bluuebunny/crossref_metadata_2025 huggingface dataset:
Autism Spectrum Disorder during Five Years in Eastern Libya and Food Choices to Improve the Conditions
Authors: Ageila Amal
Published: February 2020

Healthy diet choices may improve health and skills of children with autism. The presentstudy aimed to illustrate the frequency of autism spectrum disorder in Libya, to demonstrateeffect of sex and age variables on children with autism and explain a specific dietary programwith important recommendations to progress the abilities and skills. 275 suspected cases ofautism spectrum disorder were documented during 2012 to 2017 in Tobruk NationalAssociation for Autism. Only, 241 cases (183 males and 58 females) aged from 3 to 20 yearsold were diagnosed to confirm the incidence of autism or not and were statistically analyzed.Among 241 cases, 167 (69.3%) (121 males and 46 females) only have autism spectrumdisorder, whereas, 74 cases (30.7%) have no autism condition. Results showed that boys wereapproximately more three times than girls to have autism. There was statistically significantassociation between males and females for getting autism spectrum disorder (P= 0.019).Autism can affect both genders, but it may be more specific for males than females. Also,results revealed that there was no evidence of a statistically significant relationship betweenthe incidence of autism in males and females according to their age (p = 0.218). This pointups that there is no specific autism incidence according to age because autism may occurfrom the birth. There is no treatment for autism, but mixed factors may help to improve theconditions such as introducing adequate nutrition to the child with a combined effort ofcountry and institution with parents to enhance the skills, abilities and activities of childrenwith autism.
تطبيق ابحاث المخ والأعصاب في سيكولوجية التعلم والتعليم
Authors: امتوبل د. عائشة سعيد حمد
Published: February 2020

إن الربط بين التعلم والدماغ آخر ما استجد في ميدان علم الأعصاب وفيه من المرونة لإستدخال أي جديد في أوساط المعلمين وكل من هو مهتم بالابتكار والتطوير، ونتيجة للتطورات المتلاحقة فنحن بحاجة إلى هذا النوع من التعلم لذا سوف نتناول الأساليب الحديثة في التعلم بدلًا من الجو الروتيني الذي يرغمنا على الحفظ الآلي كما هو متبع في الطريقة التقليدية. وسيتم التطرق نظريا إلى البنية الأساسية للدماغ، وكيف يحدث التعلم، وعرض مراحل التعلم المستند إلى الدماغ ،و أهم التطبيقات العملية لأبحاث الدماغ، وبعض الاستراتيجيات، وتوضيح أهم العناصر الأساسية لترجمة أبحاث الدماغ عمليا في غرفة الصف، وننتهي بعرض بعض التوصيات للمهتمين بالعملية التعليمية.
Knowledge and Awareness about Human Papillomavirus, Cervical Cancer and HPV Vaccine among College Students in Tripoli
Authors: Jerbi Dr. Rehab, S , Benhamza Dr. Mawadda, F. , Mousa Dr. Arij
Published: February 2020

Background: In the absence of any nationwide cervical screening program, cancer of cervix remains a major public health problem in Libya. Cervical cancer prevention programs vary widely by country and could be completely improved by new technologies. Whichever, validated screening method is chosen, broad coverage and complete follow-up of abnormalities are the key requirements for reducing the incidence of cervical cancer by screening and prophylactic human papillomavirus (HPV) vaccination, which has been shown to be highly effective at preventing infection. Moreover, the public’s knowledge and awareness are the high priority for cervical cancer control and women need to understand the link between HPV and cervical cancer to make appropriate prevention strategies. Objectives: To assess student’s awareness of HPV and knowledge about its link to cervical cancer. Methods: Analyzed cross-sectional data from 300 Tripoli university female students in 2016, ages 18 to 27 years old responding to a questionnaire, which was designed to tape the information about HPV, cancer cervix awareness, Pap test and HPV vaccine. Result: Only 3% of participants were married and no one had ever had screening for cervical cancer. Overall medical students’ knowledge was more than other students. About 60% of students never heard about HPV, 38% knew it caused cervical cancer; knowledge that HPV was sexually transmitted and caused abnormal Pap tests was low (34% and 32%, respectively). Also, this study reported that 60% of students aware of Pap smear test, only 37% of them aware of cervical cancer risk factors, 74% were aware of cervical cancer symptoms. While 65.3% knew HPV vaccine. Conclusions: Generally, awareness about HPV and cancer cervix among college students are low. There is need for a countrywide strong knowledge base about cervical cancer so that public can easily identify the early symptoms of the disease and take preventive measures.
تصور مقترح لمسارات إرشادية لتأصيل الجودة بمؤسسات رياض الأطفال في ليبيا بنغازي أنموذج
Authors: المنفي مريم محمد عبد العزيز المنفي
Published: February 2020

تناولت الدراسة تصور مقترح بعنوان "مسارات إرشادية لتأصيل الجودة بمؤسسات رياض الأطفال في ليبيا" بنغازي نموذجا. حيث تهدف الدراسة بشكل رئيسي إلى توضيح مدى ضرورة تطبيق معايير الجودة داخل المؤسسات التعليمية، ا وستخدام المنهج الوصفي التحليلي بالاعتماد على الأبحاث السابقة والمؤتمرات والتراث الأدبي المتعلق بمعايير الجودة.
منع التكدس والاحتياج بسوق العمل بواسطة منظومة كمبيوتر تربط الجامعات بالجهات العامة
Authors: سعد عبدالحميد المهدي ادريس
Published: February 2020

