Demonstration of an electrostatic-shielded cantilever

The fabrication and performances of cantilevered probes with reduced parasitic capacitance starting from a commercial Si3N4 cantilever chip is presented. Nanomachining and metal deposition induced by focused ion beam techniques were employed in order to modify the original insulating pyramidal tip and insert a conducting metallic tip. Two parallel metallic electrodes deposited on the original cantilever arms are employed for tip biasing and as ground plane in order to minimize the electrostatic force due to the capacitive interaction between cantilever and sample surface. Excitation spectra and force-to-distance characterization are shown with different electrode configurations. Applications of this scheme in electrostatic force microscopy, Kelvin probe microscopy and local anodic oxidation is discussed.Comment: 4 pages and 3 figures. Submitted to Applied Physics Letter

Principal Semantic Components of Language and the Measurement of Meaning

Metric systems for semantics, or semantic cognitive maps, are allocations of words or other representations in a metric space based on their meaning. Existing methods for semantic mapping, such as Latent Semantic Analysis and Latent Dirichlet Allocation, are based on paradigms involving dissimilarity metrics. They typically do not take into account relations of antonymy and yield a large number of domain-specific semantic dimensions. Here, using a novel self-organization approach, we construct a low-dimensional, context-independent semantic map of natural language that represents simultaneously synonymy and antonymy. Emergent semantics of the map principal components are clearly identifiable: the first three correspond to the meanings of “good/bad” (valence), “calm/excited” (arousal), and “open/closed” (freedom), respectively. The semantic map is sufficiently robust to allow the automated extraction of synonyms and antonyms not originally in the dictionaries used to construct the map and to predict connotation from their coordinates. The map geometric characteristics include a limited number (∼4) of statistically significant dimensions, a bimodal distribution of the first component, increasing kurtosis of subsequent (unimodal) components, and a U-shaped maximum-spread planar projection. Both the semantic content and the main geometric features of the map are consistent between dictionaries (Microsoft Word and Princeton's WordNet), among Western languages (English, French, German, and Spanish), and with previously established psychometric measures. By defining the semantics of its dimensions, the constructed map provides a foundational metric system for the quantitative analysis of word meaning. Language can be viewed as a cumulative product of human experiences. Therefore, the extracted principal semantic dimensions may be useful to characterize the general semantic dimensions of the content of mental states. This is a fundamental step toward a universal metric system for semantics of human experiences, which is necessary for developing a rigorous science of the mind

High incidence of classic Kaposi's sarcoma in Mantua, Po Valley, Northern Italy (1989–1998)

The incidence of classic Kaposi's sarcoma was estimated in the province of Mantua, Po Valley, Northern Italy, yielding age-standardized rates of 2.5/100 000 men and 0.7/100 000 women (1989–98). Elevated rates in the rural zone of Viadana/Sabbioneta (5.0/100 000 men and 2.8/100 000 women) are among the highest so far reported for Italian communities. © 2001 Cancer Research Campaign http://www.bjcancer.co

High-resolution saturation spectroscopy of singly-ionized iron with a pulsed uv laser

We describe the design and realization of a scheme for uv laser spectroscopy of singly-ionized iron (Fe II) with very high resolution. A buffer-gas cooled laser ablation source is used to provide a plasma close to room temperature with a high density of Fe II. We combine this with a scheme for pulsed-laser saturation spectroscopy to yield sub-Doppler resolution. In a demonstration experiment, we have examined an Fe II transition near 260 nm, attaining a linewidth of about 250 MHz. The method is well-suited to measuring transition frequencies and hyperfine structure. It could also be used to measure small isotope shifts in isotope-enriched samples.Comment: 9 pages, 5 figures, updated Fig. 3. For submission to J. Phys.

Augmenting Weak Semantic Cognitive Maps with an “Abstractness” Dimension

The emergent consensus on dimensional models of sentiment, appraisal, emotions, and values is on the semantics of the principal dimensions, typically interpreted as valence, arousal, and dominance. The notion of weak semantic maps was introduced recently as distribution of representations in abstract spaces that are not derived from human judgments, psychometrics, or any other a priori information about their semantics. Instead, they are defined entirely by binary semantic relations among representations, such as synonymy and antonymy. An interesting question concerns the ability of the antonymy-based semantic maps to capture all “universal” semantic dimensions. The present work shows that those narrow weak semantic maps are not complete in this sense and can be augmented with other semantic relations. Specifically, including hyponym-hypernym relations yields a new semantic dimension of the map labeled here “abstractness” (or ontological generality) that is not reducible to any dimensions represented by antonym pairs or to traditional affective space dimensions. It is expected that including other semantic relations (e.g., meronymy/holonymy) will also result in the addition of new semantic dimensions to the map. These findings have broad implications for automated quantitative evaluation of the meaning of text and may shed light on the nature of human subjective experience

Human herpesvirus 8-associated primary effusion lymphoma in human immunodeficiency virus-negative patients: a clinico-epidemiologic variant resembling classic Kaposi's sarcoma

No abstract availabl

HHV-8 transmission via saliva to soothe blood-sucking arthropod bites

The British Journal of Cance

Uncovering current pyroregions in Italy using wildfire metrics

Background: Pyrogeography is a major field of investigation in wildfire science because of its capacity to describe the spatial and temporal variations of fire disturbance. We propose a systematic pyrogeographic analytical approach to cluster regions on the basis of their pyrosimilarities. We employed the Affinity Propagation algorithm to cluster pyroregions using Italian landscape as a test bed and its current wildfire metrics in terms of density, seasonality and stand replacing fire ratio. A discussion follows on how pyrogeography varies according to differences in the human, biophysical, socioeconomic, and climatic spheres. Results: The algorithm identified seven different pyroregion clusters. Two main gradients were identified that partly explain the variability of wildfire metrics observed in the current pyroregions. First, a gradient characterized by increasing temperatures and exposure to droughts, which coincides with a decreasing latitude, and second, a human pressure gradient displaying increasing population density in areas at lower elevation. These drivers exerted a major influence on wildfire density, burnt area over available fuels and stand replacing, which were associated to warm-dry climate and high human pressure. The study statistically highlighted the importance of a North–South gradient, which represents one of the most important drivers of wildfire regimes resulting from the variations in climatic conditions but showing collinearity with socioeconomic aspects as well. Conclusion: Our fully replicable analytical approach can be applied at multiple scales and used for the entire European continent to uncover new and larger pyroregions. This could create a basis for the European Commission to promote innovative and collaborative funding programs between regions that demonstrate pyrosimilarities

Upper Limit on the Magnetic Dipole Contribution to the 5p-8p Transition in Rb by Use of Ultracold Atom Spectroscopy

We report on hyperfine-resolved spectroscopic measurements of the electric-dipole forbidden 5$p_{3/2} \to 8p_{1/2}$ transition in a sample of ultracold $^{87}$Rb atoms. The hyperfine selection rules enable the weak magnetic-dipole (M1) contribution to the transition strength to be distinguished from the much stronger electric-quadrupole (E2) contribution. An upper limit on the M1 transition strength is determined that is about 50 times smaller than an earlier experimental determination. We also calculate the expected value of the M1 matrix element and find that it is less than the upper limit extracted from the experiment.Comment: 7 pages, 4 figures, 3 table