1,010 research outputs found

    Magnetic helicity and energy budget around large confined and eruptive solar flares

    Full text link
    We investigate the coronal magnetic energy and helicity budgets of ten solar ARs, around the times of large flares. In particular, we are interested in a possible relation of the derived quantities to the particular type of the flares that the AR produces, i.e., whether they are associated with a CME or they are confined. Using an optimization approach, we employ time series of 3D nonlinear force-free magnetic field models of ten ARs, covering a time span of several hours around the time of occurrence of large solar flares (GOES class M1.0 and larger). We subsequently compute the 3D magnetic vector potentials associated to the model 3D coronal magnetic field using a finite-volume method. This allows us to correspondingly compute the coronal magnetic energy and helicity budgets, as well as related (intensive) quantities such as the relative contribution of free magnetic energy, EF/EE_{\mathrm{F}}/{E} (energy ratio), the fraction of non-potential (current-carrying) helicity, HJ/HV|H_{\mathrm{J}}|/|{H_{V}}| (helicity ratio), and the normalized current-carrying helicity, HJ/ϕ2|H_{\mathrm{J}}|/{\phi^{\prime}}^{2}. The total energy and helicity budgets of flare-productive ARs (extensive parameters) cover a broad range of magnitudes, with no obvious relation to the eruptive potential of the individual ARs, i.e., whether or not a CME is produced in association with the flare. The intensive eruptivity proxies, EF/EE_{\mathrm{F}}/{E} and HJ/HV|H_{\mathrm{J}}|/|{H_{V}}|, and HJ/ϕ2|H_{\mathrm{J}}|/{\phi^{\prime}}^{2}, however, seem to be distinctly different for ARs that produced CME-associated large flares compared to those which produced confined flares. For the majority of ARs in our sample, we are able to identify characteristic pre-flare magnitudes of the intensive quantities, clearly associated to subsequent CME-productivity.Comment: Accepted for publication in A & A journal, 19 pages, and 11 figure

    Seagrass Community at Kampung Ambong\u27s Water East Likupang Subdistrict, North Minahasa Regency

    Full text link
    Penelitian ini dilakukan di Perairan Kampung Ambong Kecamatan Likupang Timur Kabupaten Minahasa Utara.Tujuan dari penelitian ini mengetahui komposisi jenis lamun dan menganalisis kepadatan, indeks dominasi, indeks keanekaragaman, indeks kemerataan. Pengambilan data dilakukan dengan metode garis transek. Penempatan transek di bagi menjadi 3 garis transek yang di letakkan tegak lurus garis pantai dengan panjang masing-masing garis transek 95 meter. Sedangkan jarak antara transek 1 dengan transek yang lain (2 dan 3) masing-masing 100 m. Dari hasil penelitian komposisi jumlah spesies lamun (seagrass) adalah 10. Kesepuluh spesies yang teridentifikasi yaitu: Cymodocea rotundata, Syringodium isoetifolium, Halophila decipiens, Halodule pinifolia, Cymodocea serrulata, Enhalus acoroides, Halphila minor, Thalassia hempricii, Halodule uninervis, Halophila spinulosa.Kepadatan masing-masing spesies diperoleh menunjukkan nilai tertinggi yaitu Cymodocea rotundata 2608 individu/m2, Syringodium isoetifolium 816 individu/m2, Halophila decipiens 420 individu/m2, Halodule pinifolia 292 individu/m2, Cymodocea serrulata 268 individu/m2, Enhalus acoroides 260 individu/m2, Halophila minor 224 individu/m2, Thalassia hempricii 160individu/m2, Halodule uninervis 124individu/m2, Halophila spinulosa 20 individu/m2. Sedangkan indeks dominasi diperoleh 0.3 berada dalam kategori rendah, artinya tidak ada spesies yang mendominasi di perairan tersebut. Indeks keanekaragaman diperoleh 1.65 berada dalam kategori sedang. Hal ini menunjukkan bahwa komunitas spesies dalam kondisihampir merata, karena memiliki peluang yang sama. Indeks kemerataan diperoleh 0.72 berada dalam kategori tinggi, karena memiliki padang lamun campuran