اعداد هائلة لباحثين عن عمل لا احتياج لهم, وفي نفس الوقت احتياج السوق لتخصصات لا يوجد عدد كاف منهم. هكذا سوق العاملين في ليبيا. ولا يحفى على احد ان اعداد الباحثين عن العمل من خريجو الجامعات الذين لا احتياج لعددهم الزائد عن حده يتراكم لسنوات قد ترهق الباحث وتحبطه للشهادة التي يحملها, وايضا في النهاية يتم تعيينهم ارضاء لهم بدون النظر الى مصلحة الوطن من موازنة في الاحتياج من عدمه. ونرى ايضا استمرارية في ذلك بحيث اصبح ذلك آلية ثابتة: وهى جامعة تُ رج بدون دراسات وربط دقيق مع سوق العمل و قوى عاملة تتراكم لديها المشكلة وتصبح هي محط الاسئلة والمسؤولية في حال تأخر التعيينات. فالربط يتم بين المجتمع بجاهته العامة والتي مركزها مكاتب القوى العمالة بالمدن مع الجامعات التي هي بدورها تؤهل الطالب وتجهزه لممارسة تصصه. في هذه الورقة تم اعداد منظومة ببرنامج الاكسيس والفيجوال بيسك وهما برامج لتصميم المنظومات وتمت التصميم لاستخدامه بسهولة كوسيلة ربط بين الجامعة والجهات العامة والتي يمثلها مكتب القوى العاملة. بحيثيكون من المنظومة ثلاث نسخ: نسخة لدى اجهزة الحواسيب الخاصة بالجهات أي جميع جهات المدينة, و نسخة لدى مكتب القوى العاملة و النسخة الاخيرة لدى مكتب المسجل العام بالجامعة. تُربط بسهولة هذه المنظومات المختلفة الاماكن ببرنامج الاس كيو ال SQL وهو يربط المنظومات الثلاثة عند ادخال أي بيانات. كل جهة تُعبئ احتياجها بالمنظومة على تصور اربعسنوات قادمة حسب احتياجها لتخصص معين والعدد لذلك التخصص. وفي النهاية تتحول هذه الاحتياجات الى اعداد والتخصصات المقابلة لتلك الاعداد. العدد لكل كلية هدفه يساعد في تحديد سقف القبول للطلبة لتلك الكلية. اما العدد لكل تصص هذا ستستعين به الكلية عند التنسيب للأقسام.
عوامل التطور العمران لمدينٌة طرابلس الغرب خلال فترة حكم الاسرة القرمانليةٌ ( 1711 - 1835)م
Authors: البركي مصطفى فرج علي , صديقٌ روزيةٌ صديقٌ , الزمان د. أزمول بن قمر
Published: February 2020

يقٌاس مدى ازدهار وتحضر المدن بمدى نمو وتطور عمرانها, ومن أجل ذلك نجد أن الحكام والملوك كانوا شديدٌي الحرص على الاهتمام بمدنهم لتظهر بؤجمل منظر وأبهى حلة, لأن في عظمتهاتخل دٌاً لأسمائهم وتبج لٌاً لذكراهم, بيدٌ أن ذلك كان مقرونباً ببعض الظروف الت كانت تعيشٌها المدن آنذاك وهو ما أصطلح على تسميتٌه بعوامل التطور العمران ,ً ومن خلال هذا البحث سنتناول العوامل - التي أثرت على مدينٌة طرابلس الغرب وتطور عمرانها خلال فترة حكم الاسرة القرمانليةٌ ( 1711 - 1835 م). وتهدف الدراسة إلى تتبع تلك العوامل ومدى تؤثيرٌها على بنيةٌ المدينٌة وتطورها العمران ,ً سواءً أكان هذا التؤثيرٌ إ جٌابياًٌ أو سلبياًٌ, وتكمن أهميةٌ الدراسة في كون فكرتها لم تطبق على مدينٌة طرابلس من قبل على الرغم من تطبيقٌها على العديدٌ من المدن العربيةٌ والإسلاميةٌ, ومن جهة أخرى فإن هذه الدراسة تستهدف فترة حكم الاسرة القرمانليةٌ التي تعد من الفترات المهمة في تاريخٌ مدينٌة طرابلس لأن المدينٌة خلالها أضحت عاصمة لولايةٌ مستقلة عن الدولة العثمانيةٌ بعدما كانت تابعة تبعيةٌ مباشرة للسلطان العثمان ,ً وتكمن أهميةٌ فترة القرمانلينٌٌ أ ضٌاً يف توفر المعلومات عنها مقارنة بالفترات السابقة واللاحقة لها, وتعد هذه الدراسة جزءً من دراسة متكاملة تشمل تطور عمران مدينٌة طرابلس سيتٌم نشرها لاحقاً إن شاء الله.
Exploring the Natural Match between Communicative and Cooperative Learning Strategies
Authors: Suweekar Najla Ali
Published: February 2020

It has been widely known that Communicative Language Teaching CLT has emerged as a result to the objection of the traditional methods of teaching foreign languages, in terms of activating Cooperative Language Learning CLL, as opposed to memorizing grammatical and lexical items. While CLT and CLL represent two faces for the same coin, the aim of this paper is to follow the nature of both communicative and cooperative approaches. It will present the importance of focusing on communicative processes and cooperative tasks to enhance learning of a foreign language in a higher education setting. The researcher observed and experimented two classes contained 41 students of English language at two different universities in western Libya. As based on the results, the current lecturing teaching method is not suitable for upgrading students' achievement levels, whereas cooperative learning offers the necessary skills for them to interact communicatively, promote academically and feel positively. The study results might be used to give further implications for the creation of new university group work activities, and developing or updating the existing university teaching methods.
أساليبٌ التنشئة الاجتماعيةٌ ودورها في التفاعل الاجتماعي الد مٌقراطي لدى الأبناء - دراسة ميدٌانيةٌ على عينٌة من تلاميذٌ الشق الثاني من التعليمٌ الاساس - بمدينٌة المرج
Authors: موسى د. نبيلٌ عيسٌى جبريلٌ , عبدالكريمٌ د. عادل محمد علي
Published: February 2020

