On the logic of preference and judgment aggregation

Agents that must reach agreements with other agents need to reason about how their preferences, judgments, and beliefs might be aggregated with those of others by the social choice mechanisms that govern their interactions. The emerging field of judgment aggregation studies aggregation from a logical perspective, and considers how multiple sets of logical formulae can be aggregated to a single consistent set. As a special case, judgment aggregation can be seen to subsume classical preference aggregation. We present a modal logic that is intended to support reasoning about judgment aggregation scenarios (and hence, as a special case, about preference aggregation): the logical language is interpreted directly in judgment aggregation rules. We present a sound and complete axiomatisation. We show that the logic can express aggregation rules such as majority voting; rule properties such as independence; and results such as the discursive paradox, Arrow’s theorem and Condorcet’s paradox—which are derivable as formal theorems of the logic. The logic is parameterised in such a way that it can be used as a general framework for comparing the logical properties of different types of aggregation—including classical preference aggregation. As a case study we present a logical study of, including a formal proof of, the neutrality lemma, the main ingredient in a well-known proof of Arrow’s theorem.     

Reduction of disulfide bonds in an amyloidogenic Bence Jones protein leads to formation of "amyloid-like" fibrils in vitro

Motivated by the finding that the amino acid sequence of the Bence Jones protein BJP-DIA was identical to that of the main protein component of the amyloid fibrils obtained from the same patient with AL-amyloidosis, (Klafki, H.-W., Kratzin, H.-D., Pick, A.-I., Eckart, K., Karas, M. & Hilschmann, N. (1992) Biochemistry 31, 3265-3272.), we attempted to create "amyloid-like" fibrils from the Bence Jones protein in vitro, without addition of proteolytic enzymes. Reduction of BJP-DIA, solubilized in PBS, pH 7.4, overnight at 37 degrees C resulted in the formation of a precipitate which had affinity for the dye Congo red. Electron microscopy of negatively stained samples of the reduced protein revealed aggregates of linear unbranched fibrils. SDS-polyacrylamide gel electrophoresis demonstrated that the precipitate consisted almost exclusively of intact light chain molecules. This result makes it possible to deduce a molecular model of these amyloid fibrils generated in vitro.     

Definition of inseparably fused ventricular myocardium in thoracopagus: fetal echocardiographic utility and pathologic refinement

Correlative echocardiographic and pathological findings in a thoracopagus with conjoined hearts are reported. One twin had tricuspid atresia with discordant atrioventricular connections and concordant ventriculoarterial connections. The morphologic right ventricle was hypoplastic and there was a large muscular ventricular septal defect. The other twin had hypoplasia of the mitral valve anulus and left ventricle with double-outlet right ventricle and pulmonary valve atresia. The tricuspid valve was severely insufficient in part because of a large orifice and redundant, elongated leaflets with abnormal chordal attachments. The left ventricles of these two twins shared a perforated common "free wall" with at least two large defects allowing mixing of the circulations at that level. Not all anatomic details were established conclusively by fetal echocardiography; however, sufficient diagnostic information was obtained to support a decision not to aggressively resuscitate these twins after elective cesarean delivery at 31 weeks' gestation.     

MVA-vaccine in primovaccination against smallpox after the age of three (author's transl)

These are the results of 417 primary vaccinations against smallpox with MVA, an attenuated vaccine. All of the patients were over three years old. In Europe, this group has an increased risk of postvaccinal encephalitis. The intracutaneous inoculation produced a light local infiltration and only 11.7% showed a light generalized reaction. In order to attain a reliable immunity, a second inoculation was performed one week later, epicutaneously with Elstree-vaccine. The local reaction was in general that of a normal revaccination, and 79.4% of our patients had neither fever nor general symptoms. Among the others no one became seriously ill. We did not observe any complications specific for a smallpox vaccination. In comparison to the other vaccination methods currently used, the MVA "Two-step"-vaccination is probably the safest. Its risk of a postvaccinal encephalitis is supposed to be lower according to animal experiments and theoretical considerations. This hypothesis has been confirmed meanwhile by the results of several thousand vaccinations in the already mentioned age-group.     

Software release management for component‐based software

Software release management is the process through which software is made available to and obtained by its users. Until now, this process has been relatively straightforward. However, the emergence of component‐based software is complicating software release management. Increasingly, software is constructed via the assembly of pre‐existing, independently produced, and independently released components. Both developers and users of such software are affected by these complications. Developers need to accurately document the complex and changing dependencies among the components constituting the software. Users must be involved in locating, retrieving, and assembling components in order to appropriately bring the software into their particular environment. In this paper, we introduce the problem of release management for component‐based software and discuss SRM, a prototype software release management tool we have developed that supports both developers and users in the software release management process. Copyright © 2002 John Wiley & Sons, Ltd.     

LPS tolerance in monocytes/macrophages: three 3' cytosins are required in the DNA binding motif for detection of upregulated NF-kappa B p50 homodimers

When monocytes are stimulated with LPS (lipopolysaccharide) repeatedly then the initially high expression of the TNF (tumor necrosis factor) gene is only very low, i.e. the cells are tolerant to LPS. Tolerant cells still express the CD14 receptor and they can still be activated to mobilize NF-kappa B into nucleus. Analysis of the binding proteins employing the -605 motif of the human TNF promoter (GGGGCTGTCCC) revealed that in tolerant cells of the human monocytic cell line Mono Mac 6 there is a predominance of p50p50 of NF-kappa B. We now show that a mutant motif that exchanges the terminal 3' C for a G fails to bind the p50 homodimer that is upregulated in LPS toler ant human Mono Mac 6 cells. The same is true for nuclear extracts taken from the murine P388D1 macrophage cell line when tested with the -516 motif of the murine TNF promoter (GGGGGCTTTCCC). Here the wild type motif gives efficient binding of p50p50 that again is upregulated in tolerant cells whereas a mutant with a 3' G shows hardly any binding of p50p50. Conversely, the murine kappa light chain enhancer motif (GGGGACTTTCCG) does not efficiently bind the nuclear p50p50 from tolerant murine P388 macrophages. Binding is, however, readily detected when the 3' G is replaced by a C. These data show that the detection of upregulated p50 homodimers in LPS tolerant cells is dependent on subtle differences in the sequence of the DNA binding motif.     