    SU(N) Coherent States and Irreducible Schwinger Bosons

    Full text link
    We exploit the SU(N) irreducible Schwinger boson to construct SU(N) coherent states. This construction of SU(N) coherent state is analogous to the construction of the simplest Heisenberg-Weyl coherent states. The coherent states belonging to irreducible representations of SU(N) are labeled by the eigenvalues of the (N1)(N-1) SU(N) Casimir operators and are characterized by (N1)(N-1) complex orthonormal vectors describing the SU(N) group manifold.Comment: 12 pages, 3 figure

    Groundwater Exploration using 1D and 2D Electrical Resistivity Methods

    Get PDF
    Integrated geophysical techniques involving 2D electrical resistivity imaging (ERI) and vertical electrical sounding (VES) were used to delineate groundwater potential zones for borehole siting in the Pru District of the Brong Ahafo Region of Ghana. The ABEM Terrameter LS was employed in the survey. A total of fifteen (15) 400 m - ERT profiles and thirty-one (31) VES points were investigated using the Schlumberger protocol. The Res1DINV and Res2DINV inversion software were used for data analysis. The 2D ERI images showed a lot of fractures within the subsurface of the study area. The results of the VES generally revealed either three or four subsurface geological layers at the selected points. The second and third layers were found to possess relatively low-to-moderate resistivity values indicative of potential aquifer zones. The resistivity of the fourth layer indicated the presence of slightly-fractured to fresh bedrock. The borehole logs depict four sequences: brownish or lateritic sandy clay overlying highly weathered sandstone which is underlain by moderately weathered sandstone and highly fractured sandstone basement. Keywords: Electrical resistivity tomography, vertical electrical sounding, groundwater, aquifer, geological layer and hydrogeology

    Coherent States with SU(N) Charges

    Full text link
    We define coherent states carrying SU(N) charges by exploiting generalized Schwinger boson representation of SU(N) Lie algebra. These coherent states are defined on 2(2N11)2 (2^{N - 1} - 1) complex planes. They satisfy continuity property and provide resolution of identity. We also exploit this technique to construct the corresponding non-linear SU(N) coherent states.Comment: 18 pages, LaTex, no figure

    Yam Tuber Dormancy and Sprouting: The Role of Concentration Dynamics of Endogenous Gibberellic Acid

    Get PDF
    The role of endogenous gibberellic acid (GA ) in the regulation of yam (Dioscorea spp.) tuber 3 dormancy was investigated by determining the changes in the endogenous GA levels during 3 natural dormancy progression. Two Dioscorea rotundata cultivars ('Pona' and 'Labreko') and one Dioscorea alata cultivar ('CRI-Ahoɔdenfoɔ') used in these studies have varying dormancy duration. Endogenous GA levels determined for the yam tubers ranged from 1.53 – 3.05 mg/g dw 3 and 1.23 – 1.58 mg/g dw for 'Pona'; 1.53 – 3.40 mg/g dw and 1.25–1.57 mg/g dw for 'Labreko'; 1.48 – 3.62 mg/g dw and 1.28 – 1.60 mg/g dw for 'CRI-Ahoɔdenfoɔ', respectively, for the outer and inner portions. 'Pona' and 'Labreko' had dormancy break at 60 days after harvest (DAH), but at 90 DAH for 'CRI-Ahoɔdenfoɔ'. Generally, GA levels increased from harvest to the maximum 3 at 30 DAH, then declined to the minimum at 60 DAH before finally increasing again at 90 DAH for the outer portions of the yam tuber. For the inner portions of the tuber, GA levels rather 3 declined significantly to the minimum at 30 DAH, increased at 60 DAH and then decreased again at 90 DAH. GA levels in the outer portions of the tubers increased by 84-122%, 65-77% and 61- 3 65%, respectively, in 'CRI-Ahoɔdenfoɔ', 'Labreko' and 'Pona', but decreased in the inner portions by 19-23%, 24-26% and 26-28%. Essentially, higher amounts of endogenous gibberellins in yam tubers induced longer dormancy duration whereas lower amounts were indicative of dormancy termination and subsequent initiation of sprouting.&nbsp

    Exploration of the nurse shark (Ginglymostoma cirratum) plasma immunoproteome using high-resolution LC-MS/MS

