8,477 research outputs found
Contact Surface Area: A Novel Signal for Heart Rate Estimation in Smartphone Videos
We consider the problem of smartphone video-based heart rate estimation,
which typically relies on measuring the green color intensity of the user's
skin. We describe a novel signal in fingertip videos used for smartphone-based
heart rate estimation: fingertip contact surface area. We propose a model
relating contact surface area to pressure, and validate it on a dataset of 786
videos from 62 participants by demonstrating a statistical correlation between
contact surface area and green color intensity. We estimate heart rate on our
dataset with two algorithms, a baseline using the green signal only and a novel
algorithm based on both color and area. We demonstrate lower rates of
substantial errors (>10 beats per minute) using the novel algorithm (4.1%),
compared both to the baseline algorithm (6.4%) and to published results using
commercial color-based applications (>6%)
A search for spectral alteration effects in chondritic gas-rich breccias
Several samples of gas-rich breccias were selected, including slabs of the Kapoeta howardite, the ordinary chondrites Dubrovnik, Cangas de Onis, and Dimmit. Numerous 0.8 to 2.5 micron reflection spectra of selected areas on sawed or broken surfaces were measured with the Planetary Geosciences Division spectrogoniometer. While these spectra are not directly comparable to those of powered samples, comparisons within the data set should reveal any spectral differences due to weathering. These results indicate that unknown regolith processes do not confer the ordinary-chondrite parent bodies with an altered layer exhibiting S-class spectral properties. This is consistent with recent interpretations of the new Q-class of asteroids as the ordinary-chondrite parent bodies. However, significant spectral effects do occur in asteroid regoliths: darkening and suppression of absorption bands in highly shocked material, as seen previously in the so-called black chondrites; and segregation of metal in large impact melt pools on chondritic asteroids, which may have achondritic spectra. Neither of these effects is likely to be significant in interpreting current integral-disk spectra, but should be searched for in spectral maps returned by future spacecraft
Can retinal ganglion cell dipoles seed iso-orientation domains in the visual cortex?
It has been argued that the emergence of roughly periodic orientation
preference maps (OPMs) in the primary visual cortex (V1) of carnivores and
primates can be explained by a so-called statistical connectivity model. This
model assumes that input to V1 neurons is dominated by feed-forward projections
originating from a small set of retinal ganglion cells (RGCs). The typical
spacing between adjacent cortical orientation columns preferring the same
orientation then arises via Moir\'{e}-Interference between hexagonal ON/OFF RGC
mosaics. While this Moir\'{e}-Interference critically depends on long-range
hexagonal order within the RGC mosaics, a recent statistical analysis of RGC
receptive field positions found no evidence for such long-range positional
order. Hexagonal order may be only one of several ways to obtain spatially
repetitive OPMs in the statistical connectivity model. Here, we investigate a
more general requirement on the spatial structure of RGC mosaics that can seed
the emergence of spatially repetitive cortical OPMs, namely that angular
correlations between so-called RGC dipoles exhibit a spatial structure similar
to that of OPM autocorrelation functions. Both in cat beta cell mosaics as well
as primate parasol receptive field mosaics we find that RGC dipole angles are
spatially uncorrelated. To help assess the level of these correlations, we
introduce a novel point process that generates mosaics with realistic nearest
neighbor statistics and a tunable degree of spatial correlations of dipole
angles. Using this process, we show that given the size of available data sets,
the presence of even weak angular correlations in the data is very unlikely. We
conclude that the layout of ON/OFF ganglion cell mosaics lacks the spatial
structure necessary to seed iso-orientation domains in the primary visual
cortex.Comment: 9 figures + 1 Supplementary figure and 1 Supplementary tabl
State-sponsored populism and the rise of populistgovernance: the case of Montenegro
Ever since it became independent in 2006, Montenegro has steadily progressed in its ambition to accede to the European Union. Even so, a new form of populism, dominated by neither a far-right nor a far-left discourse, but controlled by leading political elites in the country’s government has developed in Montenegro. This form of populism is not a mechanism of ensuring the dominance of the Democratic Party of Socialists (Demokratska Partija Socijalista Crne Gore, DPS) in Montenegro per se. Instead it is used as a tool to support and enhance other mechanisms that the party utilizes in order to stay in power and remain the dominant force in the country. Hence, we can observe the growth of a new kind of populism, a state-sponsored populist discourse that is very different from populism as understood in Western Europe. What we find in Montenegro is a government that
uses populist language and messages to support a clientelistic state system
The cytolytic T lymphocyte response to the murine cytomegalovirus
Limiting dilution (LD) analysis with two modifications, the expansion and the restimulation LD assay, led to the detection and quantification of two distinct in vivo maturation stages within the lineage of virus- specific self-restricted CTL after infection of mice with the murine cytomegalovirus (MCMV). A low frequency set, representing an average of 15% of the specifically activated CTL-P in a draining lymph node, generated virus-specific lytic activity in the absence of antigen, solely under expansion conditions provided by growth and differentiation interleukins. These cells were considered to be active and were denoted antigen-independent or interleukin-receptive CTL-P (IL- CTL-P). A high frequency set required additional antigen in vitro to generate functionally active clones, and therefore the cells were termed antigen-dependent. Both sets are present in vivo simultaneously at the peak of the acute immune response and represent antigen- activated cells because their existence strictly depends on a preceding priming event. IL-CTL-P disappear quickly after acute infection and are absent during the memory state. It is proposed that the isolation of IL- CTL-P could serve to detect viral antigen expression during persistent and/or recurrent herpes virus infections
