1,721,765 research outputs found
Symbiotic specificity and nodulation in the southern African legume clade Lotononis s. l. and description of novel rhizobial species within the Alphaproteobacterial genus Microvirga
Full text linkLotononis s. l. is a legume clade within the Crotalarieae tribe, with a centre of origin in South Africa. After taxonomic revision, the three genera Listia, Leobordea and Lotononis s. str. are now recognised. The N2-fixing symbiosis between Listia bainesii and pigmented Methylobacterium rhizobia is known to be highly specific, while a recent study has shown that Listia angolensis is effectively nodulated by a novel lineage of root nodule bacteria. The symbiotic relationships of Lotononis s. l. species outside the Listia genus have not yet been examined. The work presented in this thesis sought to determine the identity of rhizobia isolated from Listia, Leobordea and Lotononis s. str. hosts, to examine the phylogeny of their nodA genes and to quantify the nodulation and N2 fixation capabilities of Lotononis s. l.- associated rhizobia on eight taxonomically diverse Lotononis s. l. hosts. Additionally, this research sought to examine the processes of infection and nodule initiation in L. angolensis and L. bainesii and to validly name and characterise the novel L. angolensis rhizobia.
Amplification and sequencing of nearly full length fragments of the 16S rRNA gene showed that the rhizobia isolated from nodules of Lotononis s. l. species were phylogenetically diverse. Strains isolated from Leobordea and Lotononis s. str. hosts were most closely related to Bradyrhizobium spp., Ensifer meliloti, Mesorhizobium tianshanense and Methylobacterium nodulans. The Listia angolensis microsymbionts, together with closely related Lupinus texensis rhizobia, were identified as novel species of the Alphaproteobacterial genus Microvirga. The xiii phylogeny of the nodA genes correlated more with the rhizobial 16S rRNA genes than with the taxonomy of the host plants.
The nodulation and effectiveness trials confirmed the symbiotic specificity of the genus Listia. L. bainesii nodulated only with the representative pigmented Methylobacterium strain WSM2598. As measured by plant shoot dry weight, this symbiosis was highly effective. L. angolensis was effectively nodulated only by Microvirga rhizobia, but formed ineffective nodules with the pigmented Methylobacterium and M. nodulans strains. WSM2598 was effective only on Listia species (other than L. angolensis). In contrast, the Microvirga strain WSM3557 was partially effective on some Leobordea and Lotononis s. str. species. No clear pattern of symbiotic association was seen in the Leobordea and Lotononis s. str. hosts. Nodulation in these species was usually promiscuous and often ineffective for N2 fixation.
The nodules formed on Listia species were lupinoid, whereas the nodules of Leobordea and Lotononis s. str. species were indeterminate. Micrographs of all sectioned nodules, whether lupinoid or indeterminate, showed a mass of central, uniformly infected tissue, with no uninfected interstitial cells. Rhizobial infection and nodulation in L. angolensis and L. bainesii did not appear to involve root hair curling or the development of infection threads. Nodule organogenesis followed a process similar to that observed in Lupinus species, with nodule primordia developing in the outer cortex.
The polyphasic characterisation of the Microvirga rhizobia associated with Listia angolensis and Lupinus texensis resulted in the description of three new rhizobial species: Microvirga lotononidis, M. zambiensis and M. lupini. Microvirga species possess several phenotypic properties that are unusual in rhizobia, including the ability to grow at relatively elevated temperatures and the presence of pigmentation in most strains. The rhizobial Microvirga strains WSM3557T and Lut6T have been included in the Genomic Encyclopedia for Bacteria and Archaea Root Nodule Bacteria (GEBA-RNB) sequencing project (Kyrpides & Reeve, collaborative CSI project (http://genome.jgi-psf.org/programs/bacteria-archaea/GEBA-RNB.jsf) and should provide new insights into the evolution of and genomic architecture required for rhizobial symbionts
Nodule morphology, symbiotic specificity and association with unusual rhizobia are distinguishing features of the genus Listia within the southern African crotalarioid clade Lotononis s.l.
No full textBackground and Aims: The legume clade Lotononis sensu lato (s.l.; tribe Crotalarieae) comprises three genera: Listia, Leobordea and Lotononis sensu stricto (s.s.). Listia species are symbiotically specific and form lupinoid nodules with rhizobial species of Methylobacterium and Microvirga. This work investigated whether these symbiotic traits were confined to Listia by determining the ability of rhizobial strains isolated from species of Lotononis s.l. to nodulate Listia, Leobordea and Lotononis s.s. hosts and by examining the morphology and structure of the resulting nodules.
Methods: Rhizobia were characterized by sequencing their 16S rRNA and nodA genes. Nodulation and N2 fixation on eight taxonomically diverse Lotononis s.l. species were determined in glasshouse trials. Nodules of all hosts, and the process of infection and nodule initiation in Listia angolensis and Listia bainesii, were examined by light microscopy.
Key Results: Rhizobia associated with Lotononis s.l. were phylogenetically diverse. Leobordea and Lotononis s.s. isolates were most closely related to Bradyrhizobium spp., Ensifer meliloti, Mesorhizobium tianshanense and Methylobacterium nodulans. Listia angolensis formed effective nodules only with species of Microvirga. Listia bainesii nodulated only with pigmented Methylobacterium. Five lineages of nodA were found. Listia angolensis and L. bainesii formed lupinoid nodules, whereas nodules of Leobordea and Lotononis s.s. species were indeterminate. All effective nodules contained uniformly infected central tissue. Listia angolensis and L. bainesii nodule initials occurred on the border of the hypocotyl and along the tap root, and nodule primordia developed in the outer cortical layer. Neither root hair curling nor infection threads were seen.