    Get PDF
    Funding Information: FKB was supported by a BBSRC-funded EASTBIO Doctoral Training Partnership studentship (grant number BB/M010996/1) awarded to HD. HM is supported by NIH-NIAID predoctoral fellowship F31AI147532. DM received institutional strategic funding from the BBSRC (grants: BBS/E/D/10002071 and BBS/E/D/20002174). For the purpose of open access, the author has applied a Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising from this submission. Funding Information: We thank Professor Sam Martin (University of Aberdeen) for supporting the supervision of FKB during her PhD. Our thanks also to Luke Tallon and Lisa Sadzewicz at UMBs Institute for Genome Sciences for helpful advice and sharing their expertise during sequencing of the nurse shark transcriptome. Publisher Copyright: Copyright © 2022 Bakke, Gundappa, Matz, Stead, Macqueen and Dooley.Peer reviewedPublisher PD

    Konsep dan Metode Desain Arsitektur Bernard Tschumi

    Get PDF
    Born in Lausanne, Bernard Tschumi (1944) can be considered one of the main interpreters of deconstructionism. Early in his career, Tschumi focused on criticism and problems in architecture with a multidisciplinary approach (borrowing from music and film). This study aims to obtain Bernard Tschumi's architectural design concepts and methods that are useful for precedents for architectural education and professional activities. This research refers to the view that architectural objects can have the same value as objects that result from a repetitive activity. And even deliberately made so that it can be repeated forever. That is, an architectural object not only produces a repetition, but also results from a repetition. This research uses content analysis method by studying the conceptual thinking and design methods of architect Bernard Tschumi through literature are divided into: Group I, in the form of theoretical works from Bernard Tschumi and Group II, in the form of architectural works. The results of the study found that Bernard Tschumi revealed that architecture is about disjunctive of spaces, events and movements. This opinion is then raised in several main concepts that can be grouped into: 1) Space & events, 2) Plan, juxtaposition, overlay, 3) Vectors & Envelopes, 4) Concept, context, content, 5) Form - Concept. And to apply theory and concepts into design, Tschumi uses several methods, namely: 1) Cross Programming; 2) Transprogramming; 3) Dispogramming; 4) Transformation; 5) Superimposition; 6) Combination; 7) Disjunction; 8) Cinegram-montage.Dilahirkan di Lausanne, Bernard Tschumi (1944) dapat dianggap sebagai salah satu penafsir utama dekonstruksionisme. Pada awal karirnya, Tschumi berfokus pada kritik dan masalah dalam arsitektur dengan pendekatan multidisiplin (meminjam dari musik dan film). Penelitian ini betujuan untuk mendapatkan konsep dan metode desain arsitektural Bernard Tschumi yang bermanfaat bagi preseden untuk kegiatan pendidikan dan profesional bidang atsitektur. Penelitian ini merujuk kepada pandangan bahwa objek-objek arsitektural dapat memiliki nilai yang sama dengan objek yang dihasilkan dari sebuah aktivitas yang bersifat pengulangan. Dan bahkan sengaja dibuat agar untuk seterusnya dapat diulangi lagi. Artinya, sebuah objek arsitektural bukan saja menghasilkan sebuah pengulangan, melainkan juga dihasilkan dari sebuah pengulangan. Penelitian ini mengggunakan metode content analysis dengan mempelajari pemikiran konsep dan metode desain arsitek Bernard Tschumi lewat literatur yang terbagi dalam:  Kelompok I, berupa karya-karya teoritis dari Bernard Tschumi dan Kelompok II, berupa karya-karya arsitektural. Hasil penelitian menemukan bahwa Bernard Tschumi mengungkapkan bahwa arsitektur adalah mengenai space (ruang), event (peristiwa) dan movement (pergerakan) yang disjunctive. Pendapat ini kemudian dimunculkan dalam beberapa konsep utama yang dapat dikelompokkan menjadi: 1) Space & event, 2) Plan, juxtaposition, overlay, 3) Vectors & Envelopes, 4) Concept, context, content, 5) Form – Concept. Dan untuk mengaplikasikan Teori dan konsep kedalam desain, Tschumi menggunakan beberapa metode yaitu: 1) Cross Programming; 2) Transprogramming; 3) Dispogramming; 4) Transformation; 5) Superimposition; 6) Combination; 7) Disjunction; 8) Cinegram-montage

