114 research outputs found
Genome-wide association study for lung cancer in 6531 African Americans reveals new susceptibility loci
No full textAbstract Despite lung cancer affecting all races and ethnicities, disparities are observed in incidence and mortality rates among different ethnic groups in the United States. Non-Hispanic African Americans had a high incidence rate of lung cancer at 55.8 per 100 000 people, as well as the highest death rate at 37.2 per 100 000 people from 2016 to 2020. While previous genome-wide association studies (GWAS) have identified over 45 susceptibility risk loci that influence lung cancer development, few GWAS have investigated the etiology of lung cancer in African Americans. To address this gap in knowledge, we conducted GWAS of lung cancer focused on studying African Americans, comprising 2267 lung cancer cases and 4264 controls. We identified three loci associated with lung cancer, one with lung adenocarcinoma, and four with lung squamous cell carcinoma in this population at the genomic-wide significance level. Among them, three novel loci were identified near VWF at 12p13.31 for overall lung cancer and GACAT3 at 2p24.3 and LMAN1L at 15q24.1 for lung squamous cell carcinoma. In addition, we confirmed previously reported risk loci with known or new lead variants near CHRNA5 at 15q25.1 and CYP2A6 at 19q13.2 associated with lung cancer and TRIP13 at 5p15.33 and ERC1 at 12p13.33 associated with lung squamous cell carcinoma. Further multi-step functional analyses shed light on biological mechanisms underlying these associations of lung cancer in this population. Our study highlights the importance of ancestry-specific studies for the potential alleviation of lung cancer burden in African Americans
Rent - seeking trade policy : a time series approach
No full textUsing a time-series approach, the author analyzes the relationship between the extent of rent-seeking trade policy and both political and economic variables. For rent-seeking trade policy, the indicator he uses is the number of foreign-trade regulations passed each year for the benefit of a single firm or industry. The author uses data from Uruguay for 1925-83. Uruguay, which experienced an impressive economic decline, is an outstanding example of a rent-seeking society. After being a wealthy economy in midcentury, it suffered almost complete stagnation, which led to social and policital disintegration by the end of the 1960s. Three decades of restrictive regulations on foreign trade had created a nearly closed economy by the end of the 1960s. It was worth analyzing whether policymakers'great receptiveness to demands for protection could account for Uruguay's decline. Over the period 1925-83, the author finds almost 4,000 laws, decrees, and administrative resolutions that create, maintain, or modify a foreign-trade regulation for the benefit of a single firm or industry. About half of them explicitly identify the petitioner - usually a firm or guild. Since the size of the Uruguayan economy changed over the period studied, the author scales the annual number of regulations by output or exports to measure the extent of rent-seeking trade policy. The author shows that the extent of rent-seeking trade policy increased with discretionary policies and under dictatorship. (In the period studied, there were two stages of democracy - until 1932 and from 1943-72 - and two stages of dictatorship.) He also shows that rent-seeking trade restrictions increased under import-substitution strategies and, more unexpectedly, under active export promotion. This suggests that discretionary power leads to wasteful distribution, whether it is used to support inward- or outward-oriented policies. Finally, the author analyzes the correlation between innovations in the trade policy indicator and innovations in the growth rates of output and exports, with a lag of up to 20 years. Surprisingly, he finds a positive correlation with output growth rates after two or three years. But the correlation becomes negative some years later, particularly in the case of exports. The short-run positive impact on growth rates, together with the surprisingly long time lag before the negative impact, may account for policymakers'receptiveness to demands for protection.Trade Policy,Achieving Shared Growth,TF054105-DONOR FUNDED OPERATION ADMINISTRATION FEE INCOME AND EXPENSE ACCOUNT,Economic Theory&Research,Environmental Economics&Policies
Scientometric Portrait of Homi Jehangir Bhabha: The Father of Indian Nuclear Research Programme
No full textQuantitative and qualitative analysis with graphic representation of the publication productivity of a scientist facilitates easy and clear perception about the work of a scientist. Bhabha’s scientific work spanned over more than three decades (1933-1967) during which he published 104 publications, which could be classified into nine fields: Interaction of Radiation with Matter (4), Quantum Electrodynamics (5), Mathematical Physics (2), Cosmic Ray Physics (18), Elementary Particle Physics (14), Field Theory (15), General Physics (2), Nuclear Physics (4) and General (40). The highest number of publications (6) were published in 1941, 1945 and 1964 respectively. The average number of publications published per year was 3.05. His productivity coefficient was 0.05 which is a clear indicates that his publication productivity was quite consistent throughout his scientific career. He was single author in 79 of his publications and the main author in 24 publications indicates that he always preferred to work himself and lead the team as ‘mentor’. Bhabha had 22 collaborators during the period. Team of research collaborators working with a successful scientist documents the sociological aspect of history of science while generating knowledge by a leader in a domain.
