, few revised previously written text. Children with good reading and spelling abilities made more online revisions than their peers. Two process factors, transcription fluency and online revision activity, contributed to explaining variance in narrative macrostructural quality and story length. As for cognitive predictors, spelling was the only factor that gave a unique contribution to explaining variance in writing process factors. Better spelling was associated with more revisions and faster transcription. The results show that developing writers’ ability to make online revisions in creative writing tasks is related to both the quality of the final written product and to individual literacy skills. More generally, the findings indicate that investigations of the dynamics of the writing process may provide insights into the factors that contribute to creative writing during early stages of literacy

COVID-19 Pandemic and the Global Perspective of Turkish Thoracic Society

It has been more than 3 months now since the first case of COVID-19 was reported in Turkey. Globally, the number of confirmed cases and deaths reached 9,653,048 and 491,128 respectively, as reported by 216 countries by June 27, 2020. Turkey had 1,396 new cases, 194,511 total cases, and 5,065 deaths by the same date. From the first case until today, the Turkish Thoracic Society (TTS) has been very proactive in educating doctors, increasing public awareness, undertaking academic studies, and assisting with public health policies. In the present report, social, academic, and management perspectives of the pandemic are presented under appropriate subtitles. During this critical public health crisis, TTS has once again demonstrated its readiness and constructive stance by supporting public health, healthcare workers, and the environment. This review summarizes the perspective of TTS on each aspect of the COVID-19 pandemic and casts light on its contributions.C1 [Kokturk, Nurdan] Gazi Univ, Sch Med, Dept Pulm Med, Ankara, Turkey.[Itil, Bahriye Oya; Ergan, Begum; Kilinc, Oguz; Simsek, Gokcen Omeroglu; Ucan, Eyup Sabri] Dokuz Eylul Univ, Sch Med, Dept Pulm Med, Izmir, Turkey.[Altinisik, Goksel] Pamukkale Univ, Sch Med, Dept Pulm Med, Denizli, Turkey.[Adiguzel, Nalan; Karkurt, Zuhal] Univ Hlth Sci, Istanbul Sureyyapas Chest Dis Training & Res Hosp, Dept Intens Care Unit Pulm Med, Istanbul, Turkey.[Akgun, Metin] Ataturk Univ, Dept Pulm Med, Sch Med, Erzurum, Turkey.[Akyildiz, Levent] Mem Dicle Hosp, Clin Pulm Med, Diyarbakir, Turkey.[Altin, Sedat; Akyil, Fatma Tokgoz] Univ Hlth Sci, Yedikule Chest Dis & Chest Surg Training & Res Ho, Dept Pulm Med, Istanbul, Turkey.[Arikan, Huseyin] Yuzuncu Yil Univ, Dursun Odaba Med Ctr, Med Intens Care Unit, Van, Turkey.[Ates, Gungor] Sultan Hosp, Dept Pulm Med, Diyarbakir, Turkey.[Ay, Pinar] Marmara Univ, Sch Med, Dept Publ Hlth, Istanbul, Turkey.[Aykac, Nilufer] Gayrettepe Florence Nightingale Hosp, Clin Pulm Med, Istanbul, Turkey.[Babayigit, Cenk] Mustafa Kemal Univ, Sch Med, Dept Pulm Med, Antakya, Turkey.[Bostan, Pinar] Istanbul Bilgi Univ, Sch Hlth Sci, Istanbul, Turkey.[Cinel, Guzin] Ankara Yildirim Beyazit Univ, Sch Med Ankara, Dept Pediat Pulmonol, Ankara, Turkey.[Calisir, Haluk Celaleddin] Yapi Kredi Hlth & Retirement Fdn, Istanbul, Turkey.[Celik, Pinar; Gultekin, Okkes; Havlucu, Yavuz; Yorgancioglu, A. Arzu] Celal Bayar Univ, Sch Med, Dept Pulm Med, Manisa, Turkey.[Cetinkaya, Pelin Duru] Univ Hlth Sci, Adana City Training & Res Hosp, Dept Pulm Med, Adana, Turkey.[Dagli, Elif] Turkish Thorac Soc, Ankara, Turkey.[Demir, Ahmet Ugur] Hacettepe Univ, Sch Med, Dept Pulm Med, Ankara, Turkey.[Demir, Canan; Sandal, Abdulsamet] Occupat & Environm Dis Hosp, Clin Occupat Dis, Ankara, Turkey.[Dikensoy, Oner] Acibadem Univ, Sch Med, Dept Pulm Med, Istanbul, Turkey.[Edis, Ebru Cakir] Trakya Univ, Sch Med, Dept Pulm Med, Edirne, Turkey.[Elbek, Osman] Kadikoy Florence Nightingale Hosp, Clin Pulm Med, Istanbul, Turkey.[Erdinc, Munevver; Goksel, Tuncay; Gurgun, Alev; Basoglu, Ozen K.; Sayiner, Abdullah] Ege Univ, Sch Med, Dept Pulm Med, Izmir, Turkey.[Eyuboglu, A. Fusun Oner] Baskent Univ, Sch Med, Dept Pulm Med, Ankara, Turkey.[Gemicioglu, Bilun] Istanbul Univ Cerrahpasa, Cerrahpasa Sch Med, Dept Pulm Dis, Istanbul, Turkey.[Gulhan, Erkmen] Ataturk Chest Dis & Thorac Surg Training & Res Ho, Dept Thorac Surg, Ankara, Turkey.[Gurkan, Canan Gunduz; Yildiz, Tekin] Univ Hlth Sci, Sureyyapasa Chest Dis & Thorac Surg Training & Re, Dept Pulm Med, Istanbul, Turkey.[Karakurt, Sait] Marmara Univ, Sch Med, Dept Intens Care Unit Pulm Med, Istanbul, Turkey.[Kocabas, Ali] Cukurova Univ, Sch Med, Dept Pulm Med, Adana, Turkey.[Kul, Seval] Gaziantep Univ, Sch Med, Dept Biostat, Gaziantep, Turkey.[Nayci, Sibel] Mersin Univ, Sch Med, Dept Pulm Med, Mersin, Turkey.[Ozkan, Metin] Ankara Mem Hosp, Clin Pulm Med, Ankara, Turkey.[Pinarer, Ozgun] Galatasaray Univ, Sch Engn, Istanbul, Turkey.[Salturk, Cuneyt] Istanbul Yeni Yuzyil Univ, Sch Med, Dept Pulm Med, Istanbul, Turkey.[Sen, Elif] Ankara Univ, Sch Med, Dept Pulm Med, Ankara, Turkey.[Karadag, Bulent Taner] Marmara Univ, Sch Med, Dept Pediat Pulmonol, Istanbul, Turkey.[Toreyin, Zehra Nur] Hlth Sci Univ, Adana City Training & Res Hosp, Dept Occupat Dis, Ankara, Turkey.[Varol, Ayhan] Kepez State Hosp, Clin Pulm Med, Antalya, Turkey.[Yasin, Yesim] Acibadem Univ, Sch Med, Dept Publ Hlth, Istanbul, Turkey.[Bayram, Hasan] Koc Univ, Sch Med, Dept Pulm Med, Istanbul, Turkey