Change amidst continuity? Assessing the 2018 regional elections in Bosnia and Herzegovina
Looking at regional elections in Bosnia and Herzegovina (BiH) is a complex task. It requires a simultaneous discussion of nationalization and congruence in Bosnian elections, the role of civic parties, the role of regional elections in overall party system fragmentation, and the impact of federalism and power-sharing on peace-building and state-building. For this paper, we use two primary analytical lenses. The first and most emphasized lens will be on developments in political competition within cantons and entities, and therefore largely within ethnic blocs. Due to limits imposed by power-sharing at the central state level, regional elections are where competition is most dynamic and responsive to voters. Of particular interest are challenges to SNSD’s (Alliance of Independent Social Democrats- Savez nezavisnih socijaldemokrata) predominant position in Republika Srpska in light of very visible popular protest against Milorad Dodik and his party, as well as the impact of ongoing fragmentation of civic parties in the Federation and canton elections. The second lens is the analysis of continuity and change in the linkage between canton and entity elections on the one hand and BiH-level elections on the other. This interaction is the driving force behind the distinctive features of the Bosnian party system, namely its high degree of congruence within regions and low congruence across regions, which results in a highly fragmented party system at the central state level. This paper includes a discussion of entity and cantonal elections in Bosnia in 2018, embedded in the discourse of party system change and continuity as well as congruence and fragmentation. However, we also link this discussion to BiH-level elections to demonstrate how peculiar the country is, but also how the elections at a regional and cantonal level help explain some of the problems of Bosnia as a whole
Ideology and party system change in consociational systems: the case of non-nationalist parties in Bosnia and Herzegovina
Following a period of nationalist party dominance in Bosnia and Herzegovina, alternative parties have emerged to challenge the established parties with ideologies that seek to bridge ethnic divides.
This paper examines the ideological positioning of non-nationalist parties relative to nationalist parties and the challenges for such parties in supplanting the dominance of ethnicity in politics. Based on elite interviews and detailed analysis of party documents, we argue that these parties have identified sufficient electoral support for alternative conceptions of politics and inter-ethnic relations in post-war Bosnia to promote their non-nationalist agendas. The parties couple distinct non-nationalist ideas with ideological formulations that have the potential to bridge across ethnic groups. However, the stability in support for non-nationalist parties, even as individual parties with distinct ideologies rise or fall, suggests that the appeal of this approach is limited by the necessity of governing with nationalist parties and the appeal of state contestation
Nonperturbative analysis of coupled quantum dots in a phonon bath
Transport through coupled quantum dots in a phonon bath is studied using the
recently developed real-time renormalization-group method. Thereby, the problem
can be treated beyond perturbation theory regarding the complete interaction. A
reliable solution for the stationary tunnel current is obtained for the case of
moderately strong couplings of the dots to the leads and to the phonon bath.
Any other parameter is arbitrary, and the complete electron-phonon interaction
is taken into account. Experimental results are quantitatively reproduced by
taking into account a finite extension of the wavefunctions within the dots.
Its dependence on the energy difference between the dots is derived.Comment: 8 pages, 6 figure
Diffusion in a crowded environment
We analyze a pair of diffusion equations which are derived in the infinite
system--size limit from a microscopic, individual--based, stochastic model.
Deviations from the conventional Fickian picture are found which ultimately
relate to the depletion of resources on which the particles rely. The
macroscopic equations are studied both analytically and numerically, and are
shown to yield anomalous diffusion which does not follow a power law with time,
as is frequently assumed when fitting data for such phenomena. These anomalies
are here understood within a consistent dynamical picture which applies to a
wide range of physical and biological systems, underlining the need for clearly
defined mechanisms which are systematically analyzed to give definite
predictions.Comment: 4 pages, 3 figures, minor change
Teleological Essentialism: Generalized
Natural/social kind essentialism is the view that natural kind categories, both living and non-living natural kinds, as well as social kinds (e.g., race, gender), are essentialized. On this view, artifactual kinds are not essentialized. Our view—teleological essentialism—is that a broad range of categories are essentialized in terms of teleology, including artifacts. Utilizing the same kinds of experiments typically used to provide evidence of essentialist thinking—involving superficial change (study 1), transformation of insides (study 2) and inferences about offspring (study 3)—we find support for the view that a broad range of categories—living natural kinds, non-living natural kinds and artifactual kinds—are essentialized in terms of teleology. Study 4 tests a unique prediction of teleological essentialism and also provides evidence that people make inferences about purposes which in turn guide categorization judgments
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