bluuebunny/crossref_metadata_2025 huggingface dataset:
Primary school teachers perception of technological pedagogical content knowledge in online learning due to Covid 19
Authors: Makawawa Junita Cristi , Mustadi Ali , Septriwanto Jewish Van , Sampouw Falenthino , Najoan Roeth A.O
Published: March 2021

Primary school teachers need to have technological knowledge, pedagogical knowledge, and content knowledge in online teaching. TPACK is an integrative and transformative knowledge that teachers need to use technology effectively and efficiently in the classroom. This article investigates primary school teachers' perceptions of Technological Pedagogical Content Knowledge (TPACK) competencies in implementing online learning due to the pandemic COVID-19. The sample in this study were 117 primary school teachers in North Sulawesi province. The method used is a quantitative descriptive approach. Data was collected using a questionnaire on a Likert scale developed in Google Form. The results showed that most primary school teachers in North Sulawesi, Indonesia, already had TPACK competencies in online learning during the COVID-19 pandemic. Even so, TPACK competencies are in need to be improved in the abilities of TK and PK. The correlation results between the TPACK constructs also showed that the PK and TPK components had a significant effect on TPACK primary school teachers' perception of online learning. It was also found that there was no significant difference between gender and TPACK competency of primary school teachers.
Hubungan pedagogical content knowledge guru matematika dan prestasi belajar siswa sekolah menengah pertama
Authors: Barut Maria Evarista Oktaviane Barut , Wijaya Ariyadi , Retnawati Heri
Published: March 2021

Guru telah dikenal luas sebagai salah satu faktor penting yang mempengaruhi prestasi belajar siswa. Kompetensi guru, khususnya pengetahuannya, membantu guru untuk mengorganisasi­kan pem­belajaran yang efektif guna memfasilitasi keberhasilan belajar siswa. Salah satu jenis penge­tahuan yang penting dikuasai oleh guru adalah Pedagogical Content Knowledge (PCK). PCK merupakan kombinasi pengetahuan konten dan pedagogi yang mengarah pada bagaimana aspek-aspek tertentu dari materi pembelajaran diatur, diadaptasi, dan direpresentasikan untuk diterapkan di dalam proses pembelajaran. Penelitian ini bertujuan untuk mendeskripsikan ting­kat PCK guru matematika dan prestasi belajar siswa, serta menguji hubungan keduanya. Pene­litian ini adalah kuantitatif-korelasional dengan subjek penelitian 56 guru mate­matika dan 499 siswa SMP di Kabupaten Manggarai, Nusa Tenggara Timur. Data PCK guru dan prestasi siswa dikumpulkan menggunakan tes objektif yang telah dinyatakan valid dan reliabel. Data dianalisis menggunakan statistik deskriptif dan inferensial. Hasil penelitian mengungkapkan bahwa seba­gian besar guru memiliki PCK pada kategori rendah dan sebagian besar siswa memiliki prestasi belajar pada kategori rendah. Namun demikian, terdapat korelasi positif yang signifikan antara PCK guru mate­matika dan prestasi belajar siswa dengan kontribusi PCK guru terhadap prestasi belajar siswa sebesar 16,1%. Relationship between pedagogical content knowledge of mathematics teacher and learning achievement of junior high school studentsAbstractTeachers’ competence, especially their knowledge, helps them organize effective classrooms to facilitate students’ success. One of the essential knowledge that should be mastered by a teacher is Pedagogical Content Knowledge (PCK). PCK represents the combination of knowledge about content and pedagogy to understand how particular aspects of subject matter are organized, adapted, and represented for instruction. This study aimed to describe mathe­matics teachers’ PCK and students’ learning achievement as well as and between the two variables. The study was qualitative-correlational with 56 mathema­tics teachers and 499 senior high school students in Manggarai Regency, East Nusa Tenggara, Indonesia, as the subject. Both data of teachers’ PCK and students’ learning achievement were collected using validated and reliable objective tests. Data were analyzed using descriptive and inferen­tial statistics. The results indicated that most teachers have PCK in the low category, and most stu­dents have learning achievement in the low category. However, there was a positive correlation between teachers’ PCK and students’ learning achievement, with the contribution of the teachers’ PCK to students’ learning achieve­ment by 16,1%.
Pengembangan lembar kerja peserta didik (LKPD) berbasis problem-based learning (PBL) pada topik sudut
Authors: Abdillah Dandi Mifta , Astuti Dwi
Published: March 2021

