5,124 research outputs found
Kantian Nonideal Theory and Nuclear Proliferation
Recent revelations of Iranâs hitherto undisclosed uranium enrichment programs
have once again incited western fears that Tehran seeks nuclear weaponsâ
capability. Their fears seem motivated by more than the concern for compliance
with the Nuclear Nonproliferation Treaty (NPT). Rather, they seem strongly
connected to the western moral assumptions about what kind of government or
people can be trusted with a nuclear arsenal. In this paper, I critically examine
the western assumptions of the immorality of contemporary nuclear proliferation
from an international ethical stance that otherwise might be expected to give it
unequivocal support â the stance of Kantian nonideal theory. In contrast to the
uses of Kant that were prominent during the Cold War, I advance and apply
a sketch of a Kantian nonideal theory that specifies the conditions (although
strict conditions) under which nuclear proliferation for states like Iran is
morally permissible even though the NPT forbids it
Programmable Automated Welding System (PAWS): Control of welding through software and hardware
The ATD phase of the PAWS program ended in November 1992 and the follow-on ManTech program was started in September 1993. The system will be industrially hardened during the first year of this program. Follow-on years will focus upon the transition into specific end-user sites. These implementations will also expand the system into other welding processes (e.g. FCAW, GTAW, PAW). In addition, the architecture is being developed for application to other non-welding robotic processes (e.g. inspection, surface finishing). Future development is anticipated to encompass hardening for extreme environments, expanded exception handling techniques, and application to a range of manipulators
Reviving Nuclear Ethics: A Renewed Research Agenda for the Twenty-First Century
Since the end of the Cold War, international ethicists have focused largely on issues outside the traditional scope of security studies. The nuclear ethics literature needs to be revived and reoriented to address the new and evolving 21st century nuclear threats and policy responses
Liberal democracy and nuclear despotism: two ethical foreign policy dilemmas
This article advances a critical analysis of John Rawls's justification of liberal democratic nuclear deterrence in the post-Cold War era as found in The Law of Peoples. Rawls's justification overlooked how nuclear-armed liberal democracies are ensnared in two intransigent ethical dilemmas: one in which the mandate to secure liberal constitutionalism requires both the preservation and violation of important constitutional provisions in domestic affairs, and the other in which this same mandate requires both the preservation and violation of the liberal commitment to international legal arrangements and to the rule of law generally. On this view, the choice to violate constitutional provisions and international legal arrangements is evidence of nuclear despotism. Moreover, this choice does not imply that the ethical foreign policy dilemmas were resolved. Instead, it implies that the dilemmas force liberal democratic governments into implementing ethically paradoxical policy outcomes
Observation of Quantum Effects in sub Kelvin Cold Reactions
There has been a long-standing quest to observe chemical reactions at low
temperatures where reaction rates and pathways are governed by quantum
mechanical effects. So far this field of Quantum Chemistry has been dominated
by theory. The difficulty has been to realize in the laboratory low enough
collisional velocities between neutral reactants, so that the quantum wave
nature could be observed. We report here the first realization of merged
neutral supersonic beams, and the observation of clear quantum effects in the
resulting reactions. We observe orbiting resonances in the Penning ionization
reaction of argon and molecular hydrogen with metastable helium leading to a
sharp increase in the absolute reaction rate in the energy range corresponding
to a few degrees kelvin down to 10 mK. Our method is widely applicable to many
canonical chemical reactions, and will enable a breakthrough in the
experimental study of Quantum Chemistry
Genetic diversity of the rain tree (Albizia saman) in Colombian seasonally dry tropical forest for informing conservation and restoration interventions
Albizia saman is a multipurpose tree species of seasonally dry tropical forests (SDTFs) of Mesoamerica and northern South America typically cultivated in silvopastoral and other agroforestry systems around the world, a trend that is bound to increase in light of multimillion hectare commitments for forest and landscape restoration. The effective conservation and sustainable use of A. saman requires detailed knowledge of its genetic diversity across its native distribution range of which surprisingly little is known to date. We assessed the genetic diversity and structure of A.saman across twelve representative locations of SDTF in Colombia, and how they may have been shaped by past climatic changes and human influence. We found four different genetic groups which may be the result of differentiation due to isolation of populations in preglacial times. The current distribution and mixture of genetic groups across STDF fragments we observed might be the result of range expansion of SDTFs during the last glacial period followed by range contraction during the Holocene and humanâinfluenced movement of germplasm associated with cattle ranching. Despite the fragmented state of the presumed natural A. saman stands we sampled, we did not find any signs of inbreeding, suggesting that gene flow is not jeopardized in humanized landscapes. However, further research is needed to assess potential deleterious effects of fragmentation on progeny. Climate change is not expected to seriously threaten the in situ persistence of A. saman populations and might present opportunities for future range expansion. However, the sourcing of germplasm for tree planting activities needs to be aligned with the genetic affinity of reference populations across the distribution of Colombian SDTFs. We identify priority source populations for in situ conservation based on their high genetic diversity, lack or limited signs of admixture, and/or genetic uniqueness
Typical median effective radiation doses using an anthropomorphic bone fracture phantom for initial radiographic skeletal surveys in the investigation of suspected physical abuse.
