A widely tunable few electron droplet

Quasi-static transport measurements are employed to characterize a few electron quantum dot electrostatically defined in a GaAs/AlGaAs heterostructure. The gate geometry allows observations on one and the same electron droplet within a wide range of coupling strengths to the leads. The weak coupling regime is described by discrete quantum states. At strong interaction with the leads Kondo phenomena are observed as a function of a magnetic field. By varying gate voltages the electron droplet can, in addition, be distorted into a double quantum dot with a strong interdot tunnel coupling while keeping track of the number of trapped electrons.Comment: 11 pages, 5 figure

Methodological Individualism, the We-mode, and Team Reasoning

Raimo Tuomela is one of the pioneers of social action theory and has done as much as anyone over the last thirty years to advance the study of social action and collective intentionality. Social Ontology: Collective Intentionality and Group Agents (2013) presents the latest version of his theory and applications to a range of important social phenomena. The book covers so much ground, and so many important topics in detailed discussions, that it would impossible in a short space to do it even partial justice. In this brief note, I will concentrate on a single, though important, theme in the book, namely, the claim that we must give up methodological individualism in the social sciences and embrace instead irreducibly group notions. I wish to defend methodological individualism as up to the theoretical tasks of the social sciences while acknowledging what is distinctive about the social world and collective intentional action. Tuomela frames the question of the adequacy of methodological individualism in terms of a contrast between what he calls the I-mode and the we-mode. He argues that we-mode phenomena are not reducible to I-mode phenomena, and concludes that we must reject methodological individualism. I will argue that the irreducibility of the we-mode to the I-mode, given how the contrast is set up, does not entail the rejection of methodological individualism. In addition, I will argue that the three conditions that Tuomela places on genuine we-mode activities, the group reason, collectivity, and collective commitment conditions, if they are understood in a way that does not beg the question, can plausibly be satisfied by a reductive account. Finally, I will argue that the specific considerations advanced in the book do not give us reason to think that a reductive account cannot be adequate to the descriptive and explanatory requirements of a theory of the social worl

Stellar granulation as seen in disk-integrated intensity. I. Simplified theoretical modeling

The solar granulation is known for a long time to be a surface manifestation of convection. Thanks to the current space-borne missions CoRoT and Kepler, it is now possible to observe in disk-integrated intensity the signature of this phenomena in a growing number of stars. The space-based photometric measurements show that the global brightness fluctuations and the lifetime associated with granulation obeys characteristic scaling relations. We thus aim at providing a simple theoretical modeling to reproduce these scaling relations and subsequently at inferring the physical properties of granulation properties across the HR diagram. We develop a simple 1D theoretical model that enable us to test any prescription concerning the time-correlation between granules. The input parameters of the model are extracted from 3D hydrodynamical models of the surface layers of stars, and the free parameters involved in the model are calibrated with solar observations. Two different prescriptions for representing the eddy time-correlation in the Fourier space are compared: a Lorentzian and an exponential form. Finally, we compare our theoretical prediction with a 3D radiative hydrodynamical (RHD) numerical modeling of stellar granulation (ab-initio approach). Provided that the free parameters are appropriately adjusted, our theoretical model satisfactorily reproduces the shape and the amplitude of the observed solar granulation spectrum. The best agreement is obtained with an exponential form. Furthermore, our theoretical model results in granulation spectra that consistently agree with the these calculated on the basis of the ab-initio approach with two 3D RHD models. Comparison between theoretical granulation spectra calculated with the present model and high precision photometry measurements of stellar granulation is undertaken in a companion paper.Comment: 10 pages, 2 figures, accepted for publication in A&

Extreme Fire as a Management Tool to Combat Regime Shifts in the Range of the Endangered American Burying Beetle

This study is focused on the population of federally-endangered American burying beetles in south-central Nebraska. It is focused on changes in land cover over time and at several levels of spatial scale, and how management efforts are impacting both the beetle and a changing landscape. Our findings are applicable to a large portion of the Great Plains, which is undergoing the same shift from grassland to woodland, and to areas where the beetle is still found

CrossFlow: Integrating Workflow Management and Electronic Commerce

The CrossFlow1 architecture provides support for cross-organisational workflow management in dynamically established virtual enterprises. The creation of a business relationship between a service provider organisation performing a service on behalf of a consumer organisation can be made dynamic when augmented by virtual market technology, the dynamic configuration of the contract enactment infrastructures, and the provision of fine grained service monitoring and control. Standard ways of describing services and contracts can be combined with matchmaking technology to create a virtual market for such service provision and consumption. A provider can then advertise its services in the market and consumers can search for a compatible business partner. This provides choice in selecting a partner and allows the deferment of the decision to a point in time where it can be made on the most up-to-date requirements of the consumer and service offers in the market. The penalty for deferred decision making is the time to set up the infrastructure in each organisation for the dynamically established contract. Thus, a further aspect of CrossFlow was to exploit the contract in the dynamic and automatic configuration of the contract enactment and supervision infrastructures of the respective organisations and in linking them in a dynamic fashion. The electronic contract, which results from the agreement between the newly established business partners, completely specifies the intended collaboration between them. Given the importance of the business process enacted by the provider, this includes fine-grained monitoring and control to allow tight co-operation between the organisations

KINEMATIC ANALYSIS OF SOCCER HEADING TECHNIQUE

The purpose of this investigation was to determine if collegiate players who head the ball frequently (FH) use a different technique than collegiate players who head the ball infrequently (IH). Twenty-four women’s collegiate soccer players with at least 9 years of soccer heading experience were separated into FH and IH groups. Ten maximal standing headers were videotaped. The FH group had significantly larger change in ball velocity, trunk ROM, and neck and trunk angular velocity at contact. It was concluded that women who headed the ball frequently used a different technique than women who head the ball infrequently. This difference in technique was best manifested in the change in ball velocity from pre-contact to post-contact

Entanglement of mechanical oscillators coupled to a non-equilibrium environment

Recent experiments aim at cooling nanomechanical resonators to the ground state by coupling them to non-equilibrium environments in order to observe quantum effects such as entanglement. This raises the general question of how such environments affect entanglement. Here we show that there is an optimal dissipation strength for which the entanglement between two coupled oscillators is maximized. Our results are established with the help of a general framework of exact quantum Langevin equations valid for arbitrary bath spectra, in and out of equilibrium. We point out why the commonly employed Lindblad approach fails to give even a qualitatively correct picture

Cyber Security Awareness Among College Students

This study reports the early results of a study aimed to investigate student awareness and attitudes toward cyber security and the resulting risks in the most advanced technology environment: the Silicon Valley in California, USA. The composition of students in Silicon Valley is very ethnically diverse. The objective was to see how much the students in such a tech-savvy environment are aware of cyber-attacks and how they protect themselves against them. The early statistical analysis suggested that college students, despite their belief that they are observed when using the Internet and that their data is not secure even on university systems, are not very aware of how to protect their data. Also, it appears that educational institutions do not have an active approach to improve awareness among college students to increase their knowledge on these issues and how to protect themselves from potential cyber-attacks, such as identity theft or ransomware