Penelitian ini bertujuan untuk menghasilkan Lembar Kerja Peserta Didik (LKPD) berbasis Problem-Based Learning (PBL) pada topik sudut yang layak. Penelitian pengembangan ini mengadopsi model pengembangan ADDIE dengan tahapan meliputi Analysis, Design, Development, Implementation, dan Evaluation. Kualitas LKPD ditinjau dari penilaian ahli materi, ahli media, dan respon peserta didik. Instrumen penelitian yang digunakan adalah angket ahli materi, angket ahli media, dan angket respon peserta didik. LKPD diujicobakan di kelas VII SMP Muhammadiyah 1 Yogyakarta dengan subjek sebanyak 32 peserta didik. LKPD yang dikembangkan memuat aktivitas pembelajaran sesuai langkah PBL, menyajikan masalah yang berkaitan dengan kehidupan sehari-hari di awal pembelajaran, dan dapat digunakan dalam pembelajaran online. Ditinjau dari aspek materi, LKPD dinilai baik dengan rerata skor penilaian oleh ahli materi yaitu 4,00. Ditinjau dari aspek media, LKPD dinilai baik dengan skor penilaian oleh ahli media sebesar 3,6. Respon peserta didik terhadap penggunaan LKPD termasuk pada kategori baik dengan rerata skor penilaian sebesar 4,05. Dapat disimpulkan bahwa LKPD berbasis PBL untuk SMP kelas VII pada topik sudut layak digunakan dalam pelaksanaan pembelajaran matematika. Development of a students' worksheet based on problem-based learning (PBL) on the topic of anglesAbstractThis study aimed to produce a students’ worksheet or Lembar Kerja Peserta Didik (LKPD) based on Problem-Based Learning (PBL) on the topic of angles, which were feasible. This development research adopts the ADDIE development model with stages including Analysis, Design, Development, Implementation, and Evaluation. The quality of LKPD was viewed from the assessment of material experts, media experts, and students’ responses. The instrument used was a material expert questionnaire, a media expert questionnaire, and a students’ response questionnaire. LKPD was piloted on 32 seventh grade students of private junior high schools, namely SMP Muhammadiyah 1 Yogyakarta, Indonesia. The developed LKPD contained learning activities according to PBL steps, presented problems related to everyday life at the beginning of learning, and could be used in online learning. In terms of the material aspect, LKPD was considered good with an average score of assessment by material experts, namely 4.00. In terms of the media aspect, LKPD was considered good with a score of 3.6 by media experts. Students’ responses to the use of LKPD were included in the good category with an average score of assessment of 4.05. It could be concluded that the PBL-based LKPD for seventh-grade junior high school students on the topic of angles was feasible for use in the implementation of mathematics learning.
Accuracy of an Artificial Intelligence System for Cancer Clinical Trial Eligibility Screening: Retrospective Pilot Study
Authors: Haddad Tufia , Helgeson Jane M , Pomerleau Katharine E , Preininger Anita M , Roebuck M Christopher , Dankwa-Mullan Irene , Jackson Gretchen Purcell , Goetz Matthew P
Published: March 2021

Background

Screening patients for eligibility for clinical trials is labor intensive. It requires abstraction of data elements from multiple components of the longitudinal health record and matching them to inclusion and exclusion criteria for each trial. Artificial intelligence (AI) systems have been developed to improve the efficiency and accuracy of this process.

Objective

This study aims to evaluate the ability of an AI clinical decision support system (CDSS) to identify eligible patients for a set of clinical trials.

Methods

This study included the deidentified data from a cohort of patients with breast cancer seen at the medical oncology clinic of an academic medical center between May and July 2017 and assessed patient eligibility for 4 breast cancer clinical trials. CDSS eligibility screening performance was validated against manual screening. Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value for eligibility determinations were calculated. Disagreements between manual screeners and the CDSS were examined to identify sources of discrepancies. Interrater reliability between manual reviewers was analyzed using Cohen (pairwise) and Fleiss (three-way) κ, and the significance of differences was determined by Wilcoxon signed-rank test.

Results

In total, 318 patients with breast cancer were included. Interrater reliability for manual screening ranged from 0.60-0.77, indicating substantial agreement. The overall accuracy of breast cancer trial eligibility determinations by the CDSS was 87.6%. CDSS sensitivity was 81.1% and specificity was 89%.

Conclusions

The AI CDSS in this study demonstrated accuracy, sensitivity, and specificity of greater than 80% in determining the eligibility of patients for breast cancer clinical trials. CDSSs can accurately exclude ineligible patients for clinical trials and offer the potential to increase screening efficiency and accuracy. Additional research is needed to explore whether increased efficiency in screening and trial matching translates to improvements in trial enrollment, accruals, feasibility assessments, and cost.
Reducing social loafing in online brand communities: Insights from social exchange theory
Authors: Hou Rujing , Zhang Chubing
Published: March 2021

We applied social exchange theory to our investigation of how different types of social support (informational, emotional, esteem, network) influence social loafing in online brand communities through psychological ownership and community commitment. We used a questionnaire to collect
data from 315 participants, then tested the research model with partial least squares structural equation modeling. Results show that the four types of social support had different effects on psychological ownership and community commitment, which, in turn, influenced social loafing. Further,
community commitment mediated the effect of psychological ownership on social loafing. Our results extend social loafing theory and provide guidelines for reducing social loafing in online brand communities.
Successful surgical treatment approach for mitral valve vegetation of infective endocarditis after severe soft tissue infection with mediastinitis.
Authors: Uchida Kenichiro , Takahashi Yosuke , Shibata Toshihiko , Mizobata Yasumitsu
Published: March 2021

An independent 59-year-old Asian man presented with a current history of
fever, left shoulder pain and unconsciousness.Contrast-enhanced computed
tomography revealed mediastinitis with expansive fluid collection.
During the mediastinitis treatment, huge vegetation was sequentially
confirmed at the annulus of the mitral valve and was successfully
treated via small right thoracotomy.
Idiopathic Atraumatic Splenic Rupture, an underestimated cause of acute abdomen
Authors: Sah Ganesh , Adhikari Shankar , Ghimire Bikal , Maharjan Narendra
Published: March 2021

Atraumatic splenic rupture is an uncommon but important clinical entity.
We report a case of young healthy male who had pain abdomen secondary to
atraumatic rupture of spleen. On thorough workup, no conditions
affecting the spleen was found and the patient was suspected to have
idiopathic rupture.
Validity and reliability of ROPScore scoring method to predict the severity of retinopathy of prematurity in premature infants
Authors: Gulkas Samet , Ozcan Yasin , GUMUS Huseyin
Published: March 2021