تمحورت الدراسة حول موضوع "أساليبٌ التنشبة الاجتماعيةٌ ودورها في التفاعل الاجتماعي الد يمٌقراطي لدى الأبناء" دراسة ميدٌانيةٌ على عينٌة من تلاميذٌ الشق الثاني من التعليمٌ الاساس بمدينٌة المرج،وانطلقت الدراسة من هدف عام تمثل في التعرف على دور أساليبٌ التنشبة الاجتماعيةٌ في التفاعل الاجتماع الدبمٌقراطي لدى الأبناء، وقد طبقت الدراسة على عينٌة بلغ قوامها 60 طالباً وطالبة، وبما أن توزيعٌ مفردات العينٌة تم باتباع اجراءات العينٌة العشوائيةٌ الطبقيةٌ النسبة على أربع مدارس تم اختياٌرها بشكل عشوائي من مجتمع الدراسة؛ إلا أن اختياٌر مفردات العينٌة من الاربع مداس تم من خلال اجراءات العينٌة العشوائيةٌ المنتظمة،
الموازنة المائية للتربة في الجبل الأخضر
Authors: إسماعيل د. أنور فتح الله , هابيل د. أحمد يوسف
Published: February 2020

في هذه الدراسة تم محاولة تقدير الموازنة المائية للتربة في مناطق الزراعة المطرية بالجبل الأخضر حيث تم حساب الموازنة بأسلوب ثورنثويت المعدل لستة مواقع بالجبل الأخضر وذلك لإبراز التوزع المكاني والتغير الشهري لفترات العجز والفائض المائي . وقد تم تقدير عنصر التبخر نتح الممكن وفقاً لنموذج تيرك الملائم لمناخ منطقة الدراسة وأظهرت النتائج أفضلية للجزء الأوسط منالجبل الأخضر المواجه لساحل البحر المتوسط والذي تمثله محطة شحات وما حولها كمنطقة يسود فيها محتوى الطين في التربة وتمتاز بأكبر وأطول فترة فائض مائي وأقل فترة عجز شهري ،كما ارتبطت معدلات التبخر نتح في نطاق السفوح الجنوبية بعلاقة طردية قوية جداً مع محتوى التربة الرملي مما انعكس في سيادة سلبية للموازنة المائية تمثلت في استغراق فترة العجز المائي لمعظم موسم الأمطار.
The Importance of Embedding Authenticity in the EFL Pedagogy
Authors: Othman Najwa Muftah Mohamed
Published: February 2020

Recent research and learning theory provide a lot of thoughts and strategies to endorse learner-centered, practical and useful learning environments. Authenticity should be a fundamental factor in the educational pedagogy especially in the EFL classrooms. Authenticity in language teaching involves not only authentic materials, but also authentic tasks and learning environment. Characteristics of authenticity are mainly related to learner’s motivation, learner independency, communicative ability. This paper stands as a response to the following question: How much is it important to use authentic materials when teaching English Language Learners (ELLs)? The paper also provides some examples of utilizing authenticity in learning environment. Then, it comes to the conclusion that it is crucial and possible to make full use of authenticity in language teaching.
عوامل التخلف الاجتماعي في الدول النامية
Authors: محمد أ. اشرف سليمان بوبكر , محمد أ. عبد الفتاح عبد الرحيم جبريل , الذرعاني د. عبدالسلام ادم علي , شعيب د. سالم ابوبكر محمد
Published: February 2020

اشتملت الورقة على مجموعة من النقاط الرئيسية فيما يتعلق بعوامل التخلف الاجتماعي في الدول النامية,واتخذت تسلل فكري في سرد عناصرها انطلاقا من التعريف بمفهوم التخلف الاجتماعي, بشكل عام ومن ثم عرض عناصره واهمخصائصه في هذه المجتمعات المتخلفة, كما تطرقت لمؤشرات التخلف الاجتماعي في الدول النامية, واهم المراحل التي شكلتالانطلاقة الاساسية لها, بالإضافة الى استعراض مفهوم الدول المتخلفة استعراض ابرز خصائصها , واهم التحديات الاجتماعيةالتي تعترض خطط التنمية الاجتماعية فيها, وابراز تأثير الصعوبات الاقتصادية والثقافية على الوضع التنموي في البلدان المتخلفة ,واخيرا التركيز على الشروط اللازمة لضمان نجاح خطط التنمية الاجتماعية في هذه الدول التي تحاول جاهدة الخروج من دائرةالتخلف الاجتماعي والاقتصادي .
VIOLENCIA OBSTÉTRICA: ANÁLISIS SITUACIONAL DE AMÉRICA LATINA
Authors: Montero Espina Leonardo , Ayala Servín José , Torres Romero Anthon
Published: February 2020

Carta editor: Una revisión de la situación y bibliografía de la violencia obstétrica en Latino América, una práctica común en los servicios públicos de varios países latinoamericanos y que debería estar condenada por todos los miembros del gremio médico.
O livro didático e suas contribuições para o ensino religioso
Authors: Silva Maria da Penha Lima da , Pinheiro Danielle Ventura de Lima
Published: February 2020

O livro didático é uma importante ferramenta de trabalho utilizada pelos professores e manuseada diariamente pelos alunos. No caso do Ensino Religioso, este material didático vem sofrendo mudanças ao longo dos anos, pois sai, paulatinamente, de um caráter prosélito para uma leitura plural do fenômeno religioso, consequência de um esforço contínuo de instituições como o Fórum Nacional Permanente do Ensino Religioso (FONAPER), que vem dando um novo direcionamento para as abordagens que precisam ser desenvolvidas em sala de aula tomando como base os Parâmetros Curriculares Nacionais do Ensino Religioso (PCNER). Estudar o livro didático para o  Ensino Religioso, atentando para suas peculiaridades, limitações e capacidade de incentivo à leitura é o objetivo deste trabalho. Para tanto, partiu-se de um estudo de autores que atentam para essas questões próprias deste recurso metodológico, como também se refletiu sobre as abordagens mais específicas, destinadas ao Ensino Religioso.  De antemão, o estudo propiciou a apresentação tanto das especificidades do livro didático nesta área do conhecimento, suas utilizações nem sempre adequadas ao que o aluno precisa como também foi capaz de ressaltar os seus pontos positivos partindo, especialmente, da obra de Carniato (2009) como apta a atender ao que vem sendo refletido pelos profissionais da área sobre a proposta para o Ensino Religioso.
Tracking two pleasures
Authors: Brielmann Aenne A. , Pelli Denis G.
Published: February 2020

