Detecting mistakes in engineering models: the effects of experimental design

This paper presents the results of an experiment with human subjects investigating their ability to discover a mistake in a model used for engineering design. For the purpose of this study, a known mistake was intentionally placed into a model that was to be used by engineers in a design process. The treatment condition was the experimental design that the subjects were asked to use to explore the design alternatives available to them. The engineers in the study were asked to improve the performance of the engineering system and were not informed that there was a mistake intentionally placed in the model. Of the subjects who varied only one-factor-at-a-time, fourteen of the twenty-seven independently identified the mistake during debriefing after the design process. A much lower fraction, one out of twenty-seven engineers, independently identified the mistake during debriefing when they used a fractional factorial experimental design. Regression analysis shows that relevant domain knowledge improved the ability of subjects to discover mistakes in models, but experimental design had a larger effect than domain knowledge in this study. Analysis of video tapes provided additional confirmation as the likelihood of subjects to appear surprised by data from a model was significantly different across the treatment conditions. This experiment suggests that the complexity of factor changes during the design process is a major consideration influencing the ability of engineers to critically assess models.Charles Stark Draper LaboratorySUTD-MIT International Design Centr

Role of wintertime radiation in maintaining and destroying stable layers, The

July 1993.Includes bibliographical references.Sponsored by National Science Foundation ATM-9113898.Sponsored by NOAA Cooperative Agreement A 90-RAH00077

Diamagnetism of quantum gases with singular potentials

We consider a gas of quasi-free quantum particles confined to a finite box, subjected to singular magnetic and electric fields. We prove in great generality that the finite volume grand-canonical pressure is jointly analytic in the chemical potential ant the intensity of the external magnetic field. We also discuss the thermodynamic limit

Regioselective and stoichiometrically controlled conjugation of photodynamic sensitizers to a HER2 targeting antibody fragment

The rapidly increasing interest in the synthesis of antibody–drug conjugates as powerful targeted anticancer agents demonstrates the growing appreciation of the power of antibodies and antibody fragments as highly selective targeting moieties. This targeting ability is of particular interest in the area of photodynamic therapy, as the applicability of current clinical photosensitizers is limited by their relatively poor accumulation in target tissue in comparison to healthy tissue. Although synthesis of porphyrin–antibody conjugates has been previously demonstrated, existing work in this area has been hindered by the limitations of conventional antibody conjugation methods. This work describes the attachment of azide-functionalized, water-soluble porphyrins to a tratuzumab Fab fragment via a novel conjugation methodology. This method allows for the synthesis of a homogeneous product without the loss of structural stability associated with conventional methods of disulfide modification. Biological evaluation of the synthesized conjugates demonstrates excellent selectivity for a HER2 positive cell line over the control, with no dark toxicity observed in either case

Vitamin D Levels in Patients with Colorectal Cancer and Matched Household Members.

BackgroundVitamin D levels, as measured by 25-hydroxyvitamin-D [25(OH) D], are inversely related to the risk of developing colorectal cancer (CRC). Given shared demographic and lifestyle factors among members of the same household, we sought to examine vitamin D levels and associated lifestyle factors in household members of CRC patients.MethodsThirty patients with pathologically confirmed CRC were enrolled prior to oncologic therapy along with unrelated household members who were matched for age (+/- 5 years) and race. In addition to serum blood draws for 25(OH)D levels at baseline and six-month follow-up, questionnaires collected gender, vitamin use, body mass index, family history of CRC, race, dietary vitamin D, UV exposure, and exercise.ResultsMedian serum 25(OH) D levels were 26.8 ng/mL for CRC patients versus 27.3 for household members (P=0.89). Vitamin-D associated factors such as dietary vitamin D intake, UV exposure, gender, multivitamin use, vitamin D supplement use, and family history of CRC were not significantly different between CRC patients and paired household members (P>0.05). Household members were more likely than CRC patients to be overweight and to exercise more.ConclusionsVitamin D levels and many associated lifestyle factors were not significantly different between CRC patients and unrelated paired household members. Given comparable vitamin D levels, further investigation into whether age-matched household members of CRC patients may be at increased risk for CRC is warranted