Bhabha became a citable author in 1937. Bhabha received 1211 citations to his 30 publications out of 104 publications. Out of 104, 74 publications did not receive any citations. Out of 74 publications, 40 publications dealt subjects mainly of general interest. Bhabha’s 86.66 percent of cited publications received their first citations within four years of their publication indicates that his publications were noticed immediately and had direct impact among the fellow researchers working all over the world. His overall citation rate was 11.64 per cited publication. The highest citations 389 were received to the domain ‘Cosmic ray physics’. The highest number of citations received were 45 in 1938. His self-citations were only 24 (1.98%) and citations by others were 1187 (98.02%). The highest self citations were six in 1946. Bhabha’s mean diachronous self-citation rate was 1.98. The highest citation rate 28.4 was to the domain ‘Quantum electrodynamics. His single authored publications have received the highest number 863 (71.26%) of citations. Bhabha’s five publications have been cited more than 100 times each. His publications have been cited by the authors working in various diverse fields like nuclear physics, mathematical physics, instrumentation, optics, geophysics and geochemistry, condensed matter physics, applied physics, electrical and electronic engineering, mechanical engineering etc., indicating a very diverse influence and impact of Bhabha’s publications. Bhabha’s publications have also been cited by the Nobel laureates like V. L. Ginzberg, Wolfgang Pauli, H. A. Bethe, M. Born, W. Bothe, E. P. Wigner, H. Yukawa, P. M. S. Blackett and C. N. Yang which is an indication of his originality of ideas and high quality of publications
Scientometric portrait of Nobel laureate Leland H. Hartwell
No full textLeland H. Hartwell was honoured with the Nobel Prize in Physiology or Medicine (2001) at his 62 years age and at 41 years of research publishing career. The first contribution of the author was in 1961 at the age of 22. The number of his contributions in a year peaked in 1997 when it touched 8. He had 108 publications during 1961 – 2001 in domains: Molecular Biology of Cell Cycle Regulation (43), Genetics of Cell Division (48), Genomic Re-arrangement and DNA Repair (9), Molecular Genetics of Yeast Cell Fission (5), and Drug Target Interaction (3) which were analysed for authorship pattern with his 101 collaborators. Most active researchers having number of publications with Leland H. Hartwell were : Weinert, T. A. (10), Garvik, B. M. (8), McLaughlin, C. S. (8), Jenness, D. D. (5). His productivity coefficient was 0.76 which clearly indicates that his productivity increased after 50 percentile age. Highest collaboration coefficient (1) for Leland H. Hartwell was found during 1963-1965, 1968-1969, 1977, 1981-1983, 1985-1990, 1996 and 1998-2001. Journals have been the most preferred channel of communication where, as many as 96 papers out of 108 have been published. The core journals publishing his papers were: Cell (14), Genetics (12), Mol. Cell Biol. (8), J. Bactariol. (7), J. Cell Biol. ( 7), Science (7) J. Mol. Biol.(6), Exp. Cell Res. (5), and Proc. Nat. Acad. Sci.(5). Publication density is 2.63 and Publication concentration is 14.63. Most prolific keywords in titles of publications were: Saccharomyces cerevisiae , Yeast , Cell division cycle , RAD9, DNA Damage , Genes , Cell cycle, Genetic control , Check point (s) , Cell division , Mutant of Yeast
Multiscale Investigation of Shape Memory Alloy Fatigue
No full textShape memory alloys (SMAs) are functional materials with two remarkable properties: superelasticity and the shape memory effect. The reversible, solid-to-solid ("martensitic") phase transformations that enable these useful material responses also complicate their durability predictions. SMAs are used extensively in biomedical devices such as stents and root canal files, and also have promising applications for important frontiers, such as weight-saving actuators, active structures for aerospace systems, and damping components for civil structures. Before SMAs can be widely adopted for these new applications, however, their response to cracking and failure must be understood. Complexities from martensitic phase transformations in SMAs confound many existing predictions of damage, fatigue, and fracture mechanics (including Schmid's Law and linear/elastoplastic fracture mechanics). Furthermore, this work's findings could extend to other emerging materials with phase transformations, such as Heusler alloys for high-efficiency magnetocaloric refrigeration.