Abstract Purpose: To assess the accuracy and efficacy of ROPScore
scoring system an ancillary method to predict the severity of
retinopathy of prematurity (ROP) in very low birth weight (VLBW)
premature infants. Methods: The medical records of 131 premature babies
having a birth weight  1500 gram and gestational age (GA) ≤ 30 weeks
were included in this study. The ROPScore was calculated for each baby
at six weeks of life using an Excel spreadsheet (Microsoft®). Area under
curve (AUC) analysis was used in both any stage of ROP and type-1
(severe) ROP to ascertain the cut-off points for the scoring model.
Sensitivity, specificity, positive predictive values (PPV) and negative
predictive values (NPV) of the scoring system with the calibrated
cut-off points were analyzed. Results: The sensitivity of the ROPScore
scoring system was 88.5% ( 95% CI 79-94) and 100% (95% CI 82-100)
was for predicting any stage and type-1 retinopathy of prematurity,
respectively. The PPV and NPV of the models were 62% and 74.1% for any
stage of ROP and those of were 50% and 100% for type-1 ROP,
respectively. In ROC analysis, the mean AUCs of ROPScore model was
statistically significant compared than BW and GA for predicting type -1
ROP (p < 0.001). Conclusion: This study indicated that
ROPScore scoring model with customized cutoff levels might be a useful
method for early prediction of premature retinopathy, particularly in
type-1 (severe) ROP. In addition, this model may also reduce the number
of eye examinations which are essential for detecting the retinopathy of
prematurity
Hidroelektrik Santrallarda Bakım Strateji Optimizasyonu için Hiyerarşik Bir Karar Modeli Önerisi
Authors: YAZICI Emre , ÖZCAN Evrencan , ALAKAŞ Hacı Mehmet , EREN Tamer
Published: March 2021

Günümüzde enerji talebi her geçen gün artmaktadır. Enerji arzını sağlayan tesisler artan bu talebe kesintisiz bir şekilde cevap verecek politikalar ve uygulamalar geliştirmektedirler. Enerjide sürekliliği sağlamakta etkili olan unsurlardan biri de enerjinin üretildiği santralların bakım stratejilerini arzı kesintiye uğratmayacak şekilde belirlemektir. Bu çalışmada, bir hidroelektrik santralda en kritik elektriksel ekipmanın bulunması ve bu ekipman için bakım stratejisinin seçimi amaçlanmıştır. Bu çalışma iki aşamadan oluşmaktadır. İlk olarak en kritik elektriksel ekipman belirlenmiştir. Ekipmanların sıralanmasında kullanılan kriterlerin ağırlıklarının belirlenmesinde Pisagor Bulanık Analitik Hiyerarşi Prosesi (PBAHP) kullanılmıştır. Alternatiflerin sıralanmasında ise, PBAHP yöntemi ile TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) yöntemi entegre edilmiştir. En kritik elektriksel ekipman olarak belirlenen generatör ekipmanı için en uygun bakım stratejisi revizyon bakım olarak belirlenmiştir.
Ergonomics Assessment and Redesign of Helicopter Transmission Assembly Fixture Using Digital Human Models
Authors: KOÇ Ömer , TOP Neslihan , ELDEM Cengiz , GÖKÇE Harun , ŞAHİN İsmail
Published: March 2021

Digital Human Modeling (DHM) is an integral part of computerized engineering studies. In this study, an assembly fixture has been designed that will be used in the assembly of the helicopter transmission and it has been analyzed for compliance of ergonomic conditions using DHM technique. Rapid Upper Limb Assessment (RULA) and Biomechanical Motion Analyses (BMA) were used in the analyses. The ergonomic competence of the human was analyzed empirically for two different assembly conditions. The assembly fixture redesigned has significant ergonomic advantages over the conventional ones. According to the analyses was provided that 79.6 % advantage in compression loading and 94.3 % advantage in moment loading, which occurs on the L4-L5 lumbar vertebra discs. As a result, it was revealed that the ergonomic assembly fixture designed for workers to work in a more comfortable and safe manner was suitable for its purpose.
Editorial: Teachers’ Work in a Pandemic
Authors: Benade Leon , Devine Nesta , Teschers Christoph
Published: March 2021

N/A
Simulation of the Hydrodynamic Field in Nhat Le Estuary, Quang Binh Province
Authors: Loc Nguyen Xuan , Dinh Thuc Dang , Vinh Quang Trang
Published: March 2021

Hydrodynamic field is the primary research problem of all studies on coastal estuarine areas. Over the years, there have been many studies on Nhat Le estuary's region (Quang Binh). Still, these studies have not focused on simulating the characteristics of the hydrodynamics of this area. This study will present the ability to apply a mathematical model to simulate hydrodynamic fields for the region of Nhat Le estuary and Quang Binh sea by constructing the MIKE 21 model set based on the actual measurement database by the Center for Environmental Fluid Dynamics implemented in 2018. Through the calculation scenarios under different conditions, the longshore current mainly consists of Southeast - Northwest (especially with NE waves, the current direction is Northwest - Southeast) with current speed mostly in the range of 0.1 - 0.4 m/s. In estuarine areas, river flows have complicated developments, including many component flows. In the dry season, the river flow is not strong and is dominated by changes in the tide phase, withdrawal in a day. There are days of high flood flow in the flood season, overwhelming the tidal currents; the maximum flow velocity at the door can reach more than 6 m/s. Waves in the southwest monsoon season are relatively small, about 0.25 - 0.6 m; while the waves in the Northeast monsoon season are quite large and very strong during the storm, but when the depth is about -3 to -4 m, the wave height decreases sharply, spreading to the door. In particular, when there are floods in the river, the waves that propagate through this depth will almost calm.
Application of Green Nanocomposite to Adsorb Cadmium ion in Wastewater
Authors: Thu Ha Hoang , Dinh Minh Tran , Minh Nguyet Ha
Published: March 2021