Can people track several pleasures? In everyday life, pleasing stimuli rarely appear in isolation. Yet, experiments on aesthetic pleasure usually present only one image at a time. Here, we ask whether people can reliably report the pleasure of either of two images seen in a single glimpse. Participants (N = 13 in the original; +25 in the preregistered replication) viewed 36 Open Affective Standardized Image Set (OASIS) images that span the entire range of pleasure and beauty. On each trial, the observer saw two images, side by side, for 200 ms. An arrow cue pointed, randomly, left, right, or bidirectionally. Left or right indicated which image (the target) to rate while ignoring the other (the distractor); bidirectional requested rating the combined pleasure of both images. In half the blocks, the cue came before the images (precuing). Otherwise, it came after (postcuing). Precuing allowed the observer to ignore the distractor, while postcuing demanded tracking both images. Finally, we obtained single-pleasure ratings for each image shown alone. Our replication confirms the original study. People have unbiased access to their felt pleasure from each image and the average of both. Furthermore, the variance of the observer’s report is similar whether reporting the pleasure of one image or the average pleasure of two. The undiminished variance for reports of the average pleasure of two images indicates either that the underlying pleasure variances are highly correlated, or, more likely, that the variance arises in the common reporting process. In brief, observers can faithfully track at least two visual pleasures.
Simultaneous tracking of psychophysical detection thresholds and evoked potentials to study nociceptive processing
Authors: van den Berg Boudewijn , Doll Robert J. , Mentink Alexander L.H. , Siebenga Pieter S. , Groeneveld Geert J. , Buitenweg Jan R.
Published: February 2020

Measuring altered nociceptive processing involved in chronic pain is difficult due to a lack of objective methods. Potential methods to characterize human nociceptive processing involve measuring neurophysiological activity and psychophysical responses to well-defined stimuli. To reliably measure neurophysiological activity in response to nociceptive stimulation using EEG, synchronized activation of nerve fibers and a large number of stimuli are required. On the other hand, to reliably measure psychophysical detection thresholds, selection of stimulus amplitudes around the detection threshold and many stimulus–response pairs are required. Combining the two techniques helps in quantifying the properties of nociceptive processing related to detected and non-detected stimuli around the detection threshold.

The two techniques were combined in an experiment including 20 healthy participants to study the effect of intra-epidermal electrical stimulus properties (i.e. amplitude, single- or double-pulse and trial number) on the detection thresholds and vertex potentials. Generalized mixed regression and linear mixed regression were used to quantify the psychophysical detection probability and neurophysiological EEG responses, respectively.

It was shown that the detection probability is significantly modulated by the stimulus amplitude, trial number, and the interaction between stimulus type and amplitude. Furthermore, EEG responses were significantly modulated by stimulus detection and trial number. Hence, we successfully demonstrated the possibility to simultaneously obtain information on psychophysical and neurophysiological properties of nociceptive processing. These results warrant further investigation of the potential of this method to observe altered nociceptive processing.
Multiwavelength Emission from Galactic Jets: The Case of the Microquasar SS433
Authors: Sudoh Takahiro , Inoue Yoshiyuki , Khangulyan Dmitry
Published: February 2020

SS433 is a Galactic microquasar with powerful jets, where very-high-energy particles are produced. We study particle acceleration in the jets of SS433 through the use of recent multiwavelength data from radio to TeV gamma-ray. We first present a general framework for the particle acceleration, cooling, and transport in relativistic jets. We then apply this to two X-ray knots in the jets of SS433, focusing on leptonic emission. Our detailed treatment of particle transport and evolution produces substantially different predictions from previous papers. For both regions, our model can account for the multiwavelength data except for the GeV data. This suggests that GeV emission is mostly from different regions and/or mechanisms. We find that the acceleration process should be efficient, which could be realized by diffusive shock acceleration close to the Bohm limit. Provided that protons are accelerated at the same efficiency as electrons, our results imply that SS433 is a PeVatron, i.e., can accelerate protons beyond a PeV. Future hard X-ray and MeV gamma-ray observations can critically test our models by detecting the spectral turnover or cutoff.
Asymmetries of Heavy Elements in the Young Supernova Remnant Cassiopeia A
Authors: Holland-Ashford Tyler , Lopez Laura A. , Auchettl Katie
Published: February 2020

Supernova remnants (SNRs) offer the means to study supernovae (SNe) long after the original explosion and can provide a unique insight into the mechanism that governs these energetic events. In this work, we examine the morphologies of X-ray emission from different elements found in the youngest known core-collapse SNR in the Milky Way, Cassiopeia A. The heaviest elements exhibit the highest levels of asymmetry, which we relate to the burning process that created the elements and their proximity to the center of explosion. Our findings support recent model predictions that the material closest to the source of explosion will reflect the asymmetries inherent to the SN mechanism. Additionally, we find that the heaviest elements are moving more directly opposed to the neutron star (NS) than the lighter elements. This result is consistent with NS kicks arising from ejecta asymmetries.
The Molecular Outflow from R Mon*
Authors: Sandell Göran , Vacca W. , Bouscasse L. , Güsten R.
Published: February 2020

We have mapped the young Herbig Be star R Mon in CO(3–2) and 13CO(3–2) with Atacama Pathfinder EXperiment in Chile and analyzed unpublished Herschel images. We find that R Mon is embedded in a small cloud with a gas temperature of ∼20 K and a total mass of ∼70

. We confirm that R Mon drives a bipolar molecular outflow, which is blueshifted north of R Mon. The blueshifted outflow has excavated the molecular cloud north of R Mon, creating the reflection nebula NGC 2261 and filling it with high-velocity gas. At “high” velocities the orientation of the outflow is approximately n–s, which agrees with the optical jet, suggesting that the accretion disk is e–w. The outflow velocities are modest, ±9 km s−1. The outflow is rather massive, ∼0.56

in the blueshifted outflow lobe. The outflow is completely optically thick in CO(3–2) toward R Mon, indicating that its envelope is ≲2000 au. The mass of the accretion disk and surrounding envelope determined from an isothermal graybody fit is ∼0.34