To address these knowledge gaps, this work provides new observations and insights on the role of phase transformation during cracking and failure of SMAs. Additionally, new experimental frameworks were developed to characterize cracks in structural materials for unprecedented breadth and precision between the millimeter and nanometer length scales.
The early part of this work optimized full-field deformation measurements to enable the high-precision experiments of the later part of this work. Also, it advanced techniques in the broader experimental mechanics community. First, a new method was developed to enhance measurements from digital image correlation (DIC), a powerful technique for measuring material deformation. Also, clear guidelines were presented for optimizing an important sample preparation step for optical DIC ("speckle patterning" with paint)
The latter part of this work established new insights into SMA cracking by examining the effects of grain size, crystallographic texture, and temperature. There are two types of fatigue in SMAs: functional fatigue (degradation of the phase transformation, especially from reduction in the recovered strain during superelastic cycling), and structural fatigue (the typical fatigue response of metals, with crack initiation and growth). Despite the dramatic enhancement of NiTi's functional fatigue resistance with grain size reduction to the nanoscale, there was no improvement in structural fatigue resistance with respect to grain size. Rather, the largest grain size studied had the slowest crack growth rate, which was attributed to roughness-induced crack closure (not observed in the other grain sizes). For all grain sizes, the macroscopic fatigue crack growth correlated well with microscopic crack tip observations: the grain sizes with relatively fast macroscopic crack growth rates exhibited large crack displacements at the microscale, and vice versa.
Next, the effects of crystallographic texture on NiTi's functional and structural fatigue were characterized. Unlike the grain size study that was complicated by roughness-induced crack closure differences, the three texture conditions had similar fracture surface. Furthermore, there were clear connections between functional and structural fatigue. During cyclic tension, there was about three times as much residual strain accumulation in the sheet's rolling direction (RD) compared to the transverse direction (TD), and the crack growth rates of the RD condition were consistently faster than the 45 and TD conditions.
Finally, fatigue experiments as a function of temperature characterized the role of martensitic phase transformation on cracking. The slowest crack growth rates were measured in the stable martensite and thermal R-phase martensite.PhDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/146027/1/wlepage_1.pd
Voucher funds in transitional economies : the Czech and Slovak experience
No full textVoucher funds have arisen in the transitional economies of Eastern and Central Europe that have used voucher privatization. These funds collect vouchers from citizens and use them to buy shares in enterprises. In the Czech and Slovak Republics, voucher funds are typically organized as corporations owned by the citizens who contributed their vouchers. Recently, they have also been organized as unit trusts (either open-ended or closed). A management company manages the funds under a contract that specifies the management fee. The management company is typically owned by the initial sponsor of the fund - for example, a bank. Voucher funds can give owners a diversified and professionally managed portfolio. More important, the funds select who sits on an enterprise's governance boards (which oversee management and profitability). Although experience is limited, the funds in these two countries have probably stopped most fraud and self-serving by enterprise mangers and are beginning to encourage the restructuring needed for profitability. A few funds have replaced poorly performing or dishonest managers; more often, because qualified replacements are few, they encourage managers to improve performance. There have been complaints about funds'performance. Some have made unrealistic promises to voucher holders and have appointed poorly qualified members to management boards. There is concern about conflicts of interest in the bank-sponsored funds and excessive control of enterprises. Funds typically lack capital or expertise to undertake restructuring - but few other potential owners are likely to be better qualified. The author examines 27 regulations that have been proposed for funds. Regulations in