Under to the development of the industrialization, people have polluted the water source with chemicals and wastes from factories and enterprises. These chemicals are not treated and discharged directly to the natural environment, especially heavy metals. Cadmium and its compounds are released to the environment from different sources of waste, such as metal, alloy and metal plating, and Cd-Ni batteries, which clearly showed a danger to the human health. In this work, silicon oxide nanoparticles (SiO2) functionalized with polyaniline (PANI) polymer, then C2H5OH-SiO2/PANI (CSP) was synthesized by dispersion process in ultrasound sonication by ethanol solution. CSP were successfully synthesized and determined by several characterizations such as FTIR, SEM, TEM and BET. Based on the practical data, the Cd(II) adsorption was followed by Langmuir adsorption isotherms, and the pseudo-second order adsorption kinetic. CSP has obtained the Cd maximum adsorption capacity of 301.23 mg g-1, which is higher than the previous reported adsorbents. Cd(II) adsorption by CSP is desired at pH 6, reaction time of 150 min, initial concentration at 300 mg L-1, and weight of 0.6 g. Adsorption data show that pH is one of the most important factor in Cd(II) adsorption due to the formation of surface complexes between Cd2+ and the functional groups of CSP such as hydroxyl group (OH-), silanol (Si-OH), amine (–NH2), quinoid imine [C=N–] and benzenoid amine [–NH–].
Urban Classification Using Multi-temporal Sentinel-1 Data Based On Coherence Characteristics
Authors: Hang Le Minh , Anh Tuan Tran
Published: March 2021

Classification urban features plays an important part in monitoring and development planning of the area. Optical remote sensing data is currently used in study land use/land cover. However, optical remote sensing data are affected by clouds and weather. Hence, it is difficult to update information. Sentinel-1 is the satellite mission which conducted by the European Space Agency (ESA). Sentinel-1 is composed of two satellites, Sentinel-1A and Sentinel-1B which carried C-band Synthetic Aperture Radar (SAR) instrument, 10m spatial resolution and provided free of charge. SAR images, which is an active microwave data, is not affected by weather, day and night. In this article, the authors present the experimental results of using coherence technique of two SAR images acquised at different times to classify urban features. The classification accuracy by using VV and VH polarization images were respectively 89% and 93%. VH polarization image data used in classification urban feature is better than VV polarization image.
Moisture Transfer Finite Element Modeling with Soil-Water Characteristic Curve-Based Parameters and its Application to Nhan Co Red Mud Basin Slope
Authors: Hoang Nguyen Van , Viet Hung Hoang , Van Dung Pham
Published: March 2021

Since the year of 2017 landslides at the red mud basins in Nhan Co alumina factory, Dak Nong province have been occurring during the rainy seasons. The change of the soil physical and mechanical parameters due to rainwater infiltration has been considered as the main factor of the slope instability. The soil cohesion and angle of internal friction depend very much on the soil moisture: soil with a lower moisture content has a higher shearing strength than that with higher moisture content. The finite element modeling of moisture transfer in unsaturated soils through the relationship between soil moisture, soil suction, unsaturated permeability and soil-moisture dispersivity is capable of accurately predicting the wetting front development. The element sizes and time steps have been selected based on detailed analysis of analytical error estimation and on the numerical simulations with different element sizes numerical simulation errors. Soil samples had been taken and the soil different suctions and corresponding soil moisture values have been determined in the laboratory. The soil water characteristic curve (SWCC) parameters (a, n and m) have been determined by the best fitting using the least squared error method. The hydraulic conductivity of the saturated soil, one of the key input parameters was also determined. The results of the application to the study area's slope has shown that the wetting front depth can be up to 8 meters for 90 days of moisture transfer due to the rainwater infiltration The wetting front depth and the length of the intermediate part of the moisture distribution curve have increased with the infiltration time. The soil moisture distribution with a depth is an essential information to have soil strength parameters for the slope stability analyses. The slope stability analysis with the soil shear strength parameters which are strictly corresponding with the moisture change would provide the most accurate and reliable slope stability results and provide more reliable slope stabilization solutions.
A relação fala/escrita em dados não-convencionais de escrita infantil
Authors: Chacon Lourenço
Published: March 2021

