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S Bisterzo - One of the best experts on this subject based on the ideXlab platform.
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galactic chemical evolution and solar s Process abundances dependence on the 13c pocket structure
The Astrophysical Journal, 2014Co-Authors: S Bisterzo, C Travaglio, Roberto Gallino, Michael Wiescher, F KappelerAbstract:We study the s-Process abundances (A 90) at the epoch of the solar system formation. Asymptotic giant branch yields are computed with an updated neutron capture network and updated initial solar abundances. We confirm our previous results obtained with a Galactic chemical evolution (GCE) model: (1) as suggested by the s-Process Spread observed in disk stars and in presolar meteoritic SiC grains, a weighted average of s-Process strengths is needed to reproduce the solar s distribution of isotopes with A > 130; and (2) an additional contribution (of about 25%) is required in order to represent the solar s-Process abundances of isotopes from A = 90 to 130. Furthermore, we investigate the effect of different internal structures of the 13C pocket, which may affect the efficiency of the 13C(α, n)16O reaction, the major neutron source of the s Process. First, keeping the same 13C profile adopted so far, we modify by a factor of two the mass involved in the pocket; second, we assume a flat 13C profile in the pocket, and we test again the effects of the variation of the mass of the pocket. We find that GCE s predictions at the epoch of the solar system formation marginally depend on the size and shape of the 13C pocket once a different weighted range of 13C-pocket strengths is assumed. We obtain that, independently of the internal structure of the 13C pocket, the missing solar system s-Process contribution in the range from A = 90 to 130 remains essentially the same.
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galactic chemical evolution and solar s Process abundances dependence on the 13c pocket structure
arXiv: Solar and Stellar Astrophysics, 2014Co-Authors: S Bisterzo, C Travaglio, Roberto Gallino, Michael Wiescher, F KappelerAbstract:We study the s-Process abundances (A > 90) at the epoch of the solar-system formation. AGB yields are computed with an updated neutron capture network and updated initial solar abundances. We confirm our previous results obtained with a Galactic Chemical Evolution (GCE) model: (i) as suggested by the s-Process Spread observed in disk stars and in presolar meteoritic SiC grains, a weighted average of s-Process strengths is needed to reproduce the solar s-distribution of isotopes with A > 130; (ii) an additional contribution (of about 25%) is required in order to represent the solar s-Process abundances of isotopes from A = 90 to 130. Furthermore, we investigate the effect of different internal structures of the 13C-pocket, which may affect the efficiency of the 13C(a, n)16O reaction, the major neutron source of the s-Process. First, keeping the same 13C profile adopted so far, we modify by a factor of two the mass involved in the pocket; second, we assume a flat 13C profile in the pocket, and we test again the effects of the variation of the mass of the pocket. We find that GCE s-predictions at the epoch of the solar-system formation marginally depend on the size and shape of the 13C-pocket once a different weighted range of 13C-pocket strengths is assumed. We ascertain that, independently of the internal structure of the 13C-pocket, the missing solar-system s-Process contribution in the range from A = 90 to 130 remains essentially the same.
F Kappeler - One of the best experts on this subject based on the ideXlab platform.
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galactic chemical evolution and solar s Process abundances dependence on the 13c pocket structure
The Astrophysical Journal, 2014Co-Authors: S Bisterzo, C Travaglio, Roberto Gallino, Michael Wiescher, F KappelerAbstract:We study the s-Process abundances (A 90) at the epoch of the solar system formation. Asymptotic giant branch yields are computed with an updated neutron capture network and updated initial solar abundances. We confirm our previous results obtained with a Galactic chemical evolution (GCE) model: (1) as suggested by the s-Process Spread observed in disk stars and in presolar meteoritic SiC grains, a weighted average of s-Process strengths is needed to reproduce the solar s distribution of isotopes with A > 130; and (2) an additional contribution (of about 25%) is required in order to represent the solar s-Process abundances of isotopes from A = 90 to 130. Furthermore, we investigate the effect of different internal structures of the 13C pocket, which may affect the efficiency of the 13C(α, n)16O reaction, the major neutron source of the s Process. First, keeping the same 13C profile adopted so far, we modify by a factor of two the mass involved in the pocket; second, we assume a flat 13C profile in the pocket, and we test again the effects of the variation of the mass of the pocket. We find that GCE s predictions at the epoch of the solar system formation marginally depend on the size and shape of the 13C pocket once a different weighted range of 13C-pocket strengths is assumed. We obtain that, independently of the internal structure of the 13C pocket, the missing solar system s-Process contribution in the range from A = 90 to 130 remains essentially the same.