BACKGROUND: A series of 31 radiographs is recommended by the Royal College of Radiologists (RCR) when investigating suspected physical abuse (SPA). OBJECTIVE: To determine the radiation dose delivered for skeletal surveys performed for SPA in Victorian radiology departments based on their local protocols. MATERIALS AND METHODS: A 5-year-old paediatric bone fracture phantom was radiographed at five radiology sites using both the RCR recommended protocol and, where applicable, the local departmental SPA protocol. The radiation doses were measured and recorded. These were scaled down to estimate the effective radiation doses for a 2-year-old child at each site and the associated radiation risks estimated. RESULTS: The median effective dose for all radiographic projections in the RCR skeletal survey radiographic series was 0.09Â mSv. The estimated risk of radiation-induced cancer and radiation-induced death from cancer for 2-year-old children is classified as "very low," with girls having a higher risk than boys. CONCLUSION: The median effective radiation dose for the RCR skeletal survey for imaging in SPA was 0.09Â mSv resulting in a "very low" additional risk of radiation-induced cancer. The authors will now aim to ascertain whether whole-body CT skeletal survey can replace the radiographic series for imaging in SPA while maintaining a comparable radiation dose
Optical Light Curve of the Type Ia Supernova 1998bu in M96 and the Supernova Calibration of the Hubble Constant
We present the UBVRI light curves of the Type Ia supernova SN 1998bu which
appeared in the nearby galaxy M96 (NGC 3368). M96 is a spiral galaxy in the Leo
I group which has a Cepheid-based distance. Our photometry allows us to
calculate the absolute magnitude and reddening of this supernova. These data,
when combined with measurements of the four other well-observed supernovae with
Cepheid based distances, allow us to calculate the Hubble constant with respect
to the Hubble flow defined by the distant Calan/Tololo Type Ia sample. We find
a Hubble constant of 64.0 +/- 2.2(internal) +/- 3.5(external) km/s/Mpc,
consistent with most previous estimates based on Type Ia supernovae. We note
that the two well-observed Type Ia supernovae in Fornax, if placed at the
Cepheid distance to the possible Fornax spiral NGC 1365, are apparently too
faint with respect to the Calan/Tololo sample calibrated with the five Type Ia
supernovae with Cepheid distances to the host galaxies.Comment: AAS LaTeX, 20 pages, 4 figures, 6 tables, accepted for publication in
the Astronomical Journal. Figure 1 (finding chart) not include
Cold Collision Frequency Shift of the 1S-2S Transition in Hydrogen
We have observed the cold collision frequency shift of the 1S-2S transition
in trapped spin-polarized atomic hydrogen. We find , where is the sample density. From this
we derive the 1S-2S s-wave triplet scattering length, nm,
which is in fair agreement with a recent calculation. The shift provides a
valuable probe of the distribution of densities in a trapped sample.Comment: Accepted for publication in PRL, 9 pages, 4 PostScript figures,
ReVTeX. Updated connection of our measurement to theoretical wor
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