3,110 research outputs found
Formation of Atomic Carbon Chains from Graphene Nanoribbons
The formation of one-dimensional carbon chains from graphene nanoribbons is
investigated using it ab initio molecular dynamics. We show under what
conditions it is possible to obtain a linear atomic chain via pulling of the
graphene nanoribbons. The presence of dimers composed of two-coordinated carbon
atoms at the edge of the ribbons is necessary for the formation of the linear
chains, otherwise there is simply the full rupture of the structure. The
presence of Stone-Wales defects close to these dimers may lead to the formation
of longer chains. The local atomic configuration of the suspended atoms
indicates the formation of single and triple bonds, which is a characteristic
of polyynes.Comment: 4 pages, 5 figure
Acessos de mandioca açucarada coletados no Nordeste paraense possuem o mesmo genótipo detectado por marcadores microssatélites.
A mandioca é encontrada na região Norte do Brasil e é usada como fonte de subsistência para muitas famílias. A mandioca açucarada ou mandiocaba, é um tipo de mandioca que armazena em suas raízes, além do amido, açúcares livres como reservas. Atualmente, vêm recebendo destaque pelo seu potencial para uso na fabricação de álcool combustível, devido ao acúmulo de glicose que pode ser convertida em etanol diretamente. Foi realizado teste para avaliar a diversidade genética de acessos de mandiocas açucaradas coletadas em diferentes locais do estado do Pará mantidos no banco de germoplasma da Embrapa Amazônia Oriental. Foi realizada a genotipagem molecular de nove acessos de mandioca açucarada e um acesso de mandioca brava com marcadores microssatélites. Para isso, foram utilizados 13 primers microssatélites e a corrida dos produtos amplificados foi realizada em géis de poliacrilamida 6%. Após a análise dos géis, foi verificado que todas as nove amostras de mandioca açucarada possuíam o mesmo genótipo, sendo verificada baixa variabilidade genética para esse grupo de mandiocas
Assessment of the Italian version of the Internet Disorder Scale (IDS-15)
Much research has focused on the validation of psychometric tools assessing Internet addiction. One of the newest measures is the Internet Disorder Scale (IDS-15) based on the modified IGD criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). This study aimed at investigating the psychometric properties of the Italian version of the IDS-15 by examining the construct and the concurrent and the criterion-related validity and by identifying the taxonomy and the patterns of Internet users. A sample of 471 participants (Mage = 24.72 years, SD = 8.66; 256 males) was recruited from secondary schools, universities, and gaming halls. Confirmatory factor analyses supported the four-dimensional second-order structure and the three levels of the measurement invariance across gender. The reliability and the validity of the scale were confirmed, and the LPAs provided four classes of Internet users on the basis of the scores obtained in all four dimensions of the scale. The psychometric robustness of the Italian version of the IDS-15 was clearly demonstrated. Cross-cultural research should expand and generalize the present findings
Item response theory analysis of the recoded Internet Gaming Disorder Scale-Short-Form (IGDS9-SF)
Based on the nine criteria for Internet gaming disorder (IGD) in DSM-5, the Internet Gaming Disorder Scale 9-Short Form (IGDS9-SF; Pontes and Griffiths 2015) is the most widely used questionnaire for assessing IGD. The present study examined support for the unidimensional factor structure of the instrument, with a group of 868 adolescent and adult gamers from the USA, with criteria recoded as present or absent. The two-parameter logistic model (2PLM) was used to examine the item response theory properties of the criteria included in the measure. Confirmatory factor analysis supported the one-factor model. The 2PLM analysis indicated that all the criteria were strong discriminators of high and low latent IGD. Furthermore, the items measured more of the GAD dimension and with more precision from around +2 SD from the mean trait level. The implications of the findings for interpreting the IGDS9-SF scores for clinical practice are discussed
3 axis polymeric accelerometer and method of production
The present invention consists in a thermal accelerometer capable of detecting
acceleration in multiple axes. The accelerometer is made of four microinjected
polymeric parts (1, 2, 3, 4), which can be two identical top parts and two identical
central parts or four different parts, which are assembled with active polymeric
membranes (5, 6, 7) to construct the 3-axis acceleration sensing device. The
microinjected parts provide mechanical support for the heater and temperature
sensors that are placed on the membranes. The device operating gas medium is
hermetically sealed by the polymer parts and electrical current applied to the
heater causes the air to heat and external acceleration imposes a gradient of
temperature sensed by the thermal sensing elements
Procedimento de operação, manutenção e verificação de centrífuga JOUAN refrigerada.
bitstream/CENARGEN/29585/1/ct064.pd
Orbital Exenteration for Eyelid Skin Carcinoma
Exenteration of the orbit is a disfiguring and destructive procedure; it is generally performed for orbital malignancies and often provides a significant reconstructive
challenge. Our purpose was to evaluate the clinical indications for orbital exenteration in a tertiary referral
center and to assess the reconstructive options employed. A retrospective nonrandomized analysis was performed,
selecting all patients undergoing orbital exenteration over a 5-year period, between January 2005 and January 2010.
Patient demographics, tumor characteristics, and reconstructive techniques used were evaluated. Twenty patients with a mean age of 76.5 years underwent total orbital
exenteration. Basal cell carcinoma was the main operative indication (45%), followed by squamous cell carcinoma (15%). Reconstructive techniques included cover of the raw orbital cavity with a temporal muscular flap in all cases followed with split skin grafting (25%), bilaterally pedicle V-Y advancement flap (10%) and a fasciocutaneous island flap of the retroauricular region (65%). Twenty percent of patients had local complications and all were treated in a satisfactory fashion. Eyelid skin tumors remain an important
cause of orbital exenteration. Temporal muscle flap is a reliable and stable reconstructive solution after orbital
exenteration and additional aid is supplied with skin grafts or local flaps. This technique ensures a good aesthetic
outcome and better situation for later complementary treatments and minimal associated donor site morbidity
Análise genética entre acessos de Oenocarpus mapora (Arecaceae) de hábito cespitoso e solitário.
A bacaby ou Oenocarpus mapora é uma palmeira considerada potencial para a domesticação devido às suas características comerciais de seu fruto e palmito. A espécie tem hábito predominantemente cespitoso, mas palmeiras de hábito solitário já foram descritas. O banco de germoplasma (BAG) do complexo Oenocarpus/Jessenia da Embrapa Amazônia Oriental possui em seu acervo uma amostra de materiais do tipo solitário de O. mapora coletados no noroeste paraense. Para veriicar a diversidade genética desse grupo no BAG e sua proximidade genética com materiais de hábito cespitoso, foram utilizados 18 indivíduos do tipo solitário para serem comparados com 1γ indivíduos do tipo cespitoso coletados em Itacoatiara (Aε) e oito coletados em Parintins (Aε), por meio de genotipagem com cinco locos microssatélites. A análise descritiva mostrou que há variabilidade genética dentro do grupo do tipo solitário, com H E = 0,7λ, variação que foi maior que a dos grupos de hábito cespitoso. A análise com AεOVA demonstrou grande diferenciação entre os grupos, com γβ,γη% de variação genética entre grupos. A distância genética par a par com base em FST mostrou que houve diferença significativa entre os grupos, e que o grupo do tipo solitário teve mais proximidade genética com um dos grupos do tipo cespitoso, do que entre os grupos do tipo cespitoso, indicando que o material pode ser utilizado em programas de melhoramento
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