. We estimate a mass-loss rate of ∼(1–3) × 10−5

yr−1, corresponding to an accretion rate of (1–9) × 10−6

yr−1. We find that R Mon has bolometric luminosity of <1000

. R Mon is still in an active accretion phase, contributing to the observed luminosity. Hence, R Mon cannot be a B0 star; it must be a late B star or even an early A star.
Electrons in the Young Solar Wind: First Results from the Parker Solar Probe
Authors: Halekas J. S. , Whittlesey P. , Larson D. E. , McGinnis D. , Maksimovic M. , Berthomier M. , Kasper J. C. , Case A. W. , Korreck K. E. , Stevens M. L. , Klein K. G. , Bale S. D. , MacDowall R. J. , Pulupa M. P. , Malaspina D. M. , Goetz K. , Harvey P. R.
Published: February 2020

The Solar Wind Electrons Alphas and Protons experiment on the Parker Solar Probe (PSP) mission measures the three-dimensional electron velocity distribution function. We derive the parameters of the core, halo, and strahl populations utilizing a combination of fitting to model distributions and numerical integration for ∼100,000 electron distributions measured near the Sun on the first two PSP orbits, which reached heliocentric distances as small as ∼0.17 au. As expected, the electron core density and temperature increase with decreasing heliocentric distance, while the ratio of electron thermal pressure to magnetic pressure (β

e
) decreases. These quantities have radial scaling consistent with previous observations farther from the Sun, with superposed variations associated with different solar wind streams. The density in the strahl also increases; however, the density of the halo plateaus and even decreases at perihelion, leading to a large strahl/halo ratio near the Sun. As at greater heliocentric distances, the core has a sunward drift relative to the proton frame, which balances the current carried by the strahl, satisfying the zero-current condition necessary to maintain quasi-neutrality. Many characteristics of the electron distributions near perihelion have trends with solar wind flow speed, β

e
, and/or collisional age. Near the Sun, some trends not clearly seen at 1 au become apparent, including anticorrelations between wind speed and both electron temperature and heat flux. These trends help us understand the mechanisms that shape the solar wind electron distributions at an early stage of their evolution.
WISPR Imaging of a Pristine CME
Authors: Hess Phillip , Rouillard Alexis P. , Kouloumvakos Athanasios , Liewer Paulett C. , Zhang Jie , Dhakal Suman , Stenborg Guillermo , Colaninno Robin C. , Howard Russell A.
Published: February 2020

The Wide-field Imager for Solar Probe (WISPR) on board the Parker Solar Probe (PSP) observed a coronal mass ejection (CME) on 2018 November 1, the first day of the initial PSP encounter. The speed of the CME, approximately 200–300 km s−1 in the WISPR field of view, is typical of slow, streamer blowout CMEs. This event was also observed by the Large Angle and Spectrometric Coronagraph Experiment (LASCO) coronagraphs. WISPR and LASCO view remarkably similar structures that enable useful cross-comparison between the two data sets as well as stereoscopic imaging of the CME. An analysis is extended to lower heights by linking the white-light observations to extreme ultraviolet (EUV) data from the Atmospheric Imaging Assembly, which reveal a structure that erupts more than a full day earlier before the CME finally gathers enough velocity to propagate outward. This EUV feature appears as a brightness enhancement in cooler temperatures, such as 171 Å, but as a cavity in nominal coronal temperatures, such as 193 Å. By comparing this circular, dark feature in 193 Å to the dark, white-light cavity at the center of the eruption in WISPR and LASCO, this is one coherent structure is seen to exist prior to the eruption in the low corona before entering the heliosphere and likely corresponds to the core of the magnetic flux rope. It is also believed that the relative weakness of the event contributed to the clarity of the flux rope in WISPR, as the CME did not experience impulsive forces or strong interaction with external structures that can lead to more complex structural evolution.
Identification of Magnetic Flux Ropes from Parker Solar Probe Observations during the First Encounter
Authors: Zhao L.-L. , Zank G. P. , Adhikari L. , Hu Q. , Kasper J. C. , Bale S. D. , Korreck K. E. , Case A. W. , Stevens M. , Bonnell J. W. , Dudok de Wit T. , Goetz K. , Harvey P. R. , MacDowall R. J. , Malaspina D. M. , Pulupa M. , Larson D. E. , Livi R. , Whittlesey P. , Klein K. G.
Published: February 2020

The Parker Solar Probe (PSP) observed an interplanetary coronal mass ejection (ICME) event during its first orbit around the Sun, among many other events. This event is analyzed by applying a wavelet analysis technique to obtain the reduced magnetic helicity, cross helicity, and residual energy, the first two of which are magnetohydrodynamics (MHD) invariants. Our results show that the ICME, as a large-scale magnetic flux rope, possesses high magnetic helicity, very low cross helicity, and highly negative residual energy, thus pointing to a magnetic fluctuation dominated structure. Using the same technique, we also search for small-scale coherent magnetic flux rope structures during the period from 2018 October 22 to November 21, which are intrinsic to quasi-two-dimensional MHD turbulence in the solar wind. Multiple structures with durations between 8 and 300 minutes are identified from PSP in situ spacecraft measurements. The location and scales of these structures are characterized by wavelet spectrograms of the normalized reduced magnetic helicity, normalized cross helicity, and normalized residual energy. Transport theory suggests that these small-scale magnetic flux ropes may contribute to the acceleration of charged particles through magnetic reconnection processes, and the dissipation of these structures may be important for understanding the coronal heating processes.
Turbulence Transport Modeling and First Orbit Parker Solar Probe (PSP) Observations
Authors: Adhikari L. , Zank G. P. , Zhao L.-L. , Kasper J. C. , Korreck K. E. , Stevens M. , Case A. W. , Whittlesey P. , Larson D. , Livi R. , Klein K. G.
Published: February 2020

