251 research outputs found

    Explanation of the accelerated expansion of the universe and dark energy with irreversible thermodynamics∗

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    In this paper, by invoking the laws of irreversible thermody\ud namics the accelerated expansion of the universe is\ud explained. It is shown that the entropy of the universe, at an\ud y particular instant of time, plays a significant role\ud in the accelerated expansion of the universe. Considering t\ud he universe to be filled with a classical mono-atomic,\ud homogeneous and isotropic gas under classical non-equilib\ud rium situations, two generalized forces causing the\ud expansion of the universe are arrived at. One of the two force\ud s, the trivial force, has affinity to volume expansion\ud and the non-trivial force has affinity to spatial expansion.\ud The acceleration of the expansion of the universe is due\ud to the spatial expansion caused by the non-trivial force and\ud which in turn might account for the presence of the dark\ud energy. It is shown in this paper that the non-trivial genera\ud lized force and the dark energy, providing the negative\ud pressure for spatial expansion, can be explained with irrev\ud ersible thermodynamics

    Remote (Dis)engagement: Shifting Corporate Risk to the 'Bottom of the Pyramid'

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    Untapped markets are often deemed institutional voids, terra incognita ripe with economic possibility. The conversion of institutional voids into viable markets has become the ambition of many corporations today, which view marginal and under-served areas such as urban slums as opportunities to achieve the dual aims of market growth and poverty reduction, particularly through ‘bottom of the pyramid’ (BoP) programmes. This article examines how firms manage institutional voids and the consequences of these approaches for workers through a case study of a BoP ‘route to market’ programme designed by a global food manufacturer in Kibera, Africa's largest slum, located in Nairobi. Instead of engaging with Kibera by upgrading informal markets or generating formal employment, the corporation focused on harnessing existing informal systems through composite arrangements of NGOs, social networks and informal enterprises, a strategy the authors term ‘remote (dis)engagement’. The article describes the logics and outcome of this strategy of formal engagement with informal markets, concluding that the BoP business model depends on ‘gig practices’ of flexibility, irregular work and insecurity to realize the much-heralded ‘fortune at the bottom of the pyramid’

    Assessment of genetic and biochemical diversity of ecologically variant ectomycorrhizal Russula sp. from India

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    The aim of this study was to develop the phylogenetic relationship amongst the ecologically variant Russula species by using polymerase chain reaction (PCR) based technique, random amplified polymorphic DNA (RAPD) and isozyme analyses. Two groups could be characterized amongst the total isolates by cluster analyses. Protease, cellulase, glutamate dehydrogenase,  pectinase and acid phosphatase designated band P220.16, C472.18, GLD130.21, Pe569.12 and AP472.12, respectively, were common in all the isolates and four monomorphic RAPD bands viz; 818, 512, 298 and 201 bp were also diversified in the isolates. This common band reveals that diversity of these alleles or loci in all ecologically variant isolates. Thus, the present studies discuss the genetic diversity of ecologically variant Russula species on the basis of RAPD and isozyme analysis

    Development of 0.2C-CrMnMoV Ultra High Strength Steel

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    A study was carried out to develop a low alloy ultra high strength steel by induction melting and thermomechanical treatment (TMT) containing alloying elements like carbon, manganese, molybdenum, chromium and vanadium. A base alloy was prepared with 0.24%C, 1.16% Mn, 0.23% Si, 5.61% Cr, 0.42%V, 1.01% Mo, 0.026%S and 0.032%P. It showed tensile strength of 1467 MPa, yield strength of about 1180 MPa, impact strength of 6.3J and elongation of 5.9% in as-tempered condition. Other alloy was prepared by addition of 0.054% titanium with the base composition. It displayed tensile strength, yield strength, impact toughness and % elongation of 1615 MPa, 1240 MPa, 8.2J and 6.15%, respectively. The optical, SEM and TEM microstructures confirmed that the base alloy and the titanium alloy consisted with tempered lath martensites. The remaining part of the ingot was further processed by the thermomechanical treatment. The ingots were rolled in two passes, initially at 950 C and subsequently at 850 C followed by immediate cooling in oil. The TMT plates of the base alloy confirmed the tensile strength of 1755 MPa, yield strength in excess of 1460 MPa and impact strength of 9.1J. The titanium added TMT plate displayed tensile strength of 1860 MPa, yield strength of 1580 MPa and impact strength of 10.1J. Microstructures of titanium added alloy consisted finer lath martensite and precipitates of titanium carbides/carbonitrides. It was observed that the addition of titanium significantly improved the mechanical properties of 0.2C-Cr Mn Mo V alloys and the mechanical properties were also improved significantly by thermomechanical treatment

    The outcome of trachomatous trichiasis surgery in Ethiopia: risk factors for recurrence.