Tendo como principal preocupação a relação fala/escrita na escrita infantil, o objetivo do presente estudo foi investigar flutuações no registro ortográfico de palavras nesse tipo de escrita. Trata-se de flutuações que ocorreram no interior de um mesmo texto e que envolveram os constituintes prosódicos grupo clítico e palavra fonológica. Os dados foram extraídos de produções escritas de crianças brasileiras que cursavam as três séries iniciais do Ensino Fundamental I, que compõem o Ciclo de Alfabetização. Os resultados mostraram que as flutuações deixam indícios da ancoragem das crianças, simultaneamente, em características prosódicas de enunciados falados e em características das convenções ortográficas presentes em enunciados escritos. Assim, ao sinalizarem sua ancoragem em práticas de oralidade e de letramento, as flutuações mostram que as relações fala/escrita detectadas na escrita infantil são constitutivas dessa escrita. A ancoragem das flutuações em características dessas práticas mostrou, ainda, as não-coincidências das palavras consigo mesmas, sobretudo por apontarem para relações que uma mesma estrutura prosódica da língua mantém, na enunciação escrita, com as estruturas prosódicas mais amplas que as recobrem. Mostrou, por fim, traços da subjetividade e da historicidade dos escreventes.
O ÊXODO DOS JOVENS RURAIS, A TEORIA DO BEM VIVER E A RESISTÊNCIA DA COMUNIDADE REMANESCENTE DE QUILOMBO DO IBICUÍ D’ARMADA, NA FRONTEIRA DO RS
Authors: Madrid Rosemeri Da Silva , Gonçalves Margarete Lopez
Published: March 2021

O presente artigo tem por objetivo compreender os processos de resistência e perenidade das famílias do território quilombola do Ibicuí d’Armada, localizado no município de Sant’Ana do Livramento na fronteira oeste do RS. Para atingir este objetivo foi adotada abordagem qualitativa, com entrevistas com um grupo de jovens moradores da comunidade e a liderança local. Tomando por base as teorias das capacitações e a teoria do Bem Viver, conclui-se que a comunidade remanescente quilombola possui extrema riqueza cultural e histórica para o município, possuindo potencial ainda não explorado para alavancar desenvolvimento rural, cultural, social e humano, mas que, se não houver ações efetivas neste sentido, o território corre sério risco de se extinguir.
O PLANEJAMENTO URBANÍSTICO E AMBIENTAL NA BACIA DO RIO CAMBORIÚ E CONTÍGUAS: A INTERDEPENDÊNCIA ENTRE DOIS MUNICÍPIOS
Authors: Meirinho André Furlan , Dacol Kelli Cristina , Turnes Valério Alécio
Published: March 2021

Este artigo tem por objetivo apresentar uma análise do cenário de crises, disputas e resistências que envolve as comunidades tradicionais pesqueiras e quilombolas da Ilha de Maré, Salvador – Bahia. Uma das temáticas que tem ganhado relevante destaque, nas últimas décadas, refere-se às inúmeras disputas e conflitos territoriais que as comunidades tradicionais pesqueiras têm vivenciado nos seus territórios. No estado da Bahia esse cenário envolve cerca de 600 comunidades e mais de 100 mil famílias, dentre as quais destacamos aquelas situadas na Ilha de Maré, localizada na Baía de Todos os Santos (BTS). Possuidoras de um amplo conhecimento sobre as águas, os manguezais e os pescados da BTS, a relação de apropriação desenvolvida por essas comunidades com a natureza é caracterizada por extremos laços de identidade, pertencimento e, principalmente, respeito, onde são desenvolvidos valores simbólicos e materiais que asseguram o seu modo de vida e configuram suas territorialidades. Territorialidades que têm sido intensamente ameaçadas e, em alguns casos, destruídas, pelo modelo de desenvolvimento historicamente empregado no local. Observa-se que os espaços que eram de uso das comunidades, aos poucos, foram sendo ocupados, delimitados e controlados por novas e distintas atividades (aquícola, portuária, metalúrgica, petroquímica, turística etc.), originando inúmeras crises sociais, econômicas, ambientais, além das disputas territoriais. Para o desenvolvimento da análise, recorremos metodologicamente às técnicas da pesquisa participante com a utilização dos seguintes instrumentos: levantamento bibliográfico, documental e, principalmente, de campo, com a realização de reuniões, participação em audiências públicas, oficinas de geografia e cartografia, mapeamento e georreferenciamento dos territórios em disputa.

 
A non-distillability criterion for secret correlations
Authors: Masanes L. , Winter A.
Published: March 2021

Within entanglement theory there are criteria which certify that some quantum states cannot be distilled into pure entanglement. An example is the positive partial transposition criterion. Here we present, for the first time, the analogous thing for secret correlations. We introduce a computable criterion which certifies that a probability distribution between two honest parties and an eavesdropper cannot be (asymptotically) distilled into a secret key. The existence of non-distillable correlations with positive secrecy cost, also known as bound information, is an open question. This criterion may be the key for finding bound information. However, if it turns out that this criterion does not detect bound information, then, a very interesting consequence follows: any distribution with positive secrecy cost can increase the secrecy content of another distribution. In other words, all correlations with positive secrecy cost constitute a useful resource.
C_3, semi-Clifford and genralized semi-Clifford operations
Authors: Beigi S. , Shor P.W.
Published: March 2021

Fault-tolerant quantum computation is a basic problem in quantum computation, and teleportation is one of the main techniques in this theory. Using teleportation on stabilizer codes, the most well-known quantum codes, Pauli gates and Clifford operators can be applied fault-tolerantly. Indeed, this technique can be generalized for an extended set of gates, the so called ${\mathcal{C}}_k$ hierarchy gates, introduced by Gottesman and Chuang (Nature, 402, 390-392). ${\mathcal{C}}_k$ gates are a generalization of Clifford operators, but our knowledge of these sets is not as rich as our knowledge of Clifford gates. Zeng et al. in (Phys. Rev. A 77, 042313) raise the question of the relation between ${\mathcal{C}}_k$ hierarchy and the set of semi-Clifford and generalized semi-Clifford operators. They conjecture that any ${\mathcal{C}}_k$ gate is a generalized semi-Clifford operator. In this paper, we prove this conjecture for $k=3$. Using the techniques that we develop, we obtain more insight on how to characterize ${\mathcal{C}}_3$ gates. Indeed, the more we understand ${\mathcal{C}}_3$, the more intuition we have on ${\mathcal{C}}_k$, $k\geq 4$, and then we have a way of attacking the conjecture for larger $k$.
Quantum universality by state distillationIndirect quantum control for finite-dimensional coupled systems
Authors: Nie J. , Fu H.C. , Yi X.X.
Published: March 2021