transitional economies, unlike regulations in most western countries, should encourage funds to play a strong role in corporate governance, he contends, as few potential owners have this ability. Most important, regulations should require that funds disclose information about their operations so their owners can monitor and control fund managers. The regulatory regime, the author says, should discourage monopolies and anticompetitive behavior; create incentives for fund managers to improve fund performance; discourage self-serving or fraudulent behavior by fund managers, and conflicts of interest; and eliminate high-risk investments unacceptable to fund owners. Because there is so little experience with these funds, the regulatory regime should not be unduly restrictive. As problems arise, regulations to deal with them can be added.International Terrorism&Counterterrorism,Economic Adjustment and Lending,Economic Theory&Research,Agricultural Knowledge&Information Systems,Payment Systems&Infrastructure
Physics Nobel laureate Wolfgang Ketterle : a scientometric portrait
No full textWolfgang Ketterle was honoured with the Nobel Prize in Physics (2001) at 44 years of biological age and at 20 years of research publishing career. He had 115 publications during 1982 – 2002 in domains: Bose-Einstein Condensation (68), Laser Spectroscopy (30), and Atomic Physics (17) which were analysed for authorship pattern with his 68 collaborators. Most active researchers having number of publications with Wolfgang Ketterle were : S. Inouye (26), A. P. Chikkatur (20), M. R. Andrews (19), D. M. Stampur-Kurn (18), D. S. Durfee (17), H. J. Miesner (17), D. E. Pritchard (17), H. Walther (12), M. O. Mewes (12), D. M. Kurn (12), C. Raman (12), J. Stenger (12), J. Wolfrum (11), A. Arnold (10), N. J. van Druten (10), A. Gorlitz (10), and S. Gupta (10). His productivity coefficient was 0.78 which clearly indicates that his productivity increased after 50 percentile age. Highest collaboration coefficient (1) for Wolfgang Ketterle was found in 1983-1985, 1988, 1991-1995, and 2001. The publication concentration was 5.21% and publication density was 2.01. The core journals publishing his papers were: Phys. Rev. Lett. (30), Applied Physics-B (7), Journal of Chemical Physics (5), Nature (5), Physics Review-A (5), and Science (5). Most prolific keywords in titles were: Bose-Einstein condensate (38), Bose-Einstein condensation (15), Observation (9), Helium hydride (8), Emission spectrum, (6) Suppression (4). The ‘biobibliometrics’ term is used for a method of retrieving and visualizing biological information that uses co-occurrence of gene naming terms in Medical Sciences to generate semantic links between genes. Therefore it is suggested that ‘Scientometric Portrait’ is the appropriate phrase for the studies on scientists and ‘Informetric Portrait’ for the studies pertaining to researchers in other disciplines such as arts, humanities, and social sciences
Gel cast molding with fugitive molds, U.S. Patent 5,824,250
No full textA ceramic component is manufactured rapidly using a mold made directly from a solid freeform manufacturing process. Solid freeform fabrication, or rapid prototyping, procedures are used to generate molds of materials that are soluble or otherwise fugitive. A gel casting suspension containing ceramic and emulsifying agents is poured into the cavity of the mold and caused to set. The mold is then removed by dissolution or heat treatment, leaving intact the gelcast part. Conventional procedures are then utilized to densify the gelcast component to the required final component. Time consuming and expensive machine tooling procedures are virtually eliminated. Ceramic components are generated rapidly in a cost effective manner
H. J. Bhabha : a case study of synchronous references
No full textQuantitative analysis of the events of synchronous references in the research papers followed throughout the publishing career of an individual scientist revealed interesting highlights on the knowledge-generating-system. In the case study of Homi Jehangir Bhabha first quinquennium and fifth quinquennium of his research career had low Self-references; third quinquennium and fourth quinquennium had moderate Self-references; whereas second quinquennium had highest Self-references. The two major clusters of Self-references occurring during the second and third quinquennium were indicators of active periods of knowledgegenerating and faster communications.(Revised version published in 2006 in International Journal of Nuclear Knowledge Management,Vol.2. No.1. pp.14-30. see PDF2
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