Conclusions: Two specificity groups occur within Lotononis s.l.: Listia species are symbiotically specific, while species of Leobordea and Lotononis s.s. are generally promiscuous and interact with rhizobia of diverse chromosomal and symbiotic lineages. The seasonally waterlogged habitat of Listia species may favour the development of symbiotic specificity
Tiffani Listia D's Quick Files
No full textThe Quick Files feature was discontinued and it’s files were migrated into this Project on March 11, 2022. The file URL’s will still resolve properly, and the Quick Files logs are available in the Project’s Recent Activity
Tiffani Listia D's Quick Files
No full textThe Quick Files feature was discontinued and it’s files were migrated into this Project on March 11, 2022. The file URL’s will still resolve properly, and the Quick Files logs are available in the Project’s Recent Activity
Studi emisi tungku masak rumah tangga [Skripsi] / Lia Listia Sari
No full textBibl. : 446-48x, 48 hlm. : ill. 28 cm. . -- Lamp. ( 28 lemba
ANALISIS KESALAHAN SISWA DALAM MENYELESAIKAN SOAL CERITA PADA MATERI TEOREMA PYTHAGORAS
Full text linkABSTRAK
Listia Novitasari (1801079). Analisis Kesalahan Siswa dalam Menyelesaikan Soal Cerita pada Materi Teorema Pythagoras.
Penelitian ini bertujuan untuk mendeskripsikan kesalahan siswa dalam menyelesaikan soal cerita materi Teorema Pythagoras, faktor penyebab dan solusinya. Penelitian ini menggunakan pendekatan kualitatif, dengan desain yang digunakan ialah studi kasus. Subjek penelitian ini adalah siswa kelas VIII dan IX dari salah satu sekolah di kota Subang. Pengumpulan data dilakukan dengan menggunakan instrumen tes berupa soal cerita pada materi Teorema Pythagoras, wawancara dengan siswa dan guru, serta studi dokumentasi. Berdasarkan hasil penelitian, ditemukan semua jenis kesalahan menurut Newman yaitu kesalahan membaca, kesalahan memahami, kesalahan transformasi, kesalahan keterampilan proses dan kesalahan penulisan jawaban. Kesalahan yang paling banyak ditemukan ada kesalahan keterampilan proses. Hal ini disebabkan oleh beberapa faktor diantaranya: 1) siswa tidak menyukai soal berbentuk cerita, 2) siswa kurang teliti dan tidak memahami soal, 3) siswa keliru dalam memodelkan rumus dan siswa kurang paham dalam mengerjakan soal, 4) siswa tidak teliti dan kurang menguasai proses perhitungan, 5) siswa tidak memeriksa kembali hasil jawaban yang telah diperoleh. Adapun salah satu solusi untuk mengatasinya yaitu siswa diberikan penguatan kembali terkait materi Teorema Pythagoras dan siswa harus dibiasakan dengan latihan soal - soal yang berbasis pemecahan masalah serta diarahkan bagaimana siswa harus menjawab soal tersebut.
Kata Kunci: Analisis Kesalahan Siswa, Soal Teorema Pythagoras
ABSTRACT
Listia Novitasari (1801079). Analysis of Student Errors in Solving Story Problems on Pythagorean Theorem Material.
This study describes students' mistakes in solving the Pythagorean Theorem material story problems, the causes, and solutions. This study uses a qualitative approach, with the design used being a case study. The subjects of this study were students of classes VIII and IX from a school in the city of Subang. Data was collected using test instruments in the form of story questions on the Pythagorean Theorem material, interviews with students and teachers, and documentation studies. Based on the results of the study, Newman found all types of errors, reading errors, comprehension errors, transformation errors, process skills errors and encoding errors. The most common errors found were process skills errors. This is caused by several factors including: 1) the students do not like story-shaped questions, 2) the students are not be careful and do not understand of questions, 3) the students are wrong in modeling formulas and students not understand how to do on questions, 4) the students are not carrectly and lack mastery calculation process, 5) the students do not re-check the results of the answers that have been obtained. One solution to overcome this is that students are given reinforcement related to the Pythagorean Theorem material and students must be familiarized with practice questions based on problem solving and directed how students should answer these questions.
Keywords: Student Error Analysis, Pythagorean Theorem Problem
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The Sustainability of Traditional Packaging of Snacks and Beverages Against Modernity
Full text linkIn this global era, we notice that the modern material begins to replace traditional packaging of snacks and beverages with natural material. This study wants to examine the condition of traditional packaging of snacks and beverages and how modernity influencing decision to use the existing packaging. This study focus on traditional packaging of snacks and beverages that exist in the northern coast of East Java, especially Gresik, Lamongan and Tuban. This is a qualitative descriptive research using survey, observation and deep interviews as its method. We classify the various functions of natural materials for snacks and beverages packaging namely as primary, alternative and additional packaging. Producers use packaging made from natural material as a function that cannot be replaced by modern packaging, such as material affect typical aroma of the product, provide a flavor according to the materials used, give specific traditional characteristic which being attached to products and make the product more durable. Along with the development of more modern era, natural materials getting more difficult to obtain because there is no more land to plant these materials, it makes the material price more expensive. Besides, modern practical packaging offers packaging with a more convenience and neat appearance. But it turns out that there are a variety of factors besides economic, such as social, cultural, and political that make producers keep using natural materials and maintain traditional appearances in their products
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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