We present a new analysis on the quantum control for a quantum system coupled to a quantum probe. This analysis is based on the coherent control for the quantum system and a hypothesis that the probe can be prepared in specified initial states. The results show that a quantum system can be manipulated by probe state-dependent coherent control. In this sense, the present analysis provides a new control scheme which combines the coherent control and state preparation technology.
Relationship between the n-tangle and the residual entanglement of even n qubits
Authors: Li Xiangrong , Li Dafa
Published: March 2021

We show that for even $n$ qubits,$\ n$-tangle is the square of the SLOCC polynomial invariant of degree 2. We find that the $n$-tangle is not the residual entanglement for any even $n\geq 4$\ qubits. We give a necessary and sufficient condition for the vanishing of the concurrence $C_{1(2...n)}$. The condition implies that the concurrence $C_{1(2...n)}$ is always positive for any entangled states while the $n$-tangle vanishes for some entangled states. We argue that for even $n$\ qubits, the concurrence $ C_{1(2...n)}$\ is equal to or greater than the $n$-tangle.\ Further, we reveal that the residual entanglement is a partial measure for product states of any $n$ qubits while the $n$-tangle is multiplicative for some product states.
Symmetric states: local unitary equivalence via stabilizers
Authors: Cenci Curt D. , Lyons David W. , Snyder Laura M. , Walck Scott N.
Published: March 2021

We classify local unitary equivalence classes of symmetric states via a classification of their local unitary stabilizer subgroups. For states whose local unitary stabilizer groups have a positive number of continuous degrees of freedom, the classification is exhaustive. We show that local unitary stabilizer groups with no continuous degrees of freedom are isomorphic to finite subgroups of the rotation group $SO(3)$, and give examples of states with discrete stabilizers.
A lower bound on the value of entangled binary games
Authors: Beigi Salman
Published: March 2021

A two-player one-round binary game consists of two cooperative players who each replies by one bit to a message that he receives privately; they win the game if both questions and answers satisfy some predetermined property. A game is called entangled if the players are allowed to share a priori entanglement. It is well-known that the maximum winning probability (value) of entangled XOR-games (binary games in which the predetermined property depends only on the XOR of the two output bits) can be computed by a semidefinite program. In this paper we extend this result in the following sense; if a binary game is uniform, meaning that in an optimal strategy the marginal distributions of the output of each player are uniform, then its entangled value can be efficiently computed by a semidefinite program. We also introduce a lower bound on the entangled value of a general two-player one-round game; this bound depends on the size of the output set of each player and can be computed by a semidefinite program. In particular, we show that if the game is binary, $\omega_q$ is its entangled value, and $\omega_{sdp}$ is the optimum value of the corresponding semidefinite program, then $0.68\,\omega_{sdp} < \omega_q \leq \omega_{sdp}$.
When is there a multipartite maximum entangled state?
Authors: Duan Runyao , Shi Yaoyun
Published: March 2021

For a multipartite quantum system of the dimension $d_1\otimes d_2\otimes\cdots\otimes d_n$, where $d_1\ge d_2\ge\cdots\ge d_n\ge2$, is there an entangled state {\em maximum} in the sense that all other states in the system can be obtained from the state through local quantum operations and classical communications (LOCC)? When $d_1\ge\Pi_{i=2}^n d_i$, such state exists. We show that this condition is also necessary. Our proof, somewhat surprisingly, uses results from algebraic complexity theory.
High-fidelity universal quantum gates
Authors: Li Ran , Gaitan Frank
Published: March 2021

Twisted rapid passage is a type of non-adiabatic rapid passage that generates controllable quantum interference effects that were first observed experimentally in $2003$. It is shown that twisted rapid passage sweeps can be used to implement a universal set of quantum gates $\calGU$ that operate with high-fidelity. The gate set $\calGU$ consists of the Hadamard and NOT gates, together with variants of the phase, $\pi /8$, and controlled-phase gates. For each gate $g$ in $\calGU$, sweep parameter values are provided which simulations indicate will produce a unitary operation that approximates $g$ with error probability$P_{e} < 10^{-4}$. Note that \textit{all\/} gates in $\calGU$ are implemented using a \textit{single family\/} of control-field, and the error probability for each gate falls below the rough-and-ready estimate for the accuracy threshold $P_{a}\sim 10^{-4}$.
Geometric measure of quantum discord under decoherence
Authors: Lu Xiao-Ming , Xi Zhengjun , Sun Zhe , Wang Xiaoguang
Published: March 2021