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    BACKGROUND: Over 1.2 million people are blind from trachomatous trichiasis (TT). Lid rotation surgery is the mainstay of treatment, but recurrence rates can be high. We investigated the outcomes (recurrence rates and other complications) of posterior lamellar tarsal rotation (PLTR) surgery, one of the two most widely practised TT procedures in endemic settings. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a two-year follow-up study of 1300 participants who had PLTR surgery, conducted by one of five TT nurse surgeons. None had previously undergone TT surgery. All participants received a detailed trachoma eye examination at baseline and 6, 12, 18 and 24 months post-operatively. The study investigated the recurrence rates, other complications and factors associated with recurrence. Recurrence occurred in 207/635 (32.6%) and 108/641 (16.9%) of participants with pre-operative major (>5 trichiatic lashes) and minor (5 lashes (major recurrence). Recurrence was greatest in the first six months after surgery: 172 cases (55%) occurring in this period. Recurrence was associated with major TT pre-operatively (OR 2.39, 95% CI 1.83-3.11), pre-operative entropic lashes compared to misdirected/metaplastic lashes (OR 1.99, 95% CI 1.23-3.20), age over 40 years (OR 1.59, 95% CI 1.14-2.20) and specific surgeons (surgeon recurrence risk range: 18%-53%). Granuloma occurred in 69 (5.7%) and notching in 156 (13.0%). CONCLUSIONS/SIGNIFICANCE: Risk of recurrence is high despite high volume, highly trained surgeons. However, the vast majority are minor recurrences, which may not have significant corneal or visual consequences. Inter-surgeon variation in recurrence is concerning; surgical technique, training and immediate post-operative lid position require further investigation

    PENGUJIAN KUAT TEKAN BETON YANG MENGGUNAKAN AGREGAT LOKAL DENGAN PEMANFAATAN ABU SEKAM PADI DAN BATU APUNG SEBAGAI SUBSTITUSI PARSIAL SEMEN

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    Penggunaan beton sebagai material pada struktur bangunan semakin meningkat. Gas emisi karbondioksida (CO2) dihasilkan saat proses pembuatan semen yang menimbulkan dampak buruk bagi lingkungan. Guna meminimalkan penggunaan semen portland dalam konstruksi sederhana dan memaksimalkan penggunaan limbah dari material alam, maka pemakaian semen jenis lain perlu dicoba. Abu sekam padi dan batu apung adalah contoh limbah yang mengandung oksida silika sebagai bahan utama penyusunnya, hal tersebut memberikan sifat pozzolanik sehingga dapat dimanfaatkan sebagi bahan substitusi parsial pada semen. Penelitian ini bertujuan untuk mengetahui pengaruh penambahan abu sekam padi dan batu apung sebagai pengganti sebagian semen terhadap kuat tekan beton. Metode ACI 211.1-91 digunakan untuk menghitung komposisi campuran beton. Pengujian kuat tekan beton dengan benda uji berbentuk silinder berdiameter 100 mm dan tinggi 200 mm. Pengujian dilakukan pada umur 14 hari dan 28 hari, dengan variasi sampel benda uji ASP, ASPBA1, ASPBA2,  ASPBA3,ASPBA4, dan ASPBA5.Hasil penelitian beton dengan substitusi parsial semen menunjukan bahwa kuat tekan yang paling optimum terdapat pada beton dengan substitusi parsial abu sekam padi 10%, dengan hasil 19,46 MPa pada umur 14 hari dan 23,44 MPa pada umur 28 hari. Kuat tekan beton mengalami peningkatan dengan presentase sebesar 20,45%. Kata Kunci: Pozzolan, Abu Sekam Padi, Batu Apung, Kuat Teka

    Remaking Africa's informal economies: youth, entrepreneurship and the promise of inclusion at the bottom of the pyramid