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galactic chemical evolution and solar s Process abundances dependence on the 13c pocket structure
arXiv: Solar and Stellar Astrophysics, 2014Co-Authors: S Bisterzo, C Travaglio, Roberto Gallino, Michael Wiescher, F KappelerAbstract:We study the s-Process abundances (A > 90) at the epoch of the solar-system formation. AGB yields are computed with an updated neutron capture network and updated initial solar abundances. We confirm our previous results obtained with a Galactic Chemical Evolution (GCE) model: (i) as suggested by the s-Process Spread observed in disk stars and in presolar meteoritic SiC grains, a weighted average of s-Process strengths is needed to reproduce the solar s-distribution of isotopes with A > 130; (ii) an additional contribution (of about 25%) is required in order to represent the solar s-Process abundances of isotopes from A = 90 to 130. Furthermore, we investigate the effect of different internal structures of the 13C-pocket, which may affect the efficiency of the 13C(a, n)16O reaction, the major neutron source of the s-Process. First, keeping the same 13C profile adopted so far, we modify by a factor of two the mass involved in the pocket; second, we assume a flat 13C profile in the pocket, and we test again the effects of the variation of the mass of the pocket. We find that GCE s-predictions at the epoch of the solar-system formation marginally depend on the size and shape of the 13C-pocket once a different weighted range of 13C-pocket strengths is assumed. We ascertain that, independently of the internal structure of the 13C-pocket, the missing solar-system s-Process contribution in the range from A = 90 to 130 remains essentially the same.
Karen M Tani - One of the best experts on this subject based on the ideXlab platform.
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administrative equal protection federalism the fourteenth amendment and the rights of the poor
Cornell Law Review, 2015Co-Authors: Karen M TaniAbstract:This Article intervenes in a burgeoning literature on “administrative constitutionalism,” the phenomenon of federal agencies—rather than courts—assuming significant responsibility for elaborating the meaning of the U.S. Constitution. Drawing on original historical research, I document and analyze what I call “administrative equal protection”: interpretations of the Fourteenth Amendment’s Equal Protection Clause in a key federal agency at a time when the Clause’s meaning was fiercely contested. These interpretations are particularly important because of their interplay with cooperative federalism—specifically, with states’ ability to exercise their traditional police power after accepting federal money. The Article’s argument is based on a story of change over time. In the late 1930s, when federal courts appeared reluctant to vindicate equal protection claims, the Federal Social Security Board (later to become part of the Department of Health, Education and Welfare) took a more active role via its administration of federal grants for state-run public welfare programs. Through the 1940s and 1950s, agency lawyers developed and applied a nondeferential rationality model of equal protection to assess state welfare rules. When paired with the agency’s control over generous federal subsidies, this interpretation had tangible consequences: administrators challenged some of the era’s most restrictive state welfare laws and, in the Process, Spread the notion that poor Americans had constitutional rights, including under the Fourteenth Amendment. In the mid-1960s, as the agency became embroiled in battles over school desegregation, administrators deftly recharacterized their constitutional interpretation as a statutory one. They saw their constitutional arguments take on new life, however, as welfare rights advocates (including former agency personnel) wielded them in court. Both developments are visible in the landmark case King v. Smith (1968). There
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administrative equal protection federalism the fourteenth amendment and the rights of the poor
2015Co-Authors: Karen M TaniAbstract:This Article intervenes in a burgeoning literature on “administrative constitutionalism,” the phenomenon of federal agencies — rather than courts — assuming significant responsibility for elaborating the meaning of the U.S. Constitution. Drawing on original historical research, I document and analyze what I call “administrative equal protection”: interpretations of the Fourteenth Amendment’s Equal Protection Clause in a key federal agency at a time when the Clause’s meaning was fiercely contested. These interpretations are particularly important because of their interplay with cooperative federalism — specifically, with states’ ability to exercise their traditional police power after accepting federal money.The Article’s argument is based on a story of change over time. In the late 1930s, when federal courts appeared reluctant to vindicate equal protection claims, the federal Social Security Board (later to become part of the Department of Health, Education and Welfare) took a more active role via its administration of federal grants for state-run public welfare programs. Through the 1940s and 1950s, agency lawyers developed and applied a nondeferential rationality model of equal protection to assess state welfare rules. When paired with the agency’s control over generous federal subsidies, this interpretation had tangible consequences: administrators challenged some of the era’s most restrictive state welfare laws and, in the Process, Spread the notion that poor Americans had constitutional rights, including under the Fourteenth Amendment. In the mid 1960s, as the agency became embroiled in battles over school desegregation, administrators deftly recharacterized their constitutional interpretation as a statutory one. They saw their constitutional arguments take on new life, however, as welfare rights advocates (including former agency personnel) wielded them in court. Both developments are visible in the landmark case King v. Smith (1968). There the Supreme Court affirmed the poor claimants’ victory in the court below, but rejected the lower court’s equal protection holding in favor of one grounded in the agency’s novel statutory interpretation. Administrative equal protection thus continued to operate as a meaningful constraint on state action — and in fact helped remake the administration of American poor relief in the late twentieth century — but remained hidden from view.In addition to giving content and direction to the study of administrative constitutionalism, this history enriches legal scholarship in three ways: (1) it provides context for the “new federalism” revolution of the last decades of the twentieth century; (2) it opens up new questions about today’s “uncooperative federalism”; and (3) it helps explain the penurious protections that today’s equal protection jurisprudence offers the poor.
Robert Bogdan Staszewski - One of the best experts on this subject based on the ideXlab platform.