Antibiotic susceptibility of Bifidobacterium thermophilum and Bifidobacterium pseudolongum isolates from animal sources

The widespread use of antimicrobial substances has led to resistant populations of microorganisms in several ecosystems. In animal husbandry, the application of antibiotics has contributed to resistance development in pathogenic and commensal bacteria. These strains or their resistance genes can be spread along several ecological routes, including the food chain. Antibiotic resistance is important in terms of the safety of industrial strains, such as probiotics for food and feed. Bifidobacterium thermophilum and Bifidobacterium pseudolongum are known to comprise the major part of the bifidobacterial microbiota in the gut and feces of cattle and pigs. In this study, the antimicrobial susceptibility in bifidobacterial isolates of these species was investigated. Isolates from the beef and pork production chain were identified and typed to strain level, and the antimicrobial susceptibility level was tested to a set of antibiotics. Isolates with low susceptibility levels were screened by PCR for already described resistance genes. Strains atypically resistant to clindamycin, erythromycin, and tetracycline were determined. The resistance genes tet(O), tet(W), and erm(X) were detected in the bifidobacterial species that were examined.     

Land use regression model for ultrafine particles in Amsterdam

There are currently no epidemiological studies on health effects of long-term exposure to ultrafine particles (UFP), largely because data on spatial exposure contrasts for UFP is lacking. The objective of this study was to develop a land use regression (LUR) model for UFP in the city of Amsterdam. Total particle number concentrations (PNC), PM10, PM2.5, and its soot content were measured directly outside 50 homes spread over the city of Amsterdam. Each home was measured during one week. Continuous measurements at a central urban background site were used to adjust the average concentration for temporal variation. Predictor variables (traffic, address density, land use) were obtained using geographic information systems. A model including the product of traffic intensity and the inverse distance to the nearest road squared, address density, and location near the port explained 67% of the variability in measured PNC. LUR models for PM2.5, soot, and coarse particles (PM10, PM2.5) explained 57%, 76%, and 37% of the variability in measured concentrations. Predictions from the PNC model correlated highly with predictions from LUR models for PM2.5, soot, and coarse particles. A LUR model for PNC has been developed, with similar validity as previous models for more commonly measured pollutants.     

The design and evaluation of a tool to support software designers at the whiteboard

Despite the availability of advanced software design tools, software developers are known to frequently turn to the whiteboard when faced with a specific design problem. Free from any restrictions, they engage in an informal form of software design that relies heavily on sketching. However, whereas whiteboards afford flexibility and fluidity, they at the same time limit a designer in only being able to draw and erase content. This paper presents Calico, a novel software design tool that leverages electronic whiteboards to enhance the design experience with explicit support for the creative, exploratory aspects of design. Specifically, Calico offers a grid to partition the drawing space, scraps to organize and manipulate the content, and a reusable palette together with gesture-based input to address several natural behaviors exhibited by software designers, including frequent shifts in focus, use of low-detail models, use of a variety of notations, and a tendency to refine representations. To evaluate Calico, we performed a laboratory experiment involving the design of an educational traffic simulator. Through a three-pronged analysis examining the use of Calico’s features, design behaviors exhibited by the participants, and the nature of the design conversations, we show how Calico benefits the design process as it takes place at the whiteboard.     

Mapping of background air pollution at a fine spatial scale across the European Union

Background

There is a need to understand much more about the geographic variation of air pollutants. This requires the ability to extrapolate from monitoring stations to unsampled locations. The aim was to assess methods to develop accurate and high resolution maps of background air pollution across the EU.

Methods

We compared the validity of ordinary kriging, universal kriging and regression mapping in developing EU-wide maps of air pollution on a 1 × 1 km resolution. Predictions were made for the year 2001 for nitrogen dioxide (NO₂), fine particles < 10 µm (PM₁₀), ozone (O₃), sulphur dioxide (SO₂) and carbon monoxide (CO) using routine monitoring data in Airbase. Predictor variables from EU-wide databases were land use, road traffic, population density, meteorology, altitude, topography and distance to sea. Models were developed for the global, rural and urban scale separately. The best method to model concentrations was selected on the basis of predefined performance measures (R², Root Mean Square Error (RMSE)).

Results

For NO₂, PM₁₀ and O₃ universal kriging performed better than regression mapping and ordinary kriging. Validation of the final universal kriging estimates with results from all validation sites gave R²-values and RMSE-values of 0.61 and 6.73 µg/m³ for NO₂; 0.45 and 5.19 µg/m³ for PM₁₀; and 0.70 and 7.69 µg/m³ for O₃. For SO₂ and CO none of the three methods was able to provide a satisfactory prediction.

Conclusion

Reasonable prediction models were developed for NO₂, PM₁₀ and O₃ on an EU-wide scale. Our study illustrates that it is possible to develop detailed maps of background air pollution using EU-wide databases.