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    In recent years, the quest for 'inclusive markets' that incorporate Africa's youth has become a key focus of national and international development efforts, with so-called bottom of the pyramid (BoP) initiatives increasingly seen as a way to draw the continent's poor into new networks of global capitalism. SSA has become a fertile frontier for such systems, as capital sets its sights on the continents vast 'under-served' informal economies, harnessing the entrepreneurial mettle of youth to create new markets for a range of products, from solar lanterns and shampoo to cook stoves and sanitary pads. Drawing on ethnographic research with youth entrepreneurs, we trace the prcesses of individual and collective 'transformation' that the mission of (self-) empowerment through entrepreneurship seeks to bring about. We argue that, while such systems are meant to bring those below the poverty line above it, the 'line' is reified and reinforced through a range of discursive and strategic practices that actively construct and embed distinctions between the past and the future, valuable and valueless, and the idle and productive in Africa's informal economies

    Definitions and Standardization of a New Grading Scheme for Eyelid Contour Abnormalities after Trichiasis Surgery

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    Approximately 8 million individuals worldwide suffer from trichiasis, a condition characterized by in-turned lashes that rub against the eye. Trichiasis is caused by repeated or prolonged ocular infection with Chlamydia trachomatis. Surgery is available to correct in-turned lashes. In most programmatic and research settings, the primary determinant of surgical success is whether or not lashes are touching the globe post-operatively. However, other surgical outcomes such as the contour of the eyelid are also important. Yet, no standard method for evaluating and reporting this outcome has been defined. In this study, we developed and tested a grading system for evaluating the severity of eyelid contour abnormalities after surgery using photographs of eyelids six weeks post-operatively. We found good agreement across photograph graders and also between field and photograph grades. This system should be useful in helping to standardize reporting of this outcome

    Predictors of Trachomatous Trichiasis Surgery Outcome.

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    PURPOSE: Unfavorable outcomes after trachomatous trichiasis (TT) surgery are undermining the global trachoma elimination effort. This analysis investigates predictors of postoperative TT (PTT), eyelid contour abnormalities (ECAs), and granuloma in the 2 most common TT surgery procedures: posterior lamellar tarsal rotation (PLTR) and bilamellar tarsal rotation (BLTR). DESIGN: Secondary data analysis from a randomized, controlled, single-masked clinical trial. PARTICIPANTS: A total of 1000 patients with TT, with lashes touching the eye or evidence of epilation, in association with tarsal conjunctival scarring. METHODS: Participants were randomly allocated and received BLTR (n = 501) or PLTR (n = 499) surgery. Disease severity at baseline, surgical incisions, sutures, and corrections were graded during and immediately after surgery. Participants were examined at 6 and 12 months by assessors masked to allocation. MAIN OUTCOME MEASURES: Predictors of PTT, ECA, and granuloma. RESULTS: Data were available for 992 (99.2%) trial participants (496 in each arm). There was strong evidence that performing more peripheral dissection with scissors in PLTR (odd ratio [OR], 0.70; 95% confidence interval [CI], 0.54-0.91; P = 0.008) and BLTR (OR, 0.83; 95% CI, 0.72-0.96; P = 0.01) independently protected against PTT. Baseline major trichiasis and mixed location lashes and immediate postoperative central undercorrection independently predicted PTT in both surgical procedures. Peripheral lashes in PLTR (OR, 5.91; 95% CI, 1.48-23.5; P = 0.01) and external central incision height ≥4 mm in BLTR (OR, 2.89; 95% CI, 1.55-5.41; P = 0.001) were independently associated with PTT. Suture interval asymmetry of >2 mm (OR, 3.18; 95% CI, 1.31-7.70; P = 0.01) in PLTR and baseline conjunctival scarring in BLTR (OR, 1.72; 95% CI, 1.06-2.81; P = 0.03) were independently associated with ECA. Older age was independently associated with ECA in both PLTR (P value for trend < 0.0001) and BLTR (P value for trend = 0.03). There was substantial intersurgeon variability in ECA rates for both PLTR (range, 19.0%-36.2%) and BLTR (range, 6.1%-28.7%) procedures. In PLTR surgery, irregular posterior lamellar incision at the center of the eyelid (OR, 6.72; 95% CI, 1.55-29.04; P = 0.01) and ECA (OR, 3.08; 95% CI, 1.37-6.94; P = 0.007) resulted in granuloma formation. CONCLUSIONS: Poor postoperative outcomes in TT surgery were associated with inadequate peripheral dissection, irregular incision, asymmetric suture position and tension, inadequate correction, and lash location. Addressing these will improve TT surgical outcomes
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