C-type natriuretic peptide and brain natriuretic peptide inhibit adenylyl cyclase activity: interaction with ANF-R2/ANP-C receptors

AbstractC-type natriuretic peptide (CNP) and brain natriuretic peptide (BNP) are members of the natriuretic peptide family, which have been shown to interact with ANP-C/ANF-R2 receptors in addition to ANP-B receptor subtypes. The present study was undertaken to investigate if the interaction of CNP and BNP with ANP-C receptors results in the inhibition of adenylyl cyclase activity. CNP and BNP inhibited adenylyl cyclase activity in heart and brain striatal membranes in a concentration dependent manner with an apparent Ki between 0.1 and 1.0 nM. Maximal inhibition observed in heart membranes were about 25% and 35% for BNP and CNP respectively, however the inhibitions in brain striatal membranes were smaller (∼2%). The inhibition was dependent on the presence of guanine nucleotides and was attenuated by pertussis toxin treatment. In addition, CNP inhibited the stimulatory effect of isoproterenol on adenylyl cyclase, whereas CNP as well as BNP showed an additive effect with the inhibitory response of angiotensin II on adenylyl cyclase activity. When the combined effect of C-ANF4−23/BNP, C-ANF4−23/CNP and BNP/CNP at optimal concentrations was studied together on adenylyl cyclase activity, the percent inhibition remained the same for C-ANF4−23 and BNP or C-ANF4−23 and CNP, however, an additive inhibitory effect was observed for BNP and CNP. These results suggest that CNP and BNP like C-ANF4−23 interact with ANP-C receptors and result in the inhibition of adenylyl cyclase activity. On the other hand, CNP and BNP interact with the ANP-C receptor, however, the interaction may be at different sites or there may be two subpopulations of ANP-C receptors specific for each of the peptides. These results indicate that BNP and CNP, like ANP and C-ANF4−23, inhibit the adenylyl cyclase/cAMP signal transduction system through an inhibitory guanine nucleotide regulatory protein, by interacting with ANP-C receptor subtypes

Comparisons of trace constituents from ground stations and the DC-8 aircraft during PEM-West B

Chemical data from ground stations in Asia and the North Pacific are compared with data from the DC-8 aircraft collected during the Pacific Exploratory Measurements in the Western Pacific Ocean (PEM-West B) mission. Ground station sampling took place on Hong Kong, Taiwan, Okinawa, and Cheju; and at three Pacific islands, Shemya, Midway, and Oahu. Aircraft samples were collected during 19 flights, most over the western North Pacific. Aluminum was used as an indicator of mineral aerosol, and even though the aircraft did sample Asian dust, strong dust storms were not encountered. The frequency distribution for non-sea-salt sulfate (nss SO4=) in the aircraft samples was bimodal: the higher concentration mode (∼1 μg m−3) evidently originated from pollution or, less likely, from volcanic sources, while the lower mode, with a peak at 0.040 μg m−3, probably was a product of biogenic emissions. In addition, the concentrations of aerosol sulfate varied strongly in the vertical: arithmetic mean SO4=concentrations above 5000 m ( = 0.21±0.69 μg m−3) were substantially lower than those below ( = 1.07±0.87 μg m−3), suggesting the predominance of the surface sources. Several samples collected in the stratosphere exhibited elevated SO4=, however, probably as a result of emissions from Mount Pinatubo. During some boundary layer legs on the DC-8, the concentrations of CO and O3 were comparable to those of clean marine air, but during other legs, several chemically distinct air masses were sampled, including polluted air in which O3was photochemically produced. In general, the continental outflow sampled from the aircraft was substantially diluted with respect to what was observed at the ground stations. Higher concentrations of aerosol species, O3, and CO at the Hong Kong ground station relative to the aircraft suggest that much of the continental outflow from southeastern Asia occurs in the lower troposphere, and extensive long-range transport out of this part of Asia is not expected. In comparison, materials emitted farther to the north apparently are more susceptible to long-range transport