The Parker Solar Probe (PSP) achieved its first orbit perihelion on 2018 November 6, reaching a heliocentric distance of about 0.165 au (35.55 R
⊙). Here, we study the evolution of fully developed turbulence associated with the slow solar wind along the PSP trajectory between 35.55 R
⊙ and 131.64 R
⊙ in the outbound direction, comparing observations to a theoretical turbulence transport model. Several turbulent quantities, such as the fluctuating kinetic energy and the corresponding correlation length, the variance of density fluctuations, and the solar wind proton temperature are determined from the PSP Solar Wind Electrons Alphas and Protons (SWEAP) plasma data along its trajectory between 35.55 R
⊙ and 131.64 R
⊙. The evolution of the PSP derived turbulent quantities are compared to the numerical solutions of the nearly incompressible magnetohydrodynamic (NI MHD) turbulence transport model recently developed by Zank et al. We find reasonable agreement between the theoretical and observed results. On the basis of these comparisons, we derive other theoretical turbulent quantities, such as the energy in forward and backward propagating modes, the total turbulent energy, the normalized residual energy and cross-helicity, the fluctuating magnetic energy, and the correlation lengths corresponding to forward and backward propagating modes, the residual energy, and the fluctuating magnetic energy.
The Solar Probe Cup on the Parker Solar Probe
Authors: Case A. W. , Kasper Justin C. , Stevens Michael L. , Korreck Kelly E. , Paulson Kristoff , Daigneau Peter , Caldwell Dave , Freeman Mark , Henry Thayne , Klingensmith Brianna , Bookbinder J. A. , Robinson Miles , Berg Peter , Tiu Chris , Wright K. H. , Reinhart Matthew J. , Curtis David , Ludlam Michael , Larson Davin , Whittlesey Phyllis , Livi Roberto , Klein Kristopher G. , Martinović Mihailo M.
Published: February 2020

Solar Probe Cup (SPC) is a Faraday cup instrument on board NASA’s Parker Solar Probe (PSP) spacecraft designed to make rapid measurements of thermal coronal and solar wind plasma. The spacecraft is in a heliocentric orbit that takes it closer to the Sun than any previous spacecraft, allowing measurements to be made where the coronal and solar wind plasma is being heated and accelerated. The SPC instrument was designed to be pointed directly at the Sun at all times, allowing the solar wind (which is flowing primarily radially away from the Sun) to be measured throughout the orbit. The instrument is capable of measuring solar wind ions with an energy between 100 and 6000 V (protons with speeds from 139 to 1072 km s−1). It also measures electrons with an energy/charge between 100 and 1500 V. SPC has been designed to have a wide dynamic range that is capable of measuring protons and alpha particles at the closest perihelion (9.86 solar radii from the center of the Sun) and out to 0.25 au. Initial observations from the first orbit of PSP indicate that the instrument is functioning well.
The Heliospheric Current Sheet in the Inner Heliosphere Observed by the Parker Solar Probe
Authors: Szabo Adam , Larson Davin , Whittlesey Phyllis , Stevens Michael L. , Lavraud Benoit , Phan Tai , Wallace Samantha , Jones-Mecholsky Shaela I. , Arge Charles N. , Badman Samuel T. , Odstrcil Dusan , Pogorelov Nikolai , Kim Tae , Riley Pete , Henney Carl J. , Bale Stuart D. , Bonnell John W. , Case Antony W. , Dudok de Wit Thierry , Goetz Keith , Harvey Peter , Kasper Justin C. , Korreck Kelly E. , Koval Andriy , Livi Roberto , MacDowall Robert J. , Malaspina David M. , Pulupa Marc
Published: February 2020

The Parker Solar Probe (PSP) completed its first solar encounter in 2018 November, bringing it closer to the Sun than any previous mission. This allowed in situ investigation of the heliospheric current sheet (HCS) inside the orbit of Venus. The Parker observations reveal a well defined magnetic sector structure placing the spacecraft in a negative polarity region for most of the encounter. The observed current sheet crossings are compared to the predictions of both potential field source surface and magnetohydrodynamic models. All the model predictions are in good qualitative agreement with the observed crossings of the HCS. The models also generally agree that the HCS was nearly parallel with the solar equator during the inbound leg of the encounter and more significantly inclined during the outbound portion. The current sheet crossings at PSP are also compared to similar measurements made by the Wind spacecraft near Earth at 1 au. After allowing for orbital geometry and propagation effects, a remarkable agreement has been found between the observations of these two spacecraft underlying the large-scale stability of the HCS. Finally, the detailed magnetic field and plasma structure of each crossing is analyzed. Marked differences were observed between PSP and Wind measurements in the type of structures found near the HCS. This suggests that significant evolution of these small solar wind structures takes place before they reach 1 au.
Observations of Energetic-particle Population Enhancements along Intermittent Structures near the Sun from the Parker Solar Probe
Authors: Bandyopadhyay Riddhi , Matthaeus W. H. , Parashar T. N. , Chhiber R. , Ruffolo D. , Goldstein M. L. , Maruca B. A. , Chasapis A. , Qudsi R. , McComas D. J. , Christian E. R. , Szalay J. R. , Joyce C. J. , Giacalone J. , Schwadron N. A. , Mitchell D. G. , Hill M. E. , Wiedenbeck M. E. , McNutt R. L. , Desai M. I. , Bale Stuart D. , Bonnell J. W. , de Wit Thierry Dudok , Goetz Keith , Harvey Peter R. , MacDowall Robert J. , Malaspina David M. , Pulupa Marc , Velli M. , Kasper J. C. , Korreck K. E. , Stevens M. , Case A. W. , Raouafi N.
Published: February 2020