The dynamics of a geometric measure of the quantum discord (GMQD) under decoherence is investigated. We show that the GMQD of a two-qubit state can be alternatively obtained through the singular values of a $3\times4$ matrix whose elements are the expectation values of Pauli matrices of the two qubits. By using Heisenberg picture, the analytic results of the GMQD is obtained for three typical kinds of the quantum decoherence channels. We compare the dynamics of the GMQD with that of the quantum discord and of entanglement. We show that a sudden change in the decay rate of the GMQD does not always imply that of the quantum discord, and vice versa. We also give a general analysis on the sudden change in behavior and find that at least for the Bell diagonal states, the sudden changes in decay rates of the GMQD and that of the quantum discord occur simultaneously.
The quantum query complexity of certification
Authors: Ambainis A. , Childs A.M. , Le Gall F. , Tani S.
Published: March 2021

We study the quantum query complexity of finding a certificate for a d-regular, k-level balanced \nand formula. We show that the query complexity is $\tilde\Theta(d^{(k+1)/2})$ for 0-certificates, and $\tilde\Theta(d^{k/2})$ for 1-certificates. In particular, this shows that the zero-error quantum query complexity of evaluating such formulas is $\tilde O(d^{(k+1)/2})$. Our lower bound relies on the fact that the quantum adversary method obeys a direct sum theorem.
Quantum information processing with quantum zeno many-body dynamics
Authors: Monras A. , Romero-Isart O.
Published: March 2021

We show how the quantum Zeno effect can be exploited to control quantum many-body dynamics for quantum information and computation purposes. In particular, we consider a one dimensional array of three level systems interacting via a nearest-neighbour interaction. By encoding the qubit on two levels and using simple projective frequent measurements yielding the quantum Zeno effect, we demonstrate how to implement a well defined quantum register, quantum state transfer on demand, universal two-qubit gates and two-qubit parity measurements. Thus, we argue that the main ingredients for universal quantum computation can be achieved in a spin chain with an {\em always-on} and {\em constant} many-body Hamiltonian. We also show some possible modifications of the initially assumed dynamics in order to create maximally entangled qubit pairs and single qubit gates.
Computable constraints on entanglement-sharing of multipartite quantum states
Authors: Ou Y.-C. , Byrd M.S.
Published: March 2021

\Negativity is regarded as an important measure of entanglement in quantum information theory. In contrast to other measures of entanglement, it is easily computable for bipartite states in arbitrary dimensions. In this paper, based on the negativity and realignment, we provide a set of entanglement-sharing constraints for multipartite states, where the entanglement is not necessarily limited to bipartite and pure states, thus aiding in the quantification of constraints for entanglement-sharing. These may find applications in studying many-body systems.
Classical simulation of quantum computation, the gottesman-Knill theorem, and slightly beyond
Authors: Van den Nest M.
Published: March 2021

We study classical simulation of quantum computation, taking the Gottesman-Knill theorem as a starting point. We show how each Clifford circuit can be reduced to an equivalent, manifestly simulatable circuit (normal form). This provides a simple proof of the Gottesman-Knill theorem without resorting to stabilizer techniques. The normal form highlights why Clifford circuits have such limited computational power in spite of their high entangling power. At the same time, the normal form shows how the classical simulation of Clifford circuits fits into the standard way of embedding classical computation into the quantum circuit model. This leads to simple extensions of Clifford circuits which are classically simulatable. These circuits can be efficiently simulated by classical sampling (``weak simulation'') even though the problem of exactly computing the outcomes of measurements for these circuits (``strong simulation'') is proved to be $\#\mathbf{P}$-complete---thus showing that there is a separation between weak and strong classical simulation of quantum computation.
Single-photon entanglement concentration for long-distance quantum communication
Authors: Sheng Y.-B. , Deng F.-G. , Zhou H.-Y.
Published: March 2021

We present a single-photon entanglement concentration protocol for long-distance quantum communication with quantum nondemolition detector. It is the first concentration protocol for single-photon entangled states and it dose not require the two parties of quantum communication to know the accurate information about the coefficient $\alpha$ and $\beta$ of the less entangled states. Also, it does not resort to sophisticated single-photon detectors, which makes this protocol more feasible in current experiments. Moreover, it can be iterated to get a higher efficiency and yield. All these advantages maybe make this protocol have more practical applications in long-distance quantum communication and quantum internet.
Finding conjugate stabilizer subgroups in $\PSL$ and related groups
Authors: Denney DA. , Moore C. , Russell A.
Published: March 2021

We reduce a case of the hidden subgroup problem (HSP) in $\SL$, $\PSL$, and $\PGL$, three related families of finite groups of Lie type, to efficiently solvable HSPs in the affine group $\AGL$. These groups act on projective space in an ``almost'' 3-transitive way, and we use this fact in each group to distinguish conjugates of its Borel (upper triangular) subgroup, which is also the stabilizer subgroup of an element of projective space. Our observation is mainly group-theoretic, and as such breaks little new ground in quantum algorithms. Nonetheless, these appear to be the first positive results on the HSP in finite simple groups such as $\PSL$.
Upper bounds on the noise threshold for fault-tolerant quantum computing
Authors: Kempe J. , Regev O. , Unger F. , de Wolf R.
Published: March 2021

We prove new upper bounds on the tolerable level of noise in a quantum circuit. We consider circuits consisting of unitary $k$-qubit gates each of whose input wires is subject to depolarizing noise of strength $p$, as well as arbitrary one-qubit gates that are essentially noise-free. We assume that the output of the circuit is the result of measuring some designated qubit in the final state. Our main result is that for $p>1-\Theta(1/\sqrt{k})$, the output of any such circuit of large enough depth is essentially independent of its input, thereby making the circuit useless. For the important special case of $k=2$, our bound is $p>35.7\%$. Moreover, if the only allowed gate on more than one qubit is the two-qubit CNOT gate, then our bound becomes $29.3\%$. These bounds on $p$ are numerically better than previous bounds, yet are incomparable because of the somewhat different circuit model that we are using. Our main technique is the use of a Pauli basis decomposition, in which the effects of depolarizing noise are very easy to describe.
On quantum-classical equivalence for composed communication problems
Authors: Sherstov A.A.
Published: March 2021