Matter-wave laser Interferometric Gravitation Antenna (MIGA): New perspectives for fundamental physics and geosciences

The MIGA project aims at demonstrating precision measurements of gravity with cold atom sensors in a large scale instrument and at studying the associated applications in geosciences and fundamental physics. The first stage of the project (2013-2018) will consist in building a 300-meter long optical cavity to interrogate atom interferometers and will be based at the low noise underground laboratory LSBB in Rustrel, France. The second stage of the project (2018-2023) will be dedicated to science runs and data analyses in order to probe the spatio-temporal structure of the local gravity field of the LSBB region, a site of high hydrological interest. MIGA will also assess future potential applications of atom interferometry to gravitational wave detection in the frequency band $\sim 0.1-10$ Hz hardly covered by future long baseline optical interferometers. This paper presents the main objectives of the project, the status of the construction of the instrument and the motivation for the applications of MIGA in geosciences. Important results on new atom interferometry techniques developed at SYRTE in the context of MIGA and paving the way to precision gravity measurements are also reported.Comment: Proceedings of the 50th Rencontres de Moriond "100 years after GR", La Thuile (Italy), 21-28 March 2015 - 10 pages, 5 figures, 23 references version2: added references, corrected typo

Elevated atmospheric sulfur levels off the Peruvian coast

Elevated levels of non‐sea‐salt sulfate and SO2 in samples collected off the west coast of South America indicate that there is a major source of atmospheric sulfur in the region of southern Peru and northern Chile. During a 1983 cruise, observed concentrations of non‐sea‐salt sulfur, SO2, selenium, arsenic, and antimony were comparable to levels reported for moderately polluted urban air. In contrast, methanesulfonic acid levels were typical of coastal marine air. Clearly, the elevated atmospheric sulfur levels in this region cannot be ascribed to oceanic organosulfur emissions. The major inputs are tentatively attributed to the smelting of sulfide ores which is a major industry in this region. The transport of smelter derived aerosols to this region may have a number of consequences for the atmospheric and oceanic chemistry of the Peruvian upwelling area

Comparisons of trace constituents from ground stations and the DC‐8 aircraft during PEM‐West B

Chemical data from ground stations in Asia and the North Pacific are compared with data from the DC‐8 aircraft collected during the Pacific Exploratory Measurements in the Western Pacific Ocean (PEM‐West B) mission. Ground station sampling took place on Hong Kong, Taiwan, Okinawa, and Cheju; and at three Pacific islands, Shemya, Midway, and Oahu. Aircraft samples were collected during 19 flights, most over the western North Pacific. Aluminum was used as an indicator of mineral aerosol, and even though the aircraft did sample Asian dust, strong dust storms were not encountered. The frequency distribution for non‐sea‐salt sulfate (nss SO4=) in the aircraft samples was bimodal: the higher concentration mode (∼1 μg m−3) evidently originated from pollution or, less likely, from volcanic sources, while the lower mode, with a peak at 0.040 μg m−3, probably was a product of biogenic emissions. In addition, the concentrations of aerosol sulfate varied strongly in the vertical: arithmetic mean SO4= concentrations above 5000 m ( = 0.21±0.69 μg m−3) were substantially lower than those below ( = 1.07±0.87 μg m−3), suggesting the predominance of the surface sources. Several samples collected in the stratosphere exhibited elevated SO4=, however, probably as a result of emissions from Mount Pinatubo. During some boundary layer legs on the DC‐8, the concentrations of CO and O3 were comparable to those of clean marine air, but during other legs, several chemically distinct air masses were sampled, including polluted air in which O3 was photochemically produced. In general, the continental outflow sampled from the aircraft was substantially diluted with respect to what was observed at the ground stations. Higher concentrations of aerosol species, O3, and CO at the Hong Kong ground station relative to the aircraft suggest that much of the continental outflow from southeastern Asia occurs in the lower troposphere, and extensive long‐range transport out of this part of Asia is not expected. In comparison, materials emitted farther to the north apparently are more susceptible to long‐range transport