Observations at 1 au have confirmed that enhancements in measured energetic-particle (EP) fluxes are statistically associated with “rough” magnetic fields, i.e., fields with atypically large spatial derivatives or increments, as measured by the Partial Variance of Increments (PVI) method. One way to interpret this observation is as an association of the EPs with trapping or channeling within magnetic flux tubes, possibly near their boundaries. However, it remains unclear whether this association is a transport or local effect; i.e., the particles might have been energized at a distant location, perhaps by shocks or reconnection, or they might experience local energization or re-acceleration. The Parker Solar Probe (PSP), even in its first two orbits, offers a unique opportunity to study this statistical correlation closer to the corona. As a first step, we analyze the separate correlation properties of the EPs measured by the Integrated Science Investigation of the Sun (IS⊙IS) instruments during the first solar encounter. The distribution of time intervals between a specific type of event, i.e., the waiting time, can indicate the nature of the underlying process. We find that the IS⊙IS observations show a power-law distribution of waiting times, indicating a correlated (non-Poisson) distribution. Analysis of low-energy (∼15 – 200 keV/nuc) IS⊙IS data suggests that the results are consistent with the 1 au studies, although we find hints of some unexpected behavior. A more complete understanding of these statistical distributions will provide valuable insights into the origin and propagation of solar EPs, a picture that should become clear with future PSP orbits.
Small, Low-energy, Dispersive Solar Energetic Particle Events Observed by Parker Solar Probe
Authors: Hill M. E. , Mitchell D. G. , Allen R. C. , de Nolfo G. A. , Vourlidas A. , Brown L. E. , Jones S. I. , McComas D. J. , McNutt R. L. , Mitchell J. G. , Szalay J. R. , Wallace S. , Arge C. N. , Christian E. R. , Cohen C. M. S. , Crew A. B. , Desai M. I. , Giacalone J. , Henney C. J. , Joyce C. J. , Krimigis S. M. , Leske R. A. , Mewaldt R. A. , Nelson K. S. , Roelof E. C. , Schwadron N. A. , Wiedenbeck M. E.
Published: February 2020

The Energetic Particle Instrument–Low Energy (EPI-Lo) experiment has detected several weak, low-energy (∼30–300 keV nucleon–1) solar energetic particle (SEP) events during its first two closest approaches to the Sun, providing a unique opportunity to explore the sources of low-energy particle acceleration. As part of the Parker Solar Probe (PSP) Integrated Science Investigation of the Sun (IS⊙IS) suite, EPI-Lo was designed to investigate the physics of energetic particles; however, in the special lowest-energy “time-of-flight only” product used in this study, it also responds to solar photons in a subset of approximately sunward-looking apertures lacking special light-attenuating foils. During the first three perihelia, in a frame rotating with the Sun, PSP undergoes retrograde motion, covering a 17° heliographic longitudinal range three times during the course of the ∼11-day perihelion passes, permitting a unique spatial and temporal study into the location, correlation, and persistence of previously unmeasurable SEPs. We examine the signatures of these SEPs (during the first PSP perihelion pass only) and the connection to possible solar sources using remote observations from the Solar Dynamics Observatory (SDO), the Solar TErrestrial RElations Observatory (STEREO), and the ground-based Global Oscillation Network Group (GONG). The orientation of the Sun relative to STEREO, SDO, and GONG makes such identifications challenging, but we do have several candidates, including an equatorial coronal hole at a Carrington longitude of ∼335°. To analyze observations from EPI-Lo, which is a new type of particle instrument, we examine instrumental effects and provide a preliminary separation of the ion signal from the photon background.
Measures of Scale-dependent Alfvénicity in the First PSP Solar Encounter
Authors: Parashar T. N. , Goldstein M. L. , Maruca B. A. , Matthaeus W. H. , Ruffolo D. , Bandyopadhyay R. , Chhiber R. , Chasapis A. , Qudsi R. , Vech D. , Roberts D. A. , Bale S. D. , Bonnell J. W. , de Wit T. Dudok , Goetz K. , Harvey P. R. , MacDowall R. J. , Malaspina D. , Pulupa M. , Kasper J. C. , Korreck K. E. , Case A. W. , Stevens M. , Whittlesey P. , Larson D. , Livi R. , Velli M. , Raouafi N.
Published: February 2020

The solar wind shows periods of highly Alfvénic activity, where velocity fluctuations and magnetic fluctuations are aligned or antialigned with each other. It is generally agreed that solar wind plasma velocity and magnetic field fluctuations observed by the Parker Solar Probe (PSP) during the first encounter are mostly highly Alfvénic. However, quantitative measures of Alfvénicity are needed to understand how the characterization of these fluctuations compares with standard measures from prior missions in the inner and outer heliosphere, in fast wind and slow wind, and at high and low latitudes. To investigate this issue, we employ several measures to quantify the extent of Alfvénicity—the Alfvén ratio r
A, the normalized cross helicity σ

c
, the normalized residual energy σ

r
, and the cosine of angle between velocity and magnetic fluctuations

. We show that despite the overall impression that the Alfvénicity is large in the solar wind sampled by PSP during the first encounter, during some intervals the cross helicity starts decreasing at very large scales. These length scales (often >1000d

i
) are well inside inertial range, and therefore, the suppression of cross helicity at these scales cannot be attributed to kinetic physics. This drop at large scales could potentially be explained by large scale shears present in the inner heliosphere sampled by PSP. In some cases, despite the cross helicity being constant down to the noise floor, the residual energy decreases with scale in the inertial range. These results suggest that it is important to consider all these measures to quantify Alfvénicity.
Density Fluctuations in the Solar Wind Based on Type III Radio Bursts Observed by Parker Solar Probe
Authors: Krupar Vratislav , Szabo Adam , Maksimovic Milan , Kruparova Oksana , Kontar Eduard P. , Balmaceda Laura A. , Bonnin Xavier , Bale Stuart D. , Pulupa Marc , Malaspina David M. , Bonnell John W. , Harvey Peter R. , Goetz Keith , Dudok de Wit Thierry , MacDowall Robert J. , Kasper Justin C. , Case Anthony W. , Korreck Kelly E. , Larson Davin E. , Livi Roberto , Stevens Michael L. , Whittlesey Phyllis L. , Hegedus Alexander M.
Published: February 2020

Radio waves are strongly scattered in the solar wind, so that their apparent sources seem to be considerably larger and shifted than the actual ones. Since the scattering depends on the spectrum of density turbulence, a better understanding of the radio wave propagation provides indirect information on the relative density fluctuations,