    Inhibition of NF-κB activation by 5-lipoxygenase inhibitors protects brain against injury in a rat model of focal cerebral ischemia

    Get PDF
    BACKGROUND: Stroke is one of the leading causes of death worldwide and a major cause of morbidity and mortality in the United States of America. Brain ischemia-reperfusion (IR) triggers a complex series of biochemical events including inflammation. Leukotrienes derived from 5-lipoxygenase (5-LOX) cause inflammation and are thus involved in the pathobiology of stroke injury. METHODS: To test the neuroprotective efficacy of 5-LOX inhibition in a rat model of focal cerebral IR, ischemic animals were either pre- or post-treated with a potent selective 5-LOX inhibitor, (N- [3-[3-(-fluorophenoxy) phenyl]-1-methyl-2-propenyl]-N-hydroxyurea (BW-B 70C). They were evaluated at 24 h after reperfusion for brain infarction, neurological deficit score, and the expression of 5-LOX. Furthermore, the mechanism and the anti-inflammatory potential of BW-B 70C in the regulation of nuclear factor kappa B (NF-κB) and inflammatory inducible nitric oxide synthase (iNOS) were investigated both in vivo and in vitro. RESULTS AND DISCUSSION: Both pre- and post-treatment with BW-B 70C reduced infarctions and improved neurological deficit scores. Immunohistochemical study of brain sections showed IR-mediated increased expression of 5-LOX in the neurons and microglia. BW-B 70C down-regulated 5-LOX and inhibited iNOS expression by preventing NF-κB activation. Two other structurally different 5-LOX inhibitors were also administered post IR: caffeic acid and 2, 3, 5-trimethyl-6- [12-hydroxy-5, 10-dodecadiynyl]-1, 4-benzoquinone (AA-861). As with BW-B 70C, they provided remarkable neuroprotection. Furthermore, in vitro, BW-B 70C inhibited lipopolysaccharide (LPS) mediated nitric oxide production, iNOS induction and NF-κB activation in the BV2 microglial cell line. Treating rat primary microglia with BW-B70C confirmed blockage of LPS-mediated translocation of the p65 subunit of NF-κB from cytosol to nucleus. CONCLUSION: The study demonstrates the neuroprotective potential of 5-LOX inhibition through down-regulation of NF-κB in a rat model of experimental stroke

    Breast lesions and cancer: histopathology and molecular classification in a referral hospital in Ghana

    Get PDF
    Background: Histological diagnosis is crucial to the management of breast diseases. It determines the kind of disease, the treatment modalities, and the outcome of management. Our department receives breast biopsies from the northern sector of Ghana constituting over 50% of the Ghanaian population. This study aimed at elucidating the pattern of disease and associated traditional prognostic indices of breast cases in our department over a period of 9 years.Methods: Information on the demographic characteristics and the histological diagnoses made on all breast cases received and processed in the department were accessed and entered into an Excel spreadsheet. Slides were reviewed and IHC was done on suitable cases. Descriptive statistics were generated using IMB-SPSS version 23.Results: A total of 4276 breast cases were received by the department within the study period, with 97.6% being female. Age ranged (female/male) from 10 to 98/13 to 102 years, with mean ages of 38.2 years (SD ± 16.7) and 41.15 years (SD ± 21.6), respectively. Cases were evenly distributed in both left and right breasts and 4.3% were bilateral. Inflammatory conditions were seen in 7.5% of cases. The most diagnosed benign tumor was fibroadenoma (54%), followed by fibrocystic change (8.1%). Gynecomastia was diagnosed in 66.3% of males. Malignant cases were 38.6%, with invasive carcinoma NST being the most frequent (87.5%). Histological grades were I = 9.4%, II = 41.6%, and III = 49%. Molecular subtypes were luminal A (19.8%), luminal B (9.9%), Her2 (16%), and TNBC (54.3%).Conclusion: Our findings show an increase in breast cancer cases compared to previous studies in our center, suggesting increased awareness and improved diagnosis. However, this increase is consistent with most studies in sub-Saharan Africa
    corecore