An open problem in communication complexity proposed by several authors is to prove that for every Boolean function $f,$ the task of computing $f(x\wedge y)$ has polynomially related classical and quantum bounded-error complexities. We solve a variant of this question. For every $f,$ we prove that the task of computing, on input \mbox{$x$ and $y,$} \emph{both} of the quantities $f(x\wedge y)$ and $f(x\vee y)$ has polynomially related classical and quantum bounded-error complexities. We further show that the quantum bounded-error complexity is polynomially related to the classical deterministic complexity and the block sensitivity of $f.$ This result holds regardless of prior entanglement.
Threshold error rates for the toric and planar codes
Authors: Wang D.S. , Fowler A.G. , Stephens A.M. , Hollenberg L.C.L.
Published: March 2021

The planar code scheme for quantum computation features a 2d array of nearest-neighbor coupled qubits yet claims a threshold error rate approaching 1\%. This result was obtained for the toric code, from which the planar code is derived, and surpasses all other known codes restricted to 2d nearest-neighbor architectures by several orders of magnitude. We describe in detail an error correction procedure for the toric and planar codes, which is based on polynomial-time graph matching techniques and is efficiently implementable as the classical feed-forward processing step in a real quantum computer. By applying one and two qubit depolarizing errors of equal probability $p$, we determine the threshold error rates for the two codes (differing only in their boundary conditions) for both ideal and non-ideal syndrome extraction scenarios. We verify that the toric code has an asymptotic threshold of $p_{\textrm{th}} = 15.5\%$ under ideal syndrome extraction, and $p_{\textrm{th}} = 7.8 \times 10^{-3}$ for the non-ideal case, in agreement with \cite{Raus07d}. Simulations of the planar code indicate that the threshold is close to that of the toric code.
Quantum Fisher information for superpositions of spin states
Authors: Xiong H.-N. , Ma J. , Liu W.-F. , Wang X.
Published: March 2021

In terms of quantum Fisher information, a quantity $\chi^{2}$ was introduced by Pezz\'{e} and Smerzi, which is a multiparticle entanglement measure, and provides a necessary and sufficient condition for sub-shot-noise phase estimation sensitivity. We derive a general expression of $\chi ^{2}$ for arbitrary symmetric multiqubit states with nonzero mean spins. It is shown that the entangled symmetric states are useful for phase sensitivity beyond the shot-noise limit. Using the expression, we explicitly examine a series of superpositions of spin states. We find that the superpositions of Dicke states perform better than Dicke states themselves in phase esitmation. Although the spin coherent states themselves only have a shot-noise limit phase sensitivity, their superpositions may reach the Heisenberg limit.
One dimensional quantum walks with memory
Authors: Mc Gettrick M.
Published: March 2021

We investigate the quantum versions of a one-dimensional random walk, whose corresponding Markov Chain is of order 2. This corresponds to the walk having a memory of one previous step. We derive the amplitudes and probabilities for these walks, and point out how they differ from both classical random walks, and quantum walks without memory.
Privacidad frente al uso de drones con fines periodísticos. Marco regulador de Estados Unidos y Europa
Authors: Aguado-Guadalupe Guadalupe
Published: March 2021

El artículo analiza la repercusión en la actividad periodística de las medidas reguladoras aprobadas por parte de Estados Unidos y Europa para proteger la privacidad frente al uso de drones. Se estudian las similitudes y diferencias entre las disposiciones adoptadas. Se observa que en Estados Unidos se opta por recomendaciones, donde prevalece la voluntariedad del usuario del dron frente al derecho de terceros a la privacidad. Si bien hay excepciones, como los casos de los estados de Texas y California, donde se considera un delito contra la privacidad el uso de drones sin la debida autorización. En Europa, la normativa es aplicable a todos los países miembros, y el sistema es más garantista, considerando los principios de necesidad y transparencia.
El estado de la investigación en los Trabajos Fin de Máster en periodismo deportivo en España
Authors: Rojas Torrijos José Luis
Published: March 2021

Este artículo, de carácter exploratorio y descriptivo, realiza un diagnóstico general sobre el estado de la docencia y la investigación en periodismo deportivo dentro de los másteres de la especialidad que ofertan las universidades españolas. Tomando esta radiografía como punto de partida, evalúa en qué medida la producción de los Trabajos Fin de Máster responde a objetivos de investigación o a fines profesionales en función del plan de estudios y perfil de profesorado de esas titulaciones. Para ello se ha procedido a una exhaustiva recogida de datos de los ocho centros universitarios que han impartido másteres de la especialidad en los dos últimos cursos académicos, entre 2017 y 2019. Así se han analizado el volumen, las temáticas y las tipologías de TFM desarrollados. La recogida de datos se ha complementado con cuestionarios y consultas a directores y coordinadores de los másteres objeto de estudio. Los resultados confirman que los TFM en los másteres de periodismo deportivo, al ser todos excepto uno títulos propios y al contar en un alto porcentaje con profesores procedentes del ámbito profesional con menor formación investigadora, apenas inciden en teorías y metodologías ni en temáticas que abran nuevas vías hacia la producción científica en este campo de especialización