, at the effective turbulence scale length. Here, we analyzed 30 type III bursts detected by Parker Solar Probe (PSP). For the first time, we retrieved type III burst decay times,

, between 1 and 10 MHz thanks to an unparalleled temporal resolution of PSP. We observed a significant deviation in a power-law slope for frequencies above 1 MHz when compared to previous measurements below 1 MHz by the twin-spacecraft Solar TErrestrial RElations Observatory (STEREO) mission. We note that altitudes of radio bursts generated at 1 MHz roughly coincide with an expected location of the Alfvén point, where the solar wind becomes super-Alfvénic. By comparing PSP observations and Monte Carlo simulations, we predict relative density fluctuations, ϵ, at the effective turbulence scale length at radial distances between 2.5 and 14 

to range from 0.22 to 0.09. Finally, we calculated relative density fluctuations, ϵ, measured in situ by PSP at a radial distance from the Sun of 35.7 

during perihelion #1, and perihelion #2 to be 0.07 and 0.06, respectively. It is in a very good agreement with previous STEREO predictions (

) obtained by remote measurements of radio sources generated at this radial distance.
Carbon Chain Depletion of 2I/Borisov
Authors: Kareta Theodore , Andrews Jennifer , Noonan John W. , Harris Walter M. , Smith Nathan , O’Brien Patrick , Sharkey Benjamin N. L. , Reddy Vishnu , Springmann Alessondra , Lejoly Cassandra , Volk Kathryn , Conrad Albert , Veillet Christian
Published: February 2020

The composition of comets in the solar system comes in multiple groups thought to encode information about their formation in different regions of the outer protosolar disk. The recent discovery of the second interstellar object, 2I/Borisov, allows for spectroscopic investigations into its gas content and a preliminary classification of it within the solar system comet taxonomies to test the applicability of planetesimal formation models to other stellar systems. We present spectroscopic and imaging observations from 2019 September 20 through October 26 from the Bok, MMT telescope (formerly the Multiple Mirror Telescope, Mount Hopkins, Arizona), and Large Binocular Telescopes. We identify CN in the comet’s spectrum and set precise upper limits on the abundance of C2 on all dates in October. We use a Haser model to convert our integrated fluxes to production rates and find Q(CN) = (1.1–1.9) ∗ 1024 mols s−1 increasing over 2019 October 1 to 26, consistent with contemporaneous observations. We set our lowest upper limit on a C2 production rate, Q(C2) < 1.6 ∗ 1023 mols s−1 on 2019 October 10. The measured upper limit ratio for that date Q(C2)/Q(CN) < 0.1 indicates that 2I/Borisov is strongly in the (carbon-chain) “depleted” taxonomic group if there is any C2 production at all. Most “depleted” comets are Jupiter-family comets (JFCs), perhaps indicating a similarity in formation conditions between the most depleted of the JFCs and 2I/Borisov. More work is needed to understand the applicability of our knowledge of solar system comet taxonomies onto interstellar objects and we discuss future work that could help to clarify the usefulness of the approach.
Heterogeneity and Persistence in Returns to Wealth
Authors: Fagereng Andreas , Guiso Luigi , Malacrino Davide , Pistaferri Luigi
Published: February 2020

We provide a systematic analysis of the properties of individual returns to wealth using 12 years of population data from Norway's administrative tax records. We document a number of novel results. First, individuals earn markedly different average returns on their net worth (a standard deviation of 22.1%) and on its components. Second, heterogeneity in returns does not arise merely from differences in the allocation of wealth between safe and risky assets: returns are heterogeneous even within narrow asset classes. Third, returns are positively correlated with wealth: moving from the 10th to the 90th percentile of the net worth distribution increases the return by 18 percentage points (and 10 percentage points if looking at net‐of‐tax returns). Fourth, individual wealth returns exhibit substantial persistence over time. We argue that while this persistence partly arises from stable differences in risk exposure and assets scale, it also reflects heterogeneity in sophistication and financial information, as well as entrepreneurial talent. Finally, wealth returns are correlated across generations. We discuss the implications of these findings for several strands of the wealth inequality debate.
Endogenous Production Networks
Authors: Acemoglu Daron , Azar Pablo D.
Published: February 2020

We develop a tractable model of endogenous production networks. Each one of a number of products can be produced by combining labor and an endogenous subset of the other products as inputs. Different combinations of inputs generate (prespecified) levels of productivity and various distortions may affect costs and prices. We establish the existence and uniqueness of an equilibrium and provide comparative static results on how prices and endogenous technology/input choices (and thus the production network) respond to changes in parameters. These results show that improvements in technology (or reductions in distortions) spread throughout the economy via input–output linkages and reduce all prices, and under reasonable restrictions on the menu of production technologies, also lead to a denser production network. Using a dynamic version of the model, we establish that the endogenous evolution of the production network could be a powerful force towards sustained economic growth. At the root of this result is the fact that the arrival of a few new products expands the set of technological possibilities of all existing industries by a large amount—that is, if there are
n products, the arrival of one more new product increases the combinations of inputs that each existing product can use from 2

n−1
to 2

n
, thus enabling significantly more pronounced cost reductions from choice of input combinations. These cost reductions then spread to other industries via lower input prices and incentivize them to also adopt additional inputs.
Discriminatory price auctions with resale and optimal quantity caps
Authors: Baisa Brian , Burkett Justin
Published: February 2020

We present a model of a discriminatory price auction in which a large bidder competes against many small bidders, followed by a post‐auction resale stage in which the large bidder is endogenously determined to be a buyer or a seller. We extend results on first‐price auctions with resale to this setting and use these results to give a tractable characterization of equilibrium behavior. We use this characterization to study the policy of capping the amount that may be won by large bidders in the auction, a policy that has received little attention in the auction literature. Our analysis shows that the trade‐offs involved when adjusting these quantity caps can be understood in terms familiar to students of asymmetric first‐price single‐unit auctions. Furthermore, whether one seeks to maximize welfare or revenue can have contradictory implications for the choice of cap.