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a 1 v bandgap reference in 7 nm finfet with a programmable temperature coefficient and inaccuracy of 0 2 from 45 c to 125 c
IEEE Journal of Solid-state Circuits, 2019Co-Authors: Umanath R Kamath, Edward Cullen, John K Jennings, Peng Lim, Brendan Farley, Robert Bogdan StaszewskiAbstract:We present a 1-V precision voltage reference with a programmable temperature coefficient (“ temp-co ”). The voltage reference is based on a parasitic bipolar junction transistor (BJT) realized within the Process steps available in the chosen 7-nm FinFET technology. Details of its characterization and SPICE modeling are presented to provide insight into key device–circuit optimization choices. The trimming techniques needed to cope with Process Spread together with two curvature compensation techniques are presented. The reference achieves a maximum inaccuracy of ±0.2% and a minimum temp-co of 6 ppm/°C from −45°C to 125°C. Furthermore, its temp-co is digitally programmable between −7 mV/100°C and +8 mV/100°C. Its line regulation is 0.1%/V, and it occupies 0.078 mm2.
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bjt device and circuit co optimization enabling bandgap reference and temperature sensing in 7 nm finfet
European Solid-State Device Research Conference, 2018Co-Authors: Umanath R Kamath, Edward Cullen, John K Jennings, Peng Lim, Brendan Farley, Wei Yao, Robert Bogdan StaszewskiAbstract:Caused by the increased power density and strong thermal gradients in today's large SoC/FPGAs in scaled Process technologies, high-precision bandgap references and temperature sensors have become some of the most critical analog blocks. BJT devices form core components of such benchmark analog circuitry, thanks to their linear dependence on temperature. This paper discusses BJT device modeling and characterization results in 7-nm FinFET CMOS technology with regard to the BJT's variability and Process Spread. It provides guidance useful for the circuit implementation and quantifies the circuit application performance. Two test-chip device arrays are presented to demonstrate the feasibility of using BJTs in FinFET CMOS. A bandgap reference circuit is designed using the developed SPICE model. It shows measured max inaccuracy of $\pm \pmb{0.2\%}$ . The presented merged layout structure further saves 20% of area.
Sanjib Kumar Ghosh - One of the best experts on this subject based on the ideXlab platform.
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evolution of illustrations in anatomy a study from the classical period in europe to modern times
Anatomical Sciences Education, 2015Co-Authors: Sanjib Kumar GhoshAbstract:Illustrations constitute an essential element of learning anatomy in modern times. However it required a significant evolutionary Process Spread over centuries, for illustrations to achieve the present status in the subject of anatomy. This review article attempts to outline the evolutionary Process by highlighting on the works of esteemed anatomists in a chronological manner. Available literature suggests that illustrations were not used in anatomy during the classical period when the subject was dominated by the descriptive text of Galen. Guido da Vigevano was first to use illustrations in anatomy during the Late Middle Ages and this concept developed further during the Renaissance period when Andreas Vesalius pioneered in illustrations becoming an indispensable tool in conveying anatomical details. Toward later stages of the Renaissance period, Fabricius ab Aquapendente endeavored to restrict dramatization of anatomical illustrations which was a prevalent trend in early Renaissance. During the 18th century, anatomical artwork was characterized by the individual styles of prominent anatomists leading to suppression of anatomical details. In the 19th century, Henry Gray used illustrations in his anatomical masterpiece that focused on depicting anatomical structures and were free from any artistic style. From early part of the 20th century medical images and photographs started to complement traditional handmade anatomical illustrations. Computer technology and advanced software systems played a key role in the evolution of anatomical illustrations during the late 20th century resulting in new generation 3D image datasets that are being used in the 21st century in innovative formats for teaching and learning anatomy. Anat Sci Educ 8: 175–188. V C 2014 American Association of Anatomists.
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evolution of illustrations in anatomy a study from the classical period in europe to modern times
Anatomical Sciences Education, 2015Co-Authors: Sanjib Kumar GhoshAbstract:Illustrations constitute an essential element of learning anatomy in modern times. However it required a significant evolutionary Process Spread over centuries, for illustrations to achieve the present status in the subject of anatomy. This review article attempts to outline the evolutionary Process by highlighting on the works of esteemed anatomists in a chronological manner. Available literature suggests that illustrations were not used in anatomy during the classical period when the subject was dominated by the descriptive text of Galen. Guido da Vigevano was first to use illustrations in anatomy during the Late Middle Ages and this concept developed further during the Renaissance period when Andreas Vesalius pioneered in illustrations becoming an indispensable tool in conveying anatomical details. Toward later stages of the Renaissance period, Fabricius ab Aquapendente endeavored to restrict dramatization of anatomical illustrations which was a prevalent trend in early Renaissance. During the 18th century, anatomical artwork was characterized by the individual styles of prominent anatomists leading to suppression of anatomical details. In the 19th century, Henry Gray used illustrations in his anatomical masterpiece that focused on depicting anatomical structures and were free from any artistic style. From early part of the 20th century medical images and photographs started to complement traditional handmade anatomical illustrations. Computer technology and advanced software systems played a key role in the evolution of anatomical illustrations during the late 20th century resulting in new generation 3D image datasets that are being used in the 21st century in innovative formats